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Skills for Work:Energy

Intermediate 2

September 2008

Domestic Wind Turbines Systems

Support Material

Energy: Domestic Wind Turbines Systems – (Intermediate 2)

Scottish Further Education Unit 3

Acknowledgements SFEU is grateful to the subject specialists in Scotland’s Colleges and other agencies and industry bodies who have been involved in the writing of this and other support materials in the Skills for Work series. SFEU is also grateful for the contribution of the Scottish Qualifications Authority in the compilation of these materials, specifically for its permission to reproduce extracts from Course and Unit Specifications and the Skills for Work Rationale. © Scottish Further Education Unit 2008 Scottish Further Education Unit (SFEU) Argyll Court Castle Business Park Stirling FK9 4TY website: www.sfeu.ac.uk e-mail: [email protected] SFEU is a Registered Scottish Charity No. SC021876 and a Company Limited by Guarantee No. SC143514 VAT No. 617148346

These support materials were produced with assistance from the European Social Fund.



Energy (Intermediate 2) Domestic Wind Turbines Systems F3FR 11 Introduction These notes are provided to support teachers and lecturers presenting the Scottish Qualifications Authority Course F3FR 11, Energy: Domestic Wind Turbines Systems (Intermediate 2). Copyright for this pack is held by the Scottish Further Education Unit (SFEU). However, teachers and lecturers have permission to use the pack and reproduce items from the pack provided that this is to support teaching and learning processes and that no profit is made from such use. If reproduced in part, the source should be acknowledged. Enquiries relating to this support pack or issues relating to copyright should be addressed to: Marketing Officer - Communications The Scottish Further Education Unit Argyll Court Castle Business Park Stirling FK9 4TY Website: www.sfeu.ac.uk Further information regarding this Unit including Unit Specifications, National Assessment Bank materials, Centre Approval and certification can be obtained from: The Scottish Qualifications Authority Optima Building 58 Robertson Street Glasgow G2 8DQ Website: www.sqa.org.uk



Class Sets Class sets of this pack may be purchased direct from the printer. Costs are dependent on the size of the pack and the number of copies. Please contact: Elanders Hindson Merlin Way New York Business Park North Tyneside NE27 0QG Tel: 0191 280 0400 e-mail: [email protected] Disclaimer Whilst every effort has been made to ensure the accuracy of this support pack, teachers and lecturers should satisfy themselves that the information passed to candidates is accurate and in accordance with the current SQA arrangements documents. SFEU will accept no responsibility for any consequences deriving either directly or indirectly from the use of this pack.



Contents

How to Use this Pack 10

Reference Section 11

What are Skills for Work Courses all about? 12

The Course in Energy (Intermediate 2) 15

Unit Outcomes, PCs and Evidence Requirements 18

Employability Skills Profile 22

Careers Scotland Support 23

Tutor Support Section 24

Introduction 25

Learning and Teaching with Under 16s 26

General Guidance on Unit Delivery 30

Unit Induction 31

Scheme of Work 32

Unit Planner 36

Health and Safety Considerations 42

Signposting of Employability Skills 44

Generating Evidence and Assessment Opportunities for Employability Skills 45

Resources 55

Student Support Section 57

Tutor Note on Student Activities 58

Welcome to Energy: Domestic Wind Turbines Systems 59

Introduction 60

Types of Wind Turbine 64

Up Wind or Down Wind? 65

Vertical Axis 66

Masts and Towers 67

Applications 70

Eigg Community Project 71



Table of Good Practice in Small Wind Turbine Design 72

Tools and Materials 74

Electrical Circuits 82

Simple Construction Projects 86

Cup Anemometer 86

Propeller Type Anemometer 87

Small Wind Turbine Rotor 89

Schematic of small wind turbine system powering a lamp 91

Practical Activities 92

Working in Teams 97

Evaluation 103

Appendix 106

Extension Activities 106

Power in the Wind 107

Wind Speed Measurement 116

The Beaufort Wind Scale 117

Presentation of Wind Data 119

Power Extraction from the Wind Turbine 124

Aerodynamics of Wind Turbines 127

Lift and Drag Forces 129

Power Output 134

Wind/Solar and Biomass Projects 141

Micro-generation Systems 141

Water Pumping 142

Economics of Small Scale Renewable Energy Projects 142

Glossary of Terms 143



How to Use this Pack None of the material in this pack is mandatory. Rather, it is intended as a guide and an aid to delivery of the Unit and aims to provide centres with a flexible set of materials and activities which can be selected, adapted and used in whatever way suits individual circumstances. It may also be a useful supplement to tried and tested materials that you have developed yourself. The pack is available on the SFEU website in Word format to enable you to customise it to suit your own needs. The pack is organised into several sections: The Reference Section provides information on the rationale for, and ethos behind, Skills for Work courses, the course rationale, the Unit Outcomes and evidence requirements and the Employability Skills Profile for Energy (Intermediate 2), showing where the specified employability skills and attitudes can be evidenced and assessed throughout the Course and in this unit. The Tutor Support Section contains a suggested approach to teaching the Unit, advice on learning and teaching with under-16s, guidance on unit induction, unit delivery and advice on integrating the development of employability skills throughout the unit. Finally, this section suggests resources which may be useful for tutors and students. The Student Support Section contains guidance and instruction on: • Background information on renewable energy issues • Information relating to knowledge and understanding of wind turbines • Guidance on activities for Outcomes 1 – 5. Please note that the activities

shown for Outcomes 1 and 2 are intended as practice for the practical assessed elements of the Unit. Detailed guidance on the requirements for assessment will be found in the NAB item for this Unit.

The focus in Outcome 3 is on team work and planning. Guidance and student activities will be found in the Course Guidance and Employability support materials. Extension notes and web-based activities providing more challenging information and tasks where appropriate for the student group are provided in the Appendix. Tutors should be selective in using this material. You may wish to place material from the student notes on your own Intranet by downloading this pack from the Skills for Work section of the SFEU website http://www.sfeu.ac.uk/skills_for_work Activities are identified with the symbol:



Reference Section



What are Skills for Work Courses all about? Skills for Work Courses are designed to help candidates to develop:

• skills and knowledge in a broad vocational area

• Core Skills

• an understanding of the workplace

• positive attitudes to learning

• skills and attitudes for employability. A key feature of these Courses is the emphasis on experiential learning. This means learning through practical experience and learning by reflecting on experience. Learning through practical experience Teaching/learning programmes should include some or all of the following:

• learning in real or simulated workplace settings

• learning through role play activities in vocational contexts

• carrying out case study work

• planning and carrying out practical tasks and assignments. Learning through reflecting at all stages of the experience Teaching/learning programmes should include some or all of the following:

• preparing and planning for the experience

• taking stock throughout the experience - reviewing and adapting as necessary

• reflecting after the activity has been completed - evaluating, self-assessing and identifying learning points.

The Skills for Work Courses are also designed to provide candidates with opportunities for developing Core Skills and enhancing skills and attitudes for employability.



Core Skills The five Core Skills are:

• Communication

• Numeracy

• Information Technology

• Problem Solving

• Working with Others Employability The skills and attitudes for employability, including self-employment, are outlined below:

• generic skills/attitudes valued by employers

• understanding of the workplace and the employee’s responsibilities, for example timekeeping, appearance, customer care

• self-evaluation skills

• positive attitude to learning

• flexible approaches to solving problems

• adaptability and positive attitude to change

• confidence to set goals, reflect and learn from experience.

• specific vocational skills/knowledge

• Course Specifications highlight the links to National Occupational Standards in the vocational area and identify progression opportunities

Opportunities for developing these skills and attitudes are highlighted in each of the Course and Unit Specifications. These opportunities include giving young people direct access to workplace experiences or, through partnership arrangements, providing different learning environments and experiences which simulate aspects of the workplace. These experiences might include visits, visiting speakers, role play and other practical activities.



A Curriculum for Excellence (Scottish Executive 2004) identifies aspirations for every young person. These are that they should become:

• successful learners

• confident individuals

• responsible citizens

• effective contributors. The learning environments, the focus on experiential learning and the opportunities to develop employability and Core Skills in these Courses contribute to meeting these aspirations.



The Course in Energy (Intermediate 2) Course Rationale This Course is intended to equip candidates with the necessary knowledge and skills which will enhance their prospects for employment in the wide range of opportunities within energy sectors. The Course will allow candidates to develop a range of employability skills which are of particular relevance to energy industries. Core Skills of Information Technology and Problem Solving will also be developed throughout the Course where opportunities arise. The Course will offer a variety of approaches to learning and teaching and will include a strong element of experiential learning. It is intended that some of the Course will be delivered and assessed in a different learning environment to that of the school through a partnership arrangement with a college, training provider, or employer. There are many technologies used in the production of energy and this course has been designed to contain both an electrical generation practical/skills element using wind turbines and a heat generation practical/skills element using solar panels. These elements were selected to ensure candidates received a range of skills using different technologies that are involved in the generation of energy. Other systems used to generate energy from both the traditional/conventional and renewable systems will be discussed and evaluated during the Course. The primary target group for this Course is school candidates in S3 and S4. However, the Course is also suitable for S5/S6 candidates and adult candidates who are seeking to enhance their employability and vocational skills in the energy sector. The general aims of the Course are to: • widen participation in vocationally-related learning for 14–16 year olds

• allow candidates to experience vocationally-related learning

• provide candidates with a broad introduction to the energy sector

• allow candidates the opportunity to develop skills relevant to the micro-generation energy sector

• develop the candidates’ engineering skills

• encourage candidates to evaluate the impact of energy generation on the environment

• encourage candidates to foster a good work ethic, including timekeeping, a positive attitude and other relevant employability skills

• provide opportunities to develop a range of Core Skills in a realistic context

• encourage candidates to take charge of their own learning and development

• provide a range of teaching, learning, and assessment styles to motivate candidates to achieve their full potential

• facilitate progression to further education and/or training



In particular, the specific aims of the Course are to: • encourage candidates to consider a career in the energy sector

• develop an awareness of the role of conventional and renewable energy systems in the UK

• develop an awareness of what opportunities there may be within the sector in terms of the types and range of career options

• provide candidates with knowledge and skills which are directly relevant to employment within the energy sector, eg. solar hot water and wind turbines

• provide opportunities for the personal development of skills and attitudes which will improve the candidates’ employment potential within the energy sector

• develop the candidates’ awareness of their individual strengths and weaknesses in relation to the requirements of the sector, and to reflect on how this affects their employability potential

• raise awareness of the impact of the energy sector on the environment

• raise awareness of the responsibilities of the energy industry with regard to the environment

Rationale for Course content The production and use of energy is important in everyone’s life and is also an important area of study and work. It is central to how we reduce our impact on the environment when generating heat or electrical energy or power and to reducing our CO2 emissions which are widely claimed to have an impact on climate change. The generation of energy has traditionally been done through the use of fossil fuels; oil, gas, and coal, with some renewable energy produced from hydro power. Nuclear power was seen, and is still seen by some, as a method of generating energy with zero carbon emissions, but the disposal of the radioactive spent fuel is of major concern and this can counteract the advantages it has with zero carbon emissions. The development of most renewable energy systems is a recent innovation where energy is generated from renewable energy sources, eg. wind, solar, geothermal, bio-fuels, tidal, and wave. These systems have the advantage of generating power with virtually zero carbon emissions. The bio-fuels and geothermal systems can release power on demand, but most of the others depend of sources of energy outwith the control of human beings, and consequently, do not have a constant power output. For example, solar is not effective at night or when it is particularly cold and cloudy; wind is not effective at low wind speeds or very high wind speeds, and while tides are regular, they occur only a few times per week and wind is required to generate waves in our oceans or seas.



The main themes of the course are: conventional energy production, renewable energy production, converting energy from one form to another, industrial or domestic energy generation facilities, practical work with solar panels and wind turbines (integrating team work into the assembly process), and investigating careers within the energy sector. Optional areas covered are the size of an individual’s carbon footprint, oil and gas extraction or conventional energy systems; their contribution to the total energy generated in the UK and their environmental affects. Candidates will study the overall status of energy in Scotland, and in the UK, in general. They will explore the conventional methods of production, including their efficiency levels, various energy conversion principles, and how energy can be conserved. They will also explore the more recent developments in energy production using renewable energy techniques and will develop practical skills in the areas of plumbing, electrical, and mechanical engineering. Careers within the energy sector have been integrated with employability skills which are developed through practical activities. The three optional Units offer different routes for candidates. They can opt for an individual investigation and evaluation of their own carbon footprint, investigate the size of the market segment taken up with conventional production techniques and their sustainability, and explore the use of the national grid as a means of transmitting electricity throughout the UK, or have an in-depth study into the formation and extraction of one type of fuel in its raw state which is particularly relevant to Scotland, ie. offshore oil and gas.



Unit Outcomes, PCs and Evidence Requirements National Unit Specification: statement of standards Unit: Energy: Domestic Wind Turbines Systems (Intermediate 2) Acceptable performance in this Unit will be the satisfactory achievement of the standards set out in this part of the Unit Specification. All sections of the statement of standards are mandatory and cannot be altered without reference to the Scottish Qualifications Authority. Outcome 1 Connect an electrical circuit from a wiring diagram. Performance Criteria a) Appropriate tools are selected for the task. b) Tools and materials are used correctly for the intended purpose. c) All steps to complete the task are followed in the correct sequence. d) Health and safety requirements are adhered to throughout the activity. e) A quality check is carried out on the completed work. Outcome 2 Manufacture a metal part for a wind turbine system from a component drawing. Performance Criteria a) Appropriate tools are selected for the task. b) Tools and materials are used correctly for the intended purpose. c) All steps to complete the task are followed in the correct sequence. d) Health and safety requirements are adhered to throughout the activity. e) A quality check is carried out on the completed work.



Outcome 3 Produce a team plan for the production and testing of a small scale domestic wind turbine system to a given specification. Performance Criteria

a) Contribute constructively to team discussions to establish roles and realistic timescales.

b) Contribute constructively to team discussions on resources. c) Contribute constructively to team discussions on tasks. d) Co-operate with others to finalise a comprehensive plan of roles, resources

required, and tasks set out in sequence. Outcome 4 Contribute as a member of a team to the assembly and testing of a small scale domestic wind turbine system to a given specification. Performance Criteria a) Co-operate with others in the organising, sharing, and safe use of tools and

materials. b) Co-operate with others in maintaining a safe, tidy working area. c) Adhere to the agreed plan and work positively to complete tasks in the agreed

timescale. d) In an agreed role, carry out practical tasks which contribute to the assembly of

the wind turbine system. e) In an agreed role, carry out practical tasks which contribute to the testing of the

system. f) Participate in a quality check of the finished work against the given

specification.

Outcome 5 Evaluate the wind turbine and the team working process. Performance Criteria

a) Evaluate the strengths and weaknesses of the planning, assembly, and testing of the wind turbine.

b) Evaluate the advantages and disadvantages of team working. c) Evaluate own contribution to work of the team. d) Identify action points for improvement in the production of the product and the

team working process.



Evidence Requirements for this Unit Evidence is required to demonstrate that candidates have achieved all Outcomes and Performance Criteria. Performance and written/oral evidence is required for this Unit, the evidence should be gathered at appropriate points throughout the Unit in supervised, open-book conditions, in response to a given brief. Performance evidence — Outcomes 1 and 2 Performance evidence will be generated in response to an assignment consisting of practical activities carried out in supervised workshop conditions. An assessor observation checklist must be completed and signed for each candidate. The practical activities will involve two separate tasks: connecting a wire circuit from a wiring drawing, and manufacturing a metal part for a small scale wind turbine system from a component drawing. In each task, candidates must demonstrate that they can: • select appropriate tools for the task • use tools and materials correctly for the intended purpose • complete all steps for the task in the correct sequence • adhere to health and safety requirements throughout the activity • carry out a quality check on the completed work Performance and product evidence — Outcomes 3 and 4 Performance evidence will be generated in response to a group assignment which will involve the planning, assembly, and testing of a small scale domestic wind turbine system. Practical activities must be carried out in supervised workshop conditions. An assessor observation checklist must be completed and signed for each candidate to confirm achievement. A completed group plan and the finished product should be retained by each group and used by the assessor in discussions with each candidate. The achievement of each candidate is based on his/her individual contribution to the process and not on the final group products. The assessor checklist should be based clearly on the Performance Criteria for Outcomes 3 and 4. Written/oral evidence — Outcome 5 Each candidate must evaluate the effectiveness of the product and process of team working. The evaluation will take the form of a presentation, which could be written, oral, diagrammatical, or electronic. It may be an individual evaluation or a contribution to a group evaluation, provided that all Performance Criteria are met by each candidate. The evidence will be a completed and signed observation checklist for each candidate.



The National Assessment Bank (NAB) pack for this Unit provides candidate review sheets and an investigation brief. Centres wishing to develop their own assessments should refer to the NAB to ensure a comparable standard. NB Centres must refer to the full Unit Specification for detailed

information related to this Unit.



Employability Skills Profile In addition to the specific vocational skills developed and assessed in this Course, employability skills are addressed as detailed in the table below. For the purposes of the table, the Units are referred to as A, B, C and D as indicated. Mandatory Units

Energy: Introduction = A Energy: Domestic Solar Hot Water Systems = B Energy: Domestic Wind Turbine Systems = C Energy: Employability and Careers = D

Optional Units Energy and the Individual = E Energy: Oil/Gas Extraction = F Energy: Conventional Production Technologies and the Grid = G

Employability skill/attitude Evidence

• maintaining good timekeeping and attendance A, B, C, D, E/F/G

• maintaining a tidy work place B, C

• seeking feedback and advice A, B, C, D, E/F/G

• following instructions B, C

• working co-operatively with others A, B, C

• selecting and using tools correctly and for the purpose they were designed

B, C

• using Personal Protective Equipment correctly and working safely

A, B, C

• following basic drawings correctly B, C

• checking quality of work A, B, C, D, E/F/G

• working to agreed deadlines A, B, C, D, E/F/G

• organising work effectively A, B, C, D, E/F/G

• working confidently A, B, C, D, E/F/G

• willingness to learn new skills or techniques B, C

• working independently A, B, C, D, E/F/G

• reflecting on own performance B, C

• learning from past experiences B, C

• awareness of a range of careers and job roles D

• developing investigation skills A, D, E/F/G

• developing presentation skills A, B, C, D, E/F/G

• developing creativity skills A, B, C, D, E/F/G



Careers Scotland Support for School/College Collaboration for Scotland’s Colleges in the Scottish Enterprise area Since August 2006 Careers Scotland (SE and HI areas) has been funded by the Scottish Government to support College/School Collaboration and encourage and promote vocational educational choices for pupils in schools. Careers Scotland (now part of Skills Development Scotland) has an important role to play in selection, recruitment and pre-entry career guidance, as well as ongoing support and pre-exit career guidance, to ensure the pupils’ experience of SfW is capitalised upon in any future career planning. Careers Scotland activity takes place locally and nationally under 4 objectives: • Providing careers advice, guidance and employability support to pupils and

their parents pre, during and post vocational education experience, focusing primarily but not exclusively on SfW pupils - demonstrating how these educational choices have implications for future career options, and support the achievement of future career goals and supporting effective transitions

• Providing targeted support to pupils at risk of becoming unemployed who would benefit from undertaking a vocational course

• Partnership working to ensure vocational study is given parity of esteem with other school and post school options, focusing on recruitment / selection and retention of pupils on vocational courses

• Capacity building through relevant shared CPD events and resource development to increase understanding of the process of uptake of vocational options and facilitate more effective support to pupils navigating these options

For further information on Careers Scotland (SE)’s involvement in school/college collaboration locally, please get in touch with your Careers Scotland Regional contact: South East (Edinburgh & Lothians; Forth Valley; Borders) Stephen Benwell 01786 452043 [email protected] North East (Tayside; Grampian; Fife) Val Ormiston 01592-631155 [email protected] South West (Dumfries & Galloway; Ayrshire; Lanarkshire) Jean Geddes 01698 742192 [email protected] West (Glasgow; Dunbartonshire; Renfrewshire) Sandra Cheyne 0141 242 8338 [email protected]



Tutor Support Section



Introduction The main purpose of this Unit is to: • Provide a general background to the operation and applications of small

domestic wind turbines. • Describe the different kinds of wind turbines available and discuss the

advantages and disadvantages of each type. • Describe the various methods of controlling the speed and power output of

small wind turbines. • Enable students to select and use the basic tools and materials in the

construction of small domestic wind turbines. • Contribute in a team in planning and assembling a small wind turbine system. • Review and evaluate own performance. Students will learn terminology and skills during the process of the practical work. They will also develop work practices and attitudes that will enhance their employability skills. The need to promote safe working practices in the workplace with respect to industry is paramount at all times. Safe working practices should include: • keeping the workplace tidy and free from obstruction

• maintaining good working relationships with others

• maintaining a positive attitude to instruction

• using tools for their intended use only

• using tools correctly

• wearing the relevant Personal Protective Equipment (PPE) The Outcomes in this Unit are practical and students should be given plenty of opportunities to handle and work with tools and equipment relevant to the Domestic Wind Turbine Systems. A key aspect of the practical activities is the development of student confidence therefore students should be given adequate support in all stages of practical work. Extension Activities Extension notes and web-based activities providing more challenging information and opportunities to investigate and analyse further information on wind turbines where appropriate for the student group are provided in the Appendix. Tutors should be selective in using this material.



Learning and Teaching with Under 16s Scotland’s Colleges have made significant progress in meeting the needs of young learners. Our knowledge of the learning process has increased significantly and provides a range of strategies and approaches which gives us a clear steer on how lecturers can add to their skill repertoire. Lecturers can, and do, provide a stable learning environment where young students develop a sense of self-respect, learn from appropriate role models and see an opportunity to progress. There are basic enabling skills for practical application which can further develop the learning process for this group of students. So what are the characteristics of effective learning and teaching which will help to engage young learners? Ten ways to improve the learning process for under 16s (This list is not exhaustive!) 1. Activate prior knowledge and learning – ascertain what the learner knows

already and teach accordingly. Young people do have life experience but it is more limited than adult learners and they may not always be aware of how it will assist them in their current learning.

Tips - Question and answer; Quick Quiz; Quick diagnostic assessment on computer; present key words from the course or unit and see how many they recognise or know something about.

2. Tune learners into the Big Picture – the tutor knows the curriculum inside out and why each lesson follows a sequence, however the young learner does not have this information and is re-assured by being given the Big Picture.

Tips – Mind map or concept map; use visuals, for example wall displays of diagrams, photographs, flow charts; explain the learning outcomes in language they will understand; We Are Learning Today (WALT) targets and What I’m Looking For (WILF) targets; give clear and visible success criteria for tasks.

3. Use Advance Organisers – these are lists of the key concept words that are

part of the course or unit.

Tip – Highlight on any text the concept words that you will be using; make a visible list and put it on display – concept words can be struck off or referred to as they occur (NB this helps with spelling and independent learning as they do not have to keep checking meaning); highlight essential learning and action points.

4. Vary the teaching approaches. The two main approaches are instructing and demonstrating, however try to provide opportunities to facilitate learning.

Tips – Ask students what they know now that they did not know before, or what they can do now they could not do before, at appropriate points in the lesson or teaching block; ensure there are problem solving activities that can be done individually or in groups; ask students to demonstrate what they have



learned; use a range of question and answer techniques that allow participation and dialogue, eg. provide hints and cues so that they can arrive at answers themselves.

5. Preview and review of learning. This helps to embed previous learning and listening skills and provides another opportunity to elicit learner understanding. Consolidates and reinforces learning.

Tips – At the beginning of each lesson, or session, review previous learning and preview what is coming up; at the end of each lesson or session, review what has taken place and what will be focussed on next time – these can both be done through question and answer, quizzes and mind mapping activities.

6. Language in the learning environment. Do not assume that the language which is used in the learning environment is always understood by young learners, some words may be familiar but do not have the same meaning when used vocationally.

Tips - At appropriate points ask students what words mean; explore the various meanings of words to find out if they may have come across this language in another context; by looking at the structure and meaning of words there is an opportunity for dialogue about learning and to build vocabulary.

7. Giving instructions in the learning environment. This is one of the most difficult tasks a tutor has to do whatever the curriculum area. With young learners this may have to be repeated several times.

Tips – Ask a student to repeat back what you have asked them to do before beginning a task; ask them to explain the task to one of their peers; use the KISS principle – Keep It Short and Simple so that they can absorb and process the information.

8. Effective feedback. Feedback is very important for the learner to assess their progress and to see how and what they can improve. Provide opportunities to engage in dialogue about the learning function of assessment – provide details of the learner’s strengths and development needs either in written or spoken form. With younger learners identifying one or two areas for development is sufficient along with acknowledgement of what has been done well.

Essentially, learners are helped by being given a specific explanation of how work can be improved. You can also use summative assessment formatively, ie. as an opportunity to identify strengths, development needs and how to improve.

Tips – Ask students themselves to identify their own strengths and development needs – self evaluation; peer evaluation of work can be successful once they have been taught how to do it; the tutor can produce a piece of work and ask students to assess it anonymously; have a discussion about the success criteria for the task and ensure the students are clear about



them; allow learners to set criteria for success and then measure their achievements against these.

9. Managing the learning behaviour. Under 16s are coming into Scotland’s Colleges and training establishments from largely structured and routine-driven environments in schools and early feedback from those undertaking Skills for Work courses indicates that they very much enjoy the different learning environment that colleges and other training providers offer. Remember though that these are still young learners. They will still expect tutors to provide structure and routine, and will perform best in a calm, orderly learning environment. Young students will respond to firm, fair, and consistent management. Such routines have to be established quickly and constantly reinforced.

Tips - Health and safety is non-negotiable and consequences of non-compliance with the regulations should be made clear and adhered to at all times; set out your expectations from day one and provide a consistent message; have clear beginnings, middles and endings for each session; be a positive role model for your students, ie. be there before they are and manage the learners with respect; always deliver what you promise; build up good relationships and get to know the learners, make the curriculum interesting and stress the relevance of the learning; set up a positive behaviour management system. By following these guidelines you will build up two-way respect, which, while sometimes challenging to achieve, can be very powerful and work to everyone’s benefit.

10. Care and welfare issues. School/college partnerships mean increasing numbers of young learners in college. Tutors have to be aware of their professional responsibilities and mindful of young people’s rights. However tutors have rights too, in terms of feeling safe and secure in working with young people and there are basic steps staff can take to minimise risks. It is essential that colleges ensure that tutors have a working knowledge of the Child Protection policies (local authority and college documentation) and follow procedures and policies diligently. School/College Liaison Officers will be familiar with these documents and can provide support and advice. There are also training sessions on Child Protection available from SFEU (see the following page).

Tips - Avoid one-to-one situations with young students in a closed area; do not do or say anything that could be misinterpreted; if the opportunity arises, do some observation in schools to see and discuss how teachers use the guidelines for their own protection as well as the young person’s.

Most young people are a delight to work with and they will positively enjoy the experience of learning in college. However, there will inevitably be some who are disengaged, disaffected and who have not yet had an opportunity to experience success. ‘Skills for Work’ is a unique educational initiative that young people can be motivated to buy into – you as the tutor are key to the success of these programmes.



Skills for Work Workshops To take this 10 point plan forward and to add to it, you can attend one of SFEU’s ‘Get Skilled Up’ half day workshops for tutors delivering Skills for Work Courses, when we explore further the learning process and look at a range of specific teaching and learning techniques to use with the under 16 age group. To find out when the next event is visit our website www.sfeu.ac.uk or contact the Learning Process team at SFEU on 01786 892000. Child Protection Workshops These are run on a regular basis by staff at SFEU in Stirling and also in colleges. For more information on these workshops please contact members of the Access and Inclusion team at www.sfeu.ac.uk or contact the team at SFEU on 01786 892000.



General Guidance on Unit Delivery The emphasis in this unit is on a practical approach in which the students complete practical tasks and activities. The unit is also designed to focus on the employability skills that employers value. The students should be given handout notes on the different kinds of wind turbines and should read the material on wind turbine operation. Once they are familiar with the concepts they should then be given the opportunity to research some of the suggested websites to see examples of wind turbine practice and the terminology and key parameters involved in their operation. Students can also study the more advanced Student Notes at the end of the Student Support Section and try the calculations. There are opportunities to connect up an electrical circuit and manufacture the tail vane for a small wind turbine. The students will participate in a team project to assemble and test a small wind power system. As students progress through the practical activities, it is envisaged that opportunities will arise to discuss employability skills development and perhaps subsequent career paths. Associated knowledge and skills to be developed include: • safe working practices • comprehension of information from simple drawings • commonly used terminology. The Unit could be integrated for delivery with other units of the course and if this is the case this support pack should be used in conjunction with that of other units. The unit is also an ideal opportunity to progress Core Skills within the context of Mechanical and Fabrication. Numeracy Skills: in the form of measuring and cutting material. Working with Others: is a valid and inherent skill in any workplace or workshop, and students should be actively encouraged to seek advice from their tutor and work with their peers as part of a team. Problem Solving: engineering is beset with problems and trades people are faced on a daily basis with problems that require efficient and cost effective solutions. Communication: part and parcel of the engineer’s working life is communication, whether it be taking in oral or written instructions, interpretation of drawings,



interpretation of manufacturers’ manuals, making an oral presentation or simply giving instructions to others. IT: is linked to all of the above. Most engineers use IT to aid numeracy skills, to communicate and to problem solve. IT is widely used to present and record information and to provide graphic communication for engineers. The Internet is a valuable resource to enable students to seek additional information about tools and processes. Unit Induction Although the Unit will have been outlined at the course induction it is vitally important to include an induction to the Unit. The students need to know what exactly the unit is about, what they will accomplish and achieve the outcomes and, just as important, what is expected of them. The overall practical construction aspect of the course and unit will need to be reinforced. It should be stressed at unit induction that the skills valued by employers such as timekeeping, attendance etc will be monitored and recorded and that all students will be encouraged to show a positive attitude. The short time spent on Unit induction will pay dividends later in the Unit. Unit induction can start with an outline of the Unit content – what they’re going to be doing - some discussion about small wind turbines and some practical work - students will want to get stuck into the fun part as soon as they possibly can. A fun resource which will also give them the basics of wind turbines in a cartoon style crash course can be found on this website:

http://www.windpower.org/en/kids/

Induction could also include: • your plans for teaching the Unit – how they’ll be learning the practical skills

• assessment methods and schedule

• where employability fits in – start by asking them what they think!

• a briefing on health and safety

• the importance of regular attendance and good timekeeping to encourage employability skills development - get them into good habits just as if they were at work and in employment!

• you might also think about inviting an engineer or engineering apprentice from the wind turbine industry to speak to the class about their work, about job prospects in this area of the engineering industry and to reinforce the value that employers put on employability skills.



Scheme of Work The Outcomes should to be taught in the order listed in the Unit. The review and evaluation of employability skills should be integrated in all the activities undertaken in the unit. At the beginning and throughout Outcomes 1, 2 and 3 of the Unit the following should be emphasised and adhered to: Safe Working Practices in the Workshop The Care and Use of PPE

• workshop safe working practices

• workshop housekeeping

• health and safety

• accident procedures

• fire alarm procedures

• footwear

• overalls

• eye protection

• hand protection

• gloves

A suggested time allocation for the unit is:

Unit Induction Identify the main components of a small domestic wind turbine system

5 hours

Connect up an electrical circuit and manufacture a tail vane for a small wind turbine

15 hours

Contribute to a team in the planning, assembly and testing of a small scale domestic wind turbine system to a given specification

15 hours

Remediation Review and evaluate own performance in relation to identified employability kills

5 hours

Because it is important to ensure that students understand the theory behind the practical sessions the above schedule includes some time for class discussion and background reading.



Outcomes 1 and 2 (approximately 20 hours) Connect an electrical circuit from a wiring diagram and manufacture a tail vane for a small wind turbine Unit Induction Identify the main components of a small domestic wind turbine system

• Tutor input on underpinning knowledge. Student investigation.

Appropriate tools and materials are selected for the task

• health and safety, safe working practices and employability

• safety instructions

• tools and materials selection

Tools and materials are used correctly for the intended purpose

• health and safety, safe working practices relating to the handling and use of tools

• allow students to practise tool usage on simple tasks

All steps to complete the task are followed in the correct sequence

• establish tasks to be done and their correct sequence

Health and safety requirements are adhered to throughout the activity

• risk assessment of electrical exercises

• adherence to health and safety requirements in the workshop

• connect electrical circuit A quality check is carried out on the completed work

• conduct quality checks using pro forma worksheet

Outcomes 3 and 4 (approximately 15 hours) Produce a team plan for the production and testing of a small scale domestic wind turbine system to a given specification. Contribute as a member of a team to the assembly and testing of a small scale domestic wind turbine system to a given specification. Planning stage Contribute constructively to team discussions to establish roles and realistic timescales

• identify and establish the types and nature of team roles as part of a team

• agree individual team roles

• identify and quantify agreed project timescales as part of a team



Contribute constructively to team discussions on resources

• interpret the given specification and drawings for a domestic wind turbine system

• identify and establish resource requirements as part of a team

Contribute constructively to team discussions on tasks

• identify and establish tasks as part of a team

• identify and agree task sequence as part of a team

Co-operate with others to finalise a comprehensive plan of roles, resources required and tasks

• compile and agree a team plan of roles, resources, tasks and task sequence for the assembly and testing of a domestic wind turbine system

Assembly and Testing Stage Cooperate with others in the organising, sharing and safe use of tools and materials

• sourcing and use of tools in a correct and safe manner using tools solely for the purpose for which they are designed

• wearing appropriate PPE

• preparing appropriately to carry out tasks.

Cooperate with others in maintaining a safe, tidy working area

• maintaining a tidy workplace

• showing health and safety awareness

Adhere to the agreed plan and work positively to compete tasks in the agreed timescale

• maintaining good attendance

• maintaining good timekeeping

• adhering to team plan

• completing tasks to agreed timescales

In an agreed role, carry out practical tasks

• adhering to agreed team roles

• adhering to specification

• carrying out tasks to assemble of a domestic wind turbine system

In an agreed role, carry out practical tasks which contribute to the testing of the system

• carrying out tasks to test a domestic wind turbine system



Participate in a quality check of the finished work against the given specification

• carrying out a quality check on the domestic wind turbine system against the specification

Outcome 5 (approximately 5 hours) Evaluate the wind turbine and the team working process Evaluate the strengths and weaknesses of the planning, assembly and testing of the wind turbine

• team evaluation and recording of what went well, what did not go well in the planning phase of the project

• team evaluation and recording of what went well, what did not go well in the assembly phase of the project

• team evaluation and recording of what went well, what did not go well in the testing phase of the project

Evaluate the advantages and disadvantages of team working

• evaluate and record the advantages of the team working - what went well, what did not go well

• evaluate and record the disadvantages of the team working - what went well, what did not go well

Evaluate own contribution to work of the team discussions

• individual evaluation and recording of what went well, what did not go well during team discussions

Identify action points for improvements in the production of the product and the team working process

• team identification of action points for improvements in the production of the product

• team identification of action points for improvements in the team working process

• individual/team presentation of action points



Unit Planner The following Unit planner is intended as a guide only to how centres might go about delivering the unit and what it covers. Each practical session should start with the health and safety requirements that will be applicable to that particular lesson and any additional PPE that might be required. The Unit planner is based around the production of a simple Domestic Wind Turbine System. During the practical activities, the use of tools and equipment for assembly and testing of a domestic hot water system will provide opportunities to discuss the varying roles and responsibilities within the energy industry. This could include the tools and practices used by local energy firms. Activities – refers to the named activity found in the Student Support Section or, where indicated, in the NAB for the Unit. Practical Tips

It is expected that as each basic practical skill is demonstrated that good practice will be emphasised, and that any good trade specific hints or tips are also included in the lesson. It is also recommended that some or all of the following should be integrated with the range of practical activities: • The use of employed apprentices attending college to aid workshop sessions

• The use of various speakers/experts/tradespersons to aid employability skills and knowledge of local industry

• The use of ICT if appropriate

• The use of energy websites images and videos



Outcomes 1 and 2 Connect an electrical circuit from wiring diagram Manufacture a metal part for a wind turbine system from a component drawing Objectives: • Safe working practices, health and safety requirements and employability – to

establish a level of knowledge and understanding of health and safety and employability.

• Identify and select and use appropriate tools and materials

• Identify and follow the correct sequence of tasks

• Connect electrical circuit

• Manufacture a metal part

• Carry out a quality check Resources: • Circuit diagrams and component drawings • Student Support Materials • Tools and materials Learning and teaching process: • use group discussion to determine the level of student knowledge of health

and safety issues; develop this to discuss the need for general health and safety in the workshop environment; emphasise the student’s own health and safety and that of others in the workplace in order to create a safe learning environment for everyone. Use this opportunity to promote awareness of employability skills such as attendance, punctuality and especially behaviour in relation to safety requirements.

• using the circuit diagrams form small group discussions relating to a simple risk assessment ie. identifying hazards, persons at risk, risk, risk rating (low/medium/high), existing control measures and any action required.

• discussion and selection of tools • allow students to practise tool usage on simple tasks • correct sequence of tasks is established • practical exercises • students carry out a quality check on completed products Activities • Outcome 1 Practical • Outcome 2 Practical



Outcome 3 Produce a team plan for the production and testing of a small scale domestic wind turbine system to a given specification Objectives: • Identify and establish team roles and timescales as part of a team

• Identify and establish resource requirements as part of a team

• Identify and establish tasks as part of a team

• Identify and establish task sequence as part of a team

• Compile a plan of roles, resources, tasks and sequence Resources: • Specification and drawings • Student Support Materials Learning and teaching process: • use group discussion to highlight the types and the benefits of allocating team

roles.

• state and demonstrate correct methods/techniques of identifying resource, task requirements and task sequence

• use teams to agree and compile plan of roles, resources, tasks. • use teams to agree sequence of tasks Activities • Outcome 3 Practical • Identify, establish and agree team roles • Instrument of Assessment 3 – Specification and Outline Plan (See NAB) • Instrument of Assessment 3 – Scheduled Plan (See NAB)

5,11,13



Outcome 4 Contribute as a member of a team to the assembly and testing of a small scale domestic wind turbine system to a given specification Objectives: • Safe working practices co-operating with others in the sharing and safe use of

tools and materials in a maintained safe working environment

• Correct adherence to agreed team plan and timescales

• Correct method of assembly of a wind turbine within an agreed team role

• Correct method of testing of a wind turbine system within an agreed team role

• Carry out a quality check of completed work against the given specification Resources: • PPE • Specification and drawings • Student Support Materials • Tools and materials Learning and teaching process: • use group discussion to emphasise the need to follow safety instructions and

maintaining a safe tidy working area

• state and demonstrate correct methods/techniques of assembly of a wind turbine system

• correct assessment of the functionality and testing of a wind turbine system • carry out a quality check of completed product Activities

• Instrument of Assessment 3 - Specification (See NAB) • Instrument of Assessment 4 - Teamwork exercise (See NAB)



Outcome 5 Evaluate the wind turbine system and the team working process Objectives: • Evaluate the strengths and weaknesses of the planning, assembly and testing

of the wind turbine

• Evaluate the advantages and disadvantages of team working

• Evaluate own contribution to work of the team

• Identify action points for the improvement in the production of the wind turbine

• Identify action points for improvement in the team working process Resources: • Student Support Section Materials Learning and teaching process: • use group discussion to emphasise the need for critical evaluation

• use group/teams for general discussion on the importance of creating action points for improvement

• individuals/teams to give a presentation on the evaluation of wind turbines and

the team working process Activities • Instrument of Assessment 5 – Team Worksheet 1 (See NAB) • Instrument of Assessment 5 – Team Worksheet 2 (See NAB) • Instrument of Assessment 5 – Team Worksheet 3 (See NAB) • Instrument of Assessment 5 – Team Worksheet 4 (See NAB) • Project Presentation



Practical Activity Checklist Checklist to monitor the progress of each student’s completion of the Outcomes.

Student Name Outcome 1 Outcome 2 Outcome 3 Outcome 4 Outcome 5



Health and Safety Considerations Safe working techniques will include general workshop behaviour and protocol. This will include the correct handling and transportation of tools: tool safety; workshop layout; and procedures for starting and finishing practical activities. First Aid considerations should include awareness of the nearest first aid station, first aider, first aid procedures, accident and ‘near miss’ reporting, and avoidance of potential accidents. Fire Alarm evacuation procedures should be practised and students made familiar with the audible warning sound, alarm points, location of fire fighting equipment, fire exits, assembly areas and correct conduct under alarm conditions. The Control of Substances Hazardous to Health (COSHH) must be stressed if students are subjected or exposed to any chemicals, fumes, dust or irritants. Good housekeeping is the welfare of all participants and the general working conditions in the workplace. This will include safety, PPE, behaviour, conduct, storage and condition of tools and equipment, walkways and handling and disposal of waste oil and scrap materials. Whilst the tasks may not always require the movement or handling of heavy objects, the use of safety footwear and manual handling techniques should be discussed and encouraged as a matter of good safety practice. Some tasks may require using heat or a heat source and students should be made aware of the dangers of both hot and previously heated materials and workbenches. Personal Safety The students need to appreciate that they are responsible for their own safety and the safety of others. This will include their conduct and behaviour in all activities. Safe working practices in workshops and the safe use of tools and equipment should be emphasised. In all the activities students are asked to perform they should be encouraged to make sound judgements on issues such as: • the effect of their actions on fellow students

• are the tools and equipment in good usable condition?

• are they being asked to carry out an action they are unfamiliar with?

• should they seek advice from an appropriate person? Students’ personal dress should be hardwearing and give protection against grease/oil/heat etc. This clothing should not have any loose sleeves.



Students should be dissuaded from wearing sports trousers and tops as these items are nearly always manufactured from plastic materials and are not suitable for engineering workshop use. No jewellery of any form should be worn and neither should any piercings be worn. At the beginning of the unit and prior to each practical session the following should be emphasised and adhered to: Safe Working Practices in the Workshop The Care and Use of PPE

• workshop safe working practices

• workshop housekeeping

• health and safety

• accident procedures

• fire alarm procedures

• footwear

• overalls

• eye protection

• hand protection

• gloves

Students need to understand their roles and responsibilities in relation to health and safety. Students may already have an appreciation of health and safety issues in one of the other course units but it should be emphasised to them that in this unit they may be dealing with a different set of potential hazards and that each practical activity will probably start and end with health and safety issues relevant to the practical skills covered in the lesson.

Further information on Health and Safety can be found in the Energy: Course Guidance and Employability Skills support pack.



Signposting of Employability Skills In addition to the specific vocational skills developed in this Unit, students will have opportunities to develop and apply their knowledge and understanding of the employability skills. Throughout the pack there are numbered flags like the one shown here, showing which specific employability skill can be highlighted and/or assessment evidence recorded when students are busy with the various activities in the Unit.

1 Maintaining good timekeeping and attendance *

8 Following basic drawings correctly* 15 Reflecting on own

performance *

2 Maintaining a tidy workplace* 9 Checking quality of

work* 16 Learning from past experiences *

3 Seeking feedback and advice* 10 Working to agreed

deadlines* 17 Awareness of a range of careers and job roles

4 Following instructions* 11 Organising work

effectively * 18 Developing investigation skills

5 Work cooperatively with others* 12 Working

confidently* 19 Developing presentation skills*

6

Selecting and using tools correctly and for the purpose they were designed*

13 Willingness to learn new skills or techniques*

20 Developing creativity skills*

7

Using Personal Protective Equipment correctly and working safely*

14 Working independently*

* The employability skills marked with an asterisk* are directly assessed in this Unit.

1, 5, 6, 7



Generating Evidence and Assessment Opportunities for Employability Skills The unit is designed to give the students the technical knowledge, skills and understanding of Domestic Wind Turbines Systems but as instances arise naturally within the completion of practical work or activities, job roles and career paths may be discussed so that all students are aware of progressions within the energy sector. These discussions will also encourage an interest in energy in general. It is important in that the students develop the ability to reflect on how they performed in the completion of tasks. In the context of the Domestic Wind Turbines Systems unit this will involve reflection on the development of both practical and employability skills. The skill of evaluation lets the candidates analyse what they did well, what they did not do so well and how they can improve. This means they will develop an awareness of their individual strengths and weaknesses. The unit also encourages the students to apply new skills, knowledge and understanding of energy in the completion of practical assignments by using skills of evaluation and problem-solving in a vocational context. It is strongly advised that course teams meet together to discuss and agree a co-ordinated approach to the teaching and developing of the employability skills throughout the Course and to ensure that the team has a common interpretation of the skills and attitudes. You will find or create countless opportunities to help students develop their employability skills. The following pages show some ways of going about it to get you thinking!



Generating Evidence and Assessment Opportunities for Employability Skills Employability Skills

Delivery Advice

Possible Activities/Contexts

Maintaining good timekeeping and attendance

• Good timekeeping and attendance is relevant throughout the Course. • Discuss the importance of good timekeeping within the energy sector and

get students to assess their past timekeeping record. They should identify what improvements, if any, are needed. This should take place at the start of the Course and will set the expected standards.

• Staff should make their expectations clear right from the start of the course or Unit.

• A good initial activity is to have the students write the class guidelines themselves by identifying pros and cons of good and poor attendance and timekeeping – the benefits in the workplace of one and the consequences of the other.

• These guidelines or ground rules can be posted in the workshops and classes and referred to on a regular basis.

• Relate the ground rules to the world of work, eg. arrive on time, back from breaks on time etc. The measure of a student’s success in this aspect is for them to be honest in their appraisal of their performance and in making progress. ‘Distance travelled’ should be adopted, rather than a particular minimum percentage of classes attended.

• Attendance and timekeeping should be monitored throughout the Course. Students should be given feedback on their performance – both good and bad – in this regard. If you take note of patterns of performance it should be easy to give the students accurate feedback.

• Turning up for classes on time

• Returning from breaks on time

• Arriving on time to visits

• Sticking to planned work schedules regarding timing of activities

• Staying in class for the duration of the planned activity (no extended toilet breaks)

1



Maintaining a tidy work place

• Discuss the need to keep a tidy work area or workspace from a Health and Safety and a ‘personal organisation’ point of view.

• Educate the class to keep the work area tidy at all times. • Allow them to reason for themselves about the potential

consequences of an untidy work area! • Perhaps one at a time, in pairs, or in small teams the students could

be on ‘tidy up’ duty. • Emphasise to the class that this is often the routine in the actual

workplace. • If students get into a good routine with this it should be only on rare

occasions that you have to pull them up on their tidiness. • If the workplace is clean at the start of the lesson then the workplace

should be left in the same clean state for the next class.

• Tidying workspace, generally as the • work proceeds • Clean and store tools correctly • Clean workbenches • Keep walkways clear and clean • Disposal of scrap material into the • proper bin • Tidying up after a specific spill of

materials

Seeking feedback and advice

• Seeking feedback and advice from teaching staff is relevant to all Units in the Course.

• Discuss the benefits that getting feedback from staff and asking for advice. This can increase the students’ level of confidence in what they are doing and can reinforce their views of the direction they are taking. Success can be greatly increased by using knowledge and experience gained from others.

• Young students can be wary of seeking advice for fear of highlighting their own lack of understanding or of being singled out for ridicule perhaps based on past experience.

• Staff should emphasise that in the workplace it is essential that they seek advice if they are not sure about something as the consequences of not doing so could be quite serious eg. misusing tools, poor

• Ask questions • Check work progress with staff • Check tool safety with staff • Seek tutor feedback • Confirm instructions when unsure

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techniques can result in injury. • Students should be praised for seeking advice and reassured that staff

welcome their questions and it also helps them to demonstrate another employability skill: positive attitude to learning.

• Tutors should explain that they may not be able to give advice or help straight away (as they may be helping somebody else) but they will respond as soon as they can.

Following instructions

• Discuss the benefits of following instructions, from regulations that are mandatory to class or work processes that have been devised by experienced staff. Include the pitfalls of doing their ‘own thing’.

• It can be difficult to keep the attention of under-16s. When you want them to cultivate the skill of following instructions it’s important to transmit the instructions clearly and concisely.

• Trying to get students to think of the reason behind an instruction can help them to remember it.

• Get them to repeat the instruction or explain it in their own words to make sure they’ve understood and know what’s required.

• If an individual student is struggling with an aspect of their work they may appreciate personal assistance and quiet one-to-one instruction. This would be an opportunity for you to note their positive response to any instructions you give them at that time.

• Health and Safety procedures • Work schedule or sequence • Practical work and trade techniques • Checking quality • Planning and preparation

4



Working co-operatively with others

Team working is a mandatory part this Unit. • Discuss the advantages and disadvantages of working in a team, eg.

advantages could include sharing of workload, support from each other, generating more ideas; the disadvantages could be that a consensus is needed on all points and the uneven workloads that can be put on team members sometimes.

• Working co-operatively with others (sometimes referred to as Working With Others) is mainly about communication and taking others into consideration.

• Get the class into the habit of working as a team where appropriate eg. when tidying up during and at the end of practical sessions.

• Get them to speak to each other – and to you – about the sharing of workspace, tools, equipment and materials.

• Monitor the teams as they assemble and test the wind turbine system. • Watch out for specific instances of the students working co-operatively

together – including demonstrating a specific awareness of health and safety issues. You should note this evidence.

• Identify the roles undertaken by team members and discuss how these roles were allocated.

• Mixing different school groups will help to reinforce the idea of working cooperatively with everyone in the workplace – not just friends.

• Assembly and test of wind turbine • Social interaction • Students working in harmony • Sharing of experiences • Peer support

Selecting and

• Discuss the need to select the right tool for the job and why it must only be used for the purpose for which it was designed.

• The sourcing of tools means that each centre must inform the students of the procedures to be followed for the acquisition of tools and equipment.

• Tool acquisition procedures followed during practical workshop sessions

• Correct number of tools used • Carrying tools safely

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using tools correctly and for the purpose they were designed

• The correct use of tools must be demonstrated before students are allowed to practise the skill.

• Movement of tools to be completed in a safe manner. • Each tool has a function that it was designed for and use or misuse of

the tool for any other task/purpose should be discouraged. The dangers of misuse of tools must be stressed.

• Students should be encouraged to report any faulty or worn tools. • Each tool must be clean and free from defects at the start of the

practical activities and at the end. • Students must be made aware that if a tool is worn or becomes

unusable that they are responsible for reporting the fault. • Tools should always be returned to their proper storage place.

• Using tools safely • Clean and store tools safely and

correctly • No tools left out at end of session

Using Personal Protective Equipment correctly and working safely

Health and Safety is important to employers and is a key part of the learning and teaching of each of the practical based Units.

• Discuss the role of Health and Safety in the workplace and the use of

Personal Protective Equipment (PPE) to reduce the chance of injury. The requirements and the role of students and staff should be made clear.

• From the first workshop session to the last there should be ample opportunity to collect evidence of health and safety issues.

• Discussion on what PPE might be required for specific tasks and the importance of PPE in the protection of everyone.

• Induction procedure • Behaviour in workshop • Routinely wearing PPE • Wearing correct PPE • Cleanliness • Clear walkways • Manual handling • First aid procedures • Fire procedures • Tool and equipment safety • Personal hygiene • Identification of hazards by

students. • First aid and fire awareness.

7



Following basic drawings correctly

• Following basic drawings correctly is an essential aspect of this unit. • Discuss the role of drawings in communication and the need to be

able to extract relevant information from them. • Students should be issued with drawings and sketches for all practical

activities. • Using drawings as a means of communication. • Correct interpretation reinforced.

• Reading drawings • Carrying out quality checks • Planning sheets • Following instructions in the correct

sequence

Checking quality of work

• Discuss how the checking of their tasks can lead to a higher quality of

work and hence meet the standards required. • Students constantly check against the drawings for dimensions,

materials, fits and sequence of operations. • Students should be made aware of acceptable standards in terms of

the quality of practical, investigative and presentation work.

• Quality checking as work progresses

• Quality checking at the end of practical activities

• Quality checking at the end of non-practical work

• Checking and reporting on fitness for purpose

Working to agreed deadlines

• Discuss the need to keep to deadlines and the effects that can result if they are not maintained. Demonstrate the importance in the real world of keeping to deadlines eg. industry employs project managers whose main role is to keep work on schedule.

• Students made aware of the benefits of keeping to deadlines and of the possible consequences of work going beyond deadlines.

• Staff discuss with students their progress and ability to meet the deadlines.

• Checking progress against deadlines

• Be aware of time remaining until deadlines

• Plan work schedule to meet deadlines

10

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Organising work effectively

• Discuss how organising and planning work leads to a greater chance of meeting deadlines and meeting quality standards. Staff should emphasis a logical approach to organising work where any process is a combination of smaller steps taken one at a time.

• This will help the students develop their organisational and planning skills.

• Creating work schedules • Monitoring progress against

schedules

Working confidently

• Discuss the benefits that working confidently can give eg. being able to ask questions or give their point of view without the fear of feeling stupid, being able to stand up in front of others and give a presentation, to work without constantly needing reassurance.

• Students will have the opportunity to working confidently as they perform practical tasks.

• Carrying out practical tasks • Leading a group • Drawing up work schedules • Discussions with staff and peers

Willingness to learn new skills or techniques

• Discuss the benefits of learning new skills and how this is essential in a constantly changing world to keep your job or gain promotion.

• New skills and techniques will be acquired during the practical tasks. • A positive attitude to learning can be stimulated by the enthusiasm

and expert knowledge of the staff member. • Introduce practical activities very early on. • Interesting tasks and the assembly and testing of the wind turbine

system will be enjoyed and will help with attention, following instructions, asking questions, taking advice, carrying out quality checks and a desire to learn more.

• Listen to instructions • Applying feedback • Asking questions • Practising skills • Discussions with tutor • Checking quality • Assisting others • Genuine participation in review

process • Perseverance • All of the other employability skills

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Working independently

• Discuss the advantages and disadvantages of working individually, eg. advantages could include taking full responsibility, having complete ownership and not depending on others, to disadvantages such as not being able to share problems with others and having little social interaction.

• Individual activities and research • Discussions with tutor • Checking quality • Self evaluation

Reflecting on own performance

• Discuss how self reflection can lead to improvements in the work they are doing and in life in general.

• Students often find reflecting and evaluating quite difficult. The use of appropriate questions can aid this process. Reasonable time needs to be allocated to teaching these skills and provide plenty of opportunities for development.

• Getting the students to complete a reflective diary (not assessed) will help them to develop this skill on a regular basis.

• After practical tasks • After assembly tasks • After testing

Learning from past experiences

• Discuss how past experiences can be a useful way of learning, these

experiences don’t need to be successful - poor experiences or failure can still be useful learning situations.

• Students should be aware that learning can come from past experiences that were successful and fulfilling

• Students should be aware that learning can come from past experiences that were unsuccessful or demoralising.

• Tutors should try and bring out the positive when things go wrong

• Practical tasks • Assembly tasks • Testing energy systems

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Developing presentation skills

• Presentation skills are relevant to all Units in the Course.

• Students often find giving presentations a daunting task. They should progress from a group presentation onto individual presentations. Staff should demonstrate how presentations should be planned and practised. Students may feel comfortable using mobile phone technology to video a presentation, load it onto a computer and run it on the screen.

• Staff should demonstrate how to give a presentation.

• Give students opportunities to give very short talks throughout the Course to help develop these skills

• Give encouragement to help them overcome fears.

• Use a range of media to help overcome fears eg. PowerPoint or video.

• Short talks

• Tutor support and discussions

• Planning

Developing creativity skills

• Creativity should be introduced as a skill which comes up with novel

solutions to a problem. Creativity in design is the most usual way to demonstrate this but other ways can be used to show creativity eg. a new procedure to assemble a system, giving a presentation, methods of reducing their carbon footprint, integrating energy systems etc.

• Creativity will be recognised when students give presentations, ie. the methods they use should increasingly involve the use of technology eg. from initially giving a simple talk, moving on to using PowerPoint, digital pictures or/and video etc.

• Staff should demonstrate creative solutions to problems • Staff should give students feedback on how to increase their level of

creativity • Encourage novel ways of doing things.

• Planning work

• Carbon footprint

• Use of technology



Resources It is expected that students will have access to a classroom with computing facilities and an appropriately resourced workplace that includes workshop facilities. It is particularly important that, as the handling of tools and materials is an integral part of the unit, any participating centre has such resources and ensures safe working practices. Book Wind energy basics: a guide to small and micro wind systems Gipe, Paul White River Junction, Vt. : Chelsea Green Pub. Co, c1999. Online resources and websites Wind Turbine Classroom Resources http://www.click4eco.co.uk/ A comprehensive site from the Danish Wind Industry Association http://www.windpower.org/en/core.htm Wind turbine components and operation http://www.windmission.dk/workshop/BonusTurbine.pdf Usual Wikipedia style with lots of links to relevant information http://en.wikipedia.org/wiki/Wind_power Extensive use is made of Internet resources in this support pack and these are detailed throughout the Student Support Section. • Tools and Materials Wikipedia: free encyclopaedia http://en.wikipedia.org/wiki/Main_Page Tool-up (commercial site) http://www.tool-up.co.uk/



Encyclopaedia http://www.encyclopedia.com/ Technology Student http://www.technologystudent.com/index.htm FENC – aims to be the leading community for vocational blended learning http://www.fenc.co.uk • Working in Teams and Groups http://www.physics.udel.edu/~watson/scen103/colloq2000/workingingroups.html



Student Support Section



Tutor Note on Student Activities This section includes both student notes and examples of practical activities and includes: • Background information on renewable energy issues • Information relating to knowledge and understanding of wind turbines • Guidance on activities for Outcomes 1 – 5. Please note that the activities

shown for Outcomes 1 and 2 are intended as practice for the practical assessed elements of the Unit. Detailed guidance on the requirements for assessment will be found in the NAB item for this Unit.

• The focus in Outcome 3 is on team work and planning. Guidance and student activities will be found in the Course Guidance and Employability support materials.

• Extension notes and web-based activities providing more challenging information and tasks where appropriate for the student group are provided in the Appendix. Tutors should be selective in using this material.

Use of these materials is not mandatory and they are offered to centres as a flexible set of materials and activities which can be selected, altered and used to supplement tutors’ own tried and tested materials, or in whatever way suits individual centres and their particular situation. For example, in the case of the student activities you might want to talk through the instructions with the learners and then give the instructions out on paper as reminders. The notes are not intended in any way to replace the tutor! They should not be issued as a pack of student notes in their entirety. Rather they are designed to be issued in small sections only, to reinforce practical workshop activity. In the case of the student activities you might want to talk through the instructions with the learners and then give the instructions out on paper as reminders. Prior to any practical work, students are encouraged to read the background information/terminology/parameters related to wind turbine operation. However depending on the student group and because of the technical nature of the subject and the terminology, tutors may decide that handout materials should only be issued after the topic has been fully discussed with the students. Online research and practical activities will provide students with a more blended approach to teaching and learning. School students will be familiar with this approach. For students returning to study, you may need to spend time supporting them in the use of electronic resources. Useful online videos are available that will reinforce the learning of the practical energy systems.



Welcome to Energy: Domestic Wind Turbines Systems The purpose of this Unit is to introduce you to basic practices of assembling and testing a domestic wind turbine system and to give you some experience in handling tools and equipment which you will use when you are carrying out the installation of a domestic wind turbine system. The unit is designed to be mainly practical but also has an emphasis on helping you develop employability skills. You will learn to carry out the tasks to assemble and test a wind turbine system safely by following safe working practices and following safety instructions. The skills and practices you learn during this unit will help you to decide if you would like to make a career in the Energy sector Listen to your tutors – they have the experience, knowledge and skills in the production and testing of domestic wind turbines systems which they want to pass on to you. Your tutors are there to help you and will welcome your questions. If at any time you are unsure or need to ask a question - just ask.



Introduction The energy crisis of the 1970’s was the first warning. As oil prices rose steadily the world began to take an interest in what was then called ‘alternative energy’. Since then the term renewable energy is more commonly used. This describes energy that come from renewable sources such as: • sun • wind • waves • tides • biomass • hydro, and • geothermal power. All of these can be used continually without running out and therefore provide a sustainable energy supply. This is in contrast with conventional fuels such as coal, oil and gas which will eventually run out. In recent years renewable energy has become ever more important as terms such as ‘climate change’, ‘greenhouse gases’ and ‘global warming’ have crept into our vocabulary. It is widely believed by scientists that global warming and climate change are inevitable unless we can cut down on Carbon Dioxide and other greenhouse gas emissions. Renewable energy technologies could help avoid these global threats. There are also arguments for nuclear power stations to be built again. These would avoid greenhouse gas emissions but they have other problems concerned with safety and disposal of radioactive waste. Wood, woodchip and wood pellets are another form of energy which is very effective for heating buildings. These are renewable resources and can be grown on a continual cycle. However, they do produce carbon dioxide when burned. The argument here is that they are carbon neutral. That means the trees absorb as much carbon dioxide during their growing period as they release when they are burned. How do domestic wind turbines fit into this overall picture? Well, they may well have a useful place. Suppose new houses are built to a high standard with very good insulation and double or triple glazing. In addition, low energy devices such as energy saving lamps are used. Then less energy will be required for the house. Some of this energy could come from a small wind turbine. This would work best if combined with a solar water heater, photovoltaic panels and possibly another



energy source such as a heat pump or biomass boiler. Several low energy houses have been built and work very successfully. What operates for one house can be replicated for many houses and the beneficial effect multiplied. So this is where small domestic size wind turbines fit into the whole picture. They will not solve the energy crisis on their own, but they can make a useful contribution.



Schematic of Typical Small Wind Turbine

Figure 1

Batteries Inverter

Blades Generator

Tail Vane

Mast or Tower

Lighting load



Block Diagram of how it works:

Figure 2

Blades

Nose cone

Generator Tail vane

Mast or tower

Guy wires

Foundations

Wind

Generator

Controller

Battery Charger

Battery

Inverter

Electricity



Types of Wind Turbine Horizontal Axis There is now a wide range of horizontal axis wind turbines available for domestic use. The most common is the three bladed type (see Figure 3).

Figure 3

The blades are attached to a generator and as the wind blows on the blades, the turbine rotates making the generator spin. This produces a voltage which can be used to power electrical devices such as lights. Other formats are two-bladed, four-bladed and six-bladed types (see Figure 4). Even single bladed designs with a counterweight have been tried but not developed commercially.

Figure 4



Upwind or Downwind? If the rotor faces towards the wind, this is called an upwind turbine. This is the most common type. A tail vane is required to turn the machine into the wind and to follow the wind when it changes direction. Larger wind turbines do not use a tail vane but have a wind direction sensor which operates a motor to drive the turbine round until it faces the wind. In the case of downwind turbines, the rotor faces away from the wind on the downwind side of the tower. This means that the turbine will automatically follow the wind direction. A small tail vane may be used for stability. This system has the disadvantage that the blades are in the shadow of the tower and experience a shock each time they rotate past the tower. This effect can cause vibration and damage.

Upwind Turbine

Downwind Turbine

Figure 5

Wind

Wind



Vertical Axis There are also a range of wind turbines known as vertical axis devices. These rotate around a vertical axis but there are a variety of types. The best known are: • Savonious rotor • Darrieus rotor There are many different modifications of these basic types.

Figure 6 Advantages and Disadvantages The main disadvantage of the vertical axis wind turbine compared to the horizontal axis is that it is less efficient. That means that for a given size you get less useful output and therefore you get less for your money. However, the vertical axis machines have two distinct advantages: • They can run in winds from all directions and do not require additional

equipment to turn them into the wind. • The generating equipment and control gear can all be placed at ground level

which is much more convenient for maintenance work. With a horizontal axis turbine you have to climb the mast to make repairs or else lower the machine to the ground. This can be hard work or can be expensive, requiring the use of a crane or mechanical loader.

Savonious Darrieus



Masts and Towers There are three main types of masts and towers in use with small wind turbines: • Guyed pole • Self supporting tower • Lattice tower Guyed Pole

A guyed pole mast consists of a steel tube hinged at the base to a foundation. In the case of very small machines, a scaffolding pole or a galvanised water pipe can be sufficient. This type of mast will have to be guyed using steel ropes. The guy wires must be attached near the top of the mast but low enough that they will not foul the blades. The other ends of the guy wires must be attached to anchors fixed securely in the ground.

Figure 7: Guyed pole mast



Self Supporting Tower The more expensive self supporting machines have galvanised towers. They are designed to be bolted to a steel plate that is embedded in the foundations. These are relatively convenient to erect and take down and look more attractive than supporting masts and wires.

Figure 8: A self supporting tower



Lattice Towers Some manufacturers use lattice towers. These are specially designed structures similar to electric pylons. The tower is made up from a number of struts and spars to form a strong self supporting structure.

Figure 9: A lattice tower



Applications Small wind turbines can be useful for a number of applications. • In a domestic situation, they can supply enough energy to power

the lights in a house. This is particularly effective if low energy lamps are used. To achieve this only a small wind turbine would be required. Anything from 60Watts upwards would work. The best approach is to use the wind turbine to charge a battery. This can then power an inverter which will increase the voltage to 240V and will power the house lights directly.

• Water heating is another application which is

suitable for wind power. In this case a larger machine would be required. Suitable machines are available in ratings of 1kW 1.5 kW, 2kW, 2.5 kW and so on. In this case batteries are not required and the wind energy can be used to heat up electric immersion heaters directly. The energy is stored as hot water and this method has the advantage that the energy does not have to be used right away. A good insulated hot water tank will store heat for several hours and provides a convenient method of storing the energy.

• Space heating would require larger wind turbines. To heat a

whole house would need a wind turbine of at least 5kW. Suitable machines are available at ratings of 5kW, 6kW, 10, kW, 15kW and 20kW. These could be used to heat up water directly as before and this could be stored and used for domestic hot water or fed to radiators in an existing central heating system. This is the most cost effective installation.

An alternative way is to connect up the wind turbine so that it is coupled to the National Grid system. Such a system can import power from the grid or export power to it. This approach has been supported by government grants in the form of Renewable Obligation Certificates (ROCS). This financial incentive helps to off-set the capital cost of the installation.

• Smaller wind turbines are frequently used by owners of

yachts and caravans. They are useful for supplying lighting, but can also supply power for a computer or charge batteries for radio and other navigational equipment.



A good approach to domestic wind power systems is the community approach. This is often adopted on islands or remote communities. In such cases several householders cooperate to install a larger wind turbine capable of meeting their combined needs. This could also be done by using a number of medium sized machines in conjunction with other energy systems such as hydro, solar or biomass. An excellent scheme of this type has been completed on the island of Eigg. This uses wind, hydro and solar equipment to supply the whole island with electricity. Eigg Community Project The Isle of Eigg electrification project is an attempt to develop an electricity supply for the island which is sustainable both environmentally and economically. The Isle of Eigg Heritage Trust formed a company, Eigg Electric Ltd, to procure and operate a mains-type electrical network system for the islanders. This provides an electrical supply similar to that enjoyed by people living on the mainland with the aim of generating predominantly renewable electricity which can supply a reliable 24 hour electricity supply for all islanders. Various renewable sources distributed around the island have been incorporated to allow diversity of energy supply, - a 9.9kW PV system, three hydro generation systems (6 kW, 6 kW & 100 kW) and a 24 kW wind farm supported by standby diesel generation and batteries to guarantee continuous availability of power. For more information on the project, go to the following website: http://www.windandsun.co.uk/projects_eigg.htm



Table of Good Practice in Small Wind Turbine Design

Variables Design solutions Additional comments. Horizontal axis The most common type

with a propeller shaped rotor.

Very efficient. High rotational speed. Needs to be turned into the wind.

Vertical axis Accepts wind from all

directions. High efficiency. High speed.

Number of blades Three blades are most

common but two or more can be used.

Low number of blades (low solidity) gives high speed, low torque. High number of blades (high solidity) gives high torque low speed.

Length of blades The longer the blade the

higher the swept area. The power output is directly proportional to the swept area.

Shape of blades Aerofoil shapes work

best. Asymmetrical aerofoils with one flat surface for horizontal axis. Symmetrical aerofoils for vertical axis.

Height The wind speed

increases with height so more power can be obtained.

A high tower is more costly and inconvenient for maintenance. A balance must be struck.

Wind direction Horizontal axis

machines must have a tail vane to turn them into the wind.

Other methods such as a sensor and geared motor drive can be used but are expensive.

Wind speed The wind turbine should

start operating at a wind speed of around 5m/sec.

It should be controlled or shut down in very high winds to avoid damage.

Power output The power output

depends on the swept area and the wind

This means that the output will rise very sharply with increase in



speed cubed. wind speed. Electricity generation Electricity generation is

the most widely used application.

Uses include battery charging, lighting and heating.

AC or DC For battery charging a

DC output is required. If the output is AC it can be rectified to DC.

Inverters The low voltage DC

output can be fed into an inverter to give mains voltage AC.

This would power normal domestic lighting circuits.

Direct heat An alternative approach

is to heat water direct from the wind energy by fluid friction.

The hot water can be used for domestic water supply or space heating through radiators or underfloor heating.



Tools and Materials Measuring Most engineering work needs to be as accurate as possible. This means that the measuring and marking of a work piece is very, very important. Measuring is a very under-rated skill that most people take for granted. However engineers do not. A wrong measurement can cost valuable time and money to a firm, so what seems like a simple skill is in fact something that requires patience and practice. Each time you measure and mark, try this simple rule: measure twice check twice mark once cut once Accurate measurement also depends on your eyesight and the quality of the measuring tool. Rule – Tape Measure Engineers usually use a steel rule marked off in millimetres and centimetres. For longer distances, such as those involved in large fabrications, steel or cloth tapes are used – these come in lengths from 3 metres to 30 metres. Care should always be taken that these tools are only used for measurement as they are precision instruments.



Marking Out Marking out usually means the marking of lines on metal. These can be straight lines or circles or centres. If the marking out is on wood then a pencil line will be good enough, but on metal a pencil line would be very hard to see. Marking Lines on Metal – Scribing The surface on most metals can be shiny or dull but in both cases the marking lines can be difficult to see. • On metal the line or mark is scratched (‘scribed’) on but even this can be

difficult to see.

• Very often the metal is coloured with a dye (usually blue) and this lets the marked line stand out. This means that the tool used for marking must be sharp to give a good clear thin line.

• This colourant can only be applied if the metal surface is clean, - no grease and oil on the surface.

The thinner the line the more accurate the measurement and in engineering most measurements need to be as accurate as possible. When marking out long, and perhaps not so accurate, distances such as fabrications French chalk is used without the need for a colourant. This chalk is hard and can be sharpened to a chisel point which is retained for a few markings. Scriber The scriber is made of hardened steel with a fine sharp point for marking fine lines on the metal surface. The point must be kept sharp to keep the lines fine for accurate marking.



Datum Points Datum points are used in marking out. • A datum point is really just a starting point.

• If more than one measurement is required, it makes good sense to make all measurements from a reference or datum point.

• The starting point on a map would be the same as a datum point. So in marking out, a datum point is where all measurements start or where they are taken from.



Cutting Filing File Selection Files can be classed by the file shape or by the spacing of the file teeth. The spacing of the file teeth is called the pitch, and it is the pitch that decides what file you should use for a particular material.

Name of File

Use Finish

Bastard

rough work rough

Second Cut

general work reasonable

Smooth

finishing work smooth

Remember, filing is a skill that only gets better with practice – don’t expect to be great at it first time around! So how do we file a piece of material? Straight Filing • Grip the handle and the point of the file and guide/push the file long ways

across the work piece.

• Apply pressure with the hand that’s on the point of the file and push with the hand on the file handle.

• Lift the file slightly off of the work piece on the return stroke.

• Practice makes perfect!

Start of stroke End of stroke



Draw Filing Draw filing is for finishing work. Hold the file with both hands and draw across the work piece to give a smooth and even finish. Filing Flat The filing flat method is used to file flat a bigger surface area. • Apply marking blue to a surface table and rub the work piece over it.

• This will show all the high spots.

• Take the file across the surface at 45°.

• After a few strokes, repeat this - but at right angles to the original direction. In the diagram the blue areas show the high spots.

Direction of second file strokes Direction of first file strokes

First file strokes Second file strokes

Remember practice makes perfect!



Filing Square Filing square means that two edges of the work piece will be filed to make a right angle. Each edge is filed and constantly checked against an engineer’s square. Like all filing this is a difficult skill to master. Test for Square Test for Level



Saw A hand saw used to cut metal is known as a hacksaw and comes in various sizes such as a junior hacksaw. The main type of hacksaw consists of a frame and a blade. The frame is adjustable to allow different sizes of blade to be inserted. The blade must be tensioned and inserted correctly. Junior hacksaws are not adjustable and the blade is tensioned by the spring of the frame. Blades are classified by the number of teeth per unit length – normally the number of teeth in a 25mm length. You would normally cut thick materials with a coarse blade and thin materials with a finer blade. When cutting soft materials such as aluminium a coarse blade should always be used to prevent the teeth being clogged. A special blade should be used when cutting stainless steel. The hacksaw blade should never be used without the frame. Snips and Shears Snips and shears are used to cut sheet and thin material. There are several types in everyday use: Straight snips - used for general purpose cutting, straight cuts and trimming excess material Curved snips - used for cutting circles or irregular shapes Universal shears - have offset handles allowing cuts to be made in any direction and come in right and left-handed versions. Jeweller’s snips - used on very thin material or when small cuts are required. All of the above operate in a similar way to a pair of household scissors. Bench shears – are usually fixed and mounted on the bench and are able to cut thicker material. They operate by a moving top blade being pressed down by a handle onto a fixed bottom blade.



Guillotines These machines can be operated manually or by power. Manual treadle guillotines rely on the strength of the operator’s leg to push down on the treadle. This operates the top cutting blade to push the material against the bottom fixed blade. The treadle also operates the hold down clamp to stop the material moving. Only light gauge (thin) materials can be cut by this method. Power guillotines are generally used for repetitive work and where thick materials need to be cut. Their capacities can go up to 20mm thick and they are able to cut long lengths. Power machines can be noisy during operations and ear protectors should be worn. Both types of guillotine will be fitted with guides to assist squareness. They often have back and front gauges so you don’t need to physically mark the material. This is useful when cutting a number of pieces of the same size.

Guillotines and similar machines should never be used without a guard in place. You should never work from the back of the machine. You should always keep your hands clear of the clamps and blades during operations.

On completion of the work all scrap material should be removed from the rear of the machine and power machines isolated (switched off).



Electrical Circuits

Generation Electricity can be generated either as a DC (Direct Current) or as AC (Alternating Current). A voltage is generated when a magnet is rotated within a set of windings or coils. The coils are usually made from copper wire to give a low electrical resistance and the magnet can be a permanent magnet or an electromagnet. There are many variations in generator design, but a simple schematic diagram showing the basic operation is shown in Figure 10 (a). Figure 10(a) The symbols normally used for AC and DC generators are shown in Figures 10 (b) and 10 (c).

Figure 10(b) Figure 10(c)



Waveforms AC Voltage A waveform is the name given to the graph of a voltage against time. An AC waveform would take the shape of a sine wave as shown in Figure 11. This voltage waveform alternates between positive and negative forming a sine wave pattern.

Figure 11 DC Voltage The graph of a DC voltage, on the other hand, is just a straight line. This is similar to the output of a battery as shown in Figure 12.

Figure 12



Battery Charging Because a DC generator has a waveform similar to a battery, it can be used to charge a battery directly as shown in Figure 13. In practice this is normally done through an electronic controller which ensures that the charging current is not too high and that the final voltage of the battery too high.

Figure 13 If an AC generator is used to charge a battery the output must be rectified. That means that the current is passed through a rectifier as shown in Figure 14. A rectifier is essentially a one-way valve which allows the current to flow in one direction only. This converts the AC output to DC which is suitable for battery charging.

Figure 14



Rectifiers and Inverters We have seen how a rectifier can change AC to DC. The opposite can also be done using a device called an inverter. This changes DC to AC by a system of electronic switching. Inverters are widely used with wind turbine systems as it means that a battery can be used to power normal AC systems at 240volts which is the standard domestic voltage. See Figure 15.

Figure 15 Switching Circuits Lighting circuits can be switched in a number of ways. The most common of these are one-way switching where lights are controlled by one switch, and two-way switching where lights are controlled by two switches. Typical locations for two-way switching would be at the top and bottom of a stair or at either end of a corridor. The circuits are shown below in Figure 16 and Figure 17.

Figure 16

Figure 17



Simple Construction Projects Cup Anemometer This simple cup anemometer can be made by attaching the plastic cups to a central frame which can be made from plastic, plywood or metal. Suitable plastic cups can be made from plastic bottles or the tops of various domestic products. Those shown above were made from the containers for the toys in chocolate eggs. The cups are pop-riveted to the frame and then mounted on a small DC motor. DC motors act as generators when they are driven by a mechanical force. A typical 12volt motor will run at over 1000rpm. Wind devices rotate much slower at a few hundred revs per minute. This means that the anemometer will only produce 3 or 4 volts. However, this is enough to give a reading on a voltmeter which can then be calibrated to read wind speed in metres / second or miles per hour. On projects for young learners, a simple scale could just read CALM, BREEZE, WINDY, GALE. Using an anemometer to read the wind speed is a useful exercise and gives young learners a feel for the weather and an understanding of conditions required to use a wind turbine.



Propeller Type Anemometer An alternative type of anemometer is the propeller type. This can be made with a small propeller designed for model aeroplanes and available in model shops. This is shown attached to a small DC motor /generator. The propeller must be pointed into the wind. Again this device will produce an output of a few volts which is sufficient to provide a display on a voltmeter or a multi-meter using a suitable scale. This scale can then be calibrated in wind speed.

Small DC motor/generators can be found in many domestic appliances and also in old computers, printers, photocopiers and other office equipment. Small motors can also be found on cars for driving windscreen washer pumps and other applications. Again, these can be bought from model shops or second hand from scrap dealers at reasonable cost.

An alternative to the DC motor is the bicycle dynamo. This actually produces AC electricity. It will still produce enough electricity to give a reading on a voltmeter or multi-meter using an appropriate range.



Hot Wire Cut Blades

Very good aerofoil shaped blades can be made from polyurethane foam as shown above. These are made by cutting them from a sheet of the foam material using a hot wire. This technique is widely used by model aircraft enthusiasts. The blades can then be covered with brown paper and wood glue giving a construction known as BPF (brown paper, foam) which is very strong and light. NOTE !

This has the additional advantage of being fairly safe. An important safety issue is that the blades on a small wind turbine can rotate at extremely high speeds in a high wind (several thousand revs per minute). For this reason heavy wooden blades or sharp metal blades can be extremely DANGEROUS!

The blades in the photograph were made by a company in Blairgowrie called Foamwings: www.foamwings.co.uk Another useful website for construction projects is: www.windstuffnow.com



Small Wind Turbine Rotor • The blades can be attached to a central hub to form a turbine rotor. • This disc can be made from wood, plastic or metal. • The whole rotor is then attached to a small DC motor or a bicycle dynamo. • To complete the wind turbine a tail vane must also be attached to make the

turbine point into the wind. • The whole assembly must be mounted on a suitable mast which is high

enough so that the blades will not cause any damage. • The wind turbine should then generate electricity at wind speeds from around

5mph to approx 30mph. • It is not advisable to run small wind turbines in high winds as they can be

dangerous. The blades can fly off and the whole machine disintegrate, so some means must be found to turn the machine out of the wind or to stop it safely.



When a wind turbine generator rotates it produces a voltage. This voltage can be measured by connecting a voltmeter as shown. Voltmeters are always connected across the battery terminals ie. in parallel. • Voltages can be DC (direct current) or AC (alternating current) • A suitable AC or DC voltmeter must be used to measure voltage. For example

if the generator produces 12 volts DC, then a voltmeter with a range 0 to 20 volts could be used.

• Alternatively, a multi-meter can be used. This will have several different ranges to choose from. The multi-meter should be set to the most suitable range before connection. In this case 0 to 20 volts DC.

Generator + -

Voltmeter + _

Typical connection of Voltmeter to Generator



Schematic of small wind turbine system powering a lamp

• The generator is connected to the battery so that the battery is being charged. • The lamp is then connected to the battery. • An ammeter is shown connected in series with the lamp. Ammeters are

always connected in series so that they indicate the current flowing through them.

Again, a suitable scale must be chosen. For example if the lamp draws 2 amps DC, a suitable scale would be 0 to 5 amps DC.

Generator

Battery

lamp

ammeter



Practical Activities Outcome 1 Practical In this practical session you will connect up a wind generator, a battery charger, a battery and an inverter to the lighting load. You will have to: • List all steps to be taken to complete the installation • List health and safety requirements • Select the appropriate tools for the task • Use the tools and materials correctly • Carry out the task in the correct sequence • Check for quality of work on completion and make a list of any problems Equipment required • Small wind turbine • Suitable stand or clamp for turbine. • Battery • Battery charger • Inverter • Suitable cables • Switches and isolators • Terminal boxes and connectors • Lamp-holder with low energy lamp Tools required • Vice • Screw drivers • Side cutters • Pliers • Electric drill • Screws and fixings • Various spanners or socket set • Voltmeter • Ammeter



Procedure • Set up the wind turbine on a stand or clamp so that it is stable and safe. • Connect the output terminals using suitable cables to the terminal box. • Connect up the switch • Connect the battery terminal making sure that all connections are tight. • Connect from the battery to the inverter • Connect the output of the inverter to the consumer unit. This is now at 240

volts. • Alternatively, use 12 volt lamps.



Outcome 2 Practical In this section of the unit you are required to manufacture a metal part of a wind turbine. A suitable part might be the tail vane. This is a flat plate which ensures that the wind turbine faces into the wind. It can also be used as a means of furling the wind turbine when the wind becomes too strong. Tail vanes can be made from steel or aluminium plate. For small machines they could also be made from wood or plastic or a combination of materials. Figure 18 shows a range of shapes which can be used as tail vanes. You can choose any shape from the range shown or invent one of your own. Once you have decided on the shape make a drawing showing all the dimensions. You will have to: • List all steps to be taken to complete the manufacturing process • List health and safety requirements • Select the appropriate tools for the task • Use the tools and materials correctly • Carry out the task in the correct sequence • Check for quality of work on completion and list details of any departure from

specification Tools List • Pencil • Rule or measuring tape • Compasses • Electric drill • Hacksaw • File • Paint and paintbrush



Figure 18



Outcomes 3 and 4 Practical Team Work! You will have to work in a group to first of all draw up a plan for the assembly of a wind turbine system and then assemble and test the finished product. You’ll have to: • Have lots of group discussions! • Contribute to team discussions regarding assignment of tasks and timescales • Contribute to team discussion on use of resources • Contribute to group discussions to finalise the project plan including resources,

tasks and timescales all set out in sequence. • Research manufacturers’ catalogues, textbooks and Internet sites for ideas. • Decide on best options • Order equipment • Organise foundations • Organise lifting equipment • Allocate tasks — mechanical • Allocate tasks — electrical • Produce a team plan • Draw up a project plan against specification. Then: • Put your plan into action! You’ll be assessed on how well you: • Co-operate with others in the organising, sharing, and safe use of tools and

materials. • Co-operate with others in maintaining a safe, tidy working area. • Adhere to the agreed plan and work positively to complete tasks in the agreed

timescale. • In an agreed role, carry out practical tasks which contribute to the assembly of

the wind turbine system. • In an agreed role, carry out practical tasks which contribute to the testing of the

system. • Participate in a quality check of the finished work

against the given specification.



Working in Teams More and more organisations now use team working. The successful fulfilment of a project or process depends on the ability of the members of that team, both inside and outside the organisation, to work well together. After reading this section you should be better able to draw up the ground-rules by which your team will operate, generate ideas about ways of tackling a group project, divide up a task into its component parts and review your team’s performance. No study guide can really prepare you fully for team projects, because with these, perhaps more than any other aspect of your work at college: Direct experience is the key to learning. What is a Team? A team is a group of people who share a common objective and need to work together in order to achieve it. For example, a group of drama students putting on a play, a group of physicists working on a group research project, or a group of music students putting on a concert share the same common objective. However, they cannot achieve this unless they pool their talents and expertise in a team effort. What can be expected of a Team? Teams can help you to approach problems in new ways. They can also help you to learn, as fellow team members may raise ideas which you would never have thought of if you were working on your own. When they are successful, teams are often said to achieve something which is greater than the sum of the individual team members’ contributions. Establishing a Team Working as a team can however be very frustrating! You have to compromise, negotiate and to trust that others will do a task to the high standard that you set for yourself. Teams can take a while to form as you get to know each other and find out how each other works.



The following ideas may help you to form your team: Get to Know Your Fellow Team Members It may be that you don’t know everybody (or even anybody) in your team. Nobody much likes being addressed as, ‘Erm...’ or ‘You in the blue shirt’ so it’s best to make sure that everybody gets to know everybody else’s name right at the start. Why not spend your first meeting just getting to know each other? Set Ground-Rules Before you begin working together your team may wish to develop its own set of rules (often called ground-rules) under which it will operate. You can of course modify these later on. These ground-rules may cover topics such as: • How group decisions will be made. Will you act on the majority opinion or will

everybody have to be in agreement before you decide to do something? • How to ensure that everyone has a chance to voice their opinion (if they wish

to do so). • Punctuality for group meetings. • How everyone in the team is to be kept aware of progress. Regular group

meetings can be valuable but it can be difficult to find times convenient to all team members. One way (you can probably think of others) of ensuring good communication between team members is to agree that everyone will check either their departmental pigeon-hole or e-mail, or text messages every day (or even at certain times every day) throughout the duration of the project.



Agreeing the Objective for Your Team Project The first thing that a team should do when setting a project is to define their objectives clearly and also make sure that everyone is aware of the deadline by which these objectives need to be achieved. Generating Ideas Once the objectives have been defined, it is necessary to generate some ideas as to how to tackle the project. Brainstorming is one method of generating a large number of ideas. Its most important feature is that no-one passes judgment on any idea, however good or bad (or downright ridiculous!). The reason for this is that if someone laughs at your idea or describes it in uncomplimentary terms, you are unlikely to risk putting forward any others. As a result the whole team may lose out, because maybe your next idea would have been the best of the lot. The steps involved in a brainstorm are: • Write down the problem to be solved. • Team members put forward ideas and these are written down. No-one

comments as to whether the ideas are good or bad. • After an agreed period of time (or once the supply of ideas has dried up) the

team decides which of the ideas suggested it will use in tackling the project.



Planning how Your Team will Tackle the Project It may be easier to manage the co-ordination of the team if the project is divided into smaller tasks and group members work on these either individually or in pairs. For example, if you have been asked to research a topic and produce a poster on it, the stages of production might involve the following tasks: 1. Gathering information. 2. Selecting from this what will be used on the poster. 3. Designing the poster’s layout. 4. Writing text. 5. Preparing illustrations. 6. Putting the poster together. 7. Handing it in for marking. When you are deciding who should do what, it’s worth finding out the particular skills or interests that team members have. For example, one individual might be particularly good at researching information in the library; another may be fully conversant with the use of computer graphics packages whilst another person’s particular skills may lie in organising and co-coordinating the group effort. It is commonly recognised that individuals need to take on many different roles if the team is to be successful. Some roles relate to getting the task done (eg. gathering information; putting the poster together) and other roles relate to making sure that the team operates smoothly and effectively. In a small team it is likely that you will take on many different roles relating to both the task and the team. However, it is important to realise that no-one’s role is better than another. All of the roles are essential if the team is to succeed. A successful team will make the most of the strengths of its individual members.



Thinking about how you Work as a Team Reviewing your team’s performance is an important part of any team project and is particularly valuable if you are going to work again as a team. Questions you might want to ask are: • What did the team do well? (and why?) • Were all members of the team clear about the team’s objective? • Was everyone clear about what they individually should be doing? • Was it easy to contact other members of the team when necessary? • Did everyone contribute equally? • What did you do as a team if one member did not pull their weight? Whatever questions you ask, don’t dwell on what went badly (or on who was to blame), but concentrate on how the task could be performed better next time. Allocating Marks In some units, once you have completed your team project you may receive a group mark which you are asked to distribute fairly between the group members. This gives the team the opportunity to penalise team members who have not contributed equally to the team project. Your lecturer will almost certainly give you guidance on how to allocate the marks. However, one situation that you may also like to consider (and perhaps discuss in your team even if it doesn’t arise) is what you would do if a member of your team had the brilliant idea which was the key to the successful completion of your team’s task but then did nothing else to help in any way; or someone dominated the team and didn’t allow anyone else to do anything.



Activity: Identify, establish and agree team roles Discuss with your team mates what you all think these team roles are and what team role(s) you will be adopting during the project. Then fill in the table. Team Role

Description of Role

Your Team Role

Leader

Worker

Finisher

Problem Solver

Your tutor will give you a series of planning sheets which you should use to both guide your team activities and to record what you have done.



Outcome 5 Evaluation In this part of the Unit you have to both evaluate how the group worked together on the wind turbine project and how you contributed to the team. Your tutor will give you the evaluation sheets that you need to complete to show that you can: • Evaluate the strengths and weaknesses of the planning, assembly, and testing

of the wind turbine. • Evaluate the advantages and disadvantages of team working. • Evaluate your own contribution to the work of the team. • Identify action points for improvement in the production of the product and the

team working process.



Activity Evaluation Even though you’ve now finished the practical project, an important element has yet to be completed. In industry, it is a routine part of the job to evaluate how the job has gone. It’s in this way that businesses identify what they do well, where they need to improve and how their teams are working. Reflection is an important part of learning. Your tutor will give you worksheets to think about and record your evaluation of the production of the wind turbine, the team working process and your own contribution to the work of the team.

15



Activity Project Presentation You must now prepare and give your project presentation on your (and/or your team’s) evaluation of the production of the wind turbine and the team working process.



Appendix Extension Activities The notes which follow are provided to supplement the basic knowledge and understanding required at Intermediate 2. Tutors should these materials selectively as some will only be appropriate for more able students who are capable of working beyond Intermediate 2.



Power in the Wind The power in the wind can be calculated from a simple formula. The power is directly to the swept area. It is also proportional to the wind speed (velocity) cubed. If P = power, A = area swept by the rotor, and V = the wind velocity. Then the following equation will give an approximate value for power:

P = 0.5 x A x V3 Activity Work out what the power output will be for a wind turbine with blades 3 metres long operating in a wind of 12 m/sec. Assume the efficiency of the machine is 30%.



Solution First calculate the swept area. The area of a circle is 3.142 x radius squared A = 3.142 x 32

= 28.27 m2

Next calculate the power through this swept area.

P = 0.5 A V3

= 0.5 x 28.27 x 123

= 24,425 Watts or 24.4 kW But we must take into account the efficiency of the whole machine which is 30% So the final output power will be: P = 24.4 x 30% = 24.4 x 0.3 = 7.3 kW



The energy contained in the wind is due to its kinetic energy, and as the wind speed is always changing, dependent upon local weather conditions, then its energy content is also changing. Windier conditions can be seasonal, so luckily high wind speeds often occur at the times of the year when we might need a lot of electricity generated by this energy, ie. autumn/winter. This is good news for wind power generators as the cold seasons are when we require power the most. Activity Look at the variation of wind speed on this website: http://www.windpower.org/en/tour/wres/variab.htm Kinetic energy is determined by the following formula:- Where m = mass flow rate of wind (kg/s) v = speed of wind (m/s) This formula can be modified by replacing the mass term by

Avm ρ=.

Where: ρ = specific density (kg/m3) A = swept area of flow (m2) v = speed (m/s) Hence:

3

2

21

)(21

AvKE

vAvKE

ρ

ρ

=∴

=

2

21 mvKE =

4

2DA π=



ie. the power in the wind is proportional to:- i) the swept area of the turbine (or square of turbine diameter) ii) the cube of the speed

Figure 19

Swept circle by turbine blade

Diameter D



Activity Go this website and answer the following questions: http://www.windpower.org/en/tour/wres/enerwind.htm 1. What three factors are important in wind turbine design and location? 2. What is it about the design that is important in how much wind the turbine can

harvest? 3. If a turbine is 3m2 in diameter, how much wind energy capacity can it harvest? 4. If a cylindrical slice of air 1 metre thick moves through the 2m diameter rotor of

a typical domestic wind turbine, what is the mass of air passing through it?



Figure 20 Wind power can be plotted over a range of wind speeds to show the power in the wind at each speed. Note:- Wind power is greater at high speeds which is obvious, but perhaps not as great as imagined. This is due to the ‘cube’ rule ie. a small increase in wind speed can produce a substantially large increase in wind power. Note also that wind power is the ‘instantaneous’ power in the wind at that instant in time. If the wind velocity changes with time, then the wind power changes to a new ‘instantaneous’ value.

Power (Kw)

High wind power, high velocity because of “cube” rule

Increase in power



Activity Go to the website and answer the following questions: http://www.windpower.org/en/tour/wres/enrspeed.htm From the power graph: 1. At a wind speed of 8 metres per second we get a power amount of …….

W/m2 2. At 16 m/s wind speed we get a power output of …………W/m2 3. What is the mass flow rate of air passing through a wind turbine swept area of

3m2 when it is at a velocity of 12 m/s. Assume air density to be 1.25kg/m3 4. What is the swept area of a wind turbine which has a blade turning circle

diameter of 2.2m? Worked Example Air is passing through a swept circle of 2m diameter of a small wind turbine. If the wind speed is measured at 14m/s, determine the power contained in the wind at the turbine site. Assume specific density of air to be 1.25kg/m3 Can you see how this value relates to the previous graph? Note that the wind power in the graph is calibrated in W/m2

)389.5(5389

144

225.121

21

32

3

KWWatts

AvKE

=

××

××=

=

π

ρ



Activity Continue using the website: http://www.windpower.org/en/tour/wres/enrspeed.htm Determine the wind power for a wind speed of 10m/s Compare your answer with the graph. Activity Look at the website http://www.futurenergy.co.uk/turbine.html Work out the power contained in the wind when passing through the swept area of the FuturEnergy 1KW Upwind Turbine for its rated wind speed (assume an air density of 1.25kg/m3). We will look at the actual FE1012U, FE1024U, FE1048U type of wind turbine power curves a little later!



It is normal to express wind power in units of KWh, which is consistent with how we measure electrical energy consumption. (Look at the units listed on typical electricity meters or bills!) For each wind velocity:- KW x (number of hours at specific wind velocity) = KWh This is an important concept as it helps to ‘quantify’ the potential wind energy and more important, the wind turbine power output. More on this when we look at turbine power. Worked Example If the wind power is calculated to be 8KW for a period of 5 hours, what is the power in the wind in KWh?

4058 =×=KWh Activity 1. What is the power (KWh) for a wind power of 2.5KW over a period of 3.25

hours? 2. Produce a wind power – wind speed graph for a turbine swept area of 2m2



Wind Speed Measurement The most common method for measuring wind speed is the anemometer. However, there are several different types of measuring devices. These include: • The vertical axis cup anemometer • The horizontal axis propeller type anemometer • The hot wire anemometer, where the cooling effect of the wind is used to

determine its speed Cup anemometer t is obviously very important to know the wind speed variation, at a particular site especially if you are going to invest money in buying a wind turbine. It’s also useful for turbine designers to give advice on what would be the optimum turbine in terms of blade design, to meet the wind requirements of the site. Wind speed measurement is carried out locally by the use of an anemometer. The most basic form of this instrument is the cup-type anemometer, which consists of cups at the ends of arms that rotate when the wind blows. The instrument is calibrated such that the speed of rotation relates to the wind speed. Anemometers can be hand held or mounted on a mast.



The Beaufort Wind Scale Beaufort number

Description mph Effect on Land Effect at sea

0 Calm Less than 1

Still - Smoke rises vertically Surface like mirror

1 Light air 1 - 3 Smoke drifts Ripples form 2 Light breeze 4 - 7 Wind felt on face,

leaves rustle Small short wavelets, not breaking

3 Gentle breeze 8 - 12

Leaves and small twigs move, streamer extended

Large wavelets beginning to break, scattered white horses

4 Moderate breeze 13 - 18

Raises dust & papers. Moves twigs & small branches.

Small but longer waves, fairly frequent white horses.

5 Fresh breeze 19 - 24 Small trees begin to

sway.

Moderate waves, distinctly elongated, many whit horses, isolated spray.

6 Strong wind 25 - 31

Large branches move. Overhead wires whistle.

Large waves begin with extensive white foam crests breaking.

7 Moderate gale 32 - 38

Whole trees move, offers resistance to walkers.

Sea heaps up, white foam blown downwind

8

Fresh gale 39 - 46 Breaks twigs off trees, impedes progress.

Moderately high waves with crests of considerable length, spray blown from crests.

9 Strong gale 47 - 54 Blows off roof tiles

& chimney pots.

High waves, rolling sea, dense streaks of foam, spray.

10 Whole gale 55 - 63 Trees uprooted,

structural damage.

Heavy rolling sea, white with great foam patches, very high waves.

11 Storm 64 -72 Widespread

damage.

Extraordinarily high waves, spray impedes visibility.

12 Hurricane 73 - 82

Air full of foam and spray, sea entirely white.



Activity Go to this website and answer the questions: http://www.windpower.org/en/tour/wres/wndsprac.htm 1. Where is the best place to measure wind speed with an anemometer? 2. What does a data logger do with the anemometer readings? Other interesting links on anemometers: http://www.mybulgaria.info/modules.php?name=Wiki&title=Anemometer http://www.learn.londonmet.ac.uk/packages/clear/thermal/climate/describing/wind.html http://www.reuk.co.uk/print.php?article=Anemometer.htm Activity Making an anemometer: These are interesting websites for making a simple anemometer and testing your results. Try these out! http://www.reachoutmichigan.org/funexperiments/agesubject/lessons/energy/anemometer.html http://www.ciese.org/curriculum/weatherproj2/en/docs/anemometer.shtml



Presentation of Wind Data The quantifying of wind speed data at a site is done by recording wind speed over a specified period of time using a data logger linked to an anemometer and showing the results on a histogram (bar chart). The histogram shows an example of measured wind speed and time over a period of one month (30 days x 24 hours). The data logger compiles the wind speeds and calculates the number of hours at each speed.

Figure 21

Total hours (month) = 720 The peaks of each bar can be joined to form a ‘frequency distribution curve’. This is a useful method to mathematically work out a wind speed distribution.

Wind speed (m/s)

Hours

0 5 10 15

20

40

60

80

100

Frequency distribution curve



Interpretation of graph

Wind speed (m/s)

hours m/s

1 52 52

2 80 160

3 100 300

4 92 368

5 90 450

6 72 432

7 60 420

8 40 320

9 32 288

10 28 280

11 24 264

12 20 240

13 16 208

14 10 140

15 4 60

TOTAL 720 3982

Note the following key observations from the graph: 1. The average site wind speed = (3982 / 720 = 5.53m/s) 2. The maximum wind speed = 15m/s 3. The most common wind speed for site = 3m/s If you were designing a wind turbine to operate efficiently at this site, what wind speed might you design the turbine for?



Activity 1. Calculate the average wind speed for the site whose annual

measured wind speed distribution is shown in the bar chart below. 2. Plot a graph showing how the power in the wind (W/m2), varies with wind

speed over the range shown (ie. 1 – 20 m/s). Assume density of air = 1.25kg/m3

3. Construct a bar chart showing the annual energy delivered at each wind speed

in KWh / m2 per year. From that, work out the total site energy for a turning circle diameter of 2.2 metres.

Note that the bar chart should be plotted as shown in the example on the next page. Total hours (year) = 8760 (approximately)

Figure 22

200

400

600

800

1000

1200

1

Wind speed

hours

5 10 15 20



Figure 23 This is a very useful way to relate the ‘energy’ in the wind to the hours of wind speed. We will expand this theme later when analysing wind turbine energy output! Note also the frequency distribution curve superimposed on the bar chart. Let us now look at the significance of this curve. Although not as accurate as actual data logging to identify the ‘potential’ of the site, it could be used to justify the cost of actually taking detailed measurements. The bar chart just shown is a good example of a ‘typical’ wind distribution bar chart. This has a frequency distribution curve superimposed on the bar chart. In the absence of measured wind speed data at a site, it is normal to model the wind speed variation mathematically in the form of what is known as a ‘Weibull frequency distribution curve’: http://www.windpower.org/en/tour/wres/weibull.htm In Northern Europe, the shape of the distribution is given by the number 2 and is known as a Raleigh distribution. Such a distribution is similar to the curve profile shown in the previous bar chart. To use this method, you need to know the average wind speed for the site which can be obtained from your local Met Office.



Activity Go to website: http://www.windpower.org/en/tour/wres/weibull/index.htm to operate the on-line curve plotter. Plot a wind speed distribution for a mean wind speed of 7.5m/s and shape k = 2 Note that the vertical axis scale is calibrated per unit. If the readings are based on an annual quantity (8760 hours), then the scale is: 0.02 = 0.02 x 8760 = 175 hours 0.1 = 0.1 x 8760 = 876 hours Estimate the total energy present in the wind at each wind speed! By inserting another value for mean wind speed eg. 6.2m/s, work out the difference in the energy present in the wind. Wind speed variation with height The wind blows faster at higher altitudes because of the drag of the surface (sea or land) and the viscosity of the air. The standard height for meteorological observation wind speed data is 10m http://www.daviddarling.info/encyclopedia/W/AE_wind_turbine_tower_height.html



Power Extraction from the Wind Turbine (wind speed power curve) The wind speed power curve of a wind turbine is a graph that shows how large the electrical power output will be for the turbine at different wind speeds ie. it shows the instantaneous power output (KW) that the turbine can produce at a specific wind speed. An example of a small domestic turbine power graph is shown: http://www.futurenergy.co.uk/products.html then click on ‘downloads’ for the three turbine models: FE1012U, FE1024U, FE1048U. Look how the instantaneous power output increases as the wind speed increases: http://www.futurenergy.co.uk/FE1048U%20(408).pdf Wind turbines are commonly classed by their rated power (KW) at a specific wind speed, but actual annual energy output is far more important. The problem with small wind turbines is that they can be too small. Just as power falls disproportionately when wind speed drops the collection area increases disproportionately as you increase the length of the turbine blades. So a large turbine can generate reasonable amounts of power even in a relatively low wind. Larger power turbines tend to have a ‘flat top’ profile as shown:

Figure 24

KW

Wind speed

Rated power at rated wind speed range

Shut down wind speed

Start up wind speed

Power curve range



Activity Look at the website: http://www.windpower.org/en/tour/wres/pwr.htm 1. From the turbine power curve, what is the power developed by the turbine at a

wind speed of 16m/s? 2. If the wind blew at this speed for 85 hours in a month, how much energy

(KWh) does the turbine produce in this period? Capacity Factor A useful criterion to measure a wind turbine output is the use of the ‘capacity factor’. This is simply the wind turbine’s actual energy output for the year (KWh) divided by the energy output if the turbine were to operate at its rated power output for the full year. The Power Coefficient The power coefficient tells you how efficiently a turbine converts the energy in the wind to electricity. We just divide the electrical power output by the wind energy input to measure how technically efficient a wind turbine is. In other words, we take the power curve and divide it by the area of the rotor to get the power output per square metre (m2) of rotor area. For each wind speed, we then divide the result by the amount of power in the wind per square metre (m2).



Activity Look at the power curve of a turbine: http://www.windpower.org/en/tour/wres/pwr.htm See if you can plot the graph of turbine efficiency at the various wind speeds for the FE1048U (408PMG) domestic turbine. Comparison between total wind power and actual total turbine power

http://www.windpower.org/en/tour/wres/powdensi.htm

Figure 25

KWh

Wind speed

Total wind power KWh

Actual total turbine power (KWh)



Aerodynamics of Wind Turbines Concept of Lift & Drag Forces If we consider a flat plate lying horizontal in an air stream then the plate is subjected to a ‘drag’ force which tries to drag the plate in the same direction as the wind flow. Although this force would be minimal, it serves no practical purpose, particularly if we wanted motion in the vertical plane, ie. there is zero force in the vertical direction.

Figure 26

If we now consider the same plate lying in the vertical plane, then the plate is subjected to the maximum possible drag force which would have a larger impact on moving the plate in a horizontal direction. Again there would be zero force and hence movement in the vertical direction.

Figure 27

Drag force

AIR FLOW

Drag force

Air flow



Consider now the flat plate slightly angled to the air flow in which the force exerted on the plate can now be considered as being made up of two components ie. lift force and drag forces.

Figure 28 The lift force will cause movement in the vertical direction, whilst the drag force tries to ‘drag’ the plate in the horizontal direction. The angle at which the plate is positioned to the horizontal has now become important and is known as the ‘angle of attack’. Activity You can simulate this action with your hand sticking out the window of a moving car. Firstly, keep your hand horizontal. Your hand experiences very little drag force! Secondly, position your hand vertically. Your hand experiences the maximum amount of drag force. You may experience problems keeping your hand steady! Now position your hand a small angle to the horizontal. What happens to your hand now? The air stream tries to move it upwards, ie. lifts your hand vertically. The creation of vertical motion is therefore as a result of the orientation of your hand (blade) to the horizontal.

LIFT

DRAG

Air flow



Lift and Drag Forces The application of lift and drag forces in the analysis of horizontal axis wind turbine blades rotating in a vertical plane is slightly more complex to understand as it involves concepts like aerofoil section, angle of attack, relative velocity, and blade pitch angle. Consider a cross section of the blade at a radius ‘r’ from the centre of location Let’s now look down on top of a typical wind turbine blade cross section when the blade is at the twelve o clock position and identify firstly some of the key terms. Note • The direction of rotation of the blade (clockwise) and the direction of the blade

speed ie. horizontal to the right. • The undisturbed wind direction and the ‘apparent’ wind direction. If the

blade was stationary and you were standing on the blade, then the wind direction as you would see it would be the ‘undisturbed’ wind direction. If the blade started rotating at its operating speed in the direction shown, then the direction of the wind, as you would see it when standing on the moving blade, would be the ‘apparent wind’. This is the true direction of the wind when analysing forces acting on the blade and ultimately the power of the turbine. This is very important in understanding what follows.

• See http://www.windmission.dk/workshop/BonusTurbine.pdf for further information. In particular read the section ‘the aerodynamics of a man on a bicycle’.

• The shape of the blade, ie. aerodynamic or aerofoil section.

Figure 29

Direction of rotation

Turbine blade 12 o clock position

Undisturbed Wind

Apparent Wind direction as

b bl d

Blade speed direction

90o

Looking down on top of blade cross section

Aerofoil cross section

Radius “r”



Modern wind turbine blades are of an aerofoil section, designed to minimise drag and maximise the lift forces that we will describe next. The diagram below shows an aerofoil section with a predominant convex upper surface, a rounded leading edge which is in the direction of the wind and a relatively flat under surface facing the wind flow direction (note there are lots of different designs of aerofoil asymmetrical sections). The blade is designed with an angle of attack to the on coming wind, ie. the angle between the blade chord line and the wind direction. An angle of attack for an aerofoil section can vary between 2o and 20o depending upon the design. Normally the most effective angle of attack is around 3o. In large wind turbines, the ‘yawing’ mechanism is constantly realigning the wind turbine blades to any changes in wind direction via its control system.

Figure 30

Blade chord line

Apparent wind direction

Angle of attack

Convex upper surface

Roundedleading edge

Flat lower surface



When the wind flows over the top convex surface of the aerofoil a Bernoulli effect is created in terms of high pressure and low pressure zones.

Figure 31

The top part of the aerofoil section is actually shaped like a convergent/divergent nozzle (or half of one), where the influence of the bottom half of the section accelerates the air and creates the localised velocity increase.

Figure 32

For more information on the Bernoulli effect see: http://www.4physics.com/phy_demo/airattack.gif http://www.windmission.dk/workshop/BonusTurbine.pdf Read the section on LIFT and carry out the experiment with the two pieces of paper to show Bernoulli in action.

Normal pressure Normal velocity

High velocity creates Low pressure zone (Bernoulli effect)

Convergent / divergent nozzle h

Velocity increase Pressure decrease

Imaginary top half of nozzle



As the wind speed increases, the differential pressure across the turbine blade increases and lift force is created in the direction shown. However a drag force is also created on the blade in the direction of wind flow. As we will see, it is the lift force that is important for generating power. Continue to note the direction of rotation of the blade.

Figure 33 See http://www.windpower.org/en/tour/wtrb/lift.htm for further information on lift. See http://www.windpower.org/en/tour/wtrb/stall.htm for further information on stall.

Direction of blade motion

LIFT

DRAG

Wind force direction



To simulate creating a lift force, try holding a small bit of paper to your bottom lip, the paper will naturally deflect down due to gravity, but if you now blow over the top of the paper, the paper will rise, thus overcoming gravity. The air pressure on the underside is greater than the air pressure on top (its all velocity), hence the movement upwards. This shows how the Bernoulli effect is very powerful, to the extent that it keeps large aircraft in the air as the same effect occurs at the aircraft wings. Again noting the direction of motion of the blade, the actual force causing the blade motion is a result of the net effect of the horizontal components of the lift and drag forces.

Figure 34

Horizontal component of drag force opposing motion

Horizontal driving component of lift force

Direction of blade motion

LIFT

DRAG



Power Output Now we have got the turbine blade turning, we need to measure the power output developed by the blade. This is based on the concept of torque produced by the net driving force in the plane of rotation and the angular velocity of the turbine. Torque is a measure of ‘turning moment’ which is the net force multiplied by the radius (from the centre of rotation) at which it acts on the blade. Power is the product of torque and ‘angular velocity’ of the blade where angular velocity is related to revolutions per minute (rpm).

Figure 35 Activity If a turbine blade of a domestic wind turbine has a mean radius 1m, and rotates at 100rpm with a net wind force of 100N acting on it, what will be the power developed by the turbine if it has three blades? (answer 3.142KW)

Net force

Radius ‘r’ ωTP

rFT net

==

ω rad/s

602 Nπω =



Speed, Torque and Solidity The number of blades on a wind turbine defines its solidity. A two-bladed machine would have a low solidity compared to a five-bladed machine. Low solidity wind turbines operate at high speed, but have a relatively low torque. High solidity devices have a high torque but run at a low speed. For electricity generation, high speed, low solidity designs are usually chosen as electrical generators normally run at high speeds. Modern generators designed specially for small wind turbines normally run at speeds from 200 to 500 rpm. Taper and Twist It is customary to design wind turbine blades which are wide at the bottom and taper towards the tip. This gives the blade great strength at its root but makes it lighter and decreases the solidity at the tip. Another problem has to be addressed in blade design. As the blade rotates the tip has to travel much further than the root for each revolution. Therefore the tip is moving faster than the root. To get the angle of attack correct along the length of the wing it must be twisted so that the angle is high at the root and a small at the tip. Speed Control As the wind speed increases, the power output from the wind turbine will also increase. Some means must be found to use this power by increasing the electrical load on the system. In extreme conditions the turbine must be controlled or it would accelerate to a dangerous speed. This might cause mechanical damage. Methods of control are: • Furling • Feathering the blades. • Electronic control • Mechanical Brakes • Air brakes Furling The most common way to achieve this is for the tail vane to turn under the force of the wind at a certain wind speed. This causes the wind turbine to turn sideways to the wind and reduce speed. Alternatively, the wind turbine can tip over backwards away from the wind and this will have the same effect.



Feathering the blades means changing the angle of the blades to the wind. Increasing the angle of attack will reduce the rotational speed. This needs a complicated mechanical system and can be expensive. Therefore this type of control would be found on larger more costly machines. Angle of Twist In larger wind turbines where the rotating blades are much longer, then the magnitude and direction of the ‘relative’ velocity changes along the length of the blade, even although the undisturbed wind velocity and direction remains constant as well as turbine speed. This is because the linear velocity of the blade at each point in its length changes. Remember the formula that relates linear velocity (v) to angular velocity (ω)

602 NRvπω

ω

=

=

where N = rpm



Consider a point at the bottom of the blade R1, where the linear velocity vector is relatively low. But consider a point near the top of the blade R2, the linear velocity vector is much larger due to a corresponding increase in blade length for the same undisturbed wind velocity vector / direction, But notice how the magnitude and direction of the relative velocity changes. The direction changes are shown by the angle ‘θ’ which gets smaller.

Figure 36 As the angle ‘θ’ gets smaller, then if the blade has a constant angle of attack, the direction of the apparent wind speed is going to create a negative angle of attack at the expense of a loss in lift force.

R2

R1

θ

θ



Figure 37

In order to overcome this inefficiency, if the blade is designed to have a constant angle of attack along its length, then the blade requires to have an angle of twist over its length in order to ensure that the apparent wind speed vector is always in the correct direction to the aerofoil leading edge. See: http://www.windpower.org/en/tour/wtrb/rotor.htm for further explanation. http://www.windmission.dk/workshop/BonusTurbine.pdf and read the section on ‘The Changes of Forces along the Blade’.

Design angle of attack

Designed wind direction

-ve angle of attack

Wind direction at top of blade!



Blade Taper Another effect of increased relative wind velocity is to increase the pressure difference across the blade, particularly in sections near the tip. This in turn creates very large forces on the blade (and hence bending moments/stresses at the blade root). In order to preserve uniform force along the length of the blade, blades are tapered towards the tip to reduce surface area. Hence the large pressure differences are acting on smaller areas, evening out the force distribution along the blade. Tapered blades also reduce the weight of the blades, thus minimising the centrifugal force effects on the blade root.

Figure 38

Uniform force distribution along the blade

Tapered blade length

Centrifugal force

Stress at blade root due to centrifugal force



Activity Work out the power developed by a three bladed wind turbine operating at 80rpm if the net driving force measured at 2m intervals over a length of blade 10m long is 400N. Hint: Find the torque developed by each force then add together to find the total torque created by one blade. See: http://www.windpower.org/en/tour/wtrb/rotor.htm for further information. See: http://www.windpower.org/en/tour/design/index.htm for further information.



Wind/Solar and Biomass Projects Micro-generation Systems Micro-generation systems that include wind, solar and biomass technologies may, when integrated, allow small buildings to become self power generating for both heat and power without the need for connection to the Grid electrical supply. Micro wind turbines and PV solar collectors can provide electrical generation, and solar collectors and biomass boilers can provide thermal gain. Activity Look at the following website: http://www.zedfactory.com/pdf%20downloads/Microgeneration.pdf for further reading in this area. The following website gives some good examples of small scale renewable energy projects being developed in Scotland: http://www.energysavingtrust.org.uk/schri/community/projectresults.cfm?Start=121&o=0&r=0&t=0 A factsheet on small scale renewable energy projects is available on the following Energy Saving Trust website: http://www.energysavingtrust.org.uk/schri/renewable/ Off-grid system users either adapt to intermittent power or use batteries, photovoltaic or diesel systems to supplement the wind turbine.



Water Pumping Where wind turbines are used as the direct drive for a water pump, multi blade wind turbine pump units provide a high starting torque which allows the pump to start against a load, ie. head of water. The turbines blades turn through a small turning circle and the multi blade profile allows a high interaction with the wind at relatively low speeds. In theory, the more blades that a turbine has, then the more efficient its operation, however the larger amount of blades causes the wind flow pattern to be distorted preventing effective utilisation of the wind energy. For further information on wind water pumps, see: http://www.windpower.org/en/tour/design/optim.htm http://www.bwea.com/ref/pumps.html Economics of Small Scale Renewable Energy Projects Good case studies of various project costs are on the following website http://www.esru.strath.ac.uk/EandE/Web_sites/01-02/RE_info/small_scale.htm Activity: The Economic Case for Domestic Wind Turbines The following website shows an excellent article that explores the economic feasibility of domestic wind power. You need to understand the concept of the unit KWh http://en.wikipedia.org/wiki/Watt-hour to follow the economics. Read through the information and try calculating the economic case for a wind turbine at your home by comparing the costs against existing electricity bills! http://www.greenliving.co.uk/Articles/theeconomiccasef.html The following website explains the process of ‘How to Buy a Swift Wind Turbine’ and the various procedures involved in the installation of the turbine. http://www.renewabledevices.com/swift/index.htm



Glossary of Terms

Term Meaning Biomass Biomass refers to living and recently dead

vegetable material that can be used as fuel. Examples would include woodchip, wood pellets, and a wide range of other plants.

Carbon dioxide Carbon dioxide is a gas made up of one part carbon to two parts oxygen. Animals breathe in oxygen and breathe out carbon dioxide. Plants absorb carbon dioxide and produce oxygen. If this balance is disturbed excessive carbon dioxide can lead to climate change. Many industrial processes produce carbon dioxide.

Carbon neutral The term carbon neutral applies to fuels such as wood pellets. The trees absorb carbon dioxide when they are growing but release carbon dioxide when they are burned. These quantities of carbon dioxide balance out and therefore the fuel is classed as carbon neutral.

Climate change Climate change is any long-term variation in the weather for a particular region. There are a variety of causes but recently climate change has been linked to the increase in greenhouse gases.

Furl Roll or fold up neatly and securely. Furling – equipment for rolling up sails securely.

Generator A generator is a device which converts mechanical energy into electrical energy. They are normally rotating electromagnetic machines.

Geothermal power Geothermal power is energy generated by heat stored beneath the earth’s surface. Examples of Geothermal power stations can be found in countries with high volcanic activity such as Iceland or New Zealand.

Greenhouse gases Greenhouse gases are the gases present in the earth's atmosphere which warm the earth’s surface due to the effect known as the greenhouse effect. The most common greenhouse gases are carbon dioxide and methane.

Global warming Global warming is the increase in the average temperature of the earth’s near-surface air and oceans. It has many contributing factors but one of these is believed to be greenhouse gases.



Inverter An inverter is a piece of electronic power equipment which can convert Direct Current (DC) electricity into Alternating Current (AC). This is often done in small renewable energy systems to convert 12V battery power into 240V, AC mains power.

Nuclear power Nuclear power stations produce electricity by raising steam from the heat produced by the fission of radioactive materials such as uranium.

Photovoltaic Photovoltaic devices produce electricity direct from sunlight. Arrays of photovoltaic (PV) devices can be mounted on roofs to power buildings.

Radioactive waste Radioactive wastes are materials containing radioactive chemicals produced in industrial processes such as nuclear power stations. They are highly poisonous and dangerous and often difficult to destroy. Current practice is to store the waste safely for a long time.

Sustainable energy Sustainable energy is the provision of energy such that it meets the needs of the present without damaging the ability of future generations to meet their needs. Sustainable energy includes Renewable Energy systems such as Wind, Solar, Wave, Tidal and Biomass.

Torque Torque is rotational force. For example if a shaft is rotated by a lever, the torque is the force applied multiplied by the length of the lever.

Turbine A turbine is a rotating device with a number of blades which will turn fluid motion into mechanical energy. They can be driven by steam, water (hydro), or wind.

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