s ustainable a rchitecture applied to r eplicable public a ccess buildings module 6 post occupancy...

Sustainable Architecture Applied to Replicable Public Access Buildings

www.sara-project.net

Module 6

Post occupancy evaluation and thermal comfort

Sustainable Architecture Applied to Replicable Public

Access Buildings


Contract: TREN/04/FP6EN/S07.31838

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Plan

1. Post Occupancy Evaluation2. Case of Study : SARA project3. Questionnaire model


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POE - POST OCCUPANCY EVALUATION

“Technically, POE studies of buildings involve systematic collection and evaluation of information about the performance of a building in use. Data collected can include measured information such as energy consumption, temperatures, lighting levels, acoustic performance etc., and survey data from the perspective of the occupants regarding issues such as comfort, aesthetics, occupant satisfaction, management, etc ..”

Gupta, R. (2006) Learning by doing: a post-occupancy building evaluation module for postgraduate architecture students


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POE & FSTC (1)

• The POE (Post Occupancy Evaluation) is concerned with the performance of the building (‘the building is often hot in summer’).

• the FSTC (Field Studies of Thermal Comfort) is concerned with the occupant of the building (‘I feel hot now’).

• The ‘function’ of the occupant in the POE is to provide a subjective measure of a building and act as its ‘memory’


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POE & FSTC (2)

• The POE survey puts little emphasis on measuring the physical characteristics of the environment (temperature etc) at the time of the evaluation

• In the thermal comfort survey the physical measurements are a key function because the aim is to predict the subjective from a knowledge of the physical.


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POE & FSTC (3)

• The FSTC is uses detailed experimental work done in laboratories and climate chambers to explain the physiological and physical and psychological processes which underlie thermal comfort

• In the same way POE can be informed by the results of FSTC which explore the responses of building occupants


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POE & FSTC (4)

• There is a rich interface between the two types of survey and the ways in which they complement each other.

• In particular the ways in which the information from comfort surveys might be of use to explore the subjective scales in a POE, both as regards their design and interpretation


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Thermal comfort

• Thermal comfort is famously described by ASHRAE Standard 55 as that condition of mind which expresses satisfaction with the thermal environment.

• A Psychological phenomenon not a physiological one (though with a base in physiology and physics)


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The lessons of comfort surveys (1)

• Field studies in buildings show that the subjective response is the driving force behind the behavioural reaction according the adaptive principal:

‘If a change occurs such as to produce discomfort, people react in ways which tend to restore their comfort’.


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The lessons of comfort surveys (2)

• Comfort is not just a response to thermal conditions, but part of an interaction between occupants and buildings

• Comfort is a goal to be sought from, not a product delivered by the building

• The occupants may change themselves, or use controls to change the condition to achieve comfort


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Occupant Building

Comfort is achieved by the occupants adapting to

the building

Or by the occupants adapting the building to

suit them

This has to be done within the climatic, social, economic and cultural context of the whole system


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Adaptive opportunity

• Crucial, therefore, to the likely success of any building in being comfortable are the adaptive opportunities it provides.

• Adaptive opportunities are those features of the building which allow the occupants to adapt themselves to the building or to adapt the environment in the building to their own requirements


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Data from Pakistan

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Indoor temperature

Clothing insulationAir velocityMetabolic rateSkin moisture

Personal Variables


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The result of these actions is shown in this graph of the level of discomfort at different indoor

temperatures among office workers in Pakistan

00.10.20.30.40.50.60.70.80.9

1

12 14 16 18 20 22 24 26 28 30 32 34 36 38

Mean indoor temperature oC

Prop

ortio

n of

subj

ects

com

forta

ble

Little discomfort

Source: Nicol, Raja, Allauddin & Jamy (1999) Energy and Buildings 30


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Different controls are used in different circumstances

Changes in use of windows, lights, fans and heaters with indoor temperature

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20%

40%

60%

80%

100%

0 5 10 15 20 25 30 35 40

Indoor globe tempeerature (C)

WLFH


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People adapt

• Over time the temperature which people find comfortable is close to the mean temperature they have experienced.

• In other words the conditions which occupants find comfortable are influenced their recent thermal experience.


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Results from field surveys

15

20

25

30

35

10 15 20 25 30 35 40

Mean temperature experienced

Co

mfo

rt t

em

pe

ratu

re

Source: From Nicol & Humphreys Energy and Buildings 34


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Thermal indices

• Much of the work in thermal comfort (laboratory and field) has been aimed at perfecting an ‘index’ to describe comfort in terms of all the environmental and personal factors effecting comfort

• PMV, ET*, SET etc


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Thermal indices

• The problem with complex indices is not only how to collect the data, but also that the errors, both in the measurement of the variables and in the way they are ‘put together’, tend to be cumulative.

• The more complex the index the more important the errors and the less the likelihood that the index will be useful as a predictive tool.


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Variability and forgiveness (1)

• When occupants describe conditions as ‘hot’, they often mean ‘hot as compared to what might be expected’ or ‘hot as compared to what I normally expect’.

• This might imply the deviations from the ‘normal’ temperature would give rise to dissatisfaction and that variability leads to discomfort.


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Variability and forgiveness (2)

• But temperature change in buildings might be the result of occupant actions to achieve comfort as well as the result of factors beyond their control.

• Variable temperatures (assumed to be a ‘bad thing’ in the steady-state heat balance models of thermal comfort) might actually be improving occupant comfort.


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Variability

• Change is natural, stasis is only possible in certain (generally non-sustainable) circumstances.

• Thermal sensation relates to a running mean of temperature rather than its instantaneous.

• The relationship is not an exact one but the principle seems robust over a number of studies.


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Running mean temperature

The rate at which the comfort temperature changes is related to the running mean of the outdoor temperature (red line)

Outdoor temperatures in Oxford for June/July 1996

5

10

15

20

25

6/1/96 6/11/96 6/21/96 7/1/96 7/11/96 7/21/96

Te

mp

era

ture

daily mean To Trm33 Trm80 Tr0.90 Trm99


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Wilson Building, Open University, UK

Passive refurbishment of first floor studio


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0%

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100%

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Never Often Never Often

August 1995 (weather very hot)

September 1995

October 1995

Third floor Passive studio

How often is it too hot?

Source: POE research team at OBU


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very

sat

isfa

ctor

y

2 3 4 5 6

unsa

tisfa

ctor

y

studio

third floor0%

10%

20%

30%

40%

50%

60%

Overall satisfaction with the refurbishment

Source: POE research team at OBU


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OU Studio

• Perception of building changes with the outdoor conditions

• Overall satisfaction with passive Studio floor is better

• (also satisfaction better near window than away from it)



2. Case of study :SARA Project



In the UK the chosen project was of the new Administrative and Student Services Building (ASS), Southampton University. With 2500 m2 gross area this new department building, located on the existing campus site, comprises of a new 3 storeys high block linked to the old administrative block by an atrium.

Description of the UK building of SARA Project


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State of project progressSUMMER 2006

SUMMER 2006


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SUMMER 2006


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SUMMER 2006

SUMMER 2006


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SUMMER 2006WINTER 2006

SUMMER 2006


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WINTER 2006

SECOND, THIRD AND FORTH FLOORS OF NEW BUILDING

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Southampton University New office space temperature 2 Southampton University New office space temperature 3

Southampton University New office space temperature 4 Southampton University WS External Temp (53039)

WINTER 2006


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SECOND, THIRD AND FORTH FLOORS OF NEW&OLD BUILDING

WINTER 2006



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WINTER 2006



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WINTER 2006

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SECOND, THIRD AND FORTH FLOORS OF OLD BUILDING

WINTER 2006

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WINTER 2006


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WINTER 2006

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WINTER 2006

WINTER 2006WINTER 2006


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Concluding remarks

A demonstration project co-financed by the European Commission. (TREN/04/FP6EN/S07.31838/503188)

• Building performance: required fine tuning for design, fabric and services

• Users performance: participation and information


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Conclusions (1)

• Surveys, whether of buildings or of people, form part of a continuum.

• The climate chamber thermal comfort study might sit at one end and the POE at the other.

• The FSTC stands somewhere in between and must learn from and inform both.


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Conclusions (2)

• The FSTC is concerned with the physics and physiology of the climate chamber study but not constrained by the implied image of humans as animals with clothes.

• At the same time because the context of the FSTC is almost always a building, the findings of field studies will often touch closely on the evaluation of buildings:


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Conclusions (3)

• Thermal comfort is a goal of building occupants and not simply a product of the building services, though the building services provide some of the means by which the goal is achieved.

• Buildings and their occupants interact continually and the relationship between them is a dynamic one.


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Conclusions (4)

• The use of building controls should be a concern for future energy research

• In using occupants as part of the means to measure buildings, POE should understand the changing nature of the ‘comfort’ the occupants are being used to measure.

• This has profound implications for the reproducibility of the POE survey results.



3. Questionnaire model

Used in the framework of the SARA project


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Project SARA European Commission – Framework VI

Oxford Brookes University

Survey at the ASSBuilding, December 2005 University of Southampton

This survey concerns the environment in your office. As you might know Project SARA aims to construct sustainable, cost effective, highly energy efficient, public-access eco-buildings that are immediately replicable at large scale in many locations. The eco-buildings will be monitored and a survey of user satisfaction will be done to assess their performance. At present we are asking your help in monitoring the new addition to the ASSBuilding. This questionnaire is concerned with the temperature, lighting, ventilation and overall comfort in your office. We would be grateful if you could answer all questions, but please do not feel that you need to take too much time to think about your answers. The questionnaire should take less than 10 minutes. YOURS ANSWERS WILL BE TREATED IN THE STRICTEST CONFIDENCE, NO INDIVIDUAL RESULTS WILL BE AVAILABLE TO ANYONE AND NO ONE WILL BE REFERRED BY NAME IN THE REPORT. YOU WILL BE GIVEN A NUMBER FOR PURPOSES OF DATA COLLECTING ONLY. If you have any queries about this questionnaire, please e-mail Maria Rita (Maita) Kessler ([email protected]) or call her on 07747 865 365.

THANK YOU FOR PARTICIPATING IN THIS SURVEY


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WINTER SURVEY DESK NUMBER ….. - (map of the floors) Background: a) For how long have you been in this desk? ……………………………………. b) Please tell us how many people share your office space:………………….. c) How do you come to work: walking ( ) bus ( ) bicycle ( ) car ( ) d) Do you feel that you are: by a window ( ) away from the window ( ) e) Do you feel affected by the window? Yes ( ) No ( ) f) If “Yes” please say in what way: ……………………………………………………………………………………… ……………………………………………………………………………………… NB – In the following questions please put a tick in the box, which best expresses, your judgement. Control: How much control do you feel that you have over the following aspects of your environment? Temperature None at all 1 2 3 4 5 6 7 A lot Heating None at all 1 2 3 4 5 6 7 A lot Cooling None at all 1 2 3 4 5 6 7 A lot Ventilation None at all 1 2 3 4 5 6 7 A lot Natural light None at all 1 2 3 4 5 6 7 A lot Lighting None at all 1 2 3 4 5 6 7 A lot Noise None at all 1 2 3 4 5 6 7 A lot


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Environment: 3.1 How frequently in the last month or two has the temperature been: Too high Never 1 2 3 4 5 6 7 Often Too low Never 1 2 3 4 5 6 7 Often Changeable Never 1 2 3 4 5 6 7 Often Cold in the morning Never 1 2 3 4 5 6 7 Often 3.2 How frequently have your found the air: Draughty Never 1 2 3 4 5 6 7 Often Stuffy Never 1 2 3 4 5 6 7 Often Smelly Never 1 2 3 4 5 6 7 Often Dusty Never 1 2 3 4 5 6 7 Often 3.3 About natural light - How often have you had problems from the following: Too little daylight Never 1 2 3 4 5 6 7 Often Too much daylight Never 1 2 3 4 5 6 7 Often Reflections on screen Never 1 2 3 4 5 6 7 Often Discomfort from the sun Never 1 2 3 4 5 6 7 Often 3.3 About artificial light - How often have you had problems from the following: Too dark ambience Never 1 2 3 4 5 6 7 Often Too dark to work Never 1 2 3 4 5 6 7 Often Reflections on screen Never 1 2 3 4 5 6 7 Often No control over the lighting

Never 1 2 3 4 5 6 7 Often


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3.4 How much of a nuisance is the noise from: Outside Never 1 2 3 4 5 6 7 Often Atria Never 1 2 3 4 5 6 7 Often Other people Never 1 2 3 4 5 6 7 Often Office equipment Never 1 2 3 4 5 6 7 Often 4. Your ability to work: To what extent have the following affected your normal level of productivity in the last two weeks: Too hot in the morning

No effect

1 2 3 4 5 6 7 Badly affected

Too hot in the afternoon

No effect


Too cold in the morning

No effect


Too cold in the afternoon

No effect


Glare from window

No effect


We are very interested to hear any comments that you may have concerning the issues raised in this questionnaire. Please use this space (and the back of the form if necessary) to make any comments you wish. Thank you for your time.

s ustainable a rchitecture applied to r eplicable public a ccess buildings module 6 post occupancy...

Documents

poe fstc

ccess buildings

r eplicable public

s ustainable

poe survey

poe studies of buildings

thermal comfort slide

poe post occupancy evaluation