Page | 1

Detailed Design

Faucet-Powered Generator

Seth Forney

Tim Heindl

Aaron Weiss

Fikremariam Yami

April 16, 2010

Team I

Page | 2

Executive Summary

This report contains a design proposal for a water powered generator designed to attach the

customer's sink faucet. This product will use sink flow to spin a small water pinwheel which

will generate electricity through the attached electrical generator. The electricity generated could

be used for a number of different applications, such as charging an electric razor or toothbrush,

recharging batteries, or providing light to the bathroom. The high cost of electricity makes this

product useful and money-saving for the customer.

The design described in this proposal report is for an off-set Pelton style water pinwheel. This

product will be easy to manufacture, contain waterproof housing to operate reliably in a high-

water environment, and be inexpensive for both the manufacturer and the customer. As water

flows from the faucet head through the device, the kinetic energy of the flow is transferred as the

flow spins the water pinwheel. This torque is translated through a shaft which is connected to an

electrical generator. After performing a conservation of momentum calculation and comparing

the results to the theoretical power produced via flow calculations, it was determined that the

output voltage of the system would be 4.4 Volts. This exceeds the minimum design requirement

of 1.5 Volts. Additionally, after performing an economic analysis of the design project, it was

determined that the NPV value of the project was $686,291.07.

This product utilizes energy from the water flow which normally goes to waste. In the long

term, this product will pay for itself with the electricity it produces, making it a great buy for any

customer.

Page | 3

Table of Contents

Executive Summary ....................................................................... Error! Bookmark not defined.

1. Introduction ................................................................................................................................. 4

1.1 Problem Statement ................................................................................................................ 4

1.2 Background Information ....................................................................................................... 4

1.3 Project Planning....................................................................................................................4

2. Customer Needs and Engineering Specifications ....................................................................... 5

2.1 Customer Needs Assesment .................................................................................................. 5

2.2 Engineering Specifications .................................................................................................... 6

3. Concept Development

3.1 External Search ..................................................................................................................... 8

3.2 Black box Model..................................................................................................................9

3.3 Concept Generation...............................................................................................................9

3.4 Concept Selection................................................................................................................10

4. Detailed Design ......................................................................................................................... 12

4.1 Description of Chosen Design............................................................................................. 12

4.2 Analysis Calculations .......................................................................................................... 13

4.3 Test Procedure ..................................................................................................................... 17

5. Mass Production........................................................................................................................ 18

5.1 Material Selection and Fabrication Process ........................................................................ 18

5.2 Bill of Materials for Mass Production ................................................................................. 19

5.3 Economic Analysis for Full Scale ....................................................................................... 19

6. Conclusions ............................................................................................................................... 19

7. Supporting Materials ................................................................................................................. 19

7.1 References ........................................................................................................................... 19

Appendix A - Project Management .............................................................................................. 21

Appendix B - External Search Results.......................................................................................... 23

Appendix C - Blackbox Decomposition ....................................................................................... 27

Appendix D - Scoping Calculations ............................................................................................. 28

Appendix E - Bill of Materials for Mass Production .................................................................... 36

Appendix F - Full Scale Economic Analysis ................................................................................ 38

Appendix G - Dimensioned Drawings of Final Design ................................................................ 40

Page | 4

1. Introduction

1.1 Problem Statement

The assigned task is to design and produce a product which will utilize the flow energy of a

customer's faucet by producing electricity through the use of an electrical generator.

Additionally, the team will propose an accessory for the product which will make use of this

electricity. In order to create such a product, the needs of the customer are of critical importance.

The goal of the design project is to create a high performance and efficient product which is

attractive and relatively inexpensive (retails under $50 dollars). Additionally, the product must

attach securely to a faucet with 3/8-18 NPS internal pipe thread and contain identical threading at

the termination point of the flow. The total length of the device should be less than 4" and be

self contained. Finally, the device must be reliable in the wet environment and end in vertical

downward discharge of water.

1.2 Background Information

The team working on this project is a group of four junior level mechanical engineers. The team

has experience with Solidworks for generating solid models for the design. Additionally, the

team working on this project has experience with the design process, background in reverse

engineering, and Learning Factor certification for prototype creation.

1.3 Project Planning

First, the team developed a list of customer needs which would be the basis for the proposed

design. After analyzing these needs, a series of engineering specifications were created in order

to explicitly state what our team's design had to accomplish. In addition to creating customer

needs and engineering specifications, the team dissected the problem using the black box method

and performed external research and patent searches. While using the patents as ideas during

concept generation, the team also explored different types of water turbines in order to get a

better understanding of which type of pinwheel would work best for this relatively low-flow

setting.

A series of scoping calculations were performed to determine the volumetric flow rate of the sink

and pressure of the flow. Using this data, it was possible to determine the optimal flow rate to

produce the most power at the generator. Finally, several concepts were generated and scored

based on the customer needs we had established. Using this selection process, the team decided

to proceed with the off-set pelton style water pinwheel. Included in this report are all of the

Page | 5

above mentioned features leading to this decision, a Solidworks model of the concept, and a bill

of materials for the proposed design.

2. Customer Needs and Specifications

2.1 Customer Needs Assessment

The team began by generating a list of customer needs based on those given in the problem

description. After each customer need was clearly identified, the team proceeded to use the AHP

method in order to properly weight each need (Table 1). First, the customer needs were placed

into a screening matrix to compare the importance of each customer need. This matrix displayed

whether any given customer need was more important, less important, or of equal importance to

any other category. The customer needs, in order of importance were: performance, cost, ease of

use/safety, durability, appearance, and environmental effects. Safety was grouped with ease of

use for multiple reasons. Firstly, grouping safety with ease of use keeps the number of needs to a

manageable six. Also, the safety of all of the designs was determined to be about equal, so it

would not affect the outcome of the selection process.

Table 1: AHP Ranking of Needs

Customer Need Key

1 High performance

2 Low cost

3 Appearance

4 Ease of use/Safety

5 Durability

6 Environmentally friendly

The resulting matrix was used as a basis to develop the weighted comparison matrix (Table 2).

In this matrix, the weighted number of each customer need was the numerator over the weighted

number of its competing need. This pattern was repeated for each cell of the matrix until a net

score could be tallied. The net score was used to figure out the overall weighted percent to be

used for future matrices during concept selection.

1 2 3 4 5 6 Net Score Rank Weight

1 X 1 1 1 1 1 5 1 6

2 -1 X 1 0 1 1 2 2 4

3 -1 -1 X -1 0 1 -2 5 3

4 -1 0 1 X 1 1 2 2 4

5 -1 -1 0 -1 X 1 -2 4 3

6 -1 -1 -1 -1 -1 X -6 6 1

Page | 6

Table 2: Weighting of Customer Needs

1 2 3 4 5 6 Net Score Weight

1 X 6/4 6/3 6/4 6/3 6/1 13 30%

2 4/6 X 4/3 4/4 4/3 4/1 8.33 20%

3 3/6 3/4 X 3/4 3/3 3/1 6 14%

4 4/6 4/4 4/3 X 4/3 4/1 8.33 20%

5 3/6 3/4 3/3 3/4 X 3/1 6 14%

6 1/6 1/4 1/3 1/4 1/3 X 1.33 2%

2.2 Engineering Specifications

Following the customer needs assessment, all data collected was used in the various tables

created for engineering specifications. A list of metrics was established to show: the calculated

importance, units, and ideal value of each metric (Table 3). The ideal values were created by

either referring to the problem constraints or estimating them based on knowledge and past

experience. These specifications will later become more accurate after more hand calculations

and testing is carried out.

Page | 7

Table 3: List of Engineering Specifications

Metric Importance Units Ideal Value

Power Generation 6 Watts > 25 Watts

Efficiency 6 Percent 90%

$50 Retail Cost 4 Dollars < $50

Time to attach 3 Seconds < 30 seconds

Vertical discharge 6 Degrees 90 degrees

Length < 4" 6 Inches < 4 inches

See internal workings of product 4 Binary Yes

Produce minimum of 1.5V 6 Volts >= 1.5 volts

Load of 10 Ohm 6 Ohms 10 ohms

One Assembly/Component 6 Binary 1 component

Lifetime to Failure 3 Number > 5 yrs of avg. use

Positive Voltage Output 6 ± +

Components nontoxic 1 Binary Yes

3/8-18 NPS Internal Pipe Thread 6 Binary Yes

Watertight 6 Binary Yes

A QFD (Table 4) was created to clearly illustrate how each specification relates to the customer

needs. Although, the exact power generation and efficiency have not yet been computed, it is

known that the target cost of the final product is $50 or less. The task's progress can be found by

referring to the team’s Gantt chart, which is frequently updated.

Page | 8

Table 4: QFD Matrix

Po

wer

Gen

erat

ion

Eff

icie

ncy

$5

0 R

etai

l C

ost

Tim

e to

att

ach

ver

tica

l dis

char

ge

Len

gth

< 4

"

See

inte

rnal

wo

rkin

gs

of

pro

du

ct

Pro

du

ce m

inim

um

of

1.5

V

On

e A

ssem

bly

/Com

po

nen

t

Lif

etim

e to

Fai

lure

Po

siti

ve

Vo

ltag

e O

utp

ut

Co

mp

onen

ts n

ot

toxic

3/8

-18

NP

S I

nte

rnal

Pip

e T

hre

ad

Wat

erti

ght

High Performance X X X X

Low Cost X

Attractive

Appearance X

Easy to Attach X X X

Doesn't hinder

faucet function X X

Self Contained

Device X

Function Reliably

and Safely X X

Ease of

Maintenance X

Environmentally

Friendly X

3. Concept Development

3.1 External Search

The team performed an external search to determine what similar products have been patented or

are on the market. The first, “Self-Powered Miniature Liquid Treatment System[1],” presents a

system which can be attached to a faucet and use that flow to turn a Pelton turbine. The power

created by this turbine powers an ultraviolet light used to treat the water. The second, “Water

Page | 9

Faucet Generated Emergency Lighting System[2],” attaches to a faucet and uses a diverter in the

attachment to direct water over a turbine. This power is then used to power a light to be used in

emergencies. The third, “Water Powered Rotating Shower Brush[3],” uses water pressure to turn

a system of gears, which are used to rotate a shower brush. Finally, the fourth, “Small Power

Generating Device and Water Faucet Device[4],” has a radial flow turbine which is powered by

running water and can be used to produce power. The patent does not explicitly suggest a use for

this power. A summary of these results can be found in Appendix B. One product specifically on

the market is Sylvania’s Ecolight shower light[5]. The Ecolight uses an axial reaction turbine to

generate power from the flow of a shower head. This power is used to power a light to be used in

the shower. The Ecolight has relatively mixed reviews, but as it is one of the few products that is

similar to this project, it can be considered the benchmark for this type of product.

3.2 Black Box Model

The team evaluated the problem as a whole through the black box modeling technique. A black

box model of the problem can be found in Appendix C.

3.3 Concept Generation

The team brainstormed and arrived at three possible concepts.

Concept A

Concept A (Figure 1) is an impulse turbine in which a Pelton-style pinwheel is placed in the

pipe. The water is then throttled by a diverter such that it only hits one side of the wheel. The

motor is placed outside of the pipe with the shaft doing through the wall of the pipe.

Concept B

Concept B (Figure 2) is similar to Concept A in that it is an impulse turbine with a Pelton-style

pinwheel. It differs from concept A in that the motor and wheel are offset from the stream, which

travels through a nozzle to increase its velocity. The generator is again placed outside of the pipe

in its own housing.

Concept C

Page | 10

Concept C (Figure 3) uses a radial flow turbine. The water is allowed to flow over the turbine

freely. However, since the motor must be placed outside of the flow in order to both shield it and

prevent the restriction of the flow, it is placed in its own housing to the side of the pipe with

gears used to turn the motor’s shaft.

Figure 1: Concept A Figure 2: Concept B Figure 3: Concept C

3.4 Concept Selection

These three concepts were then put into a concept scoring matrix (Table 5) for final selection.

The selection criteria are found in the left column of the matrix. The next column contains their

respective weights (see prior customer needs assessment for determination of weights). The team

rated each concept by each criterion on a 1-5 scale. Each rating was then multiplied by the

weight in order to get a weighted score. Finally, these weighted scores were summed to get a

score for each concept.

The most obvious deciding factor was performance. Concept B was determined to have the most

potential for high performance. The team’s research indicated that a Pelton-style impulse turbine

would be best suited for this circumstance, in which the flow has relatively high head and can be

throttled in order to increase the flow’s velocity[6]. Thus, concepts A and B received higher

scores. Also, it was assumed that water fed through a nozzle would have a more accurate flow

than one simply throttled to the side, thus increasing the turbine’s performance. Thus, Concept B

proved to be ranked the highest. Based on these scores, the team decided to go through with

Concept B.

Page | 11

Table 5: Concept Scoring Matrix

Criteria Weight Concept A Concept B Concept C

Performance 30% 3 0.9 5 1.5 2 0.6

Cost 20% 5 1 3 0.6 1 0.2

Appearance 14% 4 0.56 3 0.42 4 0.56

Ease of Use/Safety 20% 3 0.6 3 0.6 3 0.6

Durability 14% 3 0.42 4 0.56 1 0.14

Environmentally Friendly 2% 3 0.06 3 0.06 3 0.06

Total 3.54 3.74 2.16

Rank 2 1 3

Page | 12

4. Detailed Design

4.1 Description of the Chosen Design

As stated previously, the team chose the offset Pelton pinwheel design (Figure 4). In this design,

the motor and turbine are offset from the flow, which travels through a nozzle in order to

increase its velocity. The offset pinwheel design best fits the specifications that were set to

satisfy the primary purpose of the product. It has the highest expected performance rate of the

systems taken into consideration because it uses an impact turbine instead of a reactive turbine.

The disadvantage found in a reactive turbine is that there are two opposite forces applied to the

turbine; while this may be used for other purposes, it is not as efficient as the impact turbine

model for our product. Elevated performance in impact turbine is achieved through high pressure

gradient created at a nozzle. As the pressure changes, the kinetic energy of the water is increased

and the turbine is solely derived by the impact force collision at the blade of the turbine. In

addition, the offset pinwheel is designed for easy access for maintenance or repair. As it has few

parts and is relatively simple, product failure by fatigue can be prevented, giving this design a

greater life expectancy as well. Figure 5 shows an exploded view of the design, and detailed

drawings can be found in Appendix G. For the prototype, the turbine blade was rapid

prototyped, and its volume is 0.48 cubic inches.

Inlet Nozzle Turbine

(Within

Housing)

Motor Casing

(Motor inside)

Page | 13

Figure 4: SolidWorks Model of Final Design Concept

Figure 5: Exploded View of the Chosen Design

4.2 Analysis Calculations

Pelton turbines work most effectively for high velocity flows. Thus, the team did an assessment

of flow rate as it relates to pressure drop in the sink that will be used for testing. A pressure

measuring device was attached to the end of the test faucet and both of the faucet’s valves were

opened fully. The throttle on the pressure device was turned to a predetermined value, and then a

volume of liquid was obtained while being timed. Then, the volume of the liquid was measured

and the volume flow rate was calculated A summary of these results can be found in Appendix

D.1.

Using these results, the team calculated the ideal nozzle diameter to maximize the power of the

flow. These results can be found in Appendix D.2.

Motor Calculations[10]

The following motor performance calculations were performed in order to determine the overall

efficiency of the motor. These tabulated values can be found in Appendix D.3. This was done by

Housing

Outlet

Turbine Nozzle

Motor Motor Casing

Outlet

Page | 14

comparing the input power from the drill to the output power from the electric motor. In order to

arrive at these values, a series of formulas were used to evaluate the motor properties.

In order to determine the torque constants Ke and Kt, the following formula was used at no load

and stall conditions:

𝑇 = 𝑇𝑙𝑜𝑎𝑑 + 𝑇𝑙𝑜𝑠𝑠 =𝐾𝑡

𝑅𝑎

𝑉 − 𝐾𝑒𝜔 = 𝐾𝑡𝐼𝑎

After determining the constants, it was possible to determine the constant torque loss of

operating the motor. Following these calculations, the armature resistance was determined

through the following equation:

𝑉 = 𝑅𝑎𝐼𝑎 + 𝐾𝑒𝜔

Once this armature resistance was known, using the input voltage and currents, it was possible to

determine the input and output power, and thus the efficiency of the motor. All of the above

calculations are expressed in the data tables and graph below (Figure 6).

Figure 6: Motor Performance Curve

Generator Calculations

0

0.5

1

1.5

2

2.5

3

3.5

0

2

4

6

8

10

12

14

16

18

20

0 1000 2000 3000 4000 5000 6000

Applied Torque

Power In

Current

Power Out

Efficiency

Page | 15

The generator performance calculations were performed very similarly to the motor calculations.

These tabulated values can also be found in Appendix D.3. First, the input torque was calculated

using the constant torque loss expression using the following equation:

𝑇𝑖𝑛𝑝𝑢𝑡 − 𝑇𝑙𝑜𝑠𝑠 = 𝐾𝑇𝐼𝑎

Once this input torque was calculated, using the known armature and load resistances, it was

possible to determine the armature current of the generator:

𝐼𝑎 =𝐾𝐸𝜔

𝑅𝑎 + 𝑅𝑙

Using this data, it was simple to calculate the input and output power of the generator. Using

these values, the same efficiency formula for the motor could be applied to calculate the

generator efficiency:

𝜂 =𝑃𝑜𝑢𝑡

𝑃𝑖𝑛

These calculations are expressed in the graph below (Figure 7)

Figure 7: Generator Performance Curve

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0

2

4

6

8

10

12

14

0 1000 2000 3000 4000 5000

Applied Torque

Power In

Power Out

Current

Efficiency

Page | 16

In order to get an idea of voltage output from the generator, the team used an electric hand drill

to turn the motor shaft at various speeds and recorded the voltage output of the generator. A

summary of these results can be found in Appendix D.3.

Turbine Flow Analysis

In order to analyze the performance of the turbine, angular momentum calculations were

performed. For a turbine,

𝑊𝑑𝑜𝑡 ,𝑠𝑕𝑎𝑓𝑡 = 𝜔𝑇𝑠𝑕𝑎𝑓𝑡 = 𝜌𝜔𝑉𝑑𝑜𝑡 (𝑟2𝑉2,𝑡 − 𝑟1𝑉1,𝑡) [9]

Using this relationship, power and efficiency (assuming the input power is the maximum power

of the flow as determined in the initial flow analysis) were plotted against rpm (Figure 8 and 9).

For this analysis, in order to achieve a conservative estimate, it was assumed that when the flow

hits the turbine, it will be scattered exactly outward. The numerical results of this analysis can be

found in Appendix D.4

Figure 8: Theoretical Power delivered to generator vs RPM of Turbine

Figure 9: Torque Delivered to Generator vs RPM of Turbine

0

10

20

30

40

50

0 1000 2000 3000 4000

Po

we

r (W

atts

)

RPM

Power vs RPM

0

10

20

30

40

50

60

70

0 2000 4000 6000

Torque Delivered vs RPM

Torque Delivered vs RPM

RPM

mN-m

Page | 17

0

10

20

30

40

50

60

70

0 1000 2000 3000 4000 5000 6000

mN

-m

RPM

Turbine and Generator Torque at Operating Power

Generator Input Torque

Out of Turbine Torque

Predicting Output Voltage

In order to determine the output voltage of the system, an operating turbine efficiency was

needed. Most products on the market operate at less than 5% efficiency. Therefore, the team

assumed that our design turbine had a 5% design efficiency. Therefore, using this assumed

efficiency and the theoretical power from the flow calculations, it was possible to determine the

out of turbine torque as a function of pinwheel RPM. Additionally, we plotted the generator

output torque. Together, the intersection point of these two curves represents the operating

conditions of the system at maximum power output. Figure 10 below shows this intersection

point which represents operating conditions at approximately 4300 RPM. Using these operating

conditions, it was possible to determine the output voltage of the system:

𝑃 =𝑉2

𝑅; 𝑉 = 𝑃𝑅 = 1.95 𝑊𝑎𝑡𝑡𝑠 ∗ (10 𝑂𝑕𝑚𝑠) = 𝟒. 𝟒 𝑽𝒐𝒍𝒕𝒔

Note that this final determined output voltage exceeds the design requirement of at least 1.5

Volts.

4.3 Test Procedure

The designed prototype will be brought to the required testing area (314 Reber building) for

experimentation and observation. The prototype set for use is one which was fully dimensioned

on SolidWorks. The faucet-powered generator also will include detailed drawings for each

component of the assembly to ensure proper installation. The sink has a 3/18-18 NPS internal

pipe thread that will be connected to the inlet of the generator. After the assembly is securely

Page | 18

fastened, the sink will be turned on, starting at a low volume flow rate. The valves of the sink

will then be opened until both the hot and cold valves are fully open.

Ideally, the combination of volume flow rate and pressure drop will create the perfect conditions

for producing maximum power and efficiency with the water turbine. By examining outlet

velocity and generator output, the team can determine the overall power and efficiency of the

generator as compared to the preliminary calculations. Although a perfect match between

theoretical and actual values cannot be expected, the results of this experiment should be close to

the predicted performance.

5. Mass Production

5.1 Material Selection and Fabrication Process for Mass Production

Table 6 below displays information for the project prototype for each component, quantity of

that component, material, and associated manufacturing process. Costs are not included in this

prototype analysis; however, for the mass production table seen below, cost of components and

manufacturing are estimated.

Table 6: Material and Fabrication Process for Prototype System

Table 7 below displays information for the actual design including each component, the quantity

of that component, the material, manufacturing process required for its production, and the total

cost. These materials have been selected for the mass production of at least 100,000 units.

Component Quantity Material Manufacturing Process

Generator 1 Pre-fabricated (composite) Pre-fabricated

Shaft 1 Plain Carbon Steel Drawn and Cut

Water Seals 3 plastic Shaped and Compression fit

Pinwheel 1 Pre-fabricated Rapid Prototyping

Generator Housing 1 Plexiglass Cut to shape and glued

Flow Guide

Housing 1 Plexiglass Cut to shape and glued

Nozzle 1 6061 Aluminum Cut, Shaped, & MIG Welded

Page | 19

Table 7: Material, Fabrication, and Cost Per Unit for Mass Production

5.2 Bill of Materials for Mass Production

A full bill of materials for mass production can be found in Appendix E.

5.3 Economic Analysis for Full Scale

A full economic analysis for full scale manufacturing can be found in Appendix F.

6. Conclusions

Overall, the team has made excellent progress in the design and development process for

creating this faucet-attached water powered generator. This product will satisfy all the customer

needs developed in our analysis while providing an excellent profit margin for the manufacturing

company. The design meets all project requirements including a produced output voltage of 4.4

Volts, which exceeds the design criteria of 1.5 Volts. Additionally, the economic analysis

showed a net present value of $686,291.07 for the project. This product will save the customer

money through the utilization of wasted flow energy to produce electricity for battery charging.

The team intends to move forward with the design process with this design proposal successfully

completed. A more detailed design analysis will now be performed, along with a supplementary

economic analysis for the product.

7. Supporting Materials

7.1 References

[1] Baarman, David W., and Thomas Leppien. Self-powered Miniature Liquid Treatment

System. Access Business Group International, assignee. Patent 6927501. 9 Aug. 2005. Print.

Component Quantity Material Manufacturing Process Cost

Generator 1 Pre-fabricated (composite) Pre-fabricated $5.00

Shaft 1 Plain Carbon Steel Drawn and Cut $0.75

Water Seals 3 plastic Cut to shape $2.50

Pinwheel 1 Pre-fabricated (aluminum) Rapid Prototyping $14.99

Generator Housing 1 6061 Aluminum Drawn and Cut $4.00

Flow Guide

Housing 1 6061 Aluminum Drawn and Cut $4.00

Nozzle 1 6061 Aluminum

Cut, Shaped, & MIG

Welded $3.50

Total Material Cost: $34.74

Page | 20

[2] Spiller, Andrew. Water Faucet Generated Emergency Lighting System. Patent 6036333. 14

Mar. 2000. Print.

[3] Terry, Robert L., and Daniel V. Sallis. Water Powered Rotating Shower Brush. Synergetic

Industries, Inc., assignee. Patent 4841590. 27 June 1989. Print.

[4] Yukinobu Yumita, Nagano. Small Power Generating Device and Water Faucet Device.

Kabushiki Kaisha Sankyo Seiki Seisakusho, Nagano; Toto Ltd., Fukuoka, assignee. Patent

6876100. 5 Apr. 2005. Print.

[5]“Sylvania Ecolight Water Powered LED Shower Light.” Sylvania, 2008.

<http://www.sylvania.com/AboutUs/Pressxpress/Tradeshowevents/Greenbuild2008/PressKit/Ec

oLightShowerLight.htm>

[6] Naveenagrawal. "Hydraulic Turbines: Definition and Basics." Hydraulic Turbines: Definition

and Basics. Haresh Khemani, 22 Nov. 2009. Web. 24 Mar. 2010.

<http://www.brighthub.com/engineering/mechanical/articles/26551.aspx>.

[7] "Stainless Steel Cylinder with Gecko." Stainless Steel Cylinder with Gecko. Memorial

Gallery, 2005. Web. 31 Mar. 2010. <http://www.funeral-urn.com/stainless-steel-cylinder-with-

gecko.aspx>.

[8] Ulrich, Karl T., and Steven D. Eppinger. Product Design and Development. 4th ed. New

York: McGraw-Hill Higher Education, 2007. Print.

[9] Cengel, Yunus A. and John. M. Cimbala. Fluid Mechanics: Fundamentals and Applications.

2nd ed. New York: McGraw-Hill, 2010. Print.

[10] Kenjo, T. and S. Nagamori. "Permanent Magnet and Brushless DC Motors". Oxford.

Clarendon Press. 1985

Page | 21

Appendix A: Project Management

Team roles

Program Manager (Tim Heindl) – Responsible for completing the project on schedule,

continuously monitors and updates the Gantt chart. With Fi, performed motor and

generator calculations and with Seth compiled report

Financial Officer (Aaron Weiss)– Responsible for tracking all expenditures, provides BOM

and economic analyses. Aided with SolidWorks and performed turbine flow calculations

with Seth

Record Keeper (Seth Forney) - Responsible for maintaining project records and

documentation, is the primary point of contact for all communications with the instructor.

Created SolidWorks Models, aided in turbine flow calculations, and compiled report

Safety Officer (Fikremariam Yami) - Responsible for the safety of the project. Performed

motor and generator calculations and drew sketches for concept selection.

Gantt Chart

The current Gantt chart illustrates all progress from the start of the project up to the most

recent team meeting on April 15, 2010. According to this chart, the team is currently on-task and

has made tremendous progress with the pending design.

Page | 22

Page | 23

Appendix B: External Search Results

Page | 24

Page | 25

Page | 26

Page | 27

Appendix C: Black Box Decomposition

Input Output

Energy (Mechanical) Energy (Electrical)

Open flow (activation of process) Power generation

Raw material Product component

The overall function of the new micro-hydropower system in product development.

Energy

Open faucet

Raw material

Illustration of the subfunctions of the micro-hydropower system intended to be produced.

Faucet head electric

generator

Gather kinetic

energy from

the fluid flow

Convert into

electrical energy

Power household

appliance

Initiate

pressure

gradient in the

flow

Draw flow of

water into the

system

Construct

fixed, self-

contained

components

entire system

Drive a generator

using a shaft

Page | 28

Appendix D: Scoping Calculations

D.1. Faucet Test

Flow rate = liters of water / amount of time needed

Power generated = flow rate * pressure drop

Power (Watts) and Pressure Drop (m^3/s) vs Flow Rate (m^3/s)

D.2. Nozzle Calculations

First, we begin with the conservation of mass relationship, since we assume no water leaks from the

system when the pinwheel is connected to the faucet:

0

10

20

30

40

50

60

70

80

90

0

50000

100000

150000

200000

250000

300000

350000

400000

0 0.0002 0.0004 0.0006 0.0008

Po

we

r (W

atts

)

Pre

ssu

re D

rop

(P

a)

Volume Flow Rate (m^3/s)pressure drop

Power

Pressure

Drop Pressure Drop (Pascals)

Volume

(L) Time (s)

Flow Rate

(L/s)

Flow Rate

(m^3/s)

Power

(Watts)

0 0 1.7 2.94 0.578231293 0.000578231 0

0 0 3.56 6.16 0.577922078 0.000577922 0

53 365422.1364 0

0 0 0

50 344737.8645 0.85 8.56 0.099299065 9.92991E-05 34.23214776

40 275790.2916 1.89 6.66 0.283783784 0.000283784 78.26481248

30 206842.7187 2.05 5.53 0.370705244 0.000370705 76.67768053

20 137895.1458 2.6 5.69 0.456942004 0.000456942 63.0100842

10 68947.5729 2.44 4.6 0.530434783 0.000530435 36.57219084

Page | 29

ṁ𝑖𝑛 𝑘𝑔

𝑠 = ṁ𝑜𝑢𝑡

𝑘𝑔

𝑠

Letting 1 subscripts represent flow into the system and 2 represent flow leaving the system, breaking

down this equation into its components gives:

𝜌1𝑉1𝐴1 = 𝜌2𝑉2𝐴2

Assuming the flow of water is incompressible, it is possible to state that ρ1 = ρ2 and thus the equation

simplifies:

𝑉1𝐴1 𝑚3

𝑠 = 𝑉2𝐴2

𝑚3

𝑠

Using the appropriate control volume for the system, we represent state 1 as the open flow conditions and

state 2 as the constricted nozzle flow at which maximum power exists. Therefore, we can solve for the

velocity and area at state 1 as follows:

Ṿ𝑉𝑜𝑙𝑢𝑚𝑒 𝐹𝑙𝑜𝑤 𝑅𝑎𝑡𝑒 𝑚3

𝑠 = 𝑉 ∗ 𝐴

Note: the measured open radius of the faucet is .337 in = .0085598 m

Ṿ𝑚𝑎𝑥𝑃 = . 000283784𝑚3

𝑠 = 𝑉1 𝜋 . 0085598 𝑚 2

𝑉1 𝑜𝑝𝑒𝑛 𝑓𝑙𝑜𝑤 = 𝟏. 𝟐𝟑𝟐𝟖𝟓𝒎

𝒔

In order to calculate the required radius of the nozzle in order to produce the desired power, use the

Bernoulli Energy Equation to calculate for V2 and then back calculate using the above relationship to

solve for A2:

1

2𝜌𝑉2 + 𝜌𝑔𝑧 + 𝑃 = 𝐶𝑜𝑛𝑠𝑡𝑎𝑛𝑡

1

2𝜌1𝑉1

2 + 𝜌1𝑔𝑧1 + 𝑃1 =1

2𝜌2𝑉2

2 + 𝜌1𝑔𝑧2 + 𝑃2

Continue to apply the incompressible assumption to set ρ1 = ρ2 and assume that the potential drop over the

height of the nozzle is negligible to cancel the potential energy terms. This leaves the remaining terms in

the energy equation:

1

2𝑉1

2 +𝑃1

𝜌=

1

2𝑉2

2 +𝑃2

𝜌 →

1

2 𝑉1

2 − 𝑉22 =

𝑃2 − 𝑃1

𝜌

Using 1000 kg/m3 as the value for the density of water, and 2.73e5 Pa as the delta P across the nozzle as

the flow is constricted, it is possible to solve for the speed of the water through the nozzle:

Page | 30

1

2 1.21

𝑚

𝑠

2

− 𝑉22 =

−2.73 𝑥 105 𝑘𝑔 𝑚𝑠2 𝑚2

1000𝑘𝑔𝑚3

𝑉2 𝑚

𝑠 = 𝟐𝟑. 𝟑𝟗𝟕𝟗

𝒎

𝒔

Using this value for exit velocity from the nozzle, it is possible to back calculate for the radius of the

nozzle as follows:

𝑉𝑑𝑜𝑡 𝑛𝑜𝑧𝑧𝑙𝑒= . 000283784

𝑚3

𝑠 = 23.3979

𝑚

𝑠 𝜋 𝑟𝑛𝑜𝑧𝑧𝑙𝑒

2

𝑟𝑛𝑜𝑧𝑧𝑙𝑒 = .0019651 𝑚𝑒𝑡𝑒𝑟𝑠

Converting this nozzle radius to inches gives:

𝑟𝑛𝑜𝑧𝑧𝑙𝑒 = . 𝟎𝟕𝟕𝟑𝟔𝟓𝟒 𝒊𝒏𝒄𝒉𝒆𝒔

D.3. Motor/Generator Data

Motor Data

Kt = 0.017698259

Td = In* Kt 0.000460155

Ke = 0.017698259

In = 0.026

Ra = Va/Is 11.32075472

Is = 1.06

Va = 12

Exp Drill Voltage rpm ω(rad/sec) Vb (Volts) I (Amps) Ta (N-m) P_in (W) P_out (W)

0.13 130 13.61356817 0.240936455 1.03871728 0.017923333 12.464607 0.244000512

0.235 250 26.17993878 0.463339337 1.019071692 0.01757564 12.22886 0.460129179

0.265 290 30.36872898 0.537473631 1.012523163 0.017459742 12.150278 0.530230186

0.37 400 41.88790205 0.741342939 0.994514707 0.017141024 11.934176 0.71800154

0.447 475 49.74188368 0.880344741 0.982236215 0.016923716 11.786835 0.841817522

0.53 590 61.78465552 1.093480836 0.963409193 0.016590511 11.56091 1.025038988

0.597 640 67.02064328 1.186148703 0.955223531 0.016445639 11.462682 1.102197286

0.669 715 74.87462491 1.325150504 0.942945039 0.016228331 11.31534 1.21509018

0.701 750 78.53981634 1.390018011 0.937215076 0.01612692 11.246581 1.266605367

Page | 31

0.773 840 87.9645943 1.556820173 0.922480885 0.015866151 11.069771 1.395659526

0.811 885 92.67698328 1.640221253 0.915113789 0.015735766 10.981365 1.458343334

0.886 960 100.5309649 1.779223055 0.902835297 0.015518458 10.834024 1.560085575

0.937 1010 105.7669527 1.871890922 0.894649635 0.015373586 10.735796 1.626017367

1.011 1100 115.1917306 2.038693083 0.879915444 0.015112817 10.558985 1.74087151

1.221 1360 142.418867 2.520565994 0.837350004 0.014359483 10.0482 2.045061229

1.435 1600 167.5516082 2.965371758 0.798058828 0.013664097 9.5767059 2.289441444

1.592 1800 188.4955592 3.336043227 0.765316182 0.013084609 9.1837942 2.46639074

1.78 2000 209.4395102 3.706714697 0.732573535 0.012505121 8.7908824 2.619066507

2.145 2500 261.7993878 4.633393371 0.650716919 0.011056402 7.808603 2.894559231

2700 282.7433388 5.004064841 0.617974272 0.010476914 7.4156913 2.962277643

2800 293.2153143 5.189400576 0.601602949 0.01018717 7.2192354 2.987034276

2900 303.6872898 5.374736311 0.585231626 0.009897426 7.0227795 3.005722526

3000 314.1592654 5.560072046 0.568860303 0.009607682 6.8263236 3.018342393

3200 335.1032164 5.930743515 0.536117656 0.009028194 6.4334119 3.025376981

3400 356.0471674 6.301414985 0.50337501 0.008448707 6.0405001 3.008138039

3600 376.9911184 6.672086455 0.470632363 0.007869219 5.6475884 2.966625568

3800 397.9350695 7.042757924 0.437889717 0.007289731 5.2546766 2.900839566

4000 418.8790205 7.413429394 0.40514707 0.006710243 4.8617648 2.810780035

4200 439.8229715 7.784100864 0.372404424 0.006130755 4.4688531 2.696446974

4400 460.7669225 8.154772334 0.339661777 0.005551267 4.0759413 2.557840383

4600 481.7108736 8.525443803 0.306919131 0.00497178 3.6830296 2.394960262

4800 502.6548246 8.896115273 0.274176484 0.004392292 3.2901178 2.207806612

5000 523.5987756 9.266786743 0.241433838 0.003812804 2.8972061 1.996379431

5200 544.5427266 9.637458212 0.208691191 0.003233316 2.5042943 1.760678721

5400 565.4866776 10.00812968 0.175948545 0.002653828 2.1113825 1.500704482

5600 586.4306287 10.37880115 0 -

0.000460155 0 0

rpm Ta+Td (Total Applied

Load, mN-m) Kt*I

eff (%)

130 18.38348745 0.018383 0.019575

250 18.03579474 0.018036 0.037626

290 17.91989717 0.01792 0.043639

400 17.60117886 0.017601 0.060163

475 17.38387092 0.017384 0.07142

590 17.05066542 0.017051 0.088664

640 16.90579346 0.016906 0.096155

715 16.68848552 0.016688 0.107384

750 16.58707515 0.016587 0.112621

840 16.32630562 0.016326 0.126078

Page | 32

885 16.19592086 0.016196 0.132802

960 15.97861292 0.015979 0.143999

1010 15.83374096 0.015834 0.151458

1100 15.57297143 0.015573 0.164871

1360 14.81963724 0.01482 0.203525

1600 14.12425184 0.014124 0.239064

1800 13.544764 0.013545 0.268559

2000 12.96527616 0.012965 0.29793

2500 11.51655657 0.011517 0.370688

2700 10.93706873 0.010937 0.399461

2800 10.64732481 0.010647 0.41376

2900 10.35758089 0.010358 0.427996

3000 10.06783697 0.010068 0.442162

3200 9.488349133 0.009488 0.47026

3400 8.908861295 0.008909 0.497995

3600 8.329373457 0.008329 0.525291

3800 7.749885619 0.00775 0.552049

4000 7.170397781 0.00717 0.57814

4200 6.590909943 0.006591 0.603387

4400 6.011422105 0.006011 0.627546

4600 5.431934267 0.005432 0.650269

4800 4.85244643 0.004852 0.671042

5000 4.272958592 0.004273 0.689071

5200 3.693470754 0.003693 0.703064

5400 3.113982916 0.003114 0.710769

5600 0 0 0

Generator Data

rpm ω(rad/sec) Vb (Volts) I (Amps) Ta (N-m) P_in (W) P_out (W)

0 0 0 0 0 0

130 13.61356817 0.284563871 0.013346801 -0.00022394 -0.003049 0.001781371

250 26.17993878 0.547238213 0.025666925 -5.89485E-06 -0.000154 0.00658791

290 30.36872898 0.634796327 0.029773633 6.67867E-05 0.0020282 0.008864692

400 41.88790205 0.875581141 0.04106708 0.000266661 0.0111699 0.016865051

475 49.74188368 1.039752605 0.048767158 0.000402939 0.0200429 0.023782357

590 61.78465552 1.291482183 0.060573943 0.000611899 0.0378059 0.036692026

640 67.02064328 1.400929826 0.065707328 0.000702751 0.0470988 0.04317453

715 74.87462491 1.56510129 0.073407406 0.000839029 0.0628219 0.053886472

750 78.53981634 1.641714639 0.077000775 0.000902625 0.070892 0.059291194

Page | 33

840 87.9645943 1.838720396 0.086240868 0.001066158 0.0937842 0.074374873

885 92.67698328 1.937223274 0.090860915 0.001147925 0.1063863 0.082557058

960 100.5309649 2.101394738 0.098560992 0.001284203 0.1291022 0.097142692

1010 105.7669527 2.210842381 0.103694377 0.001375055 0.1454354 0.107525239

1100 115.1917306 2.407848138 0.11293447 0.001538589 0.1772327 0.127541946

1360 142.418867 2.976975879 0.139628072 0.002011019 0.2864071 0.194959986

1600 167.5516082 3.502324564 0.16426832 0.002447109 0.410017 0.26984081

1800 188.4955592 3.940115134 0.18480186 0.002810516 0.5297699 0.341517276

2000 209.4395102 4.377905705 0.2053354 0.003173924 0.6647452 0.421626266

2500 261.7993878 5.472382131 0.25666925 0.004082444 1.0687814 0.658791041

2700 282.7433388 5.910172702 0.27720279 0.004445852 1.2570351 0.76841387

2800 293.2153143 6.129067987 0.28746956 0.004627556 1.3568703 0.826387482

2900 303.6872898 6.347963272 0.29773633 0.00480926 1.4605111 0.886469225

3000 314.1592654 6.566858557 0.3080031 0.004990964 1.5679576 0.948659099

3200 335.1032164 7.004649128 0.328536641 0.005354372 1.7942672 1.079363242

3400 356.0471674 7.442439698 0.349070181 0.00571778 2.0357993 1.218499909

3600 376.9911184 7.880230269 0.369603721 0.006081188 2.2925537 1.366069103

3800 397.9350695 8.318020839 0.390137261 0.006444596 2.5645306 1.522070821

4000 418.8790205 8.75581141 0.410670801 0.006808003 2.8517298 1.686505065

4200 439.8229715 9.19360198 0.431204341 0.007171411 3.1541515 1.859371834

4400 460.7669225 9.631392551 0.451737881 0.007534819 3.4717955 2.040671129

4600 481.7108736 10.06918312 0.472271421 0.007898227 3.8046619 2.230402948

4800 502.6548246 10.50697369 0.492804961 0.008261635 4.1527507 2.428567294

5000 523.5987756 10.94476426 0.513338501 0.008625043 4.516062 2.635164164

5200 544.5427266 11.38255483 0.533872041 0.008988451 4.8945956 2.85019356

5400 565.4866776 11.8203454 0.554405581 0.009351859 5.2883516 3.073655481

5600 586.4306287 12.25813597 0.574939121 0.009715267 5.69733 3.305549927

rpm T_input (mN-m) Kt*I

eff (%)

0 0.460155 0.00046 0

130 0.696369875 0.000236 -0.58432

250 0.914414621 0.000454 -42.6881

290 0.987096203 0.000527 4.370658

400 1.186970553 0.000727 1.509869

475 1.323248519 0.000863 1.18657

590 1.532208068 0.001072 0.970536

640 1.623060045 0.001163 0.91668

715 1.759338011 0.001299 0.857765

750 1.822934395 0.001363 0.836359

840 1.986467955 0.001526 0.793043

Page | 34

885 2.068234734 0.001608 0.776012

960 2.2045127 0.001744 0.752448

1010 2.295364678 0.001835 0.739333

1100 2.458898237 0.001999 0.71963

1360 2.93132852 0.002471 0.680709

1600 3.367418011 0.002907 0.658121

1800 3.730825921 0.003271 0.644652

2000 4.094233831 0.003634 0.634268

2500 5.002753605 0.004543 0.616395

2700 5.366161515 0.004906 0.611291

2800 5.547865469 0.005088 0.609039

2900 5.729569424 0.005269 0.606958

3000 5.911273379 0.005451 0.605029

3200 6.274681289 0.005815 0.601562

3400 6.638089198 0.006178 0.598536

3600 7.001497108 0.006541 0.595872

3800 7.364905018 0.006905 0.593509

4000 7.728312927 0.007268 0.591397

4200 8.091720837 0.007632 0.5895

4400 8.455128747 0.007995 0.587786

4600 8.818536657 0.008358 0.586229

4800 9.181944566 0.008722 0.584809

5000 9.545352476 0.009085 0.583509

5200 9.908760386 0.009449 0.582314

5400 10.2721683 0.009812 0.581212

5600 10.6355762 0.010175 0.580193

D.4. Turbine Flow Analysis

rpm w abs(Power) efficiency Torque

r1 0.01905 m 0 0 0 0 0

r2 0.01905 m 100 10.47198 1.321070184 0.016879491 0.372423

v1 23.4 m/s 200 20.94395 2.642140369 0.033758982 0.186211

v2 0 m/s 300 31.41593 3.963210553 0.050638472 0.124141

400 41.8879 5.284280737 0.067517963 0.093106

vdot 0.000283 m^3/s 500 52.35988 6.605350921 0.084397454 0.074485

p 1000 kg/m^3 600 62.83185 7.926421106 0.101276945 0.06207

700 73.30383 9.24749129 0.118156436 0.053203

800 83.7758 10.56856147 0.135035927 0.046553

max power 78.26481 watts 900 94.24778 11.88963166 0.151915417 0.04138

Page | 35

Assumed Efficiency 0.05 1000 104.7198 13.21070184 0.168794908 0.037242

Actual Power 3.913241 1100 115.1917 14.53177203 0.185674399 0.033857

1200 125.6637 15.85284221 0.20255389 0.031035

1300 136.1357 17.1739124 0.219433381 0.028648

1400 146.6077 18.49498258 0.236312872 0.026602

1500 157.0796 19.81605276 0.253192362 0.024828

1600 167.5516 21.13712295 0.270071853 0.023276

1700 178.0236 22.45819313 0.286951344 0.021907

1800 188.4956 23.77926332 0.303830835 0.02069

1900 198.9675 25.1003335 0.320710326 0.019601

2000 209.4395 26.42140369 0.337589817 0.018621

2100 219.9115 27.74247387 0.354469307 0.017734

2200 230.3835 29.06354405 0.371348798 0.016928

2300 240.8554 30.38461424 0.388228289 0.016192

2400 251.3274 31.70568442 0.40510778 0.015518

2500 261.7994 33.02675461 0.421987271 0.014897

2600 272.2714 34.34782479 0.438866761 0.014324

2700 282.7433 35.66889498 0.455746252 0.013793

2800 293.2153 36.98996516 0.472625743 0.013301

2900 303.6873 38.31103534 0.489505234 0.012842

3000 314.1593 39.63210553 0.506384725 0.012414

Page | 36

Appendix E: Bill of Materials for Mass Production

The offset pinwheel design contains the following parts in assembly:

Generator – for electrical generation

Cost = $5.00

This cost estimate was made based on similar generator models found online. Assuming the

Mechanical Engineering department purchases the generators in bulk, a similar price would be

provided on a large manufacturing scale.

Shaft – to translate the torque generated by the water flow

Cost = $0.75

This component will be made of plain carbon steel in order to survive the torque applied by the

pinwheel. Additionally, this cost estimate was made using the current prices of steel rods. The

small dimensions of the shaft (less than a half inch diameter), reduce the price of the component.

Water seals (3) – to prevent leakage and keep the motor assembly dry

Cost = $2.50

These components will be made of plastic and will prevent water from entering the motor area.

These water seals will surround the shaft and be tight against the housing to maintain protection

against leakage. The cost estimate was based on current water seal prices scaled down to the

small dimensions required for this project.

Pinwheel – the powerhouse of the product, a Pelton style turbine

Cost = $14.99

The pinwheel is the most critical piece for the project. Care must be taken during manufacturing

to produce the most efficient design that will utilize power from the water flow most effectively.

Since this portion of the product will be made in the rapid prototyping machine, it is difficult to

estimate the actual manufacturing cost. Using web resources, the team discovered prices of

similar water pinwheels and assumed that the cost would be similar for a smaller design due to

difficulties in manufacturing.

Pinwheel/Generator housing – Metal housing to protect and hold the pinwheel, seals,

shaft, and generator components in place

Cost = $4.00

This piece will be made of 6061 Aluminum for its light weight and strong properties and will be

rectangular in shape. Using current prices for this alloyed aluminum at the specified dimensions

(around 1.25 inches in outer diameter), the team was able to estimate a price.

Page | 37

Flow guide housing – Metal housing to guide the flow to the pinwheel. A threaded

portion of this component connects to the sink faucet.

Cost = $4.00

This piece will be nearly identical to the Pinwheel/Generator housing. It will be made of the

same material, be the same rectangular shape, and have nearly identical dimensions. Therefore,

we applied the same cost estimate to this portion of the design.

Nozzle – To direct the flow to the turbine and increase the kinetic energy of the flow

Cost = $3.50

The nozzle will be an integral part of the product design. It is used to increase the kinetic energy

of the water flow to spin the pinwheel at a higher angular velocity to increase the power

produced. This will be the same material as the 6061 Aluminum housing and will be connected

to the housing with a simple butt weld. Additionally, the top of the nozzle will be threaded in

order to easily connect to the customer’s faucet.

Using the above cost estimates, the overall price for all the components will be $34.74.

However, this price does not take into account manufacturing costs associated with making a

single unit. Although overhead to operate the business does not need to be considered, we

assumed around a 15% manufacturing cost when producing each unit. This brings the new total

cost to $39.95 per unit. Note that this cost estimate does not include marketing costs for

spreading word about the product or labor costs during production.

Finally, using the above total unit cost estimate, it was possible to determine the cost of

producing 100,000 units. In order to produce this volume, it would cost roughly $3.9 million

dollars. Although this cost may seem high, the proposed retail price for the final product is

$50.00 a unit. This would yield around $5 million dollars in gross sales and nearly $1.1 million

dollars in company profit (not accounting for marketing and labor costs).

Page | 38

Appendix F: Economic Analysis for Full Scale

Economic Analysis:

Net Present Value (NPV) is an important economic gauge often applied during project design. It

represents the present worth of the total costs and profits over the period of the project at an assumed

interest rate. The following equation quantitatively expressed NPV:

𝑁𝑃𝑉 = 𝑝𝑒𝑟𝑖𝑜𝑑 𝑐𝑎𝑠𝑕 𝑓𝑙𝑜𝑤

1 + 𝑑𝑖𝑠𝑐𝑜𝑢𝑛𝑡 𝑟𝑎𝑡𝑒 𝑝𝑒𝑟𝑖𝑜𝑑𝑝𝑒𝑟𝑖𝑜𝑑𝑠

𝑁𝑃𝑉 = 𝐶𝑖

1 + 𝑟 𝑖

𝑁

𝑖=1

For calculating NPV, the following assumptions were made:

Interest Rate on costs = 10%

Cost of student labor = $20/hr

Cost of machining labor = $60/hr

Tooling cost per unit = $0.10/unit

Ramp-up cost per unit = $0.10/unit

Marketing and Support Costs = $100/hr for 10 total hours (commercials, paid marketers, etc.)

Manufacturing time = 5 minutes/unit, at machining labor price and $5.00 variable cost per unit

Sales Volume = 100,000 units per year in a 4 year period

The table below displays the above listed costs and their summation excluding the cost of materials for

the project.

Time (hr) Cost/Time

($/hr) Total Time

Cost ($) Variable

Cost/Unit ($/u) Variable Cost Total Total Cost

Development Cost 147.5 20 2950 0 0 2950

Testing Cost 2 20 40 0 0 40

Tooling Investment 0.25 60 15 0.1 40000 40015

Ramp-up Cost 40 20 800 0.1 40000 40800

Marketing and Support Cost 10 100 1000 0 0 1000

Manufacturing Costs 0.0833333 60 4.999998 5 2000000 2000000

Total Costs (excluding materials) 2084805

The table below shows a summary of the above results, includes the retail price, sales volume, and

material cost. Using all of this data, the table calculates the cash flow in a given period (1 year) and the

final Net Present Value for the entire project.

Page | 39

Sales Volume (# of units/year) 100,000 units

Retail Price ($/unit) $50/unit

Revenue ($) 20,000,000

Material Costs 13,896,000

Total Costs 2,084,805

Interest Rate (%) 0.1

Cash Flow (per period) 1,004,798.75

NPV 686,291.0662

Included below is the sample calculation for net present value for the project using 4 periods (1 year each)

and the calculated cash flow per period:

𝑁𝑃𝑉 = 𝐶𝑖

1 + 𝑟 𝑖

𝑁

𝑖=1

=$1,004,798.75

1 + .10 4= $𝟔𝟖𝟔, 𝟐𝟗𝟏. 𝟎𝟕

Page | 40

Appendix G: Dimensioned Drawings of Final Design

Page | 41

Page | 42

Page | 43

Page | 44

Page | 45