team p12442 marissa blockus, brandon harbridge, …edge.rit.edu/edge/p12442/public/system design...

Next Generation Charcoal Stove for Haiti

Team P12442

Marissa Blockus, Brandon Harbridge, Sam Huynh, Brianna Stephenson-Vallot, Dustin Tyler

Team Members

• Brandon Harbridge (IE) – Team Lead, Test Technician

Stove Team • Samantha Huynh (ME) – Lead Engineer

• Brianna Stephenson-Vallot (ME) – Team Engineer,

Purchaser Thermoelectric Team

• Marissa Blockus (ME) – Team Facilitator

• Dustin Tyler (ME) – Team Engineer, EE Liaison

Purpose of Review

• Demonstrate the group’s progress in accepting the tasks involved in creating two functioning Haitian cook stoves

• To gain feedback on the group’s current path to verify that the team has a complete understanding of the project

• Finalize customer Needs/Specs

• To obtain constructive criticism in order to improve as young engineers

Customer Needs-Stove

Need Importance Description Notes

1 9* Affordable (initial cost <$10 at high production) 1-10K Production

2 9 Requires less fuel for same cooking tasks

3 9 Reduced CO emissions

4 9 Safe to operate

5 9 Same or improved cooking controls

6 9 Able to be fabricated and assembled using Haitian artisan practices

7 3 Obtain rapid boil quickly and then bring to simmer

8 3 Easy to operate (l ittle user interaction and intuitive processes)

9 3 Transportable (able to be moved by a single Haitian adult 500 m)

10 3 Rugged (can handle being dropped and withstand harsh conditions)

11 3 Durable - l ifetime of five or more years Used twice a day

12 3 Have simple, cheap and easily replaceable parts

13 3 Reduced PM emissions

Importance Scale: 1 - low importance, 3 moderate importance, 9 high importance

* items are most critical

Engineering Specs-Stove

Eng Spec Description Importance Units Marginal Value Ideal Value

Relates to Customer

Need(s) Notes

1 Cost 9 $ <$15 <$10 1

2 Assembly time 3 hrs < 4 < 2 12,8

3 Fuel reduction 9 kg 50% >50% 2,3

Compared to Haitian

Rebar Stove, WBT and

Simmer

4 CO reduction 9 g 25% >50% 3

Compared to Haitian


Simmer

5 PM reduction 3 g 25% >55% 4

Compared to Haitian


Simmer

6 Time to boil 9 min 22.5 <22.5 7

7 Maximum Surface Temperature 1 °C < °50 C < °40 C 13

8 Time to boil for Modified WBT 3 min < 15 < 8 7,6

9 Range of heat output 3 kW 1 - 6 .8 - 6.2 7

10 Capable pot diameters 3 cm 20 - 60 15 - 65 5,6

11 Withstand pot mass 9 kg 25 30 5,6

12 Five or less tasks to maintain fire 3 tasks 5 < 5 5,6

13 Replacement: Part cost 3 $ 3 < 3 12

14 Replacement: Time required 1 min 60 < 60 8,12

15 Replacement: Tools required 3 - - - 8 Simple Haitian hand tools

16 Stove overall mass 3 kg 8 8 9

17 Stove volume 1 m^3 0.2 < 0.2 1

18 Stove construction 9 - - - 9 Simple Haitian hand tools

19 Survive 20 X 2-meter drop tests 3 drop tests 20 20 10,11


Customer Needs-TEG

Need Importance Description Notes

1 9* Thermoelectric module will not fail

High temperature

gradients as well

as mechnanical

failure

2 9* Maintain appropriate temperature gradient across thermoelectric module

3 9 Safe to operate

4 9 Durable - l ifetime of five or more years Used twice a day

5 3 Rugged (can handle being dropped and withstand harsh conditions)

6 3 Have simple, cheap and easily replaceable parts

7 3 Achieve Desired temperature gradient quickly

TE Team


* items are most critical

Engineering Specs-TEG

Eng Spec Description Importance Units

Marginal

Value Ideal Value

Relates to

Customer Need(s) Notes

1 Survive 20 X 2-meter drop tests 3 drop tests 20 20 1,2

2

Minimum temperature gradient

across Thermonanic TE 9 °C 200 200 6 Under peak conditions

3 Quickly reach temperature gradient 9 min 20 15 7

4 Stove electrical consumption 9 W .6 - 1 <.9 4

5

Maximum thermoelectric

temperature on hot side 9 °C 380 (400) 380 6

380°C continuously and

400°C intermittently

6

Maximum thermoelectric

temperature on cold side 9 °C

(Value from

EE Team) 200 6

7

Thermoelectric module is

mechanically loaded evenly and 9 - - - 6

8 Cost 9 $ <$10 <$10 3,5

TE Team


System Energy Flow-Stove

System Map

Start-Up Flow Diagram

Start fire

Enough power

stored in battery to

run fan

Harvest heat from

combustion chamber to

power TEG

No power stored to

run fan

Convert power

produced by TEG

to power fan

Battery power to

aux device

Turn on fan

Store TEG power

produced in

battery

Process

Takes

longer

Harvest heat from

combustion chamber to

power TEG

Store power to

operate fan at next

start up

Stove/TEG team

EE Team

TEG Diagram 1

TFIRE

Thermoelectric Harvester Heat Sink Thermoelectric Unit (TEG)

W=q1-q2

TH-TC=200°C

α=0.0346 V/K

TEG

qLOSS Re=2.745 Ω

RTH=1.376 K/W

TEG Diagram 2

Delta T 200 degrees C

Tc (C) 100 110 120 130 140 150 160 170 180

Th (C) 300 310 320 330 340 350 360 370 380

Imax 1.26

qh (W) 156.25 156.69 157.12 157.56 158.00 158.43 158.87 159.30 159.74

qc (W) 151.89 152.33 152.76 153.20 153.64 154.07 154.51 154.94 155.38

W (W) 4.36 4.36 4.36 4.36 4.36 4.36 4.36 4.36 4.36

At a temperature difference other than 200C


Tc (C) 100 110 120 130 140 150 160 170 180

Th (C) 225 235 245 255 265 275 285 295 305

Imax 0.788

qh (W) 96.12 96.40 96.67 96.94 97.21 97.49 97.76 98.03 98.30

qc (W) 94.42 94.69 94.97 95.24 95.51 95.78 96.06 96.33 96.60

W (W) 1.70 1.70 1.70 1.70 1.70 1.70 1.70 1.70 1.70


Tc (C) 100 110 120 130 140 150 160 170 180

Th (C) 250 260 270 280 290 300 310 320 330

Imax 0.945

qh (W) 115.96 116.29 116.62 116.94 117.27 117.60 117.92 118.25 118.58

qc (W) 113.51 113.84 114.16 114.49 114.82 115.14 115.47 115.80 116.13

W (W) 2.45 2.45 2.45 2.45 2.45 2.45 2.45 2.45 2.45


Tc (C) 100 110 120 130 140 150 160 170 180

Th (C) 275 285 295 305 315 325 335 345 355

Imax 1.103

qh (W) 136.00 136.39 136.77 137.15 137.53 137.91 138.29 138.68 139.06

qc (W) 132.67 133.05 133.43 133.81 134.19 134.57 134.96 135.34 135.72

W (W) 3.34 3.34 3.34 3.34 3.34 3.34 3.34 3.34 3.34

qh = α*Th*I + K*(Th-Tc) - 1/2*Re*I^2 qc = α*Tc*I + K*(Th-Tc) + 1/2*Re*I^2

Imax = α*(Th-Tc)/(2*Re) W = qh-qc

α 0.035 V/K

Re 2.745 ohms

Rth 1.376 K/W

K 0.7267 W/K

Governing Equations

Measured Constants

What this shows… The heat conduction required from the fire to achieve the hot side temperature as well as the cooling required to maintain the cold side temperature. Though this is a crude representation, it represents a basis for further study.

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

0 50 100 150 200 250

Po

we

r P

rod

uce

d (

W)

Delta T (C)

Power Produced Vs. Delta Temp

Morphological Chart

Functions Option 1 Option 2 Option 3 Option 4

Provide heat to pot Direct Contact Skirt

Combustion chamber

shape/size

Provide complete combustion Fan Swirl Chamber

Combustion chamber

shape/size

Convert heat into electricity TEG

Provide air to stove fire 1 Fan Multiple Fan Compressed air source Natural Draft

Control air flow Fan Speed Adjustable bypass Duct sizing Throttling

Provide heat to hot side of TEG Direct contact Extended metal surface Contact Block Radiative

Control temp at the hot side of the TEG Fan control Extended metal surface sizing Insulate around TEG

Provide cooling to cold side of TEG Heat sink Forced Convection (fan) Liquid Cooling

Control temp at the cold side of the TEG Sizing of heat sink Fan control Type of liquid used Fan overall size

Control temp gradient across TEG Modify extended surface Direct mount

Achieve temp difference within 20 min Extended surface sizing Fan control (or number of fans)

Extended surface location

within combustion chamber

Connect/disconnect harvester from stove Bolts Dowels

Associated Risks

System, Materials and Manufacturing, TEG, Fan and Conducting Rod Risks

ID Risk Item Effect Cause

Lik

elih

oo

d

Sev

erit

y

Imp

ort

an

ce

Action to Minimize Risk Owner

Describe the risk briefly

What is the effect on any or all

of the project deliverables if the

cause actually happens?

What are the possible

cause(s) of this risk?L*S

What action(s) will you take (and by when) to

prevent, reduce the impact of, or transfer the

risk of this occurring?

Who is

responsible for

following

through on

mitigation?

1 Stove not easily repaired. Life of stove can be altered.Designed as a one piece

system.2 1 2

Design pieces with a high potential of breaking

to be easily removed.Bri

2Does not meet emissions

goal.Cannot be used indoors. Insufficient stove design. 2 3 6

Ensure complete combustion of fuel is

obtained.Sam

3Does not meet high efficiency

goal.Stove needs to be redesigned. Insufficient stove design. 2 3 6 Heat transfer to pot must be maximized. Bri/Sam

4Insufficient interaction with

electrical team.

Stove does not meet needs or

specs.

Don't consult the other

team.2 2 4

Maintain consistent communication with the

other team.Dustin

5Heat output by stove is not

adjustable.

Stove will resemble current

stoves.

Did not take customer

needs into consideration.3 2 6

Ensure there is a means of adjusting the flow

(i.e. flap, fan).Bri

6 Inaccurate testing data.Insufficient redesign of areas in

need.

Data does not collect or

does not match last

year's.

3 2 6

Test until appropriate data is received.

Contact previous year group members if

issues continue to occur.

Brandon

7 Transient modeling.Forced induction may fail at

start-up/batter is drained.

Insufficient transient heat

transfer modeling.

Insufficient energy

storage capabilities

3 2 6

Rigorous transient heat transfer analysis.

Careful selection of heat transfer method.

Extensive testing.

Bri/Sam

8Casing conducts too much

heat.Jeopardize user safety Insufficient insulation 2 3 6

Testing of radiant and conductive heat transfer

in casing.Brandon

Risks Associated with System/Project Management

1-low likelihood/severity, 2-moderate likelihood/severity, 3-high likelihood/severity


Lik

elih

oo

d

Sev

erit

y

Imp

ort

an

ce


9 Material cost is too high.

Will not be able to be

manufactured or marketed in

Haiti.

Designed with resources

unavailable to Haitians.

Excessive component

costs.

3 2 6 Ensure materials are locally available in Haiti. Sam

10Stove too heavy and not

mobile.Cannot be marketed to vendors.

Overlooked customer

mobility need.2 3 6 Final product must be made of light materials Sam

11Cannot be manufactured

within Haitian abilities.Stove cannot be built in Haiti.

Complex components and

exotic manufacturing

methods (CNC).

2 3 6Consider means of production when in design

process.Sam

12Materials unavailable for

prototype stove.

Cannot build or test a stove

with the correct materials.

Materials are unavailable

to us or are ordered too

late. In sufficient

consideration given to

lead times.

2 3 6Do not delay in ordering the materials. Plan

ahead for lead times.Bri

Risks Associated with Materials and Manufacturing



Lik

elih

ood

Sev

erit

y

Imp

ort

an

ce


13 TEG Overheat. Total system failure.Inadequate heat transfer

control.2 3 6

In-depth heat transfer analysis including FEM

and testing.

Marissa/

Dustin

14 Insufficient TEG cooling. Unsustainable operation.Heating up of TEG cold

side.2 2 4 In-depth heat transfer analysis of heat sink.

Marissa/

Dustin

15Inability to accurately model

TEG

Optimal power output not

realized.

TEG model changes with

heat and current. Load

resistance is effected.

2 2 4In depth analysis of the TEG unit as well as

modeling and testing.

Marissa/

Dustin

16Insufficient TEG power

production capability.Underpowered system.

Unable to meet required

temperature difference

across TEG. TEG

maximum output too

small

2 3 6In depth heat transfer analysis and testing of

TEG system.

Marissa/

Dustin

17

Temperature gradient across

hot side of the thermoelectric

unit.

Underpowered system.

Low conduction material

used. Insufficient analysis

done of the rod.

3 2 6Detailed heat transfer analysis of the rod

holding the TEG. Add an angle down the rod.Marissa

18Inaccurate benchmarking at

the thermoelectric region.

Insufficient data used as a

reference to redesign the

thermoelectric region

Thermocouples not

placed appropriately.3 2 6

Contact the old team to understand their

placement. Add more thermocouples in the

appropriate locations to collect better data.

Dustin/Brandon

Risks Associated with Thermoelectric (TEG)



Lik

elih

oo

d

Sev

erit

y

Imp

ort

an

ce


19

Fan does not supply

sufficient supply of air.

Insufficient pressure drop

produced.

Force air system will not work/

reach combustion chamber.

Analysis of air flow was

incorrect. Poor modeling/

testing.

1 3 3Theoretical airflow analysis must include

potential losses. Marissa

20 Fan melts. Loss of airflow. System failure.

Fan placed too close to

stove. Underestimation of

stove temperature.

1 3 3Testing/benchmarking to correctly estimate

temperatures at proposed locations.

Dustin/

Brandon

21 Fan requires too much power

Fan will drain power from

battery. TEG will be unable to

provide enough power and

system will fail.

Poor fan selection or

design. Lack of

communication with

Electrical team.

1 2 2Contact electrical team to ensure selected fan

fits within their proposed system.Dustin

Risks Associated with Fan



Lik

elih

oo

d

Sev

erit

y

Imp

ort

an

ce


22Heat conduction rod/ device

melting.

Possible loss of heat conduction

to TEG.

Inadequate analysis of

stove temperatures and

material properties.

2 3 6

Analyze stove operating temperatures. Select

materials to suit/withstand those

temperatures.

Marissa/Dustin

23

Heat conduction device

conducts too much/too little

heat.

Overheating of TEG or

insufficient power generation.

Inadequate heat transfer

analysis.2 3 6

Complete analysis of heat transfer

characteristics of device. Average stove

operating temps should be considered.

Marissa/Dustin

24Rod takes too long to heat

up.

Improper system function. Fan

may not operate at start-up.

Inadequate heat transfer

analysis. Inadequate

understanding of transient

temperatures in

combustion chamber.

2 2 4

Test stove to gain understanding of transient

temperatures. Complete transient modeling of

rod. Potentially move rod closer to fire/higher

up.

Dustin/

Brandon

Risks Associated with Conduction Rod


Pugh Charts

Stove Team

CriteriaDirect

Contact

Skirt

(reference)

Combustion

Chamber

Size/Shape

Cost 0 0 0

Complexity + 0 -

Life-Span + 0 +

Durability - 0 +

Safety - 0 0

Efficiency - 0 0

Functionality - 0 0

Net Score -2 0 1

Use? No Yes Potentially

Provide Heat to Pot

CriteriaSwirl

Chamber

Fan

(reference)

Combustion

Chamber

Size/Shape

Cost + 0 +

Complexity - 0 -

Life-Span 0 0 0

Durability 0 0 0

Safety 0 0 0

Efficiency - 0 0

Functionality 0 0 0

Net Score -1 0 0


Provide Complete Combustion

Pugh Charts

TE Team

Criteria1 Fan

(reference)Multiple Fans

Compressed Air

Source

Cost 0 - -

Complexity 0 - -

Life-Span 0 0 -

Durability 0 0 -

Safety 0 0 -

Efficiency 0 - 0

Functionality 0 0 0

Net Score 0 -3 -5

Use? Yes Potentially No

Provide Air to Stove Fire

Criteria Fan Speed

Adjustable

Bypass

(reference)

Duct Sizing Throttling

Cost - 0 0 -

Complexity - 0 0 -

Life-Span 0 0 + -

Durability 0 0 0 -

Safety 0 0 + -

Efficiency + 0 + +

Functionality 0 0 0 +

Net Score -1 0 3 -3

Use? No Yes Yes No

Control Air Flow

CriteriaDirect

Contact

Extended

Metal Surface

(reference)

Contact Block Radiative

Cost + 0 + +

Complexity - 0 - -

Life-Span - 0 - 0

Durability 0 0 0 0

Safety 0 0 0 0

Efficiency + 0 + 0

Functionality - 0 - -

Net Score -1 0 -1 -1

Use? No Yes No No

Provide heat to hot side of TEG

Criteria Fan Control

Extended

Metal Surface

Sizing

(reference)

Insulate Around

TEG

Cost - 0 -

Complexity - 0 0

Life-Span 0 0 -

Durability 0 0 0

Safety - 0 0

Efficiency + 0 0

Functionality 0 0 +

Net Score -2 0 -1


Control temp at the hot side of TEG

CriteriaHeat Sink

(reference)

Forced

Convection

(reference)

Liquid Cooling

Cost 0 0 -

Complexity 0 0 -

Life-Span 0 0 -

Durability 0 0 0

Safety 0 0 0

Efficiency 0 0 +

Functionality 0 0 0

Net Score 0 0 -2

Use? Yes Yes No

Provide cooling to cold side TEG

CriteriaSizing of Heat

SinkFan Control Type of Liquid Used

Sizing of

Fan

(reference)

Cost 0 - - 0

Complexity 0 - - 0

Life-Span + 0 0 0

Durability + 0 0 0

Safety 0 - 0 0

Efficiency + + + 0

Functionality + 0 0 0

Net Score 4 -2 -1 0

Use? Yes No No Yes

Control temp at the cold side of TEG

Criteria

Modify

Extended

Surface

Direct Mount

Cost + +

Complexity + +

Life-Span + +

Durability 0 0

Safety + -

Efficiency + +

Functionality 0 0

Net Score 5 3

Use? Yes No

Control Temp Gradient Across TEG

Criteria

Extended

Surface

Sizing

Fan Control (or

Number of

Fans)

Extended Surface

Location within

Combustion

Chamber

Cost + 0 +

Complexity + - +

Life-Span + 0 +

Durability 0 0 0

Safety + - +

Efficiency + + +

Functionality 0 0 0

Net Score 5 -1 5

Use? Yes No Yes

Achieve Temp Difference within 20 min

Project Plan

Task Start Finish Predecessor Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 Week 10

Generate Preliminary Work Break Down 12/5/2011 12/9/2011 N/A

Plan for Weeks 3,4,5 12/5/2011 12/9/2011 N/A

Identify Customer Needs 12/5/2011 12/9/2011 N/A

Identify Engineering Specs 12/5/2011 12/9/2011 N/A

Generate Block Diagram/System

Configuration12/5/2011 12/9/2011 N/A

Identify Top 10 Risks 12/5/2011 12/9/2011 N/A

Test Rebar Stove 12/8/2011 12/8/2011 N/A

Test Rebar Stove Again 12/11/2011 12/11/2011 5

Test Last Years Stove 12/14/2011 12/14/2011 6

Learn about Post Processing 12/9/2011 1/1/2012 N/A

Read All Info 11/29/2011 1/1/2012 N/A

Present Planning Presentation 12/9/2011 12/16/2011 1,2,3,4

Generate Concept Development 12/9/2011 12/9/2011 3

Complete Peer Evaluation 1 12/15/2011 12/16/2011 N/A

Update and map Needs/Specs 12/15/2011 12/15/2011 2

Update Block Diagram 12/15/2011 12/15/2011 3

Update Risks/Mitigations 12/15/2011 12/16/2011 4

Generate Concept Matrix 12/15/2011 12/16/2011 11

Identify Key Functions 12/15/2011 12/16/2011 14

Evaluate/Generate Risk Assessment 12/17/2011 1/12/2012 11,12

Morphographical Chart/ Function

Breakdown Chart1/12/2012 1/13/2012

Update Block Diagram 1/12/2012 1/13/2012

Update Needs/ Specs Relationship 1/12/2012 1/12/2012 13

Present Practice System Design

Review1/13/2012 1/13/2012 10

Present System Design Review 1/20/2012 1/20/201218, 19, 10,

23

Complete any action items from system

design review and continue working on

flow diagrams

1/20/2012 6.7

Select Final Concept 11

Evaluate Risk Management 19

Develop and Follow Through with Test

Plans21

Create Bill of Materials 22

Present Detailed Design Review20, 22, 23,

24, 25

Work Breakdown Structure

Brandon Harbridge:

Project Manager,

Edge Guy

|

Sam Huynh: Lead

Engineer, Design

Specialist

/ | \

Marissa Blockus:

Team Facilitator,

3D Modeling

Dustin Tyler: Pairing

with EE Team (Fan

& Thermoelectrics)

Brianna

Stephenson- Vallot:

Testing Guru,

Purchaser

Stove Team

TEG Team

Future Plans

• Detailed heat transfer analysis of proposed heat harvesting

system to determine appropriate heat sink and conduction rod

sizing.

• Calculate all percentage heat losses within the stove system to

better optimize future designs.

• Analyzing the need for a change in combustion chamber

geometry.

• Test existing RIT stove to compare empirical data with

theoretical models and determine overall efficiency of the

system.

Questions?

team p12442 marissa blockus, brandon harbridge, …edge.rit.edu/edge/p12442/public/system design...

Documents