project 13441: cook stove for haiti

Project 13441: Cook Stove for Haiti

Agenda

• Team Introduction

• Project Statement

• Project Goals

• Key Customer Needs and Specifications

• System Architecture

• Concept Summary

• Testing and Test Results

• Final Bill of Materials

• Final Prototype

• Results vs. Specifications

• Lessons Learned

• Suggestions for Future Work

Guide and Team Members

Guide

• Sarah Brownell

Customer

• Dr. Robert Stevens

Team Members

• Kim Hunt, ISE (Project Manager)

• Andrew Rietz, ME

• Matt Starowitz, ME

• Tyler Smith, ME

• Matt Aloisio, EE

• Biruk Kifle, EE

Project Statement

The goal of this project is to build on the work done by previous projects P10461, 11461, 11462, 12441, and 12442 to design and fabricate an improved thermoelectric charcoal cook stove that will substantially reduce the emissions and fuel needed for cooking compared to the traditional stoves currently used in Haiti and is also capable of charging cell phones.

Project Objectives

The stove was designed to improve the quality of life for Haitians by:

• Reducing the cost of cooking by reducing the fuel use by 25%

• Reducing the CO emissions and particulate matter (PM) by 25%

• Allowing locals to easily manufacture and sell the stove

• Being intuitive and enhance conventional Haitian cooking techniques

• Providing an electrical power source capable of charging cell phones

• Improving air quality by reducing harmful emissions and particulates

Importance Level 9 Importance Level 3 Importance Level 1

- Affordable for Haitians

- Cheap to operate - Cleaner emissions

(CO and particulate matter)

- Safe to operate - Fan can provide force

air during operation - Uses less fuel

(charcoal) than current stove

- Easy to operate - Able to control cooking

ability - Tip resistant - Capable of being dropped - Thermoelectric module

(TEM) can withstand failure - Able to charge cell phones - Fan is capable of restarting - Mains appropriate

temperature gradient across TEM

- Achieves desired temperature gradient quickly

- Capable of being fabricated and assembled using Haitian artisan practices

- Can withstand harsh conditions

- Portable

Key Customer Needs

Key Engineering Specifications Specification Unit of Measure Ideal Value

Production Cost USD <$30

Fuel Use % reductions in kg >25%

CO Emissions % reduction in ppm >25%

Particulate Matter (PM) % reduction in grams >25%

Minimum temp. gradient for TEM

°C >200°

Pot diameters to be placed on stove

cm 60

Cell phones charged # of phones 2

Stove Weight kg <8

Surfaces touched by operator

°C <50°

System Architecture

Concept Summary - ME

Concept Summary - ME

Combustion chamber

Where pot sits

Fan

TEM

Cold air chimney

Hot air chimney

Skirt

Insulation

Concept Summary - EE

Testing - ME

• 6 Modified Water Boil Tests were performed

• Hot side chimney temperature

• Hot side heat sink temperature

• Cold side heat sink temperature

• TEM output voltage

Testing - ME

Testing - EE

• Adjustable PWM Fan Control

• High/Low Voltage Cut Off

• USB Output

Test Results - EE

• Adjustable PWM Fan Control

25KHz @ 45% Duty Cycle 25KHz @ 65% Duty Cycle

Test Results - EE

• High/Low Voltage Cut off

On state Shut off at 5.75V

Test Results - EE

• USB Output

5V with 6V input 5V with 7.6V input

Test Results - EE

• Timing Circuit (Vtc1 & Vtc2)

Test Results - EE

• Half voltage tracking output

Test Results - EE

• MPPT out in relation to various input

4.2V input with 7.24V output 6.73V input with 7.25V

output

Final Bill of Materials - ME

ME Total Price: With Steel = $75.43

W/O Steel = $38.58

* Prices for handles not included

Component Value Manuf Manuf Part NoQty per

Stove

Parts /

UnitUnit Price

Price per

1k Parts

Price per

Stove

Fan 50 Pa Sanyo Denki USA 9GA0412P6G001 1 14.28$ 14.28$

Heat Sink 0.6 resistanceBirmingham

Aluminum8052HS 2 2 32.47$ 4.72$ 9.44$

Steel Sheet Metal 4'x8' Metals Depot S116 18.1 32 65.28$ 36.92$

Steel tubing 1" x 1" Home Depot 12" 48" 4.00$ 4.00$

TEM 40mm x 40mm Thermonanic TE TEP1-1264-1.5 1 1 8.00$ 8.00$ 8.00$

Duct Bolt 3/8" - 16 McMaster Carr 91309A622 4 100 7.56$ 0.30$

Duct Nut 3/8" - 16 McMaster Carr 93827A225 4 100 13.11$ 0.52$

Rigid Insulation 1.65"x1.97" Cotronics Corp 360-5HS 2 264 130.00$ 0.98$ 1.96$

Total 75.43$

Final Bill of Materials - EE Component Package Value Manuf Manuf Part No Distrib Distrib Part No Qty Price per 1k Price per board

Resistor 0603 SM 4M Stackpole Electronics Inc RMCF0603JT4M0 Digikey RMCF0603JT4M0CT-ND 1 0.01$ 0.01$

Resistor 0603 SM 4.12M Stackpole Electronics Inc RMCF0603JT4M12 Digikey RMCF0603JT4M12CT-ND 1 0.01$ 0.01$

Resistor 0603 SM 33.2k Stackpole Electronics Inc RMCF0603JT33K2 Digikey RMCF0603JT33K2CT-ND 1 0.01$ 0.01$


Resistor 0603 SM 3.32M Stackpole Electronics Inc RMCF0603JT3M32 Digikey RMCF0603JT3M32CT-ND 1 0.01$ 0.01$




Resistor 0603 SM 10k Stackpole Electronics Inc RMCF0603JT10K0 Digikey RMCF0603JT10K0CT-ND 1 0.01$ 0.01$



Resistor 0603 SM 500 Stackpole Electronics Inc RMCF0603JT500R Digikey RMCF0603JT500RCT-ND 1 0.01$ 0.01$





Capacitor 0404 TH 22u Panasonic Electronic Components ECA-1HM220I Digikey P10426TB-ND 1 0.04$ 0.04$


Capacitor 0404 TH 10u Panasonic Electronic Components ECA-1HM100I Digikey P10425TB-ND 3 0.03$ 0.09$

Capacitor 0402 SM 39p Yageo CC0402JRNPO9BN390 Digikey 311-1009-2-ND 1 0.10$ 0.10$

Capacitor 0404 TH 100u Panasonic Electronic Components ECA-1AM101I Digikey P10404TB-ND 4 0.03$ 0.12$

Capacitor 0402 SM 0.1u Yageo CC0402KRX7R7BB104 Digikey 311-1047-1-ND 2 0.10$ 0.20$

Push button TH C&K Components PS12F91AF3.3NS Digikey PS12F91AF3.3NS-ND 1 0.26$ 0.26$

Inductor SM 10u Abracon Corporation AIML-0603-100K-T Digikey 535-11587-1-ND 4 0.07$ 0.28$

Capacitor 0402 SM 0.01u Yageo CC0402KRX7R7BB103 Digikey 311-1042-1-ND 3 0.10$ 0.30$

LM317 TH Texas Insturments LM317KCS Digikey 296-13869-5-ND 1 0.32$ 0.32$

Cap Alum TH 68u Panasonic Electronic Components ECE-A0JKG680 Digikey P903-ND 2 0.26$ 0.52$

Diode TH ON Semiconductors MR852RLG Digikey MR852RLGOSTR-ND 6 0.09$ 0.54$

Pot Rotary 1k Bourns Inc PDB181-K420K-102B Digikey PDB181-K420K-102B-ND 1 0.79$ 0.79$

Gate Driver SM Texas Insturments UCC27517DBVR Digikey UCC27517DBVR-ND 2 0.65$ 1.30$

LM2621 8-MSOP Texas Insturments LM2621MM/NOPB Digikey LM2621MM/NOPBTR-ND 2 0.73$ 1.46$

555 Timer 8-SOIC Texas Insturments NA555PE4 Digikey NA555PE4-ND 4 0.11$ 0.44$

N-channel FET TH STMicroelectronics STP16NF06 Digikey 497-2766-5-ND 5 0.35$ 1.75$

Inductor TH 1mH Bourns Inc 2300LL-102-V-RC Digikey 2300LL-102-V-RC-ND 1 3.75$ 3.75$

Battery 6 Universal Power UB645 batts.com UPG-D5733-BTX-92927 1 5.22$ 5.22$

MAX8211 8-DIP Maxim Integrated MAX8211CPA+ Digikey MAX8211CPA+-ND 3 1.81$ 5.43$

Total $23.17

EE Total Price: $23.17

Final Bill of Materials – ME+EE

Total Price:

ME With Steel = $75.43

EE Comp. = $23.17

$98.60

ME W/O Steel = $38.58

EE Comp. = $23.17

$61.75

* Prices for handles not included

Final Prototype - ME

Final Prototype - EE

Results vs. Specifications Source Specification

Unit of Measure

Marginal Value

Ideal Value Results

S1 CN1 Production Cost USD $ 30 <30 $98.60/$61.75

S2 CN2 Fuel Use % reduction 25 >50 -13.30%

S3 CN3 CO Emissions % reduction 7525 >75 33%

S4 CN3 Particulate Matter (PM) % reduction 25 >75 -147.70%

S5 CN4, CN20 Time to Boil for WBT time current time <3/4 current

time 26.60%

S6 CN16 Surfaces on the stove that the operator has to touch

°C 50 <50 No

S8 CN4 Heat output range (heat transferred to TEM) J 175-200 200 Yes

S9 CN20 Pot diameters to be placed on stove cm 20-60 20-60

S10 CN20 Pot mass to be placed on stove kg 25 >25 Yes

S11 CN4 Required tasks to maintain fire throughout a CCT tasks 5 or less Yes

S12 CN1, CN2 Cost of combustion chamber to be replaced within 3 yr stove life

USD $ 3 <3 No

S13 CN6 Time required to replace parts (within 3 yr stove life)

min 60 <60 No

S14 CN6 Replaceable parts able to be replaced with no or simple hand tools

Yes/No Yes Yes

S15 CN7, CN16,

CN21 Stove weight kg 8kg <8 23

S16 CN7 Stove volume m3 0.2 <0.2 No

S17 CN6 Stove construction should be able to be done using basic Haitian fabrication skills and tools

% 50 100 Yes

Results vs. Specifications

S18 CN11 Drop test (height and quantity) meter/# of

drops 2 &20 >2 or 20 n/a

S19 CN5 Water Temperature during Simmer Test °C 82-92 92-94 No

S20 CN19 Charge cell phones and battery mAh No

S21 CN14 Fan is on during entire stove operation Yes/No Yes Yes n/a

S22 CN13 Power generated for cell phones Wh 8 n/a

S23 CN15 Power for fan to restart following battery shortage

V n/a

S24 CN7,

Internal Power pack package size inches 3"x3"x1.5" n/a

S25 CN7,

Internal Power pack weight lbs 3 <3 n/a

S26 CN8, CN12 Water resistance spec (prevent damage during downpour)

min 20 30 n/a

S27 CN10, CN16 Stove resistance to being knocked over including pot with water on stove

lbs 5 10 Yes

S28 CN10 Stove resistance to tipping over due to unequal weight distribution on top of stove (i.e. pot too far to one side)

lbs 5 10 Yes

S29 CN13 Uses a standard USB connection Yes/No 5V Yes Yes Yes

S30 CN17 Minimum temperature gradient °C 200 >200 Yes

S31 CN18 Time to reach temperature gradient min 20 <20 Yes

S32 Internal Power consumption to operate fan Watt 1 <0.6 Yes

S33 CN12 Max thermoelectric module temperature °C 380 Yes

S34 CN12 Max thermoelectric module temperature difference

°C 400 Yes

S35 CN12 Ideal minimum thermoelectic module temperature

°C 200 200 Yes

S35 CN22 Fuel Capacity in Combustion Chamber kg 1 >1 1

Lessons Learned - EE

• The need for gate drivers • Inductor with higher current rating • Heat sink for high switch power FETs • putting all test equipment on the appropriate

setting • Need for adequate dead time in timing circuit • Testing over entire range of expected operation

Lessons Learned - ME

• Convective heat transfer works

• Proper sandwiching of TEM is important

• Thermal mass makes a big difference

Lessons Learned – ISE/PM

• Order parts early and utilize resources who have experience ordering parts

• Track the progress of the project better compared to what was planned

• Especially during the building phase

• Keep better meeting notes and document group decisions made

Recommendations

• Use uController !!!

• start early with design and procedure. Will need the time for debugging.

• Find someone with background knowledge on MPPT or related topic (solar systems . . . maybe)

• Don't reinvent the wheel. Use the already tested and working subsystems and focus energy into areas that need improvement.

Recommendations

• Better air circulation

• Smaller stove

• Find a better way to sandwich TEM

project 13441: cook stove for haiti

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