Cook Stove for Haiti Enhancements

System Level Design Review

Friday, January 14th 2011

11:00 AM – 12:30 PM

Project 11461

Team Members

Project LeaderRob Reid (ME)

Lead EngineerJordan Hunter(ME)

Team EngineersAlex Seidel (ME)

Brian Knight (ME)Mike Lagos (IE)

Presentation Overview

• Project Background• Project Overview• Work Breakdown• Functional Decomposition• Customer Needs• Engineering Specifications• System Architecture• System Integration• Risk Assessment• Design Concepts• Project Plan

Traditional Cook Stove

Project Background

• The World Health Organization estimates 3 billion people use biomass cooking regularly.

• Approx. 1.5 million people die each year from stove emissions

• Our main focus is the people of Haitiwho’s main method of cookingis open flame stoves, utilizing charcoaland wood.

• We are partnering with the H.O.P.E. Organization, which works with the Haitian people to help improve theirliving conditions and save lives.

• H.O.P.E. is working with RIT to create an improved cook stove designwhich is more efficient and lesshazardous to its users. Image from feaststl.com shows a basic lump charcoal cooking stove

Project Overview

Mission StatementDesign and construct all mechanical and structural aspects of a thermoelectric biomass cook stove.

The stove will utilize a blower/fan powered by thermo-electrics to significantly increase efficiency and reduce fuel consumption and emissions.

In comparison with current Haitian stoves, the project stove will have a reduction in emissions and required fuel of 50%

Deliverables• An improved RIT stove design that has been tested and validated using a working

prototype.• The improved stove is to reduce fuel use and emissions by more than 50% from traditional Haitian stoves. • Build at least two prototype stoves to be sent to Haiti for field testing.• Detailed project report.• Detailed presentation for Imagine RIT.

Work Breakdown

* Everyone Participates in Stove Design and Key Design Decisions in each subsystem.

Functional Decomposition

Customer Needs

Customer Need #

Importance Description Comments/Status

CN1 1 Quick to start Better than existingCN2 1 Reaches boiling rapidly Better than existingCN3 2 Able to reduce thermal power to simmer CN4 1 Accommodates cookware of Vendor & Haitians CN5 1 Affordable to purchase CN6 1 Affordable to operate CN7 2 Easy to operate CN8 2 Intuitive to operate CN9 3 Long life

CN10 2 Durability to withstand typical use, transport, and exposure CN11 2 Repairable - parts swappable and with available skillsets and resources CN12 2 Easy to transport CN13 1 Uses forced air CN14 1 Safe to operate both indoor and outdoor CN15 2 Uses significant less fuel CN16 1 Emits significant less harmful emissions CN17 2 Meet or improve traditional cooking methods CN18 1 Stove can be manufactured using available resourcesCN19 2 Safe and easy removal of unburned charcoalCN20 2 Uses little pumping power for desired airflow <1 watt pumping power

Cust. Need #: enables cross-referencing (traceability) with specificationsImportance: Sample scale (1=must have, 2=nice to have, 3=preference only), or see Ulrich exhibit 4-8.Description: organize as primary and secondary needs (hierarchy) -- Ulrich exhibit 4.8Comment/Status: allows tracking of questions, proposed changes, etc; indicate if you are meeting the need ("met") or not ("not met")

Engineering Specifications

Eng. Spec # Source Specification Marginal Target Unit Comments ES1 CN1 Time to start fire 10 5 min Till specified combustion temperature ES2 CN2 Time to boil 2.5 liters of water after initial start 15 8 min ES3 CN3,13,17 Range of heat output 2.0-6.0 1.0-6.0 kwatts Typical range for single burner stove / Output simmer - fryES4 CN4,17 Range of pot dimensions 20-45 20-60 cm Typical range of pot sizes ES5 CN4,17 Range of pot weights (before deformation) 10 15 kg Weight of full pot before deformation ES6 CN5 Cost 20 <10 dollars Cost @ 1000+ units (est. $1.25 labor/stove & awaiting on pricing from mayor of Borgne)ES7 CN6 Operating cost 0.5 0.25 dollars/day Costs are defined by typical vendor usageES8 CN7,8 Tasks to maintain fire 5 2 Tasks Ex. Adding Fuel, Adjusting Various Parameters ES9 CN9 Stove Life 8 >12 months before repair

ES11 CN10 Cycling without cleaning other than charcoal removal 5 20 cycles i.e. water to clean air inlet, thermoelectic rod or stove baseES12 CN10 Drop test on dirt (w/o damage) 60 100 cm Test : 10 cycles released from typical operation height & handlingES13 CN10 Corrosion area (after 12 months) 0 cm^2 Corrosion from heat or elements - cracks or gaps ES14 CN11 Time to replace parts 90 60 min ES15 CN12,19 Stove volume 0.3 0.2 m^3 Roughly the size of their current stoves. ES16 CN12,19 Stove weight 10 <8 kg Minimize for portability ES17 CN12,19 Lifting Index <15 <10.7 kg Ergonomics - NIOSH Recommended weight lifted - handle testing TBDES18 CN14 CO emissions 20 <10 g emisssions to complete standard WBT (typical stove >40 g)ES19 CN14,16 Hazardous emissions (particulate) <700 <400 mg emisssions to complete standard WBT (typical stove >2200 g)ES20 CN15 Amount of fuel to boil water <20 <15 MJ based on standard WBTES21 CN17 Maximum Temperature 80 50 C Outside Cylindrical Base (prevent serious burns) ES22 CN18 Assembly Time w/ traditional tools 240 120 min Measure of manufacturability - raw materials to complete stove

System Architecture

System Integration(With Thermo-electric team 11462)

11462 (Thermo-Electric) INTERFACE

11461 (Stove) INTERFACE

DEFINING FEATURES

INTERFACE 1Thermo-electric Heat

Rod

Combustion Chamber design and heat flow

characteristics

Heat rod will take energy from fire. Heat

rod will penetrate stove walls.

Diameter of rod

Combustion Chamber Ambient

Temperature

Heat and Air Flow Characteristics

INTERFACE 2 Duct CouplingStove Housing and Forced Air Ducting

Ducting will provide air flow at a given

pressure. Duct will provide air into stove

through duct in the outer wall of stove.

Dimensions of ducting

Location of entrance

Flow Rate Pressure Drop

CRITICAL SPECS

INTERFACE 3 Device Attachment Stove HousingThe fan system will

attach to the outside wall of the stove

Location of device on exterior of

stove

Method of attachment

Architecture of exterior of stove

Surface Temperature of

stove

Risk AssessmentID Risk Item Effect Cause

Likelihoo

d

Severity

Importanc

eAction to Minimize Risk Owner

Describe the risk brieflyWhat 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 Material cost too high.Will not be able to be

manufactured or marketed in Haiti.

Designed with resources unavailable to Haitians. 3 2 6 Ensure materials are locally available in Haiti. Rob

2 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. Michal

3 Combustion will not begin in stove.

Harmful emissions/ less efficient. Improper air flow. 1 3 3 Begin combustion with a fan run by batteries. Alex

4 Does not meet emissions goal. Cannot be used indoors. Insufficient stove design. 2 3 6 Complete combustion of fuel must be obtained. Brian

5 Does not meet high efficiency goal. Stove needs to be redesigned. Insufficient stove design. 2 3 6 Heat transfer to pot must be maximized. Jordan

6 Thermoelectric fan does not supply sufficient supply of air.

Forced air system will not work resulting.

Analysis of air flow was incorrect. Didn't interact

with other teams enough.1 3 3 Theoretical airflow analysis must include

potential losses. Jordan

7 Stove 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. Michal

8Insufficient interaction between

SD1 Thermoelectric Stove Teams.

Stove does not meet needs or specs. Don't consult other teams. 2 2 4 Maintain consistent communication with other

teams. Rob

9 Heat output by stove is not adjustable.

Stove will resemble current stoves.

Did not take customer needs into consideration. 3 2 6 Coordinate with thermoelectric fan group to

ensure flow is adjustable. Jordan

10 Stove not properly designed for Haitian customs/ traditions.

Haitians will not adopt the new technology for use.

Insufficient knowledge of current cooking practices. 2 3 6 Pay close attention to customer needs and

engineering specs. Brian

11 Cannot be manufactured within Haitian abilities. Stove cannot be built in Haiti. The stove design is too

complex. 2 3 6 Do not overdesign the stove. Michal

12 Materials unavailable for prototype stove.

Cannot build or test a stove with the correct materials.

Materials are unavailable to us or ordered too late. 2 2 4 Do not delay in ordering the materials. Team

13 Stove design is unstable. Stove will tip over easily and be dangerous to operate.

Stove is top heavy or too narrow. 2 3 6 Design stove with a large footprint to ensure

stability. Michal

Benchmarking

• On average the fuel use was reduced 33%, CO emissions by 75%, and PM emissions by 46% in comparison to the three-stone fire.

• A light insulative material in the combustion chamber generally resulted in decreased levels of emissions.

• Use of a pot skirt can reduce fuel use and emissions by an additional 25 – 30%.

Rocket Stove

• Forced air stoves reduce fuel use by an average of 40% over traditional 3 stone fires.

• Reduces emissions by up to 90% compared to the three-stone fire.

• Accelerates lighting process

Forced Air

Concept Development

Nordica MacCarty, 2010, Energy for Sustainable Development, testing of fifty cooking stoves, ScienceDirect

Stove Comparison

Conceptual Designs

Design Elements

Conceptual Design

Vertical Combustion Stove

Fan Inlet

Skirt

Combustion Camber

Combustion Air Inlet

Gap forces channeling of hot gases

Air “pre-heats” before entering combustion chamber.

Minimal Heat loss around Pot

Project Plan

Questions?