cook stove for haiti enhancements system level design review friday, january 14 th 2011 11:00 am –...
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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?