EPA Solar Oven Project #05301

Preliminary Design Review

February 18, 2005

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Team Solar Oven

Team Lead: Emma Fulton ISE

Team Members: Josh Bates ME

Otman El Allam ISE

Natasha Privorotskaya ME

Jon Steiner ME

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Agenda Introduction Needs Assessment Specifications/Requirements Feasibility Assessment Materials Selection Concept Development & Designs Testing Methodology Future Work Questions

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Why Solar Ovens? Average Latin American Country

35% of the population is below the poverty line and lives in rural areas

Majority cook with firewood Limited use of solar ovens

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Project Mission Statement Design, test, and build a low-cost solar

oven for use in Latin American countries using locally available resources, mass production methods, and labor

Note: Objective is not to reinvent the wheel, rather to make it suitable for use in rural Latin America

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Needs Assessment Scope Limitations Order Qualifiers Order Winners

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Scope Limitations Design should only incorporate locally available

resources, production methods, and labor Design should be mass-producible Design must be durable Design must be able to cook food and pasteurize

water Must perform user testing to ensure ease of use

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Scope Limitations (Cont’d) Design must be benchmarked against three

commercially available units Thermal analysis must be conducted on

prototypes With Graduate student assistance

Economic, social, environmental impact Lifecycle and durability analysis

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Order Qualifiers Inexpensive method Locally produced (labor and production methods) Decrease need for firewood

Decrease the rate of deforestation Decrease CO2 emissions Minimize the exposure to smoky conditions

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Pairwise Comparison of Attributes

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Ranking of Attributes

Order of Weights

ATTRIBUTE WeightImportance

(10=high, 1=low)

1 Low cost 0.167 102 Reaches Temperature Quickly 0.136 93 Reaches temperature necessary to cook food and pasteurize water 0.129 84 Easy to use 0.121 85 Durable 0.106 76 Capable of cooking large meals 0.098 67 Retains heat 0.076 68 Easy to clean 0.053 59 High packing density (stackable) 0.038 410 Light weight 0.038 411 Easy to Store/ Portable 0.030 312 Made of eco-friendly materials 0.008 1

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Order Winners: Top 5 Attributes Inexpensive design Heats up quickly Reaches temperatures necessary to cook

food and pasteurize water Easy to use Durable

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House of Quality

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Feasibility Assessment:How Many Prototypes to Build

# of Units T1 T2 E1 S1 S2 S3 S4 R1 R2 SUMBuild 1 Unit 0 0 3 3 1 3 3 3 3 19Build 2 Units 1 1 3 3 1 3 3 2 3 20Build 3 Units 2 2 3 3 2 3 3 1 3 22Build 4 Units 3 3 2 2 3 3 2 0 2 20

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Feasibility Assessment:How Many Prototypes to Build

0

1

2

3T1

T2

E1

S1

S2S3

S4

R1

R2

Build 1 Unit

Build 2 Units

Build 3 Units

Build 4 Units

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Materials Selection* Main Construction Material Reflector Material Cover Material

* CES Selector 4.5

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Main Construction Material

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Main Construction Material

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Wood Selection

Type of Wood

Price (USD/lb)

Density (lb/in3)

Thermal Expansion (µstrain/ºF)

Particle Board 0.291 0.0217 6.945

MDF 0.374 0.0271 6.945

Plywood 0.624 0.0271 3.889

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Reflector Material

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Reflector Material

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Cover Material

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Materials Chosen Main Construction Material

Particleboard Reflector

Aluminum sheet (reused) Cover

Acrylic

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Three Main Types of Solar Ovens

Box* Panel**

*http://www.exoticblades.com/tamara/sol_cook/types.html

**http://www.solarcooking.org/plans.htm

Parabolic*

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Advantages/Disadvantages

Types Advantages DisadvantagesMost commonEasy to useEasy to buildRetains heat longerEasy to build Not sturdy during windy weatherCheapest to build Easy to damageHeats up very quickly Requires direct sunlightSturdy Dangerous to use

Inconvenient (frequent adjustment)

Longer to heat up food

Parabolic

Panel

Box

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Concept Development

Homemade ~$10

Commercial: $220

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Concept Screening Process Generated concepts

Six box types Three features to add to any design One stand to hold cooker One pyramid cooker

Structured Voting Technique with team members and project sponsor

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Results of Voting

Designs Explanation # of VotesBox 1 0Box 2 0Box 3 1Box 4 Tilted top with 4 reflectors 3Box 5 Flat top, 4 reflectors 1Box 6 Flat top, 1 reflector 6Pyramid Large % metal 3

Basically the same box type

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Four Reflector Box Rear access door Proven design Good insulation Large reflectance area

Total Material Cost: $33.64

Box Type

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Single Reflector Box Good insulation Light weight Portable Inexpensive Retains heat (lid)

Total Material Cost: $15.38 Box Type

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Pyramid Reflector Box Simple to build Light weight Portable Large reflectance area

Total Material Cost: $19.65 Panel/Box Type

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Testing Methodology Determine angle of reflectors

Square 1 software Laser Testing

Mimic sun’s energy Create indoor setup Array of 9 projection lamps (300 Watts each) Calibrated solar cell Thermocouples

Test prototypes outside Thermocouples

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Picture of Indoor Testing Stand

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Future Work Calibrate testing equipment Conduct tests and analyze data Use HOQ to determine winning prototype Combine features and optimize materials Possibly build new prototype Field test in Venezuela Utilize field test results, possibly redesign

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Thanks and Questions Thanks to:

Dr. Carrano Dr. Thorn Dr. Raffaelle Carlos Plaz Mr. Wellin Dr. Mozrall Chris Wood

Questions?