EWF Solar Oven Team Chez Helios End of the Semester Presentation May 11, 2004

The Problem Two billion people don’t have clean fuel for cooking and are forced to cook with wood or other biomass. One billion children suffer from diarrhea each year caused by contaminated drinking water. Seven thousand of them die daily.

Cooking with Biomass Gathering fuel wood takes time and energy. Deforestation makes wood hard to find. Some resort to using dirtier fuels such as crop waste and dung. Household stoves don’t completely combust biomass, emitting health-damaging pollutants into the air. In India, an estimated 500,000 women and children under 5 die annually from the effects of solid cooking fuels.

Solar Ovens Solar ovens can reduce fuel wood consumption, emission of greenhouse gasses and health problems related to burning of solid fuels. Can easily pasteurize water at 65°C for 6 minutes Cost of 20USD per oven is equivalent to 2 weeks of purchased fuel. Lower cooking temperatures, time required to cook and cultural habits limit ovens’ success Better-performing ovens may be more likely to be adopted

Objectives and Scope To gather empirical, test-standard data on Solar Box Cookers (SBCs) Features to be tested include: –Double paned glass –Type of insulation for the box –Interior oven coating –Effect of heat-retaining objects placed in oven –Reflective material used Make data available to public Not to create “The Ultimate Oven”

Presentation Outline MotivationObjectives STEVEN Foundation Related Work Specific Tasks Progress Semester summary Future Plans

STEVEN Foundation A non-profit, incorporated in 1986 A non-profit, incorporated in 1986 Focuses on sustainable, appropriate technology Focuses on sustainable, appropriate technology – Alternate energy sources – Produced and operated by local community Has done solar oven demos in: Has done solar oven demos in: – Haiti – Peru

Related Work Abundance of past research Abundance of past research – Solar Cooking Archive ( – Qualitative information – Not standardized, hard to make comparisons ASAE X580 Test Standard ASAE X580 Test Standard – Standardize results, allows fair comparisons – A single number: standardized cooking power

Project Tasks 1. Oven construction 2. Development of test method 1.Test standard compliance 2.Data collection 3. Testing of control ovens

Oven construction Blueprints based on – STEVEN Foundation’s 1996 SBC Manual – SBC provided to us by Francis Vanek Modifications to plans as written in the manual include: –Thinner plywood for outside box –90° Angle brackets added to outside box –Mitered glass cover –Recessed wood frame

Oven construction Modifications (cont.) –Slightly thicker metal liner –Only bottom of metal liner painted –8 panels rather than four –Panel frame and support scheme –Newspaper insulation More time consuming than originally expected

Test Method: X580 Compliance Based on ASAE’s X580 solar oven test standard Yields a standardized cooking power for each test Some restrictions in test standard lifted due to location in Ithaca, NY

Sample Data

Testing: Data Collection Based on a pre-existing system in the Civil Infrastructure Lab Thermocouples in several locations –Either side of insulation –Water inside pots –Either side of glass –Ambient Radiation pyranometer Weather station

Testing Control Ovens Discovered Styrofoam is a very poor choice for insulation Made modifications to testing techniques –Location of ovens –Placement of pyranometer Found that the two ovens we built performed very similarly, as desired. –First Oven- SCP = 81.1 W –Second Oven- SCP = 82.7 W

Summary of Semester Deliverables Developed construction blueprints for building a solar box cooker. Constructed two unmodified solar box cookers. Developed a set of testing procedures that meets the ASAE X580 test standards Set up a testing station capable of testing two ovens simultaneously. Work done in this semester will act as a solid foundation for future solar oven testing.

Plans for the Future Summer Plans: construct third oven find alternative reflective material Begin testing variables including: 1. Double glazing the oven door 2. Using another type of insulation 3. Painting the interior oven sides flat black 4. Placing a large thermal mass in the oven to improve heat retention 5. Using different reflective materials bridge to the fall semester Future, future plans: create database for STEVEN Foundation Make connections with interested users and install solar ovens