This document summarizes a presentation on solar cooking. It discusses the benefits of solar cooking such as reducing deforestation and respiratory illnesses from smoke. It then covers the theory behind solar energy collection and the design features of box and parabolic solar cookers. Case studies from Peru and successful community initiatives in India and refugee camps are presented. The document emphasizes that solar cooking initiatives are most successful when they use locally available materials and simple, robust designs suited to the climate and needs of the area.

1. Solar Cooking
Quinton Stowell
Product Development
Manager
Nordson UV Ltd

2. Overview of sessions
1. Theory of Solar Energy/Cooking
2. Solar –v– Wood/gas
3. Design features of Solar Cookers
4. Case Study in Peru
5. Successful initiatives
6. Practical session

3. Who am I? – Nordson UV?

4. Links with Peru
Peru Children’s
Trust
Shantytown in
Peru

5. Why is Solar Cooking
Important?
2,000 million cook with wood (TFL)
20-25,000km2
of forest lost/year (UNEP)
Contaminated water = 80% illnesses
ARI (Acute Respiratory Infections)
Solar Cooking = no wood & no smoke

6. Energy from
the Sun?
Solar Constant =
1367 W/m2
Clear sunny day =
83% = 1134 W/m2
Engineers= 1kW/m2

7. Energy from
the Sun?

8. Theory behind Solar Energy
Low grade energy
Collect/retain…..
Box type cooker
Magnification…..
Parabolic cooker

9. Parabolic and Box Cookers

10. Wood/Gas – V – Solar
Wood Burners or Gas Solar Cookers
Disadvantages Advantages
Takes time to collect wood,
and is using up natural
resources.
Solar energy is free
Smoke filled rooms = ARI
(Acute Respiratory
Infections)
Smoke free cooking

11. Wood/Gas – V – Solar
Wood Burners or Gas Solar Cookers
Advantages Disadvantages
Cook any time.
Day/night/cloudy.
Only cook when it is sunny.
Gas is instantaneous and
controllable.
Box cookers take time to
heat up. Parabolic cookers
need frequent adjustment.
Cook summer and winter. Need to store cooker in
rainy season.

12. Parabolic – Design Features
Size of reflector
Reflectivity of
reflector
Accuracy of reflector
Emmisivity of
cooking vessel

13. Energy Calculations
Area = 1 m2
Power = 700 Watts
1 litre of water = 7 to 8 minutes
Temperature at focus =
420 deg C. (small black thermocouple)

14. Box Cooker – Design
Features
Greenhouse principle
Area of collection
Transmission of
glass/plastic
Emissivity of cooking
vessel
Insulation of box
WAPI (Water Pasteurisation
Indicator)

15. SUNSTOVE ® Design
Low cost enclosure
Sloped side walls, scrap Aluminium
Fibreglass insulation
Clear glass/plastic cover
80 – 100 deg C
10,000 in SA & India

17. Parabolic – v – Box Cooker
Parabolic Cooker Box Cooker
Disadvantages Advantages
Needs frequent
adjustment
Adjust once an hour.
More likely to be dazzled
by reflected light.
Much less reflected light.
Unstable Very stable

18. Parabolic – v – Box Cooker
Parabolic Cooker Box Cooker
Advantages Disadvantages
Very high temperatures. Only 80 – 100 deg C.
More like a BBQ or Grill Cooking takes much longer.
Easy to see it cooking
quickly.
Not too sure it is working!
(WAPI – 65 deg C)

19. Trip to Peru
10 teenagers
£30 of materials
Woodwork
Cardboard
Metalwork
Fun time

20. How did it go?
Workshops
Language!
New skills
Too small!
Too big!
Rainy season
Years later….

21. What makes an Initiative
Successful?
Choosing the right
design for the right
location.
Not this one for
£750 in Australia!

22. What makes it successful?
Over 4kWhr per m2
per day.
e.g. India, China, South Africa.
Robust, easy to use.
Perform well/efficient.
Local materials.
Very low cost.

23. Scheffler Design
Community Kitchen -
India

24. Refugee Camp - CooKit

25. What makes an Initiative
Successful?
Marketing & contacts with organisations
Existing charities
NGO’s – sustainable development
Government initiatives
Demonstrators – evangelists
Local entrepreneurs
Empowering the right people

26. Useful information
www.sunspot.org.uk
www.peruchildrenstrust.org.uk
www.sungravity.com
www.solarcooking.org
www.itdg.org (Practical Action)
www.sunspot.org.uk/ewb

27. Making your Solar Cooker
Split into groups
2 hours
Safety

28. Inner and outer sheets
Mark out
according to the
drawing
Cut with a pair of
sharp scissors
Fold with a block
of wood.

29. Make wooden frame and fit outer

30. Fit insulation then inner panel

31. Paint base plate and fit acrylic cover