Solar Cooking

Solar Cooking Quinton Stowell Product Development Manager Nordson UV Ltd

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

Who am I? – Nordson UV?

Links with Peru Peru Children’s Trust Shantytown in Peru

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

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

Energy from the Sun?

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

Parabolic and Box Cookers

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

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 Box cookers take time to controllable. heat up. Parabolic cookers need frequent adjustment. Cook summer and winter.

Need to store cooker in rainy season.

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

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)

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

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

Parabolic – v – Box Cooker Parabolic Cooker

Box Cooker

Disadvantages

Advantages

Needs frequent adjustment

Adjust once an hour.

More likely to be dazzledMuch less reflected light. by reflected light. Unstable

Very stable

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 longer. Easy to see it cooking quickly.

takes

much

Not too sure it is working! (WAPI – 65 deg C)

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

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

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

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.

Scheffler Design Community Kitchen - India

Refugee Camp - CooKit

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

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

Making your Solar Cooker Split into groups 2 hours Safety

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

Make wooden frame and fit outer

Fit insulation then inner panel

Paint base plate and fit acrylic cover