Writer: Vienne Lung

Having a barbecue party with our beloved friends and families is always on top of the wish-list in both hot summer days and cold winter nights. However, firing up our grills with traditional fuels such as wood chips, charcoal or propane could cause a great amount of carbon emission. Not only did such practices pollute the fresh air, but it would also accelerate climate crisis. Will there be any possible way for us to grill without causing ill to the environment? Solar-powered grills may be the answer we are searching for.

As early as 1870s, the idea of cooking meals from the sun had already been adopted by the French Army. It is worth noting that sunlight is not hot in itself; the reason that we feel warm under the sun is because of the interaction of sunlight and molecules in our skin. Hence, solar-powered grills do not cook food by the sun’s heat, but by converting the light energy from sun rays into thermal energy. The working principle is to first concentrate the sunlight onto reflective surfaces such as mirror, metal and tin, reflect the sun rays towards the blackened pots and pans with high thermal absorptance, and lastly, heat the food in the cooking apparatus through conduction. To trap and retain the heat, a transparent cover could be added on top to create a greenhouse effect.

Until now, more than 300 models of solar cooker have been developed for different cooking modes, such as panel design and box designs. Meanwhile, solar cookers are relatively inexpensive compared to traditional stoves yet similarly powerful, which some high-performance solar cookers can attain temperatures up to 290 °C. They can also be built with simple tools- for instance by covering an umbrella with aluminum foil. Use your imagination! Next time when you want to grill your foods, try to use or even build a solar-powered grill!

Reference:
Nichols, C. Alan. THE TRACKING SOLAR COOKER. Retrieved from
http://solarcooking.org/plans/Cookerbo.pdf
Solar Cooker at Cantinawest. "Solar Cookers: Varieties and Styles". Retrieved from
https://www.solarcooker-at-cantinawest.com/solarcookers-types.html

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