A performance study of the box-type solar cooker was made with special emph
asis on the shape of lid of the utensils used in a solar cooker. The study
revealed that the performance of a solar cooker can be improved if a utensi
l with a concave shape lid is used instead of a plain lid, generally provid
ed with the solar cooker. The stagnation temperature for a utensil having a
concave lid was about 2-7% more than the utensil with a normal lid. The ti
me required for heating the water up to the same temperature in both the ut
ensils was reduced by about 1-13% when a concave shape lid was used. (C) 19
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