Experimental and theoretical analysis of a simple solar oven in the climate of Costa Rica — I

Abstract Inexpensive and easy to fabricate solar ovens have been made with available materials. One reflector has also been mounted to increase the input radiation on the hot absorbing plate which can be adjusted manually according to the need. This has been used by the author for the last 7 years to cook almost all types of vegetables, including rice, pulses, chicken, fish and beef and to bake bread and cake etc. Experimental studies have also been made on the variation of plate temperature, solar intensity, time to cook vegetables. These are given for the various cases of adjustment of the oven, depending on the convenience for the user. Furthermore, the insulating properties of the cooker are also studied. Maximum plate temperature observed was between 130 and 150°C and one cooked meal for a family of four persons can be made in 2–3 h. Thermal efficiency and heat loss coefficient, deduced from these measurements, varies between 30–40% and 4–9 W/m2°C. Simple theoretical analyses have beend used to explain these experimental data, taking into account heat capacity of various materials. The agreement is fairly good. Finally, some practical conclusions have been drawn.