Theoretical and Experimental Comparison of Box Solar Cookers with and without Internal Reflector
Kahsay, Mulu Bayray; Paintin, John; Mustefa, Anwar; Haileselassie, Asfafaw; Tesfay, Meseret; Gebray, Biniam
Original version
Energy Procedia 57 ( 2014 ) 1613 – 1622, 2013 ISES Solar World Congress 10.1016/j.egypro.2014.10.153Abstract
Box solar cookers are commonly built with internal shee
t metal painted black as an absorber. In order to
increase the performance, a design which incorporates
internal reflection is proposed in this paper. The
aim of this paper is to report
comparisons made between box solar
cookers with and without internal
reflector. Theoretical modelling of the two types of co
okers has been made by considering the radiation,
convection and conduction heat transfer employing th
e thermal network method. The theoretical analysis
made was based on steady state heat transfer analysis
of the cookers. Experimental comparisons were also
made on two cookers having the same aperture area an
d made from the same type of materials except the
internal absorber. The tests were made as per the
American Society of Agricultural Engineers (ASAE)
procedure.
The result of the theoretical analysis predicts that the performance will be higher in the cooker with
internal reflector than the same cooker without reflector. The steady state analysis shows that for the
cooker with reflection the temperature of the bottom absorber plate is higher than the cooker without
reflector. Similarly, results of dry test and water boiling test show better performance by the cooker with
reflector. The standard stagnation temperature and the
cooking power were higher in the cooker with
reflector as compared to the cooker without reflector.
In conclusion, the performance of box solar cookers
can be enhanced by making appropriate angle side w
alls of the absorber and providing internal reflection.