EXPERIMENTAL AND THEORETICAL INVESTIGATION OF A BOX-TYPE SOLAR COOKERWITH MULTISTEP INNER REFLECTORS

We have designed and constructed a box-type solar cooker with multi-st ep inner reflectors. The inner reflectors were arranged in a three-ste p fashion to create different angles with respect to the horizontal. A transient mathematical model is presented for the cooker. It is based on an analytical solution of the energy-balance equations for differe nt components of the cooker. The cooker was tested in the laboratory w ith a solar simulator under different solar insolation. To validate th e present model, numerical calculations have been carried out using th e same conditions of indoor tests. The transient performance of the co oker was studied by computer simulation for typical summer (15 July) a nd winter (15 December) days in Tanta, latitude 30 degrees 47' N, Egyp t. Good agreement between experimental and theoretical results is obse rved. It is evident that the cooker is able to boil 1 kg of water in 2 4 min when its aperture area equals 1 m(2). The cooker can be used thr ee times a day in summer and twice a day in winter for cooking consecu tively with an overall utilization efficiency of about 30%.