Thermal performance analysis of a solar still with different absorber plates and external copper condenser

Abstract

Solar distillation is one of the cheapest and lowest energy consuming desalination processes to produce potable drinking water. The main obstacle of desalination process is the low production rate of fresh water owing to slow evaporation and condensation rate of the system. In this experiment, a double slope solar still (SS) is modified by using two different modified absorber plates and an external copper condenser (ECC). Absorber plates are modified by employing triangular and rectangular channels as they increase surface area of the absorber plates to increase heat transfer to the basin water and hence increase evaporation rate of water. ECC is designed in such a way that provides extended cool surface area in addition with glass surface to increase condensation rate. Experiments are done in the month of October for 7 days and comparative analysis is done to determine the best modification out of the 5 modifications (conventional SS, SS with triangular channeled (TC) with and without ECC and SS with rectangular channeled (RC) with and without ECC) in terms of productivity and efficiency. The maximum average productivity obtained among all the modifications is 1.7 ± 0.1 L/m2 while experimenting with SS with TC absorber plates and ECC. The maximum average overall efficiency and maximum average instantaneous efficiency both are obtained with SS with TC and ECC which are 17.86 ± 0.6% and 18.2 ± 1.6% respectively. Addition of ECC increased the average productivity by 0.66 L/m2 and overall efficiency by 7.52% than conventional SS. The economic analysis of the SSs is also conducted, and results represent that the modified SSs are approximately 55.57% cost effective than the conventional SS.