Solar Energy, Vol.204, 79-89, 2020
Impact of condenser heat transfer on energy and exergy performance of active single slope solar still under hot climate conditions
This study experimentally investigates the performance of solar still coupled with a parabolic trough solar collector (PTSC) at different cooling rates based on energy, exergy, exergoeconomic, and enviroeconomic standpoints. Different solar still systems are considered; conventional solar still (CSS), solar still with heat sink condenser (MSS) and coupled with PTSC (MSS + PTSC), MSS having an umbrella and coupled with PTSC (MSS + PTSC + U), MSS with PTSC and condenser forced air cooling (MSS + PTSC + FA), and MSS + PTSC with condenser forced water cooling (MSS + PTSC + FW). Experiments are conducted under hot climate conditions of Sohag city, Egypt. Results indicated that the freshwater yield of all studied systems in ascending order is as follow; CSS + PTSC, MSS+ PTSC+ U, MSS+ PTSC, MSS+ PTSC+ FA, and MSS+ PTSC+ FW in summer with value of 7.74, 8.02, 8.68, 9.11, and 9.45 kg/m(2), respectively. The maximum exergy efficiency of 1.34% in summer is achieved in case of MSS + PTSC + FW system. The economic analysis shows that distilled water cost is minimum for MSS + PTSC + FW (similar to 0.02 $/L), while it is maximum for MSS + PTSC + U (similar to 0.022 $/L). It can be concluded that high freshwater production and less distilled water cost are making the enhanced solar desalination system feasible and competitive. Minimum exergy efficiency occurs in case of CSS+ PTC with a value of 1.197% and MSS has higher average daily exergy efficiency. MSS + PTSC achieves the best performance-based exergoeconomic approach. MSS + PTSC + FW is by far the best system in cutting down CO2 emissions.
Keywords:Solar still;Parabolic trough solar collector;Energy and exergy;Exergoeconomic;Environmental