Investigation experimentally the impact of condensation rate on solar still performance at different thermal energy storages

摘要

In this paper, an experimental investigation is performed on the impact of condensation rate of solar still condenser at different thermal energy storage materials on the performance of single slope passive solar still. The condensation rate is changed by installing different designs of the still condenser: (i) glass plate condenser, GC, (ii) corrugated aluminum sheet heat sink condenser, CHS, (iii) aluminum heat sink condenser having vertical rectangular fins at its outer surfaces RHS, (iv) aluminum heat sink condenser having pin fins at its outer surface, PHS, (v) aluminum heat sink condenser having pin fins at its outer and inner surfaces, DPHS. Two different thermal energy storage materials inside the still basin are used; sand and black wool fibers (BWF) plus pure saline water which yield different evaporation rates of the saline water. The findings show that increasing the heat transfer rate (HTR) by the condenser increases the still yield to a limit and then decreases this yield at higher rates. Moreover, increasing the evaporation rate by using thermal energy storage material reduces the negative impact of high condensation rate. The still yield of GC is the minimum while the still yield in case of PHS has the maximum production. Solar still with PHS condenser achieves maximum yield increments of 54%, 63%, 76% in case of saline water only, sand, and BWF medium in the basin, respectively compared to the case of GC condenser with saline water only (conventional still) in the basin. The conventional still has the minimum efficiency of 23.3% and the still with PHS condenser and BWF achieves the maximum still efficiencies of 40.7%. Moreover, enhancement of HTR through using of DPHS condenser reduces the still efficiency to 29.2%, 34.3%, and 37.5% in case of pure saline water, sand, and BWF, respectively. Using PHS condenser with BWF in the still basin reduces the freshwater yield cost by about 21% compared to conventional still.