Experimental study on the effect of coupling parabolic trough collector with double slope solar still on its performance

The performance of coupling parabolic trough collector (PTC) with double slope solar still is investigated experimentally. The incident solar energy on the PTC is transferred to the solar still by oil pipes connected with finned-piped loop heat exchanger imbedded in the solar still. The experiments are conducted at summer and winter times for three systems; conventional solar still, solar still with fixed PTC and with tracked PTC and for two cases of saline water depth in the basin 20 and 30 mm. The results illustrate that the solar still with PTC has higher sill temperature and productivity compared with conventional solar still. The freshwater productivity of solar still with tracked PTC is higher than that of fixed PTC by about 28.1% and for conventional solar still by about 142.3% at saline water depth 20 mm in summer. Freshwater productivity is about 8.53 kg/m2/ day and 4.03 kg/m2/day for solar still coupled with fixed PTC in the summer and winter respectively. The results also illustrate that the performance of solar still in winter is smaller than summer for all studied cases and systems. In summer and at saline water depth 20 mm, the daily efficiency of the conventional solar still, solar still with fixed PTC and solar still with tracked PTC are 36.87, 23.26 and 29.81% respectively.