Experimentation and thermo-enviro-economic analysis of solar still coupled with large-capacity heating and cooling units

Solar still is a water desalination method that works by the principle of evaporation and condensation, which has been adopted earlier as a simple and low energy consumption method. However, it suffers from low reliability and poor performance. Hence, the current study provides a developed solar still combined with a heat pump and an evacuated tube water heater to augment the thermal processes. The heat pump was attached to advance the condensation process. Besides, the heater was combined with the system to afford a storage medium and boost the evaporation process. Firstly, a parametric analysis was performed in order to select a suitable water recirculation rate and operating temperature. The productivity increased linearly with the temperature by a rate of about 0.035 L/h/m² for a 1 ℃ temperature rise until below 68 ℃; then, the relation becomes exponential where the productivity increased by 0.16 L/h/m² after a 1.5 ℃ temperature rise. Daily, the modified design exhibited productivity, energetic efficiency, and exergetic efficiency of 13.38 L/m², 44.12 %, and 4.17 %, respectively. Furthermore, including cover cooling boosted these findings to 14.22 L/m², 47.79 %, and 4.69 %, which were higher than that of a basic distiller by 291.73, 16.05, and 30.28 %, respectively. From the cost perspective, the minimum distilled water price was obtained at a 20-year lifetime span and a 5 % interest rate of 0.0121 $/L.