Table 2.

Recent studies on the performance of membrane distillation systems using heat storage materials

Ref	Nature	Improvement-techniques	Results
Abdelgaied et al. (2020)	Experimental	Evacuated tube solar collector + Paraffin wax as energy storage materials (Solid/liquid heat capacity 2.95/2.51 kJ/kg °C) + Evaporative cooling	• For utilizing the Paraffin wax as energy storage materials, the productivity will be improved by a rate varying between 33.11 and 43.18% compared to cases without storage materials • GOR for a solar TDCMD with EC reached 0.93. While adding the Paraffin wax increases the GOR to 1.25
Chafidz et al. (2014)	Experimental	Evacuated tube solar collector + Thermal storage tank contains hot water + heat pump driven by PV cell	15.39 L/h average productivity with feed temperature of 69 °C
Chang et al. (2012)	Theoretical	Flat plate solar collector + Thermal storage tank contains hot water	0.12 kg water productivity in 6 h
Gustafson et al. (2018)	Experimental + Theoretical	Waste heat + Chiller + Thermal storage tank contains hot water	The higher water flux occurs when the waste heat source is on because it stores a greater quantity of heat at a faster rate
Kim et al. (2021)	Theoretical	Feed preheating using flat plate and evacuated tube collectors + Thermal storage tank with phase change materials (Sodium alum (NaAl(SO4)2·12H2O) with heat capacity of 181 kJ/kg) with 28-stage vacuum membrane distillation	• Gain output ratio of 28-stage system reached 47% • System performance improved with increasing number of stage • The produced fresh water cost reached 0.97 $/m3