Vapour compression refrigeration with biomass operated bubble column humidification and dehumidification desalination system

Abstract

This work focuses on the performance augmentation in a vapor compression refrigeration (VCR) system integrated with biomass operated bubble column humidification–dehumidification desalination unit. The saline water supplied to the bubble column humidifier is preheated while pass-ing around the condenser of the VCR system. It is a sub-cooling process that leads to more heat rejection to surrounding and further increases the coefficient of performance (COP). The saline water and air from the blower are then heated by biomass energy in the bubble column humidifier and the air gets humidified and sent to a dehumidifier. A dehumidifier is a triple pipe heat exchanger where the refrigerant flows in the inner pipe which flows between the evaporator and compressor of the VCR. Humid air from the humidifier flows at the middle pipe and the saline water flows in the outermost pipe. As the humid air in contact with both cold refrigerant and saline water, moist air is condensed, and the pure water is collected. It is found that the distillate output and COP of the VCR unit increase with air mass flow rate, water depth and temperature in the humidifier. Theoretical results of specific humidity of air outlet from the humidifier are val-idated with experimental work within 10% deviation. The distilled water cost of 0.067 $/kg and the gained output ratio ranges between 0.286 and 0.388 for the proposed system.