Experimental investigation on a cooling cum desalination system using a modified mechanical heat pump

Abstract

An experimental study on a mechanical heat pump unit incorporated with a humidification-dehumidification system for desalination and cooling is presented. The experimental prototype is developed by modifying the condenser of a mechanical heat pump unit into an evaporative condenser. The evaporative condenser is used as a humidifier, and the evaporator as a dehumidifier, of the humidification-dehumidification desalination system. The proposed unit is evaluated with combinations of air and saline water flow rates, and also evaluated by means of total desalination output, cooling output, gained output ratio and energy utilization factor. At fixed air flow rate, increasing saline water flow rate decreases the desalination output, and increases the cooling output, gained output ratio and energy utilization factor, respectively. The highest fresh water yield and gained output ratio are 2.94 LPH and 1.30 respectively. The highest cooling output and energy utilization factor are 4.39 kWth and 4.12, respectively. The total urban heat island mitigation at the operating condition of 200 m3.h−1 and 380 LPH is 5.25 kWth. Compared with similar vapor compression refrigeration operated humidification dehumidification desalination units, the present study produces more fresh water yield and cooling output with fewer energy consuming devices and heat exchangers.