Energy recovery from a vapour compression refrigeration system using humidification dehumidification desalination

Energy consumption of a process can be reduced by properly utilizing the large amount of waste heat liberated into atmosphere. The aim of this research is to improve the coefficient of performance (COP) of a vapour compression refrigeration system, by recovering waste heat from the condenser and the evaporator using humidification dehumidification desalination process. To recover the heat, air from the blower is passed through a humidifier chamber in which water is sprayed over the gunny bag placed in the air passage. The humid air circulated around the condenser coil which sub-cools the refrigerant and it also absorbs the heat from the condenser, producing hot humid air. The hot humid air is then passed over another heat exchanger (dehumidifier coil) which heats the refrigerant coming out from the evaporator so the quality of the vapour improves. At the same time, condensation occurs in the hot humid air along the surface of evaporator coil and the distilled water is collected. Refrigerator system is tested with insert like twisted tape and cone type turbulators in the dehumidifier passage to augment the performance. These modifications improved the COP of the refrigeration system up to 7.6 with a distillate water output of 0.4 l/m2 h.