Performance analysis of a fresh air dehumidification system using heat pump with desiccant coated heat exchanger

With the increasing attention on indoor air quality, the use of fresh air conditioning systems has become more widespread in recent years. However, the dew point dehumidification method of conventional air conditioning systems results in high energy consumption because the temperature of the air needs to be reduced below the dew point temperature. The aim of this study is to evaluate the performance of a fresh air dehumidification system using a heat pump with desiccant-coated heat exchanger for of moisture removal and coefficient of performance (COP) in typical hot-humid outdoor conditions in Shanghai. The key equipment of the system is desiccant coated heat exchanger (DCHE), which is fabricated by a conventional fin-tube heat exchanger with desiccant materials coated on the fin surface. Cold capacity provided by a heat pump is used during the dehumidification process so that the harmful effect of adsorption heat could be overcome and the efficiency of dehumidification could be improved due to the DCHE. The waste heat caused by the heat pump is used to regenerate the desiccant material. The experiment results show that the average moisture removal of the system is 4.67 g/kgDA and the COP is 5.20. Higher moisture removal could be achieved in the optimised system at a lower air flow rate with a slight reduction on COP. The COP of the dehumidification system is higher than conventional air-conditioner due to the dehumidification of the desiccant.