Investigation of a compact hybrid liquid-desiccant air-conditioning system for return air dehumidification

In some automatic workshops, pharmaceutical warehouses, etc., there are control requirements for indoor air temperature and humidity, yet almost no occupants or no fresh air demand in the rooms. In this study, a hybrid liquid-desiccant air-conditioning (LDAC) system is proposed for the unoccupied rooms without fresh air demand. In the proposed system, the liquid dehumidifier and regenerator are cascaded, and the regeneration process is creatively moved to indoors. Two systems are selected as the reference systems, i.e., conventional vapor compression system (reference system I) and conventional LDAC system using outdoor air for regeneration (reference system II). The simulation results reveal that, under the typical summer condition in Guangzhou of China, the coefficients of performance (COPsys) of the proposed system, reference system I, and reference system II are 2.6, 1.8, and 2.3, respectively, when the air is dehumidified from 13.0 to 7.7 g/kg. Compared to the reference system I, the reheating process can be avoided, and higher-temperature chilled water at 16 degrees C can be used in the proposed system. Compared to the reference system II, using indoor air for regeneration helps to reduce the regeneration temperature. Thus, the proposed system demonstrates energy and space advantages than the reference systems.