Investigation by Yadav [2] showed that the hybrid vapor compression system was more promising under high latent heat load or higher ambient humidity conditions, and significant energy saving can be achieved over traditional compression system. Yadav and Kaushik [3] have studied a hybrid solid desiccant system. It was found that the system resulted in 25% energy saving over a VC unit. Howell and Peterson [4] reported a hybrid liquid desiccant system that can reduce the areas of evaporator and condenser by about 34%, and economize electricity consumption by about 25%. Due to high latent load ratios in supermarket, the use of vapor compression cycles is inefficient. Ref. [5] revealed a hybrid desiccant cooling system applied in supermarket could reduce energy costs about 70%. The required installed capacity of the vapor compression unit is decreased 80% with the use of hybrid systems. Ghaddar [6] reported a hybrid desiccant cooling system applied in a restaurant of Beirut. Because the restaurant adopted the hybrid desiccant cooling system, the size of the vapor compression unit is reduced from 40 kW to 28 kW when supplemented by a desiccant system. Mazzei [7] reviewed the moisture control in building. It was found that compared to the traditional vapor compression system, the use of hybrid desiccant systems cannot only control the ambient humidity but also reduce operating costs and power electric demand. However the disadvantage was the higher investments. Research on the hybrid desiccant air-conditioning is also reported in Refs. [8], [9], [10], [11] and [12]. Although the desiccant air-conditioning is so promising, the detailed theoretic analysis and experimental results pertaining to the hybrid desiccant air-conditioning are few, and especially so when it comes to the studies on the operating conditions of evaporator assisted with solid desiccant dehumidifier.
In this paper, some experiment results on a hybrid desiccant air conditioning system are reported and the effects of the relevant operating parameters on the performance of the whole system and the evaporator are analyzed.