Performance analysis of a solid desiccant cooling system for a residential air conditioning system

Abstract

Desiccant cooling systems have been regarded as alternative residential air conditioning systems, owing to their potential for considerably reducing electricity power consumption. In particular, when they are combined with distributed power generations, the overall efficiency of the system can be significantly enhanced by utilizing the system exhaust heat for the adsorption of water from the solid desiccant. However, desiccant cooling systems have a limited cooling capacity and consume an extremely high amount of thermal energy. Hybrid desiccant cooling (HDC) systems can extend their cooling capacity to satisfy the cooling load on the hottest day in the summer season by combination with an electric heat pump (EHP). In this study, one-dimensional steady state models of desiccant cooling systems were developed using MATLAB-Simulink®. Three types of desiccant cooling system models, direct evaporative cooling (DEC), indirect evaporative cooling (IEC), and HDC systems, have been simulated, and their cooling performance under various temperatures ranges from 25 °C to 50 °C and various humidity conditions ranges from 4% to 98%, which represent the weather of summer seasons worldwide, have been compared. DEC system has enough cooling performance to satisfy the target cooling load only when the outdoor temperatures becomes lower than 35 °C. When the outdoor temperature becomes exceeds 40 °C, the total COP of the HDC system is significantly increased and becomes higher than that of the IEC system.