Solar-assisted desiccant dehumidification system to improve performance of evaporatively cooled window in hot and -humid climates

Abstract

This study examines the performance of an integrated evaporatively-cooled window (ECW) with a desiccant dehumidification system (DDS) combined with a photovoltaic/thermal (PV/t) system. The hybrid system (ECW-DDS) is applied on a glazed building surface to reduce its temperature and the associated space-cooling load. The system performance is studied during the summer months with hot and humid conditions in which the benefits of passive cooling systems are generally restricted. Mathematical models for each system component/process were integrated to predict the system effectiveness for a case study of a typical office space located in Jeddah, Kingdom of Saudi Arabia. The integrated system effectiveness was compared to two cases where the system was not installed for a clear double glass window and where only the ECW system is employed without the dehumidification of ambient air. The hybrid system (ECW-DDS) proved to reduce the inner window temperature by 5 °C, 7 °C, 4 °C, and 5 °C for June, July, August, and September, respectively resulting in an 11% decrease of the total cooling load over the summer months. In addition, the ECW-DDS system performed much better than the ECW system when humid conditions prevailed in September. For instance, the air leaving the evaporative cooler on a typical day of September recorded a temperature reduction of 14% in the case of the ECW-DDS system compared to 1% only in the case of the ECW system.