A feasibility study of a solar desiccant air-conditioning system - Part II: Transient simulation and economics

In this paper, a solid desiccant cooling system with a backup vapour compre ssion system is simulated using TRNSYS and the performance of the system is evaluated in four cities in the United States with different climates. Eco nomic analysis is performed in order to assess the feasibility of these sys tems and to determine the relevant economic parameters such as life cycle c osts, life cycle savings and payback periods. Results show that the system has higher COP values for the locations with more latent loads. The air con ditioner was able to meet the cooling demand in all four regions, but it ne eded more auxiliary energy in the Eastern and Mountain regions than in the Central region, because of the higher solar fraction in the Central region. The simulation also showed that the desiccant cooling system by itself was capable of meeting the cooling demand and hence the requirement of a backu p system may be eliminated. Thermal and economic parameters were analysed f or varying solar subsystem sizes which proved helpful in optimizing the des ign of the solar system. Recommendations to minimize the auxiliary energy c osts using different methods for supplying the thermal energy for desiccant regeneration are described. Copyright (C) 1999 John Wiley & Sons, Ltd.