Comparative performance analysis of different solar desiccant dehumidification systems

The transient performance of different configurations of solar desiccant cooling systems is analyzed and compared based on the concept of Finite Time Thermodynamics. The TRNSYS software is used to conduct the transient simulation, and the results are compared with the experimental data in literature. Solar desiccant cooling systems are studied in 3 different configurations, in which fresh air, conditioned air, and a mixture of fresh air and conditioned air enter the dehumidifier wheel, respectively. Also, the performance of desiccant cooling system is investigated in single-stage and double-stage configurations to consider the effect of the number of dehumidifier wheels. The coefficient of performance (COP) and exergy efficiency of different configurations are evaluated to determine the optimum arrangement. The highest COP is achieved for Dunckle configuration in ventilation mode and for Uçkan configuration in recirculation mode. The results indicate that the COP of single-stage systems is higher than double-stage in both recirculation and ventilation modes. The highest COP and exergy efficiency are achieved for Dunckle configuration in ventilation mode as 0.6 and 35%, respectively. Implementation of heat recovery system improves the performance of double-stage configuration more than the single-stage system. An economic analysis is performed to compare different configurations based on electrical energy saving and payback period. The result indicates that the Uckan and Dunckle configurations consume 50% lower electrical energy compared to air conditioning heat pumps with payback period of about 4 years.