Energy and Exergy Analysis of Hybrid Desiccant Air Conditioning System using Molecular Sieve

Abstract

A hybrid desiccant air conditioning system combines a rotary solid desiccant dehumidifier with a vapor compression refrigeration cycle to effectively address both latent and sensible cooling demands. In this study, a comprehensive energy and exergy analysis of a hybrid desiccant air conditioning system using molecular sieve desiccant was carried out. The system consisted of a rotary solid desiccant dehumidifier integrated with a vapor compression refrigeration system and a coupled regeneration strategy using condenser waste heat and auxiliary electric heating. The experiments were conducted at fixed mass flow rates of process and regeneration air of 0.107 kg/s and 0.054 kg/s, respectively, with a constant desiccant wheel speed of 65 RPH. The system performance was evaluated in terms of coefficient of performance (COP), dehumidification effectiveness, exergy destruction, and exergy efficiency under varying process air inlet temperature (29–37°C) and humidity ratio (0.0165–0.0182 kg/kg). The results showed that the COP decreased with increasing inlet air temperature but increased with increasing humidity ratio, while dehumidification effectiveness followed a similar trend. Exergy analysis revealed that the desiccant wheel and regeneration heater were the major sources of thermodynamic irreversibility in the system. The overall system exergy efficiency reached a maximum value of approximately 21.5%. The results demonstrate the potential of hybrid desiccant cooling systems for energy-efficient air conditioning applications in hot and humid climates.

Keywords

• Hybrid desiccant air conditioning system
• molecular sieve
• energy
• exergy destruction and exergy efficiency

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