Multi-stage desiccant cooling system for moderate climate

This paper presents a numerical study of a novel, multi-stage desiccant air conditioning system designed for moderate climates. The proposed system is based on multi-stage cooling process through the Maisotsenko Cycle (M-Cycle), regenerative heat and mass exchangers (pre-cooling and post-cooling) combined with a desiccant wheel. The performance of the system was analysed numerically with original ε-NTU models and it was compared with a typical solution based on a desiccant wheel and the Maisotsenko cycle. It was found that multi-stage system obtains lower supply airflow temperatures and higher moisture content decrease in desiccant wheel as compared to typical M-Cycle desiccant system. Moreover, this solution allows a decrease in the regeneration airflow temperature to 40 °C maintaining the same or lower supply airflow temperature in moderate climatic conditions. Using multi-stage cooling, the proposed system was able to attain a thermal COP (defined as amount of cooling capacity obtained by the unit divided by required heating capacity) of up to 4.0. Due to this performance the proposed system has high application potential in moderate climates.