Experimental study on the operating characteristic of the desiccant cooling systems with the potential of condensing heat recovery

Abstract

The requirement for extra regeneration heat is a significant issue limiting the energy efficiency of desiccant cooling systems. To avoid the additional energy consumption, this study analyses two systems that use condensing heat to regenerate the desiccant. The experiments for the heat pump-assisted type are executed at different indoor load profiles. A comparative experiment is carried out on a water loop-assisted type. Experimental results show that the heat pump-assisted type obtains a maximum regeneration temperature of 40.4 °C and a minimum supply air humidity ratio of 3.5 g/kg DA at the outdoor temperature below 26 °C. However, the thermal imbalance problem leads to uncontrollable indoor temperatures under 50 W/m2 load conditions. The proposed operation mode automatic switching control can improve indoor temperature by switching the system between dehumidification and cooling modes. Compared to the heat pump-assisted type, the water loop-assisted type has the same dehumidification capacity and a more stable indoor thermal environment control using high temperature chilled water above 14 °C and reduce the total primary cooling energy consumption by 58%. This study analyses the feasibility of recovering condensing heat from the perspective of thermal energy analysis, and expands the research on desiccant cooling systems without extra regeneration heat sources.