Numerical and experimental investigation of a novel hybrid indirect-direct evaporative cooling system with enhanced humidity regulation: A case study in hot-humid conditions

Evaporative cooling is a sustainable and cost-effective substitute to the conventional mechanical refrigeration and air conditioning systems. Its widespread application is limited in hot and humid climatic conditions, where such systems exhibit excessive addition of moisture content to supply air. This research presents a hybrid indirect direct evaporative cooling (HIDEC) system, enhanced with a forced-draft cooling tower for water temperature control and a silica-gel desiccant dehumidifier for post-cooling moisture regulation. The 3D HIDEC CFD model comprising the k-ε turbulence model, the heat transfer in fluids model, and the moisture transport interface is developed using COMSOL Multiphysics. It is experimentally validated in real-time composite climatic conditions. The hybrid configuration exhibits an enhanced moisture regulation and cooling stability compared to the conventional IEC/DEC arrangements. The numerical CFD analysis reveals system's optimal operating zones under varying humidity and temperature conditions, offering unique design insights on the high-performance hybrid evaporative cooling systems catering to hot-humid and hot-dry conditions. Parametric analysis of the experimental HIDEC system yields a maximum cooling capacity of 25.4 kW and COP of 24.2 during hot and dry conditions whereas, a maximum cooling capacity of 7.8 kW and COP of 7.1 is observed during hot and humid conditions. • Numerical and experimental analysis on novel HIDEC system integrating cooling tower and post-cooling dehumidification mechanism is presented. • HIDEC system is numerically modelled and experimentally validated during real-time hot-dry and hot-humid conditions. • 3D numerical HIDEC CFD analysis comprises k-ε turbulent flow, heat transfer in fluids and moisture transport models. • Parametric evaluation yields a maximum COP of 24.2 and cooling capacity of 25.4 kW during hot-dry conditions.