Experimental investigation on improving the efficiency and water conservation performance of a novel spray-media pad coupled evaporative cooling system

• A novel spray-media pad coupled three-stage evaporative cooling system is proposed. • A test rig and performance indexes are set up to evaluate the performance of the novel cooling system. • A sensitivity analysis is also performed to assess the influence of different parameters on the performance of the novel cooling system. Evaporative cooling technology holds great potential for improving the efficiency of air-cooled chiller systems, leading to substantial energy savings. Spray cooling and media pad cooling technologies are limited by low cooling efficiency and high water consumption, respectively. A three-stage evaporative cooling system (SMEC) integrated micro-mist spray and media pad was designed to tackle these challenges. Cooling performance on SMEC, especially water conservation performance was focused. The cooling efficiency of 67.9 % is achieved by the SMEC system under standard summer air conditions of 35 °C and 60 % relative humidity. Compared to single spray and single media pad cooling systems, the SMEC system shows a 7.4 % and 10.9 % improvement in cooling efficiency, respectively, while reducing water consumption by 16.7 % and 78.5 %, respectively. The parametric sensitivity analysis showed that as the inlet air relative humidity and velocity increase, the SMEC system’s cooling and humidification performance weakens; conversely, it improves when the spray flow rate increases. Water utilization decreases with higher inlet air relative humidity and spray flow rate but increases with higher air velocity. Additionally, in the context of the SMEC system, when the media pad thickness is increased from 50 mm to 100 mm, the cooling efficiency and water evaporation efficiency are increased by 20.3 % and 3.1 %, respectively.