Thermo-economic assessment of air conditioner utilizing direct evaporative cooling: A comprehensive analysis

As concerns regarding energy consumption and environmental impact continue to grow, the need for efficient and sustainable cooling technologies becomes increasingly significant. Among various alternatives, direct evaporative cooling (DEC) has emerged as a promising solution due to its energy-efficient operation and low environmental footprint. This paper aims to provide a comprehensive thermo-economic assessment of a 5.25 kW capacity split air conditioner (SAC) integrated with direct evaporative cooling, focusing on evaluating its performance, energy consumption, coefficient of performance(COP), and economic viability. A numerical model is developed to determine the reduction in the condenser inlet air temperature due to direct evaporative cooling. The ambient temperature (30-45 degrees C), relative humidity (20-80 %), and evaporator temperature (3-12 degrees C) are taken as the design variables. Box-Behnken design (BBD) technique of response surface methodology is applied for multi-objective optimization. The COP, total cost rate (TCR), and total exergy destruction (E-D,E-t) are set as the objective functions. Cooling capacity, life period, operation time, interest rate, maintenance factor, and electricity cost are taken as constants. The thermoeconomic optimization evolved maximized COP enhancement of 68.94 %, and reduction in TCR and E-D,E-t by 26.12 % and 57.23 %, respectively. The water consumption to energy saving ratio varies from 5.5 to 9.8 L/kWh for different months of the cooling season. The thermoeconomic performance and sustainability of DECSAC is observed to significantly improve compared to conventional SAC specifically in hot-dry climates. The simple payback of the proposed system ranges between 1.21 to 2.99 years depending upon the operating conditions.