Thermal Performance and Energy Consumption of Air Conditioning Systems with Heat Exchangers for Water Heater Efficiency Improvement

Abstract

This study aims to evaluate the impact of refrigerant heat removal via a double-pipe heat exchanger on the energy consumption of air conditioning systems. Experimental parametric studies were conducted, focusing on variations in water mass flow rate and inlet water temperature. The results demonstrate that incorporating heat exchangers not only enhances the thermal efficiency of water heaters but also lowers the refrigerant temperature before it enters the condenser. As a result, the COP of the systems showed a significant improvement, depending on the water mass flow rate. An increase in the water mass flow rate through the heat exchanger led to a higher heat transfer rate, rising from 0.7 kW to 1.58 kW. This corresponded to an approximate increase in COP from 22 % to 44 %, along with a decrease in power consumption. However, to maintain stable thermal performance, the temperature of the water entering the heat exchanger should be controlled. These findings offer valuable insights for future research on heat recovery applications, particularly in air conditioners, which are increasingly in demand for residential use due to their essential role in maintaining indoor comfort.