Improving the Efficiency of a Conventional Vapor-Compression Refrigeration System used for Geothermal and Evaporative Cooling Techniques: Case Study in Iraq

Abstract

A conventional vapor compression refrigeration cycle is among the most effective technology in refrigeration systems. In the present experimental study, thermal performance and the effect of the condenser temperature have been analyzed. With the decrease in the condenser temperature, the overall performance of the refrigeration cycle is increased. However, the cooling power and efficiency of conventional vapor pressure air conditioning units can experience a significant reduction when operating in extreme weather (hot and dry). This drop is mainly affected by the increase in the temperature (and pressure) of the condenser with an increase in the ambient air temperature. Unfortunately, Iraq experiences the most extreme summer seasons especially in the months of June and July when the temperature reaches or exceeds 50° C. So, ground cooling has been used in areas with a hot environment for split system air conditioners. Evaporative cooling was also performed to lower the coolant temperature of the AC unit used inside the condenser area. Experimental results showed that when using a geothermal heat exchanger, the temperature of the condenser is reduced from 116 to 110 ° C and the coefficient of performance (COP) is improved by 41%. In addition to this when the system uses evaporative cooling the temperature of the condenser is reduced from 110 ° C to 88° C. Moreover, a 65% improvement was made in the COP of the conventional vapor compression refrigeration cycle. Furthermore, with a decrease in the evaporator temperature from 6 to 3.5 °C there was an increase in refrigeration capacity by an average of 52%.