Modifying a Compression Refrigeration System and Investigate the Enhancement of COP

Abstract

Abstract The Compression Refrigeration Cycles is the most conventional method used in air conditioning and refrigeration systems. It can be considered as the most effective technique due to its high thermal efficiency and capability of producing several tons of refrigeration and heating powers However, this cooling power and efficiency of the conventional vaporcompression air condition units can face a significant reduction when is operating at extremely severe (hot and dry) weather. This decrease is mainly affected by the rise of the temperature (and pressure) of the condenser of the refrigeration system as the temperature of the ambient air increases.Unfortunately, Iraq has the most extreme summer season especially in June and July when the temperature reaches or exceeds to 50 ºC. Hence, the interpretation of utilizing geothermal cooling in harshly hot climatic conditions for improving the performance of conventional vaporcompression refrigeration systems was experimentally investigated in this study.The use of ground cooling in regions with a hot environment for split system air conditioners was emphasized. To support the success and effectiveness of the geothermal cooling technique, evaporative cooling was also performed for decreasing the temperature of the refrigerant in used During the hottest three months of the year (June, July and August), experimental tests of the standardized and modified vapor compression refrigeration system (A/C - split air conditioner) were conducted in the laboratory of Mechanical Engineering, at University of Diyala in Iraq. For the modified split A/C unit, three different methods were used to assess its thermal and overall performance. All of the utilized method (first, second V and third methods) showed that a reduction in the energy consumption with a significant increase in the cooling capacity and coefficient of performance were achieved. Examination of the thermodynamic properties of the proposed system reveals increases in the performance coefficient of about 39%. Experimental results showed that the condenser temperature decreased from 115 to 105 °C during the use of ground cooling In addition, an improvement of 45% on the performance coefficient and an increase in the cooling capacity by 35%. As for the use of the geothermal heat exchanger, the condenser temperature decreased from 116 to 110 °C and the performance coefficient improved by 41% .When using evaporative cooling, the condenser temperature decreased from 110 to 88°C.In addition, 65% improvement was made to the performance coefficient of the vapor pressure refrigerator cycle, as well as a decrease in the evaporator temperature from 6 to 3.5 °C and an increase in the cooling capacity by an average of 52%