An Experimental On Subcooling Potential By Geothermal In CO2 Air Conditioning System

This study focused on assessing the geothermal subcooling potential for the air conditioning system using CO
2
that operates in the transcritical state. In this study, the relationship between the parameters such as the subcooling quantity, the cooler pressure, and the mass flow rate was determined for the best operating conditions. The cooling capacity and COP (Coefficient of Performance) are also compared under different conditions: Without geothermal subcooling, with geothermal subcooling using a bare tube, and with geothermal subcooling using a water-covered tube. The results of study showed that, using geothermal subcooling with the water-covered tube may achieve the highest COP of 5.69 while using the bare tube of 4.71 compared to 4.53 without using geothermal subcooling. When reducing the capacity of the system, the COP decreases significantly. The COP tends to decrease when increasing the subcooling quantity in both cases. The mass flow rates were also analyzed in this study. When the mass flow rate is reduced, the subcooling quantity tends to decrease. However, in the case of the geothermal subcooling by a bare tube, the subcooling quantity decreases more than that by a water-covered tube. The results showed that although geothermal subcooling is highly effective, it is important to control the cooler pressure within the allowable range for the maximum energy efficiency.