Abstract In this research, a numerical model has been developed to analyze direct expansion geothermal heat pump in steady state. The current numerical solution examines the analysis of the system in different working conditions, then by using simulation, it eva‎luates the characteristics of the system such as the heat capacity and the performance coefficient of the system. Also, in order to eva‎luate the performance of the system, parametric studies on the effect of various parameters including The temperature difference of the ground with the outlet temperature of the evaporator, the speed of the compressor, the temperature and the mass flow rate of the water entering the gas cooler was done. Then it was determined that there is a maximum value of the system performance coefficient in a value of the difference between the temperature of the ground and the outlet temperature of the evaporator. Also, increasing the speed of the compressor and the temperature of the inlet water to the gas cooler is associated with a decrease in the system's performance factor, and an increase in the mass flow rate of the inlet water to the gas cooler is associated with an increase in the system's performance factor. The results of this research, including the heat capacity, the performance coefficient of the ground exchanger, can be used in the design and optimization of a direct expansion geothermal heat pump.

سعيد جاني

اميرحسين ميثمي , مرضيه رضازاده