Techno-economic analysis of different refrigerants during transient state operation in a ground source heat pump

The objective of this study isto compare different refrigerants in terms of economics andsystem performance. For this purpose, a numerical model hasbeen developed for the simulation of a ground source heat pump in heating mode. A residential building with several thermal zones in het city of Tehran is selected for this case study. In order to reduce energy consumption and meet the ilding sbu heat requirement at any time, the compressor considered with variablespeed drive. In this study, the investigated refrigerants are R410a, R407c, and R134a. Also orf all three types of refrigerants, the properties of heat exchangers are considered the same condition.In order to compare different economic parameters, theLCC is considered twenty years period. The obtained results showthat the most effective type ofrefrigerant is R134a in the considered conditions and also the average annual of COP for R134a, R410a and R407c are 3.7, 3.3 and 3 respectively. The economic results show that the use of R134a in the mentioned system can reduce the LCC with the amount of 1.16% instead of the use of R410a and 1.91% instead of the use of R407c.