Economic and Thermodynamic Evaluations of Using Geothermal Heat Pumps in Different Climate Zone (Case Study: Iran)

Abstract

Increasing in energy demand has led countries to find the most efficient way for supplying energy. According to many negative environmental impact of fossil fuels and of course the problem of diminishing, the idea of replacing renewables become more important among developing countries. Iran is one of the developing countries which has a high potential of renewable energies. Indeed, it has used a variety of renewables for the purpose of decreasing fossil fuels share. Geothermal energy is kind of renewables which are not widely used in Iran. It is mainly for this reason that, the feasibility and economic assessments have not truly considered in order to find best area around the country. In this study, we focused on geothermal heat pumps particularly. So, economic and thermodynamic analysis have been conducted in order to determine the best region based on three climate zone in Iran (high, low, and medium temperature). Regarding this circumstances, we analyzed 3 cities (Bushehr, Sarab, and Yazd) of these different regions and applied exergy and economic evaluations. Therefore, the second law efficiency calculated for the mentioned cities to compare the GSHP efficiency in different climates. As a result, the coldest city (Sarab) indicates the highest efficiency (around 1). Relating the economic analysis, the RETScreen software was chosen. Seemingly, it is clear cut that the cold region has the lowest payback time (3.5 years). Concequently, the cold region is the best location to implement geothermal heat pump as a replacement of fossil fuels.