Geothermal Heat Pumps and Their Impact on Building Energy Efficiency and Ecology

This article analyses the impact of ground-source heat pumps on the energy efficiency and environmental impact of a residential building, depending on the temperature of the ground source, the flow temperature of the heating system, and the domestic hot water temperature. In the section on heating, the best results were obtained for the 35/28 °C system at a ground temperature of 1 °C, for which the SCOP was 4.81, the system efficiency was 3.90, the final energy was 5.6 kWh/m2yr, and the primary energy was 13.9 kWh/m2yr. The least favourable heat pump heating option was recorded for the 55/48 °C system and a ground temperature of −1 °C, with a SCOP of 3.31 and a primary energy of 17.4 kWh/m2yr. For domestic hot water, the best results were achieved at a temperature of 47 °C and a ground temperature of 1 °C, for which the SCOP reached 3.88, and the primary energy was 23.6 kWh/m2yr, whereas the least favourable variant (55 °C/−1 °C) was characterised by a SCOP of 3.31 and primary energy of 27.5 kWh/m2yr. It was demonstrated that lowering the temperature on the upper-source side improves the system’s energy performance to a greater extent than changes in ground temperature. At the same time, improvements in energy efficiency reduced pollutant emissions and lowered the equivalent emission ZrSO2 index. The results confirm that the actual energy and environmental potential of ground-source heat pumps depend primarily on their integration with low-temperature systems.