Geothermal heat pumps are an efficient alternative to fossil fired heaters and compression chillers to heat and cool buildings. They are able to reduce both the energy demand and polluting emissions. To evaluate the efficiency of these systems, an application was studied in a residential building, divided in two independent apartments. The numerical results were produced by using the software tool TRNSYS 16. The results include the trends of the thermo-climatic variables, and to the operational mode of the heat pump. The economical aspects are very important in this kind of applications too, and a comparison between conventional and geothermal systems was shown analysing operation and capital costs. The geothermal heat pump studied in this paper produces a thermal power output of 29 kW in winter and a refrigerating power output of 26,1 KW during summer time. These data refer to nominal conditions. The ground heat exchanger system is composed by 9 boreholes with a depth of 80 m. The overall length of all boreholes is 720 m. The nine wells are organised in three series. Each series consists of three wells. The numerical simulations have highlighted that with such a system, the geothermal heat pump has a winter efficiency which rise up 4.9, and an efficiency, during the warm season, which reaches 2.3. The gap between winter and summer efficiency is due to the optimization of the system in order to satisfy the heat demand. The simulations show that the thermo-climatic variables inside the building confirm comfort conditions. In the winter the average air temperature is about 22 °C and 26 °C during the warm season. This performance produces a significant reduction of operating costs. Comparing the operating costs of this system with a conventional system with natural gas combustion, it is possible to have a reduction of 50%. In figures, the amount of this reduction, refers to this case study, is about 2,000 euros/year. A similar trend of the operating costs, can be obtained during the summer time too, when cooling is necessary.
Feasibility Study and Numerical Simulation of a Geothermal Heat Pump Plant Applied to a Residential Building
DESIDERI, UMBERTO;
2008-01-01
Abstract
Geothermal heat pumps are an efficient alternative to fossil fired heaters and compression chillers to heat and cool buildings. They are able to reduce both the energy demand and polluting emissions. To evaluate the efficiency of these systems, an application was studied in a residential building, divided in two independent apartments. The numerical results were produced by using the software tool TRNSYS 16. The results include the trends of the thermo-climatic variables, and to the operational mode of the heat pump. The economical aspects are very important in this kind of applications too, and a comparison between conventional and geothermal systems was shown analysing operation and capital costs. The geothermal heat pump studied in this paper produces a thermal power output of 29 kW in winter and a refrigerating power output of 26,1 KW during summer time. These data refer to nominal conditions. The ground heat exchanger system is composed by 9 boreholes with a depth of 80 m. The overall length of all boreholes is 720 m. The nine wells are organised in three series. Each series consists of three wells. The numerical simulations have highlighted that with such a system, the geothermal heat pump has a winter efficiency which rise up 4.9, and an efficiency, during the warm season, which reaches 2.3. The gap between winter and summer efficiency is due to the optimization of the system in order to satisfy the heat demand. The simulations show that the thermo-climatic variables inside the building confirm comfort conditions. In the winter the average air temperature is about 22 °C and 26 °C during the warm season. This performance produces a significant reduction of operating costs. Comparing the operating costs of this system with a conventional system with natural gas combustion, it is possible to have a reduction of 50%. In figures, the amount of this reduction, refers to this case study, is about 2,000 euros/year. A similar trend of the operating costs, can be obtained during the summer time too, when cooling is necessary.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
