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The simulations found that the boilers were only active during peak loads and to assist with heating domestic hot water above the heat pump set point. The solar fraction of the total load was only 20% on a yearly basis; however, it should be noted that this does not take into account the heat stored into the ground which improves the heat pump COP. On a yearly basis, the heat pump contribution was found to be approximately 40% of the total energy input. A lower limit (-3C) was set on the ground storage in order to prevent freezing. After a few years of operation, the heat pump was frequently unable to operate at full power since the ground temperature had decreased. Between the 1 and 10 year of operation, the load met by the heat pump decreased from 50% to 37%. By the 20 year of operation the total energy use by the boilers had increased from 305 to 370 MWh. | The simulations found that the boilers were only active during peak loads and to assist with heating domestic hot water above the heat pump set point. The solar fraction of the total load was only 20% on a yearly basis; however, it should be noted that this does not take into account the heat stored into the ground which improves the heat pump COP. On a yearly basis, the heat pump contribution was found to be approximately 40% of the total energy input. A lower limit (-3C) was set on the ground storage in order to prevent freezing. After a few years of operation, the heat pump was frequently unable to operate at full power since the ground temperature had decreased. Between the 1 and 10 year of operation, the load met by the heat pump decreased from 50% to 37%. By the 20 year of operation the total energy use by the boilers had increased from 305 to 370 MWh. | ||
Running the simulations with different borehole spacing found a significant impact on the ground temperature. Borehole spacing ranging between 15m and 32m resulted in an average ground temperature difference of 3C over 20 years of operation. Simulations were also carried out using flat plate collectors in place of evacuated tube collectors. The difference in average ground temperature after a year, however, was found to be below 0.1C between evacuated tubes and flat plate collectors, leading to similar solar fraction values. Overall, the study concluded that the selected design provided a | Running the simulations with different borehole spacing found a significant impact on the ground temperature. Borehole spacing ranging between 15m and 32m resulted in an average ground temperature difference of 3C over 20 years of operation. Simulations were also carried out using flat plate collectors in place of evacuated tube collectors. The difference in average ground temperature after a year, however, was found to be below 0.1C between evacuated tubes and flat plate collectors, leading to similar solar fraction values. Overall, the study concluded that the selected design provided a renewable energy fraction of 30 to 40% over the 20 years. Compared to boiler only systems with 90% efficiency, the energy savings ranged between 40 to 50% (Kummert and Bernier, 2005). | ||
Simulation studies conducted by the Energy Research Centre in the Netherlands have shown promising results for photovoltaic/thermal (PVT) panels to be used in combination with a ground-source heat pump system for residential applications. Their system utilized 25m of PVT panels. The heat produced from the PVT panels, were primarily used to for domestic hot water. Any additional heat was stored in the ground using two 35m vertical ground loops. During the winter, heat was retrieved from the ground and distributed to either the hot water system or for floor heating. Results from these simulations indicated that the system was capable of providing 100% of the total heat demand for a typical newly-built Dutch one-family home, as well as being able to supply 96% of the electricity required to run the system (Baker et al., 2004). | Simulation studies conducted by the Energy Research Centre in the Netherlands have shown promising results for photovoltaic/thermal (PVT) panels to be used in combination with a ground-source heat pump system for residential applications. Their system utilized 25m of PVT panels. The heat produced from the PVT panels, were primarily used to for domestic hot water. Any additional heat was stored in the ground using two 35m vertical ground loops. During the winter, heat was retrieved from the ground and distributed to either the hot water system or for floor heating. Results from these simulations indicated that the system was capable of providing 100% of the total heat demand for a typical newly-built Dutch one-family home, as well as being able to supply 96% of the electricity required to run the system (Baker et al., 2004). | ||