Enhanced Ground Source Heat Pump System With Thermal Storage System

The short-cycling operation of a heat pump decreases energy consumption efficiency. Short-cycling operations of ground source heat pump system (GSHP) occur when the ON/OFF control of a heat pump is used in a partial load condition. It is considered effective that GSHP with capacity controls installs to suppress short-cycling operations. However, there is no report on any continuous operations by capacity control GSHP in actual operations. We confirmed that GSHP (water to water) with capacity control operates short-cycling in the residence. Short-cycling operations occurred with a sudden load fluctuation due to opening or closing of the valves. We conducted effective verification experiments of the thermal storage device at the artificial heat load fluctuations condition. When the thermal storage device installed upstream brine circulation line of the heat pump with the capacity control, continuous operations are performed. It was under the condition at the heating heat load of 5 kW is turned ON/OFF every 20 min. In this case, energy consumption efficiency of a heat pump is 13% higher than the efficiency without the thermal storage device.