Experimental study of solar energy storage and space heating using solar assisted ground source heat pump system for Indian climatic conditions

This paper discusses the performance of a solar assisted ground source heat pump (SAGSHP) system used for storage of solar energy in day time and space heating at night. Experiments were conducted to estimate the effectiveness of solar energy storage under the ground using a U-tube ground heat exchanger by absorbing solar energy from 9 A.M. to 5 P.M. and utilize the stored energy during space heating in the night time from 7 P.M. to 3 A.M.. Using the experimental data, heat absorbed by the solar collector, heat injected into the ground, heat extracted from the ground and COP of the system have been computed. Results indicate that heat absorption by the solar collector varied from 2.07 to 2.56 kW with increase in mass flow rate. Due to heat losses, only 1.991-2.414 kW of solar heat could be injected into the ground in the day time. Increase in mass flow rate of heat transfer fluid in the collector and ground heat exchanger has resulted in 21% increase in heat injection into the ground. Due to charging of ground, thermal energy of 2.8-3.2 times the work input to the solar collector could be extracted additionally from the ground in the night time for space heating. Charging of ground has resulted in 23% increase in the COP of the system for space heating in the night time.