Designing and optimization of solar assisted ground source heat pump system to supply heating, cooling and hot water demands

摘要

This paper puts forward the simulations of different configurations of combined solar evacuated tubular collector with a ground source heat pump system to meet the heating, cooling and hot water demands of a house in Tabriz. The configurations include: indirect expansion (parallel), indirect expansion (series) and direct expansion. The simulation was done in TRNSYS with 9 m(2) evacuated tubular solar collector and three boreholes with depths of 75 m. Power consumption and COP of all configurations were compared, and the optimum configuration had the highest value of overall COP which is the indirect expansion in parallel mode with the overall COP of 3.96. Furthermore, the economic analysis was done to compare the proposed optimum system with the conventional ones, where a payback period of about 13 years was obtained. On the other hand, by considering the environmental effects of fossil fuels produced by conventional systems and natural gas exporting income, the amount of 433.8 US$ and 2629 US$ will be saved, annually. By adding the environmental and natural gas exporting costs to the operating costs of the conventional system, the payback period was reduced down to 6 years, showing that the system can be feasible in the northern parts of Iran with a cold climate.