Research on the aquifer temperature field of Groundwater Heat Pump with Pumping & Recharging in the Same Well

Mathematical model of pumping and recharging well (PRW) for ground water heat pump(GWHP) was developed and two operating modes(one is operating only in winter and the other is continuous operating in winter and intermittent operating in summer) of the PRW in Shenyang for a office building was simulated and studied using the developed model. Simulation results showed that, when the GWHP operated only in winter, the largest temperature drop was about 8.3°C at the end of the first heating season. The temperature recovered only 1.2°C in the transition season when the heat pump stopped running and the groundwater will freeze in 2~3 yeas if the system continuously running in operating only in winter mode. When the GWHP system runs in continuous operating in winter and intermittent operating in summer mode, the aquifer composed of temperature drop zone and the temperature raise zone, and the largest temperature drop and raise was about 4.5°C and 3.6°C respectively at the end of first running year. With the running of the ground water heat pump, the temperature drop zone enlarged gradually, while the temperature raise zone gradually shrunk. At the end of the fifth heating season, the temperature raise zone disappeared, the temperature drop of the aquifer was 7.5°C and the influence radius of PRW was about 58 m. It can be concluded that when the ground water heat pump operates in severe cold region, where the building heating and cold load was highly unbalanced, it was necessary to take varied seasonal thermal energy storage measures.