Study Of Optimal Control Strategies For Hybrid Ground-Source Heat Pump System In Wuhan

Ground-coupled heat pump system, use soil as energy carrier, is a central air-conditioning system for heating and cooling of using new energy sources and environmental protection. And the application of hybrid ground-source heat pump system makes this kind of central air-conditioning system became popular all over the country. However, the issue of soil heat accumulation seriously affects the efficiency of whole system, so the optimization design and control of a hybrid ground-source heat pump system is of momentous significance for energy conservation and developing the renewable energy resources.In this study, a cooling tower-ground coupled heat pump system was designed for an typical office building in Wuhan, China, and the model of this system was established by Fluent. By means of simulation in the condition of differential temperature control strategy, the issue of soil heat accumulation was proved. Therefore, two new kinds of control strategies had come up and dynamical process simulations were studied on them.The results of the simulation indicate that the primary cause of heat accumulation is the relative low soil thermal diffusivity, which makes the heat can not diffuse outward, and the optimal control strategy must base on it. One control strategy of turning on the cooling tower at night can transfer some heat from soil to outdoor in heavy heat accumulation, but cost relative high energy consumption. While the other control strategy of running in heating mode at night can decrease the soil temperature steadily, and reduce the soil heat accumulation effectively. Besides, this kind of control strategy is an effectual means in peak load shifting, especially in the condition of time-of-use (TOU) electricity price.In this paper, based on the comparison of the original differential temperature control strategy and other two new kinds of control strategies, advantages and disadvantages were described. And the conclusions have reference value to hybrid ground-source heat pump system design and optimization in Wuhan, China.