Surface Water Source Heat Pump System Thermal Performance Simulation And Energy-saving Operation Research

The surface water source heat pump is an environmentally-friendly and energy-saving technology, which utilizes solar energy stored in the surface water as thermal source for cooling and heating requirement. Currently, the energy-saving operation research of the heat pump system has become a very hot topic. Based on the surface water source heat pump system modeling and simulation, analysis of its appropriate operation strategy in this paper provide technical support for the actual project.Surface water temperature model is presented in this paper, and analytic solution is obtained. The results show that water source heat pump has obvious advantage in enery-saving compared with the air source heat pump and is more efficient than the cooling tower system in the general case. Based on the energy equations,the mathematical models of surface water source heat pump system component are built including evaporator model,condenser model,throttle model,compressor model, refrigerant model,fluid transportation pipeline model,variable frequency pump model.Model parameters are identified via online parameters detection and the system simulation is verified by an actual open lake source heat pump system. The actual energy consumption value and simulate energy consumption are with high consistency. The maximum difference is 7%. Based on this model, this paper discusses the effect of the surface water temperature, return water temperature, load rate, condenser pressure on the performance of water source heat pump system.With the goal of highest system energy efficiency, the optimization model of the surface water source heat pump is established and the optimal set values of control parameters are obtained.Based on the optimization model, an adaptive fuzzy PID control method of variable flowrate operation is put forward. The parameters of the control model are adopted by online detection method.The fuzzy PID controller adjust pump inverter frequency in real time and regulate the water pump flowrate to keep real-time water temperature difference and other parameters at the optimal value,thus achieve the optimal operation.In addition, taking a regional energy station project in Nanjing as an example,the overall energy-saving operation control strategy of the surface water source heat pump system is put forward,including heat pump unit control logic,optimization operation strategy in winter,water temperature forecasting model and load forecasting model. Finally, a weekday control strategy of the system has been analyzed and the result show a good energy-saving effect.