Operation optimization of a hybrid water-source heat pump system of groundwater combined with seawater based on orthogonal experiment method

Combining with an actual project in Tianjin port, presents the mathematic model of the water-source heat pump unit and performs the experimental verification. The results show that the simulation results and experiment results are in good agreement, and the model can be used to obtain and forecast the operation characteristics of the units. Bases on the model, optimizes the annual operation strategy of the hybrid heat pump system by orthogonal experiment method. The optimized operation strategy is that during the heating period, the seawater-source heat pump system operates singly when the seawater temperature is higher than 8 ℃, and the groundwater heat pump system operates in the other times; and during the cooling peiod, the seawater-source heat pump system operates singly when the seawater temperature is lower than 6 ℃, and the hybrid water-source heat pump system operates in the other times. Water pumps with variable frequency are used on the cooling/heating water pipeline. For the optimal operation strategy, the imbalance ratio between the cooling and the heating load is 3.57%, satisfying the demand of design standard.