Study On The Factors Influencing The Heating And Cooling Capacity Of Lake Water Heat Pump System

As a new renewable energy technology and be characteristic ofenergy conservation, high efficiency, environmental protection andmulti-purpose, surface water heat pump has been adopted more and morein engineering. However, the influence of temperature distribution, waterof low rate, water quality, temperature difference between water inlet andoutlet on heat pump system was not taken into full consideration duringthe designing period. As a result, the heat pump system got a lowerefficiency or even stopped running, which limited the popularization andapplication of surface water heat pump system.Taking a surface water heat pump system in Zhuzhou for example,factors that influence the heating and cooling capacity of water heat pumpsystem were studied by means of experiment and numerical simulation.Research status of water heat pump system, the mathematical model ofwater temperature distribution and the heating-cooling capacity werereviewed at home and abroad. Based on that, Two-dimensional watertemperature model was established by adding mass source term andenergy source term to the governing equations, and the accuracy of themodel was testified by the experiment. Then by employing the k-eturbulence model, temperature distribution of the lake water under threedifferent water taking and draining methods was simulated and analyzed，based on which, the maximum heat capacity of the lake with differentdepths was determined.The results showed that the water temperature increased by time andthe thermal stratification of water diminished gradually after the40-day,80-day and120-day continual operation of the heat pump system, whichis in good accordance with the reality. And it had been proven that themarch-past water-taking method was better than another two methods, bycomparing the three kinds of water-taking methods. And the extremewater-taking temperature of the heat pump system in eastern Hunan wasproven to be33℃by comparing the draining-water temperature of theheat pump system and the cooling tower. And the results showed that the maximum heating or cooling capacity of the heat pump system increasedwith the increase of the water depth. Finally, the simulation results werefitted with one dimensional non-linear regression equation and therelationship between the maximum heating or cooling capacity and themean water depth was presented.