Study On Control Strategies For Heat Pump System With Hybrid Of Cooling Tower And Ground Source

Heat Pump Air-Conditioning system with hybrid of cooling tower and ground source cooling water system is studied and applied widely around the world because of its steady performance, high efficiencey, energy saving, and environment friendly, however, its performance depends on the control strategies. So, the study about the control of Heat Pump Air-Conditioning system with hybrid of cooling tower and ground source cooling water system has being one of the most hot problem in Ground Source Heat Pump area.So far, the research method about control of Heat Pump Air-Conditioning system with hybrid of cooling tower and ground source cooling water system is mainly by the simulation of specific system on the conditon of typical year’s parameter which lacks analysis of meteorological parameter. It conduces to that outdoor’s weather condition is under-utilised. Synchronously, the existing control stategys don’t connect with dynamic building load.Their flexibility is bad in the actual motion, and can not always reach the aim that make the system get the highest integrate energy efficiency on the premise of ensuring annual ground heat energy balance. So, the system which runs with the controlling by the existing control stategys probably loses its characteristic of steady performance and energy saving.The article mainly analysed the shortages of the existing control strategies firstly.An evaluation methodology used to evaluate the strategies’control effection is put forward and the article analysed the factors which influnent the effects of the system’s controlling in theory, and then it put forward a dynamic control stategy,Time Interval with Temperature Difference Control(TITDC).The article put up some simulation modles using the TRNSYS simulation software to simulate the running of a specific Heat Pump Air-Conditioning system with hybrid of cooling tower and ground source cooling water system controled by different control strategy. The performance of TITDC on all the critical parameters, such as annual ground heat energy balance, system running energy consumption, control strategy robust and load satisfied percentage for long term, are compared with conventional control strategies.The article developed a control system used to control the He Fei south railway stayion’s Heat Pump Air-Conditioning system which used the TITDC as the control strategy. The control system can reach the aim that make the air-conditioning system get the highest integrate energy efficiency on the premise of making the annual ground heat energy balance.On the basis of the research and analysis above, the article came to some conclusions and gave some advices about running control of Heat Pump Air-Conditioning system with hybrid of cooling tower and ground source cooling water system finally.