Study On The Energy Efficiency Balance Point Of Water-Cooled Multi-connected Air-Condition System

The water-cooled multi-connected air-condition system whose multi-air-cooled condenser is replaced by multi-plate water-cooled condenser is a relatively new air-conditioning system. This work is mainly focused on the theoretical analysis and experimental study of the operating characteristic and energy efficiency balance point of the water-cooled multi-connected air-condition system.First of all, through the research of the structure, operation and other aspects of the multi-connected air-condition system based on systematic thinking to provide methodology of guidance for the research of this system. The relationship between condensing temperature and performance of refrigetation is confirmed by theoretical calculation. To the frequency compressor, the relationship between the inlet temperature and temperature difference of the condenser using different cooling agent (air or water) and the cooling energy efficiency of the refrigeration system is obtained, to provide a theoretical basis for the study of energy efficiency balance point.The test-bed of air-cooled heat pump and water-cooled multi-connected air condition system is put up to test its actual operating conditions in summer. The effect of different conditions on this system performance as well as the practical operation energy efficiency ratio of the system in Qingdao is studied.The relationship between air temperature and water temperature of the water-cooled multi-connected system which use ground source, sea water or cooling tower water is obtained through analysing the commonly used cooling water temperature characteristics in Qingdao.On the basis of characteristics of the water-cooled multi-connected system, an idea about evaluating the system's application is put forward. The mathematical model of the energy efficiency balance point between water-cooled and air-cooled multi-connected air condition system is established, also the energy efficiency balances of different sizes of the office buildings are calculated. Finally, the radius of applicating the water-cooled system is more energy-saving than air-cooled system are obtained.By researching the energy efficiency balance point of the water-cooled multi-connected air condition system, the theoretical basis for energy conservation of the system can be given and it also can provide a basis for the system's practical application and its design and engineering applications.