Study On Characteristics Of Fresh Air System Based On Ground Source Heat Pump Capillary Radiation Air Conditioning

The air conditioning system with ground source heat pump and capillary terminal devices is one form of temperature and humidity independent controlling system, which is becoming popular as energy-saving, eco-friendly, fine thermal comforting and space-saving. Fresh air system is an important part of the radiation air conditioning system. Fresh air undertakes indoor moisture load as well as meets demand of the indoor health, but also. Reasonable design of fresh air system is the key to stable operating of radiation air conditioning system. Meanwhile, radiation air conditioning system is mostly applied in low energy consumption building, which attributes to higher proportion of fresh air load in the total air conditioning load compared with the conventional air-conditioning system. The results show that fresh air load accounts for about55%～70%of the total load in radiation air conditioning system. While in the conventional system, the proportion is25%～40%. The key of widely promoting capillary radiation air conditioning is to reduce energy consumption of fresh air and search better cooperation between fresh air and capillary radiation terminal. This paper mainly studied the calculating methods for fresh air volume and air supply parameters of radiation air conditioning, characteristics of different fresh air handling processes, energy consumption and effects of soil heat balance by buried heat exchanging system.The constitutions, working principles and advantages of ground source heat pump coupling capillary radiation terminal air conditioning system are studied in this paper. And the calculating methods for fresh air volume and air supply parameters are studied in radiation air conditioning system applied to three types of buildings i.e. office, hotel and residence.Meanwhile, the energy consumption models of cooling dehumidification, rotary dehumidification and liquid desiccant systems are presented in this paper. As is shown in the results, in term of renewable energy, the energy consumptions both for rotary and liquid desiccant system are high if high grade electricity instead of low grade energy such as solar energy, geothermal energy and industrial waste heat is used for regeneration. The total energy consumptions for rotary and liquid desiccant system are1.54and1.52times of the cooling dehumidification system, respectively.Three different ways of fresh air dehumidification applied to a residential building in Nanjing are investigated in this paper. The calculating results show that, balance rate of soil heat for cooling dehumidification system, rotary dehumidification system and solution dehumidification system is52.5%,27%and6.5%, respectively under24hours operating mode, and33.5%,0.8%and-46.9%, respectively under16hours operating mode.At the same time, a testing platform of cooling dehumidification fresh air handling unit is also set. Effects of unit performance changing with fresh air temperature, return air temperature are analyzed. Experimental results show that suction pressure and discharge pressure rise with the increase of fresh air temperature. While heating capacity of heat pump and COP drops2.77%and2.03%with per1℃increasing of fresh air temperature, respectively. The decreasing return air temperature attributes to dropping of power consumption of compressor, heating capacity of unit, and COP. The heating capacity of heat pump and COP drops2.77%and2.03%with per1℃of return air temperature decreasing, respectively.