摘要：The EU F-gas regulation of 2006 and the recast of 2014 are forcing the market to reduce the use of refrigerants with high global warming potential (GWP). As a result, the production of hydrofluorocarbon (HFC) refrigerants with higher GWP decreased, making the prices of all HFC gases to increase. Any maintenance problem in a refrigeration system asks to evaluate the retrofitting of the gas making necessary to know the expected behaviour of the system. This paper aims to discuss the gases that can substitute the now-a-days HFCs, and the impact the retrofit will cause in a real air-conditioning systems. Many studies on retrofit address the behaviour of the refrigeration cycle, but usually, do not take into account the behaviour of the system as a whole. This paper models a water-to-water air-conditioning system taking into consideration the evaporator and condenser heat exchangers, the refrigeration cycle, the air-conditioning loop and the heat exchanger to the acclimatized area. Moreover, the paper studies the performance of the system when subjected to high condensing temperatures. The paper concludes that all possible retrofit solutions need to use flammable gases that make the refrigeration power of the equipment to reduce.
