Study On Heat Transfer And Refrigeration System Of Ice Rink Using CO₂ As Coolant

Beijing’s successful bid for the 2022 Olympic Games heralds a new chapter in China’s ice and snow industry.As a building with high energy consumption,the ice rink has great potential in energy saving and environmental protection.Moreover,people have put forward new requirements for the environment,such as carbon neutral,carbon peak and other new concepts.Therefore,it is necessary to reuse CO₂ under the requirements of meeting the environmental requirements.In terms of the heat transfer law of the ice rink,this paper simulated the heat transfer of the ice rink,and studied the effects of ice surface temperature,cooling pipe spacing,cooling pipe diameter,distance above the cooling pipe,insulation layer material and thickness and region on the heat transfer law of the ice rink.The results showed that:When the ice surface temperature is-3～-5℃,the summer heat flux and evaporation temperature of the cooling pipe are 287.02～298.86W/m² and-29～-32℃,respectively.In summer,when the distance between the cooling pipes increases by 10mm,the heat flux of the cooling pipes required increases by 28～39W/m²,and the evaporation temperature decreases by 1.2～1.5℃.In summer,the evaporation temperature of working medium in the cold pipe increases by 2.88℃and the heat flux decreases by 49.4W/m² for every 5mm increase in the diameter of the cold pipe.When the distance above the cold pipe increases by 1mm in summer,the evaporation temperature of the working medium in the cold pipe decreases by 0.99℃,and the heat flux increases by 0.17W/m².When the thickness of the insulation layer increases from 0mm to 30mm,the heat flux of the cold pipe changes sharply,and then increases from30mm,the heat flux of the cold pipe gradually decreases.In the temperature cloud map of10m underground,in terms of temperature distribution,the soil temperature of the ice rink in Harbin has the lowest distribution,while that of Guangzhou has the highest.In terms of temperature change,the change of underground soil temperature in Chongqing area is the least,and the effect of frost heaving is the least,while the change of soil temperature in Guangzhou area is great,and the effect of frost heaving is great.In the aspect of CO₂refrigeration system,the annual energy consumption calculation model of the ice rink refrigeration system was established.In the refrigeration system under summer working conditions in the same area,the direct COP was about 49%～171.6%higher than that of the indirect one.The COP of CO₂ carrier is about 3.2%～8.3%higher than that of brine carrier.The COP of the two-stage compression system with CO₂ as coolant is about 4.4%～20%higher than that of the single-stage compression system.According to 8 typical cities in China,the energy consumption of CO₂ and NH₃ ice rink refrigeration system is compared.The results show that:In terms of energy consumption comparison,the compressor,condensing fan,refrigerant carrier pump and total energy consumption of each refrigeration system have the same distribution law,and Guangzhou>Chongqing>Changsha>Shanghai>Zhengzhou>Xi’an>Beijing>Harbin,and the higher the latitude,the smaller the energy consumption,the more obvious advantages of CO₂ refrigeration system.Figure 46;Table 15;Reference 62...