Carbon dioxide in ice rink refrigeration

Sammanfattning: The average energy consumption of one ice rink is around 1000MWh/year, which approximately69% is occupied by the refrigeration unit and heating demand. With the aim of decreasing theenergy consumption, a new concept of refrigeration system with CO2 as a refrigerant has beendeveloped and it is promising to become a high potential next generation for refrigeration systemin ice rink.This thesis is to evaluate a new refrigerant application in ice rink refrigeration system underthree different aspects; energy performance, heat recovery potential and economic efficiency. Inorder to make this evaluation, three main tasks are executed. Firstly, literature review and marketstatistic are processed to give a general picture of the CO2 development as a refrigerant. Secondly, asoftware Pack Calculation II is used for the simulations of CO2 refrigeration system and traditionalice rink refrigeration system. Älta ice rink located in Sweden, is chosen as a reference case forsimulation’s input data. The simulation results is to compare these system in terms of energyperformance and heat recovery potential. Finally, life cycle cost of these systems is calculated toinvestigate the economic benefits from this new application.Results from this study show good benefits of the new CO2 application in ice rink. Fromthe market statistics, CO2 has become a successful refrigerant in supermarket food and beverageindustry with 1331 CO2 refrigeration system installed until 2011 in Europe (Shecco2012). In icerink industry, 24 ice rinks have been applied CO2 in the second cycle of refrigeration system; oneice rink in Canada applied a refrigeration system with only CO2 in the first cycle and the distributionsystem.From the simulation’s result, CO2 full system has been proven as the most efficiency sys-tem with the lowest energy consumption (30% lower than NH3/Brine system and 46% lower thanCO2/Brine system) and the highest COP (6.4 in comparison with 4.9 of NH3/Brine system and4.37 of CO2/Brine system). Regarding heat recovery potential, CO2 full system has highest energysaving in comparison with the other two systems.Due to lower energy cost and service cost, the life cycle cost of CO2 full system is loweraround 13% than the traditional NH3/Brine system, furthermore, the component cost of CO2 sys-tem is promising to decrease in the next years thanks to the rapid development of this market insupermarket industry.To conclude, CO2 full system has high potential to become a next generation of refrigerationsystem in ice rink, however, because of its transcritical working, this application can be restrictedin the regions of warm climate.