Various waste heat recoveries and potential energy savings in an ice hall in Finland

Ice rinks can generate lots of low-grade waste heat while consuming huge amounts of energy, which can be re-utilized for various heating demand (e.g., supply air, DHW and ice resurfacing hot water heating, water radiators and ground frost protection), otherwise waste heat will be directly discharged to the outside, which will cause energy waste and thermal environmental pollution. This article proposes applying three kinds of available waste heat sources (e.g., gray water, ice refrigeration process, condensing heat from air dehumidification process) for waste heat recoveries in and for the ice hall itself. The system adopted thermal storage tanks for storing the waste heat, and high-temperature exhaust air heat pumps are used to rise the temperature levels of waste heat for higher heat demands. After analyzing the the simulation results, it shows that waste heat recoveries can replace up to 99% of the purchased district heat, but just increase the purchased electricity cost by only 9%. Besides, waste heat utilization can reduce the total energy use by 58%, and annually save energy cost by 45% (around 82 k€) considering the summer breaks. In addition, during the three repayment periods (7, 10, 15 years), the maximum energy cost savings range from 510 to 970 k€ in difference cases.