Comparative Analysis of Modern Energy Systems for Ice Rinks

Abstract: Ice rinks are highly energy-intensive commercial buildings with an average annual energy consumption of 1,000 MWh, most of it being used to cover the simultaneous heating and cooling demands. The aim of this thesis is to find the most energy efficient energy system for ice rinks by evaluating different system modifications and refrigerants. A comparative analysis of ammonia, CO2 and propane energy systems based on a representative ice rink for northern climates has been conducted. A traditional integrated ammonia ice rink consumes about 340 MWh per year to cover the thermal demands. The most promising energy efficiency measures for ammonia are using aqua ammonia as the secondary fluid and using an auxiliary heat pump to aid with covering heating demands. Thanks to these measures, energy savings of 12.9% can be achieved. A state-of-the-art trans-critical CO2 system using parallel compression consumes approximately 42.6% less energy than a conventional ammonia system, making it the most energy efficient solution for ice rinks with an SPF of 7.5. The good performance is largely linked to the possibility of operating CO2systems as direct systems, eliminating the need for indirect heat transfer and minimizing auxiliary equipment energy consumption. Propane, which has not been investigated as a refrigerant in ice rinks yet, was evaluated and compared against ammonia and CO2. A modern integrated propane system using parallel compression and an auxiliary heat pump is more energy efficient than a traditional ammonia system but requires more energy than modern ammonia or CO2 systems. Propane proved to be feasible and represents a potential alternative solution in ice rinks. Waste heat recovery is beneficial in every system and should be a key feature in ice rink energy systems. All systems use environmentally friendly refrigerants and their environmental impact is almost exclusively indirect and caused by electricity consumption.