Novel heat pump-based energy recycling system im swimming halls and sport arenas
Swimming halls and sports arenas are major energy consumers due to the indoor climate requirements and long opening hours. The specific heating energy consumption (kWh/m2 or kWh/m3) of swimming halls is one of the highest among all building types and the heating demand is substantial also during summertime. Due to the significant energy consumption required to maintain the targeted indoor climate conditions (temperature and relative humidity), domestic hot water temperatures and pool water quality, there are major waste heat flows that can be utilized. Various heat recovery applications have been used in swimming halls for decades, but they have mainly been sub-optimized system-specific solutions due to lack of engineering expertise and technological solutions available. The paper presents a novel energy recycling system application based on heat pump technology that is used for both heating and cooling of the swimming hall and sport arena complex located in Rauma, Finland. The system was originally designed in 2020–2021 and it has been operational since 2024. The system is a centralized large-scale heat recovery system utilizing heat pumps instead of several smaller application or system-specific solutions. The produced heat is utilized in all applicable heating networks. The implemented system collects waste heat from sewage water systems, pool rinse systems, exhaust air systems of the air handling units and cooling systems of the studied properties. For comparison, the collected waste heat amount is significant and equals to the heat content of a 64x310 meter optimally designed borehole field applicable to a densely populated city centre. Based on monitoring and measurements of the first six months of regular operation, the performance of the system is promising, although additional finetuning is still required. The developed energy recycling concept can also be implemented in renovations and used internationally.