Optimal Operation of EHP for Reducing Energy Consumption in Recirculating Aquaculture Systems

Recirculating aquaculture systems (RAS) have high energy consumption because of the operation of various types of equipment.In particular, in facilities that cultivate warm-water species, boiler loads increase significantly during winter to maintain appropriate water temperatures under low outdoor air conditions.This load can be partially mitigated by heating indoor air through HVAC operations; however, reducing relative humidity increases water evaporation from tanks, and the inflow of replenished groundwater subsequently lowers water temperature, resulting in additional heating demand.Therefore, the energy consumption of aquaculture facilities must be comprehensively analyzed, accounting for both water temperature and indoor air conditions.This study investigates the application and operation of an electric heat pump (EHP) as an energy-saving strategy during winter in a recirculating aquaculture facility.For validation, measurements and verification were conducted by collecting field data on indoor air temperature and humidity, water temperature, dissolved oxygen, and electrical consumption.The calibrated model achieved an MBE accuracy level of -0.37% and a Cv(RMSE) of 11.9%.Based on this validated baseline model, an EHP system was integrated, and optimal operation strategies were derived based on indoor air temperature.This study demonstrated the potential to reduce energy consumption through HVAC applications in indoor aquaculture facilities, which are classified as energy-intensive buildings.