Economic and performance analysis of heat pump system with renewable heat sources for recirculating aquaculture system (RAS)

Globally, seafood consumption is steadily increasing, driven by population growth and rising health awareness, with South Korea recording some of the highest per capita seafood consumption rates worldwide. This highlights the importance of sustainable aquaculture systems, such as the Recirculating Aquaculture System (RAS), which can recycle 90–99 % of aquaculture water, thereby reducing water use and mitigating disease and pollution risks. However, high initial investment and significant energy costs for maintaining optimal water temperatures hinder widespread adoption. To improve economic and energy efficiency, this study evaluates heat pump systems utilizing various natural heat sources (seawater, air, ground) in comparison to conventional boiler–chiller systems for commercial-scale RAS facilities. Using TRNSYS dynamic energy simulations, the research assesses each system’s thermal performance, energy consumption, and operational cost. In addition to energy and maintenance savings, this study introduces a profitability assessment framework by estimating annual revenue from fish production and calculating key economic indicators such as payback period and net profit. Results show that while the ground-source heat pump (GSHP) offers the highest energy efficiency, the seawater-source heat pump (WSHP) achieves the best overall balance between initial investment and operational profit. The findings aim to provide practical insights for selecting optimal heat source systems, reducing the total cost of ownership, and supporting sustainable growth and renewable energy integration in the aquaculture industry.