Maintaining an optimal water temperature is paramount in aquaculture. Traditionally, the selection of equipment to regulate water temperature in recirculating aquaculture systems (RAS) has been a complex process. This approach, which mainly relies on the volume of the fish tank, thermal parameter calculations, and aquaculture experience, often produces inaccurate results due to the influence of environmental factors, climate, and fish species.
Recognizing this limitation, a recent study developed by researchers at Dalian Ocean University (China) proposes the application of CFD (Computational Fluid Dynamics) simulation of the temperature field to accurately calculate the heat exchange value between indoor air and water. This allows predicting heat exchange values during aquaculture activities in RAS, providing a new approach for equipment selection.
What is Computational Fluid Dynamics (CFD)?
Computational Fluid Dynamics (CFD) is a technology that uses numerical methods to simulate fluid movement, heat transfer, and mass transfer processes. Compared to energy consumption calculations for traditional water temperature control equipment selection, CFD simulation can establish a more detailed mathematical model based on the real situation. It considers various factors affecting the temperature field, such as solar radiation, water temperature, workshop location, and outdoor temperature changes over time, thereby improving calculation accuracy.
A New Approach: CFD Simulation for Precision
To address these limitations, researchers have leveraged the power of Computational Fluid Dynamics (CFD) simulation. By accurately calculating the heat exchange between indoor air and water, CFD offers a precise method for predicting heat exchange values during aquaculture activities. This innovative approach provides a solid basis for selecting the most suitable water temperature control equipment.
By building a detailed 3D model that considers external temperature, solar radiation, and phase change heat transfer in the water, researchers have developed a powerful tool to optimize water temperature control.
Case Study: RAS for Pufferfish Farming
Selecting the right water temperature control equipment is crucial for the profitability and sustainability of recirculating aquaculture systems. Traditional methods often lead to oversized or undersized equipment, resulting in higher energy consumption and lower efficiency.
A recirculating aquaculture system for pufferfish farming in Dalian served as a test bed for this research. Researchers developed a 3D unsteady CFD model, incorporating external temperature, solar radiation, and phase change heat transfer in the water. The model’s accuracy was validated with experimental data, demonstrating a root mean square error of only 0.46°C.
Maximum Cooling Load and Equipment Recommendation
The simulation revealed that the highest cooling load occurs at 16:00 hours during summer, reaching a substantial 94.6 kW. Based on these findings, a Daikin GCHP-40MAH geothermal heat pump was recommended as the optimal water temperature control equipment. Post-installation CFD simulations confirmed the equipment’s effectiveness in shaping the indoor temperature field.
Key Benefits and Implications
- Greater Accuracy: CFD simulation provides a more accurate method for calculating heat exchange values, leading to better equipment selection.
- Cost Savings: Optimized equipment selection can reduce investment in water temperature control systems.
- Improved Fish Health and Productivity: Maintaining optimal water temperature is crucial for fish health and growth.
- Industry Advancement: This research offers valuable reference for the aquaculture industry in selecting water temperature control equipment.
By adopting CFD simulation as a tool for equipment selection, aquaculture facilities can significantly improve their operations, enhance fish welfare, and achieve greater sustainability.
Conclusion
The integration of CFD simulation in the selection of water temperature control equipment represents a significant advancement in modern aquaculture. The RAS study for pufferfish farming in Dalian demonstrates how this technology can transform efficiency and precision in aquaculture facility design, providing a model for future projects in the industry.
In this context, the main conclusions of the study include:
- CFD Model Accuracy and Efficiency
- Accurate Model: The developed 3D CFD model can simulate the air temperature distribution within a recirculating aquaculture workshop with high precision, considering factors such as external temperature, solar radiation, and water phase change.
- Successful Validation: Comparison with experimental data showed excellent agreement, validating the model’s effectiveness in describing temporal and spatial variations in air temperature.
- Thermal Load Identification
- Peak Thermal Load: The study determined that the maximum cooling load in the workshop during summer occurs at 16:00 hours, reaching 94.6 kW.
- Temperature Distribution: A fairly uniform temperature distribution was observed in the workshop due to natural convection.
- Optimization of Temperature Control System
- Accurate Equipment Selection: Using the CFD model to simulate air temperature after installing temperature control equipment allows for scientifically selecting the appropriate equipment.
- Reference for Other Workshops: The method employed in this study can serve as a reference for selecting temperature control equipment in other aquaculture workshops.
In summary, the study demonstrates the usefulness of CFD simulation as a tool to optimize the design and operation of aquaculture workshops, especially regarding temperature control.
Contact
Du Ping
College of Mechanical and Power Engineering, Dalian Ocean University
Dalian, Liaoning, China
Email: xu.ziyun00qq852741@hotmail.com
Reference (open access)
Ziyun X, Ping D, Jiacheng W, Leyao L, Kairui C (2024) Optimizing heat pump unit selection for recirculating aquaculture workshops through computational fluid dynamics. PLoS ONE 19(7): e0299997. https://doi.org/10.1371/journal.pone.0299997
