CFD analysis of Vaccine cold Storage warehouse HVAC System

A vaccine storage facility being constructed by Agility Pharma Logistics in Saudi Arabia requires an in-depth investigation of airflow dynamics and cooling processes within the warehouse through CFD analysis. To address this need, the contractor responsible for the cooling system has engaged Niharika Computational Engineering Solutions Pvt Ltd to perform a thorough CFD analysis and evaluate the air distribution in the proposed ducting system. The project scope includes the creation of a 3D CAD model as needed for the CFD analysis, the generation of a CFD mesh, and the execution of a detailed CFD analysis to assess flow development.

The HVAC contractor has developed an air jet impingement cooling system utilizing traditional engineering calculations. This system requires evaluation of its effectiveness through Computational Fluid Dynamics (CFD) analysis. Ensuring that air reaches all areas where vaccines are stored and maintaining a uniform temperature are critical requirements. The primary goal of the CFD analysis is to examine the flow characteristics within the impinging nozzle system and the resulting temperature distribution.

The NCES team develops a detailed three-dimensional (3D) CAD model suitable for Computational Fluid Dynamics (CFD) analysis, using the available two-dimensional (2D) AutoCAD drawings as the primary reference. The model is created using PTC Creo CAD software, translating the original engineering drawings into an accurate three-dimensional representation of the warehouse geometry and HVAC system. During this process, the geometry is reviewed and simplified where necessary to eliminate insignificant details while preserving the essential features that influence airflow and temperature distribution. The resulting 3D CAD model provides the foundation for computational mesh generation and subsequent CFD simulations, enabling the team to evaluate the HVAC systems performance and identify potential airflow distribution and thermal uniformity issues.

A poly-hexcore computational mesh is generated for the simplified 3D CAD model to ensure accurate and efficient resolution of the airflow and heat transfer characteristics within the warehouse HVAC system. The mesh is locally refined around the supply air duct nozzle units and in regions where steep velocity, pressure, and temperature gradients are expected, enabling better capture of complex flow behavior and air distribution patterns. The overall mesh consists of approximately 16 million cells, providing a suitable level of spatial resolution for analyzing the system's performance. The mesh quality is assessed using relevant quality metrics to ensure compliance with established CFD best practices and to support numerical stability, convergence, and reliable simulation results.

The initial CFD analysis revealed that certain enhancements were required in the nozzle distribution header to achieve a more uniform distribution of supply air across the warehouse. The simulation results helped identify potential flow imbalances within the header that could affect the airflow rate through individual nozzles and consequently influence the overall cooling performance. Based on these findings, the NCES team worked closely with the Client team to evaluate the existing configuration and implement suitable design modifications. The revised header design was subsequently assessed to improve airflow distribution and ensure more consistent delivery of cooling air throughout the storage area. This collaborative, simulation-driven approach helped optimize the HVAC design and enhance the overall effectiveness of the air-jet impingement cooling system.

The temperature distribution within the vaccine storage warehouse is evaluated across multiple sectional planes to assess the effectiveness of the HVAC system in maintaining thermal uniformity throughout the storage area. The CFD results indicate that a relatively uniform temperature distribution is achieved within the designated storage zone, demonstrating the effectiveness of the optimized air distribution system in delivering consistent cooling. However, marginally higher temperatures are observed near the ceiling, primarily due to the influence of solar radiation and the associated heat gain through the roof. These localized temperature variations highlight the importance of considering external thermal loads when designing cooling systems for temperature-sensitive storage facilities. Overall, the analysis provides valuable insights into the warehouse thermal performance and helps verify the effectiveness of the HVAC design in maintaining consistent storage conditions.