Simulation-Driven Improvement of Temperature Linearity in Dual Layer HVAC Systems

The Heating, ventilation, and air conditioning (HVAC) industry is rapidly growing, particularly in the automotive sector since they are integral to maintaining passenger comfort in vehicles by regulating the internal temperature. This growth has led to an increased demand for highly optimized and efficient HVAC systems for a uniform temperature distribution in vehicles. However, achieving this in the cabin remains a challenge due to the complex airflow dynamics within the HVAC system. A critical factor in ensuring uniform temperature distribution for year-round performance is maintaining temperature linearity within specified limits, which is essential for user comfort. Temperature linearity refers to the temperature differential between duct outlets when air is distributed through multiple vents, such as those aimed at the face and feet. This differential typically ranges from 15°C to 20°C, varying based on customer and manufacturer specifications. The flap angle significantly influences this temperature difference, as it regulates airflow through the heater according to user needs. This research investigates the potential for improving the temperature linearity of a vehicle HVAC system through geometry modifications in key components such as air ducts, and flaps. This is achieved through computational fluid dynamics (CFD) simulation in STAR-CCM+ software for various different geometric configurations in order to have the values of temperature linearity within limits throughout varying flap angles of vehicle HVAC system. The research's findings aim to enhance user comfort while also advancing the creation of cutting-edge HVAC systems that satisfy performance and efficiency requirements set by the industry. Through tackling the issues of temperature linearity in these systems, this research offers significant perspectives for upcoming advancements in car climate control technology.