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

The HVAC industry is rapidly expanding, particularly in the automotive sector, fueled by India's recent air conditioning mandate. This growth has led to an increased demand for highly optimized and efficient HVAC systems in vehicles. A critical factor in ensuring 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 13 to 15°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 study aims to design an HVAC duct system that effectively maintains optimal temperature linearity across varying flap angles. We employ computational fluid dynamics (CFD) simulations to analyze the temperature linearity of a baseline duct geometry. Initially the temperature linearity was greater than 20°C at certain flap angles but after various number of iterations, design modification and geometry optimization the temperature linearity was brought back well within limits. The prototype based on this improved design after various testing was proven successful. 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 HVAC systems, this research offers significant perspectives for upcoming advancements in car climate control technology. This version successfully highlights the study's goals and methods while keeping a technical focus and being succinct and understandable.