Heating, ventilation and air conditioning systems play a crucial role in our day-to-day activities. With rise in global warming, leading to climate change, HVAC unit is the need of the hour. With average temperatures on the rise, it is quite imperative that the unit provides better thermal comfort to the passengers. Off-road vehicles like tractor, is also no exclusion. Tractor drivers have to experience adverse weather conditions out in the open field. Thus it is quite fundamental that sufficient airflow reaches every point inside the driver cabin, ensuring proper cool-down. To ensure proper distribution of airflow inside the cabin, optimization of HVAC unit needs to be properly carried out.
The present study shows how an HVAC of an off-road vehicle is properly optimized with the help of Computational Fluid Dynamics. STAR-CCM+ v2021.2.1 is used as solver for the simulation. Airflow simulation of inside cabin is also carried out in both initial and optimized design and cooldown simulation is done on optimized design. The simulation flowchart is carried out in 3 steps. At first, a steady-state airflow analysis is conducted in an HVAC. Secondly, a steady-state airflow analysis is ran in the entire cabin. The velocity distribution from duct exit, obtained from first step is taken as an input boundary condition in the second step. Thirdly, a transient thermal run is conducted in the entire cabin. The transient temperature distribution of duct exit obtained from testing is feeded as input boundary condition in software. The above-mentioned steps are followed in optimized design. Improvement in airflow is observed in the optimized design, leading to a better cooldown. The CFD results were correlated with experimental result with good trends observed between them.