A dynamic computer simulation model for automobile passenger compartment climate control and evaluation

The traditional development of a vehicle climate control system relies heavily on the extensive and expensive experimental approach. A Computer Aided Engineering (CAE) model is needed to provide engineers with an effective and inexpensive analysis tool for designing, developing, and optimizing the vehicle climate control system over a wide range of operating conditions. To meet this need, a computer simulation model has been developed to calculate the temperature and humidity variations inside the passenger compartment while simulating the performance of the automotive Air-Conditioning (A/C) system.; The vehicle has been divided into two linked modules representing the A/C network and the passenger compartment climate. An A/C system consisting of major components such as the evaporator, compressor, condenser, orifice, air handling system, and connecting hoses are included in the study. Pressure drop and thermal capacity for the evaporator, condenser, and connecting ducts/hoses are accounted to yield a realistic simulation. To perform system benchmark comparison and parametric study in an overview fashion, the passenger compartment climate was designated using the lumped capacitance method. It is assumed that the temperature and humidity inside the passenger compartment is spatially uniform at any instant of time during the simulation. In addition, a lumped analysis of the interior masses such as seats, instrument panel, floor console, etc., are also included in the analysis since they act either as heat sources or sinks. The thermal loads including solar, conductive, and convective heat loads on the passenger compartment and the energy storage within the vehicle wall were evaluated based on fundamental physical principles with the correlations available in the literature.; The transient nature of the passenger cabin average temperature, the seat average temperature, and the average humidity were modeled using three coupled non-linear ordinary differential equations based on mass balance and energy balance. These equations were then solved by a fourth-order Runge-Kutta method with adaptive step-size control.; The results obtained from the simulation model are in good agreement with the experimental data for both the A/C system and the cabin climate. Parametric studies further demonstrate that using a computer simulation model developed in this study can expand and enhance the design capacity with the advantages of cost and time savings.