Steady-State Simulation of an Automotive Air Conditioning System Running on CO₂

This work presents a semi-empirical simulation of an automotive climate control system equipped with a transcritical vapor compression cycle running on carbon dioxide. The cycle components (a compressor, a throttling valve, an evaporator, a gas cooler, a suction accumulator and a suction line heat exchanger) were modeled to study the operation of the system, in the steady-state regime, under high ambient temperatures. The model took into account the severe conditions of tropical climates since the temperature at the inlet of the gas cooler is one of the predominant factors in the transcritical cycle performance. To assess the performance of the cycle, the thermodynamic model, reduced to a set of non-linear algebraic equations, was solved by a modified Newton-Raphson method. Reasonable agreement was found when results predicted by the model were compared with experimental data available in the literature.