A three-zone model, based on the desuperheating, condensing, and subcooling sections of a mobile air conditioning condenser, was developed from a least-squares analysis of experimental data. Since the model was developed to simulate a mobile air conditioning system, the inlet refrigerant pressure and temperature, refrigerant mass flow rate, inlet air temperature, and air flow rate were all treated as independent variables to the model. The outlet refrigerant temperature and pressure and the outlet air temperature were the dependent variables. The overall heat transfer coefficient for each of the three sections, expressed as a function of the air velocity across the condenser and the refrigerant mass flow rate, and the length of each section were determined using energy equations for each section. To include the pressure drop within the condenser model, a momentum equation was used to determine the friction factor as a function of the refrigerant mass flow rate for each section. The model predictions, based on the inputs to the model, were compared to the experimental data and were found to agree within 2% for the overall heat transfer rates and 20% for the overall pressure drop.

KEYWORDS: calculating, steady state, air conditioning, motor cars, condensers, heat transfer coefficient, fluid flow, refrigerants, heat flow, pressure drop