Analysis of an internal heat exchanger (IHX) for vehicle air conditioning systems

Abstract In this study, an internal heat exchanger (IHX) was tested with R1234yf refrigerant according to data collected from a vehicle and then modeled one-dimensionally (1D) using Amesim software. The simulation results were verified with the test results, and the usability of R290 refrigerant in the same IHX was investigated with the model. Due to the higher enthalpy of R290, the desired performance was expected to be achieved with a shorter IHX, and the study was extended to include different IHX configurations. Therefore, the design of experiment (DoE) was created using the Taguchi-L16 orthogonal array, considering four IHX parameters at two levels. The Amesim model was run for 16 combinations, and the heat transfer provided by the IHX was calculated. Applying the signal-to-noise (S/N) analysis, the optimal design configuration was determined based on the larger-the-better performance criterion. Subsequently, the variance analysis (ANOVA) was performed to obtain the contribution ratios of each parameter to the heat transfer performance of the IHX. Finally, regression analysis was applied to develop analytical equations for predicting heat transfer as a function of the parameters. The heat transfer values calculated with the equations were compared with the simulation results, and a good agreement was obtained between them.