An approximate model of a multilayer wire-on-tube condenser operating with R134a and R600a: Experimental validation and parametric analysis

This study presents the development of a new approximate model for a multilayer wire-on-tube condenser used in the domestic refrigeration industry. This model is based on physical foundations and empirical correlations, as well as on the ε-NTU thermal analysis methodology. It has been designed for three zones according to the state of the refrigerant. The input parameters to the model correspond to typical geometric characteristics of this type of condenser and operating conditions. As output parameters, the emphasis was placed on the thermal capacity of the condenser, and the refrigerant side and air-side outlet temperatures. For its validation, tests were carried out with real refrigerators, one of them operating with R134a and the other with R600a. The model prediction showed maximum relative errors of ±5% for thermal capacity and ±0.5K for temperatures. Finally, a parametric study was carried out analyzing the effect of varying the main geometric parameters such as tube and wire diameters, and wire and tube pitches.