Effect of mixture composition on the formation of pinch points in condensers and evaporators for zeotropic refrigerant mixtures

摘要

In a recent study, it was shown by the authors that perfect glide matching of heat transfer fluid and the refrigerant is difficult in condensers and evaporators for many zeotropic mixtures and also that pinch points can occur in both thecondensers and evaporators due to the non-linear variation of enthalpy during phase change. Also, a simple method was presented for predicting the occurrence of pinch points. In this paper, the influence of mixture composition on occurrence of pinchpoints is studied. From the thermodynamic analysis, it is shown that multi-component mixtures are preferable over many wide boiling binary mixtures for various applications from the point of view of pinch points and glide matching. The results areillustrated with a number of examples.