Separation in condensers as a way to improve efficiency

This paper introduces the concept of separation of two-phase flow in condensers and discusses its possible application of enhancing the heat transfer performance by capitalizing on the high local heat transfer coefficient of vapor flow. The benefit of vapor–liquid refrigerant separation and the reason why it will improve the condenser performance are explained. Numerical studies are performed on an R-134a microchannel condenser. Model predicts that at the same mass flow rate, the exit temperature is lower by 1.3 K in the separation condenser than in the baseline condenser while the difference of pressure drop remains within 2%. 6.1% more flow rate of condensate is predicted in the separation condenser as another comparison criterion. In addition, the trade-off between high quality and low mass flux for the vapor path downstream of the separation header is investigated by the model and results are presented. Modeling is conducted with pre-assumed separation efficiency in the header. The real value requires further investigation.