Abstract
Plate heat exchangers are widely used in the industry. Being compact in nature, they are good candidates to be used as evaporators with reduced charge. A review of the existing evaporation heat transfer coefficient data for plate heat exchangers has been carried out. The literature survey also includes compilation of available Nusselt number correlations. In this work, an attempt has been made to develop a universal Nusselt number correlation that can be used to predict the heat transfer coefficient during evaporation of several key refrigerants using various plate geometries. The predicted values of Nusselt number using proposed correlation were found to be in good agreement with the experimental data of ammonia (R-717), R-134a, R-410A and few relatively new refrigerants. The proposed correlation is valid for 313 < Reeq < 12,700, 0.000136 < Boeq < 0.0019 and is shown to predict the actual data within ±30% error. The predicted heat transfer coefficient was also found to be in good agreement with results from the major plate exchanger manufacturers.
