Prediction of heat transfer during condensation of carbon dioxide in channels

There is currently great interest in the use of CO2 as a refrigerant and hence a reliable method for predicting heat transfer during condensation in channels is needed. This research was done to evaluate the applicability of available predictive techniques. A number of correlations, including three very recently published correlations, were compared with a database that included all test data that could be found. These include single tubes and multichannels with diameters of 0.15-22.1 mm, evaporation temperatures of −25 °C to 29 °C, mass flux of 50-1000 kg/m2s, and vapor qualities of 0.02-0.97. One of the general correlations gave good agreement for mass flux up to 300 kg/m2 s. None of the other correlations gave good agreement with data at any flow rate.