Heat transfer in pool boiling of ammonia-water mixture

Abstract

The nonazeotropic binary mixtures such as, methanol-water, ethanol-water and ammoniawater, have variable boiling and dew points, depending on the mixture components and those concentrations. It is expected to have a higher coefficient of performance as a result of decreasing the thermodynamically irreversible loss, when there is a relevant concentration. Therefore, ammonia -water mixture is used as working fluid in small temperature difference power generation cycles and absorption refrigeration cycles. However, few experiments were carried out for measuring heat transfer coefficient for ammonia-water mixture in the world. Therefore, an experimental study has been carried out to measure boiling heat transfer coefficient of an ammonia-water mixture on a horizontal heated surface at low pressure of 0.2, 0.4 and 0.7MI'a and at low concentration of 0< C<0.5 and at high pressure 0.7, 1.0, 1.5 MI'a and at concentration of 0.5< C< 1.0 and at heat flux under critical heat flux the heat trasfer coefficient are compared with existing correlations •prediction and a revised correlation can be proposed to predict them well.