Vapor−Liquid Equilibrium Study of an Absorption Heat Transformer Working Fluid of (HFC-32 + DMF)

Abstract

The absorption heat transformer (AHT) is an important energy-saving device that can be driven by low-grade energy. In this work, the mixture of difluoromethane (HFC-32) and N, N -dimethylformamide (DMF) is considered as a promising new working fluid for AHTs. Vapor−liquid equilibrium data for (HFC-32 + DMF) were measured over the temperature range from (283.15 to 363.15) K using an equilibrium apparatus with continuous vapor-phase circulation. Throughout the overall experiment, there was no stratification or sediment generation, and the color of the liquid in the equilibrium cell was the same before and after the experiment. The above-mentioned results suggest that any ratio of HFC-32 and DMF could be miscible. The experimental data were correlated using the NRTL model. The average relative deviation of the pressure was 1.65 %, and the maximum relative deviation of the pressure was 4.24 %. The calculated results showed good agreement with the experimental data. It is shown that the mixture exhibits a negative deviation from Raoult’s law.