Vapor–liquid equilibrium measurement of 1,1,1,3,3-pentafluoropropane + N,N-dimethylformamide/diethylene glycol dimethyl ether/N-methyl-2-pyrrolidone working fluids for absorption power cycle

• This work proposed 3 potential working fluids for absorption power cycle.
• The vapor–liquid equilibrium data of the three systems have been measured over a temperature range from 293.15 to 353.15 K and pressure over 15–800 kPa.
• Based on the molecule structure and the hydrogen bond interacted between the molecules, we analyzed the discrepancy of the affinity of the three binary systems.

According to previous investigation on organic rankine cycle (ORC) and absorption refrigeration cycle, this work chose three potential working pairs for absorption power cycle. They are 1,1,1,3,3-pentafluoropropane (R245fa) + N,N-dimethylformamide (DMF)/diethylene glycol dimethyl ether (DMEDEG)/N-methyl-2-pyrrolidone (NMP). The vapor–liquid equilibrium (VLE) data of the three systems have been measured under a temperature range from 293.15 to 353.15 K and pressure range from 15 to 800 kPa. The experimental data were correlated using the five-parameter non-random-two-liquid (NRTL) model. The average relative deviations between the experimental data and the calculated data are 1.52%, 1.92% and 1.81%, respectively, and maximum relative deviations are 4.03%, 4.05% and 3.97%, respectively. The affinity of the three systems has been compared under the different conditions of 303.15 K and 323.15 K. Result shows that the solubility of R245fa in DMF and DMEDEG is similar while the solubility of R245fa in NMP is smaller. In addition, the affinity between R245fa and the three absorbents was also discussed based on the molecule structure and the hydrogen bond interacted between the molecules.