Working fluids for high temperature sorption cycles
Abstract Sorption cycles could be used in industrial processes to lift waste heat available at temperatures from ≈ 100 to > 200°C. Three different organic working pairs have been tested within these boundary conditions. Each pair has hexafluoroisopropanol as refrigerant. Quinoline and n-methylpyrrolidone are used as absorbents. Vapour-liquid equilibrium measurements in the range 0.1–20 bar† and 25–250°C as well as caloric measurements, estimates of specific volumes and thermal stability tests are reported. It is shown that due to stability problems only one of the working pairs can be used for the whole temperature range considered. The technical data for a conventional and an inverse absorption heat pump cycle are calculated, figures are presented and conclusions drawn for both applications.