Working fluids for an absorption system based on R124 (2-chloro-1,1,1,2,-tetrafluoroethane) and organic absorbents

• Published in: International journal of refrigeration 1997, Vol.20 (4), p.256-266
• Main Authors: Borde, I, Jelinek, M, Daltrophe, N.C
• Format: Article
• Language: English
• Subjects: absorbant; absorption machine; Applied sciences; chemical composition; composition chimique; COP; Devices using thermal energy; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Heat pumps; machine à absorption; measurement; mesure; propriété thermodynamique; R124; Refrigerants; Refrigerating engineering; Refrigerating engineering. Cryogenics. Food conservation; thermo-dynamic property
• ISSN: 0140-7007; 1879-2081
• DOI: 10.1016/S0140-7007(97)00090-X

The possibility of using R124 (2-chloro-1,1,1,2,-tetrafluoroethane, CHClFCF 3) and organic absorbents as working fluids in absorption heat pumps was investigated. Various classes of organic compounds, all commercially available, were tested as absorbents for possible combination with R124; the absorbents included DMAC ( N′, N′-dimethylacetamide, C 4H 9NO), NMP ( N-methyl-2-pyrrolidone, C 5H 9NO), MCL ( N-methyl ϵ-caprolactam, C 7H 13NO), DMEU (dimethylethylene urea, C 5H 10N 2O), and DMETEG (dimethylether tetraethyleneglycol, C 10H 22O 5). To evaluate the performance of a candidate refrigerant-absorbent pair in a refrigeration or heat pump cycle, the thermophysical properties of the pure components and the mixture and the equilibrium and transport properties have to be determined, either from experimental data or by prediction methods. The thermal stability of the refrigerant-absorbent must also be tested. A method for the calculation of the concentration in the liquid and gas phases and the excess thermodynamic properties of the mixture as a function of the system temperature and pressure based on our experimental setup is described. On the basis of vapor-liquid equilibrium measurements, density and viscosity measurements and thermostability testing, enthalpy-concentration diagrams were constructed. The performance characteristics of the investigated working fluids in terms of the coefficient of performance (COP) and the circulation ratio (f) were calculated for a single-stage absorption cycle. In terms of overall performance (COP, f and stability) R124-DMAC was found to be the superior combination, followed by R124-NMP, R124-DMEU and R124-MCL (the three pairs for which stability problems were found at high temperatures), and finally by R124-DMETEG. On a étudié la possibilité d'utiliser le R124 (2-chloro-1,1,1,2-tétrafluoroéthane, CHClFCF 3) et des absorbants organiques comme fluides actifs dans des pompes à chaleur à absorption. On a essayé différentes catégories de composants organiques, tous commercialisés, comme absorbants pouvant être associés au R124. Il s'agissait des produits suivants: le DMAC (N,N′-diméthylacétamide, C 4H 9NO), le NMP (N-méthyl-2-pyrrolidone, C 5H 9NO), le MCL (N-méthyl ϵ-caprolactam, C 7H 13NO) le DMEU (de diméthyléthylène urée, C 5H 10N 2O) et le DMETEG (diméthyléther tétraéthylène-glycol, C 10H 22O 5). Pour évaluer la performance d'un couple frigorigène-absorbant dans un cycle frigorifique ou de pompe à chaleur, il faut déterm