Conference Year
2018
Keywords
GWP, Equation of state, NIST, RE170, Thermodynamic properties
Abstract
This paper deals with the theoretical development of thermodynamic properties of an environmental friendly refrigerant dimethylether (RE170). Since hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) are going to be phase out and phase down as per Montreal and Kyoto protocol respectively. Refrigerant RE170 has zero ozone depletion potential (ODP) and very low global warming potential (GWP) which is less than two. Hence RE170 is considered as a viable option to replace for the refrigerants with high global warming potential (GWP) like HCFCs and HFCs. RE170 can be used as blend component with other ecofriendly refrigerant. The main objective of the present study is to compute the thermodynamic properties of RE170 by using Martin Hou equation of state. Thermodynamic properties are useful to do the thermodynamic analysis of vapour compression refrigeration cycle. The properties computed are saturation vapour pressure, liquid density, specific volume, enthalpy and entropy (both in the saturated liquid and vapour state). In the present study a MATLAB code is developed to compute the above considered thermodynamic properties from the temperature about 133K-363K and pressure up to 27.2 bar. The computed properties of dimethylether is compared with NIST REFPROP database. Since thermodynamic properties of RE170 is not available in ASHRAE hand book and also in literature. Therefore NIST REFRPROP can be considered as reliable source as that of ASHRAE. The results shows that deviation of liquid and vapour phase enthalpy from that of NIST is -0.058 to 2.55%. Similarly deviation of liquid and vapour phase entropy from that of NIST is -0.037 to 1.88%. Deviation of specific volume and liquid density from that NIST is 0.10 to -2.54% and -0.42 to 0.008% respectively. Variation of saturation pressure is less than -0.65%. Overall the computed thermodynamic properties of RE170 by using Martin-Hou equation of state shows good agreement with NIST for the temperature range (133K-363K) and pressure up to 27.2 bar.