Refrigeration Science and Technology" proceedings series (original) (raw)
Related papers
Investigation of the Thermophysical Properties of the R744 + R1234YF Binary System
2017
In 2014, European F-gas directive plans the prohibition of fluorinated working fluids with GWP of 2500 or more from 2020. Consequently, new working fluids have to be considered in the future such as HydroFluoroOlefin, carbon dioxide or mixture of HFO with hydro-fluoro-carbon or CO 2. The knowledge of the thermo-physical properties of working fluid is essential for the evaluation of performance of heat pumps, ORC and refrigeration. Herein, several " French " laboratories proposed to investigate the thermo-physical properties of the R744 + R1234yf binary system. In 2014, Juntarachat et al. measured and correlated vapour liquid equilibria including mixture critical point. New experimental determinations for density and viscosity using vibrating densitometer and capillary viscometer are presented. Also, enthalpies of mixing are determined using BT-215 Calvet calorimeters. In addition, molecular simulation based on empirical force have been realized. Several thermodynamic and t...
Thermodynamic Performance Analysis of Hydrofluoroo
Global warming is one of most severe environmental concerns that our planet is facing today. One of its causes is the previous generation of refrigerants that, upon release, remain in the atmosphere for longer periods and contribute towards global warming. This issue could potentially be solved by replacing the previous generation's high global warming potential (GWP) refrigerants with environmentally friendly refrigerants. This scenario requires an analysis of new refrigerants for a comparison of the thermodynamic properties of the previously used refrigerants. In the present research, a numerical study was conducted to analyze the thermodynamic performance of specifically low GWP hydrofluoroolefens (HFO) refrigerants for an actual vapor compression refrigeration cycle (VCRC) with a constant degree of 3 K superheat. The output parameters included the refrigeration effect, compressor work input, the coefficient of performance (COP), and the volumetric refrigeration capacity (VRC), all of which were calculated by varying the condenser pressure from 6 to 12 bars and vapor pressure from 0.7 to 1.9 bars. Results showed that R1234ze(Z) clearly possessed the desired thermodynamic performance. The drop in refrigeration effect for R1234ze(Z) was merely 14.6% less than that of R134a at a 12 bar condenser pressure; this was minimum drop among candidate refrigerants. The drop in the COP was the minimum for R1234ze(Z)-5.1% less than that of R134a at a 9 bar condenser pressure and 4.7% less than that of R134a at a 1.9 bar evaporator pressure, whereas the COP values of the other refrigerants dropped more drastically at higher condenser pressures. R1234ze(Z) possessed favorable thermodynamic characteristics, with a GWP of 7, and it can serve as an alternative refrigerant for refrigeration systems for a sustainable environment.
Density of the Refrigerant Fluids of R365mfc and R152a: Measurement and Prediction
2016
This work presents the density of new environmentally friendly refrigerants 1,1-difluoroethane (R152a) and 1,1,1,3,3-Pentafluorbutane (R365mfc) in their pure fluid form as well as a mixture. The density is covered in the temperature range of -10C to 45C and the pressure range of p=0.65-10.47 bar. The density is measured by a vibrating-tube densitometer (DMA-HPM) manufactured by Anton Paar. The apparatus supplies data in the temperature range of -10°C to 200 °C and a pressure range of 0 to 1400 bar, with an uncertainty of 0.1%. The experimental data is validated using the ‘Volume Translated Peng Robinson Equation of State’ and high precision fundamental equations of state by Outcalt and McLinden from the National Institute of Standard and Technology (NIST). Outcalt and McLinden model achieve deviations less than 0.56% for R365mfc and 0.51% for R152a. The deviations of VTPR are within 2.5% and 15% for the pure fluid and the mixture respectively. .
International Journal of Refrigeration, 1993
A software package for both the computation of thermodynamic properties and the analysis of the usual vapour compression plant schemes is a useful tool for air conditioning and refrigeration researchers and manufacturers. At present, it could make an important contribution to the search for CFC substitutes; in fact, comparisons between two or more working fluids could be accomplished more easily. A program code carried out by the authors is presented by means of some demonstrative diagrams referring to a comparison between the 'ozone killer' R 12 and its substitute R 134a. An R134a exergy-enthalpy chart is also provided. Comparaison exerg6tique et thermodynamique du R12 et du R 134a utilis6s comme fluides actifs duns les machines frigorifiques 5, compression de vapeur Un logiciel pour le calcul des propriktbs thermodynamiques et l'analyse des installations classiques it compression de vapeur est un outil utile pour les ehercheurs et fabricants d'~quipements de conditionnement d'air et de froid. Actuellement, on pourrait utiliser cut outil informatique pour contribuer it la recherche de nouveaux substituts; en effet, il permettrait d'effeetuer plus facilement des comparaisons entre deux ou plusieurs fluides aetifs. On prbsente un code de programme, mis au point par les auteurs gr&ce h des diagrammes explicites bas~s sur des comparaisons entre le frigorig~ne R12 qui dbtruit la couche d'ozone et le R134a son substitut. On fournit bgalement un diagramme exergie-enthalpie pour le R134a.
Thermodynamic Properties of Potential Alternative Refrigerant HFO-1234ze(Z)
JST: Engineering and Technology for Sustainable Development, 2022
Cis-1,3,3,3-Tetrafluoropropene HFO-1234ze(Z) is an environmentally friendly potential alternative refrigerant for heat-pump application. In usability evaluation of this refrigerant in heat pump application, the accurate thermodynamic properties of HFO-1234ze(Z) in both single-phase and two-phase regions are needed. So, this paper aims to provide an accurate lgP-h diagram and the thermodynamic properties in both single-phase and two-phase regions. The accuracy of this published data and the lgP-h diagram was evaluated by comparing this data with available experimental data. The study shows that the average absolute deviations between our values and experimental data for vapour pressure, saturated liquid density, subcooled liquid density and gaseous pressure are 0,34%, 0,42%, 0,60%, and 0,99%, respectively. Additional evaluations for the ideal gas heat capacities and speed of sound are available in this work. The average absolute deviations between calculated values and published data...
2002
This project has measured data and developed models for the properties of R410A and other HFC blends. An emphasis was placed on conditions near and above the mixture critical point-conditions where existing data were scarce and where a serious degradation in the performance of airconditioning equipment has been observed. Many of the HFC blends have much lower critical temperatures than the CFCs or HCFCs (primarily R22) they are replacing, meaning that the operating temperatures of equipment using the blends can approach the critical temperature in extreme ambient conditions. In this project the isochoric (constant volume) heat capacity of R125 was measured and a comprehensive, high-accuracy equation of state for the thermodynamic properties of this fluid was developed. R125 is a component of several important HFC blends, and improvements to the pure fluid formulation were a precursor to an improved mixture model. The isochoric heat capacity and pressure-density-temperature (P-ρ-T) behavior of R410A were measured and these data, along with data from the literature, were used to develop a new equation of state applicable to the entire class of HFC blends. Finally, measurements of the viscosity and thermal conductivity of R410A and R507A were carried out and the resulting data were compared to the mixture model in the NIST REFPROP database. R507A is the blend R125/143a (50/50); it is a replacement for R502. The R125/143a binary pair also comprises the majority of R404A, which is the blend R125/143a/134a (44/52/4). In support of the R125 equation of state development, the isochoric heat capacity of R125 was measured over the temperature range 305-397 K (32-124 ˚C) at pressures up to 20 MPa. The measurements overlapped with existing data at lower temperatures and extended well above the R125 critical point of 339 K. These data are presented. A new formulation is presented for the thermodynamic properties of R125 based on both literature data and the new data measured in this project. This equation of state formulation is explicit in the Helmholtz energy and can be used for the calculation of all the thermodynamic properties, including density, heat capacity, speed of sound, enthalpy, entropy, and saturation properties. Ancillary equations are given for the ideal gas heat capacity, the vapor pressure, and for the saturated liquid and vapor densities. To minimize the number of terms, the equation was developed using new non-linear fitting techniques. Comparisons to the experimental data are given to establish the accuracy of properties calculated using the equation of state. The equation of state generally represents the experimental data within their uncertainties. The estimated uncertainties of calculated values are 0.1 % in density, 0.5 % in heat capacity, 0.02 % in speed of sound for the vapor at pressures less than 1 MPa, 0.5 % in the speed of sound elsewhere, and 0.1 % in vapor pressure. Deviations are higher in the critical region. The equation is valid for temperatures from the triple point temperature (172.52 K,-100.63 ˚C) to 500 K (227 ˚C) and pressures up to 60 MPa. Measurements of the P-ρ-T behavior of R410A were completed along 14 isochores (lines of constant density) and covered the temperature range of 200-400 K (-73 to 127 ˚C) with pressures to 35 MPa. The isochoric heat capacity was measured along eight isochores with temperatures ranging from 303 to 397 K (30 to 124 ˚C) with pressures up to 18 MPa. These calorimetric measurements also provided simultaneous data of the P-ρ-T behavior. These data are presented. Mixture models explicit in Helmholtz energy have been developed to calculate the thermodynamic properties of HFC refrigerant mixtures containing R32, R125, R134a, R143a, and/or R152a. The Helmholtz energy of the mixture is the sum of the ideal gas contribution, the compressibility (or real gas) contribution, and the contribution from mixing. The independent
International Journal of Thermophysics, 2000
Isothermal vapor–liquid equilibria (VLE) for the binary systems of difluoromethane (HFC-32)+1,1,1,2,3,3-hexafluoropropane (HFC-236ea) and pentafluoroethane (HFC-125)+1,1,1,2,3,3-hexafluoropropane (HFC-236ea) were measured at 288.6, 303.2, and 318.2 K using an apparatus in which the vapor phase was recirculated through the liquid. The phase composition at equilibrium was measured by gas chromatography, based on calibration using gravimetrically prepared mixtures. Both systems show a slight deviation
Calculation of thermodynamic properties and vapor-liquid equilibria of refrigerants
Chemical Engineering Science, 1978
A?Mract-Saturated state thermodynaimc propeNes of ref~rants are prcdrctcd from cnt~cal coordmates and normaI bodmg pomts by usmg Soave's equabon of state Bmary vapor-hquni cqtuhbna are correlated by determmmg mteraction parameters for the followmg SEX systems CC12FJCH3CHF2. CCIJ;JCHCIF~, CHF&X3F3, CClF&Xl~F, CCIZFJCCIS, CFXHS On the whole the method gves rehable results over broad temperature and pressure ranges for pracbcal engmeermg uses IN'WODUCI'ION Temperature Pressure References points range W) range (atm) klz UP (atm) uY CC12FJCH1CHF-Refrtgerant 500
Science and Technology of Environmental Protection, 2002
Vapor-liquid equilibrium, thermodynamic and volumetric properties were predicted for three pure hydrofluorocarbons (R32, R125 and R134a) as well as for binary mixtures of these refrigerants. Three cubic equations of state GEOS3C, SRK (Soave-Redlich-Kwong) and PR (Peng-Robinson) were used. A wide comparison with literature experimental data was made. For the binary refrigerant mixtures, classical van der Waals mixing rules without interaction parameters were used. The GEOS3C equation, with three parameters estimated by matching several points on the saturation curve (vapor pressure and corresponding liquid volumes), compares favorably to other equations in literature, resting simple enough for applications.
Screening of pure fluids as alternative refrigerants
International Journal of Refrigeration, 2006
Hydrofluorocarbons are now well established as refrigerants because of their zero ozone depletion potential. Since they have a high global warming potential, other alternatives as, e.g. fluorinated ethers or cyclic hydrocarbons are considered as nextgeneration refrigerants. Screening of alternative refrigerants is difficult because mostly no or only few data are available. To evaluate, e.g. the cycle performance, the thermodynamic properties of the refrigerants must be known and described accurately by an equation of state. Here, the physically based BACKONE equations are used to describe alternative refrigerants, such as natural refrigerants, hydrofluorocarbons, fluorinated cyclic hydrocarbons, and fluorinated ethers. BACKONE needs only a few substance specific parameters to describe thermodynamic properties with high accuracy. Thus, even alternative refrigerants, with very few available experimental data can be described. Calculations with BACKONE of the performance of many refrigerants show that some hydrocarbons and fluorinated ethers are a good alternative.