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Rochester Institute of Technology RIT Scholar Works Articles 1975 Predicting the properties of mixtures of R22 and R12 part I - Thermodynamic properties Satish Kandlikar C. Bijlani S. Sukhatme Follow this and additional works at: http://scholarworks.rit.edu/article Recommended Citation Kandlikar, Satish; Bijlani, C.; and Sukhatme, S., "Predicting the properties of mixtures of R22 and R12 part I - Thermodynamic properties" (1975). American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE),Accessed from http://scholarworks.rit.edu/article/1060 This Article is brought to you for free and open access by RIT Scholar Works. It has been accepted for inclusion in Articles by an authorized administrator of RIT Scholar Works. For more information, please contact [email protected]. NO. 2343 I I PREDICTING THE PROPERTIES OF NIXTURES Of R22 AND R12 PART I - THERMODYNAMIb PROPER 1DES , 1 ,, . S. G. KANDLIKAR C. A.131.1LANI Student Member ASHRAM Astatine Member S. P. SUKMATME - I Although the advantages of Using mixture refrigerants are well known, they have not often been used. One reason for this is the nonavailability of reliable , and readily useable information on their thermodynamic and transport properties. Even the properties of the azeotropic, mixture R501 (75 percent R22 and 25 per-' cent R12 by weight) are not-yet well established. The purpose of this study is to compile and complement previous work on the R22/R12 system and to present in one place reasonably reliable predictive , methods and tabulated values for determining the properties of mixtures of R22' and R12 of any concentration. This study is divided into two parts: Part I deals with thermodynamic properties and Part II with transport properties. Those thermodynamic proper-1 ties are as follows: 7 7 - ; 1. Equilibrium pressure and temperature 2. Equilibrium liquid and vapor phase compositions 3 . b e all y of saturated liquid '4. Specific volume of saturated vapor 5. Enthalpy of saturated liquid 6. Enthalpy of saturated vapor 7. Specific heat of liquid at saturation 8. Specific heat of vapor at saturation 9. Entropy of saturated liquid 10. Entropy of saturated vapor. -- PREVIOUS WORK Bijlani (1 and 2) has developed procedures for the prediction of some thermoi dynamic properties of the system R22/R12, and Quraishi (3) has recommended an equation of state for the azeotropic mixture R501. Experimental phase equilibrium data are reported by Loeffler (4), but the recent data by Kriebel (5) seems to be more accurate since it was checked for thermodynamic consistency. The heat of mixing and the latent heat of vaporization have been measured at-60.07F i by Neilson and White (6). DATA ON INDIVIDUAL REFRIGERANTS To predict mixture properties, data on individual refrigerants are required. These are taken from Ref. 5, 7,8 and 9. Whenever the data are available in the form of equations, they are directly used. In the case of tabulated data, suitable equations are fitted over the desired temperature range. Equation of State Bijlani (1) has shown that the short Martin-Hou equation can represent the P-V-T data with great accuracy. This equation with all its terms has the form: S.G. Kandliker, C.A. Bijlani, and S.P. dukhatme, Department of Mechanical 'Engineering, Indian Institute of Technology, Powai, Bombay 400076 The values of the constants for A22 and R12 as obtained by Bijlani (1) are as follows: Constant R22 R12 -- A2 -5.108894E+0 -3.714446E+0 82 3.202996E-3 2.229788E-3 C2 -3.641094E+1 -2.819800E+1 A3 1.495317E-1 7.089601E-2 83 -1.243149E-4 -4.475688E-5 A4 -3.058400E-3 -7.375492E-4 84 3.200155E-6 5.622223E-7 C4 3.043126E-2 1.467384E-2 b 3.128E-3 3.458E-3 k -4.2 -5.0 Saturated Liquid Density The correlations for saturated liquid density are taken from Ref '7 for R22 and from Ref 8 for P12. Saturated Liquid Enthalpy The saturated liquid enthalpy values for R22 ri ot for P12 arc taken from Ref 9 and arts fitted by the least squares method es eleventh and eighth order polynomial functions respectively of (1 419.67) over the temperature range 360 to 660 R. The average absolute deviations are less than 0.03 percent for R22 and 0.01 percent for R12. Thus: H = E 11(I).(T -419.67) 1=1 n = 11 for R22 (2) n = 8 for 812 in which the constants H(I) become: Constant 822 R12 H(1) 2.5284399E-1 2.1058947L-1 H(2) 1.8028825E-4 5.4887343E-5 H(3) 3.4259758E-7 1.5382998E-7 11(4) -3.5256820E-9 - 3.6692264E-10 8(5) -1.2304273E-10 - 3.3681939E-12 2.1294720E-12 1.3294897E-13 H(6) 8.0806707E-15 - 7.2100676E-16 H(8) -3.7145822E-16 1.3565186E-18 H(7) H(9) 2.9867823E-18 H(10) -1.0118069E-20 H(11) 1.2818978E-23 . Saturated Liquid Specific Heat ; In a similar manner, the satUrated liquid specific heat values at constant preSsure for R22 and for R12 are taken from Ref 9 and are fitted by the least squares method as a fourth order polynomial function of absolute temperature over the range of 360 to 660 R. The calculated values agree with the original' values to•the last-digit. Thus: ' C Pi 5 E 11. C(1) p(' -1) in which the constants C(i) become: R22 Constant R12 2.7861431E+0 '2.2021156E+0 C(2) -2.2971282E-2 -1.8404225E-2 C(1) C(3) 7.7565845E-5 . C(4) -1.1608676E-7 C(5) 6.5654243E-41 6.2756385E-5 -9.4173491E-8 5.2904772S-11 Ids ai ras H at Ca acit The correlations for the ideal gas heat capacity at constant volume are 8 for R12. taken from Ref 7 for R22 and from Ref EVALUATION OF MIXTURE PROPERTIES Equation of State The Martin Hoe Equation (1q (1)) is also used to represent the P -V -T relationship for mixtures. The constants of this equation are obtained by suitably combining the constants for individual refrigerants. The combining rules, suggested by Dijlani (1) and later modified by Quraishi (3) to agree with the azeotropic mixtures R502 and R503, are believed to be valid for the binary system R22/R12 and are used. These combining rules are Constant A2: . (A2)m • 1 , 2 -0.1X1 X (4a) x1(A2)1 /2 + x (A )-2/2 2 2 2 Constant 132 : (B2) , x (B2)1 m' 1( 13 2)1 + 2 . Constant C2: (4b) Equilibrium Pressure and Temperature . Mixtures of refrigerants boil through a range of temperature at a given pressure. Similarly the bubble point and dew point pressures for a given temperature and concentration are different. These are obtained from the respective bubble point and de* point curves. For pure refrigerants, these two curves can be represented by a single equation. Vapor pressure data of pure refrigerants is well represented by Antoine's `Equition: lb(P) = A + (5) Bijlani (2) has used the same equation for representing the bubble point curve for the system R22/R12 with the help of Loeffler's data The same procedure will be followed, and the equilibrium data of pressure, temperature and concentration given by Kriebel in the temperature range 380 to 600 R will be used to obtain the bubble point and dew point curves in the form of Eq (5). Bubble Point Curves ln (Pts) A BBL + BB2 B (6) in (PD) '2 0" T-CD (7) Dew Point Curvet DD2 the constants BB1, BB2, DD1, and DD2 are considered to be polynomial functions of concentration: 6 BB1 = E Bl(I) Y ( I -1) (8a) I=1 BB2 A 6 Iii I =1 y(/-1) . DD1 6 E Dl(I) YV(I -1 ) I=1 DD2 6t D2(I) YV (I-1) /A1 (8b) (9a) (9b) The constants CB and CD take values between 25 and 50 for pure refrigerants. So, for mixtures over the entire range of concentration, this value is varied in steps of unity, and the 24 constants in Eq (8) and (9) are evaluated by the . least squares method. Then values of presaures calculated from &I - (6) and (7) are compared with the original data and those values of CB and CD, which give best agreement with the data over the entire range, are selected. It was found that for the value CB - CD = 35, the average absolute deviations from the original data were minimum (0.421 percent for D.P. curve and ,0.527 percent for D.P. curve), With these values of CB and CD, the other con'stants are found to have the following Values: B1(1) = 1.22095352E+1 D1(1) = 1.22097208E+1 81(2) = -1.22882463E+0 D1(2) = -5.28703810E-1 B1(3) = 6,21189084E+0' D1(3) = ,6.90830461E+0 • - B1(4) = -1.01467610E+1, : - - D1(4) = -1.99669780E+1-- B1(5) = 6.91461772E+0 Dl(5) = 2.19836792E+1 B1(6) = -1.36151186E+0 D1(6) = -8:00690212E+0 82(1) = -3.84123014E+3 D2(1) = -3.84131226E+3 B 2 ( 2 ) = 1.11635983E+3 D2(2) = 4.45378468E+2 82(3) = -3.46853800E+3 ' 02(3) - -3.17706719E+3, 82(4) = 5.18083844E+3 D2(4) = 1.01448365E+4 82(5) = -3.46692800E+3 D2(5) = -1.17573616E+4 B2(6) = 6.79394878E+2 D2(6) = 4,38535765E+3 and • • A Equilibrium Vapor Phase Con:Position The equilibrium vapor phase composition can he calculated by methods based on thermodynamic considerations (e.g, Barker's (11) Method). HOwever, the procedure is usually quite cumbersome, and because Kriebel's experimental results are available, a very simple method is deVeloped here. For any given liquid mole fraction Of R22 and any given temperature, the bubble point pressure is calculated from Eq (6). Using this pressure as the dew point pressure and with the given temperature, the equilibrium vapor phase ;composition is obtained from Eq (7). This calculation is done by the Newton'Raphson Iterative Technique_ and presents no difficulties determining liquid :mole fractions up to 0.1 of R22. Above this value (particularly at low temper-, atures), two problems arise as illustrated in Fig. 1. Firstly, corresponding to a given pressUre and temperature, there are apparently two vapor phase compositions (points B and C). Secondly, the equilibrium vapor phase composi'tion often lies close to the minimum of the T,- YV curve, thus making the Newton-Raphson Technique unsuitable. The first difficulty is resolved by recognizing that the equilibrium vapor Phase composition and the given liquid. ,mole fraction must lie on the same side of the minimum value. Thus 'at these compositions, the corresponding slölies of the T Y and T- YV cures should have the same sign. In order to overcome the second difficulty, a search :technique is used instead of the Newton-Raphson Technique. The temperature is ; calculated froM Eq (7) by varying the concentration in steps of 0.0005. The 'concentration yielding a temperature which agrees within 0.005 F of the given 'value is taken to be the eqUilibrium vapor phase comPosition. I Density of Saturated Liquid Mixture ! . , .., . The volume of mixing fOi* the binary liquid system R22/R12 as measured by Loeffler (4) is very small, and neglecting it does not introduce an error !.greater than 1.5 percent. Rlso the effect of small changes in pressure on liquid density is negligibld. Thus, the saturated 3,ieni4 refriferent volume* I at the system temPerature are additive, and the density of the saturated liquid mixture is given by, Specific Volume-of Saturated Vapor Mixture Eq (1) is used to find the volume of the:saturated vapor. The. NeWt0P .Raphson ;terative:Zechnique.4.0 OMEaoyekfOr_this,purpose,„ . Enthalpy of Saturated Liquid Mixture The enthalpy of the liquid mixture is given by: (where: H m i x is the enthalpy of mixing. The enthalpy of mixing has been CalCulated by Bijlani (2) by step integrating Margule's Equation and adusting the constants to fit the data of 'Neilson and White (6). These equations are as follows: I Enthalpy of Saturated Vapor Mixture The variation of enthalpy of vapor with pressure and temperature is given bvs Substituting: Substituting for P and fiksiv from Eq (1) and integrating Eq (20) between a reference temperature and zero pressure to any given temperature T, pramsura P 'and voLume Vs where: AEI, 8E1 ... are the conLtants in the individual refrigerant ideal gas heat capacity correlations. , XX depends on the reference state. /n the present case, the enthalpy of saturated pure liquid refrigerant at -40 F is taken to be zero. To reduce any errors in the Eq (23), the enthalpy values are corrected at -60.07 F to agree with the latent heat of vaporization data of Neilson and White (6). Thus: where AL are the latent heat values in Dtuilb mole of Neilson and White. These values are fitted by the least squares method as a fifth order polynomial function of the mole fraction of R22. Thugs The constants A(I) become: A(1) - 5.8298967E+3 A(2) 1.1 -3.8326504E+2 A(3) m -6.9372150E+2 A(4) • -5 1693059E+2 A(5) . 9.9005677E+2 A(6) .., 5.0924091E+2 Specific Heat of Liquid Mixture at Saturation Neglecting the effect of small changes in pressure and the variation of lA temperature and pressure, the specific heat of !the liquid mixture at saturation is given by: • .heat of Mixing with changes 'Specific Heat of Vapor Mixture at Saturation • Differentiating the expression for the enthalpy of saturated vapor mixture, Eq (23), with respect to temperature at constant pressure, determines the 'specific heat at constant pressure of the, vapor mixture at saturation. Thus: . Entropy of Saturated Liquid Mixture The entropy of the saturated liquid mixture is computed from the entropy of the saturated vapor mixture and the enthalpy of vaporization. Thus at a given pressure: ,where: Tav is the average of the dew point and bubble point temperatures, ;Entropy of Saturated Vapor Mixture The change in entropy is given by: YY depends on the reference state chosen. In this case also, the entropy of the saturated pure liquid refrigerant at -40 F is taken to be zero. However, for-the azeotropic mixture R501, the reference state for enthalpy and entropy is shifted to zero for saturated liquid mixture at -40 F. DATA EVALUATION With the help of methods developed above, the thermodynamic properties for mixtures of R22 and R12 are calculated in the temperature range of -100 to +200 F. A computer program (Ref 10) is developed for this purpose. FPS units are employed throeghout, since all the thermodynamic properties for pure refrigerants are available in these units. Tables 1-6 contains thermodynamic properties at concentrations of 0, 0.2, 0.4• - 0.6, 0.8, and'1.0 in the temperature range of -50 to +100 F in steps of 10 deg P. The concentrations of 0 and 1, corresponding to the pure refrigerants, are given so that interpolation can be readily done for any concentration. The same thermodynamic properties are given ih Table 7 for the azeotropic mixture R501.. More detailed tabulations over a larger range of temperature are given in Ref 10. It can be observed that the tabulated values for pure refrigerants R22 and R12 differ slightly from those given in Ref 9. This is because Kriebel's vapor pressure data is used in the entire range of concentration and because the modified equation of state is used for pure refrigerants. Accuracy of Prediction The equilibrium pressure and temperature relationship is accurate to within 1 percent. Saturated liquid density and specific heat values arc expected to be accurate within + 1 percent. Saturated vapor specific volume, enthalpy, specific heat and entropy; and saturated liquid entropy are all believed to be accurate within + 3 percent at temperatures well below critical. However, near critical temperatures, larger deviations are possible. NOMENCLATURE C specific heat at constant . pressure, Btu/lbm F C vspecific heat at constant volume, Btu/lb m F H specific enthalpY, Btu/lbm P pressure, lbein2 R gas constant - S specific entropy, Btu/lb mF T Temperature, R V specific volume, ft3/ib m W molecular weight, lb m/lbm mole X liquid weight fraction of R22 XV vapor weight fraction of R22 ly TV liquid mole fraction of R22 vapor Imola fraction of-R22 - Superscripts * ideal gas state Subscripts 1 1 R22 2 R12 c critical fg difference between vapor and liquid I, liquid m mixture ✓ vapor' - Greek symbols density , lnm/fti activity Coefficient REFERENCES "Pressure-Volume-Temperature Relationships of Binary 1. C.A. Bijlani, Mixtures of Refrigerants", Proceedings, 13th Int. Cong. of Refrigeration, Washington, 1971 • "Thermodynamic Properties and Refrigeration Characteristics 2. C.A. Bijlani, of Binary Mixtures of Freon 12 and Freon 22", Doctoral thesis, Indian Institute of Technology, Bombay, 1967 3. R.A. Quraishi, "Predicting the Pressure-Volume-Temperature Behaviour of Binary Mixtures of Fluorocarbon!, M.Tech. Dissertation, Indian Institute of Technology, Bombay, 1972 4. H.J. Loeffler, "Some Properties of the Binary System rreon -12 -Freon -22 and of Ternary System Freon -12 -Freon -22 -Napthetic Mineral-Oil", Annexe, I.I.R. 143, 1969-61 "Phase EquilibriUS Between Liquid and Vapor in the Binary 5. M. Kriebel, 1System of Difluoromonochloromsthane -DiflUorodichloromethane", Doctoral Dissertation, D83, Berlin, 1966 6. E.F. Neilson, and D. White, "Heat of Vaporization and Solution of a Binary Mixture of Fluorocarbons", J. Phys. Chem. 63, 1363-5, 1959 Thermodynamic Properties of Freon-22, E.I. Du Pont De Nemours and Co. (Inc), Wilmington, Delaware 8. Thermodynamic Properties of Freon-12 E.I. Du Pont de Nemours and Co. (Inc.), ` Wilmington, Delaware 9. ASHRAE HANDBOOK OF FUNDAMENTALS, 1972 10. S.G. Kandlikar, and S.P. Sukhatme "TherModynamic and Transport Properties of R22/R12 Mixtures", Report, Thermal Sciences Group, Mach. Engg. Dept. Indian Institute of Technology, Bombay, 1974 11. J.A. Barker, "Determination of Activity Coefficients from Total-Pressure Measurements", Australian J. Chem., 6, 2 7-10, 1953 ACKNOWLEDGEMENT These computations were performed on the CDC-3600 Computer system of the Tata institute of rundaMental Research, Bombay. TABLE 1 THERMODYNAMIC PROPERTIES OF BINARY MfXTURE R22-R12 Mole fraction of R22 = 0.0 (pure R12) Volume Temperature Pressure gu ft0, F psia Vapor -10 7.08 9.24 11.90 15.14 19.03 5.0189 3.9191 3.0981 2.4767 2-.0004. -50 -43 -33 -23 . Density 113/cu ft Liquid 95.62 94.66 93.69 92.70 . 91.69 Enthalpy* Btle40, EiquitrVapor Li4indvapor -2.101 0.000 2.112 4.235 6.371 71.809 72.945 74.078 75.206 76.326 0.210 0.212 0.213 0.215 0.216 0.128 0.130 0.133 0.135 0.138 -0.00507 0.00000 0.00496 0.00982 0.01459 0,17534 0.17382 77.436 78.534 79.617 80.684 81.731 0.218 0.219 0.221 0.222 0.224 0.140 0.143 0.146 0.149 0.152 0 23.67 10 20 30 40 29.15 35.56 43.00 51.57 1.6311 1.3415 1.1121 0.9288 0.7806 90.66 89.61 .68.51 87.43 86.33 8.520 10..684. 12.863 15.059 - 17.273 50 6370 61.38 . 72.54 85.14 99.30 115.13 0.6605 0.5618 0.4803 0.4126 0.3558 85.14 83.95 82.72 81.45 80.15 19.508 21.766 24.050 26.364 28.712 82.757 83.757 84.729 85.670 65.575 0.226 0.156 0.228 0.159 0.230 0.163 0.233 0.167 0:237 0.172 132.73 0.3080 78.79 31.100 87.441 0.241 80 90 100 Equilibrium Entropy* VapOr Btuflb R Liquid Vapor Composition** Specific heat BV3ilb F 0.177 . 0.17245 0 .0 0.0 . 0.0 0.17124 0.0 0.17016 0.0 0.01927 0.02367 0.02841 0.03287 0.03728' 0.16920 0.16834 0.16757 0.16689 0.18628' 0.0 0.0 0.0 0.0 0.0 0.04163 0.04594 0.05022 0.05446 0.05869 0.16573 0.16523 0.16476 0.16436 0.16396 0.0 0.0 0.0 0.0 0.0 0.06291 0.16358 0.0 *Based on 0 for the saturated pure liquid refrigerant at -40F **Expressed in mole fraction of R22 Note: The above values for pure refrigerants differ slightly from those given in Ref (9) because of the following reasons: (i) The vapor pressure data of Kriebel is used (ii) A modified equation of state is used, (iii) Some property values in Ref (9) are fitted by the least square method as functions of temperature. Temperature Pressure •sia volume • Vapor F Density Enthalpy* lb cu ft Bt lb Liquid Liquid Vapor Specific heat Btu lb F iqui• Vapor Equilibrium Entropy* Vapor Bim lb R 'qui. Vapor Composition** -50 -40 -30 -20 '-10 9.13 11.82 15.10 19.06 23.79 7.92 10.32 13.27 16.85 21.15 4.7498 3,7147 2.9406 2.3538 1.9034 94.55 93.59 i 92.61 91.61 90.59 -0.977 1.177 3.345 5.529 7.729 75.782 76.917 78.046 79.167 80.277 0.218 0.219 0.221 0.223 0.224 0.130 0.132 0.135 0.137 0.140 -0.00362 0.00165 0.00681 0.01187 0.01685 0.18616; 0.18441 0.18283 0.18141 0.18012 0.388 0.383 0.378 0.373 0.368 0 10 20 29.39 35.95 43.58 26.27 32,30 39.35 1.5536 1.2790 1.0613 89.55 88.49_ 87.41 9.946 12.180 14.432 81.375 82.488 83.523 0.226 0.227 0.229 0.143 0.146 0.149 0.02173 0.02655 0.03128 0.17896 0.177'91 0.17696 0.363 0.358 0.353 30 40 52.39 62.47* 47.52 56.93 0.8870 0.7463 ,86.29 85.15 16.705 18.998 84.568 85.590 0.231 0.233 0.1527 0.156 0.03596 0.17609 0.04057 0.17530 0.3418 0.343 . 50 60 70 80 90 73.95 86.94 101.53 117.85 136.00 67.68 79.89 93.67 109.14 126.41 0.6317 0.5376 0.4599 0.3951 0.3409 83.98 82.77 81.53 80.25 78.92 21.316 23.660 26.034 28.440 30.882 86.587 87.555 88.491 89.392 90.252 0.235 0.237 0.240 0.243 0.247 0.159 0.163 0.168 0.172 0.177 0.04514 0.17457 0.04966 0.17389 0.05414 0.17326 0.05860 0.17267 0.06303 0.17210 0.338 0.333 0.320 0.323 0.319 100 156.09 145.60 0.2952 77.54 33.366 91.069 0.252 0.183 0.06746 0.314 0.17154 Temperature IP • Pressure •sia :. Density Volume Enthalpy* t lb lb cu ft' Btu lb Vapor 144111•LIquid Vapor Specific heat Btu- ib F iqul•Vapor EntrOpy* Equilibrium Btu lb R Vapor Lqul• Vapor Composition** -5 0 -40 -30 -20 -10 10.49 13.56 17.30 21.82 27.20 9.23 11.99 15.38 19.49 24.41 4.3270 3.3910 2.6894 2.1564 1.7464 93.38 92.41 91.42 90.41 89.38' -0.312 1.935 4.202 6.488 8.796 80.534 81.661 82.77? 83.882 84.972 0.226 0.228 0.230 0.231 0.233 0.132 0.134 0.137 0.140 0.143 -0.00200 0.00349 0.00587 0.01417 0.0193? 0 10 20 30 33.56 41.00 49.65 30.25 37.12 45.13 1.4274 1.1765. 0.9772 88.34 87.26 86.1? 11.125 13.476 15.849 86.045 87.098 88.128 0.235 0.237 0.239 0.146 0.149 0.153 69.63 54.42. 71.64 - 65.06 0.8174 85.04 18.246 80.133 0.241 0.6881 83.89 20.670 90.109 40 50 60 70 80 90 84.01 98.67 115.14 133.53 153,97 77.22 91.00 106.53 123.94 143.35 0.5827 0.4961 0.4244 0.3647 0.3145 82.71 81.49 80.23 78.93 .77.58 23.122 25.605 28.121 30.673 33.265 . 91.053 100 176.58 164.87 - 0.2722 76.15 35.902 95,161 91.962 92.832 93.658 94.436 . 0.19766 0.19566 • 0.19384, 0.19218 0.19067 0.546 0.544 0.541 0.5390.537 0.02450 0.02955 0.03453 0.18928 0.18801 0.18683 0.534 0.532 0.530 0.156 0403945 0.18574 0.528 0.243 0.160 0.04431 0.18473 0.525 - 0.245 0.248 0.251 0.255 0.259 0.165 0.169 0.174 0.180 0.186 0.04913 0.18378 0.05390 0.18289 0.05864 0.18203 0.06335 -0.18121 0.06805 0.18041 0.523 0.521 0.518 0.516 0.514 0.264 0.193 0.072•2 0.511 0.17961 A Temperature F • . Density PreeeUre Volume -sia t lb lb cu f 0* Vapor iquid • ..........-------........ Enthalpy* Btu/lb Liquid Vapor Specific heat Btu lb P lqui. Vapor 11.45 14.80 18.89 23.8129.68 10.95 14.16 18.08 22.80 28.44 3.8838 3.0564 2.4334 1.9581 1.5911 92.08 91.10 90.10 89.08e 88.05 -0.230 2.128 4.512 6.921 9.357 0 10 20 30 40 36.61 44.73 54.16 65.03 77.46 35.11 42.93 52.01 62.4874.47 1.3044 1.0782 0.8978 0.7528 0.6351 86.99 85.91 84.80 83.67 82.50 91.205 11.819 14.308 • 92.222 93.211 16.825 94.168 19.370 21.947 95.091 50 60 70 80 90 91.60 107.57 125.51 145.55 167.81 88.11 103.53 120.85 140.21 161.73 0.5389 0.4596 0.3937 0.3387 0.2925 81.31 80.07 78.80 77.48 76.12 24.558 27.205 29.890 32.615 35.384 95.977 96.820 97.617 98.363 99.052 0.257 0.260 0.264 0.268 0.273 100 192.44 185.55 0.2533 74.69 38.203 99.679 0.278 -50 -40 -30 -20 -10 85.803 86.916 88.016 89.099 90.163 Entropy* EquilibriuM Btu b R Vapor Liqui Vapor Composition** 0.236 0.238 0.240 0.241 0.243 0.135 0.137 0.140 0.143 0.146 -0.00112e 0.00463 0.01029 0.01585 0.02134 0.20976 0.20752• 0.20546 0.20357 0.20183 0.245 0.247 0.250 0.252' 0.150 0.153 0.157 0.162 0.02674 0.03208 0.03735 0.04255 0.20021 0.19872 0.19732 0.19601 0.672 0.672 0.673 -0.673 0.28g 0.166 0.04771 0.19478- 0.673 0.171 0.176 0.182 0.189 0.196 0.05282 0.05789 0.06292 0.06793 0.07292 0.19361 0.19249 0.19142 0.19037 0.18933 0.674 0.674 0.674 0.674 0.675 0.204 0.07789 0.18830 0.675 1 0.671 0..671 9.6711 0.672; 0.672: Pressure Temperature nsia F B - DP Density Volume Enthalpy* cu ft/lb lb/cu ft Btu/lb vapor . Liquid Liquid vapor Specific heat Btu/lb F Liquid Vapor Equilibrium-. Entropy* Vapor Btu/lb R L,quid Vapor Coilpositiun** 3.8081 2.9973 2.3866 1.9206 1.5606 90.63 89.64 88.63 87,61 86.56 .4).692 1.56? 4.056 6.578 9.131 91.633 92.740 93.833 94.905 95.953- 0.247 0.249 0.251 0.253 0.137 0.140 0.143 0.146 0.150 -0.00227 0.00372 0.00961 0.01543 0.02117 0.22360 0.22100 0.21860 0.21638 0.21431 0.807 0.812 0.816 1.819 0.821 38.32 46.84 56.73 68.13 81.18 1.2793 1.0573 0.8803 0.7379 0.6223 85.49 84.40 83.29 82.14 80.9? 11.717 14.335 16.985 19.669 22.390 96.975 97.96? 98.925 99.846 100.727 0.257 0.260 0..262 0.265 0.267 0.153 0.157 0.162 0.166 0.171 0.02683 0.03243 0,03797 0.04344 0.04887 0.21239 0.21059 0.20889 0.20729, 0.20576 0.822 0.823 0.824 0.825 ' 0.826 96.65 113.58 132.60 153.86 177.59 96,02 112.79 131.63 152.68 79.76 78.51 77.22 75.89 25.150 27.982 30.796 33.686 101.563 102.350 103.083 103.757 0.271 0.274 0.278 0.283 0.177 0.183 0.189 0.197 0.05426 0.05961 0.06492 0.07021 0.20430 0.20290 0.20153 0.20019 0.825 0.827 0.827 0.827 176.37 0.5278 0.4499 0.3852 0.3311 0.2857 74.50 36.622, 104.364 0.288 0.205 0.07546 0.1906 0.82? 203.6? 201.95 0.2472 73.05 39.612 104.899 0.295 0.215 0.08074 0.19753 0.828 -50 -40 -30 -20 -10 11.98 15.50 19.83 24.98 31.16 11.97 15.48 19.75 24.91 31.06 0 10 20 30 40 38.48 47.05 57.02 68,51 81.6? 53 60 70 80 90 100 - TABLE 6 THERMODYNAMIC PROPERTIES OP BINARY MIXTURE R22-R12 Mole fraction of R22 1.0 (pure R22) Temperature F Pressure s ip Volume Density Vapor Liquid _ -50 -40 -30 - 11.66 15.18 19.50 4.2302 3.3080 2.6178 89.00 -20 -10 24.74 2.0943 31.02 0 10 20 Enthalpy* L qui Vapor 0.140 -0.142 0.145 0.149. 0.152 -0.00605 0.00000 0.00598 0.01189 0.01774 0.24142 0.23827 0.23535 0.23263 0.23008 1.000 1.000 1,000 0.156 0.160 0.165 0.169 0.175 0.02353 0.02926 0.03493 0.04055 0.04614 0.22769 0.22544 0.22330 0.22127 0.21933 1.000 .1.000 1.000 107.956 0 271 0.274 0.276 0.279 0.283 108.760 109.506 110.189 110.800 111.333 '0.181 0.286 0.187 0.290 0.295, 0.194 0.202 0.300 0.212 0.307 0.05169 0.057210.06271 0.06818 0.21746 0.21564 0.21387 0.21212 1,030 27.173 30.121 33.117 36.164 1.000 1.07 1.000 0.07364 0.21039 1.000 39.267 111.778 0.314 0.07909 0.20665 1.000 86.99 98.870 99.996 1C1.101 1.6923 85.96 84.90 5.131 7.753 102.183 103.236 38.50 47.30 57.57 1.3799 1.1346 0.9400 83.82 82.72 81.60 10.411 13.105 15.836 134.259 105.246 106.194 30 40 69.48 83.17 0.7842 0.6583 80.44 79.25 18.606 107.099 21.417 50 98.81 '0.5558 78.03 24.272 60 70 80 90 116.55, 136.57 159.03 184.08 0.4717 0.4021 0.3442 0.2956 76.77 75.47 74.12 72.71 100 211.90 0.2546 71.23 aqua Entropy* EquilibriuM Btu/lb R Vapor Liquid Vapor Composition** 0.260 0.262 0.264 0.266 0.269 -2.511 0.000 2.547 88.01 Specific heat Btu _lb F Vapor 0.222 *Based on 0 for the saturated pUre liquid refrigerant at -40F **Expressed in mole fraction of R22 Note: The above values for pure refrigerants differ slightly from those given in Ref (9) because of the following reasons: (i) The vapor pressure data of Kriebel is used (ii) A modified equation of state is used, (iii) Some property values in Ref (9) are fitted by the least square method as functions of temperature. 1.000 1.000 1.000 .1.000 Temperature F Pressure m 'a • Volumeft b Vapor Density Enthalpy* lb cu ft' B lb Liquid Liquid Vapor Specific heat Btu lb F iqui• Vapor . - EquilibriuM Entropy* Btu lb R Vapor iglu. apor Composition** -50 -40 -30 -20 -10 11.99 15.51 19.81 25.00 31.19 11.98 15.49 19.77 24.94 31.10 3.8156 3.002E 2.3907 1.9236 1.5628 90.57 89.58 88.5? 87.55 86.50 -2.462 0.000 2.493 5.018 7.575 90.339' 91.460 92.542 93.615 94.663 0.248 0.250 0.251 0.254 0.256 0 10 20 30 40 38.52 47.11 57.09 68.60 81.78 38.38 46.91 56.82 68.25 81.34 1.2810 1 0586 0.0612 0.7386 0.6229 85.44 84.34 83.23 82.08 80.91 10.165 12.787 15.441. 18.130 20.855 95.684 96.675 98.553 99.433 0.258 0.154 0.260 0.158 0.262_ 0.162. 0.265 0.166 0.268 '0.171 0.02313 0.20925 0.02874 0.20743 0.03428 0.20572 G.03977. 0.20410 0.04520 0.20257 0.829 0.830 0.8311 0.832 0.832 50 60 70 80 90 96.78 113.74 132.80 154.11 177.80. 96.21 113.02 131.91 '153.02 176.48 0.5282 0.4502 0.3854 0.3313 0.2858 79.70 78.45 77.16 75.82 74.43 23.620 26.427 29.277 32.172 35.114 100.268 101.053 101.784 102.454 103.059 0.271 0.275 0.279 0.284 0.289 0.177 0.183' 0.190 0.197 0.206 • 0.05060 0.20109 0.05596 0.19967 0.06128 0.19829 0.06658 '0.19694 0.07186 0.19560 0.832 0.833 0.833 0.833 0.83Z 100 204.02 202.43 0.2472 • 72.98 38,109 103.590 0.295 0.215 0.07713 0.834 0.137 0.140 0.143 0.146 0.150 -0.00600 0.00000 0.00589 0.01171 0.01746 - " 0.22054 0.21792 0.21551 0.21327 0.21119 0.19426 0.813 0.819 ' 0.823 0.826 0.828 MOLE FRACTION OF R 22 - Fig. 1 Temperature concentration diagram for binary system R22/R12