COMPRESSIBILITIES 2-143

INTRODUCTION

The compressibility factor Z can be calculated by using the definingequation Z = PV/(RT), where P is pressure, V is molar volume, R isthe gas constant, and T is absolute temperature. Values of P, V, andT for substances listed in Table 2-184 are given in tables in theThermodynamic Properties section. For the units used in thesetables, R is 0.008314472 MPa·dm3/(mol·K). Values at temperaturesand pressures other than those in the tables can be generated formany of the substances in Table 2-184 by going to http://webbook.nist.gov and selecting NIST Chemistry WebBook, then Thermo-

physical Properties of Fluid Systems High Accuracy Data. Resultscan be pasted into a spreadsheet to facilitate calculation of the com-pressibility factor.

UNITS CONVERSIONS

For this subsection, the following units conversions are applicable:°R = 9⁄5 K

To convert bars to pounds-force per cubic inch, multiply by 14.504.To convert bars to kilopascals, multiply by 1 × 102.

COMPRESSIBILITIES

TABLE 2-142 Composition of Selected Refrigerant Mixtures

Composition (mass percent)

Mixture Tables R-32 R-125 R-134a R-143a

R-410A 2-290 50 50R-404A 2-288 44 4 52R-507A 2-296 50 50R-407C (Klea 66) 2-263, 2-264, 2-289 23 25 52R-407A (Klea 60) 2-143, 2-261 20 40 40R-407B (Klea 61) 2-144, 2-262 10 70 20

TABLE 2-143 Compressibility Factors for R 407A (Klea 60)

Pressure, bar

T, K 1 5 10 15 20 25 30 Zdew Pdew

250 0.9691 0.0163 0.0325 0.0487 0.0648 0.0809 0.0970 0.9340 2.05260 0.9737 0.0161 0.0321 0.0480 0.0640 0.0798 0.0957 0.9136 3.08270 0.9773 0.4268 0.0318 0.0476 0.0633 0.0790 0.0947 0.8895 4.46280 0.9803 0.8932 0.0316 0.0473 0.0630 0.0785 0.0940 0.8614 6.28290 0.9828 0.9080 0.0360 0.0473 0.0629 0.0784 0.0938 0.8290 8.60300 0.9848 0.9199 0.8253 0.0476 0.0632 0.0787 0.0942 0.7916 11.53310 0.9866 0.9298 0.8495 0.7518 0.0641 0.0797 0.0952 0.7485 15.15320 0.9881 0.9380 0.8689 0.7889 0.5737 0.0816 0.0972 0.6983 19.58330 0.9893 0.9449 0.8847 0.8173 0.7386 0.6279 0.1011 0.6386 24.96340 0.9904 0.9509 0.8980 0.8401 0.7752 0.6993 0.6016 0.5641 31.46350 0.9914 0.9560 0.9092 0.8588 0.8038 0.7425 0.6713 0.4564 39.42

Zdew 0.9593 0.8809 0.8107 0.7502 0.6936 0.6381 0.5813Tdew, K 234.3 273.3 295.1 309.6 320.9 330.1 337.9

The values in this table were generated from the NIST REFPROP software (Lemmon, E. W., McLinden, M. O., and Huber, M. L., NIST Standard Reference Data-base 23: Reference Fluid Thermodynamic and Transport Properties-REFPROP, National Institute of Standards and Technology, Standard Reference Data Program,Gaithersburg, Md., 2002, Version 7.1).

TABLE 2-144 Compressibility Factors for R 407B (Klea 61)

Pressure, bar

T, K 1 5 10 15 20 25 30 Zdew Pdew

250 0.9703 0.0180 0.0359 0.0538 0.0716 0.0894 0.1071 0.9251 2.40260 0.9745 0.0178 0.0355 0.0532 0.0708 0.0883 0.1058 0.9024 3.56270 0.9779 0.8785 0.0352 0.0527 0.0702 0.0875 0.1048 0.8757 5.10280 0.9808 0.8961 0.0351 0.0526 0.0699 0.0872 0.1043 0.8446 7.10290 0.9831 0.9101 0.5520 0.0527 0.0700 0.0872 0.1043 0.8085 9.64300 0.9851 0.9215 0.8290 0.0533 0.0707 0.0879 0.1050 0.7666 12.81310 0.9868 0.9310 0.8522 0.7569 0.0721 0.0895 0.1067 0.7178 16.71320 0.9883 0.9390 0.8709 0.7924 0.6949 0.0925 0.1098 0.6600 21.45330 0.9895 0.9457 0.8864 0.8200 0.7428 0.6453 0.1164 0.5890 27.18340 0.9906 0.9515 0.8993 0.8422 0.7784 0.7042 0.6108 0.4916 34.12350 0.9915 0.9565 0.9103 0.8606 0.8064 0.7462 0.6770

Zdew 0.9587 0.8774 0.8036 0.7389 0.6776 0.6164 0.5518Tdew, K 230.6 269.4 291.3 305.9 317.1 326.4 334.3

The values in this table were generated from the NIST REFPROP software (Lemmon, E. W., McLinden, M. O., and Huber, M. L., NIST Standard Reference Data-base 23: Reference Fluid Thermodynamic and Transport Properties-REFPROP, National Institute of Standards and Technology, Standard Reference Data Program,Gaithersburg, Md., 2002, Version 7.1).

2-144 PHYSICAL AND CHEMICAL DATA

TABLE 2-145 Compressibilities of Liquids*

At the constant temperature T, the compressibility β = (1/V�0)(dV/dP). In general as P increases, β decreases rapidly at first and then slowly; the change of β with T islarge at low pressures but very small at pressures above 1000 to 2000 megabars. 1 megabar = 0.987 atm = 106 dynes/cm2 based upon the older usage, 1 bar = 1 dyne/cm2.

Pres- Compres- Pres- Compres- Pres- Compres-sure, sibility per sure, sibility per sure, sibility per

Temp., mega- megabar Temp., mega- megabar Temp., mega- megabarSubstance °C bars β × 106 Substance °C bars β × 106 Substance °C bars β × 106

Acetone 14 23 111 Ethyl acetate 20 400 75 Methyl alcohol 15 23 103Acetone 20 500 61 alcohol 14 23 100 alcohol 20 200 95Acetone 20 1,000 52 alcohol 20 500 63 alcohol 20 400 80Acetone 40 12,000 9 alcohol 20 1,000 54 alcohol 20 500 65Amyl alcohol 14 23 88 alcohol 20 12,000 8 alcohol 20 1,000 54

alcohol, iso. 20 200 84 bromide 20 200 100 alcohol 20 12,000 8alcohol, iso. 20 400 70 bromide 20 400 82 Nitric acid 0 17 32alcohol, n 20 500 61 bromide 20 500 70 Oils:alcohol, n 20 1,000 46 bromide 20 1,000 54 Almond 15 5 53alcohol, n 20 12,000 8 bromide 20 12,000 8 Castor 15 5 46alcohol, n 40 12,000 8 chloride 15 23 151 Linseed 15 5 51

Benzene 17 5 89 chloride 20 500 102 Olive 15 5 55Benzene 20 200 77 chloride 20 1,000 66 Rapeseed 20 59Benzene 20 400 67 chloride 20 12,000 8 Phosphorus trichloride 10 250 71Bromine 20 200 56 ether 25 23 188 trichloride 20 500 63Bromine 20 400 51 ether 20 500 84 trichloride 20 1,000 47Butyl alcohol, iso 18 8 97 ether 20 1,000 61 trichloride 20 12,000 8

alcohol, iso 20 200 81 ether 20 12,000 10 Propyl alcohol (n) 20 200 77alcohol, iso 20 400 64 iodide 20 200 81 alcohol (n) 20 400 67alcohol, iso 20 500 56 iodide 20 400 69 alcohol (n?) 20 500 65alcohol, iso 20 1,000 46 iodide 20 500 64 alcohol (n?) 20 1,000 47alcohol, iso 20 12,000 8 iodide 20 1,000 50 alcohol (n?) 20 12,000 7

Carbon bisulfide 16 21 86 iodide 20 12,000 8 Toluene 20 200 74bisulfide 20 500 57 Gallium 30 300 3.97 Toluene 20 400 64bisulfide 20 1,000 48 Glycerol 15 5 22 Turpentine 20 74bisulfide 20 12,000 6 Hexane 20 200 117 Water 20 13 49tetrachloride 20 200 86 Hexane 20 400 91 Water 20 200 43tetrachloride 20 400 73 Kerosene 20 500 55 Water 20 400 41

Chloroform 20 200 83 Kerosene 20 1,000 45 Water 20 500 39Chloroform 20 400 70 Kerosene 20 12,000 8 Water 40 500 38Dichloroethylsulfide 32 1,000 34 Mercury 20 300 3.95 Water 40 1,000 33Dichloroethylsulfide 32 2,000 24 Mercury 22 500 3.97 Water 40 12,000 9Ethyl acetate 13 23 103 Mercury 22 1,000 3.91 Xylene, meta 20 200 69

acetate 20 200 90 Mercury 22 12,000 2.37 meta 20 400 60

* Smithsonian Tables, Table 106.Scott (Cryogenic Engineering, Van Nostrand, Princeton, N.J., 1959) gives data for liquid nitrogen (p. 283), oxygen (p. 276), and hydrogen (p. 303). For a convenient

index to the high-pressure work of Bridgman, see American Institute of Physics Handbook, p. 2-163, McGraw-Hill, New York, 1957.

UNITS CONVERSIONS

For this subsection, the following units conversions are applicable:°F = 9⁄5 °C + 32

To convert calories per gram-mole to British thermal units per

pound-mole, multiply by 1.799; to convert calories per gram to Britishthermal units per pound, multiply by 1.799.

To convert millimeters of mercury to pounds-force per square inch,multiply by 1.934 × 10−2.

LATENT HEATS

TABLE 2-146 Compressibilities of Solids

Many data on the compressibility of solids obtained prior to 1926 are contained in Gruneisen, Handbuch der Physik, vol. 10,Springer, Berlin, 1926, pp. 1–52; also available as translation, NASA RE 2-18-59W, 1959. See also Tables 271, 273, 276, 278, andother material in Smithsonian Physical Tables, 9th ed., 1954. For a review of high-pressure work to 1946, see Bridgman, Rev. Mod.Phys., 18, 1 (1946).