Document reMLLaN7B1MwqBkQRZEy5pD1e

American Society of Heating and Ventilating Engineers Guide, 1937 Table 3. Properties of Dichlorodifluoromethane (Flt) Sat. Temp. F Ass Ls pbb Sq In. Volume Liquid Vapor Heat Content and Enteopt Taken Feom --40 F Heat Coateut Liquid I Vapor Entropy Liquid Vapor 25 F Superheat 50 F 8uperheat Ht. Ct Entropy Ht. Ct. I Entropy 0 5 10 IS 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 23.871 .0110] 1.637 8.25 78.21 0.01869 26.51 .0111 1.485 9.32 78.79 0.02097 29.351 0U2| 1.351 10.39 79.36 0.02328 32.44] .0112 1,230 11.48 79.94 0.02556| 35.75, .0113 1.121 12.55 80.49 0.02783 39.33! .0114 1.025 13.66 81.06 0.03008 43.161 .0115 0.939 14.76 81.61 0.03233, 47.28; .0116 0.863 15.88 82,16 0.03458] 51.68 .0116 0.792 17.00 82.71 0.03680! 56.38 0117 0.730 18.14 83.26 0.03904 61.39 0118 0.673 19.27 83.78 0.04126 66.74 0119 0.622 20.41 84.31 0.04348] 72.41 0119 0.575 21.57 84.82 0.04568 78.44 0120 0.532 22.72 85.32 0.04789 84.82 0121 0.493 23.90 85.82 0.05009 91.60 0122 0.45S 25.08 86.32 0.05229] 98.76 0123 0.425 26.28 86.80 0.05446 106.40 0124 0.395 27.48 87.28 0.05665; 114.30 0125 0.368 28.70 87.74 0.05882] 122.80 0126 0.343 29.93 88.19 0.06100] 131.60 0127 0.319 31.16 88.62 0.06316 140.90 0128 0.298 32.40 89.03 0.06534 150.70 0. 0129 0.277 33.65 89.43 0.06749 161.000. 0130 0.258 34.90 89.80 0.06965] 171.800. 0132 0.240 36.16 90.15 0.07180, .17091 81.71 0.17829 85.26 0.18547 17052] 82.29 0.177861 85.89 0.18502 17015] 82.90 0.17747 86.51 0.18460.16981 83.49 0.17710 87.13 0.18420 .16949| 84.09 0.17679 87.76 0.18382 .16920 84.67 0.17643, 88.37 0.18349 16887 85.25 0.17612 88.97 0.18315 16860] 85.83 0.17582 89.56 0.18285 16833 86.41 0.175541 90.16 0.18256 16808 86.96 0.17528| 90.76 0.18227 16785 87.54 0.17505 91.38 0.18203 16763] 88.09 0.17482 91.93 0.18181 16741 88.64 0.17458 92.51 0.18155 16721 89.18 0.17436 93.11 .0.18132 16701 89.72 0.17417] 93.66 0.18114 16681 90.25 0.17397 94.23 0.18092 16662 90.78 0.17379 94.80 0.18075 16644 91.27 0.17361 95.33 0.18056 16624 91.77 0.17344| 95.86 0.18040 16604 92.27 0.173231 96.39 0.18020 16584 92.75 0.17308 96.92 0.18004' 16564 93.24 0.17291 97.46 0.17991 16542 93.66 0.17274| 97.93 0.17976 16520 94.07, 0.172531 98.40 0.17955 16495 94.47 0.17233 98.84 0.17939 ~ 1.138 at 25 C. Table 4. Properties of Water Sat. T^mp. F Abs Press. Lb per Sq In. Volume Liquid Vapor Heat Content and Entropt Taken From --32 F Heat Content liquid Vapor Entropy 50 F Superheat 100 F Superheat liquid Vapor HtCt Entropy Ht. Ct. Entropy 32 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 0.0887 0.01602 3296.0 0.1000 0.01602 2941.0 0.1217 0.01602 2441.0 0.1475 0.01602 2034.0 0.1780 0.01602 1702.0 0.2140 0.01603 1430.0 0.2561 0.01603 1206.0 0.3054 0.01604 1021.0 0.3628 0.01605 868.0 0.4295 0.01606 740.0 0.507 0.01607 632.9 0.596 0.01609 543.3 0.698 0.01610 467.9 0.815 0.01612 404.2 0.949 0.01613 350.3 1.101 0.01615 304.4 0.00 3.02 8.05 13.07 18.08 23.08 28.08 33.08 38.07 43.06 48.05 53.04 58.03 63.01 1073.0 1074.4 0.0000 0.0062 2.1826 2.1724 1096.9 1098.3 2.2277 2.2172 1120.8 1122.2 2.2688 2.2581. 1076.8 1079.2 1081.5 0.0163 0.0262 0.0361 2.1555 2.1390 2.1230 1100.6 1102.9 1105.2 2.2000 2.1832 2.1667 1124.5 1126.7 1129.0 2.2406 2.2234 2.2066 1083.9 0.0459 2.1073 1107.5 2.1506 1131.3 2.1902 1086.2 0.0556 2.0920 1109.8 2.1349 1133.5 2.1742 1088.6 0.0652 2.0771 1112.2 2.1196 1135.8 2.1585 1090.9 1093.2 0.0746 0.0840 2.0625 2.0483 1114.5 1116.7 2.1046 2.0900 1138.1 1140.3 2.1432 2.1283 1095.5 0.0933 2.0344 1119.0 2.0758 1142.5 2.1138 1097.8 0.1025 2.0208 1121.2 2.0619 1144.7 2.0996 1100.0 0.1116 2.0075 1123.4 2.0483 1146.8 2.0857 1102.3 0.1206 1.9946 1125.6 2.0350 1148.9 2.0721- 68.00 72.98 1104.6 0.1296 1.9819 1106.8 0.1384 1.9695 1127.9 2.0220 1151.1 2.0588 1130.2 2.0093 1153.2 2.0458 For properties of steam at high temperatures, see Page 28. Cp " -=E- = 1.33 38 Chapter 2--Refrigeration theoretical cycle starts with saturated vapor, operation is common at a condition of superheated vapor (as at ai). Moreover, expansion may start either with a mixture ofliquid and vapor or with a sub-cooled liquid, as at cu with expansion to ex. It is obvious that this latter is desirable as it increases the refrigerating effect. Area aibicdaax represents the work of such a superheated cycle, while the area e^i/iei represents the refrigera ting effect of the cycle with superheated vapor and sub-cooled refrigerant liquid. It will be noted on the pressure-volume diagram the volume of the saturated liquid is indicated by a dotted line close to and parallel to the ordinate. In the discussions in this chapter a slight error is introduced by not including all of the work of pumping the liquid from the low to the high pressure. This occurs because the liquid line is not a line of equal pressure but of saturation pressures. The error in work per pound of refrigerant Fig. 2. Theoretical Dichlorodifluoromethane (Fu) Cycles figured from total heats, which should be added to the indicated figures is roughly the specific volume of the liquid at the lower pressure and tem perature multiplied by the pressure difference in appropriate units. This error may become of some importance in calculations involving carbon dioxide or in problems involving the liquid of any of the refrigerants, as in figuring expansion valve orifices. Theoretical Work per Pound The temperature-entropy and pressure-volume diagrams are based on one pound of the refrigerant. Likewise, the theoretical work and the refrigerating effects are conveniently based on a pound of refrigerant. The . compression work per pound may be found by several methods. The temperature-entropy method starts with state point a. Since the quality of a is known, the heat content of the vapor is known, and also the entropy Sa. Since Sa = Sb and with T2 given, Hb can be determined. If W = work in foot-pounds per pound of refrigerant, then IF = (Hb - Ha) X 778 (1) 39