Document jrJzO3ZNb92YrRk9nKKw3VKO

440 Chapter 24 1945 Guide -motor losses, less the power transmission fosses and less the heat dis- sipated from the compressor to the surroundings. Refrigerants There are many substances which might be used as refrigerants in mechanical refrigeration systems, but in practice the choice is limited by a wide variety of considerations including availability, cost, safety, chemical stability and adaptability to the type of refrigerating system to be used. . In this chapter detailed consideration is limited to six substances, viz: ammonia, dichlorodifluoromethane (Fu), methyl chloride, carbon dioxide, monofluorotrichloromethane (Fn), and water, properties for each of which are given in Tables 1,2,3,4,5 and 6. Each table gives the principal physi cal properties of the saturated substance, and all are arranged in uniform fashion. In all it will be noted that columns are included which give Low Pressure Saturated Gas NT Heat of Compression Added to Gas _L Compressor Hot tn Heat Aided to Refrigerant by Substance.Copied Cold Out Evaporator or Cooler Expansion Valve for Reducing Pressure High*Pressure Superheated Gas --1/ Condenser Cold In Heat Taken from Refrigerant by Condereing Medium Hot Out . High Pressure Saturated Liquid Fig. 1. Mechanical Refrigeration System the Heat content and entropy of the superheated vapor at two selected points. The first four refrigerants named are used in reciprocating and rotary compressors. The last two are used in centrifugal compressors. Water is also used in steam jet equipment. Types of Compressors There are many different types of compressors, using various refrig erants. Each type has its advantages for its particular application, and those generally used for air conditioning are of the following types: 1. Reciprocating compressors (commonly referred to as piston type). 2. Centrifugal compressors. 3. Steam jet. Reciprocating compressors are available in a wide range of sizes and types. Any of a number of refrigerants, including dichlorodifluoromethane (Fu), methyl chloride, ammonia, carbon dioxide, and sulphur dioxide may be used in reciprocating machines. The first of these is used exten sively in direct expansion systems of comfort air conditioning. , Compressors may be classified into two general types, (a) open type. Refrigeration 441 Table 1. Properties of Ammonia Sat. Temp. F Abs. Press. Lb per SqIn. Volume . liquid Vapor Heat Content and Entropt Taken From >-40 F Heat Content Entropy 100 F Superheat 200 F Superheat Liquid Vapor liquid Vapor - Ht. Ct. Entropy Ht. Ct. Entropy 0 30.42 0.02419 . 2 31.92 0.02424 4 33.47 0.02430 5 34.27 0.02432 6 35.09 0.02435 i 36.77 0.02440 10 38.51- 0.02446 12 40.31 0.02451 14 42.18 0.02457 16 44.12 0.02462 18 . 20 22 24 26 46.13 48.21 50.36 52.59 54.90 0.tl2<S8 0.02474 0.02479 0.02485 0.02491 28 57.28 0.02497 30 59.74 0.02503 32 6239 0.02508 34 64.91 0.02514 36 67.63 0.02521 38 70.43 39 71.87 40 73.32 41 74.80 42 J . 76.31 0.02527 0.02530 0.02533 0.02536 0.02539 44 79.38 0.02545 46 82.55 0.02551 48 85.82 0.02558 50 89.19 0.02564 52 92.66 0.02571 54 96.23 0.02577 56 99.91 0.02584 ' 58 103.7 0.02590 60 107X 0.02597 .62 111.6 0.02604 64 115.7 66 120.0 68 1243 128.8 72* 133.4 0.02611 0.02618 0.02625 0.02632 0.02639 74 * 138.1 76 143.0 147.9 153.0 1583 0.02646 0.02653 0.02661 0.02668 0.02675 84 163.7 0.02684 169.2 0.02691 174.8 0.02699 180.6 0.02707 186.6 0.02715 94 192.7 0.02723 96 198*9 0.02731 205.3 0.02739 211.9 0.02747 218.6 0.02756 104 225.4 0.02764 232.5 0.02773 239.7 0.02782 247.0 0.02790 2543 0.02799 114 262.2 0.02808 270.1 , 0.02817 278.2 0.02827 286.4 0.02836 122 294.8 0.02846 303.4 0.02855 312.2 0.02865 321.2 0.02875 9.116 8.714 8.333 8.150 7.974 7.629 7.304 6.996 6.703 6.425 6.161 5.910 5.671 5.443 5.227 5.021 4.825 4.637 4.459 4.289 4.126 4.048 3.971 3.897 3.823 ' 3.682 3.547 3.418 3.294 3.176 3.063 2.954 2351 2.751 2.656 2.565 2.477 2393 2312 2.235 2.161 2.089 2.021 1.955 1392 1331 1.772 1.716 1.661. 1.609 1359 1310 1.464 1.419 1375 1334 1.293 1.254 1.217 1.180 1.145 1.112 1.079 1.047 1.017 0.987 0.958 0.931 42.9 45.1 47.2 483 49.4 51.6 533 56.0 583 603 62.5 64.7 . 66.9 69.1 713 733 75.7 77.9 80.1 82.3 84.6 85.7 863 87.9 89.0 91.2 933 95.7 97.9 100.2 102.4 104.7 106.9 1093 1113 113.7 116.0 1183 120.5 1223 125.1 127.4 129.7 132.0 1343 136.6 138.9 1413 1433 1453 1483 150.5 152.9 1553 1573 1S9.9 1623 164.6 167.0 169.4 171.8 1743 176.6 179.0 181.4 183.9 1863 1883 6113 612.4 613.0 6133 613.6 0.0975 0.1022 0.1069 0.1092 0.1115 13352 13312 13273 13253 13234 6663 667.6 668.4 6683 669.3 6143. 614.9 6153 616.1 616.6 0.1162 0.1208 0.1254 0.1300 0.1346 13195 13157 13118 1.3081 13043 670.1 670.9 671.7 672.5 673.4 6173 6173 6183 618.9 619.4 0.1392 13006 0.1437 13969 0.1483. - 1.2933 0.1528 1.2897 0.1573 13861 674.2 675.0 6753 676.6 677.3 619.9 6203 621.0 6213 622.0 0.1618 0.1663 0.1708 0.1753 0.1797 1.2825 1.2790 13755 1.2721 13686 . 678.1 678.9 679.7 680.4 6813 6223 622.7 623.0 6233 623.4 0.1841 0.1863 0.1885 0.1908 0.1930 13652 13635 13618 13602 1.2585 6813 682.3 682.7 683.1 683.4 623.9 624.4 6243 625.2 625.7 0.1974 03018 03062 03105 03149 1.2552 1.2519 13486 13453 13421. 6843 6843 685.6 686.4 687.1 626.1 6263 6263 6273 627.7 03192 0.2236 03279 0.2322 03365 13389 1.2357 1.2325 13294 1.2262 6873 688.5 689.2 6893 690.6 628.0 628.4 6283 629.1 629.4 0.2408 03451 03494 03537 03579 13231 1.2201 13170 1.2140 1.2110 6913 6913 692.6 693.3 694.0 6293 630.1 630.4 630.7 631.0 03622 03664 0.2706 03749 03791 1.2080 1.2050 13020 1.1991 1.1962 694.6 6953 695.9 696.6 6973 6313 6313 6313 632.0 6323 03833 0.2875 0.2917 0.2958 03000 1.1933 1.1904 1.1875 1.1846 1.1818 6973 6983 699.1 699.7 7003 6323 632.6 6323 633.0 6333 0.3041 03083 03125 03166 03207 1.1789 1.1761 1.1733 LI705 L1677 700.9 7013 702.1 702.7 7033 633.4 6333 633.6 633.7 6333 03248 03289 03330 03372 03413 1.1649 1.1621 1.1593 1.1566 1.1538 7033 7043 705.0 7053 .706.1 6333 634.0 634.0 634.0 0.3453 03495 03535 03576 1.1510 1.1483 1.1455 1.1427 706.6 7073 707.7 7083 634.0 634.0 6333 6333 03618 03659 03700 03741 1.1400 1.1372 1.1344 1.1316 708.6 709.1 709.6 710.0 1.4439 1.4400 1.4360 1.4340 1.4321 1.4281 1.4242 1.4205 1.4168 1.4130 1.4093 1.4056 1.4021 13985 13950 13914 1.3879 13846 13812 13779 13745 13729 13712 13696 13680 13648 13616 13584 13552 13521 13491 1.3460 13430 13399 13370 13341 13312 13283 13254 13226 13199 13171 13144 13116 13089 13063 13040 13010 13983 13957 13932 13906 13881 1.2855 1.2830 13805 13780 13755 1.2731 13708 1.2684 13661 1.2636 13612 1.2587 1.2563 1.2538 1.2513 7203 7213 7223 722.6 723.1 724.1 725.0 725.9 7263 7273 728.7 729.6 7303 731.4 732.4 7333. 7343 735.1 736.0 7363 737.7 7383 738.6 739.0 7393 740.4 7413 7423 743.1 744.0 7443 745.7 746.5 747.4 7483 749.1 7493 7503 751.6 752.4 7533 754.1 755.0 7553 7563 757.4 7583 759.1 7593 760.7 7613 7623 7633 7633 764.6 7653 766.1 7663 767.6 7683 769.1 7693 7703 7713 772.0 7723 773.5 7743 13317 13277 13236 13216 13196 13155 13115 13077 13039 13001 1.4963 1.4925 1.4889 1.4853 1.4816 1.4780 1.4744 1.4710 1.4676 1.4643 1.4609 1.4592 1.4575 1.4559 1.4542 1.4510 1.4477 1.4445 1.4412 1.4382 1.4351 1.4321' 1.4290 1.4260 1.4231 1.4202 L4172 1.4143 L4114 1.4086 1.4059 L4Q31 1.4004 13976 13949 13923 13896 13870 13843 13818 13793 13768 13743 13718 13693 13668 13643 13619 13596 13573 13550 13527 13503 13479 13455 13431 13407 1.3383