Document MGY0BQO1gGgZNEgkGyrJKgaKa

40 CHAPTER 3 1965 Guide And-Qqtpj.Book Ah*. frm th/Sq In. P 14.696 16 18 20 22 24 26 28: 30 32 34 36 38 40 42 44 46 48 50 52. 54 56 58 60: 62 64 66 68 70 72 74 76 78 80 82 84 .88 88 90 92 94 96 98 100 150 200 300 400 500 -Table,4jv.> . Prppertios'of SATURATED STEAM:,Pressure Table*-: temp. F .. X't >r- 212.00 216-32 222.41 227.96 233.07 237.82 242.25 246.41 250.33 254.05 257.58 260.95 284.16 267.25 270.21 273.05 275.80 278.45 281.01 283.49 285.90 288.23 290.50 292.71 294.85 296.94 .298.99 300.98 302.92 304.83 306.68 308.50 310.29 ; 312.03 313.74 315.42 317.07 318.68 : 320.27 321.83 323.36 324.87 326.35 327.81 358.42 381.79 417.33 444.59 467.01 , S{*cHk Volvo* bdbtdpy . . . Entropy Set Liquid Set Vapor - > -it, Sat Uqrid Evap. . b, . 2 Set Vapor Sat liquid Evap. 0.01672 - 26.80 180.07 970.3 1150.4 0.01674, 24.75 i ::184.42 . : 967.6; >'3152.0 0.01679 : i,' 22.17 - : 190.56 ;; 963.6- -.1154.2 0.01683; 20.089. ! ; :196.16 * , 960.1- 1156-3 0.01687 >,Vr: 18.375- : (201.33 .. 956.8 '1158.1 0.01691 r.l:r:J6.938 ; ,206.14 ; 953.7: 1159.8 0.01694 (V;-15.715 i > 210.62 H: 950.7; 1161.3 .0.01698; 14.663 - ,214.83 - .1 947.9 1162.7 0.3120 r 0:3184 0.3275 , >0:3366 0.3431 . .0.3500 : 0.3564 > , 0.3623 : 0.01701.0:01704: 0.01707j 0.01709: 0.01712' 0.01715' 0.01717. 0.01720 0.01722 0.01725 L- ' 13.746 I 218.82 945.3' 1 1164.1 12.940 222 59 1 " 942.8 11165.4 >' - 12.228'-; 228.18 940.3 ` 1166.5 , 11.588 229.60 938.0 1167.6 11.015 232.89- S1 935.8 1168.7 -10.498 ! 236-03 " 933.7- 1169.7 *'! 10.029 239.04 J- 931.6- 1170.7 1-'- '9.601' - ` 241.95 ' 929.6 1 1171.6 9.209- ` 244.75 i? 927.7 1172.4 '' -' 8.848- - `247.47 2 925.8 1173.3 0.3680 4 0.3733 : 0<3783 ; 0.3831 ; 0:3876 ' 0:3919 . 0.3960 I 0:4000 > - 0:4038 > 0.4075 : 0.01727' ,0.01729 0.01731 0.01733. 0.01736 .0.01738 .0.017401 0.01742 0.01744s 0.01746; = ' ;8.515. ' 250.09 1. 924.0 !:U74.1 - 0.41101 r, - - ,8.208- - - 252.63 ; 922.2 1174.8 .0.4144 -V ,7.923,- . 255.09 920.5 11756 0!4177 i '7.656 ' 257.50 918.8 ' 1176.3 0.4209 ; -- -.7.407- , < .259.82 . 917.1- ,,-1176.9 . 0.4240 ~;":,7.175 ' ,262.09 . . 915.5- ;1177.6 '0.4270 6.957. . , 264.30 . 913.9. r. 1178.2 : 0:4300 ; - .6.752 , ! 1266.45 ,, 912.3 1178.8 0:4328 : : ;,6.660 . 288.55 ` ,' 910.8- - ,1179.4 ' 0:4356 '.:: '.`6.378. ;;270.go . ... 909.4 ,. 1180.0 0.4383 ; 0.01748. : 0.01750, 0.01752 0.01754 0.01755 0.01757 0.01759: 0.01761' 0.01762 0:01764! V.;' -6.206.- ^272.61. 907.9- 6.044 : ';274.57 906.6 5.890 - H276.49. C 905.1 .^5.743;... : 278.37.; 903.7,1 5.604 280.21 902.4 . >....5.472 -1282.02 . 901.1- -.5.346 : ' 283.79 . 899.7, u l :-5.2 ;-285.53.. > 898.5 - , / 5.111 i;287.24 897.2. - * , 5.001 ;; j.288.91.; .! 895.9; 1180.6 : 0.4409, 1181.1 0.4435 1181.6 . 0.4460 : 0.4484 i 1182.6 0.4508 : 1183.1 0-4531. 1183.5 , .0.4554 1184.0 0.4576 <.1184.4 - -0.4598 ! '1184.8 ; 0.4620 0:01766 .0.01768 0.017691 0.01771; 0.01772 0.017741 0.01809 0.01839: 0.01890 0.0193 ' 0.0197 ; ?' 4.896 !;290.58 1 894.7-' 4.796'-'' '.'.292.18- ' 893.6' ! 4.699 - ';293.78 ` 892.3- !'4.606 ' >295.34 " 891.1 :,4.517 l! !296.89` ! 889.9- 4.432 298.40 888.8 V- 3.015 :`330.51 o ' 863.6 - '2.288-1" !355.36 ' 1 843.0 1.5433 '393.84 - 809.0 i1- *'1.1613'* !424.0- 780.5 > 0.9278" 449.4 - 1 755.0 1185.3 0.4641 1185.7 ' 0.4661 -1186.1 ' ' 0:4682 '1186.4 `0:4702: 1186.8 0.4721: 1187.2 0.4740: 1194.1 -0:5138 1193.4 0.5435: 1202.8 ' 0.5879! 1204.5 0:62141 -1204.4 ; 0.6487 1.4446 1.4313. .1.4128. 1.3962 1.3811j 1.3672 ,1.3544 1.3425 1.3313 1.3209 1.3110 1.3017 1:2929 1:2844' 1:2764' 1.2687 1.2613 112542 1.2474* ,1.2409 1.2346 1.2285' .1.2228 ivies' 1.2112 1.2059. I.2006 1.1955 1.1906 -1.1857, 1.1810 1.1764 1.1720 1.1676 11633 1.1592 1.1551, i;i5iq 1-1471 1.1433 11394 1.1358 1.1322 1.1286 1.0556 1:0018 0:9225 0:8630 0!8147 Ah*. Sat Vopor ' Ch/Sq fa. . * `1 ; Pr ' 1.7566 , 1.7497; 1.7403 ' 1.7319: 1.7242 1.7172 1.7108: 1.7048- ' ` ! 14.696 16 _ 18 - 20 22 ' : 24; 26 : . 28 : 1.6993 ' 1.6941- ! 1-.6893- 1.6848 1.6805. ; 1.6763v . 1.6724r' } : 1.6687 1.6652. : 1.66171.' 30 " 32- 34:- 36 38 -: 40'": 42 a 44-L-v 46 48 - . 1.6585:. j 50 . 1.6553* ' 52 1.6523 ; 54.; 1.6494 : 56 i 1.6466. : 58. 116438. ' 60 ; l`.64i2;: { 62 ! r.63S7" : M 1.6362' > 66 ; 1.6338;- i '68"-' 1.6315 70 1.6292 72 1.6270 74 .- 1.6248 76 , 1.6228 78 - 1.6207. 80 1.6187: ; 82 - 1.6168. : 84 , 1.6149 86- 1.6130 1 88- 1.6112- 90 - : 1.6094 92-.: 1.6076 1.6060 1 06-- 1.6043 98 . 1.6026 . 100 1.5694 > 150 1.5453 200 . ' 1.5104 ! 300 1.4844' 400- ! 1.4634- < 500; * Reprinted by perroitticm from Tkfrmmiiatmic Prtperiia af Sl*am, by J. H. Keenmeod P. O. Kejrm publisbed by John Wiiey and Son*. Idc., lSSSeditioa. Toble 5 ... Coefficients A, B, C, Appearing m Equations ;3, 5, 7,(Maximum -Values of Corrections Defined by Equations 3, 5, 7. 0egree of Saturation'at: Which TheseThree Maxima' Occur/ Pm, Maximum Value of Correction . ; Defined by:Equation 8, qn'd Degree ofSaturatianat WhicJiTHs Maximum Occurs, jz*. i ~ r. ' (Standard MmotphoneFtotton) t_, .. , - .< (F) A: (ft'/lb.) -,B; - - li(( C i i l 4cm* i ' . ftacc.'' li,, ! (Btu/lb.) (Btu/F/Ib.) (ftyib.) (Btu/lb.) (Btu/F/lb.) ; pi, 1 JuMC (Btu/F/Ib.) 4. ' j m 128 1 144 160 176 ' J 192 ' -0.0018; 0.00421 0.0096' ' 0.0215: 0.0487 01169 ' 0.3363 ' 0.0268 ? 0.00004 0.0650 ; 0.00000 0:1439 0.00020 013149 `0.00042' 0.6969 0.00091 1.636 / ' =-0.00207 4.608 0.00567 0.0004' " 0.0010 > 0.0022- 0.0047 0.0099 0.0207' ` 0.0451 0.0069 0.01550.0332 0.0693 0.1418 - 0.2903 0.6180 0.00001s 0.00002 0.00005 0.00009 0.00019 0.00037 0.00076 .0.4925 ` :0.0015 n 0.4878 0.0025 * (1 0.4805' 0.0040 ' 0.4691= 0.0065 > 0 hkk7 0.4511 0.0106 n tfri 0:4213 - -'>'0.0179 . 0.3363 0.3662 0.0333 0.3129 Psychrometrics - sAife.te* occupied by ". moto of water vapor at the same feanperatore but at pressure p is w ,, BT (11) P- According to Daltoo's Rule ; i o.flT *JIT (n* + (12) P. ,, . ,uTM -froni EouatioD 12 that the so-called partial IL^f ea^co^tuent is ite'mol-fraction multiplied by_ Sr^sure of the mixture. Thus - ; (13) (14) Equations 13 and 14'may be regarded as Ike Dalton Rule ' defi2tion of partial pressure in terms of the observable terms "*me taddity ratio W to the mol-mtio g; theratioofmolecularweights,namely, 18.016/28.966 ~ 0.622. Hence, from Equations 13 and 14 IF " 0.622- (15) In this section, it is assumed that Dalton's Rule may be __ it_i r-. _..wativV <l well as unsaturated moist air. ror 41 ExompU t: Rework Example t using perfects relations and steam table data. ,, __ . . ,* ., Solxttim: From Equations 9 and 20 to 22, and using a* " */ 1F/(Q.4441* + 1061 ~ Jw*) - P-240 (< - <*) Wm 0.444 t + 1061 -, A,* From Table 2, p* - 0.68002 in. Hg, and Ay* * 31.08 Btu/lb of water. By Equation 16 # _ (0.622)(0,58002)^ _ Q [b water/lb dry ^ ` 29.341 (0,01230)((0.444K63) + 1061 - 31.08] - (0.240)(27) IF ~ (0.444) (90) + 1061 - 31.08 - 0.006102 lb water/lb'dry air From Table 2, p*. - 1-4219 in. Hg. By Equation 16 W, ^ (-622)(E4219) = 0.03103 lb water/lb dry air 28.499 . From Equation 1 0.006102 0.1963 0.03103 From Equations 20 to 22 h - (0.240)(90) + (0.006102) ((0.444) (90) +10611 .-*'28.32 Btu/lb dry air From Equation 19 ' (53.35)(549.67)__ , .. 4ft7Rwo AQ6102) 1 IF. - 0.622------ P - P (J6) Earlier in this chapter, relative humidity <t> was defined as the ratio of the mol-fraction of water vapor in moist ^*9-",,.. mol-fraction of water vapor in saturated moist' air at the ettm/. temperature and total pressure. According to this defi nition and Equation 13 07) Pm, Equations 15 to 17 may be combined to yield a relation between relative humidity arid degree of saturation. Thus -------- ?---------- ; i -n : 08) - Comparison of the results of Example 1 with those of Ex ample g shows that the perfect-gas relations mayjjve answers very cloy to those of the more exact procedure. U. S. STANDARD ATMOSPHERE The definition of the U. S. Standard Atmosphere is useful to the air-conditioning engineer as a standard of reference for estimating barometric pressure at various altitudes. The definition of the Standard Atmosphere includes the following statements: , 1. There is a linear decrease of temperature T with altitude Z up to the lower limit of the isothermal atmosphere at 35, 332 it according to the relation ( T - T* -- 0.003566 Z ,(?3) Both <f> and p havethe value zero for dry air and the vajue unity for saturated moist air. At intermediate states they may differ and substantially so at higher temperatures. - A Dalton Rule explosion for volume of moist air per pound of dry air obtainable from Equation 12 is ' , , R'T: U -M.(i + 1.6078 (T)' <!9> p -,p. P According to Dalton's Rule, the enthalpy of moist air to the' sum of separate contributions from the dry air and the water vapor. Thus, per pound of dry air ' ft - t +.IFA. " . . (2).' where, to be consistent, the specific enthalpies h (dry air) and A, (water vapor) should be allowed to vary with tempera ture only. Within the accuracy of Dalton's Rule, the follow ing equations give suitable values for ft* and ft,: .< A. - 0.240 t 1 : ., V';V r (21) h. = 0.444 ( + 106r. ' ;: ' . (22), Table 6.... Pressure and Temperature for Altitudes in U. S. Standard Atmosphere__________________ AOitod* Fmt Preunt la. of Hg -,p T -V. -. 4- -1,000 --500 .o +500 +1,000 ' +5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 . 'c ` 50,000 > 31.02' 30i7 29.92129.38 28-86 24.89 '20.58 16.88 13 75 . 11.10 8.88 7.04 5.54 4.36. . 3.436 ^ +62.6 +60.8 +59.0' +57-2 . , +55.4 * +41-2 -+23-4 . +5.5 - -12.3 . -301.... . .. -47.9-