Document 0gYKY7bkZe2jz3Z22N2d9JOXb
American Society of Heating and Ventilating Engineers Guide, 1935
Table 1. Properties of Dry Air3 Barometric Pressure 29.921 In.
Temperature
Deo F
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 180 200 220 240 260 280 300 . 350 400 450 500 550 600 700 800 900 1000
Weight per Cu Ft Pounds
0.08636 0.08453 0.08276 0.08107 0.07945 0.07788 0.07640 0.07495 0.07356 0.07222 0.07093 0.06968 0.06848 0.06732 0.06620 0.06510 0.06406 0.06205 0.06018 0.05840 0.05673 0.05516 0.05367 0.05225 0.04903 0.04618 0.04368 0.04138 0.03932 0.03746 0.03423 0.03151 0.02920 0.02720
Per Cent op Volume at 70 F
0.8680 0.8867 0.9057 0.9246 0.9434 0.9624 0.9811 1.0000 1.0190 1.0380 1.0570 1.0756 1.0945 1.1133 1.1320 1.1512 1.1700 1.2080 1.2455 1.2833 1.3212 1.3590 1.3967 1.4345 ' 1.5288 1.6230 1.7177 1.8113 1.9060 2.0010 2.1900 2.3785 2.5670 2.7560
Btu Absorbed by One Cu Ft Dry Am
per Deo F * 0.02080 0.02039 0.01998 0.01957 0.01919 0.01881 0.01846 0.01812 0.01779 0.01747 0.01716 0.01687 0.01659 0.01631 0.01605 0.01578 0.01554 0.01506 0.01462 0.01419 0.01380 0.01343 0.01308 0.01274 0.01197 0.01130 0.01070 0.01018 0.00967 0.00923 0.00847 0.00782 0.00728 0.00680
Cu Ft Dry Am
Warmed One Degree per Btu
48.08 49.05 50.05 51.10 52.11 53.17 54.18 55.19 56.21 57.25 58,28 59.28 60.28 61.32 62.31 63.37 64.35 66.40 68.41 70.48 72.46 74.46 , 76.46 78.50 83.5588.50 93.46 . 98.24 103.42 ' 108.35 118.07 127.88 137.37 147.07
From Pan Engineering.
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t
t
-i
Chapter 1--Fundamentals of Heating and Air Conditioning
It is usual to assume that dry air, moist air, and the water vapor in the air follow the laws of perfect gases. This assumption while not absolutely true, especially with saturated vapor at temperatures much above 140 F,
Table 2. Properties of Saturated Air3 Weights of Air, Vapor of Water, and Saturated Mixture of Air and Vapor at 29.921 Inches of Mercury
' Temp. Deg F
orWeight in a Cubic Foot
Mixture
Btu Absorbed by Cubic Feet Sat. SpECIPIC
Weight op
Dry Am Pounds
Weight op Vapor Pounds
Total Weight op the Mixture Pounds
Sat. Am per Deg F
Degree per Btu
per Pound op Mixture
0
0.08625 0.000068
0.08632
0.02083
48.02
0.2413
10
0.08433
0.000110
0.08444
0.02039
49.05
0.2415
20
0.08246 0.000176
0.08264
0.01998
50.07
0.2418
30
0.08062 0.000277
0.08090
0.01958
51.07
0.2420
40
0.07878 0.000409
0.07919
0.01921
52.06
0.2426
50
0.07694 0.000587
0.07753
0.01885
53.05
0.2431
60
0.07506 0.000828
0.07589
0.01851
54.02
0.2439
70
0.07310 0.001151
0.07425
0.01819
54.97
0.2450
80
0.07103 0.001578
0.07261
0.01790 55,87
0.2465
90
0.06879 0.002134
0.07092
0.01762
56,76
0.2485
100
0.06635 0.002850
0.06920
0.01736
57.59
0.2509
110
0.06364 0.003762
0.06740
0.01714
58.35
0.2543
120
0.06060 0.004914
0.06551
0.01695
59.00
0.2587
130
0.05715 0.006351
0.06350
0.01679
59.56
0.2644
140
0.05319 0.008120
0.06131
0.01668
59.96
0.2721
150
0.04864 0.010295
0.05894
0.01662
60.17
0.2820
160
0.04340 0.012936
0.05634
0.01662
60.17
0.2950
170
0.03734 0.016108
0.05345
0.01668
59.96
0.3121
180
0.03035 0.019896
0.05025
0.01684
59.38
0.3351
190
0.02228 0.024400
0.04668
0.01710
58.49
0.3663
200
0.01300 0.029715
0.04272
0.01749
57.18
0.4094
210
0.00230 0.035938
0.03824
0.01802
55.50^
0,4712
212
0.00000 0.037307
0.03731
0.01815
55.10
0.4865
From Fan Engineering.
is sufficiently accurate for practical purposes and it greatly' simplifies computations.
Boyle's Law refers to the relation between the pressure and volume of a gas, and may be stated as follows: With temperature constant, the volume of a given weight of gas varies inversely as its absolute pressure. Hence, if Pi and Pi represent the initial and final absolute pressures, and Vi and Vi represent corresponding volumes of the same mass, say one pound of
yp
gas, then -jy = -=/, or Pi Vi = Pt Vt, but since Pi Vi for any given case is
Vt Jri
a definite constant quantity, it follows that the product of the absolute
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