HEAT UNITS PER POUND AND
WEIGHT PER CUBIC FOOT OF WATER
BETWEEN 32 DEGREES FAHRENHEIT AND
340 DEGREES FAHRENHEIT
_________________________________
| | | |
|Temperature|Heat Units| Weight |
| Degrees | per | per |
| Fahrenheit| Pound |Cubic Foot|
|___________|__________|__________|
| | | |
| 32 | 0.00 | 62.42 |
| 33 | 1.01 | 62.42 |
| 34 | 2.01 | 62.42 |
| 35 | 3.02 | 62.43 |
| 36 | 4.03 | 62.43 |
| 37 | 5.04 | 62.43 |
| 38 | 6.04 | 62.43 |
| 39 | 7.05 | 62.43 |
| 40 | 8.05 | 62.43 |
| 41 | 9.05 | 62.43 |
| 42 | 10.06 | 62.43 |
| 43 | 11.06 | 62.43 |
| 44 | 12.06 | 62.43 |
| 45 | 13.07 | 62.42 |
| 46 | 14.07 | 62.42 |
| 47 | 15.07 | 62.42 |
| 48 | 16.07 | 62.42 |
| 49 | 17.08 | 62.42 |
| 50 | 18.08 | 62.42 |
| 51 | 19.08 | 62.41 |
| 52 | 20.08 | 62.41 |
| 53 | 21.08 | 62.41 |
| 54 | 22.08 | 62.40 |
| 55 | 23.08 | 62.40 |
| 56 | 24.08 | 62.39 |
| 57 | 25.08 | 62.39 |
| 58 | 26.08 | 62.38 |
| 59 | 27.08 | 62.37 |
| 60 | 28.08 | 62.37 |
| 61 | 29.08 | 62.36 |
| 62 | 30.08 | 62.36 |
| 63 | 31.07 | 62.35 |
| 64 | 32.07 | 62.35 |
| 65 | 33.07 | 62.34 |
| 66 | 34.07 | 62.33 |
| 67 | 35.07 | 62.33 |
| 68 | 36.07 | 62.32 |
| 69 | 37.06 | 62.31 |
| 70 | 38.06 | 62.30 |
| 71 | 39.06 | 62.30 |
| 72 | 40.05 | 62.29 |
| 73 | 41.05 | 62.28 |
| 74 | 42.05 | 62.27 |
| 75 | 42.05 | 62.26 |
| 76 | 44.04 | 62.26 |
| 77 | 45.04 | 62.25 |
| 78 | 46.04 | 62.24 |
| 79 | 47.04 | 62.23 |
| 80 | 48.03 | 62.22 |
| 81 | 49.03 | 62.21 |
| 82 | 50.03 | 62.20 |
| 83 | 51.02 | 62.19 |
| 84 | 52.02 | 62.18 |
| 85 | 53.02 | 62.17 |
| 86 | 54.01 | 62.16 |
| 87 | 55.01 | 62.15 |
| 88 | 56.01 | 62.14 |
| 89 | 57.00 | 62.13 |
| 90 | 58.00 | 62.12 |
| 91 | 59.00 | 62.11 |
| 92 | 60.00 | 62.09 |
| 93 | 60.99 | 62.08 |
| 94 | 61.99 | 62.07 |
| 95 | 62.99 | 62.06 |
| 96 | 63.98 | 62.05 |
| 97 | 64.98 | 62.04 |
| 98 | 65.98 | 62.03 |
| 99 | 66.97 | 62.02 |
| 100 | 67.97 | 62.00 |
| 101 | 68.97 | 61.99 |
| 102 | 69.96 | 61.98 |
| 103 | 70.96 | 61.97 |
| 104 | 71.96 | 61.95 |
| 105 | 72.95 | 61.94 |
| 106 | 73.95 | 61.93 |
| 107 | 74.95 | 61.91 |
| 108 | 75.95 | 61.90 |
| 109 | 76.94 | 61.88 |
| 110 | 77.94 | 61.86 |
| 111 | 78.94 | 61.85 |
| 112 | 79.93 | 61.83 |
| 113 | 80.93 | 61.82 |
| 114 | 81.93 | 61.80 |
| 115 | 82.92 | 61.79 |
| 116 | 83.92 | 61.77 |
| 117 | 84.92 | 61.75 |
| 118 | 85.92 | 61.74 |
| 119 | 86.91 | 61.72 |
| 120 | 87.91 | 61.71 |
| 121 | 88.91 | 61.69 |
| 122 | 89.91 | 61.68 |
| 123 | 90.90 | 61.66 |
| 124 | 91.90 | 61.65 |
| 125 | 92.90 | 61.63 |
| 126 | 93.90 | 61.61 |
| 127 | 94.89 | 61.59 |
| 128 | 95.89 | 61.58 |
| 129 | 96.89 | 61.56 |
| 130 | 97.89 | 61.55 |
| 131 | 98.89 | 61.53 |
| 132 | 99.88 | 61.52 |
| 133 | 100.88 | 61.50 |
| 134 | 101.88 | 61.49 |
| 135 | 102.88 | 61.47 |
| 136 | 103.88 | 61.45 |
| 137 | 104.87 | 61.43 |
| 138 | 105.87 | 61.41 |
| 139 | 106.87 | 61.40 |
| 140 | 107.87 | 61.38 |
| 141 | 108.87 | 61.36 |
| 142 | 109.87 | 61.34 |
| 143 | 110.87 | 61.33 |
| 144 | 111.87 | 61.31 |
| 145 | 112.86 | 61.29 |
| 146 | 113.86 | 61.27 |
| 147 | 114.86 | 61.25 |
| 148 | 115.86 | 61.24 |
| 149 | 116.86 | 61.22 |
| 150 | 117.86 | 61.20 |
| 151 | 118.86 | 61.18 |
| 152 | 119.86 | 61.16 |
| 153 | 120.86 | 61.14 |
| 154 | 121.86 | 61.12 |
| 155 | 122.86 | 61.10 |
| 156 | 123.86 | 61.08 |
| 157 | 124.86 | 61.06 |
| 158 | 125.86 | 61.04 |
| 159 | 126.86 | 61.02 |
| 160 | 127.86 | 61.00 |
| 161 | 128.86 | 60.98 |
| 162 | 129.86 | 60.96 |
| 163 | 130.86 | 60.94 |
| 164 | 131.86 | 60.92 |
| 165 | 132.86 | 60.90 |
| 166 | 133.86 | 60.88 |
| 167 | 134.86 | 60.86 |
| 168 | 135.86 | 60.84 |
| 169 | 136.86 | 60.82 |
| 170 | 137.87 | 60.80 |
| 171 | 138.87 | 60.78 |
| 172 | 139.87 | 60.76 |
| 173 | 140.87 | 60.73 |
| 174 | 141.87 | 60.71 |
| 175 | 142.87 | 60.69 |
| 176 | 143.87 | 60.67 |
| 177 | 144.88 | 60.65 |
| 178 | 145.88 | 60.62 |
| 179 | 146.88 | 60.60 |
| 180 | 147.88 | 60.58 |
| 181 | 148.88 | 60.56 |
| 182 | 149.89 | 60.53 |
| 183 | 150.89 | 60.51 |
| 184 | 151.89 | 60.49 |
| 185 | 152.89 | 60.47 |
| 186 | 153.89 | 60.45 |
| 187 | 154.90 | 60.42 |
| 188 | 155.90 | 60.40 |
| 189 | 156.90 | 60.38 |
| 190 | 157,91 | 60.36 |
| 191 | 158.91 | 60.33 |
| 192 | 159.91 | 60.31 |
| 193 | 160.91 | 60.29 |
| 194 | 161.92 | 60.27 |
| 195 | 162.92 | 60.24 |
| 196 | 163.92 | 60.22 |
| 197 | 164.93 | 60.19 |
| 198 | 165.93 | 60.17 |
| 199 | 166.94 | 60.15 |
| 200 | 167.94 | 60.12 |
| 201 | 168.94 | 60.10 |
| 202 | 169.95 | 60.07 |
| 203 | 170.95 | 60.05 |
| 204 | 171.96 | 60.02 |
| 205 | 172.96 | 60.00 |
| 206 | 173.97 | 59.98 |
| 207 | 174.97 | 59.95 |
| 208 | 175.98 | 59.93 |
| 209 | 176.98 | 59.90 |
| 210 | 177.99 | 59.88 |
| 211 | 178.99 | 59.85 |
| 212 | 180.00 | 59.83 |
| 213 | 181.0 | 59.80 |
| 214 | 182.0 | 59.78 |
| 215 | 183.0 | 59.75 |
| 216 | 184.0 | 59.73 |
| 217 | 185.0 | 59.70 |
| 218 | 186.1 | 59.68 |
| 219 | 187.1 | 59.65 |
| 220 | 188.1 | 59.63 |
| 221 | 189.1 | 59.60 |
| 222 | 190.1 | 59.58 |
| 223 | 191.1 | 59.55 |
| 224 | 192.1 | 59.53 |
| 225 | 193.1 | 59.50 |
| 226 | 194.1 | 59.48 |
| 227 | 195.2 | 59.45 |
| 228 | 196.2 | 59.42 |
| 229 | 197.2 | 59.40 |
| 230 | 198.2 | 59.37 |
| 231 | 199.2 | 59.34 |
| 232 | 200.2 | 59.32 |
| 233 | 201.2 | 59.29 |
| 234 | 202.2 | 59.27 |
| 235 | 203.2 | 59.24 |
| 236 | 204.2 | 59.21 |
| 237 | 205.3 | 59.19 |
| 238 | 206.3 | 59.16 |
| 239 | 207.3 | 59.14 |
| 240 | 208.3 | 59.11 |
| 241 | 209.3 | 59.08 |
| 242 | 210.3 | 59.05 |
| 243 | 211.4 | 59.03 |
| 244 | 212.4 | 59.00 |
| 245 | 213.4 | 58.97 |
| 246 | 214.4 | 58.94 |
| 247 | 215.4 | 58.91 |
| 248 | 216.4 | 58.89 |
| 249 | 217.4 | 58.86 |
| 250 | 218.5 | 58.83 |
| 260 | 228.6 | 58.55 |
| 270 | 238.8 | 58.26 |
| 280 | 249.0 | 57.96 |
| 290 | 259.3 | 57.65 |
| 300 | 269.6 | 57.33 |
| 310 | 279.9 | 57.00 |
| 320 | 290.2 | 56.66 |
| 330 | 300.6 | 56.30 |
| 340 | 311.0 | 55.94 |
|___________|__________|__________|
The gain due to superheat cannot be predicted from the formula for the
efficiency of a perfect steam engine given on page 119. This formula is
not applicable in cases where superheat is present since only a
relatively small amount of the heat in the steam is imparted at the
maximum or superheated temperature.
The advantage of the use of high pressure steam may be also indicated by
considering the question from the aspect of volume. With an increase of
pressure comes a decrease in volume, thus one pound of saturated steam
at 100 pounds absolute pressure occupies 4.43 cubic feet, while at 200
pounds pressure it occupies 2.29 cubic feet. If then, in separate
cylinders of the same dimensions, one pound of steam at 100 pounds
absolute pressure and one pound at 200 pounds absolute pressure enter
and are allowed to expand to the full volume of each cylinder, the
high-pressure steam, having more room and a greater range for expansion
than the low-pressure steam, will thus do more work. This increase in
the amount of work, as was the increase in temperature, is large
relative to the additional fuel required as indicated by the total heat.
In general, it may be stated that the fuel required to impart a given
amount of heat to a boiler is practically independent of the steam
pressure, since the temperature of the fire is so high as compared with
the steam temperature that a variation in the steam temperature does not
produce an appreciable effect.
The formulae for the algebraic expression of the relation between
saturated steam pressures, temperatures and steam volumes have been up
to the present time empirical. These relations have, however, been
determined by experiment and, from the experimental data, tables have
been computed which render unnecessary the use of empirical formulae.
Such formulae may be found in any standard work of thermo-dynamics. The
following tables cover all practical cases.
Table 22 gives the heat units contained in water above 32 degrees
Fahrenheit at different temperatures.
Table 23 gives the properties of saturated steam for various pressures.
Table 24 gives the properties of superheated steam at various pressures
and temperatures.
These tables are based on those computed by Lionel S. Marks and Harvey
N. Davis, these being generally accepted as being the most correct.