SPECIFIC HEAT OF AIR
AT CONSTANT PRESSURE AND VARIOUS TEMPERATURES
______________________________________________________________
| | | |
| Temperature Range | | |
|_________________________|_______________|____________________|
| | | | |
| Degrees | Degrees | Specific Heat | Authority |
| Centigrade | Fahrenheit | | |
|____________|____________|_______________|____________________|
| | | | |
| -30- 10 | -22- 50 | 0.2377 | Regnault |
| 0-100 | 32- 212 | 0.2374 | Regnault |
| 0-200 | 32- 392 | 0.2375 | Regnault |
| 20-440 | 68- 824 | 0.2366 | Holborn and Curtis |
| 20-630 | 68-1166 | 0.2429 | Holborn and Curtis |
| 20-800 | 68-1472 | 0.2430 | Holborn and Curtis |
| 0-200 | 32- 392 | 0.2389 | Wiedemann |
|____________|____________|_______________|____________________|
This value is of particular importance in waste heat work and it is
regrettable that there is such a variation in the different experiments.
Mallard and Le Chatelier determined values considerably higher than any
given in Table 28. All things considered in view of the discrepancy of
the values given, there appears to be as much ground for the use of a
constant value for the specific heat of air at any temperature as for a
variable value. Where this value is used throughout this book, it has
been taken as 0.24.
Air may carry a considerable quantity of water vapor, which is
frequently 3 per cent of the total weight. This fact is of importance in
problems relating to heating drying and the compressing of air. Table 29
gives the amount of vapor required to saturate air at different
temperatures, its weight, expansive force, etc., and contains sufficient
information for solving practically all problems of this sort that may
arise.