Exergy analysis of solar radiation processes - Solar Energy Sciences and Engineering Applications - page 29

Figure 2.2.7 Radiation of water vapor layer of thickness 1.04m at temperature 473.15 K and pressure
0.1MPa (from Jacob, 1957).

Table 2.2.1 Radiation data for water vapor layer of thickness 1.04m at temperature 473.15 K and
pressure 0.1MPa.

i 0 , λ × 10 − 6 L 0 , λ × 10 − 4

λ λ

i 0 , λ × λ L 0 , λ × λ

Successive
rectangle
number

W
m 3 sr

W
m 2 Ksr

µ m

1
2
3
4
5
6
7

2.69
6.15
7.95
9.8
14.8
21.0
26.8

0.66
2.8
0.8
2.9
7.1
5.3
6.3

5.0
45.7
17.2
3.7
6.4
5.1
2.2

3.3
128.0
13.8
10.7
45.4
27.0
13.9

1.07
11.72
5.41
1.56
2.38
1.83
0.78

0.0071
0.3282
0.0433
0.0452
0.1690
0.0970
0.0491

Total 242.1 - 0.7389

For the assumed temperature T 0 = 300 K formula (2.2.64) yields:

10 − 8

5 . 6693 ×

300 4 10 − 3 b = + 2 π × 0 . 2421 − 2 π × 300 × 0 . 7389 ×

3

0 . 281 kW / m 2 = 0 . 153 + 1 . 521 − 1 . 393 =

The ratio of the exergy of radiation of the vapor to its energy emission is ψ wv =

b/e = 0 . 281 / 1 . 521 = 0 . 185. More details of the considered example are discussed by

Petela (1961a).