Solar radiation characteristics

Sivkov, S.I. (1971) Computation of Solar Radiation Characteristics, Israel Program for Scientific Translation, Jerusalem. 

The organic chemical industry, the food processing industry, the pulp and paper industry, the textile industry, and the petroleum industry are important industries that produce organic process wastes. Unlike inorganic process wastes, they contain dissolved and insoluble matter in the main wastewater stream thus, they are more difficult to handle for disposal. They have its characteristic biological problems and spontaneous interaction with the surrounding environment, particularly, under high solar radiation. 

Fig. 13.1 Spectral characteristics of the solar radiation at the top of the atmosphere and after passing through the atmosphere to sea level...

The necessary starting point for any study of the chemistry of a planetary atmosphere is the dissociation of molecules, which results from the absorption of solar ultraviolet radiation. This atmospheric chemistry must take into account not only the general characteristics of the atmosphere (constitution), but also its particular chemical constituents (composition). The absorption of solar radiation can be attributed to carbon dioxide (C02) for Mars and Venus, to molecular oxygen (02) for the Earth, and to methane (CH4) and ammonia (NH3) for Jupiter and the outer planets. 

Ozone forms in the upper stratosphere from molecular oxygen under the influence of UV solar radiation. In the lower stratosphere and troposphere, the source of ozone is the decomposition of nitrogen dioxide under the influence of UV and visible radiation. The formation of the vertical profile of ozone concentration is connected with its meridional and vertical transport. The general characteristic of this profile is the total amount of ozone measured by the thickness of its layer given in Dobson units (1 DU = 0.001 cm). 

ADEOS An improved, satellite Earth-observing system equipped with modernized radiometer of the visible and near-IR intervals (AYNIR), ocean color and temperature scanner (OCTS), and radiometer POLDER to carry out global systematic measurements of polarization and spectral characteristics of solar radiation reflected by the Earth-atmosphere system. The satellite ADEOS-2/ Midori-2 was launched on December 14, 2002 by the Japan Space Agency and is an ideal means of global monitoring. 

After the introduction, we will briefly discuss the main characteristics of solar radiation. Consistent with the scientific principles on which this book is founded, a rigorous thermodynamic analysis will then follow of the creation of wind energy, of photothermal and photovoltaic energy conversion, and of photosynthesis. Most of this chapter has been based on the monograph Thermodynamics of Solar Energy Conversion by De Vos [1]. 

This should have summed up the major characteristics of solar radiation that are relevant for the context of this book. For further details the interested reader is referred to the monograph by De Vos [1] on which, as has been mentioned in the beginning, most of the material presented above has been based. 

Applying the same procedure for determining the maximum power characteristics as before and assuming moderately concentrated sunlight for which C = 389 [1], the solar energy efficiency w increases from 13% to somewhat above 60%. For the limit case of C = Cmax—all solar radiation is captured by our planet—w is close to 85%. 

Liu Byh, Jordan R. C., The interrelationship and characteristic distribution of direct, diffuse and total solar radiation. Solar Energy 1960 4 1-9. 

A second characteristic of UV solar radiation is fhat, even for very clear afmospheres, if is composed in similar amounfs of both beam and diffuse radiation (Hulstrom et al., 1985). The first is defined as the radiation arriving directly from the sun, while the second is the solar radiation that has been scattered by gases and aerosols after entering the earth s atmosphere. This second t)/pe of radiafion reaches fhe ground in a more or less diffuse manner that is, with similar intensity from all directions in the sky. In this respect, the situation encountered in solar photocatalytic reactors is quite different from fhe one encounfered in solar fhermal collectors. The latter are able to use the whole solar spectrum, and in that case diffuse radiation accounts for a much smaller fraction of fhe global irradiance. 

Table 14.1 Characteristics of solar radiation striking the earth s surface...

Since however a large fraction of the scattering is in the forward direction, the depletion of solar radiation reaching the ground is not as large as expected merely on the basis of extinction. In addition the presence of the absorbing aerosol modifies the infrared characteristics of the atmosphere. The net effect depends on the size and refractive index of the particles. 

Notice that the absorptivity of aluminum increases with the source temperature, a characteristic for metals, and the absorptivity of electric nonconductors, in general, decreases with temperature. This decrease is most pronounced for surfaces that appear white to the eye. For example, the absorptivity of a white painted surface is low for solar radiation, hut it is rather high for infrared radiation. 

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