Solar radiation defined

Not to be confused with insulation, the word insolation (acronym for incoming solar radiation") defines the rate at which direct solar radiation is incident upon a unit horizontal surface at any point on or above the surface of the earth. The unit of insolation is the Langley, named after Samuel Pierpoint Langley (1834-1906). an American astronomer, physicist and pioneer in the utilization of solar energy ... 

Pasquill defined six stabihty classes ranging from highly stable, low-turbulence Class F, to unstable, highly turbulent Class A, and he identified the surfece wind speed, intensity of solar radiation, and nighttime sky cover as being the prime factors controlling atmospheric stabihty. PasquiU then correlated observations of the behavior of plumes in terms of their dispersion with the... 

Specific solar radiation conditions are defined by the air mass (AM) value. The spectral distribution and total flux of radiation outside the Earth s atmosphere, similar to the radiation of a black body of 5,900 K, has been defined as AM-0. The AM-1 and AM-1.5 are defined as the path length of the solar light relative to a vertical position of the Sun above the terrestrial absorber, which is at the equator when the incidence of sunlight is vertical (90°) and 41.8°, respectively. The AM-1.5 conditions are achieved when the solar flux is 982 Wm2. However, for convenience purpose the flux of the standardized AM-1.5 spectrum has been corrected to 1,000 Wm2. 

Wind is the motion of air masses caused by the different thermal conditions that occur over the earth s surface as a result of the transmission of solar radiation. Wind energy is defined as the kinetic energy of the wind converted into mechanical work. This mechanical work can be used to drive an electrical generator for the production of electricity. A machine that performs this conversion is called a wind turbine generator (WTG) and a group of these, including the auxiliary equipment, constitute a WF. 

Euphotic Of the depth zone through which light penetrates. The bottom of the euphotic zone is defined as the depth at which less than 1 percent of the incident solar radiation remains, the rest having been either absorbed or reflected. 

Figure 2, Plots of the efficiencies tje, rjY, rfp, and -qc as a function of the wavelength Xg corresponding to the band gap E. The distributions have been calculated for AM 1.2 solar radiation (taken from distribution T/S of Ref. 6). Curves, E, Y, P, and C are plots of -qEy my VPy rjc as defined in Equations 3,8,12, and 16, respectively. Tfc has been calculated for 0.6, 0.8, and 1.0 eV energy loss, respectively, as...

A common term used to express the path length traversed by solar radiation to reach the earth s surface is the air mass, m, defined as... 

Solar radiation consists of photons of different energies E. Of particular interest is the spectral distribution n(E), which describes how the photons are distributed over the different energy values. The quantity n(E) indicates the number of photons of specific energy E per unit surface area per unit energy per unit time. From this distribution we define the total photon flux as... 

The concentration factor C has been defined as the factor by which the incident solar radiation can be augmented. The ideal concentrator would compensate for the effect of the dilution factor/= 2.16 x 10-5, the value for our planet. The maximum concentration factor therefore is Cmax = 1 /f= 46,300. For an arbitrary value of C, Equation 17.32 has to be adapted according to... 

In dealing with problems of solar radiation, as opposed to blackbody radiation, the effect of the solid angle in which the radiation is confined has been examined (2-4) by considering the volume density of photons to be reduced. Landsberg(6) considers dilute radiation in the sense that the spectral distribution is retained but the radiation density is reduced. This leads to defining the temperature of a spectral component as... 

The photochemical effects of solar irradiation on cellulose products have been ascribed to a complex set of reactions in which both the absorption of light and the presence of oxygen, moisture, and impurities are involved (35,51). Solar radiation usually is defined as an electro-... 

Loon and Duffy, 2000, McCluney, 1994), or sometimes between X of 280 nm and 320 nm (Sonnemann, 1992). Other authors define it between X of 290 nm and 320 nm because no solar radiation between 280 nm and 290 nm can penetrate through the atmosphere to reach the ground level (Moore, 1996). 

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. 

The solar concenfrafion ratio of a solar collector is defined as the ratio of the aperture area of fhe reflector to fhe area of the receiver (Rabl, 1985). This quantity gives an approximation to the number of times the radiative flux density (W m ) is increased in the surface of the receiver, as compared to the incoming solar radiation. The concentration ratio is commonly expressed as a number of suns for insfance, a collector that increases the radiative flux densify five fimes is said to have a five suns concentration ratio. Thus, the formula for the concentration ratio is... 

D65, daylight, with a CCT of 6500K is defined by the CIE. The International Standards Organization Standard ISO 10977 (1993) refers to this fact. D65 is also known as D6500 or Standard Illuminant D by the CIE, represents daylight over the spectral range 300 to 830 nm was first adopted in 1966. This standard is not a particular lamp but an internationally agreed to spectral power distribution for solar radiation, issued by the CIE as "Technical Report, Solar Irradiance," first edition... 

The bio-reactor construction must cover the area (presumably of water, since land use would entail the higher land costs) from which solar radiation is to be collected and must, from a closed construction capable of keeping the hydrogen produced from escaping, pipe it to the shore. The cost can therefore be expected to be similar to that of thermal solar collectors. It follows from the discussion in Chapter 2 that the efficiency defined as the energy value of the hydrogen produced divided by the incoming solar radiation on the reactor surface will be considerably below 1%. Table 6.2 assumes for illustration an efficiency of 0.1% and estimates cost on the basis of the similarity to solar collectors. 

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