Search results
Results From The WOW.Com Content Network
For standard solar modules, there is also modeling and experimental evidence that no tracking or cooling modifications are needed if the concentration level is low [38] Low-concentration systems often have a simple booster reflector, which can increase solar electric output by over 30% from that of non-concentrator PV systems.
A solar power tower at Crescent Dunes Solar Energy Project concentrating light via 10,000 mirrored heliostats spanning thirteen million sq ft (1.21 km 2). The three towers of the Ivanpah Solar Power Facility Part of the 354 MW SEGS solar complex in northern San Bernardino County, California Bird's eye view of Khi Solar One, South Africa
Acceptance angle. The "acceptance angle" figure illustrates this concept. The concentrator is a lens with a receiver R.The left section of the figure shows a set of parallel rays incident on the concentrator at an angle α < θ to the optical axis.
The level of soiling in a photovoltaic system can be expressed with the soiling ratio (SR), defined in the technical standard IEC 61724-1 [16] as: S R = Actual power output Expected power output if clean . {\displaystyle SR={\frac {\text{Actual power output}}{\text{Expected power output if clean}}}.}
According to the authors, this ratio is well approximated by ln(fQ s /Q c), where f is the combination of factors f s f ω t s /(2t c), in which f ω is the solid angle of the sun divided by π. The maximum value of f without light concentration (with reflectors for example) is just f ω /2, or 1.09 × 10 −5, according to the authors.
For example, when the sun is more than about 60° above the horizon (<30°) the solar intensity is about 1000 W/m 2 (from equation I.1 as shown in the above table), whereas when the sun is only 15° above the horizon (=75°) the solar intensity is still about 600 W/m 2 or 60% of its maximum level; and at only 5° above the horizon still 27% of ...
The solar "constant" is not a physical constant in the modern CODATA scientific sense; that is, it is not like the Planck constant or the speed of light which are absolutely constant in physics. The solar constant is an average of a varying value. In the past 400 years it has varied less than 0.2 percent. [2]
Normally A increases with Q and S because the higher the water level is the higher the discharge capacity becomes. The factor is therefore called Aq instead of A. The non-linear reservoir has no usable unit hydrograph. During periods without rainfall or recharge, i.e. when R = 0, the runoff equation reduces to Q2 = Q1 exp { − Aq (T2 − T1 ...