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The solar energy to electrical power conversion efficiency is the product of several factors: the fraction of solar energy captured (accounting for optical losses in the solar concentration system), the heating efficiency (accounting for thermal losses in the element receiving the solar energy), and the thermal conversion efficiency (the ...
The soiling ratio is estimated by the ratio of the power output of the soiled device to its expected power output if it was clean. The expected power output is calculated using calibration values and the measured short-circuit current of the clean device. This setup is also referred to as a "soiling measurement station", or just "soiling station".
An example of a Low Concentration PV Cell's surface, showing the glass lensing. Low concentration PV are systems with a solar concentration of 2–100 suns. [37] For economic reasons, conventional or modified silicon solar cells are typically used. The heat flux is typically low enough that the cells do not need to be actively cooled.
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.
where solar intensity external to the Earth's atmosphere = 1.353 kW/m 2, and the factor of 1.1 is derived assuming that the diffuse component is 10% of the direct component. [13] This formula fits comfortably within the mid-range of the expected pollution-based variability:
Bioconcentration can be described by a bioconcentration factor (BCF), which is the ratio of the chemical concentration in an organism or biota to the concentration in water: [2] B C F = C o n c e n t r a t i o n B i o t a C o n c e n t r a t i o n W a t e r {\displaystyle BCF={\frac {Concentration_{Biota}}{Concentration_{Water}}}} [ 2 ]
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.
The Streeter–Phelps equation is used in the study of water pollution as a water quality modelling tool. The model describes how dissolved oxygen (DO) decreases in a river or stream along a certain distance by degradation of biochemical oxygen demand (BOD).