Relation between the area of the metal-covered cell and the total area of the cell.

Relation between the radiation absorbed by a surface and the radiation incident on that surface.

Quotient between the "tip" of the simultaneous global demand in a given period and the sum of the "ends" of the individual searches in the same period. The diversity factor is the inverse of the coefficient of simultaneity.

Relation between the duration of the effective sunshine and the duration of the maximum sunshine theoretically possible. Note: The duration of theoretically possible sunshine can be easily calculated or indicated by the meteorological service to a perfectly free place, but it must be corrected for obstruction due to orographic or other obstacles.

Coefficient that characterizes the amount of aerosols (essentially diffusing microparticles) in the vertical of the place. This coefficient allows to calculate the extinction of the direct radiation by diffusion on the aerosols, not only for a specific wavelength, but also for each one of the wavelengths (and therefore for the whole of the solar spectrum) if knowing the law Of the corresponding variation. Note: The ß turbidity coefficient of Angstrõm corresponds to the wavelength of 1 m and is generally between 0,02 (very pure sky) and 0,20 (polluted sky). Other turbidity coefficients are also used (ß from Schuepp, ß from Valko). However, only the influence of aerosols is taken into account in these various coefficients, whereas the extinction of direct radiation also depends heavily on molecular diffusion and absorption of atmospheric gases (ozone, water vapor, etc.).

The coefficient of utilization of a region in a given time interval is the quotient of its producibility by its average productivity, both for that period and for the same hydraulic equipment of the region.

Installation of energy production, where the steam produced is turbine to produce electricity and subsequently used for heating, in industrial activities.

Properties of coal, in particular its agglomeration and expansion capacity, allowing it to be converted into coke, resistant to the conditions of transport and use in the furnaces for which it is intended.

Solid fuel obtained from the coal by pyrolysis in the absence of air.

Coal usable in coke ovens.

Collector usually of concentration in which the void between the absorbent surface and the cover is made.

It consists of reflectors, lenses, optical devices designed to concentrate solar cells that penetrate through the opening of the envelope a focal zone whose surface is smaller than that of the collector opening. Note 1: This type of collector uses essentially direct solar radiation. Note 2: The main types of concentrators used are refraction (lens collectors) and reflectors. Reflective surfaces of the latter may be hemispherical, parabolic, parabolic-cylinder Or conical.

Angle formed by the plane of the collector and the horizontal plane.

Area of the front section of a collector through which direct normal solar radiation can reach the absorbent surface, either directly or by reflection.

Relation between the amount of energy actually taken by a solar collector during a given time interval and the amount of solar energy incident on the collector surface during the same time interval.
Note: In practice, each collecting system has a certain thermal inertia. Therefore, yield measurements are performed based on the measurements taken over a period of time with constant conditions (climatic data, collector temperature)

An electric power plant comprising a gas turbine whose exhaust gas feeds a heat recovery unit in which steam is generated to drive a second turbine.

Exothermic reaction of a fuel with oxygen, which appears spontaneously, once the ignition temperature has been reached.

Thermochemical process for obtaining direct heat.