Search results
Results from the WOW.Com Content Network
Solar radiation maps are built using databases derived from satellite imagery, as for example using visible images from Meteosat Prime satellite. A method is applied to the images to determine solar radiation. One well validated satellite-to-irradiance model is the SUNY model. [40] The accuracy of this model is well evaluated.
The solar constant includes radiation over the entire electromagnetic spectrum. It is measured by satellite as being 1.361 kilo watts per square meter (kW/m 2) at solar minimum (the time in the 11-year solar cycle when the number of sunspots is minimal) and approximately 0.1% greater (roughly 1.362 kW/m 2) at solar maximum. [1]
Sol-air temperature (T sol-air) is a variable used to calculate cooling load of a building and determine the total heat gain through exterior surfaces. It is an improvement over: = Where: = rate of heat transfer [W] = heat transfer surface area [m 2]
The intensity of electromagnetic radiation can be expressed in W/m 2. An example of such a quantity is the solar constant . Wind turbines are often compared using a specific power measuring watts per square meter of turbine disk area, which is π r 2 {\displaystyle \pi r^{2}} , where r is the length of a blade.
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 ...
Radiative forcing is defined in the IPCC Sixth Assessment Report as follows: "The change in the net, downward minus upward, radiative flux (expressed in W/m 2) due to a change in an external driver of climate change, such as a change in the concentration of carbon dioxide (CO 2), the concentration of volcanic aerosols or the output of the Sun." [3]: 2245
watt per steradian: W/sr: M⋅L 2 ⋅T −3: Radiant flux emitted, reflected, transmitted or received, per unit solid angle. This is a directional quantity. Spectral intensity: I e,Ω,ν [nb 3] watt per steradian per hertz W⋅sr −1 ⋅Hz −1: M⋅L 2 ⋅T −2: Radiant intensity per unit frequency or wavelength. The latter is commonly ...
Direct insolation is measured in (W/m 2) or kilowatt-hours per square meter per day (kW·h/(m 2 ·day)). 1 kW·h/(m 2 ·day) = 1,000 W · 1 hour / ( 1 m 2 · 24 hours) = 41.67 W/m 2 In the case of photovoltaics, average direct insolation is commonly measured in terms of peak direct insolation as kWh/(kWp·y) (kilowatt hours per year per ...