# Theory terminology confusion

Solar Expert Posts: 259 ✭✭
Hi guys,

Define basic terminology, including solar radiation, solar irradiance, solar irradiation, solar insolation, solar constant, air mass, ecliptic plane, equatorial plane, pyrometer, solar declination, solstice, equinox, solar time, solar altitude angle, solar azimuth angle, solar window, array tilt angle, array azimuth angle, and solar incidence angle.

And its the first 4 terms Im confused about. This is what I currently think:

Solar Radiation: I guess it just means the scientific term about the energy put out by the sun being called Solar Radiation, the spectrum of visible and invisible light.

Solar Irradiance: The amount of power (rate) falling on the earth surface at a given moment ~ 1000 W/m2

Solar Insolation: The amount of energy (amount) fallen on the earth surface during a certain amount of time ~ 6000W-hrs/m2-day

• Solar Expert Posts: 230 ✭✭
Re: Theory terminology confusion

I would go with 'solar irradiation' simply being a synonym for 'solar insolation', which you have defined correctly. A trick question of sorts, I think.
• Solar Expert Posts: 2,397 ✭✭✭✭
Re: Theory terminology confusion
Insolation (short for incident or incoming solar radiation) is a measure of solar radiation energy received on a given surface area and recorded during a given time. It is also called solar irradiation and expressed as "hourly irradiation" if recorded during an hour or "daily irradiation" if recorded during a day. The unit recommended by the World Meteorological Organization is megajoules per square metre (MJ/m2) or joules per square millimetre (J/mm2).[1] An alternate unit of measure is the Langley (1 thermochemical calorie per square centimeter or 41,840 J/m2). Practitioners in the business of solar energy may use the unit watt-hours per square metre (Wh/m2). If this energy is divided by the recording time in hours, it is then a density of power called irradiance, expressed in watts per square metre (W/m2).

http://en.wikipedia.org/wiki/Insolation

Me likes the bright red where I live :D:D: