Is solar radiation and insolation the same?

Is solar radiation and insolation the same?

Solar radiation is the radiant energy emitted from the sun. Therefore: Irradiance refers to the amount of solar radiation received per unit area by a given surface, expressed in kW/ m². Insolation refers to the quantity of solar radiation energy received on a surface during an amount of time, expressed in kWh/ m².

What does W m 2 mean?

Units. The SI unit of irradiance is watt per square metre (W/m2 = Wm−2). An alternative unit of measure is the Langley (1 thermochemical calorie per square centimeter or 41,840 J/m2) per unit time. The solar energy industry uses watt-hour per square metre (Wh/m2) per unit time.

What is direct normal irradiation?

Direct Normal Irradiation (DNI) is the amount of solar radiation received per unit area by a surface that is always held perpendicular (or normal) to the rays that come in a straight line from the direction of the sun at its current position in the sky.

What does kwh m2 mean?

kW·h/(m2

What is direct and diffuse solar radiation?

Direct radiation also known as “beam radiation” or “direct beam radiation” is used to describe solar radiation travelling on a straight line from the sun down to the surface of the earth. In simple terms, direct radiation has a definite direction but diffuse radiation follows a much more scattered, uncertain path.

What are the direct solar radiation?

The solar radiation that reaches the Earth’s surface without being diffused is called direct beam solar radiation. The sum of the diffuse and direct solar radiation is called global solar radiation. Atmospheric conditions can reduce direct beam radiation by 10% on clear, dry days and by 100% during thick, cloudy days.

How do you calculate diffuse radiation?

A fair estimate of the diffuse irradiance can be obtained by subtracting the direct normal beam radiation projected onto a horizontal surface from the global irradiance.