Peak Sun Hours Calculator

About the Peak Sun Hours Calculator

Converts daily solar irradiance (Wh/m²/day) into peak sun hours, the equivalent hours of full 1000 W/m² sunshine used in solar sizing.

How to use this calculator

1. Enter the daily irradiance in \(Wh/m^2\).
2. Use the calculator to divide that value by \(1000\).
3. Read the result as peak sun hours, in \(h\).
4. Use the value to compare solar potential or estimate output from a solar system.

The formula explained

The formula computes peak sun hours, which is a standardized way to express solar energy received over a day. It converts daily irradiance into an equivalent number of hours at \(1000\\,Wh/m^2\).

• PSH = peak sun hours, measured in \(h\)
• daily irradiance = total solar energy received in a day, measured in \(Wh/m^2\)

Step by step method

1. Start with the daily irradiance in \(Wh/m^2\).
2. Divide that number by \(1000\) because \(1000\\,Wh/m^2\) is the standard reference level.
3. The quotient is the peak sun hours value.

Worked example

Problem. A site receives \(5200\\,Wh/m^2\) of daily irradiance. What are the peak sun hours?

1. Use the formula \(PSH = \frac{daily\ irradiance\,(Wh/m^2)}{1000}\).
2. Substitute the value: \(PSH = \frac{5200}{1000} = 5.2\).
3. So the site has \(5.2\) peak sun hours.

Tips and common mistakes

• Make sure the irradiance is a daily total in \(Wh/m^2\), not a power reading in \(W/m^2\).
• If you are given \(kWh/m^2\), convert it carefully first, since \(1\\,kWh/m^2 = 1000\\,Wh/m^2\).

Frequently asked questions