What is one peak sun hour?
- 1 kWh of solar energy per square metre
- One hour of daylight between sunrise and sunset
- One hour during which the sun is directly overhead
- 1 kW of solar power per square metre
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A. 1 kWh of solar energy per square metre
A peak sun hour is an amount of energy: the equivalent of 1,000 W/m² for one hour, or 1 kWh/m². It is not simply an hour of daylight, since morning and evening hours deliver far less than 1,000 W/m².
Reference: Solar resource: peak sun hours
On site drawings an array's azimuth is given as 180 degrees. Which way does the array face?
- North
- East
- South
- West
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C. South
Azimuth is measured clockwise from north: 0° north, 90° east, 180° south, 270° west. Reading 180° as north confuses the reference direction with the half-turn away from it.
Reference: Solar resource: azimuth angle
As a rule of thumb, what fixed tilt angle gives close to the most annual energy from a south-facing array?
- A tilt of 90 degrees in every location
- A tilt about equal to the site latitude
- A completely flat mounting at zero degrees
- A tilt equal to twice the site latitude
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B. A tilt about equal to the site latitude
Tilting the array at roughly the latitude angle points it near the sun's average noon position over the year. A vertical array favours only low winter sun and loses heavily in summer.
Reference: Solar resource: tilt angle and latitude