Chapter 8 REVIEW Solar Site Analysis and Mounting

Question 1

The array tilt angle

Answer 1

The array tilt angle is a solar array’s inclination as measured in degrees from horizonal. Modules collect the most solar radiation when they are angled perpendicular to the sun.

Question 2

Magnetic declination

Answer 2

Magnetic declination is the difference ( in degrees to the east or west ) between magnetic compass north and true north.

Question 3

An inclinometer

Answer 3

An inclinometer is a device used to measure slope or tilt angle.

Question 4

A solar window

Answer 4

A solar window is the timeframe during which a solar system site is free of shade.

Question 5

Irradiance

Answer 5

Irradiance is the intensity ( or power) of sunlight, measured in watts per square meter (W/m”). Power is an instantaneous value, so irradiance is the particular sunlight intensity at any given moment. Irradiance changes constantly throughout the day due to changes in the atmosphere and the sun’s angle.

Question 6

Insolation

Answer 6

Insolation, also known as irradiation, is an amount of solar radiation energy on a surface over a
period of time, measured in watt-hours (or kilowatt-hours) per square meter (Wh/m2 or kWh/m2).
Energy is power over time, so insolation is cumulative irradiance over a given time.

Question 7

Peak sun hours

Answer 7

Peak sun hours are a measure of insolation. One peak sun hour is the equivalent amount of time during which irradiance averages 1,000 W/m² (or 1 kW/m²). Because it is based on amount of time (for example a day, month, or year), it is the daily, monthly, or annual insolation received by a surface given a specific location, tilt angle, and orientation.

Question 8

Full sun

Answer 8

Full sun is equivalent to a peak sun hour or 1,000 watts per square meter for one hour.

Question 9

Solar azimuth angle

Answer 9

The horizontal aspect of the sun’s position relative to a defined direction is called its solar azimuth angle.

Question 10

True south

Answer 10

True south is geographic south, as opposed to magnetic south.

Question 11

Altitude angle

Answer 11

The altitude angle is the sun’s height above the horizon measured in degrees. The altitude angle value increases as the sun rises above the horizon. ( 0 degrees would be the sunrise, and 90 degrees would be directly overhead.)

Question 12

Solar noon

Answer 12

Solar noon refers to the time when the sun is its highest altitude angle for the day, and the solar azimuth angle is 180 degrees (true south)

Question 13

Sun charts

Answer 13

Sun charts are available for different latitude and depict the sun’s path ( altitude and azimuth angles) across the sky at any time of day and any time of year. Many site evaluation tools use sun charts to predict shading for a site