How to Site Active Solar Collectors & Flat Plate Modules

Calculate true south. A compass will give you an initial reading, but take into account that Earth's magnetic field can cause a deviation of up to 22 degrees from true south in some parts of the country. To get a more exact calculation, visit the installation site at solar noon on a sunny day and mark the shadow direction. You can calculate the solar noon in your specific area by finding out the time of sunrise and sunset and working out the midpoint.

Analyze whether any obstructions --- from buildings and trees, for example --- to the south will stop your solar collector from accessing the sun during some or all of the year. It is essential for the efficiency of your collector that it is unobstructed by shading from 9 a.m. to 3 p.m., otherwise as the "solar window."

Calculate the optimal tilting angle of your solar collector to maximize its efficiency in capturing the sunlight. The ideal position of your solar collector would be one that receives the sun's rays at right angles; however, practicability dictates that you will angle your collector away from this location. It is very important at this point to work out the latitude of your installation site. The latitude of a location on the Earth is the angular distance of that location south or north of the Equator.

For the most beneficial results, especially when installing a domestic water heating application, tilt a fixed solar collector at an angle equal to the latitude of the location. This will ensure the collector is directly pointed towards the sun in the spring and fall. Although the sunlight during other times of the year will not be collected as efficiently, overall the yearly intake is maximized.

Make the following adjustments to the tilt angle for the following solar collector applications. For space heating only, or combined space and water heating, add 15 degrees to the latitude so that the collector directly faces the low winter sun, to ensure efficiency in the cold winter months.