How to Position Your Solar Energy System for Maximum Output

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Isogonic map of the United States.
Isogonic map of the United States.
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The solar window from above.
The solar window from above.
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The solar window from ground level.
The solar window from ground level.
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Solar Pathfinder
Solar Pathfinder
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Using a Solar Site Selector.
Using a Solar Site Selector.
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Protractor method
Protractor method
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"Solar Water Heating: A Comprehensive Guide to Solar Water and Space Heating Systems" by Bob Ramlow and Benjamin Nusz is an introduction to modern solar energy systems.

Of all the renewable energy options open to us, solar hot water heaters have been around the longest. There are several designs to choose from, and selecting the best solar collector can be confusing.Solar Water Heating: A Comprehensive Guide to Solar Water and Space Heating Systems, by Bob Ramlow and Benjamin Nusz (New Society Publishers, 2010), is the definitive guide to this clean reliable technology. In this excerpt, the authors explain how to site your solar energy system properly by determining the solar window of your location using tools like the Solar Pathfinder and an isogonic chart.

You can purchase this book from the MOTHER EARTH NEWS store: Solar Water Heating.

Siting a Solar Energy System

Sometimes it seems silly to state the obvious, but here goes: solar collectors must be in the full, direct sun if they are going to work properly. This may seem obvious, but you wouldn’t believe how many times we’ve had prospective customers tell us there is lots of sun where they are thinking of placing the solar collectors, only to find the spot in considerable shade. So, what is the bottom line for choosing a location for solar collectors? Read on.

First, let’s review how the sun shines on the Earth. The relative movement of the sun across the sky determines our days as well as our seasons. The path of the sun changes every day. Here in Wisconsin, on the first day of spring (March 21), the sun rises directly in the east; at noon it is directly to the south and is above the horizon at about a 45 degree angle, and it sets almost directly west. On that day, the sun is up for 12 hours and down for 12 hours. On the longest day of the year, the first day of summer (June 21), the sun rises in the northeastern sky, is directly overhead at noon (68 degrees from horizontal) and sets in the northwest. The first day of fall (September 21) is exactly like the first day of spring. The shortest day of the year is the first day of winter (December 21), and the sun rises in the southeastern sky, is directly to the south at noon and is about 23 degrees above horizontal (low in the sky) and then sets in the southwest. The height of the sun, in degrees, will vary depending on your geographical location. The further north you go, the lower the sun will be during the winter months.

  • Published on May 26, 2016
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