Sun as an Energy Source

Lecture 8Sun as an Energy Source

E-101 - Energy and Sustainability Professor Lonnie Gamble

Sustainable Living Department Maharishi University of Management

This presentation was prepared on solar powered computers

What Causes Seasons?

What Causes Variations in Day Length?

Photo of sun rising at road

Sun angle with the season

Orientation

Thermal Gains by Window Orientation

Btus / Square Foot Glass/Day - 320 Latitude North

2030 NOW

CASE STUDY

The Nature of Sunlight - Sunlight Density

One sunbeam one mile wide shines on the ground at a 90° angle, and another at a 30° angle. The one at a shallower angle covers twice as much area with the same amount of light energy.

For Max Summer gain:Latitude -15

For max winter gain:Latitude +15

Rule of Thumb:PV = LatitutdeHot Water = Lat+15

If in doubt: Latitude

Use of PV Wattshttp://pvwatts.nrel.gov/version_5.php