Red Rocks Community College

ENY 130Fall 2009

Module 3: Solar Resource

The Solar Resource

Where/when does the sun shine?

Summer Solstice (June 21)

December 21

Longitude and Latitude

Where are we? (March,Sept 21)

Another view…. During Equinox’s

Azimuth / Altitude (height)

Source: NOAA

Solar Path

Window

Sun Path Chart

Determine Your Solar Window

Sun site selector

Solar site selector

Wiley - Asset

Solmetric Sun Eye

A Solar Pathfinder

Using the Pathfinder

Under the dome….

Can also be done wrong

Magnetic Declination

Mag Dec and direction

World Magnetic Declination

Best tilt angle for panels?

Denver Solar Data (Insolation)

Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Avg.

kWh/sq meter/day

5.07 5.54 6.80 6.65 6.69 6.67 6.84 6.66 7.0 6.5 5.0 4.8 6.20

kWh/sq ft / day

.185 .203 .249 .243 .245 .244 .250 .244 .26 .24 .19 .18 .227

Btu / sq ft/ day

1700

Orientation and tilt Efficiency

What are our numbers?

Denver Latitude? Panel tilt for winter gain Panel tilt for year around Panel tilt for summer

Why tilt for summer here in Denver?

Why tilt for electricity in winter?

Watts per square meter

Where does the light go?

Source: NREL

Distance through atmosphere matters

Direct Light vs. Tilt

Insolation

Insolation around the world

Site Assesments Tools for site

evaluation Compass Solar Access finder Digital Camera Tape Measure Protractor Note Pad Ladder Pencil/Pen

Conducting a Site Assessment

Observing proposed panel locations Establish location of electrical

equipment Roof or site orientation Shading problems Conduct solar assessment

(Pathfinder) Fill out form

Using the Solar Pathfinder

Set up in proposed location of panels Orient for true south Level the unit Take digital picture above level bubble

and about 15” above dome (higher with zoom)

Download picture into computer Start Pathfinder software and follow

directions

Using the Pathfinder

Pathfinder results