NABCEP Solar Site and Shading Analysis 2

Question 1

A Solar Pathfinder instrument is used at a proposed installation site. What does it primarily measure?

Accepted Answer

Percentage of annual solar access blocked by obstructions

Answer

The Solar Pathfinder captures a panoramic reflection of surrounding obstructions and overlays a sun path diagram to quantify the percentage of annual solar energy available at that location.

Question 2

Which shading loss factor specifically accounts for the electrical mismatch caused when one module in a string is partially shaded while others remain unshaded?

Accepted Answer

String mismatch loss

Answer

String mismatch loss occurs because a shaded module forces its series-connected string partners to operate below their maximum power points, reducing total string output disproportionately.

Question 3

When performing a shading analysis using simulation software, a designer enters a 'horizon elevation angle' of 12° at azimuth 180°. What does this mean?

Accepted Answer

An obstruction 12° above the horizon blocks sun at due south

Answer

A horizon elevation angle of 12° at azimuth 180° means that an obstruction (such as a hill or building) rises 12° above the horizontal plane when looking due south from the site.

Question 4

A site in Phoenix, AZ (latitude ~33°N) has a tree located 10 feet north of the array. At what time of year is this tree LEAST likely to cause shading on the array?

Accepted Answer

Summer solstice at solar noon

Answer

At summer solstice, the sun reaches its highest elevation angle of the year (approximately 80° in Phoenix), so a tree directly north casts minimal shadow southward onto the array.

Question 5

The 'irradiance threshold' parameter in PVsyst's shading loss calculation refers to:

Accepted Answer

The plane-of-array irradiance level below which shading losses are ignored in the model

Answer

PVsyst's irradiance threshold sets the POA irradiance level below which detailed shading calculations are skipped, as low-light periods have negligible energy contribution.

(NABCEP) Certified North American Board of Certified Energy Practitioners Specialist Practice Test

(NABCEP) Certified North American Board of Certified Energy Practitioners Specialist Practice Test

NABCEP Solar Site and Shading Analysis 2