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

Magnetic declination at the site

Answer

Roof pitch and azimuth simultaneously

Answer

Ground reflectance (albedo) coefficient

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

Soiling loss factor

Answer

Wiring resistance loss

Answer

Spectral correction factor

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

The roof tilt faces 12° off true south

Answer

The site latitude is 12° north of the equator

Answer

The array is tilted 12° from horizontal toward south

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

Winter solstice at solar noon

Answer

Spring equinox at 9 AM

Answer

Fall equinox at 3 PM

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

The minimum GHI required to start the inverter

Answer

The rated capacity of the irradiance sensor used on site

Answer

Maximum irradiance before modules enter thermal derating

Question 6

Which instrument uses a fish-eye lens to photograph the sky dome and then analyzes the image to calculate solar access and shading fractions?

Accepted Answer

HemisView or SunEye device

Answer

Pyranometer

Answer

Pyrheliometer

Answer

Inclinometer

Question 7

A commercial rooftop in Chicago has HVAC units that will shade the southern portion of the proposed array. The BEST design strategy to minimize electrical mismatch losses is to:

Accepted Answer

Orient shaded modules in separate sub-arrays on distinct MPPT inputs

Answer

Use a central inverter and series-connect all modules uniformly

Answer

Increase system voltage by adding more modules in series

Answer

Apply anti-reflective coating to shaded modules only