NABCEP NABCEP Solar Heating Installation Professional

Question 1

What is the primary difference between a solar thermal collector and a photovoltaic (PV) module?

Accepted Answer

Solar thermal collectors convert sunlight into heat, while PV modules convert sunlight into electricity

Answer

Solar thermal collectors generate electricity directly

Answer

Solar thermal collectors require no maintenance

Answer

PV modules produce more energy per square foot in all climates

Question 2

Which type of solar thermal collector is most efficient in cold climates with high heat demand?

Accepted Answer

Evacuated tube collector

Answer

Unglazed flat-plate collector

Answer

Batch (ICS) collector

Answer

Open-loop thermosiphon collector

Question 3

What is the function of a differential controller in an active solar thermal system?

Accepted Answer

It turns the circulator pump on when the collector is hotter than the storage tank and off when it is not

Answer

It converts DC power to AC for the pump

Answer

It measures solar irradiance only

Answer

It controls the backup electric heater only

Question 4

Which heat transfer fluid is commonly used in closed-loop solar thermal systems to prevent freezing?

Accepted Answer

Propylene glycol-water mixture

Answer

Distilled water only

Answer

Gasoline

Answer

Ammonia

Question 5

What is the purpose of a pressure relief valve in a solar thermal system?

Accepted Answer

To release excess pressure and prevent damage to collectors or storage tanks from thermal expansion

Answer

To regulate pump speed

Answer

To control collector tilt angle

Answer

To measure flow rate

Question 6

What is 'stagnation' in a solar thermal system and why is it a concern?

Accepted Answer

When no fluid flows through the collectors while they are receiving full solar radiation, causing extreme temperatures and potential fluid degradation

Answer

When the pump runs continuously without stopping

Answer

When collectors are shaded for extended periods

Answer

When the storage tank is fully charged