NABCEP NABCEP Solar Heating Installation Professional 3

Question 1

What is a thermosiphon solar water heating system and where is it commonly used?

Accepted Answer

A passive system where natural convection circulates fluid; common in mild climates with no freeze risk

Answer

Thermosiphon systems use natural convection — hot fluid rises into the storage tank above the collectors — eliminating pumps and controls; they are used in warm, freeze-free climates.

Question 2

Which building code section requires solar water heating systems to be installed with a means of preventing scalding from excessively hot water?

Accepted Answer

UPC/IPC Plumbing Code sections requiring a tempering or mixing valve on solar water heaters

Answer

Uniform Plumbing Code and International Plumbing Code require a thermostatic mixing (tempering) valve on solar water heaters because solar storage tanks are often set above 140°F to prevent Legionella.

Question 3

What is the purpose of a check valve in an active solar thermal system's piping loop?

Accepted Answer

To prevent reverse thermosiphoning at night that would lose heat from the storage tank to the cold collectors

Answer

At night, cooled fluid in collectors can sink and pull warm fluid from the storage tank upward through the collectors, losing stored heat; a check valve prevents this reverse flow.

Question 4

Which installation orientation and tilt maximizes annual solar thermal energy collection in the continental US?

Accepted Answer

True south at a tilt angle approximately equal to the local latitude

Answer

Facing collectors true south and tilting them at the local latitude angle maximizes annual solar irradiance interception across all seasons in the Northern Hemisphere.

Question 5

What is the primary advantage of a closed-loop solar thermal system over an open-loop system?

Accepted Answer

It protects the collector loop from freezing and corrosion while keeping potable water separate

Answer

Closed-loop systems use antifreeze in a separate loop, providing freeze protection and preventing mineral scale buildup in expensive collectors while maintaining potable water purity.

NABCEP - North American Board of Certified Energy Practitioners Practice Test

NABCEP - North American Board of Certified Energy Practitioners Practice Test

NABCEP NABCEP Solar Heating Installation Professional 3