NABCEP Solar Heating Installer
Certification Practice Exam 100
Questions And Correct Answers
(Verified Answers) Plus Rationales
2026 Q&A Instant Download Pdf
1. What is the primary function of a solar thermal collector?
A. Store energy for later use
B. Convert sunlight directly into electricity
C. Absorb sunlight to heat a fluid
D. Reflect sunlight to generate power
Rationale: Solar thermal collectors capture solar radiation and transfer it to a
working fluid for heating purposes.
2. What is the primary working fluid in most residential solar water heating
systems?
A. Air
B. Water or water-glycol mixture
C. Oil
D. Steam
Rationale: Water or a water-glycol mixture is commonly used due to its high
heat capacity and freeze protection.
3. Which type of solar collector is best for high-temperature industrial
applications?
A. Flat-plate collector
B. Evacuated-tube collector
,C. Unglazed collector
D. Thermosiphon collector
Rationale: Evacuated-tube collectors have better insulation and efficiency at
high temperatures.
4. What is the function of a heat exchanger in a solar thermal system?
A. Store heat
B. Transfer heat from the solar fluid to potable water
C. Increase fluid flow rate
D. Reduce system pressure
Rationale: Heat exchangers allow the heat collected in the solar loop to safely
transfer to the domestic water supply.
5. In a solar water heating system, what is the purpose of an expansion tank?
A. Generate electricity
B. Filter water
C. Absorb pressure changes due to thermal expansion
D. Store solar fluid
Rationale: Solar fluid expands when heated; the expansion tank prevents
excessive pressure.
6. Which of the following is a key advantage of a thermosiphon system?
A. Requires pumps
B. Operates without pumps due to natural convection
C. High maintenance cost
D. Only works with glycol fluids
Rationale: Thermosiphon systems rely on natural circulation to move heated
fluid, simplifying design and operation.
7. What is the typical stagnation temperature of a flat-plate solar collector?
A. 50–100°C
B. 150–200°C
C. 250–300°C
D. 400–450°C
, Rationale: Stagnation temperature is the maximum temperature a collector
can reach under no-flow conditions; flat-plate collectors usually reach 150–
200°C.
8. Which type of solar water heating system is most suitable for cold climates
with freezing conditions?
A. Direct (open-loop) system
B. Indirect (closed-loop) system with antifreeze
C. Unglazed collector system
D. Thermosiphon with potable water
Rationale: Indirect systems prevent freezing by circulating an antifreeze
solution through the collector.
9. What is the primary reason for inclining a solar collector?
A. Reduce collector weight
B. Maximize solar radiation absorption
C. Improve fluid flow
D. Prevent leaks
Rationale: The angle of inclination is optimized based on latitude to maximize
yearly solar gain.
10. Which of the following instruments is most commonly used to measure
solar irradiance on a collector?
A. Hygrometer
B. Barometer
C. Pyranometer
D. Thermocouple
Rationale: Pyranometers measure solar radiation incident on a surface,
critical for system performance evaluation.
11. In a forced circulation solar water heating system, what component
ensures fluid movement?
A. Heat exchanger
B. Thermosiphon
Certification Practice Exam 100
Questions And Correct Answers
(Verified Answers) Plus Rationales
2026 Q&A Instant Download Pdf
1. What is the primary function of a solar thermal collector?
A. Store energy for later use
B. Convert sunlight directly into electricity
C. Absorb sunlight to heat a fluid
D. Reflect sunlight to generate power
Rationale: Solar thermal collectors capture solar radiation and transfer it to a
working fluid for heating purposes.
2. What is the primary working fluid in most residential solar water heating
systems?
A. Air
B. Water or water-glycol mixture
C. Oil
D. Steam
Rationale: Water or a water-glycol mixture is commonly used due to its high
heat capacity and freeze protection.
3. Which type of solar collector is best for high-temperature industrial
applications?
A. Flat-plate collector
B. Evacuated-tube collector
,C. Unglazed collector
D. Thermosiphon collector
Rationale: Evacuated-tube collectors have better insulation and efficiency at
high temperatures.
4. What is the function of a heat exchanger in a solar thermal system?
A. Store heat
B. Transfer heat from the solar fluid to potable water
C. Increase fluid flow rate
D. Reduce system pressure
Rationale: Heat exchangers allow the heat collected in the solar loop to safely
transfer to the domestic water supply.
5. In a solar water heating system, what is the purpose of an expansion tank?
A. Generate electricity
B. Filter water
C. Absorb pressure changes due to thermal expansion
D. Store solar fluid
Rationale: Solar fluid expands when heated; the expansion tank prevents
excessive pressure.
6. Which of the following is a key advantage of a thermosiphon system?
A. Requires pumps
B. Operates without pumps due to natural convection
C. High maintenance cost
D. Only works with glycol fluids
Rationale: Thermosiphon systems rely on natural circulation to move heated
fluid, simplifying design and operation.
7. What is the typical stagnation temperature of a flat-plate solar collector?
A. 50–100°C
B. 150–200°C
C. 250–300°C
D. 400–450°C
, Rationale: Stagnation temperature is the maximum temperature a collector
can reach under no-flow conditions; flat-plate collectors usually reach 150–
200°C.
8. Which type of solar water heating system is most suitable for cold climates
with freezing conditions?
A. Direct (open-loop) system
B. Indirect (closed-loop) system with antifreeze
C. Unglazed collector system
D. Thermosiphon with potable water
Rationale: Indirect systems prevent freezing by circulating an antifreeze
solution through the collector.
9. What is the primary reason for inclining a solar collector?
A. Reduce collector weight
B. Maximize solar radiation absorption
C. Improve fluid flow
D. Prevent leaks
Rationale: The angle of inclination is optimized based on latitude to maximize
yearly solar gain.
10. Which of the following instruments is most commonly used to measure
solar irradiance on a collector?
A. Hygrometer
B. Barometer
C. Pyranometer
D. Thermocouple
Rationale: Pyranometers measure solar radiation incident on a surface,
critical for system performance evaluation.
11. In a forced circulation solar water heating system, what component
ensures fluid movement?
A. Heat exchanger
B. Thermosiphon
