Certified Energy Auditor Certification HVAC Systems and Controls 3

Question 1

Demand-controlled ventilation (DCV) uses which sensor to modulate outdoor air intake?

Accepted Answer

CO₂ sensor

Answer

DCV uses CO₂ sensors as a proxy for occupancy; when CO₂ rises above setpoint, outdoor airflow increases to dilute occupant-generated contaminants.

Question 2

What is the purpose of a bypass factor in coil selection?

Accepted Answer

Fraction of air that bypasses the coil without being conditioned

Answer

The bypass factor represents the fraction of air that passes through a cooling coil without contacting the coil surface and therefore is not fully conditioned.

Question 3

A two-pipe hydronic system serving both heating and cooling has what significant limitation?

Accepted Answer

Cannot serve heating and cooling simultaneously in different zones

Answer

A two-pipe system uses the same piping for hot or chilled water, so it can only provide one mode at a time — a problem in buildings with simultaneous heating and cooling needs.

Question 4

What does the term 'integrated part-load value' (IPLV) measure for chillers?

Accepted Answer

Weighted average efficiency at multiple part-load conditions

Answer

IPLV is a weighted average efficiency metric that accounts for part-load operation at 25%, 50%, 75%, and 100% loads, reflecting real-world performance better than full-load ratings.

Question 5

Which type of expansion device provides the best refrigeration system efficiency at varying loads?

Accepted Answer

Electronic expansion valve (EEV)

Answer

Electronic expansion valves precisely modulate refrigerant flow based on superheat and other inputs, providing superior efficiency across all load conditions.

Certified Energy Auditor Certification Practice Test

Certified Energy Auditor Certification Practice Test

Certified Energy Auditor Certification HVAC Systems and Controls 3