Certified Energy Auditor Certification Certified Energy Auditor HVAC Systems and Controls Questions and Answers 2

Question 1

What is the primary advantage of a variable air volume (VAV) system compared to a constant air volume (CAV) system in commercial buildings?

Accepted Answer

Reduced fan energy consumption at partial loads

Answer

Lower initial installation cost

Answer

Simpler maintenance requirements

Answer

Better humidity control at all loads

Question 2

During an energy audit, which measurement is most critical for evaluating the efficiency of a chiller plant?

Accepted Answer

kW per ton of cooling

Answer

Supply air temperature

Answer

Condenser water flow rate

Answer

Refrigerant charge level

Question 3

What does an economizer cycle on a rooftop HVAC unit accomplish?

Accepted Answer

Uses outdoor air for free cooling when conditions permit

Answer

Recovers heat from exhaust air streams

Answer

Reduces refrigerant charge requirements

Answer

Increases compressor efficiency at low ambient temperatures

Question 4

Which control strategy is most effective for reducing energy consumption in a multi-zone HVAC system experiencing simultaneous heating and cooling?

Accepted Answer

Resetting supply air temperature based on zone demands

Answer

Lowering the thermostat setpoint uniformly

Answer

Increasing minimum airflow setpoints

Answer

Adding supplemental electric reheat coils

Question 5

What is the recommended approach when an energy auditor discovers that building static pressure setpoints are significantly higher than necessary?

Accepted Answer

Lower the static pressure setpoint and verify zone comfort is maintained

Answer

Replace the supply fan with a smaller model

Answer

Install additional VAV boxes to reduce duct pressure

Answer

Increase duct insulation to compensate for pressure losses

Question 6

In a direct digital control (DDC) system, what is the function of the proportional-integral (PI) control loop for a cooling coil valve?

Accepted Answer

Modulates the valve position to maintain discharge air temperature at setpoint

Answer

Opens the valve fully whenever cooling is needed

Answer

Cycles the valve between fully open and fully closed at fixed intervals

Answer

Maintains a constant water flow rate regardless of load