Certified Energy Auditor Certification Certified Energy Auditor HVAC Systems and Performance Questions and Answers 3

Question 1

In a variable air volume (VAV) system, what is the primary energy-saving mechanism compared to a constant volume system?

Accepted Answer

It reduces fan speed and airflow to match actual zone loads

Answer

It uses a higher efficiency compressor

Answer

It switches between heating and cooling coils automatically

Answer

It recirculates return air without conditioning

Question 2

An energy auditor measures a 20°F temperature difference across the supply and return of a chilled water coil. If the design delta-T is 12°F, what does this suggest?

Accepted Answer

The chilled water flow rate is lower than design, causing excessive temperature drop

Answer

The chiller is operating below its rated capacity

Answer

The cooling tower is rejecting too much heat

Answer

The building load exceeds the system design capacity

Question 3

What is the most energy-efficient method to control humidity in a commercial building that currently overcools and reheats air?

Accepted Answer

Install a dedicated outdoor air system (DOAS) with energy recovery

Answer

Add electric resistance reheat coils at each zone

Answer

Lower the chilled water supply temperature

Answer

Increase the minimum outdoor air damper position

Question 4

Which measurement would best help an energy auditor identify duct leakage in a commercial HVAC system?

Accepted Answer

Comparing supply air CFM at the air handler to total CFM measured at all diffusers

Answer

Measuring the refrigerant subcooling at the condenser

Answer

Recording the thermostat setpoint versus actual room temperature

Answer

Checking the voltage at the air handler disconnect

Question 5

What does an EER rating measure for HVAC cooling equipment that differs from SEER?

Accepted Answer

EER measures efficiency at a single peak outdoor temperature condition rather than across a full season

Answer

EER measures heating efficiency while SEER measures cooling efficiency

Answer

EER accounts for part-load performance while SEER does not

Answer

EER is used only for geothermal heat pumps

Question 6

During an energy audit of a large commercial building, the auditor notices the chiller plant operates two 200-ton chillers at 50% load each instead of one chiller at full load. What is the likely energy impact?

Accepted Answer

Most modern chillers are more efficient at part load, so this staging may be acceptable or beneficial

Answer

Running two chillers at part load is always less efficient than one at full load

Answer

Running two chillers doubles the energy consumption regardless of load

Answer

Part-load operation has no effect on chiller efficiency