Certified Energy Auditor HVAC Systems and Performance Questions and Answers

Question 1

What is the primary difference between the SEER (Seasonal Energy Efficiency Ratio) and EER (Energy Efficiency Ratio) ratings for air conditioning systems?

Accepted Answer

EER is calculated at a single set of outdoor and indoor conditions, while SEER represents performance over a typical cooling season with varying temperatures.

Answer

SEER is used for heating performance, while EER is for cooling.

Answer

SEER ratings are only applicable to commercial rooftop units, whereas EER is for residential split systems.

Answer

EER includes the energy consumed by the indoor air handler fan, while SEER does not.

Question 2

An energy auditor is inspecting a rooftop unit (RTU) on a commercial building in a temperate climate. They notice that on a cool, low-humidity day (55°F outside), the RTU's compressor is running to cool the interior space, which is at 74°F. What HVAC component is most likely malfunctioning or improperly controlled?

Accepted Answer

The air-side economizer.

Answer

The condenser fan motor.

Answer

The reversing valve.

Answer

The thermostatic expansion valve (TXV).

Question 3

Which of the following best describes the relationship between fan speed and power consumption in a Variable Air Volume (VAV) system equipped with a Variable Frequency Drive (VFD)?

Accepted Answer

Power consumption is proportional to the cube of the change in fan speed (e.g., a 20% speed reduction yields a ~49% power reduction).

Answer

Power consumption is directly proportional to the change in fan speed (e.g., a 20% speed reduction yields a 20% power reduction).

Answer

Power consumption is proportional to the square of the change in fan speed (e.g., a 20% speed reduction yields a 36% power reduction).

Answer

Power consumption remains constant regardless of fan speed; only airflow changes.

Question 4

An energy auditor is evaluating the performance of a large water-cooled centrifugal chiller. Which of the following metrics is the most common and direct measure of its energy efficiency at full-load conditions?

Accepted Answer

Kilowatts per ton (kW/ton)

Answer

Coefficient of Performance (COP)

Answer

Energy Efficiency Ratio (EER)

Answer

Integrated Part Load Value (IPLV)

Question 5

During a combustion analysis of a natural gas boiler, an energy auditor measures a high stack temperature and a low O₂ (oxygen) reading in the flue gas. What is the most likely cause of this condition?

Accepted Answer

Excessive scale buildup on the water side of the heat exchanger tubes.

Answer

The boiler is cycling on and off too frequently.

Answer

There is too much excess air in the combustion process.

Answer

The fuel-to-air ratio is too rich (insufficient combustion air).

Question 6

Which of the following is a primary energy-saving advantage of a Variable Refrigerant Flow (VRF) system compared to a traditional chilled water system?

Accepted Answer

They can provide simultaneous heating and cooling to different zones and recover heat from one zone to use in another.

Answer

They eliminate the need for any outdoor equipment, reducing heat loss to the environment.

Answer

They use natural gas as the primary energy source, which is typically cheaper than electricity.

Answer

They operate at a much lower refrigerant pressure, significantly reducing the risk of leaks.