FREE CEM Test HVAC Systems & Building Envelope Questions and Answers

Question 1

An energy manager is evaluating the thermal performance of a building's wall assembly.
The wall consists of several layers with a combined thermal resistance (R-value) of 25 hr·ft²·°F/Btu.
What is the overall heat transfer coefficient (U-value) for this wall assembly?

Accepted Answer

0.04 Btu/hr·ft²·°F

Answer

25 Btu/hr·ft²·°F

Answer

0.25 Btu/hr·ft²·°F

Answer

4.0 Btu/hr·ft²·°F

Question 2

A facility's centrifugal chiller is rated at 400 tons and consumes 240 kW at full load. What is the chiller's full-load energy efficiency rating in kW/ton?

Accepted Answer

0.60 kW/ton

Answer

1.67 kW/ton

Answer

0.80 kW/ton

Answer

1.25 kW/ton

Question 3

In a hot, sunny climate, which of the following window properties is most critical for reducing solar heat gain and thus minimizing cooling loads?

Accepted Answer

A low Solar Heat Gain Coefficient (SHGC)

Answer

A high Visible Transmittance (VT)

Answer

A low U-factor

Answer

A high Condensation Resistance (CR)

Question 4

A building's air handling unit (AHU) in a temperate climate is equipped with an air-side economizer. Under which condition should the economizer be fully utilized to provide 'free cooling'?

Accepted Answer

When the outdoor air is cool and dry enough to meet the cooling demand without mechanical refrigeration.

Answer

When the outdoor air enthalpy is higher than the return air enthalpy.

Answer

When the building is unoccupied and the outdoor temperature is below freezing.

Answer

When the outdoor air dry-bulb temperature is 85°F and relative humidity is 90%.

Question 5

What is the primary negative impact of uncontrolled air infiltration on a building's energy consumption in a cold climate?

Accepted Answer

It increases heating loads by allowing cold, unconditioned air to enter the building.

Answer

It increases cooling loads by introducing warm, humid air.

Answer

It improves indoor air quality by introducing fresh air.

Answer

It decreases the effectiveness of radiant heating systems.

Question 6

Which of the following HVAC control strategies directly reduces fan energy consumption in a Variable Air Volume (VAV) system during periods of partial load?

Accepted Answer

Static pressure reset

Answer

Chilled water temperature reset

Answer

Morning warm-up cycle

Answer

Demand-controlled ventilation

An energy manager is evaluating the thermal performance of a building's wall assembly.The wall consists of several layers with a combined thermal resistance (R-value) of 25 hr·ft²·°F/Btu.What is the overall heat transfer coefficient (U-value) for this wall assembly?

An energy manager is evaluating the thermal performance of a building's wall assembly.
The wall consists of several layers with a combined thermal resistance (R-value) of 25 hr·ft²·°F/Btu.
What is the overall heat transfer coefficient (U-value) for this wall assembly?