CEM HVAC Systems & Building Envelope 2

Question 1

What is the primary purpose of an economizer cycle in an HVAC system?

Accepted Answer

Use outdoor air for free cooling when conditions allow

Answer

An economizer uses outdoor air for cooling when outdoor conditions are favorable, reducing or eliminating mechanical cooling energy.

Question 2

A building's R-value measures which property of the building envelope?

Accepted Answer

Thermal resistance to heat flow

Answer

R-value quantifies the thermal resistance of a material or assembly; higher R-values indicate better insulation performance.

Question 3

Which HVAC control strategy staggers equipment startup times to reduce peak electrical demand?

Accepted Answer

Optimal start

Answer

Optimal start calculates the latest possible startup time to reach setpoint by occupancy, spreading equipment activation and reducing demand spikes.

Question 4

In a chilled water system, what does the term 'chiller plant delta-T' refer to?

Accepted Answer

Temperature difference between chilled water supply and return

Answer

Delta-T in a chilled water system is the difference between return and supply water temperatures; a low delta-T syndrome indicates system inefficiency.

Question 5

Which window property most directly controls the amount of solar radiation entering a building?

Accepted Answer

Solar Heat Gain Coefficient (SHGC)

Answer

SHGC indicates the fraction of incident solar radiation admitted through a window; lower values reduce cooling loads in warm climates.

(CEM) Certified Emergency Manager Practice Test

(CEM) Certified Emergency Manager Practice Test

CEM HVAC Systems & Building Envelope 2