Building Engineering Mechanical Engineering 2

Question 1

What is the primary purpose of a cooling tower in a building's HVAC system?

Accepted Answer

To reject heat from the condenser water loop to the atmosphere

Answer

Cooling towers dissipate heat from condenser water by evaporating a small portion of the water into the airstream, rejecting heat to the atmosphere.

Question 2

Which pipe insulation parameter directly limits the rate of condensation on cold water lines?

Accepted Answer

Vapor retarder perm rating

Answer

A low-perm vapor retarder on insulation prevents moist air from migrating to the cold pipe surface where it would condense.

Question 3

A VFD (Variable Frequency Drive) on a pump motor reduces the pump speed to 80% of design. By what factor does the pump's power consumption change according to the affinity laws?

Accepted Answer

0.51 (cube reduction)

Answer

The affinity laws state that pump power varies as the cube of the speed ratio, so 0.8³ ≈ 0.51, meaning power drops to about 51% of design.

Question 4

In a forced-air duct system, static regain design attempts to maintain constant what at each branch takeoff?

Accepted Answer

Total static pressure

Answer

Static regain design sizes downstream ducts so velocity reduction converts kinetic energy back to static pressure, keeping static pressure roughly equal at each takeoff.

Question 5

What ASHRAE standard primarily governs acceptable indoor air quality and minimum ventilation rates for commercial buildings?

Accepted Answer

ASHRAE 62.1

Answer

ASHRAE 62.1 sets minimum ventilation rates and IAQ requirements for commercial and institutional buildings.

Building Engineering Practice Test

Building Engineering Practice Test

Building Engineering Mechanical Engineering 2