HVAC System Design 3

Question 1

Which factor does NOT directly affect the heat loss calculation through a wall assembly?

Accepted Answer

Color of the interior paint

Answer

Heat loss Q = U × A × ΔT; interior paint color has no significant effect on conductive heat loss through a wall.

Question 2

In a constant-air-volume (CAV) system, how is zone temperature control typically achieved?

Accepted Answer

Using a reheat coil in the zone terminal

Answer

CAV systems maintain constant airflow and use zone reheat coils to raise supply air temperature as needed for individual zone temperature control.

Question 3

What is 'static pressure' in duct system design?

Accepted Answer

The pressure acting perpendicular to airflow on duct walls

Answer

Static pressure is the pressure exerted outward on duct walls perpendicular to the direction of airflow, driving air through the distribution system.

Question 4

A two-pipe changeover hydronic system limitation is that it:

Accepted Answer

Cannot provide heating and cooling to different zones at the same time

Answer

Two-pipe changeover systems use the same piping for either hot or chilled water, so all zones must be in heating or cooling mode simultaneously.

Question 5

What is the purpose of a bypass duct or 'dump zone' in a zoned forced-air system?

Accepted Answer

Relieve excess system pressure when zone dampers close

Answer

A bypass duct diverts excess supply air back to the return plenum when multiple zone dampers close, preventing excessive static pressure on the blower.

HVAC Practice Test

HVAC Practice Test

HVAC System Design 3