Unit 79
The amount of outside air introduced can be controlled using
A CO2 sensor
Which part of a large office building generally requires cooling all year, even when it is cold outside?
Core
Which of the following statements is most accurate? A. Core systems must adjust to accommodate variables such as wind effects. B. Core systems are subject to a wider range of variables than perimeter systems. C. Perimeter systems only need to accommodate loads such as electrical equipment and lighting. D. Perimeter systems accommodate many of the loads of the core system and loads caused by weather.
D. Perimeter systems accommodate many of the loads of the core system and loads caused by weather.
In perimeter applications using the variable-air-volume system, the primary air handler provides
Variable volume and constant temperature
A single-zone, constant-air-volume system is best suited for conditioning
a building's core area
Outside air is drawn into the building through
an outside air damper
How does an energy-recovery wheel improve system efficiency?
by transferring heat between the ventilation air and the exhaust air
Constant-air-volume systems can deliver different levels of heating and cooling
by using variable-air-volume mixing boxes
A unique feature of multizone and double-duct systems is that they
can heat and cool at the same time using a single air handler
In the event of a fire, fire dampers prevent oxygen from feeding the fire by
closing off the outside air supply completely
In multizone systems with one trunk duct to each zone, what is used to adjust the temperature of the air?
hot and cold decks
In a single-zone, constant-volume system, which floors only have provisions for cooling?
intermediate floors
The perimeter system is often used alongside a core system in
larger buildings
Under normal operations, some outside air will always be included to
prevent excessive levels of CO2 from building up
A multizone system allows a wide range of temperatures in different zones supplied by a single unit by
providing a blend of always-available heated and cooled air to any zone
In a single-zone, constant-air-volume system, the amount of air moving through the air handler
stays the same all the time
The perimeter of a large multistory high-rise building consists of
the areas around the outside of the building
How does an energy-recovery wheel transfer latent heat between the ventilation and exhaust air?
the desiccant in the wheel absorbs the moisture in the air
When a VAV box on a constant-air-volume system throttles air into the conditioned area
the excess air dumps into the area above the ceiling
The core of a large multistory high-rise building consists of
the interior areas
What is the purpose of the hot and cold decks on a multizone system?
they provide simultaneous hot and cold air
Why would a preheat coil be used on the energy-recovery wheel?
to prevent frost from forming on the wheel