Which type of economizer is capable of choosing between outside air or return air, based on the

enthalpy of the two airstreams? Integrated economizers

A multi-zone constant volume system is well-suited for buildings in which _____.

the control zone arrangement is permanent

Comfort is normally associated with the air properties of _____.

temperature and relative humidity

In order to modulate the flow of supply air, VAV systems may use inlet guide vanes on the

fan inlet or _____. variable speed drives

In VAV systems with a return air fan, the fan provides _____.

the amount of air, supply fan is moving, minus outside air

single-zone constant-volume system w/ economizer installed; occupied mode, & call for cooling

which occurs-The economizer=1st cooling, f conditions permit

What characteristic makes a grille into a register?

An adjustable damper installed behind the face.

In a VAV system, the demand for heat is satisfied by _____.

a heater attached to the VAV terminal

When a parallel fan-powered VAV box is in the heating mode, the primary air damper is _____.

at its minimum position setpoint

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NCCER HVAC II Module 11 Commercial Airside Systems

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A Quiz to help understand Commercial Airside

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Questions 15

Answers

1
The simplest form of economizer control is the _____.
dry-bulb method
powered exhaust method
enthalpy method
integrated method
2
Which type of economizer is capable of choosing between outside air or return air, based on the
enthalpy of the two airstreams? Dry-bulb economizers
enthalpy of the two airstreams? All economizers
enthalpy of the two airstreams? Integrated economizers
enthalpy of the two airstreams? Enthalpy economizers
3
The maximum safe concentration of carbon dioxide (CO2) in an occupied space is _____.
1,000 ppm
1,200 ppm
1,500 ppm
900 ppm
4
A multi-zone constant volume system is well-suited for buildings in which _____.
the control zones are likely to be rearranged regularly
the control zone arrangement is permanent
the zones are very small
cooling & heating are required at same time in the same zone
5
Comfort is normally associated with the air properties of _____.
dew point and relative humidity
temperature and dew point
temperature and enthalpy
temperature and relative humidity
6
The primary source of heat for a year-round packaged air conditioner is _____.
hot water
electricity
steam
natural gas
7
In order to modulate the flow of supply air, VAV systems may use inlet guide vanes on the
fan inlet or _____. powered exhaust
fan inlet or _____. variable speed drives
fan inlet or _____. an economizer
fan inlet or _____. hot gas bypass
8
In VAV systems with a return air fan, the fan provides _____.
50 percent of the air that the supply air fan provides
more airflow than the supply air fan provides
the amount of air, supply fan is moving, minus outside air
the same amount of air that the supply air fan is moving
9
single-zone constant-volume system w/ economizer installed; occupied mode, & call for cooling
which occurs The supply air fan stops
which o occurs The outdoor dampers move to fully closed.
which occurs The relief fan cycles on.
which occurs-The economizer=1st cooling, f conditions permit
10
What is one characteristic that sets VVT systems apart from the other approaches?
Heating and cooling can be provided simultaneously
It's ideal 4 zones with very different heating cooling needs
The need for a bypass damper.
Heating cannot be provided by the central unit.
11
What characteristic makes a grille into a register?
Widely spaced louvers on the face
An adjustable damper installed behind the face.
The absence of an adjustable damper behind the face
Being designed to fit into a 24 × 24 suspended ceiling grid
12
In a VAV system, the demand for heat is satisfied by _____.
independent baseboard heat
an independent heat pump
electric heaters in the air handler
a heater attached to the VAV terminal
13
When a parallel fan-powered VAV box is in the heating mode, the primary air damper is _____.
fully open
fully closed
used to control heating airflow
at its minimum position setpoint
14
The packaged unit accessory used to prevent compressor oil from absorbing refrigerant is a(n)
_____. oil defroster
_____. outdoor thermostat
_____. economizer
_____. crankcase heater
15
Which type of system is designed to maintain a constant supply air temperature of 50°F and 60°F
year-round? Economizer
year-round? VVT
year-round? Multi-zone
year-round? VAV

NCCER HVAC II Module 11 Commercial Airside Systems Flashcards | StudBud