HVAC Chapter 7
Energy management systems can save an average of about ___% of overall building energy consumption and cut 20-30% off electricity demand costs.
10
Low-temperature water systems have a maximum operating pressure of _______ psi and a maximum temperature of 250 degree's F.
160
Typically buildings with more than ______________ square feet floor area or those with complex HVAC systems are best controlled by BEMS.
25,000
As a rule, all supply and return air ducts and plenums should be insulated with a minimum of R-______ insulation when located in unconditioned spaces.
5
Ductwork located outside of the building envelope should be insulated with a minimum of R-_____ insulation.
8
What ASHRAE standard is for buildings, except low-rise residential buildings?
90.1-1989
High-efficiency particulate arresting (HEPA) filters remove ______% of particles as small as 0.3 microns.
99.7
is a preassembled or site-built equipment device containing coils and fans that is used to condition and circulate air as part of an HVAC system.
AHU
distribution system is an air-handling configuration that provides a steady airflow into a room or group of rooms while varying the temperature of the air to meet heating and cooling demands.
CAV
is a factory-made assembly that uses special design and construction features that provide unusually quiet operation. Terminals of this type are used in broadcast studios, libraries, and other applications where a minimum-noise, premium-quality terminal is required.
CV
fan is a fan in which the air is turned from parallel to the axis of rotation on entry to a direction tangential to the arc described by the tips of the rotating blades or vanes. It is also known as a squirrel cage fan.
Centrifugal
A cooling coil has what liquid medium within it?
Chilled water coming from the chiller.
consists of a network of tubes in which a hot or cold fluid such as water is circulated.
Coil
Cooling coils that have refrigerant are also termed
DX coils
is a hollow pipe or conduit that conveys and transfers air in a heating, ventilating, and cooling system.
Duct
A duct system, frequently called ______________, is a network of ducts that confines and channels air and serves as the distribution system in a heating, ventilating, and cooling air system.
Ductwork
is designed into a building's air-handling system to cool with outside air instead of using air conditioning equipment to cool indoor air.
Economizer
Air cleaners are classified by the size and thickness and system they work with
F
Axial fans have more mass farther from the axle, which requires more starting torque, but they are generally quieter than centrifugal.
F
Chilled beam systems are stand-alone systems that do not receive ventilation air
F
Dual duct systems are more efficient because of leakage of warm air from the hot duct, which provides additional load to the space.
F
Duct tape is acceptable for a duct sealing process.
F
During the cooling cycle, a VAV fan remains on to ensure cool air gets to the conditioned space.
F
Outside air supply ducts located outside of the building envelope are required to be insulated with an minimum R-4 insulation.
F
The longitudinal joints are the only joints that are required to be fastened and sealed.
F
Thermostats can be mounted on any wall as long as it is inside the envelope of the structure?
F
Thermostats used for hot water systems are usually only the day-night type thermostat.
F
provides heating/and or cooling by circulating steam, hot water, or chilled water piped in from a central plant. It consists of a filter, fan(s), and separate hot water and chilled water coils or a single water coil that may be used for both functions. It can be hidden behind the wall or ceiling or located directly in the room.
Fan Coil Unit
type ductwork is typically used to connect diffusers, mixing boxes and other terminals.
Flexible
The purpose of using a heating coil is to:
Heat the airstream that is going over the coil to carry heat to the conditioned space.
The ICC (International Code Council, wrote what standard for mechanical systems?
IMC
is an air handling unit that conditions 100% outside air
MAU
generally consists of a sheet metal (or similar material) flap, shaped to fit the inside of a round or rectangular duct. By rotating a handle located outside the duct, a technician can adjust air flow to match the needs of a particular zone or room.
Manual damper
is a network of ducts and fans that introduce outdoor air into a building.
Mechanical Ventilation
What type of a control uses compressed air to control equipment?
Pneumatic control
is a factory-made assembly that has hot water or steam reheat coils or electric-resistance heaters within the box. This type of device can increase the temperature of the airstream by reheating it before it enters a space that does not need the desired cooling.
RH
A day-night thermostat permits the setting of one temperature for the daytime and another lower for nighttime.
T
A method to provide zone control on a single HVAC system is by dividing the building into zones that are served by a single HVAC distribution system. Each zone has its own sensors and controls.
T
All-water HVAC systems heat and cool by circulating hot water from a boiler or chilled water from a chiller through a finned coil in a fan-coil unit or unit ventilator in the space.
T
Balance dampers are not intended to be used in applications as a positive shutoff or automatic control damper.
T
Coil selection is based on the amount of sensible or latent heat that must be transferred to the airstream; the design conditions of air entering and leaving the coil; coil construction, water or refrigerant velocity; and face velocity of the airstream.
T
Fans in unit ventilator cabinets draw recirculated air from the room and ventilation air from the outdoors through louvers on an exterior wall.
T
Insulation is generally not required for duct when the design temperature difference between the interior and exterior of the duct or plenum does not exceed 15 degrees F.
T
The effectiveness of air cleaners in removing pollutants from the air depends on both the efficiency of the device itself, and the amount of air handled by the device.
T
There are two primary configurations of air distribution systems (excluding packaged units): constant air volume (CAV or CV) systems and variable air volume (VAV) systems.
T
WHLP systems saves energy by transferring excess heat from one zone to a zone requiring heat.
T
You should keep a thermostat from the cold air drafts, away from any possible warm air drafts, and away from any direct sunlight.
T
distribution system is an air-handling configuration that holds supply air to a constant temperature and controls temperature within a space by variant the quantity of supply air.
VAV
The piece of equipment that adjusts the rotational speed of the electric motor so that it closely corresponds to the varying heating and cooling load requirements is called the
VFD
are used to control the flow of water and liquid through a hydronic distribution system.
Valves
is a mechanism that causes a device such as a damper or valve to be adjusted or turned on or off.
actuator
fans are propeller-type fans that use a propeller to draw air into the fan and discharge it in the same axial direction: airflow, at all times, from entry to exit is predominantly parallel to the axis of rotation.
axial
are used in HVAC systems to allow airflow in one direction and prevent airflow in the opposite direction.
backdraft damper
A very good method of providing occupancy-based ventilation control is to use a
carbon dioxide sensor
What must be provided to remove condensation that is formed during the cooling process on cooling equipment?
condensate drain
is a heating distribution device that is constructed of one or more finned tubes that carry steam or hot water and that transfer heat by circulation of air (natural convection).
convector
is an airflow control device used in ductwork to vary the volume of air passing through an air outlet, air inlet, or duct.
damper
are supply outlets of an air distribution (duct) system with built-in louvers or deflection devices that throw and disperse air to promote good air circulation and temperature equalization in the conditioned space.
diffuser
The electric motor that runs most HVAC fans is called a
drive
is a thick adhesive that is applied to ductwork joints to fill gaps and it dries to a soft solid state
duct mastic
is a mechanical device that uses rotating airfoil blades or vanes to continuously move air.
fan
is located in the HVAC ductwork and automatically closes to obstruct smoke and fire from the building blaze.
fire damper
have sets of vertical and horizontal vanes that deflect the air stream vertically and horizontally. On the return type, the vanes are typically fixed.
grille
is a shutter-like device with fixed slats or vanes that are angled to admit or release air, to provide privacy, and to keep out rain and noise.
louvers
What type thermostat can be used in your home to match the temperature set points with the timing of your space needs?
programmable
is a mechanical device used to compress a liquid or drive flow in a fluid. They are typically driven by an electric motor.
pump
is a heating distribution device that transfers heat from steam or hot water by radiation to objects within visible range and by conduction to the surrounding air that, in turn, is circulated by natural convection.
radiator
is a grilled equipped with a built in damper.
register
The least costly system within the CAV and VAV system is the
single duct
What type filters reduce the level of sound moving through the ductwork
sound-atenuating
are used in duct bends and elbows to effectively direct the airflow through the turn or bend.
turning vanes
is a type of unit that has the capacity to introduce ventilation(outdoor) air into a room in addition to being able to provide space cooling and/or heating. It is a type of fan-coil unit.
unit ventilator
is an area of a building, such as a single room or set of rooms, that has thermal and/or humidity requirements requiring separate control.
zone
