Job: 03-30364 Title: Rp-Architecture Reference & Speciﬁcation
#175 DTP: 216 Page: 72
72 THE ARCHITECTURE REFERENCE + SPECIFICATION BOOK
Chapter 6: Mechanical Systems
A building’s mechanical systems involve control of heat, ventilation, air-conditioning,
refrigeration, plumbing, re protection, and noise reduction, all of which must be
integrated with the architectural, structural, and electrical design.
ENERGY DISTRIBUTION SYSTEMS
All-air Systems: Conditioned air is circulated to and from spaces by central fans that direct
it through runs of ductwork.
Air and Water Systems: Conditioned air is ducted to each space, and chilled and heated
water are piped to each space to modify the temperature of the air at each outlet.
All-water Systems: No ductwork is used, and air is circulated within each space, not from a
central source. Chilled and heated water are furnished to each space. Because water piping
is much smaller than ductwork for air, all-water systems are very compact.
Air duct: Pipe that carries warm and cold
air to rooms and back to a furnace or air-
ASHRAE: American Society of Heating,
Refrigerating, and Air-Conditioning Engineers.
Cavity wall: Hollow wall formed with two lay-
ers of masonry, providing an insulating
air space between.
Chase wall: Cavity wall containing electrical
runs or plumbing pipes in its cavity.
Closed loop: Evaporator side of chiller
system, closed to the atmosphere.
Dry bulb: Ambient outside temperature.
Furnace: Device that generates heated air,
and is powered by natural gas, fuel oil, or
electricity. Most often used in small commer-
cial or residential applications.
Heat pump: A device that warms or cools by
transfering thermal energy from a heat source
to a heat sink.
HVAC: Heating, ventilating, and air-condition-
IAQ: Indoor Air Quality
Louver: Opening with horizontal slats that
permit passage of air, but not rain, sunlight, or
view, into a structure.
Plenum: Chamber that serves as a distribu-
tion area for heating or cooling systems,
usually found between a false ceiling and
the actual ceiling.
Open loop: Condenser/tower side of chiller
system; open to the atmosphere.
Radiant heat: Heating system that uses
coils of electricity, hot water, or steam
pipes embedded in oors, ceilings, or
walls to heat rooms.
Shaft: Enclosed vertical space (usually with
re-resistive walls) containing all vertical runs
of pipes, ducts, and elevators.
Variable air volume (VAV): Air-handling system
that conditions air to a constant temperature
and varies airow to ensure thermal comfort.
Wet bulb: Combination of outside air tem-
perature and relative humidity; higher relative
humidity makes it more difcult for a cooling
tower to evaporate water into the atmosphere.
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