Air Handling Units
Buffalo Fan Co.
offers two major gas fired Air-Handling Unites (AHU) types: direct
and indirect gas-fired.
DIRECT GAS-FIRED AHU
Direct gas-fired AHUs have a gas burner installed
the outside makeup-air stream. The products of combustion (carbon
dioxide [CO2], carbon monoxide [CO], nitrogen
dioxide [NO2]) are discharged directly into the
makeup air stream and supplied to the building area.
INDIRECT GAS-FIRED AHU
An indirect gas-fired AHU has a sealed combustion chamber
where all products of combustion are discharged through a flue to the
outside environment and no products of combustion are discharged within
the make-up air supplied to the building. Such equipment also
frequently is utilized for recirculating-air applications.
Though simple in principle of operation, direct gas-fired
AHUs have sophisticated burner-control systems. Unit sizes range from
1,000 cfm with a heating capacity of 80,000 Btuh to 100,000 cfm with a
heating capacity of 15 million Btuh. Direct-gas-fired-AHU components
usually include housings, supply fans, outside air intake hoods, intake
dampers, filters and burners.
AIR HANDLING UNIT HOUSINGS
AHU housings are made of galvanized or aluminized steel.
Access panels are provided to access dampers, filters, burners, and
fans / motors. AHUs located outside are provided with a sloped roof and
standing seam joints.
AHU SUPPLY FANS
Fans typically are double-width double-inlet (DWDI) with
forward-curved or backward-inclined blades. Fans can come with open
drip-proof (ODP) or totally
enclosed fan cooled (TEFC) motors. The most typical external static
in the 2- to 3-in.-wg range. Because most outside istalled air handling
can operate below 0°F, fan motors and bearings are rated to
lower temperatures. For applications that require supply-air
temperatures higher than 110°F, the motors and fan bearings are
rated for maximum design
operating temperatures when placed in draw-through configurations.
AIR INTAKE DAMPERS AND HOODS
Outside air intake hoods or weather hoods are designed
installation specific location and usually provided with bird screens.
intake isolation dampers are furnished to prevent cold air from
through a unit into a warm building and warm air from escaping through
unit during winter months, when it is not in operation. Low-leakage
parallel blade isolation dampers are most standard. The fan discharge
is located at the opposite to isolation-damper position.
A filter cabinet normally has 30 / 30 filters in a V-bank
configuration to increase filter area and reduce static-pressure drop
across the filters. Higher-efficiency filters are used on application.
A burner consists of a cast-iron or aluminum pipe
drilled gas orifices. The fuel-air mixing is controlled by perforated
baffles attached to the pipe assembly. The burner can be placed in the
airstream or in the outside / return mixed-air stream. But to prevent
hazardous combustion byproducts of indoor-air contaminants, the burner
placed in the outside airstream only. The required airflow across the
must be within a specific velocity range (typically 2,500 to 3,500 fpm)
proper combustion. For variable airflow units, a modulating bypass
or profile plate maintains the airflow velocity within the specified
range. Otherwise, the burner can experience inefficient operation,
odors in the occupied spaces served, and create an un-safe increase in
products of combustion.
Buffalo Fan Co.
Air Handling Units are well-known for:
LONG SERVICE LIFE: We use premium quality industrial-grade
materials and additional protective coatings for external surfaces and
internal components of our Air Handling Units - to withstand the
specific gases flow and the installation
conditions of each application, industrial and commercial /
CAPACITIES: Up to 100,000 CFM for
standard construction and larger, custom made on special request.
FLEXIBILITY: Every unit is designed
for the specific installation and connections conditions. The unit
floor area and its cross section dimensions are adjusted for precise
room available at
EASY INSTALLATION: Packaged compact
or sectional design provided with lifting arrangement and protections
for easy transportation and handling / installation at site.
LOW MAINTENANCE: Service
friendly design which provide large room inside cabinet, access doors,
light and rigid floor ensuring accessibility to all components.
HIGH EFFICIENCY: Fans, coils, motors,
humidifiers, filters, external insulation material, silencers,
enclosure tightness, and other components are carefully selected and
engineered for lowest energy consumption.
OPERATIONALLY SAFE: Safety devices
and guards are provided in accordance to the international regulations
and the customer specific requirements.
PRECISE PERFORMANCE: To match the
customer capacities requirement utilizing
the computerized selection for each component.
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