Evaporative Cooler
Minimum Efficiency, Percent
where:
T1 is the entering dry-bulb temperature in degrees F.
T2 is the leaving dry-bulb temperature in degrees F.
Tw is the entering wet-bulb temperature in degrees F.
PART 2
PRODUCTS
2.1
SINGLE-STAGE EVAPORATIVE COOLERS
[Drip-type with stationary wetted pad] [Rotary-type] with revolving drum or
disk. [Washer (eliminator) type.]
2.1.1
Evaporative Media (Limited specie of wood)
Refined cellulose fibers. [Impregnate fibers with copper 8-quino-linolate
or other equivalent fungicides.] [Rotary filters with maximum 3 m/s 600 FPM
and 2 1/2 percent by-pass water flow through the rotary assemblies and
minimum 127 mm 5 inch depth of rotary sections.] [Washer media consisting
of self-cleaning centrifugal brass spray nozzles, brass flooding nozzles,
[copper] [or] [galvanized steel] water piping, centrifugal water pump,
strainers, and a minimum 24 gage [galvanized steel] [or] [aluminum]
eliminator with minimum four surfaces and three bends in the airflow
direction.]
2.1.2
Water Reservoirs
Fabricate tank from minimum 20 gage zinc-coated steel, bronze, or stainless
steel, with a capacity of 19 liters 5 gallons water for each 472 L/s of air
1,000 cubic feet of air per minute passing through the cooler section.
Coat the entire water reservoir surfaces with minimum 0.254 mm 10 mils
bituminous coating after the fabrication.
2.1.3
Automatic Flush (Electric Dump) Valves and Timers
Provide cast bronze valves with neoprene-diaphram solenoid and timer.
2.2
TWO-STAGE (COMPOUND) EVAPORATIVE COOLERS
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NOTE: An indirect-section evaporative cooler is the
first stage of cooling, which lowers both dry-bulb
and wet-bulb temperatures of the incoming supply
air. This supply air is then passed through a
direct-section evaporative cooler which provides the
second stage of cooling. The first stage of cooling
is at constant humidity ratio, while the second
stage is at constant wet-bulb temperature.
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Self-contained, packaged, pre-wired, and factory-fabricated evaporative
coolers with indirect and direct sections for two-stage cooling.
2.2.1
Indirect Section
Indirect sensible cooler with a complete secondary evaporative cooling
system. Include components of heat exchanger, evaporative media,
recirculating pump with suction strainer, sump drain, overflow, automatic
fill and level control, secondary air exhaust fan, and distribution head
SECTION 15721N
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