Guide
Specification
The contractor is to furnish and install factory assembled
indirect evaporative units, direct evaporative units and connecting ducts sections.
Option : The units and connecting duct section will be
factory mounted on a common 6 inch base.
Option : The units and connecting duct section will be
field connected .The Indirect/direct system will cool _____ CFM of supply air from ____
"FDB entering air temperature with entering condition of ____ "F-DB and
____"FWB. The total static pressure loss of the I/D system will be ____ inches WG.
The ______ Contractor will be furnish material and provide
the water make-up connection, strainer and shut-off valve(1/2"), overflow connection
(3/4") and drain connection with shut-off valve (3/4"),
Option : Solenoid shut-off and drain valves will be
provided for non freeze protection.
The _______ Contractor will furnish and install the
electrical connections to the indirect and direct unit pumps and indirect secondary air
fan(s)
Option: Thermostatic control will be provided for the
non-freeze solenoid valves.
INDIRECT UNIT : Vari-Cool model no. ____________ factory
assembled components with _______ core assemblies operating at _____ CFM per core
with an efficiency of _____ % and pressure drop of _____ inches WG. Secondary air will be
provided at a nominal rate of 850 CFM per core at a pressure drop of .17 inches WG
and consist of a factory assembled, side mounted, plenum and horizontal discharge
fan(s) section.
Option : The secondary fan and plenum section will be
field provided and assembled.
Option : Two indirect units will be factory mounted in
parallel on a common base with a common connecting secondary air plenum and vertical
discharge fan(s).
Option : Two indirect units will be field mounted in
parallel, and a common connecting secondary air plenum and vertical discharge fan(s).
The unit(s) will contain factory installed louvers on the
inlet of the secondary side.
Option : The unit(s) will be factory furnished with modular
screened inlet cowls to be field installed on the duct flange to the inlet of the primary
(dry) side.
The heat transfer surface area will be corrosion -free high
impact polystyrene tubing with polystyrene headers, constructed in modular tube and header
assemblies. The surface of the heat transfer tubes will be fitted with sleeves of
corrosion-free knitted plastic which is totally inert, 100% synthetic, and will
provide high water retention and total water contact to the exterior of the transfer
tubes. The heat transfer tubes will be solvent welded (including a secondary flooding
process) to 1/4" structural polystyrene headers. Each modular tube-core assembly will
contain 165 tubes comprising 226.8 square feet of heat transfer area. The tube
core assemblies will be connected to the cabinetry with stainless steel retainers and
stainless steel expansion joints will be provided to allow for thermal expansion and
contraction of the header assembly.
The water distribution will be factory pre-piped, requiring
no balancing valves. The water distribution pan will be of non-corrosive synthetic
material with distribution to cover each tube on maximum 6" center points. Two sleeve
type synthetic water filters will be installed ahead of the water distribution pan. These
filters will be high capacity and contains 200 square inches of low porosity media area.
Factory installed and calibrated water bleed-off assemblies will be piped to the overflow
fitting.
DIRECT UNIT: Vari-Coll model no. _________ factory
assembled components matching the indirect unit size in air quantity, face velocity and
connecting duct dimension. The unit will operate at ______ CFM with a face velocity of
_____ FPM., and efficiency of ____ % and pressure drop of ____ inches WG.
Option : The direct evaporative unit will be manufactured
to match the duct connection of the fan or fan coil section and will operate at ____CFM
with a face velocity of _____ FPM, and an efficiency of ____ % and pressure drop of ___ in
WG.
The evaporative media will be made from cellulose paper,
impregnated with insoluble anti-rot salts, rigidifying saturants and wetting agents.
Water distribution will be by means of a horizontal pipe
header with jetting holes at the top of the pipe. The distribution pipe is removable and
contains end caps for easy cleaning. The jetted water is impigned on an inverted
distribution pan allowing a thorough sheeting on the distribution pan allowing a thorough
sheeting on the distribution pad. The two inch horizontal distribution pad is crossfluted
and disperses the water evenly over the evaporative fill material. The water distribution
rate will be approximately 2.7 GPM per square foot of horizontal distribution pad area.
CABINETERY & CORROSION PROTECTION:
The basic cabinetry of the indirect and direct units will
be constructed of 16 Ga. No. 304 stainless steel. Fasteners will be stainless
steel. Primary and secondary air flow duct connections will be flanged Mounting
rails will be provided in order to secure the unit. Accessibility will be provided
to all service areas.
All accessories will be constructed of aluminized
metal. For corrosion protection the aluminized metal surfaces are to be factory coated
with a heavy mil coating of epoxy paint.
CONNECTING DUCT SECTION(S) :
Factory furnished economizer type interconnecting duct
section will be provided will operable outdoor air and return air damper sections.
Operators and linkage are optional . An accessible 2" filter bank will be
provided.
Option : Chilled water (or direct expansion) 3rd stage
cooling coil(s) and condensate pan with drain fitting will be factory provided ahead of
the direct unit.
Note: The above options apply to hot water or steam coil(s)
also.
Option : Factory furnished and close coupled
interconnecting cooling-only duct section (no return air provisions) will be provided.
Connecting duct sections will be fabricated of aluminized
steel and will match the flange duct connections sizes of the indirect and direct
units. The exterior of the duct will be coated with epoxy paint, and the interior lined
with 1" insulation duct liner.
FLOAT VALVES:
Brass body and stem, adjustable water make-up float valves
will be factory furnished and installed.
PUMPS :
Pumps will be factory furnished, for field installation,
submerged in the basin of the indirect and direct units. Connecting hose and piping will
be factory furnished. The pump suction will be factory fitted with an anti cavitation
fitting. Capacity:9 GPM at 11 foot pumping head. The pump will be permanently lubricated
with nylon impeller ., U.L. listed and a nameplate of 300 watts (115V-60C-10)
Option : A field-installed central pumping plant will be
provider. The indirect and direct units will be fitted with oversize (1 1/2")
free-gravity drain suction connections.
U.V PROTECTION
All factory furnished plastics are to contain ultraviolet
inhibitor additives for protection against indirect sunlight.
FILTERS:
2" cleanable, thrown away and extended surface are
available.
Options : High capacity filters banks are available in lieu
of the standard 2" filter sections.
NON FREEZE PROTECTION :
Optional Automatic, thermostatically controlled solenoid
drain, and shut-off valves are recommended. Maintain basin water temperature at minimum
35°F
SCALE & ALGAE CONTROL:
Indirect and direct units contain factory installed water
bleed-off assemblies to provide an approximately bleed rate of 5 % of the recirculated
flow rate. This will provide an adequate prevention of excess scale formation. In areas
where water hardness is usually high, water treatment, similar to that required for
towers and condenses, may be considered. Due to the minimal temperature difference in the
heat exchange of VARI-COOL equipment scale formation is usually soft and will be washed
down in the unit operation and in maintenance procedures. If required, the indirect unit
can be de scaled with commercial descaling agents, during system normal operation. If
recommended procedures are followed there will be no not cause deterioration of rot and
can be controlled by a commercial algaecide. See WATER TREATMENT bulletins for
recommendations of algae and scale control.
 
In order to maintain our policy of continuous product
improvement, we reserve the right to change prices, specifications, rating or dimensions
without notice or obligation. |
