Indirect / Direct Evaporative Cooling Units

INDIRECT / DIRECT EVAPORATIVE COOLING UNITS

1. GENERAL

A. The indirect/direct evaporative cooling unit shall be a factory assembled package, complete with indirect evaporative air to air heat exchanger, direct evaporative media, wet side fan, water pump, weather proof intake air hood (louvers) water distribution manifold and nozzles, moisture eliminators, float valve, overflow, and drain.

B. The unit manufacturer shall be Energy Labs, Inc.

2. PERFORMANCE

The performance of the system shall be as scheduled on the drawings.

3. COMPONENTS

A. INDIRECT CASING

1. The unit casing shall consist of 18 gauge 304 stainless steel panels, 16 gauge 304 stainless steel water pump and 12 gauge 304 stainless steel support legs, the unit shall be of welded construction.

2. The casing shall be reinforced with 304 stainless steel structural members to provide structural integrity. All joints and seams shall be silicone caulked to prevent air leakage and to insure water tightness.

3. Hinged access doors shall be constructed with turned in edges for maximum rigidity and to receive insulation. The access doors shall be neoprene gasket to insure a tight seal.

B. INSULATION

1. Unit casing shall be insulated with 1 1/2 lb. Density, neoprene coated, NFPA 90A approved, acoustical fiberglass insulation with a minimum thickness of one inch.

2. The insulation shall be secured to all inside surfaces with mechanical fasteners at a maximum of 12” on center.

C. INDIRECT EVAPORATIVE HEAT EXCHANGER 1. The air to air exchanger shall be constructed with non-corrosive, non- metallic, vertical square tubes to eliminate stress and protect from calcium deposits.

2. The headers shall be 3/16” inch thick non-corrosive, non-metallic sheets solvent welded to the tubes.

3. Water shall be evaporated on the inside of the tubes for complete sensible cooling.

4. The minimum heat exchanger capacity and efficiency shall be as scheduled.

D:* DIRECT EVAPORATIVE COOLING MEDIA:

1. The indirect evaporative media shall be “CELdek” or “GLASdek” as manufactured by Munters Corporation.

CELdek EVAPORATIVE MEDIA:

a. This media shall be 12” thick and made from cellulose paper impregnated with insoluble anti-rot salts and rigidifying saturants to provide the maximum evaporation with a minimum of deposition of solids.

GLASdek EVAPORATIVE MEDIA:

b. The direct evaporative media shall consist of GLASdek, as manufactured by Mumters Corporation .This media shall be made from large glass fibers bounted together by inorganic, non-crystal line fibers to provide the maximum evaporation with a minimum of deposition of solids. It shall be UL approved with a UL900, class 2 rating. Required for ETL listing.

2. The media shall not experience water carryover at air velocities below 700 feet per minute.

*Note to Specifying Engineer: The direct evaporative media may be either CELdek or GLASdek. Typically CELdek is used and is sufficient for most applications. When ETL listing is required, specify GLASdek. The performance of both is essentially the same.

E. WATER DISTRIBUTION SYSTEM

1. The water distribution manifold shall be constructed of schedule 80 PVC piping. 2. The spay nozzles shall be brass, designed to provide uniform distribution over the entire heat exchanger.

3. The water make-up valve shall have a brass body with an adjustable float valve.

4. The water distribution system to include an overflow, a drain connection, and an adjustable bleed valve to prevent build up of solids.

5. Water circulating pump shall be end suction with cast iron volute and seal plate. The impeller shall be fiberglass reinforced polycarbonate with brass insert. The motor shall be close coupled, permanently grease lubricated, shielded ball bearing, threaded stainless steel shaft. The performance, size, and electrical characteristic of the pump shall be as scheduled.

6. The pump shall be protected against low water level in the sump with low water cut off safety switch.

7. Water distribution system and nozzles shall be protected with inline cleanable strainer. Strainer shall have type 304 stainless-steel screen.

F. WETSIDE FAN

1. Wet side fan blade(s) shall be constructed of glass reinforced polypropylene. Fan hubs shall be cast aluminum and allow for manual adjustment of blade pitch.

2. Orifice ring shall be constructed from 14 gauge 304 stainless-steel and the motor mount shall be constructed from 12 gauge 304 stainless steel.