Factory Assembled Cooling Towers

LSTE Cooling Tower

LSTE Cooling Tower

The LSTE is a forced draft, centrifugal fan design cooling tower with a capacity range of 33 to 1,300 nominal tons (147 to 5715 kW). Standard construction consists of G-235 (Z725-Europe) galvanized steel with type 304 stainless steel available for the basin or the entire tower.

The LSTE Cooling Tower product line is highly efficient design constructed for long life and minimum maintenance. It is the ideal choice for forced draft replacement applications, low sound and indoor installations. The LSTE engineered design features are described below. 

Principle of Operation

Warm water from the heat source is pumped to the water distribution system at the top of the tower. The water is distributed over the wet deck fill by means of large orifice nozzles. Simultaneously, air is forced through the air inlet louvers at the base of the tower and travels upward through the wet deck fill opposite the water flow. A small portion of the water is evaporated which removes the heat from the remaining water. The warm moist air is forced to the top of the cooling tower by the fan and discharged to the atmosphere. The cooled water drains to the basin at the bottom of the tower and is returned to the heat source.

The vertical air discharge of the LSTE design and the distance between the discharge air and fresh air intakes, reduces the chance of air recirculation, since the warm humid air is directed up and away from the unit. For detailed layout information please consult EVAPCO's Equipment Layout Guidelines.

IBC Compliant

What is IBC?
   
The International Building Code requires that evaporative cooling equipment must meet the same seismic or wind load forces as the building to which they are attached.


How does it apply?
   
Based on project zip code and site design factors, calculations are made to determine the equivalent seismic "g force" and wind load on the unit.


What does EVAPCO offer?
   
Standard and upgraded designs for 1.0 and 1.5 importance factor applications.

 

Efficient Drift Eliminators

The final element in the upper part of the cooling tower are moisture eliminators which strip the entrained water droplets from the leaving air stream. EVAPCO's patented eliminator insures that drift loss will be minimized. The eliminators are approximately 5" deep (127mm) , spaced on 1" (25,4mm) centers. They incorporate a hooked leaving edge designed to direct the discharge air stream away from the fans to help eliminate recirculation of hot, saturated air back into the fan inlets.

The air discharge side of the cooling tower is the most corrosive and most difficult area to clean and refinish. To provide the greatest protection in this area, the drift eliminators are made of inert polyvinyl chloride (PVC). The PVC material will effectively eliminate corrosion of this vital components and is specially treated to resist ultraviolet light.

The eliminators are assembled in easily handled sections to facilitate removal. This will expose the entire upper portion of the unit and water distribution system for periodic inspection. 

EVAPAK® Fill

The EVAPAK® fill design used in the LSTE Cooling Tower is specially designed to induce highly turbulent mixing of the air and water for superior heat transfer. Special drainage tips allow high water loadings without excessive pressure drop. The fill is constructed of inert polyvinyl chloride, (PVC). It will not rot or decay and is formulated to withstand water temperatures of 130ºF (54,4ºC). Because of the unique way in which the crossfluted sheets are bonded together, and the bottom support of the fill section, the structural integrity of the fill is greatly enhanced, making the fill usable as a working platform. The fill selected for the Cooling Tower has excellent fire resistant qualities. Cooling Tower fill has a flame spread rating of 5 per ASTM-E84-81a. A higher temperature fill is available for water temperatures exceeding 130ºF (54,4ºC). Consult your EVAPCO representative for further details.

Low Sound Design

Centrifugal fan units provide an inherently low noise characteristic which makes this design preferred for most installations that require low sound levels. The sound they produce is predominantly in the high frequencies which is easily attenuated by building walls, windows, and natural barriers. Additionally, since the sound from the fans is directional, single sided air entry models can be turned away from critical areas avoiding a sound problem. When even quieter operation is necessary, centrifugal fan models can be equipped with optional sound attenuation packages. Consult the factory for details. 

Pressurized Water Distribution System

The water distribution system is made of schedule 40 PVC pipe and ABS plastic water diffusers for corrosion protection in this key area. The piping is easily removable for cleaning. The water diffusers have a minimum opening of 3/8 by 1 inch (9,5 mm by 25,4 mm) and are practically impossible to clog. They also have an anti-sludge ring extending into the headers to prevent sediment from building up in the diffuser opening In addition, the spray branches have threaded end caps to allow easy debris removal.

The spray pressure for all LSTE Cooling Towers is between 1 and 6 psig (6,9 and 42 kPa) at the
inlet header. The actual spray pressure will be shown on the certified drawings which are prepared for each unit. 

Forged Bearing Journal

The fan shafts used on all LSTE models are standard with forged bearing journals. Other brands may use a two-piece fan shaft with welded end journals that is susceptible to rusting and eventual failure. The solid forged design of the LSTE fan shaft provides durable long-lasting operation, free from premature mechanical failure 

Fast, On-Time Shipments

The LSTE is a completely factory assembled cooling tower manufactured by a dedicated professional workforce, expert in building cooling towers. Factory trained mechanics and EVAPCO's strict quality control and inspection procedures guarantee the quality of every unit shipped.

EVAPCO's controlled factory environment ensures fast on-time shipments, allowing the LSTE to be available WHEN THE CUSTOMER WANTS IT!

Designed for easy maintenance, the LSTE cooling tower leads the industry in service friendly features. The two most critical areas for cooling tower maintenance are the basin and the drive system. The cold water basin is easily accessed from outside the tower via large circular access doors. All drive system components are located in the dry, entering air stream for long life and can be serviced from outside the tower.

The pan/fan section of a centrifugal fan unit is designed for accessibility and maintenance. Fan and drive components are positioned to allow easy adjustment and cleaning. All grease fittings are in convenient locations for periodic lubrication. Large circular access doors are provided on each section to allow entry into the pan. All float valve and strainer assemblies are location near the door for easy adjustment and cleaning. The pan sump is designed to catch the dirt accumulated and can be flushed out with a hose

Fan Motor Mount

EVAPCO mounts the fan motor in a convenient open area to make it easy to adjust belt tension, electrically connect the motor, or change the motor if necessary. The fan motor and drive are under a protective cover for safety purposes and to protect them from the elements.
 

Easy Access

The pan/fan section of a centrifugal fan unit is designed for accessibility and maintenance. Fan and drive components are positioned to allow easy adjustment and cleaning. All grease fittings are in convenient locations for periodic lubrication. Large circular access doors are provided on each section to allow entry into the pan. All float valve and strainer assemblies are location near the door for easy adjustment and cleaning. The pan sump is designed to catch the dirt accumulated and can be flushed out with a hose. 

Stainless Steel Strainers

One other component of evaporative cooling equipment which is subject to excessive wear and corrosion is the suction strainer. EVAPCO provides a lasting Type 304 stainless steel strainer on all units (except remote sump applications) as standard. Strainers are positioned around a large anti-vortex hood in easily handled sections.

EVAPCOAT Construction

G-235 Hot-Dip Galvanized Steel Construction
The standard material of construction for evaporative cooling equipment for many years has been hot-dip galvanized steel. The purpose of galvanizing is to protect the base metal from corrosion, and the thickness of the galvanized layer directly affects the equipment life.

EVAPCO has been instrumental in the development of corrosion protection technology and was the first manufacturer to use G-235 (Z600-Europe) galvanized steel construction. The G-235 (Z600-Eurpe) designation equates to a minimum of 2.35 ounces of zinc per square foot (600 grams per square meter) of surface area.

The EVAPCOAT Corrosion Protection System is the heaviest galvanized coating available for extended corrosion protection eliminating the need for costly, unreliable epoxy paint finishes. 

The LSTE Cooling Tower features the highly successful EVAPCO V-belt drive system engineered for heavy-duty operation. All drive system components including the fans, motors, sheaves, and belts are located in the dry entering air stream and are suitable for the most severe duty cooling tower applications. Fan Motors Belt Drive Centrifugal Fans and Drives Forged Bearing Journal Fan Motors.

All LSTE Cooling Tower models utilize heavy duty, totally enclosed Premium Efficient, Inverter-Duty fan motors designed specifically for cooling tower applications. In addition to the standard motors offered on each cooling tower, EVAPCO offers many optional motors to meet your specific needs, including: Premium Efficiency and Multi-Speed Motors.

Fan Motors

All LSTE Cooling Towers come standard with premium efficient, inverter capable fan motors that can be used with variable frequency drive (VFD) systems for precise capacity control. VFD systems can control the speed of a fan motor by modulating the voltage and frequency of the motor input electrical signal. When connected to a building automation system a VFD can receive signals and vary the fan speed to meet demand loads. This popular method of capacity control can yield significant energy savings.

Evapco offers two-speed fan motors as an option for alternative capacity control. In periods of lightened loads or reduced wet bulb temperatures the fans can operate at low speed providing about 60% of full speed capacity yet consuming only about 15% of full speed power. In addition to the energy savings the sound levels of the unit can be greatly reduced by operating at low speed. These motors do not require the use of VFD systems however they can only operate at two speeds: full or low.

Pony motors are available as another capacity control method. Pony motors are smaller fan motors for use in times of reduced loading. The pony motor is typically 1/4 of the HP of the primary motor and can significantly reduce energy requirements. 

Belt Drive

The belt drive system consists of multigrooved V-Belts with high lateral rigidity. The belts are designed for cooling tower service, and are constructed of neoprene with polyester cords. The belt drive is sized for 150 percent of the motor nameplate horsepower ensuring long and trouble free operation.

Centrifugal Fans and Drives

The LSTE features forwardly curved centrifugal fan wheels constructed of hot-dip galvanized steel for strength and efficiency. All fans are statically and dynamically balanced and mounted in a hot-dip galvanized steel housing designed and manufactured by EVAPCO. The drive sheaves are located in the dry entering air stream for longer life and are accessible from the side of the fan and drive enclosure.

Forged Bearing Journal

The fan shafts used on all LSTE models are standard with forged bearing journals. Other brands may use fan shafts with welded end journals that are susceptible to rusting and eventual failure. The solid forged design of the LSTE fan shaft provides durable long-lasting operation, free from premature mechanical failure.

The standard design of the EVAPCO LSTE provides the customer with the easiest cooling tower to maintain in the industry. There are additional options which can make maintenance easier and extend the life of the cooling tower. These options are listed below.

For additional corrosion protection, several stainless steel options are available in either type 304 or for extreme applications, type 316 stainless steel. The LSTE’s modular design allows specific areas to be enhanced from the cold water basin, to water touch panels, up to the entire unit. Combined with EVAPCO’s non-corrosive PVC fill, eliminators, and water distribution system, this is the most effective extended corrosion protection available. Unlike costly, unreliable epoxy paint finishes, stainless steel will not peel or bubble exposing the base metal and clogging the suction strainers.

Stainless Steel Basin

For additional corrosion protection, several stainless steel options are available in either type 304 or for extreme applications, type 316 stainless steel. The LSTE’s modular design allows specific areas to be enhanced from the cold water basin, to water touch panels, up to the entire unit. Combined with EVAPCO’s non-corrosive PVC fill, eliminators, and water distribution system, this is the most effective extended corrosion protection available. Unlike costly, unreliable epoxy paint finishes, stainless steel will not peel or bubble exposing the base metal and clogging the suction strainers. 

Sound Attenuation

Centrifugal fan units provide an inherently low noise characteristic which makes this design preferred for most installations that require low sound levels. If the standard LSTE sound pressure level is not quiet enough for certain applications, the sound levels can be further reduced by adding fan intake and discharge sound attenuators. EVAPCO also recommends the use of Variable Frequency Drives (VFD) or two speed motors for reduced fan speed when operating at less than design load for additional noise reduction.

Fan Inlet Attenuation
Reduces sound radiated through the air intake. It consists of baffled panels to change the path of the air entry and to capture the radiated noise, thus reducing the overall sound levels generated. The attenuator is self-supporting and does not require structural steel support.

Discharge Attenuation
The discharge attenuation hood features a straight sided design with insulated baffles to reduce the overall sound levels of the discharge air. The discharge attenuator incorporates a large access panel to allow entry to the drift eliminators and water distribution system. If a higher discharge velocity is required, a tapered discharge hood that provides minimal sound attenuation is available. 

Screened Bottom Panels

Protective inlet screens are provided on the front of the fan section on the LSTE. Screens are not provided on the bottom of the fan section since most units are mounted on the roof or at ground level. If units are installed in an elevated position, bottom screens are recommended for safety protection.
 

Electric Heaters

Electric immersion heaters are available as an option and are located in the basin of the tower. They are sized to maintain a +40° F (4,4º C) pan water temperature at 0°F (-18º C) ambient with the fans off *. They are furnished with a combination thermostat/low water protection device to cycle the heater on when required and to prevent the heater elements from energizing unless they are completely submerged. All components are enclosed in rugged, weather proof enclosures for outdoor use. Heater control packages that include contactor, transformer or disconnects are available.

(*) - Electric heater selection based on 0°F (-18º C) ambient temperature. For alternate low ambient heater selections consult the factory.

Electric Water Level Control

EVAPCO cooling towers are available with an optional electric water level control system in place of the standard mechanical makeup valve and float assembly. This package provides very accurate control for the basin water level and does not require field adjustment, even under varying operating conditions.

The control was designed by EVAPCO and is manufactured exclusively for EVAPCO. It consists of multiple heavy duty stainless steel electrodes. These electrodes are mounted external to the unit in a vertical stand pipe. For winter operation, the stand pipe must be wrapped with electric heating cable and insulated to protect it from freezing.

The weather protected slow closing solenoid valve(s) for the makeup water connection is factory supplied and is ready for piping to a water supply with a pressure between 5 and 125 psig (35 kPa and 860 kPa).

Other Options

• Capacity Dampers and Controls
• Pony Motors
• Ladders
• Stainless Steel Fan Shafts
• Tapered Discharge Hoods
• Solid Bottom Panels
• Heater Control Packages
• Hot Water or Steam Coils
• Steam Injectors
• Bottom Suction Connections
• Vibration Switches
• Remote Sump Connections
• Motors– Energy Efficient / 2S/1W and 2S/2W / Mill and Chem Duty
  Automotive Duty and Many More, Consult the Factory

SECTION 23 65 00 - FACTORY-FABRICATED COOLING TOWERS PART 1 - GENERAL 1.1 RELATED DOCUMENTS

A. Drawings and general provisions of the Contract, including General and Supplementary Conditions and Division 1 Specification Sections, apply to this section.

1.2 SUMMARY:

A. This Section includes factory assembled and tested, open circuit, forced draft counterflow cooling tower. 1

.3 SUBMITTALS A. General. Submit the following:

1. Certified drawings of the cooling tower, sound data, recommended steel support indicating weight loadings, wiring diagrams, installation instructions, operationand maintenance instructions, and thermal performance guarantee by the manufacturer.

1.4 QUALITY ASSURANCE A. Verification of Performance:

1. Test and certify cooling tower thermal performance according to CTI Standard 201.

2.Test and certify cooling tower sound performance according to CTI ATC-128. B. Meet or Exceed energy efficiency per ASHRAE 90.1.

1.5 WARRANTY

A. Motor/Drive System: Five (5) year comprehensive warranty against materials and workmanship including motor, fan, bearings, mechanical support, sheaves, bushings and belt.

B. Unit: One (1) year from start-up, not to exceed eighteen (18) months from shipment on the unit.

PART 2 - PRODUCTS

2.1 MANUFACTURERS

A. Manufactures: Subject to compliance with requirements, provide cooling towers manufactured by one of the following:

1. EVAPCO, Inc.

2. Approved Substitute

2.2 MATERIALS

A. Galvanized Sheet Steel complying with ASTM A 653/A 653M and having G-235 designation.

B. Optional Type 304 and/or 316 Stainless Steel as specified.

2.3 FORCED-DRAFT, COUNTERFLOW COOLING TOWERS

A. Description: Factory assembled and tested, forced draft counterflow cooling tower complete with fill, fan(s), louvers, accessories, and rigging supports.

B. Cooling Tower Characteristics and Capacities: Refer to the Cooling Tower schedule.

C. Fan(s):

1. Type and Material: forward curved, centrifugal of hot-dipped galvanized construction. The fans shall be factory installed, and statically and dynamically balanced for vibration free operation.

2. Fan Housing: The complete drive system, including the electric motor, belts, bearings, fan, and drives shall be completely enclosed in a protective housing which covers the drive system and provides sound reduction.

3. Maximum sound pressure level of _____dB(A) measured at 5 feet above the fan discharge during full speed operation in accordance with CTI Standard ATC-128.

D. Water Distribution System: Non-corrosive materials.

1. Evenly distribute of water over fill material with pressurized spray tree. a. Pipes: Schedule 40 PVC, Non-corrosive Materials b. Nozzles: Non-clogging, ABS Plastic, threaded into branch piping.

2. Maximum pressure at inlet shall be ____ psig.

E. IBC Compliance: The unit structure shall be designed, analyzed, and constructed in accordance with the latest edition of the International Building Code (IBC) Regulations for seismic loads up to _____ g and wind loads up to __ psf.

F. Collection Basin Material: Heavy Gauge G-235 Galvanized Steel or Type 304 Stainless Steel (Optional) for long life and durability:

1. Removable Type 304 Stainless Steel strainer with openings smaller than nozzle orifices.

2. Joints: Bolted and sealed watertight.

3. Overflow, Makeup and Drain connections: G-235 Galvanized Steel (MPT).

4. Outlet Connection: G-235 Galvanized Steel Beveled for weld and grooved for mechanical coupling.

G. Casing: Heavy Gauge G-235 Galvanized Steel or Type 304 Stainless Steel (Optional):

1. Casing panels shall totally encase the fill media to protect the fill from damage due to direct atmospheric exposure. All galvanized steel panel edges shall be coated with a 95% pure zinc compound during fabrication.

2. Fasteners: Corrosion resistance equal to or better than materials being fastened.

3. Joints: Sealed watertight.

4. Welded Connections: Continuous and watertight

H. Fill Media: PVC; resistant to rot, decay and biological attack; formed, crossfluted bonded together for strength and durability in block format for easy removal and replacement; suitable for use as a working surface; self extinguishing with flame spread rating of 5 per ASTM E84-81a; able to withstand continuous operating temperature of 130°F; and fabricated, formed and installed by the manufacturer to ensure water breaks up into droplets.

I. Drift Eliminators: Same material as Fill. 0.001% drift rate.

J. Protective Air Inlet Screens: Galvanized Steel

K. Water Level Control: Brass mechanical makeup water valve and plastic float with an adjustable linkage.

2.4 MOTORS AND DRIVES

A. General requirements for motors are specified in Division 23 Section "Motors".

B. Enclosure Type: TEFC

C. Motor Speed: Single Speed (Option: VFD Duty, 2-speed)

D. Drive: Power Band Belt designed for 150% of the motor nameplate HP.

1. Belt: V-belt type neoprene.

2. Sheaves: Aluminum alloy, taper lock design.

3. Bearings: Heavy duty, self-aligning bearings with extended grease lines and fittings

4. Fan Shaft: Solid steel shaft with forged bearing journals.

5. Vibration Cutout Switch: Mechanical switch to de- energize fan motors if excessive vibration in NEMA 4 enclosure.

2.5 MAINTENANCE ACCESS

A. Access Door: A circular access door shall be located above the basin to allow for easy access to the pan interior.

B. Ladders: Aluminum, vertical complying with 29 CFR 1910.27.

2.6 SOUND ATTENUATION

A. Inlet Attenuation: Self supporting, materials to be same as fan section. Baffled panels shall change the path of air entry and capture radiated noise. External belt adjustment and lubrication points shall be provided.

B. Discharge Attenuation: Straight sided discharge hood with insulated baffles to reduce the overall sound level of the discharge air. A large access panel to allow access to the water distribution system and drift eliminators shall be provided. 

Sound Attenuation Packages

The centrifugal fan design of the LSTE models operate at lower sound levels, which make these units well suited for sound sensitive applications. If the standard LSTE and LPT sound pressure level is not quiet enough for certain applications, the sound levels can be further reduced by adding various stages of sound attenuation. Consult the factory for Factory Certified Sound Data for each option. Please refer to Evapco’s selection software for correct model number designation and CTI Certified performance

Inlet Attenuation

Reduces sound radiated through the end and side air intakes. It consists of baffled panels to change the path of the air entry and to capture the radiated noise thus reducing the overall sound levels generated. In addition, the external belt adjustment mechanism is extended through the inlet attenuator to allow easy belt adjustment without having to enter the unit.

Discharge Attenuation

The discharge attenuation hood features a straight sided design with insulated baffles to reduce the overall sound levels of the discharge air. The discharge attenuation incorporates a large access panel to allow entry to the drift eliminators and water distribution system. If a higher discharge velocity is required with minimal sound attenuation, a tapered discharge hood is available.

Thermal Performance

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