Closed Circuit Coolers

evapco distributed by Clark Johnson Co
eswb ciricuit cooler clark johnson company

ESWB Closed Circuit Coolers

The ESWB is an induced draft, counterflow design closed circuit cooler with a CTI Certified capacity range of 583 to 7264 MBH (171 to 2129 kW). Standard construction includes the patented, high efficiency Sensi-Coil® Technology featuring CrossCool™ Internal Tube Enhancement , EVAPAK Fill and G-235 (Z725-Europe) galvanized steel casing and basin. Type 304 stainless steel construction is available for the basin, the redistribution basin, or the entire unit.

   Design Features

     Maintenance Features

      Drive Systems

      Optional Equipment

Thermal Performance

ESWB Closed Circuit Cooler - Design Features


The ESWB stands apart as being the most energy efficient and the quietest axial fan closed circuit cooler on the market today. The ESWB is able to provide superior performance as a result of its full footprint patented Sensi-Coil® Technology. The Sensi-Coil® now features CrossCool™ Internal Tube Enhancement which increases the internal heat transfer coefficient of the coil and thus increases the cooling capacity of the unit.


The ESWB’s Cooling Technology Institute † certified performance, new owner oriented features and independent certification of the International Building Code (IBC) compliance reinforce the ESWB’s position as a premier cooler in the HVAC industry.






Principle of Operation Evapco was the first to develop a closed circuit cooler with Patented Optimized Technology. The pump is energized, and water is circulated up to the water distribution system. This starts with the large orifice EvapJet nozzles evenly distributing water as a thin film over the extended fill surface for maximum cooling efficiency. The fan system operates simultaneously, moving large volumes of air through the unit in a direction opposite the falling water. The air and water contact directly across the fill surface whereupon a small portion of the spray water is evaporated. The warm and saturated air is then discharged from the unit dissipating heat to the atmosphere. The spray water exits the fill section as a cooled fluid where it is collected by the redistribution basin for even soaking of the full footprint coil. The hot process fluid enters the coil through the bottom coil connection(s). The heat load is rejected to the circulating water that cascades over the coil surface by means of sensible heat transfer.       Efficient Drift Eliminators The eco-ATWB-H is equipped with an efficient drift eliminator system that effectively reduces entrained water droplets from the air discharge to less than 0.001% of the spray water flow rate. The eliminators are constructed of non-corrosive PVC with a multi-pass design for maximum drift reduction. They are assembled in modular sections for easy removal and access to the water distribution system. In addition to reducing drift, the eliminators also function as effective debris screens which protect the spray system from sunlight and debris.   Superior Air Inlet Louver and Screen DesignThe air inlet louver screens on the eco-ATWB-H are constructed of corrosion-free PVC. They are a two pass design that minimizes splashout and reduces the potential for algae formation inside the cooler. In single pass louver systems used by other manufacturers, circulating water droplets tend to splashout, especially when the fans are shut off. With the two pass louver system, the water droplets are captured on the inward sloping pass, minimizing splashout problems. This unique louver design completely encloses the basin area. Direct sunlight is blocked from the water inside the cooler, thereby reducing the potential of algae formation. Water treatment and maintenance costs are substantially reduced. While effectively containing the recirculating water and blocking sunlight, the louver design has a low pressure drop. The low pressure drop results in lower fan energy consumption, which reduces the operating costs of the cooler. Patented EVAPAK® Fill The patented EVAPAK® fill is specially designed to induce highly turbulent mixing of the air and water for superior heat transfer. The fill-pack is constructed of polyvinyl chloride (PVC) sheets which are thermally formed into a cross flute design. The individual fill sheets are bonded together to form rigid fill blocks. The fill blocks are then stacked within the unit's protective casing. The structural strength of the assembled fill deck enables it to be used as a working platform. EVAPAK® fill is impervious to rot and decay, and is self-extinguishing with a flame spread rating of 5 per ASTM Standard E84.  Patented Sensi-Coil® Technology   (US Patent #7,296,620)The Sensi-Coil®, exclusive on the ESWA closed circuit cooler, features the maximum amount of Thermal-Pak elliptical tubes packed closely together in a coil arrangement designed with over 20% additional coil surface area. EVAPCO's coils are manufactured within the most stringent of quality control procedures. Each circuit consists of high quality steel tubing formed into a continuous serpentine circuit. Each circuit is then inspected and tested prior to being welded into a framed coil assembly. The coil assembly is then pneumatically tested at 400 psig under water to ensure its integrity. The entire coil assembly is then hot-dip galvanized for industrial strength corrosion protection. Now EVAPCO offers the TITAN COIL. Manufactured from type 304L Stainless Steel, the TITAN COIL is manufactured using Evapco's patented elliptical tube Sensi-Coil ®design upgraded to Xtra Tough construction featuring: Xtra Durability, Xtra Corrosion Resistance, and an Xtra long 5 YEAR coil warranty as standard..    Maintenance Free ZMII®  Water Distribution System    EVAPCO’S Zero Maintenance ZMII® Spray Nozzle remains clog-free while providing even and constant water distribution for reliable, scale-free evaporative cooling under all operating conditions. The heavy duty nylon ZMII® Spray Nozzles have a 1-5/16” diameter opening and a 1-1/2” splash plate clearance enabling EVAPCO to use 75% fewer nozzles. Furthermore, the fixed position ZMII® nozzles are mounted in corrosion-free PVC water distribution pipes that have threaded end caps. Together, these elements combine to provide unequaled coil coverage and scale prevention, and make the industry’s best performing non-corrosive, maintenance-free water distribution system.  The water distribution is designed to provide a minimum 6 GPM over each square foot (4 liters per second over each square meter) of unit plan area to ensure proper flooding of the coil.Principle of OperationEfficient DriftEliminatorsSuperior Air Inlet Louver and Screen DesignEVAPAK FILLPatented Sensi CoilWater Distribution



ESWB Closed Circuit Cooler - Maintenance Features


Designed for easy maintenance, the ESWB Closed Circuit Cooler leads the industry in service friendly features. The three most critical areas for closed circuit cooler maintenance are the basin, drive system, and coil. The ESWB basin section is designed to allow quick and easy access from outside the cooler. Just like the basin, all service to the drive system can be safely performed from the side of the cooler, and EVAPCO's Power-Band drive system is the easiest belt drive system to maintain in the industry! The exclusive Thermal-Pak® Coil is designed for trouble-free maintenance and long life straight from the factory.




ESWB Closed Circuit Cooler - Drive Systems


The ESWB Closed Circuit Cooler is an Advanced Technology, induced draft counterflow design closed circuit cooler featuring EVAPCO's patented Sensi-Coil® technology - the most efficient in the industry. The counterflow design provides the ESWB Closed Circuit Cooler with inherently better operational and maintenance features. The ESWB is now standard with CTI Certified Performance including the Super Low Sound Fan option.




  •     Fan Motors
  •     Fan Shaft Bearings
  •     Drive System Sheaves
  •     Power-Band Belt Drive


Fan Motors


 Closed Circuit Cooler models utilize heavy duty totally enclosed (T.E.F.C. or T.E.A.O) fan motors designed specifically for closed circuit cooler applications. In addition to the standard motors offered on each cooler, EVAPCO offers many optional motors to meet your specific needs, including:


  • Premium Efficiency Motors
  • Multi-Speed Motors
  •  Inverter-Duty Motors for VFD Applications


for VFD Applications 8.5' (2,6 m) wide ESWA models feature T.E.F.C. motors are located on the outside of the unit, protected by a hinged, swing away cover. 12' (3,7 m) wide ESWA models have T.E.A.O. motors located inside the fan section on a heavy duty motor base which swings to the outside for repair or removal.







Fan Shaft Bearings


The fan shaft bearings on the Closed Circuit Cooler are specially selected to provide long life, minimizing costly downtime. They are rated for an L-10 life of 75,000 to 135,000 hours, making them the heaviest duty pillow block bearing in the industry used for Closed Circuit Cooler duty.


Power-Band Belt Drive


The Power-Band drive is a solid-back multigroove belt system that has high lateral rigidity. The belt is designed for closed circuit cooler service, and is constructed of neoprene with polyester cords. The drive belt is sized for 150 percent of the motor nameplate horsepower ensuring long and trouble free operation.




Drive System Sheaves


Drive system sheaves located in the warm, moist atmosphere inside the cooling tower are constructed of an aluminum alloy. Those located externally are protected by a hinged cover.

Optional Equipment


The standard design of the EVAPCO eco-ATWB  provides the customer with the most efficient and easiest Closed Circuit Cooler to maintain in the industry. There are additional options which can make maintenance easier, extend the life, or enhance the performance capabilities of the Closed Circuit Cooler.



  • Sloped Access Ladders
  • Stainless Steel Water Basin
  • Electric Water Level Control
  • Electric Immersion Heaters
  • Remote Sump Configuration
  • Low Sound Solutions
  • Pulse~Pure® Water Treatment System

Clark Johnson Company, Inc.       2016