ATWB Closed Circuit Cooler

The original Advanced Technology closed circuit cooler provides an induced-draft, axial fan solution for a wide array of cooling applications.

Bringing EVAPCO's Advanced Technology design to closed circuit coolers, the ATWB features the Thermal-Pak II® Coil with CrossCool™ Internal Tube Enhancement, offering incredible evaporative cooling capacity using its advanced counterflow design.

  • Available in a huge range of models and box sizes unparalleled in the industry
  • Ranging in capacity from 91 to 37,765 MBH
  • IBC Compliant – Independently certified by the International Building Code to withstand seismic and wind load forces in North America; available with IBC Upgraded Structural Design to meet the strictest of building requirements
  • Independently certified by the Cooling Technology Institute
  • Available with FM Approved Construction

ATWB_PofOThe process fluid enters the Thermal-Pak II coil through the top coil connection and circulates through the coils. The water distribution system cascades water over the tubes of the coil, transferring heat to the water. Air is drawn upward and over the coils by the axial fan, agitating the falling water and increasing the transfer of heat. A small amount of the recirculating water evaporates due to latent heat transfer through the tube and fin walls of the Thermal-Pak II coil, removing heat from the system. The cooled fluid then returns to the process via the bottom coil connection.

Thermal-Pak II Coil

EVAPCO's Thermal-Pak II coils patented design assures maximum cooling capacity. The airflow through the coil is counterflow to the fluid flow, providing the most efficient heat transfer process. A special coil design is utilized to reduce the air pressure drop through the unit while maximizing tube surface area and increasing its heat transfer capabilities.

  • Elliptical return bends allows for more circuits per coil bundle increasing the maximum capacity per footprint
  • Coil located in airstream increasing dry bulb switchover temperature
  • CrossCool Internal Tube Enhancement increase fluid turbulence providing additional evaporative capacity
  • Available in type 304 SS or type 316 SS construction
Drift Eliminators
  • Limits the drift rate to less than 0.001% of the recirculating water rate
  • Limit the potential of spreading Legionella
  • Constructed of an inert polyvinyl chloride (PVC)
Superior Air Inlet Louver and Screen Design
  • Constructed of an inert polyvinyl chloride (PVC)
  • Two pass design that minimizes splash-out and the potential for algae formation inside the tower
  • Framed in steel in easily removable sections
Pressurized Water Distribution System

EVAPCO's Zero Maintenance ZMII® spray nozzle remains clog free while providing even and constant water distribution, providing the industry's best performing non-corrosive, maintenance-free water distribution system.

  • ZMII spray nozzles have a 1-1/4" diameter opening and a 1-1/4" splash plate clearance
  • Mounted in corrosion-free PVC water distribution pipes that have threaded end caps
  • Provides unequaled coil coverage and scale prevention
Stainless Steel Water Touch Basin
  • Available in Type 304 or Type 316 Stainless Steel
  • Includes the entire basin area including the support columns and the louver frames
  • Welded basin seams for leak-free operation
Stainless Steel Casing & Fan Section
  • Available in Type 304 or Type 316 Stainless Steel
  • Includes the entire upper section including fan guard
Sound Sensitive Installations

Available with multiple equipment options to reduce the overall sound generated from the side or top of the unit.

  • Super Low Sound Fan
  • Low Sound Fan
  • Water Silencers
  • Discharge Attenuation
  • Offset Sound Attenuation Walls
FACTORY-MOUNTED Water Treatment Systems

Available with FACTORY-MOUNTED water treatment systems, providing environmentally sensitive alternatives for treating water in evaporative cooled equipment.

  • SmartShield solid chemical water treatment system
  • Pulse-Pure CHEMICAL-FREE water treatment system
Maintenance Accessories

Available with multiple equipment options to aid in the maintenance of the closed circuit cooler.

  • External service platform
  • Basin level platform
  • Sloped ladder
  • Hinged louver access door
  • Motor davit with base
Document Categories
Product Model filter

Drawing Types
Media name Drawing Type Drawing Format Product Model
ATWB 9-7J8-Z Unit Certified (English) Unit Certified Print (.pdf) ATWB 9-7J8-Z
ATWB 9-7J8-Z Unit Certified (Metric) Unit Certified Print (.pdf) ATWB 9-7J8-Z
ATWB 9-7J8-Z Unit Certified (Metric) Unit Certified Print (.pdf) ATWB 9-7J8-Z
ATWB 9-7J9 CAD Drawing CAD Drawing CAD Drawing (.dwg) ATWB 9-7J9
ATWB 9-7J9 CAD Drawing CAD Drawing CAD Drawing (.dwg) ATWB 9-7J9
ATWB 9-7J9 REVIT REVIT Revit (.zip) ATWB 9-7J9
ATWB 9-7J9 REVIT REVIT Revit (.zip) ATWB 9-7J9
ATWB 9-7J9 Steel Support (English) Steel Support Print (.pdf) ATWB 9-7J9
ATWB 9-7J9 Steel Support (English) Steel Support Print (.pdf) ATWB 9-7J9
ATWB 9-7J9 Steel Support (Metric) Steel Support Print (.pdf) ATWB 9-7J9