Closed Circuit Coolers

LSWA Closed Circuit Cooler

LSWA Closed Circuit Cooler

Forced draft centrifugal fan counterflow closed circuit cooler. The LSWA cooler is used for cooling of water or water/glycol mixtures. The process fluid remains without oxygen and impurities. Executed as per standard with Z-725 (725 g/m² zinc) galvanized steel panels.

An LSWA cooler is the ideal solution for sound-sensitive installations due to the centrifugal fan with forward curved fan blades to allow static pressure for the installation of sound-attenuators.

EVAPCO's Thermal-Pak® coils feature a patented design which assures maximum cooling capacity. The elliptical tubes of the coil are staggered in the direction of airflow to obtain a high heat exchange coefficient. The coils are manufactured from high quality steel tubing following the most stringent quality control procedures. The assembled coil is pneumatically tested under water in accordance with the European Pressure Equipment Directive (PED) 97/23/EC.

Evapco Europe provides with each closed circuit cooler a Thermal Performance Guarantee. LSWA-units are constructed for maximum nominal capacity of 2,7 MW.

Long-lasting corrosion protection is guaranteed with Z-725 heavy gauge mill hot-dip galvanized steel (Z-725 = 725 g/m² zinc). The galvanized steel construction withstands the most difficult environmental and operating conditions.

For special applications, Evapco can produce the units with stainless steel sump, with a water touched stainless steel construction or a complete stainless steel construction (AISI 304 or 316 are possible).

Technical Data 

  • Unit:    Closed circuit cooler
  • Models:    50 Models (Type LSWA 20AA till LSWA 348D)
  • Width:    1.235 / 1.664 / 2.388 / 2.991 mm
  • Design:    Forced draft
  • Capacity:    73 till 2.673 kW
  • Air Flow:    5,5 till 106,0 m³/s
  • Fan:    Centrifugal
  • Drive:    Belt driven


  • Easy rigging
  • Small footprint
  • Low sound
  • Anti-Fog coils as an option
  • Indoor installation possible
  • Dry operation possible

NEW: Easy rigging

A new field assembly seam design which ensures easier assembly and reduced potential for field seam leaks. Self-guided channels guide the fan casing section easily into position improving the quality of the field seam and eliminates up to 66% of fasteners.
Furthermore is the ease of mounting ductwork, discharge hood and attenuation enhanced by the full integration within the casing section of the eliminators.

Small footprint

The LSWA cooler range is designed to minimize the cooling tower footprint. The fan is installed underneath the fill section and not besides it like for the LR-style cooling equipment. Low occupation of ground surface (footprint) is sometimes required when limited equipment area is available.

Low sound

The standard installed forward curved centrifugal fan has a natural low sound emission. Installation of an inlet attenuator will reduce the dominant fan-noise significantly. Additional reductions can be established by installing outlet sound attenuators, these will further reduce the sound emmision of the fan but also of the spray system.

Anti-Fog coils as an option

To reduce the typical cooling tower plume during evaporation of warm water in the airflow, an anti-fog coil can be installed on top of the equipment. By heating up the leaving air before it mixes with the ambient air above the cooling tower, a plume reduction will be the result. Evapco can offer 2 or 3-row copper/aluminum anti-fog coils. See also LSWA-H for high efficiency anti-fog coils with inherent water saving properties.

Indoor installation possible

Indoor installation often require ducting from the cooling tower to the building. By increasing the motor size of the centrifugal fan, additional external static airpressure can be accepted without thermal performance loss.

Dry operation possible

The Evapco Thermal-Pak™ coil is designed for optimized evaporative cooling. But when the cooling load is variable, dry operation might be possible during cold-weather periods. The available dry heat exchange surface is often large enough to cover the heatload during wintertime. Dry operation reduces the water consumption but also creates time for regular cleaning of the sump. This is an important advantage in relation to the avoidence of LD.

The process fluid is circulated through the coil of the closed circuit cooler. Heat from the process is dissipated through the coil tubes to the water cascading downward over the tubes. Simultaneously, air is forced upward, over the coil opposite the water flow by the fans. A small portion of the water is evaporated which removes the heat. The warm moist air is discharged to the atmosphere while the circulation water drains to the basin at the bottom of the cooler where it is recirculated by the pump up through the water distribution system and back down over the coils. The vertical air discharge of the LSWA design and the distance between the discharge air and the fan intake reduce 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.

1. Casing and basin design

High Performance drift eliminators
Certified in accordance with Eurovent OM-14-2009 

The drift eliminators remove entrained water droplets from the air stream to limit the drift rate to less than 0.001% of the recirculating water rate. The unit can be located in areas where minimum water carryover is critical. The drift eliminators are constructed of an inert polyvinyl chloride (PVC) plastic material which effectively eliminates corrosion of these vital components. They are assembled in sections to facilitate easy removal for inspection of the water distribution system.
New: The eliminators are now fully integrated within the casing section for easy mounting of ductwork, discharge hood and attenuation.

Z-725 Galvanized steel panels 

EVAPCO has developed the ultimate system for corrosion protection in galvanized steel construction - the EVAPCOAT Corrosion Protection System. Z-725 is the heaviest level of galvanizing available for manufacturing evaporative condensers and has a minimum of 165% more zinc protection than competitive designs using Z-275 steel.

2. Heat transfer system

Thermal-Pak® evaporative coil

EVAPCO’s patented Thermal-Pak® condensing coils feature a design which assures maximum condensing capacity. The airflow thru the coil is counterflow to the refrigerant flow, providing the most efficient heat transfer.This 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. The uniquely elliptical shaped tubes of the coil are staggered in the direction of air flow to obtain a high film coefficient. In addition, all tubes are pitched in the direction of refrigerant flow to give good drainage of liquid refrigerant. The coils are manufactured in accordance with Pressure Equipment Directive “PED” 97/23/EC. High quality steel tubing is used following the most stringent welding and quality control procedures. Each circuit is inspected to assure the material quality and then tested before being assembled into a coil. Finally, the assembled coil is air pressure tested under water at the appropriate pressure, in accordance with the Pressure Equipment Directive. To protect the coil against corrosion, it is placed in a heavy-duty steel frame and the entire assembly is hot dip galvanized at a temperature of approximately 430°C.

3. Mechanical design

Centrifugal fan

Statically and dynamically balanced galvanized centrifugal fans with forward curved fan blades. The centrifugal fans allow static pressure to be added to the unit for installation of attenuators, anti-fog coils, ducts, etc...

Single speed fan motor 

Each Evapco unit is equipped as per standard with a heavy duty, single speed IP55 TEFC / TEAO electrical motor.

4. Water distribution

Spray pump

The spray pump is optimized for high waterflow at relative low pressure. The motor is totally enclosed and protected with an end-cap to ensure a long trouble free operation.

Spray-water distribution system 

The water distribution system is enclosed and completely protected by the casing panels and drift eliminators. The water distribution system is made with non-corrosive materials including schedule 40 PVC pipe and durable ABS plastic nozzles. The spray branch piping is easily removed and designed with threaded end-caps for easy cleaning. Evapco’s design avoids the problems of biological growth and clogging.

ZM II Zero-Maintenance spray nozzles

The ZM II (Zero Maintenance) nozzle is constructed of heavy duty nylon for corrosion resistance and long operating life. Zero maintenance is made possible with large 33 mm diameter openings and a clearance of 38 mm between the nozzle opening and water diverter plate. This allows the largest debris to flow easily through the ZM spray nozzle. Evapco’s design avoids the problems of biological growth and fouling that can occur to a water distribution system.

5. Maintenance and inspection

NEW: Sloped basin

A completely sloped basin allows the water to be drained from the basin. Debris can be easily flushed out through the drain and this helps to prevent buildup of sedimentary deposits, biological fouling and minimizes standing water.

Round access door

The circular access door is provided to allow access to the basin. All float-valve and strainer assemblies are located near the door for easy adjustment and cleaning.

6. Operational control

Mechanical water level control

Simple but reliable water level control system with adjustable mechanical float and brass float-valve.