LRW Closed Circuit Cooler
Forced draft centrifugal fan counterflow closed circuit cooler. Executed as per standard with Z-725 (725 g/m² zinc) galvanized steel casing. The LRW cooler is used for cooling of water or water/glycol mixtures. The process fluid remains without oxygen and impurities.
An LRW 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. LRW-units are constructed for maximum nominal capacity of 0,6 MW.
Long-lasting corrosion protection is guaranteed with a 304L stainless steel basin up to overflow and 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 a water touch stainless steel sump, with a water touched stainless steel construction or a complete stainless steel construction (AISI 304 or 316 are possible).
- Unit: Closed circuit cooler
- Models: 38 Models (Type LRW 18-2E till 96-6N)
- Width: 1.029 / 1.540 / 2.388 mm
- Design: Forced draft
- Capacity: 43 till 580 kW
- Air Flow: 3,9 till 28,5 m³/s
- Fan: Centrifugal
- Drive: Belt driven
- Low height
- Low sound
- Indoor and Top-Top execution possible
- Dry operation possible
The LRW cooler range is designed to minimize the closed circuit cooler height. The fan is installed besides the fill section and not underneath it like for the LS-style cooling equipment. Low equipment height is sometimes required for architectural and/or esthetical reasons.
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.
The LRW unit has been designed to satisfy installation requirements where height limits must be observed. The lower profile design of the LRW does not, however, sacrifice maintenance accessibility for reduced height. Its unique casing design allows the water distribution system, cold water basin, fan section and other unit components to be easily maintained. Small, light weight sections of the drift eliminators can be easily removed to access the water distribution system. Large circular access doors are located on both sides of the cold water basin to allow adjustment of the float assembly, removal of the stainless steel strainers and cleaning of the basin. The fan motor and drive system are located at one end of the unit and are completely accessible by removing the inlet screens. Although, routine maintenance can be performed from the exterior of the unit without removing the inlet screens.
Indoor and Top-Top execution 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. The standard LR-type unit has a horizontal air intake and a vertical air outlet. If vertical air inlet and outlet is required, Evapco will modify the inlet plenum around the fan to establish the optional Top-Top execution. To avoid recirculation, a section with guiding vanes over the entire surface of the air outlet is included in the Top-Top option.
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 LRW 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
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.
This option makes it possible to replace the fan from the air-intake side of the unit. Split-fan housing is standardized for the LR-style units and optional for LS-style equipment.
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 250 % 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
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
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
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.