LRW-H Hybrid Closed Circuit Cooler
Forced draft centrifugal fan counterflow closed circuit cooler for combined wet/dry operation. The LRW-H cooler is used for cooling of water or water/glycol mixtures when reduced cooling tower height is required. The process fluid remains without oxygen and impurities and due to the ARID Fin-Pak dry cooling coil installed in series with the evaporative coil, water savings up till 60% can be established. As a consequence less water treatment chemicals are necessecary and visible plume is completely eliminated during dry operation. During wet operation the plume is reduced or completely eliminated. Executed as per standard with Z-725 (725 g/m² zinc) galvanized steel panels.
An LRW-H 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.
The dry coil is constructed with copper tubes and aluminum-magnesium fins for heavy duty application. Fin thickness and fin spacing are optimised to avoid fowling and allow easy cleaning. Thanks to the
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.
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: Hybrid closed circuit cooler
- Models: 91 Models (LRW-H 3-2E6 to LRW-H 8-7P12)
- Width: 1.029 / 1.540 / 2.388 mm
- Design: Forced draft
- Air Flow: 3.4 to 29.2 m³/s
- Fan: Centrifugal
- Drive: Belt driven
- WATER SAVINGS up till 60%
- Less water treatment chemicals
- Plume reduction/elimination
- Low height
- Low sound
- Improved corrosion protection, standard stainless steel sump
- Indoor installation possible
WATER SAVINGS up till 60%
The high performance ARID Fin-Pak dry cooling coil installed in series with the evaporative coil will reject a significant amount of heatload into the airflow coming from over the evaporative coil. Depending on the typical load-profile, water cost, energy cost, climatical conditions and concentration factor, EVAPCO can provide a detailed operating cost calculation. A comparison can be made with a standard evaporative cooler. This comparison will result in an accurate calculation of the OPERATING COST SAVINGS. Using the appropriate capacity control, SAVINGS UP TO 60% are no exception!!!
Plume reduction as per standard
The ARID Fin-Pak dry cooling coils for water saving serves double purpose as an anti-fog coil as well. By heating up the leaving air before it mixes with the ambient air above the cooler, visible plume formation is significantly reduced and completely eliminated during dry operation.
The LRWH Wet/Dry cooler range is designed to minimize the cooling tower 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.
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.
Water Efficient Mode
(Evaporative and Sensible Heat Transfer)
The joint wet and dry operation mode provides water savings as well as plume reduction. In this joint mode of operation, the fan is on and the process fluid enters the dry coils through the top coil connections in the discharge hood (Fan on, Spray Pump on). The Dry Coil rejects a portion of the heat load to the atmosphere through the tube and fin walls to the air passing over the coils using sensible heat transfer. The spray pump is energized where heat from the process fluid is transferred through the coil tubes to the water cascading downward over the Evaporative Coil. This mode of operation minimizes the amount of water used while maintaining the cooling capacity required. Plume reduction can also be achieved in the mode as the hot saturated discharge air is heated and dried as it passes over the Dry Coil located in the discharge hood.
(Sensible Heat Transfer)
In the dry mode, the recirculating pump is deenergized (Fan on, Pump off). The process fluid enters the dry coils through the top coil connections in the discharge hood with the Fan on. Heat from the process fluid is dissipated to the atmosphere by sensible heat transfer through the tube walls to the air passing over the Evaporative and Dry Coils. The process fluid then returns to the heat source via the bottom coil connection. This mode of operation eliminates water consumption as well as plume when the dry bulb temperature is favorable.
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. LS-style units require the split fan housing when fan replacement is not possible from the sides.
Stainless steel sump
To improve the corrosion resistance, the sump will be executed in stainless steel AISI304. This option is standardized for LR-style units. Upgrades to AISI316 are possible.
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.
ARID Fin-Pak dry cooling coil
The ARID Fin-Pak Dry Cooling Coil is installed in the air discharge of the closed circuit cooler and it should be piped in series with the wet coil. The ARID Fin-Pak Dry Cooling Coil is constructed of copper tubes with tubular copper headers. The fins have fully drawn collars to maintain consistent fin spacing and continuous surface contact over the entire tube. To maximize heat transfer the fins are made of Aluminum/Magnesium alloy to have a good corrosion resistance. The coils are placed in a heavy-duty galvanized Z-725 frame. The frame has full collars to support the coil correctly and avoid damaging the tubes. The dry coils are pneumatically tested under water at 16 barg. The tubes and frame are available in stainless steel 304L/316L as an option.
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.
ZMII Zero-Maintenance spray nozzles
The ZMII (Zero Maintenance) nozzle is constructed of heavy duty nylon for corrosion resistance and long operating life. Zero maintenance is made possible with large 41mm diameter openings and a clearance of 38mm 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. ICT units have round doors to allow access in the fan plenum.
6. Operational control
Mechanical water level control
Simple but reliable water level control system with adjustable mechanical floadbal and brass float-valve.