LRW-H Hybrid Closed Circuit Cooler

Technical Data

• Unit:  Hybrid closed circuit cooler
• Models:   
• Width:   
• Design:    Forced draft
• Capacity:   
• Air Flow:
• Fan:    Centrifugal
• Drive:    Belt driven

Properties 

• WATER SAVINGS up till 60%
• Low height
• low sound
• Improved corrosion protection, standard stainless steel sump
• Indoor installation possible
   
• Plume reduction

WATER SAVINGS up till 60%

The high performance 8-Row dry 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!!!

Low height

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.

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.

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.

Plume reduction as per standard

The 8-row dry 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 reduce. 

The process fluid is circulated first through the high performance, 8-row, copper/marine-alloy aluminum dry coil before entering the evaporative coil of the standard LRW closed circuit cooler. Heat from the process is dissipated from both dry and wet coil tubes. Simultaneously, air is forced upward, over the coil opposite the water flow of the evaporative section. A small portion of the water is evaporated which removes latent heat. The warm moist air then passes over the dry coil removing sensible heat. The relative humidity of the discarge air reduces before it is discharged to the atmosphere. 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-H 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.

Split fan-housing

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.

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 Zero-Maintenance spray nozzles

The ZM (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.