Evaporative Condensers

PMCQ Evaporative Condenser

PMCQ Evaporative Condenser

Forced draft axial fan counterflow evaporative condenser for industrial refrigeration applications. Executed as per standard with Z-725 (725 g/m² zinc) galvanized steel panels.

A PMCQ condenser is the ideal solution for industrial installations. The PMCQ design combines low energy consuming axial fans with high performance counterflow heat exchange.

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.

The PMCQ condenser range is complient with the International Building Code (IBC). Evapco provides with each cooling tower a Thermal Performance Guarantee. PMCQ-units are constructed for maximum nominal capacity of 7,6 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:     Evaporative Condenser
  • Models:     84 Models ( Type PMCQ-316 till PMCQ-1786 )
  • Width:      2.991 / 3618 mm
  • Design:     Forced draft
  • Capacity:     1358 till 7679 kW
  • Air Flow :     25 till 131 m³/s
  • Fan:     Super Low Sound Axial
  • Drive:      belt driven

Properties

  • Super Low Sound
  • Easy to install
  • Easy to maintain
  • Energy Saving

Super low sound emission

The PMCQ evaporative condensor is per standard equiped with one piece molded heavy duty FRP SUPER LOW SOUND FANS. This results in sound reductions from 10 till 13 dB(A) at 15 m from the fan side.

Easy to install

The PMCQ features a new field seam design which ensures easier assembly and fewer field seam leaks. The field seam incorporates new self-guiding channels to guide the fill section into position and set in place on the bottom fan section of the tower. In addition, the new design eliminates up to 85% of the fasteners typically used to join the sections in the field significantly reducing the contractor labor costs for installation.

Easy to maintain

The PMCQ-design is optimized for easy access to all critical locations and components. The oversized access door enables maintenance personnel to quickly and easily enter the sloped basin. The drive components of the PMCQ are easily accessed for routine maintenance from the front of the unit.

Energy saving

The energy consumption of the PMCQ evaporative condensor is minimized due to the optimal heat exchange and the application of axial fans. The heat exchange efficiency of counterflow condensor is the highest achievable compared to cross-flow and parallel flow heat exchange. On top of the efficiency advantage, it is generally known that axial fans consume on average more than 50% less motor-power than centrifugal fans. The result is an overall optimized and low engergy consumption.

The refrigerant gas is discharged from the compressor into the inlet connection of the evaporative condenser. Water from the condensor's sump is continuously flooded over the condenser coil, while ambient air is simultaneously forced intor the unit. As the ambient air moves up through the coil section, a portion of the spray water is evaporated into the air stream.

The evaporative process cools the spray water, which in turn cools the tubes containing the refrigerant gas. The cool tube walls cause the refrigerant gas to give up heat and condense into a liquid. The condensed liquid flows out of the coil's sloping tubes to the high pressure liquid receiver for return to the system.

The hot, saturated air is driven through the drift eliminators, where any entrained water droplets are removed. The condenser's fan then discharges this air stream out of the top of the unit at a high velocity, where it can dissipate harmlessly in to the atmosphere. The water which was not evaporated falls into the sump and is recirculated by the spray pump to the water distribution system above the condensing coil section.

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.

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

Individual Fan Drive System

The new PMCQ fan drive system provides individual motor to fan configuration as standard equipment on all models. The dedicated fan to motor arrangement ensures less “wear & tear” on the drive system versus tandem fan motor drive arrangements resulting in less maintenance. The individual motor to fan design offers greater capacity control flexibility to match the system load requirements. In addition, all Evapco condensers are equipped with an internal baffle system which extends from the pan bottom vertically through the coil bundle. This unique design allows the user to cycle fan motors independently without harmful effects of air by-pass inside the unit. The individual motor to fan design ensures maximum operating redundancy in the condenser fan system when critical operation is necessary.

Single speed fan motor

Each Evapco PMCQ is equipped as per standard with heavy duty, single speed IP55 TEFC electrical motors.

Standard axial Super Low Sound Fan

The PMCQ cooling tower comes standard with Super Low Sound Fans. A one-piece molded heavy duty FRP construction utilizing a forward swept blade design. They reduce the overall sound generation compared to forced draft centrifugal towers, and additionally reduce the energy consumption by 50%.

4. Water distribution

ZM II ™ Zero-Maintenance spray nozzles

Even and constant water distribution is paramount for reliable, scale-free evaporative cooling. EVAPCO's Zero Maintenance ZM II™ Spray Nozzle, mounted in a PVC distribution pipe with end-caps remains clof-free under the toughest conditions to deliver approwimately 4 l/s tovery square meter of coil paln area. The heavy-duty nylon ZM II™ Spray Nozzles have a 33 mm diameter opening and a 38 mm splash plate clearance, enabling EVAPCO to use 75 % fewer nozzles.

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.

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.

5. Maintenance and inspection

Fan Drive Accessibility

The drive components of the PMCQ are easily accessed for routine maintenance from the front of the unit. Bearing grease fittings are extended to the outside of the unit for ease of lubrication. All drive sheaves have been relocated to the front of the fan section and motors are positioned on a platform base to allow for easy belt tension.

Oversized Access Door

For enhanced basin accessibility, the Oversized Access Door enables maintenance pesonnel to quickly and easily enter the basin for float valve adjustment and unit inspection, cleaning and maintenance.

Easy Clean Sloped Basin

The PMCQ drain pan is designed to improve maintenance access and make it easier for operating technicians to clean. The bottom of the pan is sloped to the unit drain to ensure that the basin will completely drain and allow sediment and debris that may collect in the basin to be easily flushed from the unit. The design helps to prevent buildup of sedimentary deposits, biological films and standing water.

6. Operational control

Mechanical water level control

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