Evaporative Condensers

eco-ATC-A Evaporative Condenser

eco-ATC-A Evaporative Condenser

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

The new eco-ATC-A (Advanced Technology) design dramatically increases the efficiency in both the evaporative and dry cooling modes of operation thereby saving water and energy.

The eco-ATC-A utilises EVAPCO's new patent pending Ellipti-fin coils which are the Most Efficient Evaporative Condenser Coil in the refrigeration industry! The Ellipti-fin features elliptical spiral fin technology to maximize the surface area available for heat transfer. The elliptical tube design allows for closer tube spacing, resulting in greater surface area per plan area than round-tube coil designs. In addition, the revolutionary Ellipti-fin design utilises spiral fin technology and has lower resistance to airflow than typical finned coil designs. 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 eco-ATC-A condenser range is complient with the International Building Code (IBC). Evapco provides with each evaporative condensor a Thermal Performance Guarantee. eco-ATC-A units are constructed for a maximum nominal capacity 17.6 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 sumpv or a complete stainless steel construction (AISI 304 or 316 are possible).

Technical Data

  • Unit: Evaporative Condenser
  • Models: 455 Models (eco-ATC-A 179 till eco-ATC-A 4086)
  • Width: 2.283 / 2.388 / 2.991 / 3.607 / 4.906 / 7.344 mm
  • Design: Induced draft
  • Capacity: 900 till 17.600 kW
  • Air Flow: 11,8 till 199,3 m³/s
  • Fan: Axial
  • Drive: Powerband-belt driven

Properties

  • Reduced water consumption
  • High dry bulb switchover
  • Lower energy costs
  • Smaller plan area

Evaporative Mode

The refrigerant gas is discharged from the compressor into the inlet connection of the eco-ATC-A condenser. Water from the condenser’s sump is circulated over the condenser coil, while ambient air is simultaneously drawn into 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 to the high pressure liquid receiver for return to the system. The hot, saturated air is drawn 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 into 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.

Dry Mode

The refrigerant gas is discharged from the compressor into the inlet connection of the eco-ATC-A condenser. Ambient air is drawn into the unit and moves over the heat transfer coil. The air is warmed while the tubes containing the refrigerant gas are cooled. 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 to the high pressure liquid receiver for return to the system. The hot discharge air is drawn through the drift eliminators and then the fan then discharges the air stream out of the top of the unit where it can dissipate harmlessly into the atmosphere.

Low Fan Motor kW

The eco-ATC-A features the new EVAPCO Ellipti–fin™ coil, which utilizes elliptical spiral fin coil technology. This technology allows for up to 15% increase in thermal performance while offering model selections with reduced fan motor horsepower. This will results in significant energy savings throughout the year.

Reduced Plan Area

Due to the increased thermal performance, new eco-ATC-A also minimizes the footprint required for a given capacity thereby reducing the space required for an evaporative condenser. A smaller footprint means less steel and lower installation costs.

Significant Water Savings

The Ellipti–fin™ coil technology enables the eco-ATC-A to be operated in a 100% Dry Mode at a significantly higher switchover temperature than that of a typical bare tube coil evaporative condenser. This leads to a significant increase in the number of hours per year the condenser can operate in dry mode (spray pumps off), thus increasing your water savings.
This combination of features allows the eco-ATC-A to be operated with both energy and water efficiency in mind, making it the ideal choice for many installations.

Consider a meat processing plant application near Köln (Germany), where the unit is required to reject a constant heat load of 3000 kW of refrigeration at a 35°C condensing temperature and a summer design wet bulb temperature of 21°C. The process operates 24 hours a day 7 days a week. The eco-ATC-A evaporative condenser and an ATC-E evaporative condenser are compared as follows:

In the previous example, the eco-ATC-A model requires lower fan motor horsepower and smaller plan area than the equivalent ATC-E. The potential for reduced kW during wet operation is only one of the eco-ATC-A benefits.
The enhanced performance of the eco-ATC-A can be illustrated by the following diagrams.

Assuming a load profile requiring full 70% heat rejection requirement for a full time operation of the refrigeration system yields the following comparison between the eco-ATC-A and the ATC.

In the following diagram it is possible to appreciate the lower water consuption of eco-ATC-A compared to ATC: during the cold season the water consuptionof eco-ATC-A is no present or extremely low.

In the next diagram, it is possible to see that the energy consuption is lower during all the year thanks to the high thermal performance of the EVAPCO Ellipti–fin™ coil.

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.

Water Sight Tight air inlet louver (WST)

The air inlet louvers are both water and sight tight to ensure that the water stays in and sunlight stays out of the cold water basin. The water tight design maximizes thermal performance while minimizing water loss. The sight tight design also inhibits algae growth more effectively than previous designs.

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

Ellipti-fin evaporative coil

The new eco-ATC-A Closed Circuit Cooler utilizes Evapco's patent pending Ellipti-fin coil design which assures even greater operating efficiency. The elliptical tube design allows for closer tube spacing, resulting in greater surface area per plan area than round-tube coil designs. In addition, the revolutionary Ellipti-fin design utilizes elliptical spiral fin coil technology and has lower resistance to airflow than typical finned coil designs. This permits greater water loading, making the new Ellipti-fin coil the most effective design available. The coils are manufactured from high quality steel tubing following the most stringent quality control procedures. Each circuit is inspected to ensure the material quality and then tested before being assembled into a coil and encased in a steel framework. Finally, the assembled coil is pneumatically tested in accordance with the "Pressure Equipment Directive" - PED 97/23 EC. After fabrication, to protect the coil against corrosion, the entire assembly is hot-dip galvanized.

3. Mechanical design

Power-Band Drive System

The eco-ATC-A Closed Circuit Cooler features the highly successful, easy maintenance, heavy duty Power Band Drive System. It consists of Standard heavy-duty pillow block bearings with a minimum L10 life of 75,000 hours, extended lube lines, external motor/belt adjustment, aluminum alloy sheaves, solid-back multi-groove Power- Band belts and totally enclosed motors.

Single speed fan motor

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

Standard axial fan

The standard fans are heavy duty statically balanced axial propeller type. The fans are constructed of extruded aluminum alloy blades, installed in a closely fitted cowl with venturi air inlet for maximum fan efficiency. Each fan blade is individually adjustable. The fan cowl is covered with a heavy gauge hot dip galvanized wire fan guard.

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

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.

5. Maintenance and inspection

Large access door

A large hinged access door is located on the side of the unit for easy access to the fan drive system. The belt can be adjusted by tightening the tensioning-bolts on the motor base and the tension can be checked easily through the access door, all while standing at the side of the unit. The bearings can also be lubricated from the side of the unit. The bearing lubrication lines have been extended to the exterior casing and are located by the access door.

6. Operational control

Mechanical water level control

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