Rental/Lease Units

WSAC Units are the currently in place at some of the largest refineries in the United States.

Other WSAC Applications Include:

- Vacuum Steam Condensing

- Auxiliary Cooling

- Natural Gas Condensing

- Wastewater Cooling

- Propylene Condensing

WSAC RFQ Datasheet

Contact a WSAC Engineer

How the WSAC works:

Niagara’s evaporative heat exchangers, after coolers and vapor condensers are more generally termed “Wet Surface Air Coolers” (WSAC).

In a WSAC, warm process fluids or vapors are cooled in a closed-loop tube bundle i.e. the process fluid being cooled never comes in contact with the outside air. Open loop water is sprayed and air is induced over the tube bundle resulting in the cooling effect. Some examples of cooling applications are:

The Basics:

1. Air is induced downward over the tube bundles.

2. Water is sprayed over the tube bundles concurrent with the airflow. The spray water continually drenches tube surfaces.

3. Heat from the process stream inside the tube bundle is released to the cascading water. The water, in turn releases the heat into the air.

4. The air stream is forced to turn 180° before exhausting upwards and out the fan stacks. This provides maximum removal of free water before the air is exhausted.

5. Fans discharge air vertically at a velocity sufficient to prevent recirculation of the saturated air.

The wet bulb temperature is the lowest temperature that can be obtained by evaporating water into the air. The wet bulb is determined by a combination of relative humidity and ambient air temperature. For example if the relative humidity is 60%, and the ambient air temperature is 70^oF, the corresponding wet bulb temperature is 61^oF. Over the past 100 years, Niagara has mastered the art of designing each cooler specifically to the needs of each application.

 Liquid Cooling
• Up to max inlet temp of 180°F

Single phase gas cooling
• Up to max inlet temp of 450°F

Turbine exhaust vacuum steam condensing
• As low as 1.8” HgA min
 

The WSAC operates with induced draft co-current flow, which means that the air and spray water are both traveling in a downward direction across the tube bundle. This configuration ensures that spray water is evenly distributed over the entire tube surface and essentially minimizes the risk for fouling. 

Other cooling methods use a counter-current flow, (air traveling up and spray water traveling down). This creates turbulence on the bottom of the tube. This turbulence results in incomplete distribution of the spray water over the tubes, which leads directly to fouling of the tube surface and a drop off in thermal performance.

As the cascading spray water mixes with the air, an equilibrium temperature forms as the water evaporates to the air, thus the warmed air and water mix together in the plenum/basin area providing inherent freeze protection during operation. Heaters can be included for non-operational cycles.

Skidded Prepackaged Unit, GE LM6000 Auxiliary Water Cooler

Field Erected Unit, Concrete WSAC Using 6 Niagara Tube Bundles

Variations

Niagara offers two variations of WSAC’s. All metal work is fabricated at the factory in Buffalo, NY. 

Prepackaged Niagara units, like the one pictured above, is designed as a single skid with no field assembly required. These units can be shipped directly to the job site for easy and immediate installation.

Field erected units like the one pictured above are the largest design type Niagara offers. Constructed using either concrete or FRP (Fiberglass Reinforced Plastic), field erected Niagara units offer the ability to cool high volumes of process fluid in a smaller plot area (footprint) than a traditional cooling tower. Observation and maintenance of the spray water distribution system can be accomplished without structure entry, fan shut down, or pump shutdown, providing 24 hour operation. Access doors and hatches also allow for cleaning and inspection of the lower water basin.

Uniform Spray Pattern

Custom Designed

Niagara engineers have been providing cooling solutions for over 100 years for a wide variety of clientele. Each WSAC is custom designed to fit a particular application. Design parameters are based on customer specifications for input and output temperatures as well as average weather conditions. All WSAC units are tailored to meet the unique needs of the most demanding applications in the world.