Cooling Tower Installation

For the second question, many cooling tower manufacturers have an installation guide manual that gives recommendations for spacing between adjacent towers, walls, or other obstructions. This would also depend on the size(s) of the tower(s) involved, as well as the inlet geometry (such as inlet on one side versus more sides). One rule of thumb I have seen is 1.5 times the height of the inlet area.

If you have a congested area, you can add discharge hoods that send air upward at higher velocity, thereby decreasing air circulation back to the inlet. This typically requires a larger fan motor, however.

No water-based, evaporative cooling tower can achieve a lower cooling water temperature than the wet-bulb temperature of the air passing through it.

The performance of cooling towers is influenced more greatly by wet-bulb depression than any other factor. The next most important criterion is the operation of any fan to force the airflow through it.

The wind direction makes very little difference.

In an induced draft cooling tower some 20 to 30% of the heat dissipated is from conductive heat transfer and the rest from evaporative cooling. Wind direction will have very little effect on performance as the fan is the dominant draft provider, but may well need to be taken into account as far as drift or windage losses are concerned, especially in older design towers. Drift in a modern well designed tower is around 0.025% but in older towers it could be up around 0.5%, which is significant.

Tornado's rule of thumb for spacing sounds pretty reasonable.

1) I am assuming you are talking about a Large/Long multi-Cell Induced Draft (or Forced Draft) Process Plant Cooling tower.

There are the following important points to consider.

Prevailing wind:

• Direction, primary and secondary
• Timing, Spring, Summer, Fall, Winter
• Force
• Duration
  

Orient the cooling tower alignment so that it is parallel to the maximum wild direction.

This allows the wind to hit the narrow end of the tower structure and flow equally up both of the long sides where the air intakes are located.

If you orient the tower with the long "broad" side to the wind then you will "Starve" the down wind side, creating a slight vacuum effect which sucks water out the side of the tower. This reduces the performance of the tower.

2) As for clearance from any other object, just get as much as you can. A little extra cost for longer pipe runs will more than offset the cost of lost efficiency.

Here is a more extensive list of issues that need to be addressed when planning a Cooling Tower installation.

Cooling Tower & Cooling Water Supply Systems

Types

Once through system

Closed loop Cooling Tower system

Atmospheric (Flooded) System

Water Source

Municipal Water Supply (City, County, etc.)

River Intake

Ocean Intake

Lake

Wells

Surge Pond

Water Intake & Outfall Structures

River

Oceans & Bays

Tower Types

Forced Draft

Induced Draft

Natural Draft

Prevailing Wind

Direction (primary and secondary)

Timing (Spring, Summer, Fall, and Winter?)

Force

Duration

Basin Design

In-ground

On-ground

Underground

Strainers and Filters

Fixed Screens

Rotating Screens

Pump Types & Location

Vertical

Horizontal (same level next to basin)

Horizontal (elevated above basin)

Operations

Stand alone

Manned

Maintenance

Portable crane

Built-in lifting facilities

Cooling Water Supply and Return Piping

Material

Location (Above ground or below ground)

Water Treatment Chemical piping

PVC

FRP

Stainless Steel

Alloys

Cathodic Protection

Type

Pipe Riser Location

Insulating Flange Sets

Expanding on Tornado's comments and on PennPiper's #4 post-

While the manufacturers typically provide SOME guidance, you need to look at the installation. Assuming that you follow PennPiper's guidance of locating the towers to catch the prevailing wind "broadside" (90 degrees from intakes)- which is right not only because of the mentioned "vacuum" effect but also because the discharge air will be drawn into the down-wind side, dramatically reducing capacity because it raises the wet-bulb temperature significantly.

Any way- if you have two of more towers installed side by side (and they can be installed within 5 feet (1.5 M) of each other that way) you need to calculate the velocity of the air down each intake "chute". The air velocity between the towers and any barrier should be less than about 500 FPM (2.5 M/Sec) to avoid creating a vacuum effect on upstream towers and to allow easy air direction change. That means, for (3) 500 ton (1750 kW) towers at about 130,000 SCFM (3900 CuM/Min) per tower (65,000 SCFM per side means about 200,000 SCFM (6000 CuM/Min) at the first tower inlet. Assuming a tower height of about 15 feet (5 M) 500 FPM (2.5 M/Sec) means an area that is about 400 SqFt (40 SqM) or 27 ft (8 M) wide. Obviously, wider would be better.

Using the 500-ton towers again, the upward velocity is about1500 FPM (7.6 M/Sec) so even a 20 MPH breeze (1800 FPM or about 8 M/Sec) would only redirect the discharge about 50 degrees from vertical. so there should be no problem with downwind inlet contamination.

BUT- that same 20 MPH wind is obviously much faster than the desired 500 FPM across the inlets, so- ideally- you would install a deflector ramp/wall (or tower inlet blades) upstream of the towers to re-direct some of the breeze from the tower inlet air "chute".

Once again not enough information,is this a non mechanical cooling tower or powered? If it is powered wind direction shouldn't matter, if this is a bought in unit I assume that certain criteria was met & therefor should be right for the purpose it was made for,If however this is a built on site unit & non powered it would work on the basis that heat rises drawing cold air in at the bottom through the water as it falls, this type of tower has to have a waist to funnel the air and speed it up and increasing it's cooling capacity, these type need clear access around the bottom but as long as it is not surrounded by tall structures it would probably work ok if it had access on just one side,the thing to avoid is recirculating the air from the top.

Bazzer