Effective Cooling Tower Water Treatment

Here in the Phoenix metropolitan area, adverse water conditions require intelligent water treatment strategies to adequately maintain water cooled equipment. Proper management of the characteristics of the cooling tower sump water along with maintaining good tower hygiene in general accomplishes at least four positive things.

1) It avoids wasting excess water.

2) It inhibits scale formation.

3) It controls biological growth.

4) It reduces the corrosion rate of metal parts in the tower.

Let's discuss how a cooling tower operates to understand why proper water treatment is important.

Most residents in the valley are familiar with an evaporative cooler. Water from the evaporative cooler sump is circulated by a pump over pads in the evaporative cooler and outside air is drawn through the pads. As the air is drawn through the wet pads some of the water evaporates and cools the air. The cooler air is then circulated into the space where cooling is desired. In the process of cooling the air, the water being recirculated across the pads is also cooled.

That is exactly the same principle being employed in the cooling tower, but on a much grander scale. Rejecting large quantities of heat from a building's mechanical system requires a lot of water to be evaporated. For example, a one hundred ton water cooled chiller operating at full capacity for 24 hours would require the evaporation of more than four thousand gallons of water. That brings us to the subject of the characteristics of the make up water. Make up water is the water supply that replaces the water being evaporated in the cooling tower.

Here in the metro area, water conditions vary widely because our water comes from several different wells as well as surface sources. The water quality may change rapidly over a short period of time because different sources are utilized for the water supply. Each well has different water characteristics and they often vary widely from one side of town to the other. Water that comes from surface sources, like the Central Arizona Project will usually have significantly different characteristics than well water. Surface water quality may also be influenced by weather conditions such as drought or increased runoff.

As water evaporates in the cooling tower all of the non-volatile components stay behind in the sump of the cooling tower. There is actually a lot more in water than what we would call hardness (carbonates). There are also chlorides, suspended dust particles and biological microorganisms. As more and more water is added to replenish the water that is being evaporated, these dissolved and suspended components in the sump water continue to accumulate. If no measures are taken to control the concentration of these components in the water, the solution eventually increases in concentration to a point where "stuff" starts coming out of solution. This "stuff" ends up getting deposited on the surfaces that the water comes in contact with.

Have you ever seen an evaporative cooler where the pads haven't been changed for a long while? I've seen them so encrusted with mineral deposits that the blower could no longer pull air through them. I've also seen them produce a bounty of biological growth in the sump water. That is exactly what will happen in a cooling tower without adequate attention to hygiene and an appropriate water treatment strategy.

When solids that are dissolved in water come out of solution they are deposited first on heat exchange surfaces and surfaces where the water is being evaporated. Heat exchangers, water cooled condensers, drift eliminators, the tube bundle in closed circuit cooling towers and the fill in open cooling towers are a few examples of surfaces where this occurs.

Deposition of mineral scale, dirt and biological fouling on any heat exchange surfaces can result in reduced heat transfer, reduced tower efficiency and increased energy costs. While reducing deposition of these is important with regard to the cooling tower, it is absolutely critical to avoid scaling or fouling in the water cooled condenser. Scaling and fouling in the condenser significantly reduces heat transfer capability and will seriously impact energy costs, performance and reliability.

A two part strategy is usually employed to manage the mineral content of the sump water. Part one is to maintain the sump water pH within allowable limits and to feed the correct type and amount of chemicals to help the water keep more of the dissolved solids in solution. Part two is intentionally sending some of the sump water down the drain (blow down). Blow down reduces the highly concentrated mineral content of the sump water by diluting it with the fresh make up water being added to replace the intentionally wasted water.

Biological growth can also become a significant health risk depending on the particular organism involved. Allowing mud and biological growth to accumulate in the sump of a cooling tower can accelerate corrosion of the sump and shorten the life cycle of the cooling tower. It can also provide a haven for microbes to escape the effects of a biocide.

Proper water treatment strategy and good cooling tower hygiene is not a one size fits all solution. The quality of the make up water will require an adjustment of the type of the chemicals and biocide utilized. It may also require changing feed and blow down rates for proper control. In addition, these requirements may be altered by the characteristics of each individual cooling tower installation.

According to Alan Bateman of DB Water Technologies, there are several things a good cooling tower water treatment program should address in order to be effective. They are total dissolved solids (TDS), hardness, pH, chlorides, suspended solids, an appropriate method for biological control and a proper blow down strategy. Each cooling tower manufacturer publishes recommendations for maintaining proper water conditions of the sump water. The advice of a qualified water treatment professional is advised to ensure that each item above is included in your overall strategy for cooling tower water treatment.

Mark Strahan is a 35 year veteran of the HVAC industry and is currently an account manager with Burt-Burnett, Inc., an HVAC mechanical service and EMS controls contractor. Mark can be reached with comments or questions at (480) 557-8593 or strahan@burt-burnett.com

Cottonwood Air Intake Filter Screens

When you think of chiller and cooling tower maintenance the first thought is usually about how much of a hassle it is to perform this important but unpleasant task; power washers, cleaning solvents hoses, buckets and other cleaning accessories need to be assembled and moved from unit to unit, up and down off of rooftops, behind buildings and other out of the way locations; chillers and cooling towers need to be opened, housings need to be removed and internal components power washed (all the while getting the debris from the cleaning process all over you) then the equipment needs to be reassembled before moving to the next one - WOW, what a hassle!

As unpleasant this job is, ensuring that the cooling equipment which supports your production process stays clean and running efficiently is one of the most mission critical jobs there is because if your process cooling equipment fails due to system fouling, then production will fail - costing the business thousands of dollars in maintenance, repairs, downtime and lost productivity.

In most regions of North America, cottonwood seed is a major contributor of cooling equipment fouling. This naturally occurring airborne contaminant (generated by the Poplar Tree) usually effects operations from May thru early August, hence, companies that rely upon process cooling must clean their equipment frequently during this period or risk failure. Then comes the dog days of summer when insects, paper, construction debris, birds and just about everything that blows in the wind seems to find its way into your cooling equipment, then comes the final seasonal assault during the fall season when the trees drop their leaves, scattering them to the wind where they always seem to find their way to your condenser coils and cooling towers.

Keeping up with HVAC maintenance during the spring, summer and fall is nearly a full time job for most production operations and as the economic realities of business cause maintenance budgets and staffing to be reduced, it is increasingly important that companies find effective maintenance solutions that will streamline their day to day HVAC maintenance activities and enable them to more effectively handle work loads with fewer people and with fewer budget dollars.

Think about it, if you are in a lean maintenance staffing situation and you had five things to do on any given day and one of the tasks was cleaning condenser coils and cooling towers, how high on the "To Do List" would it rank? Given that it's time consuming and hard, dirty work, most people would rank it pretty low; Unfortunately, if the equipment is in need of cleaning and maintenance continues to be delayed, no reason for delaying it will change that fact and the equipment will continue to operate at an increasing level of inefficiency until the equipment can no longer support the cooling requirements.

Now consider the same list of five things to do except this time cleaning cooling towers and chiller coils only took a few minutes per unit using a broom, now where would this task would fall on the "To Do List"? Well, there's no real way of knowing, but the likelihood of it ranking high on the list is pretty good. Furthermore, if cleaning the equipment was as easy as using a broom or rinsing with a garden hose and it didn't require opening or disassembly of the equipment, then nearly anyone could perform the maintenance and that would change the dynamics of the HVAC / Cooling tower maintenance process.

How to Change the Dynamics of the Maintenance Process.
Air Intake Filtration specifically engineered for use on condenser coils, cooling towers and other HVAC equipment is one of the best ways to prevent fouling of your equipment. Unlike window screen, bug screen, shade screen and conventional filters including roll media, pleated filters and electrostatic filters which are largely designed for internal use on air handling units and forced air heating systems, Air intake filters are specifically designed to mount to the outside of the equipment where it stops airborne debris before it enters your system and where it can be easily seen and quickly removed using a broom, brush, shop vacuum or by simply rinsing with a garden hose - Even the rain has a cleansing effect on air intake filters and they never need to be removed for cleaning. Furthermore, because of the critical airflow requirements on cooling towers, and air cooled chillers, air intake filters are specifically engineered to be nearly invisible to the airflow on high volume / high velocity air flow systems (static pressure drop is less than 1/10" w.g. at 600 fpm air velocity).

So What's The Big Deal About Air Intake Filtration? Air Intake Filters help eliminate the "hassle factor" by dramatically reducing HVAC maintenance time and effort - but the benefits don't end there; here's what else they will do to save budget dollars and change the dynamics of your maintenance process:

Condenser Coil Filter Screens -Benefits

* Prevents debris from getting into coils.
* Reduces / eliminates annual pressure washing
* Reduces / eliminates need for cleaning chemicals
* Helps reduce energy cost because coils stay clean all season long.
* Dramatically reduces maintenance, repairs, downtime and lost productivity.

Cooling Tower Filter Screens - Benefits

* Reduces / eliminates sludge build-up in the basin by significantly reducing bio-loading.
* Prevents fouling of fill.
* Prevents plugging of strainers, blow-down valves and heat exchangers.
* Helps reduce algae growth by diffusing sunlight, which supports photosynthesis.
* Reduces water treatment chemical consumption due to reduced bio-loading.
* Dramatically reduces maintenance and repair cost, downtime and lost productivity.

Air Solution Company developed and patented the first Air Intake Filter specifically engineered to mount to the outside of cooling towers and other HVAC equipment for purposes of stopping the debris before it entered into the system. Since that time, Air Solution Company has been manufacturing and has introduced a variety of other innovative filter systems including its new Fine Mesh Filter which is engineered for use on small and medium size refrigeration coils and machine fan intake housing units. Air Solution Company Randy Simmons is with Air Solution Company, author of articles can be reached at http://www.airsolutioncompany.com

Cooling Tower Products "Fill Removal"

Cleaning and maintenance of a cooling tower is a tedious process but it is very much necessary and imperative. I have handled and managed few of the cooling tower cleaning and maintenance in my previous plant. It's challenging enough. You need to have the skills and must be very careful. The cooling tower is huge, high and deep. Safety precautions cannot be compromise.

The following video shows how cooling tower fill is being removed. This will provide you some idea if you have not done this before. This video is provided by 1500 series Cooling Tower. coolingtowerproducts.com Ph: 800-733-1584

What Are Cooling Towers?

What exactly are cooling towers anyway? They are heat rejection devices used to extract waste heat into the air from the cooling of a water stream to a lesser temperature. They are also referred to evaporate heat rejection devices. These devices provide lower water temperatures than an air cooled or heat rejection devices.

Cooling towers are used in air conditioning, electric power generation and in various manufacturing facilities. They can be referred to both open circuit and closed circuit heat rejection equipment.

Small cooling towers are designed to handle only a few gallons of water per minute, which is supplied by small pipes. The large towers cool hundreds of thousands of gallons of water per minute. The pipes supplying the water are up to fifteen feet in diameter. These are found in large power plants.

There are several different types of cooling towers. One such type is the mechanical-draft cooling towers. They rely on power driven fans that draw or force the air through the specific tower.

Another type of cooling tower is the natural draft-cooling tower. It uses buoyancy of exhaust air rising in a chimney to provide the needed draft for cooling. Another type is the fan-assisted natural draft tower uses a mechanical draft to expand the buoyancy.

In the past, they relied on the prevailing winds to get the air drafts needed for cooling.

Cooling towers can emit a lot of noise. Things that cause the noise include the sound of water falling, the sound of large fans along with motors and drive belts as well.

Many terms are associated with water coolers. We will briefly go over a few of them. Leaching refers a loss of wood preservative chemicals caused by the washing action of flowing water through a wooden cooling tower. A plume is a stream of exhaust leaving the tower.

Blowouts are water droplets that are blown out of the cooling towers with the exhaust air that is blown out.

There is more to learn about cooling towers, so please visit our website today

Your guide to everything you have ever wanted to know about a cooling towers and heat exchangers. We also provide information on various types and brands of heat exchangers. Visit our site today!

http://www.theheatexchangers.com

By D. Karlson

Ozone Helps Business and Industry Be "Cool"

Many commercial and industrial processes depend on cooling towers to maintain temperature in a designated range. The one most people are familiar with is building cooling (HVAC systems), but many important industrial processes also require cooling towers such as electrical power generation.

Cooling towers use the principle of evaporative cooling to reduce the temperature of water. The human body uses the same principle. As we heat up we sweat, as this water evaporates from the surface of our skin we cool down. In a building the air conditioning system uses cooling heat transfer fluid to carry heat from inside the building to the outside. This fluid in turn needs to be cooled so it can return to the building and pick up more heat. Water is used for this purpose. The cooling water is then taken to a cooling tower where it is allowed to evaporate cooling the water so it in turn can lower the temperature of the heat transfer fluid used inside the building.

Since the cooling water is constantly evaporated more water must be added to the tower (make-up water) to maintain the volume. In addition, because the minerals in the water concentrate with evaporation, some water has to be released to reduce the concentration of the minerals (blow down). Since the cooling tower water is warms, oxygenated and constantly exposed to the environment, it is a good medium for the growth of bacteria. Some of these bacteria can be harmful such as the Legionella bacteria that can cause illness in humans. Other bacteria can form surface films (biofilms) on the heat exchange equipment that reduce the efficiency of the cooling system and thus waste energy. Some of the organism can also cause the materials in the cooling system to corrode requiring replacement of expensive equipment. As a result the growth of micro organisms in the cooling water must be controlled.

Ozone generators have been used extensively for the treatment of cooling water. This is due to the fact that ozone is a powerful, but environmentally friendly biocide. Ozone's effectiveness has been studied by the various agencies of US government and shown to be effective. For example, NASA uses ozone to treat cooling water at the Kennedy Space Center where they conduct racket launches.

Ozone is a powerful biocide, which, when compared to conventional chlorine based biocides, not only combats microbial growth processes but also reduces organic impurities often found in the cooling water reducing potential discharge problems with the blow down. In addition, by reducing the concentration of these impurities the amount of water blown down or wasted can also be reduced.

Ozone is produced in an ozone generator and usually injected continuously into the cooling water system in a branch stream. The microorganisms in the systems are thus under permanent attack and micro organism counts are held at a very low level. This also applies to the bio films in the systems, so the tendency for coatings to form is kept to a minimum. This means that intervals between overhauls and maintenance sessions can be extended.

A residual ozone concentration of 0.1 to 0.2 ppm is typically effective in keeping the cooling tower and the cooling circuit clean.

Advantages of ozone generator use in cooling towers include:

• Lower Corrosion Rates
• No Toxic Chemicals in Blow Down (ozone breaks down to oxygen).
• Lower Overall Chemical Use
• Eliminates Storage of Biocides (ozone is produced on site from air)
• Effective in a Wide pH Range
• Improved Heat Transfer Efficiency
• Reduced Water use

Ozone use in cooling towers requires consideration of the following factors:

• Make-up Water Quality (Hardness, COD Levels)
• Dead Spots in the Circulation System
• Water Temperature
• Materials of Construction

When applied properly and in the proper circumstances ozone can improve the operation of cooling towers while saving money and protecting the environment.

Anthony Sacco is a director of Spartan Environmental Technologies, LLC. Spartan supplies ozone generators, ozone water treatment systems and other advanced oxidation processes. You can learn more about Spartan at http://www.spartanwatertreatment.com and ozone cooling water treatment at http://www.spartanwatertreatment.com/cooling-water-treatment.html

Water Treatment by Using Ozone

No water is ever pure. It is a little bit of a fairy tale when you think that water can be. Water is a universal solvent. When water is given to the environment, it becomes immediately contaminated with many different organic and inorganic substances.

Not every one of the contaminants is bad for you. Some of them can be toxic for humans to consume. The water treatment systems are designed and necessary for removing these substances from your water and giving you clean and safe water to drink.

There are many different water treatment systems to choose from. It will depend on the water that you are trying to get treated. One of the water treatment methods that you may want to try is known as the ozone water treatment method.

What is meant by ozone?

Ozone or O3 is a gas that has no color or smell to it. The ozone gas will have a reaction with anything that it comes in contact with. Because of this reaction, the ozone is used largely for cleaning and disinfecting things. The ozone gas is so highly reactive that it will cause corrosion on the things that it meets. Ozone is a great way to disinfect and clean but, for living tissue contact, it can be damaging in great ways.

Why Use Ozone Gas To Treat Water?

It is a very easy answer; ozone is the greatest biocide that is available. It reacts in a big way with the water and this makes it a great thing for water treatment. Ozone gas will kill viruses, bacteria, microorganisms, and fungus in the water. It can also stop scale deposits from forming and causing hard water to occur.

In certain research studies, legionella has also been destroyed by ozone gas. Legionella is a bacterium that is found to thrive in cooling towers. Every test that has been done shows that by sending ozone gas into the cooling tower will lower the bacteria counts and will provide standards for drinking water that is of a better quality. Ozone gas has also been shown to impact corrosion in the heat surfaces in a positive way.

Good Things For Ozone Water Treatment Use

The main good quality of using an ozone water treatment system is that it is able to get rid of the microorganisms that are found in water. Biological films ore one of the worst problems facing today’s supply of fresh water. By getting the biological agents under some sort of control, the ozone water treatment system can make sure that the water is free form viruses, bacteria, and other substances.

The ozone water treatment system will also help to eliminate the problem of scale deposits in the pipes. Because it inhibits the gathering of scale deposits, it will help to improve the work quality of the heat transfer surfaces. This ozone gas will make the system very good for industrial use and especially good for those systems that use water to heat or cool.

You can also find more info on water treatment and extensive water treatment. eWaterTreatmentSystems.com is a comprehensive resource for water treatment with information on reviews, reverse osmosis and how it works.

Learn How to Prevent and Solving Scale and Scum in Cooling System

Having headache with your cooling tower scum and scaling problems. Check out this simple technique to avoid all those problems using an environtally friendly and biodegradable chemical. Micro-nice® D-5 is the product for preventing and solving scale and scum in cooling tower. Without using any petrochemical-solvents, but made from Phytochamical mixtures instead.





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