Treatment-system.....is it useful for Cooling system?

Introduction for Treatment-system

It is important to realize that optimizing the ecology and operational efficiency of your evaporative cooling system is best accomplished by combining a chemical treatment regimen with some type of filtration.

The reason is that Treatment-system specifically targets suspended solids and particulates of 40 microns and below, while filtration systems are designed to stop larger debris, especially the kind that causes system clogging and fouling.

Poor water treatment lets water interact with the surfaces of pipes and vessels which contain it.

Cooling towers can scale up and corrode, but left untreated, the warm, dirty water they can contain will encourage bacteria to grow, and Legionnaires' Disease can be the fatal consequence.

The condenser tubes within a chiller and other water cooling equipment can also scale up and corrode thus preventing good heat transfer.

For example: Elimination of 1/32 inch of scale saved $15,018 per year.

Increased energy consumption and poor cooling performance is common result in inefficient water Treatment-system.

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.

Water Treatment-system for several industries is classified into three. Each of these treatment facilities has its own set of applications.

The categories are:

• Boiler
• Cooling water
• Wastewater treatment

• 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
• Locate cooling towers far from fresh air intakes and windows that can be opened.
• Consider prevailing wind direction and don't locate upwind or upstream of outdoor public areas.
• Don't locate in areas that can contribute debris and organic material.
• Consider the direction of prevailing winds and don't locate upstreamof any outdoor public areas.
• Consider future construction, including that on nearby sites.

• Keep system clean using a microbial treatment program.
• Use a qualified water treatment consultant to establish and oversee a water treatment program.
• Keep system free of debris that can contribute to the food source for legionella. (Air Intake Filters can help to control debris and organic material build-up).
• Inspect and clean cooling equipment if it is found to have a build-up of dirt, organic matter or other debris.
• Inspect drift eliminators and clean or replace as needed.
• Keep maintenance and operational records that include equipment manufacturers maintenance manuals, description and dates of the water treatment-system, inspection dates, MSDS documentation on all treatment chemicals, equipment repair records including dates, system water volume records, and the names and phone numbers of individuals responsible for system start-up, maintenance and shut-down.

A well designed and implemented water treatment program is highly important to the operation of any steam boiler, centrifugal chiller and cooling tower.

How to select the treatment

Most water treatment programs include water softeners, inhibitors and other chemicals needed to 'treat' the water in order to reach the desired conditions for mechanical use and heat transfer.

Products used to maintain proper water conditions are often fed automatically by sophisticated equipment directly into a chiller or boiler's water.

Water is used for both cooling and heating in large commercial building applications. In most industrial environments water is used for cooling production equipment or an ingredient to making a product.

How the water is used will determine what type of treatment is necessary.

Effectiveness of Ozone on treatment

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.

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

Example for Ozone applications

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 and shown to be effective.

References:

Center for Disease Control - December, 2000 Article, MMWR - July 1994, National Institute of Environmental Health, American Society of Heating, Refrigerating and Air Conditioning (ASHRAE)


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