Can Water Treatment Save Energy?

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May 8, 2008

1. Exactly what is water treatment and is it necessary?

Water treatment describes a process used to make water more acceptable for a desired end-use. These can include use as drinking water, industrial processes, medical and many other uses. The goal of all water treatment process is to remove existing components in the water, improving it for subsequent utilization.

In the mechanical industry water treatment is a method used to optimize most water-based mechanical and industrial processes, such as: heating, cooling, processing, cleaning, and rinsing, so that operating costs and risks are reduced.

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.

Most water treatment companies use test kits and chemical dispensing systems which have made the use of water treatment chemicals in chiller, boiler and cooling-tower systems much easier. But attention to details, such as how often systems are tested, is critical to system performance. The correct water treatment chemistry at the correct time is extraordinarily important because even minor problems can create major costs.

2. How does poor or no service effect mechanical equipment?

Improper Water Treatment or no treatment at all will increase your energy consumption and operating cost while decreasing your mechanical equipment's efficiencies and life expectancy. A well designed and implemented water treatment program is highly important to the operation of any steam boiler, centrifugal chiller and cooling tower. All three of the systems shown below utilize water for cooling and heating.

Poor water treatment lets water interact with the surfaces of pipes and vessels which contain it. Steam boilers can scale up or corrode, and these deposits will mean more fuel is needed to heat the same amount of water. 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. Increased energy consumption and poor cooling performance is common result in inefficient water treatment.

Water treatment can often be categorized as 'low-tech' and unglamorous. However, the right chemicals, proper chemical feed equipment, and a dedicated service provider is essential to your mechanical equipment and should be 'treated' with top priority.

3. Are there energy savings with water treatment?

Treatment Value: Expert water treatment can cut your water, energy, and maintenance costs substantially. Perhaps most important of all, it can save you the cost of fixing or replacing equipment that’s been damaged by inadequate water treatment – including the downtime and lost revenue usually associated with solving such problems.

The examples of water treatment ROI (Return of Investment) shown below show how very thin layers of deposited material from poorly treated water can drive up energy costs.

Scale

System: 1,000 ton chiller

Operation: 12 hours/day, 365 days/year

Cost of electricity: $0.10/kWh

Scale thickness: 1/32 inch

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

Biological Fouling

System: 1,000 ton chiller

Operation: 12 hours/day, 365 days/year

Cost of electricity: $0.10/kWh

Bio-film thickness: 1/1000 inch

Elimination of 1/1000 inch of bio-film saved $26,834 per year.

"As little as 3/16-inch of scale can cause a boiler system to use 38 percent more fuel. The most miniscule amount of dissolved oxygen in the water also means a system could be headed for corrosion problems. And even a thin layer of bacterial slime in chiller tubes can significantly affect heat-transfer efficiency."

To find out more about your business or industry can save money on energy costs through water treatment, contact the experts at PWA Engineering at 757-366-5325

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