Reducing water use in cooling towers and evaporative. A oncethrough cooling system pumps water into equipment where it passes over a hot surface in order to cool it. Cooling towers are treated by chemicals and other water conditioning processes to prevent these problems. Cooling towers are commonly of the induceddraft, crossflow variety, although counterflow and forceddraft cooling towers are also represented.
Simple and effective in a wide range of applications, this. Engineering report and the project design documents. Cooling tower water treatment rochester midland corporation. When an industrial facility might require a cooling tower water treatment system, it is a decision that shouldnt be taken lightly. This publication describes water treatment requirements for the most common systems, oncethrough and open recirculating. Cooling systems for comfort air conditioning and industrial processes usually have a cooling tower. Reducing water use in cooling towers and evaporative condensers. System design, including system capacity, cooling tower type, basin depth, materials of construction, flow rates, heat transfer rates, temperature drop and associated accessories 2.
Cooling water microbial control impacts overall plant performance. Unfortunately, there is no one size fits all water treatment program since the type and quality of the water supply that is available for makeup varies widely depending on geography, geology, and economics. All cooling towers functions to cool a circulating stream of water see figure version i. The purpose of the cooling tower is to remove heat from a circulating stream of water, sometimes referred to as condenser water. Cooling towers are used in power plants to reject heat to the atmosphere by lowering down the water temperatures that sustain the equipments reliability and plants production capacity. Suvpco technology for cooling tower water treatment has the potential to conserve water by. Mem07b maintain water treatment systems for cooling.
Water may also be used in ancillary feedwater treatment processes, such as softening. However, cooling towers and evaporative condensers require significant quantities of makeup water to compensate for losses associated with evaporation, drift or mist and blowdown or purge. Evaporative cooling system it comprises of two components. This article takes a look at some available water treatment methods to prevent the three primary problems associated with cooling tower water. A cooling tower water treatment system is an arrangement of technologies that remove damaging impurities from your cooling tower feed water, circulation water, andor blowdown. Sodium chlorite cooling water treatment with chlorine dioxide oxy. In a counterflow cooling tower, water sprays are used to distribute the warm water see figure 8. Pdf treatment of cooling tower blowdown water containing. There are cooling towers that create process water that can only be used once, before it is discharged.
Problems of cooling systems and possible solutions of suitable water treatment have been shown. From the sump cool water is pumped back to the heat exchanger. Preventive maintenance program and plan for cooling towers. The test result also hints to major failure of water treatment facilities andor operation requiring urgent rectification by the owners of the cooling towers. Treatment programs should include routine checks of cooling system chemistry accompanied by regular service reports that provide insight into the systems performance. Water treatment pwt systems used today to control scale formation in cooling towers. What is a cooling tower water treatment system and how does. For our purposes, we will cover three kinds of cooling towers based on how air and water flow counterflow.
The tower acts as a heat exchanger by driving ambient air through falling water, causing some of the water to evaporate evaporation gives off heat providing cooling and then circulates cooled water through whatever equipment needs for cooling. Water, including make up water composition quality, availability of pretreatment and assumed cycle of concentration 3. There are three basic types of cooling water systems. Conversion to recycled water has allowed biogen idec to realize significant cost savings through discounted rates and. In recent years, a variety of nontraditional water treatment technologies have been developed and presented to users of cooling towers as an alternate method of treatment. May 08, 2020 cooling towers with water samples found with total legionella count at or above the upper threshold of 1,000 cfuml shall undergo emergency decontamination.
A cooling tower is an installation that retreats heat from water by evaporation or conduction. As water evaporates, the concentration of dissolved solids increases rapidly and can reach unacceptable levels. Mem07b maintain water treatment systems for cooling towers. Claritys water treatment blog is dedicated to topics having to do with the water treatment industry. When the filter requires backflushing, the flow direction is reversed through each filter pod sequentially. Cooling towers should be located as near as possible to the refrigeration systems they serve, but should never be located below them so as to allow the condenser water to drain out of the system through the tower basin when the system is shut down. Development of innovative technologies for cooling, waste. To manage cooling tower water treatment gsa typically contracts with a company for a.
Biological control in cooling water systems using nonchemical treatment devices submitted to. Modern treatment substances and their properties in. All large towers, and many of the smaller towers, are prefabricated, piecemarket and shipped to the site for the cooling towers manufacturer usually provides final. The specific configuration of your system will depend on several things, including.
Mem07b maintain water treatment systems for cooling towers modification history not applicable unit descriptor unit descriptor this unit covers testing. More than 1,500 industrial facilities use large quantities of water to cool their plants 2. This article takes a look at some available water treatment methods to prevent the three primary. Watertreatment and chemical conditioning of open and closed. Water sampling of fresh water cooling towers statistics 646.
This system uses proprietary high efficiency softening technology to treat the makeup water to the cooling tower. Oct 05, 2016 when an industrial facility might require a cooling tower water treatment system, it is a decision that shouldnt be taken lightly. Our water treatment chemicals for cooling towers are developed for low, medium, and high hardness water. Cooling tower water treatment maintaining water quality cooling towers work by evaporating a small portion of water, approximately 1. Targets of cooling water treatment in open and closed circuits were pointed out. Typical closed loop cooling tower system is shown in figure 7.
For cooling tower systems, efficient heat removal is a requirement for both design and operation. As the universal solvent, water is capable of dissolving a variety of materials as well as holding. Jun 11, 2001 in recent years, a variety of nontraditional water treatment technologies have been developed and presented to users of cooling towers as an alternate method of treatment. Apr 08, 2014 for cooling tower systems, efficient heat removal is a requirement for both design and operation. Technical information for cooling towers using recycled water. Understand fully the implications of the control setpoints, feed limit and. As circulating cooling water evaporates, hardness and other mineral salts increase in concentration with resultant scale and corrosion effects. Also, refer to our technical bulletin, tower operation during the winter months. Cooling towers blowdown untreated towers fy 2011 cycle 1. Hidden costs reducing water consumption in cooling towers and.
Treatment method for cooling towers and heat exchangers. In fact, the primary maintenance task for cooling towers revolves around water treatment. When water is reused, it is pumped through the installation into the cooling tower. Dec 18, 2012 all cooling towers are designed to remove waste heat from water and transfer it to the atmosphere, but there are a lot of ways to accomplish this task. Cooling towers should also be cleaned at least 6monthly to remove fouling. In a crossflow cooling tower, the hot water basin is used to distribute the warm return water flow uniformly over the tower fill see figure 6. The cooling towers range in size from small to large capacity. Petrochemical plants, chemical manufacturers, refineries, and all kinds of large buildings and facilities using cooling towers, whether theyre used as part of the industrial process or for coolingremoving heat from the building. Cooling tower case study and was originally used to filter fine metal particles from hydraulic fluid on aircraft. Bibliography of technical papers cooling tower water. The use of basic filters 40 to 50 micron will help remove the solids from the water. There are current plans to increase all 3 vet med towers to 3.
We will outline these benefits later in the report. The fielderected cooling towers are those on which the primary construction activity takes place at the site of ultimate use. An introduction to cooling tower water treatment cedengineering. In order to make the addition of uv a reality, the cooling tower water treatment will also need to include a filtration system. University of pittsburgh department of civil and environmental engineering pittsburgh, pa 152612294 fullscale and pilotscale cooling towers. The wcti water conservation system is a patented, nonchemical water treatment system for cooling towers. Rp m 2 rp m 1 cfm 2 c fm 1 staticpressure 2 static pressure 1 cfm 2 cfm 12 ho rsep ower 2 ho rsepow er 1c fm cfm 3 formulas ra nge e ntering water tem per ature leavingwater temperature. Water treatment the purpose of a cooling tower is to remove the heat generated by an hvac system cooling of compressor refrigerant and heat generated by the compressor itself. At the extreme for water droplet loss is the spray pond that loses 0. Cooling water problems and solutions ced engineering.
Treatment of cooling tower blowdown water containing silica, calcium and magnesium by electrocoagulation. This means that water treatment must be completely effective to prevent. Watertreatment and chemical conditioning of open and. Bac discourages acid dosing as means of scale control except for open circuit cooling towers with remote sump. We cover popular water treatment topics that include boiler water, cooling water, and waste water treatment. Using soft water for cooling tower makeup is less common, however, notwithstanding that this strategy offers significant benefits over the use of hard water. Electrochemical water treatment for cooling towers nrel. Biological control in cooling water systems using non. The water then exits the equipment, taking heat with it. Cooling water systems remove heat generated from a variety of industrial processes. Proper water treatment is the lifeline of a cooling tower. As a result, there are also various types of cooling towers. Development of high cycle cooling water treatment program.
Cooling towers provide a costeffective and energy efficient operation of systems in need of cooling. The chemicals must be compatible with the unit materials of construction as well as other materials used in the system pipe, heat exchanger, etc. Water treatment cooling towers, evaporative condensers, ice. Treatment of cooling water will be different depending upon the kind of system in use. Cooling is accomplished through the latent heat of vaporization. There are also cooling towers that create water that can be reintoduced in the production process. All cooling towers are designed to remove waste heat from water and transfer it to the atmosphere, but there are a lot of ways to accomplish this task. Cooling tower water treatment recommendations brentwood.
Traditional approach is the use of water treatment chemicals to control scale, corrosion, fouling and microbiological proliferation ie legionella industry standard is to subcontract the ownership of the water treatment to an external specialist contractor. Microbial inhibition, as part of a robust cooling water treatment program, presents a special challenge because of the variability in makeup water sources, plant processes, and discharge permits. Water is a universal solvent and, as such, it is capable of dissolving and retaining high concentrations of minerals and deposits. The industries use cooling water in various processes. Environmental restrictions and the need for water conservation have led to the development of a new, high cycle cooling water treatment program. Internal chemical and external equipment based treatment possibilities and limitations have been discussed. Water, including make up water composition quality, availability of pre treatment and assumed cycle of concentration 3. Chemical treatment programs must meet the following requirements. Water based cooling involves water recirculating cooling towers and evaporative condensers. Cooling towers other uses of water healthy water cdc. Using highly treated recycled water for nonpotable purposes is an effective way to reduce the demand. Suezs combination of cooling tower treatment chemicals, software, monitoring and industry expertise can help prevent these issues or aid in the recovery from a failure event. The purpose is to define a preventive maintenance program and plan for cooling towers at the suny polytechnic quad c building utica new york.
The heat exchanger or chiller allows cooling water to transfer heat from production source without direct contact, creating heated water. What type of cooling tower you have open circulating, oncethrough, or closed loop. Oct 26, 2016 a cooling tower water treatment system is an arrangement of technologies that remove damaging impurities from your cooling tower feed water, circulation water, andor blowdown. Recirculating cooling water systems are found in most air conditioning chiller operations, as well as many heat exchange operations. The water from a cooling tower should be regularly sampled and tested for legionella bacteria to ensure the treatment regime being used is working effectively.
It is also an excellent medium for the transfer and removal of heat. What is a cooling tower water treatment system and how. Environmental nonchemical water treatment for cooling. Ask the water utility if it provides sewer credits for evaporative losses, which can be calculated as the difference between metered makeup water minus metered blowdown water. These pwt systems utilize pressuretemperature, magnetic flux, electric current, induced pulsed, static electric fields and catalysis. Industrial cooling water chemical programs maintain clean heat transfer surfaces. The main purpose of the cooling tower is to expel the heat from. Cooling towers are primarily used for heating, ventilation, and air conditioning hvac and industrial purposes. Water treatment for cooling towers 1 of 2 email a colleague. Sufficient information is included in this paper for a water treatment engineer to design, manufacture, and apply scale and corrosion control remedies throughout a wide range of conditions. Cooling towers are an integral component of many refrigeration systems, providing comfort or process cooling across a broad.
Opening the controller enclosure exposes user to the risk of electrical shock at power line voltages. Mem07b maintain water treatment systems for cooling towers date this. This will make the uv more effective and prevent solids from settling elsewhere in the cooling loop. Water treatment for cooling towers 1 of 2 water treatment helps ensure that heattransfer surfaces perform to design specifications by amanda meitz, senior microbiologist, nalco diversified technologies, inc. Calcium hardness is the primary cause of mineral scale deposits that form on heat transfer surfaces. Rp m 2 rp m 1 cfm 2 c fm 1 staticpressure 2 static pressure 1 cfm 2 cfm 12 ho rsep ower 2 ho rsepow er 1c fm cfm 3 formulas. Field data is presented for small to large cooling towers. Water treatment cooling towers, evaporative condensers. The fan deck supports the motor and fan of the water spray system. Standard chemical treatment of pilotscale cooling towers by the addition of free chlorine positive control was able to achieve appreciable reduction in both planktonic 23 orders of magnitude and sessile microbial growth 34 orders of magnitude in these towers. The fanlaws can be used topredi ctthe pe rformance ofa towerwitha nonstandard motor.
Ashrae 1719 tullie circle atlanta, ga 30329 submitted by. The cooling towers at biogen idec are the largest users of water in the facility. The water exits the cooling tower and is sent back to the exchangers or to other units for further cooling. Cooling towers can be categorized in a number of different ways, because there are so many differences between cooling towers. Corrosion, deposition, fouling, and biological growth can derail your operations. Cooling tower types cooling towers fall into two main categories. Regardless of the technological basis of these new treatment systems, the issues to be addressed will, and have, remained the same. Using soft water for cooling tower makeup nelsen corp. F o r m u l a s a n d t a b l es formulasandtables fanlaws.
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