The mass balance around a cooling tower as illustrated in the figure to the right is. They require specialized maintenance to ensure safe, efficient, and reliable operation, including an effective water treatment program. Control of the water level in the cooling tower basin is via a level instrument of some description. Water quality guidelines water treatment a proper water treatment program, administered under the supervision of a competent water treatment specialist, is an essential part of routine maintenance to ensure the safe operation and longevity of evaporative cooling equipment, as well as other system components. Calculation of effect of cycles of concentration on amount of.
In order to simplify and accelerate the analyses of oil and grease in industrial waters, particularly used in cooling water in heat exchangers, a uvfluorescent sensor sensitive to polycyclic aromatic hydrocarbons pah being part of refined oil products was tested. The thermal capability of a cooling tower used for air condition ing is often expressed in nominal cooling tower tons. Oilin water uv fluorescence sensor in cooling tower and other industrial applications. Cooling tower evaporation rule of thumb veolia water tech. Cooling tower makeup water flow calculation rea hvac. The circulating water flow is determined by the number of pumps running and the pressure drop in the overall circulating water system. Term that describes the mass flow relationship between the volume of makeup water and the volume of blowdown water. Using soft water for cooling tower makeup is less common, however, notwithstanding that this strategy offers significant benefits over the use of hard water. Cooling tower calculations water technology report. Cooling tower makeup water calculation with example. A correction is needed for factors such as wind, relative humidity, etc. At the same time higher cycle of concentration increases the dissolved solids concentration in circulating cooling water which results in scaling and fouling of process heat transfer equipments. The number 500 is a constant, therefore is independent of the cooling tower.
Cooling tower evaporative cooling system measurement and. All of the required cooling water was assumed to be makeup water, with the. We wanted to let you know how we use cookies on our site. When heat load is not at its maximum, air or water flow of the tower can be reduced and energy can be saved. Meanwhile, since the cooling water is a very effective air scrubber, dust and debris present in the upflowing air is washed out by downpouring water and collects in the sump. The term cycles of concentration compares the level.
Using soft water for cooling tower makeup nelsen corp. If the instrument is of the level displacer type, it should be housed in a still well located in the pump basin. In some large power plants, the cooling tower concentration cycles may be much higher. Evaporative cooling towers are usually designed to provide the proper cooling needed for the process when both production and the outdoor conditions are at their maximum. Please update the following information as it applies to your tower needs.
Water outputs from a cooling tower include controlled losses such as evaporation, bleed, drift and pump gland leakage and uncontrolled losses including leaks, splash out, overflows and windage. As evaporation continues, the water becomes more concentrated than the original make up water. This step will reduce the amount of ecolyme needed to descale the cooling tower. Makeup water usually is added to the cooling tower basin. Bibliography of technical papers cooling tower water. In addition to blow down, most recirculating cooling water system maintenance plans include controlled additions of. Evaporation loss is loss of water due to evaporation. Total seawater cooling towers makeup water requirement. Water treatment cooling towers, evaporative condensers, ice. C concentration of cooling water concentration in makeup water so that. Remember, trs can help with water saving designs and treatment systems. Cooling towers cool water by evaporating a small percentage of the recirculating water flow.
We use cookies to enhance your site experience and for functionality. Calculate the amount of makeup water required for a cooling tower with following conditions. Calcium hardness is the primary cause of mineral scale deposits that form on heat transfer surfaces. The amount of water evaporated from the cooling tower is a function of the recirculation rate and cooling range. Closed circuit systems differ in that the return fluid often water, or sometimes water mixed with glycol circulates through the tower structure in a coil, while cooling tower water recirculates only in the tower. Please consult the factory if you need more detailed information. The evaporation rate is approximately 3 gpm per 100 tons of refrigeration. Air flow is directly proportional to the thermal performance of your cooling tower. Water calculator spx cooling towers spx cooling technologies. The calculator is based on 50% relative humidity for ambient conditions.
Tap water as initial tower filling or makeup is the most used and is considered. The recirculation rate and the temperature drop across the cooling tower are the two pieces of data needed to calculate the amount of water lost from the open recirculating cooling system due to evaporation. To calculate the louvers size the following formula is used. For nearly a century, we have provided exceptional quality equipment and service to the hvac, process cooling, industrial, and refrigeration markets. If the makeup water is metered and recorded or there is some other way to determine the actual tower makeup such as water bills, adjust the so that the calculated makeup is the same as the actual makeup. Estimate evaporation loss and makeup water requirements. By continuing to use this site you consent to our use of cookies. Energy service company performance contractor hvac. This water is often discharged to the sanitary sewer system. Therefore, the cooling tower drift rate assuming 862,690 gpm circulating water rate would be. Cooling towers use the principle of evaporative cooling in order to cool water.
As with most cooling towers, chlorination would be required to prevent biological growth. Since the makeup water typically contains dissolved solids, these solids are typically left behind in the sump water as the water evaporates in the cooling tower. Blowdown from the cooling tower is treated in a reverse osmosis system operating at 90 to. Apr 18, 2001 softened and filtered water is then used as cooling tower makeup. In addition to blow down, most recirculating cooling water system maintenance plans include controlled additions of conditioning chemicals. While in the cooling tower, the water is naturally degassified to remove dissolved carbon dioxide. Softened and filtered water is then used as cooling tower makeup. Cooling tower blowdown equation by james mcdonald, pe, cwt originally published. Cooling towers work by evaporating a small portion of water, approximately 1. Oilinwater uv fluorescence sensor in cooling tower and other industrial applications. To calculate the makeup water flow rate, determine the evaporation rate using one of the following. Gallons per minute hot water temperature f cold water temperature f wet bulb temperature f. In summer the ambient air wet bulb temperature raises when compared to winter thus limiting the cooling tower efficiency. Mar 02, 2015 using soft water for cooling tower makeup is less common, however, notwithstanding that this strategy offers significant benefits over the use of hard water.
This should be located in the relatively still waters of the pump basin. If bleed is also metered, divide actual makeup by actual bleed to obtain obtain cycles of. A cooling tower is a specialized heat exchanger in which air and water are brought into direct contact with each other in order to reduce the waters temperature. Again, this will be a first issue releasing the actual engineering approach. Closed circuit systems differ in that the return fluid often water, or sometimes water mixed with glycol circulates through the tower structure in a coil, while cooling tower water recirculates only in. Almost 14 th of makeup water water added in a cycle to substitute water losses in a cooling tower is dissipated 25.
The evaporation rate is approximately 2 gpm per 1 million btuhr of heat rejection. Singlepass cooling uses a significant amount of water and can result in unnecessarily high water and sewer costs. Unit conversion gas volume conversion makeup water requirement for cooling tower psychrometric calculations. The number of tower tu water flow rate gpm x rating factor. Calculator is able to calculate the various process data like. By understanding how cooling tower systems function, facility owners and operators can operate and maintain their systems more.
To conserve water used for cooling tower makeup while controlling microbes, corrosion, and scale in the condenser water system. Water treatment cooling towers, evaporative condensers. Provide miscellaneous calculations like steam tables, unit conversion, psychrometric. K overall enthalpy transfer coefficient, lbhft2 a surface area per unit tower volume, ft2ft3 v effective tower volume, ft3 l water mass flowrate, lbh equation 2 basically says that at any point in the tower, heat and water vapor are transferred into the air due approximately to the difference in the enthalpy of the air at the surface of the water and the main. Dec 19, 2017 cooling towers are recirculating water systems used to remove heat from building air conditioning equipment and industrial processes. The water balance of a tower or cooling water system involves all of the water inputs and outputs associated with the operation of the system.
Cstn july 2003 l et s take a look at how to calculate cooling tower blowdown. How heat loads affect evaporative cooling tower efficiency. Bibliography of technical papers cooling tower water chemistry. Therefore, the maximum normal water makeup for a cooling tower system is. The water consumption the make up water of a cooling tower is about 0.
Cooling tower water discharge commercial best management. Cooling towers how to calculate cycles, blowdown, evaporation, makeup 2 replies here are the governing relationships for the makeup flow rate, the evaporation and windage losses, the drawoff rate, and the concentration cycles in an evaporative cooling tower system. The major concern during i study the cooling tower theory was how to computerize the cooling tower theory from the calculation of ntu to the cooling tower performance analysis. For cooling towers and evaporative condensers, conduct a onetime potable water analysis, in order to optimize cooling tower cycles.
Water quality guidelines water treatment a proper water treatment program, administered under the supervision of a competent water treatment specialist, is an essential part of routine maintenance to ensure the safe operation and longevity of evaporative cooling equipment, as well as. Process leaks, windage, and drift are really just forms of uncontrolled blowdown. Use this calculator to determine the potential water and cost savings for your cooling tower. Following items will be discussed and calculated in this article. If you read this book carefully, you can make any cooling tower design programs by yourself.
Then press your tab key to see how your water usage data changes. Oct 06, 2016 this feature is not available right now. The following chart specifies the maximun water make up requirement per model. Using performance data derived from the spx research and development center and independently tested. Ace sales training my documents the rav downloads technical data sheets multimedia. At these condi tions, the cooling tower rejects 15,000 btuih per nominal cooling tower ton. Use this handy calculator to approximate cooling tower water use and cycles of concendtration. This is where the rule of thumb for every t of 10 f, 1% of the recirculation rate must be evaporated to achieve this cooling comes from. The amount of water that is bled off by the water treatment system is usually less than or equal to the amount of water that evaporates. As this occurs, a small volume of water is evaporated, reducing the temperature of the water being circulated through the tower. Management of cooling tower blow down is necessary to prevent fouling and efficiently use the makeup water resource.
Baseline water flow requirements fixture energy policy act of 1992 flow requirement water closets, gpf lpf 1. Cooling tower makeup water article about cooling tower. Lets take a look one by one how to calculate each component. Cooling tower efficiency calculations cooling tower approach. United laboratories cycle smart cooling tower programs use the greenest, most powerful chemistry. A cooling tower is an essential piece of equipment in many production facilities used to bring down the temperature of the water used in many different process so it can be used again.
Evaporative cooling towers, like the advantage power tower series, provide cooling. Measure at least the five control parameters listed in table 1. For example, a singlepass cooling system uses 40 times more water than a cooling tower operated at 5 cycles of concentration to remove the same heat load. A nominal cooling tower ton is defined as cooling 3 gpm of water from 95f to 85f at a 78f entering air wetbulb temperature. When dealing with a cooling tower, to cool the incoming water being sprayed over the tower by 10 qf, then 1% of the flowrate over the tower must be evaporated. Obtain water analyses for the recirculating cooling water and makeup. Add an initial ecolyme dosage to the water circuit following the. This includes determination of cycle of concentration, evaporation loss, drift or windage loss, blow down water requirement makeup. The rating factor is a measure of the cooling job difficulty.
Cooling tower cycles of concentration as pure water is evaporated, minerals are left behind in the recirculating water. Steam tables based on iapws if97 condensate flash calculation steam desuperheating calculation. Marley fit selection software our new marley fit air delivery selection software takes into consideration the relationship among all cooling tower mechanical system components to recommend a complete system. Therefore, it likewise is independent of the cooling tower. Using soft water for cooling tower makeup water technology. Nov 25, 20 the drift rate for a new cooling tower equipped with best available drift eliminators would be 0. Ct makeup elevation h v w calculation authored and generated by ctc design, inc.
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