Cooling tower sizing can simply be done by graphical methods. Cooling tower control based on approach computrols. Design of mechanical draftcooling tower and determination of. Principles and practice, third edition, aims to provide the reader with a better understanding of the theory and practice, so that installations are correctly designed and operated. Dutchess community college cooling tower maintenance program and plan april 1, 2016 3 general. Water, including make up water composition quality, availability of pretreatment and. May 19, 2017 cooling tower makeup water calculation with example may 19, 2017 may 19, 2017 rifka aisyah utility system its been a while since the last time i write an article about utility system. Coc or the cycles of concentration is an abbreviation, used when talking about cooling water or cooling tower water. A centrifugal pump moves water, known as condenser water, between the chiller in the basement and the cooling tower on the roof. A cooling tower is a heat rejection device used to lower the temperature of the return cooling water. So the colder the water, the better the kw efficiency.
Cooling water system design fundamentals water technology. Cooling tower types cooling towers fall into two main categories. Oncethrough cooling was a common design feature for large power plants in the last century, as the process could effectively supply the high volumes of water needed for turbine exhaust steam. Hvac use of a cooling tower pairs the cooling tower with a water cooled chiller or water cooled condenser. The cooling water network design can be carried out using the cooling water mains method or automated design method. This is true whether the heat is generated in a critical process reactor or in an executive office building. When we use water to lower the operating temperature of equipment or entire plants, it is called cooling water. A water conservation guide for commercial, institutional and industrial users new mexico office of the state engineer, 1999 the purpose of a cooling tower is to conserve water by recycling it through the chiller. The higher the wet bulb, the harder a cooling tower has to work to evaporate enough water to maintain set points. The cooling tower should have a water treatment program, and must be thoroughly cleaned on a regular basis. A cooling tower is heat removal device that uses water to transfer process waste heat into the atmosphere. In this sense, a cooling tower is a water conservation device.
Some water evaporates into the airstream causing cooling. They represent a relatively inexpensive and dependable means of removing low grade heat from cooling water. A survey of wet cooling tower literature was performed to develop a simplified method of cooling tower design and simulation for use in power plant cycle optimization. For a given cooling tower design, the quantity of water to be treat. The following cooling towers are present on dutchess community college campus. For premises located outside the listed designated areas, applications for joining the fwct scheme for their fresh water cooling tower installations are also welcomed and will be considered on a casebycase basis in consultation with water supplies department wsd on adequacy of fresh water supply. This new edition looks at how climate change and green designs have significantly impacted the selection of refrigerants and the application of chilled water systems. Optimal design of cooling water systems intechopen. For the tower piping circuit, the pump must overcome the piping flow friction loss. An introduction to water cooling towers ced engineering. It utilizes air instead of water so named as dry cooling tower. So, for our example drift would amount to approximately 1 gpm. The software program can be used for the analysis of existing towers or for the preparation of specifications for new towers.
Best management practice and guidance manual for cooling. Once a tower characteristic has been established between the plant engineer and the manufacturer, the manufacturer must design a tower that matches the value 7. In a counterflow cooling tower, water sprays are used to distribute the warm water see figure 8. In a short summary, the purpose of a cooling tower is to cool down water that gets heated up by industrial equipment and processes. 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. Section a on cooling tower practice covers topics such as the design and operation of cooling towers. Cooling tower noise sources fan noise low frequency blade passage tone below 63 hz spraying and splashing noise of water higher frequencies motor, belts or gearbox noise intake noise level typically 5 db less than discharge noise increases with fan speed. Coc cycle of concentration in cooling water system. The largest cost driver of factory assembled cooling towers is the primary material that forms the casing of the cooling tower. For the purpose of tower design, a tower with a smaller approach small delta between basin water temperature and wet bulb temperature is considered superior. The difference between the leaving water temperature and the entering air.
The technical data is taken for mechanical draft cooling tower. The technical data has been taken from a mechanical draft cooling tower. 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. Again, this will be a first issue releasing the actual engineering approach. A cooling tower is a heat rejection device that rejects waste heat to the atmosphere through the cooling of a water stream to a lower temperature. During the cooling tower working process, small volumes of water evaporate, lowering the temperature of the water thats being circulated throughout the cooling tower.
Fundamentals, application, and operation, second edition explores the major improvements in recent years to many chiller and cooling tower components that have resulted in improved performance and lower operating costs. How much does a cooling tower water treatment system cost. The fan deck supports the motor and fan of the water. The merkel equation the fundamental equation of heat. All have been registered by the dutchess community college physical plant hvac supervisor with the nys department of health. This type of cooling tower operates by convective heat transfer through a surface which separates fluid from the air. The maintenance program and plan mpp is a detailed plan customized for a cooling tower system that describes operational and administrative strategies and process control measures to be taken to prevent and control the growth of legionella requirements. Design and operation considerations cooling towers are a very important part of many chemical plants. This new edition looks at how climate change and green designs have significantly impacted the selection of refrigerants and the application of chilled water.
The chiller adds heat to the condenser water and the cooling tower cools it down by rejecting this into the atmosphere. In any case where unwanted heat is generated, it is necessary to design a suitable cooling system that is capable of absorbing. Also, the state of the outlet air from the cooling tower can be fully. The theory of heat exchange in wet cooling towers is briefly summarized. Cooling tower plays a major role in chemical process industry. There is no single method of treating cooling water. Cooling tower design companies cooling tower design. A psychromehic analysis of the air passing through a cooling tower illustrates this effect figure 2.
Increasing cooling water velocity, which keeps the water cooler using compressed air to air rumble the heat exchanger inlet water on a periodic basis to dislodge and remove scales and deposits modifying the exchanger design so that the cooling water is on the tube side, promoting higher velocity. With the new cooling water network design figure 7, the cooling tower manages the. A cooling tower is a heat rejection device which rejects waste heat to the atmosphere through the cooling of a water stream to a lower temperature. Cooling tower efficiency calculations cooling tower efficiency calculation is described in this article. A critical element of operation at many combined cycle power plants is energy transfer in one or more cooling towers. Cooling tower calculations software program is a powerful, user friendly, software program for the analysis of induced, mechanicaldraft, counterflow cooling towers. C is usually specified for the water entering the cooling tower douglas. This new edition looks at how climate change and green designs have significantly. The water exits the cooling tower and is sent back to the exchangers or to other units for further cooling. Scale control involves the maintenance of the cooling water chemistry within prescribed limits to prevent the over saturation of the water with mineral salts. Materials of construction delta cooling towers, inc. Hvac water chillers and cooling towers boilersinfo. Code of practice for fresh water cooling towers part 1. Limit water velocity at basin outlet to pumps to 1 to 2 fps maximum.
For large cooling towers especially power plants, water treatment is the key area for energy conservation. As this occurs, a small volume of water is evaporated, reducing the temperature of the water being circulated through the tower. The goal is to assure the implementation of water cooling systems which will satisfy all design and. Mar 04, 2016 how water is used in a cooling tower system the diagram below illustrates water use in a cooling tower system. The growth of legionella is promoted by inadequate water flow, such as in water stagnation in pipes that are only seldom used. Cooling towers vary in size and design based on the cooling load of a building. Which is why a cooling tower adds in a few other factors to the equation.
A primary goal of cooling water treatment programs is to prevent the formation of scale deposits in heat transfer equipment, cooling tower fill, and in lowflow areas of the system. Cooling tower heat transfer fundamentals power engineering. Abstract this paper presents detailed methodology of a induced draft cooling tower of counter flow type in which its efficiency, effectiveness, characteristics are calculated. Cooling tower makeup water calculation with example.
Cooling tower fundamentals spx cooling technologies. Typical closed loop cooling tower system is shown in figure 7. The fan deck supports the motor and fan of the water spray system. It must also provide the energy head necessary to raise water from a low to a higher static head level. Our cooling towers are heattransfer units, used to remove heat from any water cooled system. If you read this book carefully, you can make any cooling tower design programs by yourself. Water flows perpendicular to the air through the fill by gravity. In order to keep your production flowing smoothly and. All industrial cooling water systems function for one purpose to remove unwanted heat. They aid in industries such as plastics, dry cleaning, and more, rely on cooling towers to remove heat from environment or equipment. From the experimental study the efficiency of the cooling tower and cooling tower characteristics are higher in vowmp due to higher contact area of water to air. Efficient reuse of cooling water increases the operating range of the tower and also reduces the operating cost for water pumping and air supply, which is another benefit to tower operation. Air enters at the ambient condition point a, absorbs heat and mass moisture from the water.
Towers can be constructed from either wood or steel in a variety of styles and heights. 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 towers may either use the evaporation of water to remove process heat and cool the working fluid to near the wetbulb air temperature or, in the case of closed circuit dry cooling towers, rely solely on air to cool the working fluid to near. Im sure you guys are pulling out your favorite new scotch terminology at cocktail parties, and using those distillation terms in every saturdays crossword, but now that weve covered the basics, i wanted to focus in on a certain kind of distillationthe kind that takes place in the pot still. Therefore, psychometry is the basis for analysis of heat transfer i n wet cooling towers. The goal of this book is to provide the hvac designer, engineers the building owner and his operating and maintenance staff, the architect, and the mechanical contractor with definitive and practical information and guidance relative to the application, design, purchase, operation, and. The required cooling tower design and size will be a function of following values. With the new cooling water network design figure 7, the cooling tower manages the increased heat. The water sprays through nozzles onto banks of material called fill, which slows the flow of water through the cooling tower, and exposes as much water surface area as possible for maximum air water contact. In some forced draft counter flow design, however, the water at the bottom of the fill is. Understanding the basics of cooling tower heat transfer. Feb 6, 20 distillation equipment, greek alchemical manuscript. Using colder condenser water reduces the chiller kw by 1% to 1. Materials of construction manufacturers of cooling towers.
The cooling load is determined by the size of a building from which heat needs to be extracted. Operation of a cooling tower choose and design a system that meets your process requirements. The proposed debottlenecking procedure enables the cooling tower to manage the increased heat load by changing the network design from parallel to series arrangements. This material not only contains the water being recirculated through the cooling tower but also must structurally support a mechanical fan system, internal components, and water weight including a sump full of water.
Pdf design and performance analysis of the cooling tower in the. Cooling towers can cycle water numerous times before the water becomes saturated and must. In this article explained about basic concepts of cooling tower, types of cooling towers, formula for cooling tower efficiency. All cooling towers operate on the principle of removing heat from water be evaporating a small portion of water that is recirculated through the unit. The cooling tower should be located away from fresh air intakes, operable windows, kitchen exhaust, and prevailing winds directed toward public areas. It transfer heat to the atmosphere without evaporation and consumption of water is relatively less. Elevated water tanks and tanks on towers provide for a combination of pressurized water from gravity feed as well as a highly visual statements. Wet cooling towers can be natural the therefore, the design of mechanical d r a f t cooling towers is the in wet cooling towers, a i r and water are intimately mixed to provide heat trans fer. Best management practice and guidance manual for cooling towers. Treating cooling tower water properly is essential to the success and efficiency of your process. It is most suitable for cooling of processing liquid. Cooling water problems and solutions ced engineering. An introduction to cooling tower water treatment guyer, j. Apr 08, 2015 the fundamental component of most open recirculating cooling systems is the cooling tower.
Pdf design and performance analysis of the cooling tower. Cooling tower efficiency calculations cooling tower approach. Closed loop cooling tower system the makeup water source is used to replenish water lost to evaporation. Air flow enters one or more vertical faces of the cooling tower to meet the fill material. Selection of water treatment program for a specific system depends on.
Scale and fouling control in cooling tower systems water. Cooling tower basics calculation formulas cooling tower. A simple model to help understand water use at power plants anna delgado and howard j. They reject process heat from the cooling water to atmosphere and keep the water cool. In cooling towers with wellengineered mist eliminators, a common design drift rate is 0.
The lg ratio of a cooling tower is the ratio of the liquid water mass flowrate l to gas air mass flowrate g. The makeup water source is used to replenish water lost to evaporation. Effective thermal design of cooling towers a stepbystep approach to cooling tower design, with an example calculation to make it clear jonny goyal air liquide engineering and construction, lurgi india various misconceptions arise when it comes to the thermal design of cooling towers. Industries such as power, pulp and paper, oil and gas, ethanol, steel, mining, leather and manufacturing. Pdf design and performance analysis of the cooling tower in. Hvac water chillers and cooling towers fundamentals, application, and operation by herbert w. Cooling tower basins international district energy. So set the low limit on the to setpoint based on what the chillers can handle. Organic growth, fouling, scaling, corrosion, and water scarcity are all challenges that can reduce plant productivity and require costly equipment replacements down the road, but how much does a cooling tower water treatment system cost.
Hot water from heat exchangers is sent to the cooling tower. The power plants heat rate depends on the fuel type used and the specific power plant design. Cooling tower process is generally related with vapor pressure of water and humidity. Distillation equipment, greek alchemical manuscript.
Cooling towers have certain design values, but seasonal variations require adjustment and tuning of water and air flowrates to get the best cooling tower effectiveness. Cti publications code tower standard specifications. Kim and smith 2003 presented a paper on retrofit design of cooling water systems in which pressure drop. Cooling water treatment for controlling suspended solids, algae growth, etc.
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. Oct 02, 2016 consider the cooling tower on top of a typical office type building. The economic optimization of recirculating cooling water systems includes. The coc specifies, how often a fresh water added into the loop, can be used or pumped around, before the water has to blown down or bleed off from the cooling. With the new cooling water network design figure 7, the cooling tower manages the increased heat load by changing the network design. Some additional calculation such as water makeup, fan and. Air is drawn into the intakes on the sides of the unit and passes through a stream of water. The primary purpose of the tower is to cool water so it can be reused. Section b is devoted to cooling tower theory and calculations. Cooling tower approach is the difference in temperature of the water entering the basin cold and the wet bulb temperature. Plant engineers reference book second edition, 2002. In a cooling tower, the water enters warm and leaves cooler, and the air enters cool and leaves warmer. The standard for vibration limits in water cooling towers provides cooling tower owners and manufacturers a specification for the acceptable mechanical vibration levels in new cooling towers. Those theories are briefly described in this guideline to provide the basic understanding of its calculation.
The present paper is a detailed methodology for thermal design of cooling tower. In many tower designs, the cold water basin is beneath the entire fill. A simple model to help understand water use at power plants. Design, installation and commissioning this code of practice was prepared to promote the proper use of fresh water cooling towers with guidelines for cooling tower design, installation, testing, commissioning, operation and maintenance in order to meet the energy efficiency objective with due. Cooling towers may either use the evaporation of water to remove process heat and cool the working fluid to near the wetbulb air temperature or. Crossflow is a design in which the air flow is directed perpendicular to the water flow. There are important cooling tower heat transfer fundamentals and modern. Large propeller fan located on top of unit discharging upward. In this blog, were going to define what those set points are, how cooling towers are rated, and finally how these factors impact the cooling tower size and operation for a given application. Concrete basics, materials, selection in design and repair. Lastly, cooling towers can cool water to within 4 to 5f of the ambient wetbulb temperature, or about 35f lower than can aircooled systems of reasonable size.
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