The cooling tower efficiency program requires customers to register their cooling towers with austin water and submit annual inspection forms. Ajit prasad dash1, kishor kumar panda2, ajay kumar yadav3. Section 1 laboratory data data from the laboratory data sheet are entered into the spreadsheet in the same order as they appear on the data sheet. Cooling towers supply cold water through an evaporative process described below. Cooling tower efficiency calculations chemical engineering site. When you sign up, we offer you a 1day free trial of 50 calculations. Water efficiency audits 9 cooling tower water audit checklist 10 1. The merkel theory overcomes this by combining the two into. As the water evaporates, the air absorbs heat, which lowers the temperature of the remaining water. Design of mechanical draftcooling tower and determination of. Cooling tower spreadsheet details details of the excel spreadsheet are presented here. Also known as cycles of concentration ratio, a cycle of concentration is the ratio of the dissolved minerals in the recirculating water compared to the dissolved minerals in the fresh water makeup of a cooling tower. 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.
Cooling tower basics calculation formulas cooling tower efficiency in this article explained about basic concepts of cooling tower, types of cooling towers, formula for cooling tower efficiency. If heat load calculations are low, the cooling tower. Drift is entrained water in the tower discharge vapors. Blowdown discards a portion of the concentrated circulating water due to the evaporation process in. Oct 17, 2016 although cooling towers are generally some of the most costeffective cooling mechanisms as compared to other cooling technologies such as many dry air cooling systems, it is still important to monitor your industrial cooling tower efficiency and run it as seamlessly as possible. Design of mechanical draftcooling tower and determination.
Austin water developed this program to help customers. Cooling tower efficiency program frequently asked questions. Mar, 2012 cooling tower design calculations posted in student. The theory of heat exchange in wet cooling towers is briefly summarized.
F o r m u l a s a n d t a b l es formulasandtables fanlaws. Cooling tower plays a major role in chemical process industry. If a cooling tower is discharging blowdown from the cooling tower basin or cooling water supply pipe, a simple piping change to discharge blowdown water from the cooling water piping returning hot water to the tower can provide a 12% improvement in the energy efficiency of the hvac cooling system. The fanlaws can be used topredi ctthe pe rformance ofa towerwitha nonstandard motor.
What is the cooling capacity in tr of a cooling tower for. Some parameters of the column operation are then calculated. The technical data is taken for mechanical draft cooling tower. Again, this will be a first issue releasing the actual engineering approach of cooling tower with the examples in the world. Therefore, it likewise is independent of the cooling tower. 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.
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. Chemical engineering site already published articles on cooling tower components and cooling tower efficiency calculations. L mass flow of water entering the cooling tower lbmin t. All of the required cooling water was assumed to be makeup water, with the. Effectiveness or efficiency of the cooling tower has been improved during part load operation. 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. The mass balance around a cooling tower as illustrated in the figure to the right is. How to increase your industrial cooling tower efficiency. Hi, i am an engineering student, and i am working on a cross flow induced draft cooling tower. Calculations 417 cooling tower blowdown equation by james mcdonald, pe, cwt originally published. When water evaporates, it absorbs latent heat of vapourization from the water and thereby causing the remaining water temperature to drop. How to calculate cooling tower efficiency as intervie view. Performance analyses of counterflow closed wet cooling towers. A1 analysis of cooling tower data a2 damper position fill it in here a3 date due fill it in here a4 see word spreadsheet file a5 for details.
The tower characteristic is determined by the ratio of range and logmeanenthalpy difference. Heat load of the cooling water is indicated by the standard heat transfer equation. Combine formula 5 and 6, we can calculate the relationship between. Cooling tower is used to reduce the temperature of hot water stream. Evaporation loss and effectiveness are two important performance parameters of cooling tower. Cooling tower performance calculations are usually performed numerically.
Cooling tower efficiency calculations cooling tower efficiency calculation is described in this article. This amount of heat could theoretically melt 1 ton of ice in 24. Optimization of the operating conditions for cooling tower applications in cooling water is extremely significant in order to get the most energy efficient operating point for these systems. This process provides significant cooling to the remaining water stream that collects in the tower basin where it can be. B7 a8 a dashed line below the title in a7 b8 test run a9 h 2 o rate, litersmin b9 a data entry 10. Cooling tower is an essential piece in most of the chemical process industries and in hvac applications. Cooling tower design calculations student cheresources. Sep 17, 20 if a cooling tower is discharging blowdown from the cooling tower basin or cooling water supply pipe, a simple piping change to discharge blowdown water from the cooling water piping returning hot water to the tower can provide a 12% improvement in the energy efficiency of the hvac cooling system. They reject process heat from the cooling water to atmosphere and keep the water cool. The circulating water flow is determined by the number of pumps running and the pressure drop in the overall circulating water system. Evaporation rate gpm water flow rate gpm x range f x 0. Although cooling towers are generally some of the most costeffective cooling mechanisms as compared to other cooling technologies such as many dry air cooling systems, it is still important to monitor your industrial cooling tower efficiency and run it. This cooling tower quiz module covers the design, calculations, operations and cooling water treatment etc which will be a refresher for the experience and an eyeopener for the fresh chemical engineers.
If you read this book carefully, you can make any cooling tower design programs by yourself. Cooling tower efficiency calculation is described in this article. Energy efficiency of cooling towers may 9, 2018 wednesday 7. Nomenclature a area m2 cp specific heat at constant pressure kjkg k. It is mainly used in air conditioning plants, chemical plants etc. 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. Cooling tower bureau of energy efficiency 9 figure 7. Attend this class, designed for hvac professionals, and explore efficiency improvements and the tradeoff between cooling tower size and energy savings. How to optimize the energy efficiency of cooling towers back to news when evaluating the success of any piece of industrial equipment, the main thing many people consider is the equipments priceperformance ratio how much it costs to operate the equipment weighed against with its ability to do its job, or simply called efficiency. Calculation of effect of cycles of concentration on amount. Cstn july 2003 l et s take a look at how to calculate cooling tower blowdown. The evaporation rate is approximately 2 gpm per 1 million btuhr of heat rejection. How to optimize the energy efficiency of cooling towers. Department of energy idaho operations office idaho national engineering laboratory this is an informal report intended for use as a preliminaryor working document work supported by the u.
Cooling tower efficiency calculation basic dtls youtube. Cooling tower efficiency calculations free download as pdf file. The cooling capacity of a tower is the heat rejected kcalh or tr refrigeration tons. Department of energy assistant secretary for resource. 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.
May 02, 2018 how to calculate cooling tower efficiency as intervie view. Meet cooling tower water efficiency standards and equipment requirements. High efficiency mechanical draft towers cool the water to within 5 or. The number 500 is a constant, therefore is independent of the cooling tower. Simplifications of the calculations are made and discussed. The mixing of warm water and cooler air releases latent heat of vaporization, causing a. Cooling tower evaporative cooling system measurement and. 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. Combining equations 53, 54 and 55, we can calculate the water consumption,wr. The present paper is a detailed methodology for thermal design of cooling tower. The equivalent ton on the cooling tower side actually rejects about 15000 btuh due to the heatequivalent of the energy needed to drive the chillers compressor.
Following items will be discussed and calculated in this article. Cooling tower systems include all components that provide comfort cooling by rejecting heat to the atmosphere through the evaporative process. Almost 14 th of makeup water water added in a cycle to substitute water losses in a cooling tower is dissipated 25. Save money on water and wastewater bills by identifying potential. Test your knowledge on cooling tower online quiz chemical.
How to calculate tons of cooling for a cooling tower sciencing. This manual is not intended to be allencompassing and thoroughly definitive. An hvac, or heating, cooling and air conditioning units operation is one of the most essential factors to think about when running industrial, commercial or residential property applications. Tonnage duty calculator flow gallons per minute hot water temperature f. This useful and easy program let you quickly and securely perform calculations for the design of a new cooling tower project, upgrade the performance of an existing counterflow tower and verify its efficiency and working conditions. Cooling tower efficiency portland general electric. Is it possible to perform the complete calculations. Again, this will be a first issue releasing the actual engineering approach. Calculating the tons for a cooling tower requires you to understand some basic information about it works.
Apr 08, 2018 cooling tower efficiency calculation is described in this article. In this paper, a simple differential equation for counter flow wet cooling tower is solved analytically taking into consideration the nonlinear dependency of the saturated air enthalpy on temperature. Process leaks, windage, and drift are really just forms of uncontrolled blowdown. This cooling tower quiz module covers the design, calculations, operations and cooling water treatment etc which will be a refresher. Cooling tower extracts heat from the condenser water by two modes.
Looking for ways to improve the efficiency of your cooling tower. Germany, had solved this problem by combining the two heat trans fer processes into. A cooling tower is heat removal device that uses water to transfer process waste heat into the atmosphere. Nov 22, 2014 try our neri calculator tool for free. Many researchers frequently recommended solid windbreakers to improve the cooling efficiency. Water efficiency reporting 12 cooling tower water audit report 12 audit comments 14 1. Calculate a ton of cooling load using this formula. Multiply the evaporation rate by the appropriate correction factor in the table below to calculate the makeup water. The evaporation rate is approximately 3 gpm per 100 tons of refrigeration. Nov 30, 2016 chemical engineering site already published articles on cooling tower components and cooling tower efficiency calculations. Cooling tower efficiency cooling tower efficiency can be expressed as efficiency 100t1t2t1t3 where t1 inlet temperature of water to the tower t2 outlet temperature of water from the tower t3 wet bulb temperature of air. Cooling tower efficiency calculations cooling tower approach. Natural draft wet cooling hyperboloi d towers at didcot power station, uk 1. Cooling tower makeup water flow calculation rea hvac.
How to calculate tons of cooling for a cooling tower. Understanding key components of cooling towers and how to improve water efficiency. This website and the incorporated cooling tower water efficiency calculator have been developed by airah with support from a wide range of industry stakeholders, water corporations and the victorian government. I know the inlet and outlet temperature of water, volume flow rate of water and the heat load desired from the cooling tower. An introduction to the use and construction of cooling towers is given. Seawater cooling tower drift rate the drift rate for a new cooling tower equipped with best available drift eliminators would be 0. These reasons combine to explain why evaporative cooling towers are smaller and. Cooling tower fundamentals spx cooling technologies. Cooling tower design calculations posted in student. Cooling tower basics calculation formulas cooling tower. Design of mechanical draftcooling tower and determination of thermal efficiency prof.
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