The mass balance around a cooling tower as illustrated in the figure to the right is. Combining the mass flow equations with the energy equation leads to the final equation relating the mass flow rate of the dry air to the circulating cooling water of. Section b is devoted to cooling tower theory and calculations. Latent heat gain is the energy added to the space when moisture is added to the space by means of vapor emitted by the occupants, generated by a process or through air infiltration from outside or adjacent areas. The technical data has been taken from a mechanical draft cooling tower. 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. It works with all types of cooling towers and with different types of fill splash or film.
Heat load of the cooling water is indicated by the standard heat transfer equation. Cooling tower plays a major role in chemical process industry. Cooling tower calculations cooling water treatment. A cooling tower is a heat rejection device that extracts waste heat to the.
Cooling tower heat transfer fundamentals power engineering. Cooling tower bureau of energy efficiency 5 syllabus cooling tower. If heat load calculations are low, the cooling tower purchased will probably be too small. There are important cooling tower heat transfer fundamentals and modern. Cooling tower basics calculation formulas cooling tower. Cstn july 2003 l et s take a look at how to calculate cooling tower blowdown. The efficiency of this cooling tower system depends on climatic conditions, in particular the wetbulb temperature and the relative humidity of the ambient air. 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. System components include piping infrastructure, valves, pumps, heat exchangers, the cooling tower structure, and cooling. Hvac cooling load calculations and principles sensible heat gain is the energy added to the space by conduction, convection andor radiation.
As this occurs, a small volume of water is evaporated, reducing the temperature of the water being circulated through the tower. The merkel equation the fundamental equation of heat. 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. For the sake of this document, cooling tower systems include open recirculating circuit coolers, fluid coolers, and evaporative coolers, closed evaporative condensers. Cooling tower efficiency calculations cooling tower approach. Scribd is the worlds largest social reading and publishing site. Calculations for approach to wet bulb and cooling range. The term induced draft denotes that air is drawn by fans through the flow of falling water and up and out of the cooling tower. Calculations 419 cooling tower evaporation rule of thumb by james mcdonald, pe, cwt originally published. Cooling tower evaporative cooling system measurement and. Cooling tower cycles of concentration as pure water is evaporated, minerals are left behind in the recirculating water. Cooling tower sizing can simply be done by graphical methods. Cooling tower evaporative cooling system measurement. Several investigators have substantiated the effect of hot water temperature and air velocity on the counter flow tower.
Almost 14 th of makeup water water added in a cycle to substitute water losses in a cooling tower is dissipated 25. Cooling towers overcome most of these problems and therefore are commonly used to dissipate heat from watercooled refrigera tion, airconditioning, and industrial process systems. Process leaks, windage, and drift are really just forms of uncontrolled blowdown. Cooling tower makeup water calculation with example. Since no work is done and no heat transfered externally, the cooling tower energy equation reduces to an enthalpy balance equation. Cooling tower calculations water technology report. This amount of heat could theoretically melt 1 ton of ice in. The cooling effect occurs because some of the water evaporates into a stream of air in contact with the water within the cooling tower. 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. In summer the ambient air wet bulb temperature raises when compared to winter thus limiting the cooling tower efficiency.
Drift eliminators are installed to prevent water entrained in the air from leaving the system. The water consumption rate of a cooling tower system is only about 5% of that of a oncethrough system, making it the least expensive system to. Pdf a simplified procedure for calculating cooling tower. How to calculate the cooling tower capacity in tr quora. If you read this book carefully, you can make any cooling tower design programs by yourself. The present paper is a detailed methodology for thermal design of cooling tower. Estimate evaporation loss and makeup water requirements article pdf available april 2017 with 9,149 reads how we measure reads. Other types of water losses were therefore neglected. The technical data is taken for mechanical draft cooling tower.
Pdf 60 m3h nominal capacity cooling tower was designed, based on the required cooling water parameters in. The fanlaws can be used topredi ctthe pe rformance ofa towerwitha nonstandard motor. Pdf design and performance analysis of the cooling tower in the. 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.
Water savings of cooling tower efficiency measures for use in performance contracts. Cooling tower efficiency calculations chemical engineering site. Cooling tower design calculation software videosmultiprogram. F o r m u l a s a n d t a b l es formulasandtables fanlaws. Cooling tower, design equation, mass transfer, heat transfer. Again, this will be a first issue releasing the actual engineering approach of cooling tower with the examples in the world. Cstn march 2005 y ou ve all heard this rule of thumb. The bench top cooling tower behaves in a similar manner and has similar components to a. Section a on cooling tower practice covers topics such as the design and operation of cooling towers.
Theoretically, if the controlled bleed is shut off, the maximum cycles of concentration achievable in a cooling tower is limited by the percent evaporation and percent windage. Cooling tower process is generally related with vapor pressure of water and humidity. A very important concept for understanding cooling tower heat transfer is that of wet bulb temperature, which is the lowest temperature that can be achieved by evaporative cooling. Calculating the tons for a cooling tower requires you to understand some basic information about it works. Rp m 2 rp m 1 cfm 2 c fm 1 staticpressure 2 static pressure 1 cfm 2 cfm 12. In this article explained about basic concepts of cooling tower, types of cooling towers, formula for cooling tower efficiency. Cooling tower fundamentals spx cooling technologies. How to calculate tons of cooling for a cooling tower sciencing. Some additional calculation such as water makeup, fan and. If heat load calculations are low undersized equipment will be. The evaporation can by estimated from a heat balance around the cooling tower e 0. Cooling load calculations and principles ced 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. The performance of cooling tower fans depends on the calculation degree of static pressures at the cooling tower.
A critical element of operation at many combined cycle power plants is energy transfer in one or more cooling towers. 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. 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. For the love of physics walter lewin may 16, 2011 duration. A simplified calculation procedure of tower coefficient is presented. Cooling towers are a very important part of many process plants. Observe how much makeup water is required for one cooling tower m qm. Dec 04, 2017 for modern mechanical draft cooling towers with drift eliminators, the impact of windage on the overall bleed rate is minimal and often ignored in cooling tower calculations. Types and performance evaluation, efficient system operation, flow control strategies and energy saving opportunities, assessment of cooling towers 7. An opencircuit cooling tower, commonly called a cooling tower, is a specialized heat exchanger in which two fluids air and water are. Design of mechanical draftcooling tower and determination of. To simulate an industrial cooling tower and study its performance based on.
The required cooling tower design and size will be a function of following values. Cooling tower efficiency calculations cooling tower efficiency calculation is described in this article. The procedure is then applied to a popular cooling tower model, to illustrate. Understanding the basics of cooling tower heat transfer. Calculations 417 cooling tower blowdown equation by james mcdonald, pe, cwt originally published. Jul 06, 2017 cooling tower thermal design manual sharif cooling tower thermal design manual cooling tower technical site of daeil aqua co. They reject process heat from the cooling water to atmosphere and keep the water cool. If the calculations are high, oversized, more costly equipment will result.
Those theories are briefly described in this guideline to provide the basic understanding of its calculation. Oct 10, 2018 for the love of physics walter lewin may 16, 2011 duration. The water exits the cooling tower and is sent back to the exchangers or to other. Department of energy assistant secretary for resource. Calculate a ton of cooling load using this formula.
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