The technical data has been taken from a mechanical draft cooling tower. What is the working principle in the cooling tower. Cooling towers, wet cooling, dry cooling, aircooled heat. Drift eliminators are installed to prevent water entrained in the air from leaving the system. Principles and practice, third edition, aims to provide the reader with a better understanding of the theory and practice, so that installations are. Stanford, cooling towers principles and practice, 2nd ed.
Cooling towers overcome most of these problems and therefore are commonly used to dissipate heat from watercooled refrigera tion, airconditioning, and industrial process systems. Water flows perpendicular to the air through the fill by gravity. Here evaporation occurs, removing heat along with the evaporated water. They reject process heat from the cooling water to atmosphere and keep the water cool. The approach of this essential reference is practical and international, and it is based on 30 years of professional experience. The impact of ventilation cooling towers on plus energy houses in southern europe. These towers are larger in size compared to the package type cooling towers.
Cooling towers should not be downwind or adjacent to fired heaters, flare stacks, or any heatproducing items, as these raise the ambient air temperature and reduce the towers cooling efficiency. Cooling towers are heat removal devices used to transfer process waste heat to the atmosphere. Cooling tower basics and common misconceptions introduction in comparison with most other industrial equipments, the water cooling tower is a simple device, based on the direct contact of two of the earths most common substances. An assortment of formulas for the protection of cooling water systems possibly supplemented with zinc at the corrosive end of the spectrum and high performance polymers at the scaling end. Profusely illustrated, this handbook will enable professionals to understand the factors that may interfere and. Here we explain in full detail how cooling towers operate with example text, pictures, diagrams and principles. Cooling tower operation forced draught cooling towers use the evaporation of a liquid often water into air to achieve cooling. Cooling tower performance basic theory and practice subject. 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. When a requirement for free cooling is specified for a project utilizing cooling towers, certain considerations must be made from the very beginning of the project design. Is the companion field guide handbook to cooling water treatment principles and practices by colin frayne. Principles and practices by colin frayne isbn 9780820603704. Water conservation in cooling towers au best practice guidelines intent this document has been prepared to assist the owners and operators of cooling towers and evaporative cooling systems in reducing the water consumption of cooling systems while retaining required performance.
Cooling tower systems are an integral part of many refrigeration and process cooling systems across all industries, in particular the commercial property industry. Cooling towers 3rd edition 9780750610056, 9781483162744. 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. A plume is formed in these towers which is a cloud of very small droplets 1. General information above is an animation of a hyperbolic stacknatural draft cooling tower. A cooling towers function is to remove heat from a building or process application that generates heat and must be dissipated.
Field erected type cooling towers are usually preferred for power plants, steel processing plants, petroleum refineries, and petrochemical plants. Again, this will be a first issue releasing the actual engineering approach. Best practice co2 threshold given by cibse and ashrae are. Rutger botermans, peter smith, in advanced piping design, 2008. Examines the assessment, specification, installation, and maintenance of cooling towers. Types and performance evaluation, efficient system operation, flow control strategies and energy saving opportunities, assessment of cooling towers 7. Crossflow is a design in which the air flow is directed perpendicular to the water flow. Despite best practice guidelines available, it remains common to find examples of poorly designed and executed piping, which create a variety of hazards. Factors affecting the location of cooling towers, other than convenience to water supply and return, are the prevailing wind, noise, and access roads. Since heat exchange is relatively poor in air, the surface area need to be large to compensate. In simple terms, we can define it as an ecofriendly device that can reduce the temperature of the warmest water in the most efficient way at any source. Cooling tower efficiency calculations cooling tower efficiency calculation is described in this article. From thermodynamic principles, the outlet water temperature from the cooling tower.
The gives both long sides an equal intake of fresh air. Cooling tower wateris water circulated in an open system, such as the cooling tower and condenser of an airconditioning system or a turbine condenser. Finally, a case study on retrofitting of central chilled water system is presented in chapter 6. Principles and practice table of contents introduction. Cooling towers make use of evaporation whereby some of the water is evaporatednto a moving air i. The wetbulb temperature is a type of temperature measurement that reflects the physical properties of a system with a mixture of a gas and a vapor, usually air and water vapor. One helpful means to that end is the water cooling tower. This title is the companion guide to cooling water treatment. Develop and implement a water systems management program for the cooling tower meant to include all types of evaporative cooling equipment and associated water systems.
What is a cooling towers working principle, water cooling towers are widely used for thermal comfort in hospitals and hotels as well as in industrial areas. Cooling tower efficiency calculations cooling tower approach. The water efficiency principles contained within this. Classification based on heat transfer method wet cooling tower this type of cooling tower operates based on evaporation. It is then combined with makeup water, which replaces the evaporated water, and is sent through the system again. Each of these techniques has different principles of operation, strengths. The tower often consists of a sprinkler system which wets a highsurfacearea substrate plates continuously, while air flow through the chamber converts liquid to vapor. This paper presents detailed methodology of a induced draft cooling tower of counter flow type in which its efficiency, effectiveness, char acteristics are calculated. Best practice guide apply to typical cooling towers and operators. Cooling water treatment principles and practice water. The fundamental principles of cooling towers are to cool down the heated water of industrial equipment and processes. Cooling towers the development, practice, and performance of evaporative cooling systems or cooling towers have been described in numerous publications including some of those listed in the bibliography. Save up to 80% by choosing the etextbook option for isbn. The fundamental principal employed in accomplishing this removal of heat is the evaporation of water.
How cooling towers work w pictures, diagrams, principles 2016. Mechanical geothermal water cooling tower in south. Iii aircooled heat exchangers and cooling towers d. Cooling towers should be located with their small side toward the prevailing wind. In technical terms, cooling towers are engineered and designed based on a specified cooling load, expressed in refrigeration tons. First, special care must be taken when laying out the cooling towers to prevent recirculation due to poor tower location and prevailing winds.
A cooling tower is one of the larger items of equipment, in terms of ground area, that must be located on a site plan. In this handbook you will find many helpful formulas for use in the field such as formulas for. They reject process heat from the cooling water to atmosphere and keep the. Cooling tower plays a major role in chemical process industry. Accepted industry practice for bacterial control is the use. In practice the cooling tower efficiency will be in between 70 to 75%. The heat that is removed is called the latent heat of evaporisation.
Since the cooling towers are based on the principles of evaporative cooling, the maximum cooling tower efficiency depends on the wet bulb temperature of the air. A cooling tower s function is to remove heat from a building or process application that generates heat and must be dissipated. Mathie, chemical treatment for cooling water 6 colin frayne, cooling water treatment. 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. Air flows into the tower through openings in the bottom, and cools the entering hot water. Cooling towers principles and practice 3rd edition by g.
This section discusses hyperbolic stacknatural draft cooling towers, such as the one shown above in the animation. An introduction to cooling tower water treatment cedengineering. Marketing cooling water treatment xvii 1 cooling system and heat exchange essentials 1 1. Top ten worst practices cooling towers the poor design and installation of pipe work associated with cooling towers continues to be a concern across the industry.
Kroger encyclopedia of life support systems eolss 2. Nicolson, understanding cooling water treatment saves, authorhouse, 2004 ijser. The cooling tower must be adequately sized to reject this same amount of heat. Technical information for cooling towers using recycled water. As with all branches of engineering, new technology calls for a level of technical knowledge which becomes progressively higher.
Principles of cooling towers all cooling towers operate on the principle of removing heat from water by evaporating a small portion of the water that is circulated through the unit. Pdf 60 m3h nominal capacity cooling tower was designed, based on the required cooling water parameters in. The environment is friendly because when the hot water is cooled, the towers produce. Chilled water is cold water, circulated in a closed system, that serves as a medium for transferring cold temperatures for air cooling. Each one pound of water that is evaporated removes approximately. Sean mcgowan reports top ten worst practices cooling towers. Cooling towers are used to reject heat through the natural process of evaporation. Principles and practice, chemical publishing company incorporated ny, 1999 7 charles r. Cooling towers are a special type of heat exchanger that allows water and air to come in contact with each other to lower the. For modern, highefficiency cooling towers, drift is about 0. The cooling tower must be adequately sized to reject this same amount of heat to the atmosphere. Pdf design and performance analysis of the cooling tower in the. Refrigeration in cooling towers conductive heat flow general industrial and cooling water makeup contents. Many of these problems are preventable through proper cooling water chemistry treatment.
This system sends cooling water out of the equipment and into a pond or cooling tower, which is open to the atmosphere. Downtime for equipment repair or replacement is always costly. Intent in the foreword of cooling tower fundamentals published by marley cooling technologies, inc. Abstracta cooling tower is a heat rejection device. Brian ford describes the principles and current practice of this innovative approach to cooling in the hot dry regions of the world. Cooling towers, and their associated system components, are commonly used to provide comfort cooling for large commercial buildings including office buildings, retail. Pdf on sep 22, 2011, eusiel rubiocastro and others published optimal design of cooling towers find, read and cite all the research. If you read this book carefully, you can make any cooling tower design programs by yourself. Communication tower best practices osha 38770 6 2017.
The year before, the neighboring community had experienced outbreaks of legionnaires disease, and even though the hospitals cooling towers played no role in those outbreaks, the chance to increase protections against possible future exposures of the bacteria that cause the disease was an important consideration. This comprehensive book is the only one that addresses theory, practice, management, purchasing and marketing of cooling water systems in one volume. In this handbook you will find many helpful formulas for use in the field such. The cooling tower water efficiency principles documented within this.
One of our most useful resources is the mechanism of threshold treatment. Principles of heating, ventilation, and air conditioning in. Air flow enters one or more vertical faces of the cooling tower to meet the fill material. Cooling tower bureau of energy efficiency 5 syllabus cooling tower. 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. See the more detailed explanation of cooling towers systems.
This revised edition first, 1967 presents new developments in manufacturing practice and changes in construction such as the elimination of timber packing in favor of plastics and the use of new technology and designs of drift eliminators to avoid biological contamination, particularly by legionella. The emphasis is on the application of engineering principles, and features a tight integration of physical descriptions with a software program that allows performance to be directly calculated, with results that provide insight. A practical guide to cooling tower selection and operation by w stanford. Cooling towers quiz questions hvac certification practice tests. Guides and recommended procedures for water treatment.
In the wet cooling towers the air is in direct contact with water and the cooling is caused mostly by evaporation and is much more efficient. Address best environmental practices for heat transfer efficiency, equipment reliability, asset life expectancy, maintenance costs, minimization of water and energy. The year before, the neighboring community had experienced outbreaks of legionnaires disease, and even though the hospitals cooling towers played no role in those outbreaks, the chance to increase protections against possible future exposures of the bacteria that. Iron oxide, especially, contributes to fouling and deposition, which interfere with heat transfer. To assist installation personnel responsible for operating cooling systems, a list of lessons learned over the past 15 years has been assembled. While it comes hot from the tower but goes back cold to the industrial process. The operating principles of these devices are based on four essential. This revised edition first, 1967 presents new developments in manufacturing practice and changes in construction such as the. Airconditioning and mechanical ventilation acmv systems. Braun provides foundational knowledge for the behavior and analysis of hvac systems and related devices. The cooling towers at biogen idec are the largest users of water in the facility. Cooling towers make use of evaporation whereby some of the. This document is advisory in nature and informational in content.