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Nimesh Tailor
Nimesh Tailor

Cooling Tower Theory and Calculations: Using the Cooling Tower Institute Blue Book as a Reference



- Purpose: Why is the blue book important for cooling tower design, operation and maintenance? - Content: What are the main topics covered in the blue book? H2: Cooling tower design - Types of cooling towers: Natural draft, mechanical draft, induced draft, forced draft, etc. - Cooling tower components and construction materials: Fill, drift eliminators, nozzles, fans, etc. - Cooling tower performance and efficiency: Heat transfer, evaporation, psychrometry, etc. - Cooling tower sizing and selection: Factors to consider, methods and formulas, charts and tables, etc. H2: Cooling tower operation - Cooling tower water quality and treatment: Sources of water, contaminants and problems, chemical additives and inhibitors, etc. - Cooling tower water balance and control: Makeup water, blowdown water, cycles of concentration, etc. - Cooling tower energy consumption and optimization: Fan power, pump power, heat rejection, etc. H2: Cooling tower maintenance - Cooling tower inspection and testing: Visual inspection, performance testing, vibration analysis, etc. - Cooling tower cleaning and disinfection: Methods and frequency, biofilm and legionella prevention, etc. - Cooling tower repair and replacement: Common problems and solutions, life cycle analysis, etc. H1: Conclusion - Summary: Recap the main points of the article - Recommendations: Provide some tips and best practices for cooling tower users - References: List the sources used in the article Table 2: Article with HTML formatting What is the cooling tower institute blue book?




Cooling towers are devices that use water to transfer heat from a process or a building to the atmosphere. They are widely used in industrial applications such as power plants, refineries, chemical plants, etc., as well as in commercial applications such as air conditioning systems, refrigeration systems, etc.




cooling tower institute blue book pdf



Cooling towers are complex systems that require proper design, operation and maintenance to ensure optimal performance and efficiency. To help cooling tower users achieve this goal, the Cooling Tower Institute (CTI) has published a comprehensive guide called the Blue Book.


The CTI is a non-profit organization that was founded in 1950 to promote the interests of the cooling tower industry. The CTI provides technical standards, certification programs, educational materials and research activities related to cooling towers.


The Blue Book is one of the most authoritative and widely used references for cooling tower practice. It covers all aspects of cooling tower principles and practice, from basic theory to practical applications. The Blue Book is updated periodically to reflect the latest developments and innovations in cooling tower technology.


The Blue Book consists of three sections:



  • Section A covers cooling tower practice topics such as types of cooling towers, cooling tower components and construction materials, practical aspects of tower selection, industrial applications and water quality and treatment.



  • Section B covers cooling tower theory and calculations topics such as psychrometry, heat transfer theory and calculations, calculations when selecting tower size for a given duty and the use of charts for calculation of cooling tower duties.



  • Section C covers data and tables topics such as the basis of the SI system of units and meteorological tables and data as well as data on specific heat capacity of some common substances.



The Blue Book is an essential resource for anyone who is involved in cooling tower design, operation or maintenance. It provides valuable information and guidance that can help improve cooling tower performance and efficiency.


Cooling tower design




Cooling tower design is a critical step in ensuring that a cooling tower meets the required heat rejection duty and operates efficiently. Cooling tower design involves selecting the type of cooling tower, determining the size of the cooling tower and choosing the appropriate components and materials for the cooling tower.


Types of cooling towers




Cooling towers can be classified into two main categories based on the mode of air movement: natural draft and mechanical draft.


Natural draft cooling towers rely on the natural buoyancy of warm air to create air flow through the tower. They are typically tall structures with a hyperbolic shape that creates a chimney effect. Natural draft cooling towers are suitable for large heat rejection duties and have low operating costs, but they require a lot of space and have high initial costs.


Mechanical draft cooling towers use fans to force or induce air flow through the tower. They are usually smaller and more compact than natural draft cooling towers and can be installed in limited spaces. Mechanical draft cooling towers can be further divided into two types based on the direction of air flow: forced draft and induced draft.


Forced draft cooling towers have fans located at the base of the tower that blow air into the tower. The air then passes through the fill and exits at the top of the tower. Forced draft cooling towers have a uniform air distribution and a low risk of recirculation, but they have a high fan power consumption and a high noise level.


Induced draft cooling towers have fans located at the top of the tower that suck air out of the tower. The air then enters the tower from the sides and passes through the fill. Induced draft cooling towers have a low fan power consumption and a low noise level, but they have a non-uniform air distribution and a high risk of recirculation.


Cooling tower components and construction materials




Cooling towers consist of several components that perform different functions. The main components of a cooling tower are:



  • Fill: The fill is the material that provides a large surface area for contact between the water and the air. The fill can be either splash type or film type. Splash type fill breaks up the water into droplets that splash on each other and on the fill surface, increasing the water-air contact time and area. Film type fill forms a thin film of water that flows over the fill surface, increasing the water-air contact area and enhancing heat transfer. The fill material can be either plastic or wood, depending on the water quality and temperature.



  • Drift eliminators: The drift eliminators are devices that prevent water droplets from escaping the tower with the exhaust air. The drift eliminators reduce water loss and prevent environmental pollution. The drift eliminators can be either cellular or blade type. Cellular type drift eliminators consist of corrugated sheets that form channels for the air to pass through, while blade type drift eliminators consist of flat or curved blades that deflect the air flow.



  • Nozzles: The nozzles are devices that distribute the water evenly over the fill. The nozzles can be either fixed or rotating. Fixed nozzles are attached to a pipe or a header and spray water in a fixed pattern. Rotating nozzles are mounted on arms that rotate by the water pressure and spray water in a circular pattern.



  • Fans: The fans are devices that provide or enhance air flow through the tower. The fans can be either axial or centrifugal. Axial fans have blades that are parallel to the fan axis and move air along the fan axis. Centrifugal fans have blades that are perpendicular to the fan axis and move air radially from the fan axis.



The construction materials of a cooling tower should be selected based on factors such as corrosion resistance, durability, cost and availability. Some of the common materials used for cooling tower construction are:



  • Concrete: Concrete is a strong and durable material that can withstand high temperatures and pressures. Concrete is used for natural draft cooling towers and for some mechanical draft cooling towers.



  • Steel: Steel is a strong and versatile material that can be fabricated into various shapes and sizes. Steel is used for mechanical draft cooling towers and for some components such as fans, nozzles, etc.



  • Fiberglass: Fiberglass is a lightweight and corrosion-resistant material that can be molded into various shapes and sizes. Fiberglass is used for some mechanical draft cooling towers and for some components such as fill, drift eliminators, etc.



  • Wood: Wood is a natural and renewable material that has good thermal properties and low cost. Wood is used for some mechanical draft cooling towers and for some components such as fill, drift eliminators, etc.



Cooling tower performance and efficiency




Cooling tower performance and efficiency are measures of how well a cooling tower rejects heat from the water to the air. Cooling tower performance is usually expressed by two parameters: range and approach.


Cooling tower sizing and selection




Cooling tower sizing and selection is the process of determining the optimal cooling tower model and capacity for a given heat rejection duty and design conditions. Cooling tower sizing and selection involves the following steps:



  • Calculate the design heat load using the formula: Heat Load (BTU/Hr) = GPM X 500 X Range of cooling.



  • Select the design wet bulb temperature based on the location and season of operation.



  • Refer to the cooling tower manufacturer's catalog or website and find the cooling tower model that can handle the design heat load at the design wet bulb temperature.



  • Check the cooling tower performance curve and verify that the selected cooling tower can achieve the desired range and approach at the design conditions.



  • Consider other factors such as space availability, noise level, energy consumption, maintenance requirements, etc., and adjust the cooling tower selection if needed.



For example, suppose you need to select a cooling tower for a process that requires 800 gpm of water to be cooled from 98F to 83F at a design wet bulb temperature of 76F. The steps are as follows:



  • Calculate the design heat load using the formula: Heat Load (BTU/Hr) = GPM X 500 X Range of cooling. Heat Load (BTU/Hr) = 800 X 500 X (98 - 83) = 6,000,000 BTU/Hr



  • Select the design wet bulb temperature of 76F based on the location and season of operation.



  • Refer to the cooling tower manufacturer's catalog or website and find the cooling tower model that can handle 6,000,000 BTU/Hr at 76F wet bulb temperature. For example, according to Delta's catalog, a TM Series induced draft counterflow cooling tower model TM-150-2 can handle 6,250,000 BTU/Hr at 76F wet bulb temperature.



  • Check the cooling tower performance curve and verify that the selected cooling tower can achieve the desired range and approach at the design conditions. For example, according to Delta's catalog, a TM Series induced draft counterflow cooling tower model TM-150-2 can achieve a range of 15F and an approach of 7F at 800 gpm and 76F wet bulb temperature.



  • Consider other factors such as space availability, noise level, energy consumption, maintenance requirements, etc., and adjust the cooling tower selection if needed. For example, if space is limited, you may consider a smaller cooling tower model with a higher fan power consumption. If noise is a concern, you may consider a low-noise fan option or a sound attenuation package.



Cooling tower operation