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Estimating Cooling Tower Blowdown Flowrate
Guide to Compact Heat Exchangers [PDF]
Effectively Design Shell-and-Tube Heat Exchangers (PDF)

Chemical Engineering Progress

<<This article explains the basics of exchanger thermal design, covering such topics as: STHE components; classification of STHEs according to construction and according to service; data needed for thermal design; tubeside design; shellside design, including tube layout, baffling, and shellside pressure drop; and mean temperature difference. >>

Selecting TEMA Type Heat Exchangers

<< This article defines TEMA constructions and identifies the advantages and limitations for each type. TEMA designations refer to the front-head, shell and rear-head designs. For example, a TEMA type BEM has a type B front head, a type E shell and a type M rear head design. There are special conditions such as high vapor flows, high pressure and temperature crossing where a combination of TEMA features is advantageous. For example, K type shells allow for proper liquid disengagement for reboilers, and J and H type shells accommodate high vapor flow. >>

Shell And Tube Heat Exchangers

ITT Standard

<< Overview of various types of shell and tube heat exchangers. >>

5 Steps to Prevent Fluid Freezing

<<Heat transfer fluids remove and carry thermal energy from one location to another. In a cooling process, the fluid removes heat from the user's process while being pumped through a cooling source, where it gives up thermal energy. Heat transfer fluids play an important role in many cooling applications, including chemical, pharmaceutical, freeze-drying, food and beverage processing and climactic chambers. Petroleum-based natural and synthetic hydrocarbons, silicone oils, aqueous brines and glycols are popular low temperature fluids for those uses. >>

Benefits of Brazed-Plate Heat Exchangers

FlatPlate, Inc.

<<Over the past decade a new technology has been taking hold on the US market. It offers significant advantages over the standard shell and tube heat exchanger, and it is flexible so it can be used in a variety of applications. Known as Plate Heat Exchangers, these units are significantly smaller in size, and are a more efficient option than their counterparts. Overall efficiency goes beyond the ability to transfer BTU's. Plate Heat Exchanger technology is not new, having been around for about 60 years. European companies have successfully used Plate Heat Exchangers in many different applications. There the technology has been refined, and the results are such now that many US industries are taking a new fresh look. >>

Basics of Air-Cooled Heat Exchangers

Hudson Products Corporation

<<An ACHE is a device for rejecting heat from a fluid directly to ambient air. This is in contrast to rejecting heat to water and then rejecting it to air, as with a shell and tube heat exchanger and a wet cooling tower system.>>

What is a Cooling Tower?

Cooling Technology Institute

<<Common applications for cooling towers are providing cooled water for air-conditioning, manufacturing and electric power generation. The smallest cooling towers are designed to handle water streams of only a few gallons of water per minute supplied in small pipes like those might see in a residence, while the largest cool hundreds of thousands of gallons per minute supplied in pipes as much as 15 feet (about 5 meters) in diameter on a large power plant.>>

Operating Cooling Towers in Freezing Weather

Marley Cooling Technologies, Inc

<<As on any outside structure, ice can form on a cooling tower in the wintertime purely by natural effect. In addition, being both a water cooling and an air moving device, a cooling tower can promote the formation of ice by its very operation.>>

External Influences on Cooling Tower Performance

Marley Cooling Technologies, Inc

<<Why then do a significant number of cooling towers appear to be performing inadequately in spite of this dedication by both the user and the manufacturer? In many cases, the problem can be traced to environmental factors which affect the quantitiy and/or thermal quality of the air entering the tower. This report will describe situations contributing to a poor air supply, and will suggest the preplanning necessary to ameliorate those situations.>>

Controlling Steam Heaters

Walter Driedger

<<Steam Heaters are simply heat exchangers in which one of the media is steam being condensed while the other is a process fluid being heated. In doing this, there is a phase change which puts special demands on the process control system. It is difficult to generalize about the various options for control. Special system requirements often put unexpected constraints on the process. Even the orientation of the exchanger can have peculiar and unexpected results.>>

Controlling Fired Heaters

Walter Driedger

<<The purpose of a fired heater is very simple: To add heat to a process fluid. Its representation on a process flow diagram is also very simple. But, of course, fired heaters are among the most complex pieces of process control equipment. Each furnace is, after all, at least two pieces of equipment in one. Firstly, it is a special variant of the shell and tube heat exchanger since its purpose is to exchange heat. Secondly, it is a chemical reactor in which fuel and air undergo extremely exothermic reactions to produce the required heat.>>

Cleaning and Passivation of New Cooling Towers

CSC Technology

<<Prior to hydraulic testing or putting a new system into service, it must be cleaned to remove oil, grease, new pipe mill scale, silts and organic debris, and general rust accumulations. It is then chemically passivated to inhibit corrosion of the various metallurgies involved. Since the system may also contain microbiological contamination, disinfection should be provided prior to allowing any aerosol emissions from any wet-type heat rejection device (WTHRD), eg cooling towers, evaporative condensers, etc. Accordingly, the cleaning and disinfection procedures presented herein also incorporate the procedural concepts and disinfection guidelines for system start-up as endorsed by The Centers for Disease Control and Prevention (CDC) and as published in the "1987 Wisconsin Guidelines" entitled, Control of Legionella in Cooling Towers, Summary Guidelines.>>

Introduction To Fired Heater Design

<<This introduction to Fired Heater Design is presented to provide an overview of the considerations and methods used in the thermal and mechanical design of furnaces and fired heaters for the Refining & Petrochemical Industry.>>

Heat Exchangers Design


<<Simple and effective thermal design and rating of heat exchangers. Prode HED provides a simple and effective way for the thermal design and rating of shell and tube heat exchangers, Prode HED analyses all the common heat exchangers processes : Sensible heat, both liquid and vapor, Forced circulation evaporators, Horizontal and vertical condensers, Falling film evaporators.>>

Heat Exchangers Installation Operation and Maintenance Manual

ITT Standard

A Baffle by Any Other Name...

<<Confused about heat exchanger terms, or just looking for a good primer on the topic? Consult this glossary of terms.>>

Design and Specification of Air-Cooled Steam Condensers (PDF Document)

Hudson Products Corporation

<<Steam turbines are finding increasing use in electric-utility powerplants, industrial plants, process plants and commercial installations. Such turbines drive not only electric generators but also all types of pumps, fans, compressors, shredders, mills, paper machines, and so on. Steam condensers coupled to the exhaust of these turbines return condensate to the power cycle and boiler. Either surface-type or air-cooled condensers can be selected. The former have once-through or recirculating water as the cooling medium, while the latter are once-through systems employing the atmosphere as the heat sink. Among the advantages of air-cooled steam condensers, compared with wet systems, are elimination of: makeup water supply, blowdown disposal, water-freezing problems, water vapor plumes, and concerns over governmental water-pollution restrictions. Because of the dry nature of the equipment, lower system-maintenance costs also result.>>

Index of Cooling Tower Thermal Design

Daeil Aqua Co., Ltd

<<Psychrometrics, Heat & Mass Transfer Fundamentals, Tower Demand & Characteristic Curves, Cooling Tower Performance Variables, Consideration of By-pass Wall Water, Pressure Drops in Cooling Tower, Velocity Recovery at Fan Stack, Motor Power Sizing, Fan Components Sizing, Air-Water Distribution System Design, Recirculation of Exit Air, Evaporation, Estimation of Actual Cold Water Temperature, Determination of L/G, Compare of Tower Performance at Sea Level and Altitude, Evaluation of Tower Performance at Design Off Design, Plotting of Tower Performance Curves, Estimation of Air Flow at No-Load Condition, Determination of Pumping Head, Determination of Line Voltage Drop, Calculation of Tower Capability by Tower Characteristic Curve, Calculation of Tower Capability by Tower Performance Curve.>>

Air-Cooled Heat Exchangers

Stone Process Equipment Co.

<<Air-cooled heat exchangers are generally used where a process system generates heat which must be removed, but for which there is no local use. A good example is the radiator in your car. The engine components must be cooled to keep them from overheating due to friction and the combustion process. The excess heat is carried away by the water/glycol coolant mixture. A small amount of the excess heat may be used by the car's radiator to heat the interior. Most of the heat must be dissipated somehow. One of the simplest ways is to use the ambient air. Air-cooled heat exchangers (often simply called air-coolers) do not require any cooling water from a cooling tower. They are usually used when the outlet temperature is more than about 20 deg. F above the maximum expected ambient air temperature. They can be used with closer approach temperatures, but often become expensive compared to a combination of a cooling tower and a water-cooled exchanger. >>

Exchanger Nozzle Location Identifier Sheet

API Heat Transfer

<<Link automatically launches Adobe Acrobat Reader if installed on your computer.>>

Basic Construction of Shell and Tube Heat Exchangers

API Heat Transfer

<<Link automatically launches Adobe Acrobat Reader if installed on your computer. Large document.>>

Fundamentals of Cooling Tower Design & Optimization

<<Your cooling tower may be the most overlooked piece of equipment at your facility. A cooling tower uses a combination of heat and mass transfer to cool process water. If improperly selected or poorly maintained, it will cost you financially, causing a loss in production due to increases in circulation water temperature and increased electrical operating costs. Emphasis must be placed on properly specified and designed cooling towers that require minimal maintenance. Cooling towers come in all shapes and sizes. Cooling towers with fans are referred to as mechanical draft forced or induced draft, depending on fan location. Some cooling towers, used primarily in the utility industry, operate on a natural draft chimney principle without any fans. As their name implies, cooling towers employing this design are referred to as natural draft. >>

Heat Exchanger Design Q & A

<<Heat exchanger manufacturers need answers to a number of questions to correctly size a heat exchanger for a specific application. The questions attempt to address the three basic points that drive heat exchanger design: Why a heat exchanger is needed, what the exchanger needs to do, how the exchanger can do the job. >>

Selecting a Heat Transfer Fluid

<<Process engineers have a number of secondary coolants from which to choose. A nontoxic fluid with good thermophysical properties and a long service life usually is your best choice. Low temperature heat transfer fluids are crucial components in many process applications. Current heat transfer fluid technologies include direct refrigerant use as well as liquefied gas and secondary refrigeration technology using various low temperature fluids. In a secondary refrigeration process, a primary refrigerant or a liquefied gas is used to cool the heat transfer fluid. The cold heat transfer fluid then is circulated through the user’s process to provide uniform temperature distribution. This secondary refrigeration process uses smaller refrigerant amounts to cool the heat transfer fluid. In general, the secondary refrigeration approach has several advantages.>>

Expanding the Use Of Ammonia

ASHRAE Journal Online

<<Ammonia has excellent thermodynamic properties, but part of this potential will be lost if the heat exchangers have a low efficiency. The liquid chillers using HCFCs or HFCs have shell-and-tube heat exchangers using high-efficiency copper tubes, with sophisticated enhanced surfaces. Spectacular improvements have been achieved with this technology in the past decade. However, copper is not compatible with ammonia, and the traditional carbon steel shell-and-tube ammonia heat exchangers tend to be significantly larger than those used with other refrigerants. They also have a large refrigerant charge, which is not desired with ammonia for safety reasons. For new applications, this excludes the use of the traditional flooded evaporators or pump-fed in-tube recirculation systems. On the other hand, shell-and-tube D-X evaporators could not be used until recently because miscible oils were not available. This is why new solutions had to be found, implementing new combinations of materials, exchanger technologies (e.g., plate heat exchangers, or high efficiency tubes), new miscible oils, and expansion devices.>>

Controlling Shell and Tube Heat Exchangers

Walter Driedger

<<Shell and tube heat exchangers are among the more confusing pieces of equipment for the process control engineer. The principle of operation is simple enough: Two fluids of different temperatures are brought into close contact but are prevented from mixing by a physical barrier. The temperature of the two fluids will tend to equalize. By arranging counter-current flow it is possible for the temperature at the outlet of each fluid to approach the temperature at the inlet of the other. The heat contents are simply exchanged from one fluid to the other and vice versa. No energy is added or removed. Since the heat demands of the process are not constant, and the heat content of the two fluids is not constant either, the heat exchanger must be designed for the worst case and must be controlled to make it operate at the particular rate required by the process at every moment in time. The heat exchanger itself is not constant. Its characteristic changes with time. The most common change is a reduction in the heat transfer rate due to fouling of the surfaces. Exchangers are initially oversized to allow for the fouling which gradually builds up during use until the exchanger is no longer capable of performing its duty. Once it has been cleaned it is again oversized. >>

Plate and Frame Heat Exchangers

Paul Mueller Company

<<Plate and frame heat exchangers, commonly known as "plate" heat exchangers, originated over 60 years ago in the European food industry. There was a need for a heat transfer device that was energy efficient, compact, easy to clean, and capable of being modified as design conditions changed. These original requirements were met with a plate and frame heat exchanger. Today the same fundamental needs exist and plate heat exchangers are used worldwide in most industries.>>

Anatomy of a Clean Water Environment

Cooling Technology, Inc.

<<Water, by it's very nature provides us with an excellent medium in which to exchange and transport heat energy to and from industrial processes. It has the capacity to hold large amounts of heat, flows easily with low resistance, enters turbulent flow dynamics with fairly low fluid velocity, has a very low viscosity, is non-toxic to the environment and is readily available at low cost. However, water also has properties which when left unaddressed can result in system wide contamination which affects its ability to efficiently exchange heat and results in corrosion to equipment, downtime and costly maintenance procedures. The purpose of this report is to examine industrial water system design and identify the thermal and fluid dynamics of water to derive methods to maximize its positive attributes while minimizing its liabilities.>>

No More Fouling: The Spiral Heat Exchanger

<<Heat exchanger fouling is a major source of maintenance costs and lost production time. It has been estimated that fouling costs U.S. industry more than $5 billion annually. Over time, as material builds up on the heat transfer surfaces of a typical heat exchanger, an insulating layer is formed that reduces the heat transfer rate and increases pressure drop through the exchanger. Eventually, the heat exchanger must be cleaned to restore the heat transfer rates and pressure drops required by the process. With many traditional heat exchanger designs, cleaning is time-consuming and costly, and it may need to be performed frequently. A spiral heat exchanger can help processors avoid these problems.>>

Construction Basics of Shell and Tube Heat Exchangers

<<Although there exists a wide range of designs and materials, some components are common to all. In all shell and tube heat exchangers, the tubes are mechanically attached to tube sheets, which are contained inside a shell with ports for inlet and outlet fluid or gas. They are designed to prevent the liquid flowing inside the tubes from mixing with the fluid outside the tubes. Tube sheets can be fixed to the shell or allowed to expand and contract with thermal stresses. In the latter design, an expansion bellows is used or one tube sheet is allowed to float inside the shell. The nonfixed tube sheet approach allows the entire tube bundle assembly to be pulled from the shell to allow cleaning of the shell circuit.>>

Fundamental Discourse on Cooling Towers

Cooling Tower Doctor

Steam Control and Condensate Drainage for Heat Exchangers

ITT Industries

<<Heat transfer units that use steam to produce hot water are known as indirect heaters. They are often shell and tube type heat exchangers and are generally referred to as converters, hot water generators, and instanta-neous heaters. The ASME Code for Unfired Pressure Vessels is the nationally recognized authority prescribing their construction for given temperatures and pressures. The term used varies with the heating medium and the manner of application. When these heaters use steam as the heat source they are usually called steam to water converters. In steam heated converters, the water to be heated circulates through the tubes and steam circulates in the shell surrounding the outside of the tubes. This results in condensate draining to the bottom of the heat exchanger shell as the steam gives up its latent heat.>>

Troubleshooting Steam Heat Exchangers

Fluid Handling University

<<When a heat exchanger "stalls," condensate floods the steam space and causes a variety of problems within the exchanger.>>

Advantages of Brazed Heat Exchangers in the Gas Processing Industry

Bryan Research and Engineering, Inc.

<<Brazed aluminum heat exchangers have superior heat transfer capabilities and can be cost effective for non-corrosive gases and liquids as compared with traditional shell-and-tube exchangers. Even so, brazed aluminum exchangers are often not considered because of complicated design equations and complex stacking arrangements. The simpler yet less efficient shell-and-tube exchangers or networks of shell-and-tubes are employed instead. Recently, the design equations for multistream brazed aluminum heat exchangers for both single and multiphase flow have been added to the Heat Exchanger Rating package of the process simulator PROSIM® . This paper presents guidelines for designing a brazed exchanger, and the brazed exchanger is compared with traditional shell-and-tube exchangers and networks of exchangers in several examples.>>

Marine Applications of Copper-Nickel Alloys

Copper-Nickel Condenser and Heat Exchanger Systems

<<For the vast majority of heat transfer equipment applications, the transfer of heat takes place between two fluid streams. The heat exchanger is simply a device which directs the flow paths in such a way that the two streams are brought into thermal contact through a conducting wall while being kept physically separate. This thermally conductive wall is the tube in shell-and-tube type heat exchangers that make up a large percentage of such units in power plants, ships, the chemical process industry and in desalination. The relatively thin-walled tube, selected primarily for heat transfer efficiency, becomes the critical component in condensers and other heat exchangers and must perform well over long periods of time under sometimes very difficult operating conditions. Copper-nickel alloys have established a long and successful history in seawater cooled heat exchangers and will be emphasized in this paper.>>

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ISSN 1496-3426
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