Technology & Engineering
Heat Exchanger
A heat exchanger is a device used to transfer heat between two or more fluids that are at different temperatures. It works by allowing the fluids to come into thermal contact without mixing. Heat exchangers are widely used in various industrial and domestic applications, such as in HVAC systems, refrigeration, and power plants, to efficiently manage heat transfer processes.
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eBook - PDFHeat Exchangers
Design and Sizing Algorithms
- Abdelhanine Benallou(Author)
- 2024(Publication Date)
- Wiley-ISTE(Publisher)
1 Available Technologies 1.1. Introduction A Heat Exchanger is a device designed to transfer energy from one fluid to another, without any mixing between the fluids. When these energy transfers occur without any phase change, these devices are referred to as Heat Exchangers. When, on the other hand, heat transfer is accompanied by a phase change (liquid to vapor or vice versa), they are known as evaporators, reboilers or condensers, as appropriate. Heat Exchangers are frequently used in industry to heat or cool gases, liquids and even solids. In the automotive industry, Heat Exchangers are used for engine cooling; in this case, we refer to radiators. However, in the embedded electronics field, we know them as heat sinks, which are essential for cooling power components in circuit boards. This diversity in designations also covers a diversity of technologies and above all a variety of calculation methods. As a result, several heat-exchanger design and production technologies exist. The purpose of Chapter 1 is to present the different technologies available on the market and to identify the parameters used to define each type of device and the corresponding fields of use. 1.2. The simplest form of Heat Exchanger: single-tube or coaxial The simplest device is the single-tube Heat Exchanger, consisting of two coaxial tubes: one of the fluids circulates in the central tube, and the second fluid circulates in the annulus between the two coaxial tubes. Figure 1.1 shows a laboratory embodiment where the outer tube (the sleeve or shell) is made of glass, enabling the inner tube to be viewed. In practice, however, the two concentric tubes are metallic (usually made of steel or copper). 2 Heat Exchangers Figure 1.1. “Single-tube” exchanger 1 . For a color version of this figure, see www.iste.co.uk/benallou/energy6.zip This exchanger belongs to the category of tubular Heat Exchangers also known as “shell-tube Heat Exchangers”.
eBook - PDFHeat Exchangers
Selection, Rating, and Thermal Design, Fourth Edition
- Sadik Kakaç, Hongtan Liu, Anchasa Pramuanjaroenkij(Authors)
- 2020(Publication Date)
- CRC Press(Publisher)
1 1 Classification of Heat Exchangers 1.1 Introduction Heat Exchangers are devices that provide transfer of thermal energy between two or more fluids at different temperatures. Heat Exchangers are used in a wide variety of applications such as power generations, chemical processes, food industries, electronics, environmen- tal engineering, waste heat recovery, manufacturing industry, air-conditioning, refrigera- tion, and space applications. Heat Exchangers may be classified according to the following main criteria 1,2 : 1. Recuperators/regenerators 2. Transfer processes: direct contact and indirect contact 3. Geometry of construction: tubes, plates, and extended surfaces 4. Heat transfer mechanisms: single phase and two phase 5. Flow arrangements: parallel flows, counterflows, and crossflows. The preceding five criteria are illustrated in Figure 1.1. 1 1.2 Recuperation and Regeneration The conventional Heat Exchanger, shown diagrammatically in Figure 1.1a with heat transfer between two fluids, is called a recuperator because the hot stream A recovers (recuperates) some of the heat from the cooler stream B. The heat transfer occurs through a separating wall or through the interface between the streams as in the case of the direct-contact-type Heat Exchangers (Figure 1.1c). Some examples of the recuperative type of exchangers are shown in Figure 1.2. In regenerators or storage-type Heat Exchangers, the same flow passage (matrix) is alter- nately occupied by one of the two fluids. When the hot fluid flows through the passage, thermal energy is stored in the matrix; during the cold fluid flow through the same pas- sage at a later time, stored energy is extracted from the matrix. Therefore, thermal energy is not transferred through the wall as in a direct-transfer Heat Exchanger (recuperator). This cyclic principle is illustrated in Figure 1.1b.
No longer available |Learn more- (Author)
- 2014(Publication Date)
- Academic Studio(Publisher)
________________________ WORLD TECHNOLOGIES ________________________ Chapter 12 Heat Exchanger An interchangeable plate Heat Exchanger ________________________ WORLD TECHNOLOGIES ________________________ Tubular Heat Exchanger. A Heat Exchanger is a piece of equipment built for efficient heat transfer from one medium to another. The media may be separated by a solid wall, so that they never mix, or they may be in direct contact. They are widely used in space heating, refrigeration, air conditioning, power plants, chemical plants, petrochemical plants, petroleum refineries, natural gas processing, and sewage treatment. One common example of a Heat Exchanger is the radiator in a car, in which the heat source, being a hot engine-cooling fluid, water, transfers heat to air flowing through the radiator (i.e. the heat transfer medium). Flow arrangement Countercurrent (A) and parallel (B) flows ________________________ WORLD TECHNOLOGIES ________________________ Fig. 1: Shell and tube Heat Exchanger, single pass (1-1 parallel flow) ________________________ WORLD TECHNOLOGIES ________________________ Fig. 2: Shell and tube Heat Exchanger, 2-pass tube side (1-2 crossflow) ________________________ WORLD TECHNOLOGIES ________________________ Fig. 3: Shell and tube Heat Exchanger, 2-pass shell side, 2-pass tube side (2-2 coun-tercurrent) There are two primary classifications of Heat Exchangers according to their flow arrangement. In parallel-flow Heat Exchangers, the two fluids enter the exchanger at the same end, and travel in parallel to one another to the other side. In counter-flow Heat Exchangers the fluids enter the exchanger from opposite ends. The counter current design is most efficient, in that it can transfer the most heat from the heat (transfer) medium. For efficiency, Heat Exchangers are designed to maximize the surface area of the wall between the two fluids, while minimizing resistance to fluid flow through the exchanger.
- Greg F. Naterer(Author)
- 2002(Publication Date)
- CRC Press(Publisher)
10 Heat Exchangers 10.1 Introduction Heat Exchangers are engineering devices that transfer thermal energy between fluid streams at different temperatures. They arise in many applications, including power generation, energy storage, air conditioning systems, materials processing, and various others. Commonly encountered Heat Exchanger configurations include concentric tube , cross-flow , and shell-and-tube Heat Exchangers. In this chapter, the design and analysis of these types of Heat Exchangers will be investigated. Both single phase and multiphase systems will be considered. A concentric tube Heat Exchanger consists of two fluid streams, whereby an internal fluid flows through the inner tube and an external flow passes through the annular region between the inner and outer tubes. If the outer fluid flows in the same direction as the inner flow, then the configuration is called a parallel flow , and if the outer fluid flows in a direction opposite to the inner flow, then it is called a counterflow (see Figure 10.1). Empirical and numerical techniques are usually required for the detailed analysis of these Heat Exchangers. In some cases, semianalytic techniques can be used to determine the thermal effectiveness of heat exchange devices. For example, integral methods described in Chapter 3 can be applied for predictions of heat exchange in gas-fired water heaters (Naterer et al., 1996). The second type of Heat Exchanger (cross-flow) typically consists of an outer flow passing across tubes carrying fluid that flows in a direction perpendicular to the cross-flow. In many cases, the tubes are covered with fins or other annular attachments to enhance the rate of heat transfer between the different fluid streams. If the cross-flow streams are separated from one another (i.e., fins separating fluid streams), then the configuration is unmixed , whereas a mixed configuration permits complete mixing of the fluid streams in the external cross-flow (see Figure 10.1).
No longer available |Learn more- (Author)
- 2014(Publication Date)
- Research World(Publisher)
________________________ WORLD TECHNOLOGIES ________________________ Chapter 4 Heat Exchanger An interchangeable plate Heat Exchanger ________________________ WORLD TECHNOLOGIES ________________________ Tubular Heat Exchanger. A Heat Exchanger is a piece of equipment built for efficient heat transfer from one medium to another. The media may be separated by a solid wall, so that they never mix, or they may be in direct contact. They are widely used in space heating, refrigeration, air conditioning, power plants, chemical plants, petrochemical plants, petroleum refineries, natural gas processing, and sewage treatment. One common example of a Heat Exchanger is the radiator in a car, in which the heat source, being a hot engine-cooling fluid, water, transfers heat to air flowing through the radiator (i.e. the heat transfer medium). Flow arrangement Countercurrent (A) and parallel (B) flows ________________________ WORLD TECHNOLOGIES ________________________ Fig. 1: Shell and tube Heat Exchanger, single pass (1-1 parallel flow) ________________________ WORLD TECHNOLOGIES ________________________ Fig. 2: Shell and tube Heat Exchanger, 2-pass tube side (1-2 crossflow) ________________________ WORLD TECHNOLOGIES ________________________ Fig. 3: Shell and tube Heat Exchanger, 2-pass shell side, 2-pass tube side (2-2 coun-tercurrent) There are two primary classifications of Heat Exchangers according to their flow arrangement. In parallel-flow Heat Exchangers, the two fluids enter the exchanger at the same end, and travel in parallel to one another to the other side. In counter-flow Heat Exchangers the fluids enter the exchanger from opposite ends. The counter current design is most efficient, in that it can transfer the most heat from the heat (transfer) medium. For efficiency, Heat Exchangers are designed to maximize the surface area of the wall between the two fluids, while minimizing resistance to fluid flow through the exchanger.
No longer available |Learn more- (Author)
- 2014(Publication Date)
- Research World(Publisher)
________________________ WORLD TECHNOLOGIES ________________________ Chapter 1 Heat Exchanger An interchangeable plate Heat Exchanger ________________________ WORLD TECHNOLOGIES ________________________ Tubular Heat Exchanger. A Heat Exchanger is a piece of equipment built for efficient heat transfer from one medium to another. The media may be separated by a solid wall, so that they never mix, or they may be in direct contact. They are widely used in space heating, refrigeration, air conditioning, power plants, chemical plants, petrochemical plants, petroleum refineries, natural gas processing, and sewage treatment. One common example of a Heat Exchanger is the radiator in a car, in which the heat source, being a hot engine-cooling fluid, water, transfers heat to air flowing through the radiator (i.e. the heat transfer medium). ________________________ WORLD TECHNOLOGIES ________________________ Flow arrangement Countercurrent (A) and parallel (B) flows ________________________ WORLD TECHNOLOGIES ________________________ Fig. 1: Shell and tube Heat Exchanger, single pass (1-1 parallel flow) ________________________ WORLD TECHNOLOGIES ________________________ Fig. 2: Shell and tube Heat Exchanger, 2-pass tube side (1-2 crossflow) ________________________ WORLD TECHNOLOGIES ________________________ Fig. 3: Shell and tube Heat Exchanger, 2-pass shell side, 2-pass tube side (2-2 counte-rcurrent) There are two primary classifications of Heat Exchangers according to their flow arrangement. In parallel-flow Heat Exchangers, the two fluids enter the exchanger at the same end, and travel in parallel to one another to the other side. In counter-flow Heat Exchangers the fluids enter the exchanger from opposite ends. The counter current design is most efficient, in that it can transfer the most heat from the heat (transfer) medium.
No longer available |Learn more- (Author)
- 2014(Publication Date)
- Academic Studio(Publisher)
________________________ WORLD TECHNOLOGIES ________________________ Chapter 2 Heat Exchanger An interchangeable plate Heat Exchanger ________________________ WORLD TECHNOLOGIES ________________________ Tubular Heat Exchanger. A Heat Exchanger is a piece of equipment built for efficient heat transfer from one medium to another. The media may be separated by a solid wall, so that they never mix, or they may be in direct contact. They are widely used in space heating, refrigeration, air conditioning, power plants, chemical plants, petrochemical plants, petroleum refineries, natural gas processing, and sewage treatment. One common example of a Heat Exchanger is the radiator in a car, in which the heat source, being a hot engine-cooling fluid, water, transfers heat to air flowing through the radiator (i.e. the heat transfer medium). ________________________ WORLD TECHNOLOGIES ________________________ Flow arrangement Countercurrent (A) and parallel (B) flows ________________________ WORLD TECHNOLOGIES ________________________ Fig. 1: Shell and tube Heat Exchanger, single pass (1-1 parallel flow) ________________________ WORLD TECHNOLOGIES ________________________ Fig. 2: Shell and tube Heat Exchanger, 2-pass tube side (1-2 crossflow) ________________________ WORLD TECHNOLOGIES ________________________ Fig. 3: Shell and tube Heat Exchanger, 2-pass shell side, 2-pass tube side (2-2 counter-current) There are two primary classifications of Heat Exchangers according to their flow arrangement. In parallel-flow Heat Exchangers, the two fluids enter the exchanger at the same end, and travel in parallel to one another to the other side. In counter-flow Heat Exchangers the fluids enter the exchanger from opposite ends. The counter current design is most efficient, in that it can transfer the most heat from the heat (transfer) medium. In a cross-flow Heat Exchanger, the fluids travel roughly perpendicular to one another through the exchanger.
No longer available |Learn more- (Author)
- 2014(Publication Date)
- White Word Publications(Publisher)
____________________ WORLD TECHNOLOGIES ____________________ Chapter 2 Heat Exchanger An interchangeable plate Heat Exchanger ____________________ WORLD TECHNOLOGIES ____________________ Tubular Heat Exchanger. A Heat Exchanger is a piece of equipment built for efficient heat transfer from one medium to another. The media may be separated by a solid wall, so that they never mix, or they may be in direct contact. They are widely used in space heating, refrigeration, air conditioning, power plants, chemical plants, petrochemical plants, petroleum refineries, natural gas processing, and sewage treatment. One common example of a Heat Exchanger is the radiator in a car, in which the heat source, being a hot engine-cooling fluid, water, transfers heat to air flowing through the radiator (i.e. the heat transfer medium). ____________________ WORLD TECHNOLOGIES ____________________ Flow arrangement Countercurrent (A) and parallel (B) flows ____________________ WORLD TECHNOLOGIES ____________________ Fig. 1: Shell and tube Heat Exchanger, single pass (1-1 parallel flow) ____________________ WORLD TECHNOLOGIES ____________________ Fig. 2: Shell and tube Heat Exchanger, 2-pass tube side (1-2 crossflow) ____________________ WORLD TECHNOLOGIES ____________________ Fig. 3: Shell and tube Heat Exchanger, 2-pass shell side, 2-pass tube side (2-2 countercurrent) There are two primary classifications of Heat Exchangers according to their flow arrangement. In parallel-flow Heat Exchangers, the two fluids enter the exchanger at the same end, and travel in parallel to one another to the other side. In counter-flow Heat Exchangers the fluids enter the exchanger from opposite ends. The counter current design is most efficient, in that it can transfer the most heat from the heat (transfer) medium. In a cross-flow Heat Exchanger, the fluids travel roughly perpendicular to one another through the exchanger.
No longer available |Learn more- (Author)
- 2014(Publication Date)
- Orange Apple(Publisher)
________________________ WORLD TECHNOLOGIES ________________________ Chapter 10 Heat Exchanger An interchangeable plate Heat Exchanger ________________________ WORLD TECHNOLOGIES ________________________ Tubular Heat Exchanger. A Heat Exchanger is a piece of equipment built for efficient heat transfer from one medium to another. The media may be separated by a solid wall, so that they never mix, or they may be in direct contact. They are widely used in space heating, refrigeration, air conditioning, power plants, chemical plants, petrochemical plants, petroleum refineries, natural gas processing, and sewage treatment. One common example of a Heat Exchanger is the radiator in a car, in which the heat source, being a hot engine-cooling fluid, water, transfers heat to air flowing through the radiator (i.e. the heat transfer medium). ________________________ WORLD TECHNOLOGIES ________________________ Flow arrangement Countercurrent (A) and parallel (B) flows ________________________ WORLD TECHNOLOGIES ________________________ Fig. 1: Shell and tube Heat Exchanger, single pass (1-1 parallel flow) ________________________ WORLD TECHNOLOGIES ________________________ Fig. 2: Shell and tube Heat Exchanger, 2-pass tube side (1-2 crossflow) ________________________ WORLD TECHNOLOGIES ________________________ Fig. 3: Shell and tube Heat Exchanger, 2-pass shell side, 2-pass tube side (2-2 countercurrent) There are two primary classifications of Heat Exchangers according to their flow arrangement. In parallel-flow Heat Exchangers, the two fluids enter the exchanger at the same end, and travel in parallel to one another to the other side. In counter-flow Heat Exchangers the fluids enter the exchanger from opposite ends. The counter current design is most efficient, in that it can transfer the most heat from the heat (transfer) medium.
eBook - PDF- Stephen Whitaker(Author)
- 2013(Publication Date)
- Pergamon(Publisher)
11 Design of Heat Exchangers In the previous ten chapters we encountered various aspects of heat transfer design. In Design Problem I we considered the use of insulation to reduce heat losses, and in Probs. II and IV we explored the problem of insulating a heated vessel so that the outer surface would be safe to touch. Problem III dealt with the use of hot water to heat apartments, while in Prob. V we were again concerned with reducing heat losses from homes and office buildings. Problem VI dealt with the design of a thermal mixing system which was used to dispose of excess heat, and Prob. VII was our first introduction to the design of a Heat Exchanger. Clearly there is a wide range of heat transfer design problems that an engineer might encounter, but one of the most important processes to be considered is simply the exchange of heat between two process streams. A great deal of research, some of which we encountered in Sees. 7.6-7.9, has been devoted to this subject, and books [1,2] are available which treat only the subject of Heat Exchanger design. In our treatment we will cover the main points concerning the thermal design of Heat Exchangers while leaving the equally important mechanical design for further study by the interested student. Although the double-pipe Heat Exchanger has been discussed in Prob. VII, we will begin our analysis of Heat Exchangers with a thorough treatment of the double-pipe Heat Exchanger. 11.1 The Double-Pipe Heat Exchanger One of the simplest means of transferring heat between two process streams ; s the double-pipe Heat Exchanger shown in Fig. 11.1.1. The configuration shown is for co-current flow ; however, counter-current flows are usually used since they require less heat transfer surface to accomplish the same total heat transfer rate. Throughout this chapter we will use the subscripts i and o to designate the inlet and outlet temperature respectively.
eBook - PDF- Nicholas P Cheremisinoff(Author)
- 2000(Publication Date)
- Butterworth-Heinemann(Publisher)
HEAT EXCHANGE EQUIPMENT 11 Another area to consider is Heat Exchanger efficiency. The concept of efficiency is to compare the actual performance of a piece of equipment with the ideal performance (i.e., the maximum potential heat transfer). The maximum heat transfer possible is established by the stream that has the minimum heat capacity. That is the minimum value for the product of stream mass flowrate and specific heat. This stream would, for maximum heat transfer, leave the exchanger at the inlet temperature of the other stream. In terms of the hot stream, the efficiency can be stated as: e = Cp,hmh(th,in- th,out)/((Cpm)min(th,in - tc,in)) And, in terms of the cold stream: e = Cp,cmc(tc,in - tc,out)/((Cpm)min (th,in - tc,in)) In the above expressions: e = Heat Exchanger efficiency, th,in = the inlet temperature of the hot stream (~ tc,ou t = the outlet temperature of the cold stream (~ th,ou t = the outlet temperature of the hot stream (~ tc,in = the inlet temperature of the cold stream (~ Cp,hm = the product of the hot stream heat capacity and the mass flowrate, Cp,cm = the product of the cold stream heat capacity and the mass flowrate, (Cpm)min = the minimum product of stream heat capacity and mass flowrate. Knowing the efficiency, one can use this value to predict Heat Exchanger performance for other streams and fluids. Efficiency is based on the maximum amount of heat that can be transferred: q - e(Cpm)min (th,in- tc,in) 12 HANDBOOK OF CHEMICAL PROCESSING EQUIPMENT AIR COOLED Heat ExchangerS Air cooled Heat Exchangers are used to transfer heat from a process fluid to ambient air. The process fluid is contained within heat conducting tubes. Atmospheric air, which serves as the coolant, is caused to flow perpendicularly across the tubes in order to remove heat. In a typical air cooled Heat Exchanger, the ambient air is either forced or induced by a fan or fans to flow vertically across a horizontal section of tubes.
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