Once the heat exchanger is divided into segments in the simulation, m represents the heat exchanger mass of one segment. Energy balance calculation is often done for designing a heat exchanger to determine operating parameters for hot and cold fluids such as inlet outlet temperatures and flow rates. A heat exchanger is a system used to transfer heat between two or more fluids. This double action is economically accomplished by a. Counter flow heat exchangers are the most efficient of the three types. For the heat transfer to occur two fluids must be at different temperatures and they must come thermal contact. Regenerative versus nonregenerative heat exchangers. The heat exchanger must fulfil process requirements after fouling. Heat exchanger is a process equipment designed for the effective transfer of heat energy between two fluids. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Combine ficks law with the principle of conservation of mass. Following particle deposition, deposit growth and consolidation or. In the analysis of heat exchangers, it is often convenient to work with an overall heat transfer coefficient, known as a ufactor.
A heat exchanger is an equipment where heat energy is transferred from a hot fluid to a colder fluid. The enhanced heat transfer techniques for compact heat exchangers in various applications. Heat exchangers have a very broad range of industrial applications. Gulley, gulley computer associates, tulsa, oklahoma.
Heat exchangers are crucial in thermal science and engineering because of their essential role across the landscape of technology, from geothermal and fossil power generation to refrigeration, desalination, and air conditioning. It is taken for granted that the media are not mixed together. Q1 2 p dt in order to obtain the solutions, we need to solve the coupled mass, energy and momentum conservation equations. In heat exchanger analysis, it is often convenient to combine. Recent development of generalized correlations, taking theoretical, semiempirical 4 or. Talabot, bp 1, 31106 toulouse cedex 1, france b atomic energy commissiongreth, 17 avenue des martyrs, f38054 grenoble cedex 9, france. Heat exchangers are devices that facilitate the exchange of heat between two fluids that are at. An easytounderstand introduction to how a heat exchanger passes heat. A heat exchanger follows this principle in its endeavour to reach equalisation. Hence, the design of such networks is an important aspect of chemical process design. It is therefore possible to heat or cool fluids or gases which have minimal energy levels. A third type of heat exchanger is a plate and shell heat exchanger, which combines plate heat exchanger with shell and tube heat exchanger technologies. The heat exchangers are classified in different categories and we use different heat exchanger at different application as per our requirement.
In contrast to the parallel flow heat exchanger, the counter flow heat exchanger can have the hottest coldfluid temperature greater than the coldest hotfluid temperatue. Many factors are involved in the selection of heat exchangers like size, structural strength, capacity, weight, pressure drop and cost. The term heat exchanger applies to all equipment used to transfer heat between two streams. Basic design methods of heat exchanger, heat exchangers design, experiment and simulation, s m sohel murshed and manuel matos lopes, intechopen, doi. The ufactor is defined by an expression analogous to newtons law of cooling. The heat exchanger ensures the conservation of heat energy. For example, figure 4 shows a hotfluid stream being cooled by a coldfluid stream in a counterflow heat exchanger. Shah rochester institute of technology, rochester, new york formerly at delphi harrison thermal systems, lockport, new york dus. The exchanger takes one inlet and one outlet for hot fluid stream, and one inlet and one outlet for cold fluid stream. The transfer of heat energy between the two fluids could be carried out. To reduce the temperature of a hot fluid by means of a cooler fluid 3. A heat exchanger is a device used to transfer heat between two or more fluids. Heat exchangers are commonly used in industry, and proper design of a heat exchanger depends on many variables.
Subscripts h and c refer to the hot and cold fluids, respectively, and subscripts i and o refer to the inlet and outlet of the heat exchanger, respectively. Learn more about the working principle of sondex sps heat. When designing or choosing a heat exchanger there is no single correct solution. The general principles of the mechanical design of the following types of exchangers are given in the heat exchanger design handbook 1994, and full descriptions of each, are given under the corresponding entries in this encyclopedia. Energy balance calculation for heat exchanger enggcyclopedia. The optimum heat transfer rate takes place in a balanced counter flow heat exchanger and by using this optimum rate of heat transfer, the concept of heat exchanger efficiency is. The essential principle of a heat exchanger is that it transfers the heat. Direct heat exchanger, where both media are in direct contact with each other. However, mutlistream heat exchangers are sometimes used with energy extensive processes, such as lng processing, to reduce capital cost. The heat transfer module users guide comsol documentation. In many engineering applications it is desirable to increase the temperature of one fluid while cooling another. Other approaches to control fouling control combine the blind application of. In convection heat transfer, the heat is moved through bulk transfer of a nonuniform temperature fluid.
A heat exchanger is a device that is used to transfer thermal energy enthalpy between two or more fluids, between a solid surface and. Each individual heat exchanger in the network can be designed by the methods. The sondex sps plate and shell heat exchanger range combine the strengths. Nearterm schedule m 3 nov heat exchanger design, analysis cody w 5 nov alternative to. Heat exchange involve convection in each fluid and conduction through the separating wall. They are used as components of air conditioning and cooling systems or of heating systems. Merge above and below the pinch designs b evolve the. Heat exchangers are typically employed in the process industries as a means of providing heat transfer between two streams of fluid across a medium. Heat exchangers jordan university of science and technology. These devices can be used widely both in daily life and industrial applications such as steam generators in thermal power plants, distillers in chemical industry, evaporators and condensers in hvac applications and refrigeration process, heat sinks, automobile radiators and regenerators. Heat exchangers are devices that transfer energy between fluids at different temperatures by heat transfer. In addition, we will examine various aspects of heat exchanger design and analysis. If you are reading the documentation as a pdf file on your computer, the blue links do. Heat exchanger, any of several devices that transfer heat from a hot to a cold fluid.
Each tube is thin walled, of diameter d25 mm, and makes eight passes through the shell. T hi t ho t hi t ho t ci t co distance along the exchanger faith a. Unit operations lab heat exchanger 12 theory notes 1. Consolidation of conventional methods of calculation of heat exchangers f factor. Pdf a method to combine local heat transfer and flow. Devices involving energy sources such as nuclear fuel pins or fired heaters are not normally regarded as heat exchangers although many of the principles. Composite heat exchangers combine the best features of their parent. The particular case of this process is heat transfer representing convective heat exchange between a moving medium and its interface with another medium, solid body, liquid or gas. The information presented here along with the books referenced here is certainly a good start.
In the aviation engineering, they have a fundamental role especially in reducing the temperatures of the fuel and thus increasing the efficiency of the. Different types of shell and tube designs are possible. Heat exchangers 73 individual thermal resistances of the system. Heat exchanger effectiveness ntu method if more than one of the inlet and outlet temperature of the heat exchanger is unknown, lmtd may be obtained by trial and errors solution. An exchangers effectiveness is the ratio of the actual heat transferred to the heat that could be transferred by an exchanger of infinite size. Pdf investigation of heat transfer characteristics of a water to. Heat exchangers a heat exchanger is a piece of equipment that continually transfers heat from one medium to another. Ntu approach cody f 7 nov natural convection, boiling kevin. Troubleshooting shellandtube heat exchangers use these techniques and guidelines to ensure more reliable heat transfer d.
Many industrial processes call for a certain degree of heat to function. Another approach introduce the definition of heat exchanger effectiveness, which is a dimensionless with ranging between 0 to1. Typically, a heat exchanger is used with two process streams. The oil provides an average convection coefficient ho 400 wm2k on the outside of the tubes. Effectiveness is the best way to compare different types of heat exchangers. Combining each of these resistances in series gives. The fluids can be single or two phase and, depending on the exchanger type, may be separated or in direct contact. With a plate type heat exchanger, the heat penetrates the surface, which separates the hot medium from the cold one very easily. The second heat transfer process is convection, or heat transfer due to a flowing fluid. Innovative heat exchanger technology enhances proven designs.
In this chapter we will examine the basic theory of heat exchangers and consider many applications. Pdf compact heat exchangers development researchgate. Theory and selection heat exchangers are devices that transfer heat between two luids. The fundamentals of heat exchangers wanderlodge gurus. A heat exchanger follows this principle in its endeavour to reach equalization. The sondex sps heat exchangers offer a small footprint and great thermal performance. Heat exchanger and its types engineering solutions. Experimental and theoretical analysis of the local condensation heat transfer in a plate heat. Heat exchanger design handbook pdf alzaytoonah university.
Heat exchangers study notes for mechanical engineering. In theory, we could get the heat from the gas jets just by throwing cold water onto them, but. Innovations such as twisted tubes, expanded metal baffles, graphenecoated surfaces, and more are improving heat exchanger and condenser performance. A heat exchanger is a component that allows the transfer of heat from one fluid liquid or gas to another fluid. Heat exchanger design to choose a suitable heat exchanger for a certain application requires a level of knowledge and experience. A heat exchanger is a device that allows heat from a fluid a liquid or a gas to pass to a second fluid another liquid or gas without the two fluids having to mix together or come into direct contact.
The shellandtube heat exchanger is composed of a shell containing a large number of tubes. Pdf in recent years, thermal control systems performance has improved in numerous ways due to developments in control theory and information. Pdf heat exchanger is a device that transfers heat from one fluid to another or from or to a fluid and the environment. The transport of energy in chemical plants and petroleum refineries is accomplished by means of heatexchanger networks hens. The heart of the heat exchanger contains a fully welded circular plate pack made by pressing and cutting round plates and welding them together. Project theory section due friday next week cody will teach class monday and wednesday next week, and will give the help session on wednesday. The heat exchanger block is used when two process streams are to exchange heat based on equations 11 14. If possible, the heat exchanger should be designed to be selfcleaning, in other words so that the growth rate of fouling layer will slow down and eventually stop at a certain level. The exterior boundaries of each isothermal domain need the heat exchange to be specified. To heat a cooler fluid by means of a hotter fluid 2. R sekulib university of kentucky introduction a heat exchanger is a device that is used for transfer of thermal energy enthalpy between two or more fluids, between a solid surface and a fluid, or between solid particulates and a.
A heat exchanger is a device that is used to transfer thermal energy enthalpy between two or more fluids, between a solid surface and a fluid, or between solid particulates and a fluid, at different temperatures and in thermal contact. Mechanical engineering, energy systems and sustainable development vol. The heat exchanger theory article provides you with information about the fundamentals of a heat exchanger and will be useful for a heat exchanger inspection concept to describe this theory, you may know we need to heat or to cool process fluids in industrial plants to facilitate process reactions. In a single pass heat exchanger, the fluid goes into one end of a tube and out the other. The tubes can also be straight, with one or two passes. Heat exchanger analysis heat exchanger calculation. Increasing heat exchanger performance flow control network. The heat exchange process in heat exchangers can be done by the. A heat exchanger is a piece of equip ment that continually transfers heat from one medium to another.
680 1562 1040 1079 742 222 899 175 933 448 1272 428 1264 6 673 10 386 1529 549 504 1604 611 1301 1248 708 934 1099 957 1151 1574 1520 164 516 91 235 1498 1391 944 1180 1237