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. Two months ago i faced a design problem regarding a heat exchanger. Heat exchangers jordan university of science and technology. Why do i see distortions in the equations in the ebook. Heat exchanger theory leads to the basic heat exchanger design equation. Basic equations for the design of a plate heat exchanger the methodology employed for the design of a phe is the same as for the design of a tubular heat exchanger.
Heat exchanger calculations and design with excel spreadsheet. Two examples of this are adiabatic wheels, which consist of a large wheel with fine threads rotating through the hot and cold fluids, and fluid heat exchangers. Shell and tube heat exchanger design software for thermal. Most processes require the heating or cooling of streams to produce a desired temperature before the stream can be fed to operations. The information presented here along with the books referenced here is certainly a good start. The heat exchanger layout depends on the heat transfer area hta so an initial estimate is. An example of this type of heat exchanger is a cooling tower, where water is cooled through direct contact with air. A heat exchanger is a device that is used to transfer thermal energy enthalpy between two or more fluids, between a solid surface and. Air to air heat exchanger calculations give the possibility to make the right choice of the product which correspond to your demands. For heat transfer analysis of regenerators, the ntu method of recuperators needs to be modified to take into account the thermal energy storage capacity of the. This equation is quite straight forward based on the geometry of the selected shell and tube heat exchanger. Download the excel spreadsheet templates in this article to make preliminary heat exchanger design calculations. Q is the rate of heat transfer between the two fluids in the heat exchanger in buthr, u is the overall heat transfer coefficient in btuhrft 2 o f, a is the heat transfer surface area in ft 2, and. Gaskets, in addition to their sealing effect, serve to direct the flow of the fluids, and are placed along the grooves at the edges of the plates.
The actual design of heat exchangers is a complicated problem. Since all heat exchangers considered in this experiment have a single pass for both the hot and cold fluids, the discussion below is limited to singlepass heat exchangers. E1mnl032a design and rating of shell and tube heat. The goal of heat exchanger design is to relate the inlet and outlet temperatures, the overall heat transfer coefficient, and the geometry of the heat exchanger, to the. Heat exchangers are devices designed to transfer heat between two or more fluidsi. Shell and tube heat exchanger partial differential equations in the analysis of a heat exchanger, or any heat transfer problem, one must begin with an energy balance. Basic equations for the design of a plate heat exchanger. Heat exchangers are usually analyzed using either the logarithmic mean temperature difference lmtd or the effectiveness number of transfer units. Depending on the type of heat exchanger employed, the heat transferring process can be gastogas, liquidtogas, or liquidtoliquid and.
Thermal design during heat exchanger design often overall heat transfer coefficient is used that connects the rate of heat transfer to the temperature difference of the system. Plate heat exchanger working principle, how a plate heat. Shellandtube heat exchangers can have multiple passes, such as 11, 12, 14, 16, and 18 exchangers, where the first number denotes the number of the shells and the second number denotes the number of passes. Heat exchanger and its types engineering solutions. The basic design equation and overall heat transfer coefficient the basic heat exchanger equations applicable to shell and tube exchangers were developed in chapter 1. The heat exchanger layout depends on the heat transfer area hta so an initial estimate is required based on a trial value of the ohtc. They are widely used in space heating, refrigeration, air conditioning, power stations, chemical plants, petrochemical plants, petroleum. As its name implies, this type of heat exchanger consists of a shell a large vessel. The area density for doublepipe heat exchanger can not be in the order of 700. Heat exchanger gg heat exchanger for systems with two gas flows. I solved the problem by developing this workbook, which is actually an application of ntu method. Aug 10, 2011 the basic heat exchanger design equation is. I have the tenth edition standard and have a technical question. Heat exchanger g heat exchanger for systems with gas and controlled flows.
A square crosssection is used for the fluid channels instead of circular crosssections, often used in micro heat exchangers. The methodology employed for the design of a phe is the same as for the design of a tubular heat exchanger. Shell and tube heat exchangers basic calculations pdh online. In the previous section we discussed heat transfer in a differential segment of the heat exchanger. An odd number of tube passes is seldom used except the 11 exchanger. Here, we analyze the heat transfer in the entire heat exchanger. The pinch point divides the temperature range into two regions. In the phe the plates create a frame where the plates are pressed with headers and tie bars, and the seal is guaranteed by gaskets. Calculate shell side heat transfer coefficient posted in process heat transfer. There are thus three heat transfer operations that need to be described. Heat exchangers are used in both cooling and heating processes. Solving a traditional shell and tube heat exchanger problem.
Combining each of these resistances in series gives. Unlike other tools, ensures that the calculations are performed step by step to help in understanding the design calculations. Where, we get the a overall overall heat transfer area required from the heat transfer rate equation equation1. We made the selection process as simple as possible and understandable for every specialist. Selection of heat transfer models and fouling coefficients for shell side and tube side. Heat exchanger the purpose of a heat exchanger is just thatto exchange heat. A heat exchanger is a heat transfer device that exchanges heat between two or more process fluids. I had to find how many times a series of pipes should be passed through an industrial chimney in order to heat the water inside the pipes from 5 c to 150 c. Heat exchanger networks are designed through insightful use of pinch analysis. In any heat exchanger there must be a fluid that requires a change in energy heating or cooling and a fluid. Read online basic equations for heat exchanger design sharif book pdf free download link book now. Heat exchangers are devices that regulate efficient heat transfer from one fluid to another. The individual heat transfer coefficients depend on the nature of the heat transfer process, the stream properties and the heat transfer surface arrangements. Here, we will cite only those that are immediately useful for design in shell and tube heat exchangers with sensible heat transfer on the shellside.
The two most common heat exchanger design problems are those of rating and sizing. Multimedia edition of heat exchanger design handbook hedh is the standard reference source for heat transfer and heat exchanger design. A practical guide for planning, selecting and designing of shell and tube exchangers takes users on a stepbystep guide to the design of heat exchangers in daily practice, showing how to determine the effective driving temperature difference for heat transfer. Effective incorporation of heat exchanger networks will minimize the use of utilities, minimize the number of heat exchangers, and minimize costs associated with the design. The heat exchanger is of crossflow configuration and can consist of about 20 unit cells. To develop the methodology for heat exchanger analysis and design, we look at the problem of heat transfer from a fluid inside a tube to another fluid outside. Asme uhx and tema heat exchanger software codeware. Modeling and design of plate heat exchanger intechopen. A closeup view of a section of a watertoair heat exchanger.
In process calculations, the main objectives of heat exchanger calculations are to. I have a lot of familiarity with heat exchangers, especially concentric shell and tube. Heat transfer equation sheet heat conduction rate equations fouriers law heat flux. A practical guide for planning, selecting and designing of shell and tube exchangers takes users on a stepbystep guide to the design of heat exchangers in daily practice, showing how to determine the effective driving temperature difference for. A heat exchanger is a system used to transfer heat between two or more fluids. If the heat exchanger is located at the inlet or discharge of a blower with a pulsating flow, such as a roots type rotary lobe blower, the heat exchanger must be protected from the pulsation by a chambered silencer. English units pdf xlsfigure g52m heat exchanger spec sheet metric units pdf xls. If you need asme uhx and tema mechanical design calculations, drawings and reports then the compress heat exchanger option is for you. Heat exchanger problem calculation lmtd and effectiveness. Plate heat exchanger phe, where corrugated plates are held in contact and the two fluids flow. The heat exchanger design equation can be used to calculate the required heat transfer surface area for a variety of specified fluids, inlet and outlet temperatures and types and configurations of heat exchangers, including counterflow or parallel flow.
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. Balanced counter flow heat exchanger assuming and cc, then the lmtd becomes undefined as. The simplest heat exchanger is one for which the hot and cold fluids move in the same or opposite directions in a concentric tube or doublepipe construction. Q the rate of heat transfer between the two fluids in the heat exchanger in buthr kjhr for s. Heat exchanger design fundamental equation youtube. Plate heat exchangers were first produced in the 1920s and have since been widely used in a great number of sectors a plate exchanger consists of a series of parallel plates that are placed one above the other so as to allow the formation of a series of channels for fluids to flow between them.
The rating program is shown schematically in figure 4. Heat exchangers 73 individual thermal resistances of the system. Understanding heat exchangers types, designs, applications. Qualitative dependence of the fluid temperature on position inside a singlepass heat exchanger is shown in fig. Heat exchanger theory and the heat exchanger design equation. Now, the log mean temperature can be substituted into equation 1 and will yield. A sthe is the most common type of heat exchanger in oil re fineries and other large chemical processes, and is suited for higherpressure applications. They will also calculate the number of tubes needed for a shell and tube heat exchanger and to calculate the pipe length needed for a double pipe heat exchanger. The heart of the heat exchanger contains a fully welded circular plate pack made by pressing and cutting round plates and welding them together. Selection of heat exchanger tema layout and number of. Pdhonline course m371 2 pdh shell and tube heat exchangers. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contact. Heat energy cmu, where m is the body mass, u is the temperature, c is the speci. Both horizontal and vertical heat exchangers can be modeled.
In the analysis of a heat exchanger, or any heat transfer problem, one must begin with an energy balance. Simple or composite wall of some kind divides the two. The model takes heat transferred through both convection and conduction into account. However, the term is commonly used to equipment in which two process streams exchange heat with each other. Hello, im trying to come up with a method on excel to calculate the required surface area for a heat exchanger for a desired output temperature for a fluid which can either be a gas or a liquid.
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. This multimedia edition contains interactive features that bring the rigorous and authoritative material from hedh to life. All books are in clear copy here, and all files are secure so dont worry about it. Up to eight design conditions can be investigated for fixed, utube, kettle and floating tubesheet style exchangers. The heat exchanger must be isolated from system vibrations using flexible piping connections and isolation pads on the mounting feet. Basic equations for heat exchanger design sharif pdf.
Cross flow heat exchanger calculation my engineering world. Calculate shell side heat transfer coefficient process. Pdf heat exchanger types and classifications researchgate. Heat exchanger gtl heat exchanger for systems with gas and thermal liquid flows. Heat exchangers have widespread industrial and domestic applications. Calculate the required heat transfer area based on values needed. The basic component of a heat exchanger can be viewed as a tube with one fluid running through it and another fluid flowing by on the outside.
Numerous articles have been published regarding the advantages of compact heat exchangers. Calculate the required heat transfer rate, q, in btuhr from specified information about fluid flow rates and temperatures. A fourth type of heat exchanger uses an intermediate fluid or solid store to hold heat, which is then moved to the other side of the heat exchanger to be released. Reason for heat exchangers a heat exchanger is a piece of equipment built for. When designing or choosing a heat exchanger there is no single correct solution. With the addition of fouling resistance, the overall heat transfer coefficient, uc. Download basic equations for heat exchanger design sharif book pdf free download link or read online here in pdf. The second heat transfer process is convection, or heat transfer due to a flowing fluid. Equation 4 is valid for a 11 exchanger with 1 shell pass and 1 tube pass in parallel or counterflow.
A 12 shellandtube heat exchanger is illustrated in figure 5. 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. Therefore, it can not be classified as a compact heat exchanger. The equations given in the present chapter are appropriate for the chevron. Actually, this step is going to determine physical properties and shape of the heat exchanger. John richard thome ltcm sgm epfl heat transfer heat exchanger design 1er mars 2008 6 41 the cross. Od is the outside diameter of selected tube size l is the total tube length. The first type of a heat exchanger is called the recuperative type, in which heat are exchanged on either side of a dividing wall by fluids. In convection heat transfer, the heat is moved through bulk transfer of a nonuniform temperature fluid. The equations given in the present chapter are appropriate for the chevron type plates that are used in most industrial applications. The term heat exchanger applies to all equipment used to transfer heat between two streams.
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