Heat exchanger design an overview sciencedirect topics. Towards an optimal design of heat pipe equipped heat exchangers. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contact. This double action is economically accomplished by a heat exchanger. In cross flow heat exchangers, one fluid flows through tubes and second fluid passes around the tubes perpendicularly. The heat transfer coefficient of an heat exchanger is given by. It can be operated as a parallel flow or as a counterflow heat exchanger. Two types of flow arrangement are possible in a double pipe heat exchanger. Heat pipes in modern heat exchangers sciencedirect. When used outside of its design heat range, the heat pipes thermal. A heat exchanger follows this principle in its endeavour to reach equalisation. Design and analysis of a finnedtube heat exchanger using winglets 183 somchai wongwises, yutasak chokeman, effect of fin pitch and number of tube rows on the air side performance of herringbone wavy fin and tube heat exchangers.
The two most common heat exchanger design problems are those of rating and sizing. The double pipe heat exchanger is one of the simplest types of heat exchangers. 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. Overall heat transfer coefficient for doublepipe heat exchanger calibrate thermocouples pump water through inner pipe of doublepipe heat exchanger rate determined by rotameter flow steam through outer pipe of doublepipe heat exchanger measure rate by pail and scale. Heat pipes and its applications lunds tekniska hogskola. Heat pipe selection guide pdf heat pipe basics and demonstration.
Chapter 4 presents a first step towards numerical simulation of the flow in a thermosyphon, to gain more understanding of the experimental results obtained in chapter 2 especially with respect to the operating limit in a single heat pipe. The double pipe heat exchanger is one heat exchanger pipe inside another larger pipe for either counter flow or parallel flow pattern. For the purpose of predesigning heat pipe heat exchangers, it is. Pdf heat pipe in modern heat exchangers researchgate. Heat transfer limitations of water wick heat pipe with sintered capillary. The main advantage of the hche, like that for the spiral heat exchanger she, is its highly efficient use of space, especially when its limited and not enough straight pipe can be laid. In parallel flow, both the hot and cold fluids enter the heat exchanger at the same end and move in the same direction, as shown in figure 1.
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. In contrast to the parallel flow heat exchanger, the counter flow heat exchanger can have the hottest coldfluid. Although double pipe heat exchangers are the simplest to design, the better choice in the following cases would be the helicalcoil heat exchanger hche. 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. Heat exchangers design and theory sourcebook internet archive. John richard thome ltcm sgm epfl heat transfer heat exchanger design 1er mars 2008 6 41 the cross. Heat exchanger and its types engineering solutions. It is therefore possible to heat or cool fluids or gases which have minimal energy levels. The heat pipe in the heat exchanger can be divided in to three parts. There are different types of compact heat exchanger design available. All about double pipe heat exchangers what you need to know.
With a plate type heat exchanger, the heat penetrates the surface, which separates the hot medium from the cold one very easily. Theory and selection heat exchangers are devices that transfer heat between two luids. However, in practice, flow maldistribution is more common and significantly reduces the. However, in practice, flow maldistribution is more common and significantly reduces the idealized heat exchanger performance. 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. Fired heaters the selection of a heat exchanger depends on many factors including capital and. 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 double pipe construction.
The first stage is concerned with the selection of the most appropriate heat exchanger type, for example, the choice of a shell and tube exchanger as opposed to a plate, rotating wheel, heat pipe, etc. Heat exchangers are used in both cooling and heating processes. Air that is exhausted from a building, to maintain favorable indoor air quality, has been cooled summer or heated winter to the typical space temperature of 70 to 75f. The determination of the optimum heat exchanger design for a specific, well defined application can be regarded as a two stage process. It is called a double pipe exchanger because one fluid flows inside a pipe and the other fluid flows between that pipe and another pipe that surrounds the first.
Shell and tube heat exchangers consist of series of tubes. A compact heat exchanger is a device characterized by a high heat transfer area per unit volume more than 300 m2m3. Pdf development of a detailed thermal model for designing heat. In the first part of the paper a presentation of the modelization of the hphe is given, in the second part some technologocal considerations are developped and in the third part two exemples of industrial applications are described. Heat pipe heat exchanger design theory linkedin slideshare. Heat exchange involve convection in each fluid and. If the tube is curved, with the shape of a u, it is called a utube. These are typically used in applications where there is a ducted exhaust stream. 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. Heat pipe heat exchanger design theory by ecool issuu. Unit operations lab heat exchanger 12 theory notes 1. The goals of this proje ct were to design a plate heat exchanger apparatus and evaluate the potential of replacing the current double pipe heat exchanger by this newly designed plate heat exchanger for the unit operation laboratory course. However, since double pipe heat exchangers are simple, they are used to teach heat exchanger design basics to students as the fundamental rules for all heat exchangers are the same. Heat exchanger theory and the heat exchanger design equation.
Heat recovery from the steel manufacturing process is a huge. Apr 14, 2016 heat pipe heat exchanger design theory 2. Mathematical model for heat transfer limitations of heat pipe. The calculations were made for a constant cold end of the pipe t2 15. Experimental and theoretical investigation of a flat heat pipe heat. In this paper the heat pipe heat exchanger hphe is presented as a new and very attractive heat exchanger type. The heat exchange duty a llows calculation of the log mean. Heat pipe heat exchanger design theory heat transfer equipment design. What are some good books for heat pipe heat exchangers. A unique, singlesource volume offering essential material on heat exchanger design in a unified approach suitable to many applications, fundamentals of heat exchanger design details an indepth thermal and hydraulic design theory underlying twofluid heat exchangers for steadystate operation. Gallery the corrosion and maintenance problems faced by conventional heat exchangers in heat recovery systems could be addressed using the heat pipe heat transfer technology. The double pipe heat exchanger is a small, modular design that is most useful in applications where conventional shell and tube exchangers are too large or too expensive to use. Double pipe heat exchanger design requires use of the heat transfer rate, the log mean temperature difference, and an estimate of the overall heat transfer coefficient to calculate the estimated heat transfer surface area. Jul 01, 2016 because the cooler fluid exists the counter flow heat exchanger at the end where the hot fluid enters the heat exchanger, the cooler fluid will approach the inlet temperature of the hot fluid.
One flows through the tubes the tube side and the other flows outside the tubes but inside the shell the shell side. The total heat load a heat pipe can carry is a function of total length, evaporator and condenser length, diameter, and orientation with respect to gravity. Two types of flow arrangement are possible in a doublepipe heat exchanger. E1mnl032a design and rating of shell and tube heat. For the heat transfer to occur two fluids must be at different temperatures and they must come thermal contact. Double pipe heat exchanger design with counterflow or.
In many engineering applications it is desirable to increase the temperature of one fluid while cooling another. Design and analysis of a newly installed plate heat. Convective heat transfer from the outer tube wall to the outside fluid. The calculations of the various variants of the wick structure of heat pipe and working fluid. Heat is transferred from one fluid to the other through the tube walls, either from tube side to shell side or vice versa. Fluid mechanics, thermal engineering and multiphase flow research lab future, department of mechanical engineering, king mongkuts university of. A heat pipe is a heattransfer device that combines the principles of both thermal conductivity. Getting the heat transfer coefficient htc or k enables to find the heating area and hence sizing the heat. Plate heat exchanger were first introduced in the 1920s. The shellandtube heat exchanger is composed of a shell containing a large number of tubes. Pdf heat pipes are very flexible systems with regard to effective.
Counter flow heat exchangers are the most efficient of the three types. Plate heat exchanger theory phe structure and functional. The doublepipe heat exchanger is one of the simplest types of heat exchangers. Heat exchanger, any of several devices that transfer heat from a hot to a cold fluid. Design and rating of shell and tube heat exchangers page 4 of 30 mnl 032a issued 29 august 08, prepared by j. Towards an optimal design of heat pipe equipped heat. Industrial equipment and facilities such as boilers, incinerators, chillers, process plants and steel mills generate heat when used. Passing hot flue gases over the evaporator causes the working. They are widely used in space heating, refrigeration, air conditioning, power stations, chemical plants, petrochemical plants, petroleum refineries, natural. Heat exchanger theory leads to the basic heat exchanger design equation. Determination of the heat flux or boiling limit is based on nucleate boiling theory and is comprised of two separate phenomena.
Beginning with a definition of the problem, including the temperature. To meet these objectives background design theory including working fluid choice, boiling and condensation thermal coefficients and the operating states are. The plateandframe heat exchanger design consists of stacked of corrugated plates which are bonded together. The common idealization in the basic tubular heat exchanger design theory is that the fluid is distributed uniformly at the inlet of the exchanger on each fluid side throughout the core. Now it is widely used in a great number of sectors like sugar industry, pharmaceutical industry, food processing industries etc. The simulation results of the heat exchanger show that under the condition of guaranteeing the outlet temperature of fresh water, the required area of the heat exchanger is 4.
Pdf the conductance of heat pipes is different from line to line inside a. Project description by means of knowledge about the theory of heat pipes, one is now able to carry out a basic calculation of a heat pipe. 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. The heat pipe or twophase thermosyphon device is an important concept in heat exchangers, which can be used in different branches of industry such as. The tubes can also be straight, with one or two passes. Overall heat transfer coefficient for doublepipe heat. Double pipe exchangers can be paired in series or in parallel to increase the heat transfer rate through a system without complication. A double pipe heat exchanger consists of one pipe inside another. Shah r k and w w focke 1988 plate heat exchangers and. Heat exchangers are typically classified according to flow arrangement and type of construction. What are some good books for heat pipe heat exchangers both. One set of these tubes contains the fluid that must be either heated or.
Heat exchanger is a process equipment designed for the effective transfer of heat energy between two fluids. 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. Design and analysis of a newly installed plate heat exchanger. Different types of shell and tube designs are possible. Since the end of the 1970s there are some publications related to heat pipe heat exchangers. Carbon steel copper inconel monel nickel stainless steel.
It is called a doublepipe exchanger because one fluid flows inside a pipe and the other fluid flows between that pipe and another pipe that surrounds the first. There are several limits that govern heat pipe theory, however in terrestrial applications the capillary limit is the most limiting factor. A heat exchanger is a system used to transfer heat between two or more fluids. 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. Mechanical design of the flat heat pipe heat exchanger. Overall heat transfer coefficient for doublepipe heat exchanger. The heat pipe heat exchanger used for gasgas heat recovery is essentially a bundle of finned heat pipes assembled like a conventional aircooled heat exchanger. Local heat exchange coefficients calculated as per the local geometry as well as dimensionless numbers such as reynolds re, prandlt pr and nusselt nu.
Two fluids, of different starting temperatures, flow through the heat exchanger. In a single pass heat exchanger, the fluid goes into one end of a tube and out the other. We discuss the design theory of regenerators in detail in chapter 5. Paper open access design and fatigue analysis of high. A heat pipe heat recovery heat exchanger for a minidrier.
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