If the tube is curved, with the shape of a u, it is called a utube. The heat exchange duty a llows calculation of the log mean. The determination of the optimum heat exchanger design for a specific, well defined application can be regarded as a two stage process. Plate heat exchanger were first introduced in the 1920s. All about double pipe heat exchangers what you need to know. For the purpose of predesigning heat pipe heat exchangers, it is. However, in practice, flow maldistribution is more common and significantly reduces the idealized heat exchanger performance. These are typically used in applications where there is a ducted exhaust stream. Heat pipe heat exchanger design theory by ecool issuu. Industrial equipment and facilities such as boilers, incinerators, chillers, process plants and steel mills generate heat when used. Shell and tube heat exchangers consist of series of tubes.
When used outside of its design heat range, the heat pipes thermal. Although double pipe heat exchangers are the simplest to design, the better choice in the following cases would be the helicalcoil heat exchanger hche. The calculations were made for a constant cold end of the pipe t2 15. Getting the heat transfer coefficient htc or k enables to find the heating area and hence sizing the heat. A heat exchanger follows this principle in its endeavour to reach equalisation. 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 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. 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 is transferred from one fluid to the other through the tube walls, either from tube side to shell side or vice versa. Design and rating of shell and tube heat exchangers page 4 of 30 mnl 032a issued 29 august 08, prepared by j.
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. However, in practice, flow maldistribution is more common and significantly reduces the. E1mnl032a design and rating of shell and tube heat. 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. Unit operations lab heat exchanger 12 theory notes 1. Two types of flow arrangement are possible in a double pipe heat exchanger. 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 pipe heat exchanger design theory linkedin slideshare. 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 heat pipe or twophase thermosyphon device is an important concept in heat exchangers, which can be used in different branches of industry such as. With a plate type heat exchanger, the heat penetrates the surface, which separates the hot medium from the cold one very easily. Pdf heat pipes are very flexible systems with regard to effective. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contact. Heat exchanger, any of several devices that transfer heat from a hot to a cold fluid. Two types of flow arrangement are possible in a doublepipe heat exchanger. Towards an optimal design of heat pipe equipped heat.
In this paper the heat pipe heat exchanger hphe is presented as a new and very attractive heat exchanger type. Heat pipes in modern heat exchangers sciencedirect. Pdf heat pipe in modern heat exchangers researchgate. They are widely used in space heating, refrigeration, air conditioning, power stations, chemical plants, petrochemical plants, petroleum refineries, natural. In a single pass heat exchanger, the fluid goes into one end of a tube and out the other. John richard thome ltcm sgm epfl heat transfer heat exchanger design 1er mars 2008 6 41 the cross.
There are different types of compact heat exchanger design available. Pdf development of a detailed thermal model for designing heat. This double action is economically accomplished by a heat exchanger. 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. 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. Heat pipe selection guide pdf heat pipe basics and demonstration. 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.
Double pipe heat exchanger design with counterflow or. The heat transfer coefficient of an heat exchanger is given by. Paper open access design and fatigue analysis of high. Heat recovery from the steel manufacturing process is a huge. 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. It can be operated as a parallel flow or as a counterflow heat exchanger. 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. Heat pipe heat exchanger design theory heat transfer equipment design. Now it is widely used in a great number of sectors like sugar industry, pharmaceutical industry, food processing industries etc. Double pipe exchangers can be paired in series or in parallel to increase the heat transfer rate through a system without complication. Overall heat transfer coefficient for doublepipe heat. Carbon steel copper inconel monel nickel stainless steel. We discuss the design theory of regenerators in detail in chapter 5.
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. 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. There are several limits that govern heat pipe theory, however in terrestrial applications the capillary limit is the most limiting factor. Passing hot flue gases over the evaporator causes the working. Apr 14, 2016 heat pipe heat exchanger design theory 2. 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. Different types of shell and tube designs are possible. Heat exchanger design an overview sciencedirect topics.
Fluid mechanics, thermal engineering and multiphase flow research lab future, department of mechanical engineering, king mongkuts university of. 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. 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. 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. Heat exchangers are used in both cooling and heating processes. In cross flow heat exchangers, one fluid flows through tubes and second fluid passes around the tubes perpendicularly. Two fluids, of different starting temperatures, flow through the heat exchanger. Convective heat transfer from the outer tube wall to the outside fluid.
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. 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. To meet these objectives background design theory including working fluid choice, boiling and condensation thermal coefficients and the operating states are. One flows through the tubes the tube side and the other flows outside the tubes but inside the shell the shell side. Determination of the heat flux or boiling limit is based on nucleate boiling theory and is comprised of two separate phenomena.
The shellandtube heat exchanger is composed of a shell containing a large number of tubes. Heat pipes and its applications lunds tekniska hogskola. 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. The plateandframe heat exchanger design consists of stacked of corrugated plates which are bonded together. The double pipe heat exchanger is one heat exchanger pipe inside another larger pipe for either counter flow or parallel flow pattern. Heat exchanger and its types engineering solutions.
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. Mathematical model for heat transfer limitations of heat pipe. The calculations of the various variants of the wick structure of heat pipe and working fluid. In many engineering applications it is desirable to increase the temperature of one fluid while cooling another. Towards an optimal design of heat pipe equipped heat exchangers. Heat transfer limitations of water wick heat pipe with sintered capillary. Heat exchanger is a process equipment designed for the effective transfer of heat energy between two fluids. 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. Since the end of the 1970s there are some publications related to heat pipe heat exchangers. 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. A double pipe heat exchanger consists of one pipe inside another. Pdf the conductance of heat pipes is different from line to line inside a. One set of these tubes contains the fluid that must be either heated or.
For the heat transfer to occur two fluids must be at different temperatures and they must come thermal contact. The heat pipe in the heat exchanger can be divided in to three parts. Plate heat exchanger theory phe structure and functional. Design and analysis of a newly installed plate heat exchanger. The double pipe heat exchanger is one of the simplest types of heat exchangers. Fired heaters the selection of a heat exchanger depends on many factors including capital and. 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. The doublepipe heat exchanger is one of the simplest types of heat exchangers.
Heat exchanger theory leads to the basic heat exchanger design equation. It is therefore possible to heat or cool fluids or gases which have minimal energy levels. Design and analysis of a newly installed plate heat. Counter flow heat exchangers are the most efficient of the three types. What are some good books for heat pipe heat exchangers both. Heat exchange involve convection in each fluid and. 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. What are some good books for heat pipe heat exchangers. Heat exchangers are typically classified according to flow arrangement and type of construction. A heat exchanger is a system used to transfer heat between two or more fluids.
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. A heat pipe is a heattransfer device that combines the principles of both thermal conductivity. 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. Beginning with a definition of the problem, including the temperature. In contrast to the parallel flow heat exchanger, the counter flow heat exchanger can have the hottest coldfluid. Heat exchangers design and theory sourcebook internet archive. 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. The two most common heat exchanger design problems are those of rating and sizing. Mechanical design of the flat heat pipe heat exchanger. 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.
Experimental and theoretical investigation of a flat heat pipe heat. Shah r k and w w focke 1988 plate heat exchangers and. A compact heat exchanger is a device characterized by a high heat transfer area per unit volume more than 300 m2m3. Overall heat transfer coefficient for doublepipe heat exchanger. Theory and selection heat exchangers are devices that transfer heat between two luids. The tubes can also be straight, with one or two passes.
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