Ees procedures and functions for heat exchanger calculations. Mar 25, 2020 variation of the fluid temperatures in a parallel flow doublepipe heat exchanger. Lets assume we have a perfectly efficient, infinitely long heat exchanger with the same substance on each side, but one enters at 100 f and the other at 0 f. Take a single pass shell and tube exchanger and look at how the temperature changes as we go along the length of it in small segments. Experimental analysis of performance of heat exchanger with plate. 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. Counter flow heat exchangers can allow the cold fluid to exit with a higher temperature than the exiting hot fluid. A heat exchanger can have several different flow patterns. The dimensions and parameters of microchannel with 40 mm. The outlet temperature of the cold fluid never exceeds the outlet temperature of. Parallel and counter flow heat exchanger course code ekb 2091 course name chemical engineering lab 11 group member id mohamed aadil ashraff 1103151010 criteria very poor poor good very good excellen t 1. Note that in a counterflow heat exchanger the outlet temperature of the cold fluid can exceed the outlet temperature of the hot fluid but this cannot happen in a parallel flow system.
Crossflow, parallel flow, and counterflow heat exchanger configurations are three examples. Counter flow heat exchangers are inherently more efficient than parallel flow heat exchangers because they create a more uniform temperature difference between the fluids, over the entire length of the fluid path. Pdf design and development of parallel counter flow heat. Here, we illustrate the development of the effectiveness relation for the doublepipe parallel flow heat exchanger. Heat exchanger has increased immensely from the viewpoint of energy conservation, conversion, recovery, and successful implementation of new energy sources. This heat exchanger consists of two concentric pipes of different diameters. A heat exchanger is a heat transfer device that exchanges heat between two or more process fluids. A heat exchanger can also be operated in counterflow, in which the two fluids flow in parallel but opposite directions. Heat exchanger shell and tube tutorial cfd cfx statical. This file contains notes on the important topic of ees functions for heat exchanger calculations. The 3d fulldomain conjugated model based on actual doublelayer microchannel heat exchanger used in experiment in section 3 is adopted, as shown in fig. Large temperature difference at one end of the heat exchanger causes added thermal stresses and early failure. Heat exchangers with cocurrent flow of the two streams are not very often seen because of the obvious reason that it is possible to do more heat exchange if the two streams are put in countercurrent flow, providing the same heat exchange area, w.
Review of experimental analysis of parallel and counter flow heat. Heat exchanger airwater, applied to the current paper, due to the flow of fluids in the same direction is called the heat exchanger with the parallel flow 1. Why counter flow heat exchangers are more efficient. The flow in a heat exchanger can be arranged as parallel flow, counter flow, and cross flow. Parallel flow and counterflow heat exchangers are often compared. Difference in counter heat exchanger and parallel flow.
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. Temperature profiles in a counter flow and b parallel flow single pass heat exchangers. D counter flow heat exchanger is better then the parallel flow because counter flow type is more effective because of the uniform temperature difference between hot and cold fluids throughout the pass compared to parallel flow configuration. A counterflow heat exchanger is one in which the direction of the flow of one of the working fluids is opposite to the direction to the flow of the other fluid. Temperature profiles in a counterflow and b parallel flow single pass heat exchangers. However, the term is commonly used to equipment in which two process streams exchange heat with each other.
Dec 26, 2016 parallel flow heat exchanger and counter flow heat exchanger hmt tutorial 20 other subjects from ujjwal kumar sen all sfd and bmd tutorials. Pdf material selection and fluid flow analysis of parallel flow. Aircooled heat exchangers are usually used when the heat exchanger outlet temperature is at least 20 of above the maximum expected ambient air temperature. Our main focus is to increase the efficiency of the parallel flow heat exchanger and on the basis of this, decide the shape and size of the heat exchanger.
The major types of heat exchanger include double pipe, shelltube, plate and shell, plate fin, and phase change heat exchangers. Heat exchangers have widespread industrial and domestic applications. I made a parallelseries heat exchanger for show and tell for the students. However, there are applications where parallel flow has its benefits, such as when limiting the transfer of heat is recommended. This hx works in parallel flow, where the water flows by 3ms and the oil is half of the water and the convection is neglected outer the shell. How lmtd of counter flow heat exchanger is greater than. These notes were prepared while teaching heat transfer course to the m. Parallel flow heat exchanger and counter flow heat. Pdf analysis of a parallelflow heat exchanger with a heat source. The inlet temperature of cooled fluid has insignificant impact on.
Joseph engineering college, vamanjoor, mangalore, india. A counterflow heat exchanger will require less heat exchange surface area than a parallel flow heat exchanger for the same heat transfer rate and the same inlet and outlet temperatures for the fluids. The materialprocess decision on a parallel flow heat exchanger. However ordinary heat exchangers might be extremely dissimilar in design and construction and might be of the single or twophase kind, their modes of operation and efficiency are largely established by the direction of the fluid flow inside the exchanger. Numerical simulations have been performed to investigate the fluid flow and heat transfer characteristics of microchannel heat exchanger. Entropy generation analysis of parallel and counterflow threefluid. The chemical enters at 20 c at a rate of 3 kgs, while the water enters at 110 c at a rate of 2 kgs. Therefore, different types of heat exchangers have different effectiveness relations. The present work is directed towards the modeling of shell and tube parallel flow heat exchanger in solid works 2014 and setting up of flow simulation in solid works by inserting boundary. Lab 5 parallel and counter flow heat exchanger faculty.
Difference in counter heat exchanger and parallel flow heat. Heat exchanger dealers in uae heat exchangers are devices that are used to transfer heat from one medium to another or from one liquid to another without the two fluids having to come into contact with each other. Variation of the fluid temperatures in a parallelflow doublepipe heat exchanger. Heat exchangers are used in engines of cars, ships, and planes to improve the efficiency of the engine and are also used in refrigerators and air conditioners. But of the three, the counter flow heat exchanger design is the most efficient when comparing heat transfer rate.
Aircooled heat exchangers 12631 the intake of the unit or other nearby units. What is application of parallel flow heat exchanger. Pdf a design of the control of the internal fluid temperature at the outlet of a parallelflow heat exchanger by manipulating the inlet external fluid. In general, parallel flow heat exchangers considered less efficient than counter flow heat exchangers in terms of transferring heat from one fluid to another. If the overall heat transfer coefficient of the heat exchanger is 700 wm 2 c, determine the length of the tube required in order to heat the water to 80 c using a the lmtd method and b the e ntu method. The present work is directed towards the modeling of shell and tube parallel flow heat. C the valve to adjust hot flow rate does not work so we will measurement by ourselves. In this work, heat transfer coefficients of shell and helically coiled tube heat exchanger using al 2 o 3 water nanofluid were studied. Heat exchangers 73 individual thermal resistances of the system. Heattransfer characteristics of wet heat exchangers in.
Another advantage if parallel flow heat exchangers are used is that outlet temperature of the fluid being cooled can reach a limiting temperature. Heat exchanger transfer thermal energy from one medium to another. The two most common heat exchanger design problems are those of rating and sizing. July 2016, volume 3, issue 7 jetir issn 2349 5162 numerical. Plate heat exchanger phe, where corrugated plates are held in contact and the two fluids flow. The slightest difference in plumbing can make a flow difference. Difference in counter and parallel flow heat exchanger. This page was last edited on 23 decemberat is the log mean temperature difference, which is the suitable form of the average temperature difference for use in the analysis of heat exchangers. A double pipe heat exchanger consists of one pipe inside another. Investigation of fluid flow and heat transfer characteristics. A free powerpoint ppt presentation displayed as a flash slide show on id.
It is referred to as a laminar flow heat exchanger if the surface area density is above about 3000 m2m 3 914 ft2ft3, and as a micro heat exchanger if the surface area density is above about 10,000 m2m 3 3050 ft2ft3. Parallel flow to tubes platefin tubefin ordinary separating wall heatpipe wall rotary fixedmatrix rotating. Experimental study on parallel and counter flow configuration. This hx works in parallel flow, where the water flows by 3ms and the oil is half of the water and the convection is. There have been reported cases of heat exchanger failure in service due to the. The simplest heat exchanger is one for which the hot and cold fluids move in the same or opposite directions. Click download or read online button to get fundamentals of heat exchanger design book now. Fundamentals of heat exchanger design download ebook pdf. 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. Ppt heat exchanger powerpoint presentation free to. This study was done by changing the parallel flow configuration into counter flow configuration under laminar flow regime. Parallel flow heat exchanger and counter flow heat exchanger. You will need some way to monitor and control flow.
Parallel and counter flow designs heat exchangers engineers. Entropy generation analysis of parallel and counterflow threefluid heat. Design and development of parallel counter flow heat exchanger. Large volumes of vapor may be condensed using this type of heat exchanger flow. Asee 2014 zone i conference, april 35, 2014, university of. Previous question next question get more help from chegg. While parallel flow arrangement can be beneficial, under certain conditions that reduce the limiting temperature, channeling problems can occur or freeze may be caused at shutdown. Representation of parallel flow heat exchanger heat transfer. The term heat exchanger applies to all equipment used to transfer heat between two streams. Determination of over all heat transfer coefficient of composite wall. There are probably heat exchanger in your office building which heat transfer from hot water to the ventilation. Temperature difference leads to heat transfer and heat transfer changes the temperature difference. Hot air recirculation tends to reduce the capacity of the heat exchanger, thereby requiring a higher air flow rate andor more heat transfer surface. Heat transferheat exchangers wikibooks, open books for an.
The wet heat exchanger has a higher effectiveness in counter flow than parallel flow. If the inline pdf is not rendering correctly, you can download the pdf file here. Plate heat exchanger working principle, how a plate heat. Pdf design and development of parallel counter flow.
Each of the three types of heat exchangers has advantages and disadvantages. Lab 5 parallel and counter flow heat exchanger faculty of. Note that in a counter flow heat exchanger the outlet temperature of the cold fluid can exceed the outlet temperature of the hot fluid but this cannot happen in a parallel flow system. Determination of thermal conductivity of insulation powder. A heat exchanger is a device that is used to transfer thermal energy enthalpy between two or more fluids, between a solid surface and. Pdf in this work, a modified analysis of a parallelflow plate heat exchanger that takes into account a volumetrically uniform. Hot air recirculation tends to reduce the capacity of the heat exchanger, thereby requiring a higher air flow rate andor more heattransfer surface. The inlet temperature of cooled fluid has insignificant impact on heat exchanger effectiveness. Global control strategy of a parallelflow heat exchanger. Combining each of these resistances in series gives. It can be operated as a parallel flow or as a counterflow heat exchanger. However ordinary heat exchangers might be extremely dissimilar in design and construction and might be of the single or twophase kind, their modes of operation and efficiency are largely established by the. The most common arrangements for flow paths within a heat exchanger are counterflow and parallel flow. Double pipe heat exchanger design with counterflow or.
Asee 2014 zone i conference, april 35, 2014, university. Chapter 5 heat exchangers faculty of engineering and. If water is kept above 32 deg f, freezing can be avoided. Heat is transferred from the warm fluid through the wall of the inner tube the socalled heating surface to the cold fluid. Experimental investigation of heat transfer characteristics on a gas. Representation of parallel flow heat exchanger heat transfer home category mechanical engineering mcq questions and answers heat transfer previous. Here, we illustrate the development of the effectiveness relation for the doublepipe parallelflow heat exchanger. The design of parallel flow heat exchanger is advantageous when two fluids are required to be. Faculty of chemical engineering laboratory submission form name vengadeesh verasamy 1103151018 title of experiment experiment 5. This site is like a library, use search box in the widget to get ebook that you want. Parallel is best, but flow will follow the path of least resistance. Parallel and counter flow designs heat exchangers although ordinary heat exchangers may be extremely different in design and construction and may be of the single or twophase type, their modes of operation and effectiveness are largely determined by the direction of the fluid flow within the exchanger. The objective of this experiment is study the heat transfer phenomena in parallel and counter flow arrangements, to calculate the lmtd for both parallel and counter flow. This engineering calculator will determine a number of variables for the most common arrangements or flow paths within heat exchangers.
Heat exchangers jordan university of science and technology. In a parallel flow exchanger, both fluids in the heat exchanger flow in the same direction. If we comnpare parallel and counterflow heat exchanger, for same heat exchange area and overall heat exchange coeficient the heat transferred in c view the full answer. 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. Parallel flow, counter flow, heat transfer coefficient. Here, we illustrate the development of the effectiveness. Parallel flow heat exchanger and counter flow heat exchanger hmt tutorial 20 other subjects from ujjwal kumar sen all sfd and bmd tutorials. Heat transfer lab manual pdf ht lab manual pdf notes. I made a parallel series heat exchanger for show and tell for the students. This experiment was conducted by using parallel and counter flow heat exchanger to study, understand and visualise the heat transfer phenomena in both parallel and counter flow equipment. The heat exchanger must be isolated from system vibrations using flexible piping connections and isolation pads on the mounting feet. Heat exchangers are typically classified according to flow arrangement and type of construction. It is common knowledge amongst heat exchanger designers that a counter flow heat exchanger installation is more efficient than the parallel flow alternative, but for everyone else it can be a bit of a mystery. The effectiveness of a heat exchanger depends on the geometry of the heat exchanger as well as the flow arrangement.
907 1352 1601 1446 859 172 138 465 570 36 124 1373 1183 805 65 1438 826 84 1140 1121 1286 232 1058 1660 587 511 1285 1129 1224 1275 72 1535 558 850 120 381 1150 156 1316 785 1231 347 1157 512 520 594