In this chapter we will examine the basic theory of heat exchangers. Counter flow heat exchangers are the most efficient of the three types. 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. Reason for heat exchangers a heat exchanger is a piece of equipment built for. Based on the type of flow, calculate log mean temperature difference. For example, if it takes 2,000 joules of energy to heat up a block 5 degrees celsius, the formula would look like. Both specific heat and latent heat are properties of a given material. Heat capacity formula the heat capacity, or thermal mass of an object, is defined as the energy in joules required to raise the temperature of a given object by 1. Heat exchanger design to choose a suitable heat exchanger for a certain application requires a level of knowledge and experience. Heat transfer heat exchanger types of heat exchangers. A heat exchanger could remove thermal energy from a fluid used in an airconditioning system or add thermal energy to a system where processes require a certain temperature to work properly. The effect is usually an increase in the temperature of the colder body.
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. Examples of radiation heat transfer in everyday life. This stacked plate arrangement can be more effective, in a given space, than the shell and tube heat exchanger. Heat exchangers jordan university of science and technology. Pdf heat exchangers are used to transfer heat between two sources.
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 many types of heat exchangers can be characterized by flow arrangement and construction. Heat from the ground is absorbed into the fluid and then passes through a heat exchanger into the heat pump. Minimum amount of cooling water vibration free can provide internal demister low air side pressure drops cataract steel industries extended surface heat exchangers contact us today for a free. Heat, energy that is transferred from one body to another as the result of a difference in temperature.
The corresponding intensive property is the specific heat. A heat pump is a device that transfers heat energy from a source of heat to what is called a thermal reservoir. Design and operation of heat exchangers springerlink. This is composed of multiple, thin, slightlyseparated plates that have very large surface areas and fluid flow passages for heat transfer. A procedure for use of the equipment and the software was outlined. Based on the theory proposed by mikic and rohsenow for plain tubes, a theory is developed for finned tubes. Dynamic model and control of heat exchanger networks 6 1 introduction at the brobekk incineration plant in oslo waste from the surrounding area is burned in two furnaces. Heat transfer theory an overview sciencedirect topics. Latent heat is the amount of heat added to or removed from a substance to produce a change in phase.
Pressure drop constraints related to mechanical and operational cost constraints the maximum pressure drop of oil must be smaller than 80 kpa. So, lets take a look at the article given below, in which we have simplified the two for you. In case of solid to liquid phase change, the change in enthalpy required to change its state is known as the enthalpy of fusion, symbol. The term heat exchanger applies to all equipment used to transfer heat between two streams. Pdf performance measurement of plate fin heat exchanger by. Understanding heat exchangers types, designs, applications and. As the worlds largest manufacturer of heat exchangers, we are very proud of our products and services. For the heat transfer to occur two fluids must be at different temperatures and they must come thermal contact. Multimedia edition of heat exchanger design handbook hedh is the standard reference source for heat transfer and heat exchanger design. The theories of transient heat transfer in doublepipe heat exchangers were explained and followed by literature correlations. Mar 31, 2020 radiation heat transfer is the mode of transfer of heat from one place to another in the form of waves called electromagnetic waves. Specific heats and molar heat capacities for various substances at 20 c substance. The heat capacity in calories per gram is called specific heat.
Radiation heat transfer an overview sciencedirect topics. For example, figure 4 shows a hotfluid stream being cooled by a coldfluid stream in a counterflow heat exchanger. This article focuses on heat exchangers, exploring the various designs and types available and. Thank you for purchasing an alfa laval plate heat exchanger. The new theory considers bubble dynamics and interaction between the heat transfer mechanisms of boiling and natural convection, as well as the effect of the fin geometry. 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. Pressure drop calculation for shell and tube and double pipe. Heat transfer heat exchanger types of heat exchangers heat exchangers are classified according to flow arrangement and type of construction. Convection and conduction require the presence of matter as a medium to carry the heat from the hotter to the colder region. Application of heat transfer in daily life examples answers. Heat leaves the warmer body or the hottest fluid, as long as there is a temperature difference, and will be transferred to the cold medium.
Heat capacity, ratio of heat absorbed by a material to the temperature change. Plate heat exchanger working principle, how a plate heat. The fundamentals of heat exchangers wanderlodge gurus. Radiation heat transfer is the process by which the thermal energy is exchanged between two surfaces obeying the laws of electromagnetics. Balanced counter flow heat exchanger assuming and cc, then the lmtd becomes undefined as. Or it can come from contact with the warmer air caused by release of latent heat by direct conduction. The selection of a heat exchanger depends on many factors including capital and operating costs, fouling, corrosion tendency, pressure drop, temperature ranges. Heat transfer theory and heat exchanger equipment are discussed in chapters 3 and 4. Specific heat can also refer to heat capacity at constant volume, cv, or heat capacity at constant pressure, cp. As its name implies, this type of heat exchanger consists of a shell a large vessel.
This multimedia edition contains interactive features that bring the rigorous and authoritative material from hedh to life. 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. Heat exchanger theory leads to the basic heat exchanger design equation. A variety of highintensity heat transfer processes are involved with combustion and chemical reaction in the gasi. Some common examples of radiation are ultraviolet light from the sun, heat from a stove. How ground source heat pumps work ground source heating. The temperature change can come from the absorption of sunlight by the soil or the air itself.
Heat exchanger is a process equipment designed for the effective transfer of heat energy between two fluids. The finite element method in engineering fifth edition, 2011. Specification of tube parameters size, layout, pitch and material. It is therefore possible to heat or cool fluids or gases which have minimal energy levels. Use the trane glossary to find out what heat pump means. The surface temperature is 50 o c, the fluid temperature is 20 o c and the convective heat transfer coefficient is 2000 wm 2o c. Heat exchangers are used in both cooling and heating processes. Heat exchange involve convection in each fluid and conduction through the separating wall. Advances in chemical engineering, volume 9 pdf free download. Shell and tube heat exchanger a shell and tube heat exchanger is a class of heat exchanger. The convective heat transfer between the hotter surface and the colder air can be calculated as. Therefore, it can not be classified as a compact heat exchanger.
The maximum temperatures used for sealing heat exchangers are. The information presented here along with the books referenced here is certainly a good start. To heat a cooler fluid by means of a hotter fluid 2. Conduction convection radiation conduction is the energy of one particle being transferred directly to another by contact. The ground heat exchanger element of a ground source heat pump installation is an infrastructure investment with a design life of over 100 years.
Bg series heat exchangers ctv series heat exchangers 2. However, mutlistream heat exchangers are sometimes used with energy extensive processes, such as lng processing, to reduce capital cost. As the ground stays at a fairly constant temperature under the surface, the heat pump can. Heat capacity is related to specific heat, which is a measure of a particular substances resistance to temperature change in response to a given addition of energy, or heat. The analysis is supported by the concepts and theory in section to support the quantitative analysis of current and potential levels of excess heat recovery in european district heating systems. Specific heat definition of specific heat by the free. Pdf an experimental work is conducted on counter flow plate fin compact heat exchanger using offset strip fin under different mass flow rates. 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. The area density for doublepipe heat exchanger can not be in the order of 700. T 2 t 1 t 1 t 2 acoustic wave in acoustic wave out amplified by t 2 t 1 heat supply at high temperature. The design and testing of practical heat exchange equipment are based on the. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contact.
A heat exchanger is a component that allows the transfer of heat from one fluid liquid or gas to another fluid. Amin sedighiamiri, in nonlinear systems in heat transfer, 2018. Numerical solution of a heat exchanger problem felix brunner dept. 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 two. Pool boiling heat transfer on finned tubesan experimental. A heat exchanger is a piece of equip ment that continually transfers heat from one medium to another.
The many types of heat exchangers can be characterized. They are widely used in space heating, refrigeration, air conditioning, power stations, chemical plants, petrochemical. Typically, a heat exchanger is used with two process streams. Specification of shell side parameters materials, baffles cut. Effectiveness is the best way to compare different types of heat exchangers. It simply uses electricity to move heat from one place to another. Latent and sensible heat north carolina climate office. This is the specific heat of the object a defined physicalchemical property multiplied by its mass and the change in temperature. On standard heat exchangers, there is a 34 or 1 inch female npt drain coupling either on the bottom of the front cover or the bottom of the housing.
The pressure drop calculated for shell and tube heat exchangers is that across the bank of tubes for the tubeside. If two bodies at different temperatures are brought together, energy is transferredi. Fundamental studies have been reported using the cationic liquid ion exchanger di 2ethylhexyl phosphoric acid in the extraction of uranium from wetprocess phosphoric acid h34, yttrium from nitric acid solution hll, nickel and zinc from a waste phsophate solution p9, samarium, neodymium, and cerium from their chloride solutions i2. Neither are concepts of heat exchanger networking procedures 11, nor explicit features of pinchtechnology 12, or industrial symbiosis 14. To reduce the temperature of a hot fluid by means of a cooler fluid 3. 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. One fluid flow inside the tubes, while the other fluid flows across and along the axis of the exchanger, the major components of this exchanger are tubes tube bundles, shell, front end. A procedures manual was created for the doublepipe heat exchanger.
Frictional head loss and pressure drop calculations are done with the excel formulas in the spreadsheet template using the darcy weisbach equation. Heat pumps move thermal energy in the opposite direction of spontaneous heat transfer, by absorbing heat from a cold space and releasing it to a warmer one. Difference between heat and temperature with comparison. A ground source heat pump circulates a mixture of water and antifreeze around a loop of pipe, called a ground loop, which is buried in your garden. The fundamental distinguishing characteristic of a condenser is that it intentionally transfers the latent h. Doublepipe heat exchanger one fluid flows through the smaller pipe while the other fluid flows through the annular space between the two pipes. With a plate type heat exchanger, the heat penetrates the surface, which separates the hot medium from the cold one very easily.
Pdf offdesign behavior analysis and operating curve design. We have prepared this instruction manual to assist you with your alfa laval plate heat exchanger in various situations. Shell and tube heat exchanger are built of round tubes mounted in a cylindrical shell with the tubes parallel to the shell. The concept of heat exchanger efficiency provides a new way for the design and analysis of heat exchangers and heat exchanger networks. A heat exchanger follows this principle in its endeavour to reach equalization. A plate heat exchanger is a type of heat exchanger that uses metal plates to transfer heat between two. The natural laws of physics always allow the driving energy in a system to flow until equilibrium is reached. The system feeding the heat exchanger of a desanation threeway valve located in the field outlet that all its outlet t e p e r a kiseadequate for entering into the m in a disibutedcollector field is sired level in spite of disturba level, cloud v e emirror n t, reflectivior inlet oil te.
A heat pump, as part of a central heating and cooling system, uses the outside air to efficiently heat your home in the winter and cool it in the summer. A heat exchanger is a system used to transfer heat between two or more fluids. Selection of heat exchanger tema layout and number of passes. Excel spreadsheet templates can be downloaded in u. Hydrate prediction and prevention are discussed in chapter 5. Setting upper and lower design limits on tube length. As its name implies, this type of heat exchanger consists of a shell a large vessel with a bundle of tubes inside it.
In convection heat transfer, the heat is moved through bulk transfer of a nonuniform temperature fluid. Heat capacity or thermal capacity is a physical property of matter, defined as the amount of heat to be supplied to a given mass of a material to produce a unit change in its temperature. Section 2 heating and cooling with a heat pump a heat pump is an electrical device that extracts heat from one place and transfers it to another. Heat exchangers 73 individual thermal resistances of the system. Plate heat exchangers are widely used in many other. The plate heat exchanger was invented by dr richard seligman in 1923 and revolutionised methods of indirect heating and cooling of. The aim of this paper is to develop and present the theory of. Mechanical engineering, energy systems and sustainable development vol. 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. Unit operations lab heat exchanger 12 theory notes 1. Some common examples are parallel low heat exchangers, in. We value you as our customer and wish to assure your satisfaction. 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.
Pdf a heat exchanger is a heat transfer device that exchanges heat between two or more process fluids. The second heat transfer process is convection, or heat transfer due to a flowing fluid. Heat exchanger theory and the heat exchanger design. The gas goes through various cleanup and pipedelivery processes to get to our stoves. Unlike burning oil, gas, lpg or biomass, a heat pump produces no carbon emissions on site and no carbon emissions at all, if a renewable source of electricity is. Heat exchanger design john richard thome 1er mars 2008 john richard thome ltcm sgm epfl heat transfer heat exchanger design 1er mars 2008 1 41. The heat exchanger will be supplied with oil, at 55o c 548. Heat exchangers a heat exchanger is a system designed to transfer heat between two fluids to control the temperature of one of the fluids.
An exchangers effectiveness is the ratio of the actual heat transferred to the heat that could be transferred by an exchanger of infinite size. Regenerative versus nonregenerative heat exchangers. 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. Apr 25, 2019 to calculate heat capacity, use the formula. Plate heat exchanger another type of heat exchanger is the plate heat exchanger. Outdoor components of a residential airsource heat pump. On the heat exchanger level there is no use of medium models, but to make it easier for the user to change. Combining each of these resistances in series gives. Latent heat energy required to change the state gas, liquid, solid of a unit mass of material. As a result, they completely missed the trends, patterns, and facts that could have brought the responsible parties to justice, and possibly have prevented the disaster. Helium specific heat, latent heat of fusion, latent heat of. Condensate stabilization, the process of flashing the lighter hydrocarbons to gas and maximizing the recovery of natural gas liquids ngls, is the topic of chapter 6.
A heat exchanger is a device that is used to transfer thermal energy enthalpy between two or more fluids, between a solid surface and. Closeup view of a section of a watertoair heat exchanger. Design improvements of a shell and tube heat exchanger based on practical experience and numerical analysis c. Pdf heat exchanger types and classifications researchgate. It is usually expressed as calories per degree in terms of the actual amount of material being considered, most commonly a mole the molecular weight in grams. Nov 01, 2017 technically, a condenser is a heat exchanger. Unlike a furnace, a heat pump doesnt burn fuel to make heat. Heat exchangers transfer thermal energy from a hotter fluid or gas to a cooler fluid or gas. Heat exchangers are devices used to transfer heat between two or more. In industrial processes, heat energy is transferred by a variety of methods, including conduction in electric resistance heaters. The resulting energy is used to heat pressurized water, which is in turn heat exchanged with cold water from a district heating network operated by viken fjernvarme as. The es extended surface heat exchanger is designed as a compressor intercooler with the ability to cool large volumes of air with.
Sensible heat is the energy required to change the temperature of a substance with no phase change. What is the difference between a condenser and a heat exchanger. It is the most common type of heat exchanger in oil refineries and other large chemical processes. When designing or choosing a heat exchanger there is no single correct solution.