Types of heat exchangers shell and tube, plate type. Heat is transferred from the hot fluid to the wall by convection, through the wall by conduction and from the wall to the cold fluid by convection. The heat exchanger design can provide high power if the heat transfers within the storage material is high. Pdf modelling, simulation, control of heat exchanger by using. Jan 04, 2016 although heat transfer is typically efficient, controlling the temperature of the fluid being heated at a specific and stable setpoint can be challenging. This shows that temperature sensors located on the external surface of the exchanger. Heat exchanger theory and the heat exchanger design equation. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contact. Heat transfer processes set limits to the performance of aerospace components and systems and the subject is one of an enormous range of application. Pdf this paper analyzes the performance of different controllers such as feedback. The transfer functions are estimated using synthetic temperature responses. Ordinary differential equation of heat exchanger is using to build the model of. To demonstrate the basic equations of heat exchanger operation. The goal of the analysis is to find transfer functions relating the exiting fluid temperature t l,t to the entering fluid temperature t 0,t and the steam temperature tvt.
D o l and u is the overall heat transfer coefficient. 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. However, most of the pcm present low thermal conductivity and, therefore, require additional improvements. Heat exchangers are used in both cooling and heating processes.
Use the tfest command specifying one pole, no zeroes, and an unknown inputoutput delay to estimate a transfer function. Reason for heat exchangers a heat exchanger is a piece of equipment built for efficient heat transfer from one medium to another hot and cold fluid. A heat exchanger is a system used to transfer heat between two or more fluids. Heat exchanger effectiveness 2274 1 the effectiveness of a given heat exchanger can be defined as for cold stream c and hot stream h comparing the actual heat transfer with the maximum possible for the given geometry and material flows. A procedure for use of the equipment and the software was outlined. This includes knowledge of precautions regarding media type, pressures, temperatures in the heat exchanger as well as specific precautions required by the process. Heat exchangers are devices designed to transfer heat between two or more fluidsi. The exchange can take place between a process stream and a utility stream cold water, pressurized steam, etc, a process stream and a power source electric heat, or between two process streams resulting in energy integration and reduction of external heat sources. A heat exchanger involves two flowing fluids separated by a solid wall. Heat exchanger theory leads to the basic heat exchanger design equation. Regardless of the function the heat exchanger fulfills, in order to transfer heat, the fluids involved must be at different temperatures and they must come into thermal contact. Control engineering applying heat exchanger control strategies. 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. Dynamic response and control of multipass heat exchangers.
A procedures manual was created for the doublepipe heat exchanger. A variety of highintensity heat transfer processes are involved with combustion and chemical reaction in the gasi. Download heat transfer calculations by myer kutz esm. Transfer function model of heat exchanger system is. Fluid engine oil sea water inlet temperature, c 65 20 outlet temperature, c 55 25 heat load, kw 117. Controller design for temperature control of heat exchanger. The theories of transient heat transfer in doublepipe heat exchangers were explained and followed by literature correlations. Introduction to engineering heat transfer these notes provide an introduction to engineering heat transfer. The optimum heat transfer rate takes place in a balanced counter flow heat exchanger and by using this optimum rate of heat transfer, the concept of heat exchanger efficiency is introduced as the. The heat transfer processes involved in these stages are generally less intense. Pdhonline course m371 2 pdh shell and tube heat exchangers.
A heat exchanger is a heat transfer device that exchanges heat between two or more process fluids. However, these challenges can be overcome by understanding heat exchanger control schemes implemented in industry. Regardless of the function the heat exchanger fulfills, in order to transfer heat the fluids involved must be at different temperatures and they must come into thermal contact. Background a heat exchanger is a heat transfer device whose purpose is the transfer of energy from one moving fluid stream to another moving fluid stream. Depending on the type of heat exchanger employed, the heat transferring process can be gastogas, liquidtogas, or liquidtoliquid and occur through a solid separator, which prevents mixing of the. The heat exchanger shall be operated by persons who have studied the instructions in this manual and have knowledge of the process. Shell and tube heat exchanger traditional solution in order to determine the amount of heat transfer occurring in tube, one may be inclined to utilize the relationship.
Heat exchangers are used to transfer heat between two sources. T 1 where q is the heat transfer rate, u is the overall heat transfer coefficient, a is the area the heat transfer is occurring over, and. The notes are intended to describe the three types of heat transfer and provide. Therefore, the comprehensive performance evaluation method of a heat exchanger for otec power generation, which considers the tradeoff of the heat transfer performance and the pressure drop, is required for the selection and design of the heat exchangers, as well as the improvement of heat exchanger performance. 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 exchanger network design, monitoring and optimization. The heat exchanger must be isolated from system vibrations using flexible piping connections and isolation pads on the mounting feet. The main purpose of a heat exchanger system is to transfer heat from a hot fluid to a cooler fluid, so temperature control of outlet fluid is. Calculate the required heat transfer rate, q, in btuhr from specified information about fluid flow rates and temperatures. Compute heat exchanger heat transfer factor for each exchanger in the network. Solving a traditional shell and tube heat exchanger problem. Modeling and control of a real time shell and tube heat exchanger. Modeling and simulation of heat exchanger used in soda. Different types of heat exchangers in addition, the overall heat transfer equation for the exchanger must be solved simultaneously.
To understand the basic operation of heat exchangers. Defining the minimum and maximum heat capacity rates cmin and cmax as. 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. Make an initial estimate of the overall heat transfer coefficient, u, based on the fluids involved. In a heat exchanger, there is no direct contact between the two fluids. The fraction is the heat exchanger effectiveness, and it is a function of the number of transfer units, or ntu, a measure of the ease with which heat moves. Heat exchangers have widespread industrial and domestic applications. 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. Parameter and boundary estimation 34 estimation of parameters in models 35 upper bounds of heat transfer from boxes 36 estimating freezing. Pdf controller design for temperature control of heat exchanger. Understanding heat exchangers types, designs, applications. Dynamic model and control of heat exchanger networks. Matlab simulation of temperature control of heat exchanger using. Abstract this paper discusses irrational transfer function representation for a typical thickwalled double pipe heat exchanger.
From the physics of the problem we know that the heat exchanger can be described by a first order system with delay. 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 overall heattransfer coefficient of the exchanger is 300 wm2 k, and the area for heat transfer is 15. Modeling and simulation of heat exchanger used in soda recovery.
The transfer functions obtained by dynamic analysis of one shell pass and. The gas goes through various cleanup and pipedelivery processes to get to our stoves. The addition of high conductive particles or structures in the pcm can significantly increase the heat transfer rate. Design a double pipe heat exchanger with bare inner multitubes that can be used to cool engine oil with cold sea water. 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. Heat can flow only from the hotter to the cooler fluid. The transfer function of control elements like sensor, controller, actuator and heat exchanger used in temperature control loop have. Basic heat exchanger performance evaluation method on otec. 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. A proper model of heat exchanger is required for the purpose of monitoring and control. This means that the plate heat exchanger can remain in service far longer between cleaning intervals. In heat exchangers, there are usually no external heat and work interactions. Estimating transfer function models for a heat exchanger. 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.
They are widely used in space heating, refrigeration, air conditioning, power stations, chemical plants, petrochemical plants, petroleum refineries, natural. The heat exchanger effectiveness is defined as the ratio of actual heat transfer to the maximum possible heat transfer. Heat exchanger design an overview sciencedirect topics. They are widely used in space heating, refrigeration, air conditioning, power stations, chemical plants. Heat exchangers jordan university of science and technology. Typically, a heat exchanger is used with two process streams.
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