Designs of Heat Exchangers Essay Example for Free

blueprints of rut Exchangers Essay light communicate from one gist to an otherwise plays a study role in the off cut back of some commonly use technology today. The groove transfer is through with(p) to control temperature, to lovingness up a cooler substance, or to cool down a hotter substance. This cognitive operation is do by a machine called the heat exchanger. The heat exchanger is commonly used in the lay heating, in cooling of engines, refrigeration and other processes which need temperature control. They be classified according to their fall down arrangement end. One is the parallel-flow trope which the ii substance flow from the same direction and exit at the same direction to a fault.The other one is the counter-flow design on which the politics flow on opposite direction. The blend in one is the cross-flow heat exchanger where the melteds flow perpendicular to each other (Heat Exchanger Design, Inc. 2009). Figure 1. Parallel-flow and Counter-flow D esign (Engineering Edge 2009) in that location are also several types of heat exchangers depending on its design. Some are plate and tube heat exchangers, plate heat exchangers, Regenerative heat exchangers and many others. The shell and tube design of the heat-exchanger consists of two sets of tubes.The first set of tubes is where the cooled or heated fluid flows and on the other set of tubes is the fluid that needful to be heated or cooled. The fluids are separated by the tubes wall. This design ensures a better protection from leakage because of the tube design. So this design is ideal for the treatment of super advance fluids (Kakac Liu 20028). The plate heat exchanger is consisting of multiple, thin and slightly separated plates which allow a larger fluid flow area fro heat transfer. It is said to be more effective than the shell and tube design because it provides more surface area for heat transfer.Additionally, the plate heat exchangers have recent developments on it s brazing and gasket that makes it operable to use than other heat exchangers. However, the plate heat exchanger is needs a lot of space and it is more susceptible to leakage (Wang, Sunden Manglik 2007). The regenerative heat exchangers are heat exchangers that make use of the heated fluid after a process to be the heating fluid for the next process. This design can be on a plate or shell and tube structure. The advantages of this type are adapted from the design it is structured.Furthermore, this design brought an economical perspective to the first two designs. On the other hand, this design is only in guide for the use of gas substances as fluids (Saunders 1988). Figure 4. Regenerative Heat Exchanger (Defense Research Development Organization 2004) The adiabatic wheel heat exchanger is a machine which uses a third substance, fluid or solid, to transfer heat between the streams. The disadvantage of this design is that there will be a small miscellanea of the two streams in the process of heat transfer (Saunders 1988). The plate fin heat exchanger is highly used in different industries.The plate-fin heat exchangers utilize plates and finned chambers for relatively high heat transfer. It is prefer by other industries because of its ability to transfer heat with to small difference between the streams. Additionally, it has a boneheaded design and is very lightweight (Kakac Liu 200217). Another type is the fluid heat exchangers. The process being done is by showering fluids to a gas stream in an upward direction. The process is used in machines that need gas cooling and purification at the same time (Saunders 1988). Figure 6. Thermal Fluid Heat Exchanger (Thermotech Industries n.d. ) A burn out heat recovery unit is a heat exchanger that recovers waste heat from other mechanism and uses it to transfer heat the fluid being heating. This design is very lovable for refineries and plants since they have an abundant amount of waste heat from their machineri es. This design is very economical since waste recycled to something serviceable (Saunders 1988). Figure 7. Waste Heat Recovery Unit (Turner 2005) Dynamic or scraped surface heat exchangers are heat exchangers that have high maintenance cost because of the constant surface scraping.The scraping is due to the process these machines are used. Such processes are heating and cooling of high-viscosity fluids and other highly fouling substance. However, this design has a sustainable heat transfer and it avoids fouling of the surface of transfer (Saunders 1988). Figure 8. Scraped Surface Heat Exchanger (GEA Niro 2008) The phase-change heat exchangers are machines that utilizes transparent and gas phase in heat transfer. These heat exchangers either heat a liquid to boil and evaporate or cool hot gases to condense. This process is common in distillation set ups.The distillation is a process of which a liquid is heated up and cooled down to remove impurities. It is also used in motive pla nts such as nuclear power plants and fossil fuel plants. These power plants usually use steam driven turbines to generate electricity. In which the steam came from the heat exchange between the heater and the liquid (Saunders 1988). The heat exchangers above are heat exchangers which utilizes a wall to separate the two streams of liquids. The classifications above are based on the design of which how the two streams are separated.However, there are other heat exchangers that do not use walls or separators. These are called direct contact heat exchangers. These heat exchangers use two different phases in heat transfer (Saunders 1988). Figure 9. Phase-changed Heat Exchanger (NationMaster. com 2003) There are other heat exchangers in the market today. Some of these are the multi-phase heat exchangers and spiral heat exchangers. Selecting a proper heat exchanger can be a challenging task. It requires technical acquaintance about the designs since there are many factors to be taken into consideration.Some are temperature ranges, the composition of the substance to be heated and pressure limits. That is why the decision about the design is made by a computer program or an engineer. Additionally, large companies and corporations tend to design their own heat exchanger to tend to their needs (Wang, Sunden Manglik 2007). Heat exchangers are seen everywhere without you noticing that they are there. The advances in the technology of heat exchangers can kindle better results for engineers, researcher and many industrialists since it will increase the efficiency of the process which common machines have today. amount of References Defense Research Development Organization (2004). Mechanical Propulsion System. Technology Focus online available from http//www. drdo. org/ bar/techfocus/oct04/welcomeoct04. html 17 April 2009 Engineering Edge. (2009). Heat Transfer. online available from http//www. engineersedge. com/heat_transfer/parallel_counter_flow_designs. htm 17 Apri l 2009 GEA Niro. (2008). Preheating System. online available from http//www. niro. com/niro/CMSDoc. nsf/WebDoc/ndkw5y7gby 17 April 2009 Heat Exchanger Design, Inc. (2009).Shell and Tube Heat Exchanger. online available from http//www. hed-inc. com/shell-tube. html 17 April 2009 Kakac, S. Liu, H. (2002). Heat Exchangers Selection, Rating and Thermal Design (2nd Edition). CRC Press Linde Engineering Division (2005). denture Fin Heat Exchangers. online available from http//www. linde-engineering. com/plant_components/plateheatexchanger_aluminium. php 17 April 2009 NationMaster. com (2003). Heat Exchanger. online available from http//www. nationmaster. com/encyclopedia/Heat-exchanger 17 April 2009 Saunders, E. A. (1988).Heat Exchanges Selection, Design and Construction. New York Longman scientific and Technical Thermotech Industries (n. d. ) Products. online available from http//www. thermotech-finnedtubes. com/products. htm 17 April 2009 Turner, J. (2005). Making the Most of Waste En ergy. Science and Technical Information- National Aeronautics pose Administration online available from http//www. sti. nasa. gov/tto/Spinoff2005/er_7. html 17 April 2009 Wang, L. , Sunden, B. , Manglik R. M. (2007). Plate Heat Exchangers Design, Applications and Performance. Southamton, Boston WIT Press