Unit lab 2

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Unit lab 2

  1. 1. DEFINITION AND TYPES OF HEAT EXCHANGER HEAT EXCHANGER Definition and Types of Heat Exchanger JOSEPH ESTURDEFINITION AND TYPES OF HEAT EXCHANGER 1ENGR. MICHAEL MANGAOANG
  2. 2. DEFINITION AND TYPES OF HEAT EXCHANGERHeat ExchangerThe general function of a heat exchanger is to transfer heat from one fluid to another.The basic component of a heat exchanger can be viewed as a tube with one fluidrunning through it and another fluid flowing by on the outside. There are thus three heattransfer operations that need to be described:Convective heat transfer from fluid to the inner wall of the tube,Conductive heat transfer through the tube wall, andConvective heat transfer from the outer tube wall to the outside fluid.Heat exchangers are typically classified according to flow arrangement and type ofconstruction. The simplest heat exchanger is one for which the hot and cold fluids movein the same or opposite directions in a concentric tube (or double-pipe) construction. Inthe parallel-flow arrangement, the hot and cold fluids enter at the same end, flow in thesame direction, and leave at the same end. In the counterflow arrangement, the fluidsenter at opposite ends, flow in opposite directions, and leave at opposite ends. DEFINITION AND TYPES OF HEAT EXCHANGER 2 ENGR. MICHAEL MANGAOANG
  3. 3. DEFINITION AND TYPES OF HEAT EXCHANGERTypes of Heat ExchangerA. Shell-and-Tube Heat Exchangers – These are exchangers that have bundles oftubes contained in ‘shells’ or pressure vessels. Like in osmosis, the fluid or gas that hasto be treated will flow through a series of tubes. Depending on the temperature of theinput, the result would be the exact opposite. For example, if the liquid on the first seriesof tubes is hot, the second group of tubes will help initiate the process of temperaturechange in order to produce cooler fluid. Perhaps the only drawback of these exchangersis the complexity of their design. Some considerations are being measured just toensure its efficiency in large-scale processes. Aside from the built, the amount ofworkload and the maintenance costs are also taken into account by most industrialengineers.B. Plate Heat Exchangers – These are units that use thin sheets of aluminuminstead of tubes. Although they basically function in the same manner as theaforementioned, these exchangers are rather more efficient in the process of heattransfer. Its structure is composed of ‘plates’ that are grouped as a stack in a frame,having gaps several inches wide so that they do not touch each other. They are usuallyheld together by gaskets, which are detachable in order to be able to access the plateseffortlessly for cleaning and tune-ups. The main advantage of plate exchangers from thetraditional shell-and-tubes is the large amount of surface area provided to allow the fasttransfer of heat. However, it is this same mechanism that these exchangers have thatcan be of a disadvantage to them. Due to the rapid expansion of fluids over the plates,leakages are likely to happen during the exchange process. They are also susceptibleto fouling or contamination because of the narrow space between the plates in whichthe liquid flows. Overall, the plate exchangers are by far the most practical devicesgiven their compactness and low maintenance costs.C. Regenerative Heat Exchangers – As the term might suggest, these exchangerspromote energy conservation. They have this design that allows a cycle of heat transfer. DEFINITION AND TYPES OF HEAT EXCHANGER 3 ENGR. MICHAEL MANGAOANG
  4. 4. DEFINITION AND TYPES OF HEAT EXCHANGERThe exchange takes place on both sides of the machinery. The exiting fluid is usedagain as an input, and the whole process of heat exchange continues as a cycle. Thistype of heat exchangers can be adopted by using either the tube bundles or plateexchangers.D. Adiabatic Wheel Heat Exchangers – The term ‘adiabatic’ pertains to thethermodynamic process that happens without any loss or gain in heat. As a heatexchanger, the adiabatic wheel acts as a mechanism for storing the heat before it iseventually released. DEFINITION AND TYPES OF HEAT EXCHANGER 4 ENGR. MICHAEL MANGAOANG

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