Thisreport provides a detailed explanation of an air condenser that Icame into contact with during my engagement at a given manufacturingfirm. It was a shell and tube heat exchanger that is fitted onmachines so as to enable them release some of the heat that they areproducing with an aim of providing a cooling effect to such machinesand enable them to work efficiently within their prescribedcapability. The paper provides a description of condensers with anaim of introducing the reader to their general concept, purpose aswell as the different types of condensers that exist in the market aswell as their general working specifics. It after also delves intothe more specifically chosen air condenser, which is the shell andtube heat exchanger with an aim to be more specific and shed moredetails concerning the device. Quite notably, the paper provides amore detailed explanation of how the device is designed with an aimto enable the reader to appreciate the level of mechanics that hasgone into it. The design also plays a huge center stage forexplaining kind of processes that are involved while it is running.The most preferred and desirable running conditions for the devicehave been clearly indicated as well as the different types of thedevice that are existent in the market and how the one acquired bythe company defers from the others. The strengths and weaknesses ofthe condenser have been clearly outlined with an aim of forming abasis of whether the company did justice in acquiring it or morecould have been done towards the achievement of the same. It alsosheds a light on the benefits that the device has brought to theplant since it was acquired. The paper also provides an outline ofhow the device is serviced regarding timelines and the kind ofmeasures that the company takes to ensure that its work standards arewell evaluated for avoiding being caught off-guard, in case it doeshave some faults that could have been detected earlier and wellsorted out within time. The paper also contains a conclusion thatsums up the general feeling of concerning this type of an aircondenser and its working processes. About the same, it also givesout the relevant recommendations that may come in handy, especiallyif the company has an aim of acquiring the device to establish if itis a worthwhile idea or they could opt for other forms that could bemore efficient than the one indicated in this paper. It also givesout an area of application where the use of this type of aircondenser could be more feasible and able to rake in more returns forthe company interested in the idea. The analytical details providedin this paper take into consideration the designs of the aircondenser that the company acquired during my stint with them. Thepaper provides some of the recommendations that are quite vital inensuring that the air condenser used by the company is made moreefficient than it currently is. This aspect will not only aid in theproduction process but also provide the technicians in charge ofservicing the device a very ample time in the process. Itacknowledges that with the growing trend of innovation inengineering, it is highly possible that newer models of the heatexchanger could have been launched, which have a more improvedfunctionality that is quite different from the one indicated here.
AirCondensers are devices that are applied to the transfer of heatbetween fluids. These fluids could be separated by strong walls so asto prevent them from mixing or being in close contact with eachother. These air condensers are applicable in various areas, namelyair conditioning, chemical plants, petroleum refineries, spaceheating, power stations, sewage treatment, natural gas productionamong many others (Kakaç, Liu, and Pramuanjaroenkij, 2012). Oneinstance of an air condenser is the one found inside the combustionengine in which there is a circulating fluid that is used as acoolant. The fluid goes through the coils found within the engine andat the same time, air goes past the coils, thereby forms a scenariowhere the coolant is cooled, and the incoming air is well warmed up.Air condensers are classified in three ways. The classification takesinto consideration the flow arrangement of the air getting into thedevices that need to be cooled.
Oneof them is the parallel flow air condensers. This stance, two fluidsare passed through the condenser through the same entrance. Thefluids travel in a manner that is parallel to both of them. Anothertype of air condensers is that of counter-flow. As their namesuggests, the fluids used as coolants in this device are passedthrough it from opposing ends. This design is considered as the mostefficient since it capable of transferring a good percentage of theheat from the heat transfer medium. This is as a result of theaverage difference in temperature being higher along the unit lengthof the pipes (Kakaç, et. al, 2012). The third classification of aircondensers is that of cross-flow. In this stance, the fluids used ascoolants in the condenser are passed through the device in such a wayas they are in a perpendicular motion to the each other as they passthrough the condenser.
Thedesigners of air condensers have applied various measures so as toensure that the air condensers made achieve some level f efficiency.One of them is with the aim to maximize the surface area formed bythe wall that separates the fluids while at the same time aiming tominimize the resistance that could hamper the flow of the fluids asthey go through the exchanger. There are some features that arelikely to affect the performance of an air condenser. One of them isthe presence of fins as well as the availability of rust in eitherone or both sides of the condenser (Thermopedia.com, 2015). Thisaspect has a high likelihood of increasing the surface area that hasa chance of channeling the flow of the fluid and bring aboutturbulence within the fluid, thereby affecting its level ofperformance.
Thereare various types of air condensers which have distinctcharacteristics that make them different from one another. One ofthem is the shell and tube heat exchanger that forms the topic ofdiscussion in this paper. Another type of heat exchanger is that ofplate heat exchangers that are formed by many slightly separatedplates that are quite thin and have an increased surface area as wellas quite small passages to permit the flow of fluids through them.These features are incorporated into this type of condenser so as toenable it ensure that the transfer of heat is up to its optimum.Another type of an air condenser is the of plate and shell exchanger.This type of an exchanger combines the designs of the plate heatexchanger and that of the shell and tube exchanger to come up withtechnology that can perform effectively under a given circumstance.Another type of heat exchangers is known as the Adiabatic wheel heatexchanger (Serth, Lestina, and Ebooks Corporation, 2014). This typeof a condenser applies the use of a solid store or an intermediatefluid so as to hold on to heat. This fluid or the solid store thenmoves to the other end of the heat exchanger so as to enable it to beremoved from the system and take away heat from the device in theprocess.
Thereare many other types of air condensers available in the market, eachhaving various conditions that enable them to perform their variousduties and function effectively. It is pertinent to take intoconsideration the fact that not these condensers may need to becustomized, where needed, so as to meet the various specificationsthat different users may require and enable them to reap maximumoutput from investing in such kind of condensers.
Thesweets and candy manufacturing company that I was attached to made apurchase of a new shell and tube exchanger that was used to provide acooling mechanism for its shrink wrapping machines and prevent themfrom suffering the negative effects that are brought upon by thecircumstance of overheating on machines (Serth, et. al, 2014).Because the shrink wrapping machines were quite distinct to theoperations that the company was involved in, it required the companyto acquire a customized condenser that could be easily fitted on tothe machines and work best at the set conditions that wereestablished. The working principles and the design of the device havebeen clearly indicated in the following sub-topic.
Designfunction and process
Theshell and tube heat exchanger are composed of tubes that run parallelto one another. One of the tubes has a fluid that either needs to beheated or cooled. It is such a principle that comes in handy andhelps to ensure that that the process of cooling that is carried outby the air condenser is quite effective and runs smoothly. The set oftubes also has a fluid that runs over them so that it may either coolor provide heating over them. This set of tubes can be made of tubesthat are either longitudinally finned or plain (Hcheattransfer.com,2015). These types of condensers are normally used in cases wherepressures are quite high with temperatures being higher than 2600 Cand pressure being above the 30 bar. One feature that makes thissituation feasible is the fact that these are evidenced in thisinstance. There are various features that are put into considerationwhen coming up with the thermal designs. One of them is the fact thatthe margins of each tube need to be connected to holes that areperforated in tube sheets. The tubes may either be bent so as toresemble the shape U and be known as U-tubes or could be straight innature. There are some of the features that were incorporated intothe air condenser device so as to make it quite practicable and in agood position to provide the kind of benefits and workabilityintended.
Onewas them was the fact that the diameter of the tubes found within thetube and shell air condenser was quite small so as to make it compactand economical. While this was quite advantageous for the operationsof the plant, it provided a challenge in that the condenser had ahigh likelihood of having mishaps quite faster owing to the smallspaces between the tubes. The small size also brought a problem inthe cleaning of the device, increasing the chances of it havingvarious mechanical problems. This situation meant that the devicerequired frequent servicing (Ananthanarayanan, 2013). . The tubesused in the condenser were also thick so as to provide an allowancefor corrosion. It also helped to provide the tensile strength thatwas required for the tubes and as well, enable the tubes the internalpressure that was brought about by the flow of various fluids withinit. The tubes within the condensers were, however, short so as toprovide ample space for installation. The fact that the tubes wereshort meant that the company had to pay more for the condensers,since, apparently, it is quite a costly t make condensers withshorter tubes as opposed to making ones that have longer tubes. Thefact that the tubes were quite short was also significant as itensured that it was possible to replace them in case some of themdeveloped faults and needed t, be replaced. This is because longtubes are quite difficult to take out and replace.
Thetube pitch, which is the middle-centre distance of the tubes linkingup, of the condensers was approximately 1.27 times that of theoutside diameter. As a result, the overall diameter of the shell wasa bit less, which led to a reduction in the cost of making the aircondenser. The tubes inside the condenser are arranged to give atriangular pattern that bears an angle of 300. This pattern was quitecrucial for the device as it enabled it to provide an efficient heattransfer. This is because they enable the fluid to flow in a moreefficient manner around the piping system. The condenser was alsomade in a baffle design that helps in directing the fluid to flowthrough the tube bundle. The baffles are perpendicular to the shelland help to hold the bundle. The design of the baffles helps toprevent the tubes from sagging across their long arms (Serth, et. al,2014). This also prevents the tubes from vibrating and causing aproblem to the tensile strength of the structures. The segmentalbaffles of the air condenser are also placed in an 1800 angle to thenearer baffles. This situation forces the fluid to flow downwards andupwards. The baffle within the air condenser was also spaced outclosely in such a way so as to create a great drop in the pressure asa result of the redirection of the flow of the fluid.
Thetubes inside the air condenser were made of the material that wasable to farther an apt thermal conductivity. The air conditionerfunctioned in such a way that two fluids that have differenttemperatures flow through the tubes found within the device fromdifferent ends. This situation ensures that heat gets transferredfrom the fluid located on one side of the tubes to the other acrossthe walls of the tubes. The baffles found within the air conditionerhelp to ensure that air is directed through the sides of the shelland does not take a short cut since this will result in an effectiveflow volume.
Theshell and tube heat exchanger applied to the plant are also importantin ensuring that the level of cooling applied to the shrink wrappingmaterials. The device is highly preferred because it is quite easy toservice, especially since the model has a tube bundle that isfloating. It was also easy to install since the tubes inside thedevice were quite short, therefore, providing an easy platform forensuring that it was well installed to the shrink wrapping machines.The aspect of acquiring the device with short tubes, however, meantthat the company would have to pay much more since they are morecostly to create compared to those with long tubes (Serth, et. al,2014). The walls of the tubes were also thick, which enabled thetubes inside the shell and tube air condenser to withstand thepressure that was provided by the fluid that flowed within them.Another advantage provided by the devices is the fact they provide alarge surface area that ensures that the processes of cooling arehighly expedited. Since the device applies the principle ofcounter-current flow of air, it provides an advantage of ensuringthat the highest achievable log mean temperature difference isachieved between the two fluids of varying temperatures. The metalmaterial that made the tubes of the air conditioner devices were alsocompatible with the side fluids and the shell for long periods oftime.
Thishelped to ensure that they were not subject to corrosion anddeterioration that would take place as a result of coming intocontact with fluid that flows through them. The tube materials werecarefully selected. So as to ensure that it met the requiredcriteria. The material is also chosen in such a way that they preventany form of leaks between the tube sides and the shell. The heatexchanger provided a challenge in that it needed regular servicingbecause clogging took place because the internal diameter of thepipes was quite small. It also presented a great challenge regardingcleaning it since it was quite hard to access the internal parts ofthe tubes. Another challenge that was presented by the airconditioner was the fact that the channel used in them was not abonnet (Kakaç, et. al, 2012). A bonnet is usually preferred becauseit is fitted in services that do not require one to remove thechannel frequently so as to effect cleaning and inspection. This isbecause This form of air condenser is not as effective as the plateand shell air condenser. However, the management of the plant optedfor such kind of a condenser since it is quite cheaper to obtain andas well, the cost of maintaining such a condenser is much lowercompared to the latter.
Forthe entire period that the shell and tube heat air condenser was inoperation, it was serviced for about four times. This was due to theform of clogging that took place as tubes had a small diameter thatincreases the chances of particles filling up the inside of themetals. The air condenser bears its fair of challenges within theplant. However, bearing in mind the kind of applicability that it hasas well as the specifications that it is required to meet, it isstill the best option that the management of the company could havesettled on at the time of obtaining the device (Kakaç, et. al,2012). Amidst all the issues that are associated with the device, theadvantages far outweigh the disadvantages that it bears. One of suchadvantages includes the fact that the company obtained a tube heatair condenser that was quite easy to install since its tubes whilequite a shorter. It is quite expected that the company is on thelook-out for any newer model of the device that could be out and posemuch greater benefits other than the ones suggested in this paper. Itis my firm faith that the management shall take a consideration ofsuch actions.
Soas to ensure that the plant buys an air condenser that has a highpotential of bringing in more benefits and is quite cost-effective,it is pertinent for it to go for a more customized device. One ofsuch elements could be that of combining the specifications of thismodel to that of another so as to come up with one that equally lesscostly but at the same time, capable of carrying out the requiredfunctionalities with the least mishaps possible. So as to minimizethe problem of clogging and need for regular servicing of the tubeswithin the shell and tube heat air condenser, the designers may needto settle for tubes that have a slightly larger diameter while stillbearing the ability to enhance its level of functionality. Thecompany may also need to settle for much newer models of thecondenser that are available in the market that could be quitedifferent from the one that it is currently operating. There arevarious specifications and additions that could be added to the newermodels of the air condenser so as to make it more efficient. One ofthem is such as the addition of a bonnet that could assist increating ease and reducing the need for opening and closing thedevice most of the time so as to make any form repairs and servicingon the machine. It is this form of opening and closing that bears agreat potential for spoiling the machine and reducing its chances ofremaining durable for a long period. With the application of therecommendations suggested in this paper, it is expected that themanufacturing company will be in a good position to obtain a devicethat shall act much to its benefit.
Ananthanarayanan,P. N. (2013). Basicrefrigeration and air conditioning.New Delhi: McGraw-Hill Education (India.
Hcheattransfer.com,(2015). Shelland Tube Heat Exchangers Construction Details.Retrieved 14 December 2015, fromhttp://www.hcheattransfer.com/shell_and_tube.html
Thermopedia.com,(2015). A-ZIndex.Retrieved 14 December 2015, fromhttp://www.thermopedia.com/content/1121/
Kakaç,S., Liu H., Pramuanjaroenkij, A. (2012).HeatExchangers: Selection, Rating, and Thermal Design, Third Edition
Serth,R. W., Lestina, T. G., & Ebooks Corporation. (2014). Processheat transfer: Principles and applications.Amsterdam: Elsevier/Academic Press.