Applications of Heat Exchangers
Hello every one welcome back to the second class of heat exchangers fundamentals and design analysis. In the first class we have got some idea regarding heat exchangers and we also tried to see that how the concept of heat exchangers evolved in the very dawn of civilization when people have invented fire and started learning cooking so that is what we have seen and then of course over the years there have been a lot of change and heat exchanger has now become such an important industrial equipment. So we will see more of it in this present lecture we want to see the application of heat exchanger we have to understand why we should study heat exchanger what is its importance and that's why I like to give some application of heat exchanger to you and then we probably towards the end of this particular lecture we will try to see how heat exchangers can be classified. Heat exchangers serve different purposes but if I see that what are the main purposes served by heat exchanger firstpoint is control of temperature for process requirement and product quality let me let me explain it a little bit. that it is like this that temperature control is important for many cases for the for that matter where I am delivering this lecture this room is air conditioned so in this room the temperature of the room is maintained within certain level so that the person who will be occupying this room they will feel comfortable. Similarly suppose we are making some sort of metallurgical product and either it has to be heated or cooled because we need certain attribute of the product certain property of the temperature control is very important and heat exchanger often plays a very important role in controlling temperature. Then comes on your conservation of energy in this also the conversion of energy should be included that when we have some sort of energy conversion process heat exchanger is essential examples are many but if we think of that how we’re generating most of the most of the power in this in this in the modern age it is being generated from fossil fuel source that means the chemical energy is converted into thermal energy and then from the thermal energy we are getting mechanical energy or electrical energy. Should chemical energy that is getting converted into thermal energy some sort of combustion processes and we will see at each and every step we have got a number of viriaties think of how many different varieties of it if you can you can expect to see it is better to give some time and think that how many different varieties of heat exchanger you may expect in a product. Then protection of the environment goes hand-in-hand conversion of energy in cases it is essential to use a heat exchanger but during the conversion what we do we waste a good amount and we waste also energy in different form using heat exchanger these can be reduced these waste candy and reduction of any waste in again so when we are stopping deluxe the waste or reducing the waste of thermal energy so what we are doing we are protecting the environment from that they are a direct action by which environment can be protected and obviously he texted that plays every all the aspects why it is what it is or what is the purpose of using it. Accordingly the application of heat exchangers can be identified in three broad categories there could be controversy people may say that there are other ideas but what we think are important that is in the industrial sector that is the main use of heat exchanger many varieties of heat exchanger will be used and theen health services there will be large number of heat exchangers and in domestic in our day-to-day life we need heat exchanger for our comfort for some unique processing for our survival so we need heat exchanger. Obviously going out of survival the room heating the importance of room heating in cold countries in arctic region nobody can deny so it is not some sort of a luxury it becomes then the essential step for surviving one essential step for surviving There are different types of heat exchangers and we will see slowly what are the different type of different kind of demand. This could be fossil fuel power like your coal or oil or it could be it could be nueclear it could be renewable there will be large number of very unique heat exchangers. Refrigeration air conditioning all the implication in a grade any plan is so much dependent on heat exchanger that I mean a plant cannot all be designed properly or rather cannot operate properly unless we have designed and selected you texting it correctly and operated them very active. Petroleum refinery petroleum refinery and petrochemicals chemical process industries these are the main places for a number of detective some of the changes which has been involved for this type of processor requirement on the so again this is one important use of heat exchangers metallurgy and material processing I have already mentioned that some sort of material property that we can get only by some temperature control again is very is very important and that can be done with the help of electronic components I have mentioned somewhere but this has become very very for the next generation of computer Chanel power we can avoid these only by a good thermal management of electronic components and that can be done and obviously industrial components electronic component cooling needed not only for competition but also for other purposes and for that good is it there are many other topics which mentioned under the industrial application but I like to impress upon by showing the Oscars of heat exchanger range is this range could be many that means the temperature in it is there could be from karijini temperature to high temperature and the size it covers the material rain in corpus starting from graphite or ceramic to paper but here I just like to impress upon you regarding the size it is show on the left-hand side there is a chemical symbol cooler you can see The dimension of most important dimension something give me all are in the all are in the range of inch excetera so you can imagine that what could be the size of a circular which is nothing but it is on the right hand side okay left hand side there is there that that is an indirect contact maybe more gas and liquid component here on the right hand side we have got a hybrid couldn’t now Webley the next visible 3rd law of cooling tower which are there in apartment which is essential to your boyfriend so why it is so prominent because of its size so that you can have some idea to hear what is soul a hybrid cooling tower which is a combination of force draught and induced draught sorry for slapping natural crap so what one can find so this is actually is not a finished one so here they are a number of fans will come and this this this hydrosteam lehigh provide some sort of natural drop this is not finished one but you can see the size comparing the new dimension has been giving but here’s some people and cars are visible so you can see you can have some Imogen some imagination that what could be the size of the is there is so much there is so much variation in size of a heat exchanger very small to be obviously you can understand that what is the challenge in designing or analysing Instagram we are seeing one very small indirect heat exchanger right hand side we are seeing a very large heat exchanger which is a direct contact iFit exchanger and construction material left hand side if you see it is metal right hand side it is concrete and again we will see that this cooling tower if we discuss if we get time to discuss all this thing’s we will find that if it depends or it is a combined equipment for the transfer and mass transfer there are many things which are very important an interesting discussion application it’s service application there could be many things I have just name a few heart lung machine for cardiac surgery for dialysis the system mechanical system which is used that needs heat exchanger preservation of cell tissues blood sister we have to create low temperature without heat exchanger that is not possible then I see you I see you in some sort of a condition temperature condition is very important and then in cute babies are born before their scheduled a visit in some artificial environments in which climate and for that they are arc incubator temperature controller is very important in over continuous monitoring of temperature is very important to think of some treatment latest think of some treatment for hypothermia hypothermia and hyperthermia easy method of cancer treatment timber treatment of tumor is cancerous and they are we need high temperature and obviously in the total mechanical system click on it and then try surgeon here by ultra-low temperature we are doing some shopping list and also we need to have this kind of a system.
I just one example I have shown here this is the psychic for cardiopulmonary bypass surgery and you can see that there are different components but there is one in texting yet there is one heat exchanger there is one heat exchanger over here and actually the blood is to be heated or cooled depending on because this is how did body temperature of the patient that can be also control and that’s why we need a very good evening kind of pictures so I can I can remind the engineers who item item remind me in India’s who are involved in the design of heat exchanger the great responsibility with lines on their shoulder starting from industrial requirement where we have to be really cautious that we should not waste the precious energy which we are getting from fossil fuel we should not degrade the environment in which we are leaving and who the life of a patient that is also dependent on heat exchanger how it should be designed so that it can get to be me it can satisfy the need of such a caring nature it can be maintained properly it get me of low-cost it can be of high reliability so all these are attributes and will this kind of variety of applications are there then you can understand the challenge so let’s proceed in domestic let's proceed in domestic application of course compared to industrial needle exchange and that is less but that is not less important to come out and at some point I have told that that is also some sort of life-saving device in cold countries are very hot countries so the human comfort or human livability has to be has to be satisfied that we did Dubai air conditioning room eating basically hvac and doctor then cooking it is difficult to get household where there is there is no refrigerator so obviously we had to help design our analytics one cooking device is shown in this diagram this is a testing so basically what we do for cooking certain food we need uniform temperature and we need some control temperature so it cannot be put on direct sale so here we can see there are two parts in the external 4/4 there is water water will boil and it will maintain a certain temperature let’s say it will make it her degree celsius then the food that will be inside surrounded by his boiling water so full time you will have a lot of again a liquid etc so basically this is heat transfer between two liquids through this wall so if this is kind of a special indirect heat exchanger so you can understand how what Saturday is this component that is it time regulation is one of the prime requirements of higher animals higher animals they try to maintain the same temperature of the body irrespective of our level of activity because we know that for higher level of activity we need higher amount of metabolic energy production in the body that should also be but which has to be dissipated from the body that does not depend solely on the Sony on living being but also it depends on the environment condition because you is proportional to Delta t and this environment condition environmental condition and temperature is a lot think of the desert region where is the temperature could be close to the Arctic region where it is several degrees below the freezing point and a human being has to maintain a constant temperature constant body temperature in all this so how it is done there are very large number of there are very large number basically using these mechanisms not only hired animals mammals etc they maintain their body temperature in our body is compared to a 18in but it is not told that our body is a perfect thermostat to make it function as the perfect thermostat which will which will which will operate if the body has a constant temperature many mechanisms are letting it sit like this is not the place to discuss all this thing but counter-current heat exchange as it is done in heat exchanger that is also one of the principal this is usually done by exchanging it between arterial and venous blood flowing in opposite direction with the temperature difference and these blogs the past is to develop a type of structure so two streams are there and these claims are having temperature difference but the nature has understood in its own way that if the flow in opposite direction large amount of heat or thermal transfer or heat can be transferred in more effectively so there are many examples for cold-weather let me give you an example reindeer they are amazed with the temperature low temperature but suppose there is some sort of a condition in which they have to survive the outside temperature is high on your body is generating more into some sort of action so what happens the brain that is very vulnerable because the temperature of the brain it should be maintained and it should be bent in slightly below the other temperature several degrees below the other temperature of the phone so what is done here and see this is the arterial blood which is coming it will also go to the brain and it is going to the brain and this is the penis plant which is returning back now when it is returning back part of it goes to the nozzle region of the reindeer where there is cooling of blood due to some sort of respiration that is taken here which is called karaoke if that is basically a typical structure where the formula doing the inside and there will be very small number of vessels called blood will be passing through this so the blood on blood before going to the brain because it could and the principal is exactly similar to things are there it is similar to contact currently texting and again as I compared to increase the exchange area so the concept of complicated changing not only came to the father and of human it is also some invention of nature from its own experience this is for cooling implant sometimes for eating the plan this is needed so there are many bugs who are in the arctic region and their there had to be protected from frostbite so they are the blog is to be heated not to be good for the body part is to be heated and that is done again by similar type of arrangement by counter-current heat exchange between the two strings of plant now we go to the classification of heat exchanger this again I have mentioned here in the souls that I have taken it from the design of artesia sorry from the book fundamentals of kitenge design by artesia and artesia and basically this is one of the very important book time to time we will refer this book and this reference has also been given for the course that as a textbook classification of different categories classification classification and this is what we like to hear classification according to transfer process this is very important that we are doing the classification is indirect indirect contact that means they're not touching each other kissing each other OK they are not mixing with each other and most probably heat exchanger out of this category already I had mentioned it so what could be the different heat exchanger in this category direct transfer type that means single phase and multiples multiples means you’re boiling and condensation will take this and storage and storage what is direct transfer tape directly from one screen to another extreme it is getting transfer of course in between there is a solid phase solid wall so this is director so there is no story of it and it could be single phase that means to fluid they are in the either both of them they’re not changing their face or one of them are in some very rare situation both of them are changing their condensation boiling etcetera that is your face then stories time for this also I have explained that once Kreme is giving thermal energy to some sort of a intermediate medium-well temporarily thermal energy is getting store and then that stored energy is transferred to the other two so that is your storage then your realise that Sophia is back probably next class I will show some some figure of this text so there will be particularly and particulate solid through particularly as he’s passing so there will be certain amount of energy exchange between the particles solid and the gas and then the particulate solids to articulate solid to calculate solar system so there will be certain amount of energy exchange between the particulate solid and the gas and the game from the particulate solids to another to it which was to some sort of this is typical kind of heat exchanger in these cases to heating to heat exchanging fruits or mixing with indirect contact then we have the fire which teams are coming in contact with each other there are limitations or not all the heat exchanger can be designed like this if there are two liquid streams which animal we can go for direct contact type of it is one of them is dead and another is liquid we can go for direct contact with him and let's a liquid and a pillar system and what are we want to exchange between then so we can have again direct contact with three possibilitie we can have direct contact important lesson number in power generation and other places we find that there are direct contact type exchanger and for the obvious advantage we use direct contact exchanger. There are other classification we will take up them in our next class and from this classification also we will try to elaborate certain things in our next class. Upto this let us end the present class again I will request you, if you have got any queries please interact in the forum and we will try to clarify it.
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