 Sometime I talked about Mr. Sunil Dutta and Kulkarni as well as mr the content of this video session are definition of stream condenser, functions of stream condenser, advantages of using stream condenser in stream power plant, elements of stream condensing plant and their function. Now let us see what is the definition of stream condenser. Before we study the definition of stream condenser as we know that in case of stream power plant we use the ranking cycle and in the ranking cycle and four components like boiler, stream turbine, condenser and word feed pump. In case of turbine or stream engine if you want to let out the stream after expansion in the engine or turbine to the atmosphere then we can expand the stream maximum up to atmospheric pressure theoretically or practically speaking the pressure of stream should be higher than atmospheric pressure so that it can come out of the stream turbine or condenser. However if you want to expand the stream below atmospheric pressure then we need some closed vessel in which we can expand the stream below atmospheric pressure or vacuum pressure that is vacuum pressure which is called as the stream condenser. Now let us see the definition of stream condenser. Condenser is a device in which stream is converted into the water at a pressure less than atmospheric pressure. Let us think why do we get the pressure less than atmospheric pressure which we call it as a vacuum in case of stream condenser. As we know that if we compare the specific volume of dry saturated stream at atmospheric pressure and if we compare the specific volume of saturated water then there is a huge difference the specific volume of saturated water at a pressure atmospheric pressure or lower pressure than atmospheric pressure it is 0.001 meter cube per kg. It means that when the stream is converted into the liquid the specific volume is drastically reduced. It is reduced by around 1000 times less compared to the dry saturated stream specific volume and therefore there is a production of partial vacuum inside the condenser. Thus in case of condenser we can expand the stream at a pressure below atmospheric pressure or vacuum pressure. We can see the condensation can be done by removing the latent heat of the operation from the exhaust steam coming out of the turbine or steam engine using a circulating cooling water. So after removing the exhaust steam latent heat this exhaust steam gets converted into the saturated liquid in case of condenser. Actually a condenser is basically a heat exchanger in which the heat of steam is given to the circulating cooling water and steam gets condensed from vapor state to liquid state whereas the cooling water will get heated because it receives the heat from exhaust steam. Now let us see the functions of steam condenser. The first function of steam condenser is to reduce the turbine exhaust pressure or back pressure of the turbine so as to increase the specific work output. Now the question arises why the specific work output will increase. When we expand the steam from high pressure to a pressure less than atmospheric pressure there is an increase in enthalpy drop. This increase in enthalpy drop gives us the more specific work output from the turbine and since the plant efficiency is defined as the net work output divided by heat supplied, the net work output from the plant will be more when the specific work output of the turbine is more. So we get increased plant efficiency further it also gives us the advantage that the amount of steam required to produce 1 kilowatt of power will decrease. That is for same size of the plant we will require the less steam flow rate that is the specific steam consumption will decrease when we use steam condenser. Now to condense the exhaust steam from the turbine and to reuse it as a pure feed water in the boiler so when we use the steam condenser what we advantage we get is that the exhaust steam is condensed back into the water which we call it as a condensate and this condensate being pure we can reuse it again and again as a feed water in the boiler only we require to supply the make up water to compensate the loss of water if any. So with the use of condenser we are getting 2 advantages first specific work output will be more and we can reuse the condensate again and again as a boiler feed water. Now let us see the advantages of use of condensers in case of steam power plant. The first advantage that we get due to use of condenser is that we are having a higher pressure drop which results in the larger enthalpy drop. Due to this larger enthalpy drop or higher enthalpy drop we get the work output per kg of steam that is specific work output of the per kg of steam will be more in case of plant using a steam condenser and which also results in the reduction of specific steam consumption. Third advantage that we get using the steam condenser is that as condensate can be reused as a feed water to the boiler and this condensate being hot this will reduce the time of evaporation in the boiler further it will also result in the less requirement of fuel. Therefore the fuel required in case of boiler to produce the same state of steam from the initial hot condensate will be less which will cause the fuel economy or indirectly we can say that it will increase the boiler efficiency. Further because this condensate which we are reusing is a treated water no feed water treatment is required hence the cost of feed water treatment will be reduced which will also reduce the cost of plant. Further since this feed water is a treated water the problem of formation of scale deposits in the boiler can be prevented. Thus we get these advantages by use of steam condenser and steam power plant. Now let us see the various elements of steam condensing plant. Now there are totally the eight elements in steam condensing plant. First one is condenser, second is air extraction pump, then condensate extraction pump, circulating cooling water pump, hot well cooling tower, make up water pump and boiler feed pump. Now let us see how these elements are placed at what location and how what are their functions. Now just now as we have discussed the condenser is a closed vessel in which the exhaust steam from the turbine or engine will be admitted and this exhaust steam will be condensed into the liquid due to the removal of latent heat. For this steam will give the heat to the cooling water which is circulated through the tubes in the condenser. Now as the steam gets condensed in the condenser the pressure inside the condenser is reduced that is we get the pressure less than atmospheric pressure which we call it as a vacuum. So this condensate is at a pressure below atmospheric pressure. So it will not come out of the condenser on its own. Therefore we require some additional pump which we call it as a condensate extraction pump. So the function of condensate extraction pump which is placed between the condenser and hot well is that it will take the condensate at low pressure from the condenser it will increase its pressure and it will deliver it to the hot well. Now this hot well is nothing but a storage reservoir for the feed water in the form of condensate. Now from this hot well the boiler feed pump will take this condensate as a feed water it will increase its pressure to the required boiler pressure and supply it to the boiler. Now another important device which we element which is used in case of steam condensing plant is that it is the air extraction pump. The function of air extraction pump is that whenever the steam is entering into the condenser along with the steam the dissolved air enters into the condenser. Also there are other sources of leakage in case of condenser the air may leak through the joints etc. So this air has to be continuously removed with the help of air extraction pump. Otherwise it will increase the pressure in the condenser and the condensation will not take place properly. So we use the air extraction pump to maintain the required vacuum inside the condenser. Now another important circuit that we find is that if we do not have a large quantity of fresh water available for circulating inside the condenser then we require to use one of the important device which is called as the cooling tower. So what cooling tower does actually when the cooling water is circulated through the condenser tubes then it will get heated this hot water is spread into the cooling tower and due to the phenomena of evaporation and direct contact between the air and hot water this cooling water gets cooled and it is collected at the bottom of the cooling tower. This cold water again cold water again is circulated through the condenser again and again using the cooling water pump. There are certain losses during the evaporation phenomena the certain cooling water we are losing to make up that the make up water is supplied with the help of make up water pump from the nearby source available. So these are the various elements of steam condensing plant and their function. These are the references. Thank you.