Lecture 21 : Energy Transformations

[Music] good afternoon everyone welcome to yet another lecture of uh the NP Ms course titled carbon accounting and sustainable design in product life cycle management so uh this course is offered as part of the nbal MS course uh which is offered from I kpur and I'm Dr deu Philip and along with me Dr pral pradap Singh and Dr amand Singh ooy are caught teaching this course and uh I been doing the first part of this course and uh we will get to the this today's lecture is somewhat the concluding lecture of the first section of the course and today's our topic is the energy transformation so many of us are been or there are so many questions about energy transformation uh in the Forum so we are going to answer one by one so let us talk about energy forms first and some of the common premises in which uh the energy and the calculations and other things have come up with so for us the energy is defined as the energy is the ability to do work to do work is the very simplest way of looking at it and that's what we do and there are different sources of energy okay we know that right and so what happens is then transformation of energy from one form to another okay so he energy to electricity or motion Etc like that okay mechanical energy we had already seen that we studied in various courses right we also differentiate which other faculty members uh will teach in this course will talk about differentiate between renewable energy nonrenewable energy and inexhaustible energy okay so these three three forms of energy will have its own uh okay it is um uh they are treated differently okay so the other part is that what are the main uses of energy we are concerned with many people said there is no limit to what usages energy is concerned but in our case we are talking about the main uses will be Transportation okay then uh Heating and Cooling okay uh powering systems uh we also talk about transformation process okay operational Etc okay so the many uses there are like sometimes we may not be worried much about uh you know charging one mobile phone but we may be definitely be worried about how much it would require to charge uh country the mobile phone of all the people in the country so that kind of a thing so we probably would be in the remaining models of this course we will be looking at the larger usages of energy and when we talk about energy transformation okay it is the process of process of changing one form of energy to another okay and most of the time it is uh heat to Mechanical to electricity okay then electricity to heat okay or cold whatever it is okay uh or thermal we can call heat also you can think about as thermal yeah thermal energy you can think about us uh potential energy uh potential energy to uh mechanical to electricity Etc okay these are all different ways of con transformation of energy from one source to another okay so we had discussed this concept in many places and then people add this question about biomass and then transformations so let us talk about that so one way to think about is trees and plants absorb sun's energy and store US Chemical energy through uh the photosynthesis process so what they do is they use uh sunlight water and nutrients from the soil and uh they absorb the carbon and then fix the carbon and release oxygen so they use so if you think about it it is the inputs are the inputs are sunlight water carbon dioxide okay uh nutrients okay outputs oxygen starch uh or fructose Etc okay and the hydrogen gets stored in the uh so in another way to think about it is this is also in another way of replenishing the oxygen in the atmosphere okay now these where do you store this chemical energy it is basically stored in the stem of the plant or the fruits of the plant so when wood from tree from trees is burned when you burn the wood from the trees when the wood from the trees is burned heat and light energy is released or are released uh as and when the chemical bonds chemical bonds are broken so asan when you break the chemical bonds okay this chemical energy that is stored in this when those bonds are breaken or broken those uh uh that breaking happens through the process of burning then that happens heat we emit heat and light energy but along with this we also release so the burning releases carbon dioxide and other gases okay so that's also the disadvantage of the burning process now if you you look at the word biomass okay what does biomass means it is the total quantity total quantity or weight uh of organisms in a given area in a given area area okay for a given area for a particular area it is the quantity or weight of the organisms this includes plants and animals okay both okay so it's a total quantity that's called as the biomass all right now we mentioned animals so how do animals get into this picture so animals eat plants okay animals eat plants uh and dung is produced like cow dung is produced which when burned when you burn it releases heat and some light energy okay so the animals eat the plants then they produ refuse or dung and when you burn that dung then uh it releases heat and some light energy so that's how the animals also become part of this biomass cycle okay then one more thing is that dead plants and animals gradually rot rot and over millions of years are compressed in Earth's crust uh to form or to become fossil fuels okay so the dead plants and animals they gradually rot and over millions of years the compression the pressure that is applied on the Earth's crust that becomes fossil fuels fossil fuels includes crude oil coal natural gas Etc okay these are all part of the um uh the uh the biomass and the energy transformation so now let's talk about the forms of energy okay which are relevant to this uh course in this case and uh many of the discussions you have seen we have talked about Sun atmosphere Earth carbon cycle all those kind of things so sun is the prim primary source energy source primary energy source uh for most for most of for most situations okay uh where we require energy for our daily activities so sun is the primary energy source okay uh for most of the situations uh where we require energy for our daily activities Sun so primary source of energy is Sun okay however other forms of energy forms of energy exists exist that do not involve Sun okay there are other forms of energy so couple examples not too much okay number one is geothermal number two is nuclear number three is hydroelectric in my opinion hydroelectric even though people say that it doesn't involve Sun but although uh sun does power the water cycle uh that drives the hydroelectricity so what is the water cycle okay in this regard if you think about it this is the ocean um and uh we assume that here is Sun okay so the the water this is evaporation okay and it forms clouds okay clouds go to Mountain okay so you have rain this is mountain and then this water flows okay and this is a river and you have a dam that stops the flow of the river it goes back into the ocean but then from here you have a uh yeah you have a Powerhouse where this water is used to generate electricity so this cycle this you operation and uh formation of clouds is driven by Sun so hence you can say that the hydroelectricity sun does play some part so let's talk about this geothermal nuclear and hydroelectric quickly so that uh we can conclude this topic okay so number one in volcanic areas Molton molten rocks Heat the groundw okay so in wherever active volcanos are there the molten rock okay it's also the lava that heats the groundw okay which Rises to the uh surface uh surface as hot water and steam okay so if you have hot water and steam then you can use okay then we say this steam is used to uh rotate uh turbine and um generator the generator is coupled to the turbine electricity is produced okay I would request you guys is example read about Iceland okay where they use a lot of geothermal energy okay then uh nuclear fuels like uranium uranium dry the nuclear power okay we have read about this okay so what happens is okay uranium causes chain reaction action in nuclear reactor react ctor this uh produce L large quantity of heat okay it boils the water and produce steam the steam drives a turbine that has a generator that produces electricity okay so this is the uh logic by which the nuclear energy is produced as part of everybody knows uh about this but I just was giving you a Qui recap because there are some questions in the uh so hydroelectricity is generated by Hydro power okay so what is hydrop power okay so hydrop power is the gravitational force of falling or for flowing water okay so the water is Flowing so you have use a dam stops the water and then you make it flow from a height so you know that uh potential energy is okay so potential energy is M GH H is the height okay uh transformed to to kinetic energy half MV squ right so if you have high you stop water at a very high rate that height will translate to the velocity okay so that velocity will go and then uh run the turbine okay the flowing water will run a turbine turbine uh or hit an impeller and that impeller will drive a turbine turbine will drive a generator and produce electricity okay okay Hydro power is the uh most widely used used form of renewable energy solar comes only after that okay uh it is renewable because why it is renewable a uh produces no direct waste okay B minimal ghg greenhouse gases compared to to fossil fuel plants okay it does not produce any direct waste and minimal GH ghgs greenhouse gases in comparison to fossil fuel plants fossil fuel includes coal NAFTA that kind of a plants so with this we come to the end of this lecture uh which actually gives you a quick idea about energy energy transformation and uh the forms of energy specifically other than Sun uh which is uh uh hyal Power Nuclear clear and geothermal and also we discussed what is biomass and how biomass acts in this whole business and what is water cycle as well so these things are uh will be used in the coming sessions when you building uh models energy models and uh estimating carbon Footprints Etc so I will see you sometime later down the course with the some more additional topics based on the request that is coming from the uh audience until that time um please continue to read uh the content and materials and uh enjoy learning thank you very much [Music] [Music] [Music]