 Hello and welcome to understanding thermodynamics. My name is Adrian and this video will cover an introduction and overview and what content you can expect from this playlist. Let's get started. So the contents of this video will include what is thermodynamics. It will have an overview of the videos that will cover the content. And at the end, we will have a numbered list of the names of all these videos. So what is thermodynamics? Thermodynamics is the study of energy and energy conversion. And a very good example of energy conversion in real life is a power plant. Now, in the boiler, water is converted to steam by inputting energy. So heat from combustion is used to convert water to steam in a boiler for power station. And that high pressure steam is then sent to a turbine which extracts work from the turbine in the form of shaft power, shaft work. And then the low pressure steam, which is exhausted from the turbine, gets sent to the condenser where it is changed over to water. And then this water gets pressurized again through a pump and it gets sent back to the boiler where the whole process starts over again. Now, as mass flows between the subsystems in and out of the turbine, in and out of the condenser, we can say that this is an open system or these control volumes are open systems as the mass flew into and out of each one. Another system that converts energy is an internal combustion engine. Now, the energy is released on the combustion of a fuel mixture and this creates high pressure inside the piston cylinder setup which then drives the piston downwards providing work that is necessary to turn the crankshaft. You can see air is moved in, it's compressed, the mixture ignites creating high pressure that pushes the piston down and the air is exhausted. Now, the combustion process takes place when both the inlet and the outlet valve are closed. And we can thus say that this is a closed system. Now, in thermodynamics, we are also interested in the properties of the substances that we looked at and which is involved in the energy conversion process. One such property is pressure. Now, we assume that substances consist of small particles which are molecules or atoms and that these particles collide with each other and the walls of the container that it's contained in. Now, these collisions exert a pressure on the walls. Temperature is another property of a substance and if we add heat to a gas in this container, the temperature of the gas will rise. For an ideal gas, there is a relationship between pressure, temperature, and the volume of the container that this substance is in. And this relationship is given by the ideal gas law. Now, air is usually considered as an ideal gas. Another substance common to energy conversion is water and water comes in two phases, either liquid or steam. Now, for when you boil water, the temperature at which water starts boiling is dependent on the pressure where it's being heated up at. The higher the pressure, the higher the temperature at which the water boils is. Density is another important property of water that we look at. Usually, we look at the inverse of density which is specific volume. And steam is usually what we call a real gas. In other words, the ideal gas law does not apply to it. Talking about boiling water, I like to boil my water for my coffee at atmospheric pressure, please. What gets you up in the morning? Let me know in the comments below. We will also look at the first law of thermodynamics. The first law of thermodynamics states that energy cannot be created or destroyed. As mentioned already, in a power station, energy in the form of heat is released by combustion of coal or by the fission of uranium or collected from the sun. Now, the energy is flowing into the system. It has been given to the water and the water starts boiling and this creates steam which is used to drive a turbine. One of the outflows of this power station system is electricity, which is actually the power delivered by the shaft of the turbine driving the generator. Another stream out of this power station is heat which is released when the steam is condensed back to water inside the condenser. We will also look at the second law of thermodynamics. Now, the second law of thermodynamics states that it is impossible to convert all the high temperature heat into work. There will always be some waste heat and this is even true for ideal systems. Now, in an ideal system, there is no friction or turbulence that we need to take into account when we look at systems and this will usually result in maximum theoretical efficiency of our energy conversion system. Now, in real systems, there are all sorts of inefficiencies and this will reduce the actual efficiency of the system. If you look in an open fire, all the heat is lost to environment and none of it is converted into work. So as far as converting heat into work is concerned, the efficiency is zero. We use the concept of entropy when we study ideal and real processes to have a look at all these ideal and real efficiencies. Now, entropy is essentially the degree of disorder on a molecular level. The entropy of a perfect crystal, which is a solid, can be a solid, at zero Kelvin is zero. Now, as we add heat to the system, the order starts to diminish and the entropy increases as a result. Now, for an ideal process, the entropy of a system, which includes the heat source in this case, remains constant, but in a real process, the total entropy increases. In effect, we are generating entropy. So here is essentially a graphical representation of the structure of this video series. First, we will cover properties of substances, which we will look at, which is the temperature, pressure, volume, specific density and specific volume. Then we will consider energy conversion methods and this will be enclosed in open systems, such as a power station or internal combustion engine. And then lastly, we'll look at entropy and we will study the differences between ideal systems and real systems for different configurations. And here is a table of all the contents that we'll cover. You can have a look at this table or if you just look at the titles of all the videos, you'll get a good idea of the breadth and depth of this video playlist. Thank you very much for watching. The course notes that these videos are based on is on my website, AdriansBlog.com and you're more than welcome to connect with me on Twitter. My Twitter handle is at ASVN90, where if you have any questions, you're more than welcome to ask them and I will gladly answer them as well. Thank you very much for watching and I will see you in the next video. Bye.