Steam and Gas Power Systems Prof. Ravi Kumar Department of Mechanical and Industrial Engineering Indian Institute of Technology - Roorkee Module No # 01 Lecture No # 01 Review of Thermodynamics I welcome you all in this course on this team and gas power systems and today we will start with the review of thermodynamics. The topic to be covered in this course are basic term in thermodynamics processes. (Refer Slide Time: 00:37) Laws of thermodynamics now there are certain basic terms in the thermodynamics which we are supposed to understand before we start with this course. (Refer Slide Time: 00:52)
The first system in thermodynamics if prescribed a region of space or finite quantity of matter surrounded by an envelope called that is the boundary. And the system is the three types of systems. (Refer Slide Time: 01:04) One is closed system second is open system and third one is isolated system. So system is prescribed region of space is it can be a physical entity or it can be an imaginary volume in the space on which the thermodynamics studies are concentrated. In close system for example this room this room can be considered as a closed system if we seal all the doors and windows of this room.
Then in this room heat transmission can take place through the ceiling or the wall or the floor of the room but transfer cannot take place. So in a close system mass transfer is not possible but heat transfer is possible now second type of system is open system in mass system and heat transfer both are allowed. For example if I open the doors and windows of this room then air can come into the room and air can leave the room also and heat transmission through the walls and the ceiling and the floor of room can take place then this room becomes an open system. Now third type of system is isolated system means there is no mass transfer and there is no heat transfer that is possible if I insolate all walls of this room and floor of this room close all the windows. In that case there will not be any heat transmission from the surroundings and room will become an isolated entity. Now surroundings anything outside the system is surrounding so anything entire universe outside this room is surrounding and system and surrounding together they make universe. (Refer Slide Time: 03:11) Now state unique condition of the system at an instant of time described by its properties. So state of the system can be described by the properties and minimum two properties are required to describe the system okay and. So state can be defined with the help of two properties. (Refer Slide Time: 03:34)
Now process suppose system is moving from state 1 to state 2 right and it moving from state 1 and state 2 it passes through in number of state now combinations of this number of states together will form a process let us say process 1 to 2 + cycle. A cycle thermodynamic cycle can be defined as there is a combination of a cycle is the combination of thermodynamic processes let us say from state 1 to state 2, state 2 to state 3, state 3 to state 4, state 4 to state 5 and state 5 to state 1. So final state of the last process an initial state of first process if they are same then this is called a thermodynamic cycle in thermodynamics there are two things heat and work. (Refer Slide Time: 04:32)