Introduction
A Carnot engine works the same as a heat engine but the only difference between the two is that a Carnot engine works on a Carnot cycle. The first model was presented in 1824 by Nicolas Leonard and after that, some changes were made eventually. One such example is that the Carnot engine was Graphically expanded by Benoit paul in 1834. And afterward, also, this model was evaluated by many such people in 1857, like the one who was evaluated by Rudolf Clausius.
The Carnot engine is the most efficient model and so the efficiency depends upon the absolute temperatures of both hot and cold heat reservoirs.
What is Carnot Engine
Carnot's word has derived from the one who has proposed this model.
The model has been presented by Leonard Carnot. Carnot engine is a thermodynamic cycle that focuses on gaining maximum efficiency. The process is done at the time when the heat is converted into mechanical work between the two reservoirs.
The process takes place when the heat energy is transformed from a warm region to a cold region. The whole process was focused on converting some of the heat energy into mechanical work.
What is Carnot Engine
A thermodynamic system works on a system that works on a loop basis. It acts as a cycle, repeats the same, and finally back to the starting point. It takes a series of different states in action, that is the reason why it is called a Carnot engine.
Working Principle of Carnot Engine
The irreversible heat energy of the heat engine lies between the two reservoirs.
In this process, the energy of two reservoirs has a lower value than that of the reversible efficiency of a Carnot Engine. That is why the engine’s efficiency is operated between the two reservoirs.
All of the reversible heat engines work between the two reservoirs.
The two reservoirs should have the same efficiency for the process to take place.
In this, the temperature needs to be high to raise the thermal efficiency because the combustion chambers can do their work effectively.
Let's take an example that can explain the process quite well, is that the turbine blades are efficient in avoiding the hot gasses from the system.
And that is the reason, why this leads to fatigue in the process in the premature stage.
One of the main ideas, which is to be noted, is the same efficiency of two reservoirs. Which leads to the completion of the process.
Process of Carnot Cycle
The process of the Carnot cycle involves four stages.
Process of Carnot Cycle
Isothermal Expansion
Isothermal is made up of two words, ‘iso’ means ‘same’ and ‘thermal’ means ‘heat’. So the whole word denotes ‘no change in temperature’. From the picture above, we can analyze that there were two lines, line A and line B, which are representing the whole Isothermal process. In this process, isothermal expansion, the gas expands by moving the pistol in the work surroundings.
Adiabatic Expansion
In this step, the line focuses on the (B to C) part. In this step, we have to assume that the cylinder and pistons need to be isolated. If we talk about this in detail, then we can say that there would be no changes in heat in the whole process. The reason behind this, is that there will be no space where the heat can enter and can exit from the system.
During this process, the gas will continuously expand and so does the pressure drops, volume will increase as a result. The reason behind this is that there should be some amount of energy that comes from the inside and that will be lost whenever a similar kind of work is done.
Isothermal Compression
This kind of step takes a very different approach to focus on. The process performs the work on the gas. By that, the heat is transferred from the system to the reservoir. The main criteria should be to have the same temperature.
And when the volume of gas will increase it will automatically result in decreases in the volume of gas. The process forces the heat energy to move from the system to the cold reservoir as a result the system’s entropy will drop.
Adiabatic Compression
This step focuses on lines (D to A) which are representing the adiabatic compression. During this process, the piston and the cylinder ( the main criteria for the system to function) need to be in an isolated position while the rest of the hot reservoir can be eliminated.
In this process, the environment plays a major role to perform and is that the environment has to continually have to perform the work on the gas so that it can move the piston in whichever direction it wants.
Carnot Theorem
Carnot Theorem
The first thing which needs to be noted in the Carnot theorem is that all the reversible heat engines that are working between the two reservoirs should have the same productivity.
The reversible heat engine needs to have higher productivity than the other
In the case of irreversible heat, engines have low productivity.
There needs to be the maximum efficiency of the Carnot engine.
The efficiency is not the same for everyone.
The changes in the efficiency can happen and the reason for the same is the differences in the temperatures.
The differences in the cold and the hot reservoir lead to a change in inefficiency.
Here, the working fluid doesn't have any role to be played in this.
Efficiency of Carnot Engine
The Carnot engine denotes achieving the maximum thermal efficiency according to the second law of thermodynamics. This law was introduced in 1824. The person who introduced this law is Sadi Carnot. The idea behind is to maximize the efficiency of a heat engine. A big advantage of the Carnot cycle is that a Carnot engine can achieve an efficiency of 100 percent. The 100 percent efficiency can be attained when the temperature is zero in the cold sink. But the biggest problem is that this is not practically possible.
Components of Carnot Engine
Components of Carnot Engine
Source
It is the first component in the Carnot engine. It is a hot body-like system that works at a constant temperature. The function of this component is to deliver the heat to the working system. The source provides an unlimited heat volume. A major factor in this is that you can withdraw the heat.
2. Sink
The sink works at a low temperature because it has a low - temperature body. But the main advantage of this component is that it has unlimited heat capacity. This means that when the heat is supplied to the sink, it does not raise or neglect the temperature.
3. Cylinder
The cylinder works on a conductive and non - conductive wall. The cylinder usually comes in non - conductive pistons. They are frictionless completely. The function of this component is that the piston moves up and down to move the gas compression.
4. Insulating stand
The purpose of this component is to stand on an adiabatic operation. It stands straight and this component of the Carnot engine is made up from non - conducting material.
5. Piston
The piston is a component that is usually present inside the system. It lies inside the cylinder of a system. The idea is to cause the expansion and the compression of the gas.
Limitations of the Carnot Cycle
This type of cycle was not easy to construct.
The concept is theoretically and practically impossible.
It is not easy to change the temperature according to the pwn requirements
Adding heat and depleting the heat is not an easy job
It doesn't deal with the other types of equipment
Heat loss can occur in the engine
It works exactly the opposite way which is used to denote the working
Conclusion
In the end, we can only say that the Carnot engine is called the second law of thermodynamics. The efficiency of a Carnot engine depends only on the temperature that needs to be taken into consideration (both the sink and the source). The efficiency of an irreversible heat engine is always less compared with reversible heat engines. Who aims to operate between the same two reservoirs.
A very good advantage of the Carnot engine is that the Carnot cycle always wants to achieve the highest efficiency. It is a process of doing the work with efficiency and independently while at the same time focusing on working fluids.