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“A device which works on a cycle and creates no other impact than the generation of work and the transmission of heat from a single body is impossible to build.”
The terms “thermal reservoir” and “single reservoir” are used in this assertion. A reservoir is a huge item that maintains a steady temperature whereas energy is extracted. The earth’s atmosphere, enormous bodies of water like lakes and oceans, and so on can all be used to mimic such a system.
The presence of a system which develops a net quantity of work from a heat transfer derived from a thermal reservoir is not ruled out by the Kelvin–Planck assertion. A system conducting a cycle, according to this assertion, cannot generate a positive net quantity of work from a heat transfer derived from a thermal reservoir.
second law of thermodynamics
The entropy of an isolated system never decreases with time, according to the second law of thermodynamics. The unpredictability of the universe is referred to as entropy. As a result, any spontaneous process increases the entropy of the universe (S).
Heat moves from a heated body to a cool one on its own.
It is impossible to translate all of what one hears into effective labour.
Every solitary system eventually gets unstable.
Kelvin Planck Statement
As per the Kelvin Planck Statement, it is impossible to develop an engine whose sole aim is to ease the conversion of heat from a high-temperature source/reservoir into an equal quantity of work. Furthermore, this is a specific instance in terms of the second law of thermodynamics.
The Heat Engine Hypothesis is another name for the Kelvin–Planck statement. This statement, which is part of the second rule of thermodynamics, means that it is necessary to design a heat engine which can consume energy in the form of heat while also producing work of equal magnitude. Energy is derived from a single thermal reservoir and is in the form of heat in this idea.
The Kelvin-Planck statement is formed by combining two separate assertions. Furthermore, these assertions are known as the Kelvin and Planck statements since they were stated by Lord Kelvin and Planck.
Understanding Kelvin Planck Statement
As per Kelvin’s assertion, any matter cannot be mechanically affected by cooling below the greatest cooling temperature of the surrounding objects. According to Planck’s statement, the entire sum of entropies in a reversible system will remain constant. Most notably, the Kelvin-Planck Statement was created by combining both of these assertions.
One thing to keep in mind is that heat (Q) and work (W) are the two types of energy. Moreover, both of these variants are interchangeable and use the same SI unit of Joules. This means because effort can be converted into heat and vice versa.
The whole conversion of the effort into heat can take place here. Heat, on the other hand, cannot be converted completely into effort. As a result, experts refer to work as high-grade energy whereas heat is referred to as low-grade energy.
Imagine the Perpetual Motion Machine of the Second Kind, a hypothetical contraption (PMMSK). Moreover, Wilhelm Ostwald presented this system, which would work by taking energy from a body in the form of heat. Wilhelm Ostwald explains the Kelvin-Planck Statement in this way.
kelvin planck statement diagram
The diagram of kelvin planck statement is given as:
Working of Heat Engine:
A continual exchange of heat is required for the heat engine to perform. Moreover, the working fluid must transport heat between the low-temperature QL heat sink/reservoir and the high-temperature QH heat source/reservoir. Furthermore, efficiency is the most important factor here.
The amount of productive work that can be done with a given amount of input is the efficiency of a heat engine.
Application of Kelvin Planck Statement
Thermodynamics has a wide range of applications in the actual world. Heat energy is converted into effort energy in order to move the boat. In addition, the water body contains a significant amount of heat.
As a result, the extraction of heat from the body is appropriate. After that, it can be totally converted into power in order to work. Consequently, in a real-life situation, it does not operate.
It is necessary to have a well-equipped engine with fuel in order for the boat to move forward. Furthermore, this would act as an external heat source for propulsion.
As a consequence, we realise that constructing an engine which can assist the total conversion of heat from one reservoir to work is difficult. This, above all, assists the Kelvin Planck assertion.
Example of Kelvin Planck statement
Wilhelm Ostwald invented the perpetual motion machine of the second kind (PMMSK), which was a theoretical machine designed just to convert heat into work without creating any other effects.
Conclusion
According to the Kelvin Planck Statement, developing an engine whose primary purpose is to facilitate the conversion of heat from a high-temperature source/reservoir into an equal amount of work is impossible. Additionally, in terms of the second rule of thermodynamics, it is a unique situation.
The Kelvin–Planck assertion is also known as the Heat Engine Hypothesis. This remark, which is part of thermodynamics’ second law, implies that a heat engine must be designed that can consume energy in the form of heat while also creating work of equal magnitude. In this concept, energy is derived from a single thermal reservoir and is in the form of heat.
