Why is a Carnot engine Impossible?

What are the limitations of Carnot engine?

Carnot vapour power cycle is an ideal cycle, efficiency of which is independent of the working substance . But it is extremely difficult to operate in practice because of the following reasons : (a) It is difficult to compress a wet vapour isentroprically to the saturated state as required by the process (4-1).

Why can Carnot engine Cannot be 100 efficient?

In order to achieve 100% efficiency (η=1), Q2 must be equal to 0 which means that all the heat form the source is converted to work. Hence negative temperature of absolute scale is impossible and we cannot reach absolute 0 temperature. …

Why is it impossible for a heat engine to be completely efficient?

It is impossible for heat engines to achieve 100% thermal efficiency () according to the Second law of thermodynamics. This is impossible because some waste heat is always produced produced in a heat engine, shown in Figure 1 by the term.

What is Lord Kelvin statement?

The Kelvin–Planck statement (or the Heat Engine Statement) of the second law of thermodynamics states that it is impossible to devise a cyclically operating heat engine, the effect of which is to absorb energy in the form of heat from a single thermal reservoir and to deliver an equivalent amount of work.

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What are the limitations of a Carnot cycle for refrigeration?

Limitations of Carnot cycle:

This is difficult to achieve in practice. In addition, the volumetric refrigeration capacity of the Carnot system is very small leading to large compressor displacement, which gives rise to large frictional effects.

What are the challenges for Carnot refrigeration cycle?

Practical difficulties with Carnot refrigeration system:

Such variation of speed in a stroke is not possible and makes it impracticable. With finite specific heats of a medium, it is not possible to carry out isothermal heat transfer process in practice.

What are the limitations of reversed Carnot refrigeration cycle?

Reversed Carnot refrigeration cycle with liquefaction and vaporization of the refrigerant. There are two major drawbacks to the reversed Carnot cycle with phase-change refrigerant: 1. The adiabatic compression between Tlow and Thigh occurs in the liquid–vapor region, which is why it is called wet compression.

What is the efficiency of Carnot engine?

The efficiency of carnot’s engine is 50%.