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.

Is it possible to save the rejected heat Qout in a power cycle? The answer is NO, because without the cooling in condenser the cycle cannot be completed. Every heat engine must waste some energy by transferring it to a low-temperature reservoir in order to complete the cycle, even in idealized cycle.

Explain. It is not possible for a engine to operate without rejecting any waste heat to a low temperature reservior. In a heat engine, heat is transferred from a higher temperature level called source to a lower temperature level called sink. Work is obtained during this process.

Because the hot reservoir is heated externally, which is energy intensive, it is important that the work is done as efficiently as possible. In fact, we would like W to equal Qh, and for there to be no heat transfer to the environment (Qc=0). Unfortunately, this is impossible.

The Kelvin-Planck statement is: “it is impossible for any device that operates in a cycle to receive heat from a single reservoir and produce a net amount of work.” Another common statement is the Clausius statement: “It is impossible to construct a device that operates in a cycle and produces no effect other than the …

If this process is reversed, the reversed heat engine takes heat from low temperature reservoir and rejects heat to a high temperature reservoir with external work is done on the system. This is the called as a heat pump or a refrigerator.

BTU

An important and useful corollary of the second law of thermodynamics, known as the inequality of Clausius, states that, for a system passing through a cycle involving heat exchanges, (1.22a) ​ where dQ is an element of heat transferred to the system at an absolute temperature T.

This is unfortunate, since a very simple calculation shows that it is physically impossible for evolution to violate the second law of thermodynamics. It is important to note that the earth is not an isolated system: it receives energy from the sun, and radiates energy back into space.

The second law of thermodynamics means hot things always cool unless you do something to stop them. It expresses a fundamental and simple truth about the universe: that disorder, characterised as a quantity known as entropy, always increases.

3 Answers. Do black holes violate the first law of thermodynamics? No. See Wikipedia re the first law of thermodynamics: “The first law of thermodynamics is a version of the law of conservation of energy, adapted for thermodynamic systems.