# Questions tagged [carnot-cycle]

A theoretical ideal thermodynamic cycle which provides an upper limit on the efficiency that any classical thermodynamic engine can achieve during the conversion of heat into work, or conversely, the efficiency of a refrigeration system in creating a temperature difference by the application of work to the system.

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### Efficiency of thermal (rankine) power plants based on ambient temperature?

so I'm preparing for an interview and this is a common question that they always ask, Say there are two power plants working on ideal rankine cycle One in Alaska (low ambient temperature) and one in ...
1 vote
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### Isothermal irreversible expansion of ideal gas

I am studying Thermodynamics in my first year and I don't quite understand the process of isothermal reversible/irreversible expansion. Below is a P-V graph I found on Google, just to help me ...
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### Confusion about forces in the work done on the piston by the gas in Carnot cycle

I was drawing a free body diagram of the 3rd step of the Carnot cycle as shown below. The forces with - sign are reaction forces to the forces without the sign, according to Newton's 3rd law of ...
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### Why don't we really consider the TOTAL (SYSTEM +SURROUNDINGS) entropy change in Carnot cycle?

During a Carnot cycle, why don't we consider the increase in entropy of surrounding by the energy given to surrounding via work done by gas piston? I mean we want to find the total entropy change then ...
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### Relation between heat quotient and temperature quotient

Is $$\frac{Q_c}{Q_h} = \frac{T_c}{T_h}$$ valid for any reversible ideal cycle Or just for the Carnot cycle?
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### Carnot cycle with varying reservoirs

I was thinking what will happen to the standard Carnot cycle, if instead of - say - the usual cold reservoir, we adopt a smaller refrigerator, whose temperature in fact changes after the heat release ...
1 vote
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### Why adiabatic expansion happens in Carnot cycle?

$A \rightarrow B$: Isothermal expansion happens. Since the internal energy purely depends on the temperature ($E_{int} = knRT$, $k = \frac{3}{2},\frac{5}{2},3$), then $\Delta E_{int}=0$ in an ...
539 views

### How can we say that work done by carnot engine in a cycle equals net heat released into it even when it is operated b/w 2 bodies and not 2 reservoir?

When a carnot engine is operated between 2 reservoir then after each cycle it return to its initial state so change in internal energy is zero and so work done by it equals net heat released into it. ...
108 views

### How does a reversible Carnot cycle transform heat to work?

To make clearer what I am asking let me introduce a new terminology to avoid any misunderstandings. Let the heat flow, which is rate, between a reservoir and an engine be denoted by $\mathfrak J$ and ...
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### Change in entropy of engine and the hot bath in a cycle

I want to clarify that this question is not a homework-type question. I have provided its solution and the apparent discrepancy. This is a question from a national competitive exam I gave. I am very ...
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### Carnot Cycle Question

I have two questions surrounding the Carnot cycle. The typical diagram for a Carnot cycle is shown here: I have several textbooks that discuss this cycle, but what none of them do is explain how ...
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### Optimality of the Carnot cycle

It is well-known and is stated always and everywhere that the Carnot cycle is the most efficient thermodynamic cycle. Although stated as such it is rarely proven. One proof is in the article "...
1 vote
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### Carnot engine (theorem) proof

I am facing issues in the proof. Some links to the proof of carnot engine: https://en.wikipedia.org/wiki/Carnot%27s_theorem_%28thermodynamics%29 https://www.khanacademy.org/science/physics/...
1 vote
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### What is the need of adiabatic compression in Carnot cycle?

Why do we need to compress the gas adiabatically after the isothermal compression of gas? What if we just skip this step? What will be the consequences? By "skipping this step", I mean, ...
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### Is Carnot cycle the only "most efficient" cycle? [duplicate]

In all the books, that I have studied so far, they say that Carnot cycle is the most efficient cycle. But why isn't any other reversible process as efficient as Carnot cycle? Can somebody please ...