Carnot Cycle: Understanding Why Real Engines Fall Short

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Discussion Overview

The discussion centers on the reasons why real engines do not achieve the efficiency predicted by the Carnot cycle, exploring the differences between idealized reversible processes and the irreversible processes of actual engines.

Discussion Character

  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant suggests that real engines do not attain Carnot efficiency because they do not operate on the Carnot cycle, which is characterized by slow processes.
  • Another participant notes that real engines experience friction and other losses that contribute to lower efficiency.
  • A participant explains that the Carnot cycle involves reversible processes that require infinite time to complete, while real engines operate in finite time, leading to irreversible processes and increased entropy.

Areas of Agreement / Disagreement

Participants express differing views on the types of processes involved in real engines versus the Carnot cycle, indicating that the discussion remains unresolved with multiple competing perspectives.

Contextual Notes

There are limitations regarding the assumptions about the nature of processes in real engines and the definitions of efficiency being used, which remain unresolved.

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Why do real engines never attain the efficiency of the Carnot cycle?
 
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Two reasons:
-First, they don't use the carnot cycle because its acts slowly.
-Second, all real engines produce friction and other losses.
 
So what type are processes are we talking about?
 
Carnot cycle: reversible processes require infinite time to complete.

"Real engine:" processes are completed in finite time, and are, therefore, irreversible, meaning more heat is lost in increasing the entropy of the universe.
 

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