What Is a Carnot Engine and Why Is It Important in Thermodynamics?

[Maxwell]

Hey everyone,

I was sick when we started this unit. I've been trying to catch up, and need to ask a couple of broad questions.

1) What is a Carnot engine? Or the Carnot cycle? What is it used for ? Why do we can about perfect conditions??

2) When people keep mentioning "reservoirs", in problems, what do they mean?

3) What is a temperature gradient?

4) What is a refrigerator? (If it is different than the everyday appliance). And how do we describe/use it?

5) What are the first two laws? And how are they applied?

And any other important facts about Thermodynamics!

Thank you very much.

(PS - I'm going to read my book as well, as I have not gotten to most of these things in the chapters. But from my experience you guys explain things better than the book so I asked them here!)

 

[Chi Meson]

A "Carnot engine" is a theoretically perfect heat engine where the maximum possible efficiency is achieved. None actually exist.

A heat engine is capable of making two different bodies at different temperatures do useful work merely by allowing heat to flow from hot to cold. THe two bodies are known as "resevoirs."

For a "hot resevoir" think of a large, large tub of hot water (So large that the temperature does not change significantly as a little bit of heat leaves it).

For the "cold resevoir" think of the atmosphere outside; it's something that the heat can flow into.

The carnot cycle is four actions of the piston: isothermal expansion, adiabatic expansion, isothermal compression, adiabatic compression. After one cycle the gas is back to its starting position on the PV graph.

Oops, got to go...