Heat Engines

What they are, and how they work. These are anything that uses “heat” to create mechanical motion. Deriving Carnot efficiency from basic principles. What is efficiency and how efficient certain engines are, such as a car engine.

[theotherguy]

Does the human body count as a heat engine? It is largely warm and it does produce mechanical work.

[bilsid]

if T hot goes to infinity, we can get 100% efficiency

[giorgiocanal]

Wrong again. The efficiency of a piston heat engine is not the ratio between the surface of the piston exposed to the fluid and the total internal surface of the machine.

[МихайлоСєльський]

1. This idea of "only one of six sides of the box moves, .. and the efficiency (therefore) is close to 1/6th" is such a facepalm... I've almost lost my breath. It's like telling smthn like "cumulative ammunition is 6 time less powerfull because explosion goes only one way, instead of going in every direction".

2. T(hot) is not a temp of ignition, it's max temp in cycle. In ICE's it can reach up to almost 3000K. That calculation is completely wrong.

3. "20...25% efficiency at best" - wrong again. At best (for optimal load and speed conditions) it can reach up to 35%...45% for petroleum and up to 40%...50% for diesel piston engines.

I appreciate your videos, but this one is terribly misinformative.