So I’m kinda rusty on heat engines, but from what I can remember, heat is used to increase the pressure of the gas, moving a piston that then increases the gas pressure in another piston, and so on. Is it possible to use a gas that would expand and move a piston when brought to room temperature, and then contract and go back below room temp. To me it just seems like you’d need a gas that has these properties at room temp. Only problem is that conservation of energy would probably require that the energy put in to keep the engine cold would be greater than the energy output.
So here’s my idea. In order to keep the engine cold, you’d need something else to be hot. The energy to do all of this is supplied by the cold engine. Instead of wasting that excess heat that we need to keep the engine cold, instead use it as the heat input for another heat engine.
To recap, you have an engine that is kept at a cold temp, and a gas that will work the heat engine at room temp. The energy from this cold heat engine will be put into extracting heat from the engine and passing it to a heat dump. Then, this heat is used on a regular heat engine to get a positive energy output. Since the energy output of the cold engine is < the needed energy input, some of this energy would be needed to go back to keep the cold engine cold. It should still have a positive energy output after this though, because energy is conserved - ‘free’ energy came from the environment
Edit: assuming that it is possible to have a room temp heat engine, the only potential problem I see is that it may be impossible to get the efficiency high enough to the point where I have excess energy after taking energy from the hot engine for the refrigerator.
Submitted January 30, 2018 at 12:06PM by PackaBowllio28 http://ift.tt/2DMxoqO AskPhysics
