would an engine/motor/etc be more efficient in space?

[Stevil]

bored in a maths methods class i gots to thinking about engines.

and i thought that if an engine is more efficient in space/a vacuum.

 

well there is no air or anything ie. no sound. does this mean no energy is lost to sound, so more goes into the engine?

but sound will still go through the material of the machine wouldn't it? and if it did, would it be more/less/same than normal. ie sound energy that normal goes thru the air instead goes thru the machine.

 

also, if u had it in zero-g then there won't b any of those problems caused by that pesky gravity.

 

now, if sound energy did start passing thru the machine it would cause it to vibrate since sound is movement of particles through a medium etc etc. could u harness this vibration and salvage some of the energy. i doubt this, or else it could b employed here.

 

could u make really efficient engines in space thanks to the zero-g, vacuum and abundance of solar energy?

 

now another engine idea:

create like, a donut shape in space and put water in it.

set it spinning so the water inside is 'slooshing' around. and u have a hydo set up in there to get energy from the water passing thru it.

i have my doubts on this one. i can visualise the water slooshing at the same speed as the donut is spinning. so it's basically stationary. is this what will happen? if it is, could u use the basic ideas to create a space based hydro generator?

 

well, i suppose these ideas seem a bit lame to most who read it, but its just something i came up with and i'd like to know why or why not it'll work or if it'll need some changes. thanks

[blike]

I'm not sure about the first one. I would assume that the energy is still lost, its just not transmitted through space.

 

About your hydro generator...You are correct that the water would eventually be spinning at the same speed as the donut. However, the instant you try and harvest energy from a stationary outside source both the water and the donut will lose their rotational speed and energy will have to be expended to keep it rotating at a constant speed.

[alt_f13]

I agree with blike... the energy lost to sound through the air normally would just be lost through the engine and converted into thermal energy, possibly making the engine *less* efficient.

 

I have a generator idea for you, perhaps within the realms of the Dyson Sphere, a solar based space colony. A turbine that uses solar wind much like the solar sail idea for space ships. It would work like a water wheel whose sails fold up on the wind-opposing part of the rotation.