- #1
vmars316
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Hello & Thanks,
Is it possible to use only a powerful fan
without a compressor to make very cold air ?
Thanks
Is it possible to use only a powerful fan
without a compressor to make very cold air ?
Thanks
What do you think? Why would the air coming out of the fan be colder than the air going into the fan?Hello & Thanks,
Is it possible to use only a powerful fan
without a compressor to make very cold air ?
Thanks
Yes, obviously,What do you think? Why would the air coming out of the fan be colder than the air going into the fan?
Obviously WHAT?Yes, obviously,
why would any point be colder than any other point?But I am thinking of a fan blowing into a funnel shaped thing
where the speed of the air increases as it goes thru
the very narrowest end of funnel shaped thing .
And if the funnel was made of iron
I am wondering where on that funnel would be the coldest point ?
But I am thinking of a fan blowing into a funnel shaped thing
where the speed of the air increases as it goes thru
the very narrowest end of funnel shaped thing .
And if the funnel was made of iron
I am wondering where on that funnel would be the coldest point ?
Where would the coldest point begin (before it spread) ?
If air inside vacuum cleaner's hose has mass 0.01 kg and its speed is 10 m/s, then
the air has kinetic energy 0.5 J.
That air's thermal energy is reduced by the amount of its kinetic energy, 0.5 J. That means that the air in the hose is just a little bit cooler than the air in the room where the vacuum cleaner is.
Because the cold has a starting point .Obviously WHAT?
why would any point be colder than any other point?
This is just wrong. Center of mass energy is independent of thermal energy. Do you think astronauts get colder and colder as they accelerate into space?
This sort of question has come up before. First, a "fan" and a "compressor" are similar devices physically, having the same basic purpose and in many cases operating principle; to move air by increasing its pressure. The terminology difference is typically just based on how much pressure they can provide.Hello & Thanks,
Is it possible to use only a powerful fan
without a compressor to make very cold air ?
Thanks
I really don't have any idea what you mean by this. What does it mean for the cold to "begin"? Some effect has to make the air colder - what effect do you think that is?But I am thinking of a fan blowing into a funnel shaped thing
where the speed of the air increases as it goes thru
the very narrowest end of funnel shaped thing .
And if the funnel was made of iron
I am wondering where on that funnel would be the coldest point ?
Where would the coldest point begin (before it spread) ?
[separate post]
Because the cold has a starting point .
Think about it :
Suppose the funnel is made of a stack of iron rings .
Each ring having a smaller diameter than the ring above it .
And in between each ring is a ring of an insulating material
keeping the cold from spreading .
Again , where does the cold begin ?
This sounds rightWe just need to create a place we the compressed air can expand into. Then the compressed air does work and cools.
The can gets cold because it contains a chemical liquid that boils at below room temperature and a certain pressure. So when you spray it, the chemical boils and that absorbs heat, making the can cold.This sounds right
But :
When I use a can of bug spray ,
the can in my hand gets cold .
I don't know if the spay is cold or not (too toxic to check it out) .
But the hole in the nozzle is much smaller that the tube leading to it .
So there is work being done there also as air is released into the atmosphere...
What's going on there exactly ?
This sounds right
But :
When I use a can of bug spray ,
the can in my hand gets cold .
I don't know if the spay is cold or not (too toxic to check it out) .
But the hole in the nozzle is much smaller that the tube leading to it .
So there is work being done there also as air is released into the atmosphere .
What do you mean by "compressed air can"? Do you mean the small cans that you use to blow dust off computer keyboards and other electronics? Those use a liquid hydrocarbon too...As mentioned by @russ_watters , the can contains some liquid that becomes gas.
But what if we let out half of the contents of a compressed air can? The can gets cool, right?
So it must be so that the gas in the can is doing work as it is expanding. Only work there is to do is to push the gas that is going out, push it from the back, so to speak.
What do you mean by "compressed air can"? Do you mean the small cans that you use to blow dust off computer keyboards and other electronics? Those use a liquid hydrocarbon too...
So you are saying that the insect spray contains freon ?The can gets cold because it contains a chemical liquid that boils at below room temperature and a certain pressure. So when you spray it, the chemical boils and that absorbs heat, making the can cold.
Not freon. The MSDS for Raid, for example, says it contains 10-30% isobutane, some propane and a couple of other hydrocarbons.So you are saying that the insect spray contains freon ?
Why would it contain freon...
Because liquids are denser than gases so you can fit more in the can..instead of just compressed air ?
And what is the name of the law that says
When compressed air does work it cools ?