what exactly is phaze change?

[foges]

Im quite new to phaze change and other subzero cooling, I have read a few of the guides here on this forum, but i was wondering what phaze change really is? what happenes in the process? do you put some gas into the tubes and then get them out again and cool them down? please explain

[the_new_guy]

hi,

well basical phase change works on the principal of gas law ie
PV=nRT
p-pressure
v-volume
n-number of moles
R- gas constt.
T-temp

if we increase the pressure on the gas its temp goes up, then when we cool it in the condenser the hot pressurisred vapours turn into liquide, in the evap we let the now room temp liq expand thus the temp falls.


that is phase change.


the_new_guy

[Malachia]

phase change is the change of the fysical state of an element, for example if you turn ice in water this is a phase change.
we use this fysical property to cool our processors, we put in systems gas (freon) and we make it liquid, then we turn it back to vapor state, while it turn to vapor(is called expansion) the gas absorb energy, and as you certanly know heat is a kind of energy...then if the gas absorb energy everithing around it gets cool...
to see how the system is made "for real" search in the sticked guides...

sorry for the orrible english, i hope it is comprensible :(

[<Wouter>]

gas>>>compressor>>>gas is put under pressure>>>condensor>>>gas changes to liquid because it is cooled down and put under pressure>>>evaporator (block)>>>liquid evaporates and gives of it's cold to the block>>>block freezes>>>gas>>>>back to compressor.

BTW: where goes the cap tube and the dryer in the loop?

[gclg2000]

http://www.xtremesystems.org/forums/showthread.php?t=54659

[Comp-Freak]

gas>>>compressor>>>gas is put under pressure>>>condensor>>>gas changes to liquid because it is cooled down and put under pressure>>>evaporator (block)>>>liquid evaporates and gives of it's cold to the block>>>block freezes>>>gas>>>>back to compressor.

BTW: where goes the cap tube and the dryer in the loop?Almost right ;) The liquid gass evaporates and absorbs the heat of the processor instead of "giveing cold" ;)

[foges]

ok, thanx guys. Just to recap to make sure i got it. Basically the gas is compressed in the compressor for a more effective cooling, the gas is then cooled down and logically it turnes into liquid because it goes below its boiling point, it is then fed to the processor at the processor because of the immence heat it is turned into gas again (over its boiling point) and it is fed back into the compressor. And instead of using a pump the setup uses a compressor.

Please do correct me

How much noise does a setup like this usually make? how much does it generaly cost? how does the condensor create such low temperatures?

Thanx:D:D

[MutantToad]

Not exactly. The compressor raises the boiling point of the gas via compression.
Ex: Propane (R290) boils at -40ish degrees C. You cannot reach that temperature with a mere fan and condenser under 1 atm. However, once it gets compressed, the boiling point raises, so you can condense it. Then it goes to the evap and evaporates (duh) and goes back to the compressor.

[texuspete00]

It's just a refridgerator man. That's all. Where the evaporator(where the evaporation and hence heat transfer aka cooling take place) is a copper block and not a finned type setup to have cold air blown off of it. That's all. Hell I'm not into this that much but I don't know how many pro's would be talking about this stuff as "vapor phase change" if it was your freezer. Just seems like buzz words that came out of it being for computers. It's a refridgerator my friend. You can loook up how they work anywhere. The big diff is only the evaporator, what it's designed to cool. Just imagine a block assembly instead for this to happen in and you are set.

[wdrzal]

It's just a refridgerator man. That's all. Where the evaporator(where the evaporation and hence heat transfer aka cooling take place) is a copper block and not a finned type setup to have cold air blown off of it.. That's all. Hell I'm not into this that much but I don't know how many pro's would be talking about this stuff as "vapor phase change." Just seems like buzz words that came out of it being for computers. It's a refridgerator my friend. You can loook up how they work anywhere. The big diff is only the evaporator, what it's designed to do and cool. Just imagine a block assembly instead for this to happen in and you are set.


he's correct ,if you want to learn how it works search "Basic refrigeration loop" ...... "Phase change" is the process the refrigerant goes thru inside the loop, but learning the simple loop will further your understanding.

[foges]

ok, thanx guys its much clearer now. i read a few articles on how freezers work. Some basic things that i didnt understand before:
A condensor is just a radiator with a fan and not some machine.
When a gas turnes from liquid to gas it absorbes heat creating a cooling effect, but when the gas turnes from gas to liquid it becomes warm
The compressor increases the pressure of the gas and the condensor then because of the high boiling point turnes the gas into a liquid. state by removing some of the heat of the liquid gas. The liquid turnes into a gas at the cpu (evaporator) because of the heat going over the boiling point of the gas.

Some of that is probably wrong though, so please correct me (again)

[Comp-Freak]

The liquid turnes into a gas at the cpu (evaporator) because of the heat going over the boiling point of the gas.Almost right. The pressure in the evap is a lot lower, beacause it's after the cap. tube, the liquid gets room. Because the lower pressure, boilingpoint decreases and liquid gass turns into gass, absorbing heat from the compressor.

[foges]

aha, that makes it much clearer. Just one more question, on one website i read that " If the temperature outside the fridge/freezer, is too low, the freezer won't get very cold. The fridge relies on there being warmer temperatures outside the appliance for the process to work" and was just wondering why it happenes like that?