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chilly1, How thickness the neoprene is ?Quote:
Originally posted by chilly1
Closed sell neoprene foam. Assembled with solvent/glue. 3m 2229 mastic tape for seal. Nylon mounting hardware..
Should this type of insulation (solvent/glue) be efective ?
sorry all questions..:)
1/2 inch to 3/4 inch plus a layer or two of 0.125 foam tape...
chilly1, what's up with your Supercascades ? :D ;)
LOl you guys were talking about the THG P4 overclock...they claim that they use a vapochill for the northbridge....hmmm not in this pic :P
Lol. My motto, never trust THG!
So true!!Quote:
Lol. My motto, never trust THG!
Brainfreeze that is REALLY well spotted.
Thank you :)Quote:
Originally posted by LoudHoward
Brainfreeze that is REALLY well spotted.
But its really lousy of THG ! they havent event noticed themselves! stupid stupid THG. they completely butt :smileysex themselves :P
lol the wire even goes right across the picture :P
OMG!:eek:
you guys are going to think i'm stupid but...
You can use aluminum for your evaporator blocks? This is such good news for me! i just figured you could only use copper becuase it was a stronger material and would hold better at a higher pressure i guess i was wrong...
We have a Welding/CNC shop and all the aluminum i could ever want in stock. I've leaned away from building my own Phase change system becuase frankly, machining the copper looked like more trouble that it was worth plus it doesn't machine very well in my expierence. We have Aluminum welders and tons of aluminum, maybe i'll autocad up a few designs and rather than brazeing (which i SUCK at) i'll just weld the blocks up!
DGeNeRaT3
If i'm succsessfull and you guys like them, i'll run some off for people who ask. :D
I would hold off til testing is done the first aluminum block looked like a coke can (not enough internal bracing and the bottom was .0825 inches thick,,, On hold til I finish a few other things...
Quote:
Originally posted by DGeNeRaT3
OMG!:eek:
you guys are going to think i'm stupid but...
You can use aluminum for your evaporator blocks? This is such good news for me! i just figured you could only use copper becuase it was a stronger material and would hold better at a higher pressure i guess i was wrong...
We have a Welding/CNC shop and all the aluminum i could ever want in stock. I've leaned away from building my own Phase change system becuase frankly, machining the copper looked like more trouble that it was worth plus it doesn't machine very well in my expierence. We have Aluminum welders and tons of aluminum, maybe i'll autocad up a few designs and rather than brazeing (which i SUCK at) i'll just weld the blocks up!
DGeNeRaT3
If i'm succsessfull and you guys like them, i'll run some off for people who ask. :D
Well ... that makes me very happy to hear ... I am shooting for the magical -100°C to chill a liquid.Quote:
anything colder than -120c is really a pain in the as, though im sure you will all want to learn that the hard way. Personaly i dont think its really worth the effort. i have gotten to -152c though it wasnt very stable. as you know, one of the reasons we use refrigeration systems as aposed to ln2, is the stability. i have down sized my operations. in an effort to build a stable, happy, and healthy -100to-115c system for our purposes. no more chasing rainbows. if its not stable, its almost not worth mentioning. though some may beg to differ.
Currently working on the traditional cascade which I am building to gather experince at low temperatures. After that I will try for an autocascade.
Good Luck to everyone ... :D
Quote:
Originally posted by chilly1
I would hold off til testing is done the first aluminum block looked like a coke can (not enough internal bracing and the bottom was .0825 inches thick,,, On hold til I finish a few other things...
Forgot to mention aluminum will become stronger the colder it gets... It doesn't reach the glass stage til a lot closer to absolute zero.. And another supposition is that the thermal conductivity in a metal will radically change as temperature drops, due to the valence electrons dropping to a lower orbit. Where this happens I don't know but I intend to find out...
I have always felt that the only stupid question is a question you dont ask. Since i am asking this question it isnt stupid ;)
Electrolysis.
I know that it happens when water is used to cool a system, esp if you are using aluminum and another metal somewhere in the system. I know that water plays a big part in electrolysis too, but is it possible that elecrolysis may occur with refrigerant in place of water?
Not in metals, valence electrons ARE the lowest orbitals. For a metallic conductor conduction happens in the conduction band. There is no valanence coduction because electrons are held tightly into localized orbitals. So for conduction to occur an electron must escape into the conduction band (which is delocalized across the entire conductor and thus allows energy to travel at extremely high speed across macroscopic distances).Quote:
Originally posted by chilly1
Forgot to mention aluminum will become stronger the colder it gets... It doesn't reach the glass stage til a lot closer to absolute zero.. And another supposition is that the thermal conductivity in a metal will radically change as temperature drops, due to the valence electrons dropping to a lower orbit. Where this happens I don't know but I intend to find out...
An electron is promoted to the conduction band by absorbing enough thermal energy to overcome the energy binding it into the valence band. This is why materials like LEDs that use semicoductor elements to create light vary the color of light produced with temperature. At low temperature very little energy is available so the smallest allowed jumps happened and you get lower frequency (low energy) light. At higher temps higher energy jumps are permitted and you can get higher freqency light. If you're ever bored dip a green LED into liquid nitrogen. It'll shift towards red. Get it cold enough and no electrons escape the valence band and it becomes a nonconductor.
Anyway this means that the coduction band is most effective at high temperatures . . . to a point. Thermal energy messes up the neat FCC stucture of most good conductors. As the structure is disturbed the conduction band is also distrubed which slows the flow of electrons (and thus heat riding on the electrons). Theres actually some ideal temperature for conduction that balances out these two effects in metals.
Note that i did not mention superconduction because Al and Cu have no super conductive properties at any temperature.
This is a very good question. Electrolysis itself cannot happen because that is dependant on water decomposing to form oxygen, however galvanic corrosion between copper and aluminum isn't dependant on electrolysis exactly.Quote:
Originally posted by someone
I have always felt that the only stupid question is a question you dont ask. Since i am asking this question it isnt stupid ;)
Electrolysis.
I know that it happens when water is used to cool a system, esp if you are using aluminum and another metal somewhere in the system. I know that water plays a big part in electrolysis too, but is it possible that elecrolysis may occur with refrigerant in place of water?
In theory it can happen anytime the two metals are in direct contact. However realisitcally the effect would probably be very very slow since the refrigerant would not be dissolving the two metals and thus giving them an easy way to react. I think it should be ok, but its been a long time since i took thermo chem class so I can't really remember the exact reactions.
No...Quote:
Originally posted by saratoga
Not in metals, valence electrons ARE the lowest orbitals. For a metallic conductor conduction happens in the conduction band. There is no valanence coduction because electrons are held tightly into localized orbitals. So for conduction to occur an electron must escape into the conduction band (which is delocalized across the entire conductor and thus allows energy to travel at extremely high speed across macroscopic distances).
An electron is promoted to the conduction band by absorbing enough thermal energy to overcome the energy binding it into the valence band. This is why materials like LEDs that use semicoductor elements to create light vary the color of light produced with temperature. At low temperature very little energy is available so the smallest allowed jumps happened and you get lower frequency (low energy) light. At higher temps higher energy jumps are permitted and you can get higher freqency light. If you're ever bored dip a green LED into liquid nitrogen. It'll shift towards red. Get it cold enough and no electrons escape the valence band and it becomes a nonconductor.
Anyway this means that the coduction band is most effective at high temperatures . . . to a point. Thermal energy messes up the neat FCC stucture of most good conductors. As the structure is disturbed the conduction band is also distrubed which slows the flow of electrons (and thus heat riding on the electrons). Theres actually some ideal temperature for conduction that balances out these two effects in metals.
Note that i did not mention superconduction because Al and Cu have no super conductive properties at any temperature.
http://www.allaboutcircuits.com/vol_1/chpt_12/6.html
http://sub.allaboutcircuits.com/images/10226.png
"meaning that resistance increases with increasing temperature"Quote:
The "alpha" (á) constant is known as the temperature coefficient of resistance, and symbolizes the resistance change factor per degree of temperature change. Just as all materials have a certain specific resistance (at 20o C), they also change resistance according to temperature by certain amounts. For pure metals, this coefficient is a positive number, meaning that resistance increases with increasing temperature
most materials increase in resistance with increase in temperature. certain substances such as germanium and silicon decrease in resistance with increase in temperature.
Quote:
Originally posted by saratoga
Note that i did not mention superconduction because Al and Cu have no super conductive properties at any temperature.
please stop making up information. the critical temperature for Aluminum is 1.19K.
http://www.faqs.org/docs/electric/Ref/REF_3.html
I wasn't asking about eletrical charestics but the ability for it to conduct heat and strength of materials.
in that case the physics are not good :(Quote:
Originally posted by chilly1
I wasn't asking about eletrical charestics but the ability for it to conduct heat and strength of materials.
http://hyperphysics.phy-astr.gsu.edu...heat/hcon5.gifQuote:
At a given temperature, the thermal and electrical conductivities of metals are proportional, but raising the temperature increases the thermal conductivity while decreasing the electrical conductivity
http://hyperphysics.phy-astr.gsu.edu.../thercond.html
Good find Read down further links to thermal conductivity...
Basically the drop in temperature of 200 C will make little differance and aluminum is a little more than half what copper is Per gram per cm2 . It all has to do with free electrons.. So in theroy Aluminum should only conduct 1/2 the heat of copper but what in pratice? What about the interface between the aluminum in the block and the refrigerant? What happens here?
Gotta test it anyway. What I really wonder about is when the interface temperature reaches -200 what will happen to the conductivity Will it increase? As aluminum has less mass and the temperature gradient is dependant upon mass , does that mean that thermal conductivity increase as the temperature drops faster with a less massive material?
no offence chilly, but if you read what i posted above you would see that thermal conductivity decreases with temperature. Aluminum will only conduct heat worse the colder you get it.
I spent a little tim reading the data and the Wiedemann-Franz Law, basically it says that thermal conductivity is proportional to the free electrons since both electrical conductivity and thermal conductivity use "electron fog" or the available electrons to conduct, However as temperature increases thermal conductivity increases due the available energy level of the electrons peresent and the same applies to electrical conductivity as the free electrons need more potential to be pushed from thier orbit at higher temperatures. At lower temperatures he inverse is true. Ok I got ya I was suprised that the difference betweel 0C and -100C was so small. So the best material to build a block out of would be one that had a negitive temperature coeffecient. where it would increase in electrical conductivity as temperature unfortunatly all these materials currently availaible are also not good conductors to begin with... The formla were not explained in your post the website (when I had time to look at it) explained the usages of the formula..
Looks like the negative effect of temperature dissapear below -60 to -100 and after that thermal conductivity increases exponentially, Thx John....
From;
http://web.mit.edu/lienhard/www/downloadform1.html
looks like @ -200c copper is a better thermal conductor than silver, wow
u should use melt copper solder as TIM
I would be great if we could replace the chip with a manafactured one that had channeling for refrigerant and ports and lines to attach. So that we could cool the circuits directly no heat spreader and no conductors between the refrigerant and the silicon..