Subzero Air temps via phase change...

[eXtenz]

I am currently wanting to make something easy for benching multiple peices of equipment, and overclocking, yes i realise that ultra low temps would be better but, would rather just use the air route...heres what i need..

air temps of perhaps -25 to -45c with lets say, 800w of heat in a closed chamber..... condensation not a problem

how low do you think a 6-8000 btu window unit could get the air without thermostat?

any input would be welcome...

[wdrzal]

1c or 33F without a defrost cycle the coil will freeze solid and the air will not flow thru the fins of the evaporator.

[eXtenz]

so what needs to be done to reach my goal? =p

[wdrzal]

so what needs to be done to reach my goal? =p

Get a good book on refrigeration and freezers either buy or from public library, learn basics,creep before your crawl. standing & walking and comes years latter. Jogging and running is about 5 to 8 years away depending on current knowledge and mechanical skill,electrical skill, proprietary refrigeration skill & thermodynamic knowledge and the most important is personal safety skills so you live to the graduation day.:yepp: :yepp: :yepp: :)

[Starkiller42]

Also, take a look at the chillboxes on EOCF. Here is a combo chiller/chillbox that Drewmeister is currently building:

http://forums.extremeoverclocking.com/showthread.php?t=258500

Walt, in my personal reading experience, in a sealed case condensation is often not a major issue. A small amount of silica is usually able to take care of any residual moisture, and there is usually not enough humidity for serious frost to form on the evap. If the case was unsealed, sure it would be a problem, but if 99.99% airtight he won't need to worry much.

Also, I would personally rate a chillbox under the "crawl" section of the phase learning curve. Little to no phase knowledge is needed for the project, no hacking apart the innards of an AC or brazing. The only real challenge comes from a creating an airtight case that will pass wires and a few copper tubes, but for anyone with a little ingenuity that shouldn't be too much of an issue.

[berkut]

Hi there

Latelly we had a technological picnic over here in warsaw and i was invited to do some benching for the public. The day was really humid and HOT, smth like 35C in the shadow (we were in a tent where there was probably even more), there were some trees to cover us, still it was damn hot... If we were to push a nice score i had to do smth:

http://i129.photobucket.com/albums/p201/berkutelbrus/PIKNIK/DSC01979s.jpg

http://i129.photobucket.com/albums/p201/berkutelbrus/PIKNIK/DSC01985s.jpg

http://i129.photobucket.com/albums/p201/berkutelbrus/PIKNIK/DSC01983s.jpg

http://i129.photobucket.com/albums/p201/berkutelbrus/PIKNIK/DSC01984S.jpg

Those are two 10 kg chunks of dry ice sitting in the box with the computer, my old thrusty cascade filled with R22/R290/R507 on the first stage and R22/R1150 on the second pushing -80C @ 4ghz 1.55V 6700 QC...

The temps inside the box were about 0C and lower, a single 120mm fan was blowing on the dry ice blocks wich i found to be enough for our needs. The motherboeard temp sensors reported the board to be 6C .

If the dry ice blocks were to be crusched to smaller bits (more surface area), with better air circulation and thicker insulation (i used whatever was availeble) i think going to -50C IS possible.

Beacause the dry ice is evaporating it rejects humidity out of the closed space, still we had some problems with ice forming on the blades of the fans.

This is a really inexpensive technique, probably about 10$ per bench... and really clean too.

[dinos22]

good thinking berkut

very nice :clap:

[berkut]

I forgot to say those 2 blocks would be good for a entire day of benching.

[dinos22]

I forgot to say those 2 blocks would be good for a entire day of benching.

yeah DICE blocks that size don't evaporate that easy :D

[n00b 0f l337]

Looks very good berkut, a good way to do it. As for the coil icing up, yes it will unless you have dehumidifier the box to begin with.