Low power butane single stage

[Coyote]

Hi guys, long time no see. Im building a new unit for my 24/7 rig, and i want to try going for really low power. Im aiming for 0c to 10c load temps, i would even settle for 20c during hot summer days. Im running a 3770K, i guess i would like to go for 4.5ghz with low vcore as possible.

Im planning on using a 90w compressor with butane, but i have no clue what size and lenght cap tube i should use, since its completely different from anything else i built. If im not mistaken, R600 should match the performance of R12, correct?

Anyone built something like this and can give me some advice? Cheers.

[Kevin Hotton]

Hi Coyote,

The standard substitute for R12 is R134a. Butane has too high a boiling point nearly 0C. Iso-Butane would be better (normal boiling point -11.7C). I can't advise on the captube without some time spend calculating. Once you settle on refrigerant load and temperature, I may be able to help.

Kevin

[Coyote]

you are right, R600 is -0.5c only ... mmm maybe i should add a bit propane into the mix to lower the boiling temp a bit.

[Sk_rmouche]

Isobutane is perfect for your range of temperature ( even R134A should do the job with tiny MBP compressor ).

With a chiller, a TXV instead of cap tube is way better to control fluctuant load, and it isn't a lot more expensive, given the price of the 30 meter cap tube coil at suppliers, unless you find someone to sell you a few meters ...

[Coyote]

i can get cap tube by the meter, yes. but a TXV would be nice, but last time i checked (and this was many years ago), there were no TXV for such low heat loads. Has that changed?

BTW, were would you usually get isobutane? i was planning on using butane from a can for camping stoves, passed through a couple filters/dryers. But i 99% sure thats regular butane and not isobutane.
As an alternative i was thinking using a mix of 80% butane and 20% propane to get the boiling point near -10c while keeping a low pressure on the discharge.

[Sk_rmouche]

No TXV for such low heat load... But we don't have any idea about YOUR load. Danfoss TE-2 TXV series is usable for loads < 1 kW, even a few hundred watts.

Search for 0X orifice. That's what I use in tiny bar freezer, about 200 W @ -10?C and it works great.

Isobutane ( R600a ) is very easy to find in little bottle, because it doesn't meet any regulations. Try eBay or specialized shop.

[Coyote]

I mentioned im using a 3770K @ 4.5ghz with low vcore, so thats what? 150-200w?

[bartx]

I'd use a water chiller with temperature controller. Much easier to tune and with 2-3l reservoir compressor will be turning on not so often.

[tiborrr]

I mentioned im using a 3770K @ 4.5ghz with low vcore, so thats what? 150-200w?
3770K @ 4.5 at low volts is maybe ~ 100-110W.

A 12V DC variable speed compressor 3-5ccm is the only quiet and low power solution (20-80W power draw) and you can probably achieve around -10?C on R-134A at such load with very healthy discharge.

[Coyote]

I'd use a water chiller with temperature controller. Much easier to tune and with 2-3l reservoir compressor will be turning on not so often.

A waterchiller is a very voluptous unit, that requires lots of insulation. and the efficiency of cooling a liquid, then using that liquid to cool the heat source, is lower than a direct phase change unit. a -10c phase change unit, needs a very light insulation, and the insulated area is quite small (suction line and evap basically).


3770K @ 4.5 at low volts is maybe ~ 100-110W.

A 12V DC variable speed compressor 3-5ccm is the only quiet and low power solution (20-80W power draw) and you can probably achieve around -10?C on R-134A at such load with very healthy discharge.

if thats the heat load, thats even better than i thought. thx.

i already got a compressor, its a Huayi AES35D. Thats a 3.5cc 90w compressor.
http://img826.imageshack.us/img826/8319/iw5f.th.jpg (http://img826.imageshack.us/i/iw5f.jpg/)http://img24.imageshack.us/img24/5654/bxsu.th.jpg (http://img24.imageshack.us/i/bxsu.jpg/)

if i can get 0-10c in full load, id be happy enough. im finishing working on my watercooler condensor. its taking me longer than expected to build this unit, since it must fit a tight case, so im having to get creative with that :P