12.000btu a/c chiller

[oc_nightmare]

hi
after converting this r12 dehumidifier to a waterchiller, i started something new and more powerfull than a simple dehumidifier.....

i spent 3 weeks looking in all junkyards around the town and i finally got something i new that it had potential

after spending some €€€ i came out with this:


after spending more €€€ in some tools,


and these pics have been taken today after the hvac tecnic leave:





i have a question:
is the compressor suposed to be so cold (frozen)? isnt to mutch freon in the sistem? he said that it is good for the compressor cooling

btw, isnt r22 suposed to boil at ~-40ºC? what can i do to improve the temps?

cheers

edited to display pics..

[pythagoras]

TURN IT OFF AND TURN IT OFF NOW!

Sorry for the caps lock, but that compressors has minutes of life left.

Regards

John.

[Gary Lloyd]

How many watts heat load are you planning to cool?

What size is the cap tube? Is it the original cap tube?

Did you have the system recharged with R22?

Fill the res before you do anything else.

[chilly1]

I think your capillary tube is also too large/short. What is the ID (Interrior diameter) and the length of the capillary tube.? You also may need more evaporator surfae area for a 12000 btu heat load. What will you be cooling?

The main danger is floodback and liquid slugging. It appears that you may have come dangeriously close. If the original system had a suction accumulator you may want to put it in th ecircuit if not please install one, to size the accumulator determine the total system charge and get an accumulator that will contain that amount within a comfortable margin say 80% and this will prevent floodback nearly 100%. In the mean time fill the Rez as gary said. Get the thing under load...

[Pimpsho]

ya im suprised that compressor is still working...its basically killing itself

[Blergo]

WOOO!!! suicidal compressor the compressor on my waterchiller (made from a dehumidifier) used to get like that till i pinched the cap tube a bit. ofcourse i never ran it for long like that, just to test and see if it had stopped iceing.. :/ it now ices about 2" away from the compressor and has been running 24/7 for about 9 months without any problems it has a thermostat from an old freezer set to -10 though so the compressor cycles on and of (between about -5 and -15 i think) anyway, good luck mate
owen

[iceman2g]

oc_nightmare I was having same issue with my compressor getting frosty. I don't plan to run it until i get it sorted out, like Gary and chilly1 said your going to shorten lifespan of compressor drastically.

Blergo how could does your chiller get?

Gary Lloyd would shorten cap tube help with the issue he's having.

[oc_nightmare]

the cap tube is ~1m of 1.2mm.... i tried 2m of 0.7mm but the hvac tecnic said it was too restrictive and the evap wouldnt have enough freon to cool the metanol.....

i havent tried to test it under load to see if the frost reached to the compressor.

the evap is 9m long....


wednesday im going to test the sistem under load and then ill post what happens.... if i let some r22 out could the system get healthier?


thanks for the help

[Gary Lloyd]

the cap tube is ~1m of 1.2mm.... i tried 2m of 0.7mm but the hvac tecnic said it was too restrictive and the evap wouldnt have enough freon to cool the metanol.....

On normal systems, we want fast pulldown and shutoff, so we size the cap tube to the compressor. These are not normal systems. We want lowest temp, and screw the pulldown time, so we size the cap tube for the heat load.

Your A/C tech is sizing for a normal system. The size he has chosen would be just right if you wanted to get the water to about 0C and then shut off. But you want it to get as cold as possible, so you want a much more restrictive cap tube.

1.5M of 0.7mm cap tube would be just about right.

wednesday im going to test the sistem under load and then ill post what happens.... if i let some r22 out could the system get healthier?

Yes. Definitely.

[oc_nightmare]

will do

thanks


only one more thing: what kind of temps can i expect from a system like this @ cpu load?

[Gary Lloyd]

My crystal ball is cracked. Should I say -20C under load, so you can be pleasantly surprised, or should I tell you that it will do -50C under load, because I know you would like to hear that? I will go out on a limb and confidently predict that it will be between those numbers... LOL

[Blergo]

Blergo how could does your chiller get?

i was geting about -18*C load temp, i need to change the cap tube on it i think. cant be bothered at the moment though as i am in the middle of building a new one YAY!
owen

[Blergo]

it looks to me in those pics like you have twisted the wire comeing from the chiller onto another laed with a plug?!? all i can say is DONT! go to the shop and spend a couple of euros on a proper conector or plug! twisted joints can have fairly high resistances and have been known to heat up enough to set fire to stuff.. :s or solder them together and insulate them thats if you havent already done so or mabey im just not seeing the conection right in the pic's.. either way, if your going to do somethign do it properly.
owen

[oc_nightmare]

LOL gary

blergo those wires were just for testing.... soon i will solder it to a real plug
thanks for the advice

[Blergo]

good good... just be carefull and dont kill yourself before its finished ;-) you can do that afterwards if you like.. but not before :p

[oc_nightmare]

hehehehe

i will try to

[oc_nightmare]

after some testing and letting some freon out, it just hit -32ºC with 20l of -37ºC antifreeze on it..... after two hours working, it only made frost in the suction line about 10cm from the compressor

i only have the pics on the cell phone, didnt take the cam with me
in saturday ill take pics and try to test on cpu load

cheers


btw, i have a eheim 1046.... do u think it can handle the load at these temps?

[oc_nightmare]

after some cap tube tweaking,





i havent any neoprene to insulate the wb... ill try to find some on this week


ps. sorry for the size of the pics

[kayl]

well done, what sort of tweaking did you do to the cap tubing?

[oc_nightmare]

kinking

[kayl]

is there any chance of some pics,
i tried this on my airconditioner but had no luck, i only did about 5cm though, and i really needed to let some R22 out as well (as you have done), but had no piercing valveor gas tank at the time

[oc_nightmare]

today ill see if i can get any pics... the a/c isnt here..... to loud to fit on an apartement..llol...

[oc_nightmare]

kayl here it is...


and here is the insulated wb: