A new Chiller Project! 11,000 BTU

[JWB]

Hey Sean,

no the 220mm fans you see were the ones that werent good enough. In the last pic bottom right you can see a desk fan. I've got 3 of them on full which works lol. So I use them for now, otherwise I will have to put 12 120mm fans and connect them to a psu just for them lol!

James

[hello im sean]

How can you tell if the condenser coils are getting sufficient cooling? How did you gauge its point of best efficiency to know the 220mm fans weren't enough and that the desk fans are..? Thanks

[JWB]

Well the condensor was at around 70C and it wasnt pulling the temperatue down very fast at all and not as low. I also checked the subcooling which was more than 15F difference. Thats the temperature difference between the entry in to the condensor and the exit of the condensor. Even now with my 3 desk fans on full the room heats up quicly. The reason its getting that hot is because the unit was desinged as an aircon it has a lot more charge than is needed for a chiller. In a month or so I'm going to lower the charge with a piercing valve I think

James

Edit: The desk fans are faaaarrrr more powerful than the 220mm fans. they are ok for a case fan but no where near enough for this condensor. remeber this is a 11,000btu unit too.

[ericFX1984]

The reason its getting that hot is because the unit was desinged as an aircon it has a lot more charge than is needed for a chiller. In a month or so I'm going to lower the charge with a piercing valve I think

is that kinda like how when an air conditioner is underchanged it can freeze the evaporator?

[JWB]

Hmm sorry eric that could be a number of thing, even as simple as the fan has stopped working!! Don't get me wrong though I'm not much of an expert :S. I do know that air conditioners are charge to cool a large a area (a room for instance) to a lowish temperature. To cool a small high heat load area like the cpu to subzero temperatures you need less of a charge. From what I understand this is because the condensor has to get rid of a lot more temperature than is designed for so the liquid freon will build up in the bottom of the condensor and will leave much less room for the unit to cool the rest of the charge.

The procedure is to fit a piercing valve to the small copper/brass tube coming off of your compressor. Its the one that is pinched off. If for some reason you havent got one then I have read straight after the compressor and before the condensor is the right place as well. Once you have the piercing valve hook it up to a set of gauges and an already vacuumed gas bottle. While the unit is running let a little bit of freon out of your system by turning the piercing valve the opposite way to piercing. or the valve may have a little tap on the side of it on some models. Once you have let a little bit of freon out leave shut the valve again and wait 15 min to 30 min and see if the temperature drops. keep doing this little by little until the temperature rises slightly. This means that you have gone too far and that your system is charged correctly. While doing this the system should be under load, because you are tuning the system to run the best temperature for the load you are running. When you take charge out of a system you may be lowering the temp under load but you are also lowering how much load the unit will be able to take overall.

this is what I've gatherd from these forums over the years. So if I'm wrong anywhere don't hesitate to tell me

James

[JWB]

Jamal, are you ready for the next step?



We can do better. Since this system is charged for a much heavier load (A/C), it now has too much refrigerant in it. Your next step is to get a piercing valve and a set of guages. Install the piercing valve on the process tube. That's the stubbed off tube on the compressor.

Run the system until the coolant is at its lowest temperature (under load). Put your low side guage on the piercing valve. Then remove a little refrigerant, wait 10-15 minutes and see if the coolant temperature drops. Keep doing that until the coolant temperature stops dropping. This is the optimum refrigerant charge for the load. If the coolant temperature rises, you have gone a step too far.

Keep in mind that if the low side is in a vacuum, you must shut it down in order to remove refrigerant. You don't want to suck air into the system.

Heres where I got some of my info from the master GaryLlyod lol. really wish he was still around on the forums. COME BACK GARY!!!

James

EDIT: The actual conversation is on page 8 of the sticked Pimpsho thread (can't remember the name). Chiller guide or something like that. Its really good for learning about chillers. I have read it hundreds of times lol....sad :S

[ericFX1984]

Heres where I got some of my info from the master GaryLlyod lol. really wish he was still around on the forums. COME BACK GARY!!!

James

EDIT: The actual conversation is on page 8 of the sticked Pimpsho thread (can't remember the name). Chiller guide or something like that. Its really good for learning about chillers. I have read it hundreds of times lol....sad :S

mine is doing prett good so far, pulls to -24c in less than 30 mins

[hello im sean]

When you say the system must be under load when decreasing pressure. Does that mean use the piercing valve while the evaporator is pulling the liquid in the res down from room temp? Or should I wait till it bottoms out and then lower pressure..? Also the the condenser require less cooling (quieter fans) with the pressure dropped?

[JWB]

The piericing valve should go on the access pipe on your compressor or one the pipe between your compressor and condensor. The reason is this is the high side and means the compressor will force the gas out of that side. About the condensor that should be right because there will be less gas for the condensor to cool back in to a liquid. What you should do is hook it up to your computer and overclocking it to what you want. Wait until the temperature of the system is at its very lowest and the take a small amount of charge out. Wait 15 minutes and the temp should have lowered. Keep doing this until the temp rises instead of lowers and you should be there . Althoguh this is the one thing I have done yet. Its what I've read so checking with one of the phase guys first would be best. Its something I am thinking of doing soon though. My dad used to be a plumber you see and has used piercing valaves on water and gas hundreds of times.

Heres a link with Kayl from the forums explaining how to do it.

http://www.xtremesystems.org/forums/...p/t-36699.html

I also think pull down will be faster as well after doing this, but gary always used to say make sureyour chiller is full built etc first and you have it under the load you are wanting to cool.

Hope thats some help

James

[hello im sean]

Deff helps man! Will the cooling capacity drop very Significantly though? im also running a 11,000 btu rig

[JWB]

Yep thats what your getting rid of, the capacity. So for colder temps you are trading more waterblocks. Lets ssay as an example a unit could cool 700 watts to -30C you might get 500 watts at -45C. As an example

[hello im sean]

Is there a math equation I could do...?

[JWB]

Well every unit is differant but i'm sure there is some way of working it out. How many btu's your unit is, the heatload, amoung of charge, charge type etc.......Unfortunately I don't know what it is myself though Sean.

James

[hello im sean]

Hmm considering I was thinking of getting one of these portable a/c units to build a second chiller in my dorm.. what are the rough dimensions of your unit with the cooler installed? And is it a lot quieter than traditional window units of around the same btu..?

[JWB]

Well because its vertical and uses the frame from the original AC unit, its very portable. I just wheel it to where I am going to bench. I'd say its 3 feet high by 16 inches by 14 inches. Its pulldown has dropped from my first test, maybe because of my room being cooler. Although the main problem with it at the moment is the pump I have an ehiem is only producing a trickle. So today I should have arrive a pump that is 5 times as powerful. Its a 3,000 liters per hours pump so I'm hoping for some great results! Even with the current trickle and I mean trickle my cpu (opteron 144) that I've got in my benching rig. Unloaded I can can get -5C and 100% loaded it drops to -1.5C. The trickle is that small though i'm suprised that the temps arent like 60C lol. My temps are taen with a fluke k type probe attached to the IHS

James

[ericFX1984]

you are testing on a OPti 144? nice


on my Phenon II 965 BE @ 4.4GHz I see 7.5GHz on full load

as for the unit pulling down faster... i too have noticed that... my unit pulls 6 gallons from room temps to freezing in just under 20 mins, originally took my unit an hour nearly

[JWB]

Hey Eric!

7.5GHz!? I'm guessing -7.5F??? I am going to order some dry ice earlier next week I think, so I will be able to finnaly test how cold my -65C windshield fluid actually goes too. I bet its not -65C lol! I can't have any complaints with it though because at -30.7 its not even starting to gel up . I'm just waiting on royal mails right now for my pump, was expecting it yesterday........my current pump is great for normal water cooling but the trickle it produces at minus temperatures is just stupid. i have to get it going then drop the temps because if I drop it in at say -20C it just refuses to turn on :P

James

[ericFX1984]

Hey Eric!

7.5GHz!? I'm guessing -7.5F??? I am going to order some dry ice earlier next week I think, so I will be able to finnaly test how cold my -65C windshield fluid actually goes too. I bet its not -65C lol! I can't have any complaints with it though because at -30.7 its not even starting to gel up . I'm just waiting on royal mails right now for my pump, was expecting it yesterday........my current pump is great for normal water cooling but the trickle it produces at minus temperatures is just stupid. i have to get it going then drop the temps because if I drop it in at say -20C it just refuses to turn on :P

James

lol yeah that's what i meant

[JWB]

Well a mini disaster for me today. I did actually receive my pump today which is a beast! Its about 4 times bigger than my last pump is weights 1.5kg. 3,000 liter per hour. Anyway Ive spent all day trying to heat and then stretch my 1/2" tubing to 3/4" so it will fit on the pumps fittings. Without success I tried something different and got it all working and it was about 5x the trickle I was getting. The disaster? well the new pump was on and I decided to move it a little because it was buzzing on my res wall. Next thing BAM! Pipes out I get hit in the forehead with coolant and before I can switch off the pump (Literally took 3 sec) a 4 to 6 foot fountain of water everywhere. Above 3 liters of coolant now adorns my room. I've just finished cleaning up now, reek to high heaven and have had to keep the door and windows wide open because you could probably get high just by walking in LOL. BTW my GF home in 25 min!!!

[ny_driver]

Ohh dude. Too much restriction in your water-block and you must use hose clamps on the intake side of the pump.

I modded my Apogee XT into a much higher flow Apogee XT last night...it was simple. I removed the inner O-ring that is there as an intentional restriction, drilled out the intake hole to match the outlet hole, and then took a die-grinder with small disc and cut 4 grooves in the block to allow much more water to get through and it worked great.

Look at the flow now.

[hello im sean]

Hey I was wondering since you used a portable a/c unit. Is the final build any quieter than when using a window a/c? Or what advantages/disadvantages do portable a/c's for water chilling have?

[JWB]

Well its an 12,000 btu unit which means its 1hp (well the sticker says 11,000 btu) so its quite a big compressor. But I have to say it not loud at all! The 3 desk fans I was using to cool it was slightly louder actually. The great thing is though because its built vertically I just wheel it where its needs. I took all of the plastic sides off for better cooling but you could leave them on or board it off and still manouver it about, but it be a lot quieter

[hello im sean]

Hey so it looks like the condenser fan was sandwiched between the evap and condenser and it would pull up air and blow out the side. Seemed like a good method why didn't you keep the bottom panels and fan for the condenser? Instead of stripping it down and replacing it with bulky external methods (3 desk fans)

[JWB]

Yep your right thats where it was. In one of my first posts i put a link to a pdf so you can see what its like in full. Well quite a few reasons for removing it. Mainly the resovoir wouldnt have fit underneath the evaporator if i kept the section where the fan was, It was VERY VERY loud and lastly didnt move that much air really. About as much as one desk fan The fan was an cactual cone shape and if I moved it out of its specially shaped plastic section it would just spin the air around it and not move it in any particular direction. I have two motors from the fans left though that I may attach a blad to sometime in a later build

James