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Xeon th MG Pony
03-26-2006, 01:10 PM
Well I finally got all the parts I ever needed! So now it is time to BUILD! (Please keep in mind I don’t give a squat about super low temps, I’ll be happy to hold a nice +-0C constant, in fact that is my main goal is to simply keep it at a nice cool +-0C and perhaps for fun lower if I feel the need. So please no bashing or ranting at how it won’t get Über cold, I all ready know this nor do I care!)

After some help on this amongst other forums I allso gatherd the needed info! for this build

Thanks to Metze Apliences for their very generuse donation of some sweet parts!


Here's the parts list:

- Copland R-12 Medium temp compressor
- 1/2 Ton TXV American control Company
- Sporlan 1/4SAE Flare, Solenoid Valve (NC)
- Sporlan Filter/Dryer
- Sporlan Sight Glass
- Ranco Low pressure trigger
- Home made receiver


Tubing Size:

- 3/8th
- 1/4th


Evaporator:

- Helically wound 3/8th Tubing


Refrigerant:

- An Azeotropic Mix of 80/20% by Mass weight of R-134a & R-600a (This is said to out perform R-12, and is Listed as a drop in replacement)


History:

This all started when I found an old vending machine, before that point I was all ways interested in phase change, and I managed to pull the plant out of it, this finally gave me a chance to mess around with the idea. Well years later and TONs of learning I slowly started to collect parts and plot a killer build, well due to a good friend and some luck I got all I needed and being I run a Dual Xeon server what better project then to chill it!


OPERATION:

Obviously it will be pointless if I have to sit there and flick a switch one and off and it would all so be murder to the hydro to leave it running all the time! So how do I get it to cool well yet not short cycle or run 24/7?

The solution? Copy a large-scale systems way of doing it! not creative in of its self but very clever way to deal with the issue at hand non the less

Lets start at the solenoid valve, When the water gets too warm the thermostat makes a call to the Normally-Closed Valve telling it to open, this will allow liquid refrigerant rush into the TXV, the TXV then meters the refrigerant to the needed level to keep the evaporator at a constant temp.

This whole operation starts very fast, but wait! The compressor isn't running at this point! The thermostat only told the solenoid valve to open
this is where the low side trigger comes in, it sees the sudden rise on the low side and then tells the compressor to turn on! The system will run until the thermostat is happy again at which point it shuts of the solenoid valve and the suction vacuum will increase to the cut off point of the low side switch (This is because even though the thermostat shut of the valve, the compressor is still running).

The reason for this is better efficiency from the refrigeration system, any leaked refrigerant during the off cycle will evaporate raising suction pressure to the trigger point, at which the system will pump down and, while at it, further chill the water without needing a full out cycle and negate the need of an accumulator...


Work to do & Don:

So fare I need to build a Receiver, and to figure out final wiring. I have the low-pressure switch connected to a homemade L bracket and wired to the compressor.
The main thing on my list though is to get the compressor flushed & refilled with clean mineral oil as the old oil was beyond salvage. I have fabricated a ½ SAE Flare to 3/8th Copper solder connecter for the TXV to Evaporator mount.

My goal for now is to finish the Compressor Plant and have it fully oiled and wired and at a running state before I start making the evaporator. Aside from needing a couple things, yet to arrive, in the mail this is nearly complete unless I should need to replace the high side service valve as I fear I may well need to do!

and this is the sumnation of all thoughs questions I was asking! lol

Real picks soon to follow, but for now I nice MS-Paint on to hold you through!

Xeon th MG Pony
03-27-2006, 08:20 AM
Here are the rest of the pics as prommised lol

Xeon th MG Pony
04-04-2006, 12:54 PM
And Now for the lovely can tap and R-134a :) $13Canadian Dollars for 10 Onces!

Xeon th MG Pony
04-05-2006, 05:47 PM
Work Don:
I have made another Half inch to 3/8th converter for the suction side of the compressor with a 1/4 SAE flare Schrader access point and used the service valve on the compressor as a connecting spot for the low side switch as it leaked and this soled the problem impeccably simple and effective :D

I have started to think of another evap design that may offer a faster pull down but may reduce sustained load and has much more solder joints (Less is better when ever it comes to a solder joint or connection of any sort) But will offer greater surface area and way higher coil density. The receiver unit is another dead area, A propane torch tank is way over kill but I may not be able to easily acquire 2 inch pipe caps so not too sure how to proceed, but at least thanks to the good ol air duster loop hole I have 10once of R-134a waiting. I yet to order a quart of MO (I may just flush the system and go to POE) and will have to order in a coil assembly for the valve as they cost 60 fing dollars here :eek:

So the main things remaining are:
1- To setle on a final evap design & make it
2- Flush out and add oil to the compressor
3- Get a good scale and make the Gass mix
4- Make the receiver
5- Paint the system high gloss black and metalic silver :D

Possible problems:
I think my concer may not be quite big enough to handle the load so I'll have to watch closely at its temps.

Low side pressure switch (Trigger if you will)