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Posted

Posted request for support 17th. contacted bartx same day and equipment arrived today so superfast support and delivery 2 continents away?

All arrived in good order and evap looks very professional so time to start building.

 

bartx.png

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  • 3 weeks later...
Posted

very nice builds ? Would love to see more closeup pics of the units. What is the reason for coiling up parts of the copper tubes instead of just making them shorter? would be interesting to see closups of how you connected the instruments. I have also bought some to install in my unit.

  • 3 weeks later...
Posted (edited)

First try. only get it to -13C at present so definitely not close to what i want but then the guides i found so far are.. not so clear. Meanwhile i can also see that a lost of good knowledge is lost as sites/companies with forums has closed down. Thus guides keep linking to other resources simply not available anymore. Thus a few questions ?

1. For the capillary tube what would be the optimum length? Overall I just tried to keep all tubes short.

2. What would be a reasonable pressure on the low side when filling in R-134a.

3. I have all the tube back to Compressor covered to avoid condensation. Meanwhile I can also see that the same pipe going into the compressor is showing ice and its also forming on the compressor. To me it seems then that the coolant is wasted heading out of the evaporator or would this be normal? 

 

 

first.jpg

Edited by Matsglobetrotter
Posted
17 hours ago, Matsglobetrotter said:

First try. only get it to -13C at present so definitely not close to what i want but then the guides i found so far are.. not so clear. Meanwhile i can also see that a lost of good knowledge is lost as sites/companies with forums has closed down. Thus guides keep linking to other resources simply not available anymore. Thus a few questions ?

1. For the capillary tube what would be the optimum length? Overall I just tried to keep all tubes short.

2. What would be a reasonable pressure on the low side when filling in R-134a.

3. I have all the tube back to Compressor covered to avoid condensation. Meanwhile I can also see that the same pipe going into the compressor is showing ice and its also forming on the compressor. To me it seems then that the coolant is wasted heading out of the evaporator or would this be normal? 

 

 

first.jpg

R134A is not your best bet for single stage gas. To know what size cap tube you should use you need to list compressor specs, gas and target heat load. 

Posted (edited)
10 hours ago, Mythical tech said:

R134A is not your best bet for single stage gas. To know what size cap tube you should use you need to list compressor specs, gas and target heat load. 

Thanks for feedback. I am sure i dont have anything optimum of any sort at present but i want to try out to understand before i potentially make a change in for example the gas just to ensure i limit danger :-) while learning. With a lowside pressure of about 40psi i get around 120 -130 psi on the high side just before filterdrier when the system is on. When system is off the system stabilizes at around 40PSI on both high and low side. With that i managed to get the temp now to around -20 on the evaporator when i run a G3258 2 core 55w TDP processor. The room temp i have is around 22C.

i have access to 10ft of capillary tube 1/8 and 1/4. The compressor i have is Panasonic D66C16GAX6 which says 200 ASHRAE or  1/5HP from the supplier., the Condenser I have is stated as 1/4HP. The room temp i have is around 22C.

The Capillary tube mounted right now is 1 meter or 3.28 feet at present. 

Intermediary goal

Optimize current system using R134A so it cools maximum what is possible with the compressor, condenser and evaporator i have adjusting the capillary tube ( if possible)  and gas content to the correct levels for loads between 55- 120W TDP.

This to know that atleast the design is done correct.

Then i can empty the system including oil to chjange the refrigerant to a more effective one. (not sure what that would be)

Ultimate goal.

To run a system that can cool any processor from 55 - 200W TDP down to around -40C to - 50C in room temp of 20C. 

 

Any insights how to calculate to get there would be highly appreciated. 

 

 

 

 

Edited by Matsglobetrotter
Posted
17 hours ago, ZFeSS said:

R134a and -20C @ load is about normal. G3258 counts as idle. You need to change design when fill with another gas anyway.

Thanks. seems like I built a relevant system. It sounds a bit strange that I would need to change the design if i need to fill with other gas. That however might be the case.  Overall I request input as to what to change as per my post above preferably with enough details so the reply gives me ways forward to try. I have no problem changing anything in the system but i would like to do so systematically.

If current system is optimized -20C then what would changing gas do? would i reach -30 -40? and then what gas?

or do i need to change the capillary tube or change the length and then to what?

I could change my pump from a 1/5 hp to a 1/2 hp one in existing system using the same gas but what would the difference be?

 

Posted

I'd use a bigger compressor around 20cc, switch to either r404 or 507, step up cap tube to 0.8mm maybe even a bit bigger depending on what size compressor you go with. And if the compressor can handle it run te suction in a mild vacuum for lower temps. 

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Posted (edited)

Congrats on your first try. I also started a year ago from nothing.

First of all you have the best evap in market in a very weak unit!

You have to change compressor as mentioned before, but  1/2hp would be enough for the loads you want.

IMG_20201212_223802.jpg

 

IMG_20201212_224858.jpg

Gas r404a or r507 or r449a 

Cap tube 0.91mm and lenght 2.2 to 2.5m

With that you can achieve ~200w @ ~ -40C

Recently I finished a GPU SS :

Aspera 1/2hp 8.77cc

Condenser 1000W

20cm Fan 

2.3m 0.91mm captube

High/low side gauges 

High/low side Shrader valves 

1m Flexible 

Custom evaporator 

With those part could achieve ~  -54C on air and around -40C @ ~200watt.

 

IMG_20201209_160404.jpg

IMG_20201209_160443.jpg

IMG_20201209_155825.jpg

IMG_20201209_160606.jpg

IMG_20201128_230435.jpg

Hope I helped you a little!

Edited by Obijuan83
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Posted

Thanks Mythical tech and Obijuan83 indeed this helps a lot :-). I have ordered a bigger compressor and a bigger condenser just arrived. I have looked also at the secop site and found a software for being able to check up on what capillary tube length and diameter to use. https://www.secop.com/fileadmin/user_upload/solutions/compressor-q-and-a/pdf-files/secop-capillary-tube-selection-software.zip

Its clear also from what I have read up on various sites that my capillary tube is far to short in as much as the cooling effects and balancing is much more difficult when it is too short. The software above proposes a diameter and length in a range that seems to be more resistant to variations of load.  Meanwhile I managed to get the system down to -37C on the evaporator at a pressure of around 25 PSI on the low side.. However when running it with the test system is use I could see it would be much weaker in terms of holding any temperatures. Thus my system as is should not have a lower pressure than 40 PSI on the low side. 

I very much like the build you have done Obijuan83. I will see how I can design mine after yours. I also have the permanent pressure gauges here so will install the same when I rebuild the system.

Again many thanks for the help ? it is highly appreciated! ill be back with my new build ?

Posted (edited)

40 psi sounds high for me in low side. Propably you have it overcharged on that settings and when you lower the low side to 25psi (remove gas? more condeser flow?)you got the -37C but because your compressor is weak cannot hold loads 

The software you mention is known, but will not help in the builds we want.

 

Edited by Obijuan83
  • 2 weeks later...
Posted
On 12/14/2020 at 9:58 PM, Obijuan83 said:

You can leghthen the cap tube , but my opinion is not worth the time. Better wait for the new compressor and condenser!

i did lengthen the cap tube to 2.3 meters and now the suction pressure in general is much lower compared to before. I cant hold my old 2600K steady as it still draw too much power i guess. around 150-160W when i bench so the evaporator heats up. close to 0C

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