Recirculated water cooling system discussion

[rumsponge]

1-overview.jpg

Got myself an old aircon (6.8 kW) and started converting it into a recirculating water cooler. Stripped the electronics and rewired the fan to 240 AC. - working fine.
Will do the re-plumbing and removal of the compressor tomorrow. Really excited how this project will work out. the condenser is massive - I calculated there is 40 meters of copper cooling pipe in this monster 8-}

[WalterWhite]

1-overview.jpg

Got myself an old aircon (6.8 kW) and started converting it into a recirculating water cooler. Stripped the electronics and rewired the fan to 240 AC. - working fine.
Will do the re-plumbing and removal of the compressor tomorrow. Really excited how this project will work out. the condenser is massive - I calculated there is 40 meters of copper cooling pipe in this monster 8-}

Would love to see a build thread for this mate .... I just picked one up two days ago and will be doing the same ... Mines a fairly new one though so already 240AC luckily saving me the wiring issue

[rumsponge]

will do mate. just realized that because of the transport the compressor oil is everywhere in system. :? will have to rest it for a a few days, so probably not until next weekend.
cheers rs

[scythe]

Watch out if it still has refrigerant in it, you dont want to get that on you, so be careful bleeding the system if its not already empty.

[rumsponge]

Yep, it is still pressurized. I will get an air con technician to pump out the remaining R22. The guy I got the unit from said there shouldnt be any gas in it :teasing-blah: :angry-banghead:
well, at least the good news is that the system is not leaking :dance:

plumbing_2.jpg

[rumsponge]

Ran into another problem with my A/C cooler.
Had the aircon tech guy pump out the remaining R22 (turned out it was only tiny amounts of residual R22, pumped for 1 minute, charged me $80 :sad: ).
Used my trusty hacksaw to remove the compressor (heavy) and now have 1 inlet copper pipe (OD: appr. 5/8") and 2 outlet pipes (OD: appr. 3/8").

DSC00055b.jpg

Now, here is the question and problem. how do I connect this neat and tidy to water hoses ? Went to the green shed looking for compression fittings but nada (only two sizes neither of which fit). Went to Reece, but they didnt have anything compatible either, but suggested a refrigeration specialist.
I am sure I can plumb something together with various hose adaptors, but its not excatly tidy (may go down this road for testing). I was considering soft soldering it (if I manage to get the couplings) and then finish it with a 3/4" garden hose adaptor.
Any other ideas ?
Cheers, RS

[Hardie355]

Get some 3/4 copper straight over the 5/8 anneal squeeze a bit with multi grips and solder on then put a brass 3/4 tube bush on to attach garden hose fitting. As for the other side I would get 3/4 drill a couple of holes in then crimp one end and solder that with a tube bush as well. mind you I would hate to try with soft solder, im going down the same path and will use silver solder.

[rumsponge]

Thanks hardie,
Great ideas.
cheers RS

[scythe]

What about cutting the outlets off at the "y" pieces just a little further back?
They look about 3/4, might be easier to work with.
For the inlet i would see if the Frigies have a reducer from 3/4" to 5/8", they probably will and hopefully less than $10.

http://www.westaflex.com.au/refrigeration/copper-fittings.html these guys do so im sure your local fridgie will as well.

[GroggyAl]

RS, 1/2" copper tube fits nicely to both the 5/8 and 3/8 tubes. I silver soldered mine. You may have to bell the ends of the the tube out to get a good fit but it works fine. No need for expanders. From the 1/2" tube go to the garden hose connectors outside the casing. I have my tank (and pump) inside the unit and my return goes straight into the top of tank. This keeps it all compact. Are you going to combine the circuits or keep them seperate?

[rumsponge]

Thanks all,
this gives me a few options. GroggyAl, my unit has 4 circuits. inlet flow (5/8) is divided into four 3/8, then the 4 outlets are joined to 2x 3/8 outlets. I was planning to use all circuits initially and modulate cooling capacity via fan speed (will probably do some testing using mains hot water before installing anything permanent). I think MeatheadInc's setup uses separate circuits for pump bypass and return from PC/RC, but not sure what the advantage is.
Also havent decided on internal or external reservoir. There should be enough room for a 10-20L reservoir where the compressor was, but in the moment I am favouring an external larger reservoir (60-200L).
Thanks again,
RS

[GroggyAl]

RS,
An external tank is simpler and you don't really need a big volume of water when you have plenty of cooling capacity. An internal tank can be more dicking around but it reduces head losses and makes a compact self contained unit that you can mount semi-permanent or put on a set of wheels.
I ended up splitting mine into two separate circuits to reduce the pressure drop in the overall piping system. I use one circuit for the main RC cooling and one for the pump bypass. I want to eventually revert back to a smaller pump and do away with the bypass piping completely (KISS principle).
You will love the cooling capacity these coolers have :-D Shame about the cost you had to evacuate the unit x_x

[rumsponge]

Thanks again Al,
Your advice is greatly appreciated. Just realized you are running a 2" BOKA (without PC ?). I am planning to hook my AC cooler up to a neutralizer with product condenser and cant imagine any scenario where I wouldnt be using a PC. Do you see any problems running the PC at full flow at all times without a dedicated pump bypass (I dont) ? Probably also have to start thinking about a pump. with your setup (I assume it is a similarly sized AC cooler) and your 750W pump what sort of flow rates do you get if you run all circuits of the AC ?
CHeers, RS

[GroggyAl]

Thanks again Al,
Your advice is greatly appreciated. Just realized you are running a 2" BOKA (without PC ?). I am planning to hook my AC cooler up to a neutralizer with product condenser and cant imagine any scenario where I wouldnt be using a PC. Do you see any problems running the PC at full flow at all times without a dedicated pump bypass (I dont) ? Probably also have to start thinking about a pump. with your setup (I assume it is a similarly sized AC cooler) and your 750W pump what sort of flow rates do you get if you run all circuits of the AC ?
CHeers, RS

RS,
We could probably dedicate a separate post on this subject but firstly a simple answer to your question is 'No you shouldn't need to run a pump bypass if you are always running your PC at full flow - PROVIDING you don't have too much restriction in your piping system.
If your pump doesn't have the required head you may need every bit of pressure you can get out of it anyway. It's not advisable to run a centrifugal pump at close to 'dead-head' conditions but they are quite forgiving. With my 2" Boka I have a lot of line losses (restrictions) in the 1/4" tube RC, hoses and PC so I need a lot of head. A 350w Ozito submersible pump produces only 5m head and the 750w Ozito produces 8m maximum head. They have great flow rates (7000 & 15,000 L/hour respectively) but that's at zero pressure so it's useless to us. They need more head - we all do :-p

I just love head :)) so I use a 350w Commercial Electric submersible barrel pump which produces 10m head. It's only rated for a maximum open flow of 3,000L/hour but that's an overkill for our needs. I needed the extra head for my Boka but I'm hoping to be able to get away with a smaller pump with my new build if I can design it with minimum restrictions. That may mean running two of my radiator circuits in parallel to reduce the pressure drop. Less restrictions + efficient heat exchangers = smaller pump. :dance:
Sorry for the long winded response but flow rates will be dependent on line losses in your overall piping system and the head your pump can produce.
Cheers
Groggy Al

[Sam.]

This has been split as suggested, some good info in here let's keep it going :handgestures-thumbupleft:

[rumsponge]

Thanks GRoggy and Sam,
I ran some tests today to check if my AC cooler is suitable for my intentions and hooked it up to our hot water mains system using some cheap hoses and clamps.

DSC00065_web.jpg

(note for myself, make sure the missus is not at home next time) :violence-smack:

I measured flowrate with a kitchen scale and timer and temperatures with an instant-read digital cooking thermometer.

My AC radiator has 4 cooling circuits and for this test I ran them all in parallel (connected the 5/8 inlet to a 16mm hose and the two 3/8 outlets to 10mm hoses each).
When the AC cooler is not connected (no resistance to flow) the mains hot water flow was 2.7 L/min (temperature 53.2 C). When I connected the AC cooler, the outlet flow (after waiting for 10min to equilibrate the system) was 2.5 L/min and the outlet temperature was 30.3 C (ambient temperature was 28.8 C).
So at this flow rate a drop of over 20 C and within 2C of ambient. Fan was on high speed at all times. :handgestures-thumbupleft:

When I cranked up the flow so that the outlet is about 8 L/min, I still get a temperature at outlet of approximately 35C.
So very happy with these results so far. I believe 2.5 L/min is plenty and with a 200L reservoir should be alright.
My FSD neutralizer hasnt arrived yet, so the next test will be with all the gear attached and a water pump.
I would be interested to hear at what cooling water flow rates other Neutralizer users run their gear ?
Cheers,
RS

[rumsponge]

just for reference, here are the details of my ac radiator:

Fujitsu Model AOT24RNBL
Cooling Capacity 6.8 kW
Heating Capacity 8.0 kW
power input cooling: 2.6 kW
power input heating: 2.7 kW

[WTDist]

(note for myself, make sure the missus is not at home next time) :violence-smack:

as soon as i say it was the kitchen first thought was hmm is he single... if not he is now :laughing-rolling:

[GroggyAl]

(note for myself, make sure the missus is not at home next time) :violence-smack:

as soon as i say it was the kitchen first thought was hmm is he single... if not he is now :laughing-rolling:

RS you are braver than I am :))

I don't have a neutraliser to give you operational data but tomorrow I will hook up my new RC & PC and let you know pressures, pressure drop and flow rates through my recirculating system/ condensers for you.

Getting within 1 or 2 degrees of ambient is all you are going to get (but that is fine if you have a good flow rate). Did you have the shrouds/ covers on when you did your tests. Directing the airflow with the shrouds will improve things even more.
Cheers
Groggy Al.

[rumsponge]

hi Groggy,
I didnt use the shroudes and cover, yet and looking forward to your measurements. I bought an ozito 550W pump today and hooked it up to the cooler. I cant measure the pressure drop, but the outlet flow was approximately 15L/min so plenty of room for connecting a lot more gear (which will have further impact on flow rate), The pump is rated at >200 L/min (no restrictions to flow) but when I connect a 25m garden hose (12mm) all I have left is approximately 20L/min. I guess the advertised flow rates are just a marketing joke which were obtained under lab conditions.
Anyway, now I just have to wait for my neutralizer to turn up and see how it will work with the cooler. But I am quite optimistic that with gate valves at the PC and RC and several options for hose diameters I will be able to get decent results, flow rate and cooling capacity.
Gives me time to look into more permanent modifications to the cooler and also have to work on my elements and controller.
Cheers, RS

:text-thankyoublue: