DIY water chiller - reading suggestions?

[32 coupe]

Yes, that 15% stuff flows like butter.
It's amazing how little it takes and what a beautiful welded joint you end up with.
Yours look as good if not better than mine !

Glad to help Bruce.

Can't wait to see how your project turns out !

[guest18]

In the plumbing industry, over 30 years ago it was called silver soldering. Oxygen & acetylene  is the way to go.  In upstate NY (the Lake George region) all underground pipe had to be K Copper and it had to be silver soldered. From 1985 - 1992 one of my primary jobs was running underground supply lines from 3/4” up to 2” When silver soldering 2” pipe, lots of gas is used. In the cooler days it got pretty toasty in the trench. I stayed warm when other were complaining about the cold. But in the summer months it was brutal.

I’m not sure if it was mentioned, it’s best to purge all refrigeration lines with nitrogen before brazing.

BruceM, the joints look good.

When you do enough joints you will get pretty good at them.

[BruceM]

I like brazing with  oxy/acetylene on a neutral flame; it's a no-stink clean burn after the torch is lit and adjusted, and the 15% silver brazing rod was also a delight- no nasty flux fumes.  It flows around and into the joint as if it had flux. 

It's been raining all afternoon, lightly.  We sure need it. I'm still missing a few things but I did get the vacuum pump and gauge set.

I was able to make a 1/4 hose barb to 1/4 flare adapter with some parts Gary sent me, so I'm good to go with the Nitrogen.

[broncodriver99]

Be careful buying refrigerants on line from an unknown source. You don’t know what your getting. And here in the US it’s illegal to purchase refrigerants without the proper certification.

X2 I have heard stories of guys working on systems and finding that someone had put in either a blend including propane that mimics r-22 that was labeled as R-22 or some of the "retrofits" that are not legal here in the US due to flammability but can be bought online. Brazing on a system that has had a flammable refrigerant in it but has not been thoroughly purged with nitrogen can be a dangerous thing. There is a lot of fraud and deception going on in the trade because of the prices these days. I only buy from the distributor and the one I use is also one of the largest manufacturers in the US so it comes straight from their factory to the supply house.

[broncodriver99]

Good to know the rule of thumb. So for a 70F slab, 60F water, 50F suction temp.  For in floor cooling, too cold water will cause condensation issues at the manifolds.

That would be best case scenario. You will probably find you are closer to 15 degrees difference between each heat exchange. Depending on how the AC unit was engineered, cap tube sizing, and your slab load I don't think you will get any higher than about a 45 evap temperature, probably more like 35-40 degrees.

Nice job on the brazing. I have seen some of the young guys that can't make joints that nice after a year of "practice".

[BruceM]

Bronco-
How does the capillary tube length affect evaporator temperature assuming a modest deviation?

An elderly disabled woman friend of mine in Cornville nearly got fleeced by her HVAC service provider of years a couple months ago. Her guest house AC didn't work.  They had removed a breaker, then when called this spring about it not working, they claimed she's have to replace the condenser unit.  I convinced her to get another opinion, that guy was honest,  found the dangling wire with no breaker, replaced it and it ran fine.  The HVAC business has the same problems as any other profession.  Too many humans are sociopathic or crooked.  Makes you appreciate the good ones!

[mobile_bob]

Bruce:

at the risk of highjacking your thread... 
but thought this might be as good a place as any to get this question answered.

what kind of tech would one look for to charge an ammonia system, one that has been newly constructed and is located in a non habited building?

what does it entail?

thanks

now back to your regular scheduled programming ,,,

bob g

[broncodriver99]

Bronco-
How does the capillary tube length affect evaporator temperature assuming a modest deviation?

Capillary tubes flow a certain volume of refrigerant, it will vary slightly based on liquid pressure but not a whole lot. Depending on how much load you are dumping into the heat exchanger you will either be above or below the design parameters used when the cap tube was sized. I am thinking you will probably be below due to the lower temperature delta in your water system vs the forced air evaporator it was sized for. Not a problem, you will just run a little cooler on the suction side.

I haven't sized a cap tube in a long time and likely if I had to would track down a chart or calculator these days. The gist of it is that the inside diameter and length determine the flow rate. Alter either and your flow will change. The smaller the ID or the longer the capillary the lower the flow.

[broncodriver99]

what kind of tech would one look for to charge an ammonia system, one that has been newly constructed and is located in a non habited building?

what does it entail?

thanks

now back to your regular scheduled programming ,,,

bob g

Bob, you are going to need to find an industrial refrigeration guy, and one that knows ammonia. There aren't many of us left. Ammonia fell out of favor long ago except in heavy industrial applications due to it's extremely hazardous nature. All of the guys that knew ammonia and trained guys my age are long retired or no longer here. There wasn't really enough ammonia work around by the time the younger guys came up behind me to train them on it. I only have one ammonia account left.

Ammonia is enjoying a little bit of a resurgence in popularity due to it's environmentally friendly properties so hopefully more guys will learn how to work with it as other than the dangers associated with it is a fantastic refrigerant. These days noone does direct refrigeration with it as the safety and monitoring systems necessary are cost prohibitive but it is getting popular again in chiller systems where it can be contained in a room with emergency venilation and sealed from or away from the building it is servicing.

Ammonia can be fairly hard to get sometimes as it has become somewhat of a specialty item and not many suppliers want to stock it due to it's hazards. It has become a federally regulated substance as well. I have to file paperwork when I purchase it and sometimes the supplier has to come out and do a site inspection to verify that there is actually ammonia equipment onsite and make sure there is a safe storage area for it. I used to just go pick up however much I needed and it was no big deal.

A good starting place for a service guy is to contact the equipment manufacturer. Most of them have a network of service companies that they can recommend. If you can track down the installing contractor they may have a service department. It is a crap shoot sometimes though. Shoot me a PM with some info and I will see if I can give you a hand.

When you say charge, is this something that has been built but never commissioned or was there a failure and the ammonia released?

For the sake of Bruces water chiller thread we can discuss in PM or maybe in another thread if it is of interest.

[mike90045]

The IcyBall is a wonderful device, and I've dreamed for some time, of re-creating one out of "parts" .
But I don't have the skills to pull it off, but such an elegant design.

http://www.crosleyautoclub.com/IcyBall/crosley_icyball.html

[BruceM]

No worries.  I've been using an ammonia refrigerator/freezer for over 10 years so am interested.

While my Ammonia fridge was still under warranty, it sprung a leak and quit cooling.  I had to replace the whole ammonia unit with a replacement myself, quite a chore.  It's been fine since, zero noise and zero load on my battery bank.

I got the refrigerant reclamation tank late today and used the pump and gauge to put a vacuum on it.  It got dark and rainy so I stopped, but will continue that tomorrow.  Hopefully I'll make some real progress tomorrow; like getting the window unit evacuated and the stock evaporator and blower removed, valves installed, etc.



 

[BruceM]

I was able to  capture 1.1 lbs out of 1.25 lbs faceplate charge (20 oz) of R-410a using the 12000 BTU window unit compressor as the "recovery pump", with the well evacuated recovery bottle in a bucket of ice water connected through the gauge to the high side bullet fitting. 

I had gauges on high and low side via bullet piercing valves.  They worked and didn't leak. I'll remove them and silver braze the holes after adding Schrader valve stems.  If I was doing it again, I"d skip the high side gauge and second hose, and hose direct to the tank, and watch the low side for pressure going to zero.  That was the limit for my pump, with the high side about 105 psi.  It just couldn't do more. About 3 minutes of compressor and fan run time. I could have stopped sooner but kept hoping it would pull a vacuum.  Once low side was 0 psi, it could do no more, so I closed the tank and shut down.  My vapor pressure equalized in the system at 50psi after it sat.

I think that's not bad for no recovery pump.  I don't know if a refrigeration compressor will do any better.  I've read most recovery pumps will pull low vacuum, while still delivering high pressure to  the tank.  That's impressive.

I was able to remove the stock evaporator and cut the evaporator side motor shaft off after removing all the plastic and cast bead board.  I re-routed the high and low side pipes as I want them both coming in compressor side. The photo shows the unit stripped down to it's condenser unit function.  The condenser fan shroud was shifted out of the way for some brazing of new schrader valves, which comes next.  The brazed flat plate exchanger is in the rear of the pan, and the capillary tubes are on the left of the pan.

The electonics have been removed and replaced with one switch each for fan and compressor.  It was a breeze to reverse engineer this unit's electronics, since the motors are induction type.

I'm beat but happy about the amateur, low budget recovery.

[32 coupe]

Looks good !
I was expecting the plate cooler to be much larger.

[BruceM]

Back on the project today.  The refrigerant to water exchanger is installed and plumbed so that it drains any liquid and oil to the outlet, and it's slightly downhill all the way to the condenser unit.  You can see the capillary tube coil near the insulated exhanger.  I had to make one new end, by cutting the tubes and brazing them in a slightly flattened 1/4 tube. The service valves are now brazed in on the "stripped to condenser unit" (thanks, Gary!).

I am included a picture of the small nitrogen bottle my neighbor rented for me.  Paperwork says $6 rental, $18 for the gas. I'm using a cheap argon flow type regulator/ valve.  Just enough to have the ball spinning and not lifted seems good by the finger on the end of the pipe method.  I can either slide the 1/4 hose on copper and clamp, or use my AC service valve adapter which I made with one of Gary's valve stems soldered to a brass hose barb.

Outdoors, I picked a spot and leveled it with some sand, and laid some 8"block caps.  I wanted to raise it just a little to avoid flooding it when we get torrential rains, but keep it low enough for a downhill run from the evaporator.

I've got to do some sheet metal work for a protective case,  otherwise, I'm ready to hook the outdoor unit.
The stock housing has zero protection for the condenser, so I've got to do some redesign for a ground mounted unit.
We're having a new heat wave so I'm hurrying to get it hooked up for testing.

Best Wishes
Bruce

[broncodriver99]

When you plumb it to your floor make sure the slab coolant and refrigerant flow oppose each other. You want the warm fluid coming from the slab coming in to the refrigerant vapor end of the HX.