My R290 water to water HP
 

Well, here is the HP mostly brazed up. My fridgie friends warn me against having the unit indoors. I am not sure I believe them but I have my niece living close to the boiler room so I think I will put it outside anyway. There might be a bit too much noise.

The condenser will be placed indoors so I don't have any water outdoors and I will pressure test it with nitro to 400psi so there should be no possibility of a leak indoors. The Evap (on the left of the pic) is connected to a pump and then to a big air coil which will also have a solar thermal input. This will heat up the 1000L open tank shown in another post.

Really,really double check the pressure ratings on *all* your bits before you do that. We don't want a picture of you wearing your compressors outer shell as a hat.

400PSI is 27.5 Bar. Are you positive your HX and more importantly receiver and compressor shell rated to 30 Bar?

The HX is certified higher than that and I will only test the HX and a few fittings. Maybe 400psi is a bit excessive anyway. 300psi should do it.

Since no one has said so, I will take it on myself to say what a nice job you are doing.

I'd like to see more photos, from different angles. It would be great to see your good work 'in the round'.

Please say more about the components you are using, even tube size... everything. And how you came to choose the particular components that you are using.

The more information we can bring out, the more useful this site will be.

So what will be your water source? Well? Lake? River? Loop field?

Also, that's a nice, healthy looking HX you have there.

Just a cautionary word... I realize that you may have taken care of this already, but I had some problems with using a similar HX, in that mine had MPT connections all around, and I had used an adapter that wasn't a taper thread on the gas side. It held for a while, but eventually started leaking. I haven't gone back to deal with that one. I asked about the problem at my local HVAC parts place, and they recommended switching to an adapter that had FPT (tapered) threads AND using some kind of special 'pipe dope' that folks in the HVAC trade use. I don't know from personal experience how effective that stuff is.

But I have seen some killer deals on HXs that had pipe thread all around... I contemplated the possibility of brazing an adapter to the inside of the MPT fitting, and going with brazed connections everywhere. I have come to really trust brazed connections and to be wary of flare and threaded fittings. On my next HX I made sure that I had sweat (braze) fittings on the gas side and MPT on the water side.

Keep up the good work, you're off to a good start!

Best,

-AC

Like Randon, I have a full machine shop so I can fabricate most things. Many people will use Rotalocks (special threaded fittings) for refrigerant connections to the pot or some other components but I prefer to have a brazed connection. I am a bit concerned that the startup torque of the pot will cause a brazed fitting to fail but I'll wait and see. Maybe a soft start will solve it if it does.

I had an opportunity to buy some Chinese HX for a good price but decided to spend a bit more and get some that are certified. Side bar here, I lost a bid to put a solar water system on an apartment building and the winning bid promised the moon. In the end, they brought in all Chinese, non-certified components including plastic pipe for pressure piping and covered it up before inspectors could see it. They had to limit the solar temp to 140 as the pipe would not take much more and eventually it failed. Sometimes you get what you pay for.

Anyway, the HX is entirely brazed on the fridgie side and on the other side, I have gasketed unions which are REALLY common on anything European as they seldom use a tapered thread for water or boiler lines. I will take some pics later today if I get to the shop. I am using corrugated stainless steel tubing to run to the loads which will provide vibration dampening.

Here are a few more pics. The two tanks are a hot and cold tank for testing the HP, one on the evap and one on the condenser then I can check the optimal flow rate on each side.

The evap is actually attached to a glycol line that goes between the plate HX and a big outside coil. I will inject into this some solar heated glycol to try and improve the COP when the heat is available.

Attachment 2877

Attachment 2878

Attachment 2879

Attachment 2880

The fittings are actually two unions, one for the HX and a reducer to bring it down to 1.25" for the tubing. There is a fibre washer on the union (not shown)

My family and I visited Mikesolar's shop. Very nice and he's doing a very excellent job on his heat-pump. But I think he's keeping some of his trade secrets close to his vest. I think he's becoming like the rest in the HVAC field. No, just having fun!! It looks very nice and we're all looking forward to his results.

Keep up the good work Mike

Randen

Thanks Randen,

I'm not keeping things THAT secret but I also don't know if it will all work properly and my controls strategy needs fine tuning so I wouldn't want to steer people in the wrong direction. It is great fun and you will get to see a running log of the outcome once I have figured out how to do it. :D

All you guys are inspiration regardless.

That is a beautiful job you did with that. Can I ask, Is that a receiver in the middle and what are the 4 small components on the left? Check valves? I'm curious how this project is going. Good work!

It is an accumulator with a pancake HX in it. The 4 small checkvalves are there to direct the flow through the subcooling valve in always the same direction even when in defrost. The beast is still there while I get my control system worked out (taking way too long)