Quote:
Originally Posted by stef110
thanks for the explanation...stef
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This is an interesting project you have here. I have a nearly identical project that hasn't received the attention that I need to give it. My project isn't to combine solar with an Air Source Heat Pump, but rather to combine an Air Source Heat Pump with a small Ground Source Heat Pump. Really very similar indeed!
Your brazing job looks great to me! Good photo of the inside of the brazed tube... evidence that you got it just right!
One concern I have is that it looks to me like you are attaching your gas tubes to your Brazed Plate HX, with some kind of threaded fitting. I did this also, on an older project, and it ended up leaking gas & oil at that threaded connection. It was a slow leak, but over time, it leaked. I can't tell from your photo, what kind of threaded connection you are using... you may have a threaded fitting that is properly designed for the rigors of refrigeration service, but from my experience, this could be a problem point.
Here is a photo of my solution, which is to buy HXs that have fittings that will accept brazing on the gas-side connections, and use threaded-connectors for the water side connection. Your setup may work just fine as you are doing it. But should you discover that they leak, you can still braze to the threaded connector, if you braze to the
INSIDE of the threaded connector, if the are not threaded. In that case you will need to be very vigilant to clean all the refrigerant oil residue out of the HX before you braze.
We also have another EcoRenovator, named Randen, who has had difficulties with the threaded
water-side connection... in that he tried to use US/Canadian pipe thread connectors, but it turned out that his HX used British pipe thread which was slightly different... and just enough to leak water. This forced him to make custom adapters, but since he is an experienced machinist, he was well-equipped to do this. Hopefully, you are in the Metric world and these threading systems are standardized, and you'll have no problem.
I'm curious about the capacity (size) of your HX? It looks good to me, but I'm curious how you went about determining the capacity (size), and also what capacity (size) you ended up choosing.
I'm also highly interested in the controller aspects of your project, and what you come up with for that. I'm glad that you already have experience with this kind of thing, and your experience with designing and implementing a custom controller has long been a weak point for other projects on this forum (especially mine). When you get to that part of the project, please give us all the details of how you are going about designing your microprocessor for your system. This particular design process really needs to be “opened up” and made to be public knowledge. It would be widely beneficial to us all.
Good luck on your project,
-AC_Hacker