The Homemade Heat Pump Manifesto

[AC_Hacker]

Wow, awesome brazing there Vlad!

What is that tool that prevents loss of refrigerant called?

Also, in this photo:

It looks like this is a water-refrigerant HX, right?

It would be useful if you could give us a bit of information on this. It appears to me that it has water running inside of the refrigerant pipe, correct? It would be useful to know what the rated capacity was (I assume about 1-Ton) and what the outside diameter is of the tubing used, what size is the approximate size of the HX assembly, and about how many turns were used in the HX.

I suspect that some of our readers might want to try to make something like that.

I'm also a bit surprised that there isn't more insulation around it.

Best,

-AC

[Vlad]

Originally Posted by AC_Hacker

Wow, awesome brazing there Vlad!

What is that tool that prevents loss of refrigerant called?

Also, in this photo:

It looks like this is a water-refrigerant HX, right?

It would be useful if you could give us a bit of information on this. It appears to me that it has water running inside of the refrigerant pipe, correct? It would be useful to know what the rated capacity was (I assume about 1-Ton) and what the outside diameter is of the tubing used, what size is the approximate size of the HX assembly, and about how many turns were used in the HX.

I suspect that some of our readers might want to try to make something like that.

I'm also a bit surprised that there isn't more insulation around it.

Best,

-AC

Yes, you are right this is tube in tube HX made by Packless
Heat Transfer Coils Manufacturer | Condenser Coils | Heat Pump Coils | Chiller - Evaporator Coil | Air Conditioning (AC), Heating, Refridgeration Parts

As soon as weather cool down a bit I will open HP and take more inside pictures and post more specs.

This type of HX is very common on office type (usually installed above ceiling tiles in offices) AC/HP. They are very compact and have good capacity.

They are called: "coaxial heat exchanger". The inside copper tube has special shape that makes it so efficient. They are not cheap when new but you can find used at any metal recycle depot @ 10-30$. Recyclers don't like them because there is very little copper and it is buried under steel shell.

[Vlad]

Very useful pdf about refrigeration gauges. A must read material for DIY and I bet many "professionals" have no idea how to connect and disconnect gauges with minimal refrigerant loss and without adding non condensables in your system:

http://www.pearsonhighered.com/sampl...0132223678.pdf

[Vlad]

Originally Posted by AC_Hacker

Wow, awesome brazing there Vlad!

What is that tool that prevents loss of refrigerant called?

-AC

Just Google: thumbscrew core depressor

[BradC]

Originally Posted by AC_Hacker

Here's the link to the awesome chart...

The chart is huge... download & save for future reference.

I have a copy of the original Excel spreadsheet that pdf came from if anyone wants it.

Been a bit quiet lately. We've actually had (having) a wet winter this year, which while very very welcome, has somewhat hampered my hvac tinkering (all my stuff is either outdoors or in the roof and requiring tile removal). Roll on summer.

[AC_Hacker]

Originally Posted by BradC

I have a copy of the original Excel spreadsheet that pdf came from if anyone wants it.

Sure, please post the spreadsheet. The forum software is a bit picky about file size. You should try it as an xls, but if it's too big, zipping it might make it small enough... If that doesn't do it, you might have to resort to an external download service. Personally, I find some of the restricted attachment size limits to be too severe. I have wanted to post lots of PDFs and also spreadsheets in the past but was unable to do so.

Originally Posted by BradC

Been a bit quiet lately...

Yes it has, I've gotten caught up in removing a large tree that had grown up between three small building structures, none of which I wanted to damage. It is going well, but it is not the kind of project I was looking forward to this summer.

I'm still interested in doing the refrig tool thread, so keep that one on the back burner.

And I'm sure that at least several of us are anticipating the results of your work with that gargantuan brazed plate heat exchanger you illustrated with your photos previously. That should be really interesting.

By the way, in case you didn't see it, Vlad has successfully converted an R22 water-to-air air conditioner to R290 and it is in use cooling his house. He also use some interesting techniques to upgrade bar-b-que gas for use as a refrigerant... his process should be familiar to you. Now, I believe that he is intending to put a non-refrigerated, ground loop cooled air handler ahead of his heat pump in an attempt to boost the performance with a low energy burden. That's another project I have my eye on.

Originally Posted by BradC

We've actually had (having) a wet winter this year, which while very very welcome, has somewhat hampered my hvac tinkering (all my stuff is either outdoors or in the roof and requiring tile removal)...

I bet that all of Australia has been quite thankful for the wet winter. As I recall, it's been pretty dry down your way for a while now...

Best,

-AC_Hacker

[kbonk]

Hi Vlad,
have you considered add a HRV in front of your unit?

[Vlad]

Originally Posted by kbonk

Hi Vlad,
have you considered add a HRV in front of your unit?

I was thinking about it but I don't see myself paying 600-700$ for ventilator and core. Pay off will be like 20 years. I have vent room which is 9x9 small room located on 3 floor. All my ducts go there also I have 8" opening for exhaust and 8" opening for fresh air and I want to use this room as a plenum.

This summer I am very lucky because we have probably record high 91F+. This is a real test for my DIY AC. My AC is only 12000btu and it is not enough for 3000sqft home. I tried large coil (got it for free) for precooling outside air. I just circulate water in this coil. It all works together very well. The temperature is very comfortable. All this set up only takes 3A@240V for AC and 5A@120V for fan unit(I will get rid of this fans but weather is too hot right now for playing with this unit I just don't want to be executed by my wife).

So, (3x240+5x120)x0.08/1000x12x30=38$ It is not bad 38$ for cooling 3000sqft home. If I add a HRV the bill will be ?? 35$

[kbonk]

understood, I reclaimed a HRV on from a job site the heat exchanger are made from Coroplast - Manufacturer of Corrugated Plastic Sheets should be very ez to make, if so inclined

[AC_Hacker]

Originally Posted by kbonk

understood, I reclaimed a HRV on from a job site the heat exchanger are made from Coroplast - Manufacturer of Corrugated Plastic Sheets should be very ez to make, if so inclined

There have been both useful discussion and experiments on this very idea right HERE.

-AC