11,000 BTU DX GEO Heating

[MEMPHIS91]

Howdy again, as some of you know I have a few projects that are still in the design stage, mainly due to money issues and an unsure time frame of a off grid dream.
This build is not limited by either one. And will help give me real data for the 4 ton DX system if I do ever decide to go through with it.

The Plan:
My greenhouse is 24 feet by 16 feet, and is built onto the front of my house so only 42 feet of liner wall space, 7-8 feet high, is triple walled 8mm poly panels. Same for the roof. I heated it with wood last year but I hate having 2 fires going plus I would like to heat my fish tank water in the aquaponics system.
The Idea:
The 17 feet deep 2-3 acre pond is 75 feet from the greenhouse. I want to run a loop of 300 feet (total 150' to and 150' back) of 1/4 or 3/8 copper into the pond. 75 feet of which will be buried 6-7 feet deep all the way to the pond, then the rest will be sunk 6 inches from the bottom of the pond.
I have a spare 6,500btu rotary window unit that I will be harvesting the compressor and evap coil/fan from. Here is where it get tricky. I want to put in a 3 way valve setup on a thermostat that is in the fish tank. It will bypass the evap coil to a non copper coil (copper bad for the fishes) in the fish tank.
Parts Needed:
Compressor I already have
Evap and fan I already have.
Thermostat I already have
300 feet of either 1/4 inch or 3/8 copper tubbing. (ideas? I thinking 1/4 should be ok, but that is a lot of resistance for a 6,500 compressor.)
Oil separator, Jeff5may, you posted a picture of a small oil separator in the 4ton thread, I'm having the worse luck finding one small enough for half ton. Do you happen to know where that image came from? Or does anyone know where to find one? I know they are used on extreme computer chillers but have been unable to find where they get them, because most are not built in the states. I found this one Q E HVAC R Refrigeration Oil Separator 1 2" ODS New | eBay but I know its too big and will probably not cycle the oil back at the right time/volume for a small compressor.
3 way valve. I'm thinking this will be fine, Ranco V3 310081 7GD B1227308 3 Way 1 2 Ton Reversing Valve 10283 | eBay

I will start building just as soon as parts arrive, I'm tired of keeping two fires going in the winter.

Thanks guys!

[jeff5may]

You can use a bullet strainer as an oil separator. Supco no. SUD 115 is the common one. Two Tubes facing up, single tube facing down. Bottom tube feeds long, small diameter cap tube back to suction line.

[MEMPHIS91]

Jeff, Thanks I'm looking into that right now. I know I should have ordered more of those. I just used my last one. I can't seem to find this application of the SUD115 anywhere. Makes total sense though. Would 2 of them back to back be safer?

Shopping list.
Stainless steel coil for the aquaponics heat exchanger http://www.ebay.com/itm/304-304L-Sta...-/290552612112

45% Silver braze to braze the copper to the stainless http://www.ebay.com/itm/98102-Lucas-...item2357e81a0a

SUD 115 Modified drier/ Oil Separator http://www.ebay.com/itm/Copper-Liqui...item3f4eb94254

3 way valve http://www.ebay.com/itm/RANCO-V3-310...item3378ddafdf

I'm getting the 300 feet of 3/8 copper locally because its much cheaper that way. And I know what I'm getting.

[marx290]

Originally Posted by jeff5may

You can use a bullet strainer as an oil separator. Supco no. SUD 115 is the common one. Two Tubes facing up, single tube facing down. Bottom tube feeds long, small diameter cap tube back to suction line.

That is great! I wasn't sure if it would work. My best plan of attack for a oil return, was a sort of vortex separator on the discharge of the compressor, where oil would tend to fall to the bottom. A capillary tube would carry oil back to the compressor suction. I figure some sort of strainer would be advisable, in order to avoid plugging the capillary oil return line. I suspect that even a well designed system would compromise volumetric efficiency slightly, but would certainly be necessary for compressor health in some instances. Then again, keeping the heat exchanger walls cleared of oil, could improve thermal transfer too.

That's interesting. Thank you

[MEMPHIS91]

marx290, thanks for the links, the link was down, but I did find a google drive through that same site with a GOLD MINE of info.
https://drive.google.com/folderview?...DQ&usp=sharing

I am just now fully learning the P-H diagrams. I was always a try try try try til it fails then try try try again til it work kinda guy. But I am putting tons of research into this build. So I knew I needed to start with some basics of the math/science behind it all.

[MEMPHIS91]

Progress has been made!
So I started just loose fitting things. First the discharge on the compressor to the intake on the oil sep, not the best idea I know, see below. -1/2"-

And the discharge of the oil sep into the reversing valve -1/2"-
.
I knew the discharge from the compressor would have too much vibration to have a straight run to the oi sep, so I fixed it with a big loop.

The evap(now the condenser) had 2 cap tubes, so 2 intakes, I saved the cap tube and brazed some 1/4" onto them.

Then I ran the 1/2" from one side of the discharge of the reversing valve to the 2 1/4" intakes on the condenser.

The 2 1/4" tubes fit perfectly inside the 1/2". BEFORE

Brazed thoroughly. DURING

I was going to clean it up and take another picture, but I decided to move it into place first, and of course picked up the still super hot 1/2" line...... needless to say I am pecking with 2 fingers in between icing the burns in between typing...

Any way, next question, how much oil do I add and do I add it to the oil sep or the compressor? All to poe was drained. I have been looking for a while for the answer, still searching now.
Also I'm think 1/4" is to large for oil return. Would 1/8" be better?

[MEMPHIS91]

Howdy guys I got a lot more done thanks to the help of a GOOD friend.

First I swagged the 3/8" lines, its SO much easier than 1/4"


Then I laid out the line, brazed it all up, pulled a vaccum for several hours, made sure I had NO leaks, then zip tied about 20 bricks to the end that is going in the water.



Then the digging started, I got down to 9 feet deep in some places, but never less than 6 feet. When we got close to the pond the machine tried to slip and almost went for a swim, so I will have to dig about a 4 foot spot by hand.




I insulated 2 feet down as it came into the green house.

[jeff5may]

Here's a good article on oil separation:Oil management in a refrigeration system - Carly : the international expert in refrigeration components


If you use the service valve for your gas outlet, you can flare your stainless line and save some trouble.

[MEMPHIS91]

Jeff, again awesome info. Seriously if you are ever in Oxford, look me up. I owe you a beer, and solar cooked organic homemade meal.
Just added this to this list of parts needed BC49X11 Supco Capillary Cap Tube 049 ID x 11 ft Series for Refrigerators AC | eBay

Sadly I will have to come out of the oil separator to a 3 way valve THEN into the stainless steel coil. So its all brazing looks like, but the %45 silver should flow really nice.
I'll be posting a diagram soon.

UPDATE: Found this quote from a really good read, "Actually it's just a "strainer" with nothing more then a screen inside. And yes the basic idea is that the larger internal volume of the strainer as compared to the 3/16"od tubing feeding into it, will allow the velocity to decrease, thereby letting the heavier liquid drop away from the gas. Same principle of any phase separator, this one just happens to be rather small (and cheap).

Of course an even better phase separator has the refrigerant entering from the side, taking advantage of centrifugal force (not just gravity) to separate the liquid from the gas."

-http://www.xtremesystems.org/forums/showthread.php?144007-Morphing-Air-Conditioner-into-Autocascade-System

[jeff5may]

Originally Posted by MEMPHIS91

Jeff, again awesome info. Seriously if you are ever in Oxford, look me up. I owe you a beer, and solar cooked organic homemade meal.
Just added this to this list of parts needed BC49X11 Supco Capillary Cap Tube 049 ID x 11 ft Series for Refrigerators AC | eBay

Sadly I will have to come out of the oil separator to a 3 way valve THEN into the stainless steel coil. So its all brazing looks like, but the %45 silver should flow really nice.
I'll be posting a diagram soon.

UPDATE: Found this quote from a really good read, "Actually it's just a "strainer" with nothing more then a screen inside. And yes the basic idea is that the larger internal volume of the strainer as compared to the 3/16"od tubing feeding into it, will allow the velocity to decrease, thereby letting the heavier liquid drop away from the gas. Same principle of any phase separator, this one just happens to be rather small (and cheap).

Of course an even better phase separator has the refrigerant entering from the side, taking advantage of centrifugal force (not just gravity) to separate the liquid from the gas."

-http://www.xtremesystems.org/forums/showthread.php?144007-Morphing-Air-Conditioner-into-Autocascade-System

The two or three main posters in the cited thread are regulars on the xtreme forum. They do this refrigeration "alchemy" for a living, so they can be a great help to you and the rest of us. Unlike other forums, these people have no problem with giving a straight answer to the questions that we have difficulty with. Especially with respect to design parameters of an "unconventional" nature.Reading lots of threads over there, as well as asking the right questions of the individual experts, helped me immensely in understanding the theory behind how these rigs do what they do.