11,000 BTU DX GEO Heating

[MEMPHIS91]

The settling of the liquid at the bottom of the pond loop is what I was thinking was happening. I might add a larger accumulator.
Thanks for the chart, the tables I was looking at must have been wrong. I think I might be able to source methane through my local nexair company. Not sure the price yet though. Do you think it will improve the heat much? I'm willing to spend the money to make the system work better, but not if it's not going to be a lot better.
Thralls

[jeff5may]

It's a half ton compressor. At r410 pressure range, you will get this out of it. Down in the r22 range, maybe 2/3 of that or so. This is your window. Capacity and efficiency depend in how you tweak the system. Since it is a ground source device, performance will not change much from season to season like an air source unit does.

If you run propane/propylene, this unit should put out around 1kw of heat using 300 or less watts. With 410, you might get over 1500 watts of heat transfer, but at higher power draw. Either way, the thing isn't going to heat your whole home. It may or may not heat the whole greenhouse. however, it will keep the place from freezing and keep the fish alive.

[MEMPHIS91]

Awesome. Well I'll see what happens with the propene then. I could always add a second stage compressor. I'm pretty sure the DX coil can handle more.
I'd be happy with 60-65F temp in the greenhouse. It's pretty air tight and holds great well. It's got a black floor so the sun hearts it up quick. And one side is attached to my house.

[MEMPHIS91]

http://www.icarhma.org/APP_CONTENT/i...inal-03-04.pdf

Very interesting article. Maybe I can blend R290 and R410a and not have to change my oil?

This is a quote from the same article, "Expansion Device: A single hand adjusted needle
valve was used as the expansion device between the condenser and evaporator in the system in order to maintain an equal evaporator superheating for all three refrigerants."

Could I use a needle valve before my cap tubes? I would just make my cap tubes larger than needed. Having it adjustable would be amazing.

[MEMPHIS91]

UPDATE!!!
So I tired the cheap ($5) 1/4" needle valve rated at 400psi. AND IT WORKS! For now anyway. I have a 3,000 psi valve ordered (http://www.homedepot.com/p/Palmer-In...-FFB/205792622) just in case it breaks during the cold cold winter.
I could only find compression fittings so I just brazed it. LOVING THIS NEW TORCH!

I got it installed and made my cap tubes slightly larger than needed. I don't think only using this as a metering device would work. I think it would make it too cold. Using the cap tubes after works well because most the extreme cold is 6-12 inches for the valve.

I filled it up with R1270 in a warm water bath, this is a must for anyone using these type cylinders including R290. I got less oil and much higher pressures to work with.

I also install a meter that monitors volts, amps, watts and records Kwh.


I'm still fine tuning the system but as of right now I am 225 psi discharge, 65 psi suction. 155F discharge and 70F suction. I can fine tune the pressure with the needle valve now. It was 50F out side, it took the temp in the greenhouse from 60F to 67F in 10 minutes. And that was while I was still filling the system.
I haven't got a chance to play with it today its been to warm.
Shalom

[MEMPHIS91]

So after doing some serious thinking and calculating, I believe I can get a better COP with a larger compressor. So I just so happened to have a 10,500 BTU R22 55LRA compressor.
I knew that the small amount of liquid coming back to the compress on start up was going to soon kill the other compressor anyway so I pick up an accumulator in town. They don't sell a lot of these so I was able to talk them down some.
And what better time than to install the new needle valve? I also shorted the cap tube accordingly.

All I need now is two 1/4" flare nuts and I will have it all back together.

[jeff5may]

Nice. So much for the half-ton capacity limit. Your new configuration should serve as an awesome test bed. I predict you will learn a whole lot about what happens when you twist that valve one way or the other. Prepare to spend hours watching in wonder as the machine changes for better or worse. Just try your best not to overcharge the refrigerant loop.

[MEMPHIS91]

Yeah who needs limits Lol
I'm sure I will spend hours tuning on it. Just hope it's putting out heat while I am.
Not overcharging the loop was the main reason for the cap tubes as well as the valve, it gives me a safe range while not letting me push it to far.
I knew I should have bought extra flare nuts...... Oh well I'll wait till tomorrow to finish.

[MEMPHIS91]

I got everything finished and leak tested, I am giving it a good vacuum today and will start filling tonight.

This is a reply by sphere478 of the xtremesystems.or site I mentioned. Here is what he said after reading the thread.

---"""i've tried using needle valves as metering devices and do not recommend them cause they are too touchy they yes can work but you find yourself going back and forth between adding/removing refrigerant and adjusting the valve before you give up and kick it lol not really but they aren't as precise as a proper restriction like a cap tube, txv or fixed orifice

have you considered converting your ground loop to a water circuit (antifreeze/water) and using a heat exchanger and water pump? i actually have future plans of building a similar system and using a water loop instead of a refrigerant loop

if the system is sized and built properly and the refrigerant is fully charged and not overcharged the r290 should work great for pulling heat out of the ground i personally have found that 1270 performs better than 290 in the same system as a bonus though.

if you want to use r410 be prepared for the system to create a bunch more heat. compressor, discharge temps, and pressures will be higher and this effects the system. but may work out okay for your uses and i would like to hear you have done this if only for flammability reasons.
i believe a mixture of 5% r1270 95% r410 by weight (non scientifically but as a guess) would be about the highest ratio you could run and still not hold a pilot flame should a leak occur i do not know if that would be enough 1270 for your oiling concerns but would suspect it would be, as ratios of hydrocarbons added for oil return is usually low like that in other blends

i am reading the updates in your thread now and i am loving the project. high five. i'd definitely ditch the needle valve. you might use two of them though to make switching out cap tubes easier. dont forget about heat ex changers idono if you have been using them but if the condenser out line (liquid supply) like is soldered to the suction return (vapour) for a good length it increases the efficiency of the system

in the future you can make your own accumulators real easy if money is an issue. large copper pipe from the hardware store to create a space for liquid to get hung up before making it to the compressor. heat exchangers also help with this

oh and methane i don't think will condense in your system. it is very high pressure also. best avoided unless you are doing cascade. same with ethylene and ethane
another hydrocarbon not to try is acetylene. according to the p/t chart it might work and condense under perfect circumstances but it is reported to explode when exposed to oil on a few sites i've read. i would love confirmation on this though cause if that isn't true i'd love to try it lol

btw you did check to be sure that mapp was propylene? and not the other stuff?

how much gas did the system take? i bet it took a lot with a 300' condensing loop lol

if you are new to charging systems i advise you to pay more attention to how the system is responding and give it a long time to settle out before changing the charge rather than paying attention to the pressure it's self. a common rookie mistake is to charge solely on what you think the pressure should be. your system (&needle valve) will determine the correct pressure more than you will lol

i am typing this as i read your thread lol if you want to heat something then you might start with the r410 lol 404 is another good one (similar to 407c and 22) i fear though a lot of that heat is motor heat though haha. your amp draw will be higher.

btw what oil did you use? i must have missed that in my read oh wait nvm you now have a different compressor

glad to see the 1270 is working out for you in your other thread it is great stuff but dangerous """---

Here is the link to the thread on the site. Not your typical system

[jeff5may]

I have a whole tool box full of hardware and spare parts for hacking refrigeration units. I started out with a tackle box, but it quickly overflowed. I still use it for the small parts that tend to grow legs and wings. Valve cores, copper and brass fittings, orings, sanding tape, blade and spade terminals, etc. The little tools stay in there too. The box has the bigger stuff in it: valves, cutters, benders, flare tools, gauge set, hoses, thermometers, short sections of plumbing, etc.

These two boxes go with me every time I work on phase change systems. If I am short on materials or tools, they get added to the collection. I have found it is better to build a separate set of tools and supplies than to waste lots of time searching for a few specific things over and over. This approach has saved me way more time than the collection of individual parts is worth. Plus, things like flare nuts and access fittings are cheaper by the dozen.

I guess it just depends on how much your time is worth. I have a hard time finding enough daylight to do everything I have planned, so every minute I can save is a blessing. The more time I spend actually doing work instead of hunting for things, the better. The mentality of others regarding how much this or that costs, or whether or not I will ever use the same thing more than once in my life has been dispelled long ago. Chances are that sometime in the future, I will need more of what is in the box again.

I am not a fan of improvisational solutions in this realm. There are many things that you have to use to get to point B, nothing else will do the trick. You can try to kludge some of what you have available together, but the risk of failure is high. if I could hadda one of these, is not something I have fun dealing with, especially out in the field in the late afternoon. These sticky situations can really eat your lunch and derail or end your day.