DX Geothermal Pond 4 ton Heat Pump

[MEMPHIS91]

Randen, can you provide a link to the $1,400 one you mentioned? Because after 30 minutes of looking I have come up empty. Yes that does look like a really good option, with some really good numbers. Plus it would give me a new indoor handle as well, which is really nice. But I just can't find it for that price.
I have already purchased the coaxial coil for this build, I'm looking at $1,000 to have the compressor and VFD. Then probably another $300-500 in sensors and txvs (if the ones I have now don't work). This unit will have a variable speed compressor to really make the numbers soar. That is assuming everything works the first time.
What will I have done if I buy a premade unit? Only cut out on my bills and allow me to heat when its really cold. I will always know there is more BTUs in the pond that I am just wasting. I will have no lead anyone to help build anything and for people like you that really is the only option. AND I will have a coaxial coil I need to sell. For around $1,500 I am willing to take a few risk to make a unit that will more than likely save me that much in a few years compared to the Climate master. I will know that I built it with my own hands and will be saving every penny I can. I will be sticking my finger to big government who says it can't/shouldn't be done and will inspire the next man to build his own. (like you have).
I can not do this on my own, I would have failed 1,000 times more on every build if it was for you guys and my local friends. IF this can be done, help me if you will. Because I my regret it later, but I will regret even more never trying. 6 months ago I didn't know how an AC system even worked, now I have 3 going on 4 builds under my belt and learning more everyday. And I'm ready to build this monster, I'm ready to hear that VFD ramp up the compressor and start pumping heat from 17 feet below the earth into my humble county home.
You and Jeff have both issued strong warning about this build, and you both are the one that I stand to gain the most help from. I have the money (well almost), I'm willing to listen BUT only if you guys are willing to help me make this unit, not go the easiest route.
As it stands I feel like my only 2 option (that I'm willing to try) are either a 2 stage compressor, or the 3 phase VFD controlled one.
Both we be better than a premade unit (not the $10,000 ones).
This has all just been what is on my heart. I know I'm young and probably really foolish in my choose but I really do believe this is what needs to be done.
Thoughts? Concerns? Complaints? Ideas?
Thanks again guys I respect every word ya'll say.

[MEMPHIS91]

Just found this bad boy! 4 New Danfoss Scroll Air Conditioner Compressor HRH051U2LP6 208 230 Volt 3 Ph | eBay

[randen]

Memphis

I encourage the DIY side when it makes sense. But as you can see, the cost of the parts are beginning to add up. Getting the parts to play together well can be a bit of a struggle as you have seen.

The build of a ground source or even an air source water heater is another story. The parts are cheap and sometimes free. The effort is low. The return on investment is beyond huge. So I would support this all day.

Now, I'm not going to leave you high and dry because I think the value in the DIYing this heat-pump doesn't make financial sense. I've made you aware and the rest is up to you.

Again with the VFD driving a 3ph compressor with 1ph power maybe a little trouble. I had tried driving a 3ph motor with a VFD and one brand of drive worked and the other faulted out. But that was a number of years ago so I can't offer any empirical knowledge.

Oh yes the link.Climate Master Tranquility 20 Geothermal Heat Pump | eBay

Now the ad wasn't specific to the power requirement. It says 3ph. but that could be 460volt and that's no good to you. I've seen other HPs 1ph and less money. As I had mentioned its high season for procuring a heat-pump now.

What about seeing if you can get a scrap outside unit around 2- 3 ton 240v 1ph even if its a recip. I was able to keep a large not so air-tight shop fairly comfortable with it. 1600 square feet. With better HXs I bet it would have done a lot better. For the weeks where the temp dropped to -20 Deg. plus huge wind it wouldn't keep the shop comfortable.

Randen

[MEMPHIS91]

Randen, I am confused as to what changed your mind, when this was DX you even offered to look at a VFD yourself to see if it would allow 1phase input.
Trying to find a climate master anywhere close would be a miracle, they just are not done around here, shipping or driving to get it would be expensive as well. I just don't understand your strong opposition? You would rather see me buy a used system that may or may not work, and for sure will not be sized to match my indoor coil than to do it diy? Or are you just against the 3phase? I haven't heard enough bad things about the 3 phase to consider wasting so much energy. As my last link showed, if I'm patient I can find a NEW 3phase pretty cheap.
Are you saying I should hack a air source and turn it into Geo? Or saying I should just go air source all the way? Because I have a 4 ton air source right now.
Please provide more facts as to WHY this is such a bad idea, have you looked into the info on single to 3 phase with a vfd? People are doing it all over the place with great success. I do understand you had a compressor mess up but without more info I have no idea how to use that piece of info.
I should probably start another thread when this build gets started so someone does not have to wade through all this debating in order to learn something about the thread title.
You of course have every right to hold back your experience and knowledge from me, but I assure you, you do not leave me high and dry.

[randen]

Memphis

Don't shoot the messenger. I'm only sending you the facts. These are things I know because I have done them. I'm not sending you something I've only read about.

My first attempt was with scrap and made a 3 ton heat-pump and it worked reasonably well and cost nothing but my time. As you had found in your area they are scarce to buy. For me a 3.5 ton Climatemaster was $7000.00 to purchase. So building one made some sense.

VFDs well yes they can work well. HERES what I know: I purchased a VFD for I think $250.00 (Chinese) I checked and you can purchase one for about $160.00 5hp or 4kw. This I had tried on single phase and it had faulted out but 3 phase worked fine. Seems they cannot tolerate an unbalanced leg.

Today while I was working I remove one leg on my VFD powering my unit with single phase and it operated fine. Now this is a high quality made in America Allen Bradley Powerflex 70 7.5hp VFD. I believe I paid $400.00 for it. A 3 phase contactor with overloads and a low voltage power supply would cost me more. That is part of the reason I went with it. The other is starting a 6 HP electric motor does draw some current.

Looking On line I found this:

Allen Bradley 3HP 20A B 9P6 A 3 AYYANC1 Series A PowerFlex70 AC Drive $799.00

I KNOW IT WORKS single phase.

You may be able to find one cheaper I don't know. BUT make sure you size it correctly. If, like you have found, experienced a locked up a compressor and your VFD is oversized it will not cut the current and you will have a fire.

Now that VFD that will operate single phase may set you back $500.00 plus will never save you enough in electrical costs no matter how long you live driving a 3 ton compressor.

Things I Know: Yes you can build one from scrap and it will work OK. You can spend more money and time and DEVELOP one with better performance. You will take a little performance hit with propane. (R290) from the compressors rating. Larger brazed plates (for ground loops)HXs are better. You must protect the evaporator from freezing. You must install Current/High/low pressure protection. Good flow rates are also most imperative.

Its DIY. Do what you wish. Show us your results.

But I would not recommend building your own boat if you could pay a fare of a few bucks to cross the river on a ferry.

Randen

[MEMPHIS91]

Randen, I'm not shooting you, I feel like the one being shoot here.

I know you have had hands on experience with vfds, and I have only read about them, but I have read where others have used them with tons of success. The rectifying bridge is only rated at a certain number of amps on the incoming side of the vfd, the single phase pulls about double the amps and therefore overloads the bridge. You must derate a vfd by doubling the size, (5hp to 10hp). And that is what I have done. Did you read the entire thread or just chime in on the last few post, because I discussed/linked all this already. The vfd is $300, and I just got dang lucky and got a 51k btu 3 phase compressor for $300. So total price is $600. That is an awesome deal.

Yep fire is very much so a danger. That is why safety sensors are a must. Though if the single phase has a breaker and the vfd starts pulling more amps, then the breaker should trip before something goes boom.

So you are saying that single stage vs variable speed will never save me $500 in my life time? That I just don't see. I will need less than half the rated size most of the year. It will take no time at all to save $500, plus easier on the compressor as Jeff's article said so I'm also saving on compressor replacement cost.

Why am I going to take a performance hit with R290? I have 410a available if need be.

I already bought the coaxial coil from buffalobillpatrick, and it will have all the needed sensors as well.

Again your analogy really doesn't do this project justice. I have NO ferry, you just said your self that now is not the time to buy and that the ferry units are hard to find around here. So I should blow another $500 bucks on firewood this year in order to save on a factory ferry unit that will be just about as hacked as the project I'm building? That doesn't make sense to me.

Your opinion DOES matter, I just am stating what I believe to be fact based on well documented work.
Shalom

[jeff5may]

I've been off the forums for a few days, just checked in and saw this. Wow, what a turnaround! Last week, Jake was ready to pull the trigger on a compressor of some sort. This week, it's consideration time: price vs performance vs warranty vs everything.

I can relate to the concern about the unknown. I can relate to the concern of buying new vs roll your own vs buying used. It's a good thing that he took a step back if he is unsure of his abilities, because (as Randy stated) this a big beast to slay. Totally different animal than something that will run off 120 Volts. When things go wrong, you may be bursting or torching a $500 component. This could happen more than once.

Nothing is without risk (as with buying a new car, house, etc.) but at least if you buy a new unit and have it commissioned by a certified Joe, you have a support network to fall back on. Once you enter the realm of used or pieced together systems, that support net is pretty much nonexistent. Noone will want to touch it if something goes wrong. Forget about the insurance company covering any damages.

However, to purchase a unit that will perform at the level that can be achieved by doing good research, careful selection, and some trial and error will certainly cost several times more than the raw materials. That five year warranty pretty much doubles the price alone. Any sophistication or added functionality adds up exponentially to the base price. When something goes wrong, especially with a ground source unit, the caliber of techs who know what to do with it charge much more for their time as well. The energy savings may or may not catch up to the increase in upfront investment for a decade.

So, for a $2000 rig that you call your own, you may end up paying 5 or 6 grand for an equivalent manufactured and installed unit. Now is the best time to decide what your peace of mind is worth.

[jeff5may]

OK, so Jake was writing a response the same time as I was last night. My bad, I should have refreshed the page. I went to bed instead.

What Randy said is what you already know. Using propane with a R410a pot will yield you less BTU output than its rated value, due to the reduced head pressure. With even-steven COP, expect around 3.5 tons of capacity on a bad day. Since this is a commercial-grade compressor, it will most likely beat its rated output (and corresponding derated output) in the water-source configuration. Just don't expect 5 tons of capacity at 200 - 250 psig of head pressure.

I would definitely heed his words about your power source. If you set the inverter up correctly, it will not start a fire by burning up your compressor, itself, or your power line. The VFD's have oodles and oodles of settings to set parameters, conditions, and boundaries for pretty much every aspect of their operation. I cited a bulletin from Copeland/Emerson that defined a few of the VERY important parameters for an industry-standard drive, and Randy has first-hand experience in the road you are following. I imagine you will become intimate with your particular brand of drive (and its quirks) along the way.

With the rig you have planned out, I don't believe you will have the oil control issues that the greenhouse setup is showing. Since you are using a comparatively smaller HX on the outdoor side, the oil will not need to be separated, it can flow straight through with the refrigerant. Also, with R290, it dissolves better in the refrigerant and will find its way back through the pot with ease, even at reduced RPMs.

Regarding the greenhouse setup, even with (somewhat) reduced oil flow, the original pot did not die of oil starvation. This happens like the Mobil 1 commercials on car engines. If the pot doesn't get much oil, it starts letting you know before it fails. When valves and bearings get hot from increased friction, they get pretty darn loud compared to normal operation. If your original pot experienced these conditions, you would have noticed some uglys during the autopsy. It looked nice and shiny on the inside, but nevertheless it is better to err on the safe side.

[MEMPHIS91]

Jeff, you are right, this is a totally different machine than I am use to building. And I do understand that I may loose some expensive parts along the way. But as you have pointed out it is still much cheaper to build my own. I need no peace of mind, any system can break down at anytime, it gives me more peace of mind knowing I built it and can fix it when it breaks. Not wait of another company or worse yet have a used unit that I would have no idea how was set up.
AH gotcha, I thought Randen meant I would loose efficiency, but he and you are saying I would loose capacity of the compressor, yes I was counting on the because I don't need 51K BTU. And your right it should not have any oil return problems, even at lower speeds.
I never did burn up a compressor, I got hasty and cut into it. Though I could tell it wasn't getting the oil it needed. I fixed that though. Good to know things get noisy before they break. I'll remember that one for sure.
Oh yes VFDs are starting to become my very close friend. I am listening to all advise given and trying to make it all work. I already have the manual for the VFD I plan to buy, I read it as I get time. Things will be set up to keep it from going boom boom.
Thanks for the reply Jeff, I am now saving up for the VFD.

[MEMPHIS91]

Just now starting to look into electric expansion valves,
New Carel Electronic Expansion Valve E2V24BWAE0 3 8" 3 8" ODF | eBay

Pretty sure the price is right, but what the heck controls them?
Is it worth it?
http://www.achrnews.com/articles/823...-valve-control

Also should I start looking for a variable speed indoor fan? Or is the fixed speed I have now ok?