DX Geothermal Pond 4 ton Heat Pump

[mejunkhound]

1 phase 220v to 3 phase 575v?

First thought would be external autotransformer to boost voltage, external bridge rectifier and feed the VFD with dc, and add in a big inductor (1 mh or bigger) in the dc line with a big as you have external dc cap. Feed the 575 V input vfd with whatever volts it asks for with your dc rectified voltage approx. the peak of the vfd input needed, which means your external transformer rms output about 1.1 times the vfd 3 phase input specified.

While you are at it, add a control system so your compressor is variable speed, feedback to the vfd frequency control pin via PID temp controller, comp runs continuously.

[MEMPHIS91]

Mejunkhound you just spoke in a language that I don't know. I will Google ask those fancy things. Would it be easier and cheapest just to buy a 220v 3phase comp?

[mejunkhound]

easier and cheapest just to buy a 220v 3phase comp

If you do not have a few old transformers, diodes, inductors and capacitors sitting on your parts shelves,

YES.

However, you need to be sure your VFD is able to supply the load with single phase input. The PFC (Power Factor Correction) boost circuit in some are able to drive the output from single phase inputs, some are not (depends on if the internal inductor is big enough). Google 'PFC boost circuits' for more 'learning experiences".

Look for 'PID temperature controller' on ebay to see what that is all about.

[MEMPHIS91]

mejunkhound, sadly I only have small electronic parts.

This model here says it will accept single phase, but a forum I have been reading only says it will cut the power rating by 50% so should I get one double this size?

I will for sure find a 220V 3 phase then. I looked at ebay for the PID temp controller and they look pretty simple, I was hoping to take control of this with an arudio or teensey. I would like it to take multiple system/house readings to make the system run as efficiently as possible.

Thanks for your advise and help

[jeff5may]

Do you really want a 3 phase variable speed compressor? The pots you linked to are cheaper because they are oddballs. Matching a vfd drive to the compressor and running off single phase 240 is a project in and of itself. You may end up spending more on the pot and the drive than the price of a single phase pot that will plug and play once you add a starting capacitor.

Any transformer that will step up 240 volts at 60 hertz line frequency and source 4 kw or so is going to be a large boat anchor. Even an inverter is going to be larger than a briefcase. The voltage that comes out of this power source needs to be connected with wires that have insulation that will not break down and let out the lightning. As you can probably imagine, the more reliable this power source is built, the higher the investment, both monetary and man-hours.

[MEMPHIS91]

Jeff, yes I have thought long a hard about the difficultly. And like most by projects they can take sudden turns and complete stops to research and fully understand an idea that may or may not work.
You can blame 100% of this idea on randen, he has it 3 phase already in his shop but has proven that one of these oddball pots can make for an awesome build. I believe that the vfd that I have posted is within a good price range and capable of doing what I asking. 4KW 5HP 10A 220VAC Single Phase Variable Frequency Drive Inverter VSD VFD | eBay
You are very right and wise about the needed wiring and extra upfront cost is one main concern. I really want to pave the way for people looking for a variable speed set up to have a proven way of doing it. Total cost is looking at less than 2 grand. If I can stay in that price range I will do what it takes (man hours/research) needed to make this happen.
It will take considerable time and help from y'all as well, but I will always repay in pictures and reports of success/failure.

Just found a danfrost for about $500 http://www.ebay.com/itm/DANFOSS-HRM0...8AAOSwf-VWWImJ
These compressors look about the same price as a 1 phase

[jeff5may]

Deal of the week:
Surplus City Liquidators

Half of retail price at only $302.00

Specs:
Evap @ 45/65 degF, cond @ 130/115 degF: 41900 btu/hr @ 10.9 EER
Evap @ 45/65 degF, cond @ 100/ 85 degF: 54700 btu/hr @ 17.6 EER

The ZR series copeland compressors are made for R-134a and R-407c applications. They usually come filled with POE oil. They are made as a universal, industrial replacement to retrofit an r-12 or r-22 system that has a burnt out compressor. However, they will work with r-22 running through them.

Product literature:
http://www.emersonclimate.com/europe...oll_FULL_0.pdf

Model breakdown:
Z - scroll
R - Air conditioning
47 - capacity
K - Kbtu
C - revision #
(blank) - mineral oil
T - three phase
F - internal overload
E - 575 VAC, 60 Hz power source
306 - BOM number

[MEMPHIS91]

Jeff, So are you saying the the savings of 3 phase and variable speed are not worth the extra expense?
That compressor is under rated for my system. Unless you believe 3.5 tons would be enough.
I have a 4 ton copeland scroll on my unit right now, so if I went with single phase I would just stay with it.
Yeah the 575 volt is kinda out of the question as the need parts would be crazy expensive.
The house doesn't ever need a full 4 tons, when temps are right the unit will run for a couple minutes and then shut off. That is why variable speed was my first choice. A full 4 tons would only be needed on the coldest of nights/high summer temps.
I guess I could buy 2 2 ton compressors? But if randen has already proven success why would I not go with the 3 phase? The vfd would also take control on the water pump as well, so I would be saving some on a controller for it.

[randen]

Memphis

If I may humbly suggest. Keep it simple. Stay with single phase. As your system may not excel in other areas of efficiency and too small to start to realize the benefits of 3 phase control. Powering a 3 phase compressor would require a larger VFD to operate on single phase.

I'm actually driving a 6hp compressor de-rated to about 5ton. I also have 3 phase 575v and 240v available.

Randen

[jeff5may]

Look at the specs.

The r22 unit I cited is rated for 3.5 tons at a wide temperature split. At a narrow split, it does around 4.5 tons with less power draw. 3850 watts at wide split, 3100 watts at narrow split. It's an old school twin cylinder recip compressor. The beast weighs 76 pounds.

The ZR47 pot that you cited is rated at the same two splits in temperature. At the wide split, it is rated for 39400 btu, just over 3 tons. At the narrow split, it is rated for 4630 btu, just under 4 tons. Power draw is 3430W wide /2340W narrow. It weighs (only) 62 pounds.

If everything else in the system acts perfect, you stand to gain 10% in efficiency while losing half a ton of capacity with the oddball compressor. Yes, slowing it down with a VFD will give you even more efficiency. In that case, look up a "twin single" recip pot. It will slow way down to 2 tons.

I'm not trying to tell you what to do at all. I was just pointing at a good deal on a pot that will plug and play with that turbotec heat exchanger.