AC Style Heat Pump Build
 

Thanks AC! Must have read "The Great Thread" front to back three times now.

Aiming for a Randen type setup at the end. There is a 6 ton Copeland 3 phase in my shop that just needs a VFD....a nice PowerFlex would go good with the PLC 5/11 currently running my house.

I spend the last couple years building a house. Solo budget build--not a mansion. Read a book and figured I'd give it a shot. Much like the way you guys build your heat pumps!

Now that we live in this mostly finished house and winter has arrived, the 6kw hot water tank that's presently pumping host water through our floors will not cut it. Admittedly I had some bad air leaks around half installed doors, but after I saw our last hydro bill--holy F.

I picked up a free 3 ton R22 1PH commercial air conditioner with a coaxial condenser. Perfect way to get started using this machine as a ASHP. Just waiting for my eBay tools to arrive.. silver solder, evac pump, gauge set.

Along with the tools are the upgrade parts. Maybe a smarter man would get started on this unit as-is, but according to "The Great Thread" that cap tube needs to go. I've got TXVs coming. Reversing valve, sight glass, filter.. all the goodies.

Naturally she'll run on R290 like any good hacker machine. We're going to start as an air source unit. I do have a backhoe, but my lot is small. Interestingly, the land is swampy black muck that's always 100% saturated in water. May investigate ground source options later.

I've got lots of forums posts to read until my parts show up!

Thanks again all you guys that posted your projects. I'm just copying your hard work.

Welcome to the forums! It sounds like you have a plan and some gumption. I can't wait to see what you come up with.

Sounds like a great project! Keep us informed on your progress, I always love a good DIY solution.

My donor machine was free, but had no history. For all I knew, it was a total burnout.

I evacuated the system and let it sit for a week. No micron gauge, but no discernible loss in pressure either. If it leaks, it's slow.

Also jogged the compressor for the first time. Hermetic 3 ton Tecumseh reciprocating. Ohm metered before I ran it for the first time, and that looked good.

Still waiting for parts. TXVs and distributors should be here any day now.

Figured I'd get started by chopping out the old cap tube. Pressure tested with compressed air. Pressure dropped a few pounds. I was unsure if it was because of temperature differences, or a leak, so I threw it in the tub.

My new joints are tight, but there is a very small 1 bubble/min pinhole from evaporator itself. Good enough to get started. If it looses gas at an annoying rate, I know where to find it.

Picture of the donor unit. Crappy homemade SAE hose and tire gauge can been seen. Was desperate to play before my manifold set came.

How great is that... 3T single phase compressor and a coaxial condenser ready go. The wiring is a mess, but it all works.

A smart man would have just dragged the whole machine outside, gassed her up and start making heat. But I couldn't ignore Vlad's position on eBay TXVs.

Why bother with a cap tube when you can have a perfectly sized TXV for a reasonable price? The Sporlan literature is nicely laid out.

Considering I'll be on 290, I'm going to run the machine as an outdoor unit. All the controls, relays and contractors are going inside. No source of arc if I get a leak. The PLC will be doing all the smart work anyway.

Parts arrived, machine chopped up and put back together. Gas'd 'er up last night, and I've got frosty goodness. Next step, drag the beast outside and get it plumbed into my hydronic system and controlled by the PLC.

You know what's been a challenge? Living out in the sticks, and getting ACR fittings. The hardware store has ACR sized soft copper, but that's it. I can't find a fair priced online retailer for ACR fittings that will ship to Canada.

Swedge punches have been useful to make coupling. Having all sizes of ACR pipe on hand from 1/4 to 3/4 is also useful as you can telescope them to change sizes.

I've been using Stay Brite 8 for soldering, because you can do it with a little MAP torch and you don't need to run nitrogen. On the other hand, it requires tight fit up. Brazing with Silfos would be better here I think.

In the picture, all the fittings were rare dusty finds at the hardware store--not normally stocked. Found some 1/4 90s--nice!

Wow! Great going.

I would have kept things simple and used the old cap tube, etc.

But fools rush in and really make things happen!!

Good for you.

You are in Canada??

Gets pretty cold in the winter I hear. You might want to consider Ground Source, but not til things warm up. Ground source is what really increases your COP.

Awesome gumption.

Best,

-AC

I was going to install a high efficiency gas boiler until a friend of mine showed me your work. You guys have done the hard part! Makes it easy to jump right in.

Yes, it's been a thought. I'm coastal, so not much variation in the seasons.

Water main is supplying 42*F right now. Last week the air was warmer, and this week its colder.

For my climate, being able to select between air or water would be the best.

I think final evolution will be both an air source evaporator and a ground source evaporator (likely water main). Put both on a common suction header. Each gets their own TXV and a solenoid valve on the liquid feed.

My neighbour moved away earlier this year. Left his house for a boat. He was also a collector of fine treasures like myself. He left me all sorts of interesting things while he was cleaning out his house. Really great guy, sad to see him go.

I forgot I had this beast! I might be adding a ground source sooner than I thought.

He tells me it was from a soft serve ice cream machine. Kept it in his shop for a long time. It's heavy, and it's all stainless. It's a purpose built DX evaporator. I think there was an auger that used to sit inside this thing, and ice cream would come out the front?

I'd like to use it as an evaporator, and add ground source to my heat pump. But with municipal water, rather than a closed ground loop. I think brazed plate exchangers are great when you have two clean closed loops--can't beat that density. But for dirt municipal water, I need something I can take apart and clean.

I can have a machine shop weld a plate on the open end, and I can make a removable plate on the flanged end. I imagine it would perform better if I add some kind of spiral diverter to the inside. Force the water to take the long way and make good contact with the outer coil.

Looking for ideas! Being able to clean it is a must.

You will need a reversing valve and a control that can do defrost. Did you get them?