Air Source Heat Pump (ASHP) Hacks & Mods

[AC_Hacker]

Originally Posted by Acuario

Let me know if you want any more photos/details and I'll post them.l

Yeah,

I'd like to know more detail on how you went about using the TXV, that's one of the big hurdles in converting an air conditioner into a heat source.

Also, does the unit you're using have a single speed compressor? Single speed fan?

If it is multi-speed, did you have to do any mods to make it work for you?

I'd like to see some details on the radiators that you are using.

The usual radiators that are available in the US assume pretty high feed temperatures, like 160F to 180F.

-AC_Hacker

[sparkchaser]

Hmm... I have a couple window ac units in my shop, a 230vac 12,000btu, and a 115vac 8,000btu unit. I was thinking of experimenting with one of these as a heat pump, first by simply reversing it and putting an external thermostat on it, then perhaps turning it into a mini-split, putting a line set on it so it doesn't have to sit in the window, then start experimenting with GSHP. I saw a company in the Portland area advertising on craigslist which installs DX (direct exchange) systems using a horizontal boring machine. I think I can duplicate such a boring machine pretty easily- it looks like a hydraulically powered DeepRock water drill but designed to drill horizontally. I'll definitely be picking folks' brains, (especially ACHacker) so I won't have to reinvent the wheel so to speak! I have some training and experience in HVAC, though I definitely am not really at a professional level, so I stand a fair chance of success, though my main limiting factors are my wife and money for parts! She doesn't like me spending money of such frivolous things as energy conservation- she about flipped when I spent $2000 on R-50+ cellulose attic insulation last week! But I had to reasure her the value in it will be reflected in our electric bill.

[AC_Hacker]

Originally Posted by sparkchaser

I think I can duplicate such a boring machine pretty easily- it looks like a hydraulically powered DeepRock water drill but designed to drill horizontally. I'll definitely be picking folks' brains...

Learn everything you can about the soil formations in your neighborhood. The closer to your house, the more accurate the information will be.

Call well drillers, call GSHP drillers, call the state geologist.

Get in touch with another EcoRenovator who also lives in Washington, His forum name is Geo NR Gee, he's a real nice guy, I was up in Washington and met him, you guys could trade info on drilling holes and building heat pumps.

Good luck with hacking the air conditioners... I'd start with the small one, if I were you, or maybe be on the lookout for a really small one for real cheap. Last one I got was $10, somebody was having a yard sale... it's 5000 BTUs, a good size for initial experimenting... could even be used for hacking together a heat pump water heater.

Have fun,

-AC_Hacker

[MN Renovator]

If you could make an 8" hole that is 8 feet deep and could coil the width of the hole in the part of the soil that is deep enough for the geothermal, would you be able to use this for a smaller window unit 1 ton or smaller(12k) with multiple holes? I've used a rented post hole digger and you can get 12" wide holes or smaller holes depending on what you plan to do. I think it was $40 per day. Would, say, a tight coil at 6 feet deep be too shallow to run multiple coils in different holes spaced out? With an extension to the auger could probably go deeper than the standard auger depth if needed. Just an idea, it seems like far less work than grabbing a hand-held digger for the job.

[AC_Hacker]

Originally Posted by MN Renovator

If you could make an 8" hole that is 8 feet deep and could coil the width of the hole in the part of the soil that is deep enough for the geothermal, would you be able to use this for a smaller window unit 1 ton or smaller(12k) with multiple holes? I've used a rented post hole digger and you can get 12" wide holes or smaller holes depending on what you plan to do. I think it was $40 per day. Would, say, a tight coil at 6 feet deep be too shallow to run multiple coils in different holes spaced out? With an extension to the auger could probably go deeper than the standard auger depth if needed. Just an idea, it seems like far less work than grabbing a hand-held digger for the job.

If you are thinking along these lines, you really ought to look at the thread: Homemade Heat Pump Manifesto.

Even though it is impossibly long, it is quite possibly the best source of information you will find anywhere on the Internet on the topic of homemade Geothermal Heat Pumps.

If you find reading through the whole thing (those who have read through it, have found it to be very rewarding), there is a search engine that will help you zero in on particular information.

Regarding 6' holes, the depth below the frost line is the part that will be useful for geothermal heating. The deeper you go below the frost line, the more useful.

Regarding coiling, because heat flows rather slowly through earth, coiling may not help you as much as digging more holes.

There was a fellow that live not terribly far from your location, who was able to drill about a 3" hole about 23 feet deep by hand, using a manual auger and extensions. As I recall, he was digging in mid-winter and it took him three days of spare time.

If you had a series of 23 foot deep holes, you just might be able to get something interesting.

If you get going on this project, you might start another thread under the "Geothermal" topic heading, as it would be more appropriate than being under the Air Source Heat Pump thread...

Good luck with your project.

There are plenty of folks here on EcoRenovator with lots of good information and moral support...

Regards,

-AC_Hacker

[Geo NR Gee]

Originally Posted by AC_Hacker

Get in touch with another EcoRenovator who also lives in Washington, His forum name is Geo NR Gee, he's a real nice guy, I was up in Washington and met him, you guys could trade info on drilling holes and building heat pumps.



-AC_Hacker

Thanks AC for the kind words. Sparkchaser, if you ever come up this way, your'e welcome to stop by and check out my future hacks and drill machine. Today, I just picked up a AirTap heat pump for $50. I'm going to pull the top cover and see how it ticks. Costco - AirTap A7

[sparkchaser]

Wow, that was a great find! I followed the Costco link and also looked at the owners manual. Looks pretty much like a 115 vac window AC with a long loop in place of the outdoor side. That kind of makes me wonder if I could convert my smallest window unit. Though I don't think I want to cool off my pantry where the water heater is, though that would be great in the summer! Btw how long and what size tubing is the part that goes into the hw tank?

[Geo NR Gee]

Thanks Sparkchaser. I was thinking the same thing about it cooling down our garage. Great in the summer. About the only heat this time of year is from the furnace exhaust vent, car engine and hot water tank in the garage. At least the garage is insulated.

Insert dreams......
My thoughts are that the home of the future will have the refrigerators, freezers, hot water tank all connected moving heat around. Think of all the wasted heat from the refrigerator and freezer coils and compressor.

and another......
Too bad I couldn't have remote louvers on the vents in the attic where I could close them off and draw the heat from there. In the summer there is excess heat, but in the winter, not much.

I'm back....
But I am not sure what to do with it yet. It is after all a air source heat pump.

[sparkchaser]

Originally Posted by Geo NR Gee

Thanks Sparkchaser. I was thinking the same thing about it cooling down our garage. Great in the summer. About the only heat this time of year is from the furnace exhaust vent, car engine and hot water tank in the garage. At least the garage is insulated.

Insert dreams......
My thoughts are that the home of the future will have the refrigerators, freezers, hot water tank all connected moving heat around. Think of all the wasted heat from the refrigerator and freezer coils and compressor.

and another......
Too bad I couldn't have remote louvers on the vents in the attic where I could close them off and draw the heat from there. In the summer there is excess heat, but in the winter, not much.

I'm back....
But I am not sure what to do with it yet. It is after all a air source heat pump.

Well, you could do the vent thing, but my plan would be to run it more in the summer rather than winter. The pantry containing the water heater is next to the refrigerator, so I was thinking I would install two vents in the wall next to the fridge, top and bottom,and circulate air with a fan and get better economy from the fridge. That might even help in the winter maybe. I had thought for years (but never actually done it) to install two vents above and below the fridge to attic and crawlspace to keep fridge heat out of the kitchen in the summer and increase fridge economy in the winter too. My earlier question about the length of heat exchanger inserted int the hw heater could probably be answered by me measuring the existing condenser tubing length on my AC donor unit.

[Geo NR Gee]

Originally Posted by sparkchaser

Btw how long and what size tubing is the part that goes into the hw tank?

It looks like it will be about 10 ft, but I will have to let you know after I get a measuring tape. Here are some shots with the cover off.