The Homemade Heat Pump Manifesto

[AC_Hacker]

Originally Posted by dremd

What a waste of good refrigerant, I couldn't believe my eyes.

What a waste of a good ozone layer!

The Aussies were very much affected by the ozone depletion thing, much more that those of us in the USA.

They were having problems with sheep getting cataracts, and they mandated the wearing of wide-brimmed hats by school children at recess.

Oddly, the government of Australia recently defeated a bill by 31 to 6, that would have put that country on the road to preparing for Peak Oil.

Maybe they're planning on seceding from the environment?

-AC_Hacker

[AC_Hacker]

Originally Posted by Xringer

It's interesting there are two factory charging points on that AC.. Wonder why not just one?

I wasn't sure what they call them in the industry, so I called them 'charging points', because they are used temporarily to charge the unit in the factory, then they are brazed shut, which is cheaper than installing two Schrader valves. It might be more reliable, too.

But the one on the suction side of the compressor is for the Low-Side gauge, and the one on the discharge side of the compressor is for the High-Side gauge. When they charge the unit, they put the initial charge into the high side, and then they start the compressor and finish the charge, putting the refrigerant in through the low-side.

As far as purging the system with R-22, it sounds like the Red-Neck way.

-AC_Hacker

%%%%%%%

[cold in Maine]

Hello! I am very interested in your project. I also have an old house (circa 1870 cape) that I am trying to make more efficient. I would like to do something with a geothermal system, but there really isn't anyone in this area that has much experience. Those I have talked to say that it is too hard to retrofit an old house and that the only way to do a system is to bore wells, which I don't feel capable of doing myself. From what I have read, it seems like I should be able to put radiant heat either on the bottom of the existing wood floors, or on top of my basement cement slab (in a new layer of cement). Some people have told me that I won't get enough heat through the multiple layers of wood in the floors, or from the basement, but since I also have wood stoves I am just hoping for the geothermal to keep the house around 55 or so, and it seems like it should be able to do that. Could you give me any feedback on that?
I also am interested in a trench system, since I think I can do that myself. In talking about the ground source loop, you said

Here in Oregon, where I live, an 80 foot long, three foot wide,
by four foot deep trench containing about 300 feet of slinky
loops of plastic pipe, per Ton (12,000 BTU/hr) is required.
(* or *)
Two hundred feet of borehole per Ton is required.

Did you do both a trench and a borehole? Or was that one or the other? Any suggestions on how I could estimate the length of trench and slinky loops I would need?

Thanks for any info you can give me!

[AC_Hacker]

cold in Maine,

Originally Posted by cold in Maine

Hello! I am very interested in your project. I also have an old house (circa 1870 cape) that I am trying to make more efficient. I would like to do something with a geothermal system, but there really isn't anyone in this area that has much experience. Those I have talked to say that it is too hard to retrofit an old house and that the only way to do a system is to bore wells, which I don't feel capable of doing myself.

It gets pretty cold in Maine, as your blog-name implies, you know this already.

My project is actually progressing along two different fronts. One part of the project which you are speaking of is the Ground Source Heat Pump and the radiant floor heat.

The other part I have mentioned previously in this thread, but I haven't gone into as much detail, is the insulation part. Insulation has been proceeding slowly for some years now. My friends think that I am also going overboard on the house insulation. The way I see it, I am only being rational.

I started by tearing off the lathe & plaster from the un-insulated walls and putting insulation in the wall cavities. At first I was filling the four inch space with R-13 fiberglass, which I thought at the time was pretty good insulation, a big improvement from no insulation at all...

I have since come to realize just how important insulation is, and how quietly and reliably it saves heat and money. I have also become much more knowledgeable regarding our energy future, and have been motivated to change my insulation strategy. Now I am thickening the wall from 4 inches to 6 inches, and layering in styrofoam insulation, which is much better per inch than fiberglass. Counting the sheetrock + the 6 inches of Styrofoam + the outside sheathing + the siding, my walls are just about R-30.

All this and I live in Western Oregon where the winters are much milder than in the beautiful state of Maine. For instance, here the frost line is defined as 8" deep... how does that compare to Maine?

Originally Posted by cold in Maine

From what I have read, it seems like I should be able to put radiant heat either on the bottom of the existing wood floors, or on top of my basement cement slab (in a new layer of cement). Some people have told me that I won't get enough heat through the multiple layers of wood in the floors, or from the basement, but since I also have wood stoves I am just hoping for the geothermal to keep the house around 55 or so, and it seems like it should be able to do that. Could you give me any feedback on that?

Under floor hydronic heating works poorly with a heat pump. However, if your primary heat is to be wood heat, supplemented by geothermal, it might work out.

An any case, If I were you, I would give primary attention to insulation in your walls, in tightening up any leaks around doorways and windows, etc. If your windows are old and loose, replace them with modern tight windows. This will be money well spent, no matter what kind of heating you end up with.

On EcoRenovator, there are many people doing all these things, so you'll have plenty of tips & info.





I'd suspect that if you spoke to installers there in Maine, they are assuming that you intend to use geothermal to heat to about 70 degrees F. If you're only heating to 55 degrees, the delta (difference between the inside temperature minus the outside temperature) would be lower, so the heat would not leak out so fast.

Originally Posted by cold in Maine

I also am interested in a trench system, since I think I can do that myself. In talking about the ground source loop, you said

Originally Posted by cold in Maine

Did you do both a trench and a borehole? Or was that one or the other? Any suggestions on how I could estimate the length of trench and slinky loops I would need?

If you're considering trenches, you can't ignore the soil conditions in your area. I'm not so sure how it is in your area, but I seem to recall that Robert Frost wrote quite a few poems about all the big rocks in the New England soil. Call some local installers ask them if trenches are possible in your area.

Regarding the borehole and trench estimates, I came up with those figures by talking to many local geothermal installers and well drillers and by paying to go to certification conferences for geothermal installers... they were the voice of experience, and their estimates were based on local conditions and intended for local installations. In addition to talking to people in the trade, I also followed a proceedure that is used in the GSHP world to test the thermal conductivity of a borehole, my results compared favorably with local estimates.

You can be pretty confidant that your conditions will be different.

But I was concentrating on boreholes, and the shallow connecting trenches were, in fact trenches. Being as how they are so shallow, they may work against me, that's why I insulated (some of) them.

They usually estimate the heating requirements based on the square footage of a house. This is really just a rule of thumb that seems to work OK for oil and gas heat, since in that world the estimates are usually increased by 50% and the furnace is sized accordingly. If you increase the size of a furnace by 50%, you might change the cost of the installation by a few hundred dollars. If you increase the size of a geothermal loop field by 50%, the change in cost of installation may be in the tens of thousands of dollars.

So obviously, it's important to know what your heating requirement (AKA: heat load) is. There are computer programs, some of them free, that would give you a very close value for your heat loss.

Here's a pretty good one that you can use as a trial, or if you just intend to use it for your own house, it's $50.

HVAC-Calc

Also, if you heat by gas or oil or electric, you can convert the amount used to BTUs per hour, and calculate a monthly average.

Probably best to do both and compare them.

But people in New England are well known for doing things their own wan and coming up the winner...

So however you proceed, I sincerely wish you the best of luck. Let us know how things go.

Best Regards,

-AC_Hacker

[dremd]

C 25 appears to work fine with Coper pipes and silver solder.
So if you've got a buddy with MIG tanks, then your good.

[AC_Hacker]

Originally Posted by dremd

C 25 appears to work fine with Coper pipes and silver solder.
So if you've got a buddy with MIG tanks, then your good.

dremd,

Thanks for running the test.

I have done silver soldering before, and I was able to do it easily with a regular propane torch.

When I tried to braze refrigeration line, the propane didn't get things hot enough. I found it necessary to use MAPP gas and a turbo torch. The turbo torch and propane still would not work.

So I have to heat everything up really hot, to cherry red...

Were you getting the copper heated to cherry red in your test? It could surely make a difference in oxidation.

Thanks,

-AC_Hacker

[dremd]

Originally Posted by AC_Hacker

dremd,


Were you getting the copper heated to cherry red in your test? It could surely make a difference in oxidation.

Thanks,

-AC_Hacker

Yup cherry red-white, Melted first test in to a heap.
Only Torches I own are Oxygen/ Acetylene.
No Black crap on the inside.

[AC_Hacker]

Originally Posted by dremd

Yup cherry red-white, Melted first test in to a heap.
Only Torches I own are Oxygen/ Acetylene.
No Black crap on the inside.

I think we may have a winner!

-AC_Hacker

[Xringer]

Hey AC Hacker,
If you needed to measure the R410A pressure in your Sanyo, what would be the procedure?
And how would the cooling and heating modes effect the pressure readings at the service port?

[Christian Nelson]

New here, I have a propane boiler I installed myself this past year. I also installed my hydronic heating system, used slant fin's heat loss estimator, and sized my system. I have a combination of infloor radiant, and baseboards, using hot water. I sized the radiators to run at 140 degrees, so a bit large, but I was making the runs with PEX instead of copper, so I didn't want to run any hotter than 170, plus I wanted to augment with solar, so I wanted it to be as forgiving as possible.

Anyhow, I have had no end of fits dealing with HVAC people, the boiler I got, I bought from PEXsupply.com, and it needed to be fine tuned for optimum efficiency, and I don't have a meter. Well, I got the answer form almost every HVAC person "you bought it on the internet, have the internet adjust it for ya" and they wouldn't come out to do it.. So, I am buying a meter myself I guess.

Anyhow, pretty happy with the system so far, and hoping to set up the solar shed with under ground storage tanks this summer. I found this DIY VERY interesting, and was thinking of maybe using a heatpump to keep my storage tank warm in the cloudy days of winter when the solar isn't helping much, and at best not using the propane boiler much.

My question is about the deep well drilling loops, I noticed you made about 4 fusion welds to make the "U" to come back up, and was wondering why you didn't heat them up and bend them into a "U" instead. Maybe drill the hole a wee bit bigger.

Or, I was looking at SC80 PVC, and simply putting "U" fittings and gluing them at the bottom I would think would work. We use PVC for sewer pipe, and other things under ground, why not this? Electricians have a sort of blanket they use for heating up PVC conduit (SC80) and you can make a fairly tight 180 once it is warmed up without kinking the things. Would this poly pipe you are using be similar?

Also, I very much agree with the insulate the nonsense out of your house thing.

I've been slowly injecting slow rise foam in my walls, zero insulation in them before.

I live in Wisconsin, with the frost line of 34" house built in 1908.