The Homemade Heat Pump Manifesto

[AC_Hacker]

Originally Posted by tweeker

419 Lbs X 22.5 degrees = 9,427.5 BTU's

I think I figured it correctly ?

Can you draw a diagram of your setup?

It's hard for me to get an idea what you are doing from your description.

For instance, here's a diagram of my original COP test:

To do the test, I monitored the electricity consumption of my compressor by using a Kill-a-Watt meter. I discovered that the electricity consumption was changing a great deal and that I could not rely on the numbers printed on the side of the air conditioner, when I did my tests.

To do the test, I measured the temperature of the water in the barrel I labeled "HOT", every ten minutes, and I also logged the electricity consumed over each ten minute period. That gave me the information to calculate the COP for every ten minute interval.

I used the weight of the water in the "HOT" barrel only in my calculations, as that is where the useful work was being done.

-AC_Hacker

[tweeker]

Hi AC,

I was just thinking "I just figured out how to post pictures", and now I have to make a diagram/schematic like yours ? :-)

I am not that talented, BUT, I think I can draw one, in color, take a picture of it, and post it.

This is fun stuff for my kids and myself. We are more into the SOLAR stuff, but hacking A/C units and turning them into HP's is where my heart is.

Tweeker

[Acuario]

Hi AC,

I just came across your post about home made heat pumps. At the beginning of the year I did exactly that to heat my pool. I've written some (not all yet) of it up with photos of the project on my website costadoradaholiday.com/poolheater.html that describes how I modified the air conditioner and added a home made heat exchanger to heat the pool.

I love the idea of 'free' energy - I already use solar panels for both electric and hot water and am looking at other ways to use refrigeration to heat water for various projects.

Nigel

[AC_Hacker]

Originally Posted by Acuario

I've written som...that describes how I modified the air conditioner and added a home made heat exchanger to heat the pool.

Nigel,

Thank you for joining the conversation.

Excellent project!

However, I think that the greatest value in what you have done is to provide a direct path for people to hack mini-split type AC units for use in hydronic heating for home radiant heat. Right now, commercial units like that cost nearly $20,000. You have achieved a true breakthrough!

In anticipation that someone like yourself would join our conversation, I started a thread called Air Source Heat Pump (ASHP) Hacks & Mods. I think your project would be a perfect fit for that thread. I like your website you linked to very much, but if you saw fit to do a more detailed write up for the ASHP Hacks thread, I would think it would attract a very large audience. There is a respectable amount of traffic that is coming to EcoRenovator, and the heat pump hacking threads are a primary draw. I invite you to join us.

I really like your heat exchanger idea. I had the idea of a similar one, but my thoughts had not become reality, as yours have. Very good, very good.

I don't quite understand how you achieved a watertight seal on your heat exchangers. Could you go into a bit more detail on that aspect?

Also, I never heard of RS-44, that is a very good tip. However, it looks like it is Canada only.

Do you have any notion of the efficiency of your pool heaters?

How well do you anticipate the copper coils will survive pool water? Most pool heaters I see advertise special, unusual metal for the heat exchangers.

Great work, Nigel...

Best Regards,

-AC_Hacker

[Acuario]

I've added to your thread there and I've also written up more details of the heat exchanger construction.

I would guess RS44 (R-424A) is available anywhere. Here in Spain they suggest a couple of different replacements but the results seem to be that RS44 has better performance than the other replacements like R422D (MO29).

Nigel

[Blauhung]

FYI, picking up a used treadmill tomorrow. Looks like the motor would be something along the lines of this...


So, 2.9HP DC electric motor with power supply and PWM controller for $50. Sounds like a deal to me

[S-F]

Just thought I'd toss in a link to an interesting thread on Green Building Talk. about the possibility DIY GSHP.

http://www.greenbuildingtalk.com/For...c/Default.aspx

There are some interesting posts in there by junkhound. He basically flat out states that you can do it and all of the banter is like a dog chasing it's tail. Aside from that, there are a bunch of professional installers there who ultimately have to admit that it can be done and it isn't really secret magic for the initiated only.

[AC_Hacker]

Originally Posted by S-F

Just thought I'd toss in a link to an interesting thread on Green Building Talk. about the possibility DIY GSHP.

...as I recall, we pretty much established that DIY GSHP is possible, 747 blog posting ago.

There's an abundance of information available.

Several different approaches are known to work.

Tooling can be bought, rented or fabricated.

Now it's a matter of gaining the knowledge, getting the tools, summoning the gumption, and actually doing it.

Dogs chasing their tails? What a waste.

We have work to do...

Regards,

-AC_Hacker

[S-F]

Oh I know that this thread has positively proven it can be done with very little equipment or money. The point of posting that link was to show how DIY GSHP initiative meets professional installers. Really it looks like the major barrier for DIY is drilling or digging. What we need now is a DIY well drilling thread.

[AC_Hacker]

Originally Posted by Blauhung

FYI, picking up a used treadmill tomorrow. Looks like the motor would be something along the lines of this...

Did you get your treadmill?

Right after I read your post, I went out and found one too. $40, but not quite so good a motor as what you show (mine is 1.5 HP). I plan to use mine to run my band saw. Right now, it's set up for wood, and I want to be able to cut metals & plastics, which require slower speeds.

I did a 'biopsy' on the treadmill, finding what wires were actually needed for the motor and speed controller, and what wires were not. I isolated and removed the speed controller unit yesterday, today I pulled the motor and relevant hardware.

I didn't even take the treadmill out of the pickup, did all the surgery right in the bed of the pickup truck. Makes it easier to haul the remaining carcass off to scrap metal recycling.

BTW, did you get my message about the extra compressor(s)?

You asked, and I responded, but I never heard back from you.

-AC_Hacker.