The Homemade Heat Pump Manifesto

[mikecrowle]

Hello,

I am new to the forum. I have found that a lot of people have put a lot of good ideas and information here, and I wanted to be a part of it.

I am also interested in GSHP because I have recently purchased a home close to Montreal Canada (cold) with about 5 acres of land. And would like something cheaper and cleaner than the oil furnace that it has now.

I am thinking of a GSHP with horizontal coils (slinky). I would need a gas-to-air heat exchanger that I could connect to the existing ducts for the forced air. I think that I will be able to put the slinky coils in myself, saving a lot of money. The HP is another story as it gets a little more complex.

I would like some feedback on the idea of taking a window style A/C unit and building a water tight box around the cold side heat exchanger, then flooding the box with closed loop ground water. (I know that this heat exchanger is designed for air not liquid but this should still work. Of course the system would need a pump, isolation valves, expansion tank, maybe headers but you get the idea). I could mount the hot side in an appropriate place in my duct work and that should be it. Low cost and simple, but will it work?

Thanks for any advice and to all the people that have taken the time to share the knowledge.

MIke

[Xringer]

People have been dunking the cold side of small ACs into tanks to make cold water for CPU chip cooling..
water chiller

And it seems to work.. My guess is, it would work make hot water too.

I'm thinking of hacking a 4,000 BTU to make my own electric hot-water heater.

[AC_Hacker]

mikecrowle,

Welcome to the conversation!

Originally Posted by mikecrowle

I am also interested in GSHP because I have recently purchased a home close to Montreal Canada (cold) with about 5 acres of land. And would like something cheaper and cleaner than the oil furnace that it has now.

I am thinking of a GSHP with horizontal coils (slinky). I would need a gas-to-air heat exchanger that I could connect to the existing ducts for the forced air. I think that I will be able to put the slinky coils in myself, saving a lot of money.

You are correct, you can save some money with a GSHP, and the greatest expense involved is putting in the loop field. If you can do that yourself, you'll be way ahead.

Canada is very supportive of GSHP, and you may be able to get some good info there.

There's good info from the US, the best being the IGSHPA. Horrible name, but a wonderful resource. I recommend the manual page, where you will find all manner of 'state of the art' books on every aspect of GSHP installation for just about every part of N. America. The books are expensive, but there is NO FLUFF in them, it's all nuts & bolts info. I searched around on the web for about a year of spare time and learned a lot, before I broke down and bought the CLGS Installation Guide (#21020). I should have started there. You may be able to find the manual in a library, I was not so lucky.

They also have a Slinky Installation Guide(#21050), that would be applicable to your situation.

One thing I have heard about people who have properly sized their ground loops and then used a gas to air heat exchanger in their existing forced air system is that the air exchange rate is not right.

Heat Pumps make low-quality heat (AKA: low temp heat), so the air handling system needs to run just about all the time to provide the required BTUs to do the job. A properly designed system will allow for this. Not all HVAC guys are aware of the fine points of the system. Check this out.

So, even if you do the loop field yourself, it'll be a lot of work, even if you have or rent heavy equipment. The more you can reduce the heat loss of your house, the smaller your loop field will have to be, the lower the price will be, and the more satisfied you will be with the final result.

Many of the senior bloggers here at Ecorenovator will strongly encourage insulation upgrade as your very first step. I certainly agree.

There has been some very good work done on Superinsulation and on Passive House. I recommend spending some time understanding and applying these ideas prior to embarking on a GSHP or ASHP system.

Originally Posted by mikecrowle

The HP is another story as it gets a little more complex. I would like some feedback on the idea of taking a window style A/C unit and building a water tight box around the cold side heat exchanger, then flooding the box with closed loop ground water. (I know that this heat exchanger is designed for air not liquid but this should still work. Of course the system would need a pump, isolation valves, expansion tank, maybe headers but you get the idea). I could mount the hot side in an appropriate place in my duct work and that should be it. Low cost and simple, but will it work?

Sure, it should work. I really recommend doing a bit more homework and buying or making a refrigerant-to-water heat exchanger. The bought ones aren't so terribly expensive and will work a long time, ditto homemade ones. You'll need to learn the principles of extracting and re-pressurizing refrigerants, but it really isn't rocket science.

But what the hell, try the type you have envisioned. It will work for a while, and best of all, it may spark your interest in building a better one.

I'm not surprised that overclockers have rigged up air conditioners by putting the air-type evaporators in tanks of water, for the purpose of chilling their CPUs. But if the AC unit fails in that application, there is really very little consequence. If you are in the middle of a Canadian winter, and the unit fails, there could be serious consequences (As I write this, the temperature of Montreal will be 14 degrees in five days, that's serious cold).

Do some experimentation, do some studying of air conditioners and heat pumps, but keep a good back up heat source in the mean time.

Regards,

-AC_Hacker

[dawnpatrol]

Hi AC Hacker

Glad you have found time to post again..meanwhile I have been reading as musch as possible about GSHP stuff here and at Xtremesystems.org..all ver informative.

Here in the UK we have just had a cold spell, down to - 8 C over the last few weeks and my GSHP has been great..worked like a charm, ticking away and heating the 2500 sq foot house through underfloor heating in concrete floors. I put the system in myself, it uses 2 boreholes and a 7 kw heatpump..the bore holes go down to 100 m and cost about 9000 us dollars to have drilled...it was pretty messy and in the end they had to case the second one.

Having got the system in I want to optimise it's running..I really want a web accessed datalogger to get the various temperatures..I have read your information on loggers..have you got any further with them? (I know you have one you built yourself)

In England GSHP is in it's infancy, with very few installations and there is little knowledge in the mainstream.

Please keep going with this thread..it is very useful indeed.

Regards

[AC_Hacker]

dawnpatrol,

Thank you for your post & welcome to the conversation!

Originally Posted by dawnpatrol

Here in the UK we have just had a cold spell, down to - 8 C over the last few weeks and my GSHP has been great..worked like a charm, ticking away and heating the 2500 sq foot house through underfloor heating in concrete floors. I put the system in myself, it uses 2 boreholes and a 7 kw heatpump..the bore holes go down to 100 m and cost about 9000 us dollars to have drilled...it was pretty messy and in the end they had to case the second one.

That is a really good report. I heard about the awful weather you have been having, I recently set up a Free To Air (AKA:FTA) satellite TV system and Al Jazeera has done a wonderful job of getting world news out. How ever did I get along without it?

Sounds like your GSHP system is working just the way it is supposed to. You are ahead of me. When you say you put the system in yourself, how much of the job did you take on? Did you do the hydronic floors? Did you install the heat pump unit yourself? I'd really like to know more of your experience, and if you have any photos of the adventure, please feel free to include them. The "one picture is worth a thousand words" adage is certainly in effect here.

Originally Posted by dawnpatrol

Having got the system in I want to optimise it's running..I really want a web accessed datalogger to get the various temperatures..I have read your information on loggers..have you got any further with them? (I know you have one you built yourself)

Well, I am right in the middle of that now. I have bought a couple of boards from a place called Spark Fun and am on the verge of getting them to come to life.

The boards I have are:

1. Arduino USB Board

2. Arduino Ethernet Shield

The ethernet shield board plugs into the Arduino board. On the Arduino site there are samples of code that you can load onto the Arduino board to get demo-level performance. There is code to get the Ethernet shield to act as a web server, and code to get the Arduino board to read from a string of "1-wire" sensors. So that is where I am at right now. I'm going to a meeting tonight where some of the local Uber-Geeks quaff beer and share their knowledge.

I'll let you know what I find out.

Originally Posted by dawnpatrol

Please keep going with this thread..it is very useful indeed.

I got interrupted by the Free-To-Air satellite project,and by the acquisition of a small lathe and a small milling machine, which is still laying in parts on the basement floor.

I'm also in the middle of deep destruction of my kitchen.

So many projects, so little time.

And as if that weren't enough, I came home two days ago and there was an abandoned orphan on my door step... and abandoned de-humidifier. I guess the word is getting around!

Best Regards,

-AC_Hacker

%%%%%%%

[dawnpatrol]

A friend of mine is a plumber and between us we did the whole thing, floors, heatpump, plumbing. I contracted a rig to do the drilling but then did all the pipe work and manifolds. I went on the installer course at the heat pump supplier and then relayed the information to my plumber. We connected it all up but then weren´t allowed to commision it as it would invalidate the warranty..that was hard as I just wanted to get it going!

Now the bad news..I have had 2 new compressors (under warranty) but it seems that was a freak..the first was caused by a oil leak which locked the compressor solid and the second by not getting all the oil out when they replaced it first time. But now all is well and hopefully will be for the next 25 years!! I spend half the month away (at the moment in Brazil), so it has to be reliable as otherwise my family would go nuts.

I will do a proper write up and find some pictures to put up.

I have been looking at those boards you have got and I will be interested to see how you get on with them..if it is positive I will go the same way. I was thinking that what we really need is a networked kill-a-watt meter..then we could monitor everything in the house. Maybe we should carry on the data logger info in your other thread, to keep it all in one place?

A friend of mine wants to use a lake as a heat source..3500 sq ft house..lake 75m by 50m by 10m (deep)..another friend of mine (who installs systems) put one in a lake..but in the summer it was so warm the heatpump was producing masses of energy. I have a 2000 llitre rainwater tank and am thinking of using that as a heat source. At least it is burried so I can control the solar gain to it, with a lake you can´t really put a sunscreen over it! I have seen a skip full of water being used, admittedly as a demonstration, but it is a cheap valuable source, particularly if you supplement it with solar ie heat it up using a solar collector. If you look at the gshp on Mt Best, Australia, this is what he has done. He also runs his gshp off his genertated electricity, though I don´t know how he gets over the startup currrents..on mine it is 40 amp at 220 volt (that´s with a soft start on single phase)

An ideal plot of land would have a running stream through it, plenty of energy for electricity and heat for a gshp. I have been told that in Scandanavia there is a system where they use solar gain in the summer to heat up water in an underground cavern and then extract it in the winter..apparently for a whole town! I must try and get some info on it.

I am beginning to learn that a gshp is all about the heat source..the rest is just plumbing and refrigeration.

I like the look of the milling machine, luckily I have access to a friends..

[cholcombe]

AC_Hacker: I just bought that same Grizzly Mill and I'm really enjoying it. It has helped me immensely in building a solid wood bed frame.

[spcander]

How about a galvanized pipe slightly larger than the well pipe. Cut the pipe in half, and weld on hinges. Insert pipe to be welded, and heat the entire assembly.
Keep up the awesome posts, looking forward to more posts

[AC_Hacker]

Originally Posted by spcander

How about a galvanized pipe slightly larger than the well pipe. Cut the pipe in half, and weld on hinges. Insert pipe to be welded, and heat the entire assembly.
Keep up the awesome posts, looking forward to more posts

I'm afraid I don't understand what this is in reference to? Please explain.

Regards,

-AC_Hacker

[spcander]

Originally Posted by AC_Hacker

I'm afraid I don't understand what this is in reference to? Please explain.

Regards,

-AC_Hacker

Hi AC_Hacker:

Sorry if my post was out of context. I was refering to the post about how you welded the plastic well pipe for the geothermal project. Please keep up the posts!!!

Thanks