Wisconsin My DIY GEO Install

It all started for me when I went to a customer appreciation day at our energy cooperative. At the event they gave out fliers about geothermal and explained the rebates for installing geothermal. I wasn't very interested at the time but thought to myself I wonder how geothermal actually works. I wanted to know the mechanics of how you can heat your house with dirt. That winter LP fuel price skyrocketed past $5 per gallon. I took evasive action and installed electric duct boosters, basically auxiliary electric heat. As it was cheaper to heat with electric then LP at that cost. I then decided to take a good look at alternatives.


Through reading about it and starting to understand it I decided to take the funds I had set aside for adding more solar pv panels and install a geothermal system. I payed a DIY contractor some funds to help me plan and design the system. The contractor gave me several good websites to read up on. They turned me on the caleffi indronics books and several other good reads. The contractor could not get my heat loss calcs done correctly so I ended up using hvac Calc software ($50 home owner fee) and did them my self. I also did calcs on my detached shop. At the time the plan was to use 2 separate 3 ton w2w units in the house and send whatever extra btus we had to the shop.


Then the purchasing began. I bought 1 Bosch unit through my supervising contractor and later found a good deal on another new one locally.


It took me several designs to get the ground loop nailed. I wanted to lay extra pipe and my contractor told me it wasn't needed so I ended up with a slight compromise and used 800' of 1" srd 11 per ton. And set it up with all the tails entering the building so I could valve it and manifold it inside.


Through reading several post from the great geothermal guys on this site I started to learn that gshp run more efficient with lower leaving Temps (heating mode). This got me thinking, I only heat the shop to 50 deg and if I had one unit for only the shop that unit would run very efficient with the lower temperature. (In floor heat already in the shop with a lp "boiler")


My heat loss was almost identical between the shop at 50 deg and the house at 70 deg.

So the math on 3 tons in each worked.


From there it became designing 2 separate systems. From the start I knew the house was going to be more involved then the shop. I had one room that was always 4 deg cooler then the rest of the house due to the way it was built and poor design on the 30 year old duct work. I wanted radiant floors and I wanted it zoned.


This started the pains taking process of installing uponor heat transfer panels and pex. Ran in a way that each room was zoned.



Also the prior owners had hard wood installed in part of the home and who ever did the install used a underlayment and put a nail every 4" in both directions. Every single nail had to be cut off flush. This was also why I chose uponor because it had some aluminum between the pex and the floor, my theory was it will hopefully keep the nails from causing any damage to the pex.


I found I could order geothermal pipe at the local diy big box store. So i ordered up some pipe and when it came in I had fun making a slinky table and making 6 slinkys from the 6 rolls of pipe.


I had a friend that was in the area with a big excavator that graciously offered to dig for me if I pay for fuel in the excavator. This would have been great for me but my supervising contractor had problems and could not deliver the parts on time so I had to cancel. After I finally got parts I had to rent a mini excavator. (I had no idea how hard it was to try and get someone to rent me a big excavator, no one wanted to)


It took me 2 long days to dig in the shop loop, lay the pipe and back fill leaving a mound of dirt above the trench so it would settle in. There was lots of hand digging as several areas crossed power lines ect...


A few weeks later I rented again and finished the house loops. Leaving a pretty big mess in the yard as you can only do so much with all the "extra" dirt I had. I did not want to pack it into the trench with the excavator. I chose to let the rain do most of the compaction for me.


I was a little nervous about kinked pipes with the weight of the back filled dirt.

Later on when I had some cut off pieces of srd 11 pipe laying on the shop floor one ended up under the tire of my truck. I was amazed that it didn't crush. But it heald up, I wasn't worried about the pipes so much after that.



Once the loops tails where in, the inside install was started again. The house install also included some remodeling. I'll post some pictures so you can see what we have. I'm sure it's not the most evolved system but it's mine.


A Thanks to Doc for showing me the buffer tank tee setup. My contractor told me this tee setup wouldn't work so I plumbed it both ways with a set of valves so I can show supporting data on it.


In hind sight I wish I had bought a buffer tank with a big fitting in the top to run the tee setup on but the one I have should be ok.


In the shop I'm using the cement floor as the "buffer" tank. I have enough flow to support this so it should work out well for me.



On the loop methanol antifreeze I didn't like the initial thought of having flammables in my home. But after reading on the flash points of mixed methanol and water I began to understand that it's not as dangerous as I thought. Between that , the cost, and better flow characteristics I went with it vs polypropylene glycol. In the end buying it and mixing it was pretty easy.

 

Just had time to get the yard flat and grass planted.



Won't let me add more pictures to the first post so I'll just drop some here.

 

nice!!!

 

Andy,

I would hire you in a minute! That inside work is better than a lot of commercial jobs I have seen. You should be our poster child for a well thought out and executed DIY.
Great job.
Eric

 

Here is the most recent picture. Still a little pipe insulation to get installed.


Thanks guys!

 

Very Nice!!!

 

You have done what I expected.

Good looking work.

Chilled water is easy.

Back in the Horse Pistol 10 out of all of August. It is only the 16th.

Mark

 

What was your contractor's reasoning why the buffer tank T, (or load direct, or buffer tank bypass) however you want to call it, does not work. Keep in mind that the pump between HP and Buffer tank must make enough flow to keep your HP happy. I see you have individual circulators for each zone. Any reason for that? Usually it is much more efficient to put a single variable speed pump there, with zones valves.

 

Doc I drew up a nice diagram of my design of the system. It showed the buffer tee. The contactor was consulting with another party and they both came back with "the buffer tank can't be piped like that". I didn't really ask why I just got it in my head that the tee should very very well but decided to pipe it both ways with valves so that when I get the wel logger I can show data on what works best.

As for the pumps it came down to cost for me. The wilo pump I would have needed would have cost me double the 3 smaller pumps. My pumps are ECM pumps so they only draw 44 watts max. They will be setup delta t so they will very in speed and power consumption to what is needed.

I have 2 manifold setups that are zoned one pump feeds each. With the 3rd pump feeding the air coil in the furnace.

Also on the wilo pumps I had very hard to try and figure out what all was needed. When you buy a wilo stratus pump do you also have to buy a module or something to make it delta p/t??

 

There is an external off switch which came extra, but a simplified version now come with each Stratos. John Manning at Phoenix Energy Supply makes a zone controller where the central zone pump turns off when none of the zones are calling for heat. The pump itself is pressure regulated. Constant pressure, variable speed. Funny that your contractor did not figure out what the Tee at the buffer tank does. It should save you 16% in energy, or allow you to increase the supply temps by 10F without any performance penalty, or reduce it by 10F in cooling mode, again without performance penalty.

 

Thank you for the clarification.
My HBX controller also turns off each pump if the zones on that pump are off.

In the winter my electric rate for this system is about half. So depending on how you look at it, it's kinda like doubling my COP.

 

Dual metering, and load control now installed and tested.

When I receive the rest of my pipe insulation it's time to remove the old a/c heat pump and put the gshp online.

Utility incentives forms filled out and sent. Plan to use the incentives for the wel data logger!

I'm amazed this old 2.5 ton unit still works. Every year I wonder if it will keep going and it has. But it's time to go now!

 

Took the day off work today. I was able to get the water coil into the furnace, pipe, and insulate it also.

Sounds easy right? But my well pressure tank sits right in the way of pulling the old A coil. Installing the new one required some custom duct work.

After that filled and purged the system.
Ground loop settled at 69-70 deg after a hour of run time. I think that's a good loop temperature?

I set the buffer tank temp target to 50deg and with everything running it ran about 53 and a hour later it was 52 so the new A coil looks to move slightly less btuh then the gshp so that looks good.

The new A coil pulls what I think looks to be a good amount of water out of the air so everything looks ok. If we get a batch of warm weather again well will see what it can do.

 

Can anyone suggest a good way to insulate the floor under the radiant heat?

I was thinking of making a air pocket with osb board then spray foaming that. I know it would be hard to get back into if I had problems.

Living with farm fields all the way around its hard to keep the mice out. I've got it sealed up pretty good to the point where we only see a few in the traps every winter. So I'm looking for something that's won't give the mice a new home. I E fiberglass is not a good option for me. They seam to stay away from spray foam.

Any thoughts?

 

As I posted in another thread, I'm using the Crete-Heat panels. Thicker ones for the basement and thinner for main and upper floors.
Since mine are embedded in concrete in the basement and gypcrete in the upper floors, no chance for any critters making it their home (I live in a rural area).
Of course, access is very difficult should there be a problem.

 

I would love to have that product In my home however being a retrofit job it wasn't in the budget. And tearing up the floor would make for a unhappy wife.

I know from trying it out it makes a great radiant ceiling. Not exactly what I need.

 

Andy:

You could staple up foil bubble foil faster than OSB. You only need to have greater R-value down from what ever the value of the floors.

Mark

 

I've read mixed reviews on foil bubble wrap.

 

I am not saying use it by itself, but as a barrier to foam to.

 

Today's lesson is don't freak out, check your instruments first.




Can anyone recommend a good thermometer for pt port use?

Thanks