Thursday, January 01, 2009

Solar Geothermal - Part II

The day after Christmas, the geothermal installer called me (waking me up) and told me the well drillers were on the way. I began to protest, but then reconsidered since I had been waiting for months to get them on site. Actually I had feared that with the onset of mud season, our window of opportunity might have passed. The road was in terrible shape, but if the drillers were rarin' and ready to give it a try, so was I... I thought the road might just be in good enough shape to push and pull a well drilling rig to the top of the hill. I was ready for some fun.

Miraculously, the top heavy 60,000lb drilling rig teetered slowly up the dirt road to the top of the hill on its own power without going wheels up, but then it got mired in the mud at the top. I used my backhoe to pull him free, but the last 20 yards proved to be even tougher. The clay on top of our hill is slicker than fish snot, and it was starting to rain. The backhoe was not up to the task, so I got the bulldozer and shoved him up the bank into the front yard. I'll have to say that the driver of the well rig (the owner's nephew - 25 years old?) had a fine sense of adventure. After he was in position, he called it a day and rode home with his helper in their Ford truck.

A few days later, they showed back up ready to drill holes. I loaned them some timber cut-offs to stack under their front outrigger because the hydraulic outrigger didn't have enough extension to level the drilling rig on the hill side. It all looked a bit precarious, but the young drill operator was un-fazed. In the picture to the right, you can see one of the carousels holding the rusty drill extensions. I believe they had twelve of these 25 foot drill extensions, which enabled them to drill to 300 feet if need be. Our geothermal contractor usually bores to 150 feet, but he suggested we go another 50 feet in each well on our job to compensate for the height of the hill. His goal was to strike water, because if your geothermal wells are wet, the heat transfer to the surrounding soil is more effective.

Our whole family watched with great anticipation from a second floor window as they drilled the first hole. They began with a 6" bit for drilling dirt, and as soon as they hit the first layer of rock, they extracted that bit and replaced it with a 4" rock bit. The kids and I documented the color of the cuttings that were blown from the hole, as the drill progressed downward. Every 25 feet, the men operating the rig had to add another extension to the drill in the ground, so we could estimate the depth of the drill at any time. Red, brown, yellow, gray, blue-gray... and then from 50 feet and beyond, our notes recorded only varying shades of gray. We saw dark gray and wondered hopefully if that meant water.

After the drill reached 200 feet, the operators began extracting the 25 foot segments one at a time. The first three segments to emerge from the hole were no longer rusty - but instead shiny gray steel. The last five segments to come out had mud stuck to them - the operator confirmed that we had hit water at around 100 feet! After removing the drill from the hole, the operators inserted a 200 foot long loop of 3/4" black PE pipe all the way to the bottom. The loop was actually two pipes with a u-fitting fused to the bottom, so the total length of pipe in each hole is 400 feet.

The next three holes went exactly as the first had. The kids lost interest after the first hole, but I was captivated until the end. When completed, this geothermal system (aka ground source heat pump) will effectively multiply the energy of our solar panels by a factor of at least four - how could I not be excited about that?!

Rather than backfill with grout, the well drillers filled the holes back up with the cuttings from the boring process. I have my doubts about the thermal transfer efficiency of the cuttings (only about 30% of them went back into the hole!), but I speculate that the cuttings never went all the way down the hole and that the bottom of the hole is immersed in water. I think it will work just fine. I tried pouring some water into the holes after the drillers left, and the fine powdery cuttings in the top 5 feet of the hole turned to clay and would let no more water flow in. With the tops of the holes sealed so well, I doubt there is any chance of contaminating ground water with surface runoff - which I believe is the main reason some installers use grout.

A few weeks earlier, I had begun upgrading our inverter system, so it would have the wattage necessary to start the heat pumps. Unfortunately, one of the two new Outback inverters was dead - right out of the box. Not usually a problem since these have a two year warranty, but I had bought these inverters over two years ago and had left them sitting in the box since I didn't yet need the extra capacity. Slightly concerned about how they would treat the warranty situation, I called Outback, and they agreed to send me new boards for the bad inverter - free of charge. This is a class A company. Due to the aborted upgrade, our inverter system looked like the picture on the left while I waited for the boards to show up. Mind you - it was still functioning the whole time!

The boards showed up and I installed them in the inverter. The directions for installing the boards, written for professional installers not home owners (I consider myself somewhere in between), were nonetheless some of the most amusing technical writings I have ever read. One passage read... "Before getting into the unit you need to make sure you do not have a static charge built up on you or your clothes. The safest way to accomplish this is to stand naked in a mud puddle while disassembling the inverter. Another method would be to...(goes on to describe more conventional ways to avoid static discharge)" . I like a company that takes their customers seriously, while maintaining a sense of humor! With the help of the well written instructions, I successfully completed the inverter surgery without disrobing. Here's a picture of the upgraded system with four functioning inverters - capable of providing 14.4 Kilowatts of continuous power!

Incidentally, the heat pumps will collectively consume less than 4 Kw while running at full power (less than 30% of the inverter system's capacity). I upgraded our system to ensure that the lock rotor amps (startup current) of the heat pump compressors will not exceed the peak capability of the inverters. As an added safety margin, the geothermal contractor tells me that Waterfurnace (the brand of geothermal heat pumps we will be using) are supportive of this unique installation and will provide some special soft-start electronics for the compressor motors.

With all of these preparations, I am confident that these inverters will be able to start and run the two 2 ton units. Some day, running geothermal systems with off grid solar power may be common place. In the mean time, I'm happy to be the guinea pig.


Blogger Jeff said...

I like the idea of the sustainable home. Did you look at wind turbines as opposed to solar? I was in town over Christmas but did not get enough time to stop by. I will be back in the Spring / Summer and would love a tour!

January 3, 2009 at 10:59 AM  
Blogger Book Hunter said...

I am curious about a few things on this project. First, where do you obtain your water from? A well or a county water district supply line?

Second, if you struck water and have your geothermal piping put into four wells, why did you not have a water well pump installed into one of the holes as well?

Third, I would imagine drilling as deep as you did cost quite a bit for one well, but to drill four must have been rather costly. How did you budget that expense?

My wife and I are considering totally off grid living, though I too was stumped about how to have an air conditioning equivalent that didn't consume more power than we could easily produce. Your blog gives me some ideas that I can share with my wife. Thank you for sharing your experiences.

January 6, 2009 at 8:46 AM  
Blogger Kevin Pentz said...

Hello, my name is kevin and I live in Richmond KY. I've stumbled across your blog because I'm interested in learning to build a timber frame home. My wife and I are hoping to buy forested land at some point and I'd like to use timbers from the property to build a timber frame house, but I would also like to incorporate straw bale insulation into the design. I would love to come out and see the work you have done on your place.

Also did you give thought to staying connected to the energy grid, but using a net metering system? Forgive me if you talked about this on one of your posts, but I haven't yet read them all.

Take Care, (my e-mail is

January 7, 2009 at 4:46 PM  
Blogger oldmilwaukee said...

short answer, I would like to incorporate wind at some point, but for our region, solar seemed to make the most sense to start with.

@book hunter
water is from a dug well. (I have a previous post on water supply - and several more to come) I trust water near the surface more than water from the Ordivician era. :) all the same, I would have put an extra well for water in when the geothermal guys were here, if the budget had permitted. geothermal is costly, and wells are more costly than trenches. see my previous post on this topic, air conditioning was a non-negotiable with my wife - budget or no budget.

I am finding that accommodating modern conveniences costs about three times as much off-grid as it does on-grid. You just have to decide how much it is worth to you I guess. In the end, most vote to stay on the grid whereas some vote to go off grid and give up some conveniences. You don't see a lot of people go off the grid and try to keep the conveniences. That's what I'm trying to do.

I dropped you a private email. Our new house site was never connected to the grid. I opted not to connect to the grid for philosophical reasons, backed up with some weak justifications such as:

1. why should I sell them clean peak demand electricity for 7 cents a Kwhr, when it costs me 21 cents to make it? when they offer to pay me what it's worth, then we'll talk.

2. I have a system about 10 times as reliable as the grid, why would I want to run the risk of connecting to the grid? For instance, we lost two refrigerators and two PC motherboards to brown-outs on the grid at our mobile home. I would hate to lose my inverter system to their crappy power. If they blew my system up, they would never pay you for it. OTOH, you must carry $100,000 in liability insurance to protect the power company's equipment. What's wrong with this picture?

January 8, 2009 at 11:34 AM  
Blogger oldmilwaukee said...

BTW, thanks for the comments!!! Your interest keeps me interested in sharing this project on the internet!

January 8, 2009 at 11:36 AM  
Anonymous AMG said...

Now I know why your drive was in such a mess! : ) Keep sharing the project - I find it very informative and amusing.

January 12, 2009 at 9:55 PM  
Anonymous Anonymous said...

I can't tell ya the hours I have spent the past month or so reading and re-reading your blog(s). Too many, with that said, I have enjoyed every minute. It is an inspiration!
We live in Louisville, but are proud of our Eastern,KY roots. My wife,is the product of Appalachia as well.
We(ok,I)needed a shed/barn(MANCAVE I have 3 daughters)the day we moved into our current house. So, when IKE(the storm that was)blew in/out of town last fall, my potential timberframe fell all around me!
So, I have read several books,blogs and whatever I can find. If things go right I will get down to Paris, TN for the fall class.
Look forward to more on your blog(s) as well.

January 16, 2009 at 7:31 PM  
Anonymous sandi said...

Your geo project makes it all look so easy! We wish the wells were financially viable up here in Alsak; poor Tyson spent a full week, around the clock, with his rump glued to the excavator seat digging our horizontal trenches. But there is no doubt we LOVE our system. It was dreamy, even at 20 below a few weeks ago!

January 21, 2009 at 6:05 PM  
Anonymous Louisville Cousin said...

I've toured your house once with your Mom and my Dad. I now enjoy reading about your progress.

The love you have built into your home shows. Thanks for sharing.

January 31, 2009 at 11:08 PM  
Anonymous Jim K in PA said...

Tom - looking great. I saw you mention using a wood gasser for heat somewhere. Check out what I just did at our place.

It's a whole new world.

February 3, 2009 at 4:59 PM  
Blogger oldmilwaukee said...


DO SIGN UP FOR THE WORKSHOP IN TN. You will love it. Obviously, for me, it was a life-course-altering event. Let me know when you are back visiting in the better half of KY - we would be more than glad to show you the house and talk timber frames.


I promise to improve the road... at some point!


Glad to hear your system works. I remember reading about Tyson's ordeal on his blog. If there were more hours in the day, I might have tried to install our own system. Sounds like he did a good job if you are warm in Alaska! My geothermal installer hasn't been back, but that's OK - I haven't given him a single penny, yet there are two geothermal units sitting in crates in my basement. At some point, I'd like to see them working - AC is the biggest concern this summer. BTW, we enjoyed your visit.


come back and I will cook you a pizza!

Jim K,

so you ARE the same Jim K in PA! I have been lurking on the forums too. Saw your handle there and wondered if it was the same "buckingham slate" guy. As a matter of fact, I haven't updated this blog in a few weeks because I've been bustin my butt, installing our wood gassifier. It's a Tarm. I'm starting w/o water storage, but I plan to add it next season. One thing at a time. I think I'll be ready to start my first fire within a week. Pressure testing all of my sweat joints for leaks today - so far, only one leaking sweat joint and a couple of loose pex fittings. More on this later. I need to go back and read your web page on the Garn - I trust you like it? I read the last page - I arrived at a gassifier by following much the same path as you.


February 4, 2009 at 2:33 PM  
Blogger Chris said...

I just wanted to drop you a line saying I've now read every old post on your blog and the house is absolutely amazing! There are a few things you've done that I want to try to incorporate into my current home. I check your blog frequently for updates. Keep up the work on the house and the blogging!

February 5, 2009 at 10:08 AM  
Blogger Chad said...

I had a visit with Phil yesterday as I fixed a broken optical drive on his laptop. Your project worked its way into the conversation and I must say I'm truly impressed with what your doing. I make my way down to Huntington, WV for discgolf at least once a year (via the AA) I would love to stop by and see how the finished product is turning out (looks like your just about done). I mentioned this to your brother and he promptly stated I would be running a risk of getting shot. Soooo, just thought I would ask permission first.

I was talking with some of my eco-friendly buddies here in Cinci last night and I brought up your blog to them. First question out of their mouths were about geothermal heating. "Matter of fact..", I said "they just put it in last month".

Very entertaining reading, keep up the hard work!

February 5, 2009 at 12:40 PM  
Blogger Chad said...

Ohhhh I nearly forgot .. I haven't made it all the way through your archive yet, so I dont know if you have come up with a cooling option yet. One of my best friends just opened up a Segway store in cincinnati. They had a great idea for cooling their storefront. A BIG ASS FAN! No fooln' .. its really called a big ass fan. They were able to talk the company out of one for free as the whole segway / BAF green movement are compatible. Of course they are also a demo site for the company in exchange for the free fan. Thought you might consider this an option, or at least something cool to google.

February 5, 2009 at 12:54 PM  
Blogger Chad said...

February 5, 2009 at 1:02 PM  
Anonymous Jim K in PA said...

"so you ARE the same Jim K in PA!"

Yep - blabbing my mouth all over the 'net, as usual. ;~)

"I have been lurking on the forums too."

Poke your head out once in a while over there! It's a good bunch of very knowledgeable people, with a few curmudgeons thrown in.

"I've been bustin my butt, installing our wood gassifier. It's a Tarm. I'm starting w/o water storage, but I plan to add it next season."

Fantastic. I figured you got the TARM by the description. I thought long and hard about the divorced systems, and ultimately decided that the GARN was our best solution. Far less complex, integrated storage for max transfer efficiency, and stupid simple to operate. We love it. When you add storage, go big or go home! I have almost 2000 gallons, and its great. I would have gone with 3000 if I could have afforded it.

The only other gasser I would be tempted by now is the Frohling.

"I think I'll be ready to start my first fire within a week. Pressure testing all of my sweat joints for leaks today - so far, only one leaking sweat joint and a couple of loose pex fittings. More on this later."

Awesome. I look forward to the update.

"I need to go back and read your web page on the Garn - I trust you like it? I read the last page - I arrived at a gassifier by following much the same path as you."

Yep - we love it, and have no regrets. Wife and sons ran it for several weeks when I was unable to while recovering from eye surgery. Piece 'o cake. No fiddling with air flow adjustments, no smoke in the shed, and excellent fuel efficiency.

Hit me via email if I can be of any help.

February 5, 2009 at 4:20 PM  
Blogger oldmilwaukee said...

Chris, thank you. if you do want to inc. some of these things in your house and need more detail than I provide here, just ask away and I can share my limited experience.

Chad, I will check out those fans. I think the geothermal will provide all of my cooling needs, but who knows. Get my number from Phillip and give me a call if you are heading this way. Let me know if you are bringing guests so I will know how many rounds to load. ha ha.

Jim K, I like your reasoning on the integral water storage. Makes a lot of sense. I honestly didn't know about the Garn when I bought the Tarm. What convinced me was there were 20 year old Tarm boilers for sale on ebay. Haven't seen too many wood boiler co's that have been around that long, let alone boilers that still work. :) Please check out my next blog post when you have time/interest - I just uploaded my Tarm story/pictures. Right now, the Tarm is going full bore, as I am dumping lots of BTUs into the basement which has 500,000 pounds of concrete, counting the footers.

February 10, 2009 at 7:24 PM  
Anonymous Anonymous said...

This comment has been removed by a blog administrator.

July 26, 2011 at 8:04 PM  

Post a Comment

<< Home