Building a House for the GARN

[Father John]

Having made the decision to heat the radiant floors of our monastery with a Garn boiler, we began the preparations today by digging the footers for a boiler room addition and the trench to connect this addition to the current kitchen basement.

It is too bad we didn't hear about the Garn and its impressive size earlier this year, when I thought we had finished the landscaping of the area around the kitchen. We had had the naive idea that any wood boiler system could fit in the kitchen basement, but since we think the Garn will satisfy our heating needs for many years to come, it seemed worth doing it right and building it its own structure.

The building will be 16'x32' and attached to one end of the garage, but separated by an 8" concrete firewall and fire-rated steel door. The garage itself can be reached by way of a covered walk, so going out to tend the boiler shouldn't be too much of a penance.

Our generator was put at the end of the garage for the same reason, which is a great pity since I will have to redo the nice concrete pad and conduits somewhere else.

 

[Father John]

Here are a couple of photos of the actual foundation trenches and the trench for the lines to the basement.

 

[Eric Johnson]

Father John, I'd like to introduce you to Pook, our resident energy visionary and jazz critic.

I remain amazed that you can heat such a large building with a 144K btu oil boiler, since I'm heating somewhat less space with a somewhat bigger boiler. But I went to your website today and saw the construction photos, so obviously you've designed energy efficiency into the buildings. And the climate in Southwest Virginia is considerably milder than what we see up here along the northern border. So I'm looking forward to seeing your progress.

Are you doing this work yourself? If so, do you have help. Judging from the website photos, I'm sure you guys will do a first class job.

 

[Father John]

We are doing the work ourselves, with occasional assistance when we really get in over our heads. Today a loan of a Kubota mini-excavator was all the help needed digging, so much easier than the old fashioned way.

The truth is since we got all the heat turned on a couple of years ago, we haven't had a real winter. Last winter was extremely mild, except for a brief period in early spring, so I really don't think that one 144k btu boiler will suffice when winter truly returns. On the other hand, we have over 1500 yards of concrete in this building, as well as several million pounds of aerated concrete block and limestone, so if we are careful to turn the heat on early enough in fall, and not let it get cool, the thermal mass of the building is rather enormous. In the ice storm earlier this year we lost power for a week (the erstwhile generator was not yet hooked up), and the temperatures dropped into the teens and twenties, and most zones in the building lost only 7-10 degrees over that time.

On the other hand... getting those ten degrees back into the building after power returned was an exercise in patience.

 

[Eric Johnson]

Well then you're probably a good candidate for the Garn, because getting all that water up to temp is going to take some sustained firing. But once you get the ball rolling......

Any solar?

 

[brad068]

Father John,

I 'm glad to see that you chose the Garn. You will not be disappointed. These units are awesome. I constructed one of them myself after seeing two older units (over 20 years old) and one new unit in operation. They're big, they're expensive, but they're simple. You will love the induced draft. Don't let them crude cold war downdraft gasifiers rain on your parade. You made the right choice.

 

[Father John]

Well, in spite of an inch or two of snow in the night, which was unexpected, we got the footer poured today for the Garn room. Next item on the list will be to put in a pair of 1 1/2" PEX lines and insulate the same to carry the hot water from the Garn to the current boiler loop. Does anyone know if the already insulated lines available (like Ecoflex) are truly waterproof?

The question of solar panels is intriguing. I would be interested to know if they are a DIY project, or do they have to be bought? It seems that the Garn would be perfect to store heated water from solar panels during the summer for domestic use, rather than having to light a fire.

 

[Nofossil]

Well, in spite of an inch or two of snow in the night, which was unexpected, we got the footer poured today for the Garn room. Next item on the list will be to put in a pair of 1 1/2" PEX lines and insulate the same to carry the hot water from the Garn to the current boiler loop. Does anyone know if the already insulated lines available (like Ecoflex) are truly waterproof?

The question of solar panels is intriguing. I would be interested to know if they are a DIY project, or do they have to be bought? It seems that the Garn would be perfect to store heated water from solar panels during the summer for domestic use, rather than having to light a fire.

I've done some experimenting with solar heat and hot water storage. It can be a DIY project, especially for people who aren't afraid of projects. I think you qualify. I've got some details on my site - link is in my signature below.

 

[Father John]

Nofossil, how are your commercial glazed copper panels made? That is the part I was wondering about being DIY. Is it a copper loop sandwiched between layers of glass and sealed, like a thermal pane window?

The Garn is going to be backed up to the south wall of the boiler room, with its fire chamber door facing north. Can I use the exterior face of that south wall to mount a large panel? Will it thermosiphon and circulate back into the Garn tank?

 

[Nofossil]

Nofossil, how are your commercial glazed copper panels made? That is the part I was wondering about being DIY. Is it a copper loop sandwiched between layers of glass and sealed, like a thermal pane window?

The Garn is going to be backed up to the south wall of the boiler room, with its fire chamber door facing north. Can I use the exterior face of that south wall to mount a large panel? Will it thermosiphon and circulate back into the Garn tank?

They're not that impressive in terms of construction or complexity, except for the collector surface itself.

The glass is single pane tempered glass, and based on my experience double pane would not be necessary. The box is made of light gauge aluminum with aluminum extrusions to provide a little rigidity and a place for screws to grab on to. There's about 2" of fiberglass insulation behind the collector surface, and a little around the sides of the box.

The collector surface is a copper sheet with several small tubes formed into it. There's a 1/2" header at each end that the tubes are brazed into. Given the price of copper, I'd explore other alternatives - perhaps aluminum tubing and aluminum sheet. You'd have to find someone who can weld fittings onto it, but it would be vastly cheaper than copper and just as effective. It would take some thought and perhaps experimentation to find the best way to thermally couple the tubing and the sheet.

Temperatures in the collector box reach 225 or so if water flow is stopped, so material selection takes some thought. Plastic fittings are a bad idea. I think metal panels with an external wooden frame would work.

The best situation is to have the top of the panels below the storage tank. In that case, you don't need any pumps or controls at all - thermosiphoning is your friend. If the panel and tank overlap, thermosiphoning can still work, but it's a bit more dicey. You have to get an ultra low backpressure check valve to prevent reverse thermosiphoning from cooling off your storage at night. The higher the panels are relative to the storage, the less effective thermosiphoning is.

You can use a thermostatically controlled pump if you have to.

I use mine only in the warmer months, so I don't need antifreeze. In your situation, you might build a simple shell-and-tube HX (like the sidearm) to keep the boiler water and the solar panel fluid separate.

Good luck with this project. I'm very impressed with everything you've done so far.

 

[Eric Johnson]

When I was in Guadalajara Mexico a few years back, my dad was volunteering at an orphanage that had huge solar collectors on the roof--all ruined in a freak freeze some years earlier. He was trying to rehab them so that the orphanage could have some free hot water again. The design was one that I decided to use on my in-tank heat exchanger, which I hope to have running this weekend. Basically, if you took the header assembly pictured below and sandwiched it between two sheets of corrugated steel roofing painted black, you'd be pretty close to the elements on those solar heaters, which I think worked pretty well when they worked. They operated mostly through convection, though I believe there was a pump and a storage tank involved.

I think the trend, which I would endorse, is to buy manufactured collectors, most of which tend to be evacuated tube designs, and DIY the rest of the setup. The panels are around $800 each, and I'm told and evac. tubes are capable of extracting a remarkable amount of heat even on cloudy days. I suspect that you're in prime solar country in southern VA. And they're a perfect compliment to a wood gasification system seup, I think. Of course, free wood is cheaper than solar panels, so it may not be an issue. But if you are concerned about carbon emissions, then it's hard to discount solar.

 

[Father John]

Where do you find these evacuated tube collectors for sale? It is a pity copper is so expensive, since I really haven't the skill or ability to deal with aluminum. I could find someone who can, but then I don't know what that would cost.

We would be interested in an eventual solar component to our setup, not because we risk ever running out of wood, but because anything that makes our time and labor go further may be well justified. We try to grow our own food, and in general provide for most of our daily needs from this property, so a one-time project like solar collectors would be worthwhile if there was a recurrent savings in work for the future.

Although I can picture nofossil's collector box, I am not sure what the collector surface looks like. How are the tubes formed into the sheet? I am imagining they are a similar layout to Eric's assembly (that's a fine piece of work by the way), overlaying the sheet, but I am not sure that is correct.

To get below the Garn storage tank much would require laying the collector nearly flat on the ground, which would presumably lower it by only so much as the Garn is tall. Perhaps this would be enough.

 

[Nofossil]

Where do you find these evacuated tube collectors for sale? It is a pity copper is so expensive, since I really haven't the skill or ability to deal with aluminum. I could find someone who can, but then I don't know what that would cost.

We would be interested in an eventual solar component to our setup, not because we risk ever running out of wood, but because anything that makes our time and labor go further may be well justified. We try to grow our own food, and in general provide for most of our daily needs from this property, so a one-time project like solar collectors would be worthwhile if there was a recurrent savings in work for the future.

Although I can picture nofossil's collector box, I am not sure what the collector surface looks like. How are the tubes formed into the sheet? I am imagining they are a similar layout to Eric's assembly (that's a fine piece of work by the way), overlaying the sheet, but I am not sure that is correct.

To get below the Garn storage tank much would require laying the collector nearly flat on the ground, which would presumably lower it by only so much as the Garn is tall. Perhaps this would be enough.

I've experimented with a very inexpensive collector surface - a solar swimming pool heater. It's 4' x 20', and made of extruded plastic. Just lying on the ground in Vermont, it supplies water at 130 degrees. With a simple glazed enclosure, you could probably do much better, though at some point it might get too hot and degrade the plastic. I've got pictures here.

Nearly flat on the ground is fine for summer sun. You'd want a little angle to flush bubbles out, but you don't need much.

 

[brad068]

I'm hoping to hook up my solar hot water system into my homemade garn boiler. I removed a complete system from a home that a young new couple bought. It has 4, 4'x10' panels that are about 200lbs each. I got the trellis frame the two piece fiberglass storage tank, 4 circulators, 3 finned copper tube hx, a high eff. electric water heater (maybe backup), and the control box. The name on the control box is Independent Energy Inc. East Greenwich, R.I. C-100 system manager. I was wondering what the initial cost of this system was and how old it is. The expansion tank had a code on it ending in 81 I think.

My goal is to plumb this into my garn tank and hopefully generate enough heat to carry me through the summer to heat my DHW and maybe prolong firings in the heating season. My concern is how much heat will the panels generate in terms of temp range.

 

[Nofossil]

I'm hoping to hook up my solar hot water system into my homemade garn boiler. I removed a complete system from a home that a young new couple bought. It has 4, 4'x10' panels that are about 200lbs each. I got the trellis frame the two piece fiberglass storage tank, 4 circulators, 3 finned copper tube hx, a high eff. electric water heater (maybe backup), and the control box. The name on the control box is Independent Energy Inc. East Greenwich, R.I. C-100 system manager. I was wondering what the initial cost of this system was and how old it is. The expansion tank had a code on it ending in 81 I think.

My goal is to plumb this into my garn tank and hopefully generate enough heat to carry me through the summer to heat my DHW and maybe prolong firings in the heating season. My concern is how much heat will the panels generate in terms of temp range.

You should get more than enough heat - more than you'll be able to store, so you'll have to think about dumping excess heat. I've boiled water in my panels when flow got blocked. My system routinely produced 175 degree water. You'll also want a tempering valve so that you don't get scalding water at the tap.

 

[Nofossil]

Where do you find these evacuated tube collectors for sale? It is a pity copper is so expensive, since I really haven't the skill or ability to deal with aluminum. I could find someone who can, but then I don't know what that would cost.

We would be interested in an eventual solar component to our setup, not because we risk ever running out of wood, but because anything that makes our time and labor go further may be well justified. We try to grow our own food, and in general provide for most of our daily needs from this property, so a one-time project like solar collectors would be worthwhile if there was a recurrent savings in work for the future.

Although I can picture nofossil's collector box, I am not sure what the collector surface looks like. How are the tubes formed into the sheet? I am imagining they are a similar layout to Eric's assembly (that's a fine piece of work by the way), overlaying the sheet, but I am not sure that is correct.

To get below the Garn storage tank much would require laying the collector nearly flat on the ground, which would presumably lower it by only so much as the Garn is tall. Perhaps this would be enough.

Another comment on solar panels and themosiphoning:

If your hot water needs are anywhere near as modest as your heating needs, it may be worthwhile thinking about another approach. Could you install a hot water tank adjacent to but higher than the Garn? It could then be heated from the Garn via convection, and it would give you more leeway on solar panel positioning. A smaller tank will also give you usable hot water much more quickly and more often, and could have its own backup heat source.

For instance, a 120 gallon hot water tank heated to 120 degrees is much more useful than a 2000 gallon tank heated to 95 degrees. If that smaller tank were heated with oil, electricity, or propane as a backup heat source, then you'd have hot water all the time while taking advantage of each heat source automatically.

 

[Eric Johnson]

Here's just one online source for evacuated solar panels that includes pricing. I think if you're serious about solar, you should begin a thread in the Green Room forum. There are a couple of people who hang around there who have quite a bit of experience with solar and some pretty good ideas. Not that I disagree with anything nofossil has said (so far). If you have a gasification boiler, it seems to me, solar is less of a practical decision and more of a philosophical commitment to alternative energy, if that makes sense. In my case, it would be one more thing to play with.

(broken link removed to http://www.siliconsolar.com/Evacuated-Tube-Solar-Collectors-p-16145.html)

BTW, my parents recently bought a house in a city near their tree farm so that they can spend the harshest part of the Wisconsin winters in civilized surroundings. The house has a couple of huge solar collectors on the roof, and my dad reports that on cold, sunny days (i.e., below freezing) the house stays at 70 degrees without any help from the furnace. Imagine the impact on the energy/pollution equation if every house had a system like that.

 

[Father John]

Since this solar project will probably remain an experiment for a while, nofossil's pool heater appeals to me as an inexpensive way to begin trying things out. After the boiler room is built I will see about setting up one of those just outside the building.

Meanwhile, is there a consensus on the best way to insulate the PEX lines between an outdoor boiler room and the house? Or does everyone buy the pre-insulated corrugated product?

Merry Christmas to all.

 

[Eric Johnson]

There are many ways to do it, ranging from total DIY arrangements to turn-key systems ready to drop into the ground. My piping all runs through building space, so I don't have any experience with buried pipe.

You might want to start a new thread with a descriptive title and see who drops in.

 

[Tony H]

Father John - Nice looking project! The pre-insulated corrugated stuff looked a little questionable to me so I used a product called Logstor you can see some info about it at Cozyheat.net. On the other hand I am in northern Illinois where the ground is frozen much deeper than your location so it may not be worth the additional costs.

 

[Father John]

Thanks for the info and name of Logstor. Even though our climate is milder, we have the same risk of getting moisture in the lines, ruining the insulation. If I can't find a product like Logstor we can afford, I may have to insulate my own lines and install inside some of the PVC we have leftover from our project.

 

[Father John]

A couple of days ago I got the first couple of block courses laid, and was able to rake out the gravel for the slab in the new Garn boiler room. I had to spend an inordinate amount of time moving our generator, tearing up the concrete pad, and rerouting all the conduits, but it was necessary to make sure the floor in the boiler room is all the same level.

Today I worked on building the leads and corners, and hope to get many more block laid tomorrow. Since I will be using 1 1/2" Pex, which I think will be too stiff to bend up and keep near the inside wall, I am making a well in the floor, at the end of the trench, so I can always get to the Pex fittings.

When the Pex arrives next week the fun of threading it through the carrier pipe can begin.

 

[Eric Johnson]

I found pex-al-pex, which is stiff like soft copper, to be a lot easier to work with than I expected. You can't make tight turns without expensive fittings, but it will snake where you want it to go and it's easy to pull long distances.

 

[Tony H]

The standard required bending rate of normal pex is 6 times the outside diameter (nominal size plus +1/8") of the tubing. So if you figure 7 times you should be safe. For example 1' pipe equals 6 3/4 Radii on the actual chart. There are some brands that claim better rates but this is the standard all are supposed to meet.

A couple of thoughts when pulling pipe thru another pipe gained from 20 years of trial and error.

Pull all inner pipes together that reside in a single tube and pull all like sizes if possible.

If you need some AC or controll wires pull them in a seperate tube. The black plastic "utility" pipe sold at most lumber yards works well for this as long as it's allowed by local code. (Well even if not allowed it still works well)

Pulling lube is your pal !
Sold in the electrical section use lots of it if you have a number of bends in your run and just because it seems ok to start with does not mean you won't wish you had put more lube on that first 50 feet when you hit those bends 100' later.

For the larger pex pipe and or longer runs consider using a pulling sleeve or whip This is a wire mesh sleeve several inches long open on one end to insert the pipe and connected to a stranded cable loop on the other end to connect your pull rope as you pull the mesh tightens down on the cable or pipe so you can pull with alot of force like a come-a-long or a truck and have a secure connection that slides easily thru the pipe.

It's a good idea to leave a well even if you don't need any connections there you might need a pull point or "hand hole" to assist the pipe thru that area.

 

[Father John]

It has been taking me a good while to get the block walls laid for the new Garn room, especially since the weather has been back and forth this last month. It is hard to get a good solid week of outside work in this time of year. Still, there are just three block courses left to go before I can pour the bond beam and frame the roof.

At the same time I took advantage of a comfortable day last week to insulate the 1 1/2" Rehau pex lines to connect the Garn to the current boiler loop. I used Imcolock insulation with a 1" thick wall, kindly provided by our friends at Nomaco. Since I was working alone I had to come up with a way to control the 100 ft long lines so I could slip the black corrugated carrier pipe over them. I accomplished this by taping one end of the insulated pex to a fence post, then I attached the pull rope (which I previously had slipped through the corrugated pipe with a fish tape) to the other end of the pex. Then I tied the free end of the rope to a tree after pulling tight. The corrugated pipe easily slipped down the taut rope and over the pex. The assembly was then dropped into the trench and shoved through the holes in the walls at each end.

The Garn is due to arrive any day this week, so I really better hurry with the block.