# Gasification quandry



## rvtgr8 (Jan 8, 2008)

My wife and I have built two homes on our sixty acre ranch near Elbert, Colorado on the Palmer Divide.  We built in a wooded area and so we have unlimited supplies of downed timber for firewood.  Our first home (now our guest quarters) was a hybrid straw bale design.  It is small and takes almost nothing to heat it.  Our small Lopi wood stove could run you out on the coldest of days.  We built our second home completely of surplus materials.  It is well insulated (8" cellulose filled walls with two layers of 5/8" osb sheathing, red cedar siding and a wainscot of natural stone.  It has a concrete tile roof.  It is framed in steel.  We put radiant heat in the floor.  We have a propane Burnham boiler with a side arm that heats our hot water.  We want to add a gasification boiler in the garage.  Being on a fixed income, skyrocketing propane costs are taking a bite out of the budget.  Gasification seems a logical choice for us.  With that introduction in mind, I have several rather complex questions:

1. I am currently heating 2,500 s.f. and I would like to eventually consider adding an arm to our 1,000 s.f. green house.  We average $100 per month on propane now with the 136,000 btu Burnham.  Should I go for a larger gasification boiler in terms of btu's?
2. I am down to either an EKO or Biomax out of W.V. and I have had some interest in a Greenwood.  I was a bit discouraged about troubles expressed in this forum over the cracking in the masonry lining of the Greenwood.  Is one of these units substantively better than the other?  Since I will be doing most of the plumbing myself, is one of these brands more complicated (in terms of installation) than the others?
3. I am going to frame in a boiler room in my attached garage.  Can clearance distances be safely reduced by lining the boiler room with cinder block? Also, fresh air is an obvious consideration in a boiler room.  Is it feasible to force air into the BR based on the burn requirements?  This question will obviously prove that while I will try to build anything under the sun, actually knowing what I am doing does not get in my way;-) .
4.  Should wood storage be outside of the BR?

I am including a picture of our home.  My wife and I did all of the work ourselves and it is something of which we are very proud.  Now if we can just heat it with a gasification boiler, we might finally be able to get on with retirement dreams.

Robert


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## Eric Johnson (Jan 8, 2008)

Welcome to the Boiler Room, Robert. Nice looking place you've got there. Sounds like you're the kind of guy who will appreciate a gasifier.

I have the EKO 60, which I got from Cozy Heat (upper banner), and it was not difficult to install. Like you, my lack of experience and knowledge doesn't stop me from forging ahead when I think I can do something. We also have a couple of BioMax owners here, and I guess you're familiar with the Greenwood guys.

I have my boiler in a small cinderblock room in my barn. I also stack a winter's worth of wood around the boiler room, so everything is in one place, under one roof, and ready for just about anything. I don't have answers to all your questions, but the following two pics ought to help. I built the room for my previous boiler, which I pulled out to make room for the EKO. It's a tight squeeze, but everything fit, and it works like a charm. My combustion air comes in from the outside through a vent in the wall.


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## jebatty (Jan 8, 2008)

You and your wife are to be commended on your ingenuity and creativity. My wife and I have heated our 50-yr old 1500 sq ft home in northern mn for 20 years with a free standing wood stove in a corner of our living area. Last Sept I self-installed a Tarm Solo Plus 40 (140,000 btu) gassification boiler in my wood-working shop, an old converted barn, 800 sq ft, 10 ft ceiling, and very poorly insulated. I am impressed with the Tarm and you also might want to look at the Tarm. Tarm makes both larger and smaller boilers.

"Should I go for a larger gasification boiler in terms of btu’s?" You should consider substantial water storage for the boiler to achieve long, efficient burn times, and so that the boiler does not need to fire/re-fire every time you have a need for heat. With water storage larger is almost always better than smaller. Others may have more info, but since I am thinking of moving from 800 to 1200 gallons for my shop, I would think you should consider at least this amount if not more. With storage, you might be able to actually reduce your boiler size from what would be required for a conventional boiler. For example, it takes about 10 hours of burn time to bring 800 gallons of water from 80F to 150F, and then I draw heat from the storage which lasts 1 - 3 days (boiler off) with outside temps ranging between 10-25 on the low side and 25-40 on the high side. Obviously we have much colder temps where I live, but these are not consistent for extended periods.

"Since I will be doing most of the plumbing myself, is one of these brands more complicated (in terms of installation) than the others?" I have no experience on this, since I only installed a Tarm, but I used as a guide the plumbing for a traditional LP boiler. Three key differences for me: 1) a boiler self-feed loop with a thermostatic mixing valve to better insure hot water always returning to the boiler. Wood gassification boilers operate much more efficiently if they are not fed with cold water on the return during operation. 2) using a plate heat exchanger plumbed into a short boiler loop to isolate the boiler from the heat side (also useful for DHW). This is not "needed," but I wanted to use antifreeze in the boiler and water for the heat loops. There are times when I may shut my boiler down for an extended time in the winter, and I wanted to take no chance of freeze-up. 3) boiler controls likely will differ, depending on make of boiler.

"I am going to frame in a boiler room in my attached garage.  Can clearance distances be safely reduced by lining the boiler room with cinder block? Also, fresh air is an obvious consideration in a boiler room.  Is it feasible to force air into the BR based on the burn requirements?" I think the answer to both is yes. Clearances for my boiler are the same as for a free-standing wood stove without heat shields, and actually side clearances could be reduced. 36" for the stack plus room for front loading are needed. I don't think my boiler draws anymore air than a wood stove, so air requirements are not huge, but fresh air is needed.

"Should wood storage be outside of the BR?" Lots of ways to go here. In general, I always burn 3rd year wood (dried two full seasons, burn following winter). I cut, stack and have well-ventilated, covered wood sheds for the wood. I burn almost only pine slab wood, and one wheelbarrow load covers 2-3 loadings of the stove. I prefer outside wood storage because of insects and pests, but a smaller quantity stored in the BR for convenience minimizes these problems.

Yours is the kind of house and living arrangement I would love to see sometime. Good luck.


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## Nofossil (Jan 8, 2008)

I'll echo the previous post - good advice.

After a lot of head scratching, I went for the smallest boiler I could find - the EKO 25, which is rated for 80,000 BTU/hr. I'm heating a reasonably well insulated 3500 square foot house in Vermont as well as DHW and a hot tub. My peak space heating load is around 30,000 BTU/hr, so the boiler has more than enough capacity. I have 880 gallons of storage, and I can skip days if it's not too cold. Also, the house temp stays constant between fires. When I burn, I burn flat out for best efficiency.

I have a writeup on my system with diagrams and data on my site - link is in my signature below.

Good luck - I'm envious.


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## rvtgr8 (Jan 9, 2008)

Hey All,

Thanks for responding to me and giving me answers on my questions.  This site is pretty remarkable.  Not only are people knowledgeable about this heating technology, they are quick to share said information with the the the most novice among them.    

I am now beginning to explore the concept of using hot water storage.  The arguments for their use is somewhat compelling.  The problem becomes space.  I have been looking at the Garn, just because it combines both the boiler and water storage which I believe might make for a smaller overall footprint.  Unfortunately, the Garn site was not helpful from a couple of angles.  First, how much does one of these bad boys cost?  Can't be cheap!  Second, what are the standard sizes of this thing?

Robert


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## Eric Johnson (Jan 9, 2008)

Garn is not known, at least not on this site, for prompt responses to sales inquiries. But the Garn is, by all accounts, an excellent choice in some circumstances.

There are a couple of things to bear in mind:

1.) The Garn is nonpressurized, so if you want to mate it to your existing hydronic system, you'll either have to convert your current setup to a nonpressurized state, or use a heat exchanger. I think the latter approach makes the most sense, but one of our members, Father John, said the factory strongly recommended the former. But it doesn't make sense to me.

2.) Most of us have learned the hard way that by the time you're done screwing around with storage and intank heat exchangers, you'll probably spend as much (or more than) the difference between the cost of the smallest Garn and a typical Euro-style gasifier, such as the EKO, Tarm or Econoburn with comparable storage. Not included in that calculation, however, is the cost of building or adapting enough space to house the Garn and associated insulation, etc.

3.) Even the smallest Garn is a lot bigger than most residential consumers would usually consider, on a btu/hour basis. But people like TCaldwell (another member) don't seem to have problems with that.

4.) Another one of our members, heaterman, is a Garn dealer, I believe. A friend of mine in Wisconsin Clyde Samsel at samsel@uniontel.net, is another. They might be able to answer specific questions, or give you the red-phone hotline connection to the Garn sales dept.

One nice thing about detatched hot water storage is that it can be located hundreds of feet away from the boiler itself, which can be a good thing. Of course, the flip side of that record is that you're going to have higher transmission losses, and possibly higher standby losses, depending on how good your insulation strategy is. Another good thing about remote storage is that you can bypass it when you want to. With large-capacity onboard storage like a Garn, you're in for a long wait if you have a cold house and a cold boiler. On the other hand (sound familiar?) once you get the Garn momentum on your side, you've got a lot of cushion to play with.


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## jebatty (Jan 9, 2008)

This comment is very well taken: "Another good thing about remote storage is that you can bypass it when you want to. With large-capacity onboard storage like a Garn, you’re in for a long wait if you have a cold house and a cold boiler." I have a unit heater loop which by twist of a valve will be fed by the boiler directly for instant, full heat. Another twist and all heat moves to storage, or twist in-between for some to unit heater and some directly to storage.


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## Tony H (Jan 9, 2008)

Great looking place you have there! Great advice as usual!
A couple of thoughts on the garage BR 
The clearances for the boiler are from flammable materials so you can go much lower with cinder block just make sure you have room to connect everything and service everything without a problem and of course check the local building codes.
Consider a door to the outside for loading in firewood.
Way in the past I used some vents that were controlled with 120vac so if you check around you can probably find something similar and use the boiler controller plus maybe a relay to open it during system burn time.


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## rvtgr8 (Jan 9, 2008)

Eric,
Thanks for the quick return.  I was unaware that it was not a pressurized system and that fact essentially eliminates the Garn from my thinking.  How about the Tarm 60 with their water storage system?  Are they fairly reliable.  They do have an outlet in Northern Colorado.

Robert


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## Eric Johnson (Jan 9, 2008)

The Tarm is an excellent gasifier. Basically, the Tarm, EKO and Econoburn (bottom banner) are similar in design and performance, from what I can gather. I seriously considered the Tarm Solo 60, but its max wood length is 20 inches, and all my wood (some 40 full cords) is 24 inches.

A couple more points.....

It's against code to put a wood-fired appliance in an attached garage.

I have about an inch of clearance on either side of my boiler from the cinder block walls, which are filled with vermiculite. On the EKO, all of the regular maintenance/service points are front, back and top. Since I have doors on both ends, access is easy and complete. If I ever had to take the side panels off, however, I'd have to disconnect the piping and pull it back out of there.


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## jebatty (Jan 9, 2008)

Ditto on Tarm -- top, back and front -- Tarm is pressurized. I do use a HX for non-pressurized storage. But need room somewhere for electrical boxes, etc. Obviously much latitude here, but I put electrical boxes on the side because this was convenient in my case. On wood length, 20" for Tarm is true, and I had a fair quantity of wood at 24". Fortunately, I had a pile of logs not yet cut, so making the shift to 20" was not a big deal. I did recut the 24 to 20 and had a lot of small pieces for early season burns.


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## Eric Johnson (Jan 9, 2008)

Yeah, the pressurized/nonpressurized thing becomes kind of a nonissue when you're talking about storage, unless you decide to go with pressurized storage (usually 500- or 1000-gallon LP gas tanks). Otherwise, you're dealing with some sort of heat exchanger at some point anyway. One thing about all that onboard storage with the Garn, however, is that you have to treat the water, and there's a lot of it. With a rubber-lined nonpressurized tank, steel corrosion and boiler integrity in an oxygenated environment is not an issue like it is with an open system like the Garn.


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## chrisfallis (Jan 9, 2008)

I installed a Tarm unti in my basement in 1997 and regretted that I did not have a bunch of hot water storage.  There was a lot of user error involved, like stuffing the firebox full of wod on spring and fall days when there was little call for heat.  I had a number of instances where the chimney was almost completely blocked by creosote.  I also had a large number of cast iron radiators and 5 or 6 inch pipe which contained probably a couple hundred gallons of water.  Some morings I would be feeding the fire and hear the circulator pump kick on.  All that cool water from upstairs would rush into the boiler and I'd watch the boiler temps go from 180 degrees to about 80 in a matter of 30 seconds.  It would be just about this time when we also needed hot water for showers.  The spousal acceptance factor for the question "Wadda ya want? Heat or hot water?" was pretty low.  We had a natural gas backup in the Tarm, and it would bravely try to add its 100K or less BTU to the water, but it would take hours and hours to warm up our cold house.  A big storage tank would have eliminated the smokey standby mode and may have added to my wife's quality of life.  We sold the house 4 years later and the new owners switched back to natural gas heat.

Did I mention the fine coat of gray ash all over the basement?  And I was humping in garbage can loads of wood from outside and down the stairs on a daily basis.  This made me swear to move any future woodburner outside. 

I had the pleasure of meeting a Garn dealer in Santa Fe, NM this past October.  He showed me a demonstartion unit that was installed outside a local community college.  The boiler hadn't been run for a few days so he back fed it from the school's main boiler until it reached 110 degrees.  Evidently cold starting these beasts can cause condensation and damage issues,  Garn's recommendation is that you warm it up with another boiler or install electric hot water heater elements to keep the temps above the critical level.  LThe boiler was insatlled in one half of a shipping container, the other half of the container used for wood storage.  My wife immediately niixed the idea of a shipping container in our backyard, but the idea has some other applications.  Lighting the unit consisted of tossing a some inch or two diameter sticksin the firebox with a peice of lit newspaper.  A few minutes later bigger split logs were added.  Since this was a demonstration unit, it was ticked out with recording gear to show heat output.  The dealer said that he had no problem extracting the rated BTU output of the boiler, and it was possible, with diligent monitoring, to even surpass it by 10%.    There was a bit of smoke roll out when loading, in spite of the iinduced draft fan.  Aother reason to keep this outside the living space.

I would like to buy one of these and install it in my detached garage.  I still have to quantify my haeting demads, but on cold winter days I use about 1,000,000 BTU per day equivalent of natural gas into a circa 1900 boiler and circa 1940 hot air furnace.  I probably am getting 50% efficeincy with these old units, so maybe the heat load is not as ugly as it seems.  I think it would be neat to fire a wood boiler like hot holy hell for a few hours and get 1 to 1.5M BTU of heat into storage.  I'll take marginal  standby losses over constant smoke any day.


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## Eric Johnson (Jan 9, 2008)

Welcome to the Boiler Room, Chris.

Was your Tarm a gasification boiler, or one of the company's standard wood-fired boilers?

The Wife Approval Factor (WAF) heavily influences most of the calculations made around here.

If you had hung a $100 sidearm heat exchanger on your hot water heater, you would have had plenty of hot water, regardless of the state of the boiler.

Glad to have you aboard. Hopefully we can share some ideas and make your second attempt at central hydronic wood heat a more positive one.


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## ISeeDeadBTUs (Jan 9, 2008)

I'm just jealous of Chris' snow. Is it supposed to be 60 In January in NY???


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## chrisfallis (Jan 9, 2008)

The Tarm was a gasification model, and would burn very cleanly as long as it was burning.  On idle, though, the firebox and chimney would end up coated with creosote.  I suspect that smoke was slipping past the bypass (or loading) damper and hitting a relatively cool chimney (all insulated and all inside the center of the house).  We also had to watch for blowback or spontaneous ignition of a firebox full of gas.  The owners' manual said to open the bypass damper use the fan to clear the firebox before opening the door in front.  Sometimes I forgot and could see the hot coals and rolling clouds of pyrolysis gases when I opened the door.  All that was missing was oxygen, which Ihad just introduced.  Only quick reflexes kept me from getting facial burns, although a friend lost his eyebrows when he didn't move quickly enough.  I usually just slammed the door closed and was rewarded with a whoosh and a puff that made my heart skip a beat or two.

My DHW setup consisted of a coil inside the boiler and my decommissioned gas water heater acting as a storage tank.  There was a circulating pump between the boiler and the tank to keep the storage tank temperatures up.  If the storage tank temp was low, it would try to draw heat from the boiler coil.  If there was no fire (cold night, out of fuel, stupid fire builder) the "hot water" and the boiler could be ambient temperature.  I always got up early in the morning, shut off the circulator pump for the radiators, and let the boiler heat up our supply of hot water.  15 minutes or so would be plenty of time.  If Momma didn't have hot water for a shower on a winter morning, weren't nobody happy.  After showers, I would turn the main circulator on a let the radiators upstairs have a little heat.  The house would take a few hours, but would eventually heat up.

I did get a bit tired of the small firebox and the every other hour tending during the winter.  OK, maybe I am a bit crazy about the whole wood haeting thing, but I really wanted to sqqeak every possible BTU from the boiler.  I think with a bigger firebox and more capacity for heat storage this system would have been more than adequate.


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## Eric Johnson (Jan 9, 2008)

I hear you on momma's hot shower. For me, that's usually Priority One.

I do know that ten years is a long time, and I assume that Tarm and other manufacturers have made significant improvement in gasifier technology since then--especially in the area of idling.

I'm a little confused on your hot water problem. Usually a check valve or flow control valve is all that is needed to keep the hot water in the tank, once it gets in there. And you should have an aquastat hooked up to your pump so that it stops pumping water through the coil as soon as the boiler gets below, say, 140 degrees. Both are cheap and easy to do. As it is, with no storage, I get up to a cold boiler most mornings, and a 50-gallon tank full of hot water. So it's not hard to do (if I can do it, anyone can).

I have an EKO 60, which is very similar in design the Tarm gasifiers, and I don't get any creosote during idle, though I try to idle it as little as possible. I suspect a Tarm Solo 60 is similar, though some people seem to have more trouble with idling than others--with both brands. Here's what I'm heating with a 60kw boiler and around 10 cords of dry hardwood per year.


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## Reggie Dunlap (Jan 9, 2008)

It sounds like something wasn't right if you were getting that much creosote. I checked my chimney today after 3 weeks burning and there was some fly ash but no creoste. You may be right that the bypass damper wasn't fully closed, that would do it.


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## TCaldwell (Jan 10, 2008)

rvtgr8,  can i ask why a non pressure boiler is something you want to stay away from? thanks tom


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## jebatty (Jan 10, 2008)

Slow heating, whether Tarm or another gassification boiler, seems principally related to four things: 1) having considerable storage which has fully cooled and feeding the system from storage, 2) having a very large system which has fully cooled (effectively storage), 3) not having a mixing load valve on the boiler, or 4) not having a boiler bypass direct to heating rather than to storage.

I have 800 gallons of non-pressurized water heated through a plate hx; a small system; a mixing loading valve; and bypass to system. I did a self-install, challenging but clearly doable.

My Tarm Solo Plus 40 moves from boiler temp of, say 50, to 150 in about 1/2 hour from a cold start. At 150 my circ pump kicks in. If immediate heat needed, open the bypass valve and 150+ water immediately is into the heating system. As immediate heat not needed, partially close down the bypass, then fully closed, then heat from storage. O do not have DHW installed yet.

It takes about 5 minutes to start a roaring fire with dry kindling and few tied knots of newspaper (top down): firebox closed, damper open, draft fan on, gassification door open. Then shut off fan, open bypass, open firebox, add about 4-5 small splits -- no smoke into room at all. Shut firebox, turn on fan, close gassification door, close damper, let burn for a couple more minutes. Flue temp now at least 300 and climbing. Shut off fan, open damper, open firebox, fully load -- no smoke in room. Close firebox, turn on fan, close damper, enjoy 100% burn until fire burns out -- my hx will draw to storage all the heat the Tarm can produce. A load of pine will last about 3-5 hours, depending on whether it is a first burn or a reload. Rarely will the Tarm reach 190 and shut off and cycle, but if it does, the off time is about 15 minutes. It will almost always hover around 170-180. Thus, no idling. This is the great benefit of sufficient storage with a hx of sufficient capacity. BTW, once the circ pump kicks on, it stays on. This is the benefit of the mixing load valve. The boiler never cools down because of cold return water, the boiler only continues to heat and stays hot until the fire burns out.

It's now 4 months of heating this winter. I burn pine slab wood, full of sap and pitch, but dry (10-15%). Chimney is 4' black stove pipe to ceiling and 18' of stainless, insulated, 6" pipe, through an unheated attic. Top of chimney is 3-4 feet above the roof peak, excellent draft. There is only a fine coating of dust and discoloration on the stainless chimney. No creosote at all. I have not cleaned it. The black stove pipe I have brushed twice but probably would not have needed to do this. A very light layer of ash has accumulated in the black stove pipe.

I found it hard to believe the small quantity of ash produced. 10-12 hours of burning pine will produce about 1-1/2 cups of ash.

Once my storage is up to at least 150, I usually only have to load and fire the boiler once per day. Sometimes a second load is needed if it is really cold, and I try to do this while low coals remain so the fire starts right up. Actually, at this point the refractory remains quite hot, and a burn to gassification is fast.

For a wood burning appliance for the home, I can hardly imagine anything sweeter, easier, cleaner, or smoke free, both inside and outside.

I am certain others with different brands have had similar experiences. Hope this help others who still are learning how  to operate their systems, or has a pointer for more experienced users. Send your pointers my way!


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## Eric Johnson (Jan 10, 2008)

You'll have to give us some details of your flat plate hx for charging the tank, Jim. I was planning to do that, but went with a two-part in-tank copper hx instead, but have yet to get it all hooked up. But I am interested in how you engineered it (sorry if you've already explained it in anther post that I missed), since I gave the issue a lot of thought.

Other than that, your experience with the Solo 40 sounds a lot like mine. Like you, I get zero creosote, good gasification quickly and a clean burn in all but early-stage idle. I still can't believe the amount of heat the thing puts out with a small amount of wood, compared to my old Royall conventional indoor boiler.

I've noticed that there are a couple of threshholds with the coal bed. With a good bed of coals, i.e., covering the nozzles, you can just toss a load of wood in and keep right on trucking. With a meager bed of coals, it pays to open the ash door and get a good fire going again before closing the bypass damper and initiating gasification. But all you need to load in is wood. With just a few coals, you need to put in some paper, pine cones, bark, whatever and open the ash door, or you're in for a long wait. I guess I've learned that a gasification nozzle is not a cast iron grate, so it's not as responsive with just a few coals. But I will say that grate or no grate, this is the easiest boiler I've owned to start up from a cold start.

One thing I think I've learned is that everyone's air needs are different. These boilers have factory settings, but you have to adjust them to fit your situation. My boiler smoked some of the time with the factory settings, but since I've opened them up (the secondaries), nothing comes out the stack except white vapor when it's below zero.


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## TCaldwell (Jan 10, 2008)

jebatty, with the garn  I daily raise 2,510 gal of water 45+deg  representing 940,860btu in under 2.5 hrs, with a partial reload of wood at the 1 hr mark!


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## Hbbyloggr (Jan 10, 2008)

You might also take a look at Emprye. They have an outdoor stand alone gasifier new on the market. We run an Empyre 450 OWB and have had good luck with the quality of construction.

Hbbyloggr


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## Hbbyloggr (Jan 10, 2008)

This is the link to the Empyre ECB.         http://www.profab.org/ 

Hbbyloggr


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## rvtgr8 (Jan 10, 2008)

TC,
Perhaps my ignorance is showing, but I was under the impression that it was a somewhat more complicated to use an unpressurized boiler on a pressurerized radiant system such as mine.  I know it is not impossible, but I only have a purple belt in plumbing.  To further torture this lame analogy, I have found myself in a plumbing dojo filled with blackbelts who actually possess working knowledge of engineering marvels that sport names like Tarm, Garn, Eko, BioMax and the Polish Sausage.  I think that last one may not be a gasification unit.  I obviously need to do more research.  Honestly, the only Garn I had heard of before last November was an alien  beast fought by Captain James T. Kirk on the original Star Trek.  That is why I am here.  I seek enlightenment from the masters.  I welcome any and all advice.  Am I mistaken about the pressure issue?


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## jebatty (Jan 10, 2008)

The remarkable successes with the gassification boilers are numerous and adequate testimony to the tremendous advances in technology in this area.

"You’ll have to give us some details of your flat plate hx for charging the tank, Jim." Mine may be a little unique, but I think the concepts should be transferable to other areas. My installation is inside my wood-working shop, including boiler and steel storage tank. All heat, except for that which goes up the stack, stays inside.

Think of the hx as a single heating zone or heat load. The boiler simply has a short circular loop to the hx and return. This is pressurized, with expansion tank, air scooper and vent. I use the Tarm recommended Termovar load mixing valve, so really no hot water moves to the hx until the Termovar starts to open.

On the return side, or outlet side, of the Termovar, I have a surface mounted line-voltage aquastat set at 150. Until this aquastat closes, water is moving by gravity feed from the boiler supply, through the Termovar, and return to boiler. No water is moving through the hx. As soon as temp hits 150, the aquastat closes and turns on the boiler circ pump and a second circ pump on the other side of the hx. Both pumps always operate at the same time. 

Hot water now moves through the boiler side of the hx and transfers heat to the output side of the hx. The output side of the hx is non-pressurized to the steel heat storage tank, with expansion space left in the top of the tank. Cold water from the bottom of the tank is received by the circ pump and pushed throught the hx, returning hot water to the top of the storage. I have no separate heat control or thermostat on the storage. It takes all the heat the boiler can deliver. If by chance storage heats to boiler output capacity, the boiler simply will reach 190, and cycle off and on based on boiler controls. Never-the-less, so long as return temp to the boiler is 150 or above,  both circ pumps will continue to operate. I have never reached a situation yet where water drawn off the bottom of storage has been above 150. Due to stratification, water at the top of the tank often exceeds 150 though. I am getting all the heat I need with this level of heat storage.

As mentioned in prior post, there is a diverter valve on the output of the hx to immediately divert hot water to a unit heater and then back to storage input. The unit heater does not strip all of the heat out of the water. The unit heater fan is operated on a thermostat to provide heat as needed.

A unique aspect of my steel storage, since it is interior to my shop, is that the tank now operates as a large radiator, and once the water is heated I rarely need to use the unit heater. In fact, the heat radiation from the tank has been more than needed, and I have wrapped an insulation blanket around the top, bottom and 3 sides of the tank to limit radiation only from the front. No fan/electricity needed for normal heat.

Sizing of the hx was not too engineered. I started with a 20 plate 3-1/2 x 8. It was adequate, but the boiler delivered far more heat than this hx could strip, so the boiler regularly cycled off and on. I now have a 30 plate 5 x 12, 1" inlets and outlets. This does have the capacity to take all the heat the boiler delivers, actually more, and I am very satisfied. 

My boiler circ pump is a used Taco 009 which I had on hand, and the output side to storage circ pump is a Taco 007. I am aware of the corrosion issue with this pump on the open non-pressurized storage side, but for the cost of this pump and steel tanks, what the heck.

The only remedy for corrosion, and just to provide some protection for the hx, is a high temp water filter (50 micron) on the supply side from the tank to the hx. This filter needs to be changed every week to 10 days, and it is usually is full of a rusty slime which I suspect is coming from the steel tank (a used fuel oil tank).

I am quite certain I will install a 1200-1600 gallon buried, insulated concrete septic tank next summer for storage. Should eliminate corrosion problems of any significance and provide heat for a week or longer for my shop with no boiler firing.

Hope this helps.


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## Eric Johnson (Jan 10, 2008)

Robert,

My point, and perhaps TC's, was that when you factor hot water storage into the equation, which most of us have, you have to decide between pressurized or nonpressurized storage. If you go with nonpressurized storage, which most of us have, then you need a heat exchanger anyway. So if you decide to go with nonpressurized storage, then it's a moot point and shouldn't be the determining factor in your choice of a boiler. Pressurized storage allows your whole system to remain pressurized, but then you need a pretty big expansion tank, which has about the same degree of extra complexity and expense as a discreet nonpressurized tank and heat exchanger. I don't know f that makes sense, but it's the best I can do first thing in the morning.

Jim,

The guys with Garns treat their water and are able to eliminate corrosion. The Garn is a nonpressurized, steel system like your tank. I'm told they test water quality with a piece of steel wool. You put the steel wool into the water and see if it rusts. If it does, you add more chemicals. I'm sure the Garn guys will correct me if I'm wrong. A cast iron Taco 007 costs about $30 on Ebay. I used one for 5 years pumping fresh domestic water between a hot water heater and a coil in my old boiler, and it was still working when I eventually tore it out of there. I bet the corrosion potential in an oxygen depleted environment like your tank is even less.

I don't understand how you recover heat from your tank. Sounds like you're set up to efficiently store it, by circulating water from the bottom of the tank through the hx and depositing the heated water into the top. The best way to recover it would be to draw from the top, but that would involve some fancy piping and another pump, best as I can figure.

FWIW, Here's a diagram of what I came up with before abandoning the idea. This involves two circulators (sans flow controls) aimed in opposite directions and pumping through each other, depending on the desired function (storage or recovery). I'm not even sure that it would work, but it's the result of a lot of thought. The big advantage you have with a steel tank over a concrete tank with a rubber liner, is that you can run a pipe directly out the bottom of the tank, which solves some tricky potential problems involving pump priming and cavitation.


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## jebatty (Jan 10, 2008)

Eric -- my system is a little unique in that the area heated also contains the steel storage tank and heat principally is provided by radiation from the tank. If I run the circ pump through storage (boiler off), water draw off bottom may be fairly low, but even drawing 100-110 water through unit heater produces significant heat. And as water draw continues, water temp increases until total storage depleted. 

Another unique factor I didn't mention because it would not involve many is that actually I have 3 - 275 gallon tanks plumbed in series. Hot water from hx into tank 1 at top, out from bottom into tank 2 at top, out at bottom into tank 3 at top, and out at bottom of tank 3 to hx (or to unit heater if boiler off). Use of 3 tanks in series likely results in limited effective reduction in stratification. But keep in mind drawing from storage, other than as radiation, was not my goal. 

Actually, radiation was a bonus not planned for. I struggled with the concept of heat recover but was very pleasantly surprised by the radiation effect, thus causing me to abandon further work on more effective heat recovery. Will keep your concept in mind. Not done tinkering, however, . . . .


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## Eric Johnson (Jan 10, 2008)

Sounds like it works just fine to me. The main thing is to have enough capacity to handle the output of the boiler to keep idling to a minimum and heat the space you need to heat. Beyond that, it's just fun.

I think most of us get a kick out of playing around with these things and making them work better (or different), but once you've got the fundamentals covered, that can be a lifelong, leisure-time activity, AKA--a hobby. The great thing about a resource like this website is that we can share our experiences (and in some cases, expertise), with other enthusiasts.


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## TCaldwell (Jan 11, 2008)

robert, as eric stated for storage you will need a hx no matter what, I think alot of people would be very happy if pressureized storage was affordable, it would solve most of our problems. Being  what it is few people look beyond the desire to be independant of the oil truck, this complicates and disappoints  what should be a good experience. Some hearth members welcome this challenge for themselves and unselfishly for others, we all learn. I , in theory believe that if either system is hydronically correct , it becomes more of a preference judgement. For instance, nofossil has done his homework,and will keep on refining his system untill  it is more efficient  than most out there pressureized or not pressureized . My preference is the nonpressureized garn , extreemly simple alot of storage and a higher burn rate for rapid storage all in ONE PROVEN UNIT! If your direction is pressureized  ,calculate your heat storage requirements , investigate tanks, heat exchangers, and piping then go for the boiler you prefer that is sized to your requirements. Enough about that call me if you want to talk garn. tom


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## rvtgr8 (Jan 11, 2008)

TC,
So how do you find out more about the Garn?  Its initial appeal was the fact that it had tons of storage built into the furnace unit.  I just did calculations on a Tarm with 880 gallons of water and it was going to require a minimum of a 14' x 14' boiler room.  The Garn is huge, but does not take any more room than that set up.  One frustration that I have encountered in this process is getting much in the way detailed information from Garn.   Clearances. dimensions and most importantly price.  While I am certain that it is a good product (I don't see threads on the down sides of 'em) I have only seen one reference to price.  If it is truly a $12K unit, It might not be within my budget.  We are retired public school teachers.  I think it would have to be distinctively better quality in order to justify the extra $5K.  As I have said though, I don't know where to get the real facts.  If you are a dealer or know one who can sell me on this, I am open for a convincing pitch.  I am sold on the gasification.  I am in awe of all of the knowledge that is present within this forum.  I will do all of the math and when I arrive at the decision, I will buy an adequately sized unit.  But this forum is much like visiting with aficionados at a cat skinning festival, everybody has a different approach.  I hope I am not offending you or anyone else  in the forum when I say, You guys are damned serious about this topic.  I appreciate people who are passionate about their personal interests.  I pride myself in my ability to teach, but I live only so long as I continue to learn.  Thank all of you who are helping me to do just that.

Robert


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## Eric Johnson (Jan 11, 2008)

Well here's the deal, Robert: Most people pay a contractor to install a furnace or boiler in their basement, and then they set the thermostat at the beginning of the heating season, pay the monthly fuel bills and forget about it. People who are happy doing that are probably not the best candidates for central wood heat.

Most of us, on the other hand, found ourselves researching our options, designing our system, installing it ourselves, and then had to learn how to operate it. We're filling it with fuel once or twice a day, monitoring its performance (with varying degrees of obsession), and always trying to make it work better (ibid). And when we're not doing that, we're finding, processing and handling fuel to run it. That and spending our spare time hanging around the Boiler Room talking about it.

So you've been warned--it gets into your blood.


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## bjleau (Jan 11, 2008)

rvtgr8

I'm new to this as well and lurking and learning form all the wood fuel yodas out here. I just got some info on the Garn and still have not seen one but it is looking like about 10K for the 1500 gallon and 12K for the 2000 gallon + pipe + hook up parts. Now having done some of the math cost of EKO Tarm etc.. + storage and taking into consideration where to put it  (Taking space in the pole barn v/s workshop in our house) I'm leaning tward a Garn as well. 

At the risk of highjacking your thread....(hear me out, I'm thinking this might be useful for all newbies)
Can one of the Garn owners describe how you start your fire and the time involved in doing that. How often do you need to feed it. I'm a little worried that my wife and kids will not be able to add fuel to the EKO, Tarm etc... Especailly after reading one of the post in this thread about smoke, flames and burning eyebrows...I want to heat the house not cook the kids.

Could you also describe the quantity, quality and moisture content of your wood. Can you burn downed and kind of rotten but dry wood?

Thanks in advance for all the advice  "all knowledge begins with experience" Kant

Brian

  "all knowledge begins with experience" Kant


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## Nofossil (Jan 11, 2008)

bjleau said:
			
		

> rvtgr8
> 
> I'm new to this as well and lurking and learning form all the wood fuel yodas out here. I just got some info on the Garn and still have not seen one but it is looking like about 10K for the 1500 gallon and 12K for the 2000 gallon + pipe + hook up parts. Now having done some of the math cost of EKO Tarm etc.. + storage and taking into consideration where to put it  (Taking space in the pole barn v/s workshop in our house) I'm leaning tward a Garn as well.
> 
> ...




I have an EKO 25. Loading is simple and the wife / kids / cat can do it. The trick is to wait until the flue temp has dropped, indicating that the fire has started to die down a bit. You don't want to load it when it's cranking at full output. Mine is in the basement and is quite civilized.

You need dry wood to start it, but startup is under 10 minutes (5 with practice) and it can burn pretty much anything once it's going. You want to avoid a load that's too much of any one thing - too much green wood or too much really small wood are both bad.


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## Eric Johnson (Jan 11, 2008)

Welcome to the Boiler Room, Brian.

We have some guys who are pretty Garn good about sharing their passion for their favorite boiler.

For the record, the smoke is not a big deal with the EKO, which is the only brand I can comment on, since it's the only one I've operated. Like everything else with wood heat, experience is the key. And since you have the Boiler Room at your disposal, the learning curve just got a lot smaller. I have had a face full of smoke, but never come close to singing any body parts. I'd say they're very safe to operate--safer than a conventional wood-fired boiler, if for no other reason than there's no creosote and the chimney temps are much lower than any wood stove.

I have to disagree with nofossil on the cats, though. When I send my wife's cats out to the barn to load up the boiler (usually when it's below zero), they come back all singed up. I think that's because they seem to be naturally curious, and they try to play with the dancing flames. I keep telling them they're going to get killed if they screw around like that, but they never listen to me.


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## verne (Jan 11, 2008)

sorry for invadeing this post , but I have a question and i dont think its worth another topic. 
What do you guys think of burning pallet wood? The wood is 80% hardwood on average and it is definitly dry because the company has dryers.The pallet wood is all in pieces. stringers and top and bottom pieces. Problem the nails?? the nails are either sheared or cut so the top bottoms  have three rows three nails each , so I quess you could cut them out . But the heavy stringers have nails all the way. My friend burns only this in his wood furnace and says the pile of nails actually holds heat .what do think about it in an eko .I will be installing mine in the spring.A free tractor load is  about 8 cord. Thanks


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## Nofossil (Jan 11, 2008)

I think this should be another topic - lots of territory to be explored.



			
				verne2 said:
			
		

> sorry for invadeing this post , but I have a question and i dont think its worth another topic.
> What do you guys think of burning pallet wood? The wood is 80% hardwood on average and it is definitly dry because the company has dryers.The pallet wood is all in pieces. stringers and top and bottom pieces. Problem the nails?? the nails are either sheared or cut so the top bottoms  have three rows three nails each , so I quess you could cut them out . But the heavy stringers have nails all the way. My friend burns only this in his wood furnace and says the pile of nails actually holds heat .what do think about it in an eko .I will be installing mine in the spring.A free tractor load is  about 8 cord. Thanks



My $,02:

If you burn only pallets, you would need to adjust your primary and secondary air inlets. Pallet wood has LOTS of surface area compared to normal firewood. It will generate enormous amounts of 'producer gas' - the flammable gases that make secondary combustion possible. It's likely that it will generate so much that you won't have enough secondary air to mix with it. You will also get frighteningly high secondary combustion temperatures, because there's no water vapor to moderate the combustion.

It will burn very well, but it's quite different from the nominal wood mix that the boiler was likely calibrated for. I don't know enough yet to tell you how to make the necessary adjustments.

I'd suggest mixing it with some larger and greener pieces of normal firewood.


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## Eric Johnson (Jan 11, 2008)

That's a god question. Like nofossil said, wood that's too dry or too small can cause problems, because these boilers were designed to burn typical dry hardwood. But I think if you mixed dried pallet wood in with some green or semi-green chunk firewood (or similar) you could find a mix that  would work well. As to the nails, I don't see a problem, other than having to clean out the ash pit more often. Maybe somebody else has other ideas, but I can't see what it would hurt. Over time the scrap value would start to add up if you sifted them out of the ashes.


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## chrisfallis (Jan 11, 2008)

I owned a Tarm for 4 years and saw a Garn operated only once, but I will give you my impressions.  The Tarm was pretty easy to start.  Throw in some paper, cardboard and knindling, light, shut the door, start the draft fan and come back in a few minutes to check.  I would then thrown in some scrap lumber and give it a few minutes to make sure the secondary combustion was going (gotta love that view port).   Finally I would pack the firebox and go on about my business.  This sounds like a 5 to 10 minute process, and while time consuming, it was theraputic "alone" time for me.  I could bring in another trash barrel of wood from outside, tidy up the basement, putter, watch the boiler temps rise, etc.  If I was a smoker, this would have been the perfect time to light one up.  I am sure some of the other readers know about this mostly male phenomenon, where you stand around machinery, watching it and thinking, "boy, this is cool".  I fed the Tarm kiln dry scrap wood and seasoned split pine.  The few times I tossed in "greenish" branches, I could see the water boiling out the ends with no secondary combustion going on.  Learn from your mistakes!
I started the fire about once a day, depending on weather.  I never perceived that this was a burden.

The Garn that I saw in Santa Fe, New Mexico was super easy to start.  A ball of newspaper, some sticks, apply match, close door and start fan.  Come back in 5 miutes and add wood to coals.   Add more wood in 15 to 20 minutes, set and forget.  Fuels being used in Santa Fe were pretty dry since the town is in a very arid location.  They burned pine, scrub oak and wood-shaving briquettes to see what worked the best.  The owner said there was a learning curve to get the most heat from this boiler, but it was being fed by students and security guards at the college where it is installed.  In orther words, a monkey could do it.  After the fire was established and the loading door was opened, there was so much radiant heat that you had to step back.  The scceonday combustion takes place in the ceramaic refractory in the the far back end of the firebox,  but between the glowing bed of coals in the front and the white hot gasses in the back of the firebox, it ws pretty darn intense.  Youngsters and wives and more timid souls might be tempted to stand 5 feet away and launch wood into the unit. Those of us tough guys would gently palce the wood inside so as not to damage the ceramic refractory.

My natural gas bill is about $2500 a year for heat.  That is with the thermostat at 64 degrees.  When we looked at a new heating system last year the suggestion that we got was for a new boiler for the radiators and 3 hot air furnaces to replace the 1940s vintage octopus.  With ductwork modifications and asbestos removal, we were quoted $25K.  I think that I could spend $12K for a Garn, $3-5K for piping and heat exchangers, and still be ahead of the game.   A six year payback is pretty darn good  with me.  I am assuming the fuel is free and my fire tending time is worth zero.  The wood is basically free for the scrounging, and since I am outside walking the dog anyway, a few trips to the backyard garage each mornig would not be a burden.


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## verne (Jan 11, 2008)

Thanks no fo and Eric. I dont think I would burn just pallets any way but the nails were a concern .I just shoveled up a large pile left from newyears.Thanks again  and  I will continue to read and learn


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## chrisfallis (Jan 11, 2008)

I burned pallet wood in my Tarm.  It was the best source of oak out here in pine country and free from a company that rebuiilt pallets.  I used a radial arm saw to cut everthing to stove length and had to watch that I didn't try to saw through nails. The nails and nail fragments just ended up in the lower combustion chamber like big clinkers.  I picked them out periodically and recycled them.  The oak 2x4s I saved for overnight burns.  The pine 1x4s did burn to fast if used alone.


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