What are your thoughts on which gassers to compare?

[Frozen Canuck]

OK, so on one hand I have the Garn 1500/2000. These look like a decent fit for us. On the other hand what should I compare them to? (Reasonable, rational, real world comparisons).

So far I have come up with Econoburn EBW300/EBW500.....Woodgun E250/E500.....Biomass80.....Eko80.....Paxo80.....all of these will be priced with storage similar to the size in the Garns.

Does anyone see units that I have missed or that they would like to see compared with the above units?

What I am looking for is a comparable burn rate to the Garns & I will add storage to it.

As always I am wide open to suggestions & appreciate your input. Thanks.

 

[Jim K in PA]

FC - it is tough to compare most downdraft style gassifiers with the GARN, since the GARN is really designed from the outset as a batch-burn unit. As far as burn rate, the 1500/2000 has input ratings of 350-450k Btuh, and I can personally attest to the higher rating being realistic with the WHS2000. Others more familiar than I with the alternatives you mention can certainly give you some guidance on comparably rated units. While I personally think the GARN is one of the best alternatives out there, it is not always the best solution for every situation. Based on my own research, and that done by many others here indicate that a properly designed system with a downdraft gasser configured with comparable storage as the GARN will usually cost about the same as a GARN. With adequate storage, the input rating is less of a concern as long as you exceed your maximum design load. If you have room for the GARN, it is hard to find fault with its efficiency and ease of operation.

The key question is, have you done a load calculation? If so, share your data and more specific suggestions might be possible.

 

[Frozen Canuck]

Thanks for the response Jim. We consume 40k btu/hr at -40. This temp can stay for awhile here so we are trying to design around it. Agree on storage 100% it will be a part of whatever system we go with. Have to disagree on fire rate. I am already married & will never consider getting a boiler that doesnt fit my schedule for firing.....namely max 3 times per day, morning before work, evening upon return from work & 1 more fire before bed. That is it max. No wiggle room in my schedule at all. Please check my post on Dec 16 to get an idea of what I have available as fuel source. This fuel source works for us now with a OWB. We just think a gasser is a better way to go. Thanks.

 

[ISeeDeadBTUs]

http://www.viessmann.co.uk/prod_vitolig300.php

 

[Jim K in PA]

OK - read through your other thread. We need to clear up a couple of terms.

With respect to a GARN, which is all I have experience with, a "burn" for me is the amount of time I fire the unit to raise the storage water temperature from wherever it is, to whatever I want it to be. That could be 130-200, 150-180, etc. It may take 1 or more burn CYCLES to get the desired temperature rise. A single burn cycle is, in my own little world, a single load of wood that is consumed. You do not "stoke" a GARN, and you only reload after a cycle is largely complete. I do not always need to reload, but if I do I wait until the flue temp is down around 200-250 F.

A load of wood in a GARN will burn down in anywhere from 45 minutes to 2 hours, depending on density. The temp rise can be anywhere from 15-30 degrees over the course of a burn cycle. There is no way you can get 1M Btu's in a single burn cycle (single load of wood). Based on your estimated heat load, you can easily get by on two burn cycles in the AM, and two in the evening. Even with your "bad" wood.

The total amount of time taken up for the entire days heating effort should not be more than 15-20 minutes. Seriously. I am in the same boat you and most other people are with respect to time demands. Wife, kids, job, blah blah. For a very high heat load day (35-40k Btuh), I get up at 5AM (my normal hour to get up), throw a load of wood in the GARN and light it. I go back in the house, eat breakfast, take a shower, make my kids lunch, make my lunch, and do whatever other morning chores I have to do. Before I leave for work, about 60-90 minutes later, I throw another load of wood in the GARN, set the timer for 90 minutes or so, and leave for work. I do not watch, babysit, or otherwise stick around to tend the thing. It is dead simple, safe, and easy. In the evening, if I feel the need to have another burn, I will repeat the process.

You will NOT be able to burn 16"x48" rounds in a GARN. I burn plenty of low density wood in my GARN, and I still split my pine rounds down to 8-12"x20". Oak and other hardwoods get split smaller. The GARN will burn most efficiently if you can the fuel to burn completely and quickly. You should NOT completely pack the firebox solid with wood. I also burn PLENTY of "less than desirable" wood that is punky, but dry. I am AMAZED at how much energy this "bad" wood still has in it. Certainly not the same as a load of nicely seasoned hard oak, but it is certainly worthy of the effort to get it in the fire box, IMO.

You may well be able to find another system that can develop the heat output you want, but I cannot make any suggestions because I am unaware of them. I have repeatedly checked and confirmed the GARN WHS2000 input rating of 425k Btuh. With good fuel I actually exceeed it by 5% or so regularly. That means with a 2000 you will need 2-3 hours of firing per day to meet your 1M Btu/day goal. This HAS to be more reasonable than the amount of effort, and fuel, you are putting into your OWB.

Hope this helps.

 

[Frozen Canuck]

http://www.viessmann.co.uk/prod_vitolig300.php

Yes, thought of these, as well as Froling, pretty pricey, also the ones for sale here have a max 20 long piece of wood. I would need 2 of them to accomplish what I want. Think that amounts to $40k. Sweet unit just too pricey. Maybe if they decide to sell the big ones here.

 

[Frozen Canuck]

OK - read through your other thread. We need to clear up a couple of terms.

With respect to a GARN, which is all I have experience with, a "burn" for me is the amount of time I fire the unit to raise the storage water temperature from wherever it is, to whatever I want it to be. That could be 130-200, 150-180, etc. It may take 1 or more burn CYCLES to get the desired temperature rise. A single burn cycle is, in my own little world, a single load of wood that is consumed. You do not "stoke" a GARN, and you only reload after a cycle is largely complete. I do not always need to reload, but if I do I wait until the flue temp is down around 200-250 F.

A load of wood in a GARN will burn down in anywhere from 45 minutes to 2 hours, depending on density. The temp rise can be anywhere from 15-30 degrees over the course of a burn cycle. There is no way you can get 1M Btu's in a single burn cycle (single load of wood). Based on your estimated heat load, you can easily get by on two burn cycles in the AM, and two in the evening. Even with your "bad" wood.

The total amount of time taken up for the entire days heating effort should not be more than 15-20 minutes. Seriously. I am in the same boat you and most other people are with respect to time demands. Wife, kids, job, blah blah. For a very high heat load day (35-40k Btuh), I get up at 5AM (my normal hour to get up), throw a load of wood in the GARN and light it. I go back in the house, eat breakfast, take a shower, make my kids lunch, make my lunch, and do whatever other morning chores I have to do. Before I leave for work, about 60-90 minutes later, I throw another load of wood in the GARN, set the timer for 90 minutes or so, and leave for work. I do not watch, babysit, or otherwise stick around to tend the thing. It is dead simple, safe, and easy. In the evening, if I feel the need to have another burn, I will repeat the process.

You will NOT be able to burn 16"x48" rounds in a GARN. I burn plenty of low density wood in my GARN, and I still split my pine rounds down to 8-12"x20". Oak and other hardwoods get split smaller. The GARN will burn most efficiently if you can the fuel to burn completely and quickly. You should NOT completely pack the firebox solid with wood. I also burn PLENTY of "less than desirable" wood that is punky, but dry. I am AMAZED at how much energy this "bad" wood still has in it. Certainly not the same as a load of nicely seasoned hard oak, but it is certainly worthy of the effort to get it in the fire box, IMO.

You may well be able to find another system that can develop the heat output you want, but I cannot make any suggestions because I am unaware of them. I have repeatedly checked and confirmed the GARN WHS2000 input rating of 425k Btuh. With good fuel I actually exceeed it by 5% or so regularly. That means with a 2000 you will need 2-3 hours of firing per day to meet your 1M Btu/day goal. This HAS to be more reasonable than the amount of effort, and fuel, you are putting into your OWB.

Hope this helps.

Agree with all you have said, my comment related to units with smaller fireboxes as they would require more loads of wood...therefore more time., to get the same btu into storage.

Question: can you not burn large rounds due to shape of wood not supporting a good (fast) fire therefore poor gassification?
Or are there other reason(s)?
Why do you cut at 20"?
Does this length support better gasification?
My thought is max length possible without disrupting gassification. Sound right?

 

[sdrobertson]

OK, so on one hand I have the Garn 1500/2000. These look like a decent fit for us. On the other hand what should I compare them to? (Reasonable, rational, real world comparisons).

So far I have come up with Econoburn EBW300/EBW500.....Woodgun E250/E500.....Biomass80.....Eko80.....Paxo80.....all of these will be priced with storage similar to the size in the Garns.

Does anyone see units that I have missed or that they would like to see compared with the above units?

What I am looking for is a comparable burn rate to the Garns & I will add storage to it.

As always I am wide open to suggestions & appreciate your input. Thanks.

I'm using a EKO60 and my father has the 80. Great boilers and they work really well. The one problem I see with both is that in the 60 and even more in the 80 there is allot of ceramic to warm up when you first build the fire. It takes allot of BTU's to get everything hot enough to really get them cooking. They'll burn clean at the start, but to really put out the heat they do have to heat up. The more I read about and watch the Garns, if you have sufficient head load, and you have room to place them, I can't think of a better boiler. I haven't seen a Econoburn, Woodgun, or the Biomass so take that into consideration also. Once again, I love my EKO but if I was to do it all again, I'd go with the Garn.

 

[Jim K in PA]

Agree with all you have said, my comment related to units with smaller fireboxes as they would require more loads of wood...therefore more time., to get the same btu into storage.

Question: can you not burn large rounds due to shape of wood not supporting a good (fast) fire therefore poor gassification?
Or are there other reason(s)?
Why do you cut at 20"?
Does this length support better gasification?
My thought is max length possible without disrupting gassification. Sound right?

The GARN box is only 41" long. There are two air "nozzles" or ports at the door opening that feed air to the primary combustion and the secondary compbustion. You need to have adequate flow at the front of the fire box to feed the fire properly, and you need space around the wood to let air reach the rear of the firebox so it supports secondary combustion in the refractory lined SRC. 8-10" of free space at both ends is about right to let everything work properly. That makes 20" long splits just about perfect, from my experience. If the wood is too close to the front it burns too quickly, causing "puffing".

 

[Frozen Canuck]

OK, so on one hand I have the Garn 1500/2000. These look like a decent fit for us. On the other hand what should I compare them to? (Reasonable, rational, real world comparisons).

So far I have come up with Econoburn EBW300/EBW500.....Woodgun E250/E500.....Biomass80.....Eko80.....Paxo80.....all of these will be priced with storage similar to the size in the Garns.

Does anyone see units that I have missed or that they would like to see compared with the above units?

What I am looking for is a comparable burn rate to the Garns & I will add storage to it.

As always I am wide open to suggestions & appreciate your input. Thanks.

I'm using a EKO60 and my father has the 80. Great boilers and they work really well. The one problem I see with both is that in the 60 and even more in the 80 there is allot of ceramic to warm up when you first build the fire. It takes allot of BTU's to get everything hot enough to really get them cooking. They'll burn clean at the start, but to really put out the heat they do have to heat up. The more I read about and watch the Garns, if you have sufficient head load, and you have room to place them, I can't think of a better boiler. I haven't seen a Econoburn, Woodgun, or the Biomass so take that into consideration also. Once again, I love my EKO but if I was to do it all again, I'd go with the Garn.

Thanks for the response & the honesty. I really appreciate it. I think it would be a good thread for you experience gassers to start " what my unit does well & what it needs to improve on ". Most if not all of us that are considering this as an option (gassification) would benefit from the knowledge base here. "Some" of the experienced ppl need to play their cards a little further from the vest & share their huge knowledge base. I think you will find that most of us "noobs or wanna be's". Will be more than willing to listen to an honest discussion by the "been there done that" crowd. Once again thanks for sharing.

 

[Jim K in PA]

The more I read about and watch the Garns, if you have sufficient head load, and you have room to place them, I can't think of a better boiler. I haven't seen a Econoburn, Woodgun, or the Biomass so take that into consideration also. Once again, I love my EKO but if I was to do it all again, I'd go with the Garn.

This is a common misconception with the GARN. Unless you have a commercial greenhouse to heat, a GARN cares little about your heat load. It is a batch burn heating unit, which means that you do not burn it at a rate that is dependent on heat load. A GARN burns flat-out at up to 450K Btuh (with good quality fuel) whenever you light it. The heat load is met by drawing from storage, and the GARN can readily meet any typical domestic heating load and recharge the storage simultaneously. The heat load put upon the GARN only dictates how frequently you recharge the storage. Days like today with temps barely in the teens and winds blowing at 40-50mph, my heat load shoots up to 70k Btuh. On days like this I need to burn for about 2 hours in the AM, and 2 hours in the PM, as my usable water temps are between 200 and 130F. That range gives me just over a million Btus. If I average 70k Btuh heat load over 12 hours, I can readily meet that 850k Btu demand with a 2-3 hour burn.

Your statement about placement is 100% correct. It is a BIG MUTHA! :coolgrin:

<not pickin' on ya SD, just using your statement above as a point of discussion ;-) >

 

[DaveBP]

If you need something larger than the usual big residential units, you could talk to these guys on your side of the border:

http://www.finkmachine.com/wood_boilers.html

 

[Frozen Canuck]

Agree with all you have said, my comment related to units with smaller fireboxes as they would require more loads of wood...therefore more time., to get the same btu into storage.

Question: can you not burn large rounds due to shape of wood not supporting a good (fast) fire therefore poor gassification?
Or are there other reason(s)?
Why do you cut at 20"?
Does this length support better gasification?
My thought is max length possible without disrupting gassification. Sound right?

The GARN box is only 41" long. There are two air "nozzles" or ports at the door opening that feed air to the primary combustion and the secondary compbustion. You need to have adequate flow at the front of the fire box to feed the fire properly, and you need space around the wood to let air reach the rear of the firebox so it supports secondary combustion in the refractory lined SRC. 8-10" of free space at both ends is about right to let everything work properly. That makes 20" long splits just about perfect, from my experience. If the wood is too close to the front it burns too quickly, causing "puffing".

Thanks for the response. That clears it up about what you are finding that works for clearance in the firebox. I just realized that if I want to keep burning 48" then I need to find a manufacturer that makes a 70" long firebox. Wow thats one big boiler!! :bug: Oh well back to the www. in search of huge boilers Ha ha ha just kidding, you know us OWB-SOB's no one will ever build a big enough firebox. :snake: Thanks for sharing it really does help

 

[leaddog]

The biggest problem with really long wood is getting it dry. I have the eko 80 and can use 40in wood but it takes a long time to dry that long of wood. I do like to cut my real small limbs (1 to 2in ) long as that saves work and I would probaby not cut them otherwise but the bigger stuff would not dry well and not fit my splitter.
AS far as the eko80,I like mine. It was a good fit for me as I was able to put it in myself and put in the 4 propane tanks with insulation that I got cheap. (used walkin freezer panels etc that I got for $20) I go to auctions and yard sales and watch for bargins and picked up most of my plumbing so it was relitive cheaper. In the shoulder seasons I have more trouble starting a fire and bringing up the tanks to temp but that is mostly my fault as I hate to wait for a coal bed. Hard to teach an old guy new tricks. When it is cold I never have to start a fire as there is always coals.
I also like the closed system as it has several advantages over the garn open system. But if the money is equal I'd go with the garn because of the ease of use. I have less than $10,000 in mine with every thing so it was a big cost savings for me.
I don't think you will go wrong with any one of the major brands of gasifiers. You need to look at what you need and your requirments are and make you selection on that. every one has there pluses and minuses.
leaddog

 

[Frozen Canuck]

The biggest problem with really long wood is getting it dry. I have the eko 80 and can use 40in wood but it takes a long time to dry that long of wood. I do like to cut my real small limbs (1 to 2in ) long as that saves work and I would probaby not cut them otherwise but the bigger stuff would not dry well and not fit my splitter.
AS far as the eko80,I like mine. It was a good fit for me as I was able to put it in myself and put in the 4 propane tanks with insulation that I got cheap. (used walkin freezer panels etc that I got for $20) I go to auctions and yard sales and watch for bargins and picked up most of my plumbing so it was relitive cheaper. In the shoulder seasons I have more trouble starting a fire and bringing up the tanks to temp but that is mostly my fault as I hate to wait for a coal bed. Hard to teach an old guy new tricks. When it is cold I never have to start a fire as there is always coals.
I also like the closed system as it has several advantages over the garn open system. But if the money is equal I'd go with the garn because of the ease of use. I have less than $10,000 in mine with every thing so it was a big cost savings for me.
I don't think you will go wrong with any one of the major brands of gasifiers. You need to look at what you need and your requirments are and make you selection on that. every one has there pluses and minuses.
leaddog

No problem for me getting the wood dry. I have lots of time & lots of space. I have wood now 48"x16"-24" that has been drying 36 months plus. Thats ok I can wait for it. If need be I will build a splitter for 48" wood I have a tractor loader cylinder with a 56" stroke thats ready to be used. Mine will be a DIY install as well & yes I go to auctions etc, why not plenty of new or next to new product for 10% of new. You got yours installed for a good total price, 10k is attractive compared to 20k plus. Thanks for sharing how your unit works for you, as well as what you might do different. I see you got smart & got storage, burn full tilt till shes gone then repeat. Me I am still looking for a 10,000 gallon tank (cheap). ;-)

 

[jebatty]

See my post here for comment on a similar question.

 

[mwk1000]

I’m using a EKO60 and my father has the 80. Great boilers and they work really well. The one problem I see with both is that in the 60 and even more in the 80 there is allot of ceramic to warm up when you first build the fire. It takes allot of BTU’s to get everything hot enough to really get them cooking. They’ll burn clean at the start, but to really put out the heat they do have to heat up. The more I read about and watch the Garns, if you have sufficient head load, and you have room to place them, I can’t think of a better boiler. I haven’t seen a Econoburn, Woodgun, or the Biomass so take that into consideration also. Once again, I love my EKO but if I was to do it all again, I’d go with the Garn.

I also have an EKO 60, and I agree with the startup comment. We really need to be burning well for an hour before it starts to drive the water temps very high. On the positive side it is still heating after the fire is gone for that same hour. I personally love the Garn except for the price tag. I set about doing my low cost emulation with the EKO + 1500 gal of open storage. I use about 60,000 BTU/hr at 10 degrees outside and can fire once a day with one reload. Load at 6pm reload at 11pm in the morning the tank is 165-170 or better at 6 am -- that will last till 6pm.

I made a little table for my tank to help day to day, it holds 894000 BTU's on a good fill (I can operate from 175-100 = 75 * 11920 lbs ) so my table is like this:

Outside BTU-LOAD TankDrop/HR Reload Hours ( With 6 Hour burn added )
-15 91393 7.67 15.13
0 75265 6.31 17.09
20 53761 4.51 21.52


My table is a little more conservative assuming I did NOT get a perfect burn and over the last 1 year it has been dead on accurate. When the wife wants to know if she needs to start a fire I have her check the chart to see how many hours left before we start getting to 100.

A good note for the EKO 60 ( For me at least ) 1 load will heat the house for 6 hours and charge 500 Gal to max, 2 loads 12 hours and 1000 Gal to max 3 loads = 18 hours and 1500 gal to max where max is 185. Just last Saturday I did 3 burns with 5 degree outside temps and had a 183 tank temp. So as I see it I am at the largest tank size for an EKO 60 that I would want, Closed storage would help but I am tuning now to get the most possible from my HX. The difference between a Garn and me is the efficiency of the transfer is nowhere near as good. From what I have seen in the videos and photos on the web I use a lot more wood to get my 1500 gal to the same temps as the Garn. Except that a Garn could reach 200 adding another 238000 BTU's to 1500 gallons of water -- That I will never see, you get what you pay for -- and I have about 11K into a finished system so I am happy with the compromise.

 

[Frozen Canuck]

See my post here for comment on a similar question.

Yes, I have been giving thought to heat loss, no matter where in the system it occurs, if I go with a Garn I will insulate both the intake & exhaust with a foam plug. One advantage of horizontal flue, easy access. The storage tank, Garn or otherwise will get an R-value of at least 50. From there on out its the smaller heatlosses & effiencies.

 

[Frozen Canuck]

I’m using a EKO60 and my father has the 80. Great boilers and they work really well. The one problem I see with both is that in the 60 and even more in the 80 there is allot of ceramic to warm up when you first build the fire. It takes allot of BTU’s to get everything hot enough to really get them cooking. They’ll burn clean at the start, but to really put out the heat they do have to heat up. The more I read about and watch the Garns, if you have sufficient head load, and you have room to place them, I can’t think of a better boiler. I haven’t seen a Econoburn, Woodgun, or the Biomass so take that into consideration also. Once again, I love my EKO but if I was to do it all again, I’d go with the Garn.

I also have an EKO 60, and I agree with the startup comment. We really need to be burning well for an hour before it starts to drive the water temps very high. On the positive side it is still heating after the fire is gone for that same hour. I personally love the Garn except for the price tag. I set about doing my low cost emulation with the EKO + 1500 gal of open storage. I use about 60,000 BTU/hr at 10 degrees outside and can fire once a day with one reload. Load at 6pm reload at 11pm in the morning the tank is 165-170 or better at 6 am -- that will last till 6pm.

I made a little table for my tank to help day to day, it holds 894000 BTU's on a good fill (I can operate from 175-100 = 75 * 11920 lbs ) so my table is like this:

Outside BTU-LOAD TankDrop/HR Reload Hours ( With 6 Hour burn added )
-15 91393 7.67 15.13
0 75265 6.31 17.09
20 53761 4.51 21.52


My table is a little more conservative assuming I did NOT get a perfect burn and over the last 1 year it has been dead on accurate. When the wife wants to know if she needs to start a fire I have her check the chart to see how many hours left before we start getting to 100.

A good note for the EKO 60 ( For me at least ) 1 load will heat the house for 6 hours and charge 500 Gal to max, 2 loads 12 hours and 1000 Gal to max 3 loads = 18 hours and 1500 gal to max where max is 185. Just last Saturday I did 3 burns with 5 degree outside temps and had a 183 tank temp. So as I see it I am at the largest tank size for an EKO 60 that I would want, Closed storage would help but I am tuning now to get the most possible from my HX. The difference between a Garn and me is the efficiency of the transfer is nowhere near as good. From what I have seen in the videos and photos on the web I use a lot more wood to get my 1500 gal to the same temps as the Garn. Except that a Garn could reach 200 adding another 238000 BTU's to 1500 gallons of water -- That I will never see, you get what you pay for -- and I have about 11K into a finished system so I am happy with the compromise.

Thanks for the info on your system as well as the comparison. Efficiency of transfer matters, less wood to do the same work. So does total cost. Also trying hard to get a handle on total life cycle costs of each system, that for me is probably the biggest factor in a system that lasts 20+ years. Just wondering out loud how the total life cycle costs compare A vs B, etc, etc, etc.