EKO 40 efficiency?

[68dodgeramman]

We're on the verge of buying the Orlan EKO-40 without storage tanks to start with. We have 2500 sq. ft. main floor and basement and 840 sq.ft. of attached garage to heat along with DHW. We're in Northeastern Lower Michigan. Our neighbor has the traditional style wood stove about the same sq. ft. and says he burns 18 face cord a season. Which should be about 6 full cords. Another guy has a central boiler system with the water jacket and he has 5000 sq. ft. to heat. He says he uses about 30 face cord, which should be about 10 cord. I called CozyHeat and he says I can figure on six cord or less. Are my figures wrong? Because these numbers don't seem to be that much better than these other stoves as far as effeciency. What have some of you owners burned on average in a season? We're just wondering if it's worth the extra expense. Thanks.

 

[Nofossil]

There are a lot of variables besides square footage. Solar gain, insulation, air infiltration, thermostat setting, wind exposure, firewood species and moisture content all make potentially huge differences in the amount of wood that it takes to heat a house.

All things being equal, a gasification boiler operated efficiently will burn about 40% less wood than a conventional boiler, and usually much less than half as much as a typical OWB.

Without storage, any boiler is less efficient. If you keep it burning 24/7, it will be idling most of the time, and an idling gasifier isn't much more efficient than anything else. If you plan your burns carefully and resign yourself to making a fresh fire at least once a day, you can still get really good efficiency with a gasifier without storage. Storage just makes it more convenient.

I heated our house (3500 square feet) as well as DHW and a hot tub for 3.2 full cords, mid-November through mid-March with no storage.

In following years, we heated from mid-October through mid-April and have averaged a little over 4 cords per year with storage.

We keep the house around 72 degrees, and our wood is not premium hardwood - it averages about 1/3 poplar, red cedar, and white pine.

 

[sdrobertson]

I'm guessing the one that uses 6 cords is a wood stove...your trying to compare different units as one heats the air and the other heats water which then you can use radiant or a air handler in a furnace. I would agree with Cozy as to a wild guess on wood consumption but without a complete description of your house its hard to just stab at a number of cords. There is no doubt that you'll go through at least half the wood with a gasifer than a OWB. The advantage to a boiler is that its easier to regulate the temps in the house as opposed to a stand alone wood stove and you also can heat your domestic hot water. The other advantage is with the gasifer, you get a much cleaner burn with less smoke going out the chimney.

 

[flyingcow]

Another rough way to figure things......
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-Gassifier, 1 cord of hardwood=150gals of oil(may=more oil when you're tuned in)
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OWB 1cord of wood=100gals of oil. IMHO thats pushing it.
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My wood usage is very close to those figures. I'm hoping to do better next yr or two.
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BUT, best to do a load calc. Then you should size things up right. Spending alot of money, be good to get it as close as possible.
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Also i have a 1800sq/ft 2 storyhouse, 3 kids, windy cold as hell up here. Average insulation. I'm on track to use 6 to 6 1/2 cords a year. Thats including DHW, year round burning.

 

[taxidermist]

We're on the verge of buying the Orlan EKO-40 without storage tanks to start with. We have 2500 sq. ft. main floor and basement and 840 sq.ft. of attached garage to heat along with DHW. We're in Northeastern Lower Michigan. Our neighbor has the traditional style wood stove about the same sq. ft. and says he burns 18 face cord a season. Which should be about 6 full cords. Another guy has a central boiler system with the water jacket and he has 5000 sq. ft. to heat. He says he uses about 30 face cord, which should be about 10 cord. I called CozyHeat and he says I can figure on six cord or less. Are my figures wrong? Because these numbers don't seem to be that much better than these other stoves as far as effeciency. What have some of you owners burned on average in a season? We're just wondering if it's worth the extra expense. Thanks.

I have a eko 60 and a 3700sqft of heated space with 1000gal of storage. With the learning curve of the new system and lack of kindling last year to start fires with I used 12 face cord to heat my house and DHW from Dec. to late march. I figure this year I should be around 10fc if we have a winter like last year and I will start burning after nov 15 till the wood runs out.


(I got the eko 60 to heat my barn also in the future) I could have got the 40 to do my house.

Rob

 

[68dodgeramman]

Thanks for the replies everybody. I guess my main concern is; if I install the EKO 40 without storage tanks will it be an inefficient wood boiler? Is it useless to do it without the tanks? Or will it be alright? And on an other note, will this thing chug smoke real bad not being set up with the extra storage? I know these probably sound pretty stupid but I'm just trying to get a good idea of what to expect as the only experience I've had with burning wood has been in the fire pit in the back yard, the old Ben Franklin at the hunting camp and my parents basement wood stove from 30 years ago. Lol.

 

[Nofossil]

The EKO idles pretty well by all reports, and even without storage a gasifier is way more efficient than conventional boilers. I ran mine wothout storage the first year and used 3.2 cords from mid-November to mid-March.

It does make a difference how you operate it. If you keep it burning 24/7, it will idle a lot more than if you let it go out between fires. A really good compromise is to load it up partway, let it burn to coals, and repeat. Gasifiers idling with coals aren't losing much. Idling with a full load of wood is a lot more wasteful.

 

[Medman]

I am burning half-loads right now in my EKO without storage. Typically, I light a fire around 7 pm, reload at 11 pm, let it go out. During the evening I set the thermostat higher to heat the slab, then set it back down at 11 pm and leave it there until the next night. The house is cooler in the afternoon, but no one is there to notice it. This routine is enough right now to keep the DHW hot and the house at 70* at night, 67* during the day. Even with half loads of white birch, I experience some idling. Storage adds convenience for time of burning, but not that much efficiency if the boiler is tuned correctly.

The other thing to consider is the quality of the heat when comparing the woodstove to the boiler. We heated our house for four winters with the woodstove, using an average of 4 cords of maple and oak per year. Half the house was too hot, the other half too cold, the floors always freezing, and the bedrooms had to have supplemental electric heat. Now I heat with the EKO and last winter I used 7 cords, but the whole house was warm and comfortable all year (too hot for me actually - my wife likes the thermostat at 75*). No supplemental electric or propane used, and no electricity for DHW all winter. We can enjoy weekend mornings in our bare feet and long hot showers.
There is more to this equation than just the cost/wood use - there is comfort/quality of life to consider as well.

If you do a good job of tuning, you shouldn't find the EKO chugs or puffs smoke. It will smoke when loading, so using the draft inducer is a good idea.

 

[Tony H]

I started up my EKO last week and like has been said I am burning small loads and just throwing in a few splits every few hours. The house is 2800sf cape cod and the original part was built in the 40's with not so great wall insulation and we keep the heat at 72 and also heat DHW.
This is the worst time of year for efficiency along with spring and the system idles more than I would like. Even with more idle time the unit does not throw out very much smoke just a steady small trickle of light smoke. Last winter I used about 6.5 cords of wood, some was a little too wet and I have learned alot more about how to run the boiler so this year I expect to use a little less. My next door neighbor has a add on hot air furnace and he used well over 10 cords and his house is not kept as evenly heated plus he is not heating DHW and his house is a smaller newer ranch.
I do intend to add storage as it certainly would be better but I am not at all dissatisfied with the boiler running without storage.

 

[68dodgeramman]

This is all good info to know. Thanks for the replies. Now about pumps, do they run constantly? To give you some background, our house is 1258 sq ft main floor, 1258 sq ft basement with an attached 840 sq ft garage. Our plan is to have the EKO 40 in the garage with a hydronic unit heater in the garage. Then in the basement we plan on a 16x18 water to air exchanger in the plenum of our forced air furnace and a domestic water kit on our natural gas water heater. And from what I can tell from our estimate is that there is a Taco 007-F5 Pump. So We're wondering if the pumps run all the time, do they use a lot of electricity?

 

[Medman]

From what you have listed, I think you will need to add at least one pump.

The Taco 007 is for the near-boiler circuit, and if the distance from garage to furnace/DHW tank is not too great, could be used to circulate water in the primary loop as well. The second pump (or a zone valve) would be installed on the supply to the heat exchanger in your forced air furnace. When the thermostat calls for heat, the pump turns on to supply the hx (or the zone valve opens). This pump only runs during a heat call.
The same would be true of the hydronic heater in the garage, but If your garage is insulated you will not need to heat the space - the boiler and piping will take care of that. Just put in fittings to tie into later if you need them.

The main circulator runs all the time that the boiler is hot, to circulate the water through the loop, through the DHW heat exchanger and back to boiler. A Taco 007 will use about 80 watts of electricity. THe amount of electricity saved by heating your DHW with wood will offset this amount the first day of each billing cycle. For example, I spend $40-50 more per month on electricity in the summer than in the winter, just for DHW.

I have a similar system, but I use a Taco 1400-10 to move water from my garage to the house (140' each way). I use a Taco 007 on the plenum HX. I am soon going to be connecting storage per the 'Simplest Pressurized Storage' thread above, and at this point I will add another pump, a Taco 00R three speed circ, to the near boiler circuit. THe 1400-10 will become the main load circ.


First, you need to do a head loss calculation based on your piping diagram to determine if the 007 will meet your needs:

1. Do a heat-loss calculation for your heated space. This will give you the amount of heat you need to move from your boiler.
2. Determine the size/type of pipe and do a head pressure calculation based on the amount of heat you need to move.
Smaller pipe means increased velocity and higher head pressure. Larger pipe means lower velocity and head pressure but costs more.
3. Select a circulator that can give you the velocity (in GPM) you need at the head pressure you have calculated, based on the pump curves.

Taco's website has some great info for this, and there have been several threads here on exact figures to use in the above calculations.
Even if you have used an installer to determine these numbers, you should do the math yourself to make sure. Not all installers know what they are doing in this regard - as I have witnessed myself. The more you know, the better the chances that your system will function as expected the first time.

 

[Gooserider]

How much the circs run is largely a function of how you design your plumbing and control setup, along with your heat demands... However while they will probably run a lot, they aren't that expensive... If you size your plumbing properly, you can use smaller circs each of which is about equal in power draw to an old fashioned incandescent light bulb.... There are new circ designs that are more expensive up front, but cost a lot less to run as they adjust their power draw to match the actual heat demand, and this can be coupled with outdoor reset and other control strategies to reduce demand even more.

However what is, and will continue to be, the real killer in terms of energy consumption is the fact that you are heating the house w/ a heat exchanger in your HVAC system, and thus will still be running the HVAC blower... It takes HUGE amounts of power to move air around, that blower is probably pulling 1,000 - 1,500 watts, or better than ten times the amount of juice that a hot water circ will draw... Doing an air coil setup will get you up and running quickly, but won't give you much of a change in your electric bill. Since often the HX coils run at a lower temp, and require a higher fan speed because they increase airflow resistance, your HVAC fan may be running harder / longer, and your electric bill will go up slightly.

If you want to take a big chunk out of the electric, you will need to switch over to radiant panels, in-floor radiant, or other purely hydronic heating, at which point you will only be needing to power a small pump instead of a big blower....

(I am planning my own system to do this, leaving the existing HVAC setup in place as backup heat and summer AC, but doing all the primary heating by hydronics)

Gooserider

 

[burnclean]

I have been a lurker on this forum for quite a while before signing up today. I don't understand the obvious BIAS here on this forum towards EKO and downdraft gasifiers. I completely disagree that just because a stove is a downdraft it is going to be more efficient. Its NOT necessarily true The efficiency of the stove depends on two factors #1) how hot you can get your firebox or secondary chamber and #2) how much heat transfer area is built into the stove. Now #1 can be argued that downdrafts are hotter, fine. BUT the bigger factor really is #2 for efficiency. You could have a clean burning downdraft stove with a crappy heat transfer area and it wouldn't be efficient at all! It will depend on the DESIGN of the heat transfer area of the stove, has nothing to really do with it being downdraft or not.

 

[twofer]

I have been a lurker on this forum for quite a while before signing up today. I don't understand the obvious BIAS here on this forum towards EKO and downdraft gasifiers. I completely disagree that just because a stove is a downdraft it is going to be more efficient. Its NOT necessarily true The efficiency of the stove depends on two factors #1) how hot you can get your firebox or secondary chamber and #2) how much heat transfer area is built into the stove. Now #1 can be argued that downdrafts are hotter, fine. BUT the bigger factor really is #2 for efficiency. You could have a clean burning downdraft stove with a crappy heat transfer area and it wouldn't be efficient at all! It will depend on the DESIGN of the heat transfer area of the stove, has nothing to really do with it being downdraft or not.

Are you coming from Arboristsite.com?


Me thinks you are.

 

[burnclean]

I have been on there yes, but only posted there a few times too. That forum has really nothing to do with my statement though...it just happens that I signed up there before here. I lurk on both...

 

[kabbott]

#2 is the easy part, and easily measured by stack temp.
#1 is not so simple. burning all the fuel before it goes through the heat exchanger is key.
I would agree that downdraft really means little other than the design is apparently easier with downdraft.
Gasification, Preheating and mixing proper air/fuel ratio seems to be the important part for complete combustion.
The Tarm,Eko, Econoburn and Garn among others seem to do a pretty good job of this. I see little evidence to argue otherwise.

 

[shoeboxlen]

The EKO idles pretty well by all reports, and even without storage a gasifier is way more efficient than conventional boilers. I ran mine wothout storage the first year and used 3.2 cords from mid-November to mid-March.

It does make a difference how you operate it. If you keep it burning 24/7, it will idle a lot more than if you let it go out between fires. A really good compromise is to load it up partway, let it burn to coals, and repeat. Gasifiers idling with coals aren't losing much. Idling with a full load of wood is a lot more wasteful.

I have done the same as no fossil however I still am running without storage. you wood consumption will go down as you learn how to feed your boiler. my eko 25 idles alot and I keep it going 24-7 I started burning early october this year. I have about 7-8 cords of wood to burn so i am hoping to last the winter. you will save wood if your idling alot by not filling the box up all the way. I throw in a couple good size logs and that will hole me in high 30 -low 50 degree weather about 6-7 hours depending on the domestic hot water tank.

 

[burnclean]

I agree #2 is the easy part, but not too many do that well...what are the stack temps (right after the boiler, not at the top of your chimney) you get with the EKO? I have looked at the EKO design for the heat exchanger and it looks like just the one tube...several tubes would be more efficient...or are there several? I don't see anything other than the statement on the EKO site that they are 91-94% efficient, which is totaly untrue. Its not mathematically possible atleast not using a high heating value its not. Stack temps have to be above 200 to not condense, just keeping those stack temps high enough will not allow you to have that high of efficiency based on the high heating value of wood.

BTW I'm not trying to start a war, just trying to spark some conversation that isn't so bias one way or the other

 

[shoeboxlen]

I am not sure what my stack temps are but mychimney does not get alot of creosote even though I idle alo my firebox on the other hand is loaded witht he stuff its like tar in there. so far no ill effects I just clean it as best i can in the summer months. I alos clean the chimney and pipe that goes to the builer in the summer as well. I added a t to my pipe to dump the fly ashe whil I am in operation as well. so far knock on wood we are very happy with our results.

 

[kabbott]

I agree #2 is the easy part, but not too many do that well...what are the stack temps (right after the boiler, not at the top of your chimney) you get with the EKO? I have looked at the EKO design for the heat exchanger and it looks like just the one tube...several tubes would be more efficient...or are there several? I don't see anything other than the statement on the EKO site that they are 91-94% efficient, which is totaly untrue. Its not mathematically possible atleast not using a high heating value its not. Stack temps have to be above 200 to not condense, just keeping those stack temps high enough will not allow you to have that high of efficiency based on the high heating value of wood.

BTW I'm not trying to start a war, just trying to spark some conversation that isn't so bias one way or the other

First I should state that i do not own one. I have however studied the design of several downdraft boilers because I am/was considering building
one. The EKO and others have multiple firetubes depending on the size of the boiler, some have two rows of tubes.

As far as the efficiency rating I believe it was stated somewhere that rating is taken at very high flow(water) at low temp. All of the ratings, no matter what
the make or model seem to stretch the facts a bit I will agree with you on that. I can't argue with "real world" numbers though and everyone I have
talked too about downdraft style gasifiers has had nothing but good reports on wood use and some have been able to make direct comparisons to non
gasification style boilers be it OWB or indoor and the difference in wood consumption is in most cases shocking.

Again I do not own one so I have no brand loyalty I just want the best for me. U.S. made would be a plus for sure and I am glad to see some U.S. built
competition

Others that do own an EKO may be able to answer your questions about the heat exchanger tubes more specifically

 

[Duetech]

Thanks for the replies everybody. I guess my main concern is; if I install the EKO 40 without storage tanks will it be an inefficient wood boiler? Is it useless to do it without the tanks? Or will it be alright? And on an other note, will this thing chug smoke real bad not being set up with the extra storage? I know these probably sound pretty stupid but I'm just trying to get a good idea of what to expect as the only experience I've had with burning wood has been in the fire pit in the back yard, the old Ben Franklin at the hunting camp and my parents basement wood stove from 30 years ago. Lol.

Hi Lar-Bud and a belated welcome to the forum. I am going into my fourth heating season with an EKO40 without storage for an "OLD" pre 1900's main structure with a 1945 add on home (when insulation was usually the clothes you wore). A full basement for the original structure and crawl space for the add on. Total usable footage is around 1750 sq. ft. Domestic hot water (side arm heat exchanger on a propane water heater) is icluded in my wood consumption.
Quality of wood is directly proportionate to the effectiveness of your unit. Wet wood is poor wood no matter what potential it may have when seasoned and produces way too much creosote. Seasoned wood: Lower btu woods will be less effective when you work with idle mode burning. Higher btu woods allow flexibility in your burning patterns. (http://chimneysweeponline.com/howood.htm)
In the winter my electric bill went up about $10 per month compared to prior years. My fuel oil went to -0-. A reasonable trade off. My propane went to $4 per month (for cooking) but -0- for hot water. I have a 20" sq exchanger in my oil furnace plenum. I have two circulator pumps on my system. With what I payed for the gas for my pilot light type gas water heater I now heat my home and heat my water. I am west of you in the state of MI and experience much of the same weather. I heat my dhw all summer long with partial/half loads where I turn the boiler off after a period of time and resume burning with a little wood added the next day. (repeat, repeat, repeat...etc.) I am probably running the most inefficient set-up because I don't have storage but for the year with medium woods (17-20 million btu's) I don't believe I go over 7 full cords (21 fc) and with higher quality seasoned wood it's less. I used to have a wood furnace and burned much more wood than I am now just for heat. Via scrounging and purchases my total wood costs since winter of 2006 are around $1200. One current wood source is 6 full cord for $750 of cut split and delivered oak and hickory which is less than my former annual propane bill. PM me if you have any more Q's for idle burn patterns.

 

[Gooserider]

I have been a lurker on this forum for quite a while before signing up today. I don't understand the obvious BIAS here on this forum towards EKO and downdraft gasifiers. I completely disagree that just because a stove is a downdraft it is going to be more efficient. Its NOT necessarily true The efficiency of the stove depends on two factors #1) how hot you can get your firebox or secondary chamber and #2) how much heat transfer area is built into the stove. Now #1 can be argued that downdrafts are hotter, fine. BUT the bigger factor really is #2 for efficiency. You could have a clean burning downdraft stove with a crappy heat transfer area and it wouldn't be efficient at all! It will depend on the DESIGN of the heat transfer area of the stove, has nothing to really do with it being downdraft or not.

I would say the alleged bias towards downdraft gasifiers is largely because this site, since it's founding has been interested in helping it's users get the cleanest burning, most efficient setups possible, whether it be wood stoves, furnaces, or boilers... This means both the least amount of crap out the stack, and the least amount of wood in the loading door for the amount of heat produced... We feel this way for many reasons - environmental, political (it isn't nice to gas your neighbors, it gets them peeved and makes them complain to the politicians that try to ruin all of our lives) and because we want to use the least amount of fuel we can....

Of all the various boiler designs out there, the two that seem to do the best jobs of clean and efficient burning are the downdraft gassers, and the Garn style units... Garns are essentially a class by themselves, and have lots of fans. There are lots of makes of downdraft boilers, which tend to be more alike than different IMHO, and of the ones that work, I don't think there is a lot of bias towards any particular brand - EKO gets mentioned more simply because they have a big market share, including some of our mods and more active posters... OTOH, if you go through all the threads that mention EKO, a pretty good chunk are involving percieved PROBLEMS with the units - which hardly is a great reccomendation by some standards....

However I would also say that in many of the threads where we talk about system setup issues, or other parts of it, I don't see any lack of willingness to help people that don't have EKOs or even downdraft boilers of any other sort, we help lots of folks with other styles of boiler, OWB's and you name it... In many cases, it almost doesn't matter what the heat source is - unless the question relates to actual boiler operation, a hydronic system doesn't know or care HOW the heat it is trying to distribute is produced - EKO, OWB, copper coil in the BBQ, it doesn't make any difference to the rest of the system, the answer to the problem will be exactly the same....

There are some problems that we have learned from experience tend to be associated with particular classes of units, such as inadequate piping with OWB's, but in many cases it isn't a problem with the OWB, but rather the not so clueful types that sell and install them... (Note that in such cases, the primary fix suggested is to improve the pipes, NOT replace the OWB with a gasser, as a gasser would perform just as badly in the same setup)

Bottom line, I feel that the site as a whole does it's best NOT to show bias, other than wanting stuff that works. If you were able to point us at an actual boiler that makes less smoke while burning less wood for a given amount of heat, than a downdraft gasser when used in a real world situation, burning a real world mix of firewood, then I'm sure we'd join you in promoting it, especially once we had a reasonable number of users confirming that it worked....

Gooserider

 

[sdrobertson]

I have looked at the EKO design for the heat exchanger and it looks like just the one tube...several tubes would be more efficient...or are there several?

My EKO heat exchanger consists of 16-two inch tubes that are 30" long (If I remember correctly).

 

[flyingcow]

Just skimmed this post. My tarm runs 400 degrees stack temp. If it starts creeping higher, it's time to give the tubes a scrub. Which is a bout every 2 weeks in the cold of winter.

 

[burnclean]

I have looked at the EKO design for the heat exchanger and it looks like just the one tube...several tubes would be more efficient...or are there several?

My EKO heat exchanger consists of 16-two inch tubes that are 30" long (If I remember correctly).

^Okay that makes better sense for efficiency claims :D

I think there was a new OWB recently announced that was cleaner than those gassifiers, now I gotta go find it...