Check my burn output numbers

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
Status
Not open for further replies.

goosegunner

Minister of Fire
Oct 15, 2009
1,469
WI
Does this seem like low output or normal

Econoburn 200
Total system 1075 gallons

8955 btus for 1 degree rise

I did a 3 hour burn which consumed 91 bounds of red oak.

Start temps were
Boiler 105
Tank top 144
Bottom 129

So I will use a average tank temp of 136.5

Finished temps
Tank top 179.8
Bottom 178


It was warm today so I will use 30,000 to heat load over the three hours plus 380,588 btus to raise tank 42.5 degrees for a total of 410,588 btus.

Divide 410,588 by 91 lbs of wood = 4,512 btus gained per pound of red oak.

Does this seem in line or low?

Seems to be about 75% efficiency.

gg
 
To arrive at the approximate 75%, you're probably using the typical 6190 btu/lb for red oak from the charts. But that number requires 20% MC. Did you resplit a few of your oak splits and test with a MM? Oak is notorious for being well over 20%, sometimes even after a couple years of good seasoning. The further over 20 your oak is, the worse the efficiency appears to be.
 
Looks like you averaged 135K BTU over 3 hours, not too shabby. Your boiler rating is for peak, the three hour average includes start and burn down, not 3 hours of peak. I'd take it any day.
 
Hunderliggur said:
Looks like you averaged 135K BTU over 3 hours, not too shabby. Your boiler rating is for peak, the three hour average includes start and burn down, not 3 hours of peak. I'd take it any day.

I guess it's not bad considering start up and coast down, but it is a 200,000 btu boiler.

gg
 
willworkforwood said:
To arrive at the approximate 75%, you're probably using the typical 6190 btu/lb for red oak from the charts. But that number requires 20% MC. Did you resplit a few of your oak splits and test with a MM? Oak is notorious for being well over 20%, sometimes even after a couple years of good seasoning. The further over 20 your oak is, the worse the efficiency appears to be.

I used 6050 a lb as the baseline.

I resplits my wood small and it sits in boiler room for 5-6 days before burning. My moisture meter wont read some pieces, some about 15-20.

gg
 
Do you know your water flow in GPM?

Boiler output Q = dT x Flow x 496

496 for water
475 for water glycol

Your flow in the boiler loop should be more or less the same all the time, unless you have a variable speed pump.
You can measure de delta T at the in and out of the boiler.
Do this during steady state operation for 1 hour and you will know how much it is cranking out in BTU/hr

I would measure the dT every 1 minute and write them down
Or you can automate it with some 2 USB temperature data loggers; 1 on the in and 1 on the output of the boiler (return/supply)

Then you calculate Q for every minute measurement and divide it by 60 (because you measure every minute)
You do this 60 times and add them all up
This will give you your boiler output for that specific timeframe

The Econoburn is on the list of EPA.
So the numbers you see there are obtained by using the EPA hydronic heater testing protocol: http://www.epa.gov/burnwise/pdfs/owhhphase2agreement.pdf
HHV – Higher Heating Value of fuel = 8600 Btu/lb (19.990 MJ/kg) LHV – Lower
Heating Value of fuel = 7988 Btu/lb (18.567 MJ/kg).
This testing protocol allows some manufacturers to achieve 99%. LOL
 
It was warm today so I will use 30,000 to heat load over the three hours plus 380,588 btus to raise tank 42.5 degrees for a total of 410,588 btus.

Divide 410,588 by 91 lbs of wood = 4,512 btus gained per pound of red oak.
Does this seem in line or low?
Seems to be about 75% efficiency.

6050 btu/lb available is quite accurate at 20% MC and 400F stack temperature. Based on your assumptions, your calculation is good. If your heat load was a little higher, then your efficiency calc would go up. A better test would be to shut your load down and repeat the test. Overall your efficiency certainly is in the range of expectations.

I like the way you did your test because it measures what was actually delivered in a usable form to your system. Measuring output at the boiler would more accurately determine boiler efficiency, but delivery of usable btu's to your system is what counts IMO.
 
Heat load overnight was 170000 btus for 10 hours.

I put in a 60lb load this morning before leaving for work. It should have raised my tank to 185 top to bottom.

Start temps 5 am

Boiler 140
Tank top 168
Bottom 151



60 lbs wood, 1 hour 45 minutes on the timer

My wife checked temps at 830 am and found

Top 179
Bottom 175

A 17.5 degree rise in tank or 156,712 btus + 59,550 to heat load =216262 btus

216262 btus / 60 lbs of wood = 3604 btus per lb gained or not too good.

Not being home I do not know if load burned completely with time allowed. Or if the nozzle was covered. I have noticed that if the nozzle becomes uncovered the output suffers. To max output I really need to stir towards the end of burn.

gg
 
Attached is a page of similar calculations I made on my effecta lambda 35 boiler last winter.

There are now several effecta lambda 35/60 boiler users in my area and thus we compare performance of our boilers quite often.

All of us are very pleased with the performance of our effecta lambda boilers and are getting very similar results.

By comparing your results to the results on the attached page you should get a good feeling for how your boiler is performing.

Thanks,

Brian
 

Attachments

  • effecta lambda efficiency study1.jpg
    effecta lambda efficiency study1.jpg
    146.9 KB · Views: 332
Effecta Boiler User said:
Attached is a page of similar calculations I made on my effecta lambda 35 boiler last winter.

There are now several effecta lambda 35/60 boiler users in my area and thus we compare performance of our boilers quite often.

All of us are very pleased with the performance of our effecta lambda boilers and are getting very similar results.

By comparing your results to the results on the attached page you should get a good feeling for how your boiler is performing.

Thanks,

Brian

How did you determine the loss of your tank?

It does add up pretty fast if you look at tank loss over 24 hour period.

gg
 
I also need to insulate my big copper lines in the boiler room. I have about 40' of 1-1/2" that is uncovered and about 40' of 1-1/4" that goes to my load that is uncovered.

gg
 
Effecta/Brian - I do not at this time doubt the ability of a gasification boiler to deliver 87.5% efficiency as measured by btu input and btu output. But both of these can be and are huge variables. These can be established in the laboratory subject to strict measurements and at considerable difficulty. To establish them in the field suggests an enormous task of measurement. To provide added validity to your report, we really need to see the background data establishing hard maple at 22% MC having 6250 btu/lb energy available. Similarly, we need to see the background data establishing the house and tank heat loss. I assume you have these available, since you use these to calculate the Effecta efficiency. Might we see this data? Thanks.
 
Jim,

Thanks for raising the questions.

Yes, I took as much care and attention to detail in perfroming these tests that I humanly could. However, I am not a high tech/high end/high dollar test lab and thus am not saying my results are without error.

Being a mechanical engineer I was taught to always get data before establishing an opinion/publishing data and thus this is how I operate 100% of the time.

I would like to know from you (and others) what criteria everyone would like to see when undergoing an engineering study of this type.

Here is the assumptions I made and the equipment I used when performing this study last winter:

1.) The wood moisture content was measured with a Lignomat model #mini LIGNO XL/C wood moisture meter.
2.) The weight of the wood was measured using a Health o Meter model# HDM560DQN-01 scale (I held an armful of wood and then subtracted my body weight from the total weight outputed by the scale).
3.) The heatloss of my home was established by measuring the actual drop in temperature (over a period of 10 hours on a cloudly day) of the water in my tanks (2 x 500 gallon propane tanks) when the outside temp. was 30F (+/- 3 F). I use Azel digital temp gages and have probes at the top of top tank, bottom of top tank, top of bottom tank and bottom of bottom tank. The drop in temp was then plugged into the typical formula of (delta T x 1000 gallons x 8.33) and a total heatloss was calculated. I then divided this heatloss by 10 hours to get a per hour heat loss.
4.) The heatloss of the tanks was established by measuring the actual drop in temperature (over a period of 10 hours) of the water in my tanks (2 x 500 gallon propane tanks) with my homes heating system being turned off (not pulling any water/BTU from the tanks).
5.) The BTU value for the wood was taken from a chart published by the Michigan State University. If there is one area of differencing opinion by various government agencies and individuals it is this. There are many different variables that go into this value. I am definately open to suggestions to get this value the most accurate.

Last year was the first year I owned/operate my effecta lambda 35 boiler. In addition, this year I have much better wood (15-18%) moisture content hard maple and beech and thus would like to perform a similar study.

However, before undergoing this task, I am asking for everyones engineering based suggestions for ensuring we get the most accurate results.

Thus, I will wait a week or so and let everyone post their suggestions before performing the new study.

Thanks,

Brian
 
Not questioning what's being posted in this thread, but just in the interest of full disclosure, Effecta Boiler User is also Effecta Boiler Dealer, correct?
 
Yes, that is true.

However, I am being very careful about the information/advice I post on hearth.com because it is my full intent to help other Hearth.com members with their questions/problems etc in a 100% technical, data based manner.

Also, I fully understand the rules and regulations on hearth.com regarding commercial use.

I am a mechanical engineer and have a full array of data logging equipment for both electrical and temperature datalogging and thus I am always performing testing on my effecta lambda 35 boiler and enjoy sharing it with others

One thing I do not see on Hearth.com very often is real life test data and thus I am trying to supply this data.

One thing I do see on hearth.com is a lot of opinions without data to back it up and I am also trying to change this also.

Thanks,

Brian
 
Effecta Boiler User said:
Yes, that is true.
However, I am being very careful about the information/advice I post on hearth.com because it is my full intent to help other Hearth.com members with their questions/problems etc in a 100% technical, data based manner.
Also, I fully understand the rules and regulations on hearth.com regarding commercial use.
I am a mechanical engineer and have a full array of data logging equipment for both electrical and temperature datalogging and thus I am always performing testing on my effecta lambda 35 boiler and enjoy sharing it with others
One thing I do not see on Hearth.com very often is real life test data and thus I am trying to supply this data.
One thing I do see on hearth.com is a lot of opinions without data to back it up and I am also trying to change this also.
Thanks,
Brian
Four years ago, while in the process of trying to get back into heating with wood after an extended absence, I found this forum. I didn't know a gasifer from a hole-in-the-wall, and Hearth almost certainly saved me from having a wood-gulping, smoke-belching monster sitting in my yard. I read lots of threads, and found out just about everything I needed to know in order to make the decision that was correct for me. One of the keys in all of that was that dealer-hype was not a part of it. It was real people describing their experiences with their own boiler - good, bad, and in some cases ugly. I had Greenwood/Seaton on my list, but fairly quickly crossed those out, based on the feedback from the owners of those boilers. I'm sure that if Fred Seaton was posting, he would have said that all of these folks with problems were operating their boiler incorrectly - he would have had the answer for all of their issues. This is not a commentary on the validity of your information or the quality of your boilers. The point I'm making is that you have an automatic, built-in bias toward your product. And anyone reading your information needs to be aware of that, and factor it in. I'm generally very pleased with my Econoburn - no significant problems, the oilman is gone, replaced by a reasonable amount of wood. But it has a few things that could be improved - and I (and other owners) have described those things in detail here. There's no outside bias in our feedback. So post away, just let's be sure everyone knows where you're coming from.
 
Effecta, I like you seek to determine real world operating data rather than relying on laboratory reports. A homeowner cannot duplicate the laboratory. I will give more thought to your methodology, but at first glance it is reasonable. And I agree that determining actual available energy from wood is a tough nut to crack. I use 6050 btu/lb at assumed 20% MC and assumed stack temperature of 400F. Energy in Wood

I went back and checked the efficiency calculation for my Tarm Solo 40. This is measured under the above assumptions and heating the tank only, with mixing to assure a uniform tank temperature. It does not account for tank loss through the insulation during the charge period. The Tarm delivers just about 85% under these assumptions. In daily operations I use assumed 80% because during a burn period my shop usually has a draw on the system, which typically amounts to about 80,000 btu's, and use of 80% means about another 17 lbs of wood during a burn period.

Thanks for the info.
 
Effecta Boiler User said:
Jim,

Thanks for raising the questions.

Yes, I took as much care and attention to detail in perfroming these tests that I humanly could. However, I am not a high tech/high end/high dollar test lab and thus am not saying my results are without error.

Being a mechanical engineer I was taught to always get data before establishing an opinion/publishing data and thus this is how I operate 100% of the time.

I would like to know from you (and others) what criteria everyone would like to see when undergoing an engineering study of this type.

Here is the assumptions I made and the equipment I used when performing this study last winter:

1.) The wood moisture content was measured with a Lignomat model #mini LIGNO XL/C wood moisture meter.
2.) The weight of the wood was measured using a Health o Meter model# HDM560DQN-01 scale (I held an armful of wood and then subtracted my body weight from the total weight outputed by the scale).
3.) The heatloss of my home was established by measuring the actual drop in temperature (over a period of 10 hours on a cloudly day) of the water in my tanks (2 x 500 gallon propane tanks) when the outside temp. was 30F (+/- 3 F). I use Azel digital temp gages and have probes at the top of top tank, bottom of top tank, top of bottom tank and bottom of bottom tank. The drop in temp was then plugged into the typical formula of (delta T x 1000 gallons x 8.33) and a total heatloss was calculated. I then divided this heatloss by 10 hours to get a per hour heat loss.
4.) The heatloss of the tanks was established by measuring the actual drop in temperature (over a period of 10 hours) of the water in my tanks (2 x 500 gallon propane tanks) with my homes heating system being turned off (not pulling any water/BTU from the tanks).
5.) The BTU value for the wood was taken from a chart published by the Michigan State University. If there is one area of differencing opinion by various government agencies and individuals it is this. There are many different variables that go into this value. I am definately open to suggestions to get this value the most accurate.

Last year was the first year I owned/operate my effecta lambda 35 boiler. In addition, this year I have much better wood (15-18%) moisture content hard maple and beech and thus would like to perform a similar study.

However, before undergoing this task, I am asking for everyones engineering based suggestions for ensuring we get the most accurate results.

Thus, I will wait a week or so and let everyone post their suggestions before performing the new study.

Thanks,

Brian



Ok this won't change your numbers much but if you used drop in tank temp to calculate your homes heat loss would not the loss from the tank be in that drop also?

I do not think you can add in the tank loss from your formula unless you subtract it from your load loss right?

gg
 
Status
Not open for further replies.