EconoBurn Factory Tour

[chrishh]

Hello all,

I just got back from a factory tour of the alternativefuel gasification boilers facility in Brocton NY. Spoke with both Dale and Mark and can't say enough with how pleased I was with their hospitality. They took me through the process from start to finish and showed me all the steps of testing that where involved. Because of this and other factors I have decided on my gasification boiler.

I have a few questions when trying to size thermal storage for the system. The guys at EconoBurn had a thermal storage system from STSS. They also had their systems sized to their boilers. EWB-100 = 620 Gallon Tank, EWB-150 = 822 Gal., EWB-200 = 957 Gal, and EWB-300 = 1550 Gal. Which sounds like I have my answer, however I would think that this would also depend on how long you wanted to go without doing another burn? This is where I start to get confused. I had a heat loss/gain calc done on the house it came out to 68000BTUh, I was told the EWB-100 should be good for that load. So if the EWB puts out 100,000 BTUh and I store that 100,000 BTU's doesn't that mean it would be gone in just under 2 hours? I'm trying to size a system to run on one burn a day. So it would have to run for 24 hours on the thermal storage. Pluse I plan on using DHW on top of the 68000 btu load. Any help understanding this would be greatly appreciated.

Thanks,



Chris

 

[Floydian]

A factory tour would be fun.

I would think (I'm no pro) an EBW-100 would heat your house+DHW, its just going to be firing a lot. With enough storage to keep it from idling, it should be very efficient.

What is the lowest water temp your system can use?

If one firing a day is a big priority to you, your looking at some serious storage at 68K btu/hr x 24=1,632,000 btus. Assuming you can utilize water from 180* down 110* (70* delta T) you would need 2800 gallons. You probably would not need 68k for all 24 hours in a day, but thats not taking DHW into account. Maybe at design temp your looking a couple of firings a day, but still a lot of storage.

I believe the STSS liners don't like temps above 175*.And 170* might be better in the long run but I'm not sure.

I personally think the Garn stands out when dealing large amounts of storage. Being able to recharge your tanks at 350K+ btu/hr would sure make a big difference. Of course the Garn can add significant $ to a project if you don't already have a building to put it in.

Good luck,
Noah

 

[Piker]

If you use a smaller delta T you can get to where you would only have to fire the boiler twice per day with an EBW100 and 620 gallons of storage.

620 gallons @ 50* delta T will store about 250k Btu's. At design temp, your boiler will have 32k Btu's to spare and will take about 8 hours to charge the tanks and supply the load to the house. You will probably burn two full loads in the boiler. After that, your storage can heat the house for about 4 more hours for a 12 hour cycle. Not bad. The only issue is if you aren't around for 4 hours in the morning to fill the boiler the second time on your 8 hour burn you might come up short in the afternoon on heat.

cheers

 

[chrishh]

Thanks for the info.

To give some more info I am planning on using in floor radiant heat, stapled up under sub floor, tile and hard wood on first floor and carpet on second. Whith this info what would the Delta T? be for a typical system like this. Also how did you guys come up with the storage numbers? I would like to know how to calculate this myself so I can see if it would be beneficial to go to say a EWB-150. Also I'm a little confused when they say the EWB-100 is 100,000 BTUh. Am I understanding that the unit will put out 100,000 BTU's per hour of use. And if so how long do burns normally run on the 100 and for the EWB-150 how long do those burns run? I would think that this would have a grate impact then just the size. if I have a heat load of 68k btuh that's at the maximum temperature of -6 F for my area and heat set point of 70 F but this isn't going to be like that all day and not all season aether. I looked up on the web and found for my area the average temperature for the winter season is 26.3F would it be better to use that number to figure the loads?

Sorry for so much questions I'm just really not sure how to size this correctly, I keep reading and I think I'm getting more confused than when I started.

Oh by the way Piker you where mentioned by Mark at EconoBurn on the tour. If you are the dealer in PA?

Thanks,



Chris

 

[Floydian]

Number of gallons x 8.33=Btus per dergree change. So 620 gallons x 8.33=5165 btu/degree. Multiply that by your delta t and you have stored btus. So 5165 x 50*=258,250 stored btus. I don't know temps for staple up-120*+? Surely higher under carpet.

If your 68K btus/hr is based on a decent heat loss calculation, thats the number I'd go with over avg. winter temperature. I have played around with a couple of free online calculators and the thing that stood out the most to me was windows. Decent window treatments that could add R-5 to an R-3 or so window would knock down that 68k number a bit. Insulated blinds or such. A good investment if the rest of the house in good shape.

I like the idea of pressurized storage. Higher temps and no HXs in the heating system. I am hoping to go the used propane tank route but this is not an option in a lot of basement situations. And the STSS or homemade route certainly work well too.

Noah

 

[chrishh]

ok so I think the only bit of info left that I need to figure out is how long does the EBW-100 and the EBW-150 run for? Please correct me if I'm wrong but if I have an EBW-100 and it runs for say 4 hours on a single load of wood then wouldn't that mean that I pumped out 400,000 btu's and if I take the same burn time and apply it to the 150 that would mean that I would pump out 600,000 btu? then I would have to subtract the load at the time of charging 68,000 btu from each hour. so that would leave me with for the EBW-100 running for 4 hours with 128,000 btus in storage? which would only last me like 2 hours at 68k btu????

Thanks,



Chris

 

[pybyr]

ok so I think the only bit of info left that I need to figure out is how long does the EBW-100 and the EBW-150 run for? Please correct me if I'm wrong but if I have an EBW-100 and it runs for say 4 hours on a single load of wood then wouldn't that mean that I pumped out 400,000 btu's and if I take the same burn time and apply it to the 150 that would mean that I would pump out 600,000 btu? then I would have to subtract the load at the time of charging 68,000 btu from each hour. so that would leave me with for the EBW-100 running for 4 hours with 128,000 btus in storage? which would only last me like 2 hours at 68k btu????

Thanks,

Chris

Unlike a fossil-fueled heat appliance (oil, gas)... none of the wood units are able to go from 0% to 100% BTU output right away, or, for that matter, to go back from 100% to 0%. And output will vary with size and type of wood and how dry it is.

So... running a 100 k BTU unit for 4 hours will not necessarily get you 400,000 BTUs. There's the ramp-up of getting the fire going, and then the ramp-down as the fire dies down.

My Econoburn 150, with good dry wood, and a good batch of kindling, and the right finesse for light-off, will heat my big old VT farmhouse way faster than my 125,000 BTU oil burner (which is a quality make). But, try it with marginally dry wood, or a hurried light-off, and, well, it's an uphill battle instead.

I am NOT trying to besmirch my Econoburn, or gasifiers or wood appliances in general--- just trying to point out that the 'nameplate' BTU rating is more complex than with a gas or oil burner that you can instantaneously switch on and then off.

Over-sizing heating appliances is generally a bad thing for efficiency. But, with the above variables for wood boilers, and if you plan on sizeable storage, erring on the side of abundance may not be a bad idea

 

[Piker]

basically, if you are going to install thermal storage you don't need to worry about burn times... the first thing you need to do is figure out how long you want to go between firings at your design temps... then size the storage and boiler accordingly. The scenario I posted above would be an extremely efficient setup... but like I said, you might struggle with your time frame for getting that second load into the boiler in the morning (again, at design temp). That having been said, when temps rise above design, things will get progressively easier concerning that time frame.

Just be aware that because the output of these boilers is not static, the math involved in calculating boiler and storage size can be a little fuzzy, but basically you still have to run the numbers like you would any other system. If the numbers show that you're on the edge of what looks practical then bumping up one size boiler and adding a little more storage isn't going to hurt.

cheers