Had another guy ask me about storage today

[heaterman]

As in "Why do I need it?" "The guy from brand x gasifier says their boiler will run just fine without it."

I don't have a lot of hope for this guy as I think he asked me after having already made up his mind and was just looking for some reinforcement. I pointed him to some of the European websites where the manufacturers stress what an important and integral pert storage plays in a wood burning system. I post this from Herlt's website but you can find similar admonition on practically any Euro manufacturer of wood boilers.

(You have to think a little bit due to the phraseology and translation from German to English but the message is there.) The italics are mine


Why do I need a big storage?


Oil- or gas boilers interrupt the feed of the fire material, when the programmed room temperature is reached. Wood gasifying is not that easy to stop. When the need is covered, the remaining energy will be diverted about the roof. (think dump zone) The stoker (homeowner) has to feed the boiler again, permanent work. (not desirable) To adapt the boiler power to the need, it is practical to reduce the revs per minute at the blower. Like this work HERLT boilers. The exhaust temperature will be programmed in relation to the quality of the chimney, lowest possible value by highest performance. (Chimney type and design dictate minimum flue temp) Because of this it is possible to achieve the best efficiency factor. What happens in case that the boiler power will be reduced because of a cutback of the fire? The exhaust temperature goes down under the minimum value, which is necessary to run the equipment in accordance with the regulations. (and the laws of physics) The consequences are expensive: tar, obstruction of the self-cleaning, chimney fire, poor exhaust values, a short boiler life etc. If the boiler would work with a low power, it would be very soon destroyed by acid, water and tar. Is it practical to buy a boiler, which can reach a efficiency factor of 91%, when it mostly only burns slowly with 25 %? ( Bullseye, Bingo, Nail on the Head) Use the comfort of a large storage for yourself and your boiler! Integrate a storage for a hot water requirement of 2-3 days, so your boiler can burn with optimal power and you can enjoy the breaks.

Once again I rest my case.

 

[leaddog]

I have to agree with you. I know that some people are getting by with out it but once they put it in they wonder why they didn;t before. I think the reason dealers and manufactures say they don't need storage is because it adds to the cost of the system. I know that storage is and can be VERY expensive but there is ways to keep the cost down. Same thing with the size required and exspence of insulation of storage. When I first started looking into gasifiers I could see that storage was very important and since then with my experience I believe that even owb would benifit for it. When my son asked 2years ago if storage would help his cb burn cleaner every one said that it would be a waste of time and money but I now think it would be a great benefit. An idleing boiler is wasting btu's and doing no good to the boiler or the air we breath.
Untill they make cordwood boiler modulate so they never idle storage IS required
leaddog

 

[in hot water]

I not sure how you define "big" storage. You should be able to size the storage very close to the needs of the building. While 1000 gallon may be fine for large BTU boilers and loads, an 18 or 25 KW boiler, driving a small load may be just fine with 300- 500 gallons.

Really, every job can and should be calculated and sized to the application and customers use patterns.

hr

 

[heaterman]

I not sure how you define "big" storage. You should be able to size the storage very close to the needs of the building. While 1000 gallon may be fine for large BTU boilers and loads, an 18 or 25 KW boiler, driving a small load may be just fine with 300- 500 gallons.

Really, every job can and should be calculated and sized to the application and customers use patterns.

hr

RE: "big storage" That quote is directly from Herlt's website. You'd have to go there and look at some of the pics of what they feel qualifies as "big".

You know HR........I think you once made the comment here or somewhere else........maybe the Wall, that the best place to store the btu is in the wood itself. I have to say that statement is absolutely true. The caveat is, a person has to live within the limitations of the fuel, which in the case of cord wood, makes storing the btu's in the fuel extremely difficult if not impossible to do while maintaining a clean efficient burn. That being said, size...as always.....does matter

 

[flyingcow]

Good posts, but I couldn't do without storage now. Once you storage, you never............? Fill in the blank.