Why storage????

[leeeallen]

I have an Eclassic 2300 and a Peerless oil boiler. I have an 80 gallon Superstor storage tank because I have a large demand for hot water (old farm house with 2 apts. in house plus my living space) My present system is and has worked fine - but I have read that some people have 500 - 1000 gallons of storage - Can someone explain the advantage of having that much storage ???????

 

[jebatty]

There are a great many posts on the "why" of storage. Do a search and see if your question is answered.

 

[leeeallen]

I have read some great posts on designs, but have not been able to find a good explanation on the WHY?

 

[stee6043]

Two reasons - convenience of when you burn your fire and efficiency. A wood burner burning full-out with no idling burns much more effieciently than a wood burner that idles. That means you use less wood. And when you store significant amounts of heat in tanks you can heat from those tanks during periods when you don't want to have a fire.

I personally start a fire at 5pm on a normal winter day which dies out by midnight. This is all the fire I need to heat 3,200 square feet at 70 degrees. I couldn't do that without storage. The boiler would have to run all day.

 

[kabbott]

I second the reasons listed above.....And will add that that it is just great for shoulder seasons.
With the weather we have had the last week or so....65 during the day and 30's at night I still need heat but with no storage you get one of
two things, a smoldering fire or so hot your opening windows. I have 13,000 Lbs. of hot water in the basement and can go for 2,3 sometimes 4 days
with no fire with this weather. Plus when the BOSS says SHE IS COLD I just go turn up the stat a little. Makes for a happy home...

I would not go back to no storage even if it did not help efficiency...no way.

 

[leeeallen]

This is a reply I got from a forum member - does anyone have an answer that might guide me in the right direction?


I'm not sure how I would suggest running storage with an outdoor unit.
The problem you have is that you cannot let your boiler burn-out due to the
risk of freezing. Those of us with indoor units with storage let the fire
die every day and restart every day. That's how you avoid idle.

Most folks consider 1000 gallons to be a minimum for storage for a
standard size home/heat load. You have an e-classic, correct? I think 500
would be undersized with the amount of heat you can create.

I'd post some more on hearth.com. I'm really not sure how you're going to
be able to achieve the efficiency we see with indoor units. I only run my
boiler 7-8 hours per day max. The rest of the time it sits empty/not
burning. If you run your boiler like this you'll probably freeze it. One
possible solution is to run hot water through it constantly even if it's not
running. But this is wasted heat and electricity. Not to mention that you
have to go outside to restart fires, which may or may not be a pain....

 

[Rory]

Another good answer to your original question involves domestic hot water. I have a 670 gallon tank, and I supplied my wife and I with hot water all summer on about 1 fire a week.

 

[flyingcow]

This is a reply I got from a forum member - does anyone have an answer that might guide me in the right direction?


I'm not sure how I would suggest running storage with an outdoor unit.
The problem you have is that you cannot let your boiler burn-out due to the
risk of freezing. Those of us with indoor units with storage let the fire
die every day and restart every day. That's how you avoid idle.

Most folks consider 1000 gallons to be a minimum for storage for a
standard size home/heat load. You have an e-classic, correct? I think 500
would be undersized with the amount of heat you can create.

I'd post some more on hearth.com. I'm really not sure how you're going to
be able to achieve the efficiency we see with indoor units. I only run my
boiler 7-8 hours per day max. The rest of the time it sits empty/not
burning. If you run your boiler like this you'll probably freeze it. One
possible solution is to run hot water through it constantly even if it's not
running. But this is wasted heat and electricity. Not to mention that you
have to go outside to restart fires, which may or may not be a pain....

well said, but I wonder about putting glycol in the eclassic. Might work. It would keep the unit from freeze up(how long would it take to heat the water jacket up in order to circulate to heat up the storage??). I wouldn't worry about freeze up in most winter months. The few weeks of jan i would be concerned. As mentioned. with storage you'll be lighting a fire every day or so. Not a problem once you get used to it, but..........what little i know, doesn't seem it would be worth the extra $$$$'s

 

[stee6043]

Keep in mind glycol will reduce your overall system efficiency (significantly??). So if you're trying to reduce wood consumption with storage you may be offsetting those gains by adding glycol......perhaps....

 

[Gooserider]

Keep in mind glycol will reduce your overall system efficiency (significantly??). So if you're trying to reduce wood consumption with storage you may be offsetting those gains by adding glycol......perhaps....

Glycol does make for lowered heat capacity, and less efficient operation to some degree, but wouldn't really be a big issue in this hypothetical case... Presumably it would mean needing to have a higher flow rate, and circulate the fluid between the boiler and the storage tank faster, which might require a larger pump / bigger piping for that circuit, but not hugely so... You wouldn't need (or want) glycol in the storage, and probably not in the storage - house circuit.

As to the boiler freezing, I don't know. I'd think it would depend a fair bit on how well insulated the boiler outhouse is, but if the building has reasonable insulation, and all the lines are run with good insulation and / or below the frost line, I would be kind of surprised to learn that the boiler would lose enough heat to freeze in the length of time it would take to draw down a reasonably sized storage tank... If it did, glycol would probably be all that was needed to protect it, or possibly just have a SMALL pump that would circulate water from storage back through the boiler as needed (probably cheaper than glycol... remember you don't need to keep the boiler hot, just above 32*F, so I'd expect a really small pump would do the job just fine)

Gooserider

 

[leeeallen]

I have 350 gallons of water in the Eclassic , plus the 250 ft of run to house - that's alot of glycol to prevent freeze up - pretty expensive.

 

[Gooserider]

I have 350 gallons of water in the Eclassic , plus the 250 ft of run to house - that's alot of glycol to prevent freeze up - pretty expensive.

That is why I was saying I don't know that you'd need to do glycol - How well is the outside of the boiler insulated? How well insulated are your lines? Are the lines below the frost-line depth, or at least close to it? It would seem to me that it would take at least a couple of days of seriously cold weather to cool a boiler with 350 gallons of hot water in it down to freezing - far longer than you would be going between fires...

I would also say that while we have had LOTS of people put storage with conventional style gassers, with almost universally great results, I don't recall a lot of people doing storage with OWB units, so I don't know if the benefits would be as great...

Gooserider