Please brag about your storage

[Nofossil]

All good points, but I'll stand by the issue of intervening heat exchangers. Anyone who has attempted to 'top off' an unpressurized tank (yours truly, for one) can attest to the problem of the last 10 degrees.

The heat transfer rate of a heat exchanger depends on the difference in heat between the two fluids. When storage is cold it's no problem to dump the full output of the boiler through the heat exchanger into storage. As storage heats up, the maximum possible heat transfer rate drops. At some point it's less than the boiler's output and the boiler will start to idle. As the storage gets closer to the boiler outlet temp, it becomes increasingly hard to transfer much at all.

If you have an immersed tubing HX (like mine) the hot water near the top of storage becomes less able to remove heat long before the top of storage reaches boiler outlet temp. As this happens, hotter water gets farther down the coil and starts heating the middle and then the bottom of the tank. This diminishes stratification. More feet of coil and/or lower flow rates reduce this effect.

A properly designed pressurized system on the other hand can maintain a sharp thermocline between the hot (boiler outlet temp) water at the top and the cold water at the bottom. The boiler sees cold water for almost the entire volume of storage, and all of storage is brought right to boiler outlet temp.

 

[tom in maine]

I agree, NOFO, that the heat exchanger can be a bottleneck, while charging the tank, which was your original point.
A better heat exchanger will minimize this.

OR, you can pump unpressurized tank water through the boiler into the tank.
I do this and have done it for many years with both ferrous boilers and non-ferrous boilers.
It can save on cost and work well. I am not sure about a manufacturer's view on this.

You do deal with noise and potential corrosion if the boiler is not fully wetted with treated water.

 

[Piker]

How long of a burn to get that 1000 gallons of storage up to temp Piker?

It depends. The boiler can go through a load of wood in 5 hours (give or take obviously depending on fuel) providing it can run at full output. What happens on my system though, is that as the return water begins to rise in temperature, the boiler will reduce output to match load. With less delta t between the tanks and boiler, you either have to increase flow substantially or decrease output substantially to prevent running the boiler in an overheated state. I preferred to use the loading unit with integrated termovar as opposed to a bigger circulator and thermostatic mixing valve, therfore my boiler will run a little longer in the reduced output state... say 6 hours or more total on a typical run on storage.

The Froling seems to have plenty of muscle to charge the tanks quickly, and really seems to toy with the 1000 gallons I currently have. I could easily add another 500 gallons to the system, though I don't know where I would put it. The nice thing about it is, the Froling mixes muscle with finesse to glean the best efficiency out of the system.

I should also note that my tanks are horizontal... and I don't get the best stratification. On top of that, I have witnessed what appears to be a "current" through the tank, leaving some cooler water untouched in the tanks while returning slightly warmer water to the boiler than what the bottom tank sensor is reading. It eventually all stabilizes towards the end of the burn, but it can push the boiler into the lower output stages a little earlier than would be necessary if you could get that cooler water back to the boiler.

The bottom line is, there's no need to force the storage up to temperature with brute strength... not when you can modulate output to match demand. In all reality, your firewood is as good a place as any to store your Btu's providing you can maintain efficient combustion... which the control on the Froling affords down to 50% of the rated output.

cheers

 

[flyingcow]

First......loggie, less coffee. generally speaking, people on this site are good, and spot on in their experiences. If you haven't been here long try not calling 'em liars, unless you follow their posts for a period of time, then call 'em out. But this site has really been a great way to learn about how to burn wood, EVEN IF YOU"VE DONE IT BEFORE. Sorry, i shouldn't be feeding your fire, loggie, but sit back an read and soak up the good company.

Now, I have an unpressurized storage. Bought it from "Tom In Maine". A couple of reasons why. first, i have listened to him on his weekend radio show, which is called "Hot and Cold" giving general advice on everything related to whatever to living in Maine. Building construction, cement, pests, solar heat, wood heat, etc. Good flat out good advice. But he's done thermal storage tanks(for at least 30yrs?), mainly at first for solar, but morffed into wood boilers. I liked his designs on the physical structure of the tanks. And he's worked for yrs with Professor Dick Hill. Hence his HX's, for the tanks. this isn't 180 ft of copper coiled into a tank. I don't have too much of a problem driving my tank to 180. Only do it in the winter. In the summer, only push it to about 165. this will give me close to 5 days of DHW. Thats with kids in teens.

But, what to heck.....i have an 1800sq/ft, 2 story house(plus basement), moderate insulation, on top of a very windy hill, in northern maine, we are keeping the house at a very warm 70+ in the deep of winter, on no morethan 7 cord. AND I KNOW HOW TO MEASURE A CORD OF WOOD. Call me i liar.........put out the cash. Sorry moderators....welcome back Goose

 

[MarkJ]

Speaking of storage I've got a line on a nice used 500 gal propane tank. Not sure how I'll put it in the basement yet but I'll be here with a few questions for the gurus if it happens. And I should know by the end of the week. I never thought I'd be excited by the idea of buying an old propane tank.

 

[Birdman]

MarkJ. Please keep us posted on your experience. I would love to follow your progress as I am hoping to do the same thing. I am really looking for a step by step process.

 

[MarkJ]

MarkJ. Please keep us posted on your experience. I would love to follow your progress as I am hoping to do the same thing. I am really looking for a step by step process.

Absolutely!

 

[benjamin]

I can't wait to heat my house by rolling up the Sunday paper and a hand full of Popsicle sticks for my once a week fire.I will stack my Popsicle sticks on a east to west direction to get southern exposure so they are properly dry. I really feel gulty about killing all those trees every year to feed my old wood waster.Can anyone recommend a dealer where I can buy one of these newfangled Wonderboiler....... I can't wait.

Since everyone respects Nofossil, I'll assume this contempt was intended for me so maybe I'll just go back over to thebumb.com, I go by DecaMom.

Nah, this is too fun.

First of all the popsicle sticks must be properly aged first and then dried, and you just might want to think about air sealing, then maybe even insulation too. The best model of the Wonderboiler claims only 85%, so if you're burning right even in an old barrel you're only going to burn about one third less wood for your well spent Wondermoney. To get your wood consumption down to the Sunday paper, you will need to seriously look at your heat loss.

I think we all know people who spend $5-10k on an OWB and spend their winter feeding the beast. Heck, I met some city folks last fall who just bought a big ol house where the OWB had been taken out because it COULDN'T heat the place, and were planning to use a small airtight stove instead, haven't heard if they made it or not. I also know one guy who parks his truck and trailer next to the OWB, piles the wood and throws it right in, this is fairly easy because his truck has one of those Prentice thingies on it.

Some of the fanatics on here have spent a lot of time figuring out a system that works for them, some have taken the time to share their experience and that's what the rest of us find so valuable about this site. I enjoy seeing what others have tried even if I think it's a hairbrained and I would never do it that way myself.

Some of these systems make it extremely easy to get a huge amount of heat with the least wood possible. I don't know if anyone has claimed they make it easy to heat the impossible, but they sure are better than many of the alternatives such as: being a slave to a woodburner, buying a log truck to go with your OWB, or sleeping on a rotisserie two feet from a red hot stove.

If you look into the new houses that are being built to be energy efficient, some of the extreme ones use so little energy that they can't economically justify a furnace at all, the additional investment over electric baseboards just won't pay off. Anybody considering spending the amount of money (and time) involved in these systems ought to look at their heat load and whether the resources would be better invested in efficiency of the load in addition to the source.

But hey, if you like to burn 20 cords a year, we want you to burn 20 cords a year.

 

[Nofossil]

Anyone who ever saw the pitiful Sunday paper here would know that it's not a viable heat source ;-)

I've gotten pretty thick skin over the years. I've hosted many visits from forum members and others, all of whom can attest to my setup and the operation of it. I figure that I'll share all my techniques and all the hard data that I can provide (and that's been a LOT over the years). There are several outcomes I can think of:

1) Someone else will have a better idea and / or improvement. I'll learn something. That's a win.

2) Someone else will use my ideas and get a better outcome than they would have otherwise. That's a win, too.

3) Someone else will try something that doesn't work as well and I'll know not to bother trying it. Another win.

4) None of the above, but some humor can be extracted from the experience. I'll also count that as a win.

Four outcomes, all winners. Doesn't get much better than that.

 

[DaveBP]

I have found over the years that popsicle sticks aren't all they are cracked up to be. I just can't get a full night of heat on a mid-winter night out of even two hands full. I've gone over to tongue depressors for the long cold spells. Now THEY pack some BTUs let me tell ya'.

 

[mole]

I have found over the years that popsicle sticks aren't all they are cracked up to be. I just can't get a full night of heat on a mid-winter night out of even two hands full. I've gone over to tongue depressors for the long cold spells. Now THEY pack some BTUs let me tell ya'.

The problem with popsicle sticks is that by the time I've eaten enough popsicles to make a little heat, I'm frozen. My wife is always cold in the winter. Before we had the boiler, when she'd complain about being cold, I would go down into the basement and throw a couple logs in the furnace. If she didn't get any warmer, she'd say "Wha'd you throw in there, a couple of TOOTHPICKS?" So toothpicks are the fuel of choice in our house.

 

[webie]

Sorry but I need good WOOD as hot as what the girl friend gets sometimes .

 

[MarkJ]

Sorry but I need good WOOD as hot as what the girl friend gets sometimes .

As Jim Morrison once said "baby let me light your fire" ;-)

 

[JayDogg]

Im in the process of installing 500 gallons of pressurized storage now. The past week we let the fire go out in the tarm because with a well insulated house and temps reaching 70's during the day and 40's at night, the house never gets below 70 with the heat turned off. The only source calling for any BTU's is the DHW and I cant stand the sound of the oil boiler firing every so often to keep it up to temp.
Now for a few questions for you pressurized storage guys: I want to put a hx coil into the top of the 500 gallon propane tank for my well line to run through before it goes into the superstor tank, have any of you dont this? and if so, do you have any pictures or a good way of explaining what you did. Also, my plumbing schematic currently has the tarm sending all the hot water through the oil boiler first before it goes out to the different zones, should this be changed over to a primary/secondary setup to be more efficient? The oil boiler is brand new Buderus, very well insulated, so I dont think there is too much heat loss from it, however, I've been told that the P/S is the way to go.
Once the storage is up and running, any ideas on how long I will be able to go between fires during dead of winter, shoulder season, and middle of summer for DHW. My house is very well insulated with sprayed cellulose, heating 3,500 sq.ft. with hydroair.

 

[Nofossil]

Im in the process of installing 500 gallons of pressurized storage now. The past week we let the fire go out in the tarm because with a well insulated house and temps reaching 70's during the day and 40's at night, the house never gets below 70 with the heat turned off. The only source calling for any BTU's is the DHW and I cant stand the sound of the oil boiler firing every so often to keep it up to temp.
Now for a few questions for you pressurized storage guys: I want to put a hx coil into the top of the 500 gallon propane tank for my well line to run through before it goes into the superstor tank, have any of you dont this? and if so, do you have any pictures or a good way of explaining what you did. Also, my plumbing schematic currently has the tarm sending all the hot water through the oil boiler first before it goes out to the different zones, should this be changed over to a primary/secondary setup to be more efficient? The oil boiler is brand new Buderus, very well insulated, so I dont think there is too much heat loss from it, however, I've been told that the P/S is the way to go.
Once the storage is up and running, any ideas on how long I will be able to go between fires during dead of winter, shoulder season, and middle of summer for DHW. My house is very well insulated with sprayed cellulose, heating 3,500 sq.ft. with hydroair.

Primary / secondary is not the only way to avoid heating the oil boiler when you're heating with wood or storage. Parallel plumbing accomplishes the same thing without requiring as many circulators. Adding a coil inside a pressurized tank is a bit of a challenge, but they make coils for that purpose. Takes some good welding. I've also contemplated an external sidearm style exchanger alongside the pressurized storage for that purpose, but I haven't run the numbers to figure out how much surface area you'd need.

A good figure of merit is around 60,000 BTU/day for a family of 4 for DHW. YMMV.