Converting to wood heat....getting cold feet..

[rswyan]

SPIKER,

</font><font color="blue" class="small">( anyhwo it was smaller than the standard outdoor wood stove as it was lined with fire brick on the bottom... not sure how the water is heatd that way if much of the heat is absorbed by the fire brick!?!? )</font>
The unit is insulated and there's a waterjacket around the heat exchanger which is in back on the firebox (The firebox itself may not even be waterjacketed - it seems like it wasn't, but I can't say for sure right offhand. Not jacketing it would keep the combustion chamber much hotter - no water cooled walls) The exhaust gases run through the heat exchanger on the way out through the flue.

</font><font color="blue" class="small">( not sure how they get the much hotter temps, unless they are making it a STEAM BOILER. the brochure didn't have much info at all. like the web site not much there. )</font>
It's not a steam boiler, just hot water. Actualy there is quite a bit of info on the website but requires a little digging around to find it. From their website:

"The wood gasification combustion process in the Solo Plus boiler begins when the small, quiet draft fan turns on in response to the boiler’s heat controls. The draft fan blows fresh air into the top of the firebox and down through the wood and live charcoal bed. This hot air and smoke mixture is forced through a slot in the top of the ceramic combustion chamber. Super-heated secondary air is then injected into these gases. The combination of the wood gas and smoke with the high temperature oxygen results in a super-hot 1800° flame in the ceramic combustion tunnel. This is the “Wow, that’s unbelievable” process we call wood gasification. The gases stay in this hot, turbulent environment long enough to achieve extremely high combustion efficiency. The resultant heat passes into the vertical heat exchange tubes giving off heat to the boiler water for house heating and domestic hot water demands. The combination of optimum combustion and maximum heat exchange efficiency is what yields the unusually high overall boiler heating efficiencies of 80-85%"

Also:

"Most wood boilers can burn with either good combustion efficiency or good heat transfer efficiency, but not both. To achieve good combustion efficiency, the boiler is burned fast and hot with little smoke (unburned fuel). However, with this hot burn, the stack temperature is high with low heat transfer efficiency and substantial heat lost up the chimney. On the other hand, good heat transfer efficiency with low stack temperatures is achieved with a slow burning fire. However, with this slow burning fire, lots of smoke and creosote are produced which is unburned fuel being lost up the chimney resulting in low combustion efficiency."

"The HS-Tram Solo Plus and Excel boilers utilize the process of wood gasification to maximize combustion efficiency. The controls of these boilers do not allow for a low smoldering fire. They burn hot or not at all; always producing high combustion. "

"Because the combustion efficiency of the Solo Plus and Excel boilers is so high, the heat exchange tubes can be designed for maximum heat transfer efficiency without having to be concerned with the formation of creosote in the smoke pipe or chimney. The available fuel has already been consumed and there is nothing left to waste or pass unburned up the chimney."

As well as:

"WOOD CONSISTS OF TWO DISTINCT FUELS:"

"The combustible gases: These are given off mostly in the beginning stages of a fire after the new fuel is heated. These gases are visible as smoke and flame."

"The fixed charcoal: These are the glowing coal-like red embers remaining after the gases have been driven from the wood.."

"Scientists have found that over 50% of the heat value in wood is in the form of these combustible gases. The complete burning of these gases has long been the main concern of engineers and designers seeking clean wood-burning devices."

"In designing the Excel and Solo Plus Series, HS-TARM engineers decided that the best way to burn these gases was to use a firebox with two distinct chambers. In the primary chamber (firebox) the wood charge is ignited. The burning occurs at the bottom of the firebox and the heat from the fire bakes the wood above releasing the wood gas from the fuel. The combustion draft fan then blows these gases through the live coals and into the superheated ceramic tunnel where secondary air is injected to complete the burning process."

"These boilers burn so clean and hot that virtually no visible smoke comes out of the chimney. The picture shown here is a close-up of the 2000 degree flame that occurs in the ceramic tunnel. How clean is clean? Tests have shown that the HS-TARM boilers can burn wood with a smoke output of less than 1 gram per hour. This is equivalent to the smoke released from one cigarette. an HS-Tarm boiler burns up to 100 times cleaner than an older woodstove. With millions of folks now burning wood it is very important that we burn it wisely."

 

[rswyan]

Dan,

I checked late last year and got the same pricing you quoted, although with the steel situation it could have very well gone up by now. I was looking a Solo Unit since we already have a natural gas forced-air furnance.

Since our basement is 85% finished (drywalled ceilings), installing radiant floor heat was not an option and I would have gone (or will go) with their heat exhanger that will mount in the bonnet of our forced-air furnace.

I have the room for water storage, but getting it from them is pretty pricey (seems like it almost doubled the cost.) I might try and roll my own.

 

[_RaT_]

Thanks Randall. /forums/images/graemlins/wink.gif

 

[Gomez]

I know the Travis Industries (Avalon, Lopi, Fireplace Xtrodinair) units do not have a CAT. Actually, that's one of the reasons I bought a Lopi insert. They use an air injection system that helps ensure complete combustion and minimize emissions. Actually, it's pretty cool to watch in action.

 

[_RaT_]

We installed a Regency at our cabin in Tahoe and did not want the education curve involved with a catalytic convertor especially with so many different folks using it. The air injection works superb and there is no element to replace. The fireplace made all the difference in the world. Prior to the Regency, we made folks bring up their precious firewood. Now, we not only supply the oak firewood, we encourage them to use it instead of the natural gas furnace.

 

[adlertom]

</font><font color="blue" class="small">(
Many that burn wood in outside units burn wood that is not dry (dry to me is cut to 18" length, split to less than 8" thick, and kept dry under waterproof cover for at least 3 years!). But, many around here just cut in the summer and burn that winter, meaning most of the wood energy goes to boiling out the moisture, and makes for a lot of steam, creosote, and smoke.

)</font>

I burn whole, unsplit logs in my outdoor wood furnace. I don't split them because that would be extra work. Unsplit logs do take longer to dry however. Two years is ideal. Larger diameter logs take longer to dry than smaller diameter ones.

One mistake I made in my first year of operation was not cutting enough smaller logs. You need the smaller logs to build a nice "base" for your fire that will get the larger logs heated up and burning. It's very hard to get a fire going using only large logs. Best to start with kindling/twigs at the bottom, with smaller logs stacked on top of those, followed by the larger logs.

 

[ejb]

>>So what is the big deal about seperate flues if the system works fine?

Anyone know what the answer to this is? Its against code here in mass, but I don't understand what in theory they are protecting us from...

BTW: I got a package from TARM today that I ordered over the internet...real nice looking setup but $$$$$. Getting real close to $10K with the options you need to install...ouch.

Yet, with almost $3k per year in oil costs, I haven't ruled out the TARM.

 

[beenthere]

Potential for back draft back down a connected flue into one of the connected 'heaters', I believe, is the reason. But a lot of code is just 'because' a desk clerk thinks it is a good idea, IMO. Trying to be the big 'brother' and thinking no one can really do this thinking for themselves.
Probably are some instances where a fire in one unit doesn't draw right and wafts back into another when something plugs the single chimney, or a downdraft happens. This would theoretically cause fumes to come out of the other unit connected. A better draft will likely be the result of only one unit attached to each flue or chimney, and sized for that unit, rather than shared with another. If there is a fan-induced draft, then more of a problem might be encountered with two into one.
On start-up, sometimes getting the entire chimney warm enough to get a good draft is a problem, and having a second stack plugged in wouldn't help any.
Probably most times two into one would work fine. It's the rare times that it doesn't that we are being protected from, by the 'big' govt. We voted them in, so maybe we should vote them out. /forums/images/graemlins/wink.gif

 

[EdK]

I've spent a considerable amount of time and energy in the process of "rolling my own" thermal storage system. After considering EDPM lined vessels, epoxy coatings, polyethelene tanks and so on, stainless steel remained the most attractive option for obvious reasons. However after checking prices from the various manufacturers serving the solar water heating market my socks were blown clean off! I poked around at some used stuff and then the light bulb upstairs lighted: eBay

I have purchased two used food-grade industrial stainless tanks (1000+500gal) which I plan to isolate with ball valves to allow for 500/1000/1500 gal storage capacities based upon time of year demand ranging from domestic hot water only in the summer through to the depths of winter. I also purchased the heat exchanger through eBay - a new surplus copper/nickle marine unit at only 15% of original list price.

This is a project to be sure - a lot of time. To be fair it is also somewhat a labor of love in that I look forward to being totally self-sufficient one day and feeling good about it.

 

[bebster]

The code people are worried about the gases of one appliance on the flue being back-drafted to the other appliance and out into the house. Imagine if you ran your car in the garage and hooked the exhaust to the flue -- you might have a way of getting carbon monoxide back into the house.

If the unit costs you $10K and you can save 1/2 of the $3K you spend on oil, that's a 6 year payback. That's pretty good investment by any measure. Plus you can have the pleasure of knowing that you are living off your land and not supporting some oil cartel somewhere. I'd go for it if I were you, assuming you want to deal with the wood harvesting and loading. This thread is making me seriously consider these alternatives for economic and even patriotic reasons. Wood heat plus a wind generator for electricity and I figure I'll have done my share of reducing our dependency on foreign energy sources.