Tarm vs Greenwood

Weezbo

and under Aqua Therm...Omega wood boilers..

if i had a spare dollar these things Look like they do what they do :)

Glen

A client and I are -

involved in a friendly discussion; Tarm vs Greenwood. I'm supporting the Greenwood boiler while Tarm is being argued by the HO. I see clear advantages of using the Greenwood - especially as this home will be off grid, with PV and diesel genset backup. Most importantly though is the storage tank; required by Tarm not by GW. As well as the large firebox and door, rounds vs split etc. System will be 4000 sf radiant (Roth panels upstairs, in slab in basement), with a small LPG boiler as freeze protection or while HO is away, although this is unlikely during winter. Your opinions? Or are there other gasification boiler that should be considered?

kevin coppinger_4

tarm is very good...

although very $$$...the storage tank I feel is very important. I would not do a gasification set up w/o one. It lets you burn hot for as long as you can and store all the energy...if you slowdown the burn you get less enegy and more creosote issue. kpc

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hot_rod

A couple others

http://www.alternativefuelboilers.com/

www.newhorizoncorp.com

hot rod

Leo G_101

Kevin

Greenwood's way around this "hot" burning issue, is that they treat their boilers like a gas boiler. They control the combustion air. SO like a gas boiler, when the call for heat is satisfied, the combustion air is closed and the burn stops. Because of their huge ceramic refactory, when a new call happens, the heat within the ceramic is enough to re-ignite the waiting fuel source as the comb. air louvre is opened. So you keep the energy in the solid form for when it is needed. In theory, this should make the Greenwood more effecient then the Tarm over time.

I like the concept, and almost became a dealer for them, here in Vancouver, but could not make the numbers work on my end. Though if I ever move to my property up country, I will probably give them a holler again and see whats what!

Glen

I too -

like their proximity to BC - (I'm in the East Kootenays) - and the fact the factory is just across the 49th. I have been well intentioned to visit the factory -
But we will look at HR's/Weezbo suggestions too -
So I gather the storage tank is a solid recommendation - regardless of boiler used? So then do we consider a Viessmann bivalent (450 L); bottom coil for the DHW and top for radiant out? Or is a very large amount of storage recommended? I can see these project costs climb incrementally - the notion though is long term, medium to low cost heating/dhw production.

hot_rod

Controlling to combustion air

is a big step, but I feel it is the gasification, re-burning the exhust gases that makes the efficiency numbers go up.

I have installed a few different brands of gasification. Tarm, Atmos EKO, and Dakon.

The EKO Vimar I have actually has a variable speed combustion fan, and outdoor reset build into the control. I'm told EKO builds the wood burner boilers for Viessmann.

I see the Econo Burn also has a variable speed fan. This helps the overshoot quite a bit, but some storage is a big help for low load conditions. Just like a gas fired boiler you hate to have it short cycling all day in mild weather or under low loads.

On New Horizons website I see Zenon is trying to add a buffer tank under the boiler. That is a 500 gallon tank he had built in Poland to buffer with, and also trying to build an outdoor model.

As I shop around it looks like New Horizion has the best deals. Econo Burn is close with their 100K unit. Built in Dunkirk, NY.

hot rod

Steve Ebels_3

For a bit of a curveball

Look at a Garn. Drawbacks are that they are huge due to the storage being integral in the unit, the smallest of which holds 1,500 gallons, and the fact that the insulating "cabinet" has to be field fabricated.

Of all the many brands of wood burners I have installed and/or serviced, the Garn is the only one I've ever seen running a flue temp less than 350* and doing it cleanly. Efficiency is lab tested at over 75% and they exceed the new ASTM emission standards by a wide margin. (Warnock Hersey spring of 2006)

They are also the only unit I'm aware of the has a proven 30 year track record of excellent efficiency and reliability. If you're serious about burning wood, it might pay you to look at one of them.

Leo G_101

Glen

their concept is to move the heat energy storage from a water heat sink to their huge ceramic fire chamber. They are using the ceramic chamber to hold the excess energy. Again for two reasons, one for the heat sink, the other for re-ignition. Their claim is about 85% overall efficiency, one of their reasons for deleting the water storage.

In my way of looking at this boiler, I was going to run at least one Allied 120 gallon dual coil hot water tank in line for the home heating. Their technical guy assured me that this plan was not needed. So then I figured that I could always cut something in at a later date if needed. Teamed up with a tekmar control, I really believe this wood boiler could be a very good choice. Would like to wait a couple of years more though, just to see how they actually work in "real" conditions.

As always, google the name and see what you come up with.

Leo G

hot_rod

Not to bad for combustion efficiency, Steve

my question has been keeping 1500 gallons of 180F water insulated against sub freezing temperatures outdoors?

hot rod

Steve Ebels_3

Valid concern

I have yet to install one directly outside but I think it could be done. So far they've all been in buildings like pole barns, and others of that type. Unlike a lot of wood boilers, the Garn's are UL rated for indoor installation. We just frame up a stud wall on all four sides and top with 2" of high density foam underneath. The unit sits right on the foam. The front gets steel studs just in case but there is minimal fire danger due to the design of the door and also the negative draft present at the opening. We build the enclosure to allow for a minimum 12" of space and fill it with lose fill fiberglass. It does make for a big enclosure which as I said before, is a negative in some instances. They'll hold heat for a long time done that way. Days. Of course even a 10* drop when dealing with 1,500 gallons of water is a sizable amount of heat loss.

I have yet to find a perfect wood burning boiler but it would just about have to be something that allowed for modulation and clean shutdown of the fire. Automatic re-light would be mandatory also. Something along those design criteria would just about demand a pelletized fuel like a lot of the high efficiency wood burners are set up for in Europe. I'm sure you saw some at ISH.

Leo G_101

an aside

here on the North Vancouver waterfront, we have one of the worlds leading manufacturers of those wood pellets. Big problem when moving them from the plant to the cargo ships though. They have been fined , I think, three times in the last couple of years for too much dust in the air.

Leo G

Eric Johnson

BioMax

Zenon is now selling a couple of other boilers from Poland called the NextGen BioMax. They look very similar to the Orlan EKOs. There's a 40kw and a 60kw model. Same controller, I believe. He's also putting one of those in a little tin shed with hw storage for outdoor installation.

I've got the EKO 60, (which I am looking forward to firing up fir the first time) with 1,000 gallons of hw storage.

I think gasification is the coming thing, but you need dry wood and some kind of storage. Garn, Tarm, Greenwood, Black Bear, Adobe, Orlan, etc. all address the storage issue in different ways.

Glen

thanks to all

as I now have quite a bit of literature coming this way. And it seems that some sort of storage to improve the legs of the boiler is beneficial. Again - thanks