afblue said:
I have been doing some internet pricing on Gasification boilers, and I have come across boilers such as Attack, and Atmos that seem to be priced rather attractively. I have read a few threads about these boilers, and the construction seems to be on par with other gasification boilers. Who out there has or had experience with these 50Hz systems, what needs to be done to convert them to run on 60Hz, and is it worth the hassle. I am seeing prices for 32-35KW boilers between $3700-$4200, thats saving $1200-1900 compared to the next priced level gasification systems like 40KW EKO or Biomass which are over sized for my application anyways.
Am I missing something here or is there a good amount of savings if I am willing to do a little more leg work?
WRT Attack, I've been running a DP 45 since the last week of December, so not a lot of experience, but here's some observations.
First things first:
Do you need UL listing?
The one I got from Smokeless was equipped with a 60 Hz Dayton motor [see photo]. Seems to be more motor/fan than is needed, even on slowest speed the air inlet needs to be restricted substantially to prevent too high a firing rate, IMHO.
Like the Atmos, there are no fire-tubes, so the exhaust is free flowing enough that it can be run with the induction fan turned off if you've to enough flue draft. I've only got 10 ft of flue, so although I've got enough draft to evacuate the flue at all times, I still need the fan unless it's a cold windy day.
When I charged my tanks the first time my 16'x32' boiler room was up over 90 degF. The room is well insulated but not all that tight just yet, so that seemed awfully hot to me. I investigated and took the skins off the boiler and found about an inch of wispy fiberglass pressed into a 1/2 in gap on the top and sides, and the bottom had no insulation at all. I discarded the top panel, and for the side panels I was able to bend the ears that support the panels out away from the boiler to about an inch and a quarter of clearance. Then I wrapped the boiler with three loops of 1.25"x4" light aluminum channel stuffed with rock wool, and then placed panels of rock wool between the channel loops [see photo]. This brought my boiler room temperature down below 50 degF.
And the RK2001U controllers appear to be junk. Mine got to the point where pressing any programming button would cause the fan to stop briefly, and then sometimes you'd have to tap it as vigorously as you dared to get the fan to run at all. Another hearth member was having trouble getting stable temperature readings. Two failures in a sample even as large as hearth readership is not acceptable by normal industrial control reliability standards. In my case the fan speed function is now being performed by an inexpensive solid state PSC/shaded pole fan speed control and the over-temp fan shutdown function is being performed by a salvaged Honeywell mechanical aquastat that I can trust to shut the damn thing off it gets too hot, unlike the RK2001U.
And the thing holds 30 gallons of water, which takes however much time and btus to heat up. And then when the burn is complete you've got a hot boiler full of hot water and there it sits. I ended up wiring in after-burn purge logic such that when the fire is out and the top of the boiler is hotter than the water returning to storage, then the return water injection pump runs whenever the transfer-from-storage-to-the-house-pump is running.
But other than the disappointing insulation and the worthless controller [which are likely faults with many other boilers], the boiler itself appears to be stout and well conceived, gasifies well, starts well, runs clean, and doesn't waste fuel. The doors work right and seal tight, and the bypass damper works great for avoiding smoke in the mechanical room.
I've throttled the gasification nozzle to about 1/2 to 2/3 of the stock opening to let it run effectively at a lower burn rate and get better heat extraction. This seems to work quite well, it burns clean and turbulently at an average net output of about 60,000 btu / hour. I'm using 16"-18" fuel centered over the nozzle in a 30" fire box.
But today I'd be looking real hard at a Varmbaronen 25kW or 30kW, just by the looks of them, and also due to the fact that I'm finding out that a smaller boiler would be preferable.
[Edit 2011-10-31: Varmbaronen are no longer the super bargain they were when I wrote this, but I still like the low-mass lean mean engineering even at the higher pricing. However note that they have a max 1.5 bar operating pressure as opposed to the more normal 2.0 bar (30 psig).
The Attack has been running great all of last year and as required for DHW and hot tub throughout the off-season.]
Cheers --ewd
