Wood Gun E500 Gets a Belly ... and more

[jebatty]

Deep Portage, a 56,000 square feet educational institution located in north central MN, is in the midst of some big energy improvements, including this 4000 gallon storage tank to serve its Wood Gun E500 boiler. The tank will be plumbed to operate as a hydraulic separator and should be in operation by mid-September. Included will be digital panel meters and DS18b20 sensors for data logging at numerous locations. We also will be able to make an accurate determination of gpm flow using a differential pressure gauge, resulting in the opportunity to present even more accurate performance analysis this winter, along with improved performance analysis of the Garn WHS3200 fraternal twin also in operation.

Other energy improvements at Deep Portage include a Froling L50 with 1600 gallons storage to serve a separate structure, a solar voltaic array and solar hot air units (all to be on line in September); and an evacuated tube DHW solar heating array and wind turbine, both now in operation.

 

[goosegunner]

That is a nice looking tank. What brand is it?

Do they make smaller tanks for residential?

gg

 

[jebatty]

The tank mfr is Midwest Tank Company, Big Lake, MN. The 4000 gallon tank was made from stock material. We had looked at some other sizes and configurations, but those would have been custom, so we went with the standard tank. Midwest Tank Company

 

[PJF1313]

J.A. -


Do I see "ANOTHER 48 hours" in your future this winter !?

I'm mostly in the stick burning area, but I did follow your last tour there last winter. VERY detailed and explanatory, even for a newb/"curious interest" like me!
Are you planning on doing your "survey" again this year with their additional storage? Hopefully you can get a week of good temps for your comparison.

 

[jebatty]

PJ - total recall, Dude! And the answer is "yes" -- another date night or two with the Wood Gun and Garn. For those who might not know what this is all about, see Night Out.

Within the next week or so I hope to be able to install the differential pressure gauge on the Garn circulators, both sides of the HX, to get an accurate gpm flow determination vs the calculated flow used in last winter's "night out with the Garn" data analysis. As appropriate, I then will recalculate the Garn performance based on the revised gpm flow. I won't be able to do the same with the WG because of the re-plumbing involved with the new tank, but I will get a gpm flow determination with the new setup, and I then can use that this winter for another night out.

I expect that the 4000 gal tank combined with other replumbing affecting the WG will result in enhanced performance from the WG. A night out this winter will produce the data to make this determination.

In addition to the "more" mentioned above, this summer Deep Portage also installed new windows in a large portion of its structure, new doors, and added other energy conservation enhancements. My expectation is that these will have reduced the heat load for the structure, and therefore I expect that both the Garn and the Wood Gun will be able to meet demand to even lower outside temperatures that last winter.

 

[jebatty]

Early heating season experience with the new 4000 gallon storage tank evidences near nirvanna of effectiveness and simplicity in operating DP's Wood Gun E500 and Garn WHS 3200. With outside temperatures in the mid-20'sF to low 40'sF, the extra storage is effectively allowing full load burns for both boilers and btu storage that is carrying DP through the night without refueling either boiler. System/storage temperature entering the no burn period (after 7-9:00 pm) is about 155F (both the Tank and Garn), and by 6:00 am system temperature is about 129F. Total Tank + Garn storage is 60,000 btu/degree, or about 1.56 million btu's over this temperature range. As the weather cools, system/storage temperature may be brought up to 180-185F, which should allow about 6 hours of heat from storage (180F to 130F) at an assumed draw of 500,000 btuh. This should be pretty close to actual for temperatures ranging down to about -10F.

As to simplicity during this early heating season, both boilers are initially fired, about 1 million btuh total output, and the system needs are met quickly plus storage is charged. Then the Garn is normally allowed to burn out after a couple of hours and only the WG is used to meet system needs during the day and raise storage to the current 155F target. Storage includes the 4000 gallon tank and Garn's 3200 gallons, and the WG will bring both up to 155F. With this much storage, any wood loading for either boiler can be a full load (100 lbs+) with no concern about either idling the WG or producing more btu's than are really needed.

Before the Tank, WG idling was an issue, which is not harmful to the WG according to the mfr, but this big WG awakes from idling with a "puff" aka a small explosion which is disconcerting to frightening. No more idling for the WG. Also, some may recall the issue DP had with the motorized boiler water protection mixing valve for the WG. This was plumbed and controlled incorrectly by the installer. The plumbing was corrected when the Tank was installed, and a week ago I solved the control issue. Finally the mixing valve is operating and controlled correctly. This also has resulted in greatly reducing the likelihood of WG idling as well as improving the efficiency of the WG operation.

The real benefits of the added storage and its effectiveness will come this winter as temps plunge to -35F and lower, the winter winds howl, and the snow blows and swirls around a warm and comfortable facility.

 

[muncybob]

Impressive indeed! The "puff" that the WG would give from idle...were the stack temps still above 200? If mine awakes from idle and the tack temps are over 200 to 250 I will get the same reaction.

 

[jebatty]

I don't know what the stack temp was when it came out of idle. There was no thermometer on the stack at the time. Since then I have added to the monitor panel a K-type digital panel meter to provide continuous stack temp readout. The immediate benefit of the meter is that at a glance you can tell whether the WG needs refueling without opening the firebox door.

 

[Gasifier]

Wow. Cool. Jim, I can't remember if you have mentioned this before or not. How much wood does DP go through in a full season?

 

[jebatty]

Past experience is 85-90 cords of mixed oak (large component), birch, maple, ash and a limited amount of aspen and pine. This coming season will be of interest due to substantial energy saving improvements in the 56,000 sq ft structure plus solar supplement to DHW and plus a small amount of solar hot air space heating, and then also adding a Froling to serve an additional 6000 sq ft structure. The heating season is starting out warmer and later than last year, but wait and see.

 

[Gasifier]

Past experience is 85-90 cords of mixed oak (large component), birch, maple, ash and a limited amount of aspen and pine. This coming season will be of interest due to substantial energy saving improvements in the 56,000 sq ft structure plus solar supplement to DHW and plus a small amount of solar hot air space heating, and then also adding a Froling to serve an additional 6000 sq ft structure. The heating season is starting out warmer and later than last year, but wait and see.

:bug: And those aren't northern New York face cord. Are they? ;-) Wow. Oh my god. That is a lot of wood. How many volunteers does that place have?

 

[jebatty]

Your right, these are full 4 x 4 x 8 cords. All the wood is purchased from local stove wood suppliers who cut, stack and dry one summer on their own property, and then deliver and stack in DP's wood sheds for a second summer of drying. One to three part-time persons are hired to move wood to the boiler building and fuel the boilers on a regular basis, and then normal staff also fuels the boilers during the daytime and evening. With the wood at the boiler buildings, it may take about 5-15 minutes of time for a staff person to load a cart and toss a 100 lb load of wood in a boiler, which would be a typical fueling. The number of fuelings each day, and whether one or both boilers, depends on weather conditions. Of course, as mentioned, storage this year will play a big role in reducing the night fuelings, especially.

 

[Fred61]

I got my "explosions" in my Wood Gun when it short-cycled. If it had not been in idle mode long enough to deplete the gasses in the chamber. I guess the time in idle could vary before the gasses depleted depending upon the load of wood, how much, whether it went to idle during peak burn or perhaps even chimney draft at the time of idle, although that is less likely due to the positive combustion air shut-off.