Got a little project going this week........

BoilerMan said:

Steve, are you are you using the outdoor reset for mixing or just the setpoint of the tank for boiler demand? Nice looking install, creative venting too Are there any fan-coils for quick heat or 100% radiant?

I do a lot of multiple boiler jobs, but never with anything fun like pellets. Always oil and LP.

TS

Click to expand...

We will be using the Tekmar just as a setpoint controller and of course staging and rotating the boilers.
Just purged the loops in the new part of the building yesterday afternoon and today so that 13,000 sq ft is up and running. Flipping the pumps on for those zones made the boilers stand up and take notice of what was going on. First time we have seen all 3 at 100% output.

The owner asked if there was some way we could install auxiliary heat that could be turned on and off independent of room temp when we were in the design phase of the project. He wanted something he could turn on when needed for deicing equipment when they take it inside.
We installed a pair of Modine vertical discharge units on the ceiling and set them up with 12 hour timers controlling them instead of thermostats. We've been heating the new area of the shop with them until today.

A couple things...........The reason for his request was graphically illustrated today when they drove in one of his 300+hp tractors with a 9,000 gallon manure tanker behind it.
There was probably 3 inches of solid, frozen poop and ice on the outside of the tank along with what was frozen to the interior walls. I asked the owner how much the total rig weighed and he said about 66,000#. Dry. So add another 5-6,000# for what was frozen on.
A little back of the napkin math indicated dragging that much steel, iron, rubber, plastic and poo from 0* up to 40ish would soak up around 1.8MMbtu!
In other words, the full system output for 3 hours. I had figured some capacity into my load calc for such a purpose but neglected to ask him the weight of what he wanted thawed out. I guessed it at maybe 30,000#. ZIKES!! They bring those in one at a time and give them overnight to thaw out so we should be OK.

So this brings up the other thing I wanted to mention. Radiant heat
At the time they pulled that piece of machinery into the old shop there was only one zone calling in the wash bay and the room temps were all stable at 61* T-stat setting.
Only one boiler was running and the other two were shut off on their internal aquastats. They pulled that 35 Tons of iron and steel into the shop and within 2 minutes every zone except the office was calling for heat! Air temp only dropped to 58* but that huge amount of cold mass literally sucked heat from the floor. Within 10 minutes of the machinery getting parked inside all 3 boilers had fired and were ramped up to between 60-80% output. They were chewing on that load hard. It was stunning to realize the amount of heat flux moving from the btu's stored in the 6" slab up into that cold metal. All zones except the one under the tractor satisfied within about 30 minutes but the boiler were still pounding out around 350-400,000 btu into that slab of about 4,000 sq ft. It would seem that the entire slab was pouring heat into the big iron. Normal floor supply/return temps are 110 in and about 90-95 out but we watched as the return temp dropped into the 75* range giving us a 35* T.
Wow! just WOW!!

And here's another thing. The front part of the shop was existing radiant, the new part in back has been heated with the Modines mentioned above for the last week. We could not believe the difference in the "feel" of each area even though they were both sitting at 60*. The radiant side of the building felt warm and comfortable for working. The Modine/forced air side felt a bit chilly even though the air temp was the same. I have never had a building that I was able to observe a side by side comparison of forced air VS radiant slab in such an identical situation where air temp, building construction and all other details were the same. The difference in comfort level of the radiant side was hard to believe.

Sorry to ramble .......... a lot of cool things going on with this project.

They auto fill from a 13 Ton bin JP. These will heat his place for about 1/2 the cost of LP gas and when you're talking a couple grand a month for gas that adds up.
And yes, he is smiling.

Fired up the 13,000 sq ft of slab heat in the remodeled section of his building on Thursday (8th). Previous to that the boiler(s) were stoking the existing slab which totals about 9,000, plus 2 Modine vertical discharge heaters rated at 95,000 each.
Amazing to watch that much horsepower chew on a load like that. What a ton of heat to raise that floor 30*!
The entire 22,000+ sq ft is now running 61-62* with the offices sitting at 70. The secretary strolled through the boiler room yesterday and commented that this is the first time she hasn't had to run the electric heater in her office since the place was built 8 years ago............makes me grin when I hear things like that.. Outdoor temps were single digits to below 0 all day yesterday and Thursday when we pulled the trigger so we are pretty much at design/worst case conditions. Wind was running between 10-20mph along with it. Even the local snowy owls were holed up somewhere out of the wind.

Total pellet use since fire up on December 31 stands at 2.33 Tons as of a couple hours ago when I checked to see how everything was stabilizing. (all boilers were asleep) The system ate nearly 1,200 # on the day we fired up the 13,000 sq ft section but I was expecting something like that really. The floor was in the low 30* range and it took it up to about 64* in less than 24 hours. The next day the entire building used only 210# of pellets.
Water temp going to all zones is currently set at 110* and returns vary from 70* to about 90* depending on the zone.
We are going to track daily use and outdoor avg temp for the next month to try and get a handle on what annual pellet use might be.

velvetfoot said:

Do you get this info from the control panel?

Click to expand...

Pellet use ( in 1/100 of a ton) is one of the line items on the control. Same operating system as your BioWin.
I simply made up a chart showing the date, amount used on each boiler and the OD temp and we or someone there write the info down.

Well we found out what kind of power those babies have yesterday.
AND we found out the amount of fuel it takes to generate that power.

Yesterday of all days, the crew showed up to seal coat the 13,000 sq ft of new concrete in the building. Temperature at 8AM when they started was 62* inside and -23* outside at the site.
The coating material is a very high VOC liquid that will give you a buzz you will never forget if applied without ventilation. So............ The 20' wide overhead doors on the north and south ends of the building were raised about 2 feet to allow fresh air into the space.

At -23*

All 3 boilers sat at 100% output for nearly 7 hours straight sucking fuel like it was going out of style. The high outdoor temp for the entire day barely made it above 0* and the doors were raised from 8AM to about 3:30PM when they finished up.

The building temp never dropped below 50* as indicated on the thermostats. But the pellet use! Oooo la laaaa Between the 3 of them they gulped or maybe inhaled is a better word, .41 Tons or a tad over 800# of pellets in the 24 hour period from about 5PM Monday to 5PM Tuesday.
At temperatures ranging from -20's to about 0. With the doors cracked open.
I don't think that the pellet use is out of line given those conditions and quite frankly am amazed the system was able to keep the building in the 50* range.
Those big babies were hogging all day long.

sloeffle said:

Great thread. I wish more of the farmers in my area would not be in love with their OWB's as much as they are. Probably a different topic for another day.

Back on topic. Based on the number above and some number crunching. I came up with the efficiency of the OWB at around 29% in this case. Does that seem in the ballpark ?

Click to expand...

I would err on the charitable side and call it 35-40%.

Yes it's piped right to the pit. He raises a couple hundred dairy cattle to sell to other local dairy farms but has no milking operation himself. The waste output from them and the wash water is far below what would be needed to provide usable gas output for any kind of viable energy generation.

I know that some of the big dairies around here with 2000+ head actually milking have looked into digesters and all say there is no actual payback. Especially when they calculate what is lost in soil nutrients because they are not recycling it back on their fields.
2000 head producing milk means there are actually close to 3000 head on the farm from calves to heifers just coming fresh for the first time. That is a lot of poop.

99% complete. A couple stove pipe hangers to install and some additional tweaking on the Tekmar but the system is basically done.

We've been tracking pellet use since start up 12/31 and yesterday the total was 4.86 tons. So a fuzzy bit over 400 pounds per day average.
Call it 8,250btu per pound and you're at 3,340,000btu's/day or 140,000 per hour. Pretty amazing for the size of the building and what they are heating.
Call me a believer in pole barn type construction done well and stuffed with blown cellulose in the walls. Attic has 14" of blown in and those huge overhead doors ar 2" foam filled. Insulation doesn't cost, it pays.

We wound up setting the Tekmar to run water temp in the buffer tank based on OD reset. Most days in the 15-25 degree range water temp target is 130 - 140*, which the Windhagers will easily tolerate.

Back to those average numbers.....You look at that and say, good grief you could heat that with a 140-160Kbtu boiler. On average, yes you could. But conditions outside are never average. We had a 3 day stretch between -25 and 0* and I watched all 3 boilers run at about 70-80% output for the 3 hours I was there. One of those days was when the guys spraying floor sealer on the cement decided to show up and the building ran all day with the North and South doors raised 2' to keep the vapors tolerable inside. They ran 100% all day that day.

velvetfoot said:

Would you be so kind as to run this by me slowly?

Click to expand...

The Tekmar can be programmed to target a fixed set point or a variable temp based on how cold it is outside.The boilers still run independently on their own internal set points but the temperature in the buffer tank determines when the Tekmar calls each one on.
Given that this system is nearly 100% low temp radiant floor, and can flow in excess of 50GPM when all zones are calling, it's not uncommon to see system temps as follow:

Boiler(s) operating near their set points of 175*
Tekmar Target temperature of around 135*
Actual buffer tank temperature at mid point of tank 90*
System supply header temperature of 115-120*
Boiler supply header temperature 160-165*
Mixed temperature going to the floor zones 100*
System return header temperature around 65-75* coming back from the floors.

Lot's of blending going on in that tank especially when everything is calling. Make sense?
.
We ran it both ways to see how the boilers and system responded and decided to let the temp float in the interest of fuel economy.

brenndatomu said:

This sounds like a MUCH bigger operation than that....

Click to expand...

The primary business is agricultural commodity handling and harvesting for other farmers. The cattle he raises are sold to other farmers as bred heifers. He's not in the dairy business in the normal sense of the word.
You really have to see the machines and his crew operate to grasp the capability of his operation.
A 100 acre field of hay is just a short day's work for about 1/4 of his crew. Cut, conditioned, chopped, hauled and piled at your place.....Thank you Sir may I have another..... BAM!
You have a 3 million gallon manure lagoon you need hauled and spread on fields 5 miles from your place? Sure, we can get that for you this Thursday and Friday. BAM!
That's his main business and he does it exceedingly well.

TCaldwell said:

beautiful job!, what capacity is the central hopper? When one gets too old to chase firewood, how about a pellet head garn?

Click to expand...

Using a figure of 42 pounds per cubic foot I spec'd the bin size to hold about 13 tons usable capacity. It's 9' tall, 9' wide and 10' long. The sides all taper in at 45* angle, starting about 4' up from the floor, to a center "trough" about 16" x 6' long where the pick up heads are bolted to the floor.

Tom I'm sure if anyone could engineer a pellet head for a Garn it would be you.

brenndatomu said:

Ahh, OK, that makes a lot more sense.
Yeah I know what you mean about having to see it to grasp it. We live in the same neighborhood as what is (or was?) the largest dairy farm in Ohio, milking ~3000 or so. Like you said earlier, milking 3000 means that they have many more head of cattle at any given time that are being raised to maturity to replace the current milking herd. The type (and size) of equipment you have pics of above rumble by here at all hours of the day at times. Having grown up on a farm I can attest to the fact first hand that it is truly amazing to see 300 acres of corn or hay harvested in hours when that size of field would have taken us days to bring in just 20- 30 years ago. Things...they are a changin...as the smaller farms sell out for the lack of being able to compete with these giants they are bought up by said giants and custom farming operations such as the one you guys did the install for are starting to pop up all over. One custom farming operation here locally works all over the state and even neighboring states.

You're install there reeks of some mighty fine workmanship BTW!

Click to expand...

Thank you kindly.

I too remember working on the farms of my uncles when I was a teenager, standing on a hay wagon stacking bales behind his old Oliver 770, then driving them back to the barn, unloading and stacking again in the hay mow. (it was always like 120* up there)
A 40 of hay took 2-3 days...... A 40 takes these guys about an hour to chop, condition and merge in the morning, then if it's dry in the afternoon a pair of their 800HP Klaas choppers and about 10 trucks descend on the field and the whole thing is bare in maybe 30 minutes. Amazing