Heating Large Shop in Alaska W/ Sequoyah Outdoor Boiler

lsayre · Post by **lsayre** » Sun. Oct. 09, 2016 8:23 am

Why is there any need to run an open loop for wood boilers? Is it due to wild temperature/pressure swings? Or alternately, are they not pressure vessels?

McGiever · Post by **McGiever** » Sun. Oct. 09, 2016 8:25 am

lsayre wrote:Why is there any need to run an open loop for wood boilers? Is it due to wild temperature/pressure swings? Are they not pressure vessels?

They are tanks, not pressure vessels.

The difference is $$$

lsayre · Post by **lsayre** » Sun. Oct. 09, 2016 8:26 am

McGiever wrote:They are tanks, not pressure vessels.

Bummer! My boiler is an ASME certified pressure vessel.

Well, at least beyond the heat exchanger the system will (presumably) be pressurized. The actual heating loops (secondary loops) will therefore only have friction head, right? And only the primary loop will be open?

Height head is straight forward, and is far easier to calculate than friction head. It merely is what it is.

Best in that case to put the heat exchanger in close proximity to the boiler. That would certainly minimize (to perhaps even negate) the issue.

lzaharis · Post by **lzaharis** » Sun. Oct. 09, 2016 10:06 am

AlaskaCoal1 wrote:Thanks again to all the help... I have racked my brain on a way to do this as an open loop system from lowering the heaters etc..... it can be done but not really sure how to calculate the additional head since it will have to lift the water and that might just add very expensive interior alaska electricity negating the initial cost savings.

SO...I think I have decided that the best way to do this is to pipe the boiler which is an open loop not pressurized to a heat exchanger. Then from there go with a closed loop system. I have most of the parts manifolds zone valves etc from another property I own that is not using hydronics anymore.

How do you figure the head loss of the heat exchangers .... some of the ones I have found have the specs some do not and google does not always render the results. I see there is quite a range on the head loss. This will affect both the open loop side as well as the closed loop side.

Also since I figure the boiler is a 300K I figure 50% efficiency just to be safe. if it is more then so be it. So like suggested I am only planning on 150K. The previous owner said he ran 170 degree water due to the fact that the coal would continue to heat and running up to 180 or 190 would result in boil overs at the boiler.

I would like to transfer as much of the heat to the inside as possible so I have it available if needed. According to the TACO worksheet the 1 1/4 pipe can transfer 150K but at delta T =20 would take 15 GPM that exceeds 1/1/4 but at delta T =30 it can be done at 10GPM which can be done according to the calculation. (F= Q/(500*delta T))

I was wrong about the heaters they are more like 40K units and with water temp factors they will be like 35K units at 4 GPM each. Also my base board heaters will produce another 35K at the 1-4 GPM rate. so with the heaters I have they will not match the coldest day heat load but as has been stated that is not every day and I do have a hand fired coal stove in the shop to help out... this should at least keep it above freezing and close... -30 outside and even 40 to 50ish in not bad... I have a LOCKE 500 I am trying to get up and running or will put my TLC2000 in there for those really bad days... not where I live so it does not have to be like my house at 70 24/7. Also thinking of just letting the baseboard heaters run all of the time since they are low flow and should not require a large circulator... In alaska there are very few winter days that some heat is not needed anyways and they would most likely run anyways... then zone the hanging heaters since they pull more electricity.... ELECTRICITY here is out of site.

Here are the questions--- sorry for the long post.

---Since the close loop and open loop are separated the flows can be different correct???? I understand that If I exceed drastically then the temps will suffer but at least the circulators will not cavitate.

Hence 10 GPM to Xchanger and three 4 gpm hanging heaters and a small loop of baseboard heaters at 1-4 GPM.

If all of this is correct then the HEAD LOSS is the only thing I am having trouble with to ensure I have the right pumps to accommodate. I can figure the rest of the head loss but not all xchangers give you the loss or the psi operating .... any rules of thumb or ways to calculate.

Also other specs -- the boiler has a Star 21F three speed and I have another Grundfos UP 26-64F single speed if needed. Hoping that the head on the closed loop side would allow for a variable speed circulator like the bumble bee. low cost to operate.

This head loss crap is the real design hang up I have. I also have a plumber that I work with that works all day with large commercial steam system and he is coming by so I will keep you posted on what he says.

Finally... I have not looked into steam... seems way above my ability.... second the radiators .... where do you find them... have seen NONE here in alaska ... used or otherwise. --- third I have not read the books yet only califfee idronics.... working, keeping up with daily chores and this LARGE project consumes me... be glad when I can sit back drink a beer and enjoy.... there comes a point when a project loses it glimmer and this one is getting real close to that... with final insulation to be complete... hydronics and electricity to hang before I can start to organize the man cave and enjoy.

really want to get this up and running as it is getting cold here.

Thanks for all the help.... I hope that I can one day be as helpful

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There are lots of homeowners with steam heat so no worries there. Plumbing it right and treating the boiler water for the steam heat system to allow the proper amount of expansion is a necessity to distribute the steam heat and keep corrosion to a minimum.

Steam heating is easy sweating good copper pipe in new construction or if you have good threaded steel pipe.

Just so you have some perspective the Empire State Building uses less than 2 pounds of steam pressure to heat the entire building, sub basement and basement in the bedrock.

Short of adding water tanks for storage for your workshop I see no other option unless you invest in a P+M stoker or an EFM coal stoker both of which can handle the Usibeli coal

The more water you heat the more thermal mass you have as I mentioned and filling the OWB with firebrick as I mentioned will only help you as I described in detail with how I filled my boiler and how well it worked.

Post by **Rob R.** » Sun. Oct. 09, 2016 10:08 am

Steam is not an option with an outdoor wood boiler.

lzaharis · Post by **lzaharis** » Sun. Oct. 09, 2016 10:50 am

Hello Rob,

I mentioned using steam as an example/option only in tandem with the OWB.

Wherein he could use a very very small steam coal stoker boiler with heated feed water
circulating from the hot water boiler to keep the water in the steam chest
and base/sump/mud leg hot all the time.

Don't yell, he bought the OWB already so................

With his heating load, investing in a full pallet of standard firebrick for the Sequoyah
will be less costly in the scheme of things for him. It worked for me and worked very well.

windyhill4.2 · Post by **windyhill4.2** » Sun. Oct. 09, 2016 11:26 am

In 2006 when I set up my OWB,i don't know that I ever heard the term friction head, I ran an open system,pumped the water up to my shop heater with only the initial fill giving any trouble.That design worked for 8 yrs,in 2014,i went with my EFM520 installed in a truck box which is still in use & is a closed , pressurized system.
If height rise or friction head or whatever is a problem...
Hit the easy button....
Go low...
Mount all the heaters near the floor !!!!!!
I was going to mount mine low but some "knowledgeable " person told me that I should mount them up on the ceiling ,i still wish mine were near the floor blowing that hot air across the floor instead of blowing down from up above.
Heat rises !!!
Why complicate when easy is right there in front of you ??

AlaskaCoal1 · Post by **AlaskaCoal1** » Sun. Oct. 09, 2016 12:29 pm

https://www.taco-hvac.com/uploads/FileLibrary/SelectingCirculators.pdf

This is the worksheet I am using to rough in the numbers... the relative short distance from the boiler to the shop 72 feet is really no big deal. it is the shop that with the added equivalent length of pipe added that is really adding up. Hard to figure all the fittings so I am using the length of pipe X 1.6 to get a rough idea then plugging that into the formula worksheet above.

Windyhill.... easy has been pushed... heaters will be lowered for sure. Izaharis... the firebricks have not fallen on deaf ears BUT the previous owner already accomplished most of what you did .. I will just relook and revamp if needed. He is a good friend and knows the boiler well and it worked well for him but he was just heating DHW and a short run plentum for his forced air along with some short run outbuildings... I am confident it will work ... Just really want to get the initial design in the ballpark since a good design is key to making a system work well and having the ability to tweak it.

If I had it to do over I would have bought the Harman SF360 indoor boiler that I could have bought and saved my back and the $$$ on that pipe. For the underground pipe money I could have installed another chimney for hand fired unit... bought some really good NEW heaters... etc etc.... Life lessons are sometimes not easy or CHEAP. This will work just have to adapt and overcome.

I have a 300 gal at least maybe 500 gal metal insulated tank that most likely will come into play here for thermal mass... It was here when I bought the place but with all the foam I see no inlets or outlets so it may have to be adapted .... not real sure what the owner was going to do with it I am assuming he was looking at thermal mass as well.... if it will not work I will sell it and buy one that is easy to hook up....

Post by **Rob R.** » Sun. Oct. 09, 2016 4:17 pm

windyhill4.2 wrote:In 2006 when I set up my OWB,i don't know that I ever heard the term friction head, I ran an open system,pumped the water up to my shop heater with only the initial fill giving any trouble.

Most OWB dealers don't know anything about sizing circulators correctly - they sell everyone the same 1" tubing and Taco 011 circulator. If I recall correctly you used 007 circulators, and your system contains a minimum of pex fittings (which are very restrictive), and it works good.

I would suggest doing the same thing in this case, using a 007 (or something like it) for the main boiler loop and see how it works.

windyhill4.2 · Post by **windyhill4.2** » Sun. Oct. 09, 2016 5:12 pm

Rob R. wrote:
windyhill4.2 wrote:In 2006 when I set up my OWB,i don't know that I ever heard the term friction head, I ran an open system,pumped the water up to my shop heater with only the initial fill giving any trouble.
Most OWB dealers don't know anything about sizing circulators correctly - they sell everyone the same 1" tubing and Taco 011 circulator. If I recall correctly you used 007 circulators, and your system contains a minimum of pex fittings (which are very restrictive), and it works good.

I would suggest doing the same thing in this case, using a 007 (or something like it) for the main boiler loop and see how it works.

007 is what I used then & still use exclusively & I did use as few fittings as was possible...
Not because I was smart...
Copper was $12/foot & fittings were expensive too

waldo lemieux · Post by **waldo lemieux** » Sun. Oct. 09, 2016 7:34 pm

I worry about this installation.... A forest eater is a sht pot full of work to keep fed here in the lower 48 with just an ordinary house to heat. A huge shop and a house in interior Alaska,

omg

windyhill4.2 · Post by **windyhill4.2** » Sun. Oct. 09, 2016 7:39 pm

waldo lemieux wrote:I worry about this installation.... A forest eater is a sht pot full of work to keep fed here in the lower 48 with just an ordinary house to heat. A huge shop and a house in interior Alaska, omg

I agree !!!!!

But it won't be me tending the stupid wood monster !

Scottscoaled · Post by **Scottscoaled** » Sun. Oct. 09, 2016 7:45 pm

I don't think it will be as bad as you think. He did a pretty good job of insulating the place

AlaskaCoal1 · Post by **AlaskaCoal1** » Mon. Oct. 10, 2016 2:33 am

waldo lemieux wrote:I worry about this installation.... A forest eater is a sht pot full of work to keep fed here in the lower 48 with just an ordinary house to heat. A huge shop and a house in interior Alaska, omg

Waldo... no worries here about trees... I will be using burnable dirt for my heat... easy to make that happen... when I need it I drive 35 miles they load it with a loader... I dump it in a covered storage... then I shovel it when needed... the last owner only tended his every 12 hours... he said not cause it really needed it but it was just his routine... 6 or 7 good shovel full of coal and done.
We shall see... I have wood available but hate it... if we burned only a few cords a year not to bad but 10 cords is not uncommon up here... my neighbor has a indoor wood boiler and he used 14 cords last year and that was a warm year.... granted his wife likes the house the same temp of the equator but still ... that is a ton of work. I spent a good part of my childhood gathering splitting and stacking wood... when I ask my dad why the neighbors had a log splitter and he did not... he said " I do have one" my reply was "where is it" .... "standing right in front of me"

Totally off subject but... the best lesson I ever got on procrastination was over about 3x 36 inch red oak trees we cut. My dad kept telling me that I better get out and split... I put it off for months... when I finally got around to doing it I had to drive two wedges to break it and usually had to wedge it again to quarter it before I could then work on just splitting... my dad walked out during this labor and told me he knew this was going to happen since I did not start right away... funny how he never shared that tidbit of information.

lsayre · Post by **lsayre** » Wed. Oct. 12, 2016 7:28 am

You only need to move 150,000 BTUH along your primary loop (the leg that will take the heat to your heat exchanger), and that only if the sum total of your downstream users will add up to 150,000 BTUH in demand. If your users will all total to only 135,000 BTUH, then that is all you will need to move along the primary loop.

From there (post the heat exchanger), your individual closed loop "zones" will each only need to move as much heat as its user(s) require (currently I'm seeing this as 40K BTUH per your corrected assessment of your Modine type heaters). Each of these zones will be required to have its own circulator.

I'm concerned (based upon your struggle with the issue of head) that you are perhaps trying to add up all of the piping and fittings for the entire project as if everything is in series, when in fact everything will be (or at least should be) in parallel. Parallel changes things massively, but also greatly simplifies the issue of calculating head. Each loop will have only its own unique head to be concerned about and calculated, and that goes for the primary loop, as well as each of the secondary loop/zones.

The primary loop will have height head plus friction head. The secondary zone loops will each only have friction head. Friction head only has meaning with respect to the GPM's that you require to move in each independent loop. You can not separate friction head from GPM of flow.

Have you tried the 'friction head' spreadsheet that I linked you to? Since you are already using 1.6 as your multiplicative factor by which to treat fittings as if they were straight pipe, just change my spreadsheets default value for this of 1.5 to your chosen value of 1.6 and you will be good to go.