Heating Large Shop in Alaska W/ Sequoyah Outdoor Boiler

Scottscoaled wrote:Sorry Larry. I was thinking more along the lines of if there isn't enough flow, then the Delta T would increase. Designing it for a 20 degree delta is fine. but if the water isn't moving fast enough,the delta will increase and still get quite a bit of available BTU's out of the water. It's the only way that every one could be using their OWBs with 1" pex and supplying bigger heat loads.

I agree! There is nothing magic about maintaining a 20 degree Delta-T. It only happens to make the math simple. But with charts, this is of no concern.

Scottscoaled wrote:Sorry Larry. I was thinking more along the lines of if there isn't enough flow, then the Delta T would increase. Designing it for a 20 degree delta is fine. but if the water isn't moving fast enough,the delta will increase and still get quite a bit of available BTU's out of the water. It's the only way that every one could be using their OWBs with 1" pex and supplying bigger heat loads.

Agreed. Those fan coils can pull a lot of heat out of the water.

Calculations on the heaters are correct. We shall soon (HOPEFULLY) see what they will do. If only I did not live 80 miles one way from the nearest store then we could find out sooner.... that along with work keeping gone for the next several weeks. Hopefully I can find some time to just get them hooked up and pushing some heat. It was after all -9 this morning. I did not beat the cold or the snow in my attempts to win against mother nature this year. She seems to always win. I will keep you posted once they are hooked up on the progress. Thanks for all the help.... I am sure I will need more in the near future.

AlaskaCoal1 wrote:Calculations on the heaters are correct. We shall soon (HOPEFULLY) see what they will do. If only I did not live 80 miles one way from the nearest store then we could find out sooner.... that along with work keeping gone for the next several weeks. Hopefully I can find some time to just get them hooked up and pushing some heat. It was after all -9 this morning. I did not beat the cold or the snow in my attempts to win against mother nature this year. She seems to always win. I will keep you posted once they are hooked up on the progress. Thanks for all the help.... I am sure I will need more in the near future.

AlaskaCoal1 wrote:So with all the comments about coming to Alaska when do I need to be at the airport"?

OH, so we just forget about getting any plane tickets now.

Well... I have finally returned from many business trips to long work days and things are slowing down. I am WAY off my timeline thanks to work making me travel and as with my good fortune the weather here is -20's to -30s so things are more difficult to accomplish. Here is an update on the shop temps

With no heat and a week of -5 to -20 the shop stabilized at 14 - 18 degrees. I am sure as this continues that will drop some. I took a reading today after three straight days of -15 to -30 and the temp in the shop was 14 degrees and the back of the barn that is unheated--- (remember 80 foot barn with only the first 50 feet as a shop) was -20. So I am happy with my insulation job.

I hooked up quickly in a small amount of down time the main loop to the shop and the heaters. All I did was hook them direct and it is forced to loop through the two heaters to get return to the boiler.... there is a bypass ball valve installed in the event I have to take the heaters down for some time... that way I can continue to circulate hot water to the boiler.

With this set up and the heaters running full tilt for a 4-5 hours on a zero degree Sunday with the barn starting at 18 degrees I was able to get the temps above freezing and even into the high 30's. Discouraged I was... but I account some of that to the fact that there is ALOT of mass there to warm up and that was hurting my results. Hopefully once that occurs I will be off to the races.... that is no SMALL task though.

The really discouraging part was the fact that the boiler could not seem to stay caught up with that minimal load. IF and I say IF the heaters were churning out 80K BTUs that should not even make the boiler grunt. I was able to get it to stay caught up with 180 degree water on speed one. By my calculation that is about 4 GPM.... speed 2 is 6 GPM and speed 3 is 8 GPM. On speed three it crashes pretty quick... like 1.5 hours or so and it is constant feeding .... I am HOPING that it is my set up and makeshift plumbing to just test the system before final install. If not then I am looking at literal TONS of coal .... high electric cost (.22 per KWh) here and basically standing at the boiler to feed it. I just feel I am missing something here. Gonna play with it on Friday to see if I can figure it out. My trouble shooting boils down to this

Lots of mass to heat not allowing for extreme temperature rise based on constant running
Heaters are not on a zone and able to cycle they just run flat out... they would anyway for now being that the barn is not up to temp.... this lack of ability to cycle puts a large demand on the boiler that would normally have a short rest to recover as most system should not run flat out for hours. BUT I would think just two heater pumping max of 80K it should last longer than it did.

On a good note--- when I did heat the barn to near 36-38 on Sunday after turning everything off it and with overnight temps around -15 to -20... it dropped to 20 degrees and stayed there through monday--- Tues dropped to around 16-17 and on Wed after three straight -20 to -26 is now at 14. Hoping the key to this is gaining some thermal mass.

One more note of interest. With the system in what I call idle mode... circ on speed one fans unplugged but still pumping through the heaters to keep from freezing I am getting a good 15+ hours on about 100 pounds of coal. I even got 30 hours off of 120 pounds of new coal with really good bed already established so maybe 30-40 pounds of previous load left over. That seemed high to me at first for idle... but there is a BTU loss just radiating off the heaters as the water circulates as well as loss from the pipe and such... just not sure what it is--- ordered a IR thermometer to help with delta T of pipes as I know many may ask what that is running... should arrive middle december due to the christmas load Amazon is experiencing.

Lots of houses are burning 3-6 tons each season,some are burning more, up to 10 tons.
You are heating a building much larger than most houses & in a much colder area than most members are heating.

Yes,you WILL burn TONS of coal to heat your shop.... 10+

If that surprises & shocks you or depresses you..
Then you haven't read many threads on this forum.

Windyhill--- I knew I would use a lot of coal but my concern is that I could use 15 tons and really not throw heat... tried to extrapolate some numbers the other day and came up with like 63 tons. I know those are WAGs ...... the real issue with the coal use is that the furnace needs feeding very often IF this problem persist. Now that is NOT something most people do... I hear all the time on forums that I heat home shop and garage feed twice a day and that is it. That is my issue with the coal consumption is I do not have the ability to be a slave to the unit since I work 10+ a day. I just really think I have to be missing something here.... the previous owner lives down the road and he was surprised as well. Heated his home garage and DHW ... always was 68+ in his home 55-65 in the garage and he fed twice a day--- sometimes three times on really cold spells -35 to -40 and used around 28 tons a year. My shop is much better insulated and about as large as his home. I guess we shall see--- these are guesses right now but just really surprised me that two small heaters made the boiler grunt.

Unless your coal has very low BTU's/lb., 15 tons is going to be much closer to the truth than 63 tons.

I also think that you are not accounting for the massive amount of BTU's required to bring your shop up to temp,that is a much larger load than keeping a set temp.
That is the reason why my shop t-stat is on a set & forget program. I tried setting it back 10* each nite,set it back up in the am...it took until noon to get the "comfy " feeling back again.
With my set & forget program,my shop is comfortable all the time,the heat ex-changers cycle on/off as needed.

Like AC said, in case anyone Didn't READ that--" I guess we shall see" Keep us posted AC.

freetown fred wrote:Like AC said, in case anyone Didn't READ that--" I guess we shall see" Keep us posted AC.

YES, FF, we will all quit posting until further approval .

jeeze WH, that's twice in this topic you've showed your true self.

freetown fred wrote:jeeze WH, that's twice in this topic you've showed your true self.

I do believe that I have only 1 time directed any thoughts at you,which was an off topic post... my fault...... but not 2 times as you claim.

I am sharing info as I have experienced with hydronic heating since 2006,you choose to degrade both lsayre & myself in saying that we did not READ what the OP posted.
We both read,we both understood,we both shared to him ,for him.

"If that surprises & shocks you or depresses you..
Then you haven't read many threads on this forum. "------------that was # 1 that kinda rubbed me--sorry if I misinterpreted. Yes I saw the smilie. I don't think I was degrading--just pointing something out. Point being, I think the poster (AC) has really done his homework & is looking for some positive feed back.