Sizing underground lines

[canmic]

Ok, I've read the sticky and taken a look at the Taco page etc.. and I am trying to figure out a couple of things:

1) If the boiler (250kbtu) is out in the workshop (120 feet from the house) and the storage is in the house, what would the delta-T be for the calculations of flow rates etc? I'm thinking 5 degrees at most to be able to get the storage up as hot as possible? For running the load, sure, 40 degrees works, but that won't heat up the storage to a usable temp.

Problem is, that gives 100 gpm as the flow rate! That sounds pretty darn high

Should I be using the average delta T instead of the minimum? I'm thinking that the boiler BTUs will be highest at the beginning of the burn (once it gets really going), when the delta T will be highest because the storage is coldest and then the BTUs will drop as the fuel gets used up and the storage heats up.

Using the average delta T (20 degrees) works out to a much more reasonable 25 gpm.

2) Looking at the Taco calculations, they base their maximum flow rates on keeping the pipes quiet in an occupied space. Obviously no one cares if pipes that are a couple of feet underground and wrapped in foam are noisy. Can those pipes be a bit smaller and then when the pipes enter the house, step up the pipe size a couple of notches to keep it quiet inside the house?


Is anyone running a 200-250 kbtu boiler outside with storage inside? What sort of pipe sizes and flow rates are you using?

Thanks!!

 

[canmic]

I think I solved the height problem!! I can put the boiler inside the house after all

 

[JP11]

I think I solved the height problem!! I can put the boiler inside the house after all

I think my 0011 runs about 22 to 25gpm off 1.5" piping to storage that's only 15 feet away. Seems like my delta t is usually 12 to 15 degrees when it's going good. So that's my 200k BTUs.

I wish I had a flow meter to really tell.. but that's just the dial reading geek in me.

JP

 

[canmic]

I think my 0011 runs about 22 to 25gpm off 1.5" piping to storage that's only 15 feet away. Seems like my delta t is usually 12 to 15 degrees when it's going good. So that's my 200k BTUs.

I wish I had a flow meter to really tell.. but that's just the dial reading geek in me.

JP

Do you have a temp guage on your storage?

If so, you can work backwards by knowing the BTUs that you have moved over a set period of time and then figure out your flow rate, keep the time interval short so the delta T doesn't really change much or you can go with a reasonably long but not too long interval and use the average delta T and pretend it was a straight line instead of a curve, it's mostly straight if the tank is starting "cold".

 

[JP11]

Good Idea. I'll give it a try.

Dang circulator on my DHW went. Of course I'm in chicago.. and don't get home till thurs.

Plenty of heat in the tanks.. but no way to get it thru the DHW coil. Oh well... plumber coming tomorrow.

JP