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How many BTU's through 1/2\" Kitec?

Member Posts: 186
The rate of thermal conduction through this pipe is;

0.457 BTU/hr/Ft/deg-F

CoEfficient of Thermal conductivity:

3.12 BTU/h/Ft/in./Deg-F (0.45 W/m x Deg-C)

• Member Posts: 2
How many BTU's can I get through a 1/2 pipe?

I have 4 runs of 1/2" Kitec running 50 feet to another building. I need 38,000 BTU's in that building. I could use 2 for the supply and 2 for the return.

Is this piping big enough?

Thanks so much for your help.

PS. My required temp in the outbuilding is 160 degrees.
• Member Posts: 85
pipe

I think around 17,000 btu for the 1/2" & 27,000 for the 3/4" cooper .
• Member Posts: 2,322
Typically

You can get 1 gpm through 1/2" pipe before encountering nasty head problems. Using that as a guide you can calculate the btu's using the temp drop you have designed for. So............ It depends

1gpm x 2 pipes =2 gpm

2 gpm x 8.33 x 60 = 999.60

999.60 x (your temp drop) = total btu's delivered
• Member Posts: 81
You are cutting it really close........

Given that you only have 50 feet to travel, and I am assuming it is well insulated along the way, or is enclosed and insulated so as not to loose much heat.

You should be able to pass 2 gpm per tube in only 50 ft.
This would give you 2gpm X 20 deg (delta T -- assumed in the out building) X 500 = 20,000 btuh per tube.
Two tubes X 20K each = 40K btuh..
Not much to spare as long as you have 4 gallons circulating within the 2 tubes and a delta T of 20 deg F.

Sometimes it is just good to be lucky!!!!!!

Good luck --- Alex
• Member Posts: 2
OK

The ditch was dug and the pipes were in when I showed up. IF it doesn't work I can always go to plan B which is to put in a ditch and 1" line direct to the boiler (woodfired).

I knew those numbers. I just really needed to have a second opinion.

I am going to put it in. If it works then great! If not, then on to plan B at the customers expense.

Did I mention the customer is my father-in-law and 2 brother-in-laws? That is why I was too ashamed to use my real name. Because I am busily violating one of the 10 commandments of hydronic heating. And i am already paying for it. You cannot violate that commandment and get by. LOL

THANKS to ALL of you.
• Member Posts: 6,106
25,000 easily

perhaps a tad more as Kitec has a larger ID than most PAP. 36,000 per tube if you run a 30° delta T.

As far as how much energy you will get, that depends on the loss to the dirt between the buildings. the colder the ground gets the higher the delta T and the greater the loss to the soil

hot rod