BTU per foot of tubing

Mike Young_2

Can someone please refresh my memory... How many BTU's can travel through 1/2", 3/4", and 1" copper tube if water temp is 180 degrees. Where can I find a table on this?

Unknown

Someone posted this not long ago, perhaps it fits the bill?

Dave

Steve Ebels_3

What Dave said

Use that chart and you won't go wrong. Be mindful though that output varied with not only entering water temp but also the actual temp drop you can achieve in that loop.

SpeyFitter

Feet per Second?

Now can someone relate to me how gallons per minute translates to feet per second?

Only reason I ask is the German Polypropolene pipe the company I work for uses and I sometimes install offers EXCELLENT flow rates, much better than Copper for domestic water and heating, so much so that you can go from the traditional 4-5 feet per second to 8 feet per second for domestic water which really reduces the size of pipe you need.

hot_rod

higher flow rates

can lead to erosion corrosion problems, especially at the fittings. Maybe the pipe is happy with higher velocity but ells and tees may not.

Depends too on the fluid, hard water, aggressive water can add to problems.

Oversized DHW recirc pumps are a common problem of pin holes and erosion problems in piping. Un-reamed tube makes the problem worse

There are guidelines and tables for sizing piping, both potable and hydronic applications.

A smoother interior walled tube may allow higher velicities, but don't forget the fittings.

hr

hr

hot_rod

Pipe sizer program

this program allows you to modify the delta t, and other parameters like temperature, fluid, pipe material, etc to show the difference in BTU carrying capacity.

Notice in this example how a larger delta t allows 3/4 copper to carry 105,000 BTU/hr.

It's common in Europe to see panel radiators fed with @3/8 tube size, by running a larger delta t.

hr

Steve Ebels_3

Plus the fact

That smaller tube means higher pressure to achieve a giving volume of flow regardless of whether you are talking hydronic or domestic plumbing. It's a tit for tat thing.