Pipeline Heat Loss

Use this free software -

http://www.pipeinsulation.org/

Did the software suggested by Guest help? If so, what is the conclusion? I'm curious.

My estimate for the 60000 BWPD case (I assume this is barrels water per day, gives reasonable 0.8 m/s in 18" OD pipe)

Heat to dissipate ~ 4640 kW. Average water temp 100°C, ΔT 100 - 38 = 62 K.

With this ΔT, heat loss ~ 1 kW/m² if you're lucky - roughly same as a domestic radiator with hot water temp 80°C, room temp 20°C.

That comes to pipe length at least 3.5 km. What does the software say?

Cheers.......Codey

you forgot radiation, which is starting to become high above 100°C.

Using traditional Trace heating formula's:

At no wind you will loose 1370 W/m, this is valid till approx 2.8m/sec, where you will go over from laminar flow to turbulent due to wind.

But in this case the pipe outer state is becoming very important.

Roughness, emissivity

What is the average background IR radiation?

Is a difference between day and night acceptable?

I would not do it this way, to much variables, to much things you don't have in hand.

To dangerous: Or do you make the investment to run 2 miles of HOT 18" pipeline in a safe way?

Good point about radiation. A quick calc shows just over 1 kW/m² at 373K. But unless the pipe is shaded it will receive about the same from the sun (though not over the total area, or for 24 h/day).

As the pipe area is 1.4 m²/m, your 1370 W/m is pretty much the same as my 1 kW/m². For trace heating calcs, wouldnt a high estimate of loss be used? I tend to use 1 kW/m² if I don't want heat loss (eg frost protection) and 0.5 kW/m² if I do (eg house radiator) for safety both ways, as it's not an exact science.

I was really trying to get over that it looks like a non-starter, unless the pipe has to run several miles anyway.

I'm still interested in what the web software says. I can't be bothered to get on it as when I tried it wanted me to register etc.

Cheers.........Codey