Heating

You'd need a spool of heat tape a mile long to get 36kW, Guv. I haven't got enough for yer at the moment. The problem is keeping the damn thing below 200F. What in Aveley's name are you doing, fer Pete's sake? <Cough, splutter>

If i was supposed to care about price, I'd go for resistive heating with thermostat. And allow the tube heat conduction do the rest. If I'm not worried about cost, go for an inductive system with different circuits and sensors, controlled by PID. Inductive heating is somewhat easy to control because you can adjust the electric source parameters easily. Oh, ok, I said its easy, not cheap.

Just a bit tough ?

3/4" tube, 2' long, guzzling 36KW and then where does it throw it out ? to maintain the temperature to 200^oF max ? I will love to have this for my heat exchangers where even 10-12KW requires 3/8" copper fully finned tubes and a lot of them.

Or it is just to heat it to this temperature and then reduce the power to maintain the temperature ?

I will go usually with the Inductive, but the cost may be a bit high as bhr said. But maintaining the temperature may have too fast switching anyway.

Yeah. You tell 'im. <Splutter>

That's about the same size as an immersion heater element, Guv, and they're rated at only 3kW. You want 36kW and to keep its temperature below 200F? Strewth! you aren't half going to need some turbulence past it! <Cough, splutter>

A back-of-the-envelope calculation would indicate that it is not possible to transfer this amount of heat without increasing the surface area of the tube many times, as sb has already correctly pointed out.

Further, the nature of the fluid in contact with the pipe is not stated. Fluid properties will have a substantial impact on the heat transfer operation.

More likely above 2000°F at this power.

Direct heating preferred.

RHABE