Unit Heater vs. Steam Coil 1

[yasernoman]

On our project, a choice between a Unit Heater vs. Steam Coil for heating an Aircooler bundle is required. I was not really clear on how a Unit Heater works to heat the aircooler tube bundle. Any explanations?

 

[SNORGY]

You just want to prevent the lower tube pass from freezing or plugging due to hydrates, so you add heat to the local air space below the bundle. Unit heaters can work if strategically placed, albeit inefficiently. I have used electric Ruffnecks for this winterization strategy with success. I just put a small skirt around the perimeter of the bundle below the fan deck to help contain (crudely) some of that heated air. My experience has been, however, that if you are already in a scenario where you need to add heat, you are either shut down completely or operating in a mode where closing the discharge louvers on the cooler and running the fans in a push-pull (one fan running backwards; VFD on motors assumed) arrangement might be enough without going to a full warm air recirculation system (per the old API-632).

Steam works, as does heat medium glycol, if either are available, but be prepared for the swings in demand when you start putting heat to the cooler, particularly if for an extended period of time. Pay attention to tracer circuits at far ends of tracer loops / headers / sub-headers.

Regards,

SNORGY.

 

[Ziggypump]

Careful with steam in any area where freezing can occur. The condensate can freeze and create all sorts of problems with your system. I've heard horror stories regarding the use of steam piping in the outdoors.