re: duct basics
13 sep 2003
don ocean wrote:
>>...don't go above 400 feet per minute, to keep fan power low. big ducts,
>>or no ducts at all, just open doors and stairways and floor grates and
>>slow ceiling fans, if not thermosyphoning. work with nature, not against it.
>>put heat returns near outside walls in wintertime, and so on.
>ummm? wouldn't 200 feet per minute be a bit better?
sure. bigger ducts. less fan power.
>do you really want that kind of toss on a floor register for heat?
>heat rises naturaly to the ceiling without that additional kick.
cool air near exterior walls falls in wintertime, where it makes sense to
collect it in floor returns, as harry thomason did. warm air rises, so it
makes sense to supply it near interior walls, with a low heat source and
a high vent at the top of some sort of warm air column, eg a closet.
>a properly designed/engineered system would not require ceiling fans.
an engineered thermosyphoning system with no blower might have an ac coil
behind a high return over a column of cool air. a properly-designed criminal
system with a unidirectional noisy power-hog blower brutally pushing cool air
out of high vents might have a slow ceiling fan to stir the air in the room
and keep occupants cooler.