🚀 go-pugleaf

In article <gordon.722277803@tramp.Colorado.EDU> gordon@tramp.Colorado.EDU (GORDON ALLEN R) writes:
>rbw3q@rayleigh.mech.Virginia.EDU (Brad Whitehurst) writes:
>>>
>>	Quite a lot of solar heating systems were/are set up that
>>way.  They are not as high performance as forced circulation, but
>>then, they don't have all the hardware, either.  The cooling systems
>>in some old engines were thermosyphon also.  And any process where you
>>are heating a vessel from the bottom could exhibit this behavior,
>>couldn't they?  (you'd have convection cells, rather than water
>>running in a pipe, though)
>
>A couple of fairly recent applications include some very inexpensive solar
>hot water systems, that circulate heated water from the collector to the 
>storage tank by virtue of the convective effect.  

	Actually, that kind of solar heater has been popular since the
late '60s for pool heating and household hot water, esp. in the solar
heyday of the oil embargo era.  (Remember those fun Whole Earth
Catalogs??)
>
>There is a device that uses heat from a wood stove to heat water in a coil
> that rises to a special condenser above the stove.  The heated water then 
>circulates around a closed heating loop and back to the coil in the stove.
>
	Also the "heatilator" fireplace inserts.  Some are fan driven,
and some are passive.

>Its all 'passive'.  Is not the old coffee percolator an example of this effect?

	Actually, a percolator cheats.  It has a check valve in the
stem of the basket.  Also, it may depend on a little local boiling to
get a 2 phase flow.
>
>allen
>-- 

Brad

-- 

Brad Whitehurst    |   Aerospace Research Lab
rbw3q@Virginia.EDU |   We like it hot...and fast.