As "Critical Path" reference noted, another reason this cools air is the "Bernouli" effect of speeding the air -- as a fan does, and as Percival alluded to in his mention of ancient stone window cover designs (which I'd like to know more about!) here, in this thread: http://groups.google.com/group/hexayurt/browse_frm/thread/3108984409d21ac5?hl=en#
Percival, if you see this, can you tell me what those stone window covers were called so I can research them a bit? On Jul 31, 1:02 pm, "ken winston caine" <k...@mindbodyspiritjournal.com> wrote: > Has anyone experimented with Buckminster Fuller's repeatedly demonstrated > passive "chilling effect?" (Sometimes also written about as the "cooling > effect.") > > He accomplished this with a chimney in the center of the roof (with a vent > flap which could be opened and closed), and with a series of wall vents just > inches to a foot above the floor all around the building -- those vents, > too, could be opened and closed. > > As the sun rises, all the vents are opened. Heat reflecting off the ground > and off the building create an updraft all around the building. This updraft > draws air OUT of the vents just above floor level. (It appears to me that > these vents often were about 1 foot off the floor -- and that in total, they > exceeded the volume, by at least 8::1 or greater of the volume of the > chimney vent.) > > As air is sucked out of the bottom vents by the updraft around the building, > air is drawn in through the chimney. > > Fuller said the chimney downdraft effect extends hundreds of feet upward > into the air and draws down a much cooler air than is found closer to the > ground. > > He demonstrated this effect in equatorial desert regions with domes equipped > as described above. But, the dome shape was not a significant factor in the > "chilling effect," he said. > > This "chilling effect" was also implemented in Fuller's "Dymaxian Home," > which somewhat resembled a hexayurt. (Do believe that it may work best in > quasi-round buildings -- which the hexahurt is.) While Fuller promoted the > cooling effect in hot climates, he also promoted the same process as a > "self-cleaning" effect. > > Because this effect creates a cool downdraft and floor-level exhaust, it > tended to draw out most of the ambient dust from the house, reducing the > need for frequent cleaning/dusting. > > In Fuller's demonstrations -- in both humid Kansas summers and in equatorial > deserts -- indoor temperature was lowered by about 15% after opening the > events and setting up the "chilling effect." > > People reporting on the experiments frequently noted with amazement the > sensation of cool air falling on them when they walked into one of the > demonstration buildings. > > Fuller wrote, in what may be his last book, "Critical Path," on page 212 > that the " pressure differential between the small air entry and large > exhaust openings produces the Bernoulli chilling effect, which in hot > weather will swiftly cool the ... interior." > > On that page he also provides a drawing of how it works with a geodesic > dome. > > Here's a Google Books link to that > page:http://books.google.com/books?id=2rPqFvn3nocC&pg=PA211&lpg=PA211&dq=b... > > You can read more about the effect in these two books also: > > Air Cooling Tendency > Buckminster Fuller's Universe pp 208-09 > And Chilling Effect > BuckyWorks pp 114, 116 > > This is all counter-intuitive, I know. We all "know" that heat rises and > that you need to vent it via an updraft at the highest point in your > building. But not if you want to enjoy Buckminster Fuller's "chilling > effect." > > In that case, you want to out-vent via convection at a low point all around > the exterior of the building, and actually draw in a downdraft cool column > of air from much higher in the atmosphere through a chimney at the peak of > the roof. > > Fuller explained somewhere -- and I can't find my old notes at the moment -- > that a column of hot air rising from around a circular building actually > creates a downward vacuum in its center that pulls cool air down through its > middle. > > I asked a couple years back if anyone would demonstrate / experiment with > this at Burning Man and report here their experience, but found no takers > then. > > How about this year? > > I would think that for the Playa, you would want to cover the vents with a > filter material, such as the cheap blue synthetic stuff used for swamp > cooler filters now that they rarely use straw any more (because of its > tendency to grow mold). That way, during dust storms, it would be unlikely > that you would experience much dust intrusion. Or, you might set up another > simplie way to block the vents during periods of extreme blowing dust. > > In my original experimental designing with this, I found located some dollar > store air-filled plastic balls (bouncy balls) that would perfectly fit > inside 3-inch pvc pipe. So I created a design using pvc pipe for the floor > vents and the balls to seal them closed. I also drew into the design pieces > of fiberglass insect screen crudely tied around the outside openings of the > pipes. (The pipes fit through the wall panels and extend a couple inches > beyond the wall on both inside and outside -- though could be cut to mount > flush for a neater install.) > > And for the roof vent, you can use a capped stovepipe and a damper flap > section. The damper flap can be used to close (and open) the roof vent. Or > just use another piece of pvc pipe and plastic ball and buy a $2 sewer-vent > cover at an > RV supply joint for a rain cap. > > Or, you could go even lower tech and just cut vent holes and save the > cut-out material and stuff it back in and tape it in place to close the > vents. > > I remain astounded with how this "chilling effect" works and, even more, > that about 70 years after Fuller first began demonstrating effective, > passive air conditioning drawing cool air from hundreds of feet above ground > that it is NOT being designed into buildings in warm and hot areas > worldwide. > > This MAY be because it works best in quasi-circular buildings (if that is > true), and conventional design does not use round buildings. > > Do believe that it was engineered into the early sports domes. > > And I know that there is an emphasis since the late '70s on airtight, > sealed, stale-indoor-air-filled, atmosphere-controlled buildings (which this > is the opposite of) for energy efficiency. > > Anybody up to testing / demonstrating this at Burning Man this year? > > If you do, would you report on it here? Maybe shoot a video with a > thermometer demonstrating temperature with vents closed, after an hour with > vents open, and of the outside air temp? Then, for all time, everyone could > *see* the results in action. > > Best, > ken winston caine > > > > ----- Original Message ----- > From: William Ozier > To: hexayurt@googlegroups.com > Sent: Friday, July 30, 2010 3:53 PM > Subject: Re: [hexayurt] Insulation Thickness > > I am going to try and create a solar chimney on mine to help keep it cool. > You put a black tube coming out the top. The sun heats the tube which heats > the air and causes an updraft, which vents out the hot air and pulls in cool > air...of course finding cool air to bring in on the playa maybe difficult, > so there are a few more details to be worked out. > > On Fri, Jul 30, 2010 at 2:45 PM, Spiral Syzygy <spiralena...@gmail.com> > wrote: -- You received this message because you are subscribed to the Google Groups "hexayurt" group. 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