The hot-air updraft exists around any building in the sun -- especially on the more southern faces. Doesn't matter whether you have the floor exhaust vents or not.
The floor vents will contribute a bit of interior exhausted air which most likely will be significantly cooler than the exterior air. And, if you're running a swamp cooler inside, that exhausted air will be much more moist than the outside air. You don't want to directly feed humid air into the swamp cooler or you'll decrease its efficiency. So I would offset its mounting location of the swamp cooler from the floor vent location to give the outside hot dry air a great chance to evaporate the moisture being exhausted via wall vents just in case any of that air is being sucked up and into the swamp cooler. Probably best location for swamp cooler is on a north-facing wall where it will be shaded much of the day. And my experience with swamp coolers (extensive from most of a lifetime of desert living) is that higher the thing is located, the better the cooling effect and dispersal of the cooler, moist air. It settles fast (unless you are in a humid climate or don't have exhaust vents to exhaust the humidified air). Window mounted units tend to work just fine -- as well if not better than roof -mounted ones. Except that roof mounted ones have exposure and air intake on all four sides and the good, big window units only draw in on three sides. So you lose 1/4 of the cooling ability. OTOH, the lower you mount the unit on a north wall, the more it will be shaded from the sun much of the day. Still I would mount it with the top at at least at neck level when standing -- if it's a powerful and effective swamp cooler. If it's weak, then face level at whatever position you are going to be in most inside the structure. Having cool air on the face provides the sense of coolness, even when the rest of the body is hot. My thinking. Always subject to revision. -- kenwinston ----- Original Message ----- From: Tony Beletti To: [email protected] Sent: Saturday, July 31, 2010 2:08 PM Subject: Re: [hexayurt] Buckminster Fuller's Passive Cooling Effect I plan on building a 1V dome at BM this year. It'l be a wood frame, vinyl-clad structure with 1.5" rigid foam insulation boards cut to fit inside each wall and roof triangle to help insulate and reduce noise. I may experiment with this cooling effect. I was originally planning to vent hot air via fan through the peak of the roof and use my diy evaporative cooler at the floor to bring it cooler air. Instead, I could install those 4" or 6" screw-open/closed white ceiling vents, one on each side of my structure near ground level, to allow for hot air to be vented out and remove the exhaust fan from the roof vent and let cooler air in that way. I'd then have to relocate the inlet for the evaporative cooler. Not sure if ceiling or higher on a wall would be recommended over low near ground level. Any advice on that? If a hot air updraft is in fact created along the exterior walls of the structure, I may also elect to move the evaporative cooler away from the structure's exterior by 2-3 feet to reduce the warming effect that the hot air might have on the water/air in the evaporative cooler. Tony On Sat, Jul 31, 2010 at 2:02 PM, ken winston caine <[email protected]> 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=buckminster+fuller+chilling+effect&source=bl&ots=refmEA3ApA&sig=3MMsUUMp4QPWIhFAdLciDRULC4w&hl=en&ei=SGxUTPamF4G78gbO19SpBA&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBYQ6AEwAA#v=onepage&q&f=false 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: [email protected] 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 <[email protected]> wrote: -- You received this message because you are subscribed to the Google Groups "hexayurt" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/hexayurt?hl=en. -- You received this message because you are subscribed to the Google Groups "hexayurt" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/hexayurt?hl=en. -- You received this message because you are subscribed to the Google Groups "hexayurt" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/hexayurt?hl=en.
