Just to clarify here, Bill is responding to issues regarding swamp cooling and its need for air exchange.
He's NOT addressing the need for and location of exhaust vents to effectuate Buckminster Fuller's design for the passive "chilling effect." I think Shannon's inquiry was about the size and location of vents for the passive "chilling effect" design. However, Shannon also will have swamp cooling, so it's a bit confusing. (And, because I have decades of experience with swamp cooling, I responded to a swamp cooling question in this thread, also. Which confused things further.) I'm not sure what effect swamp cooling -- and its need for exhausting the humidified air / air exchange -- might have on the Bucky Fuller passive chilling effect design's functioning. Maybe none. Maybe significant, since it introduces several other factors, including pressurizing the interior space by forcing in outside (now humidified) air which is going to quickly fall downward and want to exhaust out the vents low along the wall. And if you leave a door open for exhausting humidified air, you are setting up a different air- circulation pattern inside the structure and the passive-cooling effect may not take place at all. I really like the idea -- and I can't find at the moment who introduced it -- of using furnace filters over the exhaust vents to dust and insect-proof them. The dust issue there only arises during windstorms (also known as "dust storms" on the desert), which can arise at any time. When you have 40 mph winds whirling and gusting around your structure, the dust (fine grains of sand) finds its way in through any opening. So exhaust vents become windows for dust intrusion. And also for mosquitoes and other insects if the vents are not screened. Am hoping someone will test and report on Buckminster Fuller's "chilling effect" as a standalone cooling experiment. Adding swamp cooling introduces confounding factors, as does the suggestion of placing a tarp shade structure OVER the hexayurt. Using shade cloth for a shade structure should have no effect, since it pretty efficiently allows air (even winds) to pass through. I use it here in the New Mexico desert where we frequently have 45 to 60 mph windstorms in late winter / early spring and it survives them, whereas tarps do not (as they parachute in the winds. The Fuller passive chilling effect depends upon a path of unimpeded air flow downward from the sky through a chimney near the roof apex and exiting out through vents cut low along the walls of the structure. Block the airflow, or add more venting in other locations (such as an open door), or add forced air (from swamp cooling) and you disrupt the intended passive flow pattern in multiple ways and probably lose the Bernouli effect, also. Best, kenwinston On Aug 1, 1:26 pm, "Bill Wiltschko" <[email protected]> wrote: > I was remiss in not stating all of my assumptions. > > > > 1) Leaving the door open will exhaust moist air, keeping the humidity less > than 100% inside > > 2) Large vents (approaching door size) will also keep humidity less than 100% > > 3) If you want humidity WELL under 100%, down to 50%, you need active exhaust. > > 4) I do not have experience with passive exhaust near top of peak. > > 5) If you want to be dust-free AND cool, there must be no way for dust to > enter vents or door. This suggests active exhaust at about same CFM as swamp > cooler output. The only dust filter you need should be the mesh-like stuff > in the swamp cooler. > > > > Bill > > -------- Original Message -------- > Subject: Re: [hexayurt] Buckminster Fuller's Passive Cooling Effect > From: Tony Beletti <[email protected]> > Date: Sun, August 01, 2010 10:27 am > To:[email protected] > Bill, could you explain: > > "Cutting vents are not likely to work if your swamp cooler puts out over a > hundred CFM. Consider active exhaust at about the same rate as the swamp > cooler output." > > > > Thanks, > > > > TonyOn Sun, Aug 1, 2010 at 12:25 PM, Bill > Wiltschko<[email protected]>wrote:Cutting vents are not likely to work if > your swamp cooler puts out over a hundred CFM. Consider active exhaust at > about the same rate as the swamp cooler output. > > > > Bill > > > > -------- Original Message -------- > Subject: Re: [hexayurt] Buckminster Fuller's Passive Cooling Effect > > From: Shannon <[email protected]> > Date: Sat, July 31, 2010 3:00 pm > To:[email protected] > > > > I am willing to give this a shot. However, this will be my first hexayurt so > I will not have anything to compare it to. > I will also have a swamp cooler. > How many vents should I cut along the bottom you think? Maybe 2? > On Jul 31, 2010, at 12:02 PM, ken winston caine 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.... > > read more » -- 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.
