Re: [hexayurt] Exhaust for swamp cooler

[Dano McKagan]

Swamp coolers by evaporation, when water evaporates it cools off and that air is piped into the yurt.  The swamp cooled air will make the cooled area more cool and more moist.  Putting the swamp cooler inside will reduce it's efficiency.  Putting it outside will maximize it.  Unless I don't understand what your asking here.  With those winds be sure you can secure it.

For the exhaust I take you mean the air coming out of the yurt (as opposed to the cooled air coming out of the swamp cooler and entering the yurt)?  The swamp cooler will force pressure into the yurt and yes, you'll need some place for the air to come out to make it work.  Generally I think of putting the exhaust on the farthest side opposite the incoming cool air.  So if I pipe the air in close to the ground, the best exhaust port would be up high, which might be impractical.  Best would be to have the incoming air coming in very high on the roof and the exhaust being low, but that's impractical and inefficient too.

I'm still considering my incoming and outgoing ports.  I'm thinking of having it come in at the right elbow height to minimize the distance the cooled air has to travel out of the bucket.  And the incoming swamp air to be on the opposite side of a window.  I may cut a special round swamp cooler "window"/port into the hexayurt, I'm not sure, there are pros and cons to that.

All that said, I've only had a swamp cooler in a house.  This is my first in a yurt, and on the playa ta boot.

I did some cowboy math and came up with the standard H12 hexayurt to be approx 1000'^3.  (Anybody have a better number?)  Given the thread recommending 3-5 air changes/minute, I get the range the fan needs to push 200CFM-333CFM.  Higher would push more air in the yurt and increase the pressure in the yurt.  A little might be better, too much pressure would degrade performance, but I won't know for sure until I test it.

Dano!

On Thu, Aug 16, 2012 at 11:59 PM, Ray S <ray.se...@gmail.com> wrote:

Hi everyone.  This will be my 3rd year at the playa with a hexayurt and I've finally managed to build myself a swamp cooler (see Figjam's thread here:  http://eplaya.burningman.com/viewtopic.php?f=280&t=33842&start=1500 ).  I haven't decided if I'll have it outside of my yurt with the fan poking through a hole fit for it, or have it inside with a hole cut for the vent on the back of the cooler.. I'm figuring on trying both and see what works best.

My real question is, what should I do for exhaust?  I have an HVAC furnace filter which is around 16" x 22" or something around that.  I was thinking of cutting a hole for it on the opposite side of where I have my swamp cooler mounted, so I would hopefully get a cross breeze and passively exhaust out while the fan on the cooler is running.  The fan I'm using on my swamp cooler is the Endless Breeze which is rated at 900CFM on high, but I'll probably be running it on low or medium which I'd imagine would be closer to 300-600CFM.  Would there be enough pressure from this fan pushing air in to force air out the other side?  Maybe I should go for two exhaust windows?  I'm hoping someone out there has done something similar and can chime in :)

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[Chasomatic]

Last year I took a furnace filter 16x20x1 and cut it into 4 smaller pieces. I then took 4 6x8x1 picture frames and hot glued the filter material into the frame. Finally I cut 4 holes in the top of my dome (where they fit without impacting the roof structure) and pressed the frames in the holes.

This gave me great light in the day, and the passive ventilation worked great with my swamp cooler.

2011 I had a 30*f drop from outside to inside temperature (105 to 75).

 

A swamp cooler won't work if it's inside the yurt. Has to be outside.

 

charlie

[Ray S]

Hi Charlie,

What do you mean exactly by cutting 4 holes in the "top of your dome" ?  Do you mean you just picked 4 parts of the roof near the top and notched out holes to let this fit in?  This sounds like it would work great for passive cooling, but wouldn't this be a problem if it rained?

[Bill Wiltschko]

I put a 12v RV exhaust fan in the roof.  It required a ~12x12 hole.  If you don't have active, as opposed to passive, exhaust it will get really humid inside.  The RV enclosure has a lid that can be cranked open or closed.  The ideal fan speed produced negative pressure inside, but since the structure is already dust-proof, there was no impact from that. 

 

Bill Wiltschko

-------- Original Message --------
Subject: [hexayurt] Re: Exhaust for swamp cooler
From: Chasomatic <chas...@gmail.com>
Date: Fri, August 17, 2012 9:46 am
To: hexa...@googlegroups.com

Last year I took a furnace filter 16x20x1 and cut it into 4 smaller pieces. I then took 4 6x8x1 picture frames and hot glued the filter material into the frame. Finally I cut 4 holes in the top of my dome (where they fit without impacting the roof structure) and pressed the frames in the holes.

This gave me great light in the day, and the passive ventilation worked great with my swamp cooler.

2011 I had a 30*f drop from outside to inside temperature (105 to 75).

 

A swamp cooler won't work if it's inside the yurt. Has to be outside.

 

charlie

On Thursday, August 16, 2012 11:59:19 PM UTC-7, Ray S wrote:

Hi everyone.  This will be my 3rd year at the playa with a hexayurt and I've finally managed to build myself a swamp cooler (see Figjam's thread here:  http://eplaya.burningman.com/viewtopic.php?f=280&t=33842&start=1500 ).  I haven't decided if I'll have it outside of my yurt with the fan poking through a hole fit for it, or have it inside with a hole cut for the vent on the back of the cooler.. I'm figuring on trying both and see what works best.

My real question is, what should I do for exhaust?  I have an HVAC furnace filter which is around 16" x 22" or something around that.  I was thinking of cutting a hole for it on the opposite side of where I have my swamp cooler mounted, so I would hopefully get a cross breeze and passively exhaust out while the fan on the cooler is running.  The fan I'm using on my swamp cooler is the Endless Breeze which is rated at 900CFM on high, but I'll probably be running it on low or medium which I'd imagine would be closer to 300-600CFM.  Would there be enough pressure from this fan pushing air in to force air out the other side?  Maybe I should go for two exhaust windows?  I'm hoping someone out there has done something similar and can chime in :)

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[Alejandro Moreno]

I would think you'd want to alao take into consideration the fact that cold air falls and hot air rises. Given this, the cold air inflow into the yurt should come in up high so that you get maximum cooling. And since hot air rises, likewise the exhaust should be up high as well since that is where the hot air ends up. Of course, locating them on the walls would be the best to prevent rain problems/leaks etc. Though I could see a well sealed input being placed on the roof (but not the exhaust).

Sent from my iPhone

[Ray S]

Hi Bill,

Your suggestion is intriguing.  I like the idea of having a vent in the roof that opens or closes with a hand crank.  Have you had any issues with water leakage in yours (or has water even been tested with yours)?  Also do you put any filters on it as well so when it is open your not letting dust in?  Perhaps with just the pressure like your saying, air / dust wouldn't come in there anyway so this wouldn't be a problem?  I'm more curious on the water sealing of it, as I want to be prepared for rain :).

Any recommendations on cheaper RV exhaust units that have airflow up to 500-900CFM?  (As this is probably what I'll be cranking with the Endless Breeze I'm using with my swamp cooler).  I was looking through Amazon but wondering if you had any you prefer.

[Bill Wiltschko]

I don’t remember whether it rained the two years I had the vent, but it overlaps the hole in the roof so as to present a minimal problem.  Also the fit it tight and I do not seal it.  Btw, the RV fan is about 750 cfm on high speed, using about the same power as the swamp cooler fan.  I think I have a “Fan-tastic” fan.

 

I have given up on filters.  The first couple of years on playa with the hexayurt I had furnace filters in many places.  They are now all gone.  I effectively have one filter now, the porous thing in the TurboKool swamp cooler against which the water is thrown by the fan/pump.  It gets dirty after a week, but most of the dust sinks down to the bottom of the shallow reservoir from which the water is pumped – in other words it’s nearly self-cleaning.

 

Bill Wiltschko

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[Chasomatic]

I put them in there spaced one filter every two panels. They were about a foot down from the peak but I didn't even think about it raining actually but it worked beautifully with the positive inflow from the swamp cooler. A nice feature is the fact that the filters didn't interfere with me folding up the panels.

[Chasomatic]

Ray,
I used a very similar swamp cooler, the Home Depot bucket, but I had a lot more holes in the bucket probably The top half of the bucket was holes, this gave me a lot more airflow and I think it made my cooler much more efficient. I also put in a standoff of pipe insulation on the inside of the bucket, I then placed my blue filter media against the standoffs and it kept the wet media from rubbing against the outside of the bucket this eliminated any water exiting the bucket through the holes. The standoffs were tubular hot water pipe insulators and I cut them to fit the inside of the bucket and placed the media against it. I hot glued these rings of standoff material against the side of the bucket.

[Cody Firestone]

FROM THE ARCHIVE

ken winston caine

Post reply 7/31/10

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: hexa...@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 <spiral...@gmail.com> 
wrote:

kenwinston caine

Post reply 7/31/10

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" 

- show quoted text -

> Here's a Google Books link to that page:http://books.google.com/books?id=2rPqFvn3nocC&pg=PA211&lpg=PA211&dq=b... 

- show quoted text -

> On Fri, Jul 30, 2010 at 2:45 PM, Spiral Syzygy <spiralena...@gmail.com> 
> wrote:

Tony Beletti

Post reply 7/31/10

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

- show quoted text -

- show quoted text -

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ken winston caine

Post reply 7/31/10

Re: [hexayurt] Buckminster Fuller's Passive Cooling Effect

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

[The Distinguished ...]

Greetings,

On Sun, 2012-08-19 at 04:52 -0400, Cody Firestone wrote:
> FROM THE ARCHIVE

>
>
> 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?

Thank you for reminding me.

I went back to the builder, from whom I had heard about them long since,
to ask about them. They were used in mosques in Cordova, which was then
part of al-Andalus, in the 10th century, in places where they had lots
of heat, but not much dust (or, apparently insects, or didn't care about
the insects ...) and were carved stone, or stucco (or possibly wood, but
we have no record of those anymore) my test showed that, indeed, moving
air (generated by a fan, pointed sideways, aka not at the window) was
cooler on the smaller-holed side than it was on the larger-holed side
(the side with the fan on it) using identical thermometers. (I switching
them, to make sure it wasn't a function of the thermometer, or my
ability to read it.)

I also did a form of the vent test, with an actual ger (what most people
call yurt) which I live in for Pennsic every year. Having vents
(basically lifted cloth) at the bottom, around the house, and having the
roof-hole open, or with a chimney from the roof-hole upward (we tried
both ways) had it much cooler in the ger, yes, but a piece of cellophane
hung from a pencil showed air moving _in_ through the vents, and out
through the roof hole or chimney, not vice-versa.

Percival