cooling your tent or van

Swamp Coolers, Cooler Management, Dry Ice, Misting Systems, and just plain how to beat the heat.
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willyd
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Re: cooling your tent or van

Post by willyd » Mon Aug 12, 2019 9:21 am

I am just speculating here, but imagine other factors that would affect comfort in the tent when it's in direct sunlight are:
- how well the tent material blocks radiant heat from the sun
- where your outlet vent is located

anotherperson
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Re: cooling your tent or van

Post by anotherperson » Mon Aug 12, 2019 9:27 am

Thanks FIGJAM and willyd

willyd, we got a canvas bell tent (here https://stouttent.com/shop/stout-bell-t ... o-edition/). there are vents at the top, but they are too small, so we'll likely open the door/window opposite the vent in from the evaporative cooler

hard to say if it'll be enough!

Ano
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Re: cooling your tent or van

Post by Ano » Mon Aug 12, 2019 9:43 am

Your mileage will vary drastically.

In 2013, I was able to use a Kodiak tent, sans shade, with a bucket cooler, and it was comfortable. We could nap mid-day. The trick was, it took a few minutes for the tent to cool down, and we had to sleep naked and with no covers, with the cooler blowing directly on us, but it did kind of work. Also, weather was mild.

However, every year since then, we've done shade. And the shade is a serious help. Tent underneath a carport with double-layered roof = goddamn luxury.

So, your answer is, maybe, could work, but it would work better with any kind of shade.

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Canoe
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Re: cooling your tent or van

Post by Canoe » Mon Aug 12, 2019 11:41 am

willyd wrote:
Mon Aug 12, 2019 9:21 am
I am just speculating here, but imagine other factors that would affect comfort in the tent when it's in direct sunlight are:
- how well the tent material blocks radiant heat from the sun
- where your outlet vent is located
No matter how well the material reflects heat from the sun and from sun-baked objects (i.e. ground), it will absorb a portion, some materials more than others, and more again when it's dusty. That heat gain will result in heat radiating at the occupants, and in heating the air.

If you have anything near the tent that can block heat radiated from anything sun-baked, that helps (particularly if there's a hexayurt reflecting at you). A vehicle parked as close as practical to the E or SE will provide some benefit in the morning.

To avoid making holes in a roof, most people vent/exhaust out the side. As hot air rises, get rid of the hot air gathering at the top of your shelter (and remove the heat absorbed by the roof soonest) by running a length of ducting (flex dryer duct?) the size of your exhaust, up to the top of your shelter (tie it or tape it), so the exhaust is removing the hotest air inside your shelter.
Gives you greater bang for your swamp-cooler, as the exhaust flow is removing more heat.
.
The diagram below was done for a hexayurt, which is insulated, but applies for anything that doesn't already have an exhaust vent at/near its peak.
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Image
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Less of a heat source, but still contributing, is sun-baked ground next to your shelter. That heat conducts through the ground and comes up from below. Anything you have on the ground next to the tent so it covers/shades that ground, helps the playa under the tent stay at un-baked temperatures.
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lavamatrix
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Re: cooling your tent or van

Post by lavamatrix » Mon Aug 12, 2019 3:20 pm

FIGJAM wrote:
Tue Aug 06, 2019 6:26 am
I would just set the intake of the cooler against the 12" hole on the inside of the pod.

If that hole doesn't have mesh, go outside and tape the edge of the hole to the vent panel to keep it sealed.
Do you think the 12" hole will be enough of a surface area to cool the air being pulled by the endless breeze? Does it make sense to double up the pad to make it twice as thick?

There are two 12" exhaust ports with the shiftpod, image attached. Thinking I can just have a 12" HVAC collar on the unicooler that maries onto one of those ports and then use the cinch to keep it tight and limit the dust and hot air that leaks in. Wort case I have a 12" flexible duct that I can use but I'd rather not use it so I can return it to HD and save some money.

@ Canoe, thanks for that great info. I thought about doing the inner U pad but was also worried about maintaining a tight seal so no hot air bypasses the pad. I'll have a think about if I can pull that off otherwise I might just gamble on the single pad and hope that is enough surface area to work. Since there is another exhaust port in the Shiftpod I think I will make a new bucket cooler (gave my old one to a campmate) as a second cooling source in case my unicooler isnt enough on its own. I have all the parts for a new one any way and with my solar panel and jackery battery I am not worried about drawing too much power running two coolers.

Thanks guys.
shiftpod_ac_and_power_port.jpg
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Canoe
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Re: cooling your tent or van

Post by Canoe » Mon Aug 12, 2019 7:16 pm

lavamatrix wrote:
Mon Aug 12, 2019 3:20 pm
There are two 12" exhaust ports with the shiftpod, image attached. Thinking I can just have a 12" HVAC collar on the unicooler that maries onto one of those ports and then use the cinch to keep it tight and limit the dust and hot air that leaks in.
I like that!
Even have a grove in the collar for the drawstring to tighten into.
Looks like you have 3+' below those.
Cooler is inside. Refill/control without having to go outside.
To stop dust (or the rare rain) from blowing in, possibly a 45 or 90 degree down turn ($), or a box over the collar on the outside (cheap)(stucco tape?). The typical intake grill?
Consider having something to cover the intake on the outside when you shut it down and go out exploring BRC.

lavamatrix wrote:
Mon Aug 12, 2019 3:20 pm
... I thought about doing the inner U pad but was also worried about maintaining a tight seal so no hot air bypasses the pad. ...
It can be done, but it's a real B..

A much easier alternate, is an adapter inside the unicooler, over the 12" intake hole, providing a larger area for pad. You could even go for as much pad area as the box-cooler, all in one vertical plane. Easy to mount, easy to irrigate. Just depends on the cooler box you use to have the space. You'll have an Endless Breeze to pull the air in with, uni-cooler or box-cooler, it won't care.
Canoe wrote:
Mon Aug 05, 2019 10:47 pm
...
Easier to build and have a seal, would be to have:
  • the box inside,
  • the 12" collar duct coming in from outside (short, insulated, etc. as appropriate)
  • inside the box, mount over and encompass the duct opening with:
    - build a box for the 12x16 (or larger) like a window rough-in (only 1" or 1/2" wood is fine), or
    - find a plastic storage box that is large enough on the bottom for the area of pad you want, which will be large enough for its top to fit over the duct intake, then cut the bottom out for your grill opening,
  • mount and seal the rough-in/plastic-box to the inside of the box - encompassing the duct opening,
  • install a grill on inside open-side of that rough-in/plastic-box, grill slope to the inside to keep water on the pad,
  • install the pad on the grill.
[/list]
Or some variation of that.
Video games are giving kids unrealistic expectations on how many swords they can carry.
.
... but don't harm the red dragon that frequents the area from time to time. He and I have an agreement.

lavamatrix
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Re: cooling your tent or van

Post by lavamatrix » Tue Aug 13, 2019 10:21 am

So I built the unicooler with a 12 x 12 air duct connected to a 12" HVAC collar which seems to be pulling a good deal of air in/out. I cant test the cooling effect much as I live in a higher humidity area. However it turns out the ports on the shiftpod are 6". Not sure where I got 12" but I'll have to get a reducer and hope that the air flow is sufficient.

One question I had, the endless breeze I have is pulling on low 30W, second level up is 36W, last level is 40W. Strangely the #1 setting is 36W, #2 is 30W, #3 is 40W. Is this normal or do I have a defective unit? I havent rewired anything, just pulling off the cigarette lighter connection into my battery. I thought the amp range was between 1.2 and 2.5? This is 2.5 - 3.4 which is a good deal more than I was planning for. BTW this is without the pad in the unicooler so there is no resistance other than the air duct.

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Popeye
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Re: cooling your tent or van

Post by Popeye » Tue Aug 13, 2019 11:18 am

For fans and pumps the more resistance you have the lower the amp draw. Counterintuitive but the amp draw is a measure of the work done. Close off the fan/pump output and very little work is being done. The fan/pump will get hotter because there is less or no flow to cool it off.
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Joeln
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Re: cooling your tent or van

Post by Joeln » Tue Aug 13, 2019 11:26 am

Waiting for other electronic geeks to chime in here, (especially ones who know brushless and fancier-drive DC motors). And leaving aside the confusion generated by your choice of the word resistance which can have opposite meanings depending on whether you are talking about the motor coils or the load its pushing.
In general my understanding of DC motors goes as follows:

"Stall current is the maximum current drawn, when the motor is applying its maximum torque, either because it is being prevented from moving entirely or because it can no longer accelerate given the load it is under.

Free current is the minimum current drawn when the motor is rotating freely at maximum speed, under no load other than friction and back-emf forces in the motor itself."
Popeye wrote:
Tue Aug 13, 2019 11:18 am
For fans and pumps the more resistance you have the lower the amp draw. Counterintuitive but the amp draw is a measure of the work done. Close off the fan/pump output and very little work is being done. The fan/pump will get hotter because there is less or no flow to cool it off.
Collapse first and avoid the rush

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Token
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Re: cooling your tent or van

Post by Token » Tue Aug 13, 2019 2:11 pm

Popeye wrote:
Tue Aug 13, 2019 11:18 am
For fans and pumps the more resistance you have the lower the amp draw. Counterintuitive but the amp draw is a measure of the work done. Close off the fan/pump output and very little work is being done. The fan/pump will get hotter because there is less or no flow to cool it off.
Hmmm ... gonna say negative to that.

There is “work done”, then there is “productive work done”.

The fan is drawing current and power regardless of the perceived benefit.

Stick a chopstick into that fan ... it will draw max amps and literally do nothing. But in effect, it IS doing maximum work pushing against that chopstick and trying to break it.

The lower the obstructions and lower the pressure drop in the path of the airflow, the higher the efficiency and overall perceived work done.

You getting confused on productive work vs parasitic losses.

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Popeye
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Re: cooling your tent or van

Post by Popeye » Tue Aug 13, 2019 4:49 pm

I should have said resistance to flow of water or air. The motor will still move at whatever rpm it is designed to move at. But with no work being done, other than the basic work to turn the motor/rotor/fanblade current flow will be at minimum. As you open a valve to permit flow or take the paper off the fan guard more work will be done.
Check it yourself, hook a pump to a valve and take ammeter readings. as you open the valve current increases as more work is done.
You can tell when a pump impeller is worn or an air handler filter is clogged by watching current. If current drops, you have a problem and you should change the impeller or the filter.
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Popeye
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Re: cooling your tent or van

Post by Popeye » Tue Aug 13, 2019 4:51 pm

Or just take an amp reading then remove the fan belt driving your pump or fan.
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Token
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Re: cooling your tent or van

Post by Token » Tue Aug 13, 2019 8:19 pm

I see where you’re goin there.

Focusing on the tree and not the forest.

Yes, you can isolate a component like a pump and derive no-load vs load diagram, and under some circumstances it can show less current with a denser fluid in the system. Rare but sure.

However it is not a truism for all circumstances.

DC motors tend to draw more current at low RPM than at high and most have specs that show that relationship.

When operating in their specified range, current will increase at a DC motor with load and lower RPM.

If what you are saying we’re universally true, my electric car would drive further on a charge the more I gun the pedal ... and that don’t happen.

ses2sus
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Re: cooling your tent or van

Post by ses2sus » Wed Aug 14, 2019 12:02 am

My group has now given up on the comfort of a cool van.... but our plan:

please tell me if we're stupid

dollar store reflectors on all the windows
carpet on the floor of the van
foam mattress
air cooling unit (desk size) with mister faced at a 16 inch fan

my friends scared we're gonna suffocate (CO poisoning)....

any tips? we wanted to bring an AC but too poor for a generator

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Canoe
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Re: cooling your tent or van

Post by Canoe » Wed Aug 14, 2019 8:47 am

ses2sus wrote:
Wed Aug 14, 2019 12:02 am
My group has now given up on the comfort of a cool van.... but our plan:
> dollar store reflectors on all the windows
Yes. Use red Stucco Tape; low/no residue. Works much better if they're on the outside. Cut into smaller pieces so they're held well by the tape. But will they take the wind abuse.
Cut sheets of Reflectix to fit glass, can take the abuse on the outside, has some insulation too.
If you have enough reflective material, do the SE sides and the roof.
Point van at the SE, so the engine area is taking the early morning sun.

> carpet on the floor of the van, foam mattress
sure
> my friends scared we're gonna suffocate (CO poisoning)....
How many people.
No smoking (CO). There should be enough air leaks to be fine. Crack a window; get a furnace filter to tape in place to keep dust out. Close when you're not in the van.

> air cooling unit (desk size) with mister faced at a 16 inch fan please tell me if we're stupid
This will provide some evap chilling until you've turned the hot dry air inside the van into cool humid air, then it will no longer cool (can't evaporate and produce chilling). The air will heat up until you have hot humid air. Open the door, let the hot humid air be replaced by hot dry dusty air, then you can spray again. People do the same thing, only without the fan and with a spray bottle. Make sure you use potable water.

> My group has now given up on the comfort of a cool van...
What's the cost of that mister and the fan? What power will they use? Do they need VAC, so you'll be buying and running an inverter too? You're planning on starting your car to recharge it's battery? And you have to keep dumping the hot humid air and taking in hot dusty air.

Or build a bucket-cooler to get chilled dust-free fresh air. Solves cooling and fresh air concern.
Don't substitute pads or fan and expect it to work well, or even work.
Bucket on ground (or on something to let it sit higher so the fan isn't working as hard) on the north or NE side of van. Run the vent straight up to one of the windows, opened enough for the duct plus another inch or two. Cut a piece of thin plywood or foam-board to fit the window and taped in place (stucco tape), with a matching hole for the vent for the chilled incoming air. Stick the duct in the hole, tape to seal. Now you need an exhaust, so the incoming chilled air can get in by it pushing out the air already in the van. There are some air leaks in the interior already, but crack a window enough to be getting good air-flow from the bucket-cooler. Make sure you close that cracked window when you shut the cooler off when you head out to explore BRC.
Using the van battery to power chilling will deplete it and abuse it. You need a deep cycle battery. Best deal is usually costco. Search this thread for the workable fans, pumps and battery capacity.
Video games are giving kids unrealistic expectations on how many swords they can carry.
.
... but don't harm the red dragon that frequents the area from time to time. He and I have an agreement.

ses2sus
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Re: cooling your tent or van

Post by ses2sus » Thu Aug 15, 2019 4:38 pm

Canoe wrote:
Wed Aug 14, 2019 8:47 am
ses2sus wrote:
Wed Aug 14, 2019 12:02 am
My group has now given up on the comfort of a cool van.... but our plan:
> dollar store reflectors on all the windows
Yes. Use red Stucco Tape; low/no residue. Works much better if they're on the outside. Cut into smaller pieces so they're held well by the tape. But will they take the wind abuse.
Cut sheets of Reflectix to fit glass, can take the abuse on the outside, has some insulation too.
If you have enough reflective material, do the SE sides and the roof.
Point van at the SE, so the engine area is taking the early morning sun.

THANK YOU FOR THIS. I think budget wise we ruled out aluminet/reflection material for the tops of the vans. We were gonna use gorilla tape/left over hexayurt tape for anything we needed tape on the van. Will look into the Stucco Tape material difference.

> carpet on the floor of the van, foam mattress
sure
> my friends scared we're gonna suffocate (CO poisoning)....
How many people.

We're 2 people in each van


No smoking (CO). There should be enough air leaks to be fine. Crack a window; get a furnace filter to tape in place to keep dust out. Close when you're not in the van.

> air cooling unit (desk size) with mister faced at a 16 inch fan please tell me if we're stupid
This will provide some evap chilling until you've turned the hot dry air inside the van into cool humid air, then it will no longer cool (can't evaporate and produce chilling). The air will heat up until you have hot humid air. Open the door, let the hot humid air be replaced by hot dry dusty air, then you can spray again. People do the same thing, only without the fan and with a spray bottle. Make sure you use potable water.

> My group has now given up on the comfort of a cool van...
What's the cost of that mister and the fan? What power will they use? Do they need VAC, so you'll be buying and running an inverter too? You're planning on starting your car to recharge it's battery? And you have to keep dumping the hot humid air and taking in hot dusty air.

We're borrowing the fan and mister. Our camp has electricity (BR Boutique) so we'll use that to recharge our fans. I'm starting to understand the heat build up a bit more from your response

Or build a bucket-cooler to get chilled dust-free fresh air. Solves cooling and fresh air concern.
Don't substitute pads or fan and expect it to work well, or even work.
Bucket on ground (or on something to let it sit higher so the fan isn't working as hard) on the north or NE side of van. Run the vent straight up to one of the windows, opened enough for the duct plus another inch or two. Cut a piece of thin plywood or foam-board to fit the window and taped in place (stucco tape), with a matching hole for the vent for the chilled incoming air. Stick the duct in the hole, tape to seal. Now you need an exhaust, so the incoming chilled air can get in by it pushing out the air already in the van. There are some air leaks in the interior already, but crack a window enough to be getting good air-flow from the bucket-cooler. Make sure you close that cracked window when you shut the cooler off when you head out to explore BRC.
Using the van battery to power chilling will deplete it and abuse it. You need a deep cycle battery. Best deal is usually costco. Search this thread for the workable fans, pumps and battery capacity.
Thanks for all this information, we've been looking at swamp coolers. Just don't know if we have the budget for it. Will look again. Thank you!

ses2sus
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Re: cooling your tent or van

Post by ses2sus » Thu Aug 15, 2019 4:40 pm

Canoe wrote:
Wed Aug 14, 2019 8:47 am
ses2sus wrote:
Wed Aug 14, 2019 12:02 am
My group has now given up on the comfort of a cool van.... but our plan:
Forgot to mention, we're in uhaul cargo van. There's a metal wall between where we sleep & the front seat. Front seat has the only two windows in the van that open. I think the concern with the swamp cooler system is we don't have a window to shove the pipe/exhaust piece out of.

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Canoe
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Re: cooling your tent or van

Post by Canoe » Thu Aug 15, 2019 7:51 pm

Video games are giving kids unrealistic expectations on how many swords they can carry.
.
... but don't harm the red dragon that frequents the area from time to time. He and I have an agreement.

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Re: cooling your tent or van

Post by sunrise_giraffe » Mon Aug 19, 2019 11:29 pm

Thoughts/questions for next year’s burn.

I have a couple friends in my camp who I recently learned are bringing Shiftpod Mini’s. I have a feeling they’re going to get real hot inside at the burn this year and afterwards are going to ask me about building a swamp cooler since I’ve walked a bunch of folks in my camp through how to build them in the past. This is the kind of thing I love helping people with.

My understanding is Shiftpod Mini’s are around 168 ft^3, have a 3.5” diameter opening that can be cinched closed, and have at least a couple windows that can be zipped open. What are people’s thoughts on building a bucket cooler with a 3” duct hooked up to the Delta QFR0812DE-F00 fan:
- 80mm x 80mm x 38mm
- 12v
- 1.15a
- 105.21 cfm
- 1.34 inchH2O

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Canoe
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Re: cooling your tent or van

Post by Canoe » Tue Aug 20, 2019 12:23 am

A single 3.5" "Power Port Opening" can be where the output from the bucket cooler goes into the pod.
Crack a window to an appropriate size (6" duct) for the required exhaust airflow when running the bucket cooler.
The airflow it gets will be what it can get through that Power Port Opening.

The static pressure of that fan is way too low. Usual fan is 17 inchH2O. And that's before considering the CFM is going to drop and the pressure go up as it is restricted down to the 3.5" opening. I don't know how to calculate what it would be. I don't even know what it is for a bucket cooler.

Feeding that pod may need more than the usual static pressure. As it gets cut down from 6" to 3.5" round or 3.5" x ____, there will be restrictions and an increase in velocity/noise. Once you get better info on the opening, dimensions and photo, so we can know the actual area of the opening, then someone can do the math. And once we know the pressure that would build up due to the restriction, you can calculate the CFM it would generate. And that has to be calculated for a ~7,000 density altitude (hot day thins air), a 78.19 kPa atmosphere.

You are better using six inch duct from the cooler to the pod, as 6" for six feet loses 2.38 % at 170 CFM for 167 CFM, and 3.5" loses 21% at 170 CFM for 134 CFM. 3.5" duct will pass 41 CFM at the same resistance loss as 6".

They can cut down on the heat-gain by shading it.
Setup to the west or NW of the tallest shade producing thing they can find, so it's shading them from the early morning sun.
Look at shade solutions used for 6'x6'x3.3' tents.
Like shiny hexayurts, others may not like them being too close as they will be reflecting sun/heat at those around them.

Worse case, as the volume is small, and it's got radiant barrier and some insulation (its heat gain will be smaller than if it didn't have those), so running a bucket cooler is likely to be worthwhile, even with that constriction.

On playa, get them to pay attention to morning shade or not, and when in the morning it starts to get warm vs. hot, and when/if it becomes too hot to stay inside of. Then you'll know a ballpark on its heat gain.
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.
... but don't harm the red dragon that frequents the area from time to time. He and I have an agreement.

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Re: cooling your tent or van

Post by FIGJAM » Tue Aug 20, 2019 6:44 am

I would build the bucket exactly as designed and add a 4" to 3" reducer to the 4" septic pipe.

That will fit perfectly in that 3.5" hole, and you'll have close to 190cfm coming into the tent.

Vent with a window opposite the cooler and you're all good.

Complete air exchange every minute!!! 8)
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Canoe
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Re: cooling your tent or van

Post by Canoe » Tue Aug 20, 2019 10:52 am

Canoe wrote:
Tue Aug 20, 2019 12:23 am
...
You are better using six inch duct from the cooler to the pod, as 6" for six feet loses 2.38 % at 170 CFM for 167 CFM, and 3.5" loses 21% at 170 CFM for 134 CFM. 3.5" duct will pass 41 CFM at the same resistance loss as 6". ...
My Bad. I misread the loss in inH2O as a % loss.
I use 5" dryer duct, so 190 for six feet drops to 190.52 at 23.2 ft/sec. With 4", it drops to 188.52 at 36.2 ft/sec. Negligable drop.
Then to get through 3" nominal, calculation is showing 64 ft/sec.
Video games are giving kids unrealistic expectations on how many swords they can carry.
.
... but don't harm the red dragon that frequents the area from time to time. He and I have an agreement.

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Token
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Re: cooling your tent or van

Post by Token » Tue Aug 20, 2019 1:12 pm

Or upgrade to the 5200RPM Delta fan instead of the 4000RPM.

Bumps you to 240CFM but at double the current/power draw.

Those suckers are LOUD!

Had 6 in a piece of HP gear once and at boot they would spin up to max before the thermal circuit kicked in. Like a jet engine in the data center.

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Re: cooling your tent or van

Post by sunrise_giraffe » Tue Aug 20, 2019 1:19 pm

Canoe wrote:
Tue Aug 20, 2019 12:23 am
The static pressure of that fan is way too low. Usual fan is 17 inchH2O.
The spec sheet I’m looking at for the Delta AFB1212SHE-CF00 shows an air pressure of 0.694 IN H2O. That’s 17.64 mm H2O. The 80mm fan I was looking at has higher static pressure. Or maybe I’m misunderstanding something, this is pretty far afield from my area of expertise.

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Re: cooling your tent or van

Post by Canoe » Tue Aug 20, 2019 2:42 pm

sunrise_giraffe wrote:
Tue Aug 20, 2019 1:19 pm
Canoe wrote:
Tue Aug 20, 2019 12:23 am
The static pressure of that fan is way too low. Usual fan is 17 inchH2O.
The spec sheet I’m looking at for the Delta AFB1212SHE-CF00 shows an air pressure of 0.694 IN H2O. That’s 17.64 mm H2O. The 80mm fan I was looking at has higher static pressure. Or maybe I’m misunderstanding something, this is pretty far afield from my area of expertise.
No, that's my bad again. Miss read, miss used and miss typed.
It's 17 mmH2O. Or more precisely, as you said, 17.64 mmH2O.
I misread because we're so used to people substituting low static pressure fans, I saw a low number vs. the 17.
It didn't make sense to me that it was simply the resistance of 3.5" for the length through the wall. With the low CFM nagging me that maybe it was, but I couldn't calculate to prove it. In trying to find the throughput through 3.5" at playa altitude on a hot day, and I was back and forth from various tables and converting from one unit to another to match formulas to get pressures on each side of the 3.5" for the resulting CFM.
And with you catching the mmH20 vs. inH2O, I just went and checked my spreadsheet. I was calculating the inH20 drop but taking it off mmH20 too...
That's what I get for tackling this after staying up to 3 am to do some last minute requests for a camp.

Taking the airflow from that 4" duct down to 3" to go through a 2" long fitting is negligible. Using the correct units (thank you), I'm getting -3 CFM.
Video games are giving kids unrealistic expectations on how many swords they can carry.
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... but don't harm the red dragon that frequents the area from time to time. He and I have an agreement.

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