Tales from a Ventilation Lunatic

[Roadtripp]

My head began to swell after doing a little reading about evaporative cooling science. Apparently there are direct and indirect systems. The simple direct system most of us know add moisture to the space but are efficient (when the supply air is relatively dry). The indirect systems do not add moisture to the space product air but are not as efficient as far as cooling. And there is a newer “dew point” indirect system that is almost as efficient as direct system but it’s a rather complex maze of perforated layers that I did not comprehend without further study. It sounds expensive. 
 I’m thinking of going with more fans like you and damp clothing. Maybe what you felt on your inner arms was “latent heat”?  I’m not sure.

[sternwake]

Been about as humid, and as hot as it gets when humid, round these parts lately.  Former hurricane Elida pumped a whole bunch of hot moist air up this way.

Lots of high clouds too, for not very impressive solar harvest. 

Yesterday morning, well what passes for morning with my night owl tendencies, my intake fans felt like they were pumping in superheated swamp air.  It was 89f inside around noon, and sticky humid.  Pretty miserable.  I wet the sarong laid it over my bare chest, aimed 92mm delta fan fan at it at medium high speed, and was still able to get the chills within a minute, despite the high humidity, which the news said was 85% RH.   Went from intolerably hot and miserable, to comfortable, quickly.

Late last night was also uncomfortably hot.  I had my top sheet and lightweight Mexican blanket levitating over my mattress, held aloft with the 3 intake fans at pretty low speed.  I decided to get under the levitating bedding.

Wow.  it was amazingly pleasant with a steady breeze blowing down body.  the slightest movement on the mattress and the body heat was instantly  excavated and pushed out the sheets by my feet. it was like every movement was the as nice as the cool side of the pillow.  I got Fiona under the blankets too and she was in heaven as well, nose nearly pressed upto Papst fan 4 paws in the air, snoring.
   

   


I actually got too cold and turned off the delta fans  blocked their faces with my curtain, and just ran the Papst at just enough rpm to keep sheet levitating over body.  Some 7 hours later I awoke and  got out from the levitating bedding and it was 94f in the van outside the levitating cocoon, but my IR gun shot at mattress where I had just been laying, under the levitating bedding was 84f.

I did have my other fan's going, but outside the covers was ridiculously hot and I dove back under for another hour.  When I did finally get out from under it was damp sarong time, and extra strong coffee with Ice added.


The ceiling Delta exhaust fan got removed and cleaned again, and the clear nail polish over the circuit board and Amazing goop protection as well.  no chance of rain so I removed the Mushroom vent above it.  Mini sky light, and better exhaust flow with it removed.

I have Ideas for a more obscure/ less restrictive mushroom portion, but that's way down the list.

[rvpopeye]

A read "fan dog"fer sure !

[sternwake]

I have black bungee cord stretching across the rear windows, they make it easy to place pillows up there in daytime for extra insulation against heat radiating inside.

But these Bungeees also make it easy to binder clip the bottom sheet and blankets up above head level, then the fans can more easily levitate the rest of the bedding.

It was not quite as hot last night and I only needed the papst fan at just above minimum speed, which is not really enough to fully levitate top sheet and mexican blanket. I took the binder clips and clipped it up above/ around the papst body and split the flow, 1/3rd to me 2/3rds to Fiona on the other side of the body pillow barrier and turned the Papst on just high enough to get it levitating over her and partially over me. It was just enough flow to keep me comfortable and my head was well outside the direct flow and Fiona was under the covers on the other side of the 'body pillow' snoring away paws to the sky under the barely levitating sheet.

Fiona about 4 Am each night, without fail, decides to get up, shake vigorously, jump off the bed and lie on floor at base of the bed. With this new levitating bedding, She managed to seemingly wrap the entire bedsheet around her and jumped while still entangled with the blankets and could not extricate herself. Her frustration was amusing, and I am glad I just washed my floor, as she wound up taking out her nearly water bowl some distance away when trying to rid herself of it. The wet spot on the sheets was of course right in the middle.

I made the bed, clamped the one side over the fans, turned on all three fans on just enough speed to levitate the now wet bedding , and climbed into the high pressure cocoon, and went back to bed.

Despite the airflow filtering slowly through through bedding, away from my body, where that wet spot was, seemed extra heat hungry. none of the wet bedding was touching my body but it seemed to suck more heat from my middle areas where it was wet, and felt ice cold to the touch. In about 15 minutes it was barely damp anymore, the extra cooling effect abated, and I went back to one fan only.

I think if I could not have levitated my waterbowled bedding, I would have had to broken out a new topsheet. Not a huge deal, but.....I didn't have to.

Even with RH at 80+ the evaporative cooling is working well, better than I expected, and also in ways not expected.

I am thinking with enough potential airflow, and some water to evaporate, one can get themselves out of the uncomfortably hot/overheated miserable zone.

But really, this is not South Carolina in August with 95f and 98% RH @11pm.

The quickest way still seems to be the wet lightweight cotton sarong with fan aimed at it in direct contact with maximum skin area, but the damp levitating bedding 10 inches over my body, was still a heat magnet.

Obviously once dried, the evaporative cooling effect is gone, but it has been enough to take the edge off and allow comfortable sleep thereafter.

All hail airflow!

[rvpopeye]

What a spoiled pup !
Lucky to have been adopted by you for sure !!!

The pics were killer ....skuh kuh kuh kuh kuh 


I use an evaporative cooling method here with my fantastic on exhaust..
But can't figure out how to get the levitating sheets with the roof vent fan though..
I just open a window and get in front of it with a spray bottle...

Or go stand by the ocean.  I'm guessing you know that trick !

Nice idea with the pillows

[Scott7022]

I like happy pups. You’re hot imagine having a fur coat and only your tongue to sweat with! Great dog Dad.


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[sternwake]

CAD

Cardboard Aided design

Mushroom vent restrictive.  Never quite liked its visuals on my roof either.

   


   

Nowhere near final design or intended symmetry.

   

Have epoxy and fiberglass to lay over something similar, paint same color as roof.

Can increase airflow from 120mm 190cfm Delta fan
Can improve. roof aerodynamics marginally, and make less obvious there is a vent up there.

Could just set cardboard on fire and return stainless steel mushroom and not waste my time.

[Scott7022]

Visually appealing is never a waste of time. Unless you’ve been waiting in the hallway for her, for forty minutes with her Mom being a bit to attentive. Lol.


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[B and C]

And her dad is at the kitchen table cleaning a weapon! LOL

[sternwake]

The redesigned cover has been on my mind for a while.

This Nicro 4" Marine vent, no longer offered, in place since July 2001, installed off center, grrrrr,  had a little sub 3v solar panel and would keep a C size Nicad battery charged. Enough to run overnight.  But pretty pitiful airflow overall.  Better than no roof vent for sure.

Within a few years the little enclosed brushed motor would click annoyingly, especially in colder weather. No switch to turn off.

One of my initial super quiet super low rpm/amp draw 120 mm fans got placed up there temporarily one day in 2008, and increased efficacy so much, that temporary became more refined and more powerful and less restrictive in many stages over the next 12 years.

I have all the materials and workspace to make a new  better more aero less obvious higher airflow cover offset, to account for initial installment error. I would be a fool  to not take advantage of the opportunity.  But I get lost in potential refinements. 7 potential steps ahead, things get blurry.

I get annoyed with the 4 inch aperture limitation, but I also ain't cutting a 14x14 hole up there either.

Ideally I'd like a hole to fit a 140mm computer fan without a  diameter reducing stepdown ring.

I'd love to engineer a  low profile similar roof vent, all around a 140mm or a Papst ~170mm fan.  

maybe its time to design and make a 140/ 170MM fiberglass  rainproof vent.

perhaps its time to stop thinking about it and cross other things off the list before adding more to it.



So many potential projects...
Such inefficient use of my time. 

How do people with actual  jobs and responsibilities ever get anything done?