I've discovered a unique way to keep my van considerably COOLER.

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CosmickGold

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I had the idea that the air near the ground under the van should be cooler than the air coming in my Fan-Tastic roof fan. So I drilled a hole in the floor to suck the air up, and reversed the direction of my ceiling fan to blow the air out at the top instead of bringing it in.

I am truly astonished by how much difference that has made! I'm so much more comfortable inside my van now, even when it's near 100F outside.

Drilling a large hole in the floor and reversing the ceiling fan to blow air out, might be enough for your rig, but I got fancier. Here is my so cool (pun intended) layout:

1. I cut a hole through the floor the right size to place the end of a 4" bilge fan into it.

2. I bought this 36"X84" role of Standard Window Screen (originally to keep bugs from coming through my windows, but it is great for this purpose too). Soft and flexible, it was easy to cut with scissors to the right size to cover the hole in the floor plus a couple of inches more on each side since I will press it down into the floor with the fan.
Image 8.jpg

3. On top of this goes my 12V 4" in-Line Marine Bilge Air Blower which I pressed snuggly down into the drilled hole, securing the window screen as well.
Image 6.jpg

4. The fan inside the Bilge Air Blower is really noisy. I used this vehicle door/floor/wall surface sound deadener (which quiets the sound down quite a lot). The backside of the material is very sticky after you peal off the protective paper, so it was easy to coat the entire outside of the bilge fan with the stuff. This also helped make the bilge fan fit snuggly into the hole.
Image 9.jpg

5. The wires from the fan go through this Waterproof Junction Box in which I installed this 15A DPDT 3-position switch. The switch is wired so that if flipped up, the fan sucks the air up, and if switched down, the fan blows the air down and out of the van. Of course, the middle position is off. And be sure to put a fuse on it! (The fan seems to pull about 6 amps, but the start current nears 15 amps, so the fuse needs to be for 15 Amps.) And of course, all your electrical circuits should be fused for safety. (Like Smokey the Bear used to say, "Only YOU can prevent van fires.")
Image 4.jpg Image 3.jpg

On top of the bilge fan goes the six-inch diameter duct, which I lined with this one-inch acoustic foam. The foam reduces the 6" air path inside the duct back to the 4" diameter of the bilge fan (hence, the reason for using a six-inch diameter duct). I cut the duct to a length of only two feet so it would stand straight up under my desk while active on top of the bilge fan. That deadens the noise coming up from the bilge fan really well. All I hear coming out of the end of the duct is the rush of air.
Image 1.jpg Image 2.jpg

To my surprise, I seldom need to run the bilge fan because the ceiling fan pulling air up through the bilge fan and duct does the whole job quite well.

CAUTION: Having both the engine exhaust blowing out carbon monoxide under your rig, and this hole in the floor drawing in air from under your rig can be deadly!. Never do both at the same time! It is best to keep the hole in the floor covered while the engine is turned on. And to start with, cut the hole in your floor well forward of the exhaust, and on the opposite side from the exhaust. Be safe, be healthy, and stay alive!
 
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gizmotron

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I have four of them, not your exact type, but four small exhaust fans with individual switches for each fan. Some are ducted to take out warm air from isolated parts of the van's living space. If I need or want more I will add more. When I'm all locked up and in a store shopping or something like that I have them running to keep the van cooler inside. Sure, the typical roof vent / fan takes out a lot of hot air. But my system puts air out the back floor or the side. I installed a real RV style screen door / opening and closing screened window in the space between the cargo doors and the false inner wall where that door goes. That's my insect proof inbound ventilation.

I really like your thinking on this idea of moving the hot air out.
 

RoamerRV428

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very cool for you...get it, cool but cool hack for what you need :)

be sure to put in a filter of some type cause 'off ground' air can contain more rat feces or animal issues, allergy draw issues or xyz/abc so I would put in a small filter for that draw only that it would be super simple to add in context for a more 'secure' issue you are tackling. well that would be my thinking LOL but do you of course :)
 

CosmickGold

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very cool for you...get it, cool but cool hack for what you need :)

be sure to put in a filter of some type cause 'off ground' air can contain more rat feces or animal issues, allergy draw issues or xyz/abc so I would put in a small filter for that draw only that it would be super simple to add in context for a more 'secure' issue you are tackling. well that would be my thinking LOL but do you of course :)
Good thought. I certainly don't want to be breathing rat feces, etc. But I think I'm good with that air intake more than two feet above the ground, and the air sucked in through the fine mesh of window screen. If you can post the URL to the kind of filter you speak of, I'll certainly have a look at it. But right now, I have no idea what that would be.
 

flaggit

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I have a Hessaire Swamp cooler that draws about 150 watts. I run that off my solar during the day and it really cools things off, but only in the desert or other low humidity conditions.
The spreadsheet below shows the temperature drop for a given humidity. For me, I stay in the 15-40 % humidity conditions with temps between 80º and 100º. Keeps me comfortable!



%Relative Humidity2%5%10%15%20%25%30%35%40%45%50%55%60%65%70%75%80%
75º5455575859616263646566676869707172
80º5758606263647767686971727374767677
85º61626365676870717273747576777981
90º64656769707274767778798182838486
95º67687072747678798182848587
100º6971737678808283858788
105º727477798184868889
110º7577808385879092
115º78808386899194
120º818386909395
125º8386909396
 

bullfrog

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Silver foil reflex on a roof rack and plenty of air flow under the solar panel can make a difference as well. My neighbor last year used a mister on her roof and lowered the inside temps by about 10 degrees but ruined her paint with calcium deposits! Using a mister if you have a water source under an awning a few feet from the door works pretty well also in dry desert climates.
 

CosmickGold

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. . . . plenty of air flow under the solar panel can make a difference as well. . . .
Yeah! I mounted my four solar panels three inches above the roof on vertical posts through the roof bolted to the ribs below. I did this because I read the hotter solar panels are, the less electricity they make. But two more benefits are that they make a perfect sunshade, and they reduce the sound of rain to a slight pitter-patter very pleasant to hear.
 

eDJ_

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Just as an aside, I made screens for my front windows with those vinyl rain gutter shields from Lowes. They come in white and brown and are about 6 inches wide. Just take some paper and trace the inside of the rolled up window to make a pattern that is 6 inches wide. It will take two pieces of these shields to do the right and left. The screen is glued to the back side of the perfed vinyl and these are handy items. I think we had a thread on this some while back.

Rain_Gutter_Guard_WS.jpg
 
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CosmickGold

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. . . . I made screens for my front windows with those vinyl rain gutter shields from Lowes. . . .

That's a great idea! Lowes is nearby, so I'm going to do the same as you with my front windows. (I built a wall between cab and living area.)

Years ago, I foolishly bought one of these little 10"X10" "air conditioners" (really an evaporative cooler) and found it to be a waste of money. They come in several different designs but all run on USB power, which I've since learned does not provide enough power for any motor (fan, water pump, etc.). Anything with a motor needs to run on 12 volts to really do its job.
Image 12.jpg

Now, if too hot, I cool myself with this combination. The 12-volt fan is surprisingly strong, blowing the air right where I point it (which is on me). And the sprayer puts its mist directly on me, so I'm what gets cooled. Unlike the "air conditioner" above, this combination really works, as in "Aaaaaa!"
Image 13d.jpg
 

Marcos989A

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Power-assisted convection with the fan-mounted exterior to the interior is the answer. The inside uppermost area needs only an exit air path, an exit fan is an option but creates sound and uses energy. Simply pumping in cooler air will cause the warmer air to exit given a pathway. Options are always the best.
 

bebewanna

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Here is my cooling off solution...

2 windows finished and 2 to go...
Simple... Tape out stretched a $1 mylar blanket (I got 20 for $20). Spray with loctite cement (can $6) lay cardboard over mylar.. Aluminum tape the edges so coming magnets can more easily be removed...
Sliding door fits both sides... Sun only hits 1 side at a time
Rear wing window is mylar both sides so just needs moved.
Wind has howled last few days, no problem
Need to finish door and rear window.
Front window is another story.. The Cats safety zone is on the roof so I just replace the mylar after they shred it going up lol


It cools the car considerably... For cheap

I have a full coverage aluminet cover but the wind has been howling and I don't want it destroyed..

I have flexible solar panels on the roof and yes they get hot, one the end is warping up between the grommets...
 

CosmickGold

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Here is my cooling off solution...

2 windows finished and 2 to go...
Simple... Tape out stretched a $1 mylar blanket (I got 20 for $20). Spray with loctite cement (can $6) lay cardboard over mylar.. Aluminum tape the edges so coming magnets can more easily be removed...
. . . .
I bet that makes a major difference in keeping the heat out. You've "got a plan", as they say.

Someone on here said they tinted their windows to keep the heat out. <????> I don't understand that, because my windows came factory tinted quite dark; and that dark makes the glass turn very hot when the sun is shining directly on it, instead of keeping the heat out. Do you know what type of coating she was talking about that keeps heat out?

My way of stopping window heat has been to (1) cut 1/2-inch sheets of blue foam Wall insulation to exactly fit my window glass. (2) Stretch a bungee cord over the window from center-top to center-bottom. (3) Put a 2" square block of wood behind the bungee chord right in the center to hold the insulation tight against the hot glass.

That's a strange solution, but it's what I've got that works. Magnets would not work for me because NOTHING anywhere near the windows is magnetic. But I like having my solution on the inside so I don't have to be concerned about what's happening on the outside, whether city or country, day or night, storm or shine.

But I suspect that if the amount of heat blocking from your technique were compared with mine, you'd win the contest!
 

bebewanna

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I bet that makes a major difference in keeping the heat out. You've "got a plan", as they say.

Someone on here said they tinted their windows to keep the heat out. <????> I don't understand that, because my windows came factory tinted quite dark; and that dark makes the glass turn very hot when the sun is shining directly on it, instead of keeping the heat out. Do you know what type of coating she was talking about that keeps heat out?

My way of stopping window heat has been to (1) cut 1/2-inch sheets of blue foam Wall insulation to exactly fit my window glass. (2) Stretch a bungee cord over the window from center-top to center-bottom. (3) Put a 2" square block of wood behind the bungee chord right in the center to hold the insulation tight against the hot glass.

That's a strange solution, but it's what I've got that works. Magnets would not work for me because NOTHING anywhere near the windows is magnetic. But I like having my solution on the inside so I don't have to be concerned about what's happening on the outside, whether city or country, day or night, storm or shine.

But I suspect that if the amount of heat blocking from your technique were compared with mine, you'd win the contest!
The glass underneath in full sun is cool...My Grand Caravan is a Sport, super dark back windows but the glass is still blazing hot. I thought about putting darker film but
Without the reflective stuff... Still glass is hot.
I figured it out because this van has a tremendous windshield and at first it was baking me. I have some mylar that has black backing and it kept the windshield cool all last summer even on 120f days we had. The temps here are OK but the sun is really brutal...
I am concerned about rain but seems here that's rare... Clouds just blow over.
 

CosmickGold

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I googled your word "mylar" and learned that "Mylar reflective insulation is comprised of polyester and aluminum, resulting in a silver-colored radiant barrier that reflects radiant heat." So that's what she must have been talking about. Her windows must look silver from the outside, reflecting the heat like a mirror before the heat can reach the glass. My windows, on the other hand, look black from the outside, absorbing every bit of heat they can persuade to come their direction!
 

Happy Camper

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This is a thread from the way back machine that applies to what you're trying to accomplish. I hope this helps.

Btw to I had to use some of my special necromancy skills to wake this one up.

The entire thread is worth reading. But read Sternwakes novels/posts. He made an art form of cooling with small efficient fans.

 
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