Micro swamp cooler
 

My 1982 GMC standard cab has no AC. I got the idea to build a tiny evaporative cooler that draws its supply air from the passenger side vent, which gets its air from the grill slots on the cowling in front of the windshield.

The hope is to reduce the heat build-up while the truck is parked in town on a hot day.

I made a plywood adapter plate that is glued to the vent valve on the passenger side. I might have wanted the outside air supply to come from the drivers side, but the emergency brake, hood release, and clutch pedal would made it difficult.

A 12 volt computer fan came from an old power supply, measures 3 inches.
The evaporator pad was cut from a Honeywell humidifier pad on the table saw to match the fan housing.

The water pump was purchased on eBay for about $6, it is meant for a tabletop fountain display. At 12 volts, it screams and pumps way too much water. Two ten ohm, ten watt resistors (Radio Shack) in series made the flow reasonable. I may add an aquarium valve to the line later for fine tuning. I made photos as I built it in case I want to draw up plans to sell.

The fan draws .3 amps, the pump .4. This is low enough the the cooler can run continuously while parked without danger of running the battery down. This means I no longer have to get into a red hot car after an hour or so of shopping. The AC (if I had one) would not have to pump its little guts out, burning a lot of fuel in the process.

These are the figures for the first test (today)
14:15 start, temp 92 outside.

time......cab......outside
15:16..... 92........ 95
16:15..... 97........ 95
17:15.....113........98 (ran out of water) The final version will have a water gauge.
18:30......87.........96
19:30......87.........96
20:00......67.........94 This was driving in the dark at 45 MPH Comfy!
The faster you drive, the better it works.

Other uses for the cooler would be pull it out of the truck and cool your camp tent, or you could even stick the hose in your sleeping bag. (I will have to try that.) It is easy to remove by simply unplugging the cigarette light plug, and slipping the supply hose off,

Tomorrow I will make more tests in the shade with the windows
cracked just enough to get my finger out.

I realized a few changes I should make on the next version....
1. The final version may have a water gauge, perhaps a cork with a Popsicle stick.
2. Wider sump (plastic storage bin with lid) to prevent tipping, increasing water capacity.
3. Perhaps two 3 inch output hoses to direct air to the driver and passenger.
4. I will look into the possibility of a unit that mounts under the dash to give more legroom.

Re: Micro swamp cooler
 

6-22-11
Start-14:00 ambient 94, cab in sun 127, breezy, gust to 20 MPH
Both windows cracked ~1 inch, in shade under a tree
time cab outside
15:00 87 100
16:00 90 102 Low on water, partly in sun. Moved PU
17:00 91 97

I did not expect the result to worse in the shade and the widows cracked. My guess is hot air was coming in the crack in the windows faster than it could keep up with. It used about twice as much water today.

Re: Micro swamp cooler
 

Great idea and real results. You must live in an area with really low humidity.

Re: Micro swamp cooler
 

I would drill a hole in the plastic cap for a 2 liter bottle, and install a length of aquarium tubing. Place the end in the water tray, and invert the bottle. When the water runs low, air will enter the bottle, and release water until the hose end is under water again and no more air can enter the bottle. This way you have an automatic filling water tray.

Re: Micro swamp cooler
 

Humidity yesterday was 14%, 20% today. Our "monsoon season" is supposed to start soon.
I am hoping to get some good humid day readings.

Re: Micro swamp cooler
 

I had planned on doing something like that. Next version should give me a little more room to work.

Re: Micro swamp cooler
 

I don't think I've ever experienced air that dry, here in New England.

Re: Micro swamp cooler
 

Nope, air that dry does not exist on the east coast. Even now at 7:45 AM its 67% humidity, and its only going to get hotter and more humid as the day goes on.

Re: Micro swamp cooler
 

This is the temp and dew point for the 21st. recorded at a private station about 8 miles from me.

Re: Micro swamp cooler
 

This experiment isn't for everyone. If homes have evaporative cooling in your area it may work for you.
Here is a page that might give you an idea of what to expect:https://www.littlegreenhouse.com/acce...t-cooler.shtml