Evap Coolers?

For those that have deleted their rooftop AC, has anyone opted for a small and relatively inexpensive 12v portable evap cooler? Any recommendations?

Thanks.

OneManVan was tinkering with the idea:

https://sprinter-source.com/forum/showpost.php?p=248043&postcount=7

Full thread:

https://sprinter-source.com/forum/showthread.php?t=27332&highlight=Cooler

Other threads on non-Westies:

https://sprinter-source.com/forum/showthread.php?t=17356&highlight=Evaporative+cooler

https://sprinter-source.com/forum/showthread.php?t=16566&highlight=Evaporative+cooler

Greetings.
As you may or may not know, evaporative coolers a.k.a. swamp coolers, work optimally to a maximum of 20% humidity. Beyond that, their affective feeling of cooling diminishes, in fact, it can make it feel warmer. Here in the bald arse Mojave Desert they work great, except during the monsoon season.

Operation:
A submersible pump draws water out of the 10 liter dromedary bag and sprays water over the top of the cellulose cooling pad. The water drains out the bottom of the cooler back into the dromedary bag. Water consumption depends on ambient temperature & humidity - at most about 1 gallon per hour. Energy consumption is about 45 watts. Efficiency about 87% based on psychometric charts: https://www.engineeringtoolbox.com/evaporative-cooling-d_698.html

Nylon strap supports the weight of the water bag and the cooler.
Don't want to put too much load on the electric window mechanism.

The cab area is often the hottest place in the van - especially after driving all day - heat is radiated up through floor from engine/transmission - plus solar gain from front area glass. So the window mount location is very effective. Oftentimes I run it only in fan mode - ie: no water flow. Need to leave upper berth side vents and bathroom vent partially open. Can go off during the day hiking and know the van is going to stay cool and secure

Endless breeze fan:

http://www.amazon.com/gp/product/B0000AY2Z6/ref=oh_details_o08_s00_i03?ie=UTF8&psc=1


Pump timer control module ( programmed to 2 minutes on and 3 minutes off )

http://timers.shop/Multi-Functional-5V-20V-Time-Delay-Relay-Timer-5-amp_p_12.html

Most of the raw materials are aluminum angle and FRP - dry weight is about 5 pounds.
One layer of fiberglass cloth makes the bottom water tight.
1/2" copper pipe for the sprayer.

Smallest chunk of cellulose cooling pad I could find was 12 X 6 X 36.
I cut it into three equal pieces on the band saw at the shop in the park.
Leaves me with two spare pads...

The submersible pump - little blue thing - hangs inside the water bag.
It's the same model pump as the one in the Westy water tank - IE: comet.
It's power cord and water supply line run up through the discharge tube.
12 volt power is via a cigarette plug that goes to outlet on the dash.

Have to get the voltage divider resistor sized right for proper flow rate.
It's the gold oblong thing in the middle of the fan with green and black clip leads on it.
Testing water flow rate - looking for 1/2 gal/min.

Cleaver, excellent craftsmanship!!!

Testing on a hot day: 110 outside 82 inside

Onemanvan, thanks for that detailed write up and photos. I've got to do something to help keep the dogs cooler. Cheers

When not in use I store it behind the bench seat along with my dirty cloths hamper

What about bacteria & fungi growth on the media? Do you use peroxide, silver or other bactericide? Seems like the water bag should be white, not black like a solar shower.

MrTomacco said:

What about bacteria & fungi growth on the media? Do you use peroxide, silver or other bactericide? Seems like the water bag should be white, not black like a solar shower.

Click to expand...

After five years of use no problem with bacteria/fungi. Unlike conventional 'swamp coolers' this one gets emptied and dried out on a very frequent basis.

Agreed - a white water bag would be preferable. The 10 liter MSR dromedary bag satisfied all the 'form, fit, function' requirements except for color - which is not an option...

Wrap the bag with Reflectix?

I can see where one might look at the black bag and think 'solar shower'. Indeed - if you laid that bag out flat in full sun the water would heat up over the course of several hours.

However...

The bag hangs under the cooler so it's shaded for much of the day.

The only time it's going act as a solar collector is when:
1) The passenger side of the van is facing west
2) It's after 2pm?
3) There are no shade trees on the west side

On average the water in the bag gets recycled every few minutes - 1/2 gallon per minute flow rate. From my experience the water in the bag always feels cool to the touch. The few degrees of solar heat gain that might occur isn't going to affect the evaporation rate of the moisture in the cellulose media - which is what creates the cooling effect.

White or reflective would be better than black - however - IMHO the difference in performance would be quite small.

So outrageously inventive and beyond my skill set that's it makes me laugh...where's the kudos button around this establishment...?