Experimental micro swamp cooler device

[eggsalad]

You've seen the "5-Gallon bucket of ice" swamp coolers. They do have some issues, because some of the ice becomes water vapor and can condense inside the camper.

Fortunately, I live in a desert, so condensation really doesn't become an issue. As you'll see, this tiny chiller doesn't use the sort of ice that becomes water vapor, either.

Also, being as this device is really tiny, it can only work in a very tiny trailer. My trailer is <80 cu. ft. in volume. I don't anticipate a huge temperature drop nor a long cooling time. This is something I knocked together with stuff around the house and the shop, so it doesn't cost a penny to try. I like that.

I didn't take pictures along the way, but once you see the finished product, the steps will become obvious.

I started with an old Desktop PC power supply. I gutted out everything but the fan, and I flipped the fan around so it blew *inside* the case, not outside. I cut a hole in the top, and replaced it with a steel plate on some spring hinges I had lying around. Now on to the pictures so you can see...



Pretty simple so far, huh? Now what's the mystery chilling medium?



Yup! Lunch cooler packs! They might sweat a bit, but not like plain ol' ice would!

So there it is, pretty simple. It's a bit chilly outside to test it, but it will be warm soon enough and I'll post some results.

[RioWilson]

Cool idea...will be interested to see how it works!

[eamarquardt]

Not to spread "negative waves" but the cooling power of a couple of "blue ice" packs isn't gonna do a heck of a lot. Most folks are reporting good results with a 5,000BTU window shaker. Factoring in a duty cycle of maybe twenty percent that's about 1,000BTU/hour. Each pound of blue ice can absorb about 150BTU (or less).

So, if you have 3 pounds of ice in your device yer gonna get the cooling power of running 5,000BTU air conditioner for about 5 or 6 minutes. Then yer faced with the issue of refreezing your "ice" supply. How are you going to do that?

IMHO there just isn't viable solution to portable air conditioning (particularly in humid climates) other than a compressor driven system utilizing commercial power, a generator, or fair sized solar set up. The solar set up would be viable only during the day as the battery bank size and weight to keep a air conditioner working at night, again IMHO, would a bit large and heavy for the typical camper set up.

However, it is fun to make things and experiment a bit.

Cheers,

Gus

[eggsalad]

Not to spread "negative waves" but the cooling power of a couple of "blue ice" packs isn't gonna do a heck of a lot. Most folks are reporting good results with a 5,000BTU window shaker. Factoring in a duty cycle of maybe twenty percent that's about 1,000BTU/hour. Each pound of blue ice can absorb about 150BTU (or less).

So, if you have 3 pounds of ice in your device yer gonna get the cooling power of running 5,000BTU air conditioner for about 5 or 6 minutes. Then yer faced with the issue of refreezing your "ice" supply. How are you going to do that?

IMHO there just isn't viable solution to portable air conditioning (particularly in humid climates) other than a compressor driven system utilizing commercial power, a generator, or fair sized solar set up. The solar set up would be viable only during the day as the battery bank size and weight to keep a air conditioner working at night, again IMHO, would a bit large and heavy for the typical camper set up.

However, it is fun to make things and experiment a bit.

Cheers,

Gus

You're not at all wrong. This isn't for everyone. But (a) I don't live in a humid climate and (b) the places I camp don't have shore power nor do they allow the use of generators.

Here in the desert southwest, nighttime temperatures don't drop to "sleepable" until about 3AM. If I can chill the cabin down a handful of degrees for a handful of hours, that would be perfectly useful for me. And if it fails at even accomplishing that, I'm only out a couple hours of my time for trying.

[eamarquardt]

Not to spread "negative waves" but the cooling power of a couple of "blue ice" packs isn't gonna do a heck of a lot. Most folks are reporting good results with a 5,000BTU window shaker. Factoring in a duty cycle of maybe twenty percent that's about 1,000BTU/hour. Each pound of blue ice can absorb about 150BTU (or less).

So, if you have 3 pounds of ice in your device yer gonna get the cooling power of running 5,000BTU air conditioner for about 5 or 6 minutes. Then yer faced with the issue of refreezing your "ice" supply. How are you going to do that?

IMHO there just isn't viable solution to portable air conditioning (particularly in humid climates) other than a compressor driven system utilizing commercial power, a generator, or fair sized solar set up. The solar set up would be viable only during the day as the battery bank size and weight to keep a air conditioner working at night, again IMHO, would a bit large and heavy for the typical camper set up.

However, it is fun to make things and experiment a bit.

Cheers,

Gus

You're not at all wrong. This isn't for everyone. But (a) I don't live in a humid climate and (b) the places I camp don't have shore power nor do they allow the use of generators.

Here in the desert southwest, nighttime temperatures don't drop to "sleepable" until about 3AM. If I can chill the cabin down a handful of degrees for a handful of hours, that would be perfectly useful for me. And if it fails at even accomplishing that, I'm only out a couple hours of my time for trying.

I doubt that you'll be able to measure the temperature drop in your trailer to any degree of statistical significance. You're still faced with the issue of "recharging" your ice packets.

Carry on.

Cheers,

Gus

[MtnDon]

It's not really a swamp cooler. Swamp coolers cool by the evaporation of water to provide cooling. Nothing is evaporating with this concept except maybe small amount of moisture that might condense on the ice block initially and then evaporate as the fan circulates air. The cooling is simply going to be that of a few hundred BTU's as the ice block goes from cold to warm. Gus's numbers sound about right. But good luck to the low bucks experiment; I do also wonder about recharging the system though. We camp for more than a single evening when we go someplace.

[MtnDon]

When we sleep the human body produces approx 250 BTU/Hr; if we are tossing resltlessly we produce more heat than that. Awake but sedentary we produce about 400 BTU/Hr. Per person. So it would seem difficult to stay even let alone actually cool the interior without the chunk of ice approaching the size of the TD.

[48Rob]

I hope it works for you...experimenting is a good thing!

I've discovered that even in humid climates, in high evening temperatures (90 degrees+) that taking a quick shower, or bath, and then going to bed with a fan running is the best option for battery/solar only camping.

Cooling off first (the shower) coupled with the breeze (fan) gives you a head start on staying cool.
Just laying down when hot and sweaty it is very hard to get cool and comfortable, even with A/C.

After showering and laying under a fan, your ice pack cooler might really make a noticable difference, between a fan blowing warm air, and a fan blowing chilled air, especially in a dry climate where the shower would really do a lot more than it would here in the high humidity.
If it cooled for 2-3 hours, it would be enough to get to sleep, and after it "ran out" the natural temperature drop would kick in.

Rob

[wagondude]

I wonder how it would work with a small cake of dry ice in it. You would want to insulate the box to stop it from sweating/frosting, though.

[M B Hamilton]

I wonder how it would work with a small cake of dry ice in it. You would want to insulate the box to stop it from sweating/frosting, though.

Uh, Bill! Dry ice in a TD is a bad idea, it's frozen CO2.

[warnmar10]

You're not at all wrong. This isn't for everyone. But (a) I don't live in a humid climate and (b) the places I camp don't have shore power nor do they allow the use of generators.

Here in the desert southwest, nighttime temperatures don't drop to "sleepable" until about 3AM. If I can chill the cabin down a handful of degrees for a handful of hours, that would be perfectly useful for me. And if it fails at even accomplishing that, I'm only out a couple hours of my time for trying.

In a low humidity environment you can make a fine evaporative cooler out of nothing more than a wet beach towel and a fan.

Wet towel and squeeze out thoroughly.
Get nekkid.
Cover your nekkid self with the wet towel.
Point fan at your nekkid, towel draped self.
Aaaahhh!

This works until the towel dries out and you'll probably want a little bigger fan.

[MtnDon]

I wonder how it would work with a small cake of dry ice in it. You would want to insulate the box to stop it from sweating/frosting, though.

Uh, Bill! Dry ice in a TD is a bad idea, it's frozen CO2.

CO2 is great for extinguishing things that need O2 (oxygen) to exist. Things like fires and people.


Unconsciousness occurs in under a minute when CO2 concentration rises to about 10%. Remember the thousands of people in Camaroon (or where ??) who dies in the 80's.

[robfisher]

Three step air conditioning:

Take the 2 blue ice packs.
Put one under each arm pit.
Lay still and enjoy!

[Fenlason]

Three step air conditioning:

Take the 2 blue ice packs.
Put one under each arm pit.
Lay still and enjoy!

I was thinking lower...

[wagondude]

I wonder how it would work with a small cake of dry ice in it. You would want to insulate the box to stop it from sweating/frosting, though.

Uh, Bill! Dry ice in a TD is a bad idea, it's frozen CO2.

True, but you shouldn't be sleeping in a completely closed teardrop for the same reason. But I should have thought about that a little more before I posted.