# My $25 Swamp Cooler...



## travlin-easy (Dec 24, 2010)

A few weeks ago we were debating whether or not a homemade swamp cooler would cool a mid sized boat during really hot weather. Lots of pros and cons, but after researching the cost of construction I decided to give it a try.

The cooler chest is a good quality Coleman that was purchased at BJ's Wholesale Club as a closeout for $12.95. It's a 36-quart cooler chest that came with a small 6-pack chest at no additional charge.

The fan, a 12-volt, 120-mm computer fan with 4 blue LEDs was purchased online for $6.99 with free shipping.

Another $4.99 went out at Radio Shack for a universal, 12-volt cigarette lighter plug.

I had some scrap paneling in the shed and lots of scrap speaker wire in the workshop, which rounded out the parts needed for construction.










About 18-pounds of ice was placed inside the cooler chest. A 7-pound block, a 6-pound bag of cubes, and another partly filled bag of cubes that probably had about 5-pounds in it.

The boat's cabin was about 84-degrees when all the hatches were shut and the swamp cooler fired up. The fan is dead quiet, and within a few seconds the air emitting from the vent holes was ice-cold. The blue LEDs served served as a great nite-light and provided a soft, blue glow in the main portion of the cabin. This turns out to be a great asset for old codgers with BPH that have to get out of the sack and visit the head a couple times a night.

It took about 2 hours before the cabin temperature was a comfortable 72 degrees. While I waited I watched the second half of a pre-season football game on the flat-screen TV. As anticipated, the humidity remained quite high inside the cabin, but at least it was cool enough to sleep comfortably. I have no way of measuring the humidity, so I don't know if it increased, but at that point I really didn't care.

At 4 hours the temperature had fallen below 70 degrees, which was just fine with me. I had to use a light blanket to keep warm. (Old folks get cold when the temperature falls below their age!  That's why we go south in winter.) :laugher

The ice lasted about 5 or 6 hours, but the air coming out of the swamp cooler was still relatively cool because the water in the cooler was ice-water. It took about another 2 hours after the ice melted for the water to warm to the cabin temperature. By that time I was cooking a cheese omelet with some chopped, sauteed onions and mushrooms to go with my English muffin and a couple strips of bacon. The stove, obviously, caused the temperature to rise a couple degrees, but it was still comfortable in the cabin.

*Conclusion: * The swamp cooler is by no means an economical method of air conditioning the cabin. It can, however, make life a lot bearable on those evenings when there's not a breath of air blowing where you're anchored up for the night and the temperature and humidity are in the mid 80s. I DO NOT believe it would be beneficial to use it during the day - it just couldn't handle the sun beating down on the cabin and hull. There are other benefits, though.

The swamp cooler can still be used as a cooler chest for keeping the booze and food cold. Additionally, the computer fan insert can be used as just a fan. It can be propped up on the opposite side of the Vee Berth or the far end of a quarter berth and used to circulate the air. The fan draws 0.41 amps, which is negligible and the turbo blades move 2.7 CFM of air, which is a fair volume for such a small fan.

The Swamp cooler will definitely be going with me to Florida for the winter. Last winter in Marathon's Boot Key Harbor was pretty darned hot during February and March, so I think it just may come in handy.

Cheers,

Gary


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## MedSailor (Mar 30, 2008)

Looks great! Nice work! Since many (most?) boats carry a cooler of some sort aboard already, all one needs is the wood, fan, and plug and you would have a way to make the boat comfortable on those stifling hot days. Just add ice. 

Tell me about the holes. Are they just to allow air into the cooler? Anything else we need to know before making our own? 

I'd be interested to see block vs crushed ice experiments to see which works better.

MedSailor

PS You should add this to the "low buck projects" thread.


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## travlin-easy (Dec 24, 2010)

The fan draws air into the cooler, which passes across the ice, then exits via the two holes at the other end of the piece of wood. I'm sure the block ice would last considerably longer than the cubes, and the while the surface area of the cubes would be a bit more, the advantage of block ice lasting longer may offset the difference in surface area.

Good Luck,

Gary


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## Skipper Jer (Aug 26, 2008)

Give any thought to adding baffles to direct the air around the ice? Maybe a thermostat to shut the fan off once the temp has reached the desired point. That might make the ice last longer. Great project, thanks for sharing.


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## SloopJonB (Jun 6, 2011)

I have no experience with swamp coolers but I've had great success using frozen milk jugs of water rather than "bare" ice in coolers. Would they work in this application? It would cure the humidity problem if it did.


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## Barquito (Dec 5, 2007)

Sounds like a great idea. Definitely post in the Low Bucks Project thread. I think, however, the technology is a little different than a swamp cooler. Swamp coolers operate by evaporating water.


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## miatapaul (Dec 15, 2006)

I thought swamp coolers used evaporation (really only useful in the desert) not ice. I have seen people do set ups like this with a copper line feeding in and out of the cooler and then spiraling on the front of a desk fan, then use a fountain pump to move water, gives a bit more control of the area being cooled. The other advantage of this system is that it does not add humidity to the air. I have even heard of running cold water through the system from the tap (such as in an apartment that had water included in the rent) worked for me when I had an apartment that had well water. A third set up (for a boat) was to run a weighted hose to pull water from as deep as possible beneath the boat and run it through the coil in front of the fan and cycle the water with a small 12 volt pump. If you are not too far south and have deep water, this can supposedly work well. Kind of like putting beer in a mesh bag and hanging it overboard to cool it.


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## Barquito (Dec 5, 2007)

> If you are not too far south and have deep water, this can supposedly work well. Kind of like putting beer in a mesh bag and hanging it overboard to cool it.


Or, just skip all the fan and coil stuff, and drink the beer


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## misfits (Dec 9, 2011)

As some have noted a swamp cooler is an evaporative cooler & is meant for dry areas of the country. They don't work in areas with high humidity.

Interesting side note to Gary's yankee ingenuity. The measurement for a/c is commonly refered to as tons. A ton of a/c equals 12,000 btu's. In the days before modern air conditioning, people cooled thier homes with ice. The term "ton" back then was the measurement used to determine how many tons of ice melt within a 24 hour period while cooling a space. 

This past summer sure felt like a 4 ton day


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## AlaskaMC (Aug 19, 2010)

Very "cool" idea! Baffles forcing the air down and up a couple times would definitely help. You could attach them to the top panel in grooves so that put together it would just slide into the cooler, but they could be removed so the panels would store flat for using the cooler for beer (oh yeah, and food).

Now all you need is a slip in front of a dockside hotel with an ice machine.


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## jrd22 (Nov 14, 2000)

Good job! Nice work Gary, that's going to come in handy in Fl.


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