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The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.
Does anyone have any experience with this air cooler? The Admiral wants to keep the cabin temp around 70 - 75 at night... http://www.kooleraire.com Derek
Derek Crawford Chief Measurer C25-250 2008 Previous owner of "This Side UP" 1981 C-25 TR/FK #2262 Used to have an '89 C22 #9483, "Downsized" San Antonio, Texas
I have no personal experience, but I'd suggest doing a bit of math regarding BTUs of energy vs. pounds of ice melted into about 50* water. This could be the answer to your prayers, or you could need a truckload of ice to make it through a warm night at anchor. You'll note that the website is conspicuously vague about how much ice cools how large a living area with what R-factor insulation at what outside temps, for how long, etc. Being able to precisely aim the cold air is certainly a plus -- you could specifically cool your berth without having to first cool the entire rest of the boat. (Or maybe you could use those protective Tyvec bunny suits for pajamas and run shopvac hose directly into them from the KoolerAire. )
For that price, what have you got to lose by giving it a try? Of course the rest of us expect a detailed report on how well it works, including fessing up if it's such a scam that it belongs on late night TV ads for $19.95.
For those interested in testing the theory for less than $40, you could jury-rig a proof of concept prototype using a 12VDC computer fan, some duct tape, and a sheet of cardboard or scrap plywood. For that matter, trim the plywood to fit your large ice chest, coat it with WEST resin, screw the computer fan to it, add a few feet of scrap lamp cord, a cig-ltr. plug, and save the $40 for ice.
Anybody ever try drawing cooler water up from below the thermocline?
Seems like with a fairly modest current draw you should be able to pump up fairly cold water and mist it on the deck to cool the boat down or perhaps fabricate some sort of swamp cooler. Would draw a lot less energy than 'conventional' cooling. Of course, it wouldn't work in all waters... you need enough depth to tap into cold water.
Frank - we don't want a conventional A/C - neither of us enjoy an ambient temp of less than 70 degrees! (and that is the bare MINIMUM!!) Clam - the lake water temp in August is 85 degrees and there is no thermocline in the marina (it's only 23' deep!) Leon - if you can run the figures on the physics of this device it would help! Derek
I'm thinking it won't work real well, but I could easily be wrong. The 'testamonials' indicate reasonable effectiveness. It's certainly not like dropping $800 or so on a marine unit.
The thing basically looks like a swamp cooler that relies on the latent heat of fusion rather than the latent heat of vaporization like a regular swamp cooler. The key to understanding this is understanding the latent heats. It takes almost as much energy to melt a gram of ice as it does to take that same gram in water form and raise it to near boiling (ie, the latent heat of fusion is 80 cal/gram-degree C). In contrast, the latent heat of vaporization for water is 540 cal/gram-degree C, or almost 7 times that of fusion. This is the first reason swamp coolers work so well <i>with low relative humidity</i>; evaporating air absorbs <i>a lot</i> of energy. The second reason is that dry air is easy to heat or cool; raising the humiditiy raises the air's specific heat and it takes much more energy to heat or cool.
The math/physics would go in two steps, the first of which is easy, the second is not. First calculate how much energy would be absorbed by melting a given block of ice knowing the blocks mass and intitial and final temperatures (you might also add in cooling due to evaporation in the process). Next we'd calculate how much the air temperature would be reduced having this amount of energy removed from it, but this would get rather complicated because of the number of variables involved (mass of air, specific humidity, specific heat of air at that humidity, proportion of energy cooling air vs sailboat, other energy losses/gains, etc., etc.
I didn't really mean to wax didactic, but I thought someone might be interested in the science involved; if I made any errors, feel free to correct me.
I bet the inventors did what Leon said with a computer fan and cardboard - I may try it myself this summer, depending on several as yet unknown variables ;~)
Notice: The advice given on this site is based upon individual or quoted experience, yours may differ. The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.