Homemade evaporative ac system with amazing results!!!
 

I have been researching this topic for sometime and recently started building it, i started a thread on this topic and had lots of responses, just wanted to give update. This unit is built on a 48qrt cooler. It uses a 12"x12"x4" evaporator out of a lexus i got from work. It is built into a box at a slight angle with a blower motor case mounted in the rear which has an air cooled resistor with 4 speeds. Under the front of the evaporator is a drain I made from cutting pvc pipe that drains the dehumidified water back to the cooler. The ice cold water is fed to the evaporator via a 600gph bildge pump from walmart. I tested this unit out this afternoon after work. I put two frozen water bottles as well as one frozen mil jug and the rest crushed ice. I have a pq 290 enticer and the cabin was 98 degrees with ambient temp at 90. I started this unit on high the whole time and found outlet duct temp at 40 degrees via infra-red heat gun. Now...within 30min the cabin dropped to 65 degrees and i noticed the evaporator had water pouring off of it from the moist air moving through it. It ran on high for 2hours at this time all the ice was melted other than the frozen water bottles and milk jug, the water was still very cold and duct temp was at 55 degrees. This is an amazing temp drop and reduction in humidity from a home made air conditioner. If i use all frozen block ice and regulate the blower speed to low or off as needed, I believe i can have cold air all night long during overniting. I am amazed of the results. There are comanies that sell these much smaller units for $500-$600 for mainly small aircraft, and Im certain the evaporator is much smaller. I have seen some of these built on youtube with a heater core, the problem is they are too thin and will not disipate the heat like a thick ac evaporator will. I will complete the wiring with all blower speeds and do a amp draw test on the unit next time. I will try to post pics and do have several phone video clips of it running but don't know how to post them. so....what do yall think?? Im very impressed concedering I only have about $60 bucks in the whole thing and it cools the cabin down cold and fast!!

Good work!!!

"cool" post pics....

Thanks guys...I will take some pics and try to get them posted in this thread.

Sweet!!

Great job! Pics!!

Agree, pictures required!!!!!!

very nice, pics would be cool, (No pun intended)

What about useing dry ice instead of cubes. Or what about Blowing air over a block of Dry ice and exit out of cooler with registers. Hmm:coolcowboy:

The problem with dry ice is that when it "melts" in a confined space it will kill you.

Great!! Remember, as long as you keep the water circulating through the evaporator below 50 degrees, you have a true AC unit. Basically you created a chilled water system like they use in large buildings. Chiller provides the cold water used to cool spaces. Your chiller is the ice cooler.

I would now incorporate a thermostat to turn the pump and fan on and off based on cabin temp :)

You might also want to use your experiment and try it on a smaller cooler. You will get the same results however will need to replenish ice more often. Might be worth the trouble to replenish ice rather than a 48qt cooler.

I remember something about dry ice gassing off something bad. Oops:eek:
Thanks

dry ice is just frozen carbon dioxide...not a good choice.

WHere will you store the ice while 48qt is being used, anouther 48 Qt. Seems bulky to me. You can always use your genset to burn fuel to keep freezer cold. Waste of money again.
I like the 12 volt stat Idea you have, that would conserv the ice longer. If you could get block ice it would last longer maybe, still very economical idea for AC.
Great idea, just condense overall picture.
My 2cents:party-smiley-004:
B38

Great! Glad it worked out. Also like to see pics.

But wasn't your original topic all the lines of limited space?
A hatch air is about the same size a a 48qt cooler. Only need a small gen, which would not be limited to AC use only and no need to store ice. Providing $$ isn't a driving factor.

sounds like your onto a marketable product

nice work.

I am very interested in this as a winter project. I have no hatches, so hatch air doesn't work. I'm not really hip about lugging a generator around either.

the biggest drawback for me, would be finding a way to store the ice all day till at night, when I am ready to crash, without having it melt.

Very interested in your thread. Great job!

Very sweet! The term i have generally heard for this type of unit is a "Swamp Cooler" The dry ice is not a bad idea... It lasts a VERY long time but you might want a place to vent the c02 from the dry ice evaporating so you dont push all the oxygen out of your cabin!

Not worth betting your life on it working.

a "swamp cooler" is just an evaporative cooler and not a true AC unit. Evaporative cooling is huge in the dry climates (AZ) where the ambient air is so dry. Swamp coolers in humid areas results in nothing more than cool WET air (Lowering temp but not removing moisture). True AC removes moisture and cools the air.

Guys, I mainly intend to use this at night. I plan to use just block ice because it lasts longer. Im gonna keep it in my spot for the frige and hopefully the ice won't melt too much through the day and if so, i will get some ice and top it back off from a marina. Money is somewhat of a factor and don't really like the idea of packing a genn and gas can around at this time, plus got the cost a the ac unit itself. Maybe will look into the idea later down the road. With the cooler in the spot where the frige usually is, its not in the way at all. Think about when you pack a cooler for the day, you are in and out of it all day and a day later its still very cold and maybe still has ice in it. Im thinking the ice really isn't gonna melt too much unit you start running the unit. I still have to wire in a 4speed switch and the resistor but will take some pics and try to get them loaded tonite.

Bring that invention to the poker run next month, I'd like to check it out.

You can get all the State Dock Cooler Scooters to convert their coolers to double duty! :)

I have pics but cant figure how to get them posted to this thread?? need help!

I have the pics posted in the "photos" section on the main menu...enjoy. tell me what yall think??

Good job! nice cold water system, you could stash the evap unit somewhere inside the cabin place the cooler and pump in the engine compartment , or somewhere else out of the way. the controls would be a snap . you could use any battery operate thermostat from home depot to control the pump and a rotary switch to control the fan. good idea using an icebath though.

That is very similar to the system that Concept uses in their boats. I don't remember the brand, but the same idea.
Good job.

Found a picture.

this system was actually installed inboats??

Yes, it seems to work the same way that your system works.

I need to explore other means of keeping the ice frozen longer, maybe the guts out of a 12v dc frig. Do you know exacely how these system work that are installed on boats, still have to add ice?? curous about the set up??

You do have to add ice. I found this system also http://www.swampy.net/boat.html

Instead of the resistor for speed control, find a PWM speed control like this >

http://cgi.ebay.com/PWM-DC-MOTOR-SPE...item3cb9eee6ad

Much more efficient

those units look great but mine looks even better concidering i only have 60 bucks invested and it will freeze you out!!
!!

what about putting either rock salt around the ice to keep it cold? old time ice cream makers used to put rock salt on the ice and it made the ice even colder and last longer.

Rock Salt

Adding rock salt to a slurry of ice and water lowers the temperature at which water freezes. If you added rock salt to a glass of ice and water, the ice would melt more slowly, and the general temperature of the water would go down. The reasons for this are somewhat complicated, but this simplification gives some of the pertinent details.

Basically, for ice to melt, energy must be drawn from the surrounding solution to break the hydrogen bonds that keep the ice frozen. The energy that's taken is in the form of heat, which is why ice makes the solution that it's in cold, since it's taking the heat to melt. Salt upsets the balance and makes the melting rate slower, because the ice requires more energy to melt. This draws more heat from the solution, which results in a larger temperature drop.

Congratulations on your results, I'm not hating, It is a neat concept for sure. I have no doubt that they work till the ice melts. This system, while effective will require constant monitoring...do I have enough ice? will it get me through the night...etc...I just think it would be comforting to have cold A/C and a little extra power when on the hook, on demand. I appreciate your inventiveness and enthusiasim with this project. However, it's capabilities are limited and I'm sure they have been looked at over and over again by people much more intelligent then us. There is only so much energy stored in a specific amount of ice. I also love that your cheap, I'm the king of thrifty. If you don't want to spend the loot on a honda generator, then a small 2000 watt generic generator (honeywell, kipor, ryobi, etc...) could be had for maybe $200+ used, along with a used a/c unit. You don't have to mess with gas, you already have enough of that on the boat. I'm always concerned with CO. So a dectector (or 2) would be required. Add a small removable extension to the generator to get the exhaust at or below water line and there you go....The one other idea that I had was to use an in room air conditioner, permanently mounted with the outlet ducted to the cockpit or something....that would be trick, without having to pull an a/c out and set up each time you want to be cool.

PS - I think that is really a cool idea - pun intended :)

Drillin, you are correct that the salt lowers the freezing point of the solution however it does not make it melt more slowly. Yes it will lower the temp, but the ice melts to do it.

yes you are right about the ice cooler, it isn't constant and probably will not last all night. I have been looking at other genns like the generac...I am finding them new for about 650-700 bucks. They are still really nice genns, having no luck in finding a used ac unit though. Im not too fond of the idea of having to pack a genn around all day and have it running sitting on the swim platform. I would love to have something more perminant on the boat but I don't have ANY room to mount a genn. I do have plenty of room for a nice ac unit in the cabin though. Maybe I should just step up to a nice big cruiser so i can have all the comfort features of home. I have two younger children, and would like to have the cabin comfortable to be able to watch a movie or take a nap during the day while mommy and daddy enjoy the sun and cold beverages.!!

My buddy bought a honda 2000 for his formula 27pc for about $500. They are supposed to be ultra reliable (I don't doubt that). If you check out The Hull Truth, there are a lot of guys whole run them instead of there onboard gensets to save them because they cost so much and do require more maintenance. They Hondas also sip fuel and I couldn't believe how quiet they are. One guy said that he went cruising in the Bahamas or something for an extended stay and couldn't believe how many he saw. I have a 7.3 onboard, and even with two a/c units I have never even loaded it near it's capacity. I stay on the hook alot and I made it 8 years on the chesapeake without a genset, just fans which made life bearable. My slickcraft seemed to magically stay pretty cool on it's own. BTW I can sell it for a song with trailer...great boat, made by tiara

honda 2000?? new or used? I havent seen them for that low of a price!

Thats a great idea, thanks for sharing.
I always wondered if you could pump the lake water through something like that since our water doesnt get past 70* up here.