Step 3: cooling off a tear drop trailer
-install the heater core where you want it, I plan on having mine installed near the top of the galley wall in the galley, with a vent into the TD sleeping compartment.
-mount your 12 volt fans so they blow through the heater core. I plan on one fan bringing in outside air all the time, and the other recirculating air from inside the TD.
-mount a drip pan underneath the heater core with a drain line back to the cooler.
-run the wires from your 12 volt power source to a switch or two. I plan on having my TD have two fans both running continuously, one bringing in fresh air the other recirculating TD bedroom air, and a wall thermostat switching the 12 volt pump on and off. This may exceed the amps rating for a normal wall thermostat but they also sell 120/220 V wall thermostats that will work.
-run the plumbing from the heater core to the cooler and clamp the ends if needed.
-zip tie everything in place as needed.
-fill the cooler with ice or ice packs, I use juice bottles full of water (fill 3/4 full, dump in salt and shake until the water won't absorb any more, put the lid on and freeze with the bottle on its side) leave a space for the pump (I plan on making some sort of baffle to keep ice away from the pump )
-put in enough water to cover the top of the pump.
-put the the cooler back together, turn it on, check for leaks.
-enjoy hours of cool air in your TD.
since a TD is mostly used inside for sleeping, a cooler full of ice should last the night, however you will probably have to refill the ice and dump out most of the water from the night before. Since most campgrounds, and gas stations have ice for sale this shouldn't be too hard.
I have posted this idea on tnttt.com and one guy has tried it, http://www.tnttt.com/viewtopic.php?f=29&t=18104&hilit=rowerwet&start=15 the guy who tried it is near the bottom of page 2 of the thread
his quote " I used 10lbs of ice and it lasted about 5 hours at 88 degree's outside, my Tear maintained 76 degrees." He goes on to give ideas on how he wants to improve the design using a copper coil inside the cooler instead of a large bath of water, to do that though would require some sort of reservoir for expansion of the water, not hard, just a little more details, is all.
just like my other I'ble on how to heat a TD or tent off the grid, this gives a way to cool a TD off the grid. In fact ice was around a long time before refrigerators, my parents house is built in the area that an ice house once stood hundreds of years ago. During the New England winter ice was cut out of the pond behind their house and packed in straw and saw dust in double walled ice barns, the ice was even shipped all around the world in old sailing ships packed in straw and sawdust to be sold.