As requested a fairly easy DIY project for effective energy efficient cooling.
The idea is similar to simply running a fan over the water surface. However with this method you're increasing the surface area and contact time between the air and water. In addition it presents the ability to vent the exhaust humid air outside or to a more appropriate location.
It's efficiency is based mostly on the humidity of the air fed into the cooler. The less moisture in the air the better it will work. However the water and air flow should be controllable as it's important to be able to control contact time in order to tune the cooler.
This is one I built myself. More as a prototype, once I figure out what will work best I'll redesign it and likely build it into my new sump.
I designed to fit in the new cabinet.
I built it from clear acrylic, you could use various other materials. Next time I would use mostly black acrylic to prevent light and algae growth.
I connected a 3" PVC pipe line to connect the cooler exhaust air to an outside vent. I also ended up mounting it a little lower than planned for better water flow.
I'm still working on the final design. As it stands it can produce about a 4 degree temperature drop from 84 to 80 degrees on an average day.
System volume is approx. 200g
628W of lighting
2 reeflo pumps
Everything is pretty sealed up and has little exposure to the surroundings for heat exchange.
On the really warm days my place has been getting up to 26 degrees C indoors. It has also been fairly humid lately so the cooler has only been able to drop the temp to 82 degrees. If I run the air conditioner to keep the room with the tank only (not filtration) at 23 degrees C the cooler will maintain about 80.2 - 80.7.
Ideally I would like the new design to maintain the tank temp at 80 without having to run the AC.
I'm open to questions and suggestions.