Okay, so my plans involve a bigger system than yours, so those variables that change with scale will need careful attention. I want to place at least one, and perhaps two fish tanks outside, on the surface.
One of these will be a tilapia and warm water fish tank, to be run at 82F. It will be kept warm one of two ways; either a warm water circuit that flows between heater exchangers at the outlets if my sealed hoods and the water tank, thus warming it, using heat pulled from the lights to do it. This would substantially reduce the load on my chiller unit, allowing it to maintain the climate while using much less power.
The other more expensive but more efficient approach would be to install water cooling for my chillers, or replace them with a heat pump. These options call for the installation of a hot water circuit, to carry the heat generated by the heat pump away to be dissipated. Instead of throwing this heat away, however, I would use it to maintain a large hot water tank of 120+ gallons for the resident's decadent pleasure, lol, and supply a heat exchanger coil in the hot tub- for more of same, lol- and another coil to warm the fish tank, more to heat the entire house, and finally through a waste heat radiator for whatever heat might be left!
The other option is to run the fish tank at 55-65 degrees, with cold water species like trout in it. This water would be cooled by the chiller along with all the other RDWC, so it would require extra power to keep cool during hot summer days. There are jetpumps and other options for keeping the tank cool as well. Of course the tank would be insulated and shaded from direct sunlight to minimize such heat gain as much as possible. The payoff comes in the Winter time when that tank, sitting outside in Colorado, would freeze solid if left alone! Instead, the chiller coil continues to run, drawing heat out of the chiller system and maintaining the tank at temperatures very comfortable, even balmy, for the fish. This heat sink effect could also be increased with the use of jet pumps, fountains and the like. I can see a setup like this eliminating the need for several Tons of cooling capacity, and that's being very conservative considering it can get flat bone chilling cold around here!
I know this goes way above and beyond aquaponics, but I believe the promise of this dual approach is the free lunch you get by using each part of the system for multiple benefits. The tank(s) will still have fish, they will still eat fish food and create biosolid waste and ammonia, which will feed by gravity down into first a settling tank and then a big bio filtration bed- I like the worms, I'll get some, excess becomes fish food!- and then this water will flow through any of multiple RDWC I already use. From these, the water will drain into a big sump tank- think kiddie pool on the floor in the basement, lol- and a 1/2hp pump will push that water back up, outside, and into the fish tank to pick up more waste and solids and repeat its journey.
Ambitious? Yes... but how much more complexity am I introducing? A warm water circuit, which would eliminate the need for outside power for nearly any heating function on the premises- save actually baking the fresh fish in the oven!
