So I have been completely obsessing over this Aquaponics idea and I want to put some of the ideas on paper and hopefully spur some additional inputs to my thinking. Though still definitely in the experimental stage, the skills needed to grow fish in a recirculating tank system are getting dialed in to a level that fish loses are dropping to the near zero range in well managed operations. Where I see the next stage of design sophistication will be in making the system Peak Proof by dialing out the fossil fuel inputs to make the energy inputs as sustainable as the food system.
And those fuel inputs are sizable. What the Growing Power system is doing is essentially keeping 10,000 gallons of water at 78-82 degrees every hour, every day, year round. In a Hoop House. In Wisconsin. Given the BTU needs of keeping that much water 80 degrees during a 4 month Winter, I don't know of a feasible way around the NG heater at this point. Preheating the water seem to be the only workable option, and that system would then handle 100% of the heating 8-9 months of the year.
Probably system components:
- Solar Water heating with thermosyphon pumping
- Small Wind Turbine charging batteries (DC water pumps; small inverter for lights) and sized to dump excess into a heating element in a tank before the boiler.
- Running water lines through Hot Compost Piles which are also located within the greenhouse for theoretical 100% thermal efficiency. Currently looking for BTU figures for compost piles.
- Modified Hoop House with insulated North Wall
- Modified Hoop House with multiple layers of "inflated" plastic for better R values
- Dream system based on the BioShelter of the New Alchemists with passive solar elements, built into a hill. This system works best built onto an living structure. This might be the only Peak Proof Aquaponics system using Tilapia.
- Ditching the Tilapia and switching to Lake Perch. The backup system for the NG heating could then, in theory, supply 100% of the heat, reducing winter water temps to the 50-65 range. Perch can survive being frozen solid in Wisconsin ponds...
The last piece is probably the Sustainable Option. But the lose in harvest would be severe. Perch stocking rates are already a third of Tilapia, and they will not grow much in water under 65 degrees. Furthermore, Tilapia are omnivores, allowing you to grow much of the food in duckweed and water lettuce, and also giving you a better place to put your now marketable greens than the compost pile. Finally, Tilapia are easy to breed in tanks, but a Perch system puts you into dependance on the DNR. Other options would be using a methane digester to make your own Bio-Gas, or a biomass based boiler. Either of these gets expensive right quick.
Partnering Aquaponics next to heat intensive industries make allot of sense, but most small landowners do not have access to that.
Still, the system is still brilliant and I know there are ways to make it work off grid.
Please shoot me links, ideas, comments, and resources!
Labels: Aquaponics, Renewable Energy, sustainable agriculture