Maybe this has been discussed before, in which case excuse my ignorance (I did do a quick search but discussion appeared to only be about heating & cooling water).
To me, the weak link in AP is definitely relying on an electricity-driven pump. I know solar panels, batteries, generators, windmills, an exercise bike with a drive belt attached, etc. could and most probably are being used as backups for times when the grid goes down, but wouldn't it be great to not have to rely on electricity at all?
Does anyone think it would be possible to use thermosyphoning to distribute water around the system instead of a powered pump? As in somehow rig up a system using heat exchangers so that water can be moved due to the heating and cooling of it (you know, heat rises and all that...) I guess the temperature changes wouldn't be too good for the fish or plants, though.
OR
How about Thermofluidics?
Don't know much about it, but check out
http://www.thermofluidics.com/ and click on the "Technology" tab!
I haven't really had a good look at it yet (and even if I had I probably wouldn't understand it!) - a friend sent the link a while ago by coincidence.
Here are some snippets from the site in case it doesn't sound very appealing yet:
... Also, we are concentrating on NIFTEs because of their capability of operating across low temperature differences...
... Apart from unprecedented reliability and low maintenance, NIFTEs can be manufactured from very low cost materials using cheap and well established production techniques...
... NIFTEs are capable of pumping many different fluids, from shear sensitive biological cultures to viscous and chemically, or mechanically abrasive media. They have a gentle pumping action, and operate in almost total silence. NIFTEs can be tuned during operation to suit a range of different pumping head and flow requirements, and available power sources...
... Low grade heat is associated with low temperature differences, and we are interested in the utilisation of low grade (e.g. solar) or waste heat because we would like to extract as much useful energy and perform as many useful tasks as possible while saving fuel, as well as to use sources of energy that would otherwise have been lost...
... NIFTEs can also use cool sources for power, taking their input heat from the ambient environment. They are capable of adding or taking heat from the fluid which they pump...
Hmm... take a look at the "Applications" page - even mentions irrigation, garden pumps, filtration pumps and aquaculture!
Obviously also great in terms of self sufficiency and cutting down on waste!
Taking into account all the other novel and surprising and ingenious ideas many people on this forum have come up with, I'm sure something can be adapted/expanded upon to suit AP...
Backyard Aquaponics
