Backyard Aquaponics
A place to discuss aquaponics

Just had an idea.

It is only an idea and has a lot of wrinkles I am sure.

I am an IT person, so this is for everyone smarter than me to help flesh out.

OK, this system would require a LOT of water storage (2 x 10000Lt tanks), and a decent HEAD from tank 1 to tank 2.

So, the idea is this.

(ascii art comin up)

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|_WT_|
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|_FT_|
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[_GB_]
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[_GB_]
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|_WT_|


So, we start with a hugely over-size tank at the top of the slope (enough to keep the gb's in water for a minimum of 12-18 hours) with a slow outlet at bottom of tank - this tank can drain completely if necessary

Water flows downhill into Fish Tank (CHIFT)

and then into GB's (as many as required)

And then into a lower sump tank capable of holding all water in system

Then we place powered pump, with wind or solar (or both) to drive it (even a windmill could do it) and it would pump from bottom tank to top tank as long as it has power or wind, (6-8 hours per day) (more on a windy day)

effectively pumping the sump to the header and allowing for continued overnight operation.

Anyway just a though - fire away at it with ideas/critiques

Aj

Oh, and some sort of water wheel to power the pump back up? it would not have to be 100% efficient, but any water going up from the wheel movement is essentially free?

Would be possible in a windy location but you would need a large sump to cope with the slower return pumping time. Also an electric sump pump in the sump tank that is triggered by high water level. Increases water capacity does effect nutrient load so that would need to be taken into account. Also, many recommend turning the water in the tank over once every hour, this would not be possible using a windmill with large tanks.

Stadndard indmills are not cheap so unless you had a spare one laying around and a big block to put it on I am note sure it would be feasible.

Solar pumps are fairly weak unless you get a big (expensive) one. My neighbor has one pumping up a 8m head from his dam to a tank for garden water which takes around 10 hours to fill 2000L, obviously it would fill quicker if the head was not so large

The idea I guess, is to have enough volume in the header tank to run for a while at a slow drain, whilst having enough "alternative" sources of pumping, to be able to reliably run off grid. - ie: Solar, Water Wheel, Wind Turbine (even wind powered electric) - or run the solar/wind into an inverter/battery system just so long in the day to top up the header tank.

I understand that changing over the water in the FT is important, and that tuning the flow would be critical, for correct operation, but I reckon that given enough turnover, constant (remember some people turn off water flow at night) water through the FT and GB's would allow for this.

The Idea is to run as efficient a pump as possible (or 3) so as to utilise what resources are available (in this instance, wind, water and solar)

anyway - just a thought, and probably a *LONG* way off for me.

I get decent winds here in afternoon, and EXCELLENT sunlight all day on a sunny day, and the water wheel would turn as long as the water was moving (in theory) so i thought it might be an idea to try.

Any other self-sustainability nuts (given that I am the biggest nut here ) have any comments?

I looked into a large header tank but more for DO. The idea being that it was filled and overflowed into the system. When the power went out it slowly drained.
You could still use a header tank but keep it just above the GB's and the sump just below so the hight only ends up a couple of mtrs so a solar pump would have a better chance to move enough water.

I'd be a lot more concerned about having the GBs flooded for so many hours

They can still have a siphon to flood & drain them.

actually, someone had an elaborate (Cyara? IIRC) sketchup file which was showing a terraced aquaponics setup.

where each level drained to the next, so they had FT GB GB FT GB GB SUMP (for example) all terraced one below the other.

So the idea is, from top sump, or header, control the flow down the terrace, to a Sump, utilising SLO overflow for fish tanks and some sort of siphon (you choose) arrangement for the GB's all the way down to the sump.

The idea behind this is to use renewable resources to get the water back up the hill.

The free electricity is not free really, as you have to pay for the generation to get it started.

However, if we have siphons working, the outflow from the siphons would be enough to turn a water wheel, which generates *some* electricity to charge a battery system, and this should work even on more level sites.

It could also have a solar panel or 2 to charge a battery system\

It could also utilise wind where available to also charge this system.

The idea being that very little, (if any) GRID power would be required.

I was always intrigued by the possibility of using siphons etc to try and move the water back up the hill to the top of the cycle in a way that used as little GRID based resources.

I read on here somewhere that the biggest problem facing people in 3rd world with a setup like this, is ELECTRICITY - to move the water to top of cycle.

Also, another pump could be an air operated lifting pump, although where we could generate enough compressed air to do any serious lifting I don't know.

Anyway, it is interesting to see what people think..

The water turbine would not be more than 70% efficient so you would need 3 times the energy to pump the head load and 2 times the volume of water you might be thinking off.

So if you have a 100 watt turbine you would need a 300 pump and solar system to pump it. You also need a reciprocating ram pump, not a spinning impeller.

Spain uses capture storage much like the Snowy River scheme. When Sydney needs air conditioning Jindabine opens the gates and the turbines turn. When that water reaches the bottom after the power station its held in a dam and pumped back up (1.3kl) to Jindabine. It uses Hazelwood (Brown coal) energy to achieve that and it takes nearly 5 times longer and 3 times the energy to pump ot back up.

In Spain they use majority wind energy.

But don't expect Australia or the US to be so clever.

For small scale I would try an air storage system.
Using an air powered motor (tata motors have a good one) you could run a 2kw solar powered electric 20 hp air compressor ($70 auto pro) into a rather large 200lt air tank. that would store an equal amount of "work" for the 8 or 10 hours of darkness.

The air motor is actually efficient at 90% so you only loose 10% of the work energy.
Then power your pumps that way.

Cheaper than batteries and if underground its silent.

OMG that is so wastefull

i could understand gettin power from the turbines if they were using the water anyways but to pump it back up the hill is just dafft
Cheers
pete

If it used a handful of really big wind turbines on nearby hills it would be ok. The dam then becomes a battery and charging batteries is not so efficient either.

Funny thing is at least where Melbourne is concerned, most Air conditioning and heating (electric) is done on the windiest days.

Is this like perpetual night motion???

I wouldnt bother with trying to make the hydro electric part of the scheme because I dont think you would generate enough power to pay for the generator. But the rest of the plan I think would work. I think the dollars you might have spent on the hydro electric generating might be better spent on more windmill or battery storage (electric battery or just more water at the top of the hill to get you through the windless days). Having a decent header tank seems to work well for nature. As long as the final drop into your fishtank created enough oxygenation, everything else should work itself out.

I think the amount of nutrient in ppm would be roughly the same in a system with a zillion gallons or 100 gallons once the system had some time to mature.

As far as I can tell a given number of fish convert a given amount of food into a given amount of toxic muck. I dont think it would matter all that much if there was a few times more water than normal. Eventually it would all be as nitrate rich as that amount of fish and food and plant would settle down to. I think oxygen would be key.

But...

If you are using uphill storage as a battery, you also have to have a lot of downhill storage. The system would work by having a stack of water pumped up the hill saved up, so on windless days you could keep the flow. But the flow needs to go somewhere. 3 windless days in a row is a stack of water flowing through you system, which is a stack of water eventually arriving at a sump tank. If nothing is being pumped back up the hill for a few days, that requires a pretty big sump.
For my small test blue barrel system -> 100 litre FT + 100 litre sump, that would mean 7000 litres at the top of the hill and 7000 litres at the bottom to run it for 3 days without pumping if I wanted to maintain my current turnover every hour.

I just made up the number of "3 days without wind". perhaps there are never 3 days without wind, but it might be better to work on 1 days storage and some form of mains connected support for those freak times when your system is in the doldrums.

and this ...

pumping water back up into a hydro dam is probably a reasonable method of storing power given the inefficiencies in running a coal fired power plant mean there is often excess power that has to be dumped - we dump ours into our estuary in south oz in the form of hot water. Yeah, nature loves it when you do that. But if there is no hurry to refill the dam and you are using waste energy, or better yet using wind or solar, its probably the lesser of two evils. In fact it might end up being the best way to make wind and solar all we need for baseload power.

Or not