Backyard Aquaponics
A place to discuss aquaponics

I know a guy up my way that has some pretty massive solar panels. Every quarter he gets a check from the power company.

Mind you his system is pretty simple because he feeds power into the grid during the day and out (off peak) at night. Basically uses the grid as a battery and overall uses much less than he produces.

I don't really have time, but basically you'll need to waterproof the electronics (potting agent) then put the fan in the water and apply power. I'm mainly not sure whether you'll get enough power to get sufficient pumping.



Yep, should work fine! Ideally you want to alternate stationary 'straighteners' with the rotating ones for maximum efficiency. A well design incompressible fluid turbine really only needs a single stage, but the extra stages in this case are because the poor impedance match between the fan motor and the water loading.

http://en.wikipedia.org/wiki/Water_turbine



I would probably do that instead by driving all the fans with a single microcontroller and using a larger solar panel - they are cheaper per peak W as they get bigger(up to a single large 80W panel or so).



You've confused power and energy (don't worry, 99% of the population gets that one wrong). 380Whours. You want this to work mid winter, so let's say 4 hours of 50% sun with a max time between suns of 3 days - you'll need to store 3 days worth (720Whours / 12V = 95Ah battery, maybe $280 for a deep cycle?) and collect say 1.5 days worth each day (360Wh *1.5/ 2 hours = 285W solar panel = ~$2850). You can derate as your budget allows.

I would be worried about the effect of a cheap non-sinewave inverter on an off the shelf AC pump motor - they really do need sine wave power to run. The 'modified sinewave' (or gappy squarewave) power will create a lot of heat in the windings and may damage the inverter.

Or, you can use a smaller, DC pump



It doesn't cost a cent for me to pull the bath plug out So every time I have a bath I'm creating $50 of wealth!



RAPS are expensive. Especially the batteries and fossil fueled generator. The grid is a great invention as it is the most efficient battery available. Anyone who has a solar array and then connects to the grid would be foolish to disconnect their solar array - use grid interactive power and get a 7% ROI!

My parents system is designed for supporting their essential electrical load, but they live in suburbia on the grid. Their system generates electricity whenever it can and uses the grid otherwise, but in the various power shortages they've had, they seamlessly switch to grid. If everyone had a system like them there wouldn't be such shortages and the batteries might be superfluous.

.........my geyser pump experimental bits are still neatly stored in the shed, see SS little design was very similar to ours - yes it was fun Janet

I haven't done any experimenting on the geyser pump -- yet -- but I think it has potential. I think slight differences in design could have major effects on the performance and efficiency. A centrifugal pump is fairly simple -- motor, impeller, volute -- but seemingly insignificant differences can make large differences in volume and pressure and efficiency.

I intend to build several models and try them. I will, of course, report my findings to the group.

Good Ems, I think I was missing something but haven't had time to follow up on it - more like Procrastinating

What is the budget anyway? That would be a good place to start.

Budget is not a major concern, of course it can't be silly.. I've been looking up dc pumps atm, here's one http://www.rockaroundtheblock.com.au/pr ... D=35&cID=8
It's 43W 24V and pumps 1700L/hr at a head of 1m, I figure I'll get it to half that head with a bit of luck but the pump probably isn;t going to handle solids at all...

I think the solar side of things may have to go out the window. It's going to work out cheaper for a larger system to run a cable out to where the system is going to be. There's just no escaping the fact that the more intensive you want it to be, the more power you are going to consume...

It is low voltage, but is it DC? It is possible to generate 24VAC from a DC supply, but it's non-trivial. Most of these impeller type pumps work with some kind of AC induction motor.



If you're going to run a cable you may as well use 240VAC.



And the more sensitive to power failure.

Yeah.... Thats one thing I will have covered to an extent. A 240V air pump with inbuilt battery backup, so that if there's a power failure, fish will have air for 8-10 hours, cheap insurance...

Not sure if the price already includes the rebate or not?

If not would appear to work out at about 600w "Grid Connect" for about $2,500

Grid Connect System

Any good ya reckon??

EB, one thing I were considering but left for later
because of the time needed to make it.

To water individual GBs, one by one,
pump water from fish tank to a header tank,
big enough for the biggest GB, with an overflow back to FT.

The header tank would have a row of siphons, one for each GB.
Only one siphon will be in ON (low) position at a time.
Others will raised above the maximum water level.

Easiest way to operate it is by a “crankshaft”.
No problem for 4 siphon loops,
5 or 6, if possible, would need pretty fine tuning.

Crankshaft turned to each position by a stepper.
Timing control should not be difficult by a picaxe.
Did play with picaxes, (before AP), but nothing serious so far.

Or the siphon loops may be controlled individually
by a stepper for each loop, winding or unwinding a belt
(shoestring or whatever) attached to the loop.

Problem envisaged:
sourcing durable soft hose for the siphons,
weather protecting the electrical and mechanical parts. SS

No problem that one SS... you can get soft durable 19mm poly from hydroshops.

Edited :

Other sizes as well ... of course....like 25mm... 13mm....

not really related but i saw an peri-staltic (sp?) pump today, i didnt realise they exisited

Cheers
pete

EB- If the energy to move the required 'cycling ideals' is too great for solar for a size X system could it not be made, on a ratio smaller to suit the available pump technology as a stand alone unit and then replicate it, also minimisizing potential for big losses.
With the ability to control the unit via coms
or is the unit the best size based on a fator?
C1

What do you folks pay per Kwh on the grid there? We pay $0.175 USD here. Anything over 40 to 50 watts on continuously, gets really expensive, or at least not sustainable and justifiable.