The Otherpower discussion board

Remote Living => Water => Topic started by: OperaHouse on November 25, 2017, 12:32:33 PM

Title: Solar Powered Pond Aerator
Post by: OperaHouse on November 25, 2017, 12:32:33 PM
I've been following some posts on pond aeration and thinking people are trying to turn this into a monstrous costly problem. Found a video from Missouri Wind and Solar (not a big fan) and they demonstrated a 100W panel, $4 ebay buck converter and a 400W inverter. running an air pump.  They further went on to show how a cloud passing over would send the inverter into low voltage shut off.  This can not be recovered from without turning the inverter off, rendering this useless as a finished design.  Then they went on to say they added a relay and the whole system worked flawlessly.  They would give information in the next video. In the second video this had turned into a product you had to buy.

I would like nothing better than to turn this into a microprocessor project.   I couldn't get that "relay" out of my mind and if they are smarter than me, it is time to pack it in. Here is my low tech solution.

1. Use a 280W 30ish volt grid tie panel because it is cheap and their pump was a little smaller than most people use.

2. Connect that to a 24V relay with a resistor in series that prevents the relay from closing until about 35V is present.  Relays have a wide hysteresis and the voltage has to drop to about half before it drops out.   The solar panel connects to the moveable contact and the buck converter to the normally open.  The normally closed connects to a load resistor that would simulate some of the load of the motor.

3. When sufficient power is generated by the panel to run the motor, the relay pulls in and powers the buck converter which in turn powers the inverter.  A 10 or more amp buck converter would be sufficient that can operate up to at least 40V on the input.  These shouldn't cost more than $20.

4. That buck powers the 12V 400W inverter.  I would probably add a couple 1,000uF electrolytics to handle the ripple current. Those buck converters have just enough cap to keep them stable and cheap.

So, when a cloud comes and before it goes into low voltage shut down, the relay will remove power to the inverter. Some playing around with part values, but it should work.  Sounds fun and almost makes me want to dig a pond.
Title: Re: Solar Powered Pond Aerator
Post by: Mary B on November 25, 2017, 02:38:17 PM
Why not find a 12 volt air pump and power it directly from the solar panels?
Title: Re: Solar Powered Pond Aerator
Post by: SparWeb on November 25, 2017, 02:54:02 PM
Is there such a thing as a DC pond aerator pump?  (No I couldn't find any with a quick search myself)

The resistor dropping 10V on your relay coil will be dissipating a few watts all the time, and the buck converter will also be wasting a bit of power, but probably not a lot, in the grand scheme of things.

I have several neighbours with ponds that they aerate over the winter to keep from freezing through, stocked with koi or other decorative fish.  They'd appreciate having something more reliable than the klunky windmills or noisy pumps on extension cords.  They don't think of RE solutions (how come nobody does, even after decades of RE ideas in the news?) but this sounds practical enough.

You'll need a weatherproof enclosure, for the buck converter, inverter and the cable connections.
Title: Re: Solar Powered Pond Aerator
Post by: dnix71 on November 25, 2017, 03:16:38 PM

There are lots of self contained solar powered submersible pond pumps out there.

Title: Re: Solar Powered Pond Aerator
Post by: OperaHouse on November 25, 2017, 03:22:20 PM
People use everything including automotive smog pumps. The favorite seems to be these aerator pumps that are designed for septic systems.  They run for years without maintenance and come in a weatherproof case. These ponds can be rather large and may require multiple pumps.  I encourage any solution that doesn't use a battery.  I'm going into production with a board for greenhouse and pond applications acting as a linear current booster.  In searching around I mainly found battery solution till you get into larger three phase pumps. Thumbs up to those, but those are a big solution.  This Missouri solution seemed practical and couldn't find any other place that explained the method.  Search septic aerator pump like 80-hp for examples.

Early on I experienced inverter shutdown with my refrigerator program. I learned you have to a timed shutoff so in the event of a fault the inverter will reset.  The above system would work as well if it had a timer that just shut it off for 10 seconds every fifteen minutes.  Those timers are available.

I see it as an open ended idea.  The question comes up now and then if an inverter can be used with a solar panel without a battery and DC operating equipment is not available.

The load resistor doesn't have to be that big.  Once you get way above the panels voltage power point the power drops off rather quickly with little current.
Title: Re: Solar Powered Pond Aerator
Post by: Mary B on November 26, 2017, 04:47:50 PM
Lots pf 12 and 24 volt air compressor pond pumps here
Title: Re: Solar Powered Pond Aerator
Post by: george65 on November 26, 2017, 05:14:58 PM

One does not need an air pump for aeration.

For many years now I have used a regular water pump to Dry the Veg oil I process for my Vehicle.
The processor is an inverted 44 gallon drum with the 2" bung tapped and going to the pump.  The pump then has 2 outputs, one through a water filter and to clean the oil before returning it to the tank and the other outlet goes through a 1/4" nozzle back into the drum that contains the oil.  The squirter fires the oil stream back into the drum which creates massive aeration, far more than any practical air pump would do. The bubbling takes away the moisture content in the oil ( veg oil is hygroscopic) and leaves the oil Dry.

I got the idea from watching the kids in the pool with the garden hose firing into the water and making bubbles come up like a spa. It definitely works because I can dry my oil to pass test standards in an hour when people spraying or using air pumps and stones can take days, literally.
On a hot, dry day the oil can be completely dry in as little as 20 Min. I have small fan sucking the air out of the drum ( air inlet opposite side) because it gets saturated and the fan has proved critically important. Obviously not needed for a pond application.

I use a 300W pump although I have used much larger but as long as it will fire the oil through the squirter at good pressure, the rest is just unused/ wasted power.
The same sort of thing would work with a pond. Just circulate the water back into itself under some pressure and create the bubbling and it would do a far better job than any air pump. No reason why multiple squirters could not be used spread out a bit as long as the pump had the grunt to drive them.

I can't estimate how much air my setup supplies but a mate had the biggest ( and most exy) air pump for aquariums he could get and it was nothing on the aeration my system provided.  He saw what I was doing and dismayed bought a cheap pump and did the same and saved himself days drying his 1000L batches of Biodiesel.

Just to be clear, this is not spraying the water, it's a concentrated stream back into the liquid that breaks the surface tension and pulls the air down with the liquid being squirted in. I found some of the plastic nozzles I was using made the stream a bit too smooth so an object, preferably a bit rough and jagged, twisted into the nozzle so as to make the outside of the stream a bit rough works best as that tears up the surface tension better and allows for more air to be introduced.

From what I have seen, water pumps are a lot cheaper and easier to get than air pumps.  Oily friends and I have used the cheap QB style Chinese water pumps and they work really well. They are a fraction of the price of brand name pumps so when they finally die, which can take a long time in my experience, you just replace them and don't worry.  If someone feels compelled to by a brand name, they will work every bit as good.

If one had an irrigation pump that was Petrol or Diesel powered, it could do this job as well.
I have seen pumped water being used to aerate ponds and lakes at golf courses and resorts as well.
Title: Re: Solar Powered Pond Aerator
Post by: Bruce S on November 27, 2017, 09:19:31 AM
How big of a pond are you needing to aerate?
That unit that dnix71 posted about may look smallish, but they can do pretty good. I see them around our place, in yards with pools as big as 16 feet dia.

Title: Re: Solar Powered Pond Aerator
Post by: OperaHouse on November 27, 2017, 09:44:08 AM
The ones I see on youtube are lakes! Who knew nature needed life support.  There are also many videos there showing how to connect a solar panel directly to an inverter.  I don't know why people with no idea what they are doing have to share this with everyone.  II just got a 7 lpm micro water pump for the camp hot water system for $15.  Quite impressed with its construction.  I have two tanks and if one tank gets up to temp, I can't get enough dump load with one element.  With this I will be able to circulate hot water to the cooler tank.  Nice pump for a greenhouse, easy to clean.
Title: Re: Solar Powered Pond Aerator
Post by: Bruce S on November 27, 2017, 12:08:34 PM
I like the cute little ones the odd-lot stores sell for about $15USD that have pretty RGB colors  :P
Title: Re: Solar Powered Pond Aerator
Post by: george65 on November 27, 2017, 06:52:19 PM
How big of a pond are you needing to aerate?

I don't have anything to aerate. Just saying what I had done for oil drying and what I had seen elsewhere.

Who knew nature needed life support.

It actually doesn't.
The reason they aerate the ponds and lakes at golf courses and at some nearby housing estates is to keep the water from going stagnant.  Basically keeps the water looking and smelling better. Nature will not care that much if the water is aerated or not, it's the humans that have the hang up. :0)
Mosquitoes would be far happier with still, stagnant water and so would a lot of other plants and insects.

I put a bucket of water out the other day I want to go stagnant to get the mosquito lava/ wrigglers to lay in it.
My gold fish love some live, fresh food but I may have to put some coarse screen over the top to keep the frogs from cleaning them all up!
Title: Re: Solar Powered Pond Aerator
Post by: Mary B on November 27, 2017, 07:13:13 PM
Actually in MN shallow lakes do need mans help to prevent winter fish kill if the ice gets to thick. Several local lakes run aerators to keep a patch ice free so o2 can get in the water.
Title: Re: Solar Powered Pond Aerator
Post by: Bruce S on November 28, 2017, 08:45:18 AM
How big of a pond are you needing to aerate?

I don't have anything to aerate. Just saying what I had done for oil drying and what I had seen elsewhere.

MY BAD, I transposed you with OperaHouse who originally posted the aerator questions

Title: Re: Solar Powered Pond Aerator
Post by: george65 on November 28, 2017, 06:27:43 PM

MY BAD, I transposed you with OperaHouse who originally posted the aerator questions

You probably owe him an apology.
I bet he's insulted at you confusing him for me. 
I think I would be!  :-[


Never know, Mrs and I have been talking about putting a pond in the back yard. I'd dig it myself with the backhoe on the tractor so it was substantial  and just put a liner in.
Having 2nd thoughts though as to it attracting Snakes and other things looking for water. It's pretty dry round here and we have already had a BIG Goanna on the front doorstep last week who was obviously attracted by the garden irrigation. Really don't want any more reptiles, foxes or anything other than birds coming in the place.  The local snakes are the number 2 and 6th most deadly in the world so best not to do anything to make them want to visit.

There is a spot in the back yard that has a " feature" garden atm we both think is a waste of time and eyesore so are thinking of what to do with it. was thinking of a fire pit and surrounds but that would be a very limited use. other option is put in a spa or lap pool. I don't like either of those options because I think the location is wrong.  The pond and making the area " tropical " looking with suitable palms and setout is the favored if unsure option.

Personally, I'd prefer to use the space for another Veggie garden but I know that's just not going to fly with the chief of operations.
Title: Re: Solar Powered Pond Aerator
Post by: Bruce S on November 29, 2017, 07:13:28 AM
I'll type up a formal apology to Operahouse  ;D. I don't want to get cut off from his most informative help with all things Arduino.

We had a nice smallish pond when we lived in Southeastern Michigan, it was a backhoe type pond. 2-3M deep around the edges and 1/2 M in the middle. Had no problems with 2nd or 6th deadliest snakes, but did have snakes around it that would make your day go from bad to worse (who knew they had rattlers up there!)
The beaver and birds were more a problem, that and the sun perch that had teeth; made a cool dip a whole new experience.

Title: Re: Solar Powered Pond Aerator
Post by: OperaHouse on November 30, 2017, 11:42:43 AM
I can assure everyone I am not full of it, just finished a colonoscopy this morning.  I don't have a pond if you don't count the water in the basement. Missouri Wind showed this product in a video with the controller in a screw top box.  Seems they don't want to shock people with hoe little is in it.  Note it is in sealed plastic so no one can copy the design.  Still can't use a respectable size grid tie panel with it. In a couple I will have a version that works on two grid tie panels in series.

On a sad note, my water heating experiment is a dismal failure.  The electronics works, but the panels are propped up on a wall and only gt one hour of clear sun.  The rest of the time the 560W panels can put out  between 6W and 60W.  Not sure if I want to drag those big things on top of the roof where it is a little better.  I never envisioned the site was that bad. Thought 3 hours of full sun was possible
Title: Re: Solar Powered Pond Aerator
Post by: george65 on November 30, 2017, 06:33:30 PM

With respect, you were full of hot air!
They would have pumped it into you and then not let you home till you emitted it. My father had one last year and reckoned he could have blown the candles out on his birthday cake from 30 ft away.
Geez I dread the day when I have to have one of those. I'm very shy about my private bits and the thought of having someone stick something up my nether regions does not sit well.... pun intended.

The Offgrid/ renewable/ solar  industry reminds me of and is exactly the same as the veg  oil Fuel component suppliers that sprang up when that was a craze.  They simply took off the shelf products used by other industries and hyped them as speciality items and put ridiculous mark-ups on them.
There is some development of products as there was with veg components buy by and large..... Ripoff.
I noticed they were selling 3 phase rectifiers for $38..... the very same ones I bought off fleaby some months back for $7.XX ea.... delivered. To me, they want another $30  for postage! Ya!   ::)
Just like the veg game, they WILL sell them to people.  Some won't look anywhere else and some will think that they are " Special" for solar and that fleabay ones won't work.... just like people did with filters, valves and heat exchangers in the veg game. 

First thing I noticed watching the vid is they use a 12 V panel.  This is an example of the industry being self serving to me. Anything 12V I have seen here is ridiculously over priced and under powered compared to the cost of a new, off the shelf roof type panel which will undoubtedly have a far higher output.
Buy the controller but of course you are going to need one of these overpriced, under powered 12V panels with it. Or several to do anything much with them.

I will be very keen to see what you come up with for a setup like this even though I inevitably won't have the skill and knowledge to build it. I may be able to learn something or get the gist of the theory of operation though.
For us mere mortals, it seems an incredibly difficult thing to harness solar generated power into anything more than just battery charging and grid tie when it does not seem it should be. 

I would suggest your water heating is not a failure at all but rather your panel location choice is.  Can you not ground mount the things in a more suitable spot and just run a ( buried?) wire back to the controller?

My test setup is playing havoc on the lawn and has killed off a sizeable area where it's lying flat on the grass.  Where it's raised, the grass is going nuts compared to what's around it. I think having it shaded allows the moisture to be better absorbed and results in better growth. Mower over that and it will be fine... although one hell of a contrast with the thick lush area to the barren brown one!  :0(
 Having some family gatherings coming up and to make the place look less like a junkyard , I thought I'd just put them up on the shed roof for the time being till I finally decide how I'm going to mount them.  I thought they are lying flat on the grass, cant be any worse on the 5 and 13o  pitch of the roof.
" Ideal" tilt here is 34o but I have run the numbers and want to optimise for summer so going to set them up at 25o.

I thought I'd run the numbers again to see how much I'm going to loose at those "flat" roof angles. To my great surprise, I'm going to make more with them from November ( ooops) till march than I would at either 34 or 25o.  Looking this morning, I realise how much more overhead the sun has become in the last couple of months.  There is a lot I have learned with this stuff well beyond the immediate technology itself.

I can now put the panels up there temporarily till I do some more number crunching and get over the silly season and my Daughters up coming 2st Birthday party  before I need worry about mounting the things properly. Might just screw a bracket in them and to the roof bolt hole for good measure against the wind and then I'll have time to mock up some mounting frames for the permanent fixing.

You should feel grateful only looking at hauling 2 panels on your roof. I have 30 of the buggers I want to get up there!
 I have made a ramp out of a couple of 3x4's I have braced together and the idea is to stack them at the end then  lay them on the ramp, have a helper ( there's the wishful thinking part!) attach a hook under the lip with a strap and and then slide them on up.

Wish to hell I had that tractor I want now instead of having to wait a week for the thing! Put them all on a pallet and hike them up.  Need them out the way now as they are annoying me and my anxiety/ OCD/ whatever will drive me nuts no matter how many other things I could kick on with in the mean time... of which there are endless!  :0)
Title: Re: Solar Powered Pond Aerator
Post by: OperaHouse on December 01, 2017, 02:31:54 AM
At camp my panels are almost flat  and that gives me even performance throughout the day much like the 60 degrees east and west positioning.  All I need to survive is a consistent 4A throughout the day since battery storage is minimal.  Flat for a pond would work out well.  The home panels are just a reminder that dreams suddenly hit reality and it is difficult to get a fully unobstructed view.  I just don't see me with solar at home because I want to leave this place and while I am here it is only the winter months with the least solar production.  It just doesn't make sense.  When I had a panel on the roof a few years ago I could get watt hours of 2.5 times the panels watt rating.  In current position this seems to be about one.  The low wattage tracking does work great.