hydro powering our tanks

[phish guy]

i was just thinking the other day, why dont we incorperate hydro power generators into tanks, ecspecially larger systems. i mean with all the water flow we encorperate through filters, isnt there a way to harness the power? just simple wheel on the inlet would spin like a turbine in a dam and generate power.

now im no electrican but wouldnt it work? i mean i dont think we could power our houses or anything but couldnt it at least power our tanks, or at least cut the cost of powering our tanks?

just some thoughts. anyone think it would work?

 

[ahoyhoy239]

you wouldnt be able to have the tank power itself but you could probably power like a fuge light and small things like that, so yes it would work to some extent

 

[iCam]

I might just put a dam in mine.

 

[mscarpena]

I was thinking of trying to build some small turbines to power my house with wind power. It can not be that hard right??

 

[greenbean36191]

There is no free lunch. You could install a turbine and get energy back from it, but there's no such thing as 100% efficiency. You would be taking electrical energy, converting it to mechanical, then back to electrical (and then presumably either to mechanical or light) with losses at each step. You get back a lot less energy than you put in. The turbine would decrease the flow, so in order to get the same amount of flow you originally had, you would have to increase the wattage of the pump by more than the wattage put out by the turbine. If the lower flow doesn't bother you then it would still cost less to just run a smaller pump than it would to run the current pump, with the energy reclaimed by a turbine.

 

[samtheman]

Are physics classes still required in High School?

 

[TheFishGuyLLC]

Nope, and they've made college physics easier.

 

[old salty]

This is also being touted as "Progress".

 

[ozyreefa]

Quote
The turbine would decrease the flow, so in order to get the same amount of flow you originally had, you would have to increase the wattage of the pump by more than the wattage put out by the turbine.


This is not entirely correct. Putting a turbine into, say, the pipe that heads towards the sump in a bulkhead overflow setup, will not require a bigger pump, but a larger over flow. There is absolutlely no resistance put on the return pump by putting anything into the overflow (unless your entire display and sump are completely airtight, which of course, they are not), however it will take more water above your overflow level to balance out resistance in the pipe from the turbine( higher water level means increased pressure into the overflow pipe itself).

 

[kaptken]

Well GB, there certainly is no free lunch when energy recovery is concerned, but there is subsidized. We could recoup some of the energy expended in raising water from sump to tank and falling back again. It seems to me we did a thread like this a couple years back on the large reef tank forum?

Regular, sealed tight clearance turbines would be a very bad choice for many reasons. First they need a lot of flow with a very large head of water and no bypass. that would be bad when the impeller shaft gunks up with calcium and holds up the impeller. back up and overflow the tank.

My best suggestion would be to build a 3 foot diameter acrylic bucket wheel, like an old colonial overflow gris mill water wheel, supplied by the tank overflow return to the sump. enclose it in a gasketed acrylic box with lots of room for the water to overflow should its shaft get impacted with calcite. the large diameter wheel would provide low speed torque to drive an external pulley and belt system geared to turn a DC generator. and preclude tank overflows. The DC power could be conditioned with an inverter to run a pump or powerhead. or heater. recapturing some of the spent watts by gravity.

But a much simpler app would be to install a few 1 1/2 volt solar cells in the light hood to collect reflected light, and run the hood DC computer type exhaust fans. Lights on... fans on.. no need for extra power cord, transformer, and timer.

 

[ozyreefa]

Quote
"But a much simpler app would be to install a few 1 1/2 volt solar cells in the light hood to collect reflected light, and run the hood DC computer type exhaust fans. Lights on... fans on.. no need for extra power cord, transformer, and timer."



This is such a ridiculously good idea that I cannot believe hood manufacturers havent already incorporated this design already, you take a look at almost any lighting fixture and i think it is fair to say that at bare minimum at least 10% of the light never reaches the tank, in some metal halide fixtures in can be much more than that though, so I think almost any tank is capable of reusing its dead loss of power. Im off to the electronics store to pick up some fans and solar panels, and im going to pick up a cheap dyno and have a play around with a few ideas towards hydro powered tanks. Should be some interesting results.

 

[samtheman]

You will be wasting your money. But, your education will be useful to others, so post your results.

 

[ozyreefa]

lol yeah i dont even need to cool my tank, it sits at 24.5C year round. Im just keen to see how much power can be generated from wasted light and falling water, i expect more power to come from the lights though!

 

[chrissreef]

there's a lot of ridiculously good ideas... the problem is they cost $ and "effort" that the opportunity cost of just screwing in a light bulb and burning electricity using old technologies outweigh the benefits to short term thinkers.

I believe there's a solar company out there that installs cells on peoples homes for free and either pays them for the electricity, or locks in their rate so it never ever increases - if there's extra power, they put it into the grid and sell it to other electricity providers. It's a great idea that's spreading slowly.

Another idea - which I really don't understand why everyone doesn't do this... is just install 1-2 small wind turbines on each home. They wont' power the home (like ovens, refridgerators, washers/dryers, aquariums) - but they'll certainly provide for LED/CF bulbs and small appliances like DVD players, cable boxes etc.

 

[simmons797]

<a href=showthread.php?s=&postid=11556441#post11556441 target=_blank>Originally posted</a> by ozyreefa
There is absolutlely no resistance put on the return pump by putting anything into the overflow , however it will take more water above your overflow level to balance out resistance in the pipe from the turbine

This sentence is a contradiction. How do you get more water above the overflow? By the pump pushing the water to higher level=more pressure head=pump working harder to produce the same flow (or bigger pump)=more electricity.

As an earlier posted put it "there is no free lunch".

 

[ozyreefa]

I dont know where people are going wrong with this, if you have a bulkhead over flow, put something over it to partially block it, you will notice the water level in the sump drops a little and the level of water in the tank raises a little. Thats it.The only way it would create more head pressure is if you needed to make the return pipe taller, which you will not. I suppose alot has to do with where your return pipe enters the tank, but for the majority of us who have the return just below the surface of the water, the increase in head pressure would be fractional, particularly with returns that loop over the top of the tank.

 

[samtheman]

Well, when do we see some actual trials?

 

[simmons797]

I don't want to start an argument but there flaws in your statement.

<a href=showthread.php?s=&postid=11564373#post11564373 target=_blank>Originally posted</a> by ozyreefa
I dont know where people are going wrong with this, if you have a bulkhead over flow, put something over it to partially block it, you will notice the water level in the sump drops a little and the level of water in the tank raises a little.

Again, what causes the level in the tank to rise? An increase in pressure from the pump.

<a href=showthread.php?s=&postid=11564373#post11564373 target=_blank>Originally posted</a> by ozyreefa
Thats it.The only way it would create more head pressure is if you needed to make the return pipe taller, which you will not.

Not true. The height of the return pipe is not the height you need to measure. The distance from the pump to where the water overflows is the distance relating to the pressure head. You have to think of the tank space between the pump outlet and the overflow as part of the "return pipe", otherwise you could just plumb your return through the bottom of the tank.

<a href=showthread.php?s=&postid=11564373#post11564373 target=_blank>Originally posted</a> by ozyreefa
I suppose alot has to do with where your return pipe enters the tank, but for the majority of us who have the return just below the surface of the water,

You are correct it does matter where the return pipe enters but only in relation to where the overflow is. If your return pipe is above the overflow then it would not matter if the surface level rose (as long as it was still below the return), but you would already be using more energy to raise the water above the point where it is overflowing.

<a href=showthread.php?s=&postid=11564373#post11564373 target=_blank>Originally posted</a> by ozyreefa
the increase in head pressure would be fractional, particularly with returns that loop over the top of the tank.

You are also corret that the increase would probably be fractional,
but any energy recovered would be an even smaller fraction. Thereby using more energy which is the exact opposite of what the original point of this thread was.

 

[kaptken]

no, the water wheel wont back up the overflow. the open overflow falls to an open tray above the bucket wheel, fills the buckets as gravity does its work and pulls it down, rotating the wheel, then dumping it to an open bottom drain to the sump. zero back pressure. its an overshot water wheel. not a turbine that needs pressure and flow.
something midevil, like this
http://www.waterhistory.org/histories/waterwheels/waterwheel2.jpg
or this is better.
http://en.wikipedia.org/wiki/Image:Overshot_water_wheel_schematic.svg

simple , smooth, very efficient.

 

[samtheman]

You say very efficient. What do you mean? If this type of water wheel was efficient, it would be used in dams and other hydro generation. What type of generator are you going to run? You need 120 volt at 60 cycles.