Backyard Aquaponics
A place to discuss aquaponics

Hi everyone,

What is the fraction of pumping capacity used to operate a pump at max (energy) efficiency?

Assumptions: Continuous flow system, media bed, inline pump, volume of bed and rate of pumping is known.

To rephrase my question, hypothetically, if I had to pump 100 gal/hr of water (in a tank) up 4 feet, what size/power pump should I get?

Thanks!

The pump should have a chart that tells you how much water it will pump at various head (height).

Are you sure that the chart lists those pumping rates for max efficiency? I assumed those only told the pumping abilities.

I meant to say what size/power pump should I get for the best energy efficiency

I also meant to say submersible pump, NOT INLINE (oops)

Let me start by saying that i dont know.

But it seems like when i raise the height on my pump, it just pumps less water. I ASSUME it uses the same amount of power.

I guess if i dropped my output below the input i could create a siphon and use the pump motor as a generator, which would be super efficient until i melted something or started a fire.

Correct, you will get less flow at higher heads



Incorrect, as you restrict the flow, or increase the head, power consumption usually decreases a bit.




very incorrect!

So gunagulla: for the op, is it possible to know or calculate power consumption at different flow rates for a given pump? How much does restricting the flow impact power consumption?

Not for the end user, the only way is to measure it, and some manufacturers provide curves showing flow head height and power use vs flow. You can work out the efficiency at the various pumping rates/head heights from those 2 curves, and some manufacturers even give efficiency curves as well.

Restricting the flow is exactly the same as raising the outlet pipe as far as the pump is concerned- it shows as an increase in pressure at the pump outlet. Blocking the flow completely is the same as raising the outlet until there is zero flow, at which point the pump is 0% efficient, it's just churning water around the impeller housing. All the power is just being dissipated as frictional heating and noise, but power use will be less than when it is pumping a significant quantity of water.