Backyard Aquaponics
A place to discuss aquaponics

Never liked the percentage part. It's to open to manipulation. If you don't like the result just change what it is compared to.

What the? The data in the graphs is shown as the efficiency of the pump - no losses for the motor/drive are included in the values - these are measured values recorded in a database? Values are deliberately measured around only the pump so any influence from the selection of motor/drive is NOT included.

I just read most of this thread and I think you guys are missing the true way these things work. You are mixing apples and oranges and getting watermelon juice. Each half of the pumps you are talking about are completely separate units connected together. Each unit needs to be measured and calculated separately.

You must calculate the motor separate from the pump. Amount of electricity required to operate the motor at it's rated load level at the correct RPM. The difference between the calculated output and the actual output is the efficiency of the motor.

Same with the pump. It should be calculated separately. Amount of power to get the rated flow out at the various head levels. The difference is the efficiency of the pump.

What you are talking about is manufacturers spec sheets on the combination of units. Simply use there spec sheet for the rated flow and their amp rating. Only use the amps and flow rate. If you can measure the actual rates then you can prove the correctness of their charts.

Since that is not what you are talking about all you are concerned with is liters per hour of water moved at the cost of how many watts. Liters per watt. less is better right?

Ok lets see some peoples pumps specs listed with just pump head, liters per hour, and watts.

A secondary issue is how long does that pump tend to run before failure? cost of replacement need to be considered? Yearly cost estimate is the intended result right?

I want to know too........

You are right but from memory that's how I started the thread. If frank were still around then this thread would have kicked off again with the renewed discussion of airlifts.

The confusion arise s from comparing what's theoretically posible (physics) with what is practically needed and is achievable (engineering).

In ap we need flow so airlifts could be the best pumps if low head designs can be developed. Howvever, since air lifts don't develop much pressure and pressure is one of the main components of "work" so they appear to be inefficient especially from a purely physics point of view. Even though they are productive and very efficient from our point of view.