The best way or ways to calculate Pump efficiency

Sleepe

Aside from how much water do I need at the GB's and several other factors in Q1 I would take B.

Q2 I would have to see the pumps in question. B sounds like a semi slinger inlet would be questionable. probably not build up as much crap on the outlet pipe, but would be pissing water out in the GB's with some force.

What I would buy Myles depends on where its going to and what my configuration is at the end and where I'm pulling it from.

mylesau

Sleepe wrote:

Aside from how much water do I need at the GB's and several other factors in Q1 I would take B.

Can I ask why B over A Sleepe? You can assume the amount of water the pumps are delivering is enough for the needs of the growbeds.

Sleepe wrote:

Q2 I would have to see the pumps in question. B sounds like a semi slinger inlet would be questionable. probably not build up as much crap on the outlet pipe, but would be pissing water out in the GB's with some force.

Yes, Pump B shoots water out much further than Pump A (same flow through a smaller outlet). [What's a semi slinger inlet or is that a typo I can't quite un-typo?]

Sleepe wrote:

What I would buy Myles depends on where its going to and what my configuration is at the end and where I'm pulling it from.

Another out of the box answer which I think is valid for the question in the thread title. +1 to Sleepe :cheers:

Sleepe

Aside from the fact I have been sniffing polyurethane paint all afternoon, unintentionally, here goes.

Q1 pump B can handle both GB's with the head and restrictions etc pump A, you don't tell me what it can do at pump B's GB's

I describe impellers as what I see them, slingers for head/pressure, paddles for low/no head flow. Slingers look like disks, hole in the center small impeller exit point, round the periphery. Paddles are self descriptive.

hygicell

Stuart Chignell wrote:

hygicell wrote:

there is no contradiction, there just seems to be because l/w doesn't give you the reference to what 100% efficiency could be
this pump is absolutely outstandingly awful at this head however you look at it, in % or in l/w
the results are the same
frank

Ok well I disagree but what about this one: (viewtopic.php?f=8&t=4661&st=0&sk=t&sd=a&hilit=srac&start=135)

hygicell wrote:

efficiency results:
head in m flow@head flow@head pump rating pressure in bar pressure in mbar pump effect pump efficiency l/w
0.038 m 3107.0 l/min 186420 l/hr 750 watt 0.004 bar 4 mbar 20 watt 2.62% 249 l/w

249L/Whr @ .038m is one of the best results that has been posted but 2.62% efficiency seems really crappy to me.

we already know that @ 0.038 m 100% is equal to 9474 l/w

249 l/w / 9474 l/w = 2.6282 %

the results we reach are the same

249 l/w may not "seem" crappy, it is crappy @ 0.038 m

the same 249 l/w is excellent @ 1.4 m:
1.400 m 270.0 l/min 16200 l/hr 65 watt 0.140 bar 140 mbar 63 watt 96.92% 249 l/w

surely you can see how the l/w expression leads to confusion

but I do not refuse a compromise if you all deem it necessary
I vote for using the calculator and posting the two results (% and l/w) @ head when discussing a pump for an application

frank

mylesau

Sleepe wrote:

Q1 pump B can handle both GB's with the head and restrictions etc pump A, you don't tell me what it can do at pump B's GB's

eh? Pump B is only pumping to the far growbed, if it were to be used for both, the flow would have to be split. Oh, okay I think I get you now. The pumps can only handle the flow to the one GB, not both. Consider them as separate entities - ones mine and ones my neighbours :wink:

So I guess from what you've said it would mean that you can only really compare two pumps operating under the same conditions? [correct me if I didn't get what you said] +1 to Sleepe :cheers:

Sleepe wrote:

I describe impellers as what I see them, slingers for head/pressure, paddles for low/no head flow. Slingers look like disks, hole in the center small impeller exit point, round the periphery. Paddles are self descriptive.

Gotcha. Would that influence your (fume effected) decision for selecting Q2 Pump A or Pump B?

hygicell

mylesau wrote:

I have a quiz that hopefully will help shed some light on this topic (or add more confusion, probably more likely). I know the answers 'cause I created the quiz. There are two questions in this quiz.
Question 1
I have two pumps; Pump A and Pump B.
Pump A pumps straight up and onto a growbed next to the pump. The total head (including fittings etc.) is 1.0 metres. The flow rate has been measured at 2,100 l/h.
Pump B pumps to another growbed some distance away. The pipework has a number of bends etc. but the total head (including fittings etc.) is 1.5 metres. The flow rate has been measured at 1,700 l/h.
Both pumps require exactly 35 Watts of power to run.
Which pump would you buy?

1.000 m 35.0 l/min 2100 l/hr 35 watt 0.100 bar 100 mbar 6 watt 16.67% 60 l/w
1.500 m 28.5 l/min 1710 l/hr 35 watt 0.150 bar 150 mbar 7 watt 20.36% 49 l/w
this is an excellent pump, Myles

Quote:

Question 2
Again I have two pumps to choose from. This time they are both pumping to the same growbed. So both pumps are pumping to the same head height.
Pump A has a large discharge outlet so 40mm PVC pipe is used. The total head (including fittings etc.) is 1.0 metres. The flow rate has been measured at 2,100 l/h. Pump A requires 35 Watts of power to run. [Yes this is the same pump as Pump A in Question 1]
Pump B has an unusually small discharge outlet (because of the type of pump that it is) so 20mm PVC pipe is used. Due to the smaller pipe used, the total head is higher as more friction is created. The total head (including fittings etc.) is 1.2 metres. The flow rate has been measured at 2,100 l/h. Pump B requires 40 Watts of power to run.
Which pump would you buy?

1.000 m 35.0 l/min 2100 l/hr 35 watt 0.100 bar 100 mbar 6 watt 16.67% 60 l/w
1.200 m 35.0 l/min 2100 l/hr 40 watt 0.120 bar 120 mbar 7 watt 17.50% 53 l/w

frank

Dufflight

What color are the pumps. Cos they have to match my gb's. :mrgreen:

mylesau

Which one would you buy for Q1 and Q2 Frank?

mylesau

Dufflight wrote:

What color are the pumps. Cos they have to match my gb's. :mrgreen:

You know Duff, I new someone would ask this question, and I guessed it might be you :mrgreen:

The two pumps in Q1 are both black.

Pump A in Q2 is black, and Pump B in Q2 is blue. No you don't get a point for that question Duff :lol:

RupertofOZ

I peeked at the paper you wrote the questions from.... so I know that Pump A is a circular pump 20cm diameter.... and Pump B is a square pump measuring 20cm x 20cm...

Therefore I'd choose Pump B.... coz someone told me that it would take up less room... even though I argued with them.... :wink:

Do I get a point??? ..... did I get the point??? .... :wink:

Dufflight

Q1 I'll take B. Cos it sounds like my system. Too many bends and the pump is never close enough to the the GB's.

Q2 I'll take the blue one. Cos they match my eyes. Well my eyes are green but my black pump ended up that color anyway. :compress:

mylesau

RupertofOZ wrote:

I peeked at the paper you wrote the questions from.... so I know that Pump A is a circular pump 20cm diameter.... and Pump B is a square pump measuring 20cm x 20cm...

Watch it, you'll get 0 for cheating :twisted:

RupertofOZ wrote:

Therefore I'd choose Pump B.... coz someone told me that it would take up less room... even though I argued with them.... :wink:

But for which question Rup? Pump B in Q1 ain't the same as Pump B in Q2.

:study:

Okay, you get half a point - the pump must fit! (Always some smart arse in the class trying to get extra credit) +1/2 for Rup :hmm:

mylesau

I refuse to give 1/4 marks Duff - and you'd only get that if I added up all your attempts. :snooty:

Food&Fish

Yes but every body knows round corners gives a better water flow :lol:

RupertofOZ

mylesau wrote:

Okay, you get half a point - the pump must fit! (Always some smart arse in the class trying to get extra credit) +1/2 for Rup :hmm:

.... lost 1/2 a mark because I forgot to say .... "therefore it makes more efficient use of the space" .....

:banghead:

... forgot the whole point of the argument.... :banghead:

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The best way or ways to calculate Pump efficiency

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