what is the ideal flow rate per tub?

[DeRail]

I have been reading a lot on these MPBs what is the ideal flow rate per 27 gal tub? my thought is using one large pump.


And using Flow meters and valves



It would use less power and create less heat since the pump would be out of the room with the chiller. I could run a 1 1/2 pvc manifold and control the drip,feed and chiller with one pump I am a certified instrumentation technician I know i can make this work I just need some flow rates for the tubs and drippers what head pressure is Doubleds running has static pressure been accounted for?

 

[mcattak]

I have about 500 - 600 gph running through each tub...


mc

 

[Papa]

DeRail, i was once thinking the same way about building a manifold and running the drip, feed and chiller from one pump . . . the more experienced fellas advised me against this and recommended running separate pumps. they said that in the end it is much easier to control flows if they are entirely isolated on different pumps.





Papa

 

[DeRail]

Papa,
If you are running a good efficiency pump there should be no problem whole factories and refineries run like this all day long. this is where the flow meters come in and instrumentation and calibration experience will come in handy The flow meters don't lie (unless they are out of calibration) you can set any flow rate you want and it will stay the same.
the Reeflo/Sequence hammerhead Gold Pump 4700 GPH is very efficient and will not transfer heat to your liquid and has plenty of pressure and will not heat up when throttled down to slow flow like other pumps.
This way might cost a few more dollars in the beginning but you will have better control and use a lot less power and generate less heat.

 

[DeRail]

1-1/2 inch pipe for up to 1800 gph
2 inch pipe for up to 3600 gph.

More complicated way is to iteratively estimate the total head, which
is the sum of static head plus dynamic head.

Here's a table of dynamic head (pipe friction back pressure):
website below no longer active


2400 gph through 70 feet of 1-1/2 inch pipe = 6 foot dynamic head.
2400 gph though 3 feet of 1 inch hose = 2.4 foot dynamic head
Total head = 3 + 2.4 + 6 = 11.4 feet.

Now refer to the performance table on the pump's box. Guess the
flow rate at 11 foot head would be 1200 gph. Use that for the next
iteration.
1200 gph, 70' 1.5" pipe = 2 foot head
1200 gph, 3' 1" hose = 1 foot head
Total head = 3 + 2 + 1 = 6 feet.

Again referring to the pump's table, 1700 gph at 6 feet.
1700 gph, 70' 1.5" pipe = 4 foot
1700 gph, 3' 1" hose = 1 foot
Total head = 8 feet.

Pump table: 1500 gph at 8 feet.
1500 gph, 70' 1.5" pipe = 2.8 feet
1500 gph, 3' 1" hose = 1 foot
Total head = 7 feet.

Pump table: 1600 gph at 7 feet.
Iterate again, we'd get 1550 gph. Close enough.

If you go to 2 inch pipe, head will be 3 feet less, flow will increase
by about 300 gph. If you get rid of the 1 inch hose, head will be 1 foot
less, flow will increase by about 100 gph. Both together, 2 inch pipe,
dynamic head would be 1.5 foot, total head 4.5 feet, flow 1850 gph.
That's a 15 to 20 percent increase in flow. Not clear if it's worth it;
depends on how much trouble it'd be to replace the pipe.

For all these Danner pumps, as head increases, both water flow
and electric power drawn decrease. The Danner 2400 gph pump has 1 inch
fittings. I think these act as nozzles to limit the maximum flow if no
plumbing were attached. This keeps a load on the motor, limiting the
maximum electric current and heat the motor must dissipate. That's just a
guess, though.

 

[noone88]

I aim for 400-500gph per tub.

A manifold system works, but what i've found better is to use pvc pipe the whole way and use pvc stopcocks to control the flow.

You can try to use one pump to control the drippers, cooler, and the tubs, but I don't think you're really "saving" anything in terms of electricity or cost. You'll be almost forced to use a non-submersible pool pump with high flow rates (which easily pull about 300 watts if it's 5000gph+).

It's a project you can definitely do, but ultimately, I'm not sure if the effort will be worth it.

 

[Purkle]

Plus if something bad happens and that pump shuts off then you might wish you still had your seperate pump on the drip or main feeds. The air stone might save ya. All eggs in one pump might end scrambled.