Outdoor Wood Furnace Info

All-Purpose OWF Discussions => Plumbing => Topic started by: Coyote556 on February 17, 2014, 09:42:55 AM

Title: Pump power consumption question.
Post by: Coyote556 on February 17, 2014, 09:42:55 AM
How much power can I figure on the two pumps consuming?  I will need two pumps because I will be running two different structures.  It seems like pumping water 24/7 would consume lots of power.  I will have one 150' run and one 80' run.  Thanks
Title: Re: Pump power consumption question.
Post by: Sprinter on February 17, 2014, 04:25:51 PM
Well if its designed correctly to flow 2ft/sec they don't use much at all. 36 watts moves 16 GPM. Or I've seen 400 plus watts only move 4gpm.
Title: Re: Pump power consumption question.
Post by: Coyote556 on February 17, 2014, 05:21:32 PM
So the key to keeping the power consumption down is correct sizing?
Title: Re: Pump power consumption question.
Post by: slimjim on February 17, 2014, 06:27:07 PM
Design is very important, as little restriction as possible is best, typically the circs we use are .75-1.5 amps.
Title: Re: Pump power consumption question.
Post by: willieG on February 17, 2014, 08:41:21 PM
Design is very important, as little restriction as possible is best, typically the circs we use are .75-1.5 amps.

half way inbetween....1 amp
1 amp x voltage divided by 1000 x the number of hours it will run in a day

1 amp x 110 = 110 / 1000 = .11 KW per hour x 24 hours = 2.64 KWH per day x cost of KWH (in my case 21 cents per KWH) = 55.44 cents per day
Title: Re: Pump power consumption question.
Post by: Coyote556 on February 17, 2014, 09:54:28 PM
Thanks Willie
Title: Re: Pump power consumption question.
Post by: slimjim on February 18, 2014, 05:02:26 AM
Thanks Willie, now my head hurts!
Title: Re: Pump power consumption question.
Post by: LittleJohn on February 18, 2014, 10:40:46 AM
Pump size makes a huge difference also; for comparison pulled numbers for a Grundfos Alpha (15-55) & Grundfos 26-99

Alpha max load - .65 Amps
26-99 max load - 2.15 Amps

There is a large differnce in the amp draw, but if you look at their respective pump curves the 26-99 has almost twice the capacity head pressure and GPM

NOTE: General rule of thumb is to figure out required GPM and head pressure and try to run a pump and speed where this is satified by the middle third of the pump curve.  This prevents over pumping or excessive head pressure
Title: Re: Pump power consumption question.
Post by: Coyote556 on February 18, 2014, 11:42:12 AM
Do you figure out GPM and head by the pipe size and run length and the rise to the HX from the pump?  How do you know if you should run 1" or 1.25" underground pipe?
Title: Re: Pump power consumption question.
Post by: Coyote556 on February 18, 2014, 05:53:48 PM
Willie, I sent you a msg back.  thanks
Title: Re: Pump power consumption question.
Post by: Sprinter on February 19, 2014, 07:55:29 AM
Do you figure out GPM and head by the pipe size and run length and the rise to the HX from the pump?  How do you know if you should run 1" or 1.25" underground pipe?

Go and watch the Taco flo pro university videos. All info you will ever need is there for sizing, design and calculating.

Circulators do not see static pressure only dynamic head. (Friction loss).  What goes up must come down, thus canceling any static head that might exist. Every 28" in elevation is 1psi. You won't ever find static head on a pump curve chart for a reason.
Title: Re: Pump power consumption question.
Post by: LittleJohn on February 19, 2014, 09:03:48 AM
Sprinter, Would you not have to account for static pressure if you have an open system, otherwise how can you guarentee that the pump will operate as required
Title: Re: Pump power consumption question.
Post by: Sprinter on February 19, 2014, 09:13:20 PM
Sprinter, Would you not have to account for static pressure if you have an open system, otherwise how can you guarentee that the pump will operate as required

Nope, never.....what goes up ,,,,,,,,,must come down. On an open loop, 100 feet uphill and 100 feet on the return down the same hill back. They cancel each other out. Watch videos......explains much better than I can type. They are very short and simple, so even I can understand them.