Pumping into storage tank

Discussion in 'Open Loop' started by farmerjohn, May 15, 2018.

  1. farmerjohn

    farmerjohn New Member

    Hello all,

    I am thinking of ways to improve the efficiency of an open loop pump and dump system

    What I am thinking is to find a pump that can fill up a 200 gallon tank as fast as possible with the greatest motor + pump efficiency. Then allow the heat pump to feed off that tank

    So if the tank is 200 gallons and the pump runs at 30 gallons per minute it would fill the tank in 6.6 minutes

    Say the heatpump needs 10 gpm to operate.. that tank would last for 20 mins before it starts to refill again

    My well is 80' down.. trying to find a pump to match what the heat pump needs is very hard

    But say this 30 gallon per minute pump uses 1200 watts

    60 mins / 20 mins = 3 cycles
    3 X 6.6 pump minutes = 19.8 mins

    1200 / 60 = 20
    20 * 19.8 = 396 / 1000 = 0.396 Kwh

    It would be approx the same as running a 400 watt pump at 10 gpm

    My premise is to find a pump / GPM ratio that is most efficient and buffer it with a temp storage tank

    What do you think of my math / idea?


  2. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    Math-wise, you are basing the two pumps being able to more closely match the demands of your system vs. one pump that doesn't quite fit and has an inefficiency penalty for that. This really is specific to your exact needs.

    Plumbing-wise you have more moving parts your system is dependent on.
  3. farmerjohn

    farmerjohn New Member

    My main focus is energy efficiency since I am off grid

    My current pump uses 760 watts at 10 GPM

    With my above math I save 300 watts.. which does not seem like much but on a day where the heat pump needs to run for a long time it could save me over 8 Kwh per day

    Every little Kwh helps!

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