Inline Booster Irrigation Pump

[khodge]

I'm planning an off grid, stand alone pasture irrigation system. I currently have a connection to a gravity fed irrigation connection that provides 23psi and 80gpm at the gate valve. I am wanting to install a inline booster pump that is solar powered and can give me a psi boost from 23 to 50psi and still continue to allow around 50gpm of flow. I will be lifting the water roughly 30ft elevation gain to my sprinkler head. All of the components will be outdoors during my irrigation season of May through September, so I would like the components to be outdoor rated if possible. Ideally I would have no battery backup and just run the system during daylight hours. I am in Western Montana, so during my irrigation season I have 12+ hours of daylight each day. Any advice to this newbie will be much appreciated. Thanks!

 

[OzSolar]

I'm planning an off grid, stand alone pasture irrigation system. I currently have a connection to a gravity fed irrigation connection that provides 23psi and 80gpm at the gate valve. I am wanting to install a inline booster pump that is solar powered and can give me a psi boost from 23 to 50psi and still continue to allow around 50gpm of flow. I will be lifting the water roughly 30ft elevation gain to my sprinkler head. All of the components will be outdoors during my irrigation season of May through September, so I would like the components to be outdoor rated if possible. Ideally I would have no battery backup and just run the system during daylight hours. I am in Western Montana, so during my irrigation season I have 12+ hours of daylight each day. Any advice to this newbie will be much appreciated. Thanks!

That's quite the application! Welcome to the forum!

You'll need to calculate the the TDH. Total Dynamic Head, which will include the lift, the pressure you want to have at the outlet and the total friction loss of all the piping between the pump and outlet. From there you can start to zero in on pump selection.

FWIW: You'll only get about ~5 to 7 hours of full rate pumping from a solar direct pump in the summer. EG: A 50 GPM pump wont hit 50 GPM until ~10AM and start to taper off after 3 PM so you need to size for total daily need vs. GPM. You can overcome this to a degree by increasing the size of your solar array and/or adding a tracker but even then you probably won't get to 12 hours of full rated flow plus trackers love to break pointing the wrong direction.

 

[khodge]

Thanks! That works out to about 9/10th of an inch of rain if I'm able to run a zone for 6 hours. Timothy grass only needs about an inch per week to get a second bailing.

Anyone have experience with the Grundfos CR Flex? Their website says I should get the CRF 10-2 any power it with 4) 390w solar panels in order to exceed the flow and pressure that I'm needing in July.

 

[OzSolar]

No experience with the CR Flex but a fair amount with the SQ Flex. I've got some still going strong after 20 years.