Need guidance on solar application for drip irrigation

missinpa

Hello, I am new to the forum so I apologize if some of the same issues have already been addressed. Wondering if anyone can help in this scenario?

Myself and a few other church members are knee deep in the first year of a
community garden. We have patterned our garden off of another church
garden in terms of size, plants grown, etc. I was a late-comer to the
group, so I did not have the pleasure of touring the other church garden.
I do know they have a water tank and they were using drip irrigation.

We too, have installed drip irrigation and just recently purchased a 3000
gallon tank. It is 8' in diameter and 8' tall. The drip irrigation
requires 4-7 psi to work properly, so we have done the calculations to
determine that our tank would need to be 8' in the air to have adequate
pressure. This is unrealistic on so many levels and so we are exploring
the possibility of pumping the water out of our tank.

Our tank will be placed no more than 30 feet away from the actual garden.
The tank currently has a port that we were considering hooking our gravity
flow irrigation to. The port is probably 18 inches from the bottom of the
tank. We have a 1" header line feeding to 3/4" drip line. The overall
garden lays on a gentle slope, and we will be placing our tank at the top
of the slope. Garden size is 75' X 100'.

I find myself spending hours on the internet trying to find information on
this subject. Being a church, we do not have a big budget and would like
to do this as economically as possible. We are considering solar.

Can you guide us in the right direction as far as what kind of pump we
should be looking for and how to make this a solar application? Is a
surface or submersible pump the best for our scenario? Any other advice
you can provide would be immensely appreciated!

Thanks in advance,

Missy

Cariboocoot

Re: Need guidance on solar application for drip irrigation

Welcome to the forum.

Chances are very good that solar will not be the inexpensive option. Where there is grid there is cheap power.

Getting a 120 VAC pump that can supply 7 psi at a low flow rate should not be too difficult.

One of our members has such a system for his commercial agricultural operation. I hope he will chime in here with some recommendations.

BB.

Re: Need guidance on solar application for drip irrigation

Since your irrigation is during the day--You should also be able to use just a pure DC pump+solar panel, plus you may possibly want/need an LCB (Linear Current Booster).

7 amp Linear Current Booster/Pump Driver

Used to control and power a DC motor from a solar panel. The unit prevents stalling of the motor under less than full sun condition. The power of the sun is transformed to the motor running conditions so as the sun goes down the motor slows down instead of stalling. Conversely, or as the sun comes up the motor starts running much earlier instead of staying stalled for hours when it could be running. This translates into more running time of the motor where it spends a lot of time working instead of stalled doing no work. This unit is suitable for such pumps as the Shurflo 8000 and 2088 series, where you do not need all the features and capacity of a full blown heavy duty pump driver. 1 year warranty

But, if you can at all bury an AC power line from the church to the tank--It will probably result in a cheaper/more reliable system.

-Bill

missinpa

Re: Need guidance on solar application for drip irrigation

I'm not sure we would irrigate during the day. All of our volunteers have day jobs.

If we are unable to convince the church to let us run an electric outlet to the garden, can you make a suggestion for a solar solution? And if you wouldn't be opposed, I know almost nothing about solar and how it all works. Would you mind explaining the basics and the equipment necessary?

Thanks so much,
Missy

Cariboocoot

Re: Need guidance on solar application for drip irrigation

missinpa wrote: »

I'm not sure we would irrigate during the day. All of our volunteers have day jobs.

If we are unable to convince the church to let us run an electric outlet to the garden, can you make a suggestion for a solar solution? And if you wouldn't be opposed, I know almost nothing about solar and how it all works. Would you mind explaining the basics and the equipment necessary?

Thanks so much,
Missy

Not at all.

In this case you are looking at an off-grid system, meaning the utility is not involved.
Basically you have batteries that run the loads. These may be DC direct loads (most efficient) or AC loads powered through an inverter.
The batteries are recharged during daylight hours by the solar panels, charging being regulated by a charge controller.

I personally have found that water at night works better as less water is evaporated into the air by the sun.

So first we need to find a pump that suits your purposes, then determine how to get the power to run the pump. I have no experience with drip irrigation systems so I can't help pick a pump. Power systems on the other hand I have got some experience with.

jonr

Re: Need guidance on solar application for drip irrigation

I have a solar powered drip irrigation system and it pumps at 20x higher pressure than that. So you need 4 psi/9 feet of pressure. How many gallons per day you want to pump out of the tank?

Avoid batteries - pumping for drip irrigation only when the sun shines is fine.

Cariboocoot

Re: Need guidance on solar application for drip irrigation

jonr wrote: »

I have a solar powered drip irrigation system and it pumps at 20x higher pressure than that. So you need 4 psi/9 feet of pressure. How many gallons per day you want to pump out of the tank?

Avoid batteries - pumping for drip irrigation only when the sun shines is fine.

There is no need to avoid batteries.
If you want irrigation when the sun doesn't shine they are necessary.
Otherwise you need to set the system up so that it can run the pump consistently direct from panels.

mike95490

Re: Need guidance on solar application for drip irrigation

First, calculate how much water you will consume on a daily basis.

You are going to be using a fine (#200 ) filter before the drip system or planning to replace clogged drippers each month.

park a 30 gallon tank on top of your main water tank, and pump water to it, and let gravity run the drippers. For 8' lift & 30 gallons, you can use a manual bilge pump.

And I have about 1.5 miles of drip line watering 300 trees daily. Been through a lot of drip stuff.