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Critique of Rain Barrel Pump Idea

Rob Meyer


Joined: Nov 14, 2011
Posts: 103
Hey all,

I was hoping I could get a critique of this possible rain barrel pump system. The rain barrel system itself is already constructed, but because I didn't have the materials and was lazy, they're basically on the ground, only raised up about half a foot on concrete blocks for stability, and so they have very little water pressure in and of themselves. I'm hoping that once all 6 barrels fill with the 330 gallons, that will generate a significant amount of water, but once it gets low, I'm afraid that it won't have sufficient pressure to be useful. My first question is whether this assumption is true or false, and as such if I am wasting my time trying to design this pump system. I could wait and see, but it hasn't rained a whole lot here yet, so they're only very minimally filled at the moment.

My second question is whether what I currently have in mind would work. Like I said, the rain barrel system is already built, and so would prefer not to make any major additions to it's overall architecture, such as cutting holes for the insertion of a submersible pump. I'd rather have an external pump system. Here's what I had in mind:



Will this work? The way I see it working is on demand, where I turn the spigot on and activate the pump, and water as needed, and also as a timed system, where both the pump and the rain barrel outlet will be on coordinated timers, allowing for regular daily soaker hose irrigation. Right now when I turn on the faucet, it's just a trickle, not enough to power a hose by any means, but I'm wondering if the outlet was submerged underwater, and was in a bucket with a constant water level that was being siphoned out by the submersible pump, would this be enough pressure to siphon the water from out of the system and maintain a constant water level in the pump bucket? This idea should work in theory, correct? Or am I missing something critical that will cause this system to not function properly?

Any tips, critiques, or better ideas in general would be much obliged.
Ken Peavey
steward

Joined: Dec 21, 2009
Posts: 2338
Location: FL
    
  68
Water pressure is a factor of the height of the water column rather than the quantity of water. For drip irrigation you only need 25 PSI. That half a foot would be enough to operate drip irrigation. If you can raise up your barrels by another block, you'll have all the pressure you need. Caveat: the drip points must be lower than the top of the water level.

There are automatic water flow valves on the market that are designed for inline use. Figure 40 bucks. Rather than include the pump/bucket in your design, if you put an automatic valve coming out of the plumbing from your tanks, you'd be done. Standard hose fittings on the in and out allow you to put them wherever you like. When it comes on, water would flow from the tank to the drip lines, no pump needed. These run on batteries.

here's one for $35.99


Seed the Mind, Harvest Ideas.
http://farmwhisperer.com
Ken Peavey
steward

Joined: Dec 21, 2009
Posts: 2338
Location: FL
    
  68
I've used such a valve. The source was an outdoor water spigot. City pressure was 55PSI so I had to get a pressure reducer valve. It was just a few bucks. At a certain time it would come on, let the water through to the drip lines for 2 hours, then turn off. Ran it every other day.

If you really wanted to do this on the cheap, you could skip the automatic unit, turn it on/off yourself. The water would have to be above the drip points. You may need a pressure reducing valve.
duane hennon
volunteer

Joined: Sep 23, 2010
Posts: 397
Location: western pennsylvania zone 5/a
    
  13


hi rob,

i have a rainbarrel system similiar (on the ground) mine are opened top and i use buckets
i see a problem with you system in matching the flow from the barrel to the pump
if too much flow from the barrel, your bucket will overflow
a tall pump well the height of the barrels would work (a pipe big enough to fit the pump into)
connect the barrel drains to the bottom of the pump well.
the water in the well will be the same height as the water in the barrel


Rob Meyer


Joined: Nov 14, 2011
Posts: 103
Hm, so pressure is dependent on the water level, not the actual height of the barrels or quantity of water? The spot that the barrels are is the highest point in the yard, so given that, they should at least have a degree of pressure. Given that the barrels are positioned upright, and about 3-4ft high, that will be enough pressure once they're full to power a soaker hose or garden hose?

Ken, could you post a link for the automatic flow valve? Also, what would the purpose of this be? Will it increase the psi overall? I have a "high flow" hose adapter at the outlet at the current time, here's a link to it:

http://www.amazon.com/Nelson-Rezimar-Kink-Free-Adapter-50305/dp/B0015AUOR8

Would this give the same effect as an automatic flow valve if I partially close the valve on this adapter, or is an AFV different somehow?
Dave Miller


Joined: Jun 08, 2009
Posts: 399
Location: Zone 8b: SW Washington
    
  10
If you decide to use a pump, I think you would want an "on demand" pump something like this: http://www.pplmotorhomes.com/parts/rv-pumps-water/shurflo-pump.htm If you used a regular sump pump, those are typically switched on & off by a float valve, so you would have pressure for a minute or two, then you would have to wait until the sump refills, then it would come on again. I think that would be a frustrating experience. Here is a battery-powered on demand pump: http://www.youtube.com/watch?v=iRNnh-4O63I

This guy uses air pressure in his rain barrel: http://www.youtube.com/watch?v=BtBLN49a-Q8 Although I would think you rain barrel would have to be designed for that, otherwise it would leak air. There must be a one-way valve to let water in but not let air out.

Ken Peavey
steward

Joined: Dec 21, 2009
Posts: 2338
Location: FL
    
  68
Link is posted above.

Since the barrels are the highest point in the yard, opening a valve will allow the water to flow. No pump would be needed.
Your diagram shows an on/off valve. Hook up the drip lines, open it up, you should be good to go.
The automatic flow valve simply turns the water on and off for you, according to how you program it (very easy to do). Handy for those times you are out of town.


Markham Cornoit


Joined: Feb 15, 2012
Posts: 22
I am thinking of getting a rain barrel, but before I spend the money I'd like to know what to expect in terms of savings. Anyone have real life experience?
Rob Meyer


Joined: Nov 14, 2011
Posts: 103
Technically, the savings are endless. Also, it really depends on your personal situation. Last year my parents monthly water bill was in the hundreds. Thus the rain barrel system this year. If they had that in place then, they would have saved hundreds of dollars a month. I guess it really depends on the size of your system, the size of your garden, what you use it for, how often you need to water the garden, and how you use it. You'll obviously get more mileage out of a soaker hose system than you would with an aerial sprinkler system, just because of how much more efficient soakers are. Also, if you don't have much capacity, you may have to use city water, and thus the savings will be lower than if you spend a bit more to increase your capacity. Another example is if you have a small yard, your savings will be less than if you have a huge yard, which would need much more watering overall, and thus afford much greater savings were the water provided from the sky. The last example I'll give is based on soil type. If you have a very sandy, organic matter poor soil, you'll likely have to water more than someone with a loamy clay rich in organic matter, just because in the sandy soil, the water tends to leach out much more quickly, thus increasing overall water needs.

My system is 330 gallons, and we will be applying it with a soaker hose system. We will also have a pump for the regular hose, for areas that need special attention. Actually, we'll see if we need a pump, as we just got a heavy rain, and the barrels are now likely almost full. In any case, we're hoping to save quite a bit this year.
gordon Stanhope


Joined: Jun 27, 2012
Posts: 1
my system is eight hundred gallons. Connected by inch and half PVC pipe all barrels connected together. Had old poolpump that I put I inline. Can water anything or run a sprinkler on 50 ft hose. Can muve all the water in 30 minutes. Just another idea for you to consider
 
 
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