Power for well

[firegirl969]

Our well is 220. We are considering putting a water tank outside about 10-12 feet in the air that will hold several hundred gallons and plumb it into the water line coming from the pumphouse. Would it be realistic to make the pump in the pumphouse solar powered or would it be better to use the 8000 watt generator we already have, as long as we can get gas to power it? I know it would be cheaper to use the generator since it is paid for. How would we fix the electrical parts on the pump to be able to use the solar or generator? Thanks in advance for the help, firegirl

[Travis]

Not the answer you ask for but why cut out the electrical to start and go with a gas powered pump to start with?? It would take quiet a few panels to run the pump and on days when you have lots of cloud cover you may not have the solar to use it and would have to rely on the generator anyway.

[randallhilton]

I like the storage tank idea.

I think you would need to switch to a different kind of pump if you want to use solar. The gravity storage tank gives you the ability to use a lower flow rate since all you're doing is filling the tank instead of pressurizing it on demand.

For example. . . let's say you get 3 hours of good sunlight in a day. If your pump could deliver a gallon a minute for 3 hours a day you'd have 180 gallons available every sunny day. Size the tank according to your needs, average sun and pump capacity so that you can get through the cloudy spells. Keep the genny handy for longer cloudy spells.

[12vman]

How deep is the well?

By using your existing pump and a generator, you could fill a nice sized tank in a short time. A submersible pump will move a lot of water at free flow. (If your well has enough return to keep up with the pump) You could possibly fill a 700 gal. tank in a half hour run time with the generator.

You wouldn't need to alter your existing pump to work with a generator if the generator supplies 220 volts and enough current. (Wattage) How many h.p. is your pump? If you already have an 8K generator, that should handle most pumps.

Trying to supply your existing pump with solar will be very expensive. If you decide to go the solar route, you would need to replace your pump to make it feasible.

[MissouriFree]

A elevated tank is a great way to have water during an emergency without having the need for a generator but it will probably not supply the pressure you are accustomed to . A tank 15 feet above you house will only give you about 7 PSI (. city water is usually 40 PSI). you will still probably need a pressure pump system.

what a tank does for you though is:

1. give you a supply of water during loss of power with out having to have a generator.
and
2. if plumped correctly ( single pipe to tank) can extend the live of your deep well pump.

we had another thread that touched on this before. I was thinking of a windmill but I live in deep well area.

http://www.backwoodshome.com/forum/vb/showthread.php?t=15792


the best book on rural water systems i have see is
Waterworks- an Owner-builder guide to Rural water systems

mo

[Anon001]

Where I was raised, our wells were all at least 300 feet. At one time, they were all pumped by windmills.

Once the water is in a tank.... I have a 12 volt Shurflo diaphragm pump that pulls water from the tank and fills a pressure tank. The pressure tank supplies about 30 pounds pressure, I think. The pump only comes on once the pressure tanks empties. This extends the life of the pump versus, contintually shutting on and off when a water faucet is opened.

I would do as 12vman suggested and fill the tank by using the generator to pump the water. Then for about $70 to $100 you can get a nice little Shurflo pump. The pressure tank I have was scavenged, sorta... okay I stole it. lol

You actually have a lot of options, just think outside the box.

Paul

[12vman]

It's possible to increase the pressure from a raised tank by making the drop line from the tank towards the ground as big in diameter as possible and as long as possible. Gravity and mass can be your best friend at times..

Let's say the holding tank is 15' off the ground with a 1" output at the bottom. Get a 10' section of 12" I.D. PVC with end caps. Mount a 1" input pipe connector in one of the end caps and a 1/2" output pipe connector on the other. Glue the end caps to the 12" PVC. Mount the 12" PVC pipe vertically below the holding tank. (One end up,(1" pipe connector end) Other end towards the ground) Connect the 1" connector on the tank to the 1" connector on the PVC. (Of course, mount (hang) the 12" pipe solid because it's going to be heavy when it's full of water) Connect to the 1/2" connector on the bottom and run it to where you need to. I'll bet you don't need a pump to pressurize the water.. ;)

[randallhilton]

Not to be pesky but the size of the container (pipe) doesn't change the head pressure. The pressure at the faucet will be determined by the elevation difference between the faucet and the water level of the tank regardless of the size of the pipe.

Pipe size could cause a pressure drop if it's too small, but big enough is just as good as anything bigger.

[MissouriFree]

Hmmmmm..

I'm pretty sure that Pressure is only repeat only related to the vertical distance beween the top of or arrangement. water level and point of disbursement and not pipe lenght or size. that is what is call " head pressure" and it does not even vary with the amount of water ( small tank or big tank) all that counts is the hight of the water compared to the point of disbusement . The more precise number is .433 PSI per foot of water height.


Randal you beat me to it.l

[cinok]

I need to ask what part of the country are you in is freezing a problem?

[12vman]

"I'm pretty sure that Pressure is only repeat only related to the vertical distance beween the top of or arrangement. water level and point of disbursement and not pipe lenght or size. that is what is call " head pressure" and it does not even vary with the amount of water ( small tank or big tank) all that counts is the hight of the water compared to the point of disbusement . The more precise number is .433 PSI per foot of water height."

This may be true BUT the fact of having a larger supply from the elevated tank than a small size pipe can provide at ground level will help in the amount of flow without restriction at the point of release. In turn, more flow potential to the service line. The pressure may not be great but you will get much more flow without restriction.

Using a smaller I.D. pipe from the elevated tank to ground level will reduce flow because of friction, which in turn, reduces pressure and flow potential as the water is running. The pressure might be there when the water is shut off but the pressure will drop off quickly if a single, smaller size pipe is used from the elevated tank to ground level. The potential will not be there to replace the pressure drop so you will have less flow.

By using a large supply pipe from the elevated tank, all risk of friction is gone and all possible pressure and flow potential is at ground level to the supply line. Being that there is no friction from the supply tank and the sudden pressure drop can be replaced immediately, there will be more flow possibility to the supply line. The only losses you would see would be in the supply line itself.

http://home.earthlink.net/~mmc1919/venturi.html

[MissouriFree]

"I'm pretty sure that Pressure is only repeat only related to the vertical distance between the top of or arrangement. water level and point of disbursement and not pipe length or size. that is what is call " head pressure" and it does not even vary with the amount of water ( small tank or big tank) all that counts is the height of the water compared to the point of disbusement . The more precise number is .433 PSI per foot of water height."

This may be true BUT the fact of having a larger supply from the elevated tank than a small size pipe can provide at ground level will help in the amount of flow without restriction at the point of release. In turn, more flow potential to the service line. The pressure may not be great but you will get much more flow without restriction.

Using a smaller I.D. pipe from the elevated tank to ground level will reduce flow because of friction, which in turn, reduces pressure and flow potential as the water is running. The pressure might be there when the water is shut off but the pressure will drop off quickly if a single, smaller size pipe is used from the elevated tank to ground level. The potential will not be there to replace the pressure drop so you will have less flow.

By using a large supply pipe from the elevated tank, all risk of friction is gone and all possible pressure and flow potential is at ground level to the supply line. Being that there is no friction from the supply tank and the sudden pressure drop can be replaced immediately, there will be more flow possibility to the supply line. The only losses you would see would be in the supply line itself.

you got that right.. even though there is no way to increase head pressure without changing the water hieght , pipe size and type are most important. Actually it is best to use the largest size pipe you can afford as that larger size the less effects of pipe wall due to pipe wall friction. you can't completely eliminate it but larger is better.

larger diameter pipe promotes greater flow rates. In addition it is best to use plastic pipe is has least pipe friction and is least susceptible to corrosion or scale buildup.

[12vman]

Well.. We got it figured on how to get the best bang at 15', Now we need to figure on how to get the water from the well to the tank... LOL ;)

[randallhilton]

[i]
By using a large supply pipe from the elevated tank, all risk of friction is gone and all possible pressure and flow potential is at ground level to the supply line. Being that there is no friction from the supply tank and the sudden pressure drop can be replaced immediately, there will be more flow possibility to the supply line. The only losses you would see would be in the supply line itself.

You are correct that friction loss is a factor to be considered. That's one of the things we plumbers design for. But for a typical home, a 12" water pipe is a bit of an overkill. Without knowing usage requirements I would guess 1" would be big enough to mitigate pressure loss. (and I acknowledge that at lower pressures, loss is more critical which is why we design accordingly).

Size matters more as the distance increases but 15' of 12" pipe won't make a noticeable difference no matter how long the developed length of the line.

To make an electrical analogy: You could install size 00 cable to run a 12v, 25w light bulb a hundred feet away but that bulb is probably not going to shine any brighter than if you used #12.

If the energy source is 12v then no matter how large the cable, it's not going to be more than 12v at the other end.

I'm probably being clear as mud. :o)

[12vman]

"Clear as mud".. LOL.. Naa.. You just missed the concept a little..

We have a water holding tank 15' in the air that is unpressurized. An open tank full of water. Mother Nature is providing the water pressure with gravity. According to Missouri Free, we're only dealing with around 6.5 lbs. of pressure. I presented my thoughts on how to get the best bang for the height to avoid friction losses. I agree that 12" pipe might be a little overkill but in this case, the bigger the better to avoid any losses whatsoever being we don't have much to play with from the get go..

[firegirl969]

We live in south GA, so normally freezing is not an issue. Our well is about 225 ft deep. Our pump is 3/4 hp. I think that answers the questions so far. Thanks for the help, firegirl

[kawalekm]

Not the answer you ask for but why cut out the electrical to start and go with a gas powered pump to start with?? It would take quiet a few panels to run the pump and on days when you have lots of cloud cover you may not have the solar to use it and would have to rely on the generator anyway.

Just to let you know, gasoline powered pumps are designed for moving large volumes of water from "low head" locations by SUCTION, which means they can only SYPHYN water a few vertical feet. In fact, the theretical maximum that a suction pump can lift water is only about 32 feet, under atmospheric pressure.

For a water well deeper than 32 feet, you MUST use a submersable pump that PUSHES water, not pulls it. Older windmill pumps had a long metal rod that extended the depth of the well to motivate the submerged pump. Today, electricity does the same thing.

[Pitdog]

So Riddle me this- Firegirl asked the EXACT same question I was going to- But bottom line is cost. How much to run a submersible pump and keep water going without grid fed electricity?
I'm thinking our pump runs on 110, well is about 150 feet deep. Should I look at other options? I want to be able to run a freezer and a well pump. I'm not much worried about anything else. However the only source for water on our place is the well.
suggestions?

[patience]

One horsepower is 746 watts, so to run a 3/4 HP pump would require on the order of 600 watts, including inefficiencies. Starting current is much higher, but only lasts a few seconds. If this pump starts and stops, the total power draw is higher due to starting surge, but run continuously for an hour would need maybe 700 watt hours.

To run that on solar would take a 175 to 200 watt panel in full sun (not likely this time of year) for 3 to 4 hours = about all you can expect at mid latitudes in the US. To get you through normal cloudy weather, I would want at least 2 of those panels. Then, you need enough batteries to store the power for when you actually use it. At 12 volts, 700 watts = 35 amps for an hour. To keep the battery draw at a reasonable level, say a max of 35% discharge, the battery bank would need to have at least 100 amp hours. But, since the RATE of discharge is important, the battery needs to be even larger to keep the rate at under the 20-hour rate, usually. High discharge rates will shorten the ultimate battery life, so a really heavy duty deep cycle battery is in order, like a small forlift battery, of about 1,000 amp hours capacity.

Those 2 panels could cost around $1,000 to $1,500, the battery would be at least that much, and you haven't bought a charge controller or wiring, fusing, and installation yet. The above would make a very durable system, but it ain't cheap. You never get any more than you pay for, as a rule.

Bottom line is, like 12vman said, solar would be costly. Find another way, if possible.

Anyone with more expertise then me on the above, would be a help here!

edit to add: Seems to me lke the answer for using solar would be a small pump to fill the storage tank over a longer period of time, as others said.