Suggestions for water pumping

roksroks Solar Expert Posts: 28
I am looking to replace a extremely noisy 750watt 240v AC pump. I am finding this pump is not very effient as its not pumping much as it used to and because its inside the house, the noise is unbareable while its running.

I was thinking of going solar with 12/24v pump to kill the noise and at the same time save on electricity bills.

I like to know how I would go about installing a solar powered pump, it doesnt need to have battery backup, just run while the sun is up.

I have attach the current layout, the pipes are few feet underground, I think they 3/4" or 1".

I am not worried about the speed too much, it just needs to be able to fill the tank, 5ftx5ftx5ft.

Thanks in advance.

Comments

  • BB.BB. Super Moderators, Administrators Posts: 32,212 admin
    Re: Suggestions for water pumping

    Rok,

    I forget where you are at (Belgium?).

    Is there anyway you can install the pump near the pond (including issues with subfreezing weather) or run a submersible pump in the lake?

    Or dig a 10'+ deep pit next to your home and put the pump in it so that you can have a lower head or positive pressure from the pond water?

    Digging a deep pit has its own issues and is probably not practical anyway--unless you have a basement and/or natural geography to help (such as the pond is behind a dam, and your property is lower than the pond--and you would need to plan for a broken pipe/pump possibly flooding your basement, etc.).

    Lifting water up 10' and pulling it 190' would seem to run the risk of cavitation/drawing a vacuum in the pump inlet--leading to loss of prime/low pump flow, noise, and possible damage/extra wear. Even pumps designed for lifting water cannot lift more than 20-25' of water column due to air pressure limitations (not including the drag and momentum issues of pulling the water through 190' of pipe).

    Unless you need solar power (off-grid)--a better pump selection/installation running from grid power may be a better solution all the way around (long life, lower costs, no issues of 24 vdc conversion).

    And even for an off-grid application, if you already have 240 VAC available--it is better to send the 240 VAC 190' to the pond then to try and send 24 VDC to the pond--You would need 10x the amount of copper (and 10x as expensive) because of the higher current a 24 volt pump would require vs the same power at 240 volts.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • roksroks Solar Expert Posts: 28
    Re: Suggestions for water pumping

    Hi BB.

    Place is in Bangladesh, I dont think I've ever seen freezing temp, probably about 5-6deg C, no snow or ice, just foggy and cold in the winter months but all disappear by 10am.

    No space to digg pit and placing the pump out side the house is a bit risky, tropical monsoon weather and theft are an issue.

    What is the difference between having the pump near the pond and inside the house?

    I was also thining of digging down a making a underground concrete box, with a slab to cover it.

    When you say "drawing a vacuum in the pump inlet", I think we experienced this, we had to unscrew a cap on the pump and pore water in it, then it starts to pump the pond water. I was led to beleive that normal with all pumps, if they are not used for a while.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Suggestions for water pumping

    The first question I would ask is: why not replace the existing pump with a comparable model? It would probably be cheaper than a direct solar pump, and more readily available. So would you really be saving enough on electricity to make it worthwhile? Or is the electric so unreliable there that it becomes an issue? Your old pump is probably inefficient and noisy because the pump is worn.

    Regarding pump placement, the closer to the source the better. Basically this is because it is easier for a pump to 'push' water than to 'pull' it. No, you should not have to be 're-priming' your pump every time you want to get water; this indicates a problem either with the pump, or leaking/incorrectly sized intakes, et cetera.

    As far as direct solar powered pumps are concerned, they are pricey and may not be readily available in your area. Grundfos makes very good - and very expensive - units. So does Shurflo. Most of these units are submersible type.

    To size the pump you need to know how deep your draw is, how far away, and what kind of volume/pressure requirements you have.
  • BB.BB. Super Moderators, Administrators Posts: 32,212 admin
    Re: Suggestions for water pumping

    Roks,

    Take a read through this Pump 101 type tutorial--it is geared more towards irrigation pumps--but the basics are the same as yours.

    In the end, pumps with positive pressure (i.e., below the water level) are usually more efficient.

    However, you have the other issues (water leaks, maintenance) and possibility of theft.

    In the end, you might be better off with a less expensive submersible pump in the lake with 240 VAC wiring assuming that less life and possible theft make up for the other issues.

    Or just keep replacing the in-home pump you have as this ends up being the lower cost.

    Running a smaller pump 24 hours per day, vs a large pump 1 hour per day may also offer advantages (lower pump replacement costs--can afford a "better" pump for your application).

    Checking with your local pump supplier might be able to suggest good alternatives for your installation.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.BB. Super Moderators, Administrators Posts: 32,212 admin
    Re: Suggestions for water pumping

    PS: Would a shallow well next to your home be practical?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • roksroks Solar Expert Posts: 28
    Re: Suggestions for water pumping

    BB.
    Thanks for that link, very informative, will read thoroughly. Only well possible is a deep well, ones where they burry 4" pipe into the ground and attach a pump. They are not ideal due to Arsenic.

    Cariboocoot
    I dont think I'd be saving much just that electricity supply is mightmare, so that made solar look ideal. Anyhow, I dont think its going to be a straight foward as I would have liked, so I'll be looking into better model AC pumps. And then burry the pump underground to kill the noise a bit.

    Thank you both for the info.
  • solarixsolarix Solar Expert Posts: 713 ✭✭
    Re: Suggestions for water pumping

    Almost any kind of positive displacement solar or DC pump is going to put pulsations into the water which you will be able to hear anywhere along the pipe that it presurizes. Need one that is a constant rotation like a vane pump like used on irrigation sprayers. Downside is they have more friction and are less efficient but more reliable. Not a problem if you run it on AC though.
  • System2System2 Posts: 6,290 admin
    Re: Suggestions for water pumping

    Hi Roks

    Considering you have to put up with all that noise suggests something is not quite right with your system!

    I would use a good sprinkler pump to pump the water up from your pond to your tank.

    One thing that interested me was you're considering going solar powered?! I don't know if you're in the UK but i know several people who are getting £20,000 solar panels placed on their roofs for only £500. It's government subsidised along with private companies who make their money back by selling the excess power back to the national grid.

    You get free power. I have to look into this as it's the direction i'm going to be heading in.

    Hope this helps.
  • icarusicarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Suggestions for water pumping

    A simple way to cut down the noise from a diaphragm pump is to install a simple loop of pipe (PEX) between the pump and the tank. This way the loop absorbs much of the vibration. This works especially well with Shurflo RV type pumps. I have not bothered to do so on my shurflo 9300 system due to space considerations (and freeze protection) and besides, by having the pump make a bit of noise, I can tell when it is running and manage when it is running if I wish to time shift pumping to a more advantageous time.

    Tony
  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: Suggestions for water pumping

    My well is down over the hill about 250 feet from the house, and the water level approximately 18 feet below my piston pump in the basement. Been in use that way for almost 30 years, same pump. Photos here:
    http://forum.solar-electric.com/album.php?albumid=37
    I have 1 inch water line, and there used to be, for up to 2 seconds, the sound of cavitation until the water got up to speed in that 250 foot line, but once it got moving, no more problem. A few years ago, I lowered the pump, which was about 6 feet above the floor, down to about 3 feet, and that eliminated any sign of cavitation. Smaller diameter pipe would have more resistance, thus more cavitation. 1 1/4, or 1 1/2 inch pipe would in my case, eliminate any sign of cavitation, but I don't bother, it's no longer a problem.
    This pump moves about 300 gallons /hour. A lower capacity pump would move the water slower through the pipe, thus less resistance losses / less possibility of cavitation, and of course, the opposite with a higher capacity pump.
    By the way, this pump's motor is rated 1/4 hp, 5 amps @ 110 VAC.
    By the way #2: Sounds like you have to add water to re-prime your present pump. That indicates a defective, or leaking foot valve, allowing drain-back into your well. Also possible a non-stainless steel pipe clamp has rusted off at the foot valve, allowing leak-back to the well, possibly draining the water from the pump and requiring the re-prime.
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