What Size Pressure Tank?

pabloesguapopabloesguapo Solar Expert Posts: 116 ✭✭
I mulling over what size pressure tank to use. I found this article that says bigger isn't always better.

http://www.cyclestopvalves.com/tanksizing_12.html

It's going to go on our house with 3 adults and 3 kids, with regular weekend visitors. We will be also watering a lawn and a pretty good sized garden.

I was thinking of the 119 gallon tank our host provides. http://www.solar-electric.com/wwt-120.html But after reading that article, I don't know. After reading that, I'm wondering if I should try to irrigate using some other method, like maybe directly with a pump instead of out of the tank.

Any suggestions?

-Paul
27 Kyocera panels, 6,500w
24 CG2 6v batteries, 48v, 630Ah
Midnite Classic 150 & Classic 150 Lite in "follow me" mode
(2) Outback fx3648 inverters
Generac ecogen 6kw backup generator
Mate3s

Comments

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: What Size Pressure Tank?

    As big as you can get.

    The article is talking about constant pressure systems, which run the pump more rather than rely on stored pressure. They have a narrower operating range and provide more consistent pressure. Not desirable in an off-grid application where you want to take advantage of "surplus" solar power to run the pump and store up water when the power is available and not have to run it when it isn't.

    Remember; they're trying to sell you something.
  • pabloesguapopabloesguapo Solar Expert Posts: 116 ✭✭
    Re: What Size Pressure Tank?

    I see. Cool. Thanks.
    27 Kyocera panels, 6,500w
    24 CG2 6v batteries, 48v, 630Ah
    Midnite Classic 150 & Classic 150 Lite in "follow me" mode
    (2) Outback fx3648 inverters
    Generac ecogen 6kw backup generator
    Mate3s
  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: What Size Pressure Tank?

    You want to 'tap into' the feed line for your irrigation before the pressure tank (at the well head?). That way the water really does not go into the Ptank but you get the Ptank effect on when the pump kicks in.
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,076 ✭✭✭✭✭
    Re: What Size Pressure Tank?

    Small Marine and solar pumps may have their service life shortened by too large of a pressure tank. Large tanks will lengthen the run time that a small pump is not designed for.
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • MangasMangas Solar Expert Posts: 547 ✭✭✭✭
    Re: What Size Pressure Tank?

    We have a 500 gallon pressure tank supplied by two underground 1,700 gallon Norwesco water storage tanks each with a 1/2 hp grundfos pump.

    Reason being, we don't like cycling the well directly off the pressure tank. Prefer running the well once or twice a week to top off tanks. Tanks also offer fire protection capability. Most important, if a water line is left open or breaks, water loss is limited to the tanks and well is quarantined from a constant supply demand.

    It's just like solar capacity, you'll use all of it eventually. We built the water system with a lot of headroom capacity and we're using it.
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF Custom House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
  • Blackcherry04Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: What Size Pressure Tank?

    With the advent of the 5 GPM diaphragm positive displacement pumps the necessity of having a pressure tank is negated for the average household. I have removed the my pressure tank and 3/4 hp pump it took to pressurize it and the power requirement it had. The pumping curve on a centrifugal pump is horrible as the pressure rises. 5 Gallons a Minute is a huge amount of water @ 50-60 PSI, these pumps will keep up with your demands. Under some situations you could parallel 2 of them, but it would be a heck of a lot of water. Just pump from your well to a open loop storage tank @ zero back pressure once a week or so. You'll be surprised how you well pump will work without any back pressure. Make sure you size your storage tank to your use and ability to re-fill from your well. I don't like to store water more than a week and have mine sized to I turn over with fresh water once a week, 500 gallons.

    Just a thought for you, especially if your off-grid.

    http://www.energybay.org/aquatec-550-pressure-pump-120vac
  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: What Size Pressure Tank?
    Mangas wrote: »
    we don't like cycling the well directly off the pressure tank. Prefer running the well once or twice a week to top off tanks.
    Just curious. Having lived my life in rural Canada where everyone has their own domestic water systems, pumps, tanks etc, including myself, and all of us having been brought up on such systems, the idea of only cycling a well once or twice a week is foreign to us, thus I'd like to know the reasoning behind it.
  • MangasMangas Solar Expert Posts: 547 ✭✭✭✭
    Re: What Size Pressure Tank?

    We live near the Mexican Border in a very remote, mountaneous and unpopulated area. There is constant and costly property vandalism here to our infrastructure.

    Through experience, a segregated and protected well (and pipelines) with separate water storage can save a lot grief and money. Also, if a well goes off line, supply is assured to the house and livestock until repairs can be made which can take awhile. The well and one pipeline supplying the house is 1/2 mile from the household storage tanks.

    Our pressure tank, pump controls and water line valves are under double lock and key as are our storage tanks' pump circuit breakers. The tanks supplying the house (with manhole risers and electrics) are buried too.
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF Custom House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: What Size Pressure Tank?

    WOW!!!! So many of us, all of us where I live, have totally no idea how lucky we are, both with our water supplies, and the overall peacefulness and security of our land. What you have to deal with is almost beyond our imagination. I thank you for the education, and I wish you the best possible.
  • MangasMangas Solar Expert Posts: 547 ✭✭✭✭
    Re: What Size Pressure Tank?

    Thanks Wayne. It's a constant struggle for us.

    You are fortunate to live in such a beautiful and secure place. Many years ago, I travelled through Canada's back country and couldn't get enough of it.

    If you could send us a little of your bountiful rain down here, we'd surely be grateful.
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF Custom House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: What Size Pressure Tank?
    Mangas wrote: »
    If you could send us a little of your bountiful rain down here, we'd surely be grateful.

    I'd be glad to send a few million gallons your way, especially if it meant I could shut the gen down. It's raining again!

    Okay, so we need about 5,000 miles of pipeline ...
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: What Size Pressure Tank?

    sidenote:
    now that you guys have hit on the rainfall, i was thinking it has seemed to be less rainy here and so i decided to look at the nws data for here. if i'm reading this right it seems we are at a rough 50% deficit for the month of june so far. i didn't look at may, but i would imagine we had more sunshine back then too than usual as i am used to seeing 2 days of sun then a day of rain which follows the fronts that usually move through about that often. i have been seeing 5 and 10 day forecasts for some time now that often showed 4-5 days of sunshine and then a day they call for rain. the current 10 day forecast shows 2 days of rain and the percentages are low for one day and 60% for the other. when we got rain recently it hasn't been so much the long drawn out soaking rains we usually get either as it has been more abrupt with harder rains or we just didn't see much at all as we were hit by popcorn variety rain cells.

    update as of june 14.
    they changed their forecast. no rain is predicted here in the next 10 days over about a 20% chance. this is rare for pittsburgh.
  • MangasMangas Solar Expert Posts: 547 ✭✭✭✭
    Re: What Size Pressure Tank?

    I don't have a reflector large enough to help you guys out. They closed the last mountain heliograph station here at the turn of the century.

    Our summer rains don't start until July 4th and run through about September. After that, we're on our own. Problem is our 4 inchers tear up the canyons big time and don't deliver the moisture uniformly. We've been under drought conditions for sometime. Our winter snow pack has been a little sorry to boot.
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF Custom House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: What Size Pressure Tank?

    Niel;

    Not to get too far off topic but the weather has been very odd here. A day or so of sun, followed by torrent. Totally abnormal for June here. What is worse is that they can't keep up with the forecast; it changes every few hours by drastic amounts. Right now they say tomorrow will be sunny, Saturday back to rain. We'll see if it holds.

    What this does have to do with solar is the fact that panels only produce when the sun shines, and it is wrong to count on that all the time. In case anyone was wondering, that's why I cry "you need more panels!" all the time. Better to have a surplus on sunny days than a debilitating shortage on those less-than-sunny days. On days like these you'd need 10X the normal amount to charge from solar, and the day-after-day aspect of the rain makes it quite impractical to have enough battery on hand to "see through" the rainy spells. Normally you'd judge the weather for your area and plan accordingly. But that assumes you can count on the weather being predictable!
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,076 ✭✭✭✭✭
    Re: What Size Pressure Tank?
    Just curious. Having lived my life in rural Canada where everyone has their own domestic water systems, pumps, tanks etc, including myself, and all of us having been brought up on such systems, the idea of only cycling a well once or twice a week is foreign to us, thus I'd like to know the reasoning behind it.

    In the southswest US offgrid homes often cycle wells to fill the required 2,500 gallon (or more) tanks for fire suppression. Since most offgrid home are 2 people or less once the tanks are full we cycle wells. Very common strategy! They are all different but running (pretty deep) wells during non sunlight hours is not desireable, for many reasons!

    In winter when the landscaping is not using water the well often does not run for months in the this part of the world. It does not need to!
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: What Size Pressure Tank?

    Thanks Dave. Once again it makes me realize that the water we here have at out fingertips 24/7/365, is NOT the standard, even in North America, the land of plenty.
    We are so very lucky and don't realize it.
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,076 ✭✭✭✭✭
    Re: What Size Pressure Tank?

    Agree! very lucky! Almost as lucky as most all of us were in the war of 1812........
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: What Size Pressure Tank?
    Agree! very lucky! Almost as lucky as most all of us were in the war of 1812........

    Okay, let's not go there please.
    I don't want to have to start teaching history again. :p
  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: What Size Pressure Tank?
    Agree! very lucky! Almost as lucky as most all of us were in the war of 1812........

    Unless you lived in Washington, DC http://en.wikipedia.org/wiki/Burning_of_Washington
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: What Size Pressure Tank?

    *ahem*
    You too, Eric.

    Let's all remain friends and allies. :D
  • MangasMangas Solar Expert Posts: 547 ✭✭✭✭
    Re: What Size Pressure Tank?

    I can't recollect how old I am anymore which proves age is state of mind. . .
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF Custom House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,076 ✭✭✭✭✭
    Re: What Size Pressure Tank?
    westbranch wrote: »
    Unless you lived in Washington, DC http://en.wikipedia.org/wiki/Burning_of_Washington

    It is pretty hard to decide who the winners were after the 1812 War. There was so much military incompetence! Much easier to see that unfortuanately the Indians were the losers! Back to pressure tanks.
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

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