deepwell large volume solar powered water pumps

SystemSystem Posts: 2,511 admin
This is my fist time that I have attempted to reach out for help in providing a solution to a problem I have.
I would greatly appreciate constructive advice with the potential of acquiring the necessary hardware

I have piece of remote farm land that in order to convert in a economically viable venture requires the ability to access water from a depth of 200 metres with a flow rate of min 1000 gallons per minute. for use during daylight hours. All I have read indicates that this is not possible using solar power. could anyone confirm this and or suggest an alternative.

Regards
desrtgreen. :(

Comments

  • BB.BB. Super Moderators, Administrators Posts: 31,680 admin
    Re: deepwell large volume solar powered water pumps

    Well... We can sort of get an order of magnitude of the problem using standard solar pump data (large PDF file, right mouse click and hit Save As to download)... On page 22, lets pick the "6 SQF-2" with 1,000 watts of solar panel, sunny central US (you may have more sun--but we are just doing a SWAG calculation here), a 200 meter head is ~660-700'. These pumps are only good to ~350'--so we will have to double the power requirements to get "your theoretical" pump's ratings:
    • 6 SQF-2
    • ~350' 2,000 Gallons per day
    • ~1,000 watts of solar panels
    • Your pump = 2,000 watts of solar panels for 700' lift for 2,000 gallons per day
    Next page seems to indicate that a 6 SQF-2 pump will do about 3 Gallons per Minute
    • 1,000 GPM / 4 GPM per = 250 equivalent pumps for 350' lift
    • 700' lift would be ~2,000 watts of panels
    • 250 pumps * 2,000 watts = 500,000 watts of solar panels
    • system would give ~1,000 GPM from 700'
    • system would provide 250 * 2,000 GPD = 500,000 Gallons per Day
    So--that gives us a first order estimate of the power and capabilities of such as system.

    I would guess that this is somewhere around Saudi Arabia... So, sun is probably not an issue for you.

    What do solar panels cost for your area (in the US, $1-$5 per watt)--probably on the order of $1-$2,000,000 to just install the required solar array.

    Regarding the pumps--do you have any electrical pumps sized for the well field? kWatt rating? Voltage? Phase?... It would be interesting to see what a professional pump guy would size for your requirements using standard electric technology.

    It would not be impossible to design an Electronic Control system that could take the DC solar panel power in and convert it to variable frequency AC voltage to drive 3 phase AC pump motors. This is what the smaller pumps do.

    The other solution would be possible if you have AC power to the site and/or Diesel AC Gensets.

    Basically, make the solar power a 250-500 kWatt Grid Tied Power station. You use the AC Grid / Diesel Gensets to "create the Grid" and use the Grid Tied Solar system to supply AC power in parallel with the "traditional AC Power Sources" to off-load much of the energy from the Gensets/AC Mains...

    That could possibly done today with off-the-self equipment... The issue is the "feedback and control" if using Diesel Gensets--you have to share the load with solar+gensets in such a way that both are happy (gensets cannot be back driven and require 50-60% minimum rated power to be efficient/clean burning). If you have AC grid from the national utility available--then you have the issues of a Grid Tied Solar system tied to their grid--both engineering and political issues there.

    So--is the funding possible/practical for such a system?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2System2 Posts: 6,290 admin
    Re: deepwell large volume solar powered water pumps

    Thank you for your prompt reply, You assumed correct that the requirement is for Saudi. The capital expense could be justified if the generated capacity was capable of generating the electrical requirements of the other aspects of the farm and staff living quarters etc.
    What sort of area would the array of solar panels cover ?
  • BB.BB. Super Moderators, Administrators Posts: 31,680 admin
    Re: deepwell large volume solar powered water pumps

    You are welcome.

    I would have guessed that the foot print of array was not a large concern... And it is variable.

    You have the choice of $1 per watt thin film panels which are 1/2 as efficient as the $2-$4 per watt crystalline solar panels (and there is a little variation in crystalline solar panel efficiencies too). So, you will have a 2:1 variation in array physical size based on cost/availability issues.

    Depending on a lot of factors
    , your ground coverage ratio will probably be on the order of 0.3-0.6 : 1

    Lets use a lage 215 watt Kyocera panel--we get:
    • 1.5 meter * 0.99 Meter * 1/0.215 kW =6.9 sq.mtr per kW
    • 500 kW * 6.9 sq.m. per kW * 0.5 coverage factor = 6,900 sq.mtr = 74,270.9 sq.ft.
    Remember that solar power puts significant costs on large systems... For example, lets assume your well field will operate near capacity 8 hours per day of sunlight. That means the field would have to be 3x larger (more pumps, more wells, more electrical cabling, etc.) because it is only pumping 8 hours out of 24 hours per day.

    Also, you mentioned living quarters... You will want electric power 24x hours per day. For solar, lets assume that you get >6 hours of full sun per day for 9 months of the year. The derating factors are, roughly:
    • 0.77 for solar panel + charge controller * 0.80 for batteries * 0.85 inverter efficiency = 0.52 end to end efficiency/marketing derating
    So, if you have a 10kW (10,000 watt array) to power the office/living area:
    • 10,000 watts * 6 hours of full sun per day * 0.52 derating = 31,200 WH = 31.2 kWhr per day
    The same thing worked out using the PV Watts program for Abu Dhabe ARE (nearest point I could find):
    "Station Identification"
    "City:","Abu"
    "State:","ARE"
    "Lat (deg N):", 24.43
    "Long (deg W):", 54.65
    "Elev (m): ", 27
    "Weather Data:","IWEC"

    "PV System Specifications"
    "DC Rating:"," 10.0 kW"
    "DC to AC Derate Factor:"," 0.520"
    "AC Rating:"," 5.2 kW"
    "Array Type: Fixed Tilt"
    "Array Tilt:"," 24.4"
    "Array Azimuth:","180.0"

    "Energy Specifications"
    "Cost of Electricity:","-99.0 dirham/kWh"

    "Results"
    "Month", "Solar Radiation (kWh/m^2/day)", "AC Energy (kWh)", "Energy Value (dirham)"
    1, 5.68, 823, "N/A"
    2, 6.67, 864, "N/A"
    3, 6.14, 878, "N/A"
    4, 6.56, 883, "N/A"
    5, 7.17, 974, "N/A"
    6, 7.03, 911, "N/A"
    7, 6.85, 903, "N/A"
    8, 7.10, 937, "N/A"
    9, 7.13, 920, "N/A"
    10, 6.81, 936, "N/A"
    11, 5.98, 820, "N/A"
    12, 5.39, 782, "N/A"
    "Year", 6.54, 10632, "N/A",
    Note the third column is kWatt*Hours per Month. Based on a 10,000 Watt / 10 kW array:
    • Feb 6.14 Hours sun per day => 878 kWH per month / 30 day/mnth = 29.3 kWhrs per day
    The PV watts program has some options you can play with (tracking arrays, mounting tilt, etc.). Also, you can do hourly output and see what the average power output put is by hour by day for a year (this is real data based on 20 year or so average weather conditions).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • icarusicarus Solar Expert Posts: 5,433 ✭✭✭✭
    Re: deepwell large volume solar powered water pumps

    Anything can be done if you are willing to pay for it. 1000 gpm from 200 meters is going to be very expensive. What about mechanical wind pumping? Perhaps the 1000 gpm might drop to ~250 if you could pump 24 hours. I know nothing about wind pumping but since people have been doing it for a long time, there should be lots of information out there.

    Tony
Sign In or Register to comment.