And Now for a Petrol Pump

And now petrol pump Installation. Since meeting is on this Tuesday, so I want to get prepared.

Solar System for a petrol pump with
Appliances......................................Quantity...................Power...................Usage
fuel dispensing machines.................... 1............................750W...................30 minutes in one hour: 24 hours a day (On/Off condition)
Energy Savers ................................ 5............................. 24W...................18 Hours a day
Desktop Computer............................ 1..............................200W................. 12 Hours a day
2 Fans.............................................2..............................80W...................18 Hours

Total Power
750Watt of fuel dispensing machines: Surge Current 3x
480 Watt of other appliances.
Total 1220 Watts

Inverter Requirement: 5000VA Pure Sinewave
Panels Requirement : 1500~2500 Watt
Batteries Requirement: 12 v, 4 numbers, 200AH each.
Grid Voltage: 220

This system can handle 2 more fuel dispenser? (With 1000 to 2000 Watt extra panels installation)?

Am I right? What would be minimum and maximum panels required? :s

Comments

  • jcheiljcheil Solar Expert Posts: 722 ✭✭✭
    Re: And Now for a Petrol Pump

    Could you provide the location where this will be installed (i.e. city?)

    Are the power consumption numbers you listed above the ACTUAL amounts used (i.e. from a Kill-A-Watt meter) or just what the nameplate states?

    What battery voltage are you going to be running at? Because AH is a vague number unless we know the battery voltage.
    I am hoping 48v because don't expect to run a 5000VA inverter on 12v (and even 24v is pushing it). Although I don't think you need anywhere near a 5000VA inverter. A 2000VA would be plenty based on your loads (and even that is on the high end).

    And if those are the actual numbers, your are going to need a MUCH bigger system, both batteries and panels.
    The experts here can get it down to the exact numbers, but based on those loads and only a single day of reserve in your batteries I calculate around 750AH battery bank at 48v and around 6500watts of solar panels.

    This will not be a small system and thus quite expensive!
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
  • BB.BB. Super Moderators, Administrators Posts: 32,608 admin
    Re: And Now for a Petrol Pump
    Badar wrote: »
    Solar System for a petrol pump with
    Appliances......................................Quantity...................Power...................Usage
    fuel dispensing machines.................... 1............................750W...................30 minutes in one hour (On/Off condition)
    Energy Savers ................................ 5............................. 24W...................18 Hours a day
    Desktop Computer............................ 1..............................200W................. 12 Hours a day
    2 Fans.............................................2..............................80W...................18 Hours

    Just to address the questions about power usage... This is an example where the "heavy load" of 750 Watts (and the "reason" for a petrol station to exist) is not what will drive the design/costs of your off grid/backup power system:

    750 Watts * 0.5 hours of use per day = 375 WH per day
    5*24 watt "Energy Savers" * 18 hours per day = 2,160 WH per day
    200 watt desktop computer * 18 hours per day = 3,600 WH per day
    2*80 watt fans * 18 hours per day = 2,880 WH per day
    ==============================================
    9,015 WH per day total (that is not a small amount of power usage)

    Only ~4% of the power is actually used pumping gasoline.

    As "Jheil" asks, are these measured with a Kill-a-Watt hour type meter (here is a 230 VAC version from UK) or just from name plate ratings (almost useless for our needs).

    As interesting as Solar Power is--80% of the work will probably involved energy conservation.

    I have had these conversions before---You can get smaller laptop computers that will use on the order of ~8 watts average power consumption:

    8 watts * 18 hours = 144 WH per day

    A true desktop computer can be a real energy hog... They are getting better (using more of the techniques used by laptop computers to save power usage--And becoming a requirement for energy efficient desktop computers in many countries). But--The downside is that laptop computers are not always available/cost effective in other countries (import tariffs, etc.).

    You might search around for low power point of sale systems (i.e., smart cash registers) that may be available in your region of the world. Or--It could be a new business opportunity (use a small industrial computers+small screen+dc battery bank input for backup power+POS Software).

    Anyway--Somethings to think about.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BadarBadar Solar Expert Posts: 38
    Re: And Now for a Petrol Pump

    Well, I accept, data provided by me was in much stupid style. :D

    City: Rahimyar Khan, Pakistan
    Ratings: Name Plate Ratings, not by kill-e-watt-meter confirmation.

    Solution needed.
    1: Generator Replacement. (One hour load-shedding after one hour)
    2: Off-Grid Installation. (If Grid is disconnected in day time)

    My Calculations:

    1: For Off-Grid (With 5 hours back-up)

    DC Current Requirement @ 48V:
    Total Load/Grid Voltage= 1240/220= 5.63 * 5= 28.18A=30 Amp in one hour

    Panels Requirement:
    CanadianSolar CS5P-250M, Peak Power 250W, Imp= 5.14
    Total DC Current required/ Imp of panel = 30/5.14= 5.83 Panels = 6 Panels of 250 Watt each= 1500 Watt
    These panels can provide power to above load in 5 peak sun hours.

    Considering Inverter in-efficiencies, line losses, etc = 1500 watt/0.8= 1875 =1900 Watt Panel
    Considering Sun movement: Total Installation: 2500 Watt (Battery will negligibly used in day-time 8:00 AM to 5:00 PM)

    For Inverter sizing:
    Surge Current for 750 watt motor in fuel dispenser is considered three times i.e. 2250 Watt for few seconds.
    So I think even 3000VA will not support all this load if other load like fans, pc etc are running.
    5000VA inverter has added benefit for future extension i.e. extra fuel dispenser can be used on it, if required.

    Batteries Requirement:
    Since 30A are required to power all load for one hour.
    So for Five hours back-up: 30 * 5= 150A @ 48V
    Considering battery losses: 150/0.8= 187A= 200A @ 48V (4 batteries of 12v,200A on 48V formation)

    2: For Generator Replacement (2 hours back-up required, Grid will not be disconnected)
    Every thing same as above except panels.
    1000 to 1500 Watt panels would be sufficient. I think
  • jcheiljcheil Solar Expert Posts: 722 ✭✭✭
    Re: And Now for a Petrol Pump
    Badar wrote: »
    For Inverter sizing:
    Surge Current for 750 watt motor in fuel dispenser is considered three times i.e. 2250 Watt for few seconds.
    So I think even 3000VA will not support all this load if other load like fans, pc etc are running.
    5000VA inverter has added benefit for future extension i.e. extra fuel dispenser can be used on it, if required.

    A 2000 will do you fine. Most inverters can handle a certain surge current for several MINUTES (depending on the rating) and then a final maximum surge current for a couple of seconds.

    Like on my 3000w inverter, I can run continuous 3000w, 4500w for 20 minutes and 6000w for 2 seconds (or something along those lines).

    Like "bb" was mentioning, CONSERVATION is the most important thing. And if you get an inverter too big, you will waste even MORE power just having it sitting around at idle.

    But either way you are talking about a BIG BIG EXPENSIVE system unless you cut your loads way down. It will not even come close to working based on your original plans. Like I guessed: around 750AH battery bank at 48v and around 6500watts of solar panels - nowhere near your guess of 1000w-1500w in panels.

    Also calculate everything in WATTS, not AMPS. WATTS is much easier to work with and does not depend on knowing the voltage.
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
  • BadarBadar Solar Expert Posts: 38
    Re: And Now for a Petrol Pump

    Well, Dear Bill, I am unable to explain my point.
    Fuel Dispenser is being used 30 minutes in one hour of 24 hours. You can think of it as 12 hours a day operation.

    Taking your calculations
    750 Watts * 0.5 hours of use per hour= 375 WH per hour *24 hours = 9000 WH per day
    5*24 watt "Energy Savers" * 18 hours per day = 2,160 WH per day
    200 watt desktop computer * 18 hours per day = 3,600 WH per day
    2*80 watt fans * 18 hours per day = 2,880 WH per day
    ==============================================
    17,640 WH per day total
    ==============================================

    Grid Electricity will be used from 5:00 PM to 8:00 AM i.e.15 hours. i.e 63% of time.
    Out of it, 8 hours are of Load-shedding. (where battery support is needed)
    And 7 hours of Grid-Power.

    63% of 17,640 WH per day total =11,113 WH will be used in Grid-Power time.
    Watts used in one hour of night=11,113/15=741W
    So 741WH battery bank is required for one hour support.
    For 5 hours continuous support=741 * 5= 3705 WH will be required.

    Battery bank Installed
    4, 200AH batteries in 48V formation.
    48 * 200 = 9600 WH available.

    Am I Right?


    (In my above post, I used complete 750W of motor for calculations)
  • jcheiljcheil Solar Expert Posts: 722 ✭✭✭
    Re: And Now for a Petrol Pump
    Badar wrote: »
    Battery bank Installed
    4, 200AH batteries in 48V formation.
    48 * 200 = 9600 WH available.

    Am I Right?

    You never want your battery SOC to EVER EVER go below 20% and most suggest never below 50% so you would only have HALF of that capacity of whatever sized battery bank you have. But again, THAT BANK/SOLAR IS WAY TOO SMALL.
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
  • BadarBadar Solar Expert Posts: 38
    Re: And Now for a Petrol Pump
    jcheil wrote: »
    A 2000 will do you fine. Most inverters can handle a certain surge current for several MINUTES (depending on the rating) and then a final maximum surge current for a couple of seconds.

    Like on my 3000w inverter, I can run continuous 3000w, 4500w for 20 minutes and 6000w for 2 seconds (or something along those lines).

    Like "bb" was mentioning, CONSERVATION is the most important thing. And if you get an inverter too big, you will waste even MORE power just having it sitting around at idle.

    But either way you are talking about a BIG BIG EXPENSIVE system unless you cut your loads way down. It will not even come close to working based on your original plans. Like I guessed: around 750AH battery bank at 48v and around 6500watts of solar panels - nowhere near your guess of 1000w-1500w in panels.

    Also calculate everything in WATTS, not AMPS. WATTS is much easier to work with and does not depend on knowing the voltage.

    Well, I have discussed importance of conservation with Bill earlier. But problem is that there is nothing to replace. No huge difference for owner of Petrol/Gas pump

    Replacing E/S with LEDs will cut 96WH, and a Desktop with Laotop will cut down 200 WH, Total of 300WH. It will not put a big difference in electricity bill of gasoline station, or should I say it will be negligible for petrol pump owner. He is paying near to 100 thousand Rupees in term of electricity and fuels.

    So real issue is, why is so much difference in your calculations and mine.
  • jcheiljcheil Solar Expert Posts: 722 ✭✭✭
    Re: And Now for a Petrol Pump
    Badar wrote: »
    So real issue is, why is so much difference in your calculations and mine.

    The difference in your math vs mine and Bills is because you are still looking at it the wrong way.

    1) If you have a device that is using 200w, and will be running for 12 hours, then it will have consumed 2400watts. Bill did that for you based on your nameplate ratings. Your realistic numbers when you use a Kill-A-Watt meter "should" be less.

    2) You cannot assume that you will get 5 hours of sun and even if you do, the panels will not put out their maximum rating evenly throughout those 5 hours. So you cannot say I have 1000W of solar and 5 hours of sun means I get 5000w of power. Plus you need MORE power to put back INTO a battery than what you get out of it.

    As Bill and everyone has said here many times, KNOW YOUR LOADS FIRST, then use that to define a battery bank size, and then use that to determine the amount of solar you need. And in your case, you will need to know how long (in hours) you expect to be running off of battery power each day.

    You might just consider skipping the solar alltogether and just use a charger when your grid power is up. It would save a bunch of money.

    NOTE: I just realized you are using that pump 30mins EACH hour 24hrs per day which means the system will need to be even BIGGER!
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
  • BB.BB. Super Moderators, Administrators Posts: 32,608 admin
    Re: And Now for a Petrol Pump

    I am sorry Badar... I need to read the posts much more closely than I am. :blush:
    Badar wrote: »
    Well, Dear Bill, I am unable to explain my point.
    Fuel Dispenser is being used 30 minutes in one hour of 24 hours. You can think of it as 12 hours a day operation.

    Taking your calculations
    750 Watts * 0.5 hours of use per hour= 375 WH per hour *24 hours = 9000 WH per day
    5*24 watt "Energy Savers" * 18 hours per day = 2,160 WH per day
    200 watt desktop computer * 18 hours per day = 3,600 WH per day
    2*80 watt fans * 18 hours per day = 2,880 WH per day
    ==============================================
    17,640 WH per day total
    ==============================================

    Grid Electricity will be used from 5:00 PM to 8:00 AM i.e.15 hours. i.e 63% of time.
    Out of it, 8 hours are of Load-shedding. (where battery support is needed)
    And 7 hours of Grid-Power.

    63% of 17,640 WH per day total =11,113 WH will be used in Grid-Power time.
    Watts used in one hour of night=11,113/15=741W
    So 741WH battery bank is required for one hour support.
    For 5 hours continuous support=741 * 5= 3705 WH will be required.

    Battery bank Installed
    4, 200AH batteries in 48V formation.
    48 * 200 = 9600 WH available.
    • 3705 WH * 1/0.85 AC inverter eff * 1 day storage * 1/0.50 maximum discharge * 1/48 volt battery bank = 184 AH @ 48 volt battery bank

    The recommended AC charging for such a battery bank would be around 10%-13% typical--And upwards of 20-25% maximum (with battery thermal control).

    I am not sure that solar makes sense for this application... You will have to decide tradeoff between AC Mains/Generator/Solar charging... But to charge that battery bank from solar, reasonable array sizes would be from 5% to 13% typically:
    • 184 AH * 59 volts charging * 1/0.77 panel+controller losses * 0.05 rate of charge = 705 Watt array minimum
    • 184 AH * 59 volts charging * 1/0.77 panel+controller losses * 0.10 rate of charge = 1,410 Watt array nominal
    • 184 AH * 59 volts charging * 1/0.77 panel+controller losses * 0.13 rate of charge = 1,833 Watt array "cost effective maximum"
    You could go larger with solar if you want to support the running loads at the same time:
    • 741 Watt average AC loads * 1/0.77 panel+controller derating = 976 Watts of panels added to above array to charge and sustain during daylight time (i.e., proper battery charging current + AC loads at same time).

    If you assume 4 hours of sun minimum in typical sunny weather, the average minimum amount of available power from the above arrays would be:
    • 705 Watt array * 0.52 end to end system eff * 4 hours minimum sun per day = 1,466 WH per day
    • 1,410 Watt array * 0.52 end to end system eff * 4 hours minimum sun per day = 2,933 WH per day
    • 1,833 Watt array * 0.52 end to end system eff * 4 hours minimum sun per day = 3,813 WH per day

    For a 184 AH @ 48 volt battery bank--The expected supported loads would be:
    • 184 AH * 48 volt * 0.85 inverter eff * 1/10 hour discharge = 571 Watts @ 230 VAC not to exceed (5 hour discharge on 2x load battery bank)
    • 184 AH * 48 volt * 0.85 inverter eff * 1/8 hour discharge = 938 Watts @ 230 VAC not to exceed (nominal maximum)
    • 184 AH * 48 volt * 0.85 inverter eff * 1/5 hour discharge = 1,504 Watts @ 230 VAC never to exceed (really pushing it)
    • 184 AH * 48 volt * 0.85 inverter eff * 1/2.5 hour discharge = 3,003 Watt 230 VAC max surge (starting load from pump, etc.)

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BadarBadar Solar Expert Posts: 38
    Re: And Now for a Petrol Pump

    Well, friend, I know I am much dumb in solar and electronics, but I believe I am not that dumb in mathematics. :D

    So if you can provide me with any link regarding this mathematics, I'll surely learn that.
    Still I believe max 3000 watts of panels will be enough.

    Since its sleep time here in Pakistan and next is working day, So I am going to sleep.
    Till then have a look at this calculator.

    http://forum.solar-electric.com/showthread.php?22448-PV-System-Estimation-Calculator&p=181306#post181306
  • BadarBadar Solar Expert Posts: 38
    Re: And Now for a Petrol Pump

    Thanks Bill, I am always happy to see your replies.

    I am happy that we have come closer to each other in term of sizing :D
    I will see how you calculated tomorrow.

    till then

    tata.

    take care
  • BB.BB. Super Moderators, Administrators Posts: 32,608 admin
    Re: And Now for a Petrol Pump

    Badar,

    It is not just the mathematics--It is the physical limitations (inverter ratings, actual limitations of battery bank, how much people wish to speed--up front vs over time, etc.)

    I am sure your mathematics is well above my capabilities.

    My suggestion--Is understand the requirements/capability of the battery bank--Then look at each load (group of loads) to see if the battery bank will support those needs.

    And same thing with each charging source too (not too big, not too small, just right:Goldilocks principle - Wikipedia)

    Then, understand the model as a whole--I.e., what do the batteries see/need when both loads and solar panels are operating during the middle of day together--Most of our "simplifications" assume that solar charging occurs during the day and most of the loads/discharging occurs when the sun is down). Mixed operation makes the modeling/estimating of needs/results much more complex and dependent on actual needs.

    Enough English Literature 101 for this post... Shall we now let Badar provide us an education in Urdu Literature? A solar power system is not a Zambeel (زمبیل ?):
    Meaning of Zambeel: The word Zambeel means a bag, but the word is more resonant of the mythical magical bag belonging to Amar Ayyar of the Amir Hamza tales. (Ammar Ayyar ki Zambeel). It’s magical quality gave it infinite possibilities of hiding and emerging anything in and from it. Click here to know more about the origin of the word : http://zambeeldramaticreadings.wordpress.com/posts/

    -Bill :D
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BadarBadar Solar Expert Posts: 38
    Re: And Now for a Petrol Pump
    BB. wrote: »
    I am sorry Badar... I need to read the posts much more closely than I am. :blush:


      -Bill

      Because the posts you are facing are lengthy and involves complications, and you are replying them in timely and detailed way, so its unavoidable.

      However you have lot of admiration in my town (my circle), and when I show them my threads and your(off course other members') detailed replies, they get surprised and ask me why these people spare their time for helping unknown people.

      Well, I respect all you people.
    • BadarBadar Solar Expert Posts: 38
      Re: And Now for a Petrol Pump
      BB. wrote: »
      Badar,


      Enough English Literature 101 for this post... Shall we now let Badar provide us an education in Urdu Literature? A solar power system is not a Zambeel (زمبیل ?):



      -Bill :D

      oooopsssss....I can understand what you are trying to suggest me by "Zambeel" metaphor. :D
      I am,actually, trying to think out of box. :D

      However now I am portraying myself in my mind, with long nose,long face, thin cheek, thin chin with long beard and a clown type long hat. Doing stupid things :s
      Attachment not found.

      However now Umroo Ayyar(Not Amar Ayyar) stories are being written only for children, Pakistan have newer version of Umroo Ayyar AKA "Ali Imran".
      A writer "Ibn-e-Safi" created this stupid, dumb looking but genius character in 1950s, eventually destroying enemy's plans. This new version of Umroo Ayyar gained wide popularity in Pakistan. "Ibn-e-Safi" died in 1978, but his character is still a living character.

      You would be surprised to know that in 1950s "Ibn-e-Safi" presented a terrorist organization, working in almost all countries of the world, planning to capture whole world.
      In his series of novels, he showed that this terrorist organization has almost captured Pakistan's tribal areas in the name of religion.
      And so is 2005s Pakistan ;)

      I think enough for literature, for today? :p
      umro.jpg 105.6K
    Sign In or Register to comment.