Nothing Special   »   [go: up one dir, main page]
Scribd Logo
Upload

Welcome to Scribd!

  • 14 views

    08 Exercises

    Uploaded by

    Zelda Urie
    Solar Exercises

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd

    08 Exercises

    Uploaded by

    Zelda Urie
    14 views9 pages
    Solar Exercises

    Original Title

    08_Exercises

    Copyright

    © © All Rights Reserved

    Available Formats

    PDF, TXT or read online from Scribd

    Did you find this document useful?

    Is this content inappropriate?

    Solar Exercises

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    14 views9 pages

    08 Exercises

    Uploaded by

    Zelda Urie
    Solar Exercises

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    You are on page 1of 9

    Grid-Tied Sizing Exercise

    Residential Installation:
    • The client has a North East facing tile roof (30deg East from North) – Size (12m x 7m).
    • Roof slope 25deg
    • Rafter spacing 700mm
    • Distance from roof to Solar DB is 20m
    • Average power consumption is 27kWh/day, R2025/Month Electricity Bill @ R2.5/kWh
    • Average night time power usage is 9kWh/night
    • Estimate peak load is 6kW
    • Available Solar Module: JA Solar 380W

    Calculations:
    Step1: Calculate annual daytime consumption: (27 kWh – 9 kWh) * 365 = 6570 kWh/a (*A)
    Step2: Using PVGIS(https://re.jrc.ec.europa.eu/pvg_tools/en/tools.html#PVP)
    Roof Angle: 25deg
    Result – Yield based on PVGIS per annum: 1624 kWh/kWp/a

    𝐴𝑛𝑛𝑢𝑎𝑙 𝐶𝑜𝑛𝑠𝑢𝑚𝑝𝑡𝑖𝑜𝑛 6570


    Step3: Required Size = = = 4.04 kWp
    𝑃𝑉𝐺𝐼𝑆 𝑆𝑝𝑒𝑐𝑖𝑓𝑖𝑐 𝑌𝑖𝑒𝑙𝑑 1624

    Step4: Calculate solar modules count needed


    4040
    = = 10.63 = 11 rounded up
    380

    Step5: Final Module Selection: 11 x 380W = 4.18 kWp

    Inverter Selection - Solis: Ppv = 4.18 kWp from Step5. (*B)

    INVERTER AC Rating Within Spec (Y/N)


    S6-GRIP2.5K 2500 N
    S6-GRIP3K 3000 N
    S6-GRIP3.6K 3600 N
    S6-GRIP4K 4000 Almost, might work
    S6-GRIP4.6K 4600 Y
    S6-GRIP5K 5000 Y
    S6-GRIP6K 6000 Y

    Selection:
    S6-GRIP4.6K

    String Design:
    Inverter MPPT voltage range: 90-520 V, DO NOT DESIGN FOR MAX. INPUT VOLTAGE!!!!
    Inverter Start Voltage: 120 V
    Number of MPPT: 2
    Max MPPT Current: 14 A / 14 A

    Module Power: 380 W


    Module Voc: 41.62 V
    Module Vmp: 34.77 V
    Module Imp: 10.93 A
    Module Temp. Coefficient (β_Voc): -0.272%/ °C
    Verify String Voltages:
    Using the above information adjust module for extreme temperatures between -5°C and 80°C.
    Parameters -5°C STC (25°C) 80°C
    Voc 45.02 V 41.62 V -
    Vmp - 34.77 V 29.57 V

    Voc (-5°C): Voc(STC) + [(Voc(STC) * β_Voc * ΔT) / 100] where ΔT = [-5 - 25]
    = 41.62 + [(41.62 * -0.272 * -30)/100]
    = 45.02 V
    Vmp (80°C): Vmp(STC) + [(Vmp(STC) * β_Voc * ΔT) / 100] where ΔT = [80 - 25]
    = 34.77 + [(34.77 * -0.272 * 55)/100]
    = 29.57 V

    𝑀𝑃𝑃𝑇 max 𝑣𝑜𝑙𝑡𝑎𝑔𝑒 520


    Inverter Max PV Modules: = = 11.55 = 11 Modules (rounded down
    𝑉𝑜𝑐 (−5°𝐶) 45.02
    not up!)
    𝑀𝑃𝑃𝑇 min 𝑣𝑜𝑙𝑡𝑎𝑔𝑒 90
    Inverter Min PV Modules: = = 3.04 = 4 Modules (rounded up not
    𝑉𝑚𝑝 (80°𝐶) 29.57
    down!)

    Voc (String-5°C): 11 modules x 45.02 V = 495.22 V (*C) – 1x MPPT required


    What if we used 12 modules in stead of 11 modules??
    Voc (String-5°C): 12 modules x 45.02 V = 540.24 V – 2x MPPT’s required as we are
    overvolting on 1 MPPT – (540.24 V > 520 V).
    Verify String Currents:
    Irradiation at client location assumption: 1200 W/m2
    𝑀𝑎𝑥 𝐼𝑟𝑟𝑎𝑑𝑖𝑎𝑡𝑖𝑜𝑛 1200
    IMPP MAX = × 𝐼𝑀𝑃𝑃 = × 10.93 = 13.12 A < 14 A
    𝑆𝑇𝐶 1000

    IMPP MAX is less than “Inverter Max MPPT Current”

    Cable Sizing:
    𝐶𝑎𝑏𝑙𝑒 𝐿𝑒𝑛𝑔𝑡ℎ×𝑆𝑡𝑟𝑖𝑛𝑔_𝑃𝑜𝑤𝑒𝑟
    𝐴= where Kcu = 58.7 m/Ω.mm2
    0.01×𝑉 2 ×𝐾𝑐𝑢

    = ((20m * 2) * 4.18 kW) / (0.01 * 495.222 * 58.7)


    = 167200 / 143957.552 = 1.16 mm2
    Backup Sizing Exercise (24Hours)
    Residential Installation:
    • The client has a North East facing tile roof (30deg East from North) – Size (12m x 7m).
    • Roof slope 25deg
    • Rafter spacing 700mm
    • Distance from roof to Solar DB is 20m
    • Average power consumption is 27kWh/day , R2025/Month Electricity Bill @ R2.5/kWh
    • Average night time power usage is 9kWh/night – 12hours (6pm to 6am)
    • Estimate peak load is 6kW
    • Available Solar Module: JA Solar 535W

    Calculations:
    Step1: Calculate annual consumption: 27 kWh * 365 = 9855 kWh/a
    Step2: Using PVGIS(https://re.jrc.ec.europa.eu/pvg_tools/en/tools.html#PVP)
    Azimuth: -150
    Roof Angle: 25deg
    Result – Yield based on PVGIS per annum: 1624 kWh/kWp/a
    𝐴𝑛𝑛𝑢𝑎𝑙 𝐶𝑜𝑛𝑠𝑢𝑚𝑝𝑡𝑖𝑜𝑛 9855
    Step3: Required Size = = = 6.07 kWp
    𝑃𝑉𝐺𝐼𝑆 𝑆𝑝𝑒𝑐𝑖𝑓𝑖𝑐 𝑌𝑖𝑒𝑙𝑑 1624

    Step4: Calculate solar module count needed.


    𝑃𝑜𝑤𝑒𝑟 𝑅𝑒𝑞𝑢𝑖𝑟𝑒𝑑 6070 𝑊
    Module Count = = = 11.35 = 12 rounded up
    𝑃𝑎𝑛𝑒𝑙 𝑃𝑜𝑤𝑒𝑟 535 𝑊

    Step5: Final Module Selection: 12 x 535W = 6.42 kWp

    Inverter Selection - Sunsynk:


    Ppv = 6.42 kWp from Step5.

    INVERTER AC Rating MPPT Rating


    SUNSYNK-3.6K-SG01/03LP1 3600 W 4680 W
    SUNSYNK-5K-SG01/03LP1 5000 W 6500 W
    SUNSYNK-8K-SG01LP1 8000 W 10400 W

    Selection: SUNSYNK-8K-SG01LP1

    String Design:
    Inverter MPPT voltage range: 125-425 V, DO NOT DESIGN FOR MAX. INPUT VOLTAGE!!!!
    Inverter Start Voltage: 150 V
    Number of MPPT: 2
    Max MPPT Current: 22 A / 22 A

    Module Power: 535 W


    Module Voc: 49.45 V
    Module Vmp: 41.47 V
    Module Imp: 12.90 A
    Module Temp. Coefficient (β_Voc): -0.275%/ °C
    Verify String Voltages:
    Using the above information adjust module for extreme temperatures between -5°C and
    80°C.
    Parameters -5°C STC (25°C) 80°C
    Voc 53.53 V 49.45 V -
    Vmp - 41.47 V 35.20 V

    Voc (-5°C): Voc(STC) + [(Voc(STC) * β_Voc * ΔT) / 100] where ΔT = [-5 - 25]
    = 49.45 + [(49.45 * -0.275 * -30)/100]
    = 53.53 V
    Vmp (80°C): Vmp(STC) + [(Vmp(STC) * β_Voc * ΔT) / 100] where ΔT = [80 - 25]
    = 41.47 + [(41.47 * -0.275 * 55)/100]
    = 35.20 V

    𝑀𝑃𝑃𝑇 max 𝑣𝑜𝑙𝑡𝑎𝑔𝑒 425


    Inverter Max PV Modules: = = 7.94 = 7 Modules (rounded down
    𝑉𝑜𝑐 (−5°𝐶) 53.53
    not up!)
    𝑀𝑃𝑃𝑇 min 𝑣𝑜𝑙𝑡𝑎𝑔𝑒 125
    Inverter Min PV Modules: = = 3.55 = 4 Modules (rounded up not
    𝑉𝑚𝑝 (80°𝐶) 35.20
    down!)

    We need to use 2x MPPT channels as 12 Modules > Maximum 7 Modules per MPPT!
    Divide 12 Modules by a factor of 2 for two MPPT’s.
    Voc (String-5°C): (12/2) modules x 53.53 V = 321.18 V for 6 modules

    Verify String Currents:


    Irradiation at client location assumption: 1200 W/m2
    𝑀𝑎𝑥 𝐼𝑟𝑟𝑎𝑑𝑖𝑎𝑡𝑖𝑜𝑛 1200
    IMPP MAX = × 𝐼𝑀𝑃𝑃 = × 12.90 = 15.48 A < 22 A
    𝑆𝑇𝐶 1000

    IMPP MAX is less than “Inverter Max MPPT Current”

    Cable Sizing:
    𝐶𝑎𝑏𝑙𝑒 𝐿𝑒𝑛𝑔𝑡ℎ×𝑆𝑡𝑟𝑖𝑛𝑔_𝑃𝑜𝑤𝑒𝑟
    𝐴= where Kcu = 58.7 m/Ω.mm2
    0.01×𝑉 2 ×𝐾𝑐𝑢

    A = ((20m * 2) * 3.21 kW) / (0.01 * 321.182 * 58.7) = 128400 / 60553 = 2.12 mm2
    Battery Sizing for night time usage:
    Average night time power usage: 9 kWh, so we require at least a 9 kWh battery.
    Peak Load: 6 kW, so we require a battery that can supply peak load power.
    Battery Power Usable Continues QTY Total Total
    Rating Capacity Power Required Capacity Continues
    Power
    US2000C 0.5C 2280 Wh 1200 W 4 9120 Wh 4800 W
    US3000C 0.5C 3374 Wh 1776 W 3 10122 Wh 5328 W
    US5000 1.0C 4560 Wh 4800 W 2 9120 Wh 9600 W
    Kodak FL5.2 1.0C *4608 Wh 5120 W 2 9216 Wh 10240 W

    𝑁𝑜𝑚𝑖𝑛𝑎𝑙 𝑉𝑜𝑙𝑡𝑎𝑔𝑒 × 𝑁𝑜𝑚𝑖𝑛𝑎𝑙 𝐶𝑢𝑟𝑟𝑒𝑛𝑡


    *Kodak usable capacity = × 𝐷𝑜𝐷
    100
    51.2 𝑉 ×100 𝐴
    = × 90 = 4608 W
    100

    ***Note US5000 battery not available at Segen Solar, only the UP5000 which is a 0.5C
    Battery.
    𝑅𝑒𝑞𝑢𝑖𝑟𝑒𝑑 𝐶𝑎𝑝𝑎𝑐𝑖𝑡𝑦 9000
    QTY required = = = 3.945 = 4𝑥 𝑈𝑆2000𝐶 𝐵𝑎𝑡𝑡𝑒𝑟𝑖𝑒𝑠
    𝑈𝑠𝑎𝑏𝑙𝑒 𝐶𝑎𝑝𝑎𝑐𝑖𝑡𝑦 2280

    Battery selection: 2x US5000 or 2x Kodak FL5.2

    Fuse and Breaker Selection:


    We need to protect the wires in both AC and DC applications.
    Select fuse and breaker size at least 0.8 * Wire rated current, but to be safe 0.5 * Wire rated
    current.
    Selected fuse or breaker should also be at least 1.25 * Working current, for optimal
    operation.
    PV Fuse Selection: 1.25 * IMPP MAX = 1.25 * 15.48 A = 19.35A (20 A Fuse for closest)
    selection)
    Datasheet will normally also show maximum series fuse rating.
    Load Shedding Example:
    Above Customer does not require batteries for night time coverage but asked to be able to
    cover load shedding for at least 3 hours during the night with an average night time peak
    load of 0.9 kW.
    Calculate Battery Capacity required to run night time loads for 3 hours:
    3 ℎ𝑟𝑠
    Battery Capacity = × 9 𝑘𝑊ℎ = 2.25 𝑘𝑊ℎ 𝐵𝑎𝑡𝑡𝑒𝑟𝑦
    12 ℎ𝑟𝑠

    Battery selection: US2000C, 0.9 kW < 1.2kW Continues power


    What if night time peak load was 1.5 kW, will the above selected battery still be sufficient?
    No. Continues power available from battery would be too low, either select the US3000C
    or add an additional US2000C in parallel.

    Module Layout Portrait:

    Module Layout Landscape:


    System Considerations:
    In SA most current standards or guidelines do not cover special requirements for PV installations.
    Nevertheless, during planning and mounting of a PV System all basic requirements defined in the
    Occupational Health and Safety Act, the National Building Regulations and other current acts or
    standards must be considered. The following list is not meant to be exhaustive as standards and
    regulations may change
    PV-Modules
    IEC 61215 (crystall.) and IEC 61646 (thin film)
    IEC 61730 part1 and 2: Safety
    Inverter
    NRS-097-2-1
    NRS-097-2-3
    RPP Grid Code
    Standards for installation:
    SANS 10142-1
    Mounting systems
    SANS 10160 (Load assumption and structural design)

    You might also like