PV Cell -Working Principle and Applications by dsp14791

VIEWS: 283 PAGES: 9

									                                                How Powerful is Solar Power?
 PV Cell – Working Principle
                                               • Solar power intensity just outside the
     and Applications                            atmosphere of the Earth: 1.353 kW/m2.
                                                 This value is also called solar constant.
                                               • With the known radius of Earth ~=6380
                                                 km, solar power falling on The Earth
                                                 ~=173000TW
               1/Dec/2008
            Ir Dr Edward LO
                                               • While the current global power
                                                 consumption average over a year is only ~
           Associate Professor
                                                 16TW as in 2005
    Department of Electrical Engineering
   The Hong Kong Polytechnic University
                                           1                                             2




Solar power intensity ~ 1kW/m2 at
      sea level in sunny day




                                           3                                             4




 First application of PV cells                          How PV generates




                                           5                                             6




                                                                                             1
 Common Types of PV cells                         Different PV technology
                                                                           poly-crystalline /
                                                                           multi-crystalline (p-Si)
                                                                           typical efficiency: 10-15%


                                                mono-crystalline (m-Si)
                                                typical efficiency: 15%+


                                                                           Copper Indium Diselenide
                                                                           (CIS)
                                                                           typical efficiency: 9-12%


                                          Amorphous Silicon (a-Si)
                                      7   typical efficiency: 4-7%                                           8




     crystalline PV cells                         Semi-transparent PV cells
          m-Si     p-Si     p-Si
          14.46%   12.62%   8.29%




     p-Si
     12.68%                 p-Si
                            13.66%


                                      9                                                                     10




                                           Typical I-V & P-V Curve of a PV
                                            Cell at a given solar irradiance
                                            I
                                                                                            Power
 Cell,
                                                             1000 W/m2
Module,
 Array



                                                                                                        V
                                     11                                                                     12




                                                                                                                 2
 Typical I-V Curve of a PV Cell at
                                                Electrical properties, I-V curve
different values of solar irradiance                                                 Load curve of maximum power point
  I                                              I
                                                                                STC MPP
           1000 W/m2                                          1000 W/m2                               resistive load
            800 W/m2                                           800 W/m2

            600 W/m2                                           600 W/m2

          400 W/m2                                         400 W/m2

                       200 W/m2                                           200 W/m2



                                   V                                                                              V
                                       13                                                                              14




Effect of cell temperature on the V-I          Name Plate Rating of a PV Panel
 Curve (at given solar irradiation)
                                            • It is the
                                              maximum
                                              power output
                                              at STC
                                              (Standard Test
                                              Condition)

                                            • Usually STC =
                                              1000 W/m2,
                                              25°C Panel
                                              Temperature

                                       15                                                                              16




                                                     Effect of partial shading on
      efficiency characteristics
                                                      performance of PV array
                                                                                          Very low output from
                                                                                          the PV system,
                                                                                          although
                                                                                          Only ¼ of the
                                                                                          modules are shaded

                                                                              100% irradiance




                                                                              10% irradiance
                                       17                                                                              18




                                                                                                                            3
                                        Must maintain 3/4
                                        full output from the    Bypass
                                        PV system, when ¼       Diodes
                                        of the modules are
                                        shaded
                                                                                                         Blocking
                                                                                                         Diodes
                                   100% irradiance




                                10% irradiance

                                                           19                                                        20




                 BIPV Building Integrated                                Barriers to BIPV application
 The Plus Points:
                    Photovoltaic System
• Act as other building functions other than
  generating electricity                                        The HK scenario:
• No harmful side effects
                                                                •   Relatively high capital cost of the PV panels.
• No moving parts – silent, solid state device
• No (low) maintenance
                                                                •   Module efficiency is still relatively low
• Modular format /non-intrusive                                 •   Little understanding of PV system design
• Versatile                                                     •   Less real experience of installations
     • Locations       Rural/Urban                              •   Incentives (in HK) not yet in place
     • Applications for stand alone applications
       – Water pump, Lighting, Desalination plants         21                                                        22




                               Why BIPV? (1)                                                 Why BIPV? (2)
• Replace conventional building materials –                      • May cover part of the electricity consumption of
  concept of “avoided cost”                                        the building.
• Does not require any extra land area                           • Can provide electricity during peak demand time
                                                                   times and thus reduce the utility's speak delivery
• Does not require any additional support or                       requirements.
  infrastructure installation                                    • May reduce transmission and distribution loss.

The above three points ⇒ small                                   These points reduce the electricity bills of the
 “incremental” cost for BIPV systems                               building and delay the need for construction of
                                                                   new power plants.
                                                           23                                                        24




                                                                                                                          4
                   Consumption Curve and
                        Generation Curve                                                         Why BIPV ? (3)
         P ow er
                                                                • Can provide an improved aesthetic
         consum ptio n                                            appearance in an innovative way.
         by a building
                                          P ow er               • Can integrated with maintenance, control
                                          generation
         kW                               by P V pa nels          and operation of the other installations and
                                                                  systems in the building.
                                                                • Can provide reduced planning costs.

                            N oon
                         T im e o f day
                                                           25                                                                     26




                                                                   PV system: stand-alone vs.
                                    Why BIPV ? (4)
                                                                        grid-connected
• With grid connection, the system can
  totally eliminate the storage batteries and
  its associated problems.
• Hence lower capital, replacement and
  maintenance cost.




                                                           27                                                                     28




            Grid-connected systems
                                                                             Block diagram of G-BIPV
                          (G-BIPV)                                                                      from utility g rid

• PVs connected to the public grid via an                          Local loads

  inverter.                                                                      electromachanical safety
                                                                                        disconnect
• Eliminate the expensive and bulky
  batteries.
                                                                                  manual disconnect switch /
• Involve local regulatory issues.                                           electromachanical safety disconnect
                                                                                                                   AC
• Must compete against the cost of the
  conventional energy source used to supply                                                  Power conditioning subsystem
  the grid.                                                      PV arrays
                                                                                 DC     co-ordinated with the electromechanical
                                                                                              safety disconnect subsystem
                                                           29                                                                     30




                                                                                                                                       5
      Grid-connecting inverter                               New generation inverters (string
                                                                       inverter)
                                                                  100W



                               2kW
             2kW



                    convert DC to AC

                    capacity ranges from 100W to 500kW

                                                      31                                               32




  Characteristics of an inverter                                      inverter selection

                                                           • high efficiency (of course)
                                                           • selection of inverter nominal Pin with array's
                                                             rated kWp (e.g. vertical facade array)
                                                           • read the data-sheet carefully




                                                      33                                               34




                                                           Wanchai Tower of HK
 BIPV system at Wan Chai Tower                             Government Building –
                                                           3 BIPV Systems
• Three systems:
  – Rack type at the roof
  – Sun shading type at mid-floors
  – Skylight type at the lift lobby of ground floor

  The site: 22°16′50″N and 114°10′30″E
  Orientation: south facing about 5 degree off
   south toward east

                                                      35                                               36




                                                                                                              6
      Wan Chai Tower                                                            WanChai Tower: Roof
   Roof Rack BIPV System                                                       Polycrystalline 20 kWpeak
    Location                            Roof
    Orientation                         10 degree to horizontal,
                                        facing south
    Type of panels                      Polycrystalline
    No. of panels per string            18
    No. of strings                      7 strings per group, 2 groups
    Total no. of panels                 252
    Total PV panel area                 164.70 m2
    System rated power                  20.16 kW
    No. of inverters                    1 inverter per group
                                                                        37                                  38




     Wan Chai Tower                                                          WanChai Tower: Sun Shading
  Sun Shade BIPV System                                                             BIPV system
  Location                         Middle section of the
                                   building
  Orientation                      Vertically facing south
  Type of panels                   Monocrystalline
  No. of panels per string         21
  No. of strings                   8 strings per group, 2 groups
  Total no. of panels              336
  Total PV panel area              231.84 m2
  System rated power               20.16 kW
  No. of inverters                 1 inverter per group
                                                                        39                                  40




         Wan Chai Tower                                                      WanChai Tower: Skylight BIPV
       Skylight BIPV System                                                            system
Location                       Ground floor lobby
Orientation                    Vertically facing south
Type of panels                 Monocrystalline
No. of panels per string       5
No. of strings                 7 strings
Total no. of panels            35
Total PV panel area            95.98 m2
System rated power             10.08 kW
No. of inverters               1 inverter per group
                                                                        41                                  42




                                                                                                                 7
                       Sunny Day (21/5)                                                            A heavy rainy day (5/5)
1000          Gobal Irradiation                                                  16
              (W/m2)                                                                       500      Gobal Irradiation                                              10
  900                                                                                               (W/m2)
              Total Output Power                                                 14        450                                                                     9
  800                                                                                               Total Output Power
              (kW)                                                                         400      (kW)                                                           8
                                                                                 12
  700                                                                                      350                                                                     7
  600                                                                            10
                                                                                           300                                                                     6
  500                                                                            8         250                                                                     5
  400                                                                            6         200                                                                     4
  300                                                                                      150                                                                     3
                                                                                 4
  200                                                                                      100                                                                     2

  100                                                                            2          50                                                                     1
                                                                                             0                                                                      0
     0                                                                     0
                                                                                            4:48:00     7:12:00    9:36:00    12:00:00    14:24:00 16:48:00   19:12:00
    4:48:00        7:12:00     9:36:00    12:00:00 14:24:00 16:48:00 19:12:00
                        Blue line: left-axis   Pink line: right axis             43                         Blue line: left-axis   Pink line: right axis                 44




    Typical cloudy day, with scattered
                                                                                           Another typical cloudy day (24/5)
          “small clouds” (17/5)
     1200       Gobal Irradiation                                           25             1200       Gobal Irradiation                                            20
                (W/m2)                                                                                (W/m2)
                                                                                                                                                                   18
     1000       Total Output Power                                                         1000       Total Output Power
                (kW)                                                        20                        (kW)                                                         16
                                                                                                                                                                   14
        800                                                                                 800
                                                                            15                                                                                     12
        600                                                                                 600                                                                    10
                                                                            10                                                                                     8
        400                                                                                 400
                                                                                                                                                                   6

        200                                                                 5               200                                                                    4
                                                                                                                                                                   2
          0                                                                 0                  0                                                                0
         4:48:00     7:12:00    9:36:00    12:00:00 14:24:00 16:48:00 19:12:00                4:48:00    7:12:00    9:36:00    12:00:00 14:24:00 16:48:00 19:12:00

Blue line: left-axis Pink line: right axis Mean amount of cloud on that day: 87%45    Blue line: left-axis Pink line: right axis Mean amount of cloud on that day: 81%46
Total bright sunshine: 4.4 hr                                                         Total bright sunshine: 5.1 hr




   CCC Kei Wai School (Ma Wan)
        3 BIPV Systems
• 1.      28.8kW CIS
• 2.      4.0kW p-Si
• 3.      7.2kW a-Si




                                                     Type:PV /grid-connected
                                                     PVtechnology:CIS / p-Si / a-Si
                                                     PVnos:720+52+63=835
                                                     kWp= 40kW
                                                     AEY = ~49000kWh         47                                                                                          48
                                                     kWh/kWp:1225




                                                                                                                                                                              8
                                                  49                                                               50




 Science Park – 1 BIPV System




                    Type:PV /grid-connected
                    PVtechnology:m-Si
                    PV nos/area:1380 / 3019.8m2   51                                                               52
                    kWp= 198kW




                                                           Possible Talks from PolyU EE Dept:
                                                       •   Electricity – generation, transmission & distribution
• The End For This Part                                •   Renewable Energies
• Thanks for your attention                            •   Energy Efficiency
                                                       •   Intelligent Buildings
                                                       •   Electric Vehicles
                                                       •   LED Lighting and other new lighting systems
                                                       •   Power electronics & drives
                                                       •   Railway and its signaling systems
                                                       •   Application of photonic devices in engineering
                                                       •   Etc…..
                                                  53                                                               54




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