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Flashcards

NABCEP Entry Level Study Guide

Shea Poage Inglês 85 flashcards

Flashcards do conjunto (85)

  1. 1Solar radiationRadiant energy emitted by the sun
  2. 2Solar irradianceSolar radiation that has reached Earth's surface. Power per unit area produced by the Sun. W/m^2 Measure of how much solar power you are getting at your location.
  3. 3Solar irradiationSolar irradiance integrated over time. Wh/m^2
  4. 4Solar insolationThe amount of solar irradiation per day Wh/m^2/day
  5. 5Solar constantThe long-term average of the total solar irradiance. Quantifies the amount of radiation energy that arrives from the sun at the outermost layers of the atmosphere. 1.353 kW/m^2
  6. 6Air massThe path length which light takes through the atmosphere normalized to the shortest possible path length (when the sun is directly overhead). AM=1/cos(angle from the vertical). When sun is overhead, air mass=1.
  7. 7Ecliptic planePlane in which the Earth orbits the Sun
  8. 8Equatorial planePlane containing Earth's equator and extending outward into space
  9. 9PyranometerMeasures global radiation in an area. Measures both direct and diffuse (reflected) radiation
  10. 10Solar declinationAn angle between the equatorial plane and rays of the sun
  11. 11SolsticeWhen the sun will raise to either the highest or lowest path possible
  12. 12EquinoxThe sun will move across the sky for the same amount of time everywhere in the world
  13. 13Solar timeCorresponds with the sun's position in the sky. Noon solar time is when the sun is highest in the sky
  14. 14Solar altitude angleThe vertical angle between the sun and the horizon
  15. 15Solar azimuth angleThe horizontal angle between a reference direction (typically due south) and the sun
  16. 16Solar windowThe area between the path of the sun at summer solstice and the path of the sun at winter solstice.
  17. 17Array tilt angleThe vertical angle between horizontal and the array surface
  18. 18Array azimuth angleThe horizontal angle between a reference direction and the direction an array surface faces
  19. 19Solar incidence angleThe angle between the sun's rays and a line perpendicular to the array surface
  20. 20Energy equationEnergy=power x time
  21. 21V=volts, V=IR
  22. 22I=amps, current, amperes
  23. 23R=resistance, ohms
  24. 24W=watts, power
    W=VI
  25. 25Isc=short circuit current. When you have all current and no voltage (wires are crossed/shorted)
  26. 26Voc=Voltage Open Circuit. When you have all voltage and no current (wires not touching/open circuit)
  27. 27Imp=Current Maximum Power
  28. 28Vmp=Voltage Maximum Power
  29. 29Imp x Vmp =STC watts
  30. 30STCStandard Test Conditions. Irradiance at STC=1,000 watts/m^2. Temp is 25C. 1.5 atmosphere spectrum of light. Does not take heat from irradiance into account.
  31. 31MPPTM
  32. 32Wiring in series increases ________, wiring strings in parallel increases ________.voltage, current
  33. 33120% ruleBusbar * 1.2 must be greater than or equal to the main breaker + backfeed (solar) breaker
  34. 34Max current on PV source circuit=Isc * 1.25, because sometimes we can get 1,250 watts per m^2 of irradiance
  35. 35DC PV conductor sizingCompare Isc * 1.56 and Isc * 1.25 and conditions of use, then pick the biggest conductor of the two.
  36. 36What kind of wire is white?Grounded current carrying conductor, usually negative.
  37. 37What kind of wire is green or bare?Grounding and non-current carrying for grounding equipment for safety
  38. 38What kind of wire is black?Hot ungrounded current carrying conductor
  39. 39Wire sizesBigger wires have smaller numbers. Small wire=AWG 16, large=000
  40. 40Temperature correction factors for cold temperaturesTwo ways:
    -PV mfg (?) gives temp coefficient of Voc (ex: 0.33%/deg. C). Multiply by delta deg C from 25 C for increase Voc in cold temp
    -If no coefficient from mfg, use table 690.7 (?) and multiply Voc by temp factor (If record low temp =-40C, correction factor is 1.25. If 40 Voc module @ 0C, 40V*1.25=50 Voc
  41. 41Calculate circuit breaker size.Inverter output max current * 1.25=circuit breaker size (round up)
  42. 42Calculate battery sizing given days of autonomy and depth of discharge.If you use 10 kWh/day, 3 days of autonomy, 50% depth of discharge:
    10 kWh * 3 days = 30 kWh
    30 kWh / .5 depth of discharge = 60 kWh in battery bank
    Then derate for other things
  43. 43Peak sunjk
  44. 44Peak sun hoursjk
  45. 45Consequences of array shading and best practices for minimizing shading and preserving outputMinimizing shading: take 3 times height of modules b/t modules
    Distance between rows= height * cos(azimuth)/tan(altitude)
  46. 46Spacing distancesjk
  47. 47Five key electrical output parametersVoc: open circuit voltage
    Isc: short circuit current
    Vmp: max power voltage
    Imp: max power current
    Pmp: max power point
    Label on an I-V curve (current-voltage): Isc is high A, no V, Voc is high V, no A, and Imp and Vmp meet at the maximum power point.
  48. 48Performance rating and measurement conditionsSTC: 25 C, 1,000 w/m^2
    SOC: 1,000 w/m^2 & nom (NOCT) temp
    NOCT: 800 w/m^2, 20 C, wind speed 1 m/s
    PTC
  49. 49Overcurrent protectionjk
  50. 50Conduit and raceway systemsjk
  51. 51Switchgearjk
  52. 52Junction and combiner boxesCombiner boxes: overcurrent protection for modules and conductors. Combines series strings in parallel. Need one per series string, and it needs a DC disconnect
  53. 53Terminatorsjk
  54. 54Connectorsjk
  55. 55De-rating factors and system lossesjk
  56. 56Major components of a PV systemjk
  57. 57A fall protection system must be in place for all work done at heights in excess of _______.6 feet
  58. 58A circuit breaker performs the same function as ______.a fuse, a switch, and over-current protection
  59. 59What typically trips a breaker?Not voltage...need more info
  60. 60Between the main pane and the inverter, you have _______.an AC disconnect
  61. 61Between the array and the inverter, you have _______.2 of the following are correct: a DC disconnect, an AC disconnect, sometimes a charge controller
  62. 62KNOW HOW TO READ A SUN DIAGRAMok
  63. 632 phase is...what is it
  64. 64Utility interconnection is done in this order:PV, charge controller, battery, inverter, grid
  65. 65In California, magnetic North is pointing....?More east than true north, BECAUSE...?
  66. 66The critical design month is the worst case scenario where the load and the _______ are used to size the PV systeminsolation data
  67. 67If you combine solar and wind energy in an off-grid system, it is ______.hybrid
  68. 68Irradiance proportionally affectsamperage, NOT voltage
  69. 69The further north you are, the better it is toincrease your tilt angle (match the latitude)
  70. 70Temporarily shorting the output terminals of a PV module willhave no effect on the module
  71. 71KNOW HOW TO READ A SUN PATH DIAGRAMok
  72. 72When the sun sets on summer solstice, it is the farthest ______ that it will ever set.north
  73. 73The best way to increase your PV output is toswitch from stand alone to interactive (tracking?)
  74. 74What factor inhibits higher voltages in PV?hot weather
  75. 75Linear current boostersare commonly used in direct pumping applications and drop voltage
  76. 76Irradiance is measured inwatts per square meter
  77. 77The length of time a load is on...is proportional to the energy used
  78. 78Equinoxis the same day everywhere in the world at the same time
  79. 79Ideal altitude and azimuth orientations for PV arraysYear-round use:
    Summer only:
    Winter only:
  80. 80What is the rule of thumb for estimating daily and yearly output for a PV array?1,000 kW per installed kW per year
  81. 81Calculate the efficiency of a PV module.Efficiency=Pmp/solar irradiance * area (m^2)
  82. 82How to calculate appropriate distance between modulesDistance between modules = height of modules * cos(az angle between solar az and array az)/tan(sun altitude angle)
  83. 83Why is DC current more dangerous that AC?It is constant and more difficult to break
  84. 84Ideal angle (altitude) of collector =complimentary angle of sun chart's altitude
  85. 85Charge controllerPurpose is to prevent overcharging battery, prevent reverse current flow, protect equipment from high voltage.

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Descrição
A study guide for the NABCEP Entry Level exam.
Criado por
Shea Poage
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