NABCEP Exam Prep Review for PV Installation & Tech Sales 

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Slides from the lecture presented April 10th, 2014 by Sarah Raymer, Director of Education and Training at SolPowerPeople- a solar training company.

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NABCEP Exam Prep Review for PV Installation & Tech Sales 

  1. 1. NABCEP Exam Prep Review for PV Installation & Tech Sales A Review of Need-to-Know Key Concepts for NABCEP Exams Sarah Raymer, AKA Ms. MOOC
  2. 2. Tips Timing is everything Get some sleep- what studies show about retention “Shake it off, Champ!”
  3. 3. Topics for today:  Online tools for site assessment  Performing "ball-park estimates”- the risks  Grid Direct VS. battery-based systems  Site Analysis: system layout and installation- component location, NEC requirements, & effects on performance and cost  Equipment selection- component matching and utility interconnection requirements
  4. 4. Resource will be provided:  Array string calculations: effects of temperature, inverter matching  Solar resource assessment: Azimuth, magnetic declination  Array sizing: by area, budget, energy demand  Online resources for solar resource assessment (Peak Sun Hours)  Determining useable roof area and attachment points required  Trigonometry : tilt angles, shading obstructions
  5. 5. #SolarMOOC Resources  Subject Matter Experts  #SolarMOOC Academy dropdown menu option is Subject Matter Experts  ARCHIVE: #SolarMOOC Academy dropdown menu  Most Recent Lessons2012 / 2013 Archive
  6. 6. Online tools for site assessment  Google Earth - ruler and Azimuth tool  Google Maps -  “Classic maps” - ruler for rough estimate on sizing under “Maps Labs”  LIMITATIONS of tools and virtual assessment  Trees grow  Roof - hard to determine age / structural integrity  Can not see obstructions - vents/pipes  Can not achieve true shading analysis
  7. 7. Online tools for site assessment  NREL PV Watts Calculator - multiple versions  Solar resource  Performance estimate  ROI  Google it: ”PV WATTS”  Other professional proposal software will calculate more accurate costs and ROI specific to the customer  Ex. Rebates from utility & financing (effects ROI)  Ex. Of programs- Energy Periscope, OnGrid Solar
  8. 8. Google Earth • Measure lines, save for later viewing and sharing • Measure azimuth degrees instantly, declination preconfigured
  9. 9. Google- ruler tool and street view • Measurements • Azimuths • Roof pitch • Building height
  10. 10. PVWATTS from NREL FREE online tool NREL's PVWatts calculator determines the energy production and cost savings of grid-connected PV Systems.
  11. 11. Select your location... & click "send to PVWatts". Tweek a few things, click to calculate, and viola!
  12. 12. PV Watts Version 4 BETA
  13. 13. Site Analysis: Solar resource and shading  RESOURCES  NREL - Data tables (PSH)  Trig for shading analysis-  Go to solpowerpeople.com  Search for “trigonometry”:
  14. 14. Site Analysis: Solar resource and shading  Resources:  Azimuth - production, shading  Altitude - production, shading  Solar window - year round production assessment  Magnetic declination - accurate production and shading Site assessment fundamentals
  15. 15. Performing "ball-park estimates"- the risks  Online calculated area is not an accurate calculation of system size potential  Must visit site-  Obstructions  Shade  Mechanical considerations- roof trusses  Area efficiency not same as module efficiency  Power (kW), Area (m2), Efficiency  DC vs. AC
  16. 16. Performing "ball-park estimates"- the risks  Costs may change depending on site specific conditions  Roof mount - type and age  Pole or Ground mount - soil- rock?  Roof tilt - not easy to determine online  Be sure customer is aware of utility charges when considering expected bills  Return on Investment (ROI)  Utility buyback policies
  17. 17. Performing "ball-park estimates"- the risks  Resources:  #SolarMOOC Subject Matter Experts page:  Determine required attachments  Determine # of modules that will fit in area  Area, Budget and Energy demand sizing estimates Ball park estimates
  18. 18. Grid Direct VS. battery-based systems  Grid direct- requires anti islanding  DOES NOT function when grid is down  Net-metering/ dual metering potential  Grid offers “free storage”  More efficient than batteries  Inverter selection
  19. 19.  Battery based / Battery back-up  Stand Alone - will function when grid is down if storage exists  Grid tied with Battery Back-up- Critical load panel will function when grid is down-  limited capacity depending on battery bank size (autonomy)  More reliable = more storage = more expensive  Inverter selection, additional components  Conductors, OCPDs, charge controller, batteries, critical load panel, extra inverter if AC Coupled (battery backup)  NEC 690 Part VIII - Storage Batteries  NEC 480 - Storage Batteries Grid Direct VS. battery-based systems
  20. 20. Battery-based systems
  21. 21. Site Assessment: Layout & Install  Component location  NEC requirements  Effects on performance and cost 2011 NEC
  22. 22. Component Location & NEC Requirements  Installed in neat and workmanlike manner - NEC 110.12  Installed as listed or labeled - NEC 110.3(B)  Spaces required - NEC 110.26  Depends on location, voltage, etc.
  23. 23. Component Location  MODULES:  IFC regulations - becoming a standard  Not mandated in 2012 NEC  Look for it in 2014  Attachments - framing considerations (roof)  Shading - again and again
  24. 24. Inverter Location  Inverter - Distance from load center  Locate inverter near installation to avoid voltage drop  Potential shut down (design for inverter voltage range)  Prevent extra installation costs  Power loss, reduced ROI  Conductors  Conduit runs  Expansion fittings  Design time  Labor time  Chosen to match electrical connection
  25. 25.  Component functionality/treatment:  Out of sun  Consider temperature  Requirements for equipment installation  NEC 110.13 - mounting and cooling  NEC 110.12 - neat and workmanlike  NEC 110.26 - working spaces  NEC 110.27 - live parts  Equipment manual - NEC 110.3(B)  Installed as listed and labeled Inverter Location
  26. 26. Component Selection / Location Resources  Resources:  Voltage drop - #SolarMOOC with Raymer and Stovall  String sizing: Jeff Gilbert #SolarMOOC  Verifying System Design- voltage considerations, inverter matching, string sizing
  27. 27. Component Selection / Location  DC rated- NEC 690.4(D)  Disconnects, OCPDs  Disconnecting means- NEC 690 Part III  DC disconnect must be in an accessible location  AHJ may require additional external DC disconnect even if integrated into Inverter  AC modules/microinverters: NEC 690.6  Batteries: NEC Article 480 & Article 690 Part VIII  NEC 480.9: Battery locations (NEC 110)  NEC 480.8: Racks and trays  NEC 690.71(B): dwellings = <50V Nominal  NEC 690.71(D): Nonconductive racks
  28. 28. Effects on Performance and Cost  Performance  SHADE!- needs to be taken seriously- a tiny amount could kill production, and ROI for customer  Consider microinverters for potential solution  Geographical site considerations for production- smog, elevation, & Peak Sun Hours  High temperatures effect voltage (lowers)  High temperatures can effect equipment  Costs  Roof type and tilt or soil determines ease of installation  Requirements of interconnection- may require electrical upgrade
  29. 29. Equipment selection: component matching  Grid Direct Systems:  Inverter to Voltage (string design of array)  Match the inverter voltage window  Start voltage  Max of inverter as well as 600V DC limit per NEC code  Consider MPPT range
  30. 30. Equipment selection: component matching  Grid Direct Systems:  Inverter to Voltage (string design of array)  Match the inverter voltage window  Start voltage  Max of inverter as well as 600V DC limit per NEC code  Consider MPPT range  Conductor chosen for ampacity and conditions  Mike Holt- Verifying System Design
  31. 31. Other BOS components…  Conduit and conductors chosen for conditions and NEC requirements  Ex.: NEC requires metal conduit for DC conductors run inside of a building - NEC 690.31(E)  Ex.: PV Source conductors must be USE-2 or PV wire- NEC 690.31(B)  All equipment must be DC rated (unless dealing with AC modules/microinverters)
  32. 32. Component Selection: utility interconnection requirements  Make sure panel is not overloaded  NEC705.12(A) - Supply side connections possible  Treated as service connections- reference to NEC 230  NEC 705.12(D)(5) - Circuit breakers must be “suitable for backfeed” - if marked line and load, not suitable for load side connection
  33. 33. Component Selection: utility interconnection requirements  NEC 705.12(D) - Utility Interactive inverters  NEC 705.12(D)(2) - load side connection- 120% rule allowed  Sum of amp rating of OCPDs connected must not exceed 120% of rating of busbar  Ex. 200A bus bar x 1.2 = allowable 240A OCPDs  240A - 170A = 70A  170A in use, then max load side connection is 70A  Exception - with battery bank- can use inverter output current:  Ex. 30A output from inverter = 30 x 1.25 = 37.5A, 40A OCPD
  34. 34. Component Selection: utility interconnection requirements  Resource:  http://solarprofessional.com/articles/design- installation/nec-section-70512-and-utility- interconnections  Google: Supply side connection PV, or search SolarPro
  35. 35. Component Selection: utility interconnection requirements  120% rule: #SolarMOOC w/ Richard Stovall, SolPowerPeople CEO and IREC Certified Master Trainer
  36. 36. A favorite resource
  37. 37. Who are we, and who am I?  SolPowerPeople, Inc.  IREC Accredited Continuing Education Provider  Offering Solar Training, in person and online  Sarah Raymer  Director of Education and Training  Asst. Instructor, #SolarMOOC host  NABCEP Certified PV Installation Professional  sraymer@solpowerpeople.com

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