1. Residential Implementation of Photovoltaic Systems By Chris Hinton & Patrick Patterson
Off-Grid & Grid Tied
Mounting Techniques
Inverters
System Sizing & Design
PV Modules
Future of PVs
Placement & Orientation
Energy Storage
Charge controllers

2. Two Types of Residential Photovoltaic (PV) Systems
Grid-tied
Off-grid
Golden, Colorado
- National Renewable Energy Lab
East Lansing, Michigan
- National Renewable Energy Lab

3. Off-grid PV Systems Power for remote systems
Cost-prohibitive utility line extensions
Location unknown
- SolarDepot.com
“…Electric company quoted US$7 a foot to bring in the utility line from about a mile away (about US$37,000).”
- Home Power Magazine #92 Pg 22

4. Grid-tied PV Systems Net Metering
Local incentives promote grid-tied systems exclusively
Reduce peak power demand on utility
- Energy Trust of Oregon

5. PV System Sizing How much power do you need? Energy use & auditing
Energy efficiency measures
Energy requirements for PV

6. Off-grid System Considerations
Design system to match load
Begin with precise load calculations
Reduce load requirements through efficiency measures
Estimate energy production potential from solar insolation data
Select PV hardware to match load requirements
- Xantrex

7. Grid-tied System Considerations
Design system economically
Examine previous power bills
Implement energy efficiency first
Estimate production potential from solar insolation data
Choose % of load to match
Select PV hardware for utility interconnection
- Xantrex

8. Module Placement & Orientation
Implications of shading
The sun path
Azimuth
Tilt angle
Moorepark, California
- BP Solar

9. Tracing the Sun Seasonal sun path variations Solar pathfinder tool
Obstacles to sunlight can be traced and predicted for different times of the year
- Real Goods
- Home Power Magazine # 57, pg. 32

10. Module Placement & Orientation Guidelines
Standard PV module azimuth rule:
(Orientation) = (True South)
Note: In Portland, true South is about
19° east of magnetic South
Standard PV module tilt rule:
(Angle from horizontal) =
(Geographic Latitude)
- Real Goods

11. What About Azimuth & Performance?
Home Power Magazine # 93, pgs

12. Effects of Tilting PV Modules
Maximize energy production by optimizing tilt angle
Seasonal adjustments can further maximize production capabilities
- Home Power Magazine # 57, pg. 35

13. How much does tilt angle really matter?
Home Power Magazine # 93, pgs

14. Module Placement & Orientation Considerations
Placement and orientation often depend upon system priority:
Off-grid systems should maximize energy production
Grid-tied systems often maximize aesthetics characteristics

15. Aesthetics Count This is the same house!
Home Power Magazine # 93, pg. 26
Home Power Magazine # 93, pgs. 10, 11

16. Module Mounting Roof Mounted Ground Mounted Trackers
Home Power Magazine # 93, pg. 15
- National Renewable Energy Lab
Trackers
Home Power Magazine # 95, pg. 127

17. Mounting Considerations
PV cooling
Wind resistance
Structural Stability
Code compliance
PV Orientation
Aesthetics
Visibility (visible installations may increase public awareness of renewable energy)
Oak Park, California
- BP Solar

18. Energy Storage Off-grid storage needs Grid-tied energy storage
Cost and Efficiency Considerations
- Home Power Magazine # 27, pg. 34
- National Renewable Energy Lab

19. Off-grid Energy Storage
Calculate storage requirements from:
Climate (periods of cloudy weather?)
Critical loads (what do you need to power?)
Capacity should last 4 – 21 days
Batteries should not be discharged more than 50% – 70% or battery life is shortened
Install batteries in safe, climate-controlled, ventilated location (not in your living room)

20. Grid-tied Energy Storage
Most Grid-tied systems do not use batteries
Rather the utility grid is treated as a 100% efficient, unlimited capacity battery (except during outages)
Batteries may be added for additional storage flexibility

21. Batteries: Cost & Efficiency Considerations
Batteries add significant cost to a PV system
Charging batteries significantly reduces system efficiency: 20% energy losses are typical during battery charging
“The Xantrex XS volt, 184 amp hour, AGM battery was designed for backup and solar applications.”
$399 (list) or $179 (on sale)

22. Photovoltaic Hardware Selection
PV Modules
Inverters & Charge Controllers
Mounting Hardware
Balance of System Components

23. Photovoltaic Modules – Selection Criteria
Cell types (in decreasing order of price and efficiency)
Monocrystalline
Polycrystalline
Amorphous (thin-film)
Performance
IV curves
Maximum power rating
efficiency
Aesthetics

24. Module Comparison Chart

25. Photovoltaic Modules – Product Survey
BP Solar: BP
Shell Solar: SP150-PC
Evergreen Solar: EC-110
Kyocera: KC
Sharp: NT-S5E1U

26. Inverters – Selection Criteria
Output types
True sine wave
Modified sine wave
Input requirements
12VDC, 24VDC, 48VDC
String inverters
PV Modules wired accordingly
Monitoring and data logging capabilities
Non-islanding inverters for Grid-tie applications
- SMA America

27. Charge Controllers Purpose – safe battery charging Types
Series
Shunt
Stand-alone units
Integrated (into inverter)
- RV Power Products

28. Inverter Comparison Chart

29. Remote Monitoring Options

30. PC Interface: Trace (Xantrex)
Home Power Magazine # 94, pgs. 24, 26

31. PC Interface: SunnyBoy
- SMA America

32. Inverters & Charge Controllers – Product Survey
Outback Power Systems
SMA America
Xantrex

33. Mounting Hardware Two Seas Mounting Structures Unirac Ground/Roof
Ground/Roof
Flush Mount
Multi-Tier
Low Profile
Unirac
Large Array PV Module Mounting System
Solarmount (ground/roof)
Tracker 200 (2-module tracking rack)
- UniRac

34. Balance of System Components
DC disconnects
AC Disconnects
Fuses/Breakers
Grounding hardware
Lightning Arrestors
Combiner Boxes

35. Case Studies Off Grid Living Grid-tied with batteries and monitoring
Off Grid PV & Wind Hybrid System
Grid-tied system with unbelievable payback

36. Off Grid Case Study: Bisbee Family – Home Power Magazine #92, pgs

37. Grid-tied Case Study: Simons Family - Home Power Magazine # 94, pgs

38. Off Grid Case Study: Reising & McCoy Family - Home Power Magazine #89, pgs. 10-19

39. Grid-tied Case Study: Webster Family - Home Power Magazine #95, pgs

40. Grid-tied Case Study: Webster Family

41. Conclusions & Personal Thoughts
Carefully designed residential PV systems provide their owners with clean, reliable power, and promote interest in renewable energy sources
Hydrogen as Energy Storage
Building-integrated materials
Expanded use of solar energy for water purification, water heating, space heating (air-to-air heat exchangers), as well as electricity production
Home Power Magazine # 93, pg. 27

42. References
Bell, John (2000). Questions from the Field… [Internet] Available from: < [Accessed July 2003]
Bisbee, D. (2002) Off the Grid: Starting Small Home Power Magazine, No 92, December/January, pp
BP Solar (2003). BP Solar Home Page [Internet] Available from: < [Accessed July 2003]
Chadderdon, M. and Chadderdon, J. (2003) The Chadderdon Photovoltaic Story. Home Power Magazine, No 93, February/March pp
Energy Trust (2003). Solar Electric for Homes and Businesses [Internet] Available from: < [Accessed July 2003]
McCoy, C. and Reising, C. (2002) Still Saying "Yes" to Sunshine Home Power Magazine, No 89, June/July, pp
National Renewable Energy Lab (2003). Photographic Information Exchange [Internet] Available from: < [Accessed July 2003]
OutBack Power Systems (2003). OutBack Power Systems Home Page [Internet] Available from: < [Accessed July 2003]
Perez, R. and Drake, J. (1997) Where and How to Mount PV Modules. Home Power Magazine, No 57, February/March, pp
RV Power Products (2003). RV Power Products Home Page [Internet] Available from: < [Accessed July 2003]
Schaeffer, J. ed. (2001) Solar Living Source Book: The Complete Guide To Renewable Energy Technologies & Sustainable Living. 11th ed. USA,
Chelsea Green Publishing Company.
Simons, B. (2003) PV Done Right - Grid Tie, Battery Backup, and System Monitoring. Home Power Magazine, No 94, April/May, pp
SMA-America (2003). SMA-America Home Page [Internet] Available from: < [Accessed July 2003]
Solar Depot (2003). Solar Depot Home Page [Internet] Available from: < [Accessed July 2003]
Solatron Technologies (2003). Xantrex XS12205 [Internet] Available from: < [Accessed July 2003]
Two Seas Metalworks (2003). Two Seas Metalworks Home Page [Internet] Available from: < [Accessed July 2003]
UniRac (2003). Unirac Home Page [Internet] Available from: < [Accessed July 2003]
Webster, D. (2003) Getting Off the Lifetime Utility Payment Plan. Home Power Magazine, No 95, June/July, pp
Xantrex (2003). Products [Internet] Available from: < [Accessed July 2003]
Yewdall, Z. (2003) PV Orientation. Home Power Magazine, No 93, February/March, pp