Residential Implementation of Photovoltaic
Systems
By
Chris Hinton & Patrick Patterson
Off-Grid & Grid Placement & System Sizing
Tied Orientation & Design
Mounting PV Modules
Techniques Energy
Storage
Future of PVs
Inverters Charge
controllers
Two Types of Residential
Photovoltaic (PV) Systems
• Off-grid • Grid-tied
Golden, Colorado East Lansing, Michigan
- National Renewable Energy Lab - National Renewable Energy Lab
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
Grid-tied PV Systems
Net Metering
Local incentives
promote grid-tied
systems exclusively
Reduce peak power
demand on utility - Energy Trust of Oregon
PV System Sizing
How much power do you need?
• Energy use & auditing
• Energy efficiency measures
• Energy requirements for PV
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
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
Module Placement & Orientation
Implications of shading
The sun path
Azimuth
Tilt angle
Moorepark, California
- BP Solar
Tracing the Sun
Seasonal sun path
- Real Goods
variations
Solar pathfinder tool
Obstacles to sunlight
can be traced and
predicted for different
times of the year
- Home Power Magazine # 57, pg. 32
Module Placement &
Orientation Guidelines
Standard PV module azimuth rule:
(Orientation) = (True South)
Note: In Portland, true South is about
19° east of magnetic South
http://www.proaxis.com/~johnbe
ll/iitt/questionftf49.htm
Standard PV module tilt rule:
(Angle from horizontal) =
(Geographic Latitude)
- Real Goods
What About Azimuth & Performance?
-Home Power Magazine # 93, pgs. 24-28
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
How much does tilt angle really matter?
-Home Power Magazine # 93, pgs. 24-28
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
Aesthetics Count
This is the same house!
-Home Power Magazine # 93, pg. 26 -Home Power Magazine # 93, pgs. 10, 11
Module Mounting
Roof Mounted
Ground Mounted
-Home Power Magazine
# 93, pg. 15
- National Renewable Energy Lab
Trackers
-Home Power Magazine # 95, pg. 127
Mounting Considerations
PV cooling
Wind resistance
Structural Stability
Code compliance
PV Orientation
Oak Park, California
Aesthetics - BP Solar
Visibility (visible installations may increase
public awareness of renewable energy)
Energy Storage
Off-grid storage needs
Grid-tied energy storage
Cost and Efficiency Considerations
- Home Power Magazine # 27, pg. 34
- National Renewable Energy Lab
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)
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
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 XS12205 12-volt, 184 amp hour, AGM
battery was designed for backup and solar applications.”
$399 (list) or $179 (on sale)
http://www.partsonsale.com/xs12200.html
Photovoltaic Hardware Selection
PV Modules
Inverters & Charge
Controllers
Mounting Hardware
Balance of System
Components
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
Module Comparison Chart
Photovoltaic Modules – Product
Survey
BP Solar: BP 5170
http://www.bpsolar.com/ContentDocuments/84/BP%205170S.pdf
Shell Solar: SP150-PC
http://www.shell.com/static/shellsolar/downloads/products/us/ShellSP150-PC_USv1.pdf
Evergreen Solar: EC-110
http://www.evergreensolar.com/egsolar1/pdf/ec100series13.pdf
Kyocera: KC120-1
http://www.kyocerasolar.com/pdf/specsheets/kc120_1.pdf
Sharp: NT-S5E1U
http://www.sharpusa.com/files/sol_dow_185WSS.pdf
Inverters – Selection Criteria
Output types
True sine wave
Modified sine wave
Input requirements
12VDC, 24VDC, 48VDC
String inverters
PV Modules wired accordingly
- SMA America
Monitoring and data logging capabilities
Non-islanding inverters for Grid-tie applications
Charge Controllers
Purpose – safe battery
charging
Types
Series
Shunt
Stand-alone units
Integrated (into inverter)
- RV Power Products
Inverter Comparison Chart
Remote Monitoring Options
PC Interface:
Trace (Xantrex)
-Home Power Magazine # 94, pgs. 24, 26
PC Interface: SunnyBoy
- SMA America
Inverters & Charge Controllers –
Product Survey
Outback Power Systems
http://www.outbackpower.com/
SMA America
http://www.sma-america.com/
Xantrex
http://www.xantrex.com/products/index.asp
Mounting Hardware
Two Seas Mounting Structures
http://www.2seas.com/matrix_ground_roof_a_r.htm
Ground/Roof
Flush Mount
Multi-Tier
Low Profile
Unirac
http://www.unirac.com/
Large Array PV Module Mounting System - UniRac
Solarmount (ground/roof)
Tracker 200 (2-module tracking rack)
Balance of System Components
DC disconnects
AC Disconnects
Fuses/Breakers
Grounding hardware
Lightning Arrestors
Combiner Boxes
Case Studies
Off Grid Living
Grid-tied with batteries and monitoring
Off Grid PV & Wind Hybrid System
Grid-tied system with unbelievable payback
Off Grid Case Study:
Bisbee Family
– Home Power Magazine #92, pgs. 22-27
Grid-tied Case Study:
Simons Family
- Home Power Magazine # 94, pgs. 22-27
Off Grid Case Study:
Reising & McCoy Family
- Home Power Magazine #89, pgs. 10-19
Grid-tied Case Study:
Webster Family
- Home Power Magazine #95, pgs. 22-28
Grid-tied Case Study:
Webster Family
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
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. 22-23.
• 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. 10-18.
• 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. 10-19.
• 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. 32-37.
• 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. 22-27.
• 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. 22-28.
• Xantrex (2003). Products [Internet] Available from: [Accessed July 2003]
• Yewdall, Z. (2003) PV Orientation. Home Power Magazine, No 93, February/March, pp. 24-28.