Residential Implementation of Photovoltaic Systems By Chris Hinton

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

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

Off-grid PV Systems n Power for remote systems n Cost-prohibitive utility line extensions Location unknown - Solar. Depot. 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 n Net Metering n Local incentives promote grid-tied systems exclusively n 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 n Begin with precise load calculations n Reduce load requirements through efficiency measures n Estimate energy production potential from solar insolation data n Select PV hardware to match load requirements - Xantrex

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

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

Tracing the Sun n Seasonal sun path variations n Solar pathfinder tool n Obstacles to sunlight can be traced and predicted for different times of the year - Real Goods - 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 § Standard PV module tilt rule: (Angle from horizontal) = (Geographic Latitude) http: //www. proaxis. com/~johnb ell/iitt/questionftf 49. htm - 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: n Off-grid systems should maximize energy production n 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 n n n n PV cooling Wind resistance Structural Stability Code compliance PV Orientation Oak Park, California - BP Solar Aesthetics Visibility (visible installations may increase public awareness of renewable energy)

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

Off-grid Energy Storage n Calculate storage requirements from: n n n 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 n Install batteries in safe, climate-controlled, ventilated location (not in your living room) n

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

Batteries: Cost & Efficiency Considerations Batteries add significant cost to a PV system n Charging batteries significantly reduces system efficiency: 20% energy losses are typical during battery charging n “The Xantrex XS 12205 12 -volt, 184 amp hour, AGM battery was designed for backup and solar applications. ” $399 (list) or $179 (on sale) http: //www. partsonsale. com/xs 12200. html

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

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

Module Comparison Chart

Photovoltaic Modules – Product Survey n BP Solar: BP 5170 http: //www. bpsolar. com/Content. Documents/84/BP%205170 S. pdf n Shell Solar: SP 150 -PC http: //www. shell. com/static/shellsolar/downloads/products/us/Shell. SP 150 -PC_USv 1. pdf n Evergreen Solar: EC-110 http: //www. evergreensolar. com/egsolar 1/pdf/ec 100 series 13. pdf n Kyocera: KC 120 -1 http: //www. kyocerasolar. com/pdf/specsheets/kc 120_1. pdf n Sharp: NT-S 5 E 1 U http: //www. sharpusa. com/files/sol_dow_185 WSS. pdf

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

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

Inverter Comparison Chart

Remote Monitoring Options

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

PC Interface: Sunny. Boy - SMA America

Inverters & Charge Controllers – Product Survey n Outback n http: //www. outbackpower. com/ n SMA n Power Systems America http: //www. sma-america. com/ n Xantrex n http: //www. xantrex. com/products/index. asp

Mounting Hardware n Two Seas Mounting Structures http: //www. 2 seas. com/matrix_ground_roof_a_r. htm n n n Ground/Roof Flush Mount Multi-Tier Low Profile Unirac http: //www. unirac. com/ n n n Large Array PV Module Mounting System Solarmount (ground/roof) Tracker 200 (2 -module tracking rack) - Uni. Rac

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

Case Studies n Off Grid Living n Grid-tied with batteries and monitoring n Off Grid PV & Wind Hybrid System n 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 & Mc. Coy 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 n Carefully designed residential PV systems provide their owners with clean, reliable power, and promote interest in renewable energy sources n Hydrogen as Energy Storage n Building-integrated materials n 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: <http: //www. proaxis. com/~johnbell/iitt/questionftf 49. htm> [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: <http: //www. bpsolar. com> [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: <http: //www. energytrust. org> [Accessed July 2003] • Mc. Coy, 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: <http: //www. nrel. gov/data/pix. html> [Accessed July 2003] • Out. Back Power Systems (2003). Out. Back Power Systems Home Page [Internet] Available from: <http: //www. outbackpower. com> [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: <http: //www. rvpowerproducts. com> [Accessed July 2003] • Schaeffer, J. ed. (2001) Solar Living Source Book: The Complete Guide To Renewable Energy Technologies & Sustainable Living. 11 th 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: <http: //www. sma-america. com> [Accessed July 2003] • Solar Depot (2003). Solar Depot Home Page [Internet] Available from: <http: //www. solardepot. com> [Accessed July 2003] • Solatron Technologies (2003). Xantrex XS 12205 [Internet] Available from: <http: //www. partsonsale. com/xs 12200. html> [Accessed July 2003] • Two Seas Metalworks (2003). Two Seas Metalworks Home Page [Internet] Available from: <http: //www. 2 seas. com/matrix_ground_roof_a_r. htm> [Accessed July 2003] • Uni. Rac (2003). Unirac Home Page [Internet] Available from: <http: //www. unirac. com> [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: <http: //www. xantrex. com/Products/index. asp> [Accessed July 2003] • Yewdall, Z. (2003) PV Orientation. Home Power Magazine, No 93, February/March, pp. 24 -28.