ELTR 1223 Survey of Renewable Energy Technology PV Power System Sizing and Configuration Unit 7 Source:

Use Policy  This material was developed by Timothy J. Wilhelm, P.E., Kankakee Community College, with funding from the National Science Foundation as part of ATE Grant No  All materials in this presentation are designed and intended for educational use, only. They may not be used for any publication or commercial purposes. Source:

Author, Editors/Reviewers  Author: Timothy J. Wilhelm, P.E., Kankakee Community College  Editors/Reviewers / Modifier:  Chris Miller Heartland Community College Source:

Objectives  Students will be able to describe, in very simple terms, at least three differences ( hardware differences and/or operational differences) between a pure grid-tied solar-PV system and a stand-alone solar-PV system.  Students will be able to list, and briefly describe (in very simple terms), the basic steps for sizing a stand-alone solar-PV power system. Source:

Objectives  Students will be able to describe, in very simple terms, the general construction of a pure grid- tied solar-PV power system, listing its basic components.  Students will be able to describe, in very simple terms, electric motor effect and electric generator effect. Source:

Objectives  Students will be able to describe, in very simple terms, how motor effect creates back-torque in an electric generator. Source:

Simple Utility-Tied System Source:

Utility-Tied PV  System is very simple, with few components.  System is sized almost strictly by budget. “How much can you afford to buy?”  System is modular and expandable in building-block- increments.  System does NOT provide back-up power when utility shuts down.  Can be configured to provide back-up power; but, involves additional equipment and more expense.  PV voltage approaches 600VDC!

Utility-Tied PV Parts and Pieces  PV Modules and interconnect wiring.  Racks for mounting PV array.  Combiner boxes for parallel connection of series strings of PV modules.  GFP for roof-mounted, residential arrays.  Grid-tie inverter.  Lockable, outside disconnect.  Properly sized bi-directional breaker in distribution panel.

PV Modules

PV Module Interconnects Source: t/wiring/blue_unconnected.jpeg

PV Mounting Racks Ballasted Pans for Flat Roof

PV Mounting Racks Fixed Racks for Pitched Roof

PV String Combiner Box

Grid-Tie Inverters Source: verters/gt3/Xantrex_grid_tie.jpg Source: MA3000_Prod_sb3000us_md_ x174.jpg

Grid-Tie Inverters, Lockable AC Disconnect

Inverter Output to Main Panel Lockable Disconnect!

Simple Stand-Alone System Source:

Stand-Alone PV  System is more complex and more expensive than pure grid-tie.  System is sized by load analysis.  System is modular and expandable in building-block- increments.  System IS back-up power when utility not available.  Requires monitoring and battery maintenance.  You must operate within your ENERGY budget.  PV voltage typically 12VDC, 24VDC or 48VDC, nominal.

Stand-Alone PV -- Parts and Pieces  PV Modules and interconnect wiring.  Racks for mounting PV array.  Combiner boxes for parallel connection of series strings of PV modules.  GFP for roof-mounted, residential arrays.  PV Charge Controllers.  Batteries.  Inverter/Charger.  Load Center.  Disconnects and OCP, everywhere.

PV Charge Controllers Source: /images/uploads/xw jpg Source: 349_Image1__TN180x200.jpg?6996 Source: utbackmx60Controller.gif

Batteries  Lead Acid Cells are Standard  Flooded cell  Gel Cell SMF  AGM SMF

Batteries Source: for-girls.com/images/6-volt-golf-cart- battery-Trojan-T-105.jpg Source: Source: ges/pv-concorde-battery-d.gif

Inverter/Chargers Source: om/images/products/VFX3648.jpg Source:

Put the pieces together… Source:

Sizing a Stand-Alone System  See In-Class Worksheet  Do you have proper solar access?  Do your load analysis.  Size your battery – days of autonomy.  Size your PV array – recharge in a day (or two, max.)  Size system for worst-case conditions!

Grid-Tied with Batteries Source:

Final Notes  Illinois now has mandatory net-metering!  If you have utility available, USE IT!  30% investment tax credit for next 8 years!  50% grants/rebates available from State (maybe)!  Production tax credit?

Let the Sun Shine!