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. 0802786.

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 gridtied 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: http://www.rhoduselectric.com/images/10-14-08/Solar_Electric_Systems.jpg
Utility-Tied PV
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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-blockincrements.
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
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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:
http://www.mrsolar.com/Merchant2/graphics/produc
t/wiring/blue_unconnected.jpeg
PV Mounting Racks
Ballasted Pans for Flat Roof
PV Mounting Racks
Fixed Racks for Pitched Roof
PV Mounting Racks
Fixed Racks for Pitched Roof
PV Mounting Racks
Fixed Racks for Pitched Roof
PV String Combiner
Box
Grid-Tie Inverters
Source:
http://www.altestore.com/store/descfiles/xantrex/in
verters/gt3/Xantrex_grid_tie.jpg
Source:
http://hitechplumbingcorp.com/sitebuilder/images/S
MA3000_Prod_sb3000us_md_20070727112949167x174.jpg
Grid-Tie Inverters, Lockable AC
Disconnect
Inverter Output to Main Panel
Lockable
Disconnect!
Simple Stand-Alone System
Source: http://homepower.com/images/basics/Basics_SolarElect_OffGridFlow.jpg
Stand-Alone PV
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System is more complex and more expensive than pure
grid-tie.
System is sized by load analysis.
System is modular and expandable in building-blockincrements.
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
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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:
http://www.exploroz.com/images/Articles/
349_Image1__TN180x200.jpg?6996
Source:
http://www.readymaderesources.com/cart
/images/uploads/xw60-150.jpg
Source:
http://www.enviroharvest.ca/images/O
utbackmx60Controller.gif
Batteries

Lead Acid Cells are Standard

Flooded cell
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Gel Cell SMF
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AGM SMF
Batteries
Source:
http://shop.solardirect.com/ima
ges/pv-concorde-battery-d.gif
Source: http://www.electric-cars-arefor-girls.com/images/6-volt-golf-cartbattery-Trojan-T-105.jpg
Source:
http://suntolight.com/imagenes/productos/S24SLD.jpg
Inverter/Chargers
Source:
http://www.alternativeenergydiscounthouse.c
om/images/products/VFX3648.jpg
Source: http://www.msmelectric.com/mediac/400_0/media/Xantrex_SW.JPG
Put the pieces together…
Source: http://img.diytrade.com/cdimg/476964/2901505/0/1162516202.jpg
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: http://homepower.com/images/basics/Basics_SolarElect_GridBBFlow.jpg
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!