ELTR 1223Survey of Renewable

Energy Technology

PV Power System Sizing and Configuration

Unit 7

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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.

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Author, Editors/Reviewers Author: Timothy J. Wilhelm, P.E.,

Kankakee Community College Editors/Reviewers / Modifier: Chris Miller Heartland Community

College

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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.

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Objectives Students will be able to describe, in

very simple terms, how motor effect creates back-torque in an electric generator.

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Simple Utility-Tied System

Source: http://www.rhoduselectric.com/images/10-14-08/Solar_Electric_Systems.jpg

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 PVParts 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: http://www.mrsolar.com/Merchant2/graphics/product/wiring/blue_unconnected.jpeg

PV Mounting RacksBallasted Pans for Flat Roof

PV Mounting RacksFixed Racks for Pitched Roof

PV Mounting RacksFixed Racks for Pitched Roof

PV Mounting RacksFixed Racks for Pitched Roof

PV String Combiner Box

Grid-Tie Inverters

Source: http://www.altestore.com/store/descfiles/xantrex/inverters/gt3/Xantrex_grid_tie.jpg

Source: http://hitechplumbingcorp.com/sitebuilder/images/SMA3000_Prod_sb3000us_md_20070727112949-167x174.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 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: http://www.readymaderesources.com/cart/images/uploads/xw60-150.jpg

Source: http://www.exploroz.com/images/Articles/349_Image1__TN180x200.jpg?6996

Source: http://www.enviroharvest.ca/images/Outbackmx60Controller.gif

Batteries Lead Acid Cells are Standard

Flooded cell

Gel Cell SMF

AGM SMF

Batteries

Source: http://www.electric-cars-are-for-girls.com/images/6-volt-golf-cart-battery-Trojan-T-105.jpg

Source: http://suntolight.com/imagenes/productos/S24SLD.jpg

Source: http://shop.solardirect.com/images/pv-concorde-battery-d.gif

Inverter/Chargers

Source: http://www.alternativeenergydiscounthouse.com/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!