Solar Schoolhouse and San Mateo College Designing and Installing Solar Electric Systems Types of Solar Electric Systems For Technology Teachers San Mateo College May 17, 2008

Disclaimer This workshop does not certify you and Solar Schoolhouse and San Mateo College are not responsible for anything you do with this knowledge

Three Basic Types: Stand Alone Simple Grid Tied Grid Tie with Battery

Grid Tie Solar Electric Systems Quick View

Simple Grid-tie system (Utility intertie) Solar Array Inverter Distribution Panel Utility

Attaching Rack System To The Roof Mounting bracket bolted into rafter; rack then bolted to mount.

Series Wiring with MC Connectors

Conduit From Array to Disconnects

Simple Grid Tie with Two Inverters: Disconnects, Inverters, and Subpanel To PGE Disconnect And to Meter

Subpanel Solar AC in from Inverter Lightning surge arrestor AC from inverter to PG&E disconnect then back to breakers

Stand Alone Systems I.e. No Grid

SIMPLE: Load directly powered by solar photovoltaic module

With Storage: Solar Module Battery Load

Stand Alone Residential System Solar Array Charge Controller Battery DC to AC Inverter Distribution Panel AC Distribution Panel DC

Small Stand Alone System (to power an office) Solar Array Charge Control Storage: Battery Fuel Gauge Inverter DC to AC

Roof mount Solar Array: 4 SM Watts wired in parallel

Stand Alone System Components

Disconnect Between Solar Panel and the Battery (via Charge Control) Breakers and fuses must be DC rated. Can purchase special for PV application equipment. In this system we used Square D QO which is ok for DC up to 24 volts

Charge Control for Battery: note display and battery type selector

Storage: Battery: Flooded, Sealed, AGM, or Gel

Fuse: Circuit Protection Must be large enough to allow maximum designed current (+ x%) to flow through circuit and blow before wire overheats (maximum size determined by ampacity rating of wire).

Inverter: DC to AC Pure sine wave: T urns DC electricity of PVs and Batteries into AC current. DC in AC out

Wire Strategy Select wire sizes that minimize Voltage Drop: based on distance and current Select insulation types depending on where wire is located and whether or not it is in conduit. (UV, temperature, moisture) Be strategic in which voltage you use for system: depends on wattage and length of wire runs

Balance of System Inverter Charge Control Fuel Gauge Battery

Safety at Schools, etc Follow good wiring practice: keep unshielded wire out of the reach of people: in conduit, behind transparent barrier such as glass or lexan. Fusing, breakers, ground fault protection. DC lines must use DC rated equipment. Batteries must be inaccessible to unauthorized people…i.e. locked Use Adequate Mounts for Solar Panel

Larger Stand Alone Systems: 1 kw

Combiner Box

MX60 Charge Controller in Action

Grid Tie with Stand Alone Capability Solar Array Inverter Distribution Panel Charge Control Battery Utility