solar schoolhouse and san mateo college designing and installing solar electric systems types of...
TRANSCRIPT
Solar Schoolhouse and San Mateo CollegeDesigning and Installing Solar Electric Systems
Types of Solar Electric SystemsFor Technology Teachers
San Mateo CollegeMay 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 DisconnectAnd toMeter
Subpanel
Solar AC in fromInverter
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 ModuleBatteryLoad
Stand Alone Residential System
Solar Array
Charge Controller
Battery
DC to AC Inverter
Distribution PanelAC
Distribution PanelDC
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 SM55220 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 ProtectionMust 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: Turns 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
InverterDistribution
Panel
ChargeControl
Battery
Utility