2. WHY SOLAR POWER?
• The world is depleting fossil fuel rapidly
• Global warming
• Renewable energy (PV)
• Each day earth receives 174 solar
Petawatts
• Solar PV price drops rapidly
3. OBJECTIVES
• View of most common PV systems
• Understanding of what are available
• Key Design and Installation
• Basic sizing calculation
• Cost estimate
4. 2 COMMON PV SYSTEMS
• GRID CONNECTED WITHOUT BATTERY
BACKUP
• GRID CONNECTED WITH BATTERY
BACKUP
6. SYSTEM CHARACTERISTICS
Without Battery
• PV arrays
• Combiner
• Inverter
With Battery
• PV arrays
• Combiner
• Inverter (ATS)
• Battery control
• Battery bank
• Critical Panel
7. SYSTEM CHARACTERISTICS
• GRID CONNECTED WITH BATTERY BACKUP
– Critical loads must be known a priory to size battery
(Which loads? How critical? How long?)
– Battery provide limited coverage period
– System complex and expensive
• GRID CONNECTED WITHOUT BATTERY
– Much common and most cost effective
– Shaving Peak Time
– Grid is down, PV system shuts down
– Virtual battery
8. NOMENCLATURES
Cells Semiconductor device that converts sunlight to DC current
(0.5 volt). It is the building block of the PV system.
Module A group of cells packed together in a safe environment with
easy connection and produce useful voltage and current.
Panels Include more PV modules assembled as a pre-wired,
field-installable unit.
Arrays Is a complete power-generating unit, consisting any number
of PV modules and panels
9. PV HISTORY
• 1839 – French scientist (Edmond Bacquerel) discovers
PV effect.
• 1923 – Albert Einstein received the Nobel Prize for his
photovoltaic theories.
• 1954 – Bell lab report 6% efficient of silicon cell
• 1958 – Vanguard I use solar power and it last 7 years.
• 1976 – Development of polycrystalline cell.
• 1980 – Introduction of Amorphous cells in the market.
• 1990 – Introduction of multilayer of thin film technology
• 2007 – world wide PV capacity reaches 2.8 GW
10. FACTS
• Solar cell material: Semiconductor Silicon
• Effective Spectrum: 0.3-0.6 micron
• Solar cell life: 20 years +
• Inverter life: 5 years
• Battery life: 5 years
• PV Efficiency: 14% (ideal), 10% (normal)
• Solar irradiance: 1000W/m2 (Standard Test Condition)
• PV panel (Thumb rules): 100W/m2, 10W/ft2
• Daily sun light: 4-10 hr per day (Win thru Su )
• Panel weight: 3-4 lbs/ft2
17. INSTALLATION
• Tilt angle facing South
– Flat mounted: lost up to 25% in efficiency
– Improves efficiency
– Tilt angle = Latitude ± Earth axis tilt (15 Deg)
– Improves cooling convection
– Cleaner surface (water & dirt runs off by gravity)
• Mount PV panels with standoff above existing structure
for cooling
• No shading or shadowing
23. SOLAR TRACKER
• Advantage:
– Best Efficiency: 25-40% with single axis.
– Single and dual axes
– When real estate and weight are at premium
– 1st application in Spacecraft such as satellites
• Disadvantage:
– High initial cost
– Maintenance cost
26. YOUR SYSTEM
• Grid connected
• Purpose: Power peak shaving
• 3-phase system (vs residential 1-phase)
• Fixed mount (no solar tracker)
• No battery backup
• During outage, the PV system shutdowns
27. DISCUSSION
• Solar irradiance is 4-6 times higher in
Summer than Winter (longer days & rays)
• Optimize the PV system for the Summer
(non tracker system)
• Tilt angle: (32 – 15) degree (San Diego)
facing south (summer optimized)
• Baseline level control
• Conservation 1st & Life Style
• Mixing modules in series is a no!