Transcript RESPONSIVE DESIGN P RO C E S S

Solar Power Systems
Energy from the Sun
Solar Energy
Practical Uses of Solar Energy
Solar Water Heaters
Photovoltaic Development
Russell Ohl 1940
Edmund Becquerel 1839
Gerald Pearson, Daryl Chapin, and Calvin Fuller 1953
William Grylls Adams 1876
Space Race Saves PV
Vanguard I Satellite 1958 One Watt
Telstar Satellite 1962 14 Watts
From Novelty to Real World Applications
Buoys and Lighthouses
RR Crossings Rex, GA 1974
Offshore Oil Platforms
P-N Junction
Photovoltaic cell
Electrical Properties of a Solar Cell
Diode current
5
A(e BV -1)
Isc
External circuit
(e.g., battery,
lights)
–
V
+
Diode Amps
BV
AA((eeBV --11))
I
I  I sc - A(e
BV
0
- 1)
0.0
Diode Volts
0.6
I  I sc - A(e BV - 1) , where A, B, and especially Isc vary with solar insolation
I
Increasing
solar insolation
Isc
Maximum
power point
Im
Pmax  Vm I m
0
V
0
Vm
Voc
I – V Curves
Terms
• Solar Irradiance (density), average 1 kW per square meter
at noon on a clear day at sea level
• Solar Insolation: hours per day that solar panel delivers
rated voltage, varies seasonally
• STC: standard test conditions, 25° C, 1 kW per square
meter irradiance & AM 1.5
• AM: Air Mass, density & clarity of air sunlight passes
through to reach the modules
PV Panel Ratings
Nameplate (STC) Rating
Field Rating
The PV Cell & Panel Families
Polycrystalline Panel
Monocrystalline Panel
Thin Film Panel
PV Cells and Panel Assembly
Monocrystalline Panel
Polycrystalline Panel
Thin Film Panel
PV Basics
PV CELL OVERVIEW
SINGLE CRYSTALLINE
POLYCRYSTALLINE
CELL
STRING RIBBON
AMORPHOUS OR THIN
FILM
Typically dark blue in
color
Typically dark blue in
color
Typically dark blue in
color
Typically black in
color
Efficiency averages
10% to 12%
Efficiency averages
9% to 11%
Efficiency averages
10% to 11%
Efficiency averages
6% to 9%
Degradation averaging Degradation averaging Degradation averaging Degradation averaging
0.25% to 0.5% per
0.25% to 0.5% per
0.25% to 0.5% per
0.25% to 0.5% per
year
year
year
year
Vendors typically
Vendors typically
Vendors typically
Vendors typically
guarantee power 90% guarantee power 90% guarantee power 90% guarantee power 90%
for 10 years , 80% for for 10 years, 80% for for 10 years , 80% for for 10 years, 80% for
25 years
25 years
25 years
25 years
PV Panel Arrangements
• 36 Cells in Series Make a 12V-Class Panel (Voc  19V)
9 cells x 4 cells is a
common configuration
•Two 12V-Class Panels in Series Make a 24V-Class Array (Voc  38V)
• 60 Cells (5x12) in Series Make a 30.2V Nominal Panel (Voc  36.8V)
PV Systems
Utility Intertie
Stand alone direct connected
Stand alone PV System
Typical Grid Tie without Battery
20 panel 2.5 kW PV System Santa Rosa CA
TOU
Meter
DC Disconnect & Inverter
Metering Data
TOU rate 31¢/kwh Noon to 6PM (peak solar production); non-peak rate 11¢/kwh
Quantifying the Resource
Location, Location, Location
1.2 MWdc System-6,000 Panels-3 Locations--AC Output
Expected AC Power in kWh from System
800,000.000
700,000.000
600,000.000
500,000.000
Phoenix AZ
400,000.000
Bakersfield CA
300,000.000
Newark NJ
200,000.000
100,000.000
0.000
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
PV Mounting Systems
• Does your site location need to meet special building
requirements?
• What is the maximum wind speed that it must be designed for?
• What is the maximum snow loading that it must be designed for?
• What structures best use the soil type in your area?
• Can you drive piers directly into the ground or do you need
concrete? This will require a geotechnical study of the site and can
result in a significant cost savings.
• Can you use a ballasted system?
• What height does your system need to be to avoid being covered by
snow, or vegetation?
• If you decide to track, what are the lowest temperatures that
system will see?
Single Axis Tracking
Tracker A:
Individual drive for each row.
Electric screw jack drive
Backtracking controller
Variable spacing between rows
Height can be modified by user
Site welding required
Tracker B:
Single drive for multiple rows
Electric screw jack drive
Backtracking controller
Height limited by size of support
columns and Drive support.
Fixed row spacing
Site welding required
Site needs to be flat and level
Tracker C:
Single drive for multiple rows
Electric screw jack drive
Backtracking controller
Height limited by size of support
columns and Drive support.
Fixed row spacing
Site welding required
Site needs to be flat and level
Tracker D:
Single drive for multiple units
Electric screw jack drive
Backtracking controller
Height limited by size of support
Fixed row and column spacing
Site welding required
Site needs to be flat and level
A 2 AXIS
C 2 axis
B 2 AXIS
Your roof top is valuable real estate, without the permitting
problems associated with brownfield installations
Rack PV roof mounting
system
Accepts most standard PV
Roof loading dependent on
tilt angle
From 2 lbs/ft 2 with
penetrations to a ballasted
system with no
penetrations.
Examples of Roof Top Installs
Phizer = KW 337
Tilt Angle 5 deg.
Number of Modules 1,372
California Residence
2.5 kW, 20 panels
PV ARRAY
10 strings in parallel form an array
14 modules in series forms one string
Combiner box
DC Circuit Combiner
Inverter Input
1 MW PV Array
Sub Array Combiner Box with String Monitoring
Field Combiner Boxes
Grid Tie Inverter
Grid Tie Inverters
The grid tie inverter must synchronize its voltage & frequency with that of the grid. A
typical modern GTI has a fixed unity power factor.
Grid-tie inverters are also designed to quickly disconnect from the grid if the utility grid
goes down. This requirement ensures that in the event of a blackout, the inverter will
shut down to prevent harm to line workers who are sent to fix the power grid.
Peak power tracking voltage: This represents the DC voltage range in which the inverter
will operate. The designer must configure the strings so that during the majority of the
year, the voltage of the strings will be within this range. This can be a difficult task since
voltage will fluctuate with changes in temperature.
Most grid-tie inverters include a maximum power
point tracker on the input side that enables the
inverter to extract an optimal amount of power from
its intended power source.
Prewired System with Inverter, Transformer & Fused Combiner Boxes
Concentrated Solar
Power CSP
Rick Downer – POWER Engineers Inc.
IEEE IAS April 18, 2011