photovoltaic
The peak solar irradiance on a surface facing the sun at solar noon at most sea level locations on a clear da, also referred to as "peak sun: is assumed to be ___
1000 w/m^2
What value of solar irradiance is most commonly used to rate the output of PV modules and arrays
1000 w/m^2
The first practical silicon solar cell was made in ___
1954
List the two documents that address the safety of firefighters in regards to roof mounted pv arrays
2018 international fire code, NFPA uniform fire code
The peak solar irradiance incident on the earths surface is approximately ___ of the extraterrestrial irradiance
73%
A semiconductor material generally exhibits properties of ___
A conductors or and insulator
What value of air mass is considered representative of average terrestrial conditions in the united states and used as a reference condition for rating modules and arrays
AM0
List three purposes for conducing a site survey in advance of PV installations
Customer needs and expectation, Appropriate location, Shading, Size systems and design, Bids, Installation
A photovoltaic cell or device converts sunlight to ___
DC electrical energy
The photovoltaic effect involves the conversion sunlight into what basic form of energy
DC electricity
Inverters are used in PV systems to conver ___ power to ___ power
DC to AC
an inverter is a device that changes ___ to ___ power
DC to AC
While PV cells produce only ___ power, PV systems can produce ___ power
DC, AC, or both
List the examples provided in the reference text to include in a hazard assessment checklist
Electrical hazards, falls, falling objects, impacts, penetrations, cuts, heat and chemical exposure
Most PV modules produced and installed today are what type of collector?
Flat plate
A photovoltaic cell consists of a junction between ___
N type and P type
Which of the following components are used in all PV systems
PV array
Most interactive inverters use a ___ as the input power source, while stand alone inverters use a ___ as the input power source
PV array, Battery
What is the smallest field installable unit in a photovoltaic system?
PV module
What is the principal reason for using energy storage in stand alone PV systems?
Power produced by PV array does not always co-inside with equipment
An AC powered battery charger typically contains which of the following components
Rectifier, Transformer, Filters
List three methods for evaluating potential shading from tall obstructions near a proposed PV array installation
Solar path finder, profile angle method, photograph method
3 functions of batteries in standalone PV systems
Surge loads, Establishes systems and load operating voltage, Operates the PV array close to maximum power point
What are features of direct coupled PV systems
They use no charge control, They use no electrical energy storage, they use no inverter
list three factors affecting air mass
Time of day, time of year, altitude and latitude
The orientation of PV arrays is defined by their ___ and ___ angles
array tilt, array azimuth
Equipment other than major components in a PV system are referred to as ___ components
balance of system
What ancillary function is often provided with stand alone inverters to utilize an independent AC energy source
battery charger
Voltage source stand alone inverters use a ___ as the DC power source, while current source interactive inverters use a ___ as the DC power source
battery, pv array
what element is typically added to silicon in small amounts to produce a p-type semiconductor material?
boron
List four types of small electronics devices that may use photovoltaic cells for primary power or battery charging
cell phones, calculations, radios, GPS receivers
List three desirable features of PV systems
clean no emissions, no moving parts, free and renewable fuel source
The first markets for PV systems were comprised largely of ___ applications
comprised
A charge controller protects a better from over charge by regulating the ___ and ___ delivered to the battery from a PV array
current and voltage
a shadow band pyranometer measures what?
diffuse radiation
Typical flat plate photovoltaic modules utilize which components of solar radiation
direct and diffuse
concentrating PV modules utilize which components of solar radiation?
direct only
For any location which of the following surfaces receives the greatest amount of annual solar radiation
dual axis tracking
What factors determine the operating point on any given I-V curve?
electrical load
A p-type semiconductor material has an excess of ___
electron voids
Electrical loads used for stand alone PV systems should be as ___ as possible to minimize the size and cost of system required
energy efficient
peak sun hour data is used for estimating the ___
energy output of PV modules and arrays over time
List the two steps in the manufacturing of silicon solar cells that reduce reflected sunlight and improve cell efficiency
etching wafers, anti reflective surface coating
PV systems can be installed by almost anyone with little training
false
An interactive PV system employing AC modules does not require ___
field installed DC wiring
List four components of the electromagnetic spectrum
gamma rays, infrared radiation, microwaves and radio waves
What process is typically used for applying n-type semiconductor material to a p-type silicon wafer?
gas diffusion
List the three main components of the electric utility system
generation, transmission, and distribution
In general, PV arrays at higher latitudes are tilted at ___ tilt angles than those at lower latitudes to maximize solar energy gain
high
Photons striking a solar cell must have energies above a certain minimum energy level to create the photovoltaic effect. Higher energy photons are associated with which of the following?
higher frequency
A PV system using multiple power sources (in addition to a PV array) is called a ____ system
hybrid
the load resistance required to operate a PV module at its open circuit voltage is ___
infinite
Solar power is used to estimate the ___
instantaneous output of PV modules and arrays
PV systems operating in parallel with the electric utility system are commonly referred to as ___ systems
interactive
What type of PV system is intended to operate in parallel with the electric utility system?
interactive
Multimodal inverters operate normally in ___ mode, and in the event of grid failure switch to operation in ___ mode
interactive, stand alone
Which of the following components are considered power conditioning equipment?
inverts, converters and controllers, battery chargers and rectifiers, maximum power point trackers
Which of the following terms may be used to describe solar?
isolation, irradiance, peak sun hours
Why are temperature extremes at a site important to know in planning for PV installations
it affects the output of PV arrays
to maximize wintertime output, PV arrays are generally tilted at an angle closest to ___
latitude + 15
List two advantages of distributed power generation
less transmission and distribution losses utility back up
What type of interactive inverter uses an external AC source to control switching and synchronization functions
line communtated
Only inverters and AC modules ___ and ___ as ___ shall be permitted in grid tied PV systems
listed, identified, interactive (705.6)
The size and cost of any stand alone PV systems is directly related to what two factors?
load energy requirements, solar energy resource
Compared to conventional power generating equipment, PV systems have relatively ___ life and require ___ maintenance
long/low
At most locations a compass does not point true north due to ___
magnetic declination
Concentrating PV arrays use ___ or ___ to focus the suns power on a smaller area
mirror or lenses
what type of inverter can operate in either stand alone or interactive mode?
multimodal
The electrical contacts on the top surface of a silicon solar cell are typically what polarity?
negative
List at least three limitations of PV systems
off grid
the function of bypass diodes are to protect cells in PV modules from ___
overheating
List six characteristics of qualified PV system installers or contractors
page 16 list
A primary distinction between PV systems and fossil-fueled power plants or engine generators is that PV systems ___
produce free electricity, convert a basic form of energy directly to electricity, require no maintenance
Global irradiance is measured with a ___
pyranometer
What instrument is used to measure direct beam solar irradiance?
pyrheliometer
Air mass (AM) is a representation of the ___
relative distance of atmosphere that radiation must travel through to reach the earths surface
In addition to using a free, renewable fuel source, what are two key environmental benefits of PV systems?
renewable energy, no noise, no pollution
What is the primary requirement of interactive inverters or AC modules to prevent islanding
risk to personnel and equipment (705.40 info note)
List three atmospheric effects on solar radiation
scattering, reflection, and absorbtion
PV systems that use batteries without charge control are referred to as ___ systems
self regulating
Typically PV modules are connected in ___ to achieve a desired voltage output, then connected in ___ to build power output
series and parallel
when evaluating potential PV array locations, the most important consideration is ___
shading
why do high frequency inverter designs weigh less than low frequency designs with the same power rating?
smaller transformer can be used
total global solar radiation reaching the earths surface is composed of ___ and ___ radiation
solar and diffuse
A ___ PV system operates autonomously and supplies power to electrical loads independent of the utility grid
stand alone
PV systems operating independently of other power systems are commonly referred to as ___ systems
stand alone
photovoltaic applications for spacecraft, remoted power and portable equipment would be considered what type of systems?
stand alone
inverters used in PV systems are ___
static and solid state
The solar zenith angle is the angle between the ___
sun and point in the sky directly overhead
The first terrestrial applications for photovoltaics were ___
telecommunication systems
What primary effect does increasing solar irradiance have on the electrical output of a solar cell?
the current increases proportional to irradiance
Some charge controllers protect a battery from excessively deep discharges by disconnecting ___
the system loads
What effect does increasing operating temperature have on a typical silicon solar cell output?
the voltage decreases and current increases slightly
what is the principal purpose for using a sun path calculator during a site survey?
to determine the extent of shading
A ___ switch is used to disconnect an electrical system from a primary source of power and connect it to a backup source
transfer
what three components of the electromagnetic spectrum are contained in solar radiation?
ultra violet light, visible light, and infrared radiation
What happens when an illuminated solar cell is short circuited?
voltage and power are zero
Solar power is commonly expressed in units of ___
watts per square meter
Solar energy is commonly expressed in units of ___
watts per square meter or kilowatts per square meter
Balance of system components typically include which of the following?
wiring, conduit, switchgear, and overcurrent protection
