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