Alternative Power (Workbook Questions)

Question 1

A photovoltaic cell or device converts sunlight to ____.

Answer 1

DC electrical energy

Question 2

PV systems operating in parallel w/the electric utility system are commonly referred to as ____ systems.

Answer 2

interactive

Question 3

PV systems operating independently of other power systems are commonly referred to as ____ systems.

Answer 3

stand-alone

Question 4

While PV cells produce only ____ power, PV systems can produce ____ power.

Answer 4

DC/AC or DC

Question 5

Compared to conventional power generating equipment, PV systems have relatively ____ life and require ____ maintenance.

Answer 5

long/low

Question 6

A primary distinction between PV systems and fossil fueled power plants or engine generators is that PV systems ____.

Answer 6

convert a basic form of energy directly to electricity.

Question 7

What are at least three limitations of PV systems?

Answer 7

1. High Initial cost
2. They require a relatively large area to produce a significant amount of power.
3. lack of knowledge about solar.

Question 8

What are the three main components of the electric utility system?

Answer 8

1. Utility 2. Grid 3. Distribution

Question 9

Solar power is commonly expressed in unites of ____.

Answer 9

watts per square meter or kilowatt-

Question 10

Solar energy is commonly expressed in units of ____.

Answer 10

watts-hours per square meter or kilowatt-hours per square meter

Question 11

The solar zenith angle is the angle between the ____.

Answer 11

sun and point in the sky directly overhead

Question 12

The angle between the earth’s equatorial plane and line jointing the centers of the sun and the earth is called the ____.

Answer 12

solar declination

Question 13

The apparent position of the sun with respect to an observer on earth at any given time of day is defined by its ____ and ____ angles.

Answer 13

solar altitude/solar azimuth

Question 14

The orientation of PV arrays is defined by their ____ and _____ angles.

Answer 14

tilt/azimuth

Question 15

For any location, which of these surfaces receives the greatest amount of annual solar radiation?

a. horizontal
b. south facing latitude tilt
c. single-axis tracking
d. dual axis tracking

Answer 15

Dual axis tracking

Question 16

Global solar irradiance is measured with a ____.

Answer 16

pyranometer

Question 17

A reference cell is essentially a ____.

Answer 17

photovoltaic device

Question 18

A shadow band pyrometer measures what?

Answer 18

diffuse radiation

Question 19

When working on low-slope roofs (pitch <= 4/12) with widths 50 feet or less, fall protection may be provided by:

Answer 19

1. a warning line system and personal fall arrest system
2. a warning line system and safety monitoring system
3. the use of a safety monitoring system alone.

Question 20

At most locations, a compass does not point true north due to ____.

Answer 20

magnetic delination

Question 21

Hard shadows covering 10% of a PV array surface area can reduce output by as much as ____.

Answer 21

90%

Question 22

What is the principal purpose for using a sun path calculator during a site survey?

Answer 22

To determine the extent of shading.

Question 23

A PV system using multiple power sources (in addition to a PV array) is called a(n) ____ system.

Answer 23

hybrid

Question 24

Which of these components are used in all PV systems?

energy storage, PV array, inverter

Answer 24

PV array

Question 25

Inverters are used in PV systems to convert ____ power to ____ power.

Answer 25

DC/AC

Question 26

Most interactive-only inverters use a(n) ____ as the input power source, while stand-alone inverters use a(n) ____as the input power source.

Answer 26

Utility/PV Array

Question 27

A charge controller protects a battery from overcharge by regulating the ____ and/or ____ delivered to the battery from a PV array.

Answer 27

terminating/limiting

Question 28

What is the principal reason for using energy storage in stand-alone PV systems?

Answer 28

To contain as much extra power as possible.

Question 29

This photovoltaic effect involves the conversion of sunlight into what basic form of energy?

Answer 29

electricity

Question 30

A photovoltaic cell consists of a junction between ____.

Answer 30

P-Type and N-Type semiconductor materials

Question 31

The current output of a solar cell depends on the ____.

Answer 31

Area of the cell, temperature and irradiance, and operating voltage.

Question 32

Dividing a larger solar cell into smaller pieces has what effect on the electrical output?

Answer 32

(voltage decreases and current increase) *confirm

Question 33

What is the smallest field-installable unit in a photovoltaic system?

Answer 33

PV module

Question 34

What are three factors that decrease lead-acid battery life?

Answer 34

1. operating temp 2. depth of discharge 3. materials

Question 35

List three factors that decrease the capacity of lead-acid cells.

Answer 35

1. temperature 2. discharge rate 3. depth of discharge

Question 36

Most battery charge controllers employed in PV systems use battery ____ to trigger charge control functions.

Answer 36

voltage

Question 37

What are four steps in sizing stand-alone PV systems.

Answer 37

1. battery bank 2. load 3. design 4. PV array

Question 38

Compared to a PV-only stand-alone system, hybrid systems can often be sized with a smaller ____ to meet a given system load.

Answer 38

battery - PV array

Question 39

Why are larger PV modules (or panels) preferred over smaller ones for larger arrays.

Answer 39

Larger modules typically involve less installation cost, time, and labor.

Question 40

A large PV array mounted in an open field is probably best installed using a(n) ____ mount.

Answer 40

rack