Chaper Review 1-8 Flashcards
(102 cards)
1
Q
What does balance of systems (BOS) refer to in a PV system?
A
Non major components required to complete a PV system
2
Q
What are concentrating and reflecting solar methods used for
A
Solar cooking
3
Q
Who was the first to invent and use PV cells as an energy source?
A
Bell Laboratories
4
Q
What association trains and certifies solar professionals?
A
NABCEP
5
Q
What percentage of total installed PV power in 2009 was the U.S. responsible for?
A
7%
6
Q
What does an integrator do in the PV industry?
A
Designs the PV system
Builds and puts together the PV system components
Installs the PV system on the roof
7
Q
What is an advantage to photovoltaic systems
A
Less cost for remote locations
8
Q
What type of radiation can a flat plat collector absorb
A
Direct and diffuse
9
Q
What is a disadvantage to photovoltaic systems
A
Lack of knowledge
10
Q
What is an example of solar energy technology
A
Solar cooking
11
Q
What information is found on a sun path chart
A
Solar altitude
Solar azimuth
12
Q
The solar irradiation received at a place over a particular time is
A
Insolation
13
Q
What is solar time measured by
A
From solar noon too solar noon
14
Q
What is the area of sky between the sun paths of summer and winter solstices
A
The solar window
15
Q
What is earths orbital position when we have equal length days and nights?
A
Equinox
16
Q
Which angle for an array is affected by the solar altitude
A
Array tilt
17
Q
Solar radiation can be measured by which instruments?
A
Pyranometer
18
Q
What is usually the best tilt angle of a PV collector in your area
A
Local latitude
19
Q
The hours required for a days total solar irradiation to accumulate at peak sun conditions
A
Peak sun hours
20
Q
What is the generally accepted measurement of peak sun power?
A
1000 W/m2
21
Q
What are some things a utility might require to connect to their system
A
Interconnection agreements
Interconnection policies
22
Q
Which on-line tool does NREL provide for estimating the performance of a PV system
A
PV watts
23
Q
Shading can have what effect on a PV modules energy output?
A
Reduction in output disproportionate to the array area shaded
24
Q
What codes should you be aware of for your project
A
Building codes: IRC, IBC
NEC
Municipal codes: AHJ
25
Why should we use energy conservation when designing a PV system
It can directly impact the size and cost of the PV system
26
What should you take into account to make your sun path calculator more accurate
Magnetic Declination
27
Why are major system components located near the main AC panel
To avoid voltage drop which causes loss of energy
28
What are some safety practices required for site surveying
Lock out tag out
Fall protection
PPE
29
What device can measure shading
Solar pathfinder
30
What PPE do you want to have for PV site surveys
Non slip composite toe shoes
Eye protection
Class E or G hard hat
31
What is a battery based completely self contained power source
Uninterruptible power supply
32
What does an inverter do
Coverts D.C. Power to A.C. Power
33
What does a charge controller do
Regulates the battery charging voltage level
34
What adjusts the load on a PV device under changing conditions to keep MPP?
Maximum power point tracker
35
What other electrical energy sources can be added to a hybrid PV systems
General
Wind turbine
Fuel cell
36
Which devices are added to a PV array to create a self regulated PV system
Battery
37
What are mechanical (BOS) parts in a PV system
Mounting hardware
38
Which devices are added to a PV array to create a utility interactive PV system
Inverter
39
What are electrical (BOS) parts in a PV system
Conductors
Switchgear
Over current protection devices
40
What type of PV system are the simplest and least expensive to produce AC
Utility interactive
41
When should you connect modules in series
When modules have the same current output
| When modules have the same solar irradiance on them
42
What relationship is being measured with a multi-meter on an I-V curve
Open circuit voltage to short circuit current
43
The highest efficiency for a module at a given irradiance and temperature is
MPP
44
What affect does solar irradiance have on a PV modules meter readings
Higher irradiance causes current to go up
45
When should you connect modules in parallel
When connecting 2 or more series strings
When connecting modules with different current outputs
When connecting modules that are facing different solar irradiance
46
What effect does temperature have on a PV modules meter readings
Higher temperature causes voltage to go down
47
What makes up the PV part of a solar power system
Cells
Modules
Arrays
48
What device is placed in parallel with cells to prevent reverse bias flow
Bypass diode
49
What are PV cells typically made from
Semiconductors such as silicon
50
Using the PIE triangle create the correct formula to find current
I = P/E
51
What type of battery is used in most PV systems
Traction battery
52
Why do we need ventilation in a battery enclosure
To safety vent combustible gasses such as hydrogen
53
Batteries connected in series and parallel for a specific voltage and capacity is a
Battery bank
54
The term used for the 80% a deep discharge battery can be discharged before damage
Allowable depth of discharge
55
How does discharge rate affect battery capacity
Lower discharge rate gives more energy for the charge cycle
| Higher discharge rate lowers the energy for that charge cycle to
56
What can you do to lessen stratification
Run an equalizing charge cycle to cause gassing mix up battery
57
What units are used to show battery capacity
Ampere hours
58
What device should be used to lessen watering in an open vent battery
Catalytic recombination cap
59
What term is used to define the percentage of withdrawn energy compared to full
Depth of discharge
60
What is autonomy in a battery solar power system
How long a system can run on batteries without further charging
61
What are features you can find in a charge controllers functions
Over charge/discharge protection
| Status information circuit protection
62
Points at which a controller preforming regulation and switching to limit charge or loads
Set points
63
What does a charge controllers temperature compensation do
Regulates battery charging based upon temperature
64
What advanced feature is incorporated in newer charge controllers
Maximum power point tracking
65
What considerations are required when designing a self regulated PV system
A well defined consistent load demand
| Low voltage modules
66
What considerations should be designed in locating a charge controller
Locate close to batteries to minimize voltage drop
67
What reasons would you design a system with multiple charge controllers
Multiple battery banks
| Multiple arrays
68
What UL listing do charge controllers fall under
UL 1741
69
What is a deficit charge
When less charge is returned to the batteries than was withdrawn
70
What battery charging modes can charge controllers help regulate
```
Bulk charge
Absorption charge
Float charge (trickle)
```
71
Many large PV inverters output 3-phase AC for what applications
Motors
| Commercial projects
72
What types of inverters are available in the PV industry
Stand alone
Utility interactive
Bi-modal
73
What features could you find on an inverters interface
Interconnection status
AC output D.C. Input energy production
Errors and faults
74
What listing should be on the inverters nameplate in order to connect to the grid
UL 1741
75
For interactive inverters what AC voltage output must be maintained
For 480v system: 432v to 504v
For 120v system: 180v to 126v
For 240v system: 216v to 252v
76
What inverter wave form is required for connecting AC loads to the utility
Sine wave
77
D.C. Input voltage ratings for stand alone systems are based on what
The battery bank voltage
78
What are the typical efficiency ratings for interactive inverters
90%to95%
79
What sophisticated feature does an AC module have that a charge controller has
MPPT
80
Interactive inverters can range in what power ratings
700 W to over 500 kW
81
What is system availability when sizing a system
% of time over a year the system meets load requirements
82
When selecting a battery bank what determines it's required capacity
The autonomy period during the critical month
83
What is the fine balance required when sizing a stand alone system
Supply vs. demand
84
In critical design the ratio of energy demand to insolation is found how often
Each month
85
In hybrid system design what is the typical range of solar to engine generators ratios
90% PV: 10% generator to 40% PV: 60% generator
86
When selecting an inverter what load should the inverter be rated for
Slightly larger than the largest AC load
87
What are the main limitations when sizing and interactive system
Space for the array
| Customers budget
88
In system sizing what is the simplest type of AC system to size
Utility interactive
89
When sizing a bi modal system which loads should you consider
Critical loads
90
The percentage of time a load is operating is called its
Duty cycle
91
When PV modules are substituted for regular building materials this mounting is called
Building integrated
92
Which building mounting systems do we use mostly because of heat issues
Rack mount
| Stand off mounted
93
What is the advantage of self ballasting mounts
No roofing penetration
94
A term for an electrochemical reaction between 2 metals corroding the weaker metal
Galvanic corrosion
95
Which tracking system type gains the most solar irradiance regardless of cost
2 axis
96
What structural loads do we consider when designing a PV array
Gravity loads like dead and live
Environmental loads like wind and snow
Mechanical loads like vibration
97
Why is it important to keep the array cool
The array will last longer and operate more efficiently
98
The safest and most practical means to access equipment and wiring is called
Accessibility
99
What applications are appropriate for pole mounted systems
Ground mounted systems with shading potentials
100
Which materials are best used for mechanical BOS
Hot dipped galvanized or coated steel
Stainless steel 316 and 403
Aluminum 6061 and 6063
101
When there are more then 3 current carrying wires in a conduit longer than 24"
Further sedate the conductors ampacity
102
When can max inverter current exceed nominal ratings for battery based systems
When the highest input current is matched with the lowest inverter operating voltage
