Renewable Energy Systems Flashcards
A typical wind turbine has a sound pressure level of 38 decibels at a distance of how many metres?
500m
Solar energy is captured and converted into two basic forms :
Thermal energy
Photovoltaic energy
What are the four basic configurations used when designing a renewable energy system?
Stand-alone off-grid
Utility-interactive without batteries
Utility-interactive with batteries
A hybrid off-grid
What type of system is often used a backup system to supply critical loads in the even the grid becomes unavailable?
Utility-interactive system with batteries
What is the most complex system?
Hybrid off-grid:
Two or more energy sources in parallel, an array and wind turbine, both could supply dc to the inverter, and inverter supplies the load
What parts of a wind turbine located in the nacelle (housing) ?
Shaft, gearbox and generator
State some of the benefits of Annular Generator Technology:
Reduced transmission losses
The elimination of wear and tear of the gear box
The elimination of oil leakage
What is an anemometer?
A wind meter
Utility-interactive inverters can be classified as 5 different types:
String inverters
Central inverters
Utility-scale inverters
Multi-mode inverters
Module-level (microinverters)
What is a charge controllers primary function?
Regulate the dc power to protect the battery bank from over-charging.
(regulate current to a trickle charge)
Three main categories of wind systems:
Grid-connected systems without batteries
Grid-connected systems with batteries
Off-grid systems
Define a dump load controller
Regulates output power of a micro-hydropower system by adjusting the amount of energy flowing into the ballast load to compensate for main load variations, such as stand-alone systems, and to prevent generator overvoltage.
What’re the three main types of crystalline silicon solar cells?
Mono 12-16%
Multi or poly 8-11%
Amorphus 5-6%
What is Solar cell efficiency?
The ratio of the electrical output of a solar cell to the incident energy in the form of sunlight
What are the Standard Test Conditions of PV Systems?
Irradiance if 1000w/m
Solar spectrum of air mass (AM) 1.5
Cell or module temperature at 25 degrees
Silicon is a shiny gray material that can act as a mirror by reflecting more than __% of the light that shines on it.
30%
PV action could theoratically continue indefinitely if the cell is struck by light radiation from the sun. T or F?
True
The process of converting photons to voltage is called:
Photovoltaic action
Describe the relationship of voltage to the temperature of silicon.
Voltage is inversely proportional to the temp of silicon
What determines the voltage of a PV cell?
The material of the cell
The cell temperature
What does an MPPT circuit do?
Monitors array conditions (insolation, array temp)
Dynamically changes arrays resistance
What is the heart of all PV systems?
The inverter
A combination of the grid-tie and stand-alone inverter is called a __________
Bimodal inverter
What two things does a microinverter add to a PV system?
Adds to overall cost
Adds flexibility
Describe the two classes of dc-to-dc converters:
Boost converter- common to step up the voltage from a dc source
Buck converter- takes a high voltage from the dc source and bucks it down to a lower value
