Test 9 Flashcards
PV-system sizing strategy starts at the array and proceeds backward to the load side.
False
Hybrid-system sizing calculations must use the worse-case load-to-insolation months for sizing.
False
Underestimating loads will result in a PV system that is too small and cannot operate the loads with the desired reliability.
True
A slightly oversized inverter is usually recommended to account for potential future load additions.
True
Some power is lost in the process of converting DC energy to AC energy.
True
The DC-system voltage is established by either the array voltage in battery-based systems or the battery-bank voltage in interactive systems.
False
Greater autonomy requires larger and costlier battery banks.
True
Low operating temperatures and high discharge rates increase battery capacity.
False
Generally, the number of parallel battery connections should be limited to no more than 3 to 4 strings.
True
The number of series-connected modules in each array string is determined by diving the rated array current by the selected module’s current output.
False
____ systems can be sized according to either the stand-alone methodology or the interactive methodology.
Bimodal
Sizing PV systems for stand-alone operation involves ____ set(s) of calculations.
four
____ may be used to help establish existing load requirements.
Measurements, meter readings, and electric bills (all of the above)
____ is the percentage of time a load is operating.
Duty cycle
The ____ ratio is the ratio of electrical energy demand to average insolation during a period.
critical design
The DC voltage for battery-based PV systems is usually an integer multiple of ____V.
12
System ____ is the percentage of time over an average year that a stand-alone PV system meets the system load requirements.
availability
Most PV systems use deep-cycle lead-acid batteries, which can be safely discharged to about ____%.
80
The ____ is the portion of load operating power that comes from the battery bank over the course of a day.
load fraction
____ is the accumulation of dust and dirt on an array surface that shades the array and reduces electrical output.
Soiling
____-system sizing is very flexible because the utility can supply extra energy to the system loads and receive excess energy from the PV system.
Interactive
In a(n) ____ system, the presence of multiple power sources allows for a smaller array while system reliability is improved.
hybrid
Electrical energy consumption is based on the electrical ____ demand over time.
power
If the loads are constant over the entire year, the critical design month is the month with the lowest ____ on the array surface.
insolation
____ is the amount of time a fully charged battery system can supply power to system loads without further charging and is expressed in days.
Autonomy
Of the critical design months for each orientation, the one with the smallest ____ is the best choice.
critical design ratio
The average battery bank ____ is determined from the total operating time over the period of autonomy.
discharge rate
The nominal voltage and rated ____ of the selected battery are used to determine the configuration of the battery bank.
capacity
For ____ systems, the array must be sized to produce enough electrical energy to meet all the load requirements during the critical design month.
stand-alone
The rated array voltage is multiplied by ____ to ensure that the maximum-power voltage is sufficient to charge the battery bank.
1.2
