Solar Energy Systems Flashcards

Soiling losses on PV panels are primarily caused by which of the following?

Answer: Dust, dirt, bird droppings, and other surface deposits

Soiling refers to the accumulation of contaminants on the panel surface that block incoming light and reduce output power.

What is the typical temperature coefficient of power (Pmax) for a standard crystalline silicon PV module?

Answer: -0.5% per °C

Most crystalline silicon modules lose approximately 0.3–0.5% of rated power for every degree Celsius above 25°C (STC).

In solar thermal systems, what does the 'stagnation temperature' refer to?

Answer: Maximum temperature reached when there is no fluid flow

Stagnation temperature is the highest temperature a collector can reach when fluid circulation stops and all absorbed heat remains in the collector.

Which PV cell technology generally has the highest commercial module efficiency?

Answer: Monocrystalline silicon (mono-Si)

Monocrystalline silicon modules achieve the highest commercial efficiencies, typically 20–23%, due to their highly ordered crystal structure.

What is 'net metering' in the context of a grid-tied solar PV system?

Answer: A billing arrangement where excess solar energy is credited against grid consumption

Net metering allows customers to send surplus PV energy to the grid and receive a credit on their utility bill, effectively running the meter backward.

Which interconnection standard governs the technical requirements for distributed energy resources connected to the electric grid in the US?

Answer: IEEE 1547

IEEE 1547 establishes requirements for the interconnection and interoperability of distributed energy resources with the electric power system.

A PV system's performance ratio (PR) is calculated as which of the following?

Answer: Actual energy output divided by theoretical energy output based on irradiance

Performance ratio compares actual kWh produced to the kWh theoretically possible given the irradiance received, indicating overall system quality.