Renewable Energy Flashcards
7 cards from real Agricultural/Bioengineering practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Renewable Energy flashcards as text
Which greenhouse gas has the highest global warming potential over a 100-year period relative to CO2?
Answer: Nitrous oxide (N2O)
N2O has a GWP100 of ~265–298, higher than methane (~28–36), making it the most potent common agricultural GHG on this timescale.
In a flat-plate solar collector used for crop drying, what material is typically used as the absorber plate to maximize heat absorption?
Answer: Black-painted metal sheet
A black-painted metal absorber maximizes solar radiation absorption across the spectrum while the selective coating minimizes re-radiation losses.
What is the term for the ratio of electrical energy output to total solar energy input in a photovoltaic system?
Answer: Module efficiency
Module efficiency is the ratio of electrical power output to the solar irradiance × panel area, typically 15–22% for commercial silicon panels.
A dairy farm produces 500 kg/day of manure with 8% total solids. Approximately how much biogas can be expected daily (assume 0.25 m³ biogas/kg VS, VS = 80% of TS)?
Answer: 8 m³/day
VS = 500 × 0.08 × 0.80 = 32 kg VS/day; biogas = 32 × 0.25 = 8 m³/day.
Which type of wind turbine is most commonly used in small-scale agricultural applications due to its self-starting capability in low winds?
Answer: Horizontal-axis wind turbine (HAWT)
HAWTs dominate small-scale farm installations because they are efficient over a wide wind speed range and self-start reliably.
What is 'co-digestion' in the context of agricultural anaerobic digesters?
Answer: Combining multiple feedstocks (e.g., manure + food waste) to improve biogas yield
Co-digestion blends substrates with complementary nutrient ratios (C:N balance) and moisture content to enhance methane production and digester stability.
In the context of renewable energy for irrigation, what is 'solar pumping'?
Answer: Using PV panels to power electric water pumps directly
Solar pumping systems use photovoltaic electricity to run DC or AC pumps for irrigation, eliminating diesel fuel costs in remote areas.