Agricultural/Bioengineering Renewable Energy 4

Question 1

Which greenhouse gas has the highest global warming potential over a 100-year period relative to CO2?

Accepted Answer

Nitrous oxide (N2O)

Answer

N2O has a GWP100 of ~265–298, higher than methane (~28–36), making it the most potent common agricultural GHG on this timescale.

Question 2

In a flat-plate solar collector used for crop drying, what material is typically used as the absorber plate to maximize heat absorption?

Accepted Answer

Black-painted metal sheet

Answer

A black-painted metal absorber maximizes solar radiation absorption across the spectrum while the selective coating minimizes re-radiation losses.

Question 3

What is the term for the ratio of electrical energy output to total solar energy input in a photovoltaic system?

Accepted Answer

Module efficiency

Answer

Module efficiency is the ratio of electrical power output to the solar irradiance × panel area, typically 15–22% for commercial silicon panels.

Question 4

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)?

Accepted Answer

8 m³/day

Answer

VS = 500 × 0.08 × 0.80 = 32 kg VS/day; biogas = 32 × 0.25 = 8 m³/day.

Question 5

Which type of wind turbine is most commonly used in small-scale agricultural applications due to its self-starting capability in low winds?

Accepted Answer

Horizontal-axis wind turbine (HAWT)

Answer

HAWTs dominate small-scale farm installations because they are efficient over a wide wind speed range and self-start reliably.

Agricultural/Bioengineering Practice Test

Agricultural/Bioengineering Practice Test

Agricultural/Bioengineering Renewable Energy 4