Agricultural/Bioengineering Renewable Energy 3

Question 1

Which type of biofuel is produced by transesterification of vegetable oils or animal fats?

Accepted Answer

Biodiesel

Answer

Transesterification reacts triglycerides with an alcohol (usually methanol) and a catalyst to produce biodiesel (fatty acid methyl esters).

Question 2

In photovoltaic systems, what is the function of a maximum power point tracker (MPPT)?

Accepted Answer

Continuously adjusts operating voltage to extract maximum power from panels

Answer

An MPPT algorithm adjusts the electrical load impedance to keep PV panels operating at their peak power point under varying conditions.

Question 3

Which agricultural waste stream has the highest energy content per dry tonne for direct combustion?

Accepted Answer

Rice husk

Answer

Rice husk has a higher silica-adjusted heating value (~15 MJ/kg dry) compared to other crop residues, making it favorable for combustion.

Question 4

What is the primary role of a digestate separator in a farm biogas system?

Accepted Answer

Separates digestate into liquid fertilizer and solid fiber fractions

Answer

A screw press or centrifuge separator divides digestate into solid fiber (compost feedstock) and liquid (nutrient-rich fertilizer).

Question 5

A wind turbine has a rotor diameter of 20 m and operates in 8 m/s wind. Using Betz's law, what is the theoretical maximum power extractable (air density = 1.225 kg/m³)?

Accepted Answer

~77 kW

Answer

P_Betz = 0.593 × 0.5 × ρ × A × v³ = 0.593 × 0.5 × 1.225 × π×100 × 512 ≈ 77 kW.

Agricultural/Bioengineering Practice Test

Agricultural/Bioengineering Practice Test

Agricultural/Bioengineering Renewable Energy 3