(SEM VII) THEORY EXAMINATION 2024-25 RENEWABLE ENERGY RESOURCES

SECTION A — Very Short Answers (2 Marks Each)

1. Fossil vs Non-Fossil Fuels

Fossil: Coal, oil, gas; finite; polluting         Non-fossil: Solar, wind, hydro; renewable; eco-friendly

2. Materials used in Solar Cells

Silicon (mono & polycrystalline)              Gallium arsenide

Cadmium telluride

3. Photovoltaic Cell

Device that converts solar energy directly into electrical energy using photovoltaic effect.

4. Solar Radiation

Electromagnetic energy emitted by the sun and received by Earth.

5. Geothermal Energy Resources

Heat energy stored beneath Earth’s crust in hot rocks, steam, and water.

6. Key Components of MHD Power Plant

Combustion chamber                                Magnetic field

Electrodes                                                  Power conditioning system

7. Electromagnetic Energy

Energy propagated as electric and magnetic waves (e.g., solar radiation).

8. Types of Wind Turbine Rotors

Single blade                                               Two blade

Three blade

9. Sources of Biomass

Agricultural waste                                       Animal dung

Municipal solid waste                                 Forest residues

10. OTEC: Benefits & Drawbacks

Benefits: Renewable, clean, continuous      Drawbacks: High cost, low efficiency

SECTION B — Short Notes / Analytical (10 Marks)

1. Role of Renewable Energy in Environmental Protection

Reduces greenhouse gas emissions           Conserves fossil fuels

Promotes sustainable development           Improves air quality

2. Flat Plate Solar Collector

Construction

Absorber plate                                            Transparent cover

Insulation                                                     Fluid tubes

Performance Factors                                 Solar intensity

Heat losses                                                  Flow rate

3. Magneto-Hydrodynamics (MHD)

Converts thermal energy directly into electricity

Ionized gas moves through magnetic field

No mechanical turbine required

4. Factors Affecting Thermoelectric Devices

Temperature difference                               Electrical conductivity

Material efficiency                                       Contact resistance

5. Tidal Power Plants

Advantages

Predictable energy                                       Renewable

Disadvantages

High capital cost                                          Limited locations

SECTION C — Conceptual (10 Marks)

Renewable vs Non-Renewable Energy

Grid Integration Challenges (Solar)

Intermittency                                                Voltage fluctuations

Storage requirement                                     Grid stability issues

SECTION D — Solar Energy Applications (10 Marks)

Types of Solar Collectors                              Flat plate collectors

Evacuated tube collectors                             Concentrating collectors

Applications

Water heating                                               Space heating

Industrial process heat                                  Thermal Energy Storage

Sensible heat storage (water, stones)            Latent heat storage (PCM)

SECTION E — Geothermal & Fuel Cell (10 Marks)

Geothermal Power Plant (Working)               Hot water/steam extracted

Steam drives turbine                                      Generator produces electricity

Condensate reinjected                                   Fuel Cell Performance Factors

Operating temperature                                  Pressure

Fuel purity                                                       Electrolyte quality

SECTION F — Wind & Thermoelectric Energy (10 Marks)

Types of Wind Turbines                                   Horizontal Axis Wind Turbine (HAWT)

Vertical Axis Wind Turbine (VAWT)                  HAWT Working

Wind rotates blades                                         Shaft drives generator

Electricity produced                                         Seebeck Effect

Voltage produced due to temperature difference between two conductors.

SECTION G — Biomass & Ocean Energy (10 Marks)

Biomass Conversion Technologies                     Combustion

Gasification                                                         Pyrolysis

Anaerobic digestion                                            Open-Cycle OTEC

Warm seawater → steam                                     Steam drives turbine

Condensed by cold seawater