ES-301 Energy & Environmental Engineering - Jun 2023 Question Paper

Under each question, How to answer lists the points an answer should cover, outlined by CampusPrep from the syllabus. Check the details against your textbook.

1. 7 Marks
   aWhat are the Primary Goals of Sustainability?
   How to answer

   • Define sustainability and sustainable development.
   • List three primary pillars: environmental, social, and economic.
   • Key goals: poverty eradication, resource conservation, climate action, clean energy, ecological balance.
2. 7 Marks
   bHow can our energy system be more Earth-friendly?
   How to answer

   • Transitioning from fossil fuels to renewable energy sources (solar, wind, hydro).
   • Improving energy efficiency and conservation practices.
   • Decentralized power generation and smart grid integration.
   • Reducing carbon emissions and promoting green technologies.
3. 7 Marks
   aState advantage, disadvantages and applications of solar energy.
   How to answer

   • Advantages: Inexhaustible, clean, low maintenance, reduces carbon footprint.
   • Disadvantages: High initial cost, intermittency/weather dependence, large space/land requirement, storage costs.
   • Applications: Solar water heating, solar power plants, solar cooking, calculators, water pumping, rural electrification.
4. 7 Marks
   bHow does a forced circulation solar water heater differ from natural circulation solar water heater?
   How to answer

   • Natural circulation (thermosiphon): driven by density differences between hot and cold water; storage tank must be placed above collector.
   • Forced circulation: uses an external pump and control system to circulate fluid; storage tank can be placed anywhere.
   • Comparison on cost, maintenance, capacity, and efficiency.
5. 7 Marks
   aGive the classification of hydro-electric power plant. What are the criteria of site selection for hydroelectric plant?
   How to answer

   • Classification criteria: By water head (high, medium, low head), by capacity/load (base load, peak load), by water availability (run-of-river, storage, pumped storage).
   • Site selection criteria: Availability of water, water head availability, reservoir catchment area, geological conditions/rock structure, access to transport and load centers.
6. 7 Marks
   bDifferentiate between single-basin and double-basin tidal plants. Explain briefly the various components of tidal power plants.
   How to answer

   • Differences: Single-basin has intermittent power during flood/ebb tide; double-basin maintains head difference between two basins for continuous power generation.
   • Components: Barrage/dam, sluice gates, basin(s), low-head reversible turbines (bulb/Kaplan), generator and power house.
7. 7 Marks
   aWhat do you understand by concept of Green building? Explain.
   How to answer

   • Definition of green building: structure designed, built, operated to reduce or eliminate negative impacts on environment and climate.
   • Core principles: energy efficiency, water efficiency, sustainable materials, waste reduction, improved indoor air quality.
   • Lifecycle consideration from planning to construction, maintenance, and demolition.
8. 7 Marks
   bWhat is Energy conservation? Write down different methods of energy conservation.
   How to answer

   • Definition: Reducing energy consumption by using less of an energy service or using energy more efficiently.
   • Methods: Using energy-efficient appliances (LEDs, star-rated devices), waste heat recovery, regular maintenance of equipment, behavior adjustments/switching off unused devices, insulation of buildings/pipes, variable speed drives.
9. 7 Marks
   aWhat are semiconductors? What is the difference between intrinsic and extrinsic semiconductors?
   How to answer

   • Definition: Materials with electrical conductivity between conductors and insulators (e.g., Si, Ge).
   • Intrinsic: Pure form, no impurities, equal number of electrons and holes ($n_e = n_h$), low electrical conductivity at room temperature.
   • Extrinsic: Doped with trivalent or pentavalent impurities (p-type or n-type), high conductivity, unequal concentration of carriers.
10. 7 Marks
    bWhat is a photovoltaic cell? Explain briefly with a neat diagram a silicon photovoltaic cell.
    How to answer

    • Definition of photovoltaic (PV) cell: A semiconductor diode that converts light energy directly into electrical energy via the photovoltaic effect.
    • Construction: p-type and n-type silicon layers forming a p-n junction, top metallic grid/fingers, anti-reflective coating, back contact.
    • Working principle: Absorption of photons, generation of electron-hole pairs, separation by the junction electric field, and current collection.
    • Neat labeled diagram.
11. 7 Marks
    aExplain with a neat sketch the construction and working of wind-electric generating plant.
    How to answer

    • Neat labeled diagram showing rotor blades, hub, pitch mechanism, low-speed shaft, gearbox, high-speed shaft, brake, generator, anemometer, wind vane, yaw drive, and tower.
    • Constructional details of major components.
    • Working principle: Wind kinetic energy rotates aerodynamic blades $\rightarrow$ mechanical torque amplified via gearbox $\rightarrow$ drives electrical generator $\rightarrow$ electricity dispatched.
12. 7 Marks
    bExplain with a neat diagram the construction and working of floating drum type biogas plant. State also its advantages and disadvantages.
    How to answer

    • Neat labeled diagram of floating drum biogas plant (digester pit, partition wall, floating gas holder/drum, inlet pipe/tank, outlet pipe/tank, gas valve).
    • Construction details and working principle (anaerobic digestion of dung/slurry, gas collection under constant pressure).
    • Advantages: Constant gas pressure, visual indication of gas quantity, easy operation.
    • Disadvantages: High cost, steel drum prone to corrosion and requires regular painting/maintenance.
13. 7 Marks
    aWhat is LEED? What are the different LEED rating systems?
    How to answer

    • Definition of LEED: Globally recognized green building certification program developed by USGBC.
    • Rating levels: Certified, Silver, Gold, Platinum.
    • Different rating systems: Building Design and Construction (BD+C), Interior Design and Construction (ID+C), Building Operations and Maintenance (O+M), Neighborhood Development (ND), Homes.
14. 7 Marks
    bWhat is an energy audit? Explain briefly the difference between preliminary and detailed energy audits?
    How to answer

    • Definition: Systematic inspection, survey, and analysis of energy flows in a building/process to identify waste and opportunities for conservation.
    • Preliminary audit: Quick walk-through, relies on readily available past utility bills, identifies major energy-saving areas with low cost/effort.
    • Detailed audit: Comprehensive, involves quantitative measurements/instruments, detailed energy balance calculations, economic evaluation (payback, ROI), and an action plan.
15. 7 Marks
    aWhat impact do humans have on aquatic life zones?
    How to answer

    • Water pollution from industrial effluents, plastics, and municipal waste.
    • Agricultural runoff causing nutrient overload and eutrophication (hypoxic dead zones).
    • Overfishing leading to depletion of marine biodiversity.
    • Destruction of coastal/aquatic habitats (coral reefs, mangroves, wetland drainage).
    • Thermal pollution and climate change impacts (ocean warming, acidification).
16. 7 Marks
    bWhich gas does not cause Air pollution? Who had coined the term SMOG?
    How to answer

    • Non-polluting atmospheric gases: Major natural, clean constituents of air like Nitrogen ($N_2$), Oxygen ($O_2$), Argon ($Ar$), water vapor.
    • Coined SMOG: Dr. Henry Antoine Des Voeux in 1905 at the Public Health Congress in London.