Energy science and engineering AKTU question paper – 2021-22

This is the solution to the previous year’s question paper (2021–2022). Here we explore the Energy science and engineering AKTU question paper. I hope this session will help you to prepare for your Energy science and engineering AKTU question paper.

Dudes 🤔.. You want more useful details regarding this subject. Please keep in mind this as well.

Important Questions For Energy science and engineering : 
*Unit-01     *Unit-02    
*Unit-03    *Unit-04 
*Unit-05    *Short-Q/Ans
*Question-Paper with solution 21-22 

Q. Comment on the statement: “The entropy of the universe tends to be maximum”.

Ans. This rule states that the entropy of an isolated system can never decrease. It always rises and only stays the same when the process can be reversed.
Mathematically,                                ds_iso ≥ 0

Q. What is the significance of BTU?

Ans. British Thermal Unit is the abbreviation. It is a measurement that depicts the precise amount of energy required by our air conditioner to remove the heat from our house in one hour. It can help us determine the type of air conditioner we need for a house our size.

Q. Differentiate between fusion and fission nuclear reactions.

Q. Is the average binding energy of electrons in an atom independent of Z (number of proton)?

Ans. Yes, the average electron binding energy in an atom is independent of Z. (number of protons).

Q. Describe the operation of a solar cell.

Ans.

• 1. When light reaches the p-n junction, photons of light can easily enter the junction due to the very thin p-type layer.
• 2. Light energy, in the form of photons, provides enough energy to the junction to form a number of electron-hole pairs.
• 3. The incident light breaks the thermal equilibrium condition of the junction.
• 4. The free electrons in the depletion region can quickly reach the junction’s n-type side. Similarly, the depletion holes can quickly reach the p-type side of the junction.
• 5. The barrier potential of the junction prevents newly produced free electrons from continuing to cross it once they reach the n-type side. Similar to this, once the freshly formed holes reach the p-type side of the junction, they are unable to cross it again due to the junction’s inherent barrier potential.
• 6. The p-n junction will behave like a small battery cell as the concentration of electrons increases on one side, i.e., the n-type side of the junction, and the concentration of holes increases on the other side, i.e., the p-type side of the junction.
• 7. A voltage known as photovoltage is created. A tiny current will flow through the junction if we connect a small load across it.

Q. Discuss the latitude angle and hour angle.

Ans.  
a. Latitude Angle ( ) :

• 1. The latitude of a location is the angle formed by the radial line connecting the location to the centre of the earth and its projection on the equatorial plane.
• 2. The latitude is taken as positive for any location towards the northern hemisphere and negative for any location towards the southern hemisphere, i.e., the latitude at the equator is 0°, while the latitudes at the north and south poles are + 90° and -90°, respectively.

b. Hour Angle ( ) :

• 1. It is the angle at which the earth must be rotated to bring a point’s meridian directly in line with the sun’s ray.
• 2. In other words, it is the angular displacement of the sun east or west of the local meridian caused by the earth’s rotation on its axis at 15° per hour.

Qg. Explain warm spring in geothermal energy.

Ans. Rain and snow melt into groundwater that seeps through the Earth’s crust, hits solid rock, and collects in pools or aquifers to form warm springs. This water is heated by magma, which causes it to rise to the surface again through vents in the earth’s crust and create a warm spring.

Qh. State the limitations of OTEC system.

Ans. Limitation of OTEC system are as follows:

• 1. Capital investment is very high.
• 2. Conversion efficiency is extremely poor, ranging between 3 and 4%, as a result of the minimal temperature differential between the surface and deep waters.
• 3. Because of their low efficiency, as well as their high capital and maintenance costs, these plants are uneconomical for small plants.

Qi. Discuss the energy audit and its types.

Ans. Energy Audit: An energy audit is an examination for improving energy efficiency through analysis of energy usage. It identifies energy-saving opportunities, which are then assessed to determine savings.

Types of Energy Audit:

• a. Envelope Audit
• b. Functional Audit
• c. Process Audit
• d. Transportation Audit
• e. Utility Audit

Qj. What are the alternative to deal with energy crises?

Ans. Alternatives to dealing with energy crises include renewable energy resources such as solar energy, wind energy, hydropower, geothermal energy, and biomass energy.

Section – B

Qa. Explain the concept of quantum. Also, describe the concept of quantization of energy.

Ans. A. Concept of Quantum:

• 1. A quantum is the smallest amount of any physical entity involved in an interaction in physics.
• 2. The fundamental notion that a physical property can be “quantized” is referred to as “the hypothesis of quantization”.
• 3. This means that the physical property’s magnitude can only have discrete values that are integer multiples of one quantum.
• 4. A photon, for example, is a single quantum of light (or of any other form of electromagnetic radiation).
• 5. Similarly, the energy of a bound electron within an atom is quantized and can only exist in discrete values.

B. Concept of Quantization of Energy:

• 1. Only integral multiples of a quantum can have their energy added or subtracted. Energy has been quantized in this way.
• 2. It also refers to the absorption or emission of energy in discrete packets or quant.
• 3. Instead of following a smooth and continuous curve, electromagnetic energy steps up or down from one quantized level to another as its intensity rises or falls.
• 4. Energy quantization became evident under following three main studies:
  • i. Black body radiation,
  • ii. Heat capacities, and
  • iii. Atomic and molecular spectra.

Qb. Illustrate the working principle of nuclear forces and also outline the different energy scales used in nuclear energy.

Ans.
A. Working principle of Nuclear Forces:

• 1. The forces that operate between two or more nucleons are referred to as nuclear forces, nuclear interactions, or strong forces. They create atomic nuclei by joining protons and neutrons.
• 2. The chemical bonds that keep the atoms in molecules together are around 10 million times weaker than the nuclear force. Because of this, nuclear reactors generate around a million times more energy per kilogramme of fuel than chemical fuels like coal or oil.
• 3. The nuclear force can only be applied within a few femtometers (1 f = 10–15 m), after which it rapidly degrades. This explains why, despite this force’s immense power, we are completely unaware of it at the atomic level or in daily life.
• 4. The nuclear force is thought to exist today as a remnant interaction of the even stronger force between quarks, which is mediated by the exchange of gluons and holds the quarks together inside a nucleon (akin to the van der Waals force between neutral atoms).

B. Energy Scales used in Nuclear Energy:

• 1.Femto (10^-15): Femto refers to something that is in the 10^-15 range.
  • Uses: Femtosecond lasers are a specific type of laser that are used in specific types of medical facilities. Femtosecond lasers are thus lasers that are “on” for a second before turning “off.”
• 2. Pico (10^-12): Pico refers to something that is in the 10^-12 range.
  • Uses: High precision power supply used in labs to monitor current, voltage, and resistance of certain samples with extreme precision.
• 3. Nano (10^-9): Nano refers to something that is in the 10^-9 range.
  • Uses: Electron micrograph is an example of instrument using 10^-9 range.
• 4. Micro (10^-6): Micro refers to something that is in the 10^-6 range.
  • Uses: In measuring instrument in the fields of science and engineering.
• 5. Milli (10^-3): Milli refers to something that is in the 10-3 range.
  • Uses: A typical scientific calculator uses power in the scale of 0.1 milli Watt.
• 6. Kilo (10³): Kilo refers to something that is in the 103 range.
  • Uses: In solar panels and batteries in Hubble space telescope.
• 7. Mega (10⁶): Mega refers to something that is in the 106 range.
  • Uses: Used in large vehicles like submarines.
• 8. Giga (10⁹): Giga refers to something that is in the 109 range.
  • Uses: A modern mobile phone can store data in several gigabytes thanks to its built-in storage, which ranges from 16 to 64 GB.
• 9. Tera (10¹²): Tera refers to something that is in the 1012 range.
  • Uses: Cameras and computers today uses hard disks in the terabyte scale.
• 10. Peta (10¹⁵): Peta refers to something that is in the 10¹⁵range.
  • Uses: Today’s supercomputers operate in hundreds of petaflops.
• 11. Exa (10¹⁸) : Exa refers to something that is in the 10¹⁸ range.
  • Uses: 10¹⁸ is a kind of a quantity that is indicated with prefix exa, the world today uses energy in the range of 500 exa joules.
• 12. Zetta (10²¹): Zetta refers to something that is in the 10²¹range.
  • Uses: According to estimates, the amount of data created and stored by humanity as a whole surpassed the 1 zettabyte threshold in 2010. By 2020, we may have reached 7 zettabytes.
• 13. Yotta (10²⁴): Yotta refers to something that is in 10²⁴ range.
  • Uses: When we compare it to something on the scale of the cosmos and galaxies, we can comprehend this scale.

Qc. Differentiate between a type n and p type of semiconductor along with energy band diagram.

Ans. Difference between the p and n type:

Qd. Outline the working principle of the tidal power plant. Discuss their advantages and limitations. Also, give the present status of tidal power in INDIA.

Ans.
A. Working Principle of Tidal Power Plant: In order to use tidal energy, water must first be manipulated to generate a turbine as it returns to the sea during low tides after being trapped at high tide behind a dam or barrage. The amplitude squared determines the amount of energy that is available.

Advantages of Tidal Power:

• 1. By establishing a barrage, the coastline is protected from storm tidal damage.
• 2. The main advantage of the tidal power plant is that it is inexhaustible.
• 3. It produces electricity reliably.
• 4. It is unaffected by the changing mood of nature such as the failure of monsoon.
• 5. It is pollution free.

Limitations of Tidal Power:

• 1. Initial capital cost of the plant is very high and needs long constructional period.
• 2. Output power is variable due to uneven operation.
• 3. Sedimentation of the basin is a serious problem.
• 4. Due to the variable tidal range, the efficiency of the plant is affected.
• 5. Marine life is affected.

B. Present Status of Tidal Power in India:

• 1. Tidal power has not been used on a commercial basis in India and is currently in the research and development (R & D) stage.
• 2. Early attempts to capture tidal power failed because of the high capital costs, which ranged from Rs. 30 crore to Rs. 60 crore per MW.
• 3. The Indian government estimates that the country has a tidal energy potential of 8000 Mw.

Qe. Illustrate the short about the following:
A. Ways of disposal of nuclear waste fuels.
B. Energy crises

Ans.
A. Ways of disposal of nuclear waste fuels are as follows:

i. Incineration: It is common with low-level waste because it typically consists of contaminated clothing or other common items.

ii. Shallow Burial:

• 1. Highly radioactive material is difficult to bury, but mill tailings can often be buried in a specially designed spot near the mill itself.
• 2. This frequently entails building a pile of tailings and covering it with a non-permeable material, such as clay.
• 3. To prevent erodibility, the pile is usually buttressed by a mix of rocks and soil.

iii. Deep Burial:

• 1. While shallow burials can be used for low-level waste, deep burial pits are the most common way to dispose of high-level waste.
• 2. Many countries with natural resources use this geological disposal method, which involves burying the material deep within the earth.

iv. Recycling :

• 1. Certain radioactive elements can be processed or extracted for reuse from some radioactive materials, such as previously used fuel.
• 2. Because uranium and plutonium have long lives, they can be separated and recycled.

B. Energy Crisis :

• 1. The energy crisis is caused by the impending end of the oil, gas, and coal cycles, which have also resulted in a significant increase in greenhouse gases (GHG).
• 2. Many scientists have raised their voices in recent years to warn about climate change, which is primarily caused by the use of oil and coal to generate energy.
• 3. Global energy consumption is rising, and we will face a fossil fuel shortage in the coming decades. As a result, the availability of reserves is a major source of concern.

Section – C

3. Attempt any one part of the following:                                                        (10 x 1 = 10)

Qa. Illustrate the working of Carnot heat Engines with p-v and T-s diagram.

Ans. Carnot Cycle:

• 1. It is a perfect cycle with the highest thermodynamic efficiency. Carnot cycle is shown in Fig.
• 2. Various processes of Carnot cycle are as follows:
  • a. Process 1-2: It is reversible isothermal heat addition process in the boiler.
  • b. Process 2-3: It is reversible adiabatic expansion process in steam turbine.
  • c. Process 3-4: It is reversible isothermal heat rejection process in the condenser.
  • d. Process 4-1: It is reversible adiabatic compression process or pumping process in feed water pump.

Qb. Examine the phase change energy conversion. Describe the different operations of the Rankine cycle with the help of a diagram.

Ans.
A. Phase Change Energy Conversion: The phase change process is the transformation of a material’s physical state from one state to another, such as solid to liquid and vice versa. During the phase change process, the material makes use of its latent heat.

B. Rankine cycle:

• 1. The theoretical steam cycle on which the steam turbine (or engine) operates is known as the Rankine cycle.
• 2. The Rankine cycle is shown Fig. It consists of following process:
  • a. Process 1-2: Adiabatic expansion (in turbine).
  • b. Process 2-3: Isobaric heat release (in condenser).
  • c. Process 3-4: Adiabatic pumping (in Pump).
  • d. Process 4-1: Isobaric heat addition (in boiler).
• 3. Fig. shows T-s diagram of Rankine cycle.

4. Attempt any one part of the following:

Qa. Draw the binding energy curve showing variation of binding energy per nucleon with mass number. With the help of this explain the phenomenon of nuclear fusion and fission and stability concept of nuclei.

Ans.
A. Binding Energy Curve :

1. The binding energy curve is the graphical relationship between binding energy per nucleon and mass number.

2. Fig. shows binding energy curve. For naturally occurring nuclei, the average binding energy per nucleon is plotted against mass number. The following are the unique characteristics of the binding energy curve.

• i. The binding energy per nucleon of very light nuclides like H is extremely low.
• ii. The curve begins with a steep rise. This indicates that the value of binding energy per nucleon is rapidly increasing.
• iii. Between mass number 4 and 20, the curve shows cyclic recurrence of peaks corresponding to ⁴₂He, ⁸₂Be, ¹²₆C, ¹⁶₈O and ²⁰₁₀Ne. This demonstrates that the binding energy per nucleon of these nuclides is greater than that of their neighbours.
• iv. Binding energy per nucleon gradually increases after mass number 20.The maximum value is reached at A = 56. This value is 8.8 MeV. Clearly, the iron nucleus (⁵⁶₂₆Fe) is the most stable.
• v. The binding energy per nucleon of nuclides with mass numbers ranging from 40 to 120 is nearly maximum. As a result, these elements are extremely stable and non-radioactive.
• vi. The value declines and drops to 7.6 MeV for uranium when A = 120. The main cause of this decrease is repulsion between protons, whose quantity rises in heavy nuclides.
• vii. Beyond A = 238 the binding energy for each nucleon rapidly decreases as the mass number increases.
• viii. There are significant practical ramifications to the binding energy curve drooping at both high and low mass values.

B. Phenomenon of Nuclear Fusion and Fission:

1. The drooping of the binding energy curve at high mass numbers indicates that nucleons are more tightly bound when assembled into two middle mass nuclei as opposed to a single high mass nucleus. This is referred to as nuclear fission.

The drooping of the binding energy curve at low mass numbers, on the other hand, indicates that energy will be released if two small mass number nuclei combine to form a single middle mass number nucleus. This process, which is the inverse of fission, is known as nuclear fusion.

 C. Stability Concept of Nuclei:

• 1. The stability of a nuclear of an atom is referred to as nuclear stability.
• 2. A stable nucleus does not decay on its own.
• 3. Radioactive elements have unstable nuclei that spontaneously decay, emitting various radiations.

Qb. Illustrate the concept of nuclear fission reactor design with the help of diagram. Explain PWR type of fission reactor.

Ans. A. Nuclear Reactor :

• 1. The nuclear reactor can be viewed as a replacement for a steam power plant’s boiler fire box or a gas turbine plant’s combustion chamber.
• 2. In contrast to steam and gas power plants, where heat is generated by the combustion of fuel, nuclear reactors generate heat through the fission process.
• 3. The other cycle of operation and components required are the same whether the plant is a steam or a gas turbine.
• 4. The working fluid in a nuclear power plant could be steam or gas.

B. Pressurized Water Reactor (PWR):

• 1. A pressurised water reactor is a light water-cooled, moderated thermal reactor with an unusual core design that can use both natural and highly enriched fuel.
• 2. The principal parts of PWR are:
  • a. Pressure vessel,
  • b. Reactor thermal shield,
  • c. Fuel elements,
  • d. Control rods,
  • e. Reactor containment, and
  • f. Reactor pressurizer.
• 3. The primary circuit in a PWR is radioactive because it passes through the fuel core.
• 4. This primary circuit then generates steam in a secondary circuit comprised of a heat exchanger or boiler and a turbine.
• 5. Because the steam in the turbine is not radioactive, it does not need to be shielded.
• 6. The pressure in the primary circuit should be high enough that water boils at high pressure.
• 7. A pressuring tank keeps the water at about 100 kgf/cm² so that it will not boil.
• 8. The pressurizer’s electric heating coil boils some of the water, resulting in steam that collects in the dome.
• 9. As more steam is forced into the dome, the pressure inside it rises.
• 10. Pressure can be reduced by using cooling coils or spraying water on the steam.
• 11. Water acts both as coolant as well as moderator.
• 12. Only saturated steam can be produced by a pressurised water reactor. The reactor’s steam could be superheated by providing a separate furnace.

5. Attempt any one part of the following:                                                      (10 x 1 = 10)

Qa. Outline the concept of basic physics of semiconductors, carrier transport, generation and recombination in semiconductor and semiconductors junction.

Ans.
A. Basic Physics of Semiconductors:

a. Direct Band Gap Semiconductors:

• 1. An electron in the conduction band falls directly to the valence band in direct band gap semiconductors, emitting the energy difference E as a photon of light.
• 2. It cannot change in energy or momentum.
  • Example: GaAs, GaN etc.

B. Indirect Band Gap Semiconductors:

• 1. An electron in the conduction band falls indirectly to the valence band in indirect band gap semiconductors, transferring energy to the lattice in the form of heat.
• 2. It changes its momentum as well as its energy.
  • Example: Si, Ge etc.

B. Carrier Transport:

a. Charge Carrier Concentration for p-type Extrinsic Semiconductor:

• 1. We make a p-type extrinsic semiconductor by doping a group 4A element (such as silicon) with small amounts of group 3A elements (such as boron, aluminium, gallium, indium, and thallium).
• 2. These group 3A elements are potentially incapable of capturing an electron or, put another way, of releasing that vacant place since they have one valence electron fewer than silicon. A hole is the term for this release of empty space.
• 3. Acceptor levels, which are located just above the valence band, are now available and can readily receive electrons. In contrast, the Fermi energy level in an intrinsic semiconductor is exactly halfway between the valence band and the conduction band. It effectively aligns up at the acceptor levels for a p-type extrinsic semiconductor.
• 4. This has a significant impact on how the semiconductor behaves. Now, temperature is not the only factor affecting the charge carrier concentration. We discover that the charge carrier concentration solely depends on the dopant concentration for a large portion of the temperature range.
• 5. As a result, increasing the dopant concentration results in a higher charge carrier concentration over the entire temperature range.
• 6. We can reduce the charge carrier concentration by decreasing the dopant concentration over the entire temperature range. Again, conductivity is affected by dopant concentration because it is affected by charge carrier concentration.

b. Charge Carrier Concentration for n-type Extrinsic Semiconductor:

• 1. The charge carrier in an n-type extrinsic semiconductor differs fundamentally from the charge carrier in a p-type.
• 2. We make an n-type extrinsic semiconductor by doping a group 4A element (such as silicon) with small amounts of group 5A elements (such as nitrogen, phosphorus, arsenic, antimony, and bismuth).
• 3. These elements have essentially one additional valence electron available to them, and that valence electron is available for more free movement within the system, and thus this electron begins to run around the system at very low energy availability.
• 4. This is reflected in the band diagram by the donor level, which remains very close to the empty conduction band. So, with very little energy, we can get these donor electrons into the conduction band and carry out the conduction processes.

Generation of Carriers:

• 1. The process of producing free electrons and holes in pairs is known as generation off carriers.
• 2. When electrons in a valence band gain enough energy, they absorb it and move into the conduction band. The electron that has jumped into a conduction band is known as a free electron, and the location where the electron has left is known as a hole.
• 3. Similarly, two types of charge carriers (free electrons and holes) are produced.

Recombination of Carriers:

• 1. The elimination of free electrons and holes is referred to as carrier recombination.
• 2. When a free electron in the conduction band collides with a hole in the valence band, both the free electron and the hole are destroyed.

Semiconductor Junction:

• 1. A metal-semiconductor (M-S) junction is a type of electrical junction that occurs when a metal comes into close contact with a semiconductor material.
• 2. Depending on the interface properties, metal-semiconductor (M-S) junctions can behave as either Schotky barriers or Ohmic contacts.
• 3. The mismatch of the Fermi energy between metal and semiconductor material, caused by the difference in work functions, is the principle of forming different types of metal-semiconductor contacts.

Qb. Outline the construction and working of solar P-V cell with the help of suitable diagram and also discuss performance curve and conversion efficiency in terms of fill factor of the solar P-V cell.

Ans.
A. Construction of Photovoltaic Cell:

• 1. Fig. shows the construction of the silicon photovoltaic cell.
• 2. In order to allow light to easily penetrate the material, the upper surface of the cell is covered with a thin coating of p-type material.
• 3. P-type and n-type materials are encircled by metal rings, which serve as their positive and negative output terminals, respectively.

B. Working of Photovoltaic Cell:

• 1. The semiconductor material’s electrons begin to emit when light is absorbed by the substance.
• 2. This happens because the light consists of small energy particles called photons.
• 3. When electrons absorb photons, they gain energy and begin to move into the material.
• 4. Because of the effect of an electric field, particles only move in one direction and generate current.

C. Performance Curve:

• 1. A PV device’s V-I characteristics are a non-linear graph of the current and voltage generated by the PV module as shown Fig.
• 2. Different graphs have been plotted for various temperature levels.
• 3. Maximum power points have also been depicted to represent the maximum power that can be drawn from a PV device.
• 4. The maximum power line is made up of these maximum power points (MPL).
• 5. MPL denotes the maximum power point tracker’s track or path (MPPT).

D. Conversion Efficiency:

• 1. Fill factor is the ratio of maximum power to theoretical power.
• 2. The efficiency of a solar pv panel is the ratio of the maximum power that it can generate under standard testing conditions to the input power.
• 3. Conversion efficiency on form of fill factor can be given as,
• Where, U_oc = Open circuit voltage,
                 I_sx = Short circuit current, and
                P_in = Input Power.

6. Attempt any one part of the following:                                                       (10 x 1 = 10)

a. Illustrate the concept of:
A. Fluid dynamics in wind energy conversion.
B. Betz law to receive maximum energy.
C. Effect of number of rotor blades on performance efficiency.

Ans. A. Fluid dynamics in wind energy conversion: The fundamental principle of wind energy is to convert wind kinetic energy into rotational motion in order to power an electric generator.

B. Betz Law:

• 1. Betz’s law specifies the maximum power that can be extracted from the wind, regardless of wind turbine design in open flow.
• 2. The law is derived from mass conservation principles and flows through an idealised actuator momentum of the air stream, oc disc that extracts energy from the wind stream.
• 3. No turbine can capture more than 16/27 (59.3%) of the kinetic energy in wind, according to Betz’s law. Betz’s coefficient is the factor 16/27 (0.593).
• 4. Practical utility scale wind turbines achieve at peak 75-80 % of the Betz limit
• 5. An open disc actuator is used to calculate the Betz limit. More energy can be extracted if a diffuser is used to collect additional wind flow and direct it through the turbine, but the limit still applies to the cross-section of the entire structure.

C. Effect of number of rotor blades on performance efficiency:

a. Diameter of the Rotor: The rotor’s diameter is determined by the operating wind speed and the rated power output.

b. Choice of the Number of Blades:

• 1. It is obvious that the efficiency of wind energy extraction is dependent on the number of blades used.
• 2. If the blades are so close to each other or rotate so quickly that each blade moves into the turbulent air created by the previous blade, there will be little power extraction.
• 3. It will also be less than optimum if the blades are so far apart or move so slowly that much of the air stream passes through the wind turbine without interacting with a blade.
• 4. Thus, the choice of the number of blades should depend on the TSR (tip speed ratio).

c. Choice of the Blade Profile and Material:

• 1. The blade of a low TSR water-pumping wind mill is typically a flat metallic plate.
• 2. In some cases, it is a simple, circularly curved metallic sheet that produces aerofoil-like characteristics while maintaining uniform thickness throughout the blade. Because of their low rigidity, these blades must be structurally supported by a circular metallic frame.

Qb. Analyze the construction, working and limitations of geothermal power plant with the help of diagram.

Ans.
A. Construction and working of Geothermal Power:

a. Vapour Dominated Power Plant:

• 1. Steam is extracted from geothermal wells, passed through a separator to remove particulate content, and then flows directly to a steam turbine in a vapour-dominated power plant.
• 2. Steam then powers the turbine and generator at temperatures around 245 °C and pressures of 7 bar, which are lower than in conventional steam cycle plants.
• 3. Thus, the efficiency of geothermal plants is low, i.e., about 20%.
• 4. The turbine’s exhaust steam passes through a condenser, and the resulting water circulates through the cooling tower.
• 5. It increases turbine efficiency and reduces environmental pollution caused by direct steam release into the atmosphere.
• 6. To ensure continuous supply, waste water from the cooling tower sump is re-injected into the geothermal well.

b. Liquid Domination Power Plants:

• 1. These plants are also known as wet steam plants because they produce wet steam, which is a high-pressure mixture of hot water and steam.
• 2. There are two type of liquid dominated power plants:

i. Flashed Steam System:

• 1. For high temperature mixtures of geothermal brine and steam with low dissolved impurities, a flashed system is preferred.
• 
• 2. Geothermal fluid (a brine-and-steam mixture) flows through an Im geothermal power plant. In a flash chamber, a large portion of the fluid is converted to steam.
• 3. To generate electricity, dry saturated steam is passed through the turbine and generator.
• 4. Hot brine from the flash chamber and turbine discharges from the condenser are re-injected into the ground, ensuring a constant supply of geothermal fluid from the well.

ii. Binary Cycle System :

• 1. When the geothermal fluid is hot water with a temperature less than 100 °C, a binary cycle is used.
• 2. In a thermodynamic closed Rankine cycle, this plant uses a low boiling point working fluid.
• 3. Hot brine from an underground reservoir is pumped back into the ground via a heat exchanger.
• 4. Hot brine transfers its heat to the organic fluid in a heat exchanger, converting it to a superheated vapour that is used in a standard closed Rankine cycle.

B. Limitations of Geothermal Power Plant:

• 1. It has environmental concerns.
• 2. It involves high initial investment.
• 3. Only suitable to particular region.

7. Attempt any one part of the following:                                                     (10 x 1 = 10)

Qa. Summarize the global warming feature and focus the impacts of this phenomena on the disturbance to the sustainability of environment.

Ans.
A. Global Warming Feature:

• 1. A general increase in the earth’s average temperature, known as global warming, is a phenomenon of climate change that has a long-term impact on the weather patterns and eco-systems.
• 2. It is closely related to how much more greenhouse gases are present in our atmosphere, which exacerbates the greenhouse effect.
• 3. Global warming is the gradual warming of Earth’s climate system since the pre-industrial era (between 1850 and 1900), which is attributed to human activity, particularly the burning of fossil fuels, which raises the amounts of greenhouse gases that trap heat in Earth’s atmosphere.
• 4. The phrase is frequently used synonymously with the phrase “climate change,” despite the latter referring to both naturally occurring warming and its effects on our planet.

B. Impacts of Global Warming on Disturbance to Sustainability of Environment:

• 1. Sea level running.
• 2. Altered precipitation pattern.
• 3. Change in soil moisture content.
• 4. Increase in some extreme weather.
• 5. More load more droughts.
• 6. Alteration of natural climate cycle the EL Nino.
• 7. Change in the species ranges.
• 8. Change in the ocean direction.

Qb. Integrate the concept of

A. Energy conversion and various principles involved in energy conservation.
B. Energy conservation in illuminating systems.
C. LEED ratings.
D. Concept of green building and green architectures.

Ans.
A. Energy conversion and various principles involved in energy conservation:

• 1. Energy conservation refers to methods of reducing energy consumption through waste elimination and efficiency promotion.
• 2. Energy conservation is a critical component of energy management.
• 3. We can reduce our energy consumption by implementing various energy conservation strategies, such as making better use of technology and avoiding energy waste.
• 4. The various principles involved in energy conservations are:
  • i. Optimal control,
  • ii. Optimize capacity,
  • iii. Optimize load,
  • iv. Use efficient processes,
  • v. Reduce losses,
  • vi. Energy containment,
  • vii. Examine energy conservation opportunities, and
  • viii. Energy storage facilities.

B. Energy Conservation in Illuminating Systems:

Energy conservation in illuminating system can be done by following ways:

• 1. Modify lighting layout to meet the need.
• 2. Select light colours for interiors.
• 3. Install energy efficient lamps.
• 4. Provide timer switches or pu controls.
• 5. Switch off when not required.
• 6. Make maximum use of natural light.

C. LEED Ratings:

• 1. LEED (Leadership in Energy and Environmental Design) is an internationally recognised green building certification system that provides third-party verification that a building or community was designed and built using strategies to improve performance across all the metrics that matter most: energy savings, water efficiency, CO emissions reduction, improved indoor environmental quality, and sensitivity to their impacts.
• 2. LEED provides a concise framework for building owners and operators to identify and implement practical and measurable green building design, construction, operations, and maintenance solutions.
• 3. It is applicable throughout the building lifecycle, including design and construction, operations and maintenance, and major retrofit.
• 4. LEED provides a framework for sustainability in the design, construction, operation, and maintenance of new and existing buildings.
• 5. LEED uses a point system to evaluate the design and construction of green buildings.
• 6. The system is divided into five fundamental categories: sustainable sites, water efficiency, energy and atmosphere, materials and resources, and indoor environmental quality.

D. a. Concept of Green Building: A green building is one that, through its design, construction, or operation, reduces or eliminates negative impacts on our climate and natural environment while also having the potential to create positive impacts. Green buildings protect valuable natural resources while also improving our quality of life.

b. Green Architecture:

• 1. Green architecture is a long-term approach to green building design. It consists of both design and construction with the environment in mind.
• 2. Green architects generally work with the fundamental concepts of building an energy-efficient, environmentally friendly home.
• 3. Both the design and the construction of a building can make it truly sustainable and green, and the architect should pay close attention to both aspects of the process.
• 4. Green architecture can be wonderful examples of humans living in harmony with the environment.
• 5. There are opportunities to design beautiful, energy-efficient, and eco-friendly homes and workplaces that demonstrate our human ability to adapt to and peacefully live within the natural world’s ecology.
• 6. The natural ecology of the planet should serve as the macro model for architects when designing green buildings.
• 7. Architecture can be modelled after the solar system to mimic the natural green environment, creating a new building or adapting an existing building that is both eco-friendly in terms of materials used and space occupied, and energy efficient, including solar technology.

Energy science and engineering Important Links:

AKTU Important Links | Btech Syllabus

Important Links-Btech (AKTU) | Energy science and engineering Syllabus