Solution NCES, RTU PAPER 2019-20Q.1.a) What are the reason of tide and how it can be used for power production.Draw the layout of tidal power plant and name various components.

A.1a) Gravitational pull of the sun and moon and the pull of the centrifugalforce of rotation of the earth-moon system.

When a landmass lines up with the earth-moon system, the water around it is athigh tide.

When a landmass is at 90 ͦ to the earth-moon system, the water around it is atlow tide.

There are two high tides and two low tides during each period of rotation of theearth.

Tidal power utilizes the twice-daily variation in sea level caused primarily by thegravitational effect of the Moon and, to a lesser extent the Sun on the world'soceans. The Earth's rotation is also a factor in the production of tides

The generation of electricity from tides is very similar to hydroelectricgeneration, except that water can flow in both directions and this must beconsidered in the development of the generators.The simplest generating system for tidal plants, known as an ebb generatingsystem, involves a dam, known as a barrage across an estuary.Sluice gates on the barrage allow the tidal basin to fill on the incoming high tidesand to exit through the turbine system on the outgoing tide (known as the ebbtide).Alternatively, flood-generating systems, which generate power from theincoming tide are possible, but are less favored than ebb generating systems.Tidal power generation have following three main components: -

• Basin or Dam or Barrage to Form Pool• Sluice Gate- Way from Basin to Sea or Sea to Basin• Power House

Q1b) Explain the environmental effect of tidal power.

A1b) Tidal Changes The construction of a tidal barrage in an estuary will change the tidal level in

the basin. This change is difficult to predict, and can result in a lowering orraising of the tidal level.

This change will also have a marked effect on the sedimentation and purity ofthe water within the basin. In addition, navigation and recreation can beaffected as a result of a sea depth change due to increased sedimentationwithin the basin.

A raising of the tidal level could result in the flooding of the shoreline, whichcould have an effect on the local marine food chain.

Ecological Changes Potentially the largest disadvantage of tidal power is the effect a tidal station

has on the plants and animals which live within the estuary. As very few tidalbarrages have been built, very little is understood about the full impact of tidalpower systems on the local environment. What has been concluded is that the

effect due to a tidal barrage is highly dependent upon the local geography andmarine ecosystem.

Wales have been caught in tidal generators. Fish may move through sluices safely, but when these are closed, fish will

seek out turbines and attempt to swim through them. Also, some fish will beunable to escape the water speed near a turbine and will be sucked through.

(OR)Q1. Differentiate conventional and non-conventional energy sources.

A.1. Conventional sources of energy:

Conventional sources of energy are the natural energy resources which are presentin a limited quantity and are being used for a long time. They are called non-renewable sources as once they are depleted, they cannot be generated at the speedwhich can sustain its consumption rate. They are formed from decaying matter overhundreds of millions of years.

These resources have been depleted to a great extent due to their continuousexploitation. It is believed that the deposits of petroleum in our country will beexhausted within few decades and the coal reserves can last for a hundred moreyears. Some common examples of conventional sources of energy include coal,petroleum, natural gas and electricity.

Non-conventional sources of energy:

Non-conventional sources of energy are the energy sources which are continuouslyreplenished by natural processes. These cannot be exhausted easily, can be generatedconstantly so can be used again and again, e.g. solar energy, wind energy, tidalenergy, biomass energy and geothermal energy etc. The energy obtained from non-conventional sources is known as non-conventional energy. These sources do notpollute the environment and do not require heavy expenditure. They are calledrenewable resources as they can be replaced through natural processes at a rate equalto or greater than the rate at which they are consumed.

Comparison Chart

Basis Conventional Sources Non-Conventional Sources

Meaning Conventional sources of energyare the sources that arecommonly in use since longtime.

Non-conventional sources ofenergy refer to the sources that areidentified few decades ago.

Exhaustible They can be exhausted due toover consumption.

They cannot be exhausted.

Pollution They pollute environment, on alarge scale and adds to globalwarming.

They are environment friendlysources, pollution free.

Use They are primarily used forindustrial and commercialpurposes.

They are mainly used fordomestic purposes.

Expense Costly. Comparatively less expensive.

Q.2a) How solar radiation on tilted surface can be calculated. Discussmathematical used for same.The power incident on a PV module depends not only on the power contained in thesunlight, but also on the angle between the module and the sun. When the absorbingsurface and the sunlight are perpendicular to each other, the power density on thesurface is equal to that of the sunlight (in other words, the power density will alwaysbe at its maximum when the PV module is perpendicular to the sun). However, asthe angle between the sun and a fixed surface is continually changing, the powerdensity on a fixed PV module is less than that of the incident sunlight.

The amount of solar radiation incident on a tilted module surface is the componentof the incident solar radiation which is perpendicular to the module surface.

whereα is the elevation angle; andβ is the tilt angle of the module measured from the horizontal.

The elevation angle has been previously given as:

where φ is the latitude; andδ is the declination angle previously given as:

where d is the day of the year

Q2.b) What are solar energy collectors and how do they function ,explain varioustype of flat and concentrating collectors.FLAT PLATE COLLECTORS

It is an energy conversion device that absorb solar radiation and transfer theenergy to fluid passing through it.

It collects both direct and diffuse components of radiation.

It is used for both air and water heating.

A metallic flat absorber plat having high thermal conductivity of material copper,aluminum, thickness 0.5 to 1mm, having black surface.

Heat transfer medium to carry water, solder above this plat having dia. 1-1.25mm.

A transparent toughened glass to cover, this also reduce convection andradiation losses, having thickness 5mm.

Fiber insulation at bottom.

Container to house whole assembly, made of fiber glass or metallic sheet.

CONCENTRATING COLLECTORS

The concentrating solar power system (CSP) uses lenses or mirrors to focus sunlightinto a sharp beam with the help of concentrating solar collectors. This powerful beamis next focused on a small receiver to heat a fluid to a high temperature.The hot fluid is then used to generate steam that drives a steam turbine coupled toan electrical generator.

Various types of concentrating solar collectors are as under:

• Parabolic trough collector.• Power tower receiver.• Parabolic dish collector.• Fresnel lens collector.

Q2a) Describe with neat sketch the working of solar water heating system with back upsupport used in hostel.

A solar water heater is a device that captures sunlight to heat water. It can be aneconomical way to generate hot water. A solar heater not only enablessubstantial energy savings as solar power is free in contrast to natural gas or fuel oil.Moreover, it is a way to produce hot water for sanitary use throughout theyear without emitting any CO2.

The sun's thermal energy heats the fluid in the solar collectors. Then, this fluidpasses through a heat exchanger in the storage tank, transferring the heat tothe water. ... Closed-loop, or indirect, systems use a non-freezing liquid totransfer heat from the sun to water in a storage tank.

Q2b) Explain the following term related to solar radiation geometry. Declinationangle, hour angle, inclination angle, zenith angle, latitude angle, solar azimuth anglesurface azimuth angle and angle of incidence.

Ans 2b) Declination. It is angle subtended by line joining the center of the earth andthe sun its projection on earth equilateral plane.

Declination, δ The solar declination is the angular distance of the sun's rays north (orsouth) of the equator, north declination designated as positive. It is the angle betweenthe sun ‐ earth center line and the projection of this line on the equatorial plane. Thedeclination angle ranges from 0o at the spring equinox, to +23.45o at the summersolstice, to 0o at the fall equinox, to ‐23.45o at the winter solstice.

The hour angle h, of a point on the earth's surface is defined as the angle through whichthe earth would turn to bring the meridian of the point directly under the sun. • Thehour angle at local solar noon is zero, with each 360/24 or 15 degrees of longitudeequivalent to one hour, afternoon hours being designated as positive

Solar Altitude Angle, α

The solar altitude angle is the angle between the sun's rays and a horizontal plane asshown in previous figure. It is related to the Solar Zenith angle Φ, being thecomplimentary angle between the sun's rays and the vertical. Thus: Φ+α = π/2= 90°• The mathematical expression for the solar altitude angle is: sin(α) = cos(Φ) =sin(L) sin(δ)+cos(L) cos(δ) cos(h)

Solar Azimuth Angle, z The solar azimuth angle z is the angle of the sun's raysmeasured in the horizontal plane from due south (true south); westward is designatedas positive for the northern hemisphere. The mathematical expression for the solarazimuth angle is: sin(z) = cos(δ) sin(h)/cos(α)

Incidence Angle" is measured between the angle of the sun's direct rays and a linenormal (perpendicular in all directions) to the surface of the window. At high angles ofincidence, the path length of solar energy through glazing becomes very long and moreenergy is reflected and absorbed. Thus the angle of incidence has an effect on theshading coefficient and visible light transmittance of windows and skylights.

The zenith angle is the angle between the sun and the vertical. The zenith angle issimilar to the elevation angle but it is measured from the vertical rather than from thehorizontal, thus making the zenith angle = 90° - elevation.

Q3.a) What are the condition and criterion for selection of site for wind form andtype of wind machine.

A.3a)

• Maximum installed capacity (due to grid connection or PowerPurchase Agreement terms);

• Site boundary;• 'Set back’ - distances from roads, dwellings, overhead lines,

ownership boundaries and so on;• Environmental constraints;• Location of noise-sensitive dwellings, if any, and assessment criteria;• Location of visually-sensitive viewpoints, if any, and assessment

criteria;• Location of dwellings that may be affected by ‘shadow flicker’

(flickering shadows cast by rotating blades) when the sun isdirections, and assessment criteria;

• Turbine minimum spacings, as defined by the turbine supplier(these are affected by turbulence, in particular); and

• Constraints associated with communications signals, for examplemicrowave link corridors or radar.

The site selected for wind farm development need to havemany positive attributes including:

• Superior wind speed• Good road access to sites• Suitable terrain and geology for onsite access• Low population density• Minimum risk of agro-forestry operations• Close to suitable electrical grid

• Supportive land holders• Significant tourism infrastructure in place• Privately owned free hold land• Good industrial support for construction and• ongoing operations• Land use is primarily for grazing and cropping• Significant potential for revalidation

Electricity market

Existing of an electricity market for the energy generated is an important factoraffecting the economic benefits of the project. There should be energy demand inregions close to wind farms.

Environmental Considerations

The environmental sub factors that affect the site selection of a windfarm include visual impact, electromagnetic interference, wild life and endangeredspecies and noise impact.

Social Considerations

Social factors that affect the selection of a site include publicacceptance, distance from residential area and alternative land use options ofcandidate wind farm site. Public may oppose projects because of possibleenvironmental or social effects. Distance from residential area gain importance notto interfere with social life during wind farm construction or operation.

Q3b) Explain geothermal energy and preheat hybrid power plant.

Geothermal energy- energy that comes from the ground; power extractedfrom heat stored in the earth

Geo: earthThermal: heat

• Temperatures hotter than the sun’s surface are continuously produced insidethe earth by a slow decay of radioactive particles

• The most common method that scientists use to find geothermal reservoirs isdrilling a deep well and testing the temperature deep underground.

• Steam or very hot water from deep within the earth is piped to the surface andused as a heat source or to produce electricity.

PREHEAT HYBRID POWER PLANT.

The concept of hybrid geothermal utilize relative low temperature heat of GTS andhigh temperature heat from fossil fuels. Diagram is self-explanatory.Q3 Differentiate horizontal axis and Vertical axis wind turbine with neat and cleardiagram.

• A3b) These are horizontal axis and vertical axis wind turbine.• In HAWT nacelle is on top of tower and increase the tower weight, which

having difficulty to attend the fault in generator /coupling device/gearbox/rotor., whereas generator and gear box etc are in ground in VAWT,reduce the weight on tower and having easy to maintain.

• All components of both are shown in fig. below.

Q4a) Describe with neat sketch the working of laser fusion reactor

A4a) LASER FUSION REACTOR

1. With the help of pallet gun pallet are send in reactor chamber.2. In laser fusion reactor pallet is heated by laser beam.3. Pellet kept in center of reactor, these are explode like hydrogen bomb, deliver

their energy to reactor wall and cooling media.4. Laser beam is diffracted as a pulse of Nano second and hit pellet from different

direction to have thermo-nuclear reaction.5. Ablation-implosion Compression take place and the material in side the pellet (D+T)get

compressed to extremely high density due to central impulsive force and center of it getheated.

6. Micro explosion occur for about 20 Pico second and fusion reaction proceed and burn all thefuel.

7. Reaction product helium contain 20% of energy absorb in the fuel and 80% energy carriedaway by neutron absorb in lithium blanket.

8. Lase fusion reactor is driven energy amplifier.9. Amplification factor of LBR is 100 or more.10.A100 million joule of energy is produced with laser energy of 1 million joule per pulse.11.A single cavity could produce about 20MW of power.

Q4b) Briefly explain the different method of plasma confinement.

A4b) PLASMA CONFINEMENT

There are two methods for plasma confinement1. Magnetic Confinement2. Inertial Confinement

Magnetic Confinement

Inertial Confinement

OR Q4 What are requirement of nuclear fission and fusion.

Energy is needed to break apart a nucleus into its nucleons. Nuclear bindingenergy can be defined as the amount of energy needed to break one mole of nucleiinto individual nucleons. The larger the binding energy per nucleon, the stronger thenucleons are held together, and the more stable the nucleus is. Less stable atomshave lower binding energies per nucleon. In other words, it is harder to break aparta nucleus with a high binding energy than a nucleus with a low binding energy. Thebinding energy per nucleon is a function of the mass number. Light nuclei gainstability by undergoing nuclear fusion. Heavy nuclei gain stability by undergoingnuclear fission.

The initial requirement of nuclear fusion is that interacting nuclei haveenough energy to overcome force of repulsion.

The energy of nuclei can be increased by increasing the temperature.The nuclear reaction that occurs at high temperature is called thermo-nuclear reaction.

In hydrogen bomb the fusion occurs at uncontrollable way. The problem is to bring these reactions under controlled condition, so

the fusion energy release be in controlled way. In gas at high temperature, the oppositely charged nuclei and electrons

which are normally held together in a atom becomes separated witheach other, such a gas containing free positively charged nuclei andnegatively charged electron is called plasma. At fusion temp. and evenwell below hydrogen isotopes gases are plasma.IGNITIONTEMPERATURE

Plasma emits more energy in radiation than produce by fusion in fusion plasma. As temperature increases fusion energy generates more rapidly as compared toemitted

by plasma. At enough high temperature the fusion process is sustained itself once it is started, called

Ignition temperature. To achieve the ignition condition fusion energy, remain in plasma must exceed the

radiation energy. After achieving the ignition condition the fusion process continues till the fuel is

available.

The ignition temperature for D-T reaction be about 100 million degree C. In D-T reaction Helium take away 20% energy and neutron take away 80% energy

which can be utilized and absorbed outside the plasma. Hence for ignition of fusion the temperatures should be sufficient such that radiation

energy be less than 20% fusion energy.DRIVENSYSTEM In one scheme (magnetic mirror )for producing fusion energy the loss of

some charge particle is inevitable. In fusion reaction D-T ignition temperature is more than 100 million C,

this is achieved by injecting energy continuously in to the plasma andmultiplying this energy by fusion reaction.

The system of this kind is said to be driven as distinct from ignitionsystem which are self sustaining after ignition. In all the cases whetherignition occur or not minimum practical temp. for D-T fusion isconsidered roughly 100 million degree cel.

BREAK EVEN CONDITION An essential requirement for net production of nuclear fusion energy is

that the break even condition is exceeded. This condition is that the plasma be confined for sufficient time to permit

total recoverable fusion energy to balance the energy required to heat theplasma and to compensate for radiation loss.

J. D. Lawson England in 1957 showed that the energy break evencondition could be expressed as the product of, where σ is particle density and τ is confinement timeIn second.

The unit of is Sec/cm.3

is called Lawson number (confinement parameter) andminimum value for fusion energy is referred as Lawson’s Criteria. Itdepends upon type of reaction and plasma temp.

For ignition to occur the fusion energy production must exceed theamount required for breakeven. As such for D-T ignition product at

100 million-degree cel. Is thus higher at about 3*1014 .

For D-T plasma at 100 million degree cel. The breakeven condition is

calculated is around 6*10-13

sec./cm3

Q5a) Explain the process of ethanol production from cassava, what are the uses ofethanol in power sector.

Q5b) How biogas can be produced, discuss the application and mechanism involvedfor generation.

Biogas can be produced from a vast variety of raw materials (feedstocks). Thebiggest role in the biogas production process is played by microbes feeding on thebiomass.

Digestion carried out by these microorganisms creates methane, which can be usedas it is locally or upgraded to biogas equivalent to natural gas quality, enabling thetransport of the biogas over longer distances. Material containing organic nutrientsis also produced in the process, and this can be utilized for purposes such asagriculture. Different categories are as under

• Organic matter, matter from any living organism• Animal/human waste• Food crops• Grassy and woody plants• Residues from agriculture or forestry• Organic component of municipal and industrial wastes

The Top Applications of Biogas are:

• Electricity generation.

• In combined heat and power (CHP) plants.• Waste Management in agriculture.• Cooking fuel as a sustainable energy source.• Injection into a natural gas pipeline.• As a Clean Renewable Fuel for Transport Vehicles.• In Biogas Fuel Cells.

OR Q5a) What are the different factors considered for selection of biogas plantsite,

Q5b) What do you mean by pyrolysis, discuss the working of one of the mostefficient pyrolysis unit.