Ae4010 Research Methodology- Economical Energy Assessment Answers

Answer:

Renewable and economical energy is the current focus of the world, since it can convert the energy from varied renewable energy sources into another form, the electrical energy. Renewable energy is collected from the resources that can be renewable, without result of any harm to the environment and so to the human kind. The renewable resources are expected to be replenished naturally, like rain, wind, waves, geothermal energy, tides, sunlight etc.

Moving one step ahead, the project is intended to use the waste resources that are going to create the water and environmental pollutions and covert them into electrical energy. Here, the variation is that the electrical energy that is going to be converted from the flow of wastewater from the household is of lower level, because of the small scale project (Sørensen, 2004). The electrical energy will be generated that is enough for the household requirement of electricity.

There are three kinds of renewable energy created, hydro, solar and wind electricity, primarily. Among these kinds, geothermal and hydro-electricity are the cheapest or less expensive ways of electricity generation. When the conventional methods are considered, small hydro and run-of-the-river methods of hydroelectricity are followed, towards less hassle of not setting up larger reservoir.

The electrical energy that is going to be created from the flow of waste water from the household is expected to generate through hydroelectricity, in this project (Wehrli, 2011).

The current share of hydroelectricity in the renewable energy is 3.9% of hydro electricity, in terms of electricity consumption. The hydro electricity is usually generated in larger scale, by employing the large dams, etc. In terms of hydropower, total 16.6% of electricity is generated, in the world (Sørensen, 2004).

Hydropower can be generated by using water, since density of water is 800 times more than that of the air. So, water, even when it flows, from a moderate sea swell or in a small stream can enable the generation of energy. Largest amount of hydroelectricity is produced by China, having about 45,000 installations of hydro power in smaller scale.

Energy can be generated by using water in different ways, as the following (WI, 2012).

1. Reservoirs and Dams

Hydroelectric power comes from the large hydroelectric reservoirs and dams construction, historically, in the world, since they can produce the energy in larger scale. Such generation has been still popular in the third world countries with the largest dams in descending are Three Gorges Dam, Itaipu Dam and Praguay. Power generated from this larger scale method is of a few giga watts.

1. Rivers

Rivers have been the good source of energy through small hydro systems, with the installations of hydroelectric power and they can produce the power, up to 50 Mega Watts. These systems are employed using larger rives with impact development and small rivers used directly. Such systems have the capability to generate up to 30 mega watts of power.

1. Run-of-the-river

Plants of run of the river hydroelectricity can generate the energy, from the rivers, with no need of setting up larger reservoirs that are expensive and time consuming. It derives the energy from the river, by using the kinetic energy. Though it is a smaller set up of the installation and infrastructure, it has the ability to produce the electricity in larger amount. Examples for such systems are Chief Joseph Dam, in the US.

1. Micro Hydro

Micro hydro level installations of the hydroelectric power produce typically, up to a power of 100 kW. Such systems are used for providing the electric energy to the small community or even direct home, or may sometimes be connected to the networks of electric power. These systems stand as a source of economical energy, who cannot afford to buy sufficient fuel, especially, developing countries. They can complement the energy systems of photovoltaic solar.

5. Pico Hydro

The range of hydroelectric power generated from the pico hydro is up to 5 kW. This smaller scale method can be useful for the remote and very small communities that have smaller requirement of the electric power, such as a TV, bulbs and a fan. It makes use of the 200 to 300 watts of power. Smaller turbines with drop of 3 feet or 1 meter would be sufficient, for such hydroelectricity generation. It is also called as run-of-stream.

6. Underground

The method makes use of the natural difference of height, in between the two existing waterways, like Mountain Lake, waterfall. It makes use of the tunnel in the underground to flow water to the generating hall, from higher reservoir to the water tunnel lower point.

The pico hydro is the key point to generate the energy from the physical flow of water, wasted in domestic applications, from the household (Staff, 2004).

Production of hydropower is present in total 150 countries so far. It should be noted that the countries that have lion share of the production of electricity from the renewable resources are hydroelectric, primarily. Having digested this fact, smaller energy, in fact the electricity needed for the household appliances, could be easily generated from the waste water that flows either above the ground or flowing towards the underground. It also relieves the hassles from the tedious and expensive process of distribution of electricity, from the central electricity generation grids (Sørensen, 2004).

Advantages 

Water energy is the preferred renewable energy in the world so far, for the following advantages (Engler, 2006).

1. Water is an easily available resource to convert into the required form of energy.
2. Water is not consumed or wasted in the hydroelectricity.
3. It is not an expensive method of conversion of energy.
4. It allows distributed power generation, which is easier than the central power generation and distributing with expensive infrastructure for the same.
5. There is no waste of energy generated.
6. The method releases no harm or pollutants to environment and so to the human kind.
7. It does not allow diminishing the fossil fuel, which are less available and limited.
8. Hydropower is flexible enough, since it can be changed up and down, so easily and quickly to the dynamic changes of electricity demand.
9. High value power can be generated, because of the clean electricity produced, from hydroelectricity.
10. The average electricity cost, from the hydro station is very less, of 3 to 5 US cents for 10 megawatts, per kilowatt-hour.
11. Can produce intermittent energy
12. Lower operating labour cost
13. Low cost of construction for the dams and can be offset in shorter time.
14. Suitable for industrial applications also.
15. Reduced emissions of carbon dioxide
16. The water reservoirs can also be used as tourist attractions and water sports applications.
17. Aquaculture is possible in the reservoirs.
18. Can provide irrigation to the agriculture support, with regular and consistent supply of water.
19. Floods can be controlled with hydro dams, otherwise would affect the population that lives in the downstream.
20. Loss of land damage of the ecosystem
21. Evaporation of water, though it is very less.
22. Shortage of siltation and flow
23. Emissions of methane
24. Relocation of the people, locally
25. Risks of failure

Power Calculation 

At the hydroelectric station, the total electric power produced,

P = hrgk. (Saleh et al, 2016)

Here, ρ = water density,

r = rate of flow in m³ per second

h = height in meters

k = value ranges from 0 to 1, coefficient of efficiency

g = acceleration due to gravity, which is equal to 9.8 m/s²

and P = total power in watts

The total production of electric energy annually is based on the water supply that is available. The rate of water flow is varied at the rate of 10:1, usually, in a year.

Research Questions

The following research questions are considered, in this project.

1. Can the smaller size water flow generate the electricity?
2. Can the electricity generated from the water flow, released from the household and domestic water usage tasks, be useful for smaller or household electricity applications?
3. Can the small scale electricity generation be able to drive the appliances used in the household, such as the refrigerator, fan or can it drive the Air Conditioner, etc.?
4. Can the system be scaled up, to increase the supply to more households?

Theoretical Content/Methodology

Energy Storage

Energy storage can be done with various methods of storing the electrical energy. It is done either on or off the electrical power grid, for larger scale. Here, in this context it is not a hassle, as the energy generated can be directly used by the household, to which the energy is passed to it (Du & Robertson, 2017).

Turbine 

A turbine is designed to convert to water potential energy from kinetic energy, and is called as a rotary machine. They are used for the generation of the electric power. It has a component of motion that enables the turbine to become to in a smaller size. It can increase the capacity of water, by processing more water (Khalilpour & Vassallo, 2015).

A turbine consists of blades that enable the mechanism of rotation, creating mechanical energy that would be converted to the electrical energy. 

Operation 

Water flow is directed to the turbine blades and force is created on the blades. Then the runner starts spinning and enables through the distance, with the ‘work’ created. Finally, energy is transferred to the turbine from the flow of water.

Classification 

Turbines are classified as impulse and reaction turbines (Brass et al, 2012).

1. Impulse Turbine

Impulse turbine has its function based on the change of water jet velocity. The curved blades of the turbine are pushed by the jet and change the flow direction. Then the force is created on the blades of the turbine. The fluid pressure that flows over the rotating blades, in the impuse turbine is constant and the so the all the output of work, because of the fluid’s kinetic energy change.

1. Reaction Turbine

It works on the Newton’s third law. The turbine has its function, based on the reaction created by the pressure of the turbine, in moving blades and fixed bladed. It has the applications in the larger power plants.

So, when the turbine is installed, the total power with the turbine, P would be,

P = ρ *η*g*q*h

Where, η is the efficiency of the turbine,

ρ = water density, in kg per m3

q = rate of flow in m3 per second

h = head in meters and is equal to the sum of velocity head pressure head

g = gravity acceleration, a constant value of 9.81 meter per square second

(Redfield, n.d)

Speed 

Runway Speed

The water turbine runaway speed is the maximum speed that is measured at full flow with no shaft load. It is the maximum tolerable speed, with which the turbine can survive with maximum possible mechanical forces. So, the runaway speed is usually specified by the speed rating, given by the manufacturer (Spicher & Thomas, 2013).

Specific Speed 

Turbine needs specific speed to be created and it should match to the specific applications. The shape of the turbine is characterized by the specific speed, ns. Usually, the scale of the design of the new turbine is considered, from the existing or known performance of the design. The specific speed of the turbine is considered as the matching factor, between turbine type and the hydro site. It is defined as the speed, with which the turning of the turbine is done for a Q, a specific discharge, with a unit head and so it enables unit power of production.

The speed of the turbine is varied based on the scaling. So, usually the maximum speed of the turbine speed varies from 20,000 to 50,000 rpm, for larger turbine and for the smaller scale hydroelectricity, from small water flow, it takes only a few hundreds of rotations per minute.

Shape 

The water turbine blades have certain kind of precise shape. It is the basis for the water supply pressure function and impeller type. Turbine blades are in a rotating shape, so that when the water falls over the curve of the blade, it enables the total structure, with which it is leveraged, to move, as a whole. And this is the key point in shaping the blades of the turbine (Adhikary, 2013).

Usually, blades have the curved shape and are made with the material that have higher strength and have corrosion resistance. Usually, austenitic steel allows are used, in which chromium is present from 17% to 20%, so that the film stability can be increased, improving the resistance of aqueous corrosion. Martensitic stainless steels are currently used, as they have more strength, by 2 times than the austenitic stainless steel. Selection of the blade is usually based on the strength and corrosion resistance. Another important factor is the low weight that allows the blades to move more easily.

Turbine generator is the key unit that chosen and employed, based on the scaling of the project. So, for the larger scale hydroelectricity system, it takes complex and high rated turbine generator and small scale system takes low rated and less complex turbine generator (Padhy & Senapati, 2015).

So, based on the generating methods, the total system of hydroelectricity system can be classified as the following.

1. Conventional method of hydroelectricity
2. Pumped storage method
3. Run of the river method
4. Tidal method

The experiment is proposed and planned conducted to generate very small scale, yet sufficient for the household electrical energy applications. The objective is to design and implement economical electricity generation.

The project is intended to develop a pico hydropower system. The experimental setup is going to have the following block diagram (Gummer & John, 2009).

Turbine

The turbine is expected to be set, as the following diagram, with the turbine blades.

The experimental setup and the overall small scale hydropower system are going to have the following units in it.

1. Turbine, for generation of electricity and it includes the generator, runner and nozzles
2. Dump load, for absorbing the surplus energy
3. Penstock, or pipeline, for carrying the water towards the turbine
4. Diversion and intake screen, for directing the into the channel or pipe, from the river or stream
5. Batteries, for storing the energy of turbine
6. Distributor or transmitter, for delivering the energy to its final user

The experiment is set up for a household with an expected arrangement of wastewater flowing towards steep downfall. The intake or weir is located on the starting point of the channel to convey water. Penstock is placed on the steep slope that ends at the turbine.

The mechanical energy is converted then to the electrical energy and it would be connected to the appliances of the end-user, in the household (Whitakar, 2006).

Results, Outcome and Relevance

The final results expected and obtained from the generation of electricity from the household wastewater, are the following.

1. A few kilowatt-hours can be generated.
2. The wastewater from the household can be sufficient, to generate the kilowatt power.
3. Household electrical needs can be fulfilled.
4. The needs are fulfilled, with no need for the external or conventional electricity.
5. The final resulting hydro power system can be completed within a hundred US dollars

Project planning is done, as given in the following work breakdown structure.

Table: Work breakdown structure 

Conclusions

The project has been intended and commenced with the intent of following and encouraging the renewable energy and self sustainability, without the need to rely on the conventional energy. The wastewater, which would result in the water pollution in the environment, is intended to use as a renewable resource of generating the electricity that can make a household appliances to drive. The project follows the hydroelectricity method and methodology to generate sufficient power for the household appliances to drive and run. Pico hydroelectricity is the key method used for this small scale generation of the electricity.

References

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