Archimedes Screw Turbine

Generating sustainable energy is currently one of the world's most pressing issues. As fossil fuel resources dwindle, CO2 levels rise, pollution levels rise, global warming worsens, and scientists are scrambling to develop new sources of energy. Limitations on fossil fuels and concerns about sustain

Project Title

Archimedes Screw Turbine

Project Area of Specialization

Mechanical Engineering

Project Summary

Generating sustainable energy is currently one of the world's most pressing issues. As fossil fuel resources dwindle, CO2 levels rise, pollution levels rise, global warming worsens, and scientists are scrambling to develop new sources of energy. Limitations on fossil fuels and concerns about sustainability need a shift in how energy is generated and consumed. Solar, wind, geothermal, and hydropower are all examples of renewable energy resources that account for 22.8 percent of global electricity output.

Hydropower facilities remain a vital renewable energy resource, despite the fact that large-scale hydropower potential has already been exhausted. Small rivers, irrigation systems, water supply networks, sewerage networks, cooling systems, and other small-scale hydropower producing opportunities abound.

Small-scale water turbines come in a variety of shapes and sizes, including AST, Kaplan, and Francis. Our research focuses on ASTs, which have typically been used to pump water from a lower to a higher level or to move water in vertical or horizontal planes. ASTs provide more energy (15%) at a reduced cost, in addition to being ecologically and fish-friendly structures for power generating with simple installation and inexpensive civil works (10 percent) ASTs can also be utilized with other energy sources, such as the sun.

• Archimedes screws are small hydro systems that, even when put alongside existing tiny dams/weirs, provide only a little impoundment and, in many cases, no visible impoundment at all. As a result, there is no flooding of animals or nearby land, and the water temperature rises very slightly.
• Because Archimedes screw turbines are run-of-river systems, water flow timing and variance are unaffected. Archimedes screw turbines do not need a reservoir to "store" water.
• Archimedes screw systems generate hydropower at a low cost. This implies that modest dams/weirs are once again helpful valuable assets, as they have been historical, as we clean up to our air, regenerate our economy, and lessen our dependency on foreign oil.
• Archimedes screw systems don't block sediment, woody debris, or nutrient circulation. Because half of a screw's diameter is above water level and the other half is below it, the Archimedes screw system's intake expanded below the crest of any small dam/weir, allowing for the motion and passage of sediment, woody debris, and nutrients that would otherwise pile up behind the small dam or weir.  There is no fine screening on it.
• Archimedes screw devices provide downstream fish passage at minor dam sites, and if environmental authorities choose, they can be combined with fish channels to restore upstream fish flow as well.

Project Objectives

According to a survey in 2014, the electricity situation in Pakistan, especially in the rural and remote areas about 35% of population lacked access to electricity. Electricity is either present or there are numerous power disruptions. For a developing country, electricity is one of the prime factors that can measure the development level of a country in terms of energy resources. It helps to increase productivity in agriculture and labor, gives access to communications (TV, Radio), improved health conditions, improves lighting conditions.

A thermal power plant is a type of power plant that transforms heat energy into electricity. Unfortunately, the thermal power plant has significant environmental, soil, and air pollution, as well as a variety of social consequences. The thermal power plant is also believed to emit a lot of mercury and produce a lot of fly ash, both of which are bad for the environment. These plants take a lot of water as well. As a result of burning fossil fuels, thermal power plants are known to generate significant amounts of greenhouse gases and ash.

As a result, a suitable method of converting energy into electrical energy, which can be easily produced and supplied for that particular location, must be chosen.

Small hydropower plants are ideal in rural and distant areas since they are less expensive to install and take less time to complete.

To develop a small hydroelectric power plants that can be easily installed even in low head sites and to provide electricity to those areas that are unable to connect with national grid station and for small communities.

It should provide a clean and renewable source of electricity that is less harmful to wildlife, particularly fish, than other hydropower sources.

Its maintenance is very low as compared to other hydropower plants.

In terms of sustainable development, it should provide several economic, social, and environmental advantages that make it a significant option for providing sustainable hydropower development. In Pakistan alone, there are a lot of sites with potential for low head hydro, encompassing sluice gates, irrigation canals, drinking water pressure release valves, and metropolitan wastewater outlets, as well as in many rivers.

The overall aim of the project is to design and create a device for power generation which could offer unique advantages to investors and governmental bodies to increase the likelihood of an increased number of these small heads projects in and around Pakistan.

Project Implementation Method

Implementation method

Assessments of electricity needs:

1. Calculate the needed power and forecast the potential future demand variations.
2. Determine whether or not the power plant would be grid-connected or off-grid.
3. If the AST powerplant is to be used off-grid, it is necessary to:

• When making design decisions, compare the value of steady baseload power vs maximizing the powerplant's yearly production.
• Define and take into account the required voltages and/or currents.

For the site assessment:

1. Permitting needs, access limits, and water usage restrictions should all be considered.
2. The river's flow duration curve should be used to determine the baseload and other choices for the powerplant's operation. This data also aids decision-making throughout the plant design phase.
3. Ecological evaluations should be conducted, as well as the water requirements of other users or ecological services. The needed flow for fish passage or the installation of a fish ladder, for example, should be determined.
4. The site of a feasible project should be chosen based on the following factors:

• Construction, operation, and maintenance are all accessible. This is critical for civil construction and screw installation, especially for bigger power plants with huge and unwieldy screw(s) that require crane installation.
• Concerns about geotechnical stability and appropriateness for plant foundations.
• Routing of supply and output channels.
• There might be conflicts with concerns for another site for usage.

In-plant design assessment:

The type of plant should be selected based on previous assessments:

1. A single-speed plant might be regarded as a simpler and more efficient solution for continuous flow. These systems have a cheaper price/watt than variable-speed systems on average. Fixed speed screws can nevertheless make energy in a half-filled condition if the incoming stream is not enough to start filling the screw at its working velocity.
2. When there is an extra flow that would be used to create additional power from an available flow when the flow fluctuates, changeable speed screws are advised. The fundamental reason why is because, while running ASTs at full capacity is perhaps the most technically efficient action, that doesn't always result in the most total energy output.

Benefits of the Project

In recent years, it has been shown that using screw turbines at a small hydropower plant (SHPP) may provide far more benefits than using other types of turbines such as Kaplan, Francis, Propeller, or Crossflow. When compared to Kaplan turbines, the installation costs of a hydraulic system using Archimedes screw turbines are significantly cheaper. According to British experts, a hydraulic turbine system using Archimedes' screw generates 15% more energy and costs 10% less than a Kaplan system. Screw turbines are far more efficient than Kaplan turbines, both in terms of energy output and, more importantly, in terms of cost, hence their deployment in numerous places would be suggested.

The benefits of implementing screw turbines are:

• The hydraulic system's efficiency is unaffected by changes in river flow or water level.
• Fish do not suffer from the implementation of such a hydraulic system, according to studies; they may safely traverse from one end of the turbine to the other.
• Because of the turbine's screw design and operation, branches and other debris may flow through without compromising the system's functionality, lowering maintenance expenses.
• A system of this type can last up to 40 years. Commercially appealing, practical and efficient, and non-clogging.
• They have no negative environmental impact, and the investment has a relatively short amortization period.
• The expense of maintenance is low.
• The installation is completed.
• The time required by such a system is minimal.
• The system is extremely durable and long-lasting.
• Due to the modest size and beauty of the screwdriver mechanism, it blends in nicely with the scenery.
• By utilizing a river's hydroelectric potential, fossil fuels are conserved.
• In comparison to other turbines and waterwheels, it is quite cost-effective.
• Compared to other turbines and water wheels, it has higher efficiency at lower flows.
• Installing, using, and maintaining it is relatively straightforward.
• Slower rotational speeds mean longer bearing life.
• Using common three-phase generators and other readily accessible components, the system is sturdy and dependable.
• Because there are no tiny nozzles, the ability to manage particles without fine screening is possible.
• Fish-friendly, with the ability to securely pass fish downstream
• it may be operated with heads as low as 1 meter and flow rates as low as 100 liters per second.

Technical Details of Final Deliverable

Water enters the screw at the top, and its weight pushes against the helical flights, allowing the water to fall to the lower level and rotate the screw. This rotational energy can then be pulled out by an electrical generator coupled to the main shaft of the screw. The Archimedean screw turbine is used on rivers with a low head (0.1 m to 10 m) and low flows (0.01 m3s  to 10 m3s ). The turbine is regarded to be aquatic wildlife-friendly due to its structure and moderate movement of the turbine blades. Its maintenance cost will also be very low and it does not need maintenance for a long time due to its simple geometry.

The length of the shaft of the screw is 700 mm with the blades of screw portion is of 550 mm and the pitch is about 137.5 mm. The starting of blades is from 75 mm from the one end of the shaft. The screw is double-bladed in order to improve the efficiency of the turbine. The bed of the screw has very little clearance in order to increase the velocity of the Archimedean screw. A compound belt and pulley system are used to increase the speed in order to rotate the dynamo motor to produce electricity. The screw turbine has an adjustable frame in order to change the angle of inclination to get maximum speed.

We have performed the static analysis in Solidworks Simulation on the Archimedean screw in which we have used aluminum alloys as a material for the blade of the screw. We have noticed that our design will remain safe if a force of 300 N will apply to the screw blade. We have also performed a test for the torque. By applying a torque of 21 N-m our blade will show results within the safe limits.

We have performed the Solidworks Flow Simulation on the 1-bladed, 2-bladed, & 3-bladed Archimedean screws and compared their results. Inflow simulation, with a rotating shaft and having an external flow on the blades with the same input velocities (1 m/s) on the three blades using X-axis as reference axis & by enabling gravity and not applying any boundary condition from the flow simulation menu. It gives the velocities of 1.178 m/s 1.345 m/s and 1.493 m/s for 1, 2, & 3 –bladed Archimedean screws respectively. According to our analysis, its performance is directly proportional to the number of blades. 2-bladed screw shows satisfactory results as compared to 1-bladed as well as 3-bladed. However, 3-bladed shows some better performance as compared to 2-bladed but to add a third blade becomes complex to fabricate and it also increases the cost of fabrication.

Final Deliverable of the Project

Hardware System

Core Industry

Energy

Other Industries

Manufacturing , Health

Core Technology

Clean Tech

Other Technologies

Others

Sustainable Development Goals

Good Health and Well-Being for People, Affordable and Clean Energy, Decent Work and Economic Growth, Sustainable Cities and Communities, Climate Action, Life Below Water

Required Resources

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