engineering

Engineering Contexts and ChallengesRenewable Energies: Biomass Generation

The Engineering Scenario: Biomass Energy Generation slides 2-3

The Main Branches of Engineering slide 4

The Systems Approach slides 5 -

7

Making Biogas / Energy Transformations / Mechanisms slides 8-9

Modelling solutions slide 10

Energy generation systems slide 11-

14

Presentation slide 15

Biogas Generator Extension Work slides

16-

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The Engineering Scenario.

A Scottish based distillery company plans to install a biomass generator that produces energy by burning the large amount of used grain (waste) produced in the distilling process. They want to build the biomass plant on their existing site.

Many companies are considering using renewable means to generate energy. The main reasons for this are:

• to comply with laws and regulations meant to help the environment• to improve the company’s reputation by showing they are a responsible company and

environmentally friendly• to save money by not having to buy electricity or generate electricity by other less

environmentally friendly means• to make their energy supply reliable and reuse cheap and available materials

Activity. Find out about biomass generation and, through discussion, suggest other advantages of using this form of energy generation.

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In this activity we will consider some of the engineering tasks and activities required to build an engineering ‘plant’ of this type. Once we understand how the systems work we will design and ‘model ‘some of the systems necessary to create movement and produce or convert energy.

Activities. Through group and class discussion, internet research and, where possible, by discussion with practicing engineers.1.identify the:•main branches of engineering likely to be involved in building this plant.•‘types’ of engineer responsible for each of these stages: the planning, designing, construction, testing and maintenance of the new plant2.Biofuel and biomass are forms of renewable energy generation. List four types of renewable energy sources and three fossil fuels used in electricity generation and comment on the environmental implications of each.

The main branches of engineering are shown in the following slide. Examples of engineering sub branches are included on separate slides 18-23.

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Engineering is a combination between the abstract of science and the beauty

of art (Martin Bercovici)

Activity. Consider one ‘main branch’ of engineering and the note some of the most important activities and products involved. Other engineering sub branches are included on slides18-23.

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The Systems Approach

Large engineering projects such as the biomass generator are complex. To make them easer to understand a Systems Approach is used. One feature of the systems approach is to use:

Input > > process >> output (what goes in) > (what happens inside the machine for example) > (what comes out)

From the overall system diagram engineers can then decide what sub-systems will deal with each of the inputs and which will produce each of the required outputs. This gives a clearer picture of what the complete system will look like including how the sub-systems are connected together.

Activity. For a simple system, such as the kettle – identify the inputs, processes and output.

The next slide shows some of the important inputs and outputs of the distillery. Activity. By discussing the main inputs and outputs identify some of the possible environmental impacts from such a plant. Supplementary questions on environment issues are included in extension slide 17.

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System Diagram System Diagram

Activity. By discussing the main inputs and outputs identify some of the possible environmental impacts from this plant.

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Super grain feed hopper

DistilleryBio fuel Boiler

Belt presses

Steam Turbine

Existing Boilers

Natural gas Steam

Grain cake

Electricity

Export electricity

Sub-system diagram showing biomass energy generation

AnaerobicDigester

Biogas

Used grain (waste)

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Making Biogas. The video clip shows how biogas is produced. The movement of the products around the system is controlled by various mechanisms. Activity: watch the clip and identify mechanisms used in this system.Mechanisms are used to open and close the gates and valves to allow the products to flow from one part of the system to another. The gate in the Shed is opened using an electric motor, which is connected to a mechanism known as a rack and pinion. Mechanisms change the size and direction of force produced at the output of the mechanism compared to the input force.

How it Works – Making Biogas

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• Mechanisms can also covert one type of motion to another. • Electric motors produce what is known as rotary motion at their output shaft. As

you saw in the video clip the gate has to move in a straight line up and down. Motion in a straight line is called linear motion and straight line motion which repeats over and over is known as reciprocating motion. Types of Motion

• The system diagram for a rack and pinion mechanism is shown below. This mechanism converts rotary motion to linear reciprocating motion.

This example of a control is shown as a simulation model in the slide 10. Activity Extensions. 1. A number of other modelling challenges of control systems, based on the Biogas

Generator , can be found in the extension materials. Slides 24-27.2. Study the mechanisms in a bicycle and explain how motion is converted.

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Electronic simulation software ,such as YENKA as shown here, allows mechanisms and electrical circuits to be combined and the resulting system simulated.

Activity: Shed Gate control.

1.Draw up a sub-system diagram for the system shown for opening and closing the shed gate.

2.Build the circuit shown using suitable electronic simulation circuit software.

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The video clip shows how grain, and other materials can be used to produce biogas. ActivityHow many examples of rotary motion converted to linear motion, or vice versa, are shown in the video clip? Activity Extension. A number of other modelling challenges can be found in the extension materials. Slides 25-27.

How it Works - Biogas Plant

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ActivityWatch each of the

following three videos.

1. Micro-hydro power2. Wave Power3. Combined heat and

power plant

Choose one to discuss in more detail and then draw up a sub-system diagram showing the energy transformations in the process.

How it Works - Micro-hydro Process

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How it Works - Wave Power ProcessActivity

Choose one video/audio clip to discuss in more detail and then draw up a sub-system diagram showing the energy transformations in the process.

For background to energy generation from the ocean please click.

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Activity

Choose one video/audio clip to discuss in more detail and then draw up a sub-system diagram showing the energy transformations in the process.

Extension Activity. Find out how a steam turbine works and compare its complexity to a wind turbine or tidal power turbine.

How it Works - Heat and Power Process

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Presentation

Prepare a presentation which demonstrates your understanding of the importance of engineers to society.

The presentation should last around 5 minutes.

The presentation could be based on a historical contribution made by engineering, a current product or project, or a future development.

• A historical contribution could be a description of an invention or inventor, or a civil engineering project from the pyramids to castles, roads, bridges and so on.

• A current contribution should focus on the role of one particular engineer in the development of an important product or project.

• A future contribution should look at how an emerging technology could be developed to provide benefits to individuals or society as a whole.

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Engineering Contexts and Challenges

Extension work based on the Biogas Generator

The social and environmental impact of engineering slide 17

Engineering Sub Branchesslides 18-23

Systems Modelling slides 24-27

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The social and environmental impact of engineering.ActivityThere are many benefits for the distillery company from the biomass project. List four of these benefits and explain them.

This project would help to reduce the need for energy generated from finite (fossil fuel) sources. What benefits would a power generation plant of this type have for society as a whole?

The project would also have some advantages and disadvantages to the local community, especially those living close to the plant.•What social and economic benefits would the project bring to the local community?•What disadvantages would there be for those living around the plant, both during the building phase and afterwards?•In terms of the health and wellbeing of society - discuss the pros and cons of supporting a company that produces alcohol?

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Engineering Sub- branches

•Mechanical Engineering slide 19

•Civil Engineering slide 20

•Electrical Engineering slide 21

•Chemical Engineering slide 22

•Hybrid Engineering slide 23

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Activity: Which of these sub branches could be involved in the Biomass Project and what would be their role?

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Activity: Which of these sub branches could be involved in the Biomass Project and what would be their role?

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Activity: Which of these sub branches could be involved in the Biomass Project and what would be their role?

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Activity: Which of these sub branches could be involved in the Biomass Project and what would be their role?

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There are many others, including industrial engineering, nuclear engineering, agricultural engineering and applied engineering.

Activity: Which of these sub branches could be involved in the Biomass Project and what would be their role?

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Systems Modelling

The following ‘modelled’ examples are based on the systems, controls and mechanisms found in the Biomass generator and similar engineering systems.

• Grain filling warning system. Slide 25• Grain hopper sensing system. Slide 26• Temperature sensing system. Slide 27

Activity. Using appropriate modelling systems and or boards: design, assemble, test and evaluate your solutions.

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Challenge: Grain filling warning system.1.Design a system which will light a red LED while the substrate tank is filling. Once a float switch detects that the tank is full a solenoid should close the filler pipe and the red LED should go off. 2.Draw a system diagram3.Draw a sub-system diagram4.Build and test the simulated circuit shown.

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Challenge: Grain hopper sensing system.1.Design a system that will spin a mixing paddle once a light sensor detects it is dark (showing that the grain tank is full) or when a test switch is pressed.2.Draw a system diagram3.Draw a sub-system diagram4.Build and test the simulated circuit shown.5.Suggest other uses for this type of system.

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Challenge. Temperature sensing system.1.Design a system that will switch on a heater (simulated by a lamp) when the temperature in the fermenting tank falls and the heater switch is on.2.Draw a system diagram3.Draw a sub-system diagram4.Build and test the simulated circuit shown.5.Comment on the success of the design and suggest other uses for this type of system.