WSRESTF - Foundation Studies
Section outline
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Foundation Studies
This Foundation Studies package will provide you with the basic knowledge required to undertake CREST's MSc in Renewable Energy Systems Technology. For many of you, much of the course will comprise of revision. Please read the information below carefully before you begin
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Why is an understanding of engineering maths necessary?
The CREST MSc is not a heavily mathematical programme, but some elements do require mathematical treatment. Read more in the 'Maths Introduction' document below..
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After completing this topic, you should understand:
- The mathematical concepts that underpin the more technical modules of the MSc.
- Various mathematical equations in the context of the practical aspects of renewable energy technology.
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You will not have to use Taylor Series yourselves, but it is a common way in which useful approximations are generated (eg that sinq can be approximated by q for small angles). There are occasions when lecturers will use this to provide a simpler formulation (eg expressions relating to extreme winds in the Wind II module).
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These notes are here simply to remind you what complex numbers are since they are used in AC analysis.
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Differential equations arise in thermal analysis (as in Solar I) and to describe water waves (as in the Water Power module). You will not be expected to solve differential equations as part of the course but it is important that you understand where the presented solutions come from, and the role of boundary conditions. Laplace Transforms are not explicitly used in the MSc but they do underpin basic control analysis.
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This brief note is simply to introduce the concept of state space analysis so that you will recognise the terminology. You will not be expected to apply this approach yourselves.
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These notes are simply to assist you in understanding what a spectral density function is. You will not be expected to manipulate such functions, but they are a handy way to represent wind speed variation (as in Wind I and Wind II modules).
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Wind turbines are examined as dynamic systems in Wind II and these notes provide the basis of dynamic analysis. You will not however be expected to manipulate matrices as part of the course.
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Basic applied probability and statistics are used to describe stochastic processes like wind speed. You will be expected as part of Wind I and Wind II to undertake straightforward probability calculations. The concept of autocorrelation is used in Wind II to describe the time structure of wind fluctuations.
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1. Why do I need maths?
2. Taylor series
3. Complex numbers
4. Differential equations and Laplace transform
5. State space analysis
6. Fourier transform and spectral density functions
7. Matrices and Eigen value analysis
8. Statistics and applied probability
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Why is an understanding of electricity necessary?
The CREST MSc concentrates mainly on those technologies that harness the Earth's natural energy flows and convert them to electrical energy. Therefore, an understanding of the ways in which electrical energy is generated and transported (whether in AC or DC applications) is fundamental to many aspects of these technologies.
Study tips
This section consists of six units (FE1 DC Circuits to FE6 Semiconductors) each with a series of compact study notes and some with self-test questions. In each section, work through the study notes sequentially. Make sure that you understand any worked examples. Where available, you may wish to tackle the self-test questions as they occur in the sequence. If you encounter difficulties, return to the study notes and focus on the relevant topics before re-visiting the self-test.
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Introduction
Prior to commencing the foundation studies course, you should already have an understanding of the basic concepts of electricity, such as Ohm's law, series and parallel circuits and conductance. The following section is therefore intended only as a review of your existing knowledge.
Why is an understanding of DC Circuits necessary?
Electricity is generated transmitted, distributed and consumed mainly in AC form. This course mainly deals with those renewable energy technologies that are used to generate electricity; hence it is vital that a treatment of renewable energy technology deals with the integration of such sources into existing electrical networks.
DC circuit theory provides the necessary foundations for the treatment of AC circuits. It is also required in the analysis of photovoltaic systems and the understanding of power electronic converters used to interface some renewable energy-sourced generators to electrical networks.
AC circuit theory provides the information needed to understand the basic principles of:
the operation of electrical generators used to convert renewable energy into electricity.
the transfer of electrical energy from the point of generation to the point of use.
the effects of integrating dispersed renewable energy-sourced generation into a pre-existing power network fed mainly from conventional generators.
The material in the whole of this unit is required as background for all the other Foundation Units on electricity (FE-2 to FE-5).
At the beginning of each section the course module(s) that requires the material in this particular section as background knowledge are indicated in bold italics.
Study tips
This unit contains an itemised summary of the pre-requisite knowledge required prior to commencing the Foundation Studies course and self-test questions. You should be familiar with this materials from your high school Physics or university Science/Engineering degree courses. The material is very basic and it represents essential background knowledge for the study of AC circuits. You are recommended to study the unit in the following sequence:
From the "Syllabus" page, work through the list carefully making sure you are familiar with all the itemised elementary concepts. If any of these concepts are new to you (or perhaps you were once familiar with them but your memory requires refreshing), a link at the end of each section will take you to in-depth Foundation Backup (FB) material on each subject. It is hoped that very few students will need to follow this procedure!
Tackle the self-test questions as they occur in the sequence, if you decide to test your knowledge of this topic. If you encounter difficulties, return to the study notes and focus on the relevant topics before re-visiting the self-test.
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Why is an understanding of DC Network Analysis necessary?
Renewable energy sources are used mainly to generate electrical power, which is injected into power networks consisting of a large number of transmission lines, other conventional generators and consumers. Such power networks, especially in developed countries, are of considerable complexity. To determine the way these injected powers flow from generators to consumers requires complex calculations based on network analysis. This unit provides background material for the development of AC circuit theory and of the mathematical expressions that define the power flows in a network.
The material in the whole of this unit is required as background knowledge for all the other Foundation Units on electricity (FE-3 to FE-5)
At the beginning of each section the course module(s) that requires the material in this particular section as background knowledge are indicated in bold italics.
Objectives
After completing this topic, you should understand:
- The basic ideas of DC network analysis.
- Thevenin's Theorem, a technique of considerable use in power systems engineering.
Syllabus
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Why is an understanding of AC Theory necessary?
Renewable energy sources are used mainly to generate AC electrical power, which is injected into power networks consisting of large number of transmission lines, other conventional generators and consumers. Such power networks, especially in developed countries, are of considerable complexity. To determine the way these injected powers flow from generators to consumers requires complex calculations based on network analysis. This unit introduces the basic AC circuit theory that enables students to carry out network analysis in simple power circuits consisting of R, L and C components. This knowledge is an essential prerequisite in the understanding of power flows in networks. Frequently, renewable energy generators are interfaced to power networks through power electronic converters. The non-linear nature of such converters is examined and the reasons why converters generate harmonics are explained. The undesirable effects of harmonics injected into power networks are discussed.
All sections of this unit are required as background material for Unit FE-4. Some sections contain simple exercises.
At the beginning of each section the course module(s) that requires the material in this particular section as background knowledge are indicated in bold italics.
Note: The text uses 60Hz rather than 50Hz as the mains frequency. This is of no consequence in the understanding of the material and in its application to 50Hz systems.
Objectives
After completing this topic, you should understand:
- The reason why alternating current is invariably used for the generation of electricity.
- Complex numbers for the easy manipulation of A.C. quantities in circuit analysis.
- The concepts of inductive and capacitive reactance and the analysis of A.C. circuits containing resistors, capacitors and inductors.
- What happens in circuits when the signals are non-sinusoidal and the function of filters in suppressing unwanted harmonics.
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Why is an understanding of Power in AC Circuits necessary?
Renewable energy sources are used mainly to generate AC electrical power, which is injected into power networks consisting of a large number of transmission lines, other conventional generators and consumers. Such power networks, especially in developed countries, are of considerable complexity. To determine the way these injected powers flow from generators to consumers requires complex calculations based on network analysis. This unit introduces the basic concepts of active, reactive and apparent power. These are the basic tools needed to understand and calculate flows of energy from generators to consumers. In all AC power systems (excluding very low capacity ones) power is generated and transported in three-phase form. The reasons why this is so and the tools to deal with power flows in such systems are outlined. All this knowledge is an essential prerequisite for the understanding of power flows from renewable generators into networks.
All sections of this unit are required as background material for Unit FE-5.
At the beginning of each section the course module(s) that requires the material in this particular section as background knowledge are indicated in bold italics.M/p>
Note: The text uses 60Hz rather than 50Hz as the mains frequency. This is of no consequence in the understanding of the material and in its application to 50Hz systems.
Objectives
After completing this topic, you should understand:
- Electrical power aspects in networks consisting of resistive and reactive components.
- How the changing power with respect to time associated with a resistor implies the irreversible conversion of electrical energy to heat.
- Why the changing power with respect to time associated with reactive components is oscillatory in nature.
- The concepts of active, reactive and apparent power as well as power factor.
- The practical implications of low power factor and the practice of power factor correction.
- How reactive and active power can be easily calculated using the complex notation of voltage and current.
- Single and three-phase systems in terms of generation, transportation and utilisation of energy.
- Power in Resistive and Reactive AC circuits.
- Active, Reactive and Apparent Power.
- The Significance of Power Factor.
- Power Factor Correction.
- Complex power.
- Single Phase Power Systems.
- Three Phase Power Systems.
- Three Phase "Y" and "D" Configurations.
- Power in three-phase systems.
- Generation of three-phase voltages.
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Why is an understanding of Electrical Machines necessary?
Renewable energy sources are used mainly to generate AC electrical power, which is injected into power networks consisting of large number of transmission lines, transformers and other conventional generators and consumers. Such power networks, especially in developed countries, are of considerable complexity. To determine the way these injected powers flow from generators to consumers requires complex calculations based on network analysis. This unit introduces the basic concepts of the electrical machines that are found in power networks. Transformers are used in all but the most primitive networks to step-up or -down transmission network voltages for efficient operation. The knowledge of the transformer equivalent circuit is essential to perform power system analysis studies. There are two types of generators (synchronous and asynchronous) for the conversion of mechanical into electrical energy. Knowledge of the basic operating principles of these generators is essential to appreciate their advantages and limitations when used in renewable energy conversion systems.
All sections of this unit are required as background material for Unit FE-6.
At the beginning of each section the course module(s) that requires the material in this particular section as background knowledge are indicated in bold italics.M/p>
Note: The text uses 60Hz rather than 50Hz as the mains frequency. This is of no consequence in the understanding of the material and in its application to 50Hz systems.
Objectives
After completing this topic, you should understand:
- The operating principles, equivalent circuit and constructional details of transformers.
- The production and properties of a Rotating Magnetic Field (RMF).
- Operational characteristics and limitations of a synchronous generator.
- How, in induction machines, rotor currents are generated through induction by virtue of the slip between the stator RMF and the rotor speed.
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What is this unit about?
This unit provides some basic qualitative grounding on the physics underpinning the development of semiconductor devices. The atomic structure of matter is discussed with reference to (i) the distinct energy levels at which electrons may exist in isolated atoms and (ii) the energy bands in solids. The differences between a conductor, an insulator and a semiconductor are then explained in terms of conduction, forbidden and valence bands. The electron and hole flow theory in semiconductors is then discussed as well as how the properties of the semiconductor are affected by doping. The characteristics of N-type and P-type semiconductors are explained and how a PN junction is realised in practice. The investigation of current flow in PN junctions with forward and reverse bias leads to the concept of the semiconductor diode and its construction and operation. Finally the principle of transistor operation is briefly outlined and how this has spawned solid state switching devices suitable for power electronic applications.
Why is an understanding of Semi-conductors necessary?
The direct generation of electricity from sunlight is a major part of the Solar Power I and II modules. This energy conversion is achieved through photovoltaic devices, which are based on semiconductor technology. This unit provides the basic qualitative background material necessary to understand the analytical treatment of photovoltaics in Solar Power I. Renewable energy generators are often interfaced to the electricity power networks through energy conditioning interfaces. Such interfaces use power electronic switching devices to implement the conditioning. The qualitative knowledge of how solid switching devices operate is an essential prerequisite for the understanding of the mode of operation of interfaces and the influence such interfaces have on the RE generators and power networks to which they are connected.
Objectives
After completing this topic, you should understand:
- Some basic facts on atomic structure and semiconductors.
- The differences between a conductor, an insulator and a semiconductor, in terms of forbidden and valence bands.
- The electron hole flow theory in semiconductors.
- The semiconductor diode and its characteristics.
- The transistor and its characteristics.
Contents
1. Semiconductor Theory
- 1.1 Atomic Structure.
- 1.2 Energy Bands.
- 1.3 Covalent Bonding.
- 1.4 Conduction Process.
- 1.5 Doping Process.
- 1.6 N-Type Semiconductor.
- 1.7 P-Type Semiconductor.
2. The PN Junction
- 2.1 Construction.
- 2.2 Current Flow in the N-Type Material.
- 2.3 Current Flow in the P-Type Material.
3. The Junction Barrier
- 3.1 Forward Bias.
- 3.2 Reverse Bias.
- 3.3 The Diode.
4. Solid State Switching Devices
Self-Test
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Why is an understanding of biomass necessary?
All Earth's bioenergy originates from the sun. Only a small proportion of the Sun's energy incident on the Earth's surface is fixed by organic matter and stored.
This energy is recycled through a series of natural and chemical conversions. At some stage in the cycle we can intervene and use the bio-energy when it is optimally suited to act as a source of chemical energy and hence as a fuel
It is essential to understand the basics of cell biology, cell chemistry and cell metabolism in order to gain a deeper insight into the energy that is stored in biofuels. It is for this reason that the fundamentals of biochemistry are covered in the first parts of this unit. The last section covers the process of photosynthesis. This is the process whereby plants convert solar energy to chemical energy, which is stored as a carbohydrate, cellulose.
Study tips
This unit consists of a series of compact study notes and self-test questions. You are recommended to study the unit in the following sequence:
- Tackle the pre-test questions, where available, to gauge your prior knowledge. This will indicate whether you need to concentrate on a particular unit.
- From the "Syllabus" page, work through the study notes sequentially. Make sure that you understand any worked examples.
- Where available, you may wish to tackle the self-test questions as they occur in the sequence. If you encounter difficulties, return to the study notes and focus on the relevant topics before re-visiting the self-test.
Objectives
After completing this topic, you should understand:
- After completing this topic, you should understand the basic structure of a cell and the differences between prokaryotic and eukaryotic cells.
- Describe the processes of metabolism at the cellular level
- Outline the bioenergetics of cellular metabolism
- Describe the biochemical pathways relevant to catabolism
- Explain in detail the biochemical processes involved in photosynthesis
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Why is an understanding of fluid mechanics necessary?
Wind and water turbines convert energy in a fluid (namely moving masses of air or water) into mechanical energy. To understand and analyse the behaviour of such turbines it is necessary to have a grasp of basic fluid mechanics.
The operation of wind turbines is based on the lift and drag produced by airfoils. To understand the behaviour of wind turbines it is essential to understand the concepts of laminar and turbulent flow.
Study tips
This unit consists of a series of compact study notes and self-test questions. You are recommended to study the unit in the following sequence:
- Tackle the pre-test questions, where available, to gauge your prior knowledge. This will indicate whether you need to concentrate on a particular unit.
- From the "Syllabus" page, work through the study notes sequentially. Make sure that you understand any worked examples.
- Where available, you may wish to tackle the self-test questions as they occur in the sequence. If you encounter difficulties, return to the study notes and focus on the relevant topics before re-visiting the self-test.
Objectives
After completing this topic, you should understand:
- The basic aspects of the nature and properties of fluids.
- Hydrostatic forces on surfaces.
- Fluid dynamics: the Continuity, Bernoulli and Momentum equations.
- Laminar and turbulent flow and boundary layers.
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- Define the nature of fluid.
- Show where fluid mechanics concepts are common with those of solid mechanics and indicate some fundamental areas of difference.
- Introduce viscosity.
- Define the appropriate physical properties and show how these allow differentiation between solids and fluids as well as between liquids and gases.
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- Introduce the concept of pressure; Prove it has a unique value at any particular elevation;
- Show how it varies with depth according to the hydrostatic equation and
- Show how pressure can be expressed in terms of head of fluid.
This understanding of pressure will then be used to demonstrate methods of pressure measurement that will be useful later with fluid in motion and also to analyse the forces on submerges surface/structures.
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At the end of this section you should understand the concepts of:
- Introduce concepts necessary to analyse fluids in motion.
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Introducing Reynolds number and the concepts of laminar and turbulent flow
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Why is an understanding of heat transfer necessary?
The operation of active or passive heating systems (such as solar hot water or passive solar bui) are based on the principles of heat transfer. Heat pumps are commonly used in modern heating and cooling systems and their design is based upon the principles of thermodynamics. Therefore, an understanding of these processes is important.
Study tips
This unit consists of a series of compact study notes and self-test questions. You are recommended to study the unit in the following sequence:
- Tackle the pre-test questions, where available, to gauge your prior knowledge. This will indicate whether you need to concentrate on a particular unit.
- From the "Syllabus" page, work through the study notes sequentially. Make sure that you understand any worked examples.
- Where available, you may wish to tackle the self-test questions as they occur in the sequence. If you encounter difficulties, return to the study notes and focus on the relevant topics before re-visiting the self-test.
Objectives
After completing this topic, you should understand:
- The concepts of mass transport, conduction, convection and radiation.
- How the heat transfer coefficient relates to practical heat transfer problems.
- Energy conservation and the first and second laws of thermodynamics.
- The Carnot cycle and entropy in the context of heat transfer.
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Why is an understanding of mechanics necessary?
- Many renewable energy conversion devices (such as wind turbines) are a complex arrangement of moving masses. In order to understand and analyse their behaviour, it is necessary to use the principles of mechanics.
- Renewable Energy devices convert one type of energy into another type (usually electricity). It is therefore essential to have a good understanding of work, power, energy and conversion efficiency.
Study tips
This unit consists of a series of compact study notes and self-test questions. You are recommended to study the unit in the following sequence:
- Tackle the pre-test questions, where available, to gauge your prior knowledge. This will indicate whether you need to concentrate on a particular unit.
- From the "Syllabus" page, work through the study notes sequentially. Make sure that you understand any worked examples.
- Where available, you may wish to tackle the self-test questions as they occur in the sequence. If you encounter difficulties, return to the study notes and focus on the relevant topics before re-visiting the self-test.
Objectives
After completing this topic, you should understand:
- The concepts of mass, force, velocity and acceleration and the use of vectors.
- The behaviour of bodies in linear and angular motion.
- The important concepts of work, power and energy.
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At the end of this section you should understand the concepts of velocity, speed and acceleration. You should also be able to solve problems involving:
- Linear motion.
- Angular motion.
- Circular motion.
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At the end of this section you should understand the relationship between mass, force and acceleration. And be able to solve problems using:
- Newton's 1st law of motion.
- Newton's 2nd law of motion (in terms of F = ma)
- Newton's 3rd law of motion.
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At the end of this section you should understand the concepts of:
- Work, energy and power.
- Conservation of Energy.
- Moment, couple and torque.
and sucessfully complete calculations using these concepts.
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