Energy Unit if 3 ESO Technology

Unit 5. Energy 5.1 Energy 1.1Units 1.2 Forms and Sources 5.2 Electric energy 2.1 Production 2.2 Distribution 5.3 Main Power Stations 5.4 Alternative Power Stations 5.5 Consume

5.1.1 Energy. Units Energy is the capacity of an object to do a work. And work is the force applied along a distance

5.1.1 Energy. Units In physics we define mechanical work as the amount of energy transferred by a force acting through a distance W= F • d d= distance between A and B F= Force applied to move the object F d

5.1.1 Energy. Units Therefore, in this example, the energy that black cartoon has, the express the work that can apply to this box,

5.1.1 Energy. Units Units There are several units of energy that are used in special areas, the most popular are the j, cal and kwh. Joule calorie kwh

5.1.2 Forms and Sources Joule (J) is the International System’s unit for work, and is usually expressed in Kj. 1kj is the energy need to raise 100kg 1 meter high 1 meter

5.1.2 Forms and Sources Calorie (cal) This unit is usually used to express energy that involves calorific transference. When energy is used in the alimentary industry, it’s usually express in Kcal. In the USA, they write Cal instead of Kcal… In order to heat 1 L of water from 20 to 21 ºC we need 1kcal

5.1.1 Energy. Units A human being needs around 2000 kcal per day of energy to do all the work that it needs.

5.1.1 Energy. Units When you drink a Coke you are absorbing 139 Kcal of energy that is stored in the 39gr of sugar dissolved in the liquid.

5.1.1 Energy. Units 1º Exercise: Investigate the energy that these foods have per 100 gr: Yogurt Big Mac Bread Apple Biscuits Orange Fanta Cereals Oil Chips Butter

5.1.1 Energy. Units KiloWatt/hour(kwh) It’s the unit used to measure the electric consumption of an electric installation. When we use a hairdrier of 1000 W for 1h, we have consumed 1 kwh

5.1.1 Energy. Units Conversion units 1Kwh= 1000Wh 1 W= 1 j/s 1calorie= 4,18 joules 2º Exercise: Calculate the energy of a Coke in joules. Calculate the energy measured in kwh that we absorb in 2h when we drink 2 Cokes?

5.1.2 Forms and Sources So Energy is the capacity of an object to do a work, and it can be stored in different forms of enery: Calorific energy Light energy Mechanical energy Electrical energy Electric energy Chemical energy Nuclear energy

5.1.2 Forms and Sources The law of conservation of energy expresses that can neither be created nor destroyed, it can only be transformed from one state to another Calorific energy Light energy Mechanical energy Electrical energy Electric energy Chemical energy Nuclear energy

5.1.2 Forms and Sources In order to obtain energy we have to use the different energy sources present in Earth: oil, coal, wind, uranium, etc.

5.1.2 Forms and Sources We can classify the energy sources according to its: Origin: Renewable or Non Renewable Historical use : traditional or alternative Transformation: Primary or secondary

5.1.2 Forms and Sources 3º Exercise: Explain the difference between the concepts of source and form of energy. Define the six groups of energy sources, and give four examples of each.

5.1.2 Forms and Sources Origin: Renewable : These sources are Inexhaustible, therefore we can use them continuously. For example: Wind, Waves, etc…

5.1.2 Forms and Sources Origin: . Non Renewable : These sources are exhaustible, therefore we consume the source when we use it. For example: oil, Uranium

5.1.2 Forms and Sources Historical use : Traditional : these sources have been used for at least 30 years, and they provide more than the 90% global energy. They are: Hydraulic, Coal, Oil, Gas, Uranium

5.1.2 Forms and Sources Historical use : Traditional Alternative : these sources can provide energy but they can’t displace the alternative energy because they are cheaper or easier to obtain. For example Solar Wind bio-mass Wave Geothermal

5.1.2 Forms and Sources Transformation: Primary: These sources are obtained directly from the environment and they can be used directly without any transformation. For example: Hydraulic, Coal, Oil, Gas, Solar Wind bio-mass Wave Geothermal

5.1.2 Forms and Sources Transformation: Primary : Secondary: These sources are obtained after the transformation of a primary source. We use them because they are cleaner or easier to use For example: Electricity, Oil derivatives (Gasoline, Diesel, etc), Town Gas

5.1.2 Forms and Sources 5º Exercise: Make a list of 20 objects indicating the source of energy used and the energy obtained . For example: TV-Electricity Object Energy Source Energy obtained TV Electricity Light . . . . . . . . .

Electricity production . Why do we like Electricity so much?

5.2.1 Electric energy. Production Electricity is the principal source of energy in the developed homes and in industries because it’s the cleanest and most versatile energy.

5.2.1 Electric energy. Production 6º Exercise: Compare the use of electricity at home with the use of coal, oil, gas, solar, wind, geothermal, uranium. 7º Exercise: What do we mean when we say that the electricity is clean?

As we know, if we want to create an artificial electric current, we only need: A closed circuit An artificial magnetic field A mechanical energy to move the circuit inside the field. 5.2.1 Electric energy. Production

When we have all elements together, we find that we create an alternate electric current due to the movement of the spiral. 5.2.1 Electric energy. Production

Therefore once we have the circuit and the magnetic field (generator) we only need an energy source to move the turbine attached to the circuit inside the generator. 5.2.1 Electric energy. Production Generator turbine

In a Power Station the turbine is moved directly by the source or using steam. 5.2.1 Electric energy. Production turbine steam

In a Power Station the turbine is moved directly by the source or using steam. 5.2.1 Electric energy. Production They move the turbine with water Wind or waves

In conclusion we will always find these elements in a Power Station: 5.2.1 Electric energy. Production Mechanical Energy Generator Turbine Electric generation Electric Transformation Electric Transport Transformer Primary Energy

And this is the summary of the production in a block diagram 5.2.1 Electric energy. Production Mechanical Energy Electric generation Electric Transformation Primary Energy Electric Transport Water or Air Steam from a combustion, nuclear reaction, solar or geothermal Turbine Generator Transformer

Once we create electricity we have to transport it to the final users. Nowadays we use these elements: 5.2.2 Electric energy. Distribution Transformer Pylons Transformer Final User

Why do we need a transformer??? 5.2.2 Electric energy. Distribution

All conductors have resistance, and its opposition to the intensity creates HEAT !!! 5.2.2 Electric energy. Distribution so our electric distribution could be a huge heater!!!! P=I 2 R

Therefore, in order to transmit high electric power, we have to decrease the intensity by increasing the voltage 5.2.2 Electric energy. Distribution So, with high voltage distribution, we lose less calorific energy and thanks to that we can use thinner cables

Exercise 8 Calculate the % of energy wasted in calorific energy when we transport 1250 kw with a cable that has 10 Ohm if: Voltage is 250kV Voltage is 25 KV 5.2.2 Electric energy. Distribution

But, how does it work? 5.2.2 Electric energy. Distribution

Any transformer is based in the relation between the magnetic field created by two reels that have the same nucleus 5.2.2 Electric energy. Distribution Nucleus Reel Reel

This is the relation between the I and V in each Reel: 5.2.2 Electric energy. Distribution Nucleus Entrance Exit

Therefore, if we want to have a high volt current, we have to increase the number of spirals of the 2º reel (N 2 ) 5.2.2 Electric energy. Distribution

Coal power Station 5.3 Power Stations

Coal power Station Diagram 5.3 Power Stations Steam Mine Furnace Boiler Turbine Generator Transformer Cooler Mechanical Energy Electricity Cool Water Heat Cranes High Volt Steam Coal

9º Exercise. Draw the diagram of all Power Stations as we have seen in the Coal Station Diagram 5.3 Power Stations

Coal power Station Advantages Inexpensive compared to other energy sources Coal is present in most of the countries, so they don’t have to buy it abroad By-product of burning, ash , can be used for concrete and roadways Disadvantages Limited supply, non-renewable resource. 100 years The Carbon dioxide generated increase the effect of the global warming. Generated smoke can cause health conditions such as emphysema Sulphur dioxide and nitrogen emissions can bind to water creating acid rain Coal mining mars the landscape 5.3 Power Stations

Nuclear power station 5.3 Power Stations

Nuclear power station Advantages Worldwide nuclear energy avoids on average the emission of more than two billion metric tones of carbon dioxide per year, decreasing the effect of the global warming. Although nuclear power reactors are expensive to build, they are relatively cheap to operate. It is possible to generate a high amount of electrical energy in one single plant. Disadvantages The waste from nuclear energy is extremely dangerous and it has to be carefully looked after for several thousand years . Despite a generally high security standard, accidents can still happen. Nuclear power plants as well as nuclear waste could be preferred targets for terrorist attacks. Is a non renewable source. 50 years 5.3 Power Stations

Hydro Power Station 5.3 Power Stations

5.3 Power Stations Hydro Power Station Advantages When the electricity is generated, no greenhouse gases are made. Water is a renewable energy source and free. We create huge potable water deposits. Disadvantages The dam is expensive to build and the nearby area has to be flooded In drought season we may not have enough water to turn the turbines.

Solar Power Tower Plant 5.3 Power Stations

solar photovoltaic Plant 5.3 Power Stations

Solar Energy Advantages Inexhaustible fuel source No greenhouse gasses emited Versatile since it is used for powering items as diverse as solar cars and satellites Disadvantages It does not work at night. Very diffuse source means low energy production. Only areas of the world with lots of sunlight are suitable for solar power generation They need great lands creating high temperatures below the panels 5.3 Power Stations

Wind Plant 5.3 Power Stations

Wind Plant Advantages It is available over a greater area than occurs with fossil fuels. There is no air pollution after manufacture. Modern wind energy converter systems can be set up for individual houses. Wind energy produces more energy per area of land than other energy sources. Disadvantages Modern wind energy systems are expensive, although the source is free. They can be rather ugly or the noise of the rotor could be annoying if the installation is located close to homes or workplaces. The wind does not blow all the time. Potential TV interference caused by rotor. 5.3 Power Stations

5.3 Power Stations Tide Energy

5.3 Power Stations Tide Energy Advantages Tides are free once the power station has been built and will not run out. No greenhouse gases are produce. We know exactly when the tides happen so we know when electricity will be made. Disdvantages Dams may not be good for plants and animals that live nearby. The tides only happen twice a day, so can only produce electricity for that time.

5.3 Power Stations Wave Energy

5.3 Power Stations Wave Energy Advantages Waves are free and will not run out so the cost is in building the power station. Wave power does not produce greenhouse gases. There are very few safety risks with wave power generation. Disdvantages Waves can be big or small so you may not always be able to generate electricity. You need to find a way of transporting the electricity from the sea onto the land. Not many people have tried to generate electricity this way yet so the equipment is expensive.

5.3 Power Stations Biomass . Natural biomass Dry Biomass Waste from industrial process Wet Biomass Human or animal disposal Energetic Crops High Energy Plants Are cultivated

5.3 Power Stations Biomass Advantages The fuel is cheap and can use things that we might otherwise throw away. We can find waste everywhere and should not run out. Disadvantages When the fuel is burned greenhouse gases are made which pollute the environment. Sometimes people grow biomass crops where we could grow food. We may not have enough space to grow enough biomass fuel.

5.3 Power Stations Geothermal Energy

5.3 Power Stations Geothermal Energy Advantages Geothermal energy does not produce greenhouse gases The energy source is free and will not run out Disadvantages There are not many places where we can build geothermal power stations Harmful gases and minerals may occasionally come up from the ground below. These can be difficult to control.

5.3 Power Stations Fusion Energy the Future Energy

5.1.3 Consume In Spain, we use too much fossil energy to produce electricity

5.1.3 Consume In Spain, we use too much fossil energy to produce electricity Fuente de energía Producción 2007 (ktep) 2007 % Producción 2008 (ktep) 2008 % 2008/2007 Carbón 5.865 19,3 4.374 14,2 -25,4 Petróleo 143 0,5 127 0,4 -11,2 Gas natural 16 0,1 14 0,0 -10,9 Nuclear 14.360 47,3 15.368 50,0 7,0 Hidráulica 2.342 7,7 2.001 6,5 -14,5 Otras energías renovables 7.624 25,1 8.841 28,8 16,0 Total 30.348 100,0 30.725 100,0 1,2 Año Grado de autoabastecimiento energético 1975 22,6 1985 38,9 1995 28,0 1998 25,6 2003 22,1 2008 21,6 Fuentes: 1975-1998:, [6] 2003: [7] 2008: Ministerio de Industria, Turismo y Comercio [1

5.1.3 Consume In Spain, we use too much fossil energy to produce electricity Tipo de central GWh Total Principales Centrales de Producción Carbón 49.647 As Pontes 7.901 GWh Compostilla II 6.454 GWh Litoral de Almería 5.739 GWh Aboño 5.580 GWh Teruel 4.842 GWh Ciclo combinado 95.529 Bahía de Bizkaia 4.632 GWh Cartagena 6 4.126 GWh Castelnou 3.688 GWh As Pontes 3.669 GWh Bizkaia Energia 3.669 GWh Nuclear 58.973 Almaraz II 8.607 GWh Trillo I 8.284 GWh Cofrentes 8.156 GWh Ascó I 7.694 GWh Almaraz I 7.491 GWh Hidroeléctrica 21.428 Cuenca Norte 7.042 GWh Cuenca Ebro-Pirineo 5.847 GWh Cuenca Duero 4.941 GWh Cuenca Tajo-Jucar-Segura 2.870 GWh Cuenca Guadalquivir-Sur 612 GWh Eólica 31.777 Fuel - Gas 10.691 Mini-hidráulicas 4.417 Otras renovables 7.645 Otras no renovables 23.314 Fuente: Red Eléctrica de España (Informe 2008). Elaboración propia wikipedia

4. Thermal machines The thermal machines transform the thermal energy from combustion into mechanical energy. We classify these machines according where the combustion takes place: Internal combustion : the fuel is burned outside the engine. For example the steam engine. External combustion : the fuel is burned inside the engine creating a explosion . For example a car engine

A steam engine transform heats water using fuel combustion in order to obtain high preassure steam that is used to move a mechanism. 4.I Thermal machines. External combustion Steam engine Watt used this engine to move trains, ships and the first industrial machines that created the first Industrial Revolution.

4.I Thermal machines. External combustion Steam engine Simple machine

4.Ib Internal explosion The four times engine it’s the most popular engine due to it’s economy and resistance. It needs only air, oil and an ignition source from an electric discharge. 4.ii Thermal machines. Internal combustion 1 Admision 2 Compression 3 Explosion 4 Escape

1.Admision : The admission valve is opened and at the same time the piston goes down creating vacuum absorbing air and fuel

2.Compression : Both valvules are closed and the pistón goes up compresing the mixture of air and fuel. This movement is created by an electric engine of the starting mechanism. After the first complete process the inertia energy reboot the process over again.

3.Explosión- Expansion : An electric discharge from the spark plug explode the mixture creating high pressure gases that makes the piston goes down spark plug

4. Escape : The escape calve is opened and the combustion gases are expulsed by the piston that goes up again. We have reached the start position again

Admision Valve Escape Valve Piston movement Admision OK Compression Explosion- expansion Escape OK

Two times engine. It is a explosion engine that does the four steps in only two phases. It creates less energy that the four times but is simpler and cheaper.

The diesel engines use gasoil instead of gasoline . The mixture explodes when is compressed thus it doesn’t need a spark plug

Reaction engines 7.1.- Principio de acción reacción This engines works thanks to this principle of the action-reaction when a explosion takes place in a reactor creates a force against the engine and it gives a equal and opposite force.

7.2.- Rocket It carries two deposits with oxigen and fuel that when they are mixtured explode creating a high preassure gases that push up the rocket.

Turborreactor: the air is absorbed and compresed into the combustion chamber and mixtured with querosene. The high preasure gases flow creating a push force and moving the turbina conected to the initial compressor.

Turbofan : used by most of the comercial planes because it generate les noise. The plane moves due to the gases and the helix movement. Turbopropulsor

Energy Unit if 3 ESO Technology

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