Gestão de Energia: 2013/2014 Introduction & Review of Thermodynamics Class # 1 Prof. Tânia Sousa [email protected] Docentes • Tânia Sousa – [email protected] • Carla Silva – [email protected] • Carlos Silva – [email protected] • André Pina – [email protected] Avaliação • Exame (50%) com nota mínima 9.5 val. • Avaliação Contínua (50%) – Trabalhos feitos por grupos de 2/3 alunos – Os trabalhos começam nas aulas e são para terminar em casa – A avaliação é feita nas aulas e com os trabalhos • Trazer um portátil por grupo para as aulas práticas Objectivo 1. Compreender e modelar os fluxos energéticos à escala do país, em sistemas industriais, em edifícios ou equipamentos complexos. 2. Definir acções que permitam racionalizar o uso da energia, quantificando os benefícios económicos e ambientais destas acções. Gestão de Energia: Conteúdo Semana Teóricas 21-02-2014 Apresentação. Revisões Termodinâmica 4ª feira à tarde Práticas 28-02-2014 Balanço Energético Português Energia Primária Final e e Útil. Diagramas de Sankey 07-03-2014 Transições Energéticas. Análise da Eficiência de Sistemas Energéticos Modelos analíticos para a análise energética de sistemas: 14-03-2014 diagramas de blocos Eficiência Energética na Indústria. Regulamento da 21-03-2014 eficiência energética na indústria (SGCIE). Eficiência Energética nos edifícios. 28-03-2014 Regulamentos de eficiência energética nos edifícios. 04-04-2014 Modelos Input-Output Energia e Economia 11-04-2014 Métodos de contabilização da electricidade primária. 18-04-2014 FÉRIAS 25-04-2014 FERIADO Exercícios 02-05-2014 Análise Ciclo de Vida Eficiência energética nos Transportes. Regulamento da 09-05-2014 eficiência energética nos Transportes Exercícios 14-05-2014 Auditorias Energéticas Trabalho V (Tranportes) 4ª feira manhã e à tarde Trabalho I (B.E.N) Trabalho II (Sankey) Exercícios Trabalho III Exercícios Trabalho IV (Input-Output) FÉRIAS FERIADO Exercícios 23-05-2014 Modelação Oferta e Procura de Energia Visita a um Laboratório Tagus Park 30-05-2014 Revisões. Exercícios Course Contents Thermodynamics • Energy and Entropy Balances for Closed & Open Systems • Thermodynamic Cycles: power cycle, heat pump & refrigerator cycle • 1st Pratical Class (exercises) • Bibliography – “Fundamental of Engineering Thermodynamics” Shapiro & Moran Course Contents – T2 • The Portuguese Energetic Balance: – Supply, Conversion & Demand – Energy Carriers BALANÇO ENERGÉTICO tep Total de Carvão Total de Petróleo 2008 IMPORTAÇÕES PRODUÇÃO DOMÉSTICA VARIAÇÃO DE "STOCKS" SAÍDAS CONSUMO DE ENERGIA PRIMÁRIA PARA NOVAS FORMAS DE ENERGIA CONSUMO DO SECTOR ENERGÉTICO 4=1a3 Total de Eectricidade Calor Resíduos Industriais Renováveis Sem Hídrica TOTAL GERAL 23 30 = 24 a 29 36 = 31 a 35 37 38 46 = 39 a 45 47=4+22+23+30+36+37 +38+46 2 327 219 - 223 603 24 949 315 673 3 680 661 5 960 5. 2 525 873 12 612 050 4 157 207 1 953 404 6. 2 444 703 1 079 137 2 597 143 -2 810 996 -1 472 450 475 376 56 103 605 301 270 736 7. 16 608 384 Gases o Outros Derivados 1. 2. 3. 4. CONSUMO COMO MATÉRIA PRIMA DISPONÍVEL PARA CONSUMO FINAL ACERTOS CONSUMO FINAL AGRICULTURA E PESCAS INDÚSTRIAS EXTRACTIVAS INDÚSTRIAS TRANSFORMADORAS CONSTRUÇÃO E OBRAS PÚBLICAS TRANSPORTES SECTOR DOMÉSTICO SERVIÇOS 22= 15 + 21 Gás Natural (*) 4 163 167 923 984 1 142 338 39 800 3 190 679 - 837 17 634 24 022 754 4 372 817 97 193 3 836 162 39 800 3 173 882 24 462 216 1 120 1 367 391 3 206 048 3 1 407 519 112 918 1 275 842 1 275 842 8. 81 170 9 781 695 1 503 961 4 159 099 1 201 714 38 680 1 806 488 18 572 807 9. 10. 10.1 10.2 9 851 71 319 - 47 340 9 829 035 358 801 66 103 - 1 382 1 505 343 3 359 8 444 12 4 159 087 87 218 49 882 1 201 714 2 366 30 844 38 680 279 1 806 209 21 4 - 38 580 18 611 387 451 765 155 277 10.3 71 319 1 085 788 1 027 157 1 340 009 1 154 293 38 680 615 382 5 332 628 10.4 576 210 5 063 50 490 21 631 784 10.5 10.6 10.7 6 680 176 552 680 509 277 6 659 300 190 154 471 46 677 1 157 672 1 427 139 3 452 1 180 750 6 579 6 736 964 3 191 292 2 111 677 14 211 Course Contents – T2 • 2nd Pratical Class & 1st assignment – Each group analyses the PEB for a specific year and compares it with 2012 (bring the computer) • Learning Outcomes: – Be able to retrieve information from the Energetic Balance of a country/region – Compute electricity production efficiencies and other 1st law efficiencies for the country level • Bibliography: – Chap. 2 “Balanço Energético Nacional Metodologia de Elaboração, Evolução da Estrutura e do Consumo Energético Primário”, Ramos, A. – Chap. 2 “Energy Economics”, Bhattacharyya. Course Contents - T3 • From Primary Energy to Energy Services at different scales IAASA - Global Energy Assessment 2012 Course Contents - T3 • World and national patterns of energy use • Energy Transitions Energy Transition Grubler, A. “Energy Transitions” biomass to coal Energy Transition coal to oil Course Contents - T3 • Sankey diagrams for different scales • 1st and 2nd Law Efficiencies Course Contents – T3 • 2nd Pratical Class & 1st assignment – Each group draws the Sankey diagram using e-Sankey for the PEB for a specific year for Portugal • Learning outcomes: – – – – Understand concepts of primary, final & useful energy Historical perspective on world energy use & transitions Use Sankey diagrams to analyse energy systems Understand 1st and 2nd law efficiencies • Bibliography: – Cap. 2 da sebenta “Gestão de Energia”, Águas, M. – Chapter 1 & 16 GEA, IAASA – Cullen and Alwood “The efficient use of energy: Tracing the global flow of energy”, Energy Policy 2010. Course Contents – T4 • Block Diagrams Energy Analysis • 3th Practical Class – Exercises • Learning Outcomes – Compute the energy intensity of a product or service, i.e., the total energy required to produce it – Compute the impact of efficiency measures on the specific energy consumption • Bibliography: – Cap. 5 da sebenta “Gestão de Energia”, Águas, M. Course Contents – T5 • Energy use in industry • SGCIE: Energy efficiency in industry • 4th Practical Class & 3rd assignment – Each group chooses a case study (e.g. the Secil), finds the correct data and describes the production process and computes the specific consumption Course Contents – T5 • Learning Outcomes – Apply & understand the SGCIE legislation • Bibliography: – DL n.º 71/2008; Despachos nº 17449/2008 & 17313/2008 – Chap. 6 “Energy Efficiency and the Demand for Energy Services” Danny Harvey Course Contents – T6 • Energy use in Buildings – Factors controlling energy use in buildings – Techniques to reduce energy use: Course Contents – T6 • RCCTE & RSECE: Energy efficiency in buildings • 5th Practical Class – Exercises • Learning Outcomes – Learn about strategies to reduce energy use in buildings and their impact – Apply & understand the RCCTE & RSECE • Bibliography: – Chap. 4 “Energy Efficiency and the Demand for Energy Services” Danny Harvey – Decreto-lei n.º 118/2013 Course Contents - T7 • IO Analysis at the Macroeconomic scale • Computation of Direct and Indirect Effects of changes in Demand • 6th Pratical Class & 4th assignment – Each group computes energy demand scenarios for a country for 2 & 5 & 10 years based on changes in the economic structure & compares with reality • Application of this methodology to Block Diagrams Analysis • Bibliography: – Chap. 5 “Ecological Economics”, Common & Stagl. Course Contents – T8 • Methods to compute primary energy for renewable electricity • EROI Course Contents – T8 • Learning Outcomes – Critically evaluate statistics and political goals on the weight of renewables on primary energy mixes at the country level. – Understand & apply the concept of EROI • Bibliography Chapter. 14 & 15 from “Energy and the Wealth of Nations”,Hall, C. & Klitgaard, K.. • 7th Practical Class – Exercises Course Contents – T8 • Energy & Economic Growth & Environment Course Contents – T8 • Learning Outcomes – Identify the interactions between energy use, economic growth and environmental quality • Bibliography: – Chap. 2 & 6 “Energy at the Crossroads” Smil, V. Course Contents – T9 • Life Cycle Assessment Bioethanol Life Cycle CO2 Bioethanol DDG • 8th Practical Class – Exercises • Bibliography: Course Contents – T10 • Energy use in Transports Course Contents – T10 • Legislation • 9th Practical Class – Exercises • Learning Outcomes – Learn about factors that influence energy use in transports and strategies & technologies that reduce the energy use in and their environmental impact – Apply & understand the legislation on transports • Bibliography: – Chap. 5 “Energy Efficiency and the Demand for Energy Services” Danny Harvey Course Contents – T11 • Energy Audits – Measurements – Mass and Energy Balances – Equipments • 10th Practical Class – Visita de Estudo (no Tagus Park) Course Contents – T12 • Tools to Model the Supply and Demand of Energy • 11th Practical Class – Exercises • Learning Outcomes – Learn about the energy modeling softwares & their usefulness Energy Balance in Closed Systems Energy Change = Heat + Work dE d U E p Ec Q W dt dt Energy change in the system Flows at the boundaries • 1st Law: Energy Conservation • U, Ec and Ep • Energy transfer by Heat • Energy transfer by Work • Sign of heat and work fluxes • Steady state vs. Transient heat work Energy Balance in Closed Systems • Choosing the boundaries – Flows, Thermodynamic System, Steady vs. Transient state – flows at the boundaries? Energy Balance in Closed Systems • Choosing the boundaries – Flows, Thermodynamic System, Steady vs. Transient state Energy Balance in Closed Systems • Exercise: Energy Balance in Closed Systems • Thermodynamic Cycles • 1st Law efficiencies Power Cycle Refrigerator & Heat Pump Cycles – Power Cycle Wcycle Qin – Heat Pump Qout Wcycle – Refrigerator Qin Wcycle Energy Balance in Closed Systems • Exercise (Homework) W Fdx P. Adx P.dV – If P is constant then W P V f Vi Vf – If PV is constant then W PV i i ln Vi Energy Balance in Closed Systems • Exercise (Homework) • Exercise: – Why is it possible that 1 ? – How much does the electricity of your fridge costs in a month? Energy Balance in Open Systems Mass Change = Mass Flows dm min,i mout , j dt i j Energy Change = Heat + Work + Energy in Mass Flow v j2 vi 2 dE Q W min ,i hi gzi mout , j h j gz j dt 2 2 i j Enthalpy of component j hi ui pi vi Flows at the boundaries Energy Balance in Open Systems • Exercises – – – – 1º Write the energy balance eq. 2º Identify energy flows 3º Simplify the eq. For incompressible liquids at constant pressure: h c T c water at 50ºC 4.182 kJ/kg.K Energy Balance in Open Systems • Turbines: – Produce work as a result of gas or liquid passing through a set of blades attached to a shaft free to rotate v j2 vi 2 dE Q W min ,i hi gzi mout , j h j gz j dt 2 2 i j Electricity from Epot of the water Electricity from Ekin of the wind Wmec from Ekin of the wind Hydraulic Turbine Wind Mill Wind Turbine Energy Balance in Open Systems • Turbines: – Produce work as a result of gas or liquid passing through a set of blades attached to a shaft free to rotate v j2 vi 2 dE Q W min ,i hi gzi mout , j h j gz j dt 2 2 i j Electricity from Epot of the water Electricity from Ekin of the wind Wmec from Ekin of the wind Hydraulic Turbine Wind Mill Wind Turbine Energy Balance in Open Systems • Exercises – Write the energy balance eq. – Identify energy flows – Simplify the eq. Castelo de Bode dam •3 turbines • medium water fall 80 m •Installed power: 159 MW •Medium annual electricity production: 390 GWh • What is the energy conversion taking place? Energy Balance in Open Systems • Exercises – Write the energy balance eq. – Identify energy flows – Simplify the eq. Castelo de Bode dam •3 turbines • medium water fall 80 m •Installed power: 159 MW •Medium annual electricity production: 390 GWh • Potential energy is converted into electricity and kinetical energy Energy Balance in Open Systems • Compressors (gas) & Pumps (liquids): Reciprocating Compressor – Used in aircraft engines, water pumping, natural gas transport, etc – Increase the pressure of a gas (compressor) or move fluids or Increase in pressure of gas slurries (pumps) using work obtainned from decreasing volume (obtainned with work) v j2 vi 2 dE Q W min ,i hi gzi mout , j h j gz j dt 2 2 i j Pump water using work Pump water using human work Treadle Pump Pumps Energy Balance in Open Systems • Compressors (gas) & Pumps (liquids): Reciprocating Compressor – Used in aircraft engines, water pumping, natural gas transport, etc – Increase the pressure of a gas (compressor) or move fluids or Increase in pressure of gas slurries (pumps) using work obtainned from decreasing volume (obtainned with work) v j2 vi 2 dE Q W min ,i hi gzi mout , j h j gz j dt 2 2 i j Pump water using work Pump water using human work Treadle Pump Pumps Energy Balance in Open Systems • Exercises – – – – 1º Write the energy balance eq. 2º Identify energy flows 3º Simplify the eq. Ideal gas model: Underground storing of natural gas in Carriço Storing Pressure: 180 bar Storing capacity: 2 155 GWh PV NRT u u (T ) h c T c CH 4 2.226 kJ/kg.K – The need to cool after compression Energy Balance in Open Systems • Heat Exchangers: – Used in power plants, air conditioners, fridges, liquefication of natural gas, etc – Transfer energy between fluids at different temperatures v j2 vi 2 dE Q W min ,i hi gzi mout , j h j gz j dt 2 2 i j Direct Contact Heat Exchanger Counter-flow Heat exchanger Direct Flow Heat Exchanger Energy Balance in Open Systems • Heat Exchangers: – Used in power plants, air conditioners, fridges, liquefication of natural gas, etc – Transfer energy between fluids at different temperatures v j2 vi 2 dE Q W min ,i hi gzi mout , j h j gz j dt 2 2 i j Direct Contact Heat Exchanger Counter-flow Heat exchanger Direct Flow Heat Exchanger Energy Balance in Open Systems • Exercises (homework) – 1º Write the energy balance eq. – 2º Identify energy flows – 3º Simplify the eq. Liquefaction of natural gas T=-162ºC Decrease in volume: 1/600 • Discuss boundaries Power cycle revisited • Coal power plant: Power Cycle Refrigerator The state variable: Entropy • Entropy is the state variable that gives unidirectionality to time in physical processes ocurring in isolated & adiabatic systems. – Hot coffee in a cold room gets colder and not hotter – Radiating energy is received by the Earth from the sun and by outer space from the earth and not the other way around. – If the valve of the tyre is opened, air gets out and not in Entropy Balance in Closed Systems Entropy Change = Entropy transfer in the form of heat + entropy production Not relevant for entropy balance It is not a flow at the boundary dS Q dt T Flows at the boundaries work Entropy change in the system • Meaning of • 2st Law: • >0 • In adiabatic systems… • Entropy transfer by Heat & sign • Steady state vs. Transient heat Entropy Balance in Closed Systems • 2nd Law: In an adiabatic system the entropy must not decrease • Suppose the system is adiabatic and that T2>T1 dS 0 dt dS dS1 dS2 Q Q 0 dt dt dt T1 T2 T2 dS 0 dt dS dS1 dS2 Q Q 00 dt dt dt T1 T2 T1 • 2nd Law: the arrow of time T2 T1