Gestão de Energia: 2013/2014

1. Gestão de Energia: 2013/2014 Introduction &Review of ThermodynamicsClass # 1 Prof. Tânia Sousataniasousa@ist.utl.pt

2. Docentes • Tânia Sousa • taniasousa@ist.utl.pt • Carla Silva • carla.silva@ist.utl.pt • Carlos Silva • carlos.santos.silva@ist.utl.pt • André Pina • andre.pina@ist.utl.pt

3. 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

4. Objectivo • Compreender e modelar os fluxos energéticos à escala do país, em sistemas industriais, em edifícios ou equipamentos complexos. • Definir acções que permitam racionalizar o uso da energia, quantificando os benefícios económicos e ambientais destas acções.

5. Gestão de Energia: Conteúdo 4ª feira à tarde 4ª feira manhã e à tarde

6. 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

7. Course Contents – T2 • The Portuguese Energetic Balance: • Supply, Conversion & Demand • Energy Carriers

8. 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.

9. Course Contents - T3 • From Primary Energy to Energy Services at different scales IAASA - Global Energy Assessment 2012

10. Course Contents - T3 • World and national patterns of energy use • Energy Transitions Energy Transition Energy Transition biomass to coal coal to oil Grubler, A. “Energy Transitions”

11. Course Contents - T3 • Sankeydiagrams for differentscales • 1stand 2ndLawEfficiencies

12. Course Contents – T3 • 2ndPraticalClass& 1stassignment • EachgroupdrawstheSankeydiagramusing e-Sankey for the PEB for a specificyear for Portugal • Learningoutcomes: • Understandconceptsofprimary, final & usefulenergy • Historical perspective onworldenergy use & transitions • Use Sankeydiagrams to analyseenergysystems • Understand1stand 2ndlawefficiencies • 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.

13. 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.

14. 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

15. 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

16. Course Contents – T6 • Energy use in Buildings • Factors controlling energy use in buildings • Techniques to reduce energy use:

17. Course Contents – T6 • RCCTE & RSECE: Energy efficiency in buildings • 5thPracticalClass • Exercises • LearningOutcomes • Learnaboutstrategies to reduceenergy use in buildingsandtheirimpact • Apply& understandtheRCCTE & RSECE • Bibliography: • Chap. 4 “Energy Efficiency and the Demand for Energy Services” DannyHarvey • Decreto-lei n.º 118/2013

18. 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 yearsbased on changes in the economic structure & compares with reality • Application of this methodology to Block Diagrams Analysis • Bibliography: • Chap. 5 “Ecological Economics”, Common & Stagl.

19. Course Contents – T8 • Methods to compute primary energy for renewable electricity • EROI

20. 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

21. Course Contents – T8 • Energy & Economic Growth & Environment

22. 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.

23. Course Contents – T9 • LifeCycleAssessment • 8thPracticalClass • Exercises • Bibliography: Bioethanol Life Cycle CO2 Bioethanol DDG

24. Course Contents – T10 • Energy use in Transports

25. 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

26. Course Contents – T11 • EnergyAudits • Measurements • MassandEnergy Balances • Equipments • 10thPracticalClass • Visita de Estudo (no Tagus Park)

27. Course Contents – T12 • Tools to ModeltheSupplyandDemandofEnergy • 11thPracticalClass • Exercises • LearningOutcomes • Learnabouttheenergymodeling softwares & theirusefulness

28. Energy Balance in Closed Systems Energy Change = Heat + Work Flows at the boundaries Energy change in the system work • 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

29. Energy Balance in Closed Systems • Choosing the boundaries • Flows, Thermodynamic System, Steady vs. Transient state – flows at the boundaries?

30. Energy Balance in Closed Systems • Choosing the boundaries • Flows, Thermodynamic System, Steady vs. Transient state

31. Energy Balance in Closed Systems • Exercise:

32. Energy Balance in Closed Systems • Thermodynamic Cycles • 1st Law efficiencies • Power Cycle • Heat Pump • Refrigerator PowerCycleRefrigerator &HeatPumpCycles

33. Energy Balance in Closed Systems • Exercise (Homework) • If P is constant then • If PV is constant then

34. Energy Balance in Closed Systems • Exercise(Homework) • Exercise: • Whyisitpossiblethat ? • Howmuch does theelectricityofyourfridgecosts in a month?

35. Energy Balance in Open Systems Energy Change = Heat + Work + Energy in Mass Flow MassChange =  MassFlows Enthalpy of component j Flows at the boundaries

36. 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:

37. 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 Electricity from Epot of the water Electricity from Ekin of the wind Wmec from Ekin of the wind Wind Mill Hydraulic Turbine Wind Turbine

38. 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 Electricity from Epot of the water Electricity from Ekin of the wind Wmec from Ekin of the wind Wind Mill Hydraulic Turbine Wind Turbine

39. Energy Balance in Open Systems • Exercises • Writetheenergybalance eq. • Identifyenergyflows • Simplifytheeq. • Whatistheenergyconversiontakingplace? Castelo de Bode dam • 3 turbines • medium water fall 80 m • Installed power: 159 MW • Medium annual electricity production: 390 GWh

40. Energy Balance in Open Systems • Exercises • Writetheenergybalance eq. • Identifyenergyflows • Simplifytheeq. • Potentialenergyisconvertedintoelectricityandkineticalenergy Castelo de Bode dam • 3 turbines • medium water fall 80 m • Installed power: 159 MW • Medium annual electricity production: 390 GWh

41. Energy Balance in Open Systems • Compressors (gas) & Pumps (liquids): • Used in aircraft engines, water pumping, natural gas transport, etc • Increase the pressure of a gas (compressor) or move fluids or slurries (pumps) using work Reciprocating Compressor Increase in pressure of gas obtainned from decreasing volume (obtainned with work) Pump water using work Pump water using human work Treadle Pump Pumps

42. Energy Balance in Open Systems • Compressors (gas) & Pumps (liquids): • Used in aircraft engines, water pumping, natural gas transport, etc • Increase the pressure of a gas (compressor) or move fluids or slurries (pumps) using work Reciprocating Compressor Increase in pressure of gas obtainned from decreasing volume (obtainned with work) Pump water using work Pump water using human work Treadle Pump Pumps

43. Energy Balance in Open Systems • Exercises • 1º Writetheenergy balance eq. • 2º Identifyenergyflows • 3º Simplifytheeq. • Ideal gasmodel: • Theneed to cool aftercompression Underground storing of natural gas in Carriço Storing Pressure: 180 bar Storing capacity: 2 155 GWh

44. 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 Direct Contact Heat Exchanger Counter-flow Heat exchanger Direct Flow Heat Exchanger

45. 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 Direct Contact Heat Exchanger Counter-flow Heat exchanger Direct Flow Heat Exchanger

46. Energy Balance in Open Systems • Exercises (homework) • 1º Write the energy balance eq. • 2º Identify energy flows • 3º Simplify the eq. • Discuss boundaries Liquefaction of natural gas T=-162ºC Decrease in volume: 1/600

47. Power cycle revisited • Coal power plant: Power Cycle Refrigerator

48. 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

49. 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 Flows at the boundaries Entropy change in the system work • Meaning of  • 2st Law: • >0 • In adiabatic systems… • Entropy transfer by Heat & sign • Steady state vs. Transient heat

50. 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 • 2nd Law: the arrow of time T2 T1 T2 T1