Gestão de Sistemas Energéticos

2017/2018

Introdução

Classe # 1

Prof. Tânia Sousa

taniasousa@tecnico.ulisboa.pt

Docentes

• Tânia Sousa– taniasousa@tecnico.ulisboa.pt

• Mário Costa– mcosta@tecnico.ulisboa.pt

• Tiago Domingos– tdomingos@tecnico.ulisboa.pt

Avaliação

• 3 Testes ou 1 Exame (média dos 3 testes ou

exame têm nota mínima de 9.5val.)– Repescagem de 1 teste na data de exame

• Trabalho individual de auditoria aos consumos

energéticos domésticos que pode valer no

máximo 2 valores (opcional)– Preparation an Planning

– Facility inspection

– Field work

– Data analysis

– Reporting

– Energy Action Plan

Aulas

• Slides das aulas teóricas e exercícios das aulas

práticas serão postos no fénix

• Aulas práticas começam dia 21 de Fevereiro

Objectivos da UC

1. Compreender e modelar os fluxos energéticos

à escala do país, à escala sectorial e 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.

Sistema Energético

• Tem como objectivos satisfazer necessidades

energéticas da sociedade:

• Embodied Energy is the sum of all the energy

required to produce any goods or services

Embodied Energy

Material Energy MJ per kg

Bricks (common) 3

Steel (general, av. recycled content) 20.1

Stainless steel 56.7

Cork insulation 26

Aluminium (general & incl 33%

recycled)155

PVC (general) 77.2

Wallpaper 36.4

Iron (general) 25

Copper (average incl. 37% recycled) 42

Lead (incl 61% recycled) 25.21

Ceramic sanitary ware 29

Paint - Water-borne 59

Paint - Solvent-borne 97

Energy Analysis

• The process of determining the embodied

energy of a product or service, i.e., the energy

required directly and indirectly to produce it

– The energy used indirectly might be more

important that the energy used directly

Auto-industry assembly line

Electricity

Paint

Embodied energy in a car: 270 GJ

Sistema Energético

• Formas de energia útil:

Cullen and Allwood, 2010

From useful energy to energy services

• Passive systems: where useful energy is

delivered into and mostly lost as unwanted

heat, in exchange for energy services such as

thermal comfort, illumination and transport

(Cullen et al., 2011).

10

Sistema Energético

• Transformação de Energia

Cullen and Allwood, 2010

Energy efficiencies

• First Law Efficiency

Relevant energy output Relevant energy input

Heat and Work - Joule’s Experiment

• Equivalence between Heat (Q) and Work (W)

Is the first law enough?

• What has the first law has to say about what

happens in the following case?

Energy vs. Exergy

160ºC 25ºC

Potential Work = 34 MJ Potential Work = 1.8 MJ

environment

20ºC

Energy = 105 MJ Energy = 105 MJ

Exergy = 34 MJ Exergy = 1.8 MJ

Exergy efficiencies

• Second Law efficiencies

• Exergy analysis: (mis)match between energy

used and end-use

Moran et al., 2014

Ts=2200K

=100%

From Primary Energy to Energy

Services

Sankey Diagrams

• Sankey Diagrams: a flow diagram used to

represent flows of mass (water, CO2, etc) or

energy or money or ... by arrows where the

thickness of arrows are proportional to the

amount

Miguel Águas (2009)19

Energetic Systems

0

2

4

6

8

10

12

14

16

18

20

18501860187018801890190019101920193019401950196019701980199020002010

Final exergy / GDP

Useful exergy /

GDP

Exe

rgy /

GD

P (

MJ/2

01

0€

)

Serrenho, A. C., B. Warr, T. Sousa, R.U. Ayres, T. Domingos (2016). Structure and dynamics of useful work along the agriculture-industry-services transition: Portugal from 1856

to 2009. Structural Change and Economic Dynamics, 36, 1-21.

Final and Useful Exergy Intensities –

Portugal 1856 to 2009

Energy & Economic Growth

Escassez vs. Substitubilidade

Murphy, 2013

Energia - Impactos Ambientais

Densidade Energética

Energy Management

Class # 9 : Energy Economics

Links Energy-Economy-Environment

• What will the economy in the future look like?

More self-reliant local economies

and ways of life

Global Economy dependent on

renewable energies

Similar to the present but biggerModels will help us understand

the impact of energy supply &

technological innovations &

policy measures on the

environment and the economy?

Sistema Energético Portugal 2010

Industry

DEMAND

Transports

Electricity

PrimaryEnergy

Non-Renewable

Current paradigm

PrimaryEnergy

Non-Renewable

Renewable

Industry

DEMAND

PrimaryEnergy

Non-Renewable

Renewable Heating

Cold

Electricity

Transportes

• Energy as a service

• Energy Efficiency

• Distributed “Production”

• Environmentally friendly

• Quality of service

• Demand side

management

• The power of the

individual options

Emerging Paradigm

Paradigm Change

Energy use in Industry

• Industrial energy intensity for materials

Gutowski TG, Sahni S, Allwood JM, Ashby MF,Worrell E. 2013 The energy required to produce

materials: constraints on energy-intensity improvements, parameters of demand. Phil Trans R Soc A

371: 20120003.

http://dx.doi.org/10.1098/rsta.2012.0003

Steel

Cement

Paper

Aluminium

Plastics

Gestão de Energia

Slide 33 of 53

Energy use in Buildings

Foam insulation

The most highly insulated houses

have a heat transfer coefficient of

U=0.1-0.2 W/m2/K

Blown-in cellulose

insulation (fills the gaps)

Vaccum insulation panels

Cork 0.06-0.07 W/m/K

Energy use in Transport

Primeira aula prática

• How much energy does your electric heater that

has a power of 2000W spends in 1 hour?

• Convert it to Joules

Per capita energy use

kW/capita GJ/capita

Region 1990 2008 1990 2008

USA 10.2 10.0 320.5 314.0

EU-27 4.6 4.7 144.9 147.0

Middle East 2.2 4.0 69.9 125.2

China 1.0 2.1 31.8 67.0

Latin America 1.3 1.6 40.6 51.9

Africa 0.8 0.9 25.5 28.1

India 0.5 0.7 15.9 22.6

Others* 2.9 2.7 90.8 85.9

The World 2.2 2.4 69.9 76.6

Electricity tarifs