Università degli studi di Cassino e del Lazio Meridionale Facoltà di Ingegneria Energetica Mente Energy sustainability Energy diagnosis of schools Academic Year 2013-2014
Environmental sustainability: climate The superficial average temperature has increased of 0.74 (±0.18 °C) from1906 to 2005. 11 of the last12 years(1995-2006) has been amongst the12 in the rank of the warmest years since1850. Fonte: Report of the Intergovernmental Panel on Climate Change, 2007
Energetic • Since the Second World War the incredible amount of low cost energy has created the illusion of an unlimited availability of the energy resources. The first awareness of this illusion started since the’70s due to the petrol crisis, when there was a deep rise of the cost of the oil. • Consequently there was an increasing interest in “Energetic”, a subject concerning a rational use of energy. • To face up correctly the problematic regarding energy is necessary taking in consideration: • The environmental impact of these energy systems (greenhouse effect, pollution, …); • The economic sustainability of energy consumptions; • The social availability of energy (population growth, increasing consumes of emergent Countries, politic implications).
Forms of energy • In thermodinamic studies there is an important distinction between the forms of energy in movement through the borderline of a system • Heat • Work • The forms of energy collected in a system: • mechanical energy, associated with potential energy end cinetic energy; • electric energy; • chemical energy; • nuclear energy; • heat energy.
Energy sources (renewable and not) • Among the energy resources of our planet, we can make the difference between renewable resources and non renewable resources: the first ones have the ability to continually renew during the time, while the second ones will not be available once consumed. • Energy sources available on our planet manifest themselves such as: • hydraulics energy (mechanical) • Energy of the tides (mechanical) • wind energy (mechanical); • solar energy (elettromagnetic); • geothermal energy (heat); • nuclear energy • Energy from biomasses (chemical)); • Energy from fossils (chemical)
Consumptions caused by central heating of buildings • In Italy more than1/3 of the annual energy basic necessities is used for the heating of civil and industrial buildings. • The energy consumption is about 45 Mtep/years which causes an emission of CO2 for about120 millions of tons/year • In the last 20 years the consumption of energy has been stable in the residential sectors, while it has doubled in the tertiary sector. • The methods of the consumptions have radically changed with a drop in the use of diesel oil and an increase in the one of natural gas. • Recently market focuses its attention on combustibles from biomasses and on renewable sources. • The energy consumption of scholastic buildings is about1 Mtep/years, whose 77% for central heating and 23% for electrical energy.
Equation of balance $ in entrance + $ generated= $ in exit + $ stocked + $ destroyed
Energy performance • A way to value the energy performance of a building are the basic necessities of primary energy, linked to the area of the building or to its volume • The energy performance of a building is given by the parameter EPgl. EPgl= EPi + EPacs + EPe + EPill
Consumptions and energy performances typical of a building in the residential area Italian buildings have the lower energy consumption per mq among those developed, but one of the highest specific consumption per day-degree. Probably low consumptions are due to mild temperatures, but our buildings are not well caulked or heating is not managed properly
parameters of influences Energy performances are influenced by: Typology of building(S/V, thermal bridges, orientation, ..); Thermal isolation of the building; Air impermeability; Regulation, distribution, emission and generation systems. Consumptions and energy performances typical of a building in the residential area typologies of consumptions energy consumptions are mostly caused by: Gas • Central heating; • Production of hot water; • cooking Electric energy: • Household electrical appliances • lights • Air conditioning Tipologie di consumi Parametri di influenza delle prestazioni energetiche
Whatwillhappen in the future? Main obstacles • Nimby (Not In My BackYard) • Ideology choices despite of technical ones (eg. Nuclear) • Renewable costs too high • Delayed of the comeback of investments • Micro-economic aspects privileged instead of macro-economic ones Main strategies • Energy savings • Diversification of the sources and promotion of renewable sources • Rationalising of the final uses • Technological improvements • Energy-environmental culture • Strategic role of research