Strategies for the design of Net zero energy balance buildings Sustentabilidade energética e metabolismo urbano Strategies for the design of Net zero energy balance buildings Vítor Leal Lisboa, 07 de Julho de 2010 10 !

NZEB – The concept A building which is bidirectionally connected to the energy grids [/electric grid]. Which incorporates local microgeneration equipments such that On an annual basis the amount of energy that it injects in the grid(s) is at least equal to the one that it draws from them.

Challenges to Policy/Economy and Research Policy Context UK decided in 2007 that they would become mandatory for after 2016. Others followed. EU EPBD recast published on the 18th June 2010 calls requires (article 9) that (a) by 31 December 2020, all new buildings are nearly zero- energy buildings; and (b) after 31 December 2018, new buildings occupied and owned by public authorities are nearly zero-energy buildings. Challenges to Policy/Economy and Research

Challenges for Portugal (1) Definition and reference conditions adapted to the local conditions Definition of “energy from renewable resources produced nearby” Conversion factors to primary energy of the different carriers representative of Portuguese reality; Typical values for the building life-cycle to be considered in the economic studies.

The problem thus becomes one of Costs / Economy Strategies on how to achieve net-zero performance | the extremes: Design as usual (high consumption) and then install [a lot of] micro(?)generation to offset the consumption. Design for the lowest possible consumption and then [few] microgeneration will be needed to reach net-zero balance. Note that from the environmental point of view both approaches seem to be [apart from the use of materials] equally good ! The problem thus becomes one of Costs / Economy

[Initial or life-cycle] Optimal zone Cost [Initial or life-cycle] + Eficiency + Microgeneration

Furthermore, the scope of technologies that can be employed [Energy services @ building and micro-generation to offset the consumption] is large and “ever-growing”.

Challenges for Portugal (2) Need to develop tools to assist in choosing efficient / cost effective design, which may help to: 1. Correctly assess the building performance; 2. Identify for each specific building which are the combinations of ENVELOPE + ENERGY SERVICES + MICROGENERATION Technologies That are in the most cost/economic effective area. 3. Assist the Policy and Market forces to identify the clusters of technologies with most potential in Portugal and foster / support its development.

Other research issues raised by NZEBs: Potential contribution to the Energy balance of Portugal and comparison with other investment alternatives in EE&RE Impact / interaction on Electric Grids; Modern technologies of biomass for heating; Local offset / microgeneration vs. off-site Renewables. Potential contribution of Smartmetering to Energy Efficiency. Design of incentives to promote the measure.

Some ongoing Research work ongoing within the MPP in this area: Maria Kapsalaki: Carbon Neutral Buildings Design in Respect to Climate and Resource Diversity Gonçalo Cardoso: Building integrated micro-generation solutions for a sustainable built environment Isabel Azevedo: A study of NZEB from an energy systems perspective Ariovaldo Carvalho: Retrofitting opportunities for buildings in historical centers: balancing energy efficiency, sustainability and comfort. Pedro Gonçalves: Exergy Systems Analysis for High Performance Buildings

Slide plataforma Maria Kapsalaki

THANK YOU

EXTRAS

Comparative Analysis 15 Case Study Location Climate HDD (b18) Solar radiation horizontal (KWh/m2.yr) Floor Area (m2) Wall U-value (W/m2.K) Roof U-value (W/m2.K) Glazing U-value (W/m2.K) Building Ventilation Heating Needs (KWh/m2.yr) Electricity Needs (KWh/m2.yr) PV installed per building floor area(W/m2) Eco-Terra Quebec 4966 3 591 234 0.16 0.125 0.8 mech 37 33 12 Solar Harvest Colorado 3322 4 619 426 0.17 0.09 1.1 nat+mech 7 23 21 Tanno Weiz 3260 3 044 120 0.11 15 39 5 Crossway Eco Kent 2866 2 757 285 0.12 0.7 34 11 Solar Plus Haus Hessen 2865 2 575 212 - 12.6 2 Mariolopoulos Athens 1112 4 565 1267 0.25 0.26 1.0 nat 4 29 PVRES Florida 534 4 590 225 0.57 0.19 31 18

16 Comparative Analysis