How low should be the energy required by a nearly Zero-Energy Building? The load/generation energy balance of Mediterranean housing

• Published in: Energy and buildings Vol. 61; pp. 161 - 171
• Main Authors: Oliveira Panão, Marta J.N., Rebelo, Miguel P., Camelo, Susana M.L.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 01.06.2013; Elsevier
• Subjects: Applied sciences; Bioclimatic building; Building stock; Building technical equipments; Buildings; Buildings. Public works; Cost-optimal; Energy management and energy conservation in building; Environmental engineering; Exact sciences and technology; Housing; Load/generation balance; Mediterranean; Nearly Zero-Energy Building; Regulation. Standardization; Residential building; Types of buildings; ANE, Portugal; MED; Nearly Zero-Energy Building; Cost-optimal; Mediterranean; Building stock; Housing; Load/generation balance; Energy analysis; Statistics; Energy balance; Requirement; Energy requirement; Low energy building; European directive; Cost analysis; Mediterranean region
• ISSN: 0378-7788
• DOI: 10.1016/j.enbuild.2013.02.031

[Display omitted] ► Currently housing primary energy loads, for regulated uses, are below 90kWh/(m2year). ► For regulated uses, housing primary energy loads are ‘low’ for 70kWh/(m2year). ► For total uses, housing energy loads are ‘low’ in the range of 100–110kWh/(m2year). ► Primary energy indicators from EN 15603 are applied. ► Regulated uses are heating, cooling and domestic hot water. Directive 2010/31/EU adopted that by the end of 2020 all new buildings should be nearly Zero-Energy Buildings (nZEB) and Member States should achieve cost-optimal levels by ensuring minimum energy performance requirements for buildings. This paper discusses how low should be the energy required by a nZEB, in the context of housing energy consumption in a Mediterranean climate (Lisbon). For selected houses built after 1990, the calculated primary energy loads for regulated uses – heating, cooling and domestic hot water – are found to be below 90kWh/(m2year). Applying the cost-optimal solutions of thermal insulation and glazing type and considering energy efficiency improved systems, this study concludes that housing energy loads are ‘low’ for the indicative range of 70kWh/(m2year) for regulated uses or 100–110kWh/(m2year) for total uses, taking primary energy indicators (PEI) from EN 15603. Assuming PEI from Passive House Planning Package or those to be assumed in Portugal for 2013, the threshold decreases to 60kWh/(m2year) for regulated uses or 90–100kWh/(m2year) for total uses. Only the first nZEB condition is explored by this paper. The second condition requires that the nZEB energy load is covered by a ‘significant’ part of renewable energy sources produced on-site or ‘nearby’.