Towards the implementation of the Passive houses in the Portuguese context

L. Brotas1, G. Carrilho da Gra^a2, H. Gonsalves1*, M. Lerer2 and P. Paredes2

1 INETI, Department of Renewable Energy, Campus do Lumiar do INETI, 1649-038 Lisbon, Portugal
2 Natural Works, Rua Ricardo Espnito Santo N7 CV-E, 1200-790 Lisbon, Portugal
* Corresponding Author, helder. goncalves@ineti. pt

Abstract

Achieving a pleasant indoor environment with low energy consumption is a major goal of good building design. Overheating, in particular, is a problem in southern European climates, where several approaches to achieving comfortable indoor conditions, while keeping the building’s energy consumption low, have been successfully established. The Passivhaus standard, developed in Germany, defines requirements for very-low energy homes with regards to space heating. The strategies adopted in cold climates consist of a highly insulated envelope combined with reduced air losses and a mechanical ventilation system with heat recovery. This approach reduces the heating needs and high thermal comfort levels can be achieved with improved energy efficiency. The Passive-On project has taken this concept further by also looking at the warmer European climates where the cooling loads may become a major issue. The project consortium has therefore formulated a revised proposal for the application of the standard to those climates. This paper presents part of the results of this European funded project.

Keywords: Low energy buildings, Passivhaus, passive cooling, adaptive comfort

1. Introduction

In Europe, buildings are responsible for 40% of the final energy consumed. In Portugal, this percentage is lower, 17% domestic and 12% services (2006). However, the energy consumption is still increasing, in particular related to cooling systems. Within this context, the European Commission presented the directive EPBD which focused on the energy performance in buildings. Moreover, recent concerns about the security of the energy supply and the rising price of oil, make energy efficiency a top priority, as well as to diversify the energetic resources, promoting the adoption of renewable energies to reduce the exterior energy dependency and GEE emissions. [1]

More broadly, the European Parliament resolution of 31 January 2008 on an Action Plan for Energy Efficiency: Realising the Potential “calls on the Commission to propose a binding requirement that all new buildings needing to be heated and/or cooled be constructed to passive house or equivalent non-residential standards from 2011 onwards, and a requirement to use passive heating and cooling solutions from 2008”. [2]

Other countries of Europe have standards such as the Code of Sustainable Homes in England and Wales where level 5 corresponds to the Passivhaus standard, to be enforced by 1912. This standard also requires all homes to be zero carbon (level 6) by 2016, having to produce on-site energy. [3]