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The paper presents the ventilated facades as an intervention for efficient energy upgrade of new and, mainly, existing buildings. It focuses on the requirements that this specific building element should fulfill, with regard to legal, technical, social and financial aspects. More specifically, legal aspects concern mainly the regulations that determine the element's behaviour with respect to the hygrothermal, energy, sound and fire performance, as well as other legal restrictions (i.e. urbanism/planning rules or listed buildings). The technical aspects involve structural issues, architectural concerns and aesthetics, as well as functional matters. Finally, the social aspects refer to the acceptance of the element by building users and architects/engineers, while the financial aspects interrelate the ownership with the economic incentives and the investment feasibility. All the above are presented and discussed in the paper in order to highlight the applicability of ventilated façade systems in residential buildings. [ABSTRACT FROM AUTHOR]

Abstract: Heat transfer through windows accounts for a significant proportion of energy used in the building sector for covering both heating and cooling needs, since the optical and the thermal characteristics of conventional fenestration products constitute them more “vulnerable” in energy flows when compared to opaque building elements. In this study, an approach for evaluating the cooling energy performance of residential windows is presented. It is based on a parametric study, which aims at highlighting the impact of the window configuration on its energy behavior in terms of geometrical characteristics, thermophysical and optical properties, as well as orientation and shading levels. The results underlined the magnitude of the relationship between the thermal and optical properties of the transparent elements with respect to their orientation; especially for residential buildings, the solar transmittance determines at a considerable extent the cooling energy performance of fenestration, at least in the warmest part of Europe. Furthermore, the statistical analysis of the derived data provided mathematical expressions, which can be used in praxis for predicting the cooling energy performance of windows with respect to their thermal and optical characteristics. [Copyright &y& Elsevier]

Nowadays, subjects such as eco-design requirements, product rating or code compliance with regard to energy efficiency are expanding towards a pan-European level. This leads to the necessity of defining zones within the European region, which share common climatic characteristics and will further facilitate the quick estimation of building energy performance. Towards this direction stands the current paper; it presents an approach for defining climatic zones in Europe on the basis of the amount of heating and cooling degree days. It is applied for the climate classification of selected European cities and is compared with the conventional scheme based solely on heating degree days. Since the approach is orientated mainly towards the assessment of building energy performance, its outcomes are evaluated with regard to the actual heating and cooling energy needs of a reference building unit with office use located in representative cities of the proposed climatic zones and facing the four cardinal orientations. The classification of climatic zones on the basis of both heating and cooling degree days leads to more realistic results, since nowadays cooling needs form a substantial part of the energy balance of the building, especially in the Mediterranean regions. [ABSTRACT FROM AUTHOR]