Costanzo Di Perna

Thermal performance of an insulated roof with reflective insulation: Field tests under hot climatic conditions

The use of reflective insulation materials in buildings, for energy saving in summer, has been spreading in southern Europe. These products are not typical of the local building context. There is a lack of well-established measurement systems for reflective insulation thermal transmittance. The aim of this article is to understand whether a reflective insulation material could be effective in hot and temperate climate, also compared with other roof solutions. For this purpose, we compared the thermal performance of a roof with and without reflective insulation, both installed in a full-scale experimental building near Ancona (Italy) in the summer period. The results showed that the reflective insulation benefits are quite limited when using the insulation level imposed by actual laws, which consider insulation as the main strategy for energy saving in temperate and hot climates.

A field study of thermal inertia of roofs and its influence on indoor comfort

Many of the current European Member States regulations on energy saving in buildings seem to follow North European trends that call for high insulation of the envelope. However, this kind of set-up overlooks some specific elements that are necessary to build typical buildings in warmer climates. Thermal inertia on the internal surface of the envelope has traditionally been used in such contexts not only to contain solar gains but also to protect against cold winter because of its capacity to store and to slowly release energy. This research investigates how thermal inertia on roof slabs could positively affect the comfort indoors, also in buildings that tend towards being nearly zero-energy buildings, as suggested by last European Directive 2010/31/EU. With this aim, an experiment was conducted on a full-scale building with different roofs, on light and heavy slabs, under hot and moderate climatic conditions (Ancona, Italy). The thermal performance of roofs was monitored during summer and winter seasons. In winter, the building was also subjected to cyclical internal heat gains. The experiment demonstrated that a certain thermal inertia in the slab guarantees better indoor comfort in both summer and winter, and it can also reduce energy consumption from heating.

Traditional Houses with Stone Walls in Temperate Climates: The Impact of Various Insulation Strategies

Many authors have carried out quantitative studies on the behaviour of traditional buildings in different seasons, showing the capacity of these buildings to secure indoor comfort by means of passive control systems. Experimental studies carried out on traditional houses in India (Dili et al., 2010) Korea (Youngryel et al., 2009), northern China (Wang & Liu, 2002), Japan (Ryozo, 2002), Nepal (Rijal & Yoshida, 2002), and Italy (Cardinale et al., 2010) are of particular interest.