The majority of Italian schools (70%) were built in the absence of any legislation related to energy efficiency, and therefore have very low energy performance due to aging or poor quality of construction. An energy retrofit of this building stock is needed to meet the current European goals on greenhouse gas emission reduction. The retrofit is also needed in order to guarantee adequate comfort levels in indoor spaces and good conditions for learning and educational activities, that are often not reached in poor quality constructions. This work presents the results of an interdisciplinary study related to the energy requalification of a school located in Ostia, near Rome in Italy, built in the 1960s with a steel structure and Eternit infill. The scope of the analysis is to verify the economic and environmental effectiveness of four proposed retrofit interventions concerning the replacement of fixtures and the installation of an insulating coat. The current thermal transmittance of the walls was evaluated through thermofluximetric measurements conducted in situ; dynamic simulations were performed to determine the current energy performance and the energy performances following the four proposed retrofit scenarios. Energy and carbon payback times were evaluated (by means of the life cycle analysis (LCA) approach) and the economic value was determined for each of the four proposed retrofits, using a probabilistic approach. The results show that the replacement of windows is the most convenient intervention from all points of view. The study provides evidence that an assessment of schools’ energy retrofits should include both economic and life cycle aspects.
Green roofs have a thermal insulating effect known since ancient times. In the building sector, green roofs represent a sustainable passive solution to obtain energy savings, both during winter and summer. Moreover, they are a natural barrier against noise pollution, reducing sound reflections, and they contribute to clean air and biodiversity in urban areas. In this research, a roof-lawn system was studied through a long experimental campaign. Heat-flow meters, air and surface temperature sensors were used in two buildings characterized by different surrounding conditions, geometries and orientations. In both case studies, the thermal behaviors of the roof-lawn system were compared with the conventional roofs. In addition, a dynamic simulation model was created in order to quantify the effect of this green system on the heating and cooling energy demands. The roof-lawn showed a high thermal inertia, with no overheating during summer, and a high insulating capacity, involving energy savings during winter, and consequently better indoor thermal conditions.
The growing attention to sustainability and life cycle issues by European and international policies has recently encouraged the adoption, in the construction sector, of environmental labels able to quantify the impacts on environment associated with the fabrication of several building materials, e.g., their embodied energy and carbon. Within this framework, since walls represent a large percentage of building mass and therefore of embodied impacts, this article collects and analyzes nearly 180 Environmental Products Declarations (EPDs) of wall construction products such as masonry blocks and concrete panels. The data related to the primary energy (renewable and non-renewable) and the global warming potential extracted from the EPDs were compared firstly at the block level (choosing 1 kg as functional unit), enabling designers and manufacturers to understand and reduce the impacts from wall products at the early design stage. As the design progresses, it is therefore necessary to evaluate the environmental impacts related to the entire wall system. For this purpose, this paper proposes a further investigation on some simple wall options having similar thermal performance and superficial mass (the functional unit chosen in this case was equal to 1 m2 with R ≈ 5 m2K/W, Ms ≈ 260 kg/m2). The outcomes showed how the durability of the materials and the potential of disassembly of the wall stratigraphies can play a crucial role in reducing the environmental impact. This paper provides a methodological reference both for manufacturers to reduce impacts and for designers committed to the application of environmental labeling in the design process since they will now be able to compare their products with others.
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