The increase of the urban warming phenomenon all over the world is gaining increasing attention from scientists as well as planners and policymakers due to its adverse effects on energy consumption, health, wellbeing, and air pollution. The protection of urban areas from the outdoor warming phenomenon is one of the challenges that policy and governments have to tackle as soon as possible and in the best possible way. Among the urban heat island mitigation techniques, cool materials and urban greening are identified as the most effective solutions in reducing the urban warming phenomenon. The effects produced by the adoption of cool materials and urban forestation on the urban microclimate were investigated through a computational fluid-dynamic (CFD) model. The CFD model was calibrated and validated thanks to experimental surveys within the Catania University campus area. The urban microclimate thermal comfort analysis and assessment were carried out with the Klima–Michel Model (KMM) and Munich Energy Balance Model for Individuals (MEMI). In particular, three scenarios were performed: cool, low, and high levels of urban greening. The cool scenario, although it produces air temperature at around 1.00 °C, determines the worst condition of outdoor thermal comfort, especially at the pedestrian level. On the contrary, a high level of urban greening, obtained by the extensive green roofs together with an urban forestation, guarantees the wellbeing of pedestrians, showing more convenient values of PMV and PET.
The renewed attention paid to raw earth construction in recent decades is linked to its undoubted sustainability, cost-effectiveness, and low embodied energy. In Italy, the use of raw earth as a construction material is limited by the lack of a technical reference standard and is penalised by the current energy legislation for its massive behaviour. Research experiences, especially transoceanic, on highly performative contemporary buildings made with natural materials show that raw earth can be used, together with different types of reinforcements, to create safe, earthquake-resistant, and thermally efficient buildings. On the basis of experimental data of an innovative fibre-reinforced rammed earth material, energy analyses are developed on a rammed earth building designed for a Mediterranean climate. The paper focuses on the influences that different design solutions, inspired by traditional bioclimatic strategies, and various optimised wall constructions have in the improvement of the energy performance of the abovementioned building. These considerations are furthermore compared with different design criteria aiming at minimising embodied carbon in base material choice, costs, and discomfort hours. Results have shown the effectiveness of using the combination of massive rammed earth walls, night cross ventilation, and overhangs for the reduction of energy demand for space cooling and the improvement of wellbeing. Finally, the parametric analysis of thermal insulation has highlighted the economic, environmental, and thermophysical optimal solutions for the rammed earth envelope.
Sicily is characterized by rural buildings, Palmenti, destined to wine production, which are scattered along the countryside and part of the local historical heritage. There are different types of rural buildings, but all have in common the use of ancient and well-established bioclimatic techniques for wine conservation and aging. Most of them were built with the double function of living space for the owner and productive spaces for all the activities correlated to the cultivations. Indeed, many rural houses, destined to the wine production, are characterized by wineries and wine cellars (the first for the wine production, the second to store the wine for the aging process). The growing production of high-quality Sicilian wines, very appreciated all over the world, leads to upgrade the ancient Palmenti to seek optimal hygrothermal conditions and, therefore, to guarantee high performance of the produced and stored wines. The purpose of this study is to investigate how the retrofit measures taken to comply with the energy regulations could affect the thermal behavior of a wine cellar constructed with consolidated bioclimatic technics. The results show the importance of not insulating the solid ground floor for maintaining suitable temperatures for the fermentation and aging of wine. This study can be useful for future analysis when comparing the optimal hygrothermal conditions of wine cellars located in homogeneous viticultural areas (with same climate, geology, soil, physical features, and height) in other parts of the world.
The growing concern for the reduction of energy needs and the environmental impact of the building sector has placed emphasis on the possibilities offered by natural materials. The adoption of agricultural by-products seems to be promising and in line with the circular economy paradigm. Materials such as hemp and straw have been extensively adopted in contemporary construction, but nevertheless, the potential use of giant reed has not been sufficiently investigated despite being a common infesting plant abundantly available all over the planet. This work focuses on the performances assessment of lime/cement–reeds mixtures as base materials to design a new line of building components (bricks, blocks, panels and loose insulation) that can be used both in new bio-based construction and in existing buildings for energy-efficiency retrofit. The main materials used in the experimental campaign are giant reed by-products, lime, cement and local and recycled aggregates. The evaluation of the physical, mechanical and thermal properties of lime–reed and cement–reed composites are presented. The results of thermal conductivities (between 0.245 and 0.191 W/m K) and mechanical properties (compressive strengths between 0.848 and 1.509 MPa, and flexural strengths between 0.483 and 0.829 MPa) allow meeting the requirements for non-bearing and thermal building blocks. The outcomes show how blocks made with the abovementioned lime–reed mixture have good mechanical performance and thermo-physical behavior when compared to conventional building materials such as hollow clay or hemp blocks with the same thickness.