• Energy Research

Global waste is expected to grow substantially by 2050, therefore, defining an effective waste management strategy is a crucial topic for both industry and academia. Nowadays, food and green waste, in particular, represent a large share of the total waste production. All this considered, effectively processing and eventually reusing materials such as waste cooking oil is of paramount importance. This study investigates the potential environmental impact and the primary energy consumption for three waste cooking oil valorization pathways i.e. biodiesel, direct burning fuel, additive for recycling aged-asphalt, as well as a new application, i.e. phase change material, compared to their specific more common alternative based on a cradle-to-gate approach. The aim is to identify and recommend the most advantageous alternative in terms of environmental impact. Results showed that the waste cooking oil has a lower impact in all comparisons made, except as phase change material. The less effective performance in some cases was compensated by the waste oil entry as a burden-free resource under an attributional model. The best profile of the waste cooking oil is as direct burning fuel. However, the binder asphalt substitution is highly recommended due to the nature of the application. The major obstacles to the waste cooking oil usage are the limited stock, composition and quality variability, and the difficulty of proper collection.

Italy's architectural heritage boasts numerous historic buildings, which are an integral part of the country's cultural fabric and public assets. However, these structures inevitably deteriorate over time and require various types of intervention, particularly to mitigate energy dissipation. Yet, retrofitting historic buildings poses a challenge as preserving their historical features requires non-invasive strategies. To address this challenge, the present study introduces the incorporation of an innovative geothermal system tailored for the energy retrofit of an Italian historic building. This innovative system respects the building's landscape and constraints due to the archeological status of the building. It consists of a hybrid heat pump connected to a gas boiler, interfacing with a geothermal field to leverage it as either a heat source or sink. An in-depth analysis of this system was conducted, first in a specialized laboratory to assess its performance and then following its installation inside the historic building, thus interfacing it with a historical context and a real geothermal field. Notably, the comparative evaluation of the Coefficient of Performance (COP) between laboratory simulations and real-world deployment revealed striking similarity, affirming the system's consistent performance across contexts. Moreover, for a comprehensive analysis of the system, a techno-economic evaluation was carried out, which highlighted the many advantages of this installation.

In this work, different phase change materials (PCMs) were stabilized in biochar and lignin by vacuum impregnation technique and later incorporated into gypsum panels in real building applications. We used three types of paraffin, with phase transition temperatures of 21, 27, and 31 degrees C, respectively, i.e., within the most common thermal comfort conditions in building applications and two bio-based porous matrices, lignin and biochar. In doing so, we aimed at producing and characterizing an environmentally friendly shape-stabilized material, to be easily integrated into gypsum-based building components. The obtained compounds were analyzed at various scales of investigations using Brunauer-Emmett-Teller (BET), Hot Disk, Fourier-Transform infrared (FT-IR) spectroscopy, Scanning Electron Microscopy (SEM), thermal cycling, Differential Scanning Calorimetry (DSC), and Thermogravimetric (TGA) analyses, to adequately assess the composites' thermophysical performance and long-term stability. The obtained results highlight the promising thermal buffer capability of the shape-stabilized samples, particularly in the case of the paraffin with a melting temperature of 21 degrees C, which obtained the highest impregnation rate. In general, all the compounds tend to lose PCM during cycling. However, significant leakage was only found above 100 degrees C, therefore, the samples show a relatively stable behavior for applications within the most common local boundary conditions in the built environment.

Abstract In recent years, a huge research effort aimed at developing adaptive materials for improving building indoor thermal comfort has been detected. Yet, only a few analytic and dynamic approaches have been implemented to predict building materials thermal performance. In this study, an analytic model is elaborated to evaluate the thermal performance of a well insulated case study prototype building equipped with a thermochromic envelope, and bench-mark it against cool-only and dark-only applications. Therefore, the effect of the selected thermochromic solutions on the indoor environment of the building in terms of surface and indoor air temperature is evaluated both in summer and winter conditions. Results show that the application of the thermochromic membrane and wall paint represents a win-to-win solution combining the well-established passive cooling effect of high reflectance materials in summer with desirable solar gains produced by dark surfaces in winter. Average indoor air temperature reductions up to 0.2 and 0.5 K were found in summer, while a 0.5 and 0.6 K increase was registered in winter, for the low and high insulation configuration, respectively, when compared to more common dark and cool solution.

In response to the disruptive changes brought upon our society by the COVID-19 pandemic, most work activities and service providers had to resort to remote working. This is credited to reduce emissions for transportation, however the role of forced confinement within dwellings, especially if not designed for hosting working stations, deserves to be properly evaluated in terms of both user acceptance and long-term environmental impact. In this work, a dedicated survey campaign is used for investigating the potential pros and cons of remote working. In more detail, logistic regression and generalized linear models are used for capturing the effect of several independent variables on user acceptance of remote working. At a later stage, the main greenhouse gas emissions produced by each participant before and during remote working are assessed. According to the obtained results, the greater the distance between their home and workplace, the higher the acceptance score declared by the survey participants about remote working. Additionally, higher incomes and better-quality lifestyles with larger devotion to leisure activities also provide higher acceptance. Finally, the existence of a comfortable room to be used for work activities plays a crucial role on the declared acceptance. From an environmental point of view, remote working is always sustainable in case of long commuting distances (above 10 km) are avoided on a daily routine. In conclusion, a sensible use of remote working could reduce the environmental impact of any organization employing desk-workers as well as improve their work satisfaction and lifestyle.

The use of Phase Change Material (PCM) for improving building indoor thermal comfort and energy saving has been largely investigated in the literature in recent years, thus confirming PCM’s capability to reduce indoor thermal fluctuation in both summer and winter conditions, according to their melting temperature and operation boundaries. Further to that, the present paper aims at investigating an innovative use of PCM for absorbing heat released by cement during its curing process, which typically contributes to micro-cracking of massive concrete elements, therefore compromising their mechanical performance during their service life. The experiments carried out in this work showed how PCM, even in small quantities (i.e., up to 1% in weight of cement) plays a non-negligible benefit in reducing differential thermal increases between core and surface and therefore mechanical stresses originating from differential thermal expansion, as demonstrated by thermal monitoring of cement-based cubes. Both PCM types analyzed in the study (with melting temperatures at 18 and 25 ∘ C) were properly dispersed in the mix and were shown to be able to reduce the internal temperature of the cement paste by several degrees, i.e., around 5 ∘ C. Additionally, such small amount of PCM produced a reduction of the final density of the composite and an increase of the characteristic compressive strength with respect to the plain recipe.

The need for reducing the environmental impact of the building sector in terms of both energy consumptions and greenhouse gases emissions has led to the development of several types of materials characterized by tailored properties for optimizing surface energy balance of urban surfaces. Among the most acknowledged cool materials, photoluminescent ones are gaining credit not only for their sustainable lighting contribute, but also for their passive cooling potential. The discovery of new phosphors with good afterglow qualities, in terms of intensity and duration, produced promising performances for different applications. In this context, the present chapter investigates the multidisciplinary potential of photoluminescence in energy and environmental strategies, after presenting a general background on the phenomenon itself. The most common techniques for the materials' analysis are also presented, followed by the description of engineering solutions for both indoors and outdoors.