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Buildings are constructed and operated to satisfy human needs and improve quality of life. Good indoor air quality and thermal comfort are prerequisites for human health and well-being. At the same time, these aspects are strictly linked to the buildings’ energy consumption, with a direct impact on energy efficiency global goals and climate changes. Global technical regulations and guidelines aim at increasing the energy performance of buildings, with targets of NZEB and ZEB, both for new and existing buildings. In this context the research was carried out in order to investigate energy saving strategies related to heating systems, combining with indoor comfort analyses. The case study is an existing building, located in Perugia (Italy), which is the main seat of Arpa Umbria. The recent energy crisis has imposed strict measures to contain energy consumption, especially for heating; for this reason, the study aims to identify optimal management of the heating, based on a thermal calibrated model of the building and thermo-hygrometric monitoring. With the model, different management strategies were defined and simulated in order to develop schedules to set switch-on/off systems based on indoor and outdoor weather conditions. The results are presented in an integrated approach, combining the estimated reduction of energy consumption with human well-being.

Environmental issues, especially those related to the over-exploitation of natural resources, are leading towards considering alternative solutions and new approaches, such as the circular economy. Currently, some key elements of the circular economy approach are sustainable procurement of raw materials, improvement of production processes and ecological design, adoption of more sustainable distribution and consumption models, development of secondary raw material markets. This work aims to analyse the use of hemp as a building material, replacing traditional construction materials, but respecting at the same time the thermal, insulating and acoustic characteristics required in the construction of a building. The methodology used was Life Cycle Assessment (LCA), which considered the hemp cultivation phase and the production phase of hemp-lime (“hempcrete”) walls. The hempcrete product was compared with two different solutions: a hemp and lime block, and a traditional perforated brick block with external insulation in polystyrene. In particular, the differences among the products in terms of embodied energy and net CO2 emissions were analysed. Results showed that the hempcrete wall had better environmental performances than the other two solutions.

The Sala del Dottorato (Hall of Graduates) is a magnificent library in the University of Perugia which plays the double role of providing optimal conservation of valuable books and manuscripts while also hosting important events. This double role is closely connected to contrasting indoor microclimatic conditions. This paper presents the results of a multidisciplinary study, begun in 2019, which investigates optimal conditions for the conservation of volumes by monitoring thermo-hygrometric and air quality parameters. The study describes the current conditions of the Hall (in terms of air temperature, relative humidity and concentration of CO2), highlighting critical aspects, defining strategies for their mitigation and control, and outlining future developments. Improvement measures relate to the installation of a permanent monitoring system with alarm settings and data storage, technical interventions on the windows, and the restoration of several volumes. The paper shows the importance of monitoring as an instrument of control in real time and provides guidelines for management to be implemented according to indoor microclimatic conditions. [ABSTRACT FROM AUTHOR]

Surface defects engineered nano‐Cu/TiO2 photocatalysts are synthesized through an easy and cost‐effective microwave‐assisted hydrothermal synthesis, mixing commercial P25 titania (TiO2) and oxalic acid (Ox), followed by 2.0 wt% Cu co‐catalyst (labeled as Cu2.0) loading through in situ photodeposition during reaction. The hydrothermal treatment does not affect the catalyst crystalline structure, morphology, nor the surface area. However, depending on the Ox/TiO2 molar ratio used an influence on the optical properties and on the reactivity of the system is detected. The presence of surface defects leads to intraband states formation between valence band and conduction band of bare titania, inducing an important enhancement in the photoactivity. Thus, Cu2.0/gOx/P25 200 (where g is the weight of Ox and 200 the temperature in Celsius degrees used during the synthesis) have been successfully tested as efficient photocatalysts for hydrogen production through methanol (MeOH) reforming under UV light in a MeOH/ H2O solution (10% v/v) by fluxing the system with N2, showing an increased reactivity compared to the bare Cu2.0/P25 system. [ABSTRACT FROM AUTHOR]

The combination of the ability to absorb most of the solar radiation and simultaneously suppress infrared re-radiation allows selective solar absorbers (SSAs) to maximize solar energy to heat conversion, which is critical to several advanced applications. The intrinsic spectral selective materials are rare in nature and only a few demonstrated complete solar absorption. Typically, intrinsic materials exhibit high performances when integrated into complex multilayered solar absorber systems due to their limited spectral selectivity and solar absorption. In this study, we propose CoSbx (2 < x < 3) as a new exceptionally efficient SSA. Here we demonstrate that the low bandgap nature of CoSbx endows broadband solar absorption (0.96) over the solar spectral range and simultaneous low emissivity (0.18) in the mid-infrared region, resulting in a remarkable intrinsic spectral solar selectivity of 5.3. Under 1 sun illumination, the heat concentrates on the surface of the CoSbx thin film, and an impressive temperature of 101.7 °C is reached, demonstrating the highest value among reported intrinsic SSAs. Furthermore, the CoSbx was tested for solar water evaporation achieving an evaporation rate of 1.4 kg m−2 h−1. This study could expand the use of narrow bandgap semiconductors as efficient intrinsic SSAs with high surface temperatures in solar applications. The efficiency of CoSbx (where 2 < x < 3) as a selective solar absorber is investigated. Here, authors demonstrate that CoSbx endows broadband solar absorption (0.96) and simultaneous low emissivity (0.18), making it a promising material for use in solar energy systems. [ABSTRACT FROM AUTHOR]

The aim to reduce carbon dioxide emissions and to improve buildings energy efficiency has led to develop smart grids to manage electricity and heat. The work deals with the thermal and electric microgrid analysis of the Loccioni Company: the production facility consists of high-energy performance industrial and office buildings, partially powered by produced on-site renewable energy (solar PV, hydropower plants, water ground heat pumps). The challenge of continuous improvement in the use of energy led the company to develop a thermal microgrid for optimal management of the heat produced by a small-scale CHP system (50 kWel/110 kWth). The cogeneration system is based on biomass (pellet) chemical degradation process of gasification. The work discusses preliminary results relating to the first months of the system operation, to highlight the energy benefits and the critical issues. Data are collected by the Company monitoring system and a laboratory feedstock physico-chemical characterization is carried out. The main goal of this paper is to lay the foundations for the development of an energy management system that regulates energy flows between buildings. The development of the thermal microgrid will guarantee not only tangible benefits in terms of energy savings but also an increase in the resilience of the entire building/plant system.

The object of this paper is the “Loccioni Leaf Lab”, an industrial nZEB connected to a thermal and electric smart grid. Having nZEB buildings connected to a smart grid offers the possibility of maximizing the benefits that can be obtained by optimal regulation of the grid itself, providing excellent economic and energy results. The case study, which hosts offices and workers operating on test benches, features high performance envelope, solar photovoltaic systems, groundwater heat pumps and a hightechnology control and monitoring system. In order to analyse HVAC-related energy consumptions, the building was modelled using DesignBuilder and EnergyPlus software. The annual dynamic simulations for the assessment of building thermal-energy performance were carried out using available monitored weather data (2019). The model was validated according to ASHRAE guidelines, comparing the outputs of the software with data collected and stored by Company internal database. In the validation process, mean indoor air temperatures of several zones and heating and cooling energy consumptions were considered as key outputs. The validated model has then been used to suggest optimization strategies and to analyse the results obtained with proposed interventions in terms of energy saving.