• Energy Research
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This study critically examines the mediating role of employees’ eco-friendly behavior (EFB) and the moderating role of green organizational support (GOS) within the relationship between green human resource management (GHRM) and environmental performance (EP) in Turkey’s hospitality sector. As the global hospitality industry grapples with its significant environmental footprint, this research addresses an acute need for empirically grounded insights into how organizational strategies and employee behaviors can be leveraged to achieve sustainability objectives. The study draws on primary data collected from 346 employees across multiple five-star hotels in Turkey. Data collection was facilitated through structured surveys, and analysis employed confirmatory factor analysis and structural equation modeling. Results provide evidence for EFB’s mediating role and GOS’s moderating effects. Findings underscore the need for comprehensive GHRM strategies synergized with robust GOS systems to foster employee commitment to sustainability goals.

An economic assessment of an innovative solar thermal system called Application to Solar Thermal Energy to Processes (ASTEP) was conducted. It considered its three main subsystems: a novel rotary Fresnel SunDial, Thermal Energy Storage (TES) and Control System. Current Fresnel collectors are unable to provide thermal energy above 150 °C in high-latitude locations. Therefore, the key contribution of this study is the assessment of the economic performance of the ASTEP system used to provide high-temperature process heat up to 400 °C for industries located at low and high latitudes. The ASTEP system is installed at two end-users: Mandrekas (MAND), a dairy factory located in Greece at a latitude of 37.93 N and ArcelorMittal (AMTP), a manufacturer of steel tubes located in Romania at a latitude of 47.1 N. The life cycle costs (LCC), levelised cost of energy (LCOE), energy cost savings, EU carbon cost savings and benefit–cost ratio (BCR) of the ASTEP system were assessed. The results showed that AMTP’s ASTEP system had higher LCC and LCOE than MAND. This can be attributed to the use of two TES tanks and a double-axis solar tracking system for AMTP’s ASTEP system due to its high latitude location, compared to a single TES tank and single-axis solar tracking system used for MAND at low latitude. The total financial savings of the ASTEP system were EUR 249,248 for MAND and EUR 262,931 for AMTP over a period of 30 years. This study demonstrates that the ASTEP system offers financial benefits through its energy and EU carbon cost savings for industries at different latitudes while enhancing their environmental sustainability.

The Digital Grey Divide (DGD) is a phenomenon that refers to the digital inequality existing among the elderly in using digital tools. DGD could generate social exclusion and hinder elderly well-being because today many aspects of life are online. The objective of the research is to compare the urban and rural group to see if a digital divide is present and whether psychological and cognitive well-being can be predictors of usage. The research involved 100 elderly people (belonging to two different areas: one rural and one urban) aged 65 to 90 (M = 72.3; SD = 6.4) with intact cognitive functioning investigated by the MMSE test. A socio-anagraphic module to investigate digital use (DU), a questionnaire on cognitive reserve (CRIq), and a questionnaire investigating well-being (Ben-SSC) were administered. Results showed that the two groups differ in terms of access and use of digital tools (F = 28.34, p < 0.001), with the urban group reporting higher levels of access and use. Moreover, in the urban group, psychological well-being has an inverse relationship with digital, while in the rural group, the relationship between cognitive well-being and use is direct. Therefore, the study aims to highlight how even in developed countries there can be a digital divide (DD) given the risks of exclusion, particularly for the elderly population. For all these reasons, it is necessary to pursue interventions to achieve a higher level of digitalization and sustainable development among the population. Given the importance of this phenomenon, it is necessary to address the issue of DD in various spheres of life: political, social, economic and care.

Sustainable development relies on the circularity in the built environment, which, in turn, includes recycling construction and demolition waste and using recycled materials. However, using fine recycled fractions is challenging, especially considering the requirements for new building applications. Yet, producing more widely applied recycled coarse aggregates usually leads to the simultaneous generation of recycled sand fraction, which contains many fines that pose potential problems. This work presents the direct incorporation of concrete and mixed waste-based recycled sand and recycled fines in masonry mortars, on the one hand, as a complete aggregate replacement and, on the other, only replacing the finest aggregate fraction. Such mortars are assessed based on the fresh and hardened mortar properties and are compared to natural aggregate-containing mortars. In the fresh state, the mortars with recycled fines and recycled sand required more mixing water to produce comparable consistency and workability. In a hardened state, mortars with recycled mixed waste sand and fines have demonstrated increased mechanical strength compared to natural aggregate mortars. In contrast, those containing recycled concrete aggregates and fines were inferior in that regard. This indicates the potential of using recycled mixed waste fractions to improve masonry mortar performance, although both types might be important in enhancing the sustainability of masonry construction.

The building energy performance gap, resulting from a discrepancy between the actual energy use and theoretical calculations, remains a persistent issue in building design. This study examines the energy performance of three multifamily buildings with a collective heating system powered by gas boilers and solar collectors: two that underwent deep renovation and one newly built. An extensive on-site monitoring system provides detailed data on both the heating demand and the final energy use. To ensure comparability, the total energy use of each unit is normalised using the energy signature method. The findings show the large spread of actual energy demands due to a wide variation in user profiles. The majority of dwellings have an actual energy use that is significantly higher than calculated, which is largely attributable to space heating. The gap is further exacerbated by substantial heat losses within the building’s heating system and by limited gains from the solar collectors, indicating discrepancies between design models and operational realities. To bridge this gap, there is a need for rigorous commissioning processes, at least during the initial operation phase start-up and ideally continuously. This can ensure more effective utilisation of renewable energy sources and reduce energy inefficiencies.

Concrete manufacturing and recycling must evolve to meet sustainability and carbon reduction demands. While the focus is often on reusing coarse aggregates, fine fractions are also produced during recycling. This study explores using ground fine fractions (0/2) as a partial cement substitute. The fines were characterized for their mineralogical, chemical, and physical properties, and experiments were conducted on pastes and mortars with 0% to 30% cement substitution, including isothermal calorimetry and strength tests. Two concrete mixes—a reference mix with natural aggregates and CEM I, and a mix with 10% concrete fines replacing CEM I—using recycled sand and coarse aggregates were tested for compressive strength, carbonation, shrinkage, and freeze–thaw resistance. The results indicated that the recycled concrete had a comparable strength to the reference and a slightly reduced durability in freeze–thaw conditions. In terms of shrinkage, recycled concrete with 10% concrete fines had an increased drying shrinkage and a lower autogenous shrinkage due to the water retention capacity of the recycled aggregates.