• Energy Research
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Abstract Concrete is identified in the literature as a suitable material for thermal energy storage applications, with even innovative application potentials such as storage media in concentrating solar power plants. To ensure a suitable heat transfer among concrete components, the binder material of concrete (cement paste) require further research and understanding to this aim. In particular, the thermal stability of cement paste under temperature cycled conditions arises as a research gap. In this study, ordinary Portland and calcium aluminate cement types were selected using a low water-cement ratio. Thermo-mechanical properties were studied before and after 1, 10, and 25 or 50 thermal cycles at 200 °C, 400 °C, 600 °C, and 800 °C. Although ordinary Portland cement paste showed micro-cracking propagation after 25 thermal cycles from ambient temperature to 200 °C and 400 °C, both cement pastes preserved their integrity, being compressive strength higher in ordinary Portland cement. On the contrary, after 25 or 50 thermal cycles at 600 °C and 800 °C, only calcium aluminate cement preserved its integrity, while ordinary Portland cement revealed a fragmentation status. Despite the compressive strength decrease in calcium aluminate paste at 600 °C and 800 °C, as a result of porosity increase, the properties were maintained after 10 thermal cycles. However, thermal conductivity in calcium aluminate paste was reduced nearly 50% after the first cycle at temperatures higher than 200 °C.

In the recent years, some experimental forms of housing (cohousing and social housing) have developed in Italy, which also take on the features of real energy communities. These initiatives have been planned and implemented thanks to the active participation and investments of the people involved in the project. Their primary aim is to implement new form of shared housing, but by adopting renewable generation systems and sharing both energy production and consumption, they are contributing to foster the energy transition process. In this research, we studied the management of the energy resource and the social interactions among the cohousers. Moreover, we analysed the social impacts on the surrounding territory in order to know as they can widespread the clean energy technologies and social innovation processes. To do this, we compared two experiences of collaborative housing: the first one, active since some years in Northern Italy, is a bottom-up initiative set up by the voluntary action of some families and individuals. Its goal is to share common spaces and activities, but also to produce and use renewable energy with a view to economic and environmental sustainability. The second one is a social cohousing, established in Messina (Southern Italy) and implemented by the Fondazione di Comunità di Messina. The project involves people who live in socio-economic difficulties. Through the ESCO Solidarity & Energy, the Fondazione has designed and applied energy systems to allow the tenants to become prosumers and prosumagers.

In our research we identified 45 business model patterns with the potential to support sustainable business design. These patterns were arranged in groups based on commonalities in the sustainability challenges the patterns address. The following 11 groups will be presented in detail in our forthcoming book:  Group 1: Pricing & Revenue Patterns primarily address the revenue model of a business model, i.e. these patterns define how offerings are priced and revenues generated.  Group 2: Financing Patterns address the financing model within a business model, i.e. these patterns define how equity, debt, and operating capital can be acquired.  Group 3: Eco-Design Patterns integrate ecological aspects into key activities and value propositions, i.e. these patterns define how processes and offerings are designed to improve their ecological performance over their entire life cycle.  Group 4: Closing-the-Loop Patterns help integrate the idea of circular material and energy flows into partnerships, key activities, and customer channels, i.e. these patterns offer alternative ways of how materials and energy flow into, out of, and return to a company.  Group 5: Supply Chain Patterns modify the upstream (partners, resources, capabilities) and/or downstream (customers, relationships, channels) components of a business model, i.e. these patterns define how inputs are sourced and target groups are reached.  Group 6: Giving Patterns help donate products or services to target groups in need, i.e. these patterns define how costs are covered and social target groups are reached.  Group 7: Access Provision Patterns create markets for otherwise neglected target groups, involving modified value propositions, channels, revenue, pricing and cost models, i.e. these patterns define how value propositions are designed, delivered, and to whom.  Group 8: Social Mission Patterns integrate social target groups in need, including otherwise neglected groups, either as customers or productive partners, i.e. these patterns define how customers, partners, and employees are defined and integrated.  Group 9: Service & Performance Patterns emphasize the functional and service value of products and offer performance management, i.e. these patterns are special in how value propositions are defined and delivered.  Group 10: Cooperative Patterns integrate a broad range of stakeholders as co-owners and co-managers, i.e. these patterns are special in how partners are defined and how the organization is governed.  Group 11: Community Platform Patterns substitute resource or product ownership with community-based access to resources and products, i.e. these patterns offer alternatives to how value propositions are defined and delivered.

Synopsis Since the late 1800s, anthropogenic activities such as fossil fuel consumption and deforestation have driven up the concentration of atmospheric CO2 around the globe by >45%. Such heightened concentrations of carbon dioxide in the atmosphere are a leading contributor to global climate change, with estimates of a 2–5° increase in global air temperature by the end of the century. While such climatic changes are mostly considered detrimental, a great deal of experimental work has shown that increased atmospheric CO2 will actually increase growth in various plants, which may lead to increased biomass for potential harvesting or CO2 sequestration. However, it is not clear whether this increase in growth or biomass will be beneficial to the plants, as such increases may lead to weaker plant materials. In this review, I examine our current understanding of how elevated atmospheric CO2 caused by anthropogenic effects may influence plant material properties, focusing on potential effects on wood. For the first part of the review, I explore how aspects of wood anatomy and structure influence resistance to bending and breakage. This information is then used to review how changes in CO2 levels may later these aspects of wood anatomy and structure in ways that have mechanical consequences. The major pattern that emerges is that the consequences of elevated CO2 on wood properties are highly dependent on species and environment, with different tree species showing contradictory responses to atmospheric changes. In the end, I describe a couple avenues for future research into better understanding the influence of atmospheric CO2 levels on plant biomaterial mechanics.

Abstract Yeast immobilization in beer fermentation has recently regained attention, due to the expansion of the craft beer market and the diversification of styles and flavors. The aim of this study was to evaluate the physiological differences between immobilized and free yeast cells with a focus on flavor-active compounds formation. Three strains of Saccharomyces spp. (SY025, SY067, SY001) were evaluated in both free and immobilized (using a cellulose-based support, referred as ImoYeast) forms during static batch fermentations of 12 °P malt extract. Immobilized cells showed higher glycerol (SY025, 40%; SY067, 53%; SY001, 19%) and biomass (SY025, 67%; SY067, 78%; SY001, 56%) yields than free cells. Conversely, free cells presented higher ethanol yield (SY025, 9%; SY067, 9%; SY001, 13%). Flavor-active compounds production exhibited significant alterations between immobilized and free cells systems, for all strains tested. Finally, a central composite design with varying initial biomass (X0) and substrate (S0) concentrations was conducted using strain SY025, which can be helpful to modulate the formation of one or more flavor-active compounds. In conclusion, yeast immobilization in the evaluated support resulted in flavor alterations that can be exploited to produce different beer styles.

In recent years, the biomass as a renewable feedstock has been gaining utmost importance in order to meet the global need for fuels and chemicals from sustainability perspectives [1,2]. Principal components of biomass are cellulosic and triglycerides derivatives. The triglyceride part is principally used to obtain biodiesel and liquid alkanes, as alternative fuels [3]. Biomass derived from the lignocellulose part is rich in carbohydrates and furan derivatives, and the presence of oxygen in their structure makes them suitable for further utilization to obtain added-value products. As concern the sustainability of the chemical processes, efforts are being made to turn them into "green" processes, working on the procedures (favorable reagent ratio, catalyst amount and green solvents) and exploiting heterogeneous catalysis. The use of solid catalyst is indeed very favorable from a sustainable point of view, due to its simple separation, regeneration and recycling of the material [4,5]. This implies a high efficiency of the catalysts accompanied by a decrease in the processing cost. This presentation will focus on different types of functionalized silica or titania based materials applied to the biomass exploitation, both to the synthesis of biodiesel and its additives and for the obtainment of added-value products such as GVL, diols or HMF. Biomass can use also for the production of new materials applied in the abatement of aqueous pollutants

Artículos en revistas Este estudio analiza cómo las estrategias de responsabilidad social corporativa ambiental (ECSR) contribuyen a mejorar la innovación entre las pequeñas y medianas empresas (PYMES) mediante el desarrollo de recursos tecnológicos. Probamos nuestras hipótesis durante un período de ocho años utilizando un panel de 2.405 pymes industriales en España. Encontramos empíricamente que ECSR impulsa la construcción de los recursos tecnológicos de las empresas, lo que resulta en una mejora de su esfuerzo tecnológico o I + D y resultados en términos de innovación de productos y procesos. ECSR intensifica la innovación para empresas innovadoras y cataliza el inicio de la innovación para empresas que antes no innovaban, y los efectos resultantes se mantienen en el tiempo. Contribuimos a la literatura analizando los efectos de ECSR en la promoción de la innovación de las empresas más allá de la conocida influencia en la innovación verde. Además, examinamos el área de investigación descuidada de las estrategias ambientales de las PYME. Nuestros hallazgos fortalecen el valor innovador instrumental de ECSR, específicamente para las PYMES. This study analyzes how environmental corporate social responsibility (ECSR) strategies contribute to enhancing innovativeness among small and medium-sized enterprises (SMEs) by developing technological resources. We test our hypotheses over an eight-year period using a panel of 2,405 industrial SMEs in Spain. We empirically find that ECSR drives the building of firms’ technological resources, which results in an enhancement of their technological effort or R&D and outcomes in terms of product and process innovation. ECSR intensifies innovation for innovative firms and catalyzes the inception of innovation for previously non-innovating firms, and the resultant effects are sustained over time. We contribute to the literature by analyzing the effects of ECSR in promoting the innovation of firms beyond the well-known influence on green innovation. Further, we examine the neglected research area of the environmental strategies of SMEs. Our findings strengthen the instrumental innovative value of ECSR, specifically for SMEs. info:eu-repo/semantics/publishedVersion

Abstract The integration of the Photovoltaic (PV) - based Distributed Generation (DG) Systems to the conventional electrical grid is a significant issue to achieve a confidential grid operation. This study presents a novel structure for the suppression of the common-state leakage current for PV-based inverters. It investigates the real-time performance of the inverter for the grid-code compatibility of the PV-based microgrid applications. Many of the topologies have been introduced to suppress leakage currents in grid-based Photovoltaic (PV) inverters, but most of them cannot practically reach more than 95% efficiency. The number of the components, especially the switching semiconductors, including the power switches and power diodes and the current and ripples' level in the topology filter side inductors, are essential criteria for efficiency. The proposed inverter includes six power switches and two power diodes. Since different operational states, only two power components per branch of the inverter are activated a higher efficiency than the conventional H5, H6, and HERIC converters. It presents the THD equal to 1,42 for load-connection states that is considerable. This converter can also generate pure sinusoidal current and voltage waveforms for the reactive loads, especially resistive-inductive load connections that are most common in industrial applications. As a study-case, the implemented inverter was tested under different grid conditions in the laboratory, and a real-time LabVIEW-based monitoring and grid protection system was realized within the research scope. Under/over-frequency protection and under/over voltage protection were performed to provide a reliable microgrid management system for the developed inverter. According to IEEE 929-2000 threshold values for the breakers' reaction operation under the ±10% as the output threshold voltage, the converter's performance is presented. A real-time monitoring and protection system are developed, and the developed LabVIEW analyzer has done the hardware test results. THD and spectrum analysis are also investigated in the real-time domain by the developed inverter test system. In this way, the implemented inverter's grid code compatibility is investigated in real-time, and the experimental results show that the proposed inverter is reliable for PV-based microgrid applications.

This research proposes an innovative solar thermal plant able to generate mechanical power through an optimized system of heliostats with Scheffler-type solar receivers coupled with screw-type steam expanders. Scheffler receivers appear to perform better than parabolic trough collectors due to the high compactness of the focal receiver, which minimizes convective and radiative heat losses even at high vaporization temperatures. At the same time, steam screw expanders are volumetric machines that can be used to produce mechanical power with satisfactory efficiency also by admitting two-phase mixtures and with further advantages compared to steam turbines: low working fluid velocities, low operating pressures, and avoidance of overheating. This study establishes a mathematical model to assess the energetic advantages of the planned solar thermal power system by evaluating the solar-to-electricity efficiency for different off-design working conditions. For this purpose, a numerical model on the Scheffler receiver is initially investigated, thus assessing all the energy losses which affect the heat transfer phase. A thermodynamic model is then developed to evaluate the energy losses and performance of the screw expander under real working conditions. Finally, parametric optimization of the solar energy conversion is performed in a wide range of operating conditions by establishing thermodynamic formulations related to the whole solar electricity generation system. Water condensation pressure and vaporization temperature are so optimized with respect to global energy conversion efficiency which, under the best operating conditions achieved in this research, rises from 10.9% to 14.4% with increasing solar irradiation intensity. Hence, the combined use of screw expanders and Scheffler receivers for solar thermal power system application can be a promising technology with advantages over parabolic dish concentrators. Novelty statement: This research proposes an innovative direct steam solar power plant based on an SRC, with water utilized as both heat transfer and working fluid, equipped with Scheffler solar receivers as a thermal source and screw expanders as work-producing devices. Technical studies and energy assessments of this kind of SEGS at part-load operation do not exist in scientific literature; after reviewing the literature, it was determined that volumetric expanders have been rarely combined with Scheffler receivers for solar thermal power system application. In effect, combined use of screw expanders and Scheffler-type solar concentrator in a direct steam solar power system represents a completely new plant configuration; however, as a promising DSG solar system, at present numerical model of this new sort of SEGS is lacked in literature and the optimum operating conditions have yet to be defined. For this reason, the chief objective of this paper is to define a first parametric optimization of all thermodynamic variables involved to maximize global efficiency of the proposed solar thermal power generation system for ordinary working conditions.