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[EN] The objective of this article is to compare the behaviour of the most representative domestic hot water systems (DHW) in single-family buildings. The study evaluates the energy consumption, equivalent CO2 emissions and cost for each system over a 15-year life period. This analysis is carried out in four cli- matic zones across Europe to observe the influence of climatic conditions on the results. The four climatic zones are located in the cities of Athens, Madrid, London and Berlin. The analysed systems are: a) natural gas-fired instantaneous water heaters, b) electric storage water heater, c) solar thermal system with gas- fired instantaneous, d) solar thermal system with electric storage water heater, e) air-source heat pump, f) photovoltaic system with electric storage water heater, and g) photovoltaic system with air-source heat pump. This range of technologies covers the most likely solutions to be implemented across domestic buildings in Europe.The heat pump system (HPWH) with PV considering self-consumption shows the lowest environmen- tal impact in all zones, but is not an attractive investment in the coldest zones due to lower natural gas prices. Thermal solar systems have a high purchase and maintenance costs which do not compensate their energy savings. The PV HPWH system has a greater reduction of emissions and a lower cost than HPWH across a 15-year life. The gas boiler system has the lowest cost in a 15-year period in the coldest areas, despite having a greater environmental impact than the heat pump.(c) 2023 Elsevier B.V. All rights reserved.

Thermoacoustic technology emerges as a sustainable and low-carbon method for energy conversion, leveraging environmentally friendly working mediums and independence from electricity. This study presents the development of a multimode heat-driven thermoacoustic system designed to utilize medium/low-grade heat sources for room-temperature cooling and heating. We constructed both a simulation model and an experimental prototype for a single-unit direct-coupled thermoacoustic system, exploring its performance in heating-only, cooling-only, and hybrid heating and cooling modes. Internal characteristic analysis including an examination of internal exergy loss and a distribution analysis of key parameters was first conducted in the hybrid cooling and heating mode. The results indicated a positive-focused traveling-wave-dominant acoustic field within the thermoacoustic core unit, enhancing energy conversion efficiency. The output system performance was subsequently tested under different working conditions in the heating-only and cooling-only modes. A maximum output heating power of 2.3 kW and a maximum COPh of 1.41 were observed in the heating-only mode. Meanwhile, a cooling power of 748 W and a COPc of 0.4 were obtained in the typical cooling condition at 7 °C when operating in cooling-only mode. These findings underscore the promising potential of thermoacoustic systems for efficiently utilizing medium/low-grade heat sources for cooling and/or heating applications in the future.

Environmental tax reform (ETR), a shift from labour to carbon taxes, has been mostly modelled using general equilibrium (GE) analysis. Since a low-carbon transition will require deep transformations, one will also have to address out-of-equilibrium dynamics and increased agent heterogeneity. Unlike GE models, agent-based models (ABMs) are well equipped to deal with this. We therefore replicate a recent GE model for ETR using an agent-based approach. This process, known as "agentization", allows assessing similarities as well as differences in policy impacts between the two modelling approaches, in turn providing a test of the robustness of the GE results. We find that the agent-based model is able to replicate many results of the general equilibrium analysis, while revealing strengths and weaknesses of both model types. We discuss concrete implementation steps and difficulties experienced in the GE-ABM translation process. We illustrate the potential of ABM by extending the model in several directions. We show that heterogeneous subsistence consumption can increase the space for combining a double dividend with an equity goal, and that overall macro-economic results can conceal important distributional impacts when green preferences and labour supply elasticities vary.

In industrialized countries, large amounts of mineral wastes are produced. They are re-used in various ways, particularly in road and earth constructions, substituting primary resources such as gravel. However, they may also contain pollutants, such as heavy metals, which may be leached to the groundwater. The toxic impacts of these emissions are so far often neglected within Life Cycle Assessments (LCA) of products or waste treatment services and thus, potentially large environmental impacts are currently missed. This study aims at closing this gap by assessing the ecotoxic impacts of heavy metal leaching from industrial mineral wastes in road and earth constructions. The flows of metals such as Sb, As, Pb, Cd, Cr, Cu, Mo, Ni, V and Zn originating from three typical constructions to the environment are quantified, their fate in the environment is assessed and potential ecotoxic effects evaluated. For our reference country, Germany, the industrial wastes that are applied as Granular Secondary Construction Material (GSCM) carry more than 45,000 t of diverse heavy metals per year. Depending on the material quality and construction type applied, up to 150 t of heavy metals may leach to the environment within the first 100 years after construction. Heavy metal retardation in subsoil can potentially reduce the fate to groundwater by up to 100%. One major challenge of integrating leaching from constructions into macro-scale LCA frameworks is the high variability in micro-scale technical and geographical factors, such as material qualities, construction types and soil types. In our work, we consider a broad range of parameter values in the modeling of leaching and fate. This allows distinguishing between the impacts of various road constructions, as well as sites with different soil properties. The findings of this study promote the quantitative consideration of environmental impacts of long-term leaching in Life Cycle Assessment, complementing site-specific risk assessment, for the design of waste management strategies, particularly in the construction sector.

Integrating environmental, social and governance (ESG) variables into the assessment of a mining project is essential to ensure the short and long term acceptance by the various stakeholders involved and the lack of doing so can put the sustainability of a project at risk. Thus, a holistic approach has been proposed which combines profitability and sustainability analysis with social and environmental considerations for any decisions made on processing operation selection or mine expansion. The potential economic implications of these factors would be used for determining the operational strategy. This study is based on an actual quarry case study and statistical data taken from Spain. Quantitative variables related to ESG aspects have been integrated into a block model, and optimisations were performed based on different plant types and waste disposal strategies. Results demonstrate a strong interdependence between profitability and sustainability. It is observed that strategies related to operating costs impact the environmental and social impacts. A green index is also incorporated to evaluate and compare the different scenarios, determining that the most relevant strategies in adding value to mining projects include investment in new technologies, environmental solutions, and economic and social benefits. Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura Objectius de Desenvolupament Sostenible::8 - Treball Decent i Creixement Econòmic Objectius de Desenvolupament Sostenible::12 - Producció i Consum Responsables Peer Reviewed

Organic solar cells utilize an energy-level offset to generate free charge carriers. Although a very small energy-level offset increases the open-circuit voltage, it remains unclear how exactly charge generation is affected. Here we investigate organic solar cell blends with highest occupied molecular orbital energy-level offsets (∆EHOMO) between the donor and acceptor that range from 0 to 300 meV. We demonstrate that exciton quenching at a negligible ∆EHOMO takes place on timescales that approach the exciton lifetime of the pristine materials, which drastically limits the external quantum efficiency. We quantitatively describe this finding via the Boltzmann stationary-state equilibrium between charge-transfer states and excitons and further reveal a long exciton lifetime to be decisive in maintaining an efficient charge generation at a negligible ∆EHOMO. Moreover, the Boltzmann equilibrium quantitatively describes the major reduction in non-radiative voltage losses at a very small ∆EHOMO. Ultimately, highly luminescent near-infrared emitters with very long exciton lifetimes are suggested to enable highly efficient organic solar cells. Donor–acceptor systems with low energy-level offset enable high power efficiency in organic solar cells yet it is unclear what drives charge generation. Classen et al. show that long exciton lifetimes enable efficient exciton splitting and thus generation of free charges while also suppressing voltage losses.

Resumen: En este Trabajo de Final de Grado se aborda, como principal objetivo la reducción del consumo energético, en una bodega construida en el año 1965 con posteriores modificaciones para adaptarse a las demandas de la producción, en la actualidad tiene capacidad para procesa un máximo de 10 millones de kilos de uva por vendimia. Una de las modificaciones fue el cambio de ubicación de la zona de recepción del mosto, pasando de la cota más alta a la parte más baja de la finca, de unos depósitos de cemento a los de acero inoxidable i de estar ubicados en el interior de la bodega a la intemperie. Como se ha apuntado anteriormente, el principal objetivo de este proyecto es la reducción del consumo energético y concretamente de la zona de recepción, para tal fin se construirá un cofre aislante con las siguientes medidas 35 x 16 x 14 m, albergando en su interior los depósitos y el intercambiador de calor, ejecutándose la obra con dichos elementos inamovibles. Se han realizado los cálculos pertinentes para el dimensionado de la estructura metálica del cofre, de los cabales y dimensiones de los nuevos circuitos de refrigeración, calculando la potencia frigorífica necesaria para mantener la temperatura deseada, con una entrada máxima diaria de 200 tn de uva por día. Los cerramientos se realizarán con paneles aislantes que permitan mantener la temperatura del mosto refrigerado inicialmente hasta su clarificación y trasiego. Se ha calculado un presupuesto de ejecución de obra por contrato y se han elaborado los planos correspondientes. Así pues el proyecto consta de los siguientes documentos: Documento N.º 1 Memoria y 9 Anejos Documento N.º 2 Planos Documento N.º 4 Presupuesto detallado Como conclusión, podemos afirmar que con este proyecto se espera una reducción del 55% en el consumo energético de la zona de Recepción del mosto, mejoraría el rendimiento, tanto energético como en eficiencia con la automatización de las instalaciones entre la zona de Recepción y el Lagar. Abstract: This Final Degree Work addresses the reduction of energy consumption, mainly electricity, of a winery built in 1965, with subsequent modifications adapting to production circumstances, with the capacity to process 10 million kilos of grapes. One of the modifications was the change in location of the must reception area, moving from the highest to the lowest level of the farm, from cement tanks to stainless steel tanks and to be located inside the cellar in the open air. The objective of the project is the reduction of energy consumption in the must reception area, through the construction of an insulating box of 35 x 16 x 14 m, closing the six tanks and the tubular heat exchanger inside. the work being carried out with said immovable elements inside. The necessary calculations have been made for the dimensioning of the metal structure of the chest, the flow rates and the dimensions of the new refrigeration circuits, as well as the refrigeration power necessary to maintain them at the desired temperature, with a daily input of 200 t of grape The enclosures will be made with insulating panels that allow the temperature of the initially cooled must to be maintained until its clarification by gravity. A contract execution budget has been calculated and the corresponding plans have been drawn up. So, the project consists of the following documents: Document Nº1: Memory and 9 chapters. Document No. 2: 19 plans Document Nº4: Detailed budget. As a conclusion we will say that this project is expected to reduce energy consumption in the reception area by 55% and we can affirm that the performance, both energy and efficiency, would improve if the facilities between the Reception area and the Presses. Resum: En aquest treball de Final de Grau s'aborda la reducció del consum energètic d'un celler construït l'any 1965, amb posteriors modificacions per adaptar-se a les circumstancies de la producció, amb capacitat per processar 10 milions de quilos de raïm . Una d'elles va ser el canvi d'ubicació de la zona de recepció del most, passant de la cota mes alta a la part mes baixa de la finca, d'uns dipòsits de ciment a uns d'acer inoxidable i d'estar en el interior del celler al intempèrie. L'objectiu del projecte serà doncs, la reducció del consum energètic de la zona de recepció del most, mitjançant la construcció d'un cofre aïllant de 35 x 16 x 14 m, tancant en el seu interior els dipòsits i l'intercanviador de calor que romandran en el seu lloc mentre s'executi el projecte. S'han realitzat els càlculs necessaris per dimensionar l'estructura metàl·lica del cofre, dels cabals i dimensions dels nous circuits de refrigeració i de la potencia frigorífica necessària per mantenir-los, amb una entrada màxima diària de 200 tn de raïm per dia. Els tancaments es realitzaran amb panells aïllants que permetin mantenir la temperatura del most refredat inicialment, fins al seu desfangat estàtic. S'ha calculat un pressupost d'execució d'obra per contracta i s'han elaborat els plànols corresponents. Així doncs, el projecte consta del: Document Nº 1: Memòria i 9 Annexes. Document Nº 2: 19 plànols Document Nº 4: Pressupost detallat Com a conclusió direm que d'aquest projecte s'espera una reducció del 55% en el consum energètic a la zona de recepció del most i que es milloraria el rendiment, tant energètic com en eficiència amb l'automatització de les instal·lacions entre la Recepció i el Lagar. Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura Objectius de Desenvolupament Sostenible::12 - Producció i Consum Responsables