El comportamiento energético de una fachada ventilada de juntas abiertas

En este trabajo se muestra un estudio del comportamiento térmico y dinámico de una fachada ventilada de juntas abiertas. Más concretamente, se han realizado medidas experimentales y simulaciones numéricas orientadas a la investigación del funcionamiento de una fachada ventilada de juntas abiertas expuesta a la radiación solar en periodo de verano y de invierno. En el estudio experimental, primeramente, se han obtenido las características globales de funcionamiento de una fachada ventilada de juntas abierta situada en un edificio en la ciudad de Almería. Después, mediante la utilización de sensores de temperatura se han obtenido las distribuciones de las temperaturas en la cara interior del revestimiento exterior (plaquetas cerámicas), en el canal de aire y en la pared interior del cerramiento. Se ha estudiado la validez de los distintos resultados mediante un correspondiente análisis. Las simulaciones numéricas se han llevado a cabo utilizando un programa basado en la solución de las ecuaciones de Navier-Stokes por medio de un algoritmo de volúmenes finitos. La turbulencia se ha simulado por medio de un modelo k-e estándar y como modelo de radiación se ha utilizado un modelo de ordenadas discretas (DO) con el cual se han podido reproducir los efectos de la radiación solar incidente sobre la fachada mediante varios ángulos de incidencia; a esa se ha restado el correspondiente porcentaje debido a la reflectividad del material de las placas (entre 40-60%). Además, se ha tenido en cuenta el efecto de la radiación reflejada desde el suelo, incluida la radiación incidente en el nivel del suelo. Se han realizado simulaciones bidimensionales estacionarias y además se ha generado un modelo tridimensional. La comparación de los resultados indica una gran aproximación de las simulaciones numéricas a la definición de los distintos fenómenos globales del funcionamiento de una fachada ventilada de juntas abiertas. En concreto, el modelo tridimensional muestra resultados muy próximos a los experimentos. El modelo bidimensional también aproxima satisfactoriamente dichas curvas a pesar de sus inherentes limitaciones. Se han obtenido las distribuciones de temperaturas en revestimiento exterior, cámara de aire y pared interior tanto numérica como experimentalmente. Los modelos numéricos reflejan correctamente los fenómenos y tendencias observados, aunque no se adaptan a los valores cuantitativos medidos experimentalmente. A partir de los trabajos numérico y experimental realizados se ha llegado a una comprensión más clara sobre cómo es el funcionamiento de una fachada ventilada de juntas abiertas, así como implementar técnicas de simulaciones para la caracterización de este tipo de cerramiento. También se ha llegado a conclusiones interesantes sobre el efecto que tiene la separación del suelo y la influencia de la radiación sobre el tipo de material del revestimiento. Finalmente, se plantean posibles ampliaciones del trabajo abordables según se vaya aumentando la potencia de cálculo, así como el desarrollo de nuevas metodologías de medida. Se prevé que en un futuro próximo las modelizaciones numéricas hayan llegado a un grado de madurez tal que se conviertan en una herramienta imprescindible tanto para el diseño como para el análisis del comportamiento bioclimatico de una fachada ventilada de juntas abierta

Challenges for a Positive Energy District Framework

This paper presents the key technical and non-technical challenges for the development of a Positive Energy District (PED) framework. It draws on literature, expert reviews and surveys. Initial findings reveal that there are seven primary interacting factors that cascade from the strategic to the specific, or from international ambitions to contextual opportunities (and vice versa). Each is a necessary and integral factor that underpins successful development of PEDs.COST Action CA19126 – Positive Energy Districts European Network (PED-EU-NET

How Can Scientific Literature Support Decision-Making in the Renovation of Historic Buildings?:An Evidence-Based Approach for Improving the Performance of Walls

Buildings of heritage significance due to their historical, architectural, or cultural value, here called historic buildings, constitute a large proportion of the building stock in many countries around the world. Improving the performance of such buildings is necessary to lower the carbon emissions of the stock, which generates around 40% of the overall emissions worldwide. In historic buildings, it is estimated that heat loss through external walls contributes significantly to the overall energy consumption, and is associated with poor thermal comfort and indoor air quality. Measures to improve the performance of walls of historic buildings require a balance between energy performance, indoor environmental quality, heritage significance, and technical compatibility. Appropriate wall measures are available, but the correct selection and implementation require an integrated process throughout assessment (planning), design, construction, and use. Despite the available knowledge, decision-makers often have limited access to robust information on tested retrofit measures, hindering the implementation of deep renovation. This paper provides an evidence-based approach on the steps required during assessment, design, and construction, and after retrofitting through a literature review. Moreover, it provides a review of possible measures for wall retrofit within the deep renovation of historic buildings, including their advantages and disadvantages and the required considerations based on context

Positive Energy Districts: Identifying Challenges and Interdependencies

Positive Energy Districts (PED) are areas within cities that generate more renewable energy than they consume, contributing to cities’ energy system transformation toward carbon neutrality. Since PED is a novel concept, the implementation is very challenging. Within the European Cooperation in Science and Technology (COST) Action, which offers an open space for collaboration among scientists across Europe (and beyond), this paper asks what the needs for supporting the implementation of PEDs are. To answer this, it draws on Delphi process (expert reviews) as the main method alongside the literature review and also uses surveys as supplementary methods to identify the main challenges for developing PEDs. Initial findings reveal seven interacting topics that later were ranked as highest to the lowest as the following: governance, incentive, social, process, market, technology and context. These are interrelated and interdependent, implying that none can be considered in isolation of the others and cannot be left out in order to ensure the successful development of PEDs. The resources that are needed to address these challenges are a common need for systematic understanding of the processes behind them, as well as cross-disciplinary models and protocols to manage the complexity of developing PEDs. The results can be the basis for devising the conceptual framework on the development of new PED guides and tools

Closing Water Cycles in the Built Environment through Nature-Based Solutions: The Contribution of Vertical Greening Systems and Green Roofs

Water in the city is typically exploited in a linear process, in which most of it is polluted, treated, and discharged; during this process, valuable nutrients are lost in the treatment process instead of being cycled back and used in urban agriculture or green space. The purpose of this paper is to advance a new paradigm to close water cycles in cities via the implementation of naturebased solutions units (NBS_u), with a particular focus on building greening elements, such as green roofs (GRs) and vertical greening systems (VGS). The hypothesis is that such “circular systems” can provide substantial ecosystem services and minimize environmental degradation. Our method is twofold: we first examine these systems from a life-cycle point of view, assessing not only the inputs of conventional and alternative materials, but the ongoing input of water that is required for irrigation. Secondly, the evapotranspiration performance of VGS in Copenhagen, Berlin, Lisbon, Rome, Istanbul, and Tel Aviv, cities with different climatic, architectural, and sociocultural contexts have been simulated using a verticalized ET0 approach, assessing rainwater runoff and greywater as irrigation resources. The water cycling performance of VGS in the mentioned cities would be sufficient at recycling 44% (Lisbon) to 100% (Berlin, Istanbul) of all accruing rainwater roof–runoff, if water shortages in dry months are bridged by greywater. Then, 27–53% of the greywater accruing in a building could be managed on its greened surface. In conclusion, we address the gaps in the current knowledge and policies identified in the different stages of analyses, such as the lack of comprehensive life cycle assessment studies that quantify the complete “water footprint” of building greening systems.info:eu-repo/semantics/publishedVersio

NOTCH and Graft-Versus-Host Disease

In allogeneic hematopoietic stem cell transplantation, which is the major curative therapy for hematological malignancies, T cells play a key role in the development of graft-versus-host disease (GvHD). NOTCH pathway is a conserved signal transduction system that regulates T cell development and differentiation. The present review analyses the role of the NOTCH signaling as a new regulator of acute GvHD. NOTCH signaling could also represent a new therapeutic target for GvHD

Towards Climate Neutrality: Progressing Key Actions for Positive Energy Districts Implementation

Positive Energy Districts (PEDs) represent an emerging urban transition paradigm, an advanced framework to effectively attain decarbonization targets, as well as a holistic approach to foster more resilient and livable cities. However, imple-menting PEDs is challenging, demanding substantial planning, design, and opera-tions changes. Mainstreaming PEDs calls for innovative legal, institutional, business, and organizational frameworks, as well as an active involvement of the main actors (i.e., cities, municipalities, communities, investors, industry players, and service providers), to co-design and jointly progress ambitious agendas, multiscale plans, flexible instruments, and adaptive structures. Benefitting from the authors’ coopera-tion within the Horizon 2020 project, Cooperation in Science and Technology COST Action ‘Positive Energy Districts European Network’ (PED-EU-NET in PED-EU-NET | COST ACTION CA19126, 2020), the proposed contribution addresses relevant issues and opportunities characterizing the development of PEDs in Europe, relating attention to effective implementation, context-specificity, replicability, and upscaling

Positive Energy District e azioni di Deep Renovation per andare oltre gli obiettivi UE 2025. Positive Energy Districts and Deep Renovation actions to move beyond the 2025 EU Targets

Starting from selected results of the COST ACTION PED-EU-NET and IEA EBC Annex 83 PEDs, the article presents an overview of the European projects that, in recent years, have made it possible to evolve from the nZEB concept (applied to deep renovation interventions) toward the Positive Energy District model, redefining the spatial, functional, organizational, technological, and environmental aspects of the inter-scalar relationship between housing, building, and settlement. The ambition is to positively affect the ongoing change, developing tools for knowledge and validation of current experiences, generating new shared values of an ecological-environmental matrix, and promoting quality of life, inclusion, and social sustainability