Optimización en la operación y el diseño de plantas de microcogeneración para edificios de viviendas

390 p.En la actualidad, el sector de la edificación es responsable del 17% del consumo de energía final en España, siendo aproximadamente un 60% debido a la demanda de calefacción y agua caliente sanitaria. La creciente preocupación por reducir este consumo y el impacto ambiental que el mismo implica, han dado lugar a diversas modificaciones del marco normativo enfocadas a una mayor eficiencia energética en los edificios y al el empleo de tecnologías de origen renovable o de alta eficiencia. No obstante, no se dispone de una metodología genérica que permita seleccionar la tecnología o combinación de tecnologías económicamente viable que sea a su vez respetuosa con el Medio Ambiente.Esta tesis presenta una metodología basada en programación matemática lineal que permite seleccionar, dimensionar y establecer el modo de funcionamiento de la hibridación de tecnologías óptima, de acuerdo a criterios económicos y/o medioambientales. Esta misma metodología se aplica a instalaciones de microcogeneración con el fin de determinar el dimensionamiento óptimo y la integración del sistema de almacenamiento térmico que garantiza un mejor aprovechamiento de la energía térmica.A partir de los fundamentos de la Termoeconomía, se ha realizado un estudio comparativo entre los diferentes métodos de asignación de costes, con el objetivo de establecer las ventajas e inconvenientes de cada uno de ellos y acotar su campo de aplicación.Finalmente, se realiza una optimización de la estrategia de control de una instalación real de microcogeneración mediante algoritmos genéticos, contrastando los resultados obtenidos con los obtenidos en la instalación experimental del Laboratorio de Control de Calidad del Gobierno Vasco

Optimización en la operación y el diseño de plantas de microcogeneración para edificios de viviendas

390 p.En la actualidad, el sector de la edificación es responsable del 17% del consumo de energía final en España, siendo aproximadamente un 60% debido a la demanda de calefacción y agua caliente sanitaria. La creciente preocupación por reducir este consumo y el impacto ambiental que el mismo implica, han dado lugar a diversas modificaciones del marco normativo enfocadas a una mayor eficiencia energética en los edificios y al el empleo de tecnologías de origen renovable o de alta eficiencia. No obstante, no se dispone de una metodología genérica que permita seleccionar la tecnología o combinación de tecnologías económicamente viable que sea a su vez respetuosa con el Medio Ambiente.Esta tesis presenta una metodología basada en programación matemática lineal que permite seleccionar, dimensionar y establecer el modo de funcionamiento de la hibridación de tecnologías óptima, de acuerdo a criterios económicos y/o medioambientales. Esta misma metodología se aplica a instalaciones de microcogeneración con el fin de determinar el dimensionamiento óptimo y la integración del sistema de almacenamiento térmico que garantiza un mejor aprovechamiento de la energía térmica.A partir de los fundamentos de la Termoeconomía, se ha realizado un estudio comparativo entre los diferentes métodos de asignación de costes, con el objetivo de establecer las ventajas e inconvenientes de cada uno de ellos y acotar su campo de aplicación.Finalmente, se realiza una optimización de la estrategia de control de una instalación real de microcogeneración mediante algoritmos genéticos, contrastando los resultados obtenidos con los obtenidos en la instalación experimental del Laboratorio de Control de Calidad del Gobierno Vasco

Methodology for integrated modelling and impact assessment of city energy system scenarios

Cities are ought to play a key role in the energy transition to a low carbon society as they concentrate more than half of the world's population and are responsible for about 67% primary energy consumption and around 70% of the energy-related CO2 emissions. To achieve the agreed climate targets, efficient urban planning is a must. Tools and methods have risen to model different aspects of the energy performance of urban areas. Nevertheless, addressing the complexity of a city energy system is a great challenge and new integrated tools and methods are still needed. This paper presents a methodology for integrated city energy modelling and assessment, from the characterization of the city's current energy performance to the development and assessment of future scenarios. Energy characterization is based on the combination of bottom-up approaches with top-down data to establish the city's energy baseline. This baseline integrates bottom-up results from a GIS based model which is used to characterize the city's building stock energy performance, while available information on the vehicle stock is used to model the mobility sector. Scenarios are developed from this baseline and assessed through a multi-criteria impact assessment model. A simplified case study is carried out for the city of Valencia (Spain) to demonstrate the suggested methodology, and results are shown for three different scenarios: one focused on the building sector, one on transport, and one combining measures in both sectors. The transport-focused scenario demonstrates to be the most favourable in terms of energy savings and emissions reductions. The application of the proposed method is intended to support the development of strategies and plans for energy transition at city level. The main challenges for its application in cities are data availability at urban level, the uncertainty related to modelling the transport sector, and the unavailability of adapted I/O tables at city scale to assess socioeconomic impacts

Defining the cooling and heating solar efficiency of a building component skin: application to a modular living wall

[EN] The thermal evaluation of building components composed of a base wall with a solar passive skin solution, such as a vertical/roof greenery system, ventilated facade, reflective painting, etc., is usually performed as a whole. In this research, it has been proven that, independently of the base wall thermal inertia and insulation level, the temperature of the outermost surface layer of any building component during sunny hours is mainly dependent on the ambient air temperature and relative humidity, the incident global solar radiation and the building skin behaviour. The latter assumption has been proven on the south wall of a reference building simulated with TRNSYS. The south wall properties have been varied and the building has been subjected to different climates. The assumption's validity has been checked for twelve south wall cases: a combination of 2 thermal transmittance, 2 thermal inertia and 3 climates. Each case has been simulated for a whole year. Based on this finding and the local ambient conditions for sunny hours, the hypothetical achievable maximum and minimum temperatures for the outermost surface layer have been defined. Then, based on the outermost surface temperature experimental measurements, the cooling and heating solar efficiencies valid for any skin solution have been defined. Furthermore, the developed methodology has been applied to a vertical living wall tested for a whole year under the accuracy and quality procedure of the PASLINK method. In this way, the cooling and heating solar efficiencies were experimentally determined for this skin solution for both, the hot cold seasons. The study has shown that the cooling efficiency during the hot season is 90.8%. As expected, even during sunny summer hours, the presence of water positively affects the performance of the facade, as it brings the base wall external surface temperature close to the ambient wet bulb temperature, therefore reducing the cooling load of the building. For the cold season, the cooling efficiency was similar, at 90.3%, which means a heating efficiency of 9.7%. Again, even for sunny winter hours, the values of the external surface temperature tend towards the ambient air wet bulb temperature, resulting in an increase in the heating demand. These experimental efficiency values allow the heating or cooling behaviour of different skin solutions to be comparable with a single number that is independent of the base wall composition. In addition, independently of the base wall composition, once the experimental efficiency value of a given skin solution is known, it allows (during sunny hours) the base wall outermost surface temperature to be calculated with precision. The latter makes it possible to increase the accuracy of the estimation of the heating and cooling demands of such methods as the degree-day method.This work was supported by the Spanish Ministry of Science, Innovation and Universities and the European Regional Development Fund (grant number RTI2018-096296-B-C22) through the MONITHERM project 'Investigation of monitoring techniques of occupied buildings for their thermal characterization and methodology to identify their key performance indicators', project reference: RTI2018-096296-B-C22 (MCIU/AEI/FEDER, UE). Open Access funding provided by University of Basque Country

Thermal characterization of a modular living wall for improved energy performance in buildings

Vertical vegetation systems are an innovative passive method for decreasing the thermal energy demand of buildings while increasing the quality of urban life. The main objective of this work is to calculate the effectiveness of vegetation in reducing thermal loads analytically. For this purpose, the thermal energy performance of the modular living wall was compared with a traditional double façade construction system to evaluate the influence of vegetation using Stochastic Differential Equations models. The research was carried out experimentally using a real-scale PASLINK test cell. The thermal behaviour of a double leaf bare wall and the same double leaf wall converted into a modular living wall were calculated for different summertime and wintertime periods. In both studied cases, the temperature of the exterior surface of the bare wall is taken at the same place regardless of whether or not there is greenery system in the energy balance. With this simplification, the effect of the modular living wall can be identified within the estimated coefficients. The thermal resistance of the conventional double façade increased 0.74 (m2 K)/W over the non-greened wall, which represents a weighted increase of 49%. Additionally, the experimental results showed that the evapotraspiration processes that take place in the living wall lead to an increase in the combined convection-radiation coefficient, which reduces the overheating of the façade. Moreover, the effective solar absorptivity value of the outermost surface of the bare wall has been reduced an 85% thanks to the living wall, which confirms the high capacity of the living wall to reduce solar heat gains.This publication is part of the R+D+i project PID2021-126739OB-C22, financed by MCIN/AEI/10.13039/501100011033/ and “ERDF A way of making Europe”. This project has been made possible thanks to the agreement between the Basque Government and the University of the Basque Country UPV/EHU through of the ENEDI research group for the management and development of the Thermal Area of the Buildings Quality Control Laboratory of the Basque Government (ATLCCE). Open Access funding provided by University of Basque Country

Modelado termodinámico de sistemas eutécticos sólido-líquido para el estudio de nuevos materiales de cambio de fase

Los sistemas de almacenamiento térmico latente se basan en el empleo de los llamados materiales de cambio de fase (PCMs). Éstos últimos almacenan energía mediante el cambio de fase sólido-líquido y son capaces de ofrecer densidades energéticas entre 5 y 14 veces más elevadas que los materiales para almacenamiento de calor sensible. Estas características hacen de los PCMs materiales muy interesantes respecto a los habitualmente empleados para almacenamiento térmico. Una de las soluciones que se ha venido investigando ampliamente para encontrar mejores PCMs es el desarrollo de mezclas eutécticas de materiales. Mediante el uso de mezclas eutécticos es posible la obtención de nuevos PCMs con temperaturas de fusión ajustables a la aplicación deseada. Sin embargo, la mayoría de los estudios realizados hasta la fecha se han basado en trabajos experimentales de prueba y error. Dicha metodología resulta difícil y costosa, sobre todo si no se posee conocimiento previo en la materia, o experiencia con materiales similares a los que se pretenden estudiar. Es conveniente y adecuado disponer de valores que sirvan como estimación inicial. En base a ello, el presente trabajo se basa en el modelado termodinámico de sistemas eutécticos binarios, con el fin de evaluar y comprender mejor aquellos aspectos prácticos de interés para el desarrollo de nuevos PCMs. Se realizó un estudio paramétrico básico para comprender el efecto que las propiedades de los compuestos originales de la mezcla tienen en el comportamiento de la misma. Las variables a estudio fueron la entalpía de cambio de fase, el peso molecular y la temperatura de cambio de fase de los compuestos puros. En relación a la influencia de la entalpía de fusión, se observó que a mayor entalpía de cambio de fase, menor es la pendiente de la línea de liquidus obtenida. El mismo efecto se apreció en base al peso molecular: cuanto mayor es la masa del compuesto, menor pendiente alcanza la línea de liquidus. Por último, el efecto de la temperatura de cambio de fase fue el siguiente: a menor temperatura de cambio de fase, mas baja es la temperatura eutéctica resultante. Sin embargo, la influencia de la temperatura de fusión en la pendiente de la línea de liquidus es notablemente menor. De los resultados se deduce que, si se parte de un compuesto de elevada entalpía de cambio de fase, a menos que tenga un peso molecular bajo, su línea de liquidus tenderá a ser muy plana. Ello hace que, si pretendemos unirlo con un material de entalpía también alta (para que el compuesto resultante no pierda densidad energética), entonces no conseguiremos una depresión apreciable en la temperatura de fusión del compuesto eutéctico. Lo más conveniente, en todo caso, sería juntarlo con un compuesto con el peso molecular más bajo posible. El método empleado se puede usar como punto de partida en potenciales investigaciones experimentales, con el consiguiente ahorro de esfuerzo y tiempo en el trabajo a realizar.El presente trabajo forma parte del proyecto MicroTES ENE2012-38633, del Ministerio de Economía y Competitividad Español, que cuenta con fondos FEDER. El autor Gonzalo Diarce quiere agradecer la financiación recibida a través del programa Predoc de Formación de Personal Investigador del Gobierno Vasco (convocatoria 2012). Se agradece también el apoyo del Laboratorio de Control de Calidad en la Edificación del Gobierno Vasco. La línea de investigación aquí presentada se coordina además a nivel internacional desde la Task 42/ 29 de la IEA

Prácticas de laboratorio para la determinación experimental del coeficiente de convección

superficies se ha diseñado un equipo para la determinación experimental del coeficiente de convección sobre una placa plana. Constructivamente hablando el equipo está formado por una lámina calefactora colocada sobre la cara superior de una placa de madera. Al conectar la lámina calefactora a la red, se consigue una temperatura superficial superior a la de la cara inferior de la placa de madera, a la del ambiente y a la de las superficies que le rodean. De esta manera se logra que exista un intercambio de calor por conducción a través de la placa, por convección con el aire y por radiación con las superficies circundantes. Los objetivos de la práctica son varios. Por un lado, se busca que el alumnado aplique el balance de energía e identifique los diferentes mecanismos de transmisión de calor que intervienen. Por otro lado, a partir de la medida de diversas temperaturas durante la práctica, el alumnado debe calcular el coeficiente de convección que tiene lugar en esas condiciones. Además, el alumnado debe resolver el intercambio de calor por convección como si fuese un problema de clase, usando las correlaciones de convección existentes en la bibliografía relativa a transferencia de calor. Por último se le pide que calcule la diferencia entre ambos coeficientes de convección de manera porcentual. Una ventaja añadida del equipo es que puede ser igualmente utilizado para la realización de prácticas relativas al mecanismo de radiación

Social organisational LCA for the academic activity of the University of the Basque Country UPV/EHU

Purpose This article aims to estimate the social footprint of a higher education institution (HEI) and its potential contribution to Sustainable Development Goals (SDGs) under life cycle assessment (LCA) perspective. The social organisational life cycle assessment (SO-LCA) of the academic activity of the University of the Basque Country (UPV/EHU), in northern Spain, has been performed, in order to estimate its social impacts. Method The assessment has been run using openLCA software and supported on the PSILCA-based Soca add-on for the Ecoinvent v3.3 database, covering 53 social indicators for almost 15,000 industrial sectors and goods in 189 countries. Results and discussion The analysis undertaken reflects social impacts and associated risk levels for four stakeholders: Workers, Local Community, Society, and Value Chain Actors. Labour activity in the UPV/EHU is the sub-process with the greatest social impact, followed by processes related to transport, energy, materials, and waste management. Among the socio-economic context which supports the academic activity of the UPV/EHU (indirect impacts), the existence of traces of child labour and illiteracy outside the Basque Country stands out. Further analysis would be required in order to more accurately determine the geographical location of such impacts, and also to better tackle the concept of social debt. Conclusion SO-LCA may have great potential for HEIs, helping them to identify hotspots, reduce their social footprint, and raise awareness among the academic community, which undoubtedly contributes to the knowledge, progress, human values, and sustainability these HEIs stand for.This research has been supported by "Ekopol: Iraunkortasunerako Bideak" research group, recognised by the Basque Government (IT-1365-19) and the University of the Basque Country UPV/EHU (GIC-18/22

Dataset on the environmental and social footprint of the University of the Basque Country UPV/EHU

[EN] The organisational life cycle assessment (O-LCA) and the social organisational life cycle assessment (SO-LCA) of the University of the Basque Country UPV/EHU were conducted. The data presented in this paper support the calculation of the environmental and social footprint of the University of the Basque Country UPV/EHU for year 2016 [1] , and may be used as a reference for future calculations of the environmental and social footprint of higher education institutions and other organisations. This dataset provides detailed information on the UPV/EHU and the boundaries considered; on the compilation and quantification of the life cycle inventory (LCI) which included a transport survey conducted in summer 2018-; and on the modelling process followed for the calculation of the environmental and social footprints, based on the ecoinvent 3.3 database [2] and PSILCA-based Soca v1 add-on [3 , 4] , and carried out with the openLCA free software [5] . The dataset also includes the life cycle impact assessment (LCIA) results provided by the CML (baseline, 2015) [6] and ReCiPe (endpoint (H), 2008) [7] LCIA methods and post-processed social impacts provided by the Social Impacts Weighting Method [3] , disaggregated by subprocesses and impact locations. Data is provided for the reference year (2016), and some aggregated data is also provided for alternative scenarios that were explored in order to check pathways to reduce social and environmental impacts of the academic activity of the UPV/EHU [1]To the Sustainability Directorate and the Educational Advisory Service, both belonging to the Vice-Chancellor's Office for Innovation, Social Commitment and Social Action of the University of the Basque Country UPV/EHU, in the context of the Campus Bizia Lab programme (2017/18, 18/19 and 19/20 calls) for the financing of the EHU-Aztarna project. This research has also been supported by 'Ekopol: Iraunkortasunerako Bideak' research group, recognised by the Basque Government (IT-1365-19) and the University of the Basque Country UPV/EHU (GIC-18/22)

The environmental and social footprint of the university of the Basque Country UPV/EHU

This work has calculated the organisational environmental and social footprint of the University of the Basque Country (UPV/EHU) in 2016. First, input and output data flows of the UPV/EHU activity were collected. Next, the environmental and social impacts of the academic activity were modelled, using the Ecoinvent 3.3 database with the PSILCA-based Soca v1 module in openLCA software. In order to evaluate the environmental impacts, CML and ReCiPe LCIA methods were used. The Social Impact Weighting Method was adjusted for the assessment of specific social impacts. The modelling has identified some hotspots in the organisation. The contribution of transport (8,900 km per user, annually) is close to 60% in most of the environmental impacts considered. The life cycle of computers stands out among the impacts derived from the consumption of material products. More than half of environmental impacts are located outside the Basque Country. This work has also made it possible to estimate some of the impacts of the organisational social footprint, such as accidents at work, only some of which occur at the UPV/EHU. Traces of child labour and illiteracy have also been detected in the social footprint that supports the activity of the UPV/EHU. Some of the social and environmental impacts analysed are not directly generated by the UPV/EHU, but they all demand attention and co-responsibility. Based on the modelling performed, this work explores alternative scenarios and recommends some improvement actions which may reduce (in some cases over 30%) the environmental and social impacts of the UPV/EHU's activity. These scenarios and improvement actions will feed a process with stakeholders in the UPV/ EHU based on the Multi-criteria Decision Analysis (MCDA) methodology.To the Sustainability Directorate and the Educational Advisory Service, both belonging to the Vice-Chancellor's Office for Innovation, Social Commitment and Social Action of the University of the Basque Country UPV/EHU, in the context of the Campus Bizia Lab programme (2017/18, 18/19 and 19/20 calls) for the financing of the EHU-Aztarna project. This research has also been supported by 'Ekopol: Iraunkortasunerako Bideak' research group, recognised by the Basque Government (IT1365-19) and the University of the Basque Country UPV/EHU (GIC-18/22)