Grup de Recerca en Energia i Intel·ligència Artificial (GREiA) (INSPIRES)

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The GREiA research group (Research group in energy and artificial intelligence) is born from the union of the research group in energy GREA and the research group in artificial intelligence IA. The collaboration of these two groups begins in 2014. The general line of research that defines the activity of the group is to provide answers and solutions related to the fields of energy engineering, industrial and construction design, sustainability and intelligence artificial. [Més informació]

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Now showing 1 - 5 of 519
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    Open Access
    How internal heat loads of buildings affect the effectiveness of vertical greenery systems? An experimental study
    (Elsevier, 2020) Coma Arpón, Julià; Chàfer, Marta; Pérez Luque, Gabriel; Cabeza, Luisa F.
    Nature-based solutions applied to the building skin, such as green roofs and vertical greenery systems, are standing out as the most promising by contributing with thermal improvements at building scale. From previous research done by GREiA research group at the University of Lleida (Spain), energy savings up to 58% were obtained by implementing vertical greenery systems on external building walls for cooling purposes. However, since there exist other passive and active energy saving technologies in the literature review that were limited their cooling and heating capacity after implementing internal heat loads, new experimental tests for two different vertical greenery systems simulating the heat loads in both, summer and winter were conducted in this research. Additionally, these experiments also improve the scarce and controversial literature for winter conditions. The results demonstrated that considering internal loads in experimental investigations is crucial for the results of the effectiveness of the green walls and green facades. The energy savings of VGS were reduced between 22.5% and 26.7% because of the internal loads for cooling purposes, and increased about 3.6% and 3.1% for heating.
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    Open Access
    Use of Textile Fiber Waste to Improve the Thermal and Mechanical Performance of Cement-Based Mortar
    (2024) Ayed, Rabeb; Borri, Emiliano; Zsembinszki, Gabriel; Bouadila, Salwa; Cabeza, Luisa F.; Lazaar, Mariem
    Improving the thermal properties of materials used in buildings is crucial to reducing energy demand and consumption. This study investigated the use of textile fiber waste in cement-based composites for construction applications. Mechanical and thermal characterizations were carried out to assess the behavior of cement mortars with different percentages of two types of textile fibers after 7 and 28 days of water hardening. The results show that the incorporation of fibers can significantly improve the thermal insulation capacity of buildings by reducing the thermal conductivity of cement mortar by up to 52%. In addition, the use of textile fibers can improve themechanical strength of the cement mortar, especially with a high fiber content and a longer curing time.
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    Embargo
    Energy saving potential of variable thermophysical envelope energy storage technologies in different climatic regions
    (Elsevier, 2024) Ji, Pengcheng; Guo, Yong; Weschler, Louise B.; Cabeza, Luisa F.; Zsembinszki, Gabriel; Yang, Rui; Zhang, Yinping
    Climate change mitigation necessitates higher use of renewable energy in buildings instead of fossil fuels. There is great potential to achieve this goal when the thermophysical properties of a building envelope are variable. To identify the ideal variable thermophysical properties (specific heat and thermal conductivity) for building envelopes located in given climate regions, an inverse problem approach based on particle swarm optimization (PSO) was employed. The energy consumptions of rooms were calculated when the building envelope thermophysical properties are ideally variable or constant for seven representative cities located in five climatic regions in China. The results show that when the thermal conductivity of exterior wall is ideally variable, the energysaving ratio can reach 7-15 % in seven cities, corresponding to energy saving amount of 0.03-0.78 kgce/(m2⋅year), and when the specific heat of interior building envelope is ideally variable, the energy saving ratio can reach 37-100 %, corresponding to energy saving amount of 0.21-3.06 kgce/(m2⋅year). The corresponding annual CO2 emission reduction is between 0.02 and 1.90 kg/(m2⋅year) and between 0.10 and 8.07 kg/(m2⋅year), respectively. Variable thermophysical properties have highest energy-saving and CO2 emission reduction potential in the severe cold region. Conversely, in the moderate temperature region, their impact is insignificant. The present study can help to provide direction for developing materials ith variable thermophysical properties for building envelopes in different climate regions.
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    Open Access
    Evaluation of the social impact of an energy system for residential heating applications based on a novel seasonal thermal energy storage
    (Elsevier, 2024) Borri, Emiliano; Zsembinszki, Gabriel; Cabeza, Luisa F.
    Thermal energy storage (TES) is a key player in the energy transition to support the integration of renewable sources and reduce the energy demand supplied by fossil fuels. The EU-funded project SWS-Heating aims to develop a novel seasonal thermal energy storage based on selective water sorbents for domestic heating to increase the share of renewables. Although the main performance indicator of new technologies is energy efficiency optimization, social impact of TES is an overlooked aspect representing a strong barrier to market deployment of novel technologies. Therefore, this study uses social life-cycle assessment (S-LCA) techniques to evaluate the social impact of the proposed systems described above. The inventory developed in this study is based on qualitative data from industrial companies involved in the different stages of the system life cycle. Results showed that the system has a medium-high social impact with great potential for improvement especially in the manufacturing and end-of-life stages. In particular, to increase the value of social impact more effort should be put by companies to strengthen the engagement with local communities and support sustainability with value chain actors.
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    Open Access
    Thermal Energy Storage Using Phase Change Materials in High-Temperature Industrial Applications: Multi-Criteria Selection of the Adequate Material
    (MDPI, 2024) Cabeza, Luisa F.; Martínez, Franklin R.; Borri, Emiliano; Ushak, Svetlana; Prieto, Cristina
    Thermal energy storage (TES) plays an important role in industrial applications with intermittent generation of thermal energy. In particular, the implementation of latent heat thermal energy storage (LHTES) technology in industrial thermal processes has shown promising results, significantly reducing sensible heat losses. However, in order to implement this technology, a proper selection of materials is important. In this study, a new multi-criteria phase change material (PCM) selection methodology is presented, which considers relevant factors from an application and material handling point of view, such as hygroscopicity, metal compatibility (corrosion), level hazard, cost, and thermal and atmospheric stability. The methodology starts after setting up the system requirements where the PCM will be used, then a material screening is able to find all possible candidates that are listed with all available properties as listed before. Then, a color map is produced, with a qualitative assessment of material properties drawbacks, hazard level, melting enthalpy, and price. The experimentation starts with a preliminary set of tests on hygroscopicity and one-week corrosion test, which allows disregarding PCMs and selecting a short list of potential PCMs that would need further characterization before the final selection.