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Construction activities that include renovation work and energy retrofits add almost twice as much value as the construction of new buildings, and Small and Medium-sized Enterprises (SMEs) contribute more than 70% of the value added in the EU building sector. This article analyses the legislation associated to Nearly Zero Energy Buildings (nZEB) in Spain in order to identify the factors that will leverage their massive implementation. The paper is organized in three main sections: first one, it describes the geographical and social context of nZEB in Spain, then legislative requirements and policies are analysed; and finally, it identifies the training market penetration for nZEB. [ABSTRACT FROM AUTHOR]

This study presents a detailed analysis of thermal comfort and energy consumption in a Passivhaus-certified apartment in Bolueta Tower, Bilbao, Spain, over a period of three years (2020–2022). Utilizing a comprehensive, long-term monitoring approach, the research investigates the effectiveness of the Passivhaus standard in achieving both energy efficiency and occupant comfort in a temperate climate. Using calibrated data loggers to record indoor temperature, humidity, and CO2 levels were used alongside the collection of utility bills to assess energy consumption and thermal comfort, as well as IAQ, against several international standards. Significant issues with overheating were confirmed, in line with previous research. During the warmer months, indoor temperatures frequently exceeded the Passivhaus comfort threshold of 25 °C, reaching as high as 31.3 °C, particularly in the living room and bedroom. This resulted in discomfort during summer, with the percentage of hours above 25 °C reaching 23.21% in 2022. Nighttime temperatures often surpassed 24 °C, impacting sleep quality. Conversely, heating consumption was minimal, corroborating the building's energy efficiency in colder months. The findings highlight a critical gap in the Passivhaus standard when applied in milder climates, where overheating becomes a significant issue. This study suggests the need for an integrated approach in sustainable building design, one that balances energy efficiency with adaptive strategies to mitigate overheating, such as improved natural ventilation and thermal mass. These insights contribute to the ongoing discourse on optimizing energy-efficient buildings for occupant comfort in various climatic conditions. [ABSTRACT FROM AUTHOR]

Buildings are major consumers of energy, accounting for a significant proportion of total energy use worldwide. This substantial energy consumption not only leads to increased operational costs but also contributes to environmental concerns such as greenhouse gas emissions. In the United States, building energy consumption accounts for about 40% of total energy use, highlighting the importance of efficient energy management. Therefore, accurate prediction of energy usage in buildings is crucial. However, accurate prediction of building energy consumption remains a challenge due to the intricate interaction of indoor and outdoor variables. This study introduces the Partitioned Hierarchical Multitask Regression (PHMR), an innovative model integrating recursive partition regression (RPR) with multitask learning (hierML). PHMR adeptly predicts building energy consumption by integrating both indoor factors, such as building design and operational variables, and outdoor environmental influences. Rigorous simulation studies illustrate PHMR's efficacy. It outperforms traditional single-predictor regression models, achieving a 32.88% to 41.80% higher prediction accuracy, especially in scenarios with limited training data. This highlights PHMR's robustness and adaptability. The practical application of PHMR in managing a modular house's Heating, Ventilation, and Air Conditioning (HVAC) system in Spain resulted in a 37% improvement in prediction accuracy. This significant efficiency gain is evidenced by a high Pearson correlation coefficient (0.8) between PHMR's predictions and actual energy consumption. PHMR not only offers precise predictions for energy consumption but also facilitates operational cost reductions, thereby enhancing sustainability in building energy management. Its application in a real-world setting demonstrates the model's potential as a valuable tool for architects, engineers, and facility managers in designing and maintaining energy-efficient buildings. The model's integration of comprehensive data analysis with domain-specific knowledge positions it as a crucial asset in advancing sustainable energy practices in the building sector. [ABSTRACT FROM AUTHOR]

In recent years, there has been growing concern regarding energy efficiency in the building sector with energy requirements increasing worldwide and now responsible for about 40% of final energy consumption in Europe. Previous research has shown that ventilated façades help to reduce energy use when cooling buildings in hot and temperate climates. Of the different ventilated façade configurations reported in the literature, the configuration of ventilated façade with window rarely has been studied, and its 3D thermodynamic behavior is deserving of further analysis and modeling. This paper examines the thermal behavior of an opaque ventilated façade with a window, in experimentally and numerical terms and its impact in energy savings to get indoor comfort. Field measurements were conducted during the winter, spring and summer seasons of 2021 using outdoor full scale test cells located in Seville (southern Spain). The modeling of the ventilated façade was carried out using a three-dimensional approach taking into account the 3D behavior of the air flow in the air cavity due to the presence of the window. The validation and comparison process using experimental data showed that the proposed model provided good results from quantitative and qualitative point of view. The reduction of the heat flux was assessed by comparing the energy performance of a ventilated façade with that of an unventilated façade. Both experimental and numerical results showed that the ventilated façade provided a reduction in annual total energy consumption when compared to the unventilated façade, being compensated the winter energy penalization by the summer energy savings. This reduction is about 21 % for the whole typical climatic year showing the ability of the opaque ventilated façade studied to reduce energy consumption to insure indoor comfort, making its suitable for use in retrofitting the energy-obsolete building stock built in Spain in the middle decades of the 20 century. [ABSTRACT FROM AUTHOR]

The trend in energy consumption, with a particular focus on heating and cooling demand, is an issue that is relevant to the promotion of new energy policies and more efficient energy systems. Moreover, heating and cooling energy demand is expected to rise in the next several decades, mainly due to climate change as well as increasing incomes in developing countries. In this context, the building sector is currently a relevant energy-intensive economic sector in Morocco; it accounts for 33% of the country's total energy demand (as the sector with the second highest energy demand, after the transport sector), with the residential sector accounting for 25% and the tertiary sector accounting for 8%. Aiming to reduce energy dependence and promote sustainable development, the Moroccan government recently issued a comprehensive plan to increase the share of renewables and improve energy efficiency. This strategy includes novel thermal building regulations promoted by the Moroccan Agency for Energy Efficiency. This paper analyzes the thermal behavior and heating-cooling energy demand of a residential building located in Tangier (Morocco) as a case example, based on the country's new thermal regulations and considering specific climatological conditions. A comparison with common Moroccan residential buildings as well as with those in nearby countries with similar meteorological conditions but significant differences in terms of energy demand regulation and requirements, such as Spain, is also included. Simulations were carried out using the DesingBuilder and EnergyPlus Software packages. According to the results, the last building thermal regulation requirements in Morocco need to be revised and extended in order to achieve the energy efficiency objectives established by the Moroccan government for 2030. [ABSTRACT FROM AUTHOR]

This paper performs technical, economic and environmental feasibility analyses of two different solar cogeneration plants, consisting of a solar system (a parabolic trough collector field coupled with thermal energy storage), an Organic Rankine Cycle (ORC), and mechanical chillers, that should cover the electrical and cooling demands of a commercial center located in Zaragoza (Spain). System A is hybridized with an auxiliary biomass boiler that complements the solar system's thermal production, providing a constant heat supply to the ORC, which operates at full load during the operating hours of the solar system. In contrast, system B is not hybridized with biomass, so the ORC is fully driven by the solar system, operating at partial load according to the solar resource availability. Both systems are connected to the electrical grid, allowing electricity purchases and sales when needed. The design procedure involves the sizing of the equipment as well as the modelling of the hourly behavior of each system throughout the year. The physical analysis is complemented by an economic assessment, which considers investment and variable costs, as well as an estimate of the significant environmental benefits of the proposed plants. The solar plants are compared to a conventional system in which all the electrical consumption is covered with electricity purchased from the grid. The costs of the electricity produced by systems A and B are estimated at 0.2030 EUR/kWh and 0.1458 EUR/kWh, which are about 49% and 7% higher than the electricity purchase price in Spain (0.1363 EUR/kWh). These results indicate that while none of the solar plants are presently competitive with the conventional system, system B (without biomass hybridization) is actually closer to economic feasibility in the short and medium term than system A (with biomass hybridization). [ABSTRACT FROM AUTHOR]

Post-occupancy evaluations are common tools used to periodically assess Indoor Environmental Quality (IEQ) in tertiary buildings. Although the large amount of data collected from surveys contain valuable information, the influence of building characteristics on IEQ considering the different uses of the rooms and different types of occupants is rarely considered in the evaluation. This study presents an analysis of the association between building characteristics and IEQ in different building rooms (classrooms and offices) and different occupants (students and lecturers) using a post occupancy evaluation survey to 1013 occupants in 26 higher educational buildings in Spain under a Mediterranean climate. This research demonstrated that building characteristics influence IEQ perceptions of the different rooms in tertiary education buildings. The possibility of controlling the lighting, shadows or heating, ventilation air or conditioning (HVAC) systems are the most influential factors when analyzing IEQ. The findings of this research are of interest to facility managers aiming at implementing energy efficiency measures based on user-centric satisfaction or developing maintenance plans focused on IEQ enhancement. [ABSTRACT FROM AUTHOR]