Proposal for Prioritizing the Retrofitting of Residential Buildings in Energy Poverty Circumstances

The energy poverty derived from socio-economic imbalances affects mostly households with fewer economic resources, being social housing complexes one of the most vulnerable sectors. The insufficient access to energy and the incapability to maintain dwellings at an adequate temperature can have negative impact on people’s health due to the prolonged exposure to poor hygrothermal conditions. Therefore, the prioritization of building retrofitting actions must be carried out regarding the actual state of the housing and the family economy. This paper proposes the definition of a prioritization map that gave a general knowledge of the energy vulnerability situation of the existing building stock. To this end, the dwelling’s energy performance is analysed, focusing on the correlation among its characteristics and the energy vulnerability of its inhabitants. In this way, dwellings with high energy poverty potential are identified in order to develop different energy retrofitting strategies. By applying this method to 14 case studies of social housing in Bilbao, Spain, it was obtained a prioritization map with six levels of vulnerability that can serve as a tool for public entities to design their future strategies. It has been proven that building compactness and year of construction are important factors with a great impact on the heating demand and final consumption in dwellings. Acknowledging the vulnerability context of the building stock eases the decision-making process and the definition of intervention guidelines, prioritizing those in a situation of greater vulnerability

Data on records of indoor temperature and relative humidity in a University building

Good indoor comfort and air quality are essential for correct educational development. Most reports in this field focus on primary and secondary school buildings, with numerous projects conducted in the Mediterranean Zone. However, little has been done in the context of university buildings. Data on indoor temperature and relative humidity data acquired trough field surveys of a seminar room located in the Architecture Faculty in San Sebastian (Spain) is provided in this paper. The seminar room was monitored during a typical spring week. The data presented in the article are related to the research article entitled Retrofit strategies towards Net Zero Energy Educational Buildings: a case study at the University of the Basque Country (Ref. 0378-7788)

Construcción 3. Construcción industrializada

Nivel educativo: Grado. Duración (en horas): Más de 50 horasEl campo formativo de la asignatura Construcción 3 corresponde a la construcción industrializada (proceso de industrialización y sistema de cimientos y estructuras) y es quizás el más dinámico dentro del ámbito de la edificación debido a su vinculación directa con la innovacion productiva, implícita en el término "industrialziación". Con el tiempo el panorama ha cambiado profundamente, la industrialización se extendió primeramente a todos los ámbitos de la actividad edificatoria, incluida la obra “in situ”. Después el propio concepto de industrialización ha evolucionado para convertirse en herramienta del cambio que se está produciendo hacia la construcción ecoeficiente, en la que las exigencias de evaluación, registro, verificación y certificación de los procesos la convierten en estratégica. En los próximos años la necesidad de dotar de inteligencia a todo el ámbito edificatorio para garantizar su ecoeficiencia exigirá que la industrialización evolucione profundamente para seguir cumpliendo su misión de seguir siendo el soporte material de la arquitectura. En pocos años el panorama ha cambiado profundamente, y mientras los cerrados sistemas de prefabricación pesada han derivado en general hacia la producción de elementos tipificados simples utilizados en ámbitos específicos, la construcción tradicional ha experimentado una profunda modificación en sus estructuras organizativas, productivas y tecnológicas, y el grado de innovación se multiplica geométricamente. Actualmente no existe total dicotomía entre metodologías edificatorias artesanas e industrializadas sino un ámbito de actuación complejo en el que coexisten e interaccionan metodologías con diferentes concepciones y grados de industrialización. Esta situación se ha reflejado en una modificación progresiva de la enseñanza sobre construcción industrializada, que en la actualidad pretende formar al alumno en la utilización responsable de nuevas tecnologías y por lo tanto en la adopción de metodologías que permitan alcanzar el máximo compromiso ambiental y la máxima eficiencia edificatoria, medidos ambos de un conjunto amplio de parámetros

Decision-making framework for positive energy building design through key performance indicators relating geometry, localization, energy and PV system integration

The effectiveness of positive energy building (PEB) design largely depends on a balanced approach between building design and energy performance. The current common architectural process is lacking guidelines to address the impact of early design decisions in achieving the energy positive building goals. A selection of case study office buildings with an intended architectural diversity provide homogenized real data for this research. The aim is to find connections among four fields that are relevant for the PEB design process: building geometry, location, energy consumption and building integrated photovoltaics. The interrelations among them are synthesized in several novel key performance indicators (KPIs) that conclude, i.a., that only buildings with a roof-to-façade area ratio higher than 28% may achieve a 100% self-sufficiency. The PV area corresponding to 15% of the envelope is a necessary starting threshold to achieve a self-sufficient PEB. The installed power capacity of the PV system should be above 30 Wp/m2c. The main contribution is a decision-making framework that can be sequentially applied providing useful limits, thresholds and figures that guide towards effective architectural decisions for PV system integration in the early PEB design process

Energy balance and photovoltaic integration in positive energy buildings. Design and performance in built office case studies

Solar design will be reshaping the architecture as one way to address the global climate crisis and the reduction of fossil fuel consumption. This paper analyses the current definition of Positive Energy Building (PEB) and a selection of both NZEB and PEB built projects with real monitored data, discussing their design features and potential for achieving positive energy balance. The research aims to assess an optimal ratio between PV area in both roof and façade, net floor building area and achieved self-sufficiency ratios in office buildings. The study shows that most of the buildings’ PV systems have an area equal to 10-20% of the total building’s net floor area. Buildings that have PV to area ratio from 13 to 20% are self-sufficient from 100 to 150%. PV installation in the façades results decisive for reaching positive energy balance. The relation of the PV system installed on the façade to PV system on the roof is from 50 to 57 % for the studied buildings. Buildings located in sites with higher GHI tend to have lower PV area ratios and a ratio of 20% or more is valid for all the studied sites to achieve electrical energy self-sufficiency

The zero building: an exemplary nearly zero energy office building (NZEB) and its potential to become a positive energy building (PEB)

European energy policies introduced nearly zero energy building (NZEB) design to stimulate the energy transition in buildings, and EU programs promote the evolution towards positive energy buildings (PEB). Most studies into NZEBs are based on simulations, and not on real monitoring data. This paper presents the real performance data of the Zero building, an NZEB office building with Leed Gold and Breeam Excellent environmental design certifications located in a neighbourhood that shares a zero-emission district heating-cooling facility relying only on 100% renewable energy sources. The current performance of the building and its neighbourhood is assessed to identify the existing gap to reach the goals of next generation buildings, namely positive energy buildings (PEB), which will not consume fossil fuels and will achieve energy self-sufficiency at the neighbourhood scale. A study the occupied zero building in operation for one year showed that it achieved a degree of self-sufficiency of 74.3% for the operational electric energy thanks to its PV roof-façade. The results show that its carbon footprint is only 3.35 kgCO2/m2y, 92% lower than in a typical office building in locations with the same climate

Arquitectura ecoeficiente. Tomo II

203 p.Descargas previas 134 La sostenibilidad y su relación con la ecología y la biodiversidad, con la arquitectura bioclimática y con las instalaciones eficientes, no es una opción hoy en día, es un compromiso de todos y una obligación moral. La arquitectura es un diente importante en ese engranaje que nos puede dirigir a un futuro viable o al abismo. Los edificios han sido y siguen siendo grandes consumidores directos de recursos, energía, agua, materiales, alimentos, y consumidores indirectos de otros recursos contaminantes, como los vinculados al transporte. Este libro aborda el problema de la sostenibilidad y la ecoeficiencia de manera amplia y variada, desde diversas perspectivas, lo que implica las visiones diferentes necesarias para resolver los problemas que tenemos. De no hacerlo así seguiremos el camino de la "sexta extinción" que señala esa falta de equilibrio entre las necesidades de las especies, en este caso la humana, y los recursos que consumimos a un ritmo muy superior a la capacidad de la Tierra para reponerlos. Sigamos las líneas que marcan estos magníficos textos, con instalaciones eficientes generadoras de energía, como los cogeneradores o las superficies radiantes, el uso de recursos renovables como la biomasa y abundemos en la rehabilitación de nuestras ciudades para consumir menos materiales

On the energy potential of daytime radiative cooling for urban heat island mitigation

The objective of this paper is to present the potential of daytime radiative cooling materials as a strategy to mitigate the Urban Heat Island effect. To evaluate the cooling potential of daytime radiative cooling materials, 15 theoretical materials and seven existing materials were simulated: two radiative cooling materials, a coolmaterial, two white paints, a thermochromic paint and a construction material. The novelty of this study is that it shows that the optimal spectral characteristics of radiative cooling materials depending on the climate conditions and the type of application. A sensitivity analysis was performed to evaluate the impact of each wavelength emissivity on the ability to achieve sub-ambient radiative cooling. The sensitivity analysis comprised a total of 90 theoretical materials with 15 different wavelength combinations and 6 emissivity values. The heat transfer model, which includes conduction, convection, and radiation, was developed using a spectrally-selective sky model. Two conditions were considered: a very conductive surface and a highly insulated one. All the materials were simulated in two cities that suffer from the Urban Heat Island effect—Phoenix and Sydney. The mean surface temperature reduction achieved was 5.30 ◦C in Phoenix and 4.21 ◦C in Sydney. The results presented suggest that the type of application (active or passive) is a determinant factor in the design of radiative cooling materials. Modifying the spectra of the materials led to a substantial change in the cooling potential. A material that performs well in a dry climate as a passive solution could perform poorly as an active solution.Laura Carlosena would like to acknowledge the funding of the Government of Navarre for an industrial Ph.D. research grant "Doctorados industriales 2018–2020" file number 0011-1408-2017-000028 at the University of the Basque Country that takes place in the R + D department of Alonso Hernández & asociados arquitectura S.L

Arquitectura ecoeficiente. Tomo II

203 p.Descargas previas 134 La sostenibilidad y su relación con la ecología y la biodiversidad, con la arquitectura bioclimática y con las instalaciones eficientes, no es una opción hoy en día, es un compromiso de todos y una obligación moral. La arquitectura es un diente importante en ese engranaje que nos puede dirigir a un futuro viable o al abismo. Los edificios han sido y siguen siendo grandes consumidores directos de recursos, energía, agua, materiales, alimentos, y consumidores indirectos de otros recursos contaminantes, como los vinculados al transporte. Este libro aborda el problema de la sostenibilidad y la ecoeficiencia de manera amplia y variada, desde diversas perspectivas, lo que implica las visiones diferentes necesarias para resolver los problemas que tenemos. De no hacerlo así seguiremos el camino de la "sexta extinción" que señala esa falta de equilibrio entre las necesidades de las especies, en este caso la humana, y los recursos que consumimos a un ritmo muy superior a la capacidad de la Tierra para reponerlos. Sigamos las líneas que marcan estos magníficos textos, con instalaciones eficientes generadoras de energía, como los cogeneradores o las superficies radiantes, el uso de recursos renovables como la biomasa y abundemos en la rehabilitación de nuestras ciudades para consumir menos materiales

Experimental development and testing of low-cost scalable radiative cooling materials for building applications

Urban overheating has a serious impact on building energy consumption. Daytime radiative cooling materials are an interesting passive solution for refrigeration. However, their costs and complex manufacturing hinder their current application. In this study, a series of scalable and lowcost daytime radiative cooling (DTRC) materials were designed, fabricated, and tested in a moderate climate (Cfb-Köppen-Geiger classification) and compared to aluminum and Vikuiti. The methodology was: i) material selection and design, (ii) optimization, (iii) fabrication, (iv) characterization, and (v) testing. The materials were fabricated using different substrates, aluminum and Vikuiti, and two kinds of formulations for the emissive layers based on silica-derived polymer polymethylsilsesquioxane (PMSQ) with embedded silica nanoparticles. The resulting aluminum DTRC materials had a mean solar reflectivity of 0.7 and 0.34 emissivity in the atmospheric window, the samples with Vikuiti had 0.97 and 0.89, respectively. During the experiment, the samples were exposed to different ambient conditions without a convection barrier and were contained in an extruded polystyrene board to eliminate conduction. The samples reached 7.32 °C and 9.13 °C maximum surface temperature reduction (below ambient) during the day and night, respectively. The samples with the commercial substrate achieved a mean reduction of 3.72 °C below ambient temperature. Although the aluminum samples did not achieve subambient cooling throughout the entire day, the emissive layer reduced the sample's surface temperature by an average of 1.7 °C. The PMSQ radiative cooling materials show great potential for future building applications. Suitability under different climates and experimental settings should be done to test broad applicability.The materials development in this research received a grant from the Government of Navarre "Convocatoria proyectos I + D 2019" file number 0011-1365-2019-000051; and financial support from Alonso Hernandez & asociados arquitectura, S. L