Authors: Hernandez-Cruz, Pablo ^a, Flores-Abascal, Ivan ^a , Hidalgo-Betanzos, Juan María ^b, Almeida, Manuela ^c, Erkoreka-González, Aitor ^a

^a ENEDI Research Group, Energy Engineering Department, Faculty of Engineering of Bilbao, University of Basque Country UPV/EHU, Plaza Torres Quevedo 1, Bilbao, Spain

^b ENEDI Research Group, Department of Energy Engineering, University of the Basque Country (UPV/EHU), Nieves Cano 12, Araba, 01006, Spain

^c University of Minho, ISISE, ARISE, Department of Civil Engineering, Campus de Azurém, Guimaraes, 4800-058, Portugal

Journal of Building Engineering, December 2024

Keywords: Social housing buildings, Building renovation, Climate change, LCIA, Real consumption

Abstract: The renovation of social housing buildings, a priority for the European Union, must be assessed under a Climate Change (CC) context. This work, centred on the user and the environmental impact, analyses the climate resilience of the renovation of the social housing building stock of the Basque Country, located in Northern Spain. In this region, characterised by cold winters and mild summers, CC projections indicate a moderate warming even in the worst-case scenario. The assessment of passive renovation actions indicates that reducing heating demand is key no matter the CC scenario. The reduction achieved in heating demand with deep passive renovations is up to 82.2 % when the worst CC scenario is considered. Indeed, since low-income tenants occupy these buildings, it has been found that global warming would help users achieve indoor standard conditions in a more effective way than with passive renovation actions. Consequently, to improve indoor conditions independently of the CC scenario, active renovation measures must also be considered. Furthermore, the thermal comfort analysis proved that the risk of overheating in this region is negligible, with less than 4 % of the yearly hours above 26 °C. Finally, the Life Cycle Impact Assessment shows that the environmental impact of the renovation is short when compared to the impact of the operational stage. The use of conventional or ecological materials during renovation would save up to 6.5 % of Non-Renewable Primary Energy Consumption and 3.7 % of CO2 emissions during the life-cycle of the building.

https://doi.org/10.1016/j.jobe.2024.111164

Authors: Hernandez-Cruz, Pablo ^a, María Hidalgo-Betanzos, Juan ^b , Flores-Abascal, Ivan ^a, Erkoreka-Gonzalez, Aitor ^a, Fernandez-Luzuriaga, Jon ^b

^a ENEDI research group, Energy Engineering Department, Faculty of Engineering of Bilbao, University of Basque Country UPV/EHU, Pl. Ingeniero Torres Quevedo 1, Bilbao, Spain

^b ENEDI Research Group, Department of Energy Engineering, University of the Basque Country (UPV/EHU), Nieves Cano 12, Araba, 01006, Spain

Energy and Buildings, Open Access, September 2024

Keywords: Building renovation, Social housing building, Energy performance gap, Real consumption effect, Life cycle cost assessment

Abstract: Social housing is a priority within the European Union (EU) for boosting the necessary building renovation. The predicted and real consumption of buildings usually differ, and this is the Energy Performance Gap (EPG). Here, the effect the EPG has on the renovation decision-making process is analysed. The results show that a significant error in energy consumption reduction can occur if real consumption is not considered. Generally, it has been found that the average difference between considering real consumption or not is 22 percentage points. The economic perspective of the renovation is therefore influenced by the tenants’ real consumption and some renovation scenarios can become non-profitable or vice-versa. However, considering real consumption is complex and time consuming, so a simplified methodology intended for use by investors or administrators without considerable effort is proposed. This methodology has been proved to be reliable, accounts for real consumption, and allows a more accurate assessment of building renovation. Particularly, when real consumption is considered, the actual contribution of the building’s renovation regarding CO2 emissions reduction targets can be properly assessed. Finally, the improvement in the dwellings’ indoor conditions is analysed, as a key additional aspect to support the EU priority to renovate social housing.

https://doi.org/10.1016/j.enbuild.2024.114535

Authors: Giraldo-Soto, Catalina ^a, Erkoreka, Aitor ^a , Mora, Laurent ^b, Uriarte, Amaia ^c, Eguía-Oller, Pablo ^d, Gorse, Christopher ^e

^a ENEDI research group, Energy Engineering Department, Faculty of Engineering of Bilbao, University of Basque Country UPV/EHU, Pl. Ingeniero Torres Quevedo 1, Bilbao, Spain

^b I2M – Institute of Mechanics and Engineering, University of Bordeaux CNRS (UMR 5295), Site ENSAM, Esplanade des Arts et Métiers, Talence, France

^c TECNALIA, Basque Research and Technology Alliance (BRTA), Edificio 700 Parque Tecnológico de Bizkaia, Derio, Spain

^d Department of Mechanical Engineering, Heat Engines and Fluids Mechanics, Industrial Engineering School, University of Vigo (Universidade de Vigo), Vigo, Spain

^e School of Architecture Building & Civil Engineering, Loughborough University, Leicestershire, United Kingdom

Journal of Building Physics, Open Access, August 2024

Keywords: Outdoor air temperature, uncertainty, measurement, monitoring system

Abstract: Outdoor air temperature represents a fundamental physical variable that needs to be considered when characterising the energy behaviour of buildings and its subsystems. Research, for both simulation and monitoring, usually assumes that the outdoor air temperature is homogeneous around the building envelope, and when measured, it is common to have a unique measurement representing this hypothetical homogeneous outdoor air temperature. Furthermore, the uncertainty associated with this measurement (when given by the research study) is normally limited to the accuracy of the sensor given by the manufacturer. This research aims to define and quantify the overall uncertainty of this hypothetical homogeneous outdoor air temperature measurement. It is well known that there is considerable variability in outdoor air temperature around the building and measurements are dependent on the physical location of outdoor air temperature sensors. In this research work, this existing spatial variability has been defined as a random error of the hypothetical homogeneous outdoor air temperature measurement, which in turn has been defined as the average temperature of several sensors located randomly around the building envelope. Then, some of these random error sources which induce spatial variability would be the cardinal orientation of the sensor, the incidence of solar radiation, the outdoor air temperature stratification, the speed and variations of the wind and the shadows of neighbouring elements, among others. In addition, the uncertainty associated with the systematic errors of this hypothetical homogeneous outdoor air temperature measurement has been defined as the Temperature Sensor Uncertainty where this uncertainty is associated with the sensor’s accuracy. Based on these hypotheses, a detailed statistical procedure has been developed to estimate the overall Temperature Uncertainty ) of this hypothetical homogeneous outdoor air temperature measurement and the Temperature Sensor Uncertainty . Finally, an uncertainty decoupling method has also been developed that permits the uncertainty associated with random errors (Temperature’s Spatial Uncertainty ) to be estimated, based on and values. The method has been implemented for measuring the outdoor air temperature surrounding an in-use tertiary building envelope, for which an exterior monitoring system has been designed and randomly installed. The results show that the overall Temperature Uncertainty for the whole monitored period is equal to ±2.22°C. The most notable result is that the uncertainty associated with random errors of measurement (Temperature’s Spatial Uncertainty ) represents more than 99% of the overall uncertainty; while the Temperature Sensor Uncertainty , which is the one commonly used as the overall uncertainty for the outdoor air temperature measurements, represents less than 1%.

https://doi.org/10.1177/17442591241269195