Bridging the gap between the predicted and actual energy performance of buildings is necessary to... more Bridging the gap between the predicted and actual energy performance of buildings is necessary to increase the energy performance of existing buildings and achieve the European Union’s energy efficiency targets in the “2030 climate & energy framework”. Construction is considered the sector with the most potential for energy saving. Specifically, buildings space heating has considerable potential for energy saving. Thermal transmittance is the fundamental parameter to characterise the heat losses of building envelopes. However, several research authors evidenced that assumptions regarding heat loss from a home pre-retrofit and post-retrofit were incorrect. In this sense, accurate on-site measurements are necessary to provide information on the actual thermal transmittance of façades. The purpose of this thesis is to contribute to reduce the energy performance gap of residential buildings. Therefore, the aim of the thesis is to enhance the accuracy of in situ measurements of the actua...
espanolLa armonizacion de los diferentes estudios universitarios en Europa y la creacion del EEES... more espanolLa armonizacion de los diferentes estudios universitarios en Europa y la creacion del EEES ha supuesto un cambio de mentalidad en el diseno los nuevos planes de estudios y en la forma de contabilizar el proceso ―ensenanza-aprendizaje‖, al tener en cuenta el tiempo global del trabajo del estudiantado, y no solo el tiempo en el aula. La ponencia pretende analizar las implicaciones de la implantacion del modelo EEES en un caso de ensenanzas tecnicas, mediante comparacion del rendimiento del estudiantado en los modelos pre y post EEES. ?El cambio se traduce en un mayor rendimiento y una mejora en el aprendizaje? El Grado en Ingenieria de Edificacion en la EPSEB (UPC) realizo la adaptacion en bloque de los estudios de Arquitectura Tecnica en el curso 09/10. Ello lo convierte en un observatorio privilegiado porque gran parte del estudiantado ha experimentado ambos modelos. Para realizar el estudio se analiza la evolucion del rendimiento academico en asignaturas basicas y especifica...
Within the European framework, the passive house has become an essential constructive solution in... more Within the European framework, the passive house has become an essential constructive solution in terms of building efficiency and CO2 reduction. However, the main approaches have been focused on post-occupancy surveys, measurements of actual energy consumption, life-cycle analyses in dynamic conditions, using simulation, and the estimation of the thermal comfort. Few studies have assessed the in situ performance of the building fabric of passive houses. Hence, this paper explores the applicability of non-destructive techniques—heat flux meter (HFM) and quantitative infrared thermography (QIRT)—for assessing the gap between the predicted and actual thermal transmittance of passive house façades under steady-state conditions in the Mediterranean climate. Firstly, the suitability of in situ non-destructive techniques was checked in an experimental mock-up, and, subsequently, a detached house was tested in the real built environment. The findings revealed that both Non-Destructive Test...
Buildings play a central role in the clean energy transition, which is why it is vital to underst... more Buildings play a central role in the clean energy transition, which is why it is vital to understand how energy is consumed in this sector. Energy performance certificate databases are considered a key source of information on the characteristics of built building stock. Despite a growing portfolio of studies based on information from such databases, little is known about energy consumption in offices. This paper explores the modelled energy performance of existing offices in Spain, using data from 13,701 energy performance certificates collected by the Catalan Institute of Energy (ICAEN) in 2013–2018. Offices were found to consume between 202.66 and 212.10 kWhp/m2·year and were mostly ranked in classes C and D (~64%). Offices with E, F or G labels represent ~28% of the sample while A and B energy ratings are very scarce (~8%). Key drivers of energy consumption variation were found to be the office type, construction period, climate zone, renewable energy use, energy certification p...
LCA inventory analysis for assessing the environmental impact related to the implementation of en... more LCA inventory analysis for assessing the environmental impact related to the implementation of energy retrofitting measures in representative offices, including office blocks and offices in industrial buildings and offices in residential buildings.
Abstract Considering the progressive population aging, the fact that old people spend around 90% ... more Abstract Considering the progressive population aging, the fact that old people spend around 90% of their time indoors and the high energy expenditure of heating systems, thermal comfort in nursing homes should be analysed. The aim of this study is to analyse the thermal comfort during the winter of elderly people living in nursing homes (residents) and compare it with the thermal comfort of caregivers and therapists (non-residents). Longitudinal field measurements were conducted in 25 common rooms of five nursing homes in a Mediterranean climate during the winter, from January to March 2019. Room air temperature (Ta), relative humidity (HR%), mean radiant temperature (Tr) and air velocity (va) were recorded using a Delta Ohm HD32.1 instrument with an anemometer, thermometer and a black globe thermometer. “Right-here-right-now” thermal responses of occupants were collected using a face-to-face questionnaire delivered intermittently. A total of 881 questionnaires were collected and then matched against concurrent indoor and outdoor thermal conditions. The results indicate that residents of nursing homes in the Mediterranean climate were less sensitive to variations in room temperature than therapists and caregivers, and less sensitive than found in previous studies conducted in non-elderly adults. The neutral temperature for residents was 21.6°C while for caregivers and therapists it was 21.9°C. The results also showed that clothing adaptation to the activity of caregivers would increase their thermal comfort and might help thermal adaptation to residents’ thermal needs. The modification of temperature setpoints in nursing homes based on the results of this study could influence energy use and should be carefully considered by policy makers and nursing homes’ facility managers.
Abstract In situ measurements of low thermal transmittance facades are required to ensure complia... more Abstract In situ measurements of low thermal transmittance facades are required to ensure compliance with energy performance strategies for new nearly zero-energy buildings (nZEB) and with energy policies for the transition of existing building stock to nZEB. The aim of this paper was to enhance the accuracy of the in situ measurement of low U-value facades, employing the widely used ISO 9869-1:2014 HFM method and exploring the limits of its conditions. To refine the testing conditions, three variables were analysed and compared with indications of ISO 9869-1:2014 and the existing literature: the temperature difference, the test duration and the accuracy of equipment. A continuous experimental campaign was conducted in a building mock-up. The findings showed that to accurately measure in situ low U-value facades, the temperature differences must be greater than those indicated in the existing literature. Temperature differences above 19 °C required a test duration of 72 h, while for lower temperature differences the test duration must be prolonged. The accuracy of temperature sensors had a greater impact on the accuracy of measurement in the initial cycles of the test. Likewise, the accuracy of ambient temperature sensors was found to have a considerable influence on the uncertainty of measurements.
Exceptional pandemic lockdown measures enabled singular experiments such as analysing the energy ... more Exceptional pandemic lockdown measures enabled singular experiments such as analysing the energy consumption of vacant buildings. This paper assesses the impact of the COVID-19 lockdown on the energy use of academic buildings. For this purpose, weather-adjusted energy use was compared before and during the lockdown, including different levels of lockdown restrictions. Results obtained for the 83 academic buildings of Universitat Politècnica de Catalunya-Barcelona Tech (UPC) reveal that the avoided energy consumption amounted to over 4.3 GWh during the post-pandemic year. However, the results indicate that academic buildings were still using approximately 46.9% of their typical energy consumption during strict lockdown. This revelation emphasizes the high environmental burden of buildings, regardless of whether they are occupied.
Accurate information on the actual thermal transmittance of walls is vital to select appropriate ... more Accurate information on the actual thermal transmittance of walls is vital to select appropriate energy-saving measures in existing buildings to meet the commitments of the European Green Deal. To obtain accurate results using the heat flow meter (HFM) method, good thermal contact must be made between the heat flow meter plate and the wall surface. This paper aimed to assess the influence of the non-perfect thermal contact of heat flow meter plates on the accuracy of in situ measurement of the façades’ U-value when a film was applied to avoid damage to the wall surface. Given the fact that to avoid harm to the wall surface, the laying of a film is a usual procedure in the installation of equipment during the building’s operational stage. The findings show that deviations between measured U-values when an HFM was installed directly on the wall surface and when an HFM was installed with a PVC film were found to differ significantly from the theoretical effect of including a PVC film d...
Bridging the gap between the predicted and actual energy performance of buildings is necessary to... more Bridging the gap between the predicted and actual energy performance of buildings is necessary to increase the energy performance of existing buildings and achieve the European Union’s energy efficiency targets in the “2030 climate & energy framework”. Construction is considered the sector with the most potential for energy saving. Specifically, buildings space heating has considerable potential for energy saving. Thermal transmittance is the fundamental parameter to characterise the heat losses of building envelopes. However, several research authors evidenced that assumptions regarding heat loss from a home pre-retrofit and post-retrofit were incorrect. In this sense, accurate on-site measurements are necessary to provide information on the actual thermal transmittance of façades. The purpose of this thesis is to contribute to reduce the energy performance gap of residential buildings. Therefore, the aim of the thesis is to enhance the accuracy of in situ measurements of the actua...
espanolLa armonizacion de los diferentes estudios universitarios en Europa y la creacion del EEES... more espanolLa armonizacion de los diferentes estudios universitarios en Europa y la creacion del EEES ha supuesto un cambio de mentalidad en el diseno los nuevos planes de estudios y en la forma de contabilizar el proceso ―ensenanza-aprendizaje‖, al tener en cuenta el tiempo global del trabajo del estudiantado, y no solo el tiempo en el aula. La ponencia pretende analizar las implicaciones de la implantacion del modelo EEES en un caso de ensenanzas tecnicas, mediante comparacion del rendimiento del estudiantado en los modelos pre y post EEES. ?El cambio se traduce en un mayor rendimiento y una mejora en el aprendizaje? El Grado en Ingenieria de Edificacion en la EPSEB (UPC) realizo la adaptacion en bloque de los estudios de Arquitectura Tecnica en el curso 09/10. Ello lo convierte en un observatorio privilegiado porque gran parte del estudiantado ha experimentado ambos modelos. Para realizar el estudio se analiza la evolucion del rendimiento academico en asignaturas basicas y especifica...
Within the European framework, the passive house has become an essential constructive solution in... more Within the European framework, the passive house has become an essential constructive solution in terms of building efficiency and CO2 reduction. However, the main approaches have been focused on post-occupancy surveys, measurements of actual energy consumption, life-cycle analyses in dynamic conditions, using simulation, and the estimation of the thermal comfort. Few studies have assessed the in situ performance of the building fabric of passive houses. Hence, this paper explores the applicability of non-destructive techniques—heat flux meter (HFM) and quantitative infrared thermography (QIRT)—for assessing the gap between the predicted and actual thermal transmittance of passive house façades under steady-state conditions in the Mediterranean climate. Firstly, the suitability of in situ non-destructive techniques was checked in an experimental mock-up, and, subsequently, a detached house was tested in the real built environment. The findings revealed that both Non-Destructive Test...
Buildings play a central role in the clean energy transition, which is why it is vital to underst... more Buildings play a central role in the clean energy transition, which is why it is vital to understand how energy is consumed in this sector. Energy performance certificate databases are considered a key source of information on the characteristics of built building stock. Despite a growing portfolio of studies based on information from such databases, little is known about energy consumption in offices. This paper explores the modelled energy performance of existing offices in Spain, using data from 13,701 energy performance certificates collected by the Catalan Institute of Energy (ICAEN) in 2013–2018. Offices were found to consume between 202.66 and 212.10 kWhp/m2·year and were mostly ranked in classes C and D (~64%). Offices with E, F or G labels represent ~28% of the sample while A and B energy ratings are very scarce (~8%). Key drivers of energy consumption variation were found to be the office type, construction period, climate zone, renewable energy use, energy certification p...
LCA inventory analysis for assessing the environmental impact related to the implementation of en... more LCA inventory analysis for assessing the environmental impact related to the implementation of energy retrofitting measures in representative offices, including office blocks and offices in industrial buildings and offices in residential buildings.
Abstract Considering the progressive population aging, the fact that old people spend around 90% ... more Abstract Considering the progressive population aging, the fact that old people spend around 90% of their time indoors and the high energy expenditure of heating systems, thermal comfort in nursing homes should be analysed. The aim of this study is to analyse the thermal comfort during the winter of elderly people living in nursing homes (residents) and compare it with the thermal comfort of caregivers and therapists (non-residents). Longitudinal field measurements were conducted in 25 common rooms of five nursing homes in a Mediterranean climate during the winter, from January to March 2019. Room air temperature (Ta), relative humidity (HR%), mean radiant temperature (Tr) and air velocity (va) were recorded using a Delta Ohm HD32.1 instrument with an anemometer, thermometer and a black globe thermometer. “Right-here-right-now” thermal responses of occupants were collected using a face-to-face questionnaire delivered intermittently. A total of 881 questionnaires were collected and then matched against concurrent indoor and outdoor thermal conditions. The results indicate that residents of nursing homes in the Mediterranean climate were less sensitive to variations in room temperature than therapists and caregivers, and less sensitive than found in previous studies conducted in non-elderly adults. The neutral temperature for residents was 21.6°C while for caregivers and therapists it was 21.9°C. The results also showed that clothing adaptation to the activity of caregivers would increase their thermal comfort and might help thermal adaptation to residents’ thermal needs. The modification of temperature setpoints in nursing homes based on the results of this study could influence energy use and should be carefully considered by policy makers and nursing homes’ facility managers.
Abstract In situ measurements of low thermal transmittance facades are required to ensure complia... more Abstract In situ measurements of low thermal transmittance facades are required to ensure compliance with energy performance strategies for new nearly zero-energy buildings (nZEB) and with energy policies for the transition of existing building stock to nZEB. The aim of this paper was to enhance the accuracy of the in situ measurement of low U-value facades, employing the widely used ISO 9869-1:2014 HFM method and exploring the limits of its conditions. To refine the testing conditions, three variables were analysed and compared with indications of ISO 9869-1:2014 and the existing literature: the temperature difference, the test duration and the accuracy of equipment. A continuous experimental campaign was conducted in a building mock-up. The findings showed that to accurately measure in situ low U-value facades, the temperature differences must be greater than those indicated in the existing literature. Temperature differences above 19 °C required a test duration of 72 h, while for lower temperature differences the test duration must be prolonged. The accuracy of temperature sensors had a greater impact on the accuracy of measurement in the initial cycles of the test. Likewise, the accuracy of ambient temperature sensors was found to have a considerable influence on the uncertainty of measurements.
Exceptional pandemic lockdown measures enabled singular experiments such as analysing the energy ... more Exceptional pandemic lockdown measures enabled singular experiments such as analysing the energy consumption of vacant buildings. This paper assesses the impact of the COVID-19 lockdown on the energy use of academic buildings. For this purpose, weather-adjusted energy use was compared before and during the lockdown, including different levels of lockdown restrictions. Results obtained for the 83 academic buildings of Universitat Politècnica de Catalunya-Barcelona Tech (UPC) reveal that the avoided energy consumption amounted to over 4.3 GWh during the post-pandemic year. However, the results indicate that academic buildings were still using approximately 46.9% of their typical energy consumption during strict lockdown. This revelation emphasizes the high environmental burden of buildings, regardless of whether they are occupied.
Accurate information on the actual thermal transmittance of walls is vital to select appropriate ... more Accurate information on the actual thermal transmittance of walls is vital to select appropriate energy-saving measures in existing buildings to meet the commitments of the European Green Deal. To obtain accurate results using the heat flow meter (HFM) method, good thermal contact must be made between the heat flow meter plate and the wall surface. This paper aimed to assess the influence of the non-perfect thermal contact of heat flow meter plates on the accuracy of in situ measurement of the façades’ U-value when a film was applied to avoid damage to the wall surface. Given the fact that to avoid harm to the wall surface, the laying of a film is a usual procedure in the installation of equipment during the building’s operational stage. The findings show that deviations between measured U-values when an HFM was installed directly on the wall surface and when an HFM was installed with a PVC film were found to differ significantly from the theoretical effect of including a PVC film d...
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