Papers by Jessica Fernández-Agüera
Frontiers in Built Environment
The research conducted under HABITA-RES explored the advisability of the integrative refurbishmen... more The research conducted under HABITA-RES explored the advisability of the integrative refurbishment of urban neighbourhoods on the outskirts of Madrid built between the end of the Civil War in 1939 and the enactment of the country’s first building code on the indoor environment in 1979. Characterised by highly inefficient buildings, many such neighbourhoods are listed as vulnerable urban areas. The study described hereunder analysed the feasibility of their conversion to energy self-sufficiency to improve residents’ environment, social circumstances and health. European directives and domestic legislation on energy production are introducing increasingly demanding requirements geared to achieving nearly zero energy buildings in 2020 and cities’ carbon neutrality by target year 2050. Possible approaches to achieve those ends were assessed under this study. The theoretical model used was validated with detailed information collected in situ on both social circumstances and energy effic...
Anexo 3 embargado por acuerdo de confidencialidad.Premio Extraordinario de Doctorado U
This study presents the methodology followed in the European R+D project ENERGYTIC “Technology, I... more This study presents the methodology followed in the European R+D project ENERGYTIC “Technology, Information and Communication Services for Engaging Social Housing Residents in Energy and Water Efficiency”. This project focused on improving energy and water consumption using ICT solutions that provide a user-friendly system for monitoring and adapting energy and water consumption. Audits, user surveys, and onsite inspections were developed to characterize 700 social housing units involved in the project. Water and energy consumption patterns were obtained through monitored data and data provided by ENDESA and EMASA (water and electricity utility companies) for the city of Malaga.
Informes de la Construcción, 2018
Este trabajo pretende realizar aportaciones de interés para reducir la brecha existente entre el ... more Este trabajo pretende realizar aportaciones de interés para reducir la brecha existente entre el comportamiento energético real y previsto en edificios. Tiene como principal objetivo establecer modelos predictivos que relacionen el consumo eléctrico de climatización para mantener unas determinadas condiciones operacionales en el ambiente interior, según sea el clima exterior, en función de la solución de fachada. Esos modelos predictivos se obtienen para módulos de ensayo en la que toda su envolvente es adiabática, a excepción de la fachada que se quiere ensayar. Tres soluciones de fachada han sido consideradas: una base que se corresponde con una solución de doble hoja de ladrillo con cámara de aire intermedia, la solución más común en viviendas plurifamiliares en España que fueron construidos entre 1940 y 1980, previamente a la primera normativa que, con carácter global, limitaba la demanda energética en los edificios; y dos soluciones de rehabilitación de la fachada anterior muy ...
Atmosphere, 2020
The indoor environment in non-university classrooms is one of the most analyzed problems in the t... more The indoor environment in non-university classrooms is one of the most analyzed problems in the thermal comfort and indoor air quality (IAQ) areas. Traditional schools in southern Europe are usually equipped with heating-only systems and naturally ventilated, but climate change processes are both progressively increasing average temperatures and lengthening the warm periods. In addition, air renewal is relayed in these buildings to uncontrolled infiltration and windows’ operation, but urban environmental pollution is exacerbating allergies and respiratory conditions among the youth population. In this way, this exposure has a significant effect on both the academic performance and the general health of the users. Thus, the analysis of the occupants’ noticed symptoms and their perception of the indoor environment is identified as a potential complementary tool to a more comprehensive indoor comfort assessment. The research presents an analysis based on environmental sensation votes, ...
Sustainability, 2019
Social housing dating from the postwar years through the end of the twentieth century is one of t... more Social housing dating from the postwar years through the end of the twentieth century is one of the major stores of European cities’ residential stock. As it is generally characterised by a poor thermal performance and an inefficient control of energy consumption, it constitutes one of the main targets for residential heritage renewal. This study aimed to locate and quantify air leaks across building envelopes in Mediterranean multifamily housing with a view to curbing the uncontrolled inflow of outdoor air that has a direct impact on occupant comfort and housing energy demand. Airtightness tests conducted in a series of protocols to quantify draught across envelope elements were supplemented with qualitative infrared thermographic and smoke tests to locate leakage pathways. Air was found to flow mainly across façade enclosures, primarily around openings, as well as through service penetrations in walls between flats and communal areas accommodating electrical and telecommunication ...
Sustainability, 2019
In southern Europe, the present stock of social housing is ventilated naturally, with practice va... more In southern Europe, the present stock of social housing is ventilated naturally, with practice varying in the different seasons of the year. In winter, windows are kept closed most of the day with the exception of short periods for ventilation, whereas the rest of the year the windows are almost permanently open. In cold weather, air changes depend primarily on the air infiltrating across the envelope and when the temperature is warm, on the air flowing in through open windows. CO2, PM2.5, and TVOC concentration patterns were gathered over a year’s time in three social housing developments in southern Europe with different airtightness conditions and analyzed to determine possible relationships between environmental parameters and occupants’ use profiles. Correlations were found between TVOC and CO2 concentrations, for human activity was identified as the primary source of indoor contaminants: peak TVOC concentrations were related to specific household activities such as cooking or ...
Buildings, 2019
A large part of the school building stock in Andalusia lacks ventilation facilities, so that the ... more A large part of the school building stock in Andalusia lacks ventilation facilities, so that the air renewal of the classrooms is achieved through the building envelope (air infiltration) or the opening of windows. This research analyses the airtightness of the classrooms in Andalusia and the evolution of CO2 concentration during school hours through in situ monitoring. Pressurization and depressurization tests were performed in 42 classrooms and CO2 concentration was measured in two different periods, winter and midseason, to study the impact of the different levels of aperture of windows. About 917 students (11–17 years of age) were surveyed on symptoms and effects on their health. The mean n50 values are about 7 h−1, whereas the average CO2 concentration values are about 1878 ppm, with 42% of the case studies displaying concentrations above 2000 ppm with windows closed.
Sustainability, 2019
A comprehensive assessment of indoor environmental conditions is performed on a representative sa... more A comprehensive assessment of indoor environmental conditions is performed on a representative sample of classrooms in schools across southern Spain (Mediterranean climate) to evaluate the thermal comfort level, thermal perception and preference, and the relationship with HVAC systems, with a comparison of seasons and personal clothing. Almost fifty classrooms were studied and around one thousand pool-surveys distributed among their occupants, aged 12 to 17. These measurements were performed during spring, autumn, and winter, considered the most representative periods of use for schools. A new proposed protocol has been developed for the collection and subsequent analysis of data, applying thermal comfort indicators and using the most frequent predictive models, rational (RTC) and adaptive (ATC), for comparison. Cooling is not provided in any of the rooms and natural ventilation is found in most of the spaces during midseasons. Despite the existence of a general heating service in a...
LEUKOS, 2019
Daylight metrics act as a useful tool to quantify the potential of natural light in an architectu... more Daylight metrics act as a useful tool to quantify the potential of natural light in an architectural space as well as the energy savings promoted by a suitable design of windows, atriums, and skylights. Accordingly, a new indoor lighting metric is proposed, minimum daylight autonomy, defined as the percentage of occupied time when an illuminance threshold can be met by daylight alone under continuous overcast sky conditions. This novel concept can determine an approximation of the maximum use of electric lighting and the quantification of minimum energy savings without the need for advanced calculation tools. Although daylight factor is the most widespread concept, it cannot forecast energy savings as accurately as dynamic metrics. In addition, daylight autonomy is the most usual dynamic definition, because it estimates the energy consumption of on-off electric lighting systems depending on weather conditions. However, there is no link between static and dynamic metrics, because both concepts are based on different variables. This research proposes the calculation procedure for minimum daylight autonomy, as well as the equations that serve to predict dynamic metrics based on static metrics, after confirming the accuracy of the simulation program that calculates the metrics using a test cell under real conditions.
Energies, 2019
Spain’s high winter weather-associated death count, the second largest in Europe, can be attribut... more Spain’s high winter weather-associated death count, the second largest in Europe, can be attributed primarily to the low construction standards of its social housing, particularly the stock built prior to the entry into effect of the earliest statutory provisions on envelope quality. Hence, improving building envelopes to both reduce energy consumption and raise occupant comfort levels is important. Air leakage is one of the factors with the greatest impact on indoor comfort and domestic energy consumption. This study explores the sensitivity of energy consumption to that parameter in a series of types of social housing built between 1950 and 1979 in five Mediterranean climate zones. Demand in a total of 53 housing units located in 21 developments was simulated to that end. The findings show that air permeability has a significant effect on wintertime demand in the sample studied. Although the impact is greater in the more severe climates where it is estimated to be over 10 kWh/m2, ...
International Journal of Engineering and Technology, 2019
The circadian rhythms, endogenous cycles that repeat almost every 24 hours, must be synchronized ... more The circadian rhythms, endogenous cycles that repeat almost every 24 hours, must be synchronized by daylight stimuli, particularly due to its short wavelength fraction. In this way, insufficient exposure to daylight or its spectral equivalent in electric lighting can endanger human health. The main aim of this research is to develop a methodology in which circadian stimulus (CS) values can assist to the choice of an office window design, in order to promote a good circadian rhythm and to benefit human health and well-being. A room model located in Madrid is presented as a study case, having different variables such as the window measures or the environment reflectance values. It is concluded from the results of this study case that CS and SPD are highly conditioned by the indoor environment reflectance and therefore, also affects to the minimum window size.
International Journal of Engineering and Technology, 2019
Light is the main variable which affects to the circadian rhythm, promoting up to 70% of the mela... more Light is the main variable which affects to the circadian rhythm, promoting up to 70% of the melatonin suppression. In comparison with the visual system, the circadian system requires more light to be activated and is more sensitive to blue light. As can be deduced, daylighting represents an ideal light source for circadian entrainment. Architectural and design features, such as window size and room reflectance, impact the amount of circadian stimulus that occupants will receive. This study aims to quantify the circadian stimulus promoted in classrooms, according to the window size and reflectance of the surfaces. A first trial is carried out, monitoring the spectral power distribution perceived by the eyes of the students according to different orientations and observer's positions. Secondly, several simulations are developed, using the daylight simulation program DaySim 3.1 and defining a classroom model with a variable window size and reflectance. The results show the noticeable impact of the reflectance of the inner surfaces in the circadian stimulus calculation, as well as the effect of the window size.
Sustainability, 2018
Although energy analysis techniques can contribute to substantial energy savings in housing stock... more Although energy analysis techniques can contribute to substantial energy savings in housing stock retrofitting operations, the outcomes often deviate significantly from the predicted results, which tend to overestimate potential savings by overestimating the starting energy baselines, particularly in southern Europe. This deviation can be largely attributed to occupant practice relating to the use of air conditioning facilities and the temperatures at which occupants feel comfortable. The patterns observed differed widely from standard values. In this study environmental variables, primarily indoor air temperature both with and without HVAC, were monitored in occupied dwellings for a full year. The data gathered were supplemented with surveys on occupants’ temperature-related behaviour to define comfort patterns. The findings show that the standards in place are not consistent with actual comfort-accepted patterns in medium- to low-income housing in southern Spain, where energy cons...
Energies, 2018
Air leakage and its impact on the energy performance of dwellings has been broadly studied in cou... more Air leakage and its impact on the energy performance of dwellings has been broadly studied in countries with cold climates in Europe, US, and Canada. However, there is a lack of knowledge in this field in Mediterranean countries. Current Spanish building regulations establish ventilation rates based on ideal airtight envelopes, causing problems of over-ventilation and substantial energy losses. The aim of this paper is to develop a methodology that allows the characterization of the envelope of the housing stock in Spain in order to adjust ventilation rates taking into consideration air leakage. A methodology that is easily applicable to other countries that consider studying the airtightness of the envelope and its energetic behaviour improvement is proposed. A statistical sampling method has been established to determine the dwellings to be tested, considering relevant variables concerning airtightness: climate zone, year of construction, and typology. The air leakage rate is dete...
Current standards for indoor air quality (IAQ) in non-residential buildings demand high air renew... more Current standards for indoor air quality (IAQ) in non-residential buildings demand high air renewal rates with different filtration stages and constant flow. Currently, new school buildings must incorporate mechanical ventilation systems which modify traditional heating installations in order to comply with the requirements for indoor air quality and energy efficiency. This study analyses the technical and energy outcomes involved in a school building when changing from a traditional central heating system with radiators, to an HV system which fulfils the current regulatory framework.
Informes de la Construcción, 2014
This work is part of a major investigation the authors are undertaking aiming to evaluate the ene... more This work is part of a major investigation the authors are undertaking aiming to evaluate the energy performance of different retrofitting strategies for housing buildings, in order to establish preferential criteria of intervention according to its climate zone location, morphology, constructive features and patrimonial values. In the historic centre of Oporto, one of the major actions resides on a significant reduction in the heating loads of these distinctive buildings by decreasing the windows infiltration rate. To be able to accurate this potential for energy savings, in situ measurements of the infiltration rate of this houses at present were required, previous to a possible intervention. This article presents the data obtained using a fan pressurization method in two non-refurbished characteristic buildings of the Oporto's Historic Centre, and analyses the results obtained for both a typical sash window and a casement window. Some relations between these infiltration rates and the buildings morphological and typological characteristics are considered.
Buildings, 2011
Much of the residential sector in Spain is obsolete, with inadequate conditions of comfort and hi... more Much of the residential sector in Spain is obsolete, with inadequate conditions of comfort and high energy consumption. For this reason most of the potential for improving energy efficiency lies in the existing residential sector, which requires upgrading to meet the quantitative and qualitative changes required at present. This study of specific cases aimed at establishing general criteria for action has been prompted by the difficulty in proposing general intervention strategies. This paper presents a case study for the energy retrofit of 68 social housing units in Cordoba (Spain) evaluating their energy consumption, with a view to improving the building's energy balance and indoor thermal comfort, on which user comfort depends.
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Papers by Jessica Fernández-Agüera