The need to study air leakages: case study in social housing of Zabalgana development (Vitoria)

[Resumen] La diferencia entre ventilación e infiltraciones parece clara: la primera hace referencia a una entrada controlada de aire a través de las aberturas, y la segunda a una entrada caótica a través de los intersticios de la envolvente arquitectónica, y que depende de las condiciones exteriores de viento y temperatura. Pero la normativa española no hace mención de esta realidad, excepto en las carpinterías, de manera que el caudal de ventilación necesario se hace sobre modelos de cerramientos estancos, con la consecuencia que las infiltraciones provoquen problemas de sobreventilación, corrientes de aire y descontrol de la calidad del aire interior.[Abstract] The difference between ventilation and air leakages seems clear: ventilation refers to a controlled air inlet through openings, meanwhile air leakages cause a chaotic inlet across gaps of the building enclosure, which depends on external conditions of wind and temperature. But the Spanish Building Code makes no mention to this reality, except in frames, so ventilation is calculated over perfect airtighted models; it brings as a consequence that the air leakages cause problems of over-ventilation, drafts and a lack of control on IAQ

The heart of the Villages of Colonization

[Resumen] Los centros de los pueblos levantados por el INC en los años cincuenta y sesenta en España, son uno de los mejores casos donde estudiar la evolución que la arquitectura y el urbanismo de nuestro país estaban experimentando, libres ya del imposible problema sobre el “estilo español”. Fueron el banco de pruebas donde ensayar criterios de diseño más libres y orgánicos, trazados espacialmente más flexibles y articulados entre sí, consecuentes con la historia y el lugar, dimensionados según la medida humana y potenciando la relación recíproca entre sus habitantes... Lugares que, con el transcurso de los años, dibujaron la modernidad.[Abstract] The village centers raised by the INC in the fifties and sixties in Spain, are one of the best cases in which study the evolution that the architecture and the city planning of our country were experiencing, freed from the impossible problem of the “Spanish style”. They were the testing bench in which were tested free and organic designs, more flexible and articulated sketches, consistent with the history and place, sized according to the human measure and enhancing the reciprocal report between its inhabitants... Places that, over the years, drew the modernity

Influencia de la ubicación de las aberturas en la eficiencia de la ventilación en viviendas

Building ventilation implies managing the “clean” air and extracting the contaminated air through the walls, distributing and circulating the incoming air and preventing the contamination of the indoor air. The Spanish Technical Building Code, in his section HS3 – IAQ, usually set up minimum ventilation flow rates according to its typology, surface, possible contamination sources or the number of occupants, without thinking over the path of the air from the inlet to the exhaust point. For that reason, even if such standards are met within the spaces of the home, there may still be areas in the interior that suffer an excess or deficit of ventilation. The present study aims to overcome the purely quantitative performance of DBHS3, to control qualitatively the air renewal throughout the living space; this allows even to reduce the volumetric flow rate with the consequent energetic saving.El proceso de ventilación incluye impulsar aire “limpio” y extraer el viciado a través de los cerramientos, distribuir y hacer circular el aire entrante y prevenir la contaminación interior. El Código Técnico de la Edificación, en su Sección HS3 – Calidad del Aire Interior, establece unos caudales mínimos de ventilación generalistas a cumplir en viviendas en función de su tipología, superficie, posibles fuentes contaminantes y número de ocupantes, sin considerar la trayectoria del aire desde su admisión hasta su extracción. Por dicha razón ocurre el hecho que, aunque se cumpla la Normativa en cuanto al recinto a ventilar, pueden existir zonas en el interior que presenten exceso o déficit de ventilación. El estudio que se presenta tiene como objetivo superar el cumplimiento meramente cuantitativo del DB-HS3, para controlar cualitativamente la renovación del aire en todo el espacio habitable, lo que permite incluso reducir el caudal con el consiguiente ahorro energético

Methodology applied to the evaluation of natural ventilation in residential building retrofits: A case study

Producción CientíficaThe primary objective of this paper is to present the use of a steady model that is able to qualify and quantify available natural ventilation flows applied to the energy retrofitting of urban residential districts. In terms of air quality, natural ventilation presents more efficient solutions compared to active systems. This method combines numeric simulations, through the utilization of Ansys Fluent R15.0® and Engineering Equation Solver EES®, with on-site pressurization tests. Testing consists of the application of the seasonal pressure gradient on the building’s envelope and the calculation of the ventilation flows in three climatic representative conditions (summer, winter, and annual average). Through the implementation of this methodology to existing buildings it is possible to evaluate the influence of the built environment, as well as key parameters (relative height of the dwelling, number of vertical ventilation ducts, and airtightness of windows) of available natural ventilation.CITyFiED project, which has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration activities under the Grant Agreement number 60912

An evaluation framework to support optimisation of scenarios for energy efficient retrofitting of buildings at the district level

Producción CientíficaEnergy-efficient retrofitting of buildings has become essential to achieve the environmental objectives of the European Union’s (EU) strategies towards reducing carbon emissions and energy dependency on fossil fuels. When tackling retrofitting projects, the issue of scale becomes essential as sometimes this can determine the sustainability of the project. Therefore, a comprehensive approach is essential to ensure effective decision-making. A platform has been designed within the EU funded OptEEmAL project to support stakeholders in this process, providing functionalities that can automatically model and evaluate candidate retrofitting alternatives considering their priorities, targets and boundary conditions. A core element of this platform is the evaluation framework deployed which implements a multi-criteria decision-making approach to transform the priorities of stakeholders into quantifiable weights used to compare the alternatives. As a result, more informed decisions can be made by the stakeholders through a comprehensive evaluation of the candidate retrofitting scenarios. This paper presents the approach followed to develop and integrate this evaluation framework within the platform as well as its validation in a controlled environment to ensure its effectiveness

Integration of prioritisation criteria in the design of energy efficient retrofitting projects at district scale: A case study

Producción CientíficaThe evident need for improving the existing building stock still suffers from important barriers, such as the fragmentation of the value chain, the lack of information regarding some solutions, and the lack of confidence with respect to energy savings, which prevent unlocking investments, and the difficult communication among stakeholders. Therefore, new processes based on exploiting the potential of existing and new tools are required. In this framework, the OptEEmAL project has developed a tool that integrates stakeholders, data and tools in order to ease the process of designing energy efficient retrofitting projects at building and district scale. This tool works around an optimisation framework in order to evaluate, compare and optimise candidate retrofitting scenarios against a set of indicators showing the performance of the district. This evaluation and optimisation method is based on aggregating indicators through transforming the priorities of stakeholders into a mathematical weighting scheme, which makes it possible to provide scenarios within their expectations. Therefore, the generation of these scenarios is driven by their design parameters, being thus flexible and adapted to their needs. This paper shows the implementation of this tool and specifically 3 different prioritisation schemes, analysing how they impact into the decision making process and selection of the retrofitting strategy

A graphical tool to estimate the air change efficiency in rooms with heat recovery systems

Producción CientíficaIndoor air quality in buildings must be guaranteed for the health and comfort of the occupants. In order to assess the ventilation strategy of a considered room, the parameter of the air change efficiency ( εa ) can be used. The objective of this work is to provide designers with a graphical tool for a reliable estimate of the value of εa of a room. The temperature gradient between the outdoor air supply and the indoor air is so low that the ventilation flow can be assumed as isothermal when high-efficiency heat recovery systems are used. By means of charts, the optimal location of the openings for a better εa can be determined during the design process, in order to subsequently apply them. It is concluded that it is very important to consider the εa in the case of openings located in facing walls given that its range varies between 40% and 65%. In contrast, its use can be obviated in the case of openings located in non-facing walls, as the value of εa obtained is close to 50%; this means a perfect mixing air flow pattern, which is the reference value for the estimation of the indoor air quality (IAQ) in the different national regulations.EPACRA: Lanzadera project (TCUE.6-LANZADERA 067/157541

Energy impact of the air infiltration in residential buildings in the Mediterranean area of Spain and the Canary islands

Air infiltration through the building envelope has already been proven to have a significant energy impact in dwellings. Different studies have been carried out in Europe, but there is still a lack of knowledge in this field regarding mild climates. An experimental field study has been carried out in the Mediterranean climate area of Spain and the Canary Islands in order to assess the air permeability of the building envelope and its energy impact. A wide characterization and Blower Door tests have been performed in 225 cases in Alicante, Barcelona, Málaga, Sevilla and Las Palmas de Gran Canaria for this purpose. The obtained mean air permeability rate for the 225 studied cases was 6.56 m3/(h·m2). The influence of several variables on airtightness was statistically analysed, although only location, climate zone and window material were found to be significant. Air infiltration has an energy impact between 2.43 and 16.44 kWh/m2·year on the heating demand and between 0.54 and 3.06 kWh/m2·year on the cooling demand.This work was supported by the Spanish Ministry of Economy and Competitiveness (BIA2015-64321-R) under the research project INFILES: Repercusión energética de la permeabilidad al aire de los edificios residenciales en España: estudio y caracterización de sus infiltraciones

Methodology for the Study of the Envelope Airtightness of Residential Buildings in Spain: A Case Study

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 determined using a standardized building pressurization technique according to European Standard EN 13829. A representative case study has been presented as an example of the implementation of the designed methodology and results are compared to preliminary values obtained from the database