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

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

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