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Departamento de Engenharia Civil (DEC)

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Browsing Departamento de Engenharia Civil (DEC) by Subject "ACH"

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  • Air Change Rates in Multi-Family Residential Buildings in Northern Portugal
    Publication . Pinto, Manuel; Boman, Carl-Axel; Stymne, Hans; Freitas, Vasco
    Existing technical recommendations and standards regarding natural ventilation in Portugal establish one air change rate, ACH, in main rooms (bedrooms and living rooms) and four ACH in service rooms (kitchens and bathrooms). Admittedly these rates are not being observed in most residential buildings recently erected in Portugal. Two trials (May 2002 and January 2003, lasting approximately 2 weeks each) were carried out for the purpose of estimating the implementation of the rates in a two-bedroom flat which is inhabited and equipped with a ‘mixed’ ventilation system: intake via self-adjusting ventilation inlets in the living room and bedrooms, natural exhaust in the bathroom assisted by discontinuous mechanical extraction in the kitchen. Some conclusions can be drawn regarding the efficiency of the ventilation system used, namely the results of the study shows that the measured ventilation rate was irregular and lower than the Portuguese recommendations during both seasons.
    2003-12-07Journal article Open access Show more
  • Mixed Ventilation Systems in Residential Buildings: Application of the design Principles Based on prNP 1037-5
    Publication . Pinto, Manuel; Viegas, João; Freitas, Vasco
    In multi-family buildings in Portugal essentially mixed ventilation systems are used. However, this system does not currently have a document that supports its design. The mixed ventilation system envisaged in the prNP 1037-5 considers two situations a) base flowrate given by passive devices which will allow the dwelling to be swept by flow rates due to wind action (e.g. horizontal ducts between compartments located on opposite facades), b) peak flowrate given by mechanical extraction placed in service compartments (kitchen and toilet facilities). In this paper, through a simulation using the CONTAM software and based on experimental data of air permeability of ventilation devices, an application of the design principles of the mixed ventilation systems idealized in prNP 1037-5 is performed. A sensitivity analysis is carried out by varying some of the most significant parameters in mixed ventilation systems, such as: geographical location, orientation and elevation of the dwellings; positioning of interior doors, closed or open. It involves the annual simulation of air flows using representative environmental conditions of the continental Portuguese climate (four cities), and the production of indoor pollutants (water vapor and CO2). Through this simulation we intend to conclude, for example, what is proper condition (opened or closed) of interior doors and the recommended air intake flows.
    2016-09Journal article Open access Show more