Mostrando recursos 1 - 11 de 11

  1. Application of computational fluid dynamics differential model coupled with human thermal comfort integral model in ventilated indoor spaces

    Conceição, E. Z. E.; Geraldo, D. R. B.; Lúcio, M. M. J. R.
    In this study the coupling of computational fluid dynamics (CFD) differential and human thermal comfort (HTC) integral numerical models is developed and used. The HTC integral numerical model evaluates the thermal comfort in non-uniform environments, while the CFD differential numerical model evaluates the airflow inside the virtual chamber and around the manikins. The numerical simulation, using upper crossed ventilation and made in winter conditions, is applied inside a virtual chamber equipped with two seated manikins, one desk and two seats. In this simulation the numerical airflow values, obtained with two different computational grid discretization with one and two manikins, are...

  2. Numerical Study of the Influence of Opaque External Trees with Pyramidal Shape on the Thermal Behaviour of a School Building in Summer Conditions

    Conceição, E. Z. E.; Lúcio, M. M. J. R.
    This paper describes a numerical study of the influence of opaque external trees with pyramidal shape on the thermal behaviour of a school building in Summer conditions. The software used simulates the thermal response of buildings with complex topology under transient conditions. This software has previously been validated by real studies both in Summer and Winter conditions. The school building considered is localised in the South of Portugal. It has three levels divided into 97 rooms or spaces, 1277 main structures and 211 windows with plain transparent glass. In the model, the building is shaded by 49 "opaque'' trees of...

  3. Airflow around a passenger seated in a bus

    Conceição, E. Z. E.; da Silva, M. C. G.; Viegas, D. X.
    The thermal comfort conditions perceived by the occupants of a bus during a typical summer are evaluated through the mapping of the flow field in the zone occupied by passengers, in terms of mean air velocity, turbulence intensity, and temperature. A full scale bus section was used in laboratory tests, with the passenger presence simulated by a thermally-regulated mannequin and the solar radiation by a panel of lamps with a spectrum similar to that of the sun. Given the symmetry of the vehicle, the only situations reproduced were those where the vehicle was subjected to radiation from the left-hand side....

  4. Evaluation of indoor air quality in classrooms equipped with cross-flow ventilation

    Conceição, E. Z. E.; Farinho, J. P.; Lúcio, M. M. J. R.
    In this work the evaluation of indoor air quality in a classroom equipped with cross-flow ventilation is presented. A numerical methodology, based on comparison with experimental data, used in the evaluation of the air exchange rate, airflow rate and the age of the air, was applied in the first phase of this work. The evolution of carbon dioxide inside spaces, with different airflow typologies, was then predicted in the second part. The study was based on a school located in the South of Portugal. In the experimental methodology the tracer gas decay method was applied. In order to reduce the...

  5. More than one insertion loss, throughout the day, for the same outdoor noise barrier

    Conceição, E. Z. E.; Rosão, V.
    ISO 10847:1997 establishes a method for determining the insertion loss of noise barriers, assuming the existence of only one insertion loss for the same outdoor noise barrier. Since during the day distinct vertical gradients of sound speed may occur, different curved path radius of the sound rays can be formed, which leads to a different insertion loss throughout the day, for the same noise barrier. This article examines the influence of atmospheric conditions on the insertion loss of noise barriers and suggests how to complement the ISO 10847:1997.

  6. Energy and thermal comfort management in a kindergarten school building in the South of Portugal in Winter conditions

    Conceição, E. Z. E.; Lopes, M. C.; Lúcio, M. M. J. R.
    In this work a numerical model, which simulates the buildings thermal response and evaluates the indoor environment comfort, in transient conditions, is used in the energy and thermal comfort management in a kindergarten school building in the South of Portugal in Winter conditions. After it's validation, this numerical model is applied in the evaluation of the building thermal behavior, using the indoor temperature field, and the occupants thermal comfort levels, using the PMV and PPD indexes. In the numerical model validation, experimental data and numerical values, for the indoor air temperature, are compared. In the experimental tests, for a typical...

  7. Thermal behaviour simulation of the passenger compartment of vehicles

    Conceição, E. Z. E.; da Silva, M. C. G.; André, J. C. S.; Viegas, D. X.
    In this work a calculus program developed with the objective of simulating the thermal behaviour in the passenger compartment of vehicles is presented. The model is based on the space-integral energy balance equations for the inside air and for the main vehicle body and surfaces. It can solve two kinds of problems. In the first one, it calculates the heat stress that the air conditioning system must equilibrate in order to satisfy predefined permanent regimen project specifications. In the second one, once imposed a particular air conditioning system and given the ambient conditions, it computes the different temperatures and heat...

  8. Performing railway traffic vibration forecast using in situ vibration measurements

    Rosão, V; César Rodrigues, C.; Conceição, E. Z. E.
    As international normalized methods for performing railway traffic vibration prediction are not available yet, the authors of this paper will analyze the feasibility and applicability of an in situ vibration measurement method in accordance with the guidelines establish in ISO 14837-1. The authors will present the achieved results of several vibration measurements, performed near the railways and the related transfer functions that will allow predicting the vibrations near different receiver locations.

  9. Human thermo-physiological sensation control based in the adaptive comfort philosophy

    Conceição, E. Z. E; Farinho, J. P.; Lúcio, M. M. J. R.
    In order to improve the building thermal efficiency, increase the human thermal comfort level and to reduce the building energy consumption, in this work, the human thermo-physiological sensation control, based in the adaptive comfort philosophy, is applied. In this control methodology the occupants, during a lesson activity, can choose among the clothing level, the activity level and the natural ventilation system. The PMV and PPD indexes are used in the numerical simulation. This work is made in a classroom school building, in the Algarve region, with Mediterranean characteristics, in Spring conditions, based in air temperature and relative humidity measurements. The...

  10. Heating, ventilating and air conditioning systems control based in the Predicted Mean Vote index

    Conceição, E. Z. E.; Lúcio, M. M. J. R.
    In this work a numerical model, which simulates the buildings thermal response and evaluates the indoor environment comfort, in transient conditions, is used in the application of Heating, Ventilating and Air Conditioning (HVAC) systems control, based in the Predicted Mean Vote (PMV) index, in the energy and thermal comfort performance in a kindergarten school building, in the South of Portugal, in Winter conditions. In the control the PMV index, based in the mean air temperature, the mean air velocity, the mean air relative humidity, the mean radiant temperature, the clothing level and the activity level, are used. In the numerical...

  11. Application of a school building thermal response numerical model in the evolution of the adaptive thermal comfort level in the mediterranean environment

    Conceição, E. Z. E.; Nunes, A. R. L.; Gomes, J. M. M.; Lúcio, M. M. J. R.
    In this paper, a review is made of the adaptive thermal comfort model This is then applied and compared with the performance of the conventional thermal comfort model for a school located in a Mediterranean weather environment Measurement data, combined with a building thermal response numerical model, are used to define the comfort performance under ambient natural ventilation and passive conditions for various classrooms These results can then be used to identify the locations that require further measures to improve comfort, such as extra passive heat load and shading measures The school design is based on that of an actual...

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