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- Application of an indoor greenhouse in the energy and thermal comfort performance in a kindergarten school building in the South of Portugal in winter conditionsPublication . Conceição, E. Z. E.; Lucio, M. M. J. R.; Lopes, M. C.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 an indoor greenhouse in the energy and thermal comfort performance in a kindergarten school building, in the South of Portugal, in Winter conditions. In the numerical simulation of the kindergarten school building, the 25 compartments, the 498 building main bodies and the 42 windows glasses, as well as two schools and three residential surrounding main buildings, are considered. This numerical model is applied in the evaluation of the kindergarten thermal behavior, using the indoor temperature field, and the occupants thermal comfort levels, using the PMV and PPD indexes. After to be compared the numerical and experimental indoor air temperatures field and identified the indoor thermal uncomfortable spaces, the numerical model is used in the evaluation of the indoor greenhouse performance, in order to increase the indoor air temperature and thermal comfort levels, using solar renewable energy, without increase of the kindergarten energy consumption. It is analyzed in detail the greenhouse ventilation operating time and the warm airflow transport way, using an internal ducts system or a corridor space, from the greenhouse to the indoor coldest spaces.
- Development of a temperature control model used in HVAC systems in school spaces in Mediterranean climatePublication . Conceição, Eusébio; Lúcio, Maria Manuela Jacinto do Rosário; Ruano, Antonio; Crispim, E. M.In this paper a temperature control model used in heating, Ventilating and air-conditioning (HVAC) systems in school spaces, in Mediterranean climate, is developed. This empirical model considers the indoor preferred environmental temperature, the outdoor environmental temperature and the adaptation to the seasons of the year and to the spaces. In the development of the empirical model, in a school building located in the Algarve region, in the South of Portugal, occupied spaces by the non-teacher staff (administrative and auxiliary), teachers and students were used. In these spaces, equipped with heating, ventilating and air-conditioning systems, the occupants can change, during one year of school activities, the indoor environmental conditions in order to obtain acceptable comfort conditions. The indoor air temperature and relative humidity inside four spaces, namely an office room, a secretary room, a teachers room and a library room, the outdoor air temperature and other parameters related to the spaces and heating, ventilating and air-conditioning systems were measured every minute during one year. This empirical model, based in a group of equations for different months and for several spaces, gives information that can be used in the control of a heating, ventilating and air-conditioning systems, in school spaces, in Mediterranean climate, in order to promote indoor acceptable conditions with energy savings. In this model the adaptation to the outdoor environment, for different seasons, the clothing level and the fact that occupants enter and leave frequently from spaces equipped with heating, ventilating and air-conditioning systems to others not equipped are analyzed.
- Evaluation of thermal comfort in slightly warm ventilated spaces in nonuniform environmentsPublication . Conceição, E. Z. E.; Lúcio, Maria Manuela Jacinto do Rosário; Lourenço, T. M. C.; Brito, A. I. P. V.The present work analyzes and evaluates the global thermal comfort and local thermal discomfort levels of an occupant subjected to a symmetric nonuniform airflow, originated in common use ventilators. Several incident airflow directions are studied and their effects are described. The global thermal comfort level is evaluated through a multi-nodal numerical model that simulates human and clothing thermal responses, while the local thermal discomfort level is analyzed using an empirical model that predicts draft risks. The computational model of the human body and clothing thermal systems is based on the energy balance integral equations for human body tissue, blood, and clothing, as well as mass balance integral equations for the blood and transpired water in skin surface and the clothing. The human body is divided into 35 elements, each one in several layers of tissue, which could be protected through some clothing layers. A thermoregulatory system model was adapted to control the human body tissue temperature. The experimental tests were carried out in a test chamber in controlled environmental conditions; a thermal manikin was used to simulate the human posture, an indoor climate analyzer was used to measure the environmental variables around the occupant, and two ventilators were used to produce an airflow field around the occupant. The frontal and ascendant airflows from the ventilators placed in front of the occupant are characterized and their velocities around the occupant are measured for several incident angles. The global thermal comfort conditions of the occupant are evaluated both with and without ventilation, and the local thermal discomfort level is evaluated with ventilation for slightly warm, moderate environments.
- Energy and thermal comfort evaluation for different passive solutions in a kindergarten in summer conditionsPublication . Conceição, E. Z. E.; Lopes, M. C.; Lucio, M. M. J. R.In this work a numerical model, which simulates the buildings thermal response with complex topology and evaluates the indoor environment comfort, in transient conditions, is used in the energy and thermal comfort evaluation for different passive solutions in a kindergarten, in Summer conditions. After the validation phase, this numerical model is applied in the evaluation of the building thermal behaviour, using the indoor temperature field, and the occupants' thermal comfort levels, using the PMV and PPD indexes. The introduction of a roof placed in the top of the kindergarten, horizontal shading devices placed above the windows level facing South and external pyramidal opaque trees placed in front to the windows facing West and East, used to reduce the indoor temperature level and to increase the indoor thermal comfort level, in Summer conditions, are analyzed.
- Numerical Study of the Thermal Efficiency of a School Building with Complex Topology for Different OrientationsPublication . Conceição, E. Z. E.; Lúcio, Maria Manuela Jacinto do RosárioIn this work a numerical model that simulates the thermal behavior of a building with complex topology and evaluates the indoor thermal and air quality, in transient conditions, is used for a school building thermal project. The program calculates the building surfaces solar radiation field, the building's temperatures, the internal environmental variables, and the occupant's comfort levels. Initially, after the numerical model is validated, the software is used to evaluate the school building's thermal response for four different orientations, either in winter or summer conditions. The work then aims to identify uncomfortable spaces in order to propose, as an example, several solutions that could be introduced for each orientation, that would improve the thermal comfort and air quality levels to which the occupants are subjected, and decrease the building's energy consumption levels. The information obtained from this study could be used to help a designer choose which thermal systems and solutions function best for a preferred school building orientation.
- Prediction of building's temperature using neural networks modelsPublication . Ruano, Antonio; Crispim, E. M.; Conceição, Eusébio; Lúcio, Maria Manuela Jacinto do RosárioThe use of artificial neural networks in various applications related with energy management in buildings has been increasing significantly over the recent years. In this paper the design of inside air temperature predictive neural network models, to be used for predictive control of airconditioned systems, is discussed. The use of multi-objective genetic algorithms for designing off-line radial basis function neural network models is detailed. The performance of these data-driven models is compared, favourably, with a multi-node physically based model. Climate and environmental data from a secondary school located in the south of Portugal, collected by a remote data acquisition system, are used to generate the models. By using a sliding window adaptive methodology, the good results obtained off-line are extended throughout the whole year. The use of long-range predictive models for airconditioning systems control is demonstrated, in simulations, achieving a good temperature regulation with important energy savings.
- Air quality inside a school building: air exchange monitoring, evolution of carbon dioxide and assessment of ventilation strategiesPublication . Conceição, E. Z. E.; Lucio, M. M. J. R.This paper presents an assessment of indoor air quality and various ventilation strategies inside a school building located in the south of Portugal. In the first phase, ventilation rate was experimentally evaluated using the tracer gas method. In the second part, different airflow typologies were investigated and, after calculating the air exchange and flow rates for each of them, the evolution of metabolic carbon dioxide inside the spaces was numerically estimated. Ventilation measurements were made in classrooms, auditorium, offices, staff and computer rooms. The assessment of ventilation was based on evaluating the carbon dioxide produced by the occupants for three ventilation approaches; these were: one based on cross-flow natural ventilation (in current use) and two based on forced ventilation systems. In the case of the forced systems, one was based on providing a constant flow to meet the required Portuguese ventilation standard in the main occupied rooms while the other was an adjusted constant rate based on a simple calculation procedure that took into consideration the air quality needs of all the spaces including corridors and atria. This approach was developed to produce an efficient yet inexpensive ventilation approach that did not incorporate expensive sensors and control systems. Carbon dioxide evolution predictions were made using software that evaluated the thermal response and the air quality of a building with complex topology. The numerical model used to evaluate air quality, was based on mass conservation integral equations in which the final equations system was solved through the Runge-Kutta-Fehlberg method with error control. A statistical study of the occupation cycle in the school building during the day was developed.
- Thermal behaviour simulation of the passenger compartment of vehiclesPublication . 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 fluxes, either in transient or steady regimens. The validation of this model was done with a railway car, in a summer situation, when it was immobilized and running. The model reproduced well the experimentally determined temperature and heat flux evolutions. However, the numeric simulation showed best agreement with the experimental results when used with the convection heat transfer coefficients, determined experimentally in this work.
- Evaluation of local thermal discomfort in a classroom equipped with cross flow ventilationPublication . Conceição, E. Z. E.; Lucio, M. M. J. R.; Vicente, V. D. S. R.; Rosão, VitorThis paper presents an evaluation of the local thermal discomfort level in a classroom equipped with cross ventilation, for a typical moderate summer day in Portugal. Three different ventilation configurations based on window and door opening were considered. In each, the thermal comfort, air quality and acoustical comfort conditions were also evaluated. This experimental study was made in the South of Portugal, exposed to a Mediterranean climate. Thermal comfort was based on the PMV index, the air quality was based on the air renovation rate and acoustical comfort levels were based on the reverberation time, voice clarity, definition and early reflection ratio. The detailed local thermal discomfort analysis was based on draught risk and uncomfortable air velocity fluctuations. Other measurements included relative humidity, the radiative mean temperature, carbon dioxide concentration (tracer gas decay), and noise level decay of impulsive response. Results showed that for the warmest of weather open windows and classroom door gave the best air quality and comfort conditions.
- Airflow inside school building office compartments with moderate environmentsPublication . Conceição, E. Z. E.; Vicente, V. D. S. R.; Lucio, M. M. J. R.In this paper, the airflow inside school building office compartments with moderate environments, in steady-state conditions, is experimentally and numerically analyzed. The experimental tests are made in a developed experimental chamber, while the numerical results are obtained in a developed numerical model. The air velocity fluctuations are experimentally measured and the air velocity root mean square, the air turbulence intensity, the draft risk, the air velocity fluctuation frequencies, and the air velocity fluctuation equivalent frequencies are calculated. The mean and local air renovation rates, using the decay tracer gases method with a carbon dioxide concentration, are calculated. The three-dimensional air velocity and the air renovation rate are numerically calculated. Both these experimental and numerical results are compared to better understand the airflow topology inside this kind of compartment and evaluate the comfort level, namely the thermal comfort, local thermal discomfort, and air quality levels, to which occupants are subjected. The analyzed airflow topology, with the air forced inlet and outlet located above the occupants' head level, is divided into two areas: the non-occupied upper area, which contains the airflow inlet and outlet, with high air velocity levels, is developed to facilitate the contaminant extraction released by the occupants, while the occupied lower area, with low air velocity levels, is developed to ensure good thermal comfort and reduced local discomfort levels, with the capacity to transport the occupants' contaminants to the upper area.