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

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 simulation of the kindergarten, 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

Cartas para Almeida Garrett : lembranças do exílio

The purpose of this paper is to analyse and presente private letters received by the writer João Baptista de Almeida Garrett in the period in wich he was in exile. They are a set of 25 letters, aproximately, written by his mother, Family and friends in a troubled momento of the history of Portugal. I chose three moments of Garrett’s exile. The first occured between the years 1823 and 1826, it was a time of crises, where the most radical liberals are fleeing and secret societes are dissolved, The second occured between the years of 1828 and 1832, because of the return of D. Miguel to Portugal and the probable political hardening against the liberals. The third, wich I classify as «exile», but had diferente characteristics from the others, occured between the year of 1834 and 1836. In that period Garrett was removed from Portugal, wich was devastated by a civil war, under the pretext of composing a diplomatic mission. All the letters chosen are part of the literary collection located in the reserved sector of the University Library of Coimbra

Cartas para Almeida Garrett : lembranças do exílio

A proposta deste trabalho é analisar e apresentar cartas privadas recebidas pelo escritor João Baptista de Almeida Garrett no período em que esteve no «exilio». São um conjunto de 25 cartas, aproximadamente, escritas por sua mãe e familiares num momento conturbado da história de Portugal. Escolhi três momentos de «exílio» de Garrett. O primeiro ocorreu entre os anos de 1823 e 1826, foi um momento de crise, onde os liberais mais radicais põem-se em fuga e as sociedades secretas são dissolvidas. O segundo ocorreu entre os anos de 1828 e 1832, por causa do retorno de D. Miguel a Portugal e o provável endurecimento político contra os liberais. O terceiro, que classifico como «exílio», mas teve características diferentes das demais, ocorreu entre os anos de 1834 e 1836. Nesse período Garrett foi afastado de Portugal, que estava devastado por uma guerra civil, com o pretexto de compor uma missão diplomática. Todas as cartas escolhidas fazem parte do espólio literário localizado no setor de reservados da Biblioteca da Universidade de Coimbra

Almeida Garrett: diálogos da ficção com o jornalismo

A proposta deste artigo é apresentar a recepção dos romances Viagens na minha terra e O arco de Sant'Ana na imprensa portuguesa da época. Os artigos que foram selecionados em jornais a respeito destas obras compreendem o período de 1843-1851. Estes anos foram de verdadeira instabilidade política e marcaram o início do constitucionalismo em Portugal (1834-1851). Neste período, Garrett publica Viagens na minha terra (1843 - 1845 - 1846) e O arco de Sant'Anna (1845-1851), obras em que suas idéias políticas serão discutidas com complexidade e os rumos do liberalismo serão postos sobre a mesa.

Application of horizontal confluents jets in a school virtual chamber

The study presented in this work is performed in a virtual chamber, similar to an existing experimental chamber, with dimensions of 4.50×2.55×2.50 m3. The chamber, occupied with twelve virtual manikins, is equipped with six tables, twelve chairs, one exhaust system and one inlet system, based in confluents jets system. In the exhaust system are considered six air ducts, located above the head level, connected to the ceiling area. The inlet system, based in four vertical ducts, with 0.15 m diameter, located on the corners of the chamber, are equipped with consecutive holes, that promotes horizontal jets near the wall. The results demonstrate that when the airflow rate increases the air quality number increases, the thermal comfort number decreases and the ADI increases slightly. The predicted percentage of dissatisfied index values show that the thermal comfort level is acceptable, the dioxide carbon concentration values show that the indoor air quality is near the acceptable value and the Draught Risk is acceptableSAICT-ALG/39586/2018 (CRESC Algarve 2020)info:eu-repo/semantics/publishedVersio

Energy production in solar collectors in a university building used to improve the internal thermal conditions in winter conditions

In this numerical study the energy production in solar collectors in a University building used to improve the internal thermal conditions is made. Passive and active solutions, using external solar collector and internal thermo-convectors, are used. The numerical simulation, in transient conditions, is done for a winter typical day with clean sky. This numerical study was carried out using a software that simulates the Building Dynamic Response with complex topology in transient conditions. The software evaluates the human thermal comfort and indoor air quality levels that the occupants are subjected, Heated Ventilation and Air Conditioned energy consumption, indoor thermal variables and other parameters. The university building has 107 compartments and is located in a Mediterranean-type environment. External solar water collectors, placed above the building’s roof, and internal thermo-convectors of water/air type, using mixing ventilation, are used as passive and active strategies, respectively. The thermal comfort level, using the Predicted Mean Vote index, and the indoor air quality, using the carbon dioxide concentration, are evaluated. The results show that in winter conditions the solar collectors improve the thermal comfort conditions of the occupants. The indoor air quality, in all ventilated spaces, is also guaranteed.SAICT-ALG/39586/2018info:eu-repo/semantics/publishedVersio

Development of a double Skin Facade system applied in a virtual occupied chamber

In this study a system constituted by seven double skin facades (DSF), three equipped with venetian blinds and four not equipped with venetian blinds, applied in a virtual chamber, is developed. The project will be carried out in winter conditions, using a numerical model, in transient conditions, and based on energy and mass balance linear integral equations. The energy balance linear integral equations are used to calculate the air temperature inside the DSF and the virtual chamber, the temperature on the venetian blind, the temperature on the inner and outer glass, and the temperature distribution in the surrounding structure of the DSF and virtual chamber. These equations consider the convection, conduction, and radiation phenomena. The heat transfer by convection is calculated by natural, forced, and mixed convection, with dimensionless coefficients. In the radiative exchanges, the incident solar radiation, the absorbed solar radiation, and the transmitted solar radiation are considered. The mass balance linear integral equations are used to calculate the water mass concentration and the contaminants mass concentration. These equations consider the convection and the diffusion phenomena. In this numerical work seven cases studies and three occupation levels are simulated. In each case the influence of the ventilation airflow and the occupation level is analyzed. The total number of thermal and indoor air quality uncomfortable hours are used to evaluate the DSF performance. In accordance with the obtained results, in general, the indoor air quality is acceptable; however, when the number of occupants in the virtual chamber increases, the Predicted Mean Vote index value increases. When the airflow rate increases the total of Uncomfortable Hours decreases and, after a certain value of the airflow rate, it increases. The airflow rate associated with the minimum value of total Uncomfortable Hours increases when the number of occupants increases. The energy production decreases when the airflow increases and the production of energy is higher in DSF with venetian blinds system than in DSF without venetian blinds system.SAICT-ALG/39586/2018, CRESC Algarve 2020info:eu-repo/semantics/publishedVersio

Production of thermal energy in university building greenhouses in cold climate conditions

The present work focuses on the production of thermal energy in University building greenhouses in cold climate conditions. The building model uses a system of energy and mass balance integral equations, which are solved by the Runge–Kutta–Felberg method with error control. This numerical study is about the thermal behaviour of a university building with complex topology, in winter and transient conditions. The thermal comfort of the occupants, using the Predicted Mean Vote index, and the indoor air quality, using the carbon dioxide concentration, are evaluated. This building has 319 compartments distributed by four floors and it is equipped with one internal greenhouse in the third floor. This greenhouse is located on the south facing facade and the heated air in this space will be transported to compartments located on the north facing façade. The spaces subject to the influence of the heated air coming from the greenhouse improve the level of thermal comfort of its occupants. The level of indoor air quality in occupied spaces is acceptable according to international standards.SAICT-ALG/39586/2018; (CRESC Algarve 2020)info:eu-repo/semantics/publishedVersio

Application of semi-circular double-skin facades in auditoriums in winter conditions

The DSF (double-skin facade) system is an important element in building design and is used in adjacent spaces to control the inlet solar radiation, heat the air, reduce energy consumption, decrease the acoustics levels, and produce photovoltaic energy, among other improvements. The DSF system can, for example, be used in winter conditions to heat the air, which is then transported to non-adjacent spaces to improve the thermal comfort level and the indoor air quality that the occupants are subjected to. Smooth DSF systems, which are a focus in the literature, are subjected to higher solar radiation levels at a specific hour of the day. The semi-circular DSF system used in this work, which was built from a group of smooth DSF systems with different orientations, guarantees the reception of the highest incident solar radiation throughout the entire day. This work presents a numerical study of a new DSF system, called the semi-circular DSF. The DSF system consists of a set of 25 smooth DSFs with different orientations, each one consisting of an outer glazed surface and an inner surface provided by the outer facade of the auditorium, both separated by an air channel. In this work, the influence of the radius of the semi-circular DSF system and the opening angle of the DSF system on the thermal response of the auditorium was analysed. Thus, six auditoriums were considered: two sets of three auditoriums with radii of 5 m and 15 m, with each of the auditoriums having a different DSF opening angle (45°, 90°, and 180°). It was found that the greater the radius of the semi-circular DSF and the opening angle of the DSF system, the greater the area of its glazed surface and, consequently, the greater the availability of solar heating power. Therefore, during the occupation period, only the set of auditoriums with the largest semi-circular DSF radius managed to present acceptable levels of thermal comfort, which were verified from mid-morning until late afternoon. As for the opening angle of the DSF system, the influence was not very significant, although slight improvements in thermal comfort were noted when the value of this angle was reduced (see Case F as an example) due to the corresponding decrease in the volume of indoor air to be heated. In all auditoriums (see Case A to Case F), it was verified that the indoor air quality was acceptable for the occupants, so the airflow rate was adequately promoted by the ventilation system.info:eu-repo/semantics/publishedVersio