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This work presents the development of the coupling of differential Computer Fluid Dynamics and integral human thermo-physiology numerical models applied in indoor ventilated spaces. The study 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 on confluents jets system. In the exhaust system, they 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, is 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 Air Diffusion Index increases slightly. The predicted percentage of dissatisfied index values show that the thermal comfort level of occupants is acceptable, the dioxide carbon concentration values show that the indoor air quality is near the acceptable value and the Draught Risk is acceptable.

This work evaluates the passengers thermal comfort level inside a vehicles compartment. The numerical study, made in winter conditions, consider a bus indoor environment equipped with internal curtains, internal seats, lateral panels, ceiling, floor and occupied by 52 passengers. The numerical model considers the passengers and vehicle grid generation, passengers body and clothing thermal response and passengers thermal comfort level. The grid generation is used to evaluate the view factors and Mean Radiant Temperature that the passengers are subjected. In this calculus the passengers and the vehicles surfaces shading devices are considered. The thermal response numerical models consider the energy and mass balance integral equations. The thermal comfort evaluation considers the heat produced inside the body and the heat exchange between the body and the environment. The human body numerical model considers also the thermoregulatory system to control the temperature. The numerical model is used to evaluate the thermal comfort level that seated passengers are subjected in a bus equipped with asymmetrical warm curtains. Three Cases studies were developed: the first one considers the temperature curtains equal to the indoor bus surfaces, while the other two consider higher temperatures values. All Cases are thermally comfortable according to the standards.

This work presents a numerical study of the influence of the ceiling mounted localized air distribution system performance in the human thermal behavior. In his study a coupling of the Computational Fluids Dynamics and the Human Thermal Modelling is used to evaluate the thermal comfort, the indoor air quality and the Draught Risk. The input data, of the coupling numerical models, are evaluated in the Building Dynamics Modelling. The virtual chamber geometry is generated using the Computational Aided Design system and the occupants’ geometry is generated using empirical equations, based on occupant height and weight. The ADI (Air Distribution Index) and the ADTI (Air Distribution Turbulence Index), used to evaluate the Heating Ventilating and Air Conditioning system performance, depends of the thermal comfort level, the indoor air quality level, the Draught Risk level, the effectiveness for heat removal, the effectiveness for contaminant removal and the effectiveness for airflow removal. The study is made in a virtual chamber occupied by twelve virtual manikins and equipped with twelve seats, six desks and with a ceiling mounted localized air distribution system. The ceiling mounted localized air distribution system is equipped with an inlet system and an extraction system located above the head level.

This paper presents a numerical study of sustainable energy application in the buildings construction using cold radiant surfaces in summer conditions. The study is made in a University building and the proposed technology is used to improve the internal thermal comfort conditions in summer conditions. This numerical study uses a software that simulates the whole Building Dynamic Response with complex topology in transient conditions. The numerical model is founded on the balance of energy and mass integral equations. The energy balance integral equations are taken for the indoor air of the compartments, the transparent (windows) bodies of the building, the interior and surroundings bodies of the building and the opaque (walls and doors) bodies of the building. The mass balance integral equations, taken into consideration for the water vapor and the air contaminants, are developed for the spaces of the buildings and the solid matrix (opaque and interior bodies). The software is used to assess the human thermal comfort and indoor air quality levels, the cold radiant system, indoor thermal variables, and other parameters. The building analyzed in this work has 107 compartments, of which 33 are for classes. The radiant system is based on the use of subterraneous cold water. Three situations were analyzed: without cold radiant surfaces, with horizontal cold radiant surfaces and with all compartment cold radiant surfaces. The thermal comfort level, using the Predicted Mean Vote (PMV) index, and the indoor air quality, using the carbon dioxide concentration, are evaluated. The results demonstrate that the implemented Heated Ventilation and Air Conditioned system, working in Ventilation and Radiant methodology, with the use of all surfaces equipped with a cold radiant system, allows to guarantee, in the morning, acceptable, and, in the afternoon, near acceptable levels of thermal comfort by PMV index values according to category C of the standard ISO 7730. During occupancy, the indoor air quality levels obtained in the compartments are near the acceptable limit provided by the ASHRAE 62.1 standard.

A numerical design of a DSF (Double Skin Facade) system subjected to solar energy and applied to the heating of occupied spaces inside a building, in winter conditions, is presented in this study. The simulation is done using a building dynamic thermal response software to assess, among other parameters, the solar radiation incident on the DSF, the occupant thermal comfort level, indoor air quality level and thermal energy production. The occupant thermal comfort level is assessed by the Predicted Mean Vote index. The indoor air quality is assessed by the carbon dioxide concentration. The space considered in this study is an auditorium occupied by 210 people. The DSF system was installed on the south facade of this auditorium. The DSF system consists of 25 DSF. Each DSF consists of two surfaces, an opaque interior and a transparent exterior, separated by an air channel. This channel is used to heat the air that will be transported, through ducts, to the indoor HVAC (Heating, Ventilating and Air Conditioning) system, which is founded on a mixing ventilation system. The thermal energy produced in this way ensures an acceptable level of thermal comfort during most of the occupancy time and a level of indoor air quality close to acceptable. Therefore, it can be concluded that the HVAC system guarantees a good compromise between the thermal comfort of the occupants and the quality of the indoor air.

This paper presents a numerical study on the energy performance of a solar greenhouse used as a heat source in a ventilation system applied in a virtual house. This work, developed in winter conditions, uses a greenhouse and a ventilation system as heating ventilation system. The greenhouse, used to heating the air, is built with a group of glasses turned to East, South and West, placed above the roof, and the ventilation system, built with two groups of ducts, one used to transport the warm air to spaces turned to north and other used to free cooling to spaces turned south. This numerical simulation uses a software, developed by the authors, that simulates the Building Thermal Modelling and evaluates the building internal environment variables, building bodies temperatures, building contaminants concentrations, thermal comfort, energy consumptions, among others. The study, with and without the greenhouse, evaluates the energy production and transport, the internal temperature and thermal comfort to which the occupants are exposed, in transient conditions, during all day. Without the greenhouse system, in spaces with south-facing windows, the thermal conditions are uncomfortable by positive PMV (Predicted Mean Votes) index values, while in spaces with north-facing windows the thermal conditions are uncomfortable due to positive values of the PMV index. Using the greenhouse and the ventilation strategies, all spaces during the occupation are thermal comfortable.

In this study the numerical simulation of the human microenvironment around the occupants is carried out. This numerical work is made inside a virtual chamber, used as classroom, considers the ceiling mounted localized air distribution systems built with one inlet and one exhaust system. The virtual chamber has twelve chairs, each occupied by a virtual mannequin, and six tables. The software, developed by the authors, considers a differential CFD, an integral Human Thermal Modelling and an integral Building Thermal Modelling numerical model. The inlet and exhaust ventilation systems promote, respectively, a downward airflow and an upward airflow in the occupied zone. The study, made in winter conditions, evaluates the thermal comfort, the indoor air quality, the Draught Risk, the Air Distribution Index and Air Distribution Turbulent Index. The results obtained in this work allow us to infer that the thermal comfort, indoor air quality and Draught Risk are acceptable according to what is proposed in international standards.

This article presents a case study of a multiple confluents jets system in a virtual chamber. In this study, it is obtained the behavior of the airflow in an office, simulated by a virtual camera, whose ventilation system is of the horizontal confluent jets type. The ventilation system has an inlet system consisting of four vertical ducts mounted in the corners of the compartment. Each duct has four groups of 32 nozzles, aligned and equally spaced, positioned from the base of the duct close to the floor. Each two groups of nozzles are directed towards each of the walls adjacent to the duct The exhaust system consists of a quadrangular vertical duct mounted close to the ceiling and positioned in the center of the compartment. The study uses a numerical differential model in order to simulate the Computational Fluids Dynamics. Ventilation by horizontal confluent jets creates a horizontal air velocity close to the wall surface as well as the floor surface. With the increase in the exit velocity of the jets, the interactive effect of the confluence of the jets, coming from opposite ducts, in the central area of the wall becomes more evident. The airflow resulting from the interactions of the jets has an upward characteristic towards the exhaust system.

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.

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 acceptable.

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.