Air renewal rate is an important parameter for both indoor air quality and thermal comfort. However, to improve indoor thermal comfort, the air renewal rate to be used, in general, will depend on the outdoor air temperature values. This article presents the modelling of indoor air quality and thermal comfort for occupants of a passive building subject to a climate with warm conditions. The ventilation and shading strategies implemented for the interior spaces are then considered, as well as the use of an underground space for storing cooled air. The indoor air quality is evaluated using the carbon dioxide concentration, and thermal comfort is evaluated using the Predicted Mean Vote index. The geometry of the passive building, with complex topology, is generated using a numerical model. The simulation is performed by Building Thermal Response software, considering the building’s geometry and materials, ventilation, and occupancy, among others. The building studied is a circular auditorium. The auditorium is divided into four semi-circular auditoriums and a central circular space, with vertical glazed windows and horizontal shading devices on its entire outer surface. Typical summer conditions existing in a Mediterranean-type environment were considered. In this work, two cases were simulated: in Case 1, the occupation is verified in the central space and the four semi-circular auditoriums and all spaces are considered as one; in Case 2, the occupation is verified only in each semi-circular auditorium and each one works independently. For both cases, three strategies were applied: A, without shading and geothermal devices; B, with a geothermal device and without a shading device; and C, with both shading and geothermal devices. The airflow rate contributes to improving indoor air quality throughout the day and thermal comfort for occupants, especially in the morning. The geothermal and shading devices improve the thermal comfort level, mainly in the afternoon.

This work presents a study about the design, environment, energy, and comfort in buildings equipped with a Predicted Mean Vote (PMV)-controlled HVAC system. The control system, based on the three categories of the international standard ISO 7730 uses the level of thermal comfort instead of the traditional control of the air temperature. In this type of control, using the PMV index, the air temperature (Tair), air relative humidity (RHair), Mean Radiant Temperature (MRT), air velocity (Vair), level of clothing (CL), and level of physical activity (AL) are considered. The initial four parameters are associated with environmental ones, and the last two are associated with personal ones. The simulation is carried out using a simulator of the dynamic thermal response of buildings and the thermophysiology of the occupants. The simulator considers energy and mass balance integral equations, based on the building’s design. This equation system is generated by the simulator. In this study, three cases are performed: Categories A, B, and C. According to the results obtained, it is possible to verify that it takes some time to achieve acceptable comfort conditions when the HVAC system is connected. However, after the conditions are achieved, the system guarantees acceptable conditions during the occupancy time. Category A provides higher levels of energy consumption than Categories B and C.

The production of thermal energy in buildings using internal greenhouses makes it possible to obtain substantial gains in energy consumption and, at the same time, contribute to improving occupants’ thermal comfort (TC) levels. This article proposes a study on the producing and transporting of renewable thermal energy in a circular auditorium equipped with an enveloping semi-circular greenhouse. The numerical study is based on software that simulates the building geometry and the building thermal response (BTR) numerical model and assesses the TC level and indoor air quality (IAQ) provided to occupants in spaces ventilated by the proposed system. The building considered in this study is a circular auditorium constructed from three semi-circular auditoriums supplied with internal semi-circular greenhouses. Each of the semi-circular auditoriums faces south, northeast, and northwest, respectively. The semi-circular auditoriums are occupied by 80 people each: the one facing south throughout the day, while the one facing northeast is only occupied in the morning, and the one facing northwest is only occupied in the afternoon. The south-facing semi-circular greenhouse is used by itself to heat all three semi-circular auditoriums. The other two semi-circular greenhouses are only used to heat the interior space of the greenhouse. It was considered that the building is located in a Mediterranean-type climate and subject to the typical characteristics of clear winter days. The results allow us to verify that the proposed heating system, in which the heat provided to the occupied spaces is generated only in the semi-circular greenhouse facing south, can guarantee acceptable TC conditions for the occupants throughout the occupancy cycle.

Public passenger vehicles in urban environments, which typically have high occupancy rates, require heating, ventilation, and air conditioning (HVAC) systems capable of meeting both air quality and thermal comfort requirements in demanding environments. Moreover, bus cabins and their HVAC systems must be designed to meet different climate types and external environmental conditions, and also be more energy-sustainable. Thus, this study develops a methodology that takes advantage of solar radiation incident on the glazed surfaces of the bus and establishes airflow rates for the ventilation system that ensure the best compromise between air quality and thermal comfort provided to bus passengers.

Renewable energies can be used in the development of public passenger vehicles to reduce energy consumption and improve passenger comfort and the sustainability of urban environments. Passenger public vehicles, such as trains, are exposed to solar radiation throughout the year, which can be harnessed as photovoltaic energy or thermal energy. This study evaluates the production of electrical energy from the installation of photovoltaic panels distributed across various surfaces on the roof and both sides of a train carriage located in southern Portugal. The energy produced by the panels on the carriage module surfaces could account for 54.6% of the total energy produced.