The vortex ventilation system (VV) which uses a rotating finned swirler installed coaxially with the exhaust duct is a very effective local ventilator. VV can enhance the capture depth by a factor of 3-5 compared to the conventional exhaust hood, in the absence of any solid walls nearby. In real situations there may exist ceiling, side wall and floor, all of which can affect the flow field and suction performance by way of the no-slip condition on the walls. 3D CFD simulation was performed in order to see the effect of the floor on the capture performance of the VV.

The aim of this study is to analyse the physical characteristics of airborne virus, consider thepossibility of using coupled analysis model and tracer gas for analysing virus diffusion in buildingspace and, based on reports of how the infection spread in a hospital where patients were discovered, analyse infection risk using tracer gas density and also diffusion patterns according to the location, shape, and volume of supply diffusers and exhaust grilles.

Due to the increase in CO2 emissions and the resulting climate change more and more efforts aremade to reduce energy consumption. As a result, the energy demand of buildings is to be reduced by specific measures, for example thermal insulation or intelligent ventilation systems. A demand-based (moisture-controlled) exhaust ventilation system is assessed in comparison to a supply and exhaust ventilation system with heat recovery by means of computational investigations.

The French regulation on residential building ventilation relies on an overall and continuous airrenewal. The fresh air should enter the building through the habitable rooms while the polluted air isextracted in the service rooms. In this way, internal air is drained from the lowest polluted rooms to thehighest polluted ones. However, internal pressure equilibrium and air movements in buildings resultfrom the combined effects ventilation system and parameters such as wind, temperature difference or doors opening.

Passive cooling of buildings is one of the energy-saving measures that can be employed in climateswith predominantly sensible cooling loads. There are several passive cooling techniques that can be used in buildings; among them night-time ventilation. Night-time ventilation cooling utilizes diurnalswing of outdoor temperature and it has been used in many buildings. However, this passive coolingtechnique only works well when a building has a sufficient thermal mass.

In most Dutch classrooms draught results in insufficient ventilation and poor air quality during the heating season, adversely affecting the well being and performance of pupils. Also a considerable part of the year the risk of overheating is high due to the high internal heat load. New analyses show that over 85% of time the heat load and not minimum indoor air quality is the determining factor for the required amount of ventilation. That is if passive cooling is to be preferred above mechanical cooling, with regard to energy conservation.

Due to increasing interest in indoor air quality and demand controlled ventilation in buildings aiming at energy and cost saving, as well as health and comfort aspects, the objective of our work has been the development of a reliable, low cost tool for demand ventilation control. Based on a single microelectromechanical (MEMS) metal oxide semiconductor (MOS) gas sensor VOC detection as close as possible to perceived air quality and additionally, a good correlation with measured CO2 concentrations due to implementation of an empirical data evaluation algorithm has been achieved.

The dependence of the ventilation on the indoor particulate pollution is highlighted by numerousstudies. The aim of the present study is to examine the influence of the ventilation on the levels of theparticulate concentrations found in dining halls where a large number of students are accommodated. Indoor particulate sources were also quantified.Measurements were conducted in four University dining halls, which are located in different parts ofthe city of Athens.

Since the 2002/91/CE EPBD was published, all European countries should making efforts in harmonizing local standards, imposing the assessment of building energy and environmental impact through a common certification procedure. Generally speaking, as a matter of fact, beside the main problem of different methods and tools adopted for evaluating the building energy balance, ventilation is still one of the controversial issues, since each country refers to different local requirements regarding the air-change rate values to be used when performing the calculation.

International building legislation is setting stronger and stronger requirements for the energy performance of buildings. An actual example is the impact of the Energy Performance of Buildings Directive in the European Union (EPBD) on the national requirements in the Member States. The improved energy performance of buildings cant be achieved by additional insulation or more effective buildings systems only. A major influence factor on the energy quality is the ventilation technology and also the airtightness of the building envelope.