This paper presents an on-going research programme about the performance of a natural ventilation system in a 3-storey building (with 2 aparments in every floor) in Portugal.

This paper deals with the steady state simulations carried out with the CFD software Flovent along with dynamic building energy simulations using the ESP-r programme applied to three buildings (located in Ireland, Poland and Denmark) intended to be equipped with supply air windows coupled with passive stack ventilation systems. Supply air windows consist of two layers of glazing separated by a ventilated layer. Air enters the cavity at the bottom from outsides and enters the building at the top. Systems design from simulation results is discussed.

Prediction of airflow and pollutant transfers in a simple multizone building may use different approaches such as zonal or nodal modeling methods. This paper proposes to improve the modeling of pollutant transport by coupling nodal and zonal models in the SPARK simulation environment.
Nodal model gives mass airflow rates used as boundary conditions in the zonal model to predict pollutants mass transport. Simulation results are compared with experimental data from the 2 zones testing room Minibat.

A simple conceptual approach to room surface convective heat transfer is presented, defining a global room heat transfer coefficient. It is applied to two room ventilation systems : mixing and cross-ventilation.

Overnight free cooling in buildings brings potential benefits that have been known for some time. This study investigates those benefits when used in conjunction with an under floor air delivery system (UFAD). A detailed study using CFD was undertaken for a building in an airport in the UK with under floor air conditioning system and mechanical ventilation providing fresh air. Results show the energy consumption and peak cooling loads reductions when using night time cooling with outside air during the cooling season.

Advantages of floor supply and floor return systems (UFAD: under floor air distribution systems) are described. They are presented by the author as being capable of better performance (thermal comfort, indoor air quality) than floor supply and ceiling return system. They also offer flexibility and ability to allow individual control.

Variations in heat source positions in a room bring changes in the ventilation effectiveness. Those changes are studied using experimental data and CFD results. Results show that a good ventilation effectiveness can be achieved when the contaminant and the heat source are located close to the zone containing the exhaust opening.

The concentration of fungal spores is higher in the crawl space than inside houses. Domestic mechanical exhaust ventilation systems may create air flow between crawl space and base floor through leaks. This study used data from eight buildings to develop a model providing relation between indoor and crawl space fungal spores concentrations. Results show that the correlation between the fungal spores in the crawl spaces and indoors depends on the size range of microbe species.

In an air-conditioned office building in Singapore, 3 different filtration systems have been evaluated under similar fresh air intake and ventilation rate conditions (electrostatic filtration, electrostatic filtration with chemical adsorption, and media filtration) . Chemical and microbial contamination levels under different filtration strategies have been monitored.

A method for analyzing the thermal and lighting radiations in offices building has been developed. It enables the simulation of complicated lighting environments composed of a combination of artificial lighting and solar radiation, in ventilated and air conditioned offices.