The paper deals with applicability of passive and low energy cooling technologies in the Czech Republic.In the paper there are presented two recent studies, where computer simulation helps to design properly the passive and low energy cooling for buildings is the Czech Republic. There is presented case studies applying,night cooling, thermal mass and slab cooling. The role of computer simulation in the low energy building design and optimalization is discussed.

In this article, the first part of a research project about the modelling of a solar chimney is presented. In this first part, the average ventilation flows measured in an experimentalinstallation have been compared to the results obtained by CFD (Computational Fluid Dynamics) simulations.In order to do so, a solar chimney with a cross-section of 0.78 m x 0.156 m, height 3.6 m, has been constructed.The chimney consists of a glass surface oriented towardsthe south.

The wind-induced natural ventilation of atrium buildingswith two roof openings has been investigated using computational fluid dynamics (CFD) techniques.

The management of indoor air quality is accomplished by various types of complex mechanisms related to indoorenvironment and recently, an integrated solution applying state of art technology is being presented pertainingto the management of indoor air quality.Currently in Korea, an intelligent type certification programis developed and enforced.

In order to overcome the increasing energy demand in buildings and related environmental problems, new efficientenergy technologies and new integrated building concepts, like solar passive and mixed-weighted thermalmass buildings, are being developed. The energy efficiency should not be the only parameter to consider in high-performance building design.

For a high density city, given the need to accommodate a fix amount of building volume, what can one do to optimise the benefits of the natural (air) environment? It is hypothesised that in densely built cities, the amount of gaps, permeability and porosity of the cityscape will affect the ventilation / wind environment. Using wind tunnel, experiments are conducted with different amount and positions of gaps of a simplified city layout.

The performance of natural, mechanical and hybrid ventilation systems was monitored, using the tracer gas decay method, in three typical apartment buildings locatedin two street canyons, during summer period 2002 in Athens. The multi-zone methodology has been adoptedbased on the mass balance of two tracer gases (N2O and SF6) to define the air change rates. The air-exchange efficiency was determined for different ventilation systems,on the basis of the room mean age of air.

The use of windows is a key adaptive opportunity in naturally ventilated buildings especially in summer when the building is likely to be free-running. In these circumstances the use of windows can be on important key to occupants remainingcomfortable, particularly in warm weather. This aspect of buildings is poorly covered in existing thermal simulations in which occupant behaviour is ignored or presented in a very basic fashion. This paper presents an approach to the simulationof window opening behaviour which has been developed from observations of occupant behaviour in UK offices.

It is difficult to design indoor environment under natural ventilation because there is insufficient knowledge to evaluate the effect of the natural ventilation space quantitatively.Especially, natural ventilation rate is not yet fully understood.In this paper, the properties of the naturalventilation with large openings are examined mainlyfrom the measurement result of ventilation rate.

The energy performances of a summer air-conditioningsystem with variable airflow destined fora sole air-conditioned open-space environment which hosts a call-centre are presented. With a simple plant configuration,implementing an opportune control strategy aimed at the simultaneous satisfaction of sensitive and latent loads, the principle energy indexes and thermal comfort with reference to a location with a typical Mediterraneanclimate (Cosenza, Southern Italy) were identified.