In this paper "the ventilability chart" concept is presented and the methodology for drawing it for whatever space is illustrated: its aim is to check the effectiveness of natural ventilation in ensuring comfort levels related to the indoor air quality.Three case studies of calculation of air exchanges by naturally ventilation in typical office room are presented.Through the ventilability charts here proposed, it is possible to determine the conditions under which natural ventilation can be properly used instead of mechanical ventilation.

Fresh air has a very important role in indoor air quality.This study aims at quantifying the costs and the gains of an increase of the ventilation rate, in an office building. Results show that a big increase of the ventilation rate leads to an increase of the installation costs, but to no change of the energy costs. The additional costs may be paid back quickly due to the productivity improvement.

The deposit of particles lower than 5µm diameter, depends on the airflow path within the room along with the strength of the ventilation.This parameter has to be taken into account to predict particle indoor air quality. For that study, a numerical model

The cleaning of HVAC systems aims at removing contaminants and re-establishing the function of the system of ventilation.A measurement method for ventilation cleanliness is discussed in this paper. It is based on measuring the dust deposits inside ducts. Comparison of that HVAC cleanliness method is made with others.

The use of different HVAC system types for office buildings has been analysed within the European funded project EECCAC. This paper presents comments on 7 analysed HVAC system types.Energy performance and consumption are studied in depth (electric equipment, lighting, cooling, heating, fans and pumps)

Three software tools CODYBA (version 6.3), XCUBE and CODYMUR are presented in this paper : - CODYBA for the study of the thermal behaviour of a multizone building with an example of simulation of a building in Seville - XCube for the study of 3D thermal bridges coefficients of the building with examples of application- CODYMUR, for the survey of the thermal behaviour of a partition; that tool makes the inertia phenomenom quickly understood.

A satisfying building commissioning depends on both using right models and using models right. Through 3 case studies, this paper shows how to use simulation models correctly, to commission HVAC systems.

Climate change is a long term battle that involves the whole international community. The need for better energy efficiency is obvious. The energy efficiency of the existing building stock must be improved. Thanks to Information and Communication Technologies (ICT) a lot of possibilities for the development of new type applications and services are present. Internet will be the main platform for the development.

In this paper EIS (Energy Information System) is first defined, then 4 case studies are presented, one in detail because it is an example of high-end EIS and the other cases are summarized briefly. For all the cases operational practices, costs and benefits are presented.

In this paper, an example of how to use the dynamic building and system simulation to design, determine and optimize the characteristics of a heating and cooling system of a school building in southern Germany, is presented.