An experimental campaign was organized during the summer period 2002 in Athens, in the framework of the European RESHYVENT Project. The main purpose was to indicate the impact of the urban environment on the natural and hybrid ventilation air flow process in urban canyons. Field and indoor experimental procedures were carried out in two urban canyons, presenting different geometric and urban features. The experiments were organized for more than three consecutive days within three different periods in summer and on a 24-hour basis.

The IEA ECBCS Annex 36 deals with the energy retrofit of educational buildings. Researchers from 10 participating countries from Europe and the US are collecting information on retrofit measures and case studies and are developing an energy concept adviser for technical retrofit measures. This internet-based computer tool for decision-makers is the main outcome of the annex. One of the most important inputs to the tool is the collection and assessment of case studies, which is also presented in a specific report.

In Arctic and sub-Arctic climates, such as those in Scandinavia, multiple-glazing windows that consist of at least three panes are widely used. Typically, the replacement air for the extracted air, especially in low-cost accommodation with forced extraction, enters the interior space in the form of leakage flow through the window jambs and the walls or through the supply air vents. The temperature for the air entering the room is close to that of the outdoor air, which may cause a sensation of draft.

From the view point of designing the energy efficient air conditioning system with maximized ventilation, the possibility of an all fresh air system was discussed using the simulation results of a model building in Tokyo. The algorithm of single duct cooling system for simulating the cooling coil of air handling unit based on the heat balance model of whole system components is also described as a base for the simulation of cooling effect of ventilation fresh air.

For the multi-room ventilation calculations, bi-directional flows or counter flows in openings have been rarely taken into consideration and only uni-directional flows have been allowed for the calculation. It stands to reason that the calculation requires quite sophisticated scheme and the appearance of the bi-directional flows are restricted only to a limited number of openings neighboring the neutral plane of the building and also the flow rates may be too little to affect the total building

The design for the new Federal Building for San Francisco includes an office tower that is to be naturally ventilated. Each floor is designed to be cross-ventilated, through upper windows that are controlled by the building management system (BMS). Users have control over lower windows, which can be as much as 50% of the total operable area. There are significant differences in the performance and the control of the windward and leeward sides of the building, and separate monitoring and control strategies are determined for each side.

The design for the new Federal Building for San Francisco includes an office tower that is to be naturally ventilated. The EnergyPlus thermal simulation program was used to evaluate different ventilation strategies for space cooling and rationalize the design of the faade. The strategies include ventilation driven by different combinations of wind, internal stack and external stack. The simulation results indicate that wind-drive ventilation can maintain adequate comfort even during hot periods.

Considering the natural ventilation, the thermal behavior of buildings can be described by a linear time varying model. In this paper, we describe an implementation of model reduction of linear time varying systems. We show the consequences of the model reduction on computing time and accuracy. Finally, we compare experimental measures and simulation results using the initial model or the reduced model.

In this work two numerical models are presented. The first one simulates the buildings thermal response and evaluates the internal air quality, while the second one simulates the human and clothing thermal systems and calculates the thermal comfort level in non-uniform environments. The results obtained by the first model are used as input data in the second one.

At the new institute building of Fraunhofer ISE, both mechanical and free night ventilation is used for passive cooling of the offices. The results from a monitoring of room temperatures in 21 office rooms during summer 2002 show that room temperatures exceeds 25 C in less than 8 % of the working hours, even at high ambient air temperatures. In two offices, experiments were carried out in order to determine the efficiency of night ventilation dependent on air change rate, solar and internal heat gains. During the experiments, meteorological data, air change rates, air temperatures (incl.