English

Since the beginning of this decade, natural ventilation in office buildings is receiving specific interest. There are two sorts of application. Natural ventilation can be a strategy for indoor air quality control. Besides it can be used as night ventilation during warm or hot periods. In this case the objective is to cool down the thermal mass and improve the thermal summer comfort. The EC JOULE NatVent project wanted to identify the barriers to the application of natural ventilation in office-type buildings in moderate and cold climates and to provide solutions.

The acoustic environment was examined in an office building with a high prevalence of symptoms typical of the sick building syndrome (SBS). Levels of ventilation noise exceeded 70 dB in many rooms. The peak was often found in the region below 20 Hz, which is the infrasound region and generally regarded as inaudible at these levels. Symptoms attributed to exposure to low frequencies include nausea, headache, choking, coughing, visual blurring and fatigue, which appear to overlap with some of the symptoms of SBS.

This paper describes a European project to produce comprehensive design guidance on urban layout to ensure good access to solar gain, daylighting and passive cooling. The project involves:

The purpose of this work is to evaluate the air infiltration through the high buildings and in the same time to determine the exchange of the air between the rooms and the influence of the heat transmission for these exchanges. The method of approach for this problem is a network model. This is a grid system in which the nodes are the rooms or zones of the building and the connection between two nodes simulates a flow path of a given resistance. It was built a computer program for predicting the interactions between different zones which was applied for a given case of a building.

A simplified natural ventilation model for dwellings is developed and used to determine the impact of different ventilation strategies on the building loads and zones temperatures. It deals with the sensitivity of loads and temperatures to classical default parameters as : wind velocity, wind coefficient value, building environment and shielding conditions, and the actual cross section of the openings. All the simulations are performed using the TRNSYS 14.2 simulation software, TYPE56.

The present energy consumption of European Buildings is higher than necessary, given the developments in control engineering. Optimization and integration of smart control into building systems can save substantial quantities of energy on a European scale while improving the standards for indoor comfort.

The work presented in this paper was done in 1997 as a final thesis in mechanical engineering, supervised by TRANSSOLAR Energietechnik GmbH in cooperation with the Institute for Thermodynamics and Heat Technology (ITW), University of Stuttgart. The contents of the work is the investigation of natural ventilation through window openings (single sided and cross ventilation) in an existing office space. Both measurements and computer simulation have been conducted.

This paper describes the results coming out of the European Commission supported THERMIE Target Project Energy Comfort 2000. This was the first Target project, containing eight non-domestic buildings, started in July 1993 and to be completed at the end of 1998. The project aimed to design and construct buildings which use less than 50% of the energy of a traditional equivalent, by using passive methods, particularly to avoid the need for air-conditioning. High quality internal conditions were to be achieved.

The present study applies the N3S CFD code to the air cooling simulation on an "architectural reference object", namely the "Maison Ronde" of Mario Botta. The summer night situation is examined when natural ventilation creates indoor air motion and cools the building structure. The transient behavior of the walls is represented by a thermal model coupled with the CFD code. The simulation evaluates the unsteady temperatures of the outdoor and indoor air flow together with those of the wall surfaces.

This study is a contribution to European projects Pascool/Joule II and Altener/Sink that deal with the usability of passive cooling systems in Europe. The first phase of this work was to define design methodology in order to evaluate natural cooling potential according to the climatic quantification criteria of the site, the cooling needs of the building, the cooling system performances, and comfort criteria defined by the couple of temperature and relative humidity set points.