English

In this paper the author analyses the different weaknesses of the HVAC systems in case of air contamination by a deliberate pollution of the inducted air due to vandalism, terrorism or any other motives.To prevent that danger he gives some advice about HVAC installation :A safe air intake is necessary, but the intake grille for ventilation must be inaccessible from outside the building and its position at ground level unsuitable.Air dampers must have effective sealing and be closed in the event of a bioterrorist attack.Recirculation systems can be contamined too from a source within the bui

A study on the effect of air temperature on productivity was carried out in telecommunications offices with an observational approach in call centre 1 and an intervention approach in the second call center by installing cooling units.The study shows that the productivity can be reduced by 5 to 7 % when the indoor temperatures increase.

A field survey was carried out to evaluate the thermal comfort perception of the occupants of a naturally ventilated public housing in Singapore to find out if that environment meets the Ashrae standard 55's 80 % criteria of acceptability.That survey also examined the adaptive behavior of the occupants in the use of windows, fans, and air-conditioning . Whether the thermal perception was influenced by different sessions of the day, building height and flat types was also part of the study.

This article describes the physical mechanisms leading to broadband noise from axial fans. It gives the results of a literature survey about the semi-empirical correlations available to predict this noise and their application to two examples : a low pressure fan and a high pressure fan.

Dynamic simulation calculations were operated using TRNSYS software applied to a low energy house. This article is the second one of a serie of two. The first one was dealing with ventilation. This one mainly concerns heating system and domestic hot water production through a gas boiler. It also gives general conclusions, some of them dealing with ventilation.

Compact ventilation appliances appeared on the market for solar passive houses. They include a heat pump to transfer heat from ventilation exhaust air to fresh air and/or domestic hot water. This article describes such systems and gives information about a model for simulating the operation and performance of such appliances which was developped to be used in the TRNSYS software environment.

This article compares the requirements for mechanical ventilation systems in the new German regulation on energy savings (EnEV 2002) with those contained in the previous regulation (named WSchV 1995). It also gives information about the way to test and certify mechanical ventilation components according to this new regulation.

Ventilation systems designed for a constant air volume (CAV) provide fresh air in office buildings. It means that very often huge amounts of energy can be wasted on ventilating empty offices. A simple analysis of the profitability of Demand Controlled Ventilation (DCV) has been performed on a reference office building in Norway.

The aim of that study was to develop a fuzzy controller for naturally ventilated buildings. This paper describes the process of designing a supervisory control to provide thermal comfort and adequate air distribution inside a single-sided naturally ventilated test room.

Maintenance of air-conditioning systems is acknowledged as an important means to run HVAC-systems properly. Although several maintenance programs and standards exist, not many systems are maintained in a proper way. Most standards and programs are not concerned with the indoor environment, they are only concerned with repair and failure-response of system components. Just now, some new guidelines come out in Europe, which contains first definition of cleanliness.