English

This paper gives information about the design of displacement ventilation systems for telecommunication equipment rooms, which need an increasing cooling load because of higher density and new generations of telecommunication systems.

This paper discusses design issues for underfloor air distribution systems : design objectives, air distribution issues, occupants comfort issues, control of interior and perimeter zones.

The natural ventilation potential (NVP) is the possibility, or probability, to ensure anacceptable indoor air quality by natural ventilation only. A passive cooling potential (PCP)can also be defined, as the possibility to ensure an acceptable indoor thermal comfort usingnatural ventilation.

The combination of an open wet cooling tower with chilled ceilings is a CFC free, cheap and low energy cooling solution. The efficiency of this alternative to mechanical cooling is very dependent on climate. There is a need for specific tools to help designers to size the system and to estimate its energy and water consumption. A building simulation tool, called ConsoClim, has been used to predict the performance of this system for different French climatic locations, thermal inertia, internal loads and solar gains.

This paper presents the results of a field study on five HVAC duct systems in France. The principal objectives of this work were a) to evaluate the extent of duct leakage in those systems; b) to compare design and actual fan flow rates; c) to evaluate the thermal energy losses in the air ducts. The ductwork airtightness, measured by fan pressurisation method, was found to be in general well above the leakiest EUROVENT 2/2 class (class A), yielding unacceptable uncontrolled airflows. Fan airflow rates were measured with the constant injection tracer gas method.

In this paper, a literature survey on rectangular and round ventilation ducts is presented. The comparison is based on two important aspects: pressure drop and noise radiation. The pressure losses in the ductwork should be kept as low as possible without jeopardizing proper control of the flow rates in the system. Pressure loss through a rectangular duct is significant higher than a volumetrically equal round one. The higher the aspect ratio, the higher-pressure loss in the rectangular system.

This paper describes a modular facade system, which supplies the room behind with the necessary amounts of heat, light and fresh air. Aims of the development of this facade were both to achieve a high degree of comfort for the users and to save energy in comparison to a conventional facade. The experimental investigations to assess and to optimize the facade system were performed in a PASLINK test cell. These test cells allow measurements of the thermal and solar performance of facade elements in original dimensions and under natural climate conditions.

An energy balance over an urban area and over a rural one, reveals that the first case is always more complex than the last one. The urban context is able to change all the energy transferences mainly due to its own layout. Thus, analysing all the energy transferences one by one, we can find how they affect in a different way depending on the surroundings, among other influences.

A field survey on thermal comfort in Algeria has never been previously attempted, and for this reason the present study was conducted. The present paper will present a field study of thermal comfort in Algeria. A thermal comfort survey has been held among 160 persons in 4 towns of Algeria representing three different climatic regions. The survey has been carried out in two different types of buildings: Domestic buildings and Office buildings. Subjective data were collected from 160 people by the use of questionnaires.

In the introduction of the paper are reasons presented, which cause local thermal discomfort. Currently the reasons of asymmetric thermal radiation are not clearly explained. Therefore I oriented my experimetal laboratory measurements, which were carried out in a special microclimatic laboratory on radiant ceiling heating. A special laboratory model of heating of interior was created. The measurements were performed with the help of a thermal mannequin that was used to measure the asymmetric radiation (that is asymmetry of perceived temperature).