In the beginning of 1998 the European project, AIRLESS, was started to develop strategies,principles and protocols to improve and control the petiormance of HVAC-systems and itscomponents for the incorporation in codes and guidelines. The project is divided in 6 tasks.The Hermann-Rietschel-Institute deals with the second task of the project, the maintenance ofHVAC-systems. People stay approximately 90% of their lifetime in enclosed rooms. Theserooms are often served by HVAC systems. In recent years poor indoor climate has causedhealth problems in buildings.
The pattern of airflow influences the propagation of airborne pollutants, the thermalenvironment and general comfort conditions. In designing a good HVAC system, it isideal to determine the airflow distribution in the occupied zone to ensure good quality ofair and comfort condition are provided to the occupants. In most instances, it may not befeasible to conduct such study experimentally. This paper presents an investigation on thepredictions of air movement within a room and compared them with the physicalmeasurements.This study is carried out in a seminar room at a University.
During the last decade, an increasing interest in Underfloor Air-Conditioning (UFAC) systems has emerged. This is due mainly to an increased demand from employees for a greater control over their working environment. And the building and its engineering systems not only have to be designed to achieve the high standards of environmental control at economical cost, but also thermal comfort is an important factor that influences occupants' satisfaction with the indoor office environment.
Until now, there is no widely accepted way to express any index for this purpose and takinginto account the large variety of possible pollutants. Things can be simptied if the aim k tocompare different systems and strategies rather than to give an absolute value of quality.For the study of a pollutant source, the main important point for comparison is the pattern ofits production, whatever this pollutant is. The detailed data for each inhabitant is the curve ofthe number of hours above a pollutant level concentration.
House-dust mite antigens are a major contributor to allergic sensitisation. Since temperatureand humidity are crucial to house-dust mite physiology, there is considerable interest inreducing mite populations by controlling the indoor environment.
This paper reports the results of thermal comfort and indoor air quality studies in forty-three flights with a duration of more than one hour. The measurements were performed continuously during the whole flight (from the departure gate to the arrival gate) and the parameters monitored were temperature, relative humidity and carbon dioxide concentration. The results were then compared with the ASHRAE Standards for the thermal and indoor air quality.
The purpose of this work is to evaluate the thermal comfort of human beings in outdoor spaces, taking into account the microclimatic modifications produced by vegetation. The parameters needed to formulate a comfort index are of differing orders of magnitude, so the same conditions could be seen as comfortable outdoors and yet be unacceptable indoors. One of the most influential landscape elements in the degree of comfort is vegetation. The main effects of vegetation are on solar radiation and wind.
The greater availability of information and telecommunication technologies and the trend towards flexible working practices allow the home and the workplace to coexist. Many studies mainly emphasize economic and social consequences of teleworking. However, there is no assessment of energy and indoor climate impact of teleworking at home. Furthermore a professional activity is usually not envisaged at home, and home is not built according to the same building design process as offices. Consequently, teleworking at home raises new questions about the evolution of dwellings.
Since reduction of ventilation rates in dwellings for economical reasons, it has been necessary to study whether this reduction had not been done to the detriment of indoor air quality. Several means of investigating were developed: experimental tests are indispensable but usually expensive that is why numerous research centres choose to model the thermoconvective fields in rooms.
The energy saving practice of stopping ventilation systems at night may reduce the daytimeair quality. Sorption phenomena where pollutants absorbed at night are reemitted during theday and the general slower removal of pollutants at the reduced average ventilation rates willcontribute to the deterioration of air quality at intermittent running systems. The purpose ofthe study was to investigate the impact on construction product emission during the day fromreduced ventilation rates at night. Experiments were performed in three small-scale chambersof Climpaq type with dilution systems.
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