This study describes how the air quality in a displacement ventilated classroom can beinfluenced by the position of a contaminating person, and by the activity of a person who walksaround in the room. Tracer gas measurements have been performed in a full scale mock-up of aclassroom, with person simulators at the student's desks.The spreading of contaminants from a person seems to be strongly dependent on the positionof the person. The closer the contaminating person sits to the outlet terminal(s), the less ofhishers contaminants are spread in the room.
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 simplified is the aim is moreto compare different systems and strategies 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.
Full-scale experiments were made in a displacement ventilated room with two breathing thermal manikins to study the effect of movements and breathing on the vertical contaminant distribution, and on the personal exposure of occupants. Concentrations were measured with tracer gas equipment in the room and in the inhalation of both manikins. Tracer gas was added in the heat plume above a sitting manikin, or in the exhalation through either the nose or the mouth. The other manikin moved back and forth at different speeds on a low trolley.
The use of IR detectors to steer the ventilation is in principle an attractive approach for optimising the ventilation according to the occupants needs. In order to evaluate the performances under real conditions, one of the BBRI office buildings in Limelette (some 31 offices with in total 51 persons and a variable occupation load) was equipped with a mechanical supply ventilation system in which each terminal is controlled by an IR detector.
Occupant-controlled heating, ventilating and air conditioning (HVAC) systems allow inhabitants of open-plan spaces some degree of control over their immediate microclimate. Typically, cooled air is supplied at floor or desktop levels. The amount and direction of air flow is under occupant control. Productivity increases have been attributed to this form of control. This paper proposes a simplified model of the thermal environment created by an occupant-controlled HV AC system and the behavior of the occupants within it.
Occupancy sensors have the potential to significantly reduce energy use by switching off electrical loads when a normally occupied area is vacated. While occupancy sensors can be used to control a variety of load types, their most popular use has been to control lighting in commercial buildings. Manufacturers claim savings of 15% to 85%, although there is little published research to support the magnitude or timing of reductions.
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