This paper critically reviews current and previous research into the use of displacement ventilation in commercial offices with and without supplementary static cooling devices. It also reports the findings of a preliminary study of a displacement ventilation technique that may increase the scope of application for displacemelllt ventilation systems without the need for supplementary static cooling.
This paper presents general guidance on designing for thermal comfort in combined chilled ceiling/displacement ventilation environments. Thermal comfort measurements involving 184 human subjects were carried out in a laboratory- based test room, constructed to resemble a normal office and equipped with a combined chilled ceiling and wallmounted displacement ventilation system.
This paper reviews several aspects of the performance of displacement ventilation: temperature distribution, flow distribution, contaminant distribution, comfort, energy and cost analysis, and design guidelines. Ventilation rate, cooling load, heat source, wall characteristics, space height, and diffuser type have major impacts on the performance of displacement ventilation.
In March of 1996, a new Elementary School was occupied which is the first in the United States to utilize the concept of displacement ventilation as the primary means of providing both good indoor air quality and thermal comfort. In addition, the integrated "sustainable" design concepts of the facility also address other important factors including: siting, programming, lighting, acoustics, energy efficiency, classroom computer usage, and access for planned HV AC preventive maintenance.
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.
Thermal performance of the floor-supply displacement ventilation system was evaluated in a large climatic chamber designed to simulate a single span of an office building. Detailed measurements were conducted to determine the indoor environment and skin temperature of a thermal manikin Temperature gradient in the room could be kept smaller, compared to conventional wall-supply unit displacement ventilation system, owing to the floor cooling effect of the floor-supply system.
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