A number of different thermal manikins have been applied in literature to experimentallystudy the indoor environment. These manikins differ in size, shape and level of geometriccomplexity ranging from simple box or cylinder shaped thermal manikins to humanlikebreathing thermal manikins. None of the reported studies, however, deals with the influenceof geometry of the thermal manikin.
This paper presents the performance of a displacement ventilation system in a thermalchamber with tropical subjects. The chamber is served by an Air-Conditioning andMechanical Ventilation (ACMV) system in either Mixing or Displacement Ventilation modes.In the experiments, tropical subjects were surveyed with respect to their thermal sensationsunder different room conditions in either displacement ventilation or mixing ventilation.Objective measurements such as room air temperature, air velocity and relative humidity weremeasured at different heights in the chamber.
This paper will address the shortcomings of typical heat balance-based HVAC design and analysis software when applied to thermal displacement ventilation (TDV) system design. The performance characteristics of thermal displacement systems that lead to inaccurate calculations from heat balancebased programs are discussed. Finally, the paper presents an approach for estimating the performance of TDV systems using existing heat-based calculation tools that responds to most of the significant differences between overhead mixing systems and thermal displacement systems.
One of the major means of air diffusion for air conditioning equipment is the displacement ventilation. The stack effect is used by introducing at a very low speed, in the lower part of the room, some air whose temperature is close to the one of the desired atmosphere.
Istis normally assumed by designers that all pollutants in a displacement ventilation system follow the buoyant air flow into an upper zone, where they are evacuated. But studies have shown that it is not always true and that concentrations of pollutant particles can be found in the breathing zone. This study aims at designing a ventilation system that will minimize the respirable airborne particle in that breathing zone.
A question raised about displacement ventilation, is whether floor heating can be utilised without disturbing the thermal stratification in the room. See Figure 1.Q?Figure 1 Too much floor heating may destroy displacement ventilationThis paper deals with the possibilities and limitations to floor heating with displacement ventilation. This paper shows that floor heating can be utilised with displacement ventilation for both industrial and non-industrial premises for normal airflow rates and normal floor heating rates.
This article aims at precising the difference between Underfloor air distribution (UFAD) and Displacement Ventilation (DV) systems, though they both use supply air delivered into a room or space from an access floor.This article presents each system with its different way of working in applications for commercial buildings.
Thanks to an environmental chamber equipped with a displacement ventilation system, neutral height measurements were carried out with the presence of a heated mannequin and other heat sources.The relationship between the neutral height for air distribution and the ventilation load in a room with displacement ventilation was investigated.
Experimental data for an impinging jet in a room are presented in this paper and non-dimensional expressions for the decay of maximum velocity over the floor are derived. The performance of that system is compared with the one of a wall displacement ventilation.