Influence of Geometry of Thermal Manikins on Concentration Distribution and Personal Exposure

A number of different thermal manikins have been applied in literature to experimentally study the indoor environment. These manikins differ in size, shape and level of geometric complexity ranging from simple box or cylinder shaped thermal manikins to humanlike breathing thermal manikins. None of the reported studies however, deals with the influence of geometry of the thermal manikin. This paper provides an experimental study on the influence of manikin geometry on concentration distribution and personal exposure of a thermal manikin located in a full-scale displacement ventilated room. The results show no significant influence of manikin geometry on personal exposure whereas the convective flow around the manikins and the concentration distribution at some distance showed to be different. INDEX TERMS Displacement ventilation, thermal manikin, air movement, personal exposure INTRODUCTION In indoor environmental engineering and research occupants are often accounted for by person simulators. In experimental work these simulators can be categorised as either thermal manikins (heat source and obstacle) affecting the room airflow pattern and temperature distribution or so-called breathing thermal manikins that in addition can be used as a tool for assessment of thermal comfort, indoor air quality and personal exposure. A number of different thermal manikins have been applied in literature for studies of airflow, thermal comfort and personal exposure around the human body (Bjorn and Nielsen, 2002; Brohus and Nielsen, 1996; Xing, Hatton and Awbi, 2001; Chang and Gonzalez, 1993; Myers, Hosni and Jones, 1998; Lewis et al., 1969). By means of Computational Fluid Dynamics Topp, Nielsen and Sorensen (2002) and Topp (2002) investigated the influence of geometry of computer simulated persons on air distribution, convective heat transfer, concentration distribution and personal exposure. The results showed that a simple geometry is sufficient when global flow is considered while a more detailed geometry should be used to assess thermal and atmospheric comfort. Little effort however has yet been put into experiments on the influence of manikin geometry. It is straightforward to believe that the more humanlike geometry provides the better results but so far there is a lack of information on how much better the results would be. * Contact author email: ct@civil.auc.dk The objective of the present study is to investigate the influence of manikin geometry on concentration distribution and personal exposure of a thermal manikin in a displacement ventilated room. In another study Topp et al. (2003) studies the influence of manikin geometry in a mixing ventilated surroundings. METHODS A series of full-scale experiments were performed with four highly thermal different manikins as shown in Figure 1. Both thermal manikin 1 and 2 (TM1 and TM2) is a simple rectangular shaped geometry of a seated person based on a standing Computer Simulated Person proposed by Brohus (1997). TM1 has “no legs” that is air is not allowed to pass between the legs, while TM2 has a space between the legs. TM3 and TM4 are breathing thermal manikins with a more complex and humanlike geometry. The manikins are identical with those applied in Topp et al. (2003). Figure 1. The investigated thermal manikins. In the experiments the manikins are located in a mixing ventilated full-scale test room, see Figure 2. The manikins are seated facing the inlet diffuser and the two exhaust openings are located at the top of the same end wall. An additional heat source is placed behind the manikin to establish the desired stratification height. The manikin, heat source and inlet diffuser are centered on the x-axis. Figure 2. Outline and setup of the full-scale test room. Tracer gas was added to the room from a pollutant source above the additional heat source to study concentration distribution and personal exposure. The concentration of CO2 was then TM1 TM2 TM3 TM4