Tobacco Documents Online

progress Report Evdu.tion of V.ntiladon Systsms November 18, 1992 APPENDIX A ABSTRACTS FOR INDOM AIR '93 Modeling the Thermal and Indoor Air Quality Performance of Vertical Displacement Ventilation Systems Makoto Koganei, Douglas J. Nelson, G. Thomas Holbrook, Bjame W. Olesen, James E. Woods Previous experiments with a vertical displacement ventilation system show that a room with heat sources divides into two zones: a lower "ciean" (unmixed) zone with temperature stratification connected by a heat source plume to an upper "dirty" (mixed) zone with an almost uniform temperature distribution. Contaminants added to the upper zone mix with the turbulent air flow in this zone while contaminants added to the lower zone do not mix, but instead slowly ascend until entrained by heat source plumes. Past attempts to model vertical displacement systems have not fully accounted for the different nature of the air flow and temperature distributions within these zones. These models have typically assumed envelope surface temperatures equal to indoor air temperatures, uniform temperatures and contaminant mixing within each zone, and a recircuiation factor applied between the two zones. For these models, air change effectiveness and contaminant removal effectiveness can only be evaluated for a specified recircuiation factor and clean zone height, both of which are not easily quantified for a given room condition. The effects of internal heat loads, non-isothermai wall or surface temperatures, and temperature stratification on air flow pattems and the resulting air quality have not been accounted for In these models. In the results described herein, modeling of vertical displacement ventilation is improved by assuming piston flow in the clean zone and uniform mixing in the dirty zone. Recirculation between the zones is eliminated except via heat source plumes. In cases where the supply air temperature exceeds the room air temperature, this model predicts one uniformly mixed dirty Abstracts for Indoor Aiu'93 Al

pro8np peport Evaiuation of Ventiiation Syst.ms November 18, 1992 zone. The dean zone height is estimated based on experimental correlations as a function of heat loading conditions. The resulting equations for air change effectiveness and contaminant removal effectiveness more closely match observed vertical dispiacementventiiation performance than previous models. Evaluation of a Vertical Displacement Ventilatlon System Bjame W. Olesen, Makoto Koganei, G. Thomas Holbrook, Julie Seeien, James E. Woods Today many research projects and new technologies are focusing on a more effective air distribution in occupied spaces. It is important to recognize the effect the air distribution has on both the thermal environment and indoor air quality. The thermal environment is influenced by the air change effectiveness: how efficiently the air is distributed in the occupied space; and the ADPI: air diffusion performance index. The indoor air quality is influenced by the contaminant removal effectiveness: how efficiently the contaminants are removed from the occupied space. The objective of this study is to evaluate the effectiveness of a vertical displacement ventilation system, when contaminants including tobacco smoke are present. Most displacement ventilation systems reported in the literature supply air through low-wall supply grilles or raised floor systems with several supply grilles. The system tested in this study serves a controlled room and supplies the air through a perforated floor and carpet and returns the air via grilles in the ceiling. The air change effectiveness was determined using the tracer gas technique. To evaluate the contaminant removal effectiveness tracer gas was used to simulate contaminant sources. Also particulates and CO2 were measured while the test room was occupied with smoking and non- ~ smoking persons to evaluate contaminant removal effectiveness. The ADPI, draught risk, and ~ vertical temperature profile were evaluated using air temperatures and air velocities (mean value N and turbulence intensity) measured at different points in the room. The system was evaluated ~ m ~ ~ N Abstracts for Indoor Air '93 A2

Prow*s HapoA Ev.lwtion of Y.nW.tlon Syst.ms Nowmber 18, 1992 for several combinations of supply airflow rate and temperature difference between supply air and room air. Because the air was supplied through the entire floor, very uniform air temperature and velocity conditions were obtained. The risk of draught was found to be very low. The air change and contaminant removal effectiveness of the system depended on the temperature difference between supply and room air, location and type of heat sources in the occupied space. Contaminant removal effectiveness also depended on the location and type of the contaminant source within the occupied space. Establishing Rational Building Performance Criteria for Improved Indoor Environmental Quality James E. Woods, Ph.D., P.E. and Sanjay Arora Meeting the "expectations of the user" is increasingly being accepted as the objective of design. Compliance with codes and standards is not sufficient to meet this objective. The concept of specifying performance criteria is therefore gaining ground. Performance criteria identifies user satisfaction as the primary objective. It includes four elements - structure, envelope, interior spaces and services, and is measured over the life-time of the building. The users' physiological responses to the environment are in terms of acceptability and comfort when exposed to the environmental stressors (air quality, thermal, acoustic, and iUumination) in the occupied spaces. Building service systems are employed to respond to the stressor loads in the space through appropriate design and control strategies. Our hypothesis is that the performance criteria for each of the four building elements cannot be treated independently of each other because of the complex manner in which they relate. Performance criteria should therefore address the complex interaction between the buildings, their systems, the occupants, and the economics of owning and operating these buildings. Absaaas tor Gr4oor Arc *93 A3

Proqra.s Report Evdwtjon of Ventilation Syst.ms Nowmber 18, 1892 In this paper we propose that performance criteria should be developed for each stage of the building's life cyde, starting with the original building concept As we move along the life cycle, there is a need to express the performance criteria in different forms. To enable construction, for example, performance criteria has to be translated to prescriptive criteria. At a later stage, when the building Is completed and operational, the originally determined performance criteria shall again become applicable. All expressions and transformations of performance criteria should be rational and consistent. A rational modeling process that enables this transformation will be presented. Also discussed in the paper will be the physiological, psychological, sociological and economic implications of the performance goals that should also be taken into account, and the need for performance criteria to be suitable, reliable and flexible. A Comparison of Methodologies Assessing Human Response to the Indoor Environment Nisha P. Sensharma, Patricia K Edwards, James E. Woods, and Julie Seelen A major factor that may account for divergent results reported in indoor environmental studies is hypothesized to be related to the variety of methods used for assessing human responses. The objective of the study, reported herein, is to characterize the most frequently reported methods In terms of extraneous factors related to human response domains, and in terms of design effects, i.e., measurable effects resulting from the design and execution of the study itself. Through a literature review, three classifications of methods were defined: those that use panels, subjects, or occupants. Human responses were then characterized in terms of four human response domains: Environmental-perceptive, Personal-perceptlve, Environmental-affective, and ~ Personal-affective response domains. The three types of methods were then examined to identify ~ extraneous factors and design effects that may confound results for each human response CA domain. Results indicated that a set of extraneous factors can be arranged in a hierarchy %] ~ ~ ~ Abaaacts for Indoor Air •93 A4

ProWO" R.pott Ev.lu.tion of V.Milaion SysMms Novembar 18, 1992 associated with the four human response domains. However, each type of method has a different set of design effects that may also confound results. It is concluded that- methods to assess human response can be selected and improved by systematically matching the human response domain to be evaluated with the extraneous factors associated with it and the design effects associated with the different types of methods. Abstracts for Wdoor Air '93 A5