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Proqr... Report Evalu.tion of WntU.tion bystems November 18, 1992 APPENDIX B PROJECT OVERVIEW EVALUATION OF DISPLACEMENT VENTILATION AND CONVENTIONAL VARIABLE AIR VOLUME SYSTEMS FOR INDOOR AIR QUALITY CONTROL OBJECTIVE The overall objective of this study is to evaluate the effectiveness of displacement ventilation and other control technologies in providing acceptable indoor airquaiity, when internai contaminants, induding environmental tobacco smoke (ETS), are present INTRODUCTION Several research projects are currently focusing on new technologies to more effectively distribute the air in the occupied space. Both, the thermal environment and the indoor air quality are significantly impacted by the method of air distribution. The thermal environment Is affected by air temperature uniformity in the occupied space, I.e., vertical air temperature differences, and draft sensation. The draft sensation is the combined effect of air temperature, mean air velocity, and turbulence intensity. The indoor air quality is influenced by the quality of the supply air, the emission rates of the sources in the space, the degree of contaminant dilution in the space, and the degree of removal from the occupied space. The quality of the supply air is dependent on the quality of the outdoor air and the effectiveness of the cleaning method for both outdoor air and return air. Installation, operation, and maintenance costs also influence the selection of new air distribution systems and are important in determining the overall performance of the system. Within the scope of this research project, internai sources of airborne particulates, gases and vapors are assumed to exist within the occupied space. Consequently, this research will focus Prop« overview B1

Progns R.porl Evalwtlon of V.ntitiibn Syst.ms November 18. 1992 on comparing and analyzing the performance of two HVAC systems: a "conventional" variable air volume system; and a vertical displacement ventilation system known as FACT (Filtered Air Control Technology). Most displacement ventilation systems reported in the literature have supply air through low-wall -supply grilles or raised floor systems with several supply grilles. The FACT system supplies the air via a sub-floor plenum through a perforated floor and carpet and returns the air through grilles in the ceiling. PROCEDURE Exposure data and human responses acquires for each of the two HVAC systems (FACT and conventional) wiii be analyzed and evaluated. The evaluation will be based on established performance criteria, which will be based on naflonal and international standards and guidelines. The performance of the two systems will then be compared with one another. Data will be collected for different test set-ups. To enable system performance predictions under other than the tested conditions, models will be developed to predict the overall performance of each system year round, including life cycle cost Test Set-Up Data will be collected for different set-ups. First, the system performance in vacant office spaces (without furniture or people) will be evaluated. Next, measurements will be taken with only furniture in both spaces. Third set-up will include simulated occupancy: Heat loads will be simulated using electric blankets, and contaminant loads will be simulated using tracer gas and other surrogates yet to be determined. Short term occupancy, people in the room less than three hours, will constitute the fourth set-up. This will allow evaluation of the performance of the systems under real thermal and contaminant loads. Test Conditions Data will be collected for several conditions. The amount of outdoor air, the ~,N total amount of supply air, and the temperature difference between supply and room air will be N IIIA varied. All measurements will be taken when conditions are in steady state. Project Overview B2

Proqro.s Report Evalwtloo of Ventil.tbn Syst.mr November 18, 1992 FACILITIES RDF Phase II Phase II of the Research and Demonstration Facility of the College of Architecture, currently under construction, accommodates two large office areas of 700 square feet each, a mechanical room, and an instrumentation room. The two offices appear idenical and only the HVAC systems are different. One office is served by a conventional VAV system with ceiling supply and a ceiling plenum return. The other office is served by a FACT system, i.e., a vertical displacement ventilation system with supply air via a sub-floor plenum through a perforated floor/carpet, return through the grilles in the ceiling, and ducted back to the air handling unit. In addition the FACT system includes an electronic air deaner and a carbon air cleaner. In this system, the air cleaners can be bypassed to evaluate their influence on the system performance. The RDF Phase II will be used to vaiidate the models under simulated and actual occupant conditions. Test Room at Richmond The test room at Philip Morris Research Center in Richmond will be used to collect initial engineering data and to calibrate the models. This room has an area of 120 square feet and is located Inside a conditioned space. The room is served by a vertical displacement ventilation system similar to FACT, with supply air through the floor. The system can be modified to a conventional system supplying air through diffusers in the ceiling. MEASUREMENT METHODS Thermal Environment Distribution of air temperature, air velocity, and turbulence intensity will be measured. The ability of both systems to provide a thermally comfortable environment will be evaluated by determining vertical air temperature differences, the percentage of people expected to feel draft based on air temperature, mean air velocity and the turbulence intensity, and the ADPI-index. Project Overview B3

Propr... R.part Evaluatbn of VsntUaion syst.ea November 18, 1992 Air Distribution The air change effectiveness, or how efflaentiy the supply air is distributed in the occupied space, will be evaluated using data collected with the tracer gas step-up and decay methods. _ Contaminant Removal and Distribution The contaminant removal effectiveness, or how efficientiy contaminants in the occupied zone are removed by the ventilation system, will be evaluated by comparing contaminant concentrations measured at breathing level with concentrations in the exhaust air. The performance of the systems may depend on the type and location of the source. Therefore, different contaminant sources will be studied, placed at different locations in the occupied space. Gaseous contaminant source will be simulated using tracer gas. Human occupants will be used as sources of particulates, carbon dioxide, and water- vapor. Cigarettes will be used as sources of nicotine and particulates specific to cigarette smoke. Human Response In some of the tests, the performance of the systems will also be evaluated based on human response. Trained and naive panels will be used to evaluate the perceived quality of the air either upon entering the office spaces, or "sniffing" the air sampled from the office spaces. One trained panel will use the olf-decipoi method, the other the forced choice triangulation method. Response data will also be collected from the short-term occupants using questionnaires. MODELING It is important to be able to predict the performance of the vertical displacement system under conditions other than tested and to look at year round performance, including energy use and life cycle cost. For this purpose, a model to predict room air temperature, air velocity, and contaminant concentration is being developed. This model will be validated using the data collected in the test room at the Philip Morris Research Center. The model will be compared with a more detailed computational fluid dynamics model, FLUENT. Energy use will be predicted and evaluated using TRANSYS, a transient systems simulation program. Life-cycle cost will be Pmoa oMVkW B4

ProBtess Report EvNudan of V.ntUation Syst.ms Novembar 18, 1992 evaluated based on methods developed at NBS (National Bureau of Standards Technical Note 1222: A Users Guide to the Federal Building Ufe-Cyde Cost (FBLCC) Computer Program. 1986) and Iowa State University (Manual of Procedures for authorized Class A Energy Auditors in Iowa, Chapter 6: Economic Analysis. 1979). The models will be integrated where possible. PoucY To assure objectivity In this project, the external Science Advisory Committee will continue to review and advise on the protocol to be followed. Test procedures regarding the use of human occupants as sources of thermal and contaminant loads will be reviewed and approved by the Human Subject Committee at Virginia Tech before these tests commence. FUTURE RESEARCH PLANS To study the influence of the indoor environment on human response, including productivity, and the effects of maintenance on system performance, long term studies are needed. The focus of this research plan is the evaluation of the air distribution in the room. Opportunities to improve the system performance are anticipated. As these opportunities are identified, future research plans will be proposed to modify and re-evaluate the system. Other important issues are air cleaning, energy use, and life cycle cost. Studies focusing on air cleaners and reduction of energy consumption, e.g. use of heat exchangers, are needed to address these issues. Projea o"rview