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Period 2 Projeot Report / EvaluaUon of DisplwemeM Ventilation ..... Page 9 parameters, the former must also be amenable to control by appropriate design and operation of building systems. (e.g. dry-bulb and mean-radiant temperatures, relative humidities, air velocities, contaminant concentrations, decipols, sound pressure levels and frequencies, iiiumination levels, glare, and color temperatures); o existing methods to assess exposure must be capable of detecting or measuring the values specified. The set of human response and exposure criteria proposed for evaluating the performance of the VDV and VAV systems in RDF II is shown in Table 1 of Paper #2, Appendix G. It is further proposed that, for acceptable performance, these exposure criteria must simultaneously controlled. Two system performance criteria have also been proposed in this task: o the system should have suff'iclent capacity to match the design loads and maintain the exposure values to within the specified precisions; o the system should have adequate control to maintain the exposure values within the same precisions at partial loads (i.e., from design loads to minimum occupancy) as those specified for design conditions. From these exposure and system performance criteria, prescriptive system criteria can then be derived from Equations 1 and 4, provided in Paper #2. Simultaneous solution of these equations allows quantification of the prescriptive criteria for parameters that correspond to the selected exposure criteria, the Internally generated thermal and contaminant loads, and the design outdoor conditions. Finally, two criteria for energy and economic performance have been proposed in this task: o a system energy efficiency (SEE) of at least 80% should be achieved; where SEE is

Period 2 Project Report / Evaluation of Displacement Ventiation ..... Page 10 defined as the ratio of energy required to maintain the selected exposure criteria to the energy consumed to provide the desired conditions; o the selected system should minimize life-cycle cost and maximize net benefits. The comparison of aitematives should factor for increased benefits (e.g. productivity) that result from improvements in the environment. This procedure and the resulting criteria is applicable for use in virtual and existing buildings, and for different stages in a building's life cycle. 2.7 Modeiing of Systems (Task B3) We have iniflated the development of a set of models to allow prediction and systems evaluation. Although it is anticipated that this development will continue in future periods, significant progress has been made in this period. Develonment of Models (Task B3. 1) The models developed consist of four elements: (a) A multi-compartment model that inciudes clean and dirty zones within a vertical displacement room. Current attempts at modeling the boundary zones of exterior walls have been limited to conditions where the wall temperature is equal to or exceeds the room air temperature. This model was reported in paper # 3, Appendix G. Future efforts will extend this model to indude conventional variabie air volume systems and boundary conditions where the wall temperature is less than the room temperature. (b) Energy and mass balance models for the HVAC systems. Initial modeling of the HVAC system was reported in paper # 3, Appendix G, in which heat gain, diffuser size, filter efficiency, percent outdoor air, and supply air flow rates and temperature have been considered for a room configured for vertical displacement ventilation. Continuation of this

Period 2 Project Report / Evaluation of Displacement Vendlation ..... Page 11 work will focus on the Integration of the Koganei' model with those previously developed by Woods and Krafthafer (Appendix H1) and Foberlets and Woods (Appendix H2) to include the relationship of heat gain and cooling load to thermal and air quality performance in VAV and VDV systems. (c) Room contaminant distribution model. Important results from the model described in paper 3 (Appendix G) indicate that, for vertical displacement systems, contaminants from heated and non-heated sources rise vertically within thermal plumes in the clean zone and therefore have a minimum horizontal distribution in that zone. However, contaminants from these sources within the clean and dirty zones uniformly mix within the dirty zone. (d) Life-cycle cost model. The model is based on the Net Benefits method which allows factoring for productivity gains resulting from change(s) In the indoor environment. The conventional VAV system constitutes the base case and the various configurations of the VDV system form the alternatives which are compared for economic efficiency with the base case. All future benefits and costs are discounted to their present worth for comparison purposes. The conceptual model is presented in Appendix I. Calibration and further work on the model awaits data on cost break-up from the mechanical contractors of RDF. When Improvements to either of the two systems are undertaken, the economic efficiency resulting therefrom can be determined by comparing net benefits with the base case. Validate%alibrate the model in the FACT chamber (Task B3.2) This subtask originally was to include validation and calibration for unoccupied conditions (i.e. minimum loads), simulated loads, and occupant loads. As the model has evolved, It inherently accounts for occupied and unoccupied loads. Furthermore, in accordance with the 23 November 1992 addendum to the Contract, data were not taken during actual occupancy conditions. Validation of the model was reported in paper # 3, Appendix G, for the specific conditions of 100% outdoor airflow and thermal loads of 13 and 44 W/m2. Data were compared with the predicted curve at two identified values of dirty zone

Period 2 Project Report / Evaluation of Displacement VenUlation ..... Page 12 ratio (see Figure 5a of paper 3 in Appendix G). These results indicated that a general trend existed that was consistent with the prediction. However, there appears to be a better fit for certain contaminants, i.e. particulate and SFe than others, i.e. CO, CO2, and TVOC. We have hypothesized that contaminant specific curves will probably provide better fits. This hypothesis will be pursued in the next period. We also anticipate continuation of the validation process during the next period of the project. Predicted System Performance for VDV and VA V Systems in RDF Il From Results of Tasks 3.1 and 3.2 (Task B3.3) The model developed for predicting thermal and IAQ in the FACT chamber was derived from previous work by Koganei in a VDV system that was configured similar to the FACT chamber. Specifically, this induded low side-wall locations of supply air diffusers and return air grilles in the ceiiing. Our initial analysis of the model developed so far indicates that before this model can be used for predicting system performance of VDV and VAV configurations in RFD Ii, the basic Equation #14 (in paper # 3, Appendix G) requires modification to account for air supply through a perforated floor/carpet in the VDV system and for the ceiling supply air diffuser locations In the VAV system. Our initial attempts to modify the model have been encouraging for the VDV system, but results thus far indicate that acquisition of empirical data will be necessary to accurately characterize the VDV system. Specifically, this will apparently require modification to the characteristic length parameter (bl]°-5, its coefficient and the exponent of the Archimedes number. With regard to the VAV system, the two zone model of Woods and Krafthafer (Appendix H 1) will be integrated with the modei developed so far to predict performance of a conventional ceiiing supply and return VAV system. Obtain Data From RDF ll and Comvare with Results of Task B3.3 (Task 83.4) Data in RDF il have been acquired but comparisons of these data with model predictions for RDF II await further development of the model.

Period 2 Project Report / Evaluation of Displacement Ventilatlon ..... Page 13 2.8 Quality Assurance and Quality Control (Task B4) A Quality Assurance and Quality Control program was Implemented to assure the integrity of the data being acquired. QA/QC procedures for sampling, sample custody, calibration of instruments and data validation were established based on standard protocols. These procedures are discussed on pages 7 through 11 in the 4 March 1993 report (Appendix F). 2.9 Database Development (Task B5) Data storage and retreival capabilities of all the instruments acquired were reviewed. Some of these instruments have internal software to generate data files. Programs used in addition were the B+K 7620 for dosing, monitoring and analyses of gases, (aided by the various B+K linker programs), Microsoft's Excel spreadsheet, and DeltaGraph Pro for generation of graphics. AII data acquired from the FACT chamber In Richmond and RDF II were reduced to a standard format for analyses and comparison. 2.10 Testing at Richmond (Task B6) During the period May 1992 through March 1993, the project staff from Virginia Tech made eight visits to the Philip Morris research facility at Richmond. The VDV system in the FACT Chamber was evaluated on three basic room characteristics: thermal conditioning, air distribution, and contaminant removal. Thermal characteristics were evaluated by analyzing air temperature and air velocity distributions. Air distribution was evaluated by measuring the air change effectiveness using a tracer gas. Contaminant removal was evaluated by measuring contaminant concentrations in the breathing zone in the chamber and in the exhaust air. The contaminants evaluated included TVOC, particulates, C02, CO, and tracer gas. The three basic room characteristics were evaluated as a function of: total air flow rate, percentage of outdoor air, difference between supply and room air temperature, thermal loads, supply and return air device locations, water vapor, and the type and location of the contaminant sources.

Period 2 Project Report / Evaluation of Displacement Ventilation ..... Page 14 The data acquired were used to calibrate the model being developed. A description of these data and some analyses are presented In Appendix G (paper 3). The key findings from these tests are: 0 No thermal comfort problems existed under the tested conditions. O Air change effectiveness measurements indicated partial displacement flow in the test room. Effectiveness increased with flow rate. O Contaminant removal effectiveness data gave no clear indication of the effect of thermal loads and supply air flow rate. These data were influenced by the sample proximity to contaminant sources, proximity to heat loads, the temperature and emission method of the contaminant source, and the type of contaminant measured. O Displacement ventilation can be expected to remove heat loads higher than 44 W/m2 without causing thermal comfort problems. 2.11 Acquisition and Development of Instrumentation (Task B7) Several instruments were acquired during this period. Together with those previously acquired, they provided a set-up for completing the tests during this period. A table listing all major instruments, their identification, and measurement characteristics (parameter, range, precision, accuracy and response) is presented in Table 1 of the 4 March 1993 report (Appendix F).

Period 2 Project Report / Evahiation of Displeoeinent Vendladon ..... Page 15 3 TASKS AFTER COMPLETION OF RDF II 3.1 Baseline Data on Systems in RDF II (Task B8) Supply air flows were balanced In both test rooms. The four supply diffusers in the VAV test room were balanced prior to testing and the nine exhaust grilles each had approximately 0.6 mLs exit velocity. In the VDV room, mean air flow levels from the floor perforations varied by a factor of 2 across the floor prior to installation of the carpet. Installation of the perforated carpet In the VDV test room created a uniform supply distribution. Room temperatures were maintained within 1.5°F in both test rooms and room dewpoint was relatively steady at 53 to 54°F. During both minimum and simulated loads, the VAV test room had a 15 minute cycle time for room temperature and supply air temperature oscillations, while the VDV room had a 45 minute cycle. Supply air in the VAV room cycled between 62°F and 90°F at low load conditions and between 57°F and 83°F at high load. The floor plenum supply air temperature in the VDV room ranged from 70°F to 84°F at low load and from 69°F to 80°F at high load. At high and low load conditions, measurements Indicate that the conventional VAV test room has nearly complete mixing throughout the room. But in the VDV test room, the data clearly indicate two distinctly different zones - a'ciean' occupied zone and a 'dirty' zone near the ceiling. Both contaminant distribution measurements and age of air data support these findings. System volume flow rate measurements have indicated substantial room overpressure leakage, resulting in contaminant travel via floor and ceiiing openings to the mechanical room and into the open volume above the VDV room. Positive pressure in the VAV test room is allowing - 400 cfm total air leakage through the perforated carpet and unsealed floor panels to beneath the raised floor and then across the corridor into the mechanical room via the chiller line access passage. Similarly for the VDV test room, positive pressure is sending - 400 cfm into the open space above the unsealed acoustic tile ceiling and also into the mechanical

Period 2 Projsat Report / Evaluation of Displaosment Ventilatan ..... Page 16 room, possibly via leakage from the induced recirculation at the supplemental fan box in the mechanical room. 3.2 Analysis of Data 4 FUTURE PLANS

Period 2 Project Report / Evaluation of Displacement Ventilation ..... Page 17 APPENDICES A. Contract and Addendum 11/2/92 and 23/2/92 B. Proposal 10/9/92 C. Status Report: Design Process .... 11/18/92 D. SAC minutes 1 l29193 E. Progress Report 11 /18/92 F. Progress Report 3/4/93 G. Publications: AIA Paper (lead: Bob Schubert..) IA Papers: Criteria (lead: JEW) Modeling (lead: MK) with poster Experiment (lead: BWO) with poster Human Response (lead: NPS) with poster IAQ'93 Commissioning (lead: JEW or JS?) H. Publications: Woods and Krafthafer Foberlets and Woods I. Life-cycle cost model

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