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EVALUATION OF A VERTICAL DISPLACEMENT VENTILATION SYSTEM 8jarne W. Olesen', Makoto Koganeil,z, G. Thomas Holbrook', Julie Seeient, James E. Woods' t Indoor Environment Program, Virginia Polytechnic Institute and State University, U.S.A. 2Research and Development Center, Asahi Kogyosha Co., Ltd., Japan SUMMARY A vertical displacement system supplying air through a perforated carpet/floor was experimentally evaluated. The performance was evaluated using ADPI, percentage dissatisfied due to draft, vertical temperature profile, air change effectiveness and contaminant removal effectiveness. Combinations of supply flow rate and Internal heat loads were tested. Air change effectiveness varied from 120% to 200%. Contaminant removal effectiveness varied between 100% and 700%. METHOD Two sensible heat loads (13 and 44 W/m2) and two air change rates (8.5 and 26 ach) were utilized. Contaminants measured were COz, CO, particulates and SFa. Air temperatures,, velucities, and gas and particulate concentrations in steady state conditions were measured at five locations each at live heights (0.1, 0.6, 1.1, 1.7, and 2.5m). Age-of-air was measured by the tracer gas step-up method. Q e3 0 .~ .L O4] a.r ® IIKarWl9I1rM krnuoe 0 Kwr~ M. ~r1Hki t:3w I,r~. . . . . . _ _ r f f f f f f f ~OM pl R,rn% plan wieA plbaao roMike JrsinR (b) Rn.a reclwm witl~ meawrannM beiEMs u-r anJ aattr iu dmillg N•s-. anwmawL . Figure 1. Schematic of test room THERMAL COMFORT AUPI (Air 1)iffusion Performance Index), 1'i) (Percentage I)raft), and vertical air temperature differences (0.1-1.1m and 0.1-t.7m) were calculated. . All values were within established comfort criteria. lriptitt 1."m rwmave3age hapJssJ.7m room.rnage 1.1ho0.'Im 11'lo0.tm ADPt PD s 1596 Vertiut Temperature Difference Figure 2. Measured comfort parameters VENTILATION EFFECTIVENESS I'wo Air-Change-Effectiveness (ACE) values were caiculated by, dividing the local age-of-air in the return duct by either I) the age-of-air at a height of Llm, or 2) the room average age-of-air (as measured in (lie return). '1'wo Contaminant Removal Effectiveness values were calculated by: (:R1: = (t;relrra'( .~ppty)I(Croom-t'suppl,~ for a Cr„am measured at a i.ltn height or averaged over the occupied zone (height <_ 1.7m). DISCUSSION AND CONCLUSIONS 30 uM 3/0 Airs.ppb st• - lea uM l,.a,.w~ 2 u; .. ..... . ............... Percenc .............................. ................................ : ........... ........ .... ; ............... ~ :.............. ............. ................... ............ ...........:.....: .......... ........ ............... ~ .................... :: ::.. ......_.. ...... ................................ i.....: ........ i ' ............... .ee ._-_ - .. .;..~ aeo _._ + tw ~: e •L1ww"oY naw.~e rlLbplt M"iI.^.w. aL1aMrM NS31fL7w. aLSirwpc bght1.1. ACE CRE-CO, CRE-CO CRE-SFr Figure 3. Measured ventilation parameters -Aithough the measurements were not highly repeatable, (hey clearly indicate displacement flow with effectiveness higher than 100%. No clear Influence of heat load and supply flow rate magnitudes is apparent. Air Change Effectiveness seems tu increase with flow rate. The wide variations in the Contaminant lCetnoval Effectiveness data indicate Ihe need for a well defined measurement method. A standard method must address themeasurement locations in the lest area and their proximity to the contaminant sources as well as the type of sources. No thermal comfort problems existed under the tested conditions. ~ ~ N N N *a m ~ r ACKNOWLEDGEMENT "ilus study is fundedby Philip Morris.,USA and supported by Asahi Kogyosha Co., Ltd., Japan.