#13,510AIVC..., I
A DESIGN PROCEDURE FOR Displacement Ventilation
ALEXANDER ZHIVOV, PhD, PE; By M. Two approaches are used for pas lines that resulted from the 1995 re PETER NIELSEN; Y. sive-thermal-displacemen t-ventila search project "Design Guide for Dis GERALD RISKOWSKI; and tion design: The first is based on the placement Ventilation" conducted by EUGENE SHILKROT analytical model, while the second International Air Technologies Inc. relies on computational-fluid-dy and sponsored by Philip Morris Man 2 3 isplacement-ventilation namic (CFD) codes. The analytical agement Corp. ' systems are commonly used approach is by far the most-used . in European countries. Dif method of designing displacement APPLICATION D ferent types of systems systems. CFD codes can be useful in Thermal comfort and indoor-air called "displacement ventilation" designing displacement ventilation quality in most industrial and commer were described in our previous article for large rooms because th.ere is suffi cial spaces can be equally maintained 1 published in HPAC Engineering. In cient data in this situation to support by mixing type and displacement sys response to the re,ader interest ex an analytical method. CFD also lends tems. Displacement ventilation usually pressed after publication, this article discusses the design procedure for the most commonly used type of system, Convection plume Return termed "passive thermal displace ment ventilation." ,,- ,'-.\ Upperzo!e With passive thermal displacement \ �/��-�-· ,... � � ventilation, supply air is discharged ---- =- = -\ t-t-fJ .t__ -StFatification level ::- / directly into the occupied zone at low / \ velocity near the floor level and at a ..,\ t t I \._ / \ slightly cooler temperature than the I Lower zone design room temperature. The air Supply t from the diffusers spreads along the :;) � floor, creating a relatively cool layer of fresh air near the floor. Heat sources within the room (people, pro Heat and contaminant source cess equipment, etc.) create thermal plumes of rising air that entrain this FIGURE 1. Schematic of a passive-thermal-displacement-ventilation system. air and carry it up past the human-in halation zone and eventually up near itself to large rooms since the dimen is preferable where: the ceiling. The warm, contaminated sions are too large for full-scale mea • Contaminants are released in combi air forms a stratified region in the up surements and because the design of nation with surplus heat. per zone of the room, which is ex ten is unconventional. • Contaminated air is warmer and/or hausted fromhigh-level air returns. The use of CFD codes for practical lighter than the surrounding air. This stratification of contaminant -three-dimensional computation re • Supply air is cooler than the ambi levels makes it possible to provide quires expertise, experience, and ent air. higher-quality air in the occupant computational power that usually is • Room height is more than 9 .8 ft._ breathing zone without increases in unavaila�le to typical designers. Be • Cooling load through the air supply - system or operating cost. In 1997, the sides, the prediction of velocities and does not exceed 12.7 Btuh per sq ft for authors reviewed and analyzed the temperatures in rooms with displace commercial spaces and 25.4 Btuh per sq published data on the design and de ment ventilation using CFD codes ftfor industrial spaces with moderate ac velopment of passive-thermal-dis generally is inaccurate. tivity levels when regular displacement 2 placement-ventilation systems. This article presents design guide- ventilation air diffusers are used. With
HPAC Heating/Piping/AirConditioning Engineering• November 2000 39 DISPLACEMENT VENTILATION
induction-type air diffusers, these loads TABLE 1. Coefficient t/; can be increased to 19 Btuh per sq ft and Source surface temperature, c 31.7 Btuh per sq ft,respec tively. € 40 50 60 100 150 200 300 500 800 1000 1200 • Mechanical disturbances are minor. 0.42 0.44 0.48 0.1 0.8 0.45 0.45 0.4 0.32 0. 2 0. f 0 • There is room for air diffusers in the 0.52 0.55 0.58 0.59 0.56 0:51 0.42 0.29 0.14 0.1 occupied zone. 0.5 0. 0.2 0.13 0.76 0.77 0.78 0.76 0.73 0.65 0.59 0.3 0.2 0.14 DESIGN PRINCIPLES Supply-air diffusers are located at or on room surfaces that are heated as a Heat sources near the floor level,with the supply air result of heat radiation from primary The total heat load (W0) is intro introduced directly to the occupied heat sources. Radiant heat exchange duced by each source by convection zone. Returns are located at or close to occurs between heated and unheated (Wconv) and radiation (Wrad).4 This re the ceiling, through which the warm surfaces and results in the redistribu lationship can be described by the fol room air is exhausted from the room. tion of heat flow. As a rule, the inten lowing equation :
The supply air is spread over the floor sity of heating air with secondary Wo= Wconv + Wrnd = t)!Wo = (1-t)i) Wa and rises as it is heated by the heat sources is low, with no stable thermal (1) sources in the occupied zone. plumes created above them. The heat The total radiant component (Wrad) Heat sources in the occupied zone from the secondary heat sources is of the heat load introduced by each release heat by convection and radia transferred to the air of the lower tion. Convective heat warms the air zone. If the primary heat sources TABLE 2. Coefficient ({)horizontal adjacent to the source; this air moves in the room are not intense 8/H upward in thermal plumes. Radiant enough or if their surface area is Source location in the room 1 2 3 4 heat warms up the colder surfaces of evenly distributed through the 0.3 0.12 0.04 0 the room, which become secondary room (e.g., a heated floor or spec Along room axis heat sources. tators sitting close to each other) Between axis and wall 0.38 0.17 0.11 0.07 The air volume of the thermal or all sources of heat are located Close to wall 051 0;3 0:3 0.16 plumes increases as the plumes rise be in the upper zone, no stable ther cause the plumes entrain ambient air. mal plumes will form. The con TABLE 3. oefficient cp vertica1 A stratification level develops where vective heat fromthese sources is C 8/H the air-flow rate 'in the plumes equals assimilated by the supply air in Source location 1 2 3 4 the supply-air-flow rate. Thus, two dis the occupied zone. The supply air in the room : tinct zones are formed within the room: is heated while flooding the lower Along room axis 0.8 0.7 0.65 ,0.6 (1) the lower zone below the stratifica zone due to the convective heat Between axis and wall 0.8 0.12 0.67 0.63, tion level with no air recirculation from and is forced intothe upper zone Close to wall 0.85 0.75 0.7 0;68 the upper zone and (2) the upper zone, by the cooler supply air. where the upward thermal plume en trains only the recirculated air fromthe upper zone (Figure 1). Thermal plumes a z serve as natural channels by which con vective heat and contaminants are transferred from the lower zone to the Main zone upper zone. The height of the lower zone depends on the supply-air-flow Acceleration zone· rate and characteristics of heat sources and their distribution across the floor Transition zone area. Some researchers and practition ers recommend that displacement-ven ti lation systems be designed so the lower zone is higher than the occupants and the occupied zone can be venti 'A lated effectiv�ly. Others allow the strat ification level to be lower than the breathing-zone level, taking into ac count research data showing that fresh - air reaches the inhalationwne frombe FIGURE 2. Convection flowabove a heat source. Notes: Zs, distance from the source low with a plume created around the surface to the virtual source; Z. distance from the source surface to the convection flow person's body, cross-section of interest; a, convection flowschematic; b, boundarylayer. Reproduced Secondary heat sources are formed courtesy of Elterman, 1980.
40 November 2000 • HPAC Heating/Piping/AirConditioning Engineering
DISPLACEMENT VENTILATION
source into the space can be divided the heat load introduced by each tjJ = the portion of the convective between the upper (Wrad up) and the source: component of the total heat load re lower or occupied (Wrad Low) zones of Wconv = Wconvlow + Wconvup = 13tVWo + leased into the space. this space: (1-13)tjJWa cp =the portion of the radiant compo Wrad = Wradlow + W rad up= cp (1-tjJ)Wo + (3) nent of the total radiant heat load in the
(1-cp) (1-1)1)w 0 where: low zone. (2) tjJ, cp and 13are non-dimensional coef 13 = the portion of the convective The total convective component of ficients. component of the total convective heat load in the low zone. CoefficientstjJ, cp, and 13vary within a range of 0 to 1. The value of coefficient tjJ depends on the heated surface tem perature, while emitance (e) and can be estimated from Table 1. The value of coefficientcp depends on the source location in the ventilated room (e.g., in the center, close to the wall, etc.) and the source dimensions relative to the room size. Coefficient cp values for horizontal (cphori•onrat)and ver tical ( 'Pverticat)surfaces of small sources (less than Xo of the room size) can be es timated using tables 2 and 3. In tables 2 and 3, 'Phor1.anra1 and 'Pverti cat are related to horizontal and vertical surfaces. Examples of coefficients tjJ and cp for some typical heat sources are: Insulation can sometimes be an afterthought. .. that is • A sitting or standing person, until a failure occurs. You can pay dearly for insulation tjJ= 0.57; cp = 0.63. • Machining equipment, tjJ = 0.5; failures in increased maintenance. and replacement costs, cp = 0.6. corrosion damage to piping and equipment-and 13 coefficient values depend on the
air-supply method (e.g., f3 = 0 with dis failures that can shut down your operation. placement and natural ventilation; 13 = 1 with convective plumes dissipating within the occupied zone due to inter Users of FOAM GLAS® cellular glass insulation benefit action with supply jets, air flows cre from more than 60 years of proven "in-the-field" ated by moving objects, etc.). Thermal plumes performance, industry-leading technical support, a Empirical, analytical, and CFD are the commonly used approaches for world-class testing lab, and the industry's best evaluating air-flow rates in thermal fabrication and distribution network. plumes created above people, lights, hot surfaces of process equipment, and other objects with a surface tempera Call us today. Learn how we can solve your insulation ture greater than the room air tempera ture. Information on air-flow rates in problems before they occur. thermal plumes is essential for design ing displacement-ventilation systems. - Many design procedures for dis PITISBURGH CORNING placement ventilation recommend cal culating air-flow rates in thermal plumes using equations derived forso FOAMGLASI I I I L At I 8 I called "point" and "linear" sources. In www.foamglaslnsulation.com reality, heat sources are seldom a point, 1 ·800-359-8433 a line, or a plane vertical surface. The most common approach to accounting
Circle 326 on Card; see HPAC lnfo-dex, p. 63 42 November 2000 • HPAC Heating/Piping/AirConditioning Engineering I
for the real source dimensions is to use method is how to estimate the location above the point source passes through e a virtual source from which the air of the virtual located point source. the cop edge of the real source (e.g., 5 6 8 flowrates are calculated4' ' '7' (Figure The method of a "maximum cylinder) . The "minim um case" is 2). The virtual origin is located along case" and a "minimum case" provides a when the diameter of of 8 vena concracta the plume axis at a distance (Zo) on the tool for such estimation (Figure 3). the plume is about 80 percent of the other side of the real source surface. According to the "maximum case," the upp r surface diameter and is located The adjustment of the point-source real source is replaced by the point approximately Yi of that diameter t model to the realistic sources using the source so the border of the plume above the source. The spreading angle virtual-source method gives a reason
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b. Minimum case
FIGURE 3. Convection flowabove a vertical cylinder. Reproduced courtesyof Skistad, 1994. MEE INDUSTRIES INC. Circle on Card; see HPAC111 lnfo-dex,r--- 327 p. 56 HPAC Heating/Piping/AirConditioning Engineering• November 2000 43 DISPLACEMENT VENTILATION
TABLE 4. Air-flow rates in convective plumes above typical heat sources in restaurants (@tit!H = 0) Source size, m Height above the bottom of source, m Source Source 0.1 0.2 0.5 0.75 1.0 1.5 2.0 2.5 3.0 No. characteristic A s· H strength, W 1 10 2 25 42 62 87 111 Person sitting IJ.-=0.3 1.3 4 it 18 2 Person standing fJ= 0.3 1.8 105 2 4 1Z 19 38 61 81 95 118 3 TV 0.66 0.66 0.66 300 7 14 39 63 89 137 180 229 218 0 0.46 0.3 500 6 1 36 51 10 121 188 264 332 4 Cash register .46 3 5 Bottle box 0.1 0.76 0.71 770 8 15 33 52 74 132 212 320 448 6 Mug chiller 1.2 0.76 0.71 830 11 22 53 84 124 181 248 335 448 6 Ice cream cab. 0.46 0.6 0.9 360 5 12 25 38 54 92 142 210 275 fJ=0.15 0.1 100 13 15 23 30 40 12 117 164 204 8 Hanging lamp
TABLE 5. Air-flowrates in convectiveplumes above typical heat sources in restaurants (@fit!H= 0.5 C/m) Source size, m Height above the bottom of source, m Source Source 0.1 0.2 0.5 . 0.75 1.0 1.5 2.0 2.5 3.0 No. characteristic A 8 H strength, W 1 Person sitting fJ=0.3 '1.3 10 2 4 11 15 18 26 32 4e 26 2 Person standing fl=0.3 1.8 105 2 4 11 13 113 28 36 39 42 3 TV Q.66 0.66 0.66 300 5 10 .31 41 61 85 114 142 161 OA6 0.46 0 3 500 6 13 36 5.1 83 106 134 168 4 Cash register . 69 5 Bottle box 0.1 0.76 0.11 710 8 15 33 48 70 104 162 200 241 0.76 0.11 830 11 22 53 124 169 190 195 215 6 Mug chiller 1.2 - 84 • 0. 0.6 360 5 11 25 38 54 72 92 111 129 6 Ice cream cab. 46 o.9 Hanging lamp fJ=0.15 0.1 100 1 9 14 22 28 42 50 54 39 8 .
TABLE 6. Air-flowrates in convective plumes above typical heat sources in restaurants (@!it/H= 1.0 C!m) Source size, m Height above the bottom of source, m Source Source 0.1 0;2 U.5 0.75 1.0 1.5· 2.0 2.5 3_,o No. characteristic A 8 'H strength, W 1 70 '" 4 15 1B 21 20 26 Person sitting ff=0.3 1.-3 2 11 20 2 Person standing f1= 0:3 1.8 105 2 4 111 114 1 0 22 22 13. ,_. 7 2 3 TV Oi66 0.66 0.66 300 5 10 3,7 45 57 71 85 94 102 OA6' 0.46 0.3 500 6 13 51 52 70 124 4 Cash register 36 84 111 5 Bottle box 0.1 0.7.6 0.11 170 8 15 33 48 65 100 121 149 166 1.2 0.76 0.71 830 22 53 84 104 121 148 153 156 6 Mug chiller 1'1 6 Ice cream cab. 0.46 0.6' 0:9 360 5 11 25 35 41 61 73 71 74· fJ = 0.15 0.1 100 1 9 13 23 32 9 - 8 Hanging lamp 17 32
TABLE 7. Air-flowrates in convective plumes above typical heat sources in restaurants (@tit/H= 2.0 C/m) Source size, m Height above the bottom of source, m Source Source 0.1 0.2 0.5 0;75 1.0 1.!f 2.0 2.5 3.0 No. characteristic A 8 H strength, W 7 1 . 10 3 9 - . Person sitting 9=- 1 1'4 ·9 0.3 1..3 7 12 ' - 2 Person standing ff=0.3 1.8 105 i a .q� 10 14- 11,6 j,7 5 '1 3 - 01Q6 0.66 0.66 300 6 11 54 55 52 47 TV as 46- 7 J 0.46 0.46 500 6 13 51 68 66 45 - 4 Cash register '0.3 36 7 5 Bottle box -0.1 0.16 0.11 710 8 15 3J 41 59 90 101 99 69 - - . 6 Mug chiller 1. 2 0.16 0.71 830 11 22 53 61 100 99 78 55 25 6 Ice cream cab. 0.46 0.6 0.9 360 5 10 23 30 39 50 49 38 34 f!=0.15 0.1 100 1 9 13 16 21 18 - - - 8 Hanging lamp
44 November 2000 • HPAC Heating/Piping/AirConditioning Engineering of the plume is set to 25. For low-temperature sources, the 1.1 mor1.8 m) and the ankle level (hooo,= 0.1 m) is limited "maximum case" is recommended, whereas the "minimum for the comfort reason by 2-3 C. This results in restriction of l:ase" best fits the measurements for larger, high-temperature temper gradient (At/H = air temperature differencebetween the floor Step2: Calculate the average convective heat component and the ceiling levels over the room height) on air-flow rate ( lji) using the data for the individual heat sources: I in the thermal plume is illustrated in tables 4, 5, 6, and 7 for � 9 2.:( 1 '¥1) heat sources typical for dining areas in restaurants. W x (4) lfF = r,w. ) INPUT DATA Step 3: C�lculate the averaged radiant heat component i The following data are required for system design: into the occupied zone ( - contaminant concentration in the breathing zone Step 5: Select the supply-air-temperature difference, At0 = J (mg/m ). t0,-t0 (approximately 3 C), based on the air diffuser's perfor •Cooling load due to heat losses/gains through the building mance data, the type of human activity, and the distance be 2 envelope (Wext, W/m ). tween the air diffuser and the nearest person. • Minimum air-flow rate to be supplied into the space. Step 6: Calculate the preliminary value of the supply-air flow rate (G0" kg/h) required for heat removal, using Kt= DESIGN PROCEDURE 0.5 K'° for the first iteration: There are four primary assumptions for a displacement W G = I, , ventilation-design procedure for rooms with primarily heat at (7) C �toK, removal requirements. They are: r 71) • Temperature stratification is a linear function (there is no Step 7: Calculate the adjusted heat-removal coefficient, *· step stratification as there is with a contaminant-concentra K ' . tion distribution), At= ( texh - tnom)/Hrnom· Heat balances and radiant and turbulent heat exchange are calculated for two zones: the lower-zone limited by the height of the occupied (8) zone and the upper zone above the occupied zone. • Occupied-zone temperature is the air temperature at the height of h0.-that is, 3.6 ft for spaces with a predominant - where: seating activity and 5.9 ft for spaces with a standing activity. = Occupied-zone temperature ar these heights is considered to a,.,b ( -1) K · 2 be the same throughout the occupied-zone area outside the g At (H ) + 0 ' 3 .3 __ � room -h o.z. direct influence of the supply-air flow. 1 (H�. ) ( dV ) T"., -h., lt.s (g) •The temperature difference between the head level (ho, = ( HPAC Heating/Piping/AirConditioning Engineering • November 2000 45 :r;, ,, ---*1}"1, , : ·----- DISPLACEMENT VENTILATION To simplify the K, coefficient evaluation, the following ( - -2. l+A K=l+0.16 G0 x l-tp Atp) 87 x procedure can be used: H Hroon, toom • Obtain using the graph in Figure 4. 1 + 2 1 + 2 A 1A: �A,oom • Calculate: K = F1 - Fi, where F1 and Fi can be obtained us ing graphs in Figure 5. (10) l - 1 I ) 1- )-17 K, a 0.1 0.2 0.3 0.4 0.5 1- <:::'... """" ...... ><::""'-.. """'- ...... ""...... 4;8 0:30 ...... 1 ...... b -- · - 4:6 - - ...... ::....,__ __ "'" ...... ' " .... 4.4 \ 0.25 ...... 1 "'- ...... "' !'...... 4.2 " ...... , '- " ' 1"- " \ 4.0 0,20 ' ,, " ' ' " "\. \\ '1'= 3.8 : 0.65, I\\. ,,r 3.6 'I' = 0.6 :--..: .... "\\. \ \. ,_.,,.. I 3.4 \.\.. \.. \.. A.c0.1 -- I 'l' •0.55' " / 'i'•0.5 " 3:2 _\. \..'\. r-..'\. - / �"',,, .,., 7 F2 v ;., .. 0.2 - ,.. 3,0 \.'\. '\... "'\... ).: .3 -- = 25 / 0 I"/ Go/Hroom '1' · I .45•> 2.8 \.. \... """' / 0 / t ���� ""-r - I - 2.6 ·"- ,.._""';;:., , I// .. 'j�iv�. :.= :r"- - '/'1l, •• Q.40.5 -- / 2.4 , � "'-'--' /I/// '/ A.•0.6 - .� ,.,. -.:" ,·I .....J I 2.2 ...... r--.:..-...... _//I/// / / 50 "-. '-...... Go/Hroom= ,�•- i -t,..:1,;::'.'4 f "--,- ""'� Go/H,....:]� ...... !'-... � ...... <...::'./'�./ / I <�:r.: ' -- -r 2.0 ...... 1.8 ...... � ...... /') ::2"-..::'.r--. � --- � ----+-::100 1.6 ...... r--. � -=- "') ...... �� ·:--:.''I;.�--- Go/Hroom = -...... : -- -.....;:...... : --= / / •,.9_2��' � _ ,..1 . - - 1.4 . -�...... -- -- ��-,- - l 1.2 L.'.1� 1.0 ----....;; �( I - - I I - � u u M U � V M M 1.0 1.2 1.4 1,6 1,8 2.0 2.2 2.4 2.6 2.8 3.0 fi-tiol"Ar Kt FIGURE 4. Graph for parameter A evaluation. FIGURE 5. Supporting graphs for K = F1-F2 evaluation: a-F1, b-F2. 46 November 2000 • HPAC HeatingfPiping/AirConditioning Engineering Iii Clturb • Obtain aturb using graphs in Figure 6. • Obtain K, using graphs in Figure 7. 0 5 10 IS 20 r Step 8: Compare K, *,calculated using Equation 8 or graphs Ill I I • '""' . 1.,. t, = 3.5, ,_.,...... _,_ ...... ____ _...... , ______'""' in figures 4 through 7, with K, calculated as0. 5 K0• l I Y'f -aii 1 Ml' 1,.-1H·h0,=115 +-H-++++-HH-++�7 f-:+-+++++-H'--I H·hoz = 2 .... :!:] � � I II II II 1-tiO\lbtt"'"''"'" H· 2 5 «" 0.6 h0, = +-H-+-++--!:>of''.... :+- +-+-H- t,, - t0 = 3 ,....if � r � _,. -1-,_.--b"""'i--H :{ "'Q ��- -��· H-h0z=:3 "' "' "':{ -� = ....,H -h,, 3.5 +-H"""....9-+- +-HH-+-++....:i... 1"9,....-+-++-+-H--! .. fJf!- .., 7 ""' �3.5 - �,... ,, ·- .... -- .. ·� K·3-- " ... �"'25- 5 H-+++,>,'*<-!"1:::1"""-'r=T-+-t-i-1-t-++++-I-+r., 2 -+,_-t_-::::1;.,..."t'"'I ,... ·lo,• ,.... K • 2'-- , ,.... , -� , [\;;,1.S.- ... 3 ,, � � ... = 1-- 2 1-1_:--_ - - - ,.... 1/K�- 0.1--i' 1., - t, = 1 !Kio"= 0.3 1-+-l-+-+--+-+-+-;;-+-+--+-+-r+-;1-!--+-+--+-+-+- -+-+-+-l-+-i 1/Kcq. m2::2- l/1<10"Q.d I - 2.25 0 1.75 a.}5 3 3:75 0 3 5 8 FIGURE 6. Graph for parameter aw,b evaluation. FIGURE 7. Graph for heat-removal-coefficientK, evaluation. Controts ...... The ext Generation Is •RECIPROCATING CHILLERS thermostats to the most advanced •SCROLL COMPRESSOR CHILLERS programmable controllers ... 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North America: DGH Systems, L.LC. 1834 Freedom' Road, Lancaster, PA 17601, Phone: 717-293-521 O - Fax: 717-293-0449 - e-mail: [email protected] Europe: CAREL srt Via dell'lndustria, 11 ,. 3�o1io.eJ!JQl�e. (Padova) Italy - Phone: +39,049,9716611 Fax: +39.049.9716600 ·e-mail: [email protected] HPAC Heatfng/Plping/AlrConditlonlng Engineering • November 2000 47 If 1111 . DISPLACEMENT VENTHILATION If (Kr* -K,)/K,* is less than 0.1, pro 7) Mundt, E.1992. Convection Flows inRoom s with Temperature Gradients; Theory and Mea ceed starting with Step 8. If (K,* - 0.1, surements. ROOMVENT'92. Proceedings of the K,)/K,* is greater than assume K, = Third InternationalConference on Air Distribution in K,* and repeat the calculations in Rooms. Vol. 3. Aalborg. Step 8. REFERENCES 8) Skistad, H. 1994. Displacement Ventilation. Research Studies Press, John Wiley Sons Ltd., Step 9: Calculate the exhausted-air 1) Zhivov, A.M., P.V. Nielsen, G.L Riskowski & West Sussex. UK. K, and Eu. 0. Shilkrot. 2000. Displacement Ventila temperature (texh = ta+ Lita). 9) Aksenov, A.A., A.V. Gudzovski, Eu.O. 10: tion for Industrial Applications: Types, applica Step Calculate the supply-air tions and design s"trategy. HPAC Engineering. Shilkrot and A.M. Zhivov. 1998. Thermal plumes temperature ( ta), given the occupied March 2000. above heat sources in rooms with a temperature stratification. Proceedings of the 6th International zone temperature ta, 2) Zhivov, A.M., Eu. 0. Shilkrot, P.V. Nielsen and G.L. Riskowski. 1997. Displacement Ventila Conference on Air Distribution in Rooms "Roomvent (13) tion Design. Proceedings of the 5th International '98."Volume l. Stockholm. Symposium on Ventilation for Contaminant Control. 10) Shilkrot, E.O. and A.M. Zhivov. 1996. "Ventilation '97 ."Vol. 1. Ottawa, Canada. Zonal model for displacement ventilation design. Step 11: Calculate the temperature 3) Zhivov, A.M., G.L. Riskowski, T.W. "ROOMVENT'96." Proceedings of the 5th Interna Conference on Air Distribution in Rooms. V.2. gradient ( At/H) along the room Ruprecht, LL.Christianson, P.V. Nielsen, Eu. 0. tional Shilkrot and A.A. Rymkevich. 1995. Design Yokohama, Japan. • height: 1) Guide for Displacement Ventilation. Research �t0(K, - Project Philip Morris Management Corp. Inter t exh -t a.2. for t J _ -�---'- � H ='= national Air Technologies Inc. Savoy, Illinois, In the second part of this two-part series, to U.S.A., 145 pp. appear in a future issue of HPAC Engineering, (14) 4) Designer's Guide. 1978. Ventilation and Air the authors will detail the displacement-ventila Conditioning. Chapter 5. InternalSanitary-Tech If .'.it/His greater than the prescribed tion-design. procedure for rooms with heat- and nique Units. Part 3, Book 1. Moscow: Stroiizdat. one to achieve thermal comfort, de DGB. 2001. Industrial Ventilation Design Guide contaminant-removal requirements and discuss ,, crease Lita and repeat calculations book. Chapter 7. Academic Press. air-diffuser selection and location considerations. starting with Step 6. 5) Elterrnan, V.M. 1980. Ventilation of Chem Also, they will include a case study demonstrating ical Plants. Moscow: KHIMIA. Step 12: Calculate supply-air-flow the proper use of design procedure presented in 6) Holman,J.P.1989. Heat Transfer. McGraw the · rate (Ga) required for heat removal, Hill Book Co. Singapore. this series. 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