units). The factors that inluence space comfort

Radiation Conduction Convection Evaporation units). The factors that inluence space comfort Local Air Velocity, FPM Local Air Velocity, FPM 1 1 8 6 4 2 8 6 4 2 4% Neck region 3% 2% 1% 2% 1% 3% -6-4 -2 2 4 Feeling of coolness Ankle region Feeling of warmth -6-4 -2 2 4 Local Air Temp. minus Ambient Temp. (T X - T A ) 4% Feeling of warmth Feeling of coolness Local Air Temp. minus Ambient Temp. (T X - T A ) D

1 8 6 4 2 Neck region 2% 1% 3% = -3F = +2F 4% Feeling of warmth Feeling of coolness -6-4 -2 2 4 Local Air Temp. minus Ambient, F (t X - t C ) used to rate a system in the ield. It will also be covered

Predicted Percentage of Dissatisied (PPD) at each Partial Pressure, Millibars.8.5.3. 5 Executive & Clerical Executive 55 6 65 7 75 8 85 Temperature, º F. Met Rate = 1 (Typical for ofice) Air Speed = 2 (Typical interior ofice) Air Speed = 2 (Typical interior ofice) 8% Clerical 6% 5% 4% % RH 2% 1% effectively overcome stratiication zones created by the replacing NC in the ASHRAE Handbook, most speciications Signiicantly closed balancing dampers can add

signiicantly closed. D D D D t D Selection by supply jet mapping identiies the most probable Not all applications result in overblow in a conined Select type of diffuser (Reviewing the Classiication When selecting a side wall grille, check coniguration ADPI 1 8 6 4 2 High Sidewall = 2 BTUH/Sq.Ft. = 4 BTUH/Sq.Ft. 4 Light Troffer Diffusers.5 1. 1.5 2. 2.5 3. 3.5 4. T 5 /L Round Ceiling Diffusers 12 Two Slot Diffuser

ield tests see ADPI topic, selecting a side wall grille, check coniguration in system, this must be done for both maximum low rate (maximum load) and at the lowest low rate expected the minimum low shown in the building plans.)

induction rate of the air diffusion device at higher lows, temperature as the low rate decreases. I II cfm, discharge area and velocity proile. Isovel testing has Zone III IV PRIMARY AIR Total air High velocity 22 Induced room air gentle movement Greatest possible source of drafts deine the jet. These zones are shown in the dimensionless calculate the throw for a diffuser at any low condition. (The deine the characteristics of each zone is shown below. In the irst zone, the jet maintains a constant velocity with Where Q = outlet low rate A

A 1. Decreasing Zone I K 3 Zone II TYPICAL LINEAR 15 1 V x /V o Zone III o Zone IV 5 X/ A Increasing A C = entrainment coeficient, 1.4 for ininite

Isothermal 5 6 8 1 12 15 2 3 25 Feet 3 T 1 T 5 T 15 2 15 1 5 24' T 15 5 Isovel 14" x 4" 15 cfm Velocity Measurements 15 cfm 3 cfm Throw T 15, T 1, T 5 5 9' Isothermal and Cooling 24' 2 15 1 5 T 15 T 5 T 1 T 15 T 1 9' T 5 Isothermal & 2 F Cooling 15 cfm Velocity Measurements 3 cfm Throw T 15, T 1, T 5 attach the jet low to the ceiling or surface. (The higher As the jet lows along a surface, secondary room air can no

vs. x / A BD Two outlets handling the same opposing airlow values would result in airlow in the space like that shown for one higher airlow is also an example of Rolling the Room, shown in the section on Classiication of Supply Outlets, differential, a modiication of a similar method proposed The most signiicant results are shown in these igures with conigurations. These charts show the relationship of cfm, the same size outlet under these conigurations handling

The following igures show the effect of buoyancy on drop Drop, Ft. 5 1 15 2 1 1 cfm 2 4 6 8 1 3 JET VELOCITY on delection angle and ceiling effect. The igures below on the igures (or the same intercept of cfm and velocity) represent a single outlet using varying conigurations. 15 2 3 Throw, Ft. TYPICAL 1 ENVELOPE 2 cfm 5 1 JET VELOCITY 4 7 5 TYPICAL 1 ENVELOPE Drop, Ft. 5 1 15 1 cfm 2 4 6 8 1 15 2 cfm 1 7 5 15 JET VELOCITY 2 1 3 JET VELOCITY 2 3 Throw, Ft. 4 5 Delection settings and resulting patterns are shown on, divide the lowrate by the effective area.

TYPICAL 1 ENVELOPE Drop, Ft. 5 1 15 2 1 2 4 6 3 JET VELOCITY 8 1 15 1 cfm 2 cfm 2 3 Throw, Ft. 5 15 JET VELOCITY 1 7 4 5 TYPICAL 1 ENVELOPE Drop, Ft. 5 1 15 4 2 1 3 JET VELOCITY 1 cfm 6 2 8 1 15 2 cfm 5 1 7 15 JET VELOCITY 2 3 Throw, Ft. 4 5 Delection settings and resulting patterns are shown on, divide the lowrate by the effective area.

Drop, Ft. 5 1 15 1 2 4 6 3 JET VELOCITY 8 1 2 cfm TYPICAL 1 ENVELOPE 5 1 2 3 4 Throw, Ft. 15 JET VELOCITY 1 7 5 TYPICAL 1 ENVELOPE 1 Drop, Ft. 5 1 2 4 6 3 JET VELOCITY 8 1 2 cfm 5 7 15 JET VELOCITY 1 15 1 2 3 Throw, Ft. 4 5 Delection settings and resulting patterns, divide the lowrate by the effective area.

horizontal airlow along the ceiling, the drop can be related. In these cases airlow less than maximum shown results Supply Outlet Classiications principle of analyzing the airlow into the space from some on through today, the principles of stratiication, natural From these results, some general outlet classiications appear. These classiications may be used in the irst of system. The following igures will classify the outlets by The magnitude of the stratiication zones and gradients is representative of each type of outlet in a speciic space the gradient curve in the stratiication zone for all outlets is only the size of the stratiication zone is changed by the type temperature gradient and size of the stratiication zone were increase in airlow rate or supply velocity. These conditions stratiication zones, and temperature differentials were compared between different conigurations. deined as the mixture of air supplied to the outlet and deined by high velocity isovels taken through two Total air is deined as the mixture of primary and room primary and total air envelopes) which is under the inluence relatively high velocity but it has no sharply deined lower

COOLING HEATING Inside wall STEP 1 Primary air STEP 2 Total air STEP 3 Natural convection currents and stratification zone Outlet Exposed wall STEP 4 Return intake Intake Intake 9' Ceiling 6' Intake 4' STEP 5 Room air Intake 9' Ceiling 6' 4' Height Average Room Vertical Temperatures Temperature Setpoint - + Temperature, F - + Temperature, F

Supply Outlet Classiications (continued) of the walls and ceiling in a thin ilm. The occupied space Since the total air within a conined space is affected by Stratiication layers as shown in ( identiied by a region where a layer of smoke will hang for some time. Whether a stratiication layer actually exists is not important, but the concept of a stratiication layer and stratiication zone leads to a better understanding of air mixing zone between the stratiication layer and the ceiling during cooling and between the stratiication layer and the loor during heating. total air and stratiication layer. The lowest air motion is in the stratiication zone. uniform (between the total air and the stratiication layer), the stratiication layer is crossed, the temperatures in the neutral zone vary considerably. Gradients in the stratiication zones show that the air is stratiied in layers of increasing Since the stratiication zone depends primarily on natural low, and with minimum internal loads. With no loading, Classiication of Supply Outlets ), showed different conigurations and

A Plan View A High side wall Side View Section A-A Section A-A COOLING HEATING Setpoint Setpoint - + Temperature, F - + Temperature, F Total air will follow the wall down to loor level if its projection is suficiently long. During heating, this will result in a smaller stratiication zone and lower temperature at the loor. The two airstreams project into and down the Side View COOLING Plan Plan View A A Outlet Ceiling Section A-A HEATING Setpoint Setpoint - + Temperature, F Section A-A - + Temperature, F that this pattern is most eficient for cooling in spaces such as open ofice areas. generate very uniform temperatures. The inluence of

Supply Outlet Classiications (continued) CIRCULAR FLOW PLAN VIEWS CROSSFLOW CEILING DIFFUSERS SIDE WALL GRILLES ELEVATION VIEWS PLAN VIEWS ELEVATION VIEWS 45 Deflection See Fig. 17 Deflection See Fig. 13 LINEAR TBD WITH SPREAD PLAN VIEWS ELEVATION VIEWS Low Flow Rate Short Throw High Flow Rate Long Throw With ceiling diffusers, we must consider the different airlow for linear diffusers, typically exhibit low in one of two patterns: circular or cross low. The diagrams in ( crosslow patterns. cross low pattern. The vertical diagram shows that during Cross low patterns with longer throw and individual side end of the throw, cross low patterns will continue in the dependent only on the airlow from each diffuser side. Both greater change in airlow during VAV. A crosslow pattern

Supply Outlet Classications (continued) Comparing the plan views of the circular and cross low throw than the cross low for a given low rate. The cross low jet projection continues after the low terminal velocity just like the airlow from side wall registers at delection. During cooling, the circular recirculating airlow results in less drop than with cross low jets. The wide spreading 45 delection from the side wall The delection grille is a pattern followed by all single airlow is reduced. midpoint of the recommended range for the speciic outlet. This will result in maximum constant airlow characteristics. (occupied) low rates. VAV systems can vary the air delivered to the space, and range. Minimum lows listed on building plans are often below that expected to be experienced when a space is occupied, so higher and more realistic lows of limiting the variation in throw to a minimum with the variation in low rate should occur with the minimum airlow should be approximately 5 to maintain mixing at the diffuser. At maximum low, the diffuser should be satisfy occupants where at high load (and high lows) when the space will be at maximum airlow. Except for maximum load conditions, the VAV airlow will maintained with airlow rates from maximum to less than 7% of maximum. airlow change in the variable air volume system. The results indicate that problems are more likely to exist at high airlow rates. A simple rule to follow: Select the combination of outlets and maximum airlow rate to avoid high air velocities in the occupied space. Lower airlow rates will be acceptable. High air velocities occur when the total air enters the provide an ADPI of 1% in open ofice areas over a broad range of loads and airlows,

Supply Outlet Classiications (continued) indicates a laminar low outlet. This type of an outlet is the opposite of the turbulent low derived from a conventional mixing diffuser. Laminar low implies lines of vertical direction. A laminar low outlet must have relatively airlow below the outlet produces uniform velocities to of throw do not apply in this case. Laminar low does not LAMINAR FLOW Side View Side View COOLING HEATING Setpoint - + Temperature, F Setpoint - + Temperature, F HEMISPHERICAL FLOW are not recommended as the airlow becomes unstable During cooling the air will often be projected to the loor. A stratiication zone can be formed near the ceiling, stratiication layer. The size of the stratiication zone will system that reduces the low will allow a larger stratiication stratiication where air must be introduced from the ceiling. machinery by projection to the loor near the machines with controlled by projecting more or less air to the loor level, providing more air to the loor if the main heat source is at the loor level. projection, spread and buoyancy. The loor level becomes cooler and a stratiication layer can form. Heat sources near the loor or the air projected all the way to the loor helps to reduce the neutral zone. Return intakes located at the loor in stratiication zones will help. indicates a hemispherical vertical low from the low unit. Vertical projections from these diffusers will not be as stable as those obtained from a laminar low diffuser diffuser to cause the airlow to increase toward the outside.

Supply Outlet Classiications (continued) 1 15 2 located below the ceiling, will irst project upward toward JET VELOCITY 3 4 6 8 1 24 2 16 14 12 1 8 6 4 3 25 2 Flow Rate, cfm 15 2 3 4 5 DOWNWARD VERTICAL PROJECTION, FT. 5 12 8 55 5 4 35 9 5 7 45 12 35 8 45 4 3 6 4 3 1 7 55 35 25 9 5 35 6 3 25 8 45 3 2 5 7 4 25 2 45 35 25 6 4 2 15 55 3 35 2 15 5 12 45 25 3 15 12 4 15 1 35 25 2 1 12 9 9 3 12 8 2 1 8 15 7 25 1 9 7 9 8 6 15 12 6 2 8 7 5 18 1 7 12 6 5 9 15 6 4 8 45 1 5 7 12 4 3 8 1 2 3 4 5 2 HEATING COOLING ISOTHERMAL TEMP. DIFFERENTIAL Cross low pattern diffusers are not capable of causing the airlow to go upward when set for a horizontal pattern On the other hand, a cross low pattern diffuser generally cross low jet pattern and with the velocities can be spread 6" 12" TDC with 9x9 neck, 4-way pattern and 24 cfm 3" Ceiling 3" 16 3 3"

Supply Outlet Classiications (continued) matches the actual deinition given for displacement ventilation. Deined as a low velocity, low temperature differential air distribution across the loor level, above a stratiication level. The stratiication level usually horizontal projection at loor level. This performance level Convection plume Return Upper zone Setpoint Lower zone Supply Heat/contaminant source Temperature, F Plan View Side View COOLING Setpoint Section A-A - + Temperature, F HEATING Setpoint A A Plan near floor Baseboard Section A-A - + Temperature, F Spreading horizontal projection at loor level permits considerable stratiication at high levels during cooling while

Supply Outlet Classiications (continued) the loor with a spreading jet. Natural convection currents A stratiication zone forms above the natural convection A opposite wall. The room temperature above the stratiication stratiication layer. This was also the case in ( Side View Section A-A COOLING HEATING Setpoint - + Temperature, F Side View A Floor diffuser Section A-A Setpoint - + Temperature, F Side View COOLING Side View COOLING HEATING Setpoint Setpoint - + Temperature, F - + Temperature, F

Supply Outlet Classiications (continued) When using loor or low level air distribution at the perimeter, stratiication from the loor can be controlled Complete stratiication across the room can occur as shown project to the ceiling. The stratiication can be minimized by stratiication will occur above that level. projecting air up a wall, loor outlets near a wall or in the Underloor diffuser applications are being introduced into access loor facilities. These are primarily cooling and loor diffusers directed upward as a free jet can result in well-mixed, uniform temperature zones from the loor to 6 ft. high, with a stratiied region above. Underloor air distribution is being proposed as a better stratiication zone overhead. The rules for proper ventilation determine optimum conigurations. ASHRAE has sponsored several tests with loor based the various classiications of outlets are reviewed. The loor level and low level distribution classiication diagrams show Each heating diagram shows low loor level temperatures with neutral zones of varying sizes from the loor up to some T 5 Heating T 15 T 5 Cooling T 5 T 15 to delect cold air and project cold air horizontally into the room at that level. The cold air continues on to the loor height increases so does the height of the stratiication layer. Generally, 5% airlow to the window and 5% to the room is recommended. However, some adjustments to the low are beneicial, so adjustable diffusers are preferred. When a 1 to 2 ft. sofit is above the window area, the method during heating with an outlet back from the sofit cannot be used. The air spreads in the sofit and turns up at the bottom of the sofit to return to the outlet. High levels of stratiication then occur. With a sofit, vertical projection

A COOLING B HEATING T15 T5 T15 the loor level. The main result of this approach is to have outlet is directed at a horizontal or angled delection toward glass wall is that throw is modiied by approximately 1% per This method is only applicable for closed perimeter ofices. The ofice walls are necessary to turn the air down to the Side View 5 Plan View loor and back across the loor towards the exposed wall. and project down to the loor and return across the loor outlet. A high airlow and supply outlets are necessary for an airlow rate, or too high a Dt, the rolling air path can unitsspeciically gas ired ones - and high airlows are required here to prevent stratiication. The result with these systems is that heating is cycled and stratiication is It can be used in a closed ofice or open plan arrangement.

D effective draft temperatures, Ø, are then deined by: A B C D E F T 5 /L = 2 ADPI = 93 1..9 1.5.5 1.3 1.9 25 64 665662313 36 33 21 23 52.7.7.2 25 33 31 22 1234567 A F = Room Width Test Points 1 7 = Room Length Test Points.5.2 282527225 226262231 2723262824 2225232525.4.4 7355126445342 18'..4.2.4 1.8 6' 6" Height 1.3 1..4.2.2 Data at 6' 6" High Point B,6 1 1..6.6.4 1. 1. 1.8 1.3 1. T x - T c 13 3 /4' A B C D E F.4.6.8.3.9 1.6 31 63 X 5842762731 X X 39 27 23 31 33..4 32 29 23 17..2 2521242436. 2323182737.2 3128292727 2225272526..3.4.4 8.6 X.2 1.5 1.5.9.7 X X X 97649555742 X 1234567 5' Height X Downward Moving Air Upward Moving Air Horizontal Moving Air Direction.5.6.6.6.5 X.3.8 1.4 1.4.4 A B C D.2.3.9.6 1.4.4 29 33 856492736 X X X 26 26 34. Ð.4.5 33 37 25.4.3.2 271823254.2.3.2.2.4 4126283645 252121937.8.2.4.3.4 A B C D.4.4.6.6.6.9 1.9 25 34 44444127 25 36 25.8.9 32 35 25.5 4149423728 2633333241.4 2525252525 X X X.4.2.8.3.8.4.3 1.5.6 E 39.8 2 1617181938.4.4.5 E 25.9.4 252525252525.4 1.5.5 F 3.3 X.8 X.8.9 X.8 X 333333.3.4 F 37.7.7.7 X 1.5 4546 5 56544 X.4 2 1234567 1234567 2.5' Height 4" Height B B DB E

The standard speciies measurement accuracy as well as 25 cfm -19.8 Delta-T Perforated Diffuser 24 X 24 X 8" using the ASHRAE Standard 113. This igure shows lines of all points within six feet of the loor have draft temperatures exception of two points at the loor), and represented an 16 96 87 78 66 Draft Temperature 2. - 3. 1. - 2.. - 1. -1. -. -2. - -1. -3. - -2. -4. - -3. 57 38 27 6' right 5' right 4' right 3' right 2' right 1' right Center 1' left 2' left 3' left 4' left 5' left 6' left 16 6 Distance from Floor Distance From Diffuser be related to isothermal low of 5 (T ADPI 1 8 6 4 2.5 1. 1.3 2. 1.5 2. T 5 /L SYMBOL 2.5 3. 3.5 BTUH/SQ. FT. 2 4 6 8

D Total airlow rate (Q ) ( A ) ( A D D C Coeficient of entrainment Primary airlow rate from Total airlow rate at distance

O Outlet Jet Velocity V 5 5 4 3 2 15 1 8 6 5 % Short Circuiting, O 33 25 t O 2 15 1 5 5 17 13 4 3 1 Terminal Velocity 5 4 3 2 t / t 1 x 7 5 3 2 X V 5 V O V X =.8 t O t X 2 2 15 1 8 6 4 3 2 1..5 F Below or Above Ambient t x O Outlet Velocity V Diameter of Total Air, Ft. 1.4 81 49 6 24 Induction Ratio, Q / Q 28 42 5.8 8.4 11.214 4 6 8 12 16 2 5 4 3 2 15 1 8 C= 6 5 2. 1 65 8 32 4 3 16 2 8 1 6 1 6 4 2 1, cfm 8 Primary Air Q 6 X Terminal Velocity V 5 o 4 3 2 1 4 1 cfm 4 2 x 1 1 2 cfm Outlet Area.5 Ft. 21 28 42 56 84 3 4 6 8 12 2 O Q X Q O X V 5 5 = C V O V X 2 1 8 6 4 3 2 1 C= 1.4 7 56 42 28 21 14 7 Total Air Q X, 1 cfm eficiency, health and safety rather than comfort. Industrial sweat will be reduced signiicantly. Examples of warm-moist will include a study of heat stress level, physical itness of

suficient quantities and velocities to cool the worker by in a small, deined area. This can be accomplished by: Up in winter, down for summer Directing air from one work station to another Directing it away from the product or process Adjusting for worker s individual comfort pole operated and speciically designed for industrial

speciic application requirements. Delection, Zone 4 (Minimum Induction) a given throw and no delection (2.3 square feet to keep NC levels < 6. This results in the inal Delection Zone 3 (Maximum Induction) delection. be very quiet (NC 29). This results in the inal 4 Deflection Deflection 45 22 1/2 2 32 3 2 GENERAL VENTILATION: Selections should be made in the 3rd and 4th zones. SPOT COOLING: Selections should be made in the 2nd or 3rd zones. A selection in the 3rd zone will provide maximum protection. 3rd Zone 15 24 1 16 75 12 1 4th Zone 5. 6. 8. 1. 3 & 4 5 4 8 64 Throw, Ft. 5 1 & 2 2.3 ft 2 8. 1. 15. 2. 3. 4. 2nd Zone 3 25 2 15 48 4 32 24 6. 2 2 4. 5. 1 16 15 2. 3. 7.5 12 1 1. 5 8 5 5 2 A c = Ft..2.3.4.5.6.8 1.5 1 2 3 4 Throw, Ft. 2.5 4 5 Terminal Velocity 4 3 2 1.5 2.4 1 2 3 4 5 6 8 1 2 3 4 5 6 8 1 2 3 4 Flow Rate, cfm/outlet 5 1 6 1 2 3 4 1 8 6

Delection Zone 4 (Minimum Induction) (9 ft. 2 max) for a given throw and 45 delection. 6. This results in the inal selection (Pt =.4, 45 Delection Zone 3 (Maximum Induction) be for a given throw and 45 delection (55 ft. 2 3. This results in the inal selection (Pt =.39, 1, 8, 6, 1. 8. 6. 5. 4. 3. 4, 3, Throw 8. 2. 15. 1. 6. 5. 2, 4 4. delection setting. For delection setting of 22.5 add 1 NC. For delection setting of 45 increase the sound levels by 7 Delection settings: The delection settings refer to the horizontal delection shown in the product performance 2 upward vertical delection should be taken as that for a Flow Rate, cfm (in thousands) 15, 1, 8, 6, 4, 3, 2, 2 3 1 4 3 5 NC 6 7 3. 2. 1.5 1. 8 AC (ft. 2 ) 1, Velocity, 1, 1,5 2, 3, 4, 5, Pt 45 Pt

Takeoff Loss (SP U -TP N ), In. of Water.2 5.8.7.6.5.4.3.2 5 3 Arrangement I Arrangement II 4 5 6 V N =.8 V u 1. 1.5 1..8 1.5 8 1 15 2 Diffuser Neck Velocity (V N ) V U SP U AG-75 V U SP U AG 45, 65, or EG Airlow Measurements Airlow factors, obtained with the same test setup used for outlet pressures, as well as procedures for ield testing TP N & V N Arrangment I Diffuser Total Pressure TP N & V N Arrangment II B B B B together is suficient to take care of the expansion and

CHANGE OF LENGTH IN INCHES 1/4 3/16 1/8 1/16 2 4 6 8 1 12 14 16 LENGTH OF GRILLE IN FEET 18 2 When very large units are selected, suficient structural effects of lexible duct inlets. The effect of lexible ducts inlet conigurations varied for different types of diffusers. In 8 7 6 5 4 3 2 1 TEMPERATURE DIFFERENTIAL CHANGE OF LENGTH IN INCHES 2 1/2 2 1 1/2 1 1/2 2 4 6 8 1 12 14 16 18 2 LENGTH OF GRILLE IN FEET The minimum add for an ideal (gentile 9 ) lexible duct A 9 bend and lex adds.7 - in. Ps., @7 Typical 9 lex inlet will probably add 5 NC. In the middle of four diffusers with equal low rates, 8 7 6 5 4 3 2 1 TEMPERATURE DIFFERENTIAL

Keep lexible duct bends as gentle as possible. Remember - lex is a great attenuator of upstream With VAV systems, highest low only happens when lows, and work even less effectively in overhead Basis of Sound Levels Same as Sound Levels Up To 12 Manufacturer s Manufacturer s Rating db Higher With No Ratings with Equalizing Grid Equalizing Grid AIRFLOW D 8 AIRFLOW D 2 D D Sound Levels Same As Manufacturer s Ratings Sound Levels 12 to 15 db Higher Than Manufacturer s Ratings