ACB35 Concealed Ceiling-Mounted With Vertical and Integral Drain Pan (Vertical down discharge) Technical Data Concealed Ceiling Mounted Model With Vertical and Integral Drain Pan Active Chilled Beams
APPLICATION CONSIDERATIONS The general design intent of an Active Chilled Beam system is for the central system to circulate only the amount of primary air needed for ventilation and latent load purposes, with the Active Chilled Beams providing the additional sensible cooling (and heating) and air movement required through the induced room air and secondary water coil. Active Chilled Beam systems transfer a large portion of the cooling (and heating loads) from the less efficient air distribution system (fans and ductwork) to the more efficient water distribution system (pumps and pipes). The net result of this shift in loads is lower energy consumption and operating costs. Primary Air System There are a number of important issues affected by the primary airflow rates, pressure and temperature chosen in the primary air system design as follows: Ventilation Air Requirements Primary Air Latent Cooling Capacities Risk of Over-cooling/Reheating Building Pressurization Control Choosing the primary air flow rates and temperature requires considerable thought and judgment. Decreasing the primary air temperatures offers the opportunity to decrease fan energy consumption (within the limits of the ventilation air requirement) and increasing latent cooling capacities, while potentially increasing the risks of over-cooling/reheating. Other design concerns with the primary air system design include: Air Handler/Ductwork Zoning and Resetting of Primary Air Temperatures Air Distribution Considerations Noise Level Requirements Heating Secondary Water System The chilled water temperature entering the Active Chilled Beam secondary water coils must be at or above the room design dew point temperature to avoid formation of condensate on the coil. Using the room design temperature of 24 ºC db/ 17ºC wb (50% relative humidity), the room air dew point temperature is 12.8 ºC. In this case the minimum entering chilled water temperature to the Active Chilled Beams should be 12.8 ºC or higher (typically around 14-16 ºC is used in Practice). Choosing the secondary chilled water temperature is another area requiring considerable thought and judgment. A higher chilled water temperature will add to the margin of safety relative to condensation concerns and increase the hours when a water-side economizer can be used to serve the active chilled beams, but could have the effect of increasing the fan and pump energy requirements and unit costs. Heating The suitability of the use of overhead heating from the ceiling in any system (Active Chilled Beam, VAV, etc) is dependent on the extent of heat losses along the perimeter. In general overhead heating is acceptable if the heat losses are less than 384 W/linear meter along the perimeter. The air distribution discharge arrangements employed vary based on the extent of heat losses along the perimeter. 2
UNIT SELECTION There are two methods for selecting DADANCO Active Chilled Beams a manual method using the enclosed tables and an optimized design method using the DADANCO Specifier computerized product selection program. The following will demonstrate the manual selection method using the data from the Quick Selection Capacity and Sound Level tables. For optimized unit selections using the DADANCO Specifier computerized product selection program or for special selection assistance, contact Dadanco LLC via phone (413) 564 5657, fax (413) 568 5384 or e-mail at info@dadanco.com. MANUAL SELECTION METHOD The unit performance data in the Quick Selection Capacity tables in this publication is given for the ACB35 (vertical down discharge) concealed ceiling-mounted model in both 2-pipe and 4-pipe coil configurations. The capacity ratings are based on a typical nozzle selections. With the optimized design method using the DADANCO Specifier computerized selection program, both the size/number of nozzles will vary and will be optimized to provide the exact performance required. Ventilation Air To begin your unit selections determine the minimum ventilation air required for each zone (using as a minimum that prescribed by ASHRAE 62). This would be the minimum amount of primary air that could delivered to the Active Chilled Beams in each zone. Latent Cooling Prior to selecting the Active Chilled Beams the primary air quantity and temperature must be determined to provide for adequate ventilation air, as well as for the latent cooling capacity required. It is very important that both of these requirements are determined and satisfied by the primary air in every zone before selecting the Active Chilled Beams. Using the ventilation air quantity as the primary air quantity, determine the latent cooling being provided by the primary air based on the airflow, room design and primary air temperatures chosen. Compare the latent cooling capacity being provided by the primary air to the latent load in each zone. Often times the primary air quantity and temperature will be driven by the latent cooling loads and more (or preferably colder/drier) primary air will be required than that needed solely for ventilation air purposes to satisfy the zone latent loads. Remember that the latent loads in an Active Chilled Beam system must be fully satisfied by the primary air as insufficient latent cooling capacities can lead to condensation issues. Active Chilled Beam Unit Type The type of unit (s) to be selected must be chosen. This publication includes data for the concealed ceiling-mounted models. Quick Selection Cooling and Heating Capacity Tables Model ACB35 ACB35 Conceleld Ceiling -Mounted Models Air Discharge Configuration Vertical Down 2-Pipe Vertical Down 4-Pipe The performance data in the Quick Selection Capacity tables are based on assumed operating conditions of: 125 Pa inlet static pressure 24 C db/17 C wb room design temperature (50% relative humidity, 0.00925 kg Water/kg Dry Air humidity ratio) 12.0 C db/11.3 C wb primary air temperature (90% relative humidity, 0.00800 kg Water/kg Dry Air humidity ratio) 14.0 C entering chilled water temperature for cooling 50.0 C entering hot water temperature for heating 0.10 L/s water flow rate Sea level elevation The correction factor tables can be used to adjust the cooling and heating capacities shown in the Quick Selection Capacity tables for operating conditions that differ from the above assumptions. 3
Sensible Cooling The Quick Selection Cooling Capacity tables show the sensible and latent cooling capacity being provided by the primary air, the sensible cooling capacity being provided by the secondary water coil and the total unit sensible cooling capacity. Assume we want to select an ACB35 2-pipe unit and that the total sensible cooling capacity required was 1,350 W with a minimum primary airflow of 28 L/s. Using the correct Quick Selection Cooling Capacity table on page 7, a total sensible cooling capacity of 1,369 W (412 W from the primary air and 957 W from the secondary water coil) could be provided by a 1500 mm unit using 28 L/s of primary air. Remember this amount of primary air must be sufficient to provide the necessary ventilation air and latent cooling capacities required. The performance data in the Quick Selection Cooling Capacity tables is based on TRA TPA of 12 C (24 ºC 12 ºC). Use the correction factor for primary air temperature less room design temperature differences other than the 12 C T temperature difference used in the Quick Selection Cooling Capacity tables. Primary Air Temperature Correction Factor Cooling Primary Air Temperature Correction Factor Temperature Room Air Primary Air Applied to Primary Air TPA TRA TPA Sensible Cooling Capacity (º C) (º C) KPA 10 14 1.17 11 13 1.08 12 12 1.00 13 11 0.92 14 10 0.83 15 9 0.75 16 8 0.67 17 7 0.58 18 6 0.50 19 5 0.42 Using the above base unit selection, the sensible cooling being provided by the primary air is 412 W. If the primary air temperature was 11 C (rather than the 12 º C assumed in the tables), the actual temperature difference is 13 C (rather than the 12 C used in the tables). The corrected sensible cooling capacity of the primary air at the 13 C T is 445 W ( 412 W x 1.08). The performance data in the Quick Selection Cooling Capacity tables is based on a TRA TCHW of 10 C T (24 ºC 14 ºC). Use the correction factor for room design temperature less chilled water temperatures other than the 10 C T temperature difference used in the Quick Selection Cooling Capacity tables. Water Temperature Correction Factor Cooling Chilled Water Temperature Correction Factor Temperature Room Air Chilled Water Applied to Secondary TCHW TRA TCHW Sensible Cooling Capacity CHW RA CHW (º C) (º C) KCHW 13.5 10.5 1.05 14 10 1.00 14.5 9.5 0.95 15 9 0.90 15.5 8.5 0.85 Using the above base unit selection, the sensible cooling capacity being provided by the secondary water coil is 957 W. If the chilled water temperature was 15 C (rather than the 14 ºC assumed in the tables), the actual temperature difference is 9 C (rather than the 10 C used in the tables). The corrected sensible cooling capacity of the secondary water coil at the 9 C T is 861 W (957 W x 0.90). Remember that the chilled water temperature must be above the room dew point temperature to avoid condensation issues. Throw and Sound Levels Consult the Throw and Sound Level tables to ensure proper air distribution and noise levels within each zone. Use conventional air distribution application guidelines when considering placement of the Active Chilled Beams. Throw performance will be determined depending on the supply air outlet diffuser chosen for use with the ACB35. 4
Heating The Quick Selection Heating Capacity tables show the sensible heating being provided by the primary air, the sensible heating being provided by the secondary water coil and the total unit sensible heating capacity. Remember that if the primary in the heating mode is being delivered at a temperature below the room design temperature, the heating required to bring the primary air up to the room design temperature must be added to the heating load that must be satisfied by the Active Chilled Beam s secondary water coil. Using the same base unit selection and the correct Quick Selection Capacity table on page 8, the unit would provide a total sensible heating capacity of 2,242 W (-343 W from the primary air and 2,571 W from the secondary water coil) using 28 L/s of primary air (based on the operating condition assumptions used in the Quick Selection Heating Capacity tables). The performance data in the Quick Selection Heating Capacity tables are based on a room design temperature less primary air temperature of 10 C T temperature difference (22 ºC 12 ºC). For primary air temperatures other than the 12 ºC adjust the amount of heating being provided by the primary air using the formula of: QPA = 1.226 x PA x (TPA TRA) Using the above base unit selection, the sensible heating being provided by the primary air is 343 W. If the primary air temperature was 18 C (rather than the 12 º C assumed in the tables), the corrected sensible heating capacity of the primary air is 137 W. The heating provided by the active chilled beam would increase to 2,434 W (-137 W from the primary air and 2,571 W from the secondary water coil). The performance data in the Quick Selection Heating Capacity tables is based on a THW TRA of 28 C (50 ºC 22 ºC). Use the correction factor for hot water temperature less room design temperature other than the 28 C T temperature difference used in the Quick Selection Heating Capacity tables. Water Temperature Correction Factor Heating Hot Water Temperature Correction Factor Temperature Hot Water Room Air Applied to Secondary THW THW TRA Heating Capacity (º C) (º C) KHW 30 8 0.29 35 13 0.46 40 18 0.64 45 23 0.82 50 28 1.00 55 33 1.18 60 38 1.36 Using the above base unit selection, the sensible heating being provided by the secondary water coil is 2,571 W. If the hot water temperature was 40 C (rather than the 50 ºC assumed in the tables), the actual temperature difference is 18 C (rather than the 28 C used in the tables). The corrected sensible heating capacity of the secondary water coil at the 18 C T is 1,645 W (2,571 W x 0.64) and the active chilled beam heating capacity would decrease to 1,302 W (-343 W from the primary air and 1,645 W from the secondary water coil). WATER FLOW RATES The cooling and heating capacities shown in the Quick Selection Capacity tables are based on water flows rates of 0.10 L/s. Use the water flow correction factor for water flow rates other than 0.10 L/s. Water Flow Capacity Correction Factor Cooling & Heating Water Flow (L/s) 0.15 0.14 0.13 0.12 0.11 0.10 0.09 0.08 0.07 0.06 0.05 0.04 0.03 600 mm Length 1.02 1.02 1.01 1.01 1.01 1.00 0.99 0.98 0.96 0.96 0.94 0.90 0.85 900 mm Length 1.02 1.02 1.02 1.01 1.01 1.00 0.99 0.98 0.96 0.95 0.93 0.89 0.82 1200 mm Length 1.03 1.03 1.02 1.02 1.01 1.00 0.99 0.98 0.96 0.93 0.90 0.85 0.77 1500 mm Length 1.04 1.03 1.03 1.02 1.01 1.00 0.99 0.97 0.95 0.92 0.88 0.82 0.72 1800 mm Length 1.05 1.04 1.03 1.02 1.01 1.00.098 0.96 0.94 0.90 0.85 0.78 0.67 5
Elevation The performance data in the Quick Selection Capacity tables is based air densities at sea level. Use the correction factor for elevations other than sea level. Using the previous example, the total sensible cooling being provided by the active chilled beam at sea level is 1,369 W. If the installation was at 1,200 meters above sea level, the total unit sensible cooling capacity is 1,177 W (1,369 W x 0.86). COMPUTERIZED SELECTION METHOD Elevation Correction Factor Cooling & Heating Elevation Above Correction Factor Sea Level Applied to Capacities (Meters) KE 300 0.96 600 0.93 900 0.90 1200 0.86 1500 0.83 1800 0.80 The Dadanco s Specifier computerized selection program can be accessed on our website (www.dadanco.com). To request a selection, please contact your local sales representative (see our website for a listing of representatives). A list of the typical inputs needed for a unit selection is as follows: 6
ACB35-2-Pipe Quick Selection Cooling Capacity Primary Air Cooling Sensible Cooling (W) Primary Airflow Sensible Latent (L/s) (W) (W) Nominal 600 mm Nominal 900 mm Nominal 1200 mm Nominal 1500 Nominal 1800 mm mm 7 103 31 298 401 9 137 42 347 484 422 559 12 172 52 386 558 475 646 528 700 14 206 62 392 598 530 736 581 787 17 240 73 593 833 633 874 713 953 19 275 83 616 891 691 966 763 1037 839 1114 21 309 94 629 939 754 1063 813 1122 892 1201 24 343 104 626 969 766 1110 867 1211 940 1283 26 378 115 782 1159 924 1301 983 1361 28 412 125 784 1196 957 1369 1036 1448 31 447 135 984 1431 1092 1539 33 481 146 1001 1482 1151 1632 35 515 156 1008 1523 1169 1684 38 550 167 1006 1555 1195 1745 40 584 177 1212 1796 42 618 187 1222 1840 45 653 198 1224 1877 47 687 208 1220 1907 Operating Conditions Room Design Dry Bulb Temperature 24.0 ºC Room Design Wet Bulb Temperature 17.0 ºC Room Design Relative Humidity 50.0 % Room Design Dew Point Temperature 12.90 ºC Room Design Humidity Ratio 0.00925 kg Chilled Water Supply Temperature 14.0 ºC Chilled Water Flow Rate 0.10 L/s Primary Air Dry Bulb Supply Temperature 12.0 ºC Primary Air Wet Bulb Temperature 11.1 ºC Primary Air Relative Humidity 90.0 % Primary Air Humidity Ratio 0.00800 kg Primary Air Static Pressure 125 Pa 7 kgwater Water/kg Dry Air kg Water/kg /kgdry Air
Primary Air Heating ACB35-2-Pipe Quick Selection Heating Capacity Sensible Heating (W) Primary Nominal 600 mm Nominal 900 mm Nominal 1200 Nominal 1500 Nominal 1800 Airflow Sensible mm mm mm (L/s) (W) 7-86 800 718 9-114 932 822 1134 1024 12-143 1039 901 1276 1138 1420 1282 14-172 1054 889 1425 1260 1562 1397 17-200 1593 1401 1702 1510 1916 1723 19-229 1656 1437 1857 1637 2050 1830 2255 2035 21-258 1692 1444 2026 1779 2186 1939 2397 2149 24-286 1683 1408 2060 1785 2332 2057 2526 2251 26-315 2101 1799 2483 2180 2642 2340 28-343 2106 1777 2571 2242 2785 2456 31-372 2646 2289 2936 2579 33-401 2692 2307 3093 2709 35-429 2710 2298 3142 2730 38-458 2704 2264 3212 2773 40-487 3259 2792 42-515 3285 2790 45-544 3290 2768 47-572 3278 2729 Operating Conditions Room Design Dry Bulb Temperature 22.0 ºC Room Design Wet Bulb Temperature Room Design Relative Humidity Room Design Dew Point Temperature Room Design Humidity Ratio Hot Water Supply Temperature 50.0 ºC Hot Water Flow Rate 0.10 L/s Primary Air Dry Bulb Supply Temperature 12.0 ºC Primary Air Wet Bulb Temperature Primary Air Relative Humidity Primary Air Humidity Ratio Primary Air Static Pressure 125 Pa 8
ACB35-4-Pipe Quick Selection Cooling Capacity Primary Air Cooling Sensible Cooling (W) Primary Airflow Sensible Latent (L/s) (W) (W) Nominal 600 mm Nominal 900 mm Nominal 1200 mm Nominal 1500 Nominal 1800 mm mm 7 103 31 274 377 9 137 42 316 454 380 518 12 172 52 349 521 424 596 469 641 14 206 62 354 560 469 675 512 718 17 240 73 520 760 553 794 618 858 19 275 83 538 813 599 874 657 932 718 993 21 309 94 549 858 648 957 697 1006 759 1068 24 343 104 546 890 658 1001 739 1082 797 1140 26 378 115 670 1048 782 1160 830 1208 28 412 125 671 1084 808 1220 871 1283 31 447 135 829 1276 915 1361 33 481 146 842 1323 960 1441 35 515 156 848 1363 974 1490 38 550 167 846 1395 995 1544 40 584 177 1008 1592 42 618 187 1016 1634 45 653 198 1017 1670 47 687 208 1014 1701 Operating Conditions Room Design Dry Bulb Temperature 24.0 ºC Room Design Wet Bulb Temperature 17.0 ºC Room Design Relative Humidity 50.0 % Room Design Dew Point Temperature 12.90 ºC Room Design Humidity Ratio 0.00925 kg Chilled Water Supply Temperature 14.0 ºC Chilled Water Flow Rate 0.10 L/s Primary Air Dry Bulb Supply Temperature 12.0 ºC Primary Air Wet Bulb Temperature 11.1 ºC Primary Air Relative Humidity 90.0 % Primary Air Humidity Ratio 0.00800 kg Primary Air Static Pressure 125 Pa 9 kgwater Water/kg Dry Air kg Water/kg /kgdry Air
Primary Air Heating ACB35-4-Pipe Quick Selection Heating Capacity Sensible Heating (W) Primary Nominal 600 mm Nominal 900 mm Airflow Sensible (L/s) (W) 7-86 667 581 Nominal 1200 mm Nominal 1500 mm Nominal 1800 mm 9-114 777 663 945 830 12-143 865 722 1063 920 1183 1040 14-172 878 707 1187 1015 1301 1130 17-200 1328 1127 1419 1218 1596 1396 19-229 1380 1151 1547 1318 1708 1479 1879 1650 21-258 1410 1152 1688 1431 1822 1564 1997 1740 24-286 1402 1116 1717 1430 1943 1657 2105 1819 26-315 1751 1436 2069 1754 2202 1887 28-343 1755 1412 2143 1799 2321 1978 31-372 2205 1833 2447 2074 33-401 2243 1842 2578 2177 35-429 2258 1829 2619 2189 38-458 2253 1795 2677 2219 40-487 2716 2229 42-515 2737 2222 45-544 2742 2198 47-572 2732 2160 Operating Conditions Room Design Dry Bulb Temperature 22.0 ºC Room Design Wet Bulb Temperature Room Design Relative Humidity Room Design Dew Point Temperature Room Design Humidity Ratio Hot Water Supply Temperature 50.0 ºC Hot Water Flow Rate 0.10 L/s Primary Air Dry Bulb Supply Temperature 12.0 ºC Primary Air Wet Bulb Temperature Primary Air Relative Humidity Primary Air Humidity Ratio Primary Air Static Pressure 125 Pa 10
ACB35-1200 mm Unit Sound Data Primary Airflow 100Pa Inlet Static Pressure 150 Pa Inlet Static Pressure 200 Pa Inlet Static Pressure (CFM) NC db (A) NC db (A) NC db (A) High Nozzle Pitch 30-14 35-19 40 16 24 Medium Nozzle Pitch 40-16 50 15 22 60 20 26 Low Nozzle Pitch 55 16 23 70 22 27 80 26 31 Note: Room Attenuation effect of 10 db has been applied when calculating NC levels. Note: While every effort is made to ensure the details contained in this publication are current and up-to-date, in the interest of ongoing product development DADANCO reserves the right to alter the same without notice. 11
260 North Elm Street Westfield, MA 01085 Ph: (413) 564 5657 Fax: (413) 568 5384 www.dadanco.com info@dadanco.com DADANCO MESTEK Joint Venture LLC (DADANCO) is jointly owned by subsidiaries of Dadanco Pty Ltd headquartered in Adelaide, Australia and Mestek, Inc. headquartered in Westfield, MA. Mestek is a diversified manufacturer of HVAC products with sales of over $400m. Mestek s HVAC companies include Smith Cast Iron Boilers, Hydrotherm, RBI Boilers & Water Heaters, Sterling, Vulcan, Airtherm, Applied Air, Anemostat, Air Balance, Arrow United, L. J. Wing, Lockformer and many others. 12 May 2010