2. Arthur Miller, CMS, RCT HVACR Training Consultant www.kam-associates.com info@kam-associates.com

3. OUTLINE 1.Air Flow Terminology 2.Classification of Duct Systems 3.Duct Design Methods 4.Fans 5.Ducts 6.Air Flow & Issues with Design of Ducts 7.Filters 8.Conclusion(s) & Solution(s)

4. A ’PRACTICAL APPROACH’ ALONG WITH SOME THEORY

9. 3 ¼ x 12 wall stack

10. Who is Liable? A.The contractor – from design to installation to service B.The filter manufacturer C.The building owner D.Nobody

11. AIR FLOW TERMINOLOGY

12. CFM Volume or Quantity of air measured in Ft 3 /min

13. FPM Velocity of the air measured in Ft/min

14. STATIC Resistance to the air flow measured in inches of water column (“w.c.)

15. Classification of Duct Systems 1.Low Pressure System - up to 2” w.c. 2.Medium Pressure System - up to 6” w.c. 3.High Pressure System - up to 10” w.c.

16. Duct Design Methods 1.Velocity Method 2.Static Regain Method 3.Equal Friction Method

17. Velocity Method 1.Select velocity for main and branch ducts. 2.Determine duct sizes. 3.Determine frictional pressure drops. 4.Select a fan.

18. Static Regain Method 1.Select velocity for main ducts. 2.Velocities are selected so the static pressure at each take-off offsets the pressure loss of the preceding section of ductwork. 3.Select a fan.

19. Equal Friction Method 1.Selection of friction loss. 2.Volume of air is known. 3.Duct is sized based on 1 and 2 above. 4.Select a fan or fan is selected.

20. FANS The ‘HEART’ of the air delivery system

21. Relationship between STATIC and CFM in respect to a FAN

22. Are they A.a direct relationship B.an indirect relationship C.neither

23. STATIC CFM

24. STATIC CFM

25. two configurations of fans

26. 1. AXIAL 2. CENTRIFUGAL

27. First, the Axial Fans

28. Definition? What makes an axial fan an axial fan?

29. ANSWER Discharge Air Flow PARALLEL to shaft of motor/fan (NO change in direction)

30. TYPES 1.tubeaxial 2.vaneaxial 3.propeller

31. TUBEAXIAL 1.operates at pressures up to 16” wc 2.wheel turns faster than propeller fan 3.efficiency up to 65%

32. VANEAXIAL 1.operates at pressures up to 20” wc 2.uses guide vanes to improve efficiency and pressure 3.most energy efficient fan

33. PROPELLER 1.operates at low speeds 2.handles large volumes of air at low pressure and at free delivery 3.efficiency is usually less than 50%

34. Performance of PROPELLOR Fans

35. PROPELLOR FAN What is the LOADING component on a PROPELLOR fan? A.CFM B.FPM C.STATIC

36. STATIC

37. This ‘LOAD’ is then imposed on the motor. How will the motor respond?

38. STATIC AMPS

39. STATIC AMPS

40. APPLICATION(S)

41. (1)The condenser on an air conditioner is very dirty. What will happen to the: fan delivery in cfm? fan motor amp. draw?

42. Fan delivery in cfm Increases Decreases Remains the same

43. Fan delivery in cfm Increases Decreases Remains the same

44. Fan motor amp. draw Increases Decreases Remains the same

45. Fan motor amp. draw Increases Decreases Remains the same

46. (2)What about a filter on an ice machine condenser? What will happen to the: fan delivery in cfm? fan motor amp. draw?

47. Fan delivery in cfm Increases Decreases Remains the same

48. Fan delivery in cfm Increases Decreases Remains the same

49. Fan motor amp. draw Increases Decreases Remains the same

50. Fan motor amp. draw Increases Decreases Remains the same

51. (3)Consider a window fan.Is ductwork connected to the fan? 1. YES 2. NO

52. (3)Consider a window fan.Is ductwork connected to the fan? 1. YES 2. NO

53. Now, the Centrifugal Fan

54. ? Definition? What makes a centrifugal fan a centrifugal fan?

55. ANSWER Discharge Air Flow PERPENDICULAR to shaft of motor/fan

56. Types of Centrifugal Wheels 1.Backward Inclined (BI) 2.Air Foil Wheels (AF) 3.Forward Curve Wheels (FC) 4.Radial Blade Wheel

57. Backward Inclined (BI)

58. 1.used with high pressure systems 2.high flow 3.high efficiency 4.noisy Backward Inclined (BI)

59. Air Foil Wheels (AF)

60. 1.used with high pressure systems 2.high flow 3.highest efficiency 4.noisy Air Foil Wheels (AF)

61. Forward Curve Wheels (FC)

62. 1.used with medium pressure systems 2.high flow 3.best for moving large volumes against low static 4.quiet Forward Curve Wheels (FC)

63. Radial Blade Wheel

64. 1.used with high pressure systems 2.medium flow 3.best for moving air against high static and contaminated airstreams Radial Blade Wheel

65. Performance of CENTRIFUGAL Fans

66. CENTRIFUGAL FAN What is the LOADING component on a CENTRIFUGAL fan? A.CFM B.FPM C.STATIC

67. CFM

68. This ‘LOAD’ is then imposed on the motor. How will the motor respond?

69. CFM AMPS

70. CFM AMPS

71. MOVIE TIME

73. APPLICATION(S)

74. How would you answer the following questions regarding CENTRIFUGAL fans?

75. (1)An addition has been added to a building and the duct system has been added onto include this addition. What will be the: A.fan delivery in cfm? B.fan motor amp. draw?

76. Fan delivery in cfm Increases Decreases Remains the same

77. Fan delivery in cfm Increases Decreases Remains the same

78. Fan motor amp. draw Increases Decreases Remains the same

79. Fan motor amp. draw Increases Decreases Remains the same

80. (2) As the air filter gets more contaminated, what will be the: A.fan delivery in cfm? B.fan motor amp. draw?

81. Fan delivery in cfm Increases Decreases Remains the same

82. Fan delivery in cfm Increases Decreases Remains the same

83. Fan motor amp. draw Increases Decreases Remains the same

84. Fan motor amp. draw Increases Decreases Remains the same

85. (3)You remove a supply air panel on a ‘hot’ day just to cool you off. What will be the: A.fan delivery in cfm? B.fan motor amp. draw?

86. Fan delivery in cfm Increases Decreases Remains the same

87. Fan delivery in cfm Increases Decreases Remains the same

88. Fan motor amp. draw Increases Decreases Remains the same

89. Fan motor amp. draw Increases Decreases Remains the same

90. ‘CENTRIFUGAL’ FAN PERFORMANCE

91. Fan Performance depends on (1)CFM (2)Outlet Velocity (3)Static Pressure (4)RPM (5)Brake Horsepower

92. Determining Fan CFMs (1)Using a Fan Curve (2)Using a Fan Chart (3)Using a Fan Law (4)Using Instruments

93. (1) Using a Fan Curve

96. Relationship between STATIC and CFM in respect to a fan

97. STATIC CFM

98. STATIC CFM

99. Relationship between STATIC and CFM in respect to the duct system

100. STATICCFM

101. STATIC CFM

105. 1 HP 3 HP 5 HP New Operating Point Original Operating Point

106. (2) Using a Fan Chart

109. PSC Motor

110. ECM Motor

111. And now, the new kid on the block. Dec Star Movie

117. Using a Fan Law 1.six fan laws 2.HVACR is affected by one of them

118. The physics of air flow dynamics dictates the following: CFM – varies as the fan speed Static – varies as the SQUARE of the speed HP – varies as the CUBE of the speed

119. APPLICATION If we increase the cfm’s by 20%, what will be required of the motor speed(rpm)? + 20%

120. If we increase the cfm’s by 20%, what will happen to the static in the system? + 40%

121. If we increase the cfm’s by 20%, what will happen to the horsepower required from the motor? + 80%

122. Using Instruments 1.Anemometer 2.Velometer 3.Manometer with Pitot Tube 4.Balometer

123. So why all the fuss about fans ?

124. Because they must deliver a volume of air that satisfies two requirements:

125. a.Equipment Efficiency b.Customer Satisfaction

126. AIR FLOW

127. So how much CFM can you ‘shovel’ into a duct?

128. That takes us to the DUCT CALCULATOR

129. ‘Rule of Thumb’ Design Static Pressures.10 (.08) for SUPPLY AIR duct.08 (.06) for RETURN AIR duct.08 (.06) for HEAT PUMP SUPPLY duct.06 (.04) for HEAT PUMP RETURN duct

131. Furnace Fan External Static Pressure.5”w.c. for the furnace fan, then subtract any external components:

132. ACCA Manual D Component Static Pressure 1.Air conditioner coil =.25”w.c. 2.Filters =.10”w.c. 3.Electric heaters =.10”w.c. to.20”w.c. 4.Humidifiers =.10”w.c. 5.Supply Outlets =.03”w.c. 6.Return Inlets =.03”w.c. 7.Dampers =.03”w.c.

133. Example #1 Furnace fan =.50”w.c. less AC coil =-.25”w.c. less air filter =-.10”w.c. less supply registers =-.03”w.c. less return grilles = -.03”w.c. less dampers = -.03”w.c. left for duct system =.06”w.c.

134. Example #2 Furnace fan =.50”w.c. less AC coil =-.00”w.c. less air filter =-.10”w.c. less supply registers =-.03”w.c. less return grilles = -.03”w.c. less dampers = -.03”w.c. left for duct system =.31”w.c.

135. Designing the Duct System  Length of duct - measured  Fittings - Equivalent Length tables  Velocity Factor - Equivalent Length tables

136. Supply and Return Plenums

137. Take-off fittings

139. Velocity Factor EL Values Fitting012345 or more 354555657080 203035404550 65758595100110

140. Velocity Factor EL Values Fitting012345 or more 354555657080 203035404550 65758595100110

141. CONCLUSION The equivalent length(EL) of the duct system has a direct relationship to the STATIC

142. FILTERS

143. Filters in relation to the SYSTEM

144. STUDY ASHRAE Published October 2012 by John Proctor, P.E. Member ASHRAE

145. California Energy Commission field research Two year old homes Most common replacement filter used is a 1 in. pleated filter

146. Air Conditioning Contractors of America’s Manual D assumes pressure drop through a filter to be approx. 0.10 in. w.c.

147. Field installations showed PD far in excess of 0.10 in. w.c.

148. Static pressures for 34 split AC/furnaces

149. Metric Filter PD Return P S Total ESP Mean: in. w.c. 0.282 - 0.417 0.887 Range: in. w.c. 0.275 – 0.792 - 0.143 – - 0.928 0.533 – 1.21 Static pressures for 34 split AC/furnaces

150. Metric Filter PD Return P S Total ESP Mean: in. w.c. 0.282 - 0.417 0.887 Range: in. w.c. 0.275 – 0.792 - 0.143 – - 0.928 0.533 – 1.21 Static pressures for 34 split AC/furnaces

151. Metric Filter PD Return P S Total ESP Mean: in. w.c. 0.282 - 0.417 0.887 Range: in. w.c. 0.275 – 0.792 - 0.143 – - 0.928 0.533 – 1.21 Static pressures for 34 split AC/furnaces

152. Metric Filter PD Return P S Total ESP Mean: in. w.c. 0.282 - 0.417 0.887 Range: in. w.c. 0.275 – 0.792 - 0.143 – - 0.928 0.533 – 1.21 Static pressures for 34 split AC/furnaces

153. Research results of PD for 53 ducted systems.

154. Filter face area required for 0.05”w.c. PD at 400 cfm/ton for one manufacturer’s line of filters 16 x 25 = 400 in 2

155. Filter face area required for 0.05”w.c. PD at 400 cfm/ton for one manufacturer’s line of filters

156. The following two charts are tests performed by Kevin O’Neill. HVAC Service Manager Carolina Clg. & Plbg. Surfside Beach, SC

161. CONCLUSION every system has air flow issues

162. CONCLUSION Unfortunately there will always be those who: 1. will not keep up with technology. 2. have always done it this way. 3. don’t need to know that. 4. will do it the least expensive way.

163. SOLUTIONS All designers of air flow systems need to check the manufacturer’s specs. of equipment before designing a system.

164. SOLUTIONS Filters may be a point of interest for poor performance of equipment and comfort.

165. SOLUTIONS The consumer is getting smarter about our industry and making demands on us.

166. SOLUTIONS Professionalism has to be promoted inside and outside the industry.

167. SOLUTIONS Continuing Education