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Basic Heat Transfer Concepts

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Basic heat transfer concepts and terminology for use in steam and hot water systems. Topics include:
Heat Flow
Thermal Conductivity
Heat Transfer
Heating Coils
Surface Area
Materials

Published in: Engineering
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Basic Heat Transfer Concepts

  1. 1. ©2006 Armstrong International, Inc. ® Basic Heat Transfer ConceptsBasic Heat Transfer Concepts
  2. 2. 2““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® Basic Heat Transfer ConceptsBasic Heat Transfer Concepts And Their Relationships to Heating Coil Selection TTAirAir TTSteamSteam TTsteamsteam >>> T>>> TAirAir
  3. 3. 3““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® Heat TransferHeat Transfer • Only occurs when there is a temperature difference • Flows faster when this difference is higher • Always flows from high to low temperature • Is greater with greater surface area • Some materials transfer heat better than others
  4. 4. 4““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® Heat Flows from High to LowHeat Flows from High to Low TTAirAir TTSteamSteam TTsteamsteam >>> T>>> TAirAir
  5. 5. 5““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® Thermal Conductivity of Common CoilThermal Conductivity of Common Coil MaterialsMaterials Material Thermal Conductivity Copper 2724 Aluminum 1536 Steel 314 Cupro-Nickle 90/10 310 Cupro-Nickle 70/30 200 Stainless Steel 108
  6. 6. 6““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® To Get More Heat Transfer From BareTo Get More Heat Transfer From Bare Tubes . . .Tubes . . . Add Fins to Increase Surface Area
  7. 7. 7““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® Relative Heat Transfer:Relative Heat Transfer: Identical Coils w/Different Tube MaterialsIdentical Coils w/Different Tube Materials Tube Material Relative HT Capacity Copper 1.00 Aluminum 1.00 Steel 0.98 Stainless Steel 0.95
  8. 8. 8““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® Relative Heat Transfer:Relative Heat Transfer: Identical Coils w/Material Combinations*Identical Coils w/Material Combinations* Tube Material Fin Material Relative HT Capacity Steel Copper Keyfin 1.05 Steel Aluminum Keyfin 1.00 Stainless Steel Aluminum Keyfin 0.94 Steel Steel L Fin 0.92 Stainless Steel Stainless Steel L Fin 0.58 *At 800 FPM, 7FPI & 55 psig
  9. 9. 9““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® Heat Transfer EquationHeat Transfer Equation Q = U x A x LMTD where Q = Heat Transfer Rate (BTU/hr) U = Heat Transfer Coefficient (BTU/hr/ft2 /°F) A = Surface Area (ft2 ) LMTD = Log Mean Temperature Difference (b/w the Steam and the Air)
  10. 10. 10““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® ©2002 Armstrong International, Inc. Assembly ConceptsAssembly Concepts
  11. 11. 11““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® Bare Tube CoilsBare Tube Coils Heat Exchange = U x Surface Area x ∆T Surface Area 1'' Pipe = 1 Sq Ft / Linear Ft
  12. 12. 12““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® Extended Surface CoilsExtended Surface Coils Fin Area >>>>> Tube Area Tube is Irrelevant in Heat Transfer Fin Element Plate Fin Wound Fin
  13. 13. 13““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® Coil ConstructionCoil Construction 1, 2, and 3 Row Coils Cond. Conn. Cond. Header Finned Tube Steam Header Steam Conn. 6 Tubes in the Face4 Tubes in the Face 7 FPI 1 Inch 4 FPI
  14. 14. 14““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® Casings and Air BafflesCasings and Air Baffles Coil Casings Air Baffles Flanges Casing Depth Side Baffle Header Baffle Mounting Holes
  15. 15. 15““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® Coil Casing TypesCoil Casing Types Turned-Out Flange Standard Flange for Duct-Mounted Coils Turned-In Flange Used w/ Removable Coils or Where mounting holes are not needed & smooth casing face is wanted Dimensions & Spacing 7/16" 1-1/2” 3/4”
  16. 16. 16““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® Removable (Drawer) CoilsRemovable (Drawer) Coils • Core installed in a casing w/ flanges on 3 sides and a mounting place on the 4th side • Coil slides into outer casing like a drawer Bolt Holes Lifting Lug Mounting Plate
  17. 17. 17““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® Coil ConfigurationCoil Configuration Air Inlet Air Outlet Steam Horizontal Air Flow Horizontal Tubes Vertical Tubes Condensate
  18. 18. 18““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® Coil ConfigurationCoil Configuration Vertical Up Air Flow Horizontal Tubes Vertical Down Air Flow Horizontal Tubes Air Inlet Side Air Outlet Side Air Outlet Side Air Inlet Side
  19. 19. 19““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® Parallel Multiple CoilsParallel Multiple Coils
  20. 20. 20““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® Series Multiple CoilsSeries Multiple Coils Steam Supply End Air Flow Condensate Return End
  21. 21. 21““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® 4 Coils in Parallel x 3 Coils in Series • 12 Coils Total • Drain each coil separately • 12 Traps may discharge to common Header Multiple Coil InstallationMultiple Coil Installation • Common steam supply OK
  22. 22. 22““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® Heavy Duty ConstructionHeavy Duty Construction Min. 0.016” Thick Fins on 12 Ga. CS 0.109” Thick Tubes 12 Ga. Casing and Baffles Sch 80 Connections Sch 40 Headers 250 psig Standard Pressure Rating
  23. 23. 23““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® Heavy Duty ConstructionHeavy Duty Construction • Header, Connections & Tubes (wetted parts) Same Material • No Galvanic Corrosion • All Joints Welded • No Leaks • Thicker Materials • Fights Corrosion
  24. 24. Model Number SelectionModel Number Selection
  25. 25. Extended Surface (Fin Tube) HeatingExtended Surface (Fin Tube) Heating CoilsCoils
  26. 26. 26““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® Which Fin Type?Which Fin Type? Standard KeyFin • Tight joint over wide temperature range • Best for dissimilar tube and fin materials
  27. 27. 27““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® Which Fin Type?Which Fin Type? L-Fin • L-shaped foot tension wound over knurled tube • Best for same material tubes & fins • Large contact area for high heat transfer • Some corrosion protection for tube
  28. 28. 28““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® Tube MaterialsTube Materials Carbon Steel Affords both strength & corrosion resistance Standard 12 Ga A-214 ERW (1” or 1½” OD) Optional 10 Ga A-214 ERW 10 Ga or 12 Ga A-179 Seamless Stainless Steel (304L or 316L) When corrosive steam is present or when ideal piping & trapping practices cannot be followed 14 Ga (1” OD) & 12 Ga (1½” OD)
  29. 29. 29““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® Fin MaterialsFin Materials Steel Fins stand up against aggressive cleaning 0.024” Thick on 1” OD or 1 1/2” OD Tubes 0.036” Thick on 1 ½” OD Tubes Aluminum Fins provide the best overall value 0.020” Thick Keyfin on all Tube Sizes 0.030” Thick Keyfin on all Tube Sizes Stainless Steel Fins fight high external corrosion 0.020” Thick Type 304L & 316L on 1” OD Tubes Copper Fins provide the best heat transfer 0.016” Thick on All Tube Sizes
  30. 30. 30““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® Conns/Headers/CasingConns/Headers/Casing Headers Same Material As Tubes With Welded Construction Connections Steel: Sch 80 (screwed) or Sch 40 (flanged) Stainless Steel: Sch 40 (screwed) or Sch 10 (flanged) Casing 12 Ga. Galvanized Steel or 12 Ga Stainless Steel
  31. 31. 31““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® Coil TypeCoil Type • Standard (Type S) • Centifeed (Type C) • Tendam (Type T) • Centifeed Tandem (Type P)
  32. 32. Type S coils are available with opposite-end connections only Type C coils are available with same-end connections only AIR FLOW
  33. 33. 2-Row Standard Coil 2-Row Centifeed Coil AIR FLOW
  34. 34. Type T coils have opposite-end connections Type P coils have same-end connections AIR FLOW
  35. 35. 35““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ® Armstrong PromiseArmstrong Promise We provide intelligent system solutions that improve utility performance, lower energy consumption, and reduce environmental emissions . . . while providing an “enjoyable experience”! 35““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ®
  36. 36. ®® ““Expect manyExpect many enjoyable experiencesenjoyable experiences!”!” David M. ArmstrongDavid M. Armstrong ®

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