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TABLE TABLE OF OF CONTENTSCONTENTSSECTION PAGE1 5 INTRODUCTION5 Introduction26 29January July 202120207 Pipe & fitting nomenclatureInternal Pipe vs.vs. tubeExternal heatPipe exchangerssizeDouble Pipe fitting wall coil terminology heat exchangersLiquid-to-liquid Biomass boilers heat exchangersExternal Couplings heat exchangersShell & tube heat exchangersShell Elbows& coil heat exchangers2 8 HEAT EXCHANGER TYPESFlat plate heat exchangersBrazed plate heat exchangersPlate & frame heat exchangersFan-forced liquid-to-air heat exchangersFan-coilsAir handlersGreywater heat recovery heat exchangersA Technical JournalfromCALEFFI NORTH AMERICA, INC3883 W. Milwaukee RdMilwaukee, Wisconsin 53208USATel: 414-238-2360FAX: 414-238-2366E-mail: idronics@caleffi.comWebsite: www.caleffi.usTo receive future idronics issuesFREE, register onlinewww.caleffi.us© Copyright 2019 2021Caleffi North America, Inc.Printed: Milwaukee, WisconsinUSA12 Metal pipe joining methods & materialsConductionSteel pipeConvectionStainless steel pipeWrought iron pipeBlack iron pipeTHERMAL Cast iron CHARACTERISTICS pipeOF HEAT EXCHANGERSLaminar Copper vs. water Turbulent tube flowReynolds Brass numberFlow Bronze direction through heat exchangerDetermining overall rate of heatMetallurgical joining methodstransfer (lmtd method)Overall Soft soldering rate of heat transfer –pipeBrazing heat echangerWelding3 27 HEAT TRANSFER FUNDAMENTALS4 335 51 INSTALLATION DETAILS FOR HEAT EXCHANGERS78 APPENDIX A: CALEFFI HYDRONIC COMPONENTS79 APPENDIX A: CALEFFI PLUMBING COMPONENTS79 APPENDIX B: GENERIC COMPONENTSNatural vs. forced convectionThermal radiationDetermining overall rate of heat transfer(effectiveness method)Software-based heat exchanger selectionHeat exchanger performance indicesThermal length of a heat exchangerThermal performance of water-to-air heatexchangers29 Polymer Heat exchanger pipe joining foulingmethods & materials Heat exchangers supplyingChemical Polyvinyl foulingchloride tubing (PVC)antifreeze-protected circuitsDebris ChlorinatedfoulingPolyVinyl Chloride tubing (CPVC)High-Density Polyethylene tubing (HDPE)Cross-linked Polyethylene tubing (PEX)Oxygen diffusionSnow & ice melting (SIM) systems District heatingComposite PEX-AL-PEX tubingPool HeatingHeat interface unitsDomestic Polyethylene-raised water heatingtemperature tubing Lake (PE-RT) water coolingsOn-demand PolyPropylene-random domestictubing (PP-R) Lake plate heat exchangersFusion water heatingjoining methodsSummaryHeat exchangers for non-pressurizedthermal storage tanks41 Summary6 57 HEAT EXCHANGER APPLICATIONSDisclaimer: Caleffi makes no warranty that the information presented in idronics meets the mechanical, electrical or other code requirementsapplicable within a given jurisdiction. The diagrams presented in idronics are conceptual, and do not represent complete schematics for anyspecific installation. Local codes may require differences in design, or safety devices relative to those shown in idronics. It is the responsibility44 N° 55 giugno 2019
1. INTRODUCTIONOne of humankind’s most significant achievements hasbeen the ability to generate heat and guide its movementfor useful purposes. This ability is essential to modern life,especially when it’s used to establish and maintain thermalcomfort in habitable spaces. Heat exchangers of all typesare used for this purpose.For centuries, heat was generated from fire, and methodswere developed to guide that heat into occupied areas ofbuildings. An often-cited example of early heat exchangefor improving human comfort was the Roman hypocaust.Wood-fueled fires would be maintained outside ofoccupied spaces. The hot combustion gases from thesefires were channeled through spaces under stone floorssupported on stone columns, as seen in Figure 1-1, aswell as through hollow stone walls.Today, modern heat exchangers allow heat transfer withzero mixing of the liquid or gas supplying the heat withthe liquid or gas absorbing that heat.Wood stoves are another example of centuries-old heatexchangers that allow heat from combustion gases to betransferred to occupied spaces with little, if any, release ofthose combustion gases into those spaces.Some wood and coal burning stoves also includedheat exchangers for heating domestic water. Figure 1-3illustrates the concepts used in these early systems, whichFigure 1-2Figure 1-1Figure 1-3hotwaterrangeboilercoldwaterwater jacketBecause the combustion gases were significantlywarmer than the building surfaces, heat would beabsorbed into the stone. It would then transfer throughthe stone by conduction and be released into occupiedspaces by thermal radiation and convection. This heatexchange process took place with minimal mixing of thecombustion gases and the air in occupied spaces. Assuch, the hypocaust functioned as a heat exchanger.coal / wood!burning!water heater5
Page 1 and 2: TMJOURNAL OF DESIGN INNOVATION FOR
Page 3: FROM THE GENERAL MANAGER & CEODear
Page 7 and 8: Figure 1-6 Figure 1-8Figure 1-9Figu
Page 9 and 10: Figure 2-4supplemental / auxiliary
Page 11 and 12: Figure 2-6solar thermalcollector ar
Page 13 and 14: Courtesy of Hydroflex Systems, Inc.
Page 15 and 16: Figure 2-15Figure 2-16Courtesy of B
Page 17 and 18: Courtesy of (a) Alfa Laval, and (b)
Page 19 and 20: Figure 2-24Courtesy of Alfa LavalLa
Page 21 and 22: how to account for plate thickness
Page 23 and 24: Figure 2-33Notice that the directio
Page 25 and 26: Figure 2-36Greywater heat exchanger
Page 27 and 28: 3. HEAT TRANSFER FUNDAMENTALSTwo fu
Page 29 and 30: Figure 3-3Heat output (Btu/hr/ft)60
Page 31 and 32: process. The value of (h) varies wi
Page 33 and 34: 4. THERMAL CHARACTERISTICS OF HEAT
Page 35 and 36: ( )q sAF T 4 4− T12 1 2⎡ 1 q =+
Page 37 and 38: 0.00032 ft ⋅sec( ) 1− ( ∆T )
Page 39 and 40: Figure 4-9enters the secondary side
Page 41 and 42: Figure 4-11FINNED-TUBE BASEBOARDout
Page 43 and 44: CC ratio= C ratio min= C minC maxC
Page 45 and 46: Figure 4-13cthe minimum surface are
Page 47 and 48: absorbing heat. The latter is a muc
Page 49 and 50: which to release its heat. However,
Page 51 and 52: 5. INSTALLATION DETAILS FOR HEAT EX
Page 53 and 54: Figure 5-4aFigure 5-5isolation /pur
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Figure 5-8temperature sensorsetpoin
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6. HEAT EXCHANGER APPLICATIONSThis
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Figure 6-3a Figure 6-3bCourtesy of
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Figure 6-5to/fromspace heatingloadb
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Courtesy of Diversified Heat Transf
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Figure 6-10isolation / flush valves
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Courtesy of Diversified Heat Transf
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Figure 6-14modulating /condensingbo
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Figure 6-15multiple boilerstaging &
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Figure 6-17an existing boiler that
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Figure 6-19pipingbelowfrost lineret
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Figure 6-22air handlersbalancingzon
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APPENDIX B: CALEFFI PLUMBING COMPON
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