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Flow of water in pipesIt would be inappropriate to discuss this wide subject in any depth here: a considerableliterature in terms of text books and technical papers is available and an adequatebibliography is presented in the Guide Section C4. For present purposes it is enough tonote that the relationship between mass flow rate and loss of pressure is complex anddepends upon the velocity of flow;the diameter of the pipe;the roughness of the internalwetted surfaces and certain temperature-dependent characteristics of the fluid flowingsuch as specific mass and viscosity. The Guide Section C4 provides a selection of tablesshowing pressure loss and mass flow of water at several temperatures and for a range ofsteel and copper pipes.The mass flow of water required to convey a given quantity of heat from a central heatsource to the various heat emitters, in unit time, is a function of the temperature difference(t) between the flow (t f ) and the return (t r ) and of the specific heat capacity of water.This latter may, for practical purposes over the range of temperatures considered here, betaken as constant as 4:2 kJ/kg K. Mass flow may thus be calculated from:kg/s ˆ (kJ/s)/(4:2t)Water systems - principles 233In a complex system where heat loads are known only in energy (kW) terms, this is atedious calculation to work out a great many times for each and every pipework section,as required by the tables included in the Guide Section C4, and one which may lead tonostalgic recollections of the Imperial system where units of heat flow had a calorimetricbase. However, since 1 kW ˆ 1 kJ/s, it is easy to produce data in more direct terms (kW/K) by simple substitution in the expression set out above. By adoption of this approach, itis possible to retain the kilowatt as the base unit throughout all calculations: heat loss;selection of heat emitting equipment;piping design and, finally, the overall totals forboiler power. It must be remembered always that the kilowatt is no more than a measureof energy flow and use of it in this manner is an aid towards understanding the thread ofcontinuity which persists from first to last.Figure 9.1 has been prepared on this basis to give a vertical scale of energy flow in kW/Kagainst a base scale of pressure loss in Pa/m run, for water flow at 75 C in steel pipes.Similar data could be provided for medium and high temperature hot water systems but thetemperature ranges at which these operate are less well established: since they are not, use ismade of correction factors and the Guide Section C4 includes a table listing those appropriateto a water temperature of 150 C. Since the error involved in using Figure 9.1 withoutcorrection is only about 3%, it would be out of place to pursue this added complexity here.Where small bore copper tube is to be used for low temperature systems, however, it isnecessary to use alternative data since both the roughness of the wetted surfaces and theinternal pipe diameters vary from those of steel. Reference to Figure 9.2 provides thealternative information, again presented on the basis of energy flow. For water flow inPVC pipework, refer to basic data in Chapter 21 and to manufacturers' literature.Flow of water through single resistancesIn parallel with the loss of pressure consequent on flow through straight pipes, additionallosses arise at bends, branches, valves, etc., and at major components such as boilers, heatemitters and so on. These come about as a result of disruption to the velocity profilewhich is developed in flow along straight pipes, the turbulence created at the single
234 Piping design for indirect heating systems20010086Velocities in m/s0.51.09.67.72.0150 1259.9 8.06.14.410080Water flow in energy units kW/K543210865435.324.11.08 2.9654 2.00.10.27.05.54.02.82.21.58.56.75.03.52.82.01.41.15.84.13.32.31.71.40.90.73.6 65501.9401.5 321.1 250.8 200.5 150.4 10Pipe sizes in mm31.521.00.11.00.80.70.50.40.3860.50.35430.40.220.2Units at pointsthus areequivalent lengthsin metres for ζ = 10.010.12 3 4 5 6 8 2 3 4 5 6 8 2 3 4 5 6 8 2 3 4 5 6 81.0101001000Pressure loss in Pa per metre run (Pa/m)Figure 9.1 Sizing chart in energy units (kW/K) for water flow at 75 C in steel pipes (BS 1387: medium)resistance persisting for a considerable distance downstream. The pressure loss characteristicsof most types of single resistance have been determined experimentally, as a functionof flow velocity, and are represented by the symbol .
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Faber and Kell's Heating andAir-con
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Faber and Kell's Heating andAir-con
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viiiContentsOther systems 396Altern
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xiiPreface to the ninth editionadvi
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2 FundamentalsBefore any part of th
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4 FundamentalsSpecific heat capacit
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6 Fundamentalsas insulators have a
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8 FundamentalsTable 1.4 Examples of
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10 FundamentalsIt has been suggeste
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12 FundamentalsTable 1.7 Wind-chill
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14 Fundamentalsthermometer, used fo
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16 Fundamentalsmeasure them, applic
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18 FundamentalsInletventilationTher
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20 The building in wintercoincide a
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22 The building in winter20GlassTem
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24 The building in winterFor the in
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26 The building in winterTable 2.2
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28 The building in winter4.0Plan8.5
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30 The building in wintermost commo
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32 The building in winterExposed el
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34 The building in winterFigure 2.4
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38 The building in winterInsulation
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40 The building in winterSurfaceAre
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42 The building in winterFrom Table
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44 The building in winterTemperatur
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46 The building in winterThe import
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50 The building in winterIntermedia
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52 The building in winterInside tem
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54 The building in winterDesigntemp
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56 The building in winterFrom earli
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60 The building in winterTemperatur
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62 The building in winterfollowing
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64 The building in winterIt has bee
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Chapter 3The building in summerThe
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68 The building in summerfrom simpl
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18070 The building in summerinforma
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72 The building in summerIncidence
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74 The building in summertime of pe
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76 The building in summerTable 3.2
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84 The building in summerFigure 3.9
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86 The building in summerAB B C a1
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88 The building in summerConduction
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92 The building in summerLossesMoto
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94 The building in summer(a)(b)Figu
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Chapter 4Survey of heating methodsH
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98 Survey of heating methodsTable 4
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100 Survey of heating methodsIndust
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102 Survey of heating methodsRadian
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104 Survey of heating methodsHeatex
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106 Survey of heating methodsReturn
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108 Survey of heating methodsReflec
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110 Survey of heating methodsCerami
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112 Survey of heating methodsTubula
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114 Survey of heating methodsthey a
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116 Survey of heating methodsFactor
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118 Survey of heating methodsrelian
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Chapter 5Electrical storage heating
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122 Electrical storage heatingTable
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124 Electrical storage heatingR 3
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126 Electrical storage heatingAs wi
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128 Electrical storage heatingWet c
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130 Electrical storage heatingStora
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132 Electrical storage heatingCasin
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134 Electrical storage heatingFinis
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136 Electrical storage heatingTable
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138 Electrical storage heatingVentI
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140 Electrical storage heatingUtili
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142 Electrical storage heatingExpan
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Chapter 6Indirect heating systemsIt
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146 Indirect heating systemsTable 6
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148 Indirect heating systemsin cont
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150 Indirect heating systemsHGIDEAC
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152 Indirect heating systemsLow tem
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154 Indirect heating systemsColdwat
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156 Indirect heating systemsRadiato
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158 Indirect heating systemsRadiato
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160 Indirect heating systemsCondens
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162 Indirect heating systems200800T
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164 Indirect heating systemssuccinc
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166 Indirect heating systemsTable 6
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168 Indirect heating systemsHigh ve
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170 Indirect heating systemsAs will
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172 Indirect heating systems0.080.0
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174 Indirect heating systems(a)(b)(
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Chapter 7Heat emitting equipmentWit
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178 Heat emitting equipmentTable 7.
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180 Heat emitting equipmentRadiant
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Page 203 and 204: 186 Heat emitting equipmentpipes: e
Page 205 and 206: 188 Heat emitting equipmentOpen fro
Page 207 and 208: 190 Heat emitting equipment(a)(b)(d
Page 209 and 210: 192 Heat emitting equipmentTable 7.
Page 211 and 212: 194 Heat emitting equipmentConvecti
Page 213 and 214: 196 Heat emitting equipmentDamperOu
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Page 219 and 220: 202 Heat emitting equipmentcovered
Page 221 and 222: 204 Pumps and other auxiliary equip
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Page 253 and 254: 236 Piping design for indirect heat
Page 277 and 278: Chapter 10Boilers and firing equipm
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Page 283 and 284: 266 Boilers and firing equipment100
Page 285 and 286: 268 Boilers and firing equipmentAs
Page 287 and 288: 270 Boilers and firing equipmentFlu
Page 289 and 290: 272 Boilers and firing equipmentFlo
Page 291 and 292: 274 Boilers and firing equipmentFig
Page 293 and 294: 276 Boilers and firing equipmentof
Page 295 and 296: 278 Boilers and firing equipment. a
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Page 299 and 300: 282 Boilers and firing equipmentFue
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284 Boilers and firing equipmentNoz
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286 Boilers and firing equipmentof
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288 Boilers and firing equipmentNea
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290 Boilers and firing equipmentpor
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292 Boilers and firing equipmentSaf
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294 Boilers and firing equipmentIgn
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Chapter 11Fuels, storage and handli
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298 Fuels, storage and handlingvehi
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300 Fuels, storage and handlingRese
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302 Fuels, storage and handlingtank
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304 Fuels, storage and handlingTank
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306 Fuels, storage and handlingabcd
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308 Fuels, storage and handlingTabl
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314 Fuels, storage and handlingstor
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318 Combustion and chimneysTable 12
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320 Combustion and chimneysTable 12
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322 Combustion and chimneysHence, b
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324 Combustion and chimneys. The te
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326 Combustion and chimneys. Draugh
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328 Combustion and chimneysClean Ai
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330 Combustion and chimneysMechanic
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332 Combustion and chimneysFire bri
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334 Combustion and chimneysMaterial
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336 Combustion and chimneysCombusti
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338 Combustion and chimneysFlueterm
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Chapter 13VentilationThe act or art
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342 VentilationTable 13.1 Ventilati
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344 Ventilationnormal circumstance
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346 Ventilationof air which could b
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348 Ventilationsimilar plant. This
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350 VentilationFlueCrackleaksInduce
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352 VentilationCapSuction bandLouvr
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354 VentilationTable 13.6 Air volum
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356 VentilationCowlBelt driveHinged
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358 VentilationTo fans at roof leve
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360 Ventilationboiler plant in wint
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Dining hall362 VentilationCafeteria
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364 Ventilationthis arrangement, as
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366 Ventilationbe noted that, as a
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368 VentilationTable 13.9 Air veloc
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370 Ventilationvelocity. An increas
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372 VentilationLastly under this he
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374 Air-conditioningBecause refurbi
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376 Air-conditioningThe installatio
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378 Air-conditioningThe type of sys
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380 Air-conditioningAn extension of
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382 Air-conditioningZone unitsSuppl
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384 Air-conditioningSupply airOptio
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386 Air-conditioningoutput of the c
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388 Air-conditioningDischargeto spa
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390 Air-conditioningAirdischargeExt
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392 Air-conditioningin the wall in
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394 Air-conditioningPrimaryair2 Pip
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396 Air-conditioningThe induction s
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398 Air-conditioningsensor as an en
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400 Air-conditioningfan-coil system
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402 Air-conditioningVariable refrig
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404 Air-conditioningChilled water P
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406 Air-conditioningAir supply to h
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408 Air-conditioningTable 14.1 Fact
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410 Air distributionUpward systemTh
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412 Air distributionInlet at 50ºCm
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414 Air distributionExtract airSupp
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416 Air distributioninlet is at a h
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418 Air distribution(a)(b)Figure 15
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420 Air distributionconnections to
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422 Air distributionOpposed bladesD
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424 Air distributionVelocity profil
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426 Air distributionAir supplyPerfo
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428 Air distributionair temperature
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430 Air distributionTable 15.4 Typi
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432 Air distributionFrameSpring cli
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434 Air distributionenergy consumpt
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Chapter 16Ductwork designHaving dec
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438 Ductwork designthe duct with no
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440 Ductwork designFlat ovalStandar
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442 Ductwork designconstruction met
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444 Ductwork designDuctlengthDDRDDu
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446 Ductwork design6mm Plate damper
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448 Ductwork design+Pressure0Veloci
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450 Ductwork designatmospheric pres
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452 Ductwork designTable 16.2 Corre
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454 Ductwork design. Any allowances
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456 Ductwork designBy these means,
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458 Ductwork designTable 16.7 Minim
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460 Ductwork designxAmplitudeyFigur
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462 Ductwork designNoise criteriaIt
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464 Ductwork designL w ˆ 10 ‡ 10
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466 Ductwork design3 64Plant527 8 3
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468 Ductwork designwhereD ˆ perime
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470 Ductwork designArrows show dire
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472 Ductwork designALNORAJAFLOW(a)(
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Chapter 17Fans and air treatment eq
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476 Fans and air treatment equipmen
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PressurePowerPowerPressure482 Fans
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Chapter 18Calculations for air-cond
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Figure 18.1 Psychrometric chart (as
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518 Calculations for air-conditioni
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20mFoyer520 Calculations for air-co
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Chapter 19Refrigeration: water chil
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Absolute pressure MPa532 Refrigerat
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534 Refrigeration: water chillers a
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564 Hot water supply systemsObvious
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566 Hot water supply systemswith a
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568 Hot water supply systemswhich i
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600m m M in570 Hot water supply sys
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572 Hot water supply systemsThe meg
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574 Hot water supply systemsVentDra
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576 Hot water supply systemsPrimary
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578 Hot water supply systemsCistern
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580 Hot water supply systemsFor use
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582 Hot water supply systemsSteam-t
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584 Hot water supply systemsThe hea
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586 Hot water supply systemsTable 2
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588 Hot water supply systemsStorage
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590 Hot water supply systemsStorage
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592 Hot water supply systemsadequat
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594 Hot water supply systemsA compl
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596 Hot water supply systemsInsulat
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Chapter 21Piping design for central
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600 Piping design for central hot w
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Water flow rate in energy units kW/
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Chapter 22Automatic controls and bu
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622 Automatic controls and building
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660 Running costsPence per kWh4.03.
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662 Running costsAfter allowance ha
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664 Running costsTable 23.3 Part L
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666 Running costsTable 23.4 Degree-
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668 Running costsTable 23.5 Approxi
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670 Running costsaddition, consider
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672 Running costsRunning hours for
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674 Running costs20%. The variables
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Air temperature (ºC)Mass flow rate
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678 Running costsEnergy auditsAn en
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680 Running costs. Preventative. Pl
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682 Running costsTable 23.14 Econom
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3Oil consumption(litre / month x 10
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686 Running costsTable 23.15 Presen
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Chapter 24Combined heat and power (
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690 Combined heat and power (CHP)Fi
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698 Combined heat and power (CHP)to
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700 Combined heat and power (CHP)we
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Appendix ITemperature levelsDegrees
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Appendix IIIConversion factorsImper
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708 IndexAuxiliaryequipment (costs)
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710 Indexdegree-hour 676heat pumps
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712 Indexcleaning 489±93, 489±93d
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714 IndexIndirect hot water supplys
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716 IndexPharmaceuticalcleanrooms 4
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718 IndexSol-air temperatures 12sol
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720 Indexextract grilles 430±1indu
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