Building Services Engineering 5th Edition Handbook

More documents

Recommendations

Info

Electrical installations 295 temperature would reveal a straight line of slope α. R 40 = R 20 (1 + α × 20) = 0.0069 × (1 + 0.00428 × 20) = 0.0075 The relation between applied voltage, electric current and resistance is given by Ohm’s law: I amps = V volts R ohms Figure 13.3 shows how an ammeter and a voltmeter are connected into a circuit to measure power consumption. The load may be an electrical resistance heater or tungsten filament lamp, in which case the power consumption in watts is found from: power in watts = V volts × A amps × cos φ for single-phase and, power in watts = V volts × A amps × √ 3 × cos φ for three-phase, where cos φ is the power factor (zero to unity). An electrical resistance heater and tungsten lamps are purely resistive loads whose power factor, cos φ, is unity, 1. Loads such as electric motors and fluorescent lamps have a property known as inductance, which causes the current to lag behind the voltage that is producing that current. This is due to an electromotive force (emf), that is, a voltage which opposes the incoming emf. The densely packed electromagnetic windings of a motor have a high inductance and thus the 50 Hz cyclic variation of voltage and current is opposed by the ‘inertia’ of the equipment. The opposing emf comes from the expanding and collapsing magnetic fields of the input power around the conductors. The lag angle φ ◦ between peak voltage and peak current means that the instantaneous available power is less than the product of the two peaks. Figure 13.4 shows voltage applied across a circuit creating a current that lags in real time; peak current occurs after the peak voltage. Fuse A Ammeter Alternating current supply Voltmeter V Load 13.3 Measurements of power consumption in an electrical circuit.
296 Electrical installations 1 Voltage V volts V max I max Relative voltage and current 0 Voltage leads current by phase angle 15 degrees, so power factor is cos 15 = 0.96 Current Iamps Current lags voltage in time –1 0 45 90 135 180 225 270 315 360 Phase angle, degrees 13.4 Phase angle lag. Power factor is the term used to differentiate between useful output power in watts and the input instantaneous product of voltage and current to the load: useful power in watts watts power factor PF = = input volts × amps volt × amps real power (to do work) = apparent power PF = kW kVA = kilowatts kilovolt-amps = kW real kVA (apparent) Figure 13.5 shows all three phases as they occur in real time, separated by 120 ◦ phase angle. Because of the three voltage sine waves within each cycle, the overall power generated is higher and smoother than with only a single-phase motor. Capacitors have an electrical storage capability, which is used to overcome the effects of inductance. Power factors of electrical equipment are commonly 0.85 and these can be improved to 0.95 by the addition of power-factor-correcting capacitors. Several loads to a circuit may be connected either in series or in parallel with each other. For series-connected resistances: R = R 1 + R 2 + R 3 +···
Page 2 and 3:
Building Services Engineering
Page 4 and 5:
Building Services Engineering Fifth
Page 6 and 7:
Contents Preface to fifth edition A
Page 8 and 9:
Contents vii Sick building syndrome
Page 10 and 11:
Contents ix Circuit design 294 Cabl
Page 12 and 13:
Preface to fifth edition Building S
Page 14 and 15:
Acknowledgements I am particularly
Page 16 and 17:
Units and constants xv Table 2 Mult
Page 18 and 19:
Symbols xvii Symbol Description Uni
Page 20:
Symbols xix Symbol Description Unit
Page 23 and 24:
2 Built environment Introduction Th
Page 25 and 26:
4 Built environment Ventilation The
Page 27 and 28:
6 Built environment (a) At full occ
Page 29 and 30:
8 Built environment Table 1.2 Compa
Page 31 and 32:
10 Built environment Because of the
Page 33 and 34:
12 Built environment Visual display
Page 35 and 36:
14 Built environment v = 7 m/s t a
Page 37 and 38:
16 Built environment 1.4 Sling psyc
Page 39 and 40:
18 Built environment 1.7 Thermistor
Page 41 and 42:
20 Built environment t res = t g (1
Page 43 and 44:
22 Built environment great care wit
Page 45 and 46:
24 Built environment 16. An hotel l
Page 47 and 48:
26 Built environment 37. Are any of
Page 49 and 50:
28 Built environment building has a
Page 51 and 52:
30 Built environment 73. What was t
Page 53 and 54:
32 Energy economics Introduction Bu
Page 55 and 56:
34 Energy economics 16. air-to-air
Page 57 and 58:
36 Energy economics 1 kWh = 1 kWh
Page 59 and 60:
38 Energy economics 2. Heat transfe
Page 61 and 62:
40 Energy economics For solid fuel
Page 63 and 64:
42 Energy economics gas cost = 1.80
Page 65 and 66:
44 Energy economics Table 2.5 Carbo
Page 67 and 68:
46 Energy economics EXAMPLE 2.8 A h
Page 69 and 70:
48 Energy economics annual cost = u
Page 71 and 72:
50 Energy economics EXAMPLE 2.12 Ex
Page 73 and 74:
52 Energy economics l = 0.035 ( 1 0
Page 75 and 76:
54 Energy economics Table 2.11 Valu
Page 77 and 78:
56 Energy economics From Table 2.4
Page 79 and 80:
58 Energy economics 3. Minimum outs
Page 81 and 82:
3 Heat loss calculations Learning o
Page 83 and 84:
62 Heat loss calculations Table 3.1
Page 85 and 86:
64 Heat loss calculations Table 3.6
Page 87 and 88:
66 Heat loss calculations Where onl
Page 89 and 90:
68 Heat loss calculations The venti
Page 91 and 92:
70 Heat loss calculations The surro
Page 93 and 94:
72 Heat loss calculations The speci
Page 95 and 96:
74 Heat loss calculations where R m
Page 97 and 98:
76 Heat loss calculations The addit
Page 99 and 100:
78 Heat loss calculations operation
Page 101 and 102:
80 Heat loss calculations 2. The fo
Page 103 and 104:
82 Heat loss calculations internal
Page 105 and 106:
84 Heat loss calculations 27. Which
Page 107 and 108:
86 Heating Key terms and concepts a
Page 109 and 110:
88 Heating 4.2 Electrically heated
Page 111 and 112:
90 Heating Sheet steel case Removab
Page 113 and 114:
92 Heating Floor finish Screed with
Page 115 and 116:
94 Heating Flue Return air plenum F
Page 117 and 118:
96 Heating Table 4.1 Classification
Page 119 and 120:
98 Heating Table 4.2 Heat output fr
Page 121 and 122:
100 Heating Table 4.3 Flow of water
Page 123 and 124:
102 Heating and, maximum available
Page 125 and 126:
104 Heating This means that one vol
Page 127 and 128:
106 Heating Performance testing A r
Page 129 and 130:
108 Heating Electrical power genera
Page 131 and 132:
110 Heating Combined heat and power
Page 133 and 134:
112 Heating 3. A building energy ma
Page 135 and 136:
114 Heating Connections are made to
Page 137 and 138:
116 Heating remotely the MWh consum
Page 139 and 140:
118 Heating 13. The two-pipe heatin
Page 141 and 142:
120 Heating 27. Which is not correc
Page 143 and 144:
122 Heating 39. Which of these is t
Page 145 and 146:
124 Heating 4. Heat supplied is cha
Page 147 and 148:
126 Ventilation and air conditionin
Page 149 and 150:
Page 151 and 152:
Page 153 and 154:
Page 155 and 156:
Page 157 and 158:
Page 159 and 160:
Page 161 and 162:
Page 163 and 164:
Page 165 and 166:
Page 167 and 168:
Page 169 and 170:
Page 171 and 172:
Page 173 and 174:
Page 175 and 176:
Page 177 and 178:
Page 179 and 180:
Page 181 and 182:
Page 183 and 184:
Page 185 and 186:
Page 187 and 188:
Page 189 and 190:
Page 191 and 192:
Page 193 and 194:
Page 195 and 196:
Page 197 and 198:
Page 199 and 200:
6 Hot- and cold-water supplies Lear
Page 201 and 202:
180 Hot- and cold-water supplies Wa
Page 203 and 204:
182 Hot- and cold-water supplies po
Page 205 and 206:
184 Hot- and cold-water supplies Ce
Page 207 and 208:
186 Hot- and cold-water supplies st
Page 209 and 210:
188 Hot- and cold-water supplies 0.
Page 211 and 212:
190 Hot- and cold-water supplies 53
Page 213 and 214:
192 Hot- and cold-water supplies an
Page 215 and 216:
194 Hot- and cold-water supplies Ta
Page 217 and 218:
196 Hot- and cold-water supplies Ta
Page 219 and 220:
198 Hot- and cold-water supplies (a
Page 221 and 222:
Page 223 and 224:
Page 225 and 226:
204 Hot- and cold-water supplies 49
Page 227 and 228:
206 Soil and waste systems Introduc
Page 229 and 230:
208 Soil and waste systems Open to
Page 231 and 232:
210 Soil and waste systems 7. Bends
Page 233 and 234:
212 Soil and waste systems The inte
Page 235 and 236:
214 Soil and waste systems 40 mm wa
Page 237 and 238:
216 Soil and waste systems Table 7.
Page 239 and 240:
218 Soil and waste systems 50 mm ve
Page 241 and 242:
220 Soil and waste systems 3. Long
Page 243 and 244:
222 Surface-water drainage Table 8.
Page 245 and 246:
224 Surface-water drainage Rectangu
Page 247 and 248:
226 Surface-water drainage The solu
Page 249 and 250:
228 Surface-water drainage 7. A PVC
Page 251 and 252:
230 Below-ground drainage Design ca
Page 253 and 254:
232 Below-ground drainage Manhole:
Page 255 and 256:
234 Below-ground drainage From Fig.
Page 257 and 258:
236 Below-ground drainage storage v
Page 259 and 260:
238 Below-ground drainage 14. The f
Page 261 and 262:
240 Condensation in buildings mould
Page 263 and 264:
242 Condensation in buildings The w
Page 265 and 266: 244 Condensation in buildings EXAMP
Page 267 and 268: 246 Condensation in buildings This
Page 269 and 270: 248 Condensation in buildings Tempe
Page 271 and 272: 250 Condensation in buildings and,
Page 273 and 274: 252 Condensation in buildings EXAMP
Page 275 and 276: 254 Condensation in buildings Tempe
Page 277 and 278: 256 Condensation in buildings For t
Page 279 and 280: 258 Condensation in buildings 4. Ev
Page 281 and 282: 11 Lighting Learning objectives Stu
Page 283 and 284: 262 Lighting Table 11.1 Typical val
Page 285 and 286: 264 Lighting Light sources 9 9 9 Wi
Page 287 and 288: 266 Lighting Utilization factor The
Page 289 and 290: 268 Lighting From Table 11.3, for a
Page 291 and 292: 270 Lighting Table 11.4 Lamp data.
Page 293 and 294: 272 Lighting number of lamps = 12.8
Page 295 and 296: 274 Lighting 3. Sketch and describe
Page 297 and 298: 276 Lighting 4. Insufficient inform
Page 299 and 300: 278 Lighting 3. 800 lm/m 2 . 4. 260
Page 301 and 302: 12 Gas Learning objectives Study of
Page 303 and 304: 282 Gas Open to atmosphere Rubber p
Page 305 and 306: 284 Gas EL = (1.25 × 34) m = 42.5
Page 307 and 308: 286 Gas become exhausted. SNG will
Page 309 and 310: 288 Gas are ignited and an air flow
Page 311 and 312: 290 Gas 3. The pipe from a gas mete
Page 313 and 314: 292 Electrical installations Key te
Page 315: 294 Electrical installations curren
Page 319 and 320: 298 Electrical installations power
Page 321 and 322: 300 Electrical installations For1mm
Page 323 and 324: 302 Electrical installations Table
Page 325 and 326: 304 Electrical installations Incomi
Page 327 and 328: 306 Electrical installations energi
Page 329 and 330: 308 Electrical installations Starte
Page 331 and 332: 310 Electrical installations Ethyle
Page 333 and 334: 312 Electrical installations Test o
Page 335 and 336: 314 Electrical installations Joint
Page 337 and 338: 316 Electrical installations 4. 100
Page 339 and 340: 318 Electrical installations 39. Wh
Page 341 and 342: 320 Electrical installations 51. Wh
Page 343 and 344: 322 Room acoustics 20. understand t
Page 345 and 346: 324 Room acoustics pump blades and
Page 347 and 348: 326 Room acoustics ceiling, Q is 4.
Page 349 and 350: 328 Room acoustics Table 14.2 Solut
Page 351 and 352: 330 Room acoustics Table 14.3 Fan s
Page 353 and 354: 332 Room acoustics Table 14.4 Illus
Page 355 and 356: 334 Room acoustics (Sound Research
Page 357 and 358: 336 Room acoustics The target room
Page 359 and 360: 338 Room acoustics Table 14.6 Noise
Page 361 and 362: 340 Room acoustics 100 90 80 70 Sou
Page 363 and 364: 342 Room acoustics 24. A forced-dra
Page 365 and 366: 344 Room acoustics The room directi
Page 367 and 368:
346 Room acoustics 3. Multiple sour
Page 369 and 370:
348 Room acoustics 55. Which is not
Page 371 and 372:
350 Fire protection computer monito
Page 373 and 374:
352 Fire protection halogen gas, wh
Page 375 and 376:
354 Fire protection the reach of tu
Page 377 and 378:
356 Fire protection Range pipe Spri
Page 379 and 380:
358 Fire protection Fire compartmen
Page 381 and 382:
360 Fire protection 16. Which are c
Page 383 and 384:
362 Plant and service areas Key ter
Page 385 and 386:
364 Plant and service areas 2.0 1.5
Page 387 and 388:
366 Plant and service areas Fuel st
Page 389 and 390:
368 Plant and service areas a minim
Page 391 and 392:
370 Plant and service areas An unde
Page 393 and 394:
372 Plant and service areas Air cha
Page 395 and 396:
374 Plant and service areas 100 mm
Page 397 and 398:
376 Plant and service areas Fire co
Page 399 and 400:
378 Plant and service areas Table 1
Page 401 and 402:
380 Plant and service areas 11. Wha
Page 403 and 404:
17 Mechanical transportation Learni
Page 405 and 406:
384 Mechanical transportation Table
Page 407 and 408:
386 Mechanical transportation Crowd
Page 409 and 410:
388 Mechanical transportation Hydra
Page 411 and 412:
390 Mechanical transportation 4. Co
Page 413 and 414:
18 Question bank Learning objective
Page 415 and 416:
394 Question bank 8. Which correctl
Page 417 and 418:
396 Question bank 5. This building
Page 419 and 420:
398 Understanding units Questions 1
Page 421 and 422:
400 Understanding units 15. Which i
Page 423 and 424:
402 Understanding units 29. Which o
Page 425 and 426:
404 Understanding units 43. Which i
Page 427 and 428:
Appendix: answers to questions Chap
Page 429 and 430:
408 Appendix Chapter 3 Heat loss ca
Page 431 and 432:
410 Appendix 4. 0.007469 kg H 2 O/k
Page 433 and 434:
412 Appendix 32. 5 33. 5 34. 3 35.
Page 435 and 436:
414 Appendix 23. Lighting 1200 h/ye
Page 437 and 438:
416 Appendix 27. 37 dB. 28. 39 dB.
Page 439 and 440:
418 Appendix 15. 5 16. 2 17. 5 18.
Page 441 and 442:
References Action Energy, Departmen
Page 443 and 444:
Index Absorption 154, 324 Absorptio
Page 445 and 446:
424 Index Gas burner controls 289 G
Page 447 and 448:
426 Index Sensible heat gains 137 S
show all

Building Services Engineering 5th Edition Handbook

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?