Page 373 - Defrosting for Air Source Heat Pump

370 Index

Defrosting (Continued) flow chart of procedure, 261f
hot water spraying, 26, 27t fluctuation of tube surface temperature,
reverse cycle, 26–28, 27t 264–265f
Defrosting control strategy frost accumulation, 260, 272f
artificial intelligence, 257 indoor coil air temperature difference,
frost accumulation, 257–258 fluctuation of, 269f
holographic interferometry technique, melted frost, fluctuation of, 266f
257–258 outdoor coil airside surface conditions,
infrared thermometer, 257–258 262–263, 262–263f
initiation, 35–36 refrigerant pressure difference,
Internet of Things, 257 fluctuation of, 267f
melted frost, local drainage of refrigerant volumetric flow rate,
compressor suction and discharge, fluctuation of, 266f
measured pressures of, 279–280, trial-and-error manual adjustments, 260
281f unequal frost accumulation, 258
durations of melted frost, 281t Yao’s distributed mathematical frosting
energy supply and effective energy model, 257–258
consumption, 281–283, 283f Defrosting duration, 343
flow chart, 274f Defrosting efficiency, 225, 343
frost accumulation, 274, 284f calculation error, 348
frosting durations, p0110 definition, 347
indoor air thermal and electricity, energy transfer mechanism, 223, 225
280–281, 282f frosting evenness coefficient, 174–175,
mal-defrosting problems, 273 174f, 189, 190f
measured temperatures, 278–279, 280f metal energy storage effect, 349
outdoor coil airside surface conditions, technoeconomic performances, 303
275–276, 276f uneven defrosting, on outdoor coil, 67
preheating stage of, 275–277 Defrosting evenness coefficient (DEC), 132,
pressure difference between suction and 133t, 351
discharge, 279–280, 282f Defrosting evenness status, 343
refrigerant distribution resistance, Defrosting performance, 344
278–279 air wet-bulb temperatures, 229–230
system stability and indoor thermal defrosting efficiency, 225
comfort, 284–285 energy input, to compressor, 236f
trial-and-error manual adjustments, 274 energy supplies and consumptions, 225
termination of, 36–38 experimental cases, 230
data analysis and validation, 290–300 experimental results, 239t
enhanced heat transfer efficiency, experimental setup, 225
285–286 heat consumptions, 238f, 240
experimental cases, 288–290 heat supplies, 237f, 250f
methodology, 286–287 local drainage of melted frost
minimized refrigerant pressure loss, airside surface conditions of outdoor
285–286 coil, 245
surface temperature of outdoor coil, air temperature differences, 246–249
285–286 ASHP unit, 242
time-based defrosting initiation control experimental cases, 242–243
strategy, 258 heat consumption, 252
DX A/C system, 260–261 mean measured tube surface
energy supply and, 271f temperatures, 247–248f