Page 374 - Defrosting for Air Source Heat Pump

Index 371

MES effects, 241–242, 252 heat supplies, 237f
temperature variations, 249–251, 249f local drainage of melted frost, 241–253
MES calculations, 231 MES calculations, 231
MES effect, 241t and MES effect, 241t
precalibrated K-type thermocouples, precalibrated K-type thermocouples,
229–230 229–230
prototypical three-circuit indoor coil, 227t prototypical three-circuit indoor coil,
refrigerant distribution 227t
energy analysis, 202–204 tailor-made three-circuit outdoor coil,
experimental cases, 194–197 227t
experimental results, 197–202 temperature differences, indoor and
tailor-made three-circuit outdoor coil, 227t outdoor coils, 234–235
temperature differences, indoor and temperature values, 239–240
outdoor coils, 234–235 three-circuit outdoor coil, 225
temperature values, 239–240 three water-collecting cylinders, 228
three-circuit outdoor coil, 225 three-working-circuit outdoor coils, 241
three water-collecting cylinders, 228 total mass of frost accumulation, 228
three-working-circuit outdoor coils, 241 two-working-circuit, 225, 241
total mass of frost accumulation, 228 dynamic energy transfer, 223–224
two-working-circuit, 225, 241 measured tube surface temperature of
Defrosting termination temperature (DTT), outdoor coil circuit, 234f
36–37, 37t melted frost, effects of, 223, 253
Demand-based defrosting, 35 periodic defrosting, 223
Direct expansion air-conditioning system performance improvement, 223
(DX A/C) system, 50 thermal comfort, 254–255
Dittus-Boelter correlation, 78 vaporize melted frost, 223
Downward-flowing melted frost, 343 Environmental chamber, 50, 50f, 118,
Dry-bulb temperature sensors, 119 155–156
Even frosting, 204–205
E
Electric heating defrosting (EHD), 25–26, 27t F
Electronic expansion valve (EEV), 214–215 FEC. See Frosting evenness coefficient (FEC)
Energy performance improvement, 304 Fin surface, coating treatment on, 18–19,
Energy transfer mechanism, 344 20–21t
airside surface conditions of Fin-type adjustment, 18
outdoor coil, 232–233 Fraction force (Ff), 123
ASHP unit, 224 Frost accumulation, 153–154, 154f
defrosting duration and defrosting Frost deposition, 3–4
efficiency, 223 Frost formation, on cold flat plate surface,
defrosting performance 3–4, 3f
air wet-bulb temperatures, 229–230 Frosting evenness coefficient (FEC), 350
defrosting efficiency, 225 defrosting performances, 164–175
energy input, to compressor, 236f airside surface conditions of
energy supplies and consumptions, 225 outdoor coil, 166–167, 166f
experimental cases, 230 defrosting durations, 171–172, 174t,
experimental results, 239t 174f
experimental setup, 225 defrosting efficiency, 174–175, 174f
heat consumptions, 238f, 240 differential analysis, 174t