Page 372 - Defrosting for Air Source Heat Pump

Index

Note: Page numbers followed by f indicate figures and t indicate tables.

A refrigerant mass flow rate, 101–102,
Absorption heat pumps, 1 103f, 105–106f
Air jet technique, 17, 345 surface tension on, 138
Air source heat pump (ASHP) unit tube surface temperature, 101, 102f,
control strategy optimization, 345 104–106, 107–108f
defrosting methods with two refrigerant circuits, 48–51, 48f,
compressor shutdown, 23–25, 27t 49t,50–51f
electric heating, 25–26, 27t
C
frost suppression vs.,25t
hot gas bypass, 26, 27t Carnot cycle, 11
hot water spraying, 26, 27t Clean development mechanism (CDM), 115
reverse cycle, 26–28, 27t Coefficient of performance (COP), 1, 163f,
energy transfer mechanism, 224 164
local drainage of melted frost, 242 Compression heat pumps, 1
mechanism study, 345 Compressor shutdown defrosting (CSDD)
melted frost elimination, on uneven method, 23–25, 27t
defrosting, 118–121, 120t Convective heat transfer, 77
model development, 345 Convective heat transfer coefficient, 78
multicircuit outdoor coil, 155–156 CSDD. See Compressor shutdown defrosting
new methods and materials, 345 (CSDD) method
outdoor coil, 5–7
refrigerant distribution, melted frost D
flowing, 204 DAS. See Data-acquisition system
running cost (see Running cost, ASHP unit) (DAS)
surface tension, on uneven defrosting, 138 Data-acquisition system (DAS), 96, 119–121
system and component optimization, 345 Data analysis and validation, defrosting
uneven defrosting, 95–110 control strategy
airside of three-circuit outdoor coil, 98, DTT periods and nodes, 296–298
98f experimental results, 290
assumptions, 102–103 RCD termination temperature, 299–300
defrosting durations, 104, 104t tube surface temperature analysis, 290
experimental cases, 99–100, 100t, DEC. See Defrosting evenness coefficient
100f (DEC)
experimental study, 96–98 Defrosting, 3–5
heat supply and energy consumption, demand-based, 35
108–110, 109f efficiency, 67
melted frost elimination on, 118–121, methods
120t compressor shutdown, 23–25, 27t
modeling study, 98–99 electric heating, 25–26, 27t
outdoor coil, 96, 97f frost suppression vs.,25t
refrigerant distribution, 100f, 101 hot gas bypass, 26, 27t