Page 105 - Defrosting for Air Source Heat Pump

Modeling study on uneven defrosting 97

Heating mode 590 mm
Defrosting mode
44 mm
T i
T i SV 1
Header T i Circuit 1 Circuit 1 152 mm
From T e MV 1
compressor
SV 2
To compressor 22 mm
Circuit 2 Circuit 2
T e MV 2
To EEV 500 mm
SV 3
From EEV
Circuit 3
T e MV 3 Circuit 3
Measuring
Distributor
Water collecting tray cylinder
(A) (slope 37 )

Heating mode 590 mm
Defrosting mode
44 mm
T i
T i SV 1
Header T i Circuit 1 152 mm
From T e MV 1
compressor A
SV 2
To compressor
A 22 mm
T e MV 2 Circuit 2
To EEV
B 500 mm
SV 3
From EEV
B
T e MV 3 Circuit 3
C Measuring
Distributor
cylinder
Water collecting tray C
(B) (slope 37 )
Fig. 4.18 Details of the vertical three-parallel refrigerant circuit outdoor coil without and with a
water-collecting tray installed between circuits. (A) Without water collecting tray installed
between circuits (Case 1 in Section 3.3). (B) With water collecting tray installed between
circuits (Case 3 in Section 3.3).

collected, such as the tube surface temperature at the inlet of each refrigerant circuit,
the refrigerant mass flow rate, the total mass of melted frost collected, etc. Second,
part of the experimental results would be used in the validation stage of the following
two developed models.
However, there are still some limitations in this experimental study. First, some
parameters could not be measured, such as the rate of melted frost downward flowing
along the surface of the outdoor coil. Second, some parameters such as the