Page 176 - Defrosting for Air Source Heat Pump

170 Defrosting for Air Source Heat Pump

32
28
T > T > T
1 2 3 T > T > T
1 3 2
24 Fin in Circuit 1
Temperature of fin surface ( o C) 16 8 Fin in Circuit 2
20
Fin in Circuit 3

12

4
185 s 196 s
0

80 100 120 140 160 180 200 220 240 260
Time (s)

Fig. 6.20 Measured fin surface temperature at the center of three refrigerant circuits during
defrosting in Case 3.

1.8
Case 1 Case 2 Case 3
Measured refrigerant volumetric flow rate (L/M) 1.2 Fluctuating R Case 3 > R Case 2 > R Case 1
1.6
1.4

1.0
0.8
0.6

0.4
0.2
180 s
0.0 174 s 180 s
0 40 80 120 160 200 240
Time (s)

Fig. 6.21 Measured refrigerant volumetric flow rate during defrosting in the three cases.