Page 196 - Defrosting for Air Source Heat Pump

190 Defrosting for Air Source Heat Pump

The power input to compressor The power input to indoor air fan The energy from the indoor air
15.42% 14.9% 16.91%
0.95% 0.9%
120.6 kJ 112.2 kJ 114.8 kJ 0.37%
7.4 kJ 6.8 kJ 2.5 kJ

653.8 kJ 634.3 kJ 561.5 kJ

83.63% 84.2% 82.72%
(A) (B) (C)
Energy consumption on vaporizing the retained water Energy consumption on melting frost
5.14% 4.33% 5.96%
18.1 kJ 15.9 kJ 20.5 kJ

334.0 kJ 351.4 kJ 323.6 kJ

(D) 94.86% (E) 95.67% (F) 94.04%

Fig. 6.39 Energy supplies for defrosting and consumptions during defrosting. (A, D) Case 1,
(B, E) Case 2, (C, F) Case 3.

260 54
Defrosting duration Fin Refrigerant
Melted frost collected Defrosting efficiency
240 52

220 50
23 s
200 5.7% 48
22 s
Time (s) 180 10 s 46 Defrosting efficiency (%)

160 44
22 s
140 42
120 40
Case 1 (79.4%) Case 2 (91.2%) Case 3 (96.6%)
100 38
78 80 82 84 86 88 90 92 94 96 98
FECs (%)
Fig. 6.40 Different durations and defrosting efficiency in the three cases.