Coefficient of performance (COP) and balance point

Air Conditioning and Heat Pumps · Heat Pumps in Theory · printed page 227 (PDF page 228)

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Co-efficient of Performance for Heat Pumps Heat Pump – Co-efficient of Performance

Text in the illustration

coefficient of performance
heat pump output
below balance point, heat pump can't keep up
balance point
house heat loss
energy (kw)
COEFFICIENT OF PERFORMANCE
outdoor temperature (°F)
modern heat pumps have COPs greater than 1.0 down to -25°F
0
5
10
15
20
1.0
2.0
3.0
-20°F
-5°F
15°F
32°F
50°F
70°F

Generated explanation

The illustration graphs heat pump output, coefficient of performance (COP), and house heat loss against outdoor temperature. Two solid curves show heat pump output and COP increasing as outdoor temperature rises, while a descending dashed line represents decreasing house heat loss. The balance point is marked where heat pump output equals house heat loss, slightly below 32°F, with a vertical dashed reference line. A shaded region below that outdoor temperature identifies the heating shortfall where the heat pump cannot keep up with house heat loss. A side annotation states that modern heat pumps have COPs greater than 1.0 down to -25°F.

Components

heat pump house