COP variation with output temperature
Pump type and source |
Typical use |
35 °C
(e.g. heated screed floor) |
45 °C
(e.g. heated screed floor) |
55 °C
(e.g. heated timber floor) |
65 °C
(e.g. radiator or DHW) |
75 °C
(e.g. radiator and DHW) |
85 °C
(e.g. radiator and DHW) |
High-efficiency air source heat pump (ASHP), air at −20 °C[5] |
|
2.2 |
2.0 |
‐ |
‐ |
‐ |
‐ |
Two-stage ASHP, air at −20 °C[6] |
Low source temperature |
2.4 |
2.2 |
1.9 |
‐ |
‐ |
‐ |
High efficiency ASHP, air at 0 °C[5] |
Low output temperature |
3.8 |
2.8 |
2.2 |
2.0 |
‐ |
‐ |
Prototype transcritical CO
2 (R744) heat pump with tripartite gas cooler, source at 0 °C[7] |
High output temperature |
3.3 |
‐ |
‐ |
4.2 |
‐ |
3.0 |
Ground source heat pump (GSHP), water at 0 °C[5] |
|
5.0 |
3.7 |
2.9 |
2.4 |
‐ |
‐ |
GSHP, ground at 10 °C[5] |
Low output temperature |
7.2 |
5.0 |
3.7 |
2.9 |
2.4 |
‐ |
Theoretical Carnot cycle limit, source −20 °C |
|
5.6 |
4.9 |
4.4 |
4.0 |
3.7 |
3.4 |
Theoretical Carnot cycle limit, source 0 °C |
|
8.8 |
7.1 |
6.0 |
5.2 |
4.6 |
4.2 |
Theoretical Lorentzen cycle limit (CO
2 pump), return fluid 25 °C, source 0 °C[7] |
|
10.1 |
8.8 |
7.9 |
7.1 |
6.5 |
6.1 |
Theoretical Carnot cycle limit, source 10 °C |
|
12.3 |
9.1 |
7.3 |
6.1 |
5.4 |
4.8 |