Table:
text: Heat pump
Performance
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  2.2 2.0 ‐ ‐ ‐ ‐
Two-stage ASHP, air at −20 °C Low source temperature 2.4 2.2 1.9 ‐ ‐ ‐
High efficiency ASHP, air at 0 °C 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 High output temperature 3.3 ‐ ‐ 4.2 ‐ 3.0
Ground source heat pump (GSHP), water at 0 °C  5.0 3.7 2.9 2.4 ‐ ‐

text: Heat pump
Performance
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_
GSHP, ground at 10 °C 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  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

Question: Which pump had the best range of fluctuation at 35 degrees Celsius among the heat pumps?