Calculate the annual thermal capacity factor of a heat pump system by comparing measured or modeled useful output with the maximum output possible at rated capacity. The result also shows equivalent full-load hours and the difference from continuous rated operation, making utilization easier to review without confusing it with COP or electrical efficiency.
Capacity factor describes utilization of rated thermal capacity across the period. It does not directly grade system efficiency, because a lightly loaded system can have a low capacity factor and still operate efficiently.
Use consistent thermal units. For a leap year, 8,784 hours may be appropriate; otherwise a full calendar year normally has 8,760 hours.
For 20,000 kWh of annual useful heat from a 10 kW unit over 8,760 hours, maximum output is 87,600 kWh. Capacity factor is 22.8%, equal to 2,000 full-load hours.
It compares actual useful thermal output with output at continuous rated capacity over the selected hours.
No, not when thermal output, rated thermal capacity, and hours use consistent definitions.
No. Capacity factor measures utilization over time; COP measures heat delivered per unit of electricity.
Use the rating that matches the annual output being analyzed.
They express the same utilization as an equivalent number of hours at rated capacity.
| Output basis | Relationship |
|---|---|
| 0% factor | No useful output during the period |
| Full-load hours | Capacity factor × period hours |
| Maximum output | Rated capacity × period hours |
| COP | Separate efficiency measure, not utilization |