Calculation sequence
Step-by-step method
- Convert I-P refrigeration tons to thermal kW when required.
- Divide useful thermal capacity by electrical input power.
- Convert COP to EER for reference.
MechanicalBeginnerEquipment
Coefficient of Performance Calculator
Calculate equipment COP from useful thermal capacity and electrical input power.
Why it matters: COP places thermal output and electrical input on the same energy-rate basis.
Calculated result
Engineering evaluation
Coefficient of performance (COP)3.517 ratio
- Useful thermal capacity (QkW)
- 351.7 kW
- Energy-efficiency ratio (EER)
- 12 Btu/(Wh)
Engineering interpretation
The entered operating point has COP 3.517 and EER 12 Btu/(Wh).
Important limitations
- Keep capacity and power boundaries consistent. Include pumps, fans, towers, controls, or auxiliaries only when the stated performance boundary requires them.
Engineering knowledge center
Understand the calculation—not just the answer
Governing relationships
QkW = Q·3.51685284
COP = QkW/P
EER = 3.412142·COP
Current substitution
QkW = 351.7 kW; COP = 351.7/100 = 3.517; EER = 12.
Equation legend
Inputs and calculated quantities
- Q
- Useful thermal capacity — ton or kW
- P
- Electrical input power — kW
- COP
- Coefficient of performance — ratio
- QkW
- Useful thermal capacity — kW
- EER
- Energy-efficiency ratio — Btu/(Wh)
Applications
How this calculation is used
Building design
Compare scheduled thermal capacity and input power.
Construction
Check nameplate and submittal performance points.
Commissioning
Calculate field COP using simultaneous capacity and power measurements.
Quality controls
Assumptions and limitations
Assumptions
- Entered values represent one stable operating condition and use consistent measurement boundaries.
- Fluid and air properties are representative of the evaluated condition.
Limitations
- This is a preliminary evaluation and field-verification tool, not a final sizing or code-compliance determination.
- Manufacturer data, adopted codes, project criteria, and professional engineering review remain controlling.
Field use
Verification procedure
- Confirm measurement boundaries, operating mode, and instrument calibration.
- Stabilize the system and record simultaneous readings.
- Compare the calculation with project requirements and manufacturer data before disposition.
Common engineering mistakes
- Mixing values from different operating conditions.
- Using nominal rather than measured flow, temperature, power, or fluid properties.
Technical basis
References and source standards
- U.S. Department of Energy—Better Buildings Solution CenterFederal energy-performance and HVAC equipment guidance; project and manufacturer data remain controlling.
- ASHRAE Handbook—FundamentalsPsychrometrics, heat transfer, load relationships, and HVAC calculation context; verify the licensed current edition during professional review.
- NIST Guide for the Use of the International System of UnitsFederal unit-system and conversion reference used for SI/I-P presentation.
Engineering calculation disclaimer
These engineering tools are provided for educational, preliminary evaluation, field verification, and commissioning support. Results depend on the accuracy of user-entered information and the assumptions stated for each calculation. Every colored status and comparison is a screening indicator only; project criteria, contract requirements, applicable codes, manufacturer instructions, measurement uncertainty, and authorized engineering judgment govern. The tools do not replace project-specific engineering analysis or the judgment of a licensed professional engineer.
Read the full use and limitation statement