Calculate chilled-water capacity, percent of scheduled capacity, and operating kW per ton or COP-equivalent ratio.
Why it matters: Field capacity and electrical input must be evaluated at the same stable load and water condition.
ΣCALCULATE · VERIFY · INTERPRET
Calculated result
Engineering evaluation
Within entered screening criteria
Measured chiller capacity relative to schedule (PC)100 %
Calculated water-side capacity (Ccalc)
500 tons
Measured evaporator-water temperature drop (ΔT)
10 °F
Chiller specific power (SP)
0.6 kW/ton
Signed capacity deviation (δC)
0 %
Engineering interpretation
Measured water-side capacity is 500 tons (100% of schedule), with 0.6 kW/ton. Evaluate the result at the documented load, entering conditions, flow, and equipment boundary.
Confirm the approved reference values and test boundary.
Stabilize the system and record calibrated field measurements.
Review calculation assumptions, uncertainty, and supporting evidence before disposition.
Common engineering mistakes
Comparing readings taken at different loads, modes, or reference conditions.
Treating a calculated status as proof of code, contract, or manufacturer compliance.
Technical basis
References and source standards
ASHRAE Handbook—FundamentalsCurrent handbook chapters covering fluid flow, thermodynamics, psychrometrics, measurement, and engineering analysis; the project reviewer must verify the licensed edition used for approval.
ASHRAE Commissioning ResourcesCommissioning-process context for defining test methods, acceptance criteria, evidence, and owner requirements.
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.
