Refrigeration performance
Refrigeration Capacity Calculator
Calculate a refrigerant-side heat-transfer rate from a documented mass flow and evaporator enthalpy difference.
Capacity inputs
Use values from the same refrigerant state-point method and operating condition.
How to use this calculator
- Select the unit system used by the source data.
- Enter refrigerant mass flow and the evaporator enthalpy difference from matching state points.
- Use the result to compare a measured refrigeration-side rate with the documented test condition.
Formula
In SI units, kW = mass flow (kg/s) × enthalpy difference (kJ/kg). The tool converts the result to BTU/h and nominal refrigeration tons for comparison only.
Variables
| Variable | Meaning | Unit |
|---|---|---|
| Mass flow | Refrigerant mass passing the selected evaporator boundary | lb/min or kg/s |
| Enthalpy difference | Evaporator outlet enthalpy minus inlet enthalpy from a documented property method | BTU/lb or kJ/kg |
| Capacity | Refrigerant-side heat-transfer rate at that boundary | BTU/h or kW thermal |
Example
At 10 lb/min and a 40 BTU/lb evaporator enthalpy difference, capacity is 60 × 10 × 40 = 24,000 BTU/h, or 7.03 kW thermal and 2 nominal refrigeration tons.
Interpret the result carefully
Capacity follows the selected boundary and state points. It is not compressor electrical input, a rating at every condition, or proof of correct charge. Do not mix enthalpy data from a different refrigerant, pressure basis, location, or operating condition.
Property data is not generated here
This tool deliberately does not infer saturation temperatures, pressures, or enthalpies for a refrigerant. Obtain those values from reliable refrigerant property data or manufacturer documentation, then keep the measurement points consistent.
Frequently asked questions
Can this calculator identify the refrigerant?
No. It accepts a documented enthalpy difference. Refrigerant identification and property selection must occur before using this calculation.
Is a refrigeration ton electrical power?
No. A refrigeration ton is a conventional thermal-capacity rate. Electrical input depends on equipment efficiency and operating conditions.
Can I use pressure readings directly?
Not by themselves. Pressure must be converted to a saturation temperature or refrigerant state using the correct refrigerant property data and measurement location.