Refrigeration reference
Refrigeration Units and Measurement Reference
Keep capacity rates, state properties, and matched temperature differences separate when reviewing refrigeration calculations.
Capacity conversion table
| Thermal capacity | BTU/h | kW thermal | Refrigeration tons |
|---|---|---|---|
| 1 ton | 12,000 | 3.516853 | 1 |
| 1 kW thermal | 3,412.142 | 1 | 0.284345 |
| 1 BTU/h | 1 | 0.000293071 | 0.0000833333 |
Measurement and property units
| Quantity | US customary | SI | Use |
|---|---|---|---|
| Refrigerant mass flow | lb/min | kg/s | Capacity calculation boundary |
| Specific enthalpy | BTU/lb | kJ/kg | Refrigerating effect between state points |
| Capacity | BTU/h | kW thermal | Heat-transfer rate |
| Temperature difference | °F difference | K or °C difference | Superheat or subcooling calculation |
How to use the table
For capacity, retain a matched mass-flow and enthalpy-difference basis. For superheat or subcooling, retain a matched refrigerant, pressure-derived saturation temperature, and physical measurement location. A unit conversion cannot correct a mismatched state point.
Example
10 lb/min × 40 BTU/lb × 60 = 24,000 BTU/h, which is 2 refrigeration tons. Separately, a 10°F temperature difference is 5.56 K; that difference may represent superheat or subcooling only after its boundary is identified.
Limits
These are unit relationships, not refrigerant property tables or service targets. Use the correct refrigerant property data, manufacturer procedure, and applicable safety requirements for an actual system.
Related calculators
- Refrigeration Capacity Calculator
- Refrigerant Superheat Calculator
- Refrigerant Subcooling Calculator
- BTU Calculator
Sources and scope
Values shown are thermal-unit conversions. They do not establish equipment capacity at a given operating condition.