The Ton of Refrigeration (TR) is the standard unit used worldwide to measure the capacity of industrial refrigeration and air conditioning systems. The term has historical origins: it represents the amount of heat required to melt one American ton (907 kg) of ice at 0°C over a 24-hour period.
Important Conversions
| Unit | Equivalence |
|---|---|
| 1 TR | 12,000 BTU/h |
| 1 TR | 3.517 kW |
| 1 TR | 3,024 kcal/h |
| 1 TR | 4.72 HP (refrigeration horsepower) |
How to Calculate Capacity in TR
To size a chiller, you need to know the thermal load of the process. The basic formula is:
TR = (Flow Rate × ΔT × 4.186) ÷ 12.66
- Where:
- Flow rate in m³/h
- ΔT (temperature difference) in °C
- 4.186 is the specific heat of water
- 12.66 is the conversion factor to TR
Practical Applications
In industry, TR capacity is fundamental for:
- Chiller sizing: Equipment is specified by TR capacity
- HVAC projects: Calculating thermal load of environments
- Industrial processes: Determining cooling needs for machines
- Equipment comparison: Standardization facilitates technical analysis
Practical Example
A plastics industry with 5 injection machines, each generating 50,000 kcal/h of heat, would need:
- Total load: 5 × 50,000 = 250,000 kcal/h
- Conversion: 250,000 ÷ 3,024 = 82.7 TR
- Recommendation: 100 TR chiller (with 20% safety margin)