Complete Guide: Converting BTU to Refrigeration Tons
Converting BTU per hour to refrigeration tons is essential in HVAC design, air conditioning sizing, and cooling system calculations. This comprehensive guide explains the conversion process, formula, and practical applications of BTU to ton conversion.
Understanding the Conversion
BTU per hour (British Thermal Units per hour) measures the rate of heat transfer, while refrigeration tons measure cooling capacity. One refrigeration ton is defined as the amount of cooling needed to freeze one ton of water in 24 hours.
Conversion Formula
The conversion from BTU/hr to refrigeration tons uses this simple formula:
This conversion factor of 12,000 BTU/hr per ton is exact and universally used in the HVAC industry.
Why 12,000 BTU/hr per Ton?
The refrigeration ton is based on the cooling effect of melting ice:
- 1 ton of ice = 2,000 pounds
- Heat of fusion for ice = 144 BTU per pound
- Total heat to melt 1 ton of ice = 2,000 × 144 = 288,000 BTU
- Over 24 hours: 288,000 ÷ 24 = 12,000 BTU/hr
- Therefore: 1 refrigeration ton = 12,000 BTU/hr
HVAC Applications
- Air Conditioner Sizing: Determining appropriate AC unit capacity
- Chiller Systems: Commercial and industrial cooling calculations
- Heat Pump Rating: Cooling mode capacity specifications
- Load Calculations: Building cooling requirement analysis
- Energy Efficiency: Comparing different cooling systems
Common Cooling Capacities
- Window AC units: 5,000-24,000 BTU/hr (0.42-2 tons)
- Residential central AC: 18,000-60,000 BTU/hr (1.5-5 tons)
- Commercial rooftop units: 60,000-600,000 BTU/hr (5-50 tons)
- Industrial chillers: 1,200,000+ BTU/hr (100+ tons)
Practical Examples
- Small bedroom AC: 6,000 BTU/hr = 0.5 tons
- Living room AC: 12,000 BTU/hr = 1 ton
- Whole house system: 36,000 BTU/hr = 3 tons
- Small office building: 120,000 BTU/hr = 10 tons
- Large commercial building: 1,200,000 BTU/hr = 100 tons
System Sizing Considerations
When using BTU to ton conversion for HVAC sizing:
- Heat Load Calculation: Consider building size, insulation, occupancy
- Climate Factors: Local temperature and humidity conditions
- Efficiency Ratings: SEER, EER, and COP ratings
- Peak vs Average: Design for peak cooling loads
- Safety Margins: Typical 10-20% oversizing for comfort
Energy Efficiency Metrics
Understanding efficiency in relation to BTU and tons:
- EER: BTU/hr output per watt of electrical input
- SEER: Seasonal average efficiency rating
- COP: Coefficient of Performance (heat pumps)
- kW per Ton: Electrical power consumption per ton of cooling