Horsepower to Tons Of Refrigeration (hp to TR)
1 horsepower equals 0.2120361315 tons of refrigeration (rounded).
How to convert horsepower to tons of refrigeration
To convert horsepower to tons of refrigeration, multiply the number of horsepower by 0.2120361315. The factor is rounded to 10 significant digits. To go the other way, multiply tons of refrigeration by 4.716177347 (rounded).
tons of refrigeration = horsepower × 0.2120361315
Example: 10 horsepower = 2.120361315 tons of refrigeration.
Several different horsepower units exist. This site lists mechanical (745.7 W), metric (735.5 W) and electrical (746 W) horsepower separately.
About these units
Horsepower (hp)
The mechanical horsepower: 550 foot-pounds per second, about 745.7 watts. James Watt coined it to compare steam engines with draft horses.
Horsepower was a sales pitch before it was a unit. Late in the 18th century the Scottish engineer James Watt adopted the term to compare the output of steam engines with the draft horses they replaced. His 1782 experiments found that a brewery horse could produce 32,400 foot-pounds-force per minute, and in 1783 he and Matthew Boulton standardized the figure at 33,000 foot-pounds-force per minute. Customers could then be told how many horses an engine would replace.
That figure works out to 550 foot-pounds-force per second, or about 745.7 watts: the power needed to lift 550 pounds by one foot in one second. Several cousins exist, including metric horsepower and electrical horsepower, defined as exactly 746 W. Car ratings added more confusion. Early British taxable horsepower was a formula based on bore and cylinder count, not measured output, and American ratings before 1972 used SAE gross brake horsepower, measured without accessories. In the European Union, horsepower may be used only as a supplementary unit under Directive 80/181/EEC, in force from 1 January 2010.
1 horsepower = 745.6998716 watts (approximately).
Sources: Wikipedia: Horsepower; Wikipedia: Metric horsepower
Ton Of Refrigeration (TR)
12,000 BTU per hour, about 3.517 kW: the cooling power of melting one short ton of ice in a day. Air-conditioner capacity is quoted in tons.
Cooling capacity was first sold in the age of ice. The ton of refrigeration was the rate at which a machine could freeze, or an ice block could melt, one short ton of pure ice at 0 degrees Celsius in 24 hours. It grew up in the 1880s as mechanical refrigeration replaced natural ice, and Thomas Shipley of the York Manufacturing Company helped make it an industry standard in 1903.
The modern definition drops the ice and fixes the rate at 12,000 International Table British thermal units per hour, which is 3.516853 kilowatts, or about 3,026 kilocalories per hour. NIST gives the same figure as 3.516853 x 10^3 watts and does not mark it as exact. The unit survives mainly in North America, where air-conditioning and chiller capacity is quoted in tons, and a three-ton system therefore removes about 10.5 kilowatts of heat.
1 ton of refrigeration = 3,516.852842 watts (approximately).
Sources: Wikipedia: Ton of refrigeration; NIST SP 811, Appendix B.8
Related conversions
- Tons of refrigeration to horsepower (reverse)
- Horsepower to watts
- Horsepower to kilowatts
- Horsepower to megawatts
- Horsepower to gigawatts
- Horsepower to metric horsepower
- Horsepower to BTU per hour
- Horsepower to milliwatts
- Horsepower to electrical horsepower
- Horsepower to foot-pounds per second
- Horsepower to kilocalories per hour
- Horsepower to calories per second
- Horsepower to ergs per second
- Watts to tons of refrigeration
- Kilowatts to tons of refrigeration
See all power units.