Ton of refrigeration
A ton of refrigeration (commonly abbreviated as TR) is a unit of power used in some countries (especially in North America) to describe the heat-extraction capacity of refrigeration and air conditioning equipment. It is defined as the latent heat absorbed by melting a short ton of pure ice at 0°C (32°F) in 24 hours. It is equivalent to the consumption of one ton of ice per day and originated during the transition from stored natural ice to mechanical refrigeration.
A refrigeration ton is approximately equivalent to 12,000 BTU per hour or 3517 watts. Air-conditioning and refrigeration equipment capacity in the U.S. is often specified in "tons" (of refrigeration). Many manufacturers also specify capacity in BTU/h, especially when specifying the performance of smaller equipment.