What is ton of refrigeration?

A ton of refrigeration is a power unit measuring the heat removal capacity of cooling systems, equal to 12,000 BTU per hour. It is the standard capacity rating for commercial and industrial air conditioning units in the United States.

Real-world uses

The ton of refrigeration (TR) is used for rating commercial and industrial cooling systems, chillers, and large-scale HVAC equipment. A small commercial building might need a 20–100 TR chiller. Data centres measure cooling capacity in TR. One TR = 12,000 BTU/h = approximately 3.517 kW.

History

The ton of refrigeration originated in the 19th century ice trade, when mechanical refrigeration systems were judged by their ability to replace ice delivery. One ton was defined as the cooling equivalent of melting one ton of ice per day. As mechanical refrigeration displaced natural ice by the early 20th century, TR became a standard industrial cooling unit.

Common mistakes

Confusing refrigeration tons with metric tons of mass—they are completely unrelated. Also, the "ton" in TR originated from the cooling power needed to melt one short ton (2,000 lb) of ice in 24 hours, not from any mass being cooled.

What is milliwatt?

A milliwatt is a unit of power equal to one thousandth of a watt. It is used in low-power electronics, wireless communication systems, laser specifications, and medical device power ratings.

Real-world uses

Milliwatts measure the power of laser pointers (Class 1: <1 mW; Class 3B: up to 500 mW), Bluetooth radios (typically 1–100 mW), Wi-Fi transmitters, and fibre optic signals. They are used in optical communications, consumer electronics, and medical laser specifications.

History

Milliwatts became relevant as the miniaturisation era brought small electrical and optical devices into widespread use from the mid-20th century. Consumer electronics, telecommunications, and biomedical equipment all required power specifications at this sub-watt scale.

Common mistakes

Confusing milliwatts (mW) with microwatts (µW)—1 mW = 1,000 µW. Also, assuming all laser pointers operate at the same power level; safety regulations classify lasers by output power in mW, and even small increases can be hazardous to the eyes.

When is this conversion used?

Converting between ton of refrigeration and milliwatt is common when working across metric and imperial systems, such as international trade, travel between countries with different measurement standards, or following instructions from a different region.

Worked examples

1 ton of refrigeration = 3,516,852.84 milliwatt

1 milliwatt = 0.001 watt

How to convert ton of refrigeration to milliwatt

To convert ton of refrigeration to milliwatt, multiply the value by 3,516,852.84.

To convert milliwatt back to ton of refrigeration, multiply by 2.843451e-07.

Measurement standards

The watt is the SI derived unit of power, defined as one joule per second (kg·m²/s³). Horsepower remains in widespread informal use, particularly in the automotive industry, but has no single universal definition across regions.

Did you know?

The human body at rest produces about 80 watts of power — roughly enough to keep an incandescent light bulb glowing. During intense exercise, a trained cyclist can sustain over 400 watts, and elite sprinters briefly exceed 2,000 watts.

Quick reference: ton of refrigeration to milliwatt

ton of refrigerationmilliwatt
0.1351,685.284
0.51,758,426.42
13,516,852.84
27,033,705.68
517,584,264.2
1035,168,528.4
2587,921,321
50175,842,642
100351,685,284
250879,213,210
5001.758426e+09
1,0003.516853e+09

Common values

ton of refrigerationmilliwatt
LED light bulb0.00284345 ton of refrigeration10,000 milliwatt
Desktop computer0.08530354 ton of refrigeration300,000 milliwatt
Microwave oven0.28434514 ton of refrigeration1,000,000 milliwatt
Small car engine21.32588522 ton of refrigeration75,000,000 milliwatt
Wind turbine (large)853.03540878 ton of refrigeration3.000000e+09 milliwatt