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 microwatt?

A microwatt is a unit of power equal to one millionth of a watt. It is used in ultra-low-power electronics, energy harvesting systems, biosensors, and precision scientific instrumentation.

Real-world uses

Microwatts measure the power of radio frequency (RF) signals received by antennas, ultra-low-power IoT sensors, cardiac pacemaker power consumption, and energy-harvesting devices. Satellite receivers may work with signals in the nanowatt to microwatt range. Wearable health monitors often operate at a few microwatts.

History

Microwatts became a meaningful engineering unit as semiconductor miniaturisation through the 1970s–2000s enabled ultra-low-power circuit design. The proliferation of wireless sensors, implantable medical devices, and battery-free energy harvesting systems in the early 21st century made µW-level power budgeting essential.

Common mistakes

Confusing microwatts (µW) with milliwatts (mW)—a difference of 1,000×. In RF engineering, power is often expressed in dBm (decibels relative to 1 mW), which requires knowing that 0 dBm = 1 mW = 1,000 µW, and negative dBm values correspond to sub-milliwatt levels.

When is this conversion used?

Converting between ton of refrigeration and microwatt 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 = 3.516853e+09 microwatt

1 microwatt = 0.000001 watt

How to convert ton of refrigeration to microwatt

To convert ton of refrigeration to microwatt, multiply the value by 3.516853e+09.

To convert microwatt back to ton of refrigeration, multiply by 2.843451e-10.

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 microwatt

ton of refrigerationmicrowatt
0.1351,685,284.00000006
0.51.758426e+09
13.516853e+09
27.033706e+09
51.758426e+10
103.516853e+10
258.792132e+10
501.758426e+11
1003.516853e+11
2508.792132e+11
5001.758426e+12
1,0003.516853e+12

Common values

ton of refrigerationmicrowatt
LED light bulb0.00284345 ton of refrigeration10,000,000 microwatt
Desktop computer0.08530354 ton of refrigeration300,000,000 microwatt
Microwave oven0.28434514 ton of refrigeration1.000000e+09 microwatt
Small car engine21.32588522 ton of refrigeration7.500000e+10 microwatt
Wind turbine (large)853.03540878 ton of refrigeration3.000000e+12 microwatt