How air conditioners are made

An air conditioner moves heat around a copper loop that is leak-tested and dried before any refrigerant goes in.

stations: 6
things upstream: 65
raw sources: 23
steps from the ground: 8

The short version

Copper tubes are bent into hairpins and threaded through stacks of thin aluminum fins to make the coils. The joints are brazed, leak-tested with pressurized gas, and dried. The coils join a compressor, fan and sheet-metal case, the loop is emptied of air, and a measured charge of refrigerant is added.

Bend the copper hairpins

Straight lengths of copper tube are bent into U-shaped hairpins. They will carry refrigerant through the coil.

Goes in
Copper
Stamp the aluminum fins

Thin aluminum sheet is stamped into fins with holes for the tubes. Hundreds of fins stack up so air can touch a huge surface.

Goes in
Aluminum
Lace tubes through fins

Hairpins are pushed through the stack of fins. The tubes are then expanded so they grip the fins tightly.
Braze and leak-test

Torches and filler metal join tube ends and headers. Gas under pressure then checks the coil for leaks before it is dried.

Goes in
Solder
Assemble the unit

The coils go into a painted sheet-metal case with a compressor, fan motors and controls.

Goes in
Sheet steel Electric motor
Evacuate and charge

A vacuum pump pulls moisture and air out of the sealed loop, and a charging machine adds the right amount of refrigerant.

Goes in
Refrigerant

End of the lineAir conditioner

Worth repeating

In 1820 Michael Faraday found that compressing and liquefying ammonia, then letting it evaporate, chilled the air around it.
Willis Carrier designed what is widely regarded as the first modern electrical air-conditioning system in 1902, for a Brooklyn printing plant that needed its paper to hold still.