Vortex Tube theory<\/strong>\u00a0is one of the more interesting accidental inventions of the 20th Century\u2026splitting a flow of air into two streams: one hot, and one cold.\u00a0\u00a0Georges Ranque<\/a>\u00a0happened upon the phenomenon in the 1930s. He patented it in 1933, but it wasn\u2019t commercially viable at the time. In the 1940s, it caught the interest of German physicist Rudolph Hilsch<\/a>, who \u201ctweaked\u201d Ranque\u2019s design and published a widely read paper on it in 1947. Over the next few decades, the use of compressed air became more prevalent in a wide range of industries, eventually becoming the \u201c4th utility\u201d<\/a> that it\u2019s known as today. With that increase in use came improvements in air compressor design & function \u2013 improvements that finally bestowed long-awaited commercial viability on the Vortex Tube<\/a>.<\/p>\n So, how does it work? Ranque\u2019s patent and Hilsch\u2019s paper both detail what it is and what it does, but to this day, nobody\u2019s been able to offer any 100% scientific proof as to HOW it does what it does. The commonly accepted explanation involves a proven scientific principle called conservation of angular momentum. That\u2019s a mouthful, so let\u2019s break it down:<\/p>\n Momentum<\/span><\/strong> is a physical property of matter, defined by its mass and velocity\u2026and it depends on both. Something with more mass will have more momentum than something with less mass, if their velocities are the same. And something moving at a higher velocity will have more momentum than something that\u2019s moving slower, as long as their masses are the same. Unless otherwise specified, \u201cmomentum\u201d is usually considered to be linear \u2013 the matter is moving in one direction.<\/p>\n Angular momentum is also defined by mass and velocity, but its value is also affected by rotational inertia, which is determined by the distribution of its mass around the center point of its rotation. If an object moving at a certain velocity is forced closer to its rotational center point, it has to speed up to maintain (or conserve) angular momentum. Physics really, really, (really) wants to make that happen, according to the laws of conservation of matter & energy. And physics ALWAYS obeys the law\u2026which forces us to as well.<\/p>\n Consider figure skaters doing those dizzying moves where they spin on the ice on one skate. If the skater spins with their arms straight out and then brings their arms in, close to their body, they begin to spin faster. The skater\u2019s mass doesn\u2019t change, but their mass distribution around the rotational center point does\u2026so physics gets its way by increasing the velocity. Therefore, energy (angular momentum, in this case) is conserved. It\u2019s impressive how easy some of them make it look:<\/p>\n \n![\"\"](\"https:\/\/i0.wp.com\/blog.exair.com\/wp-content\/uploads\/2025\/01\/vthand-1.jpg?resize=760%2C610&ssl=1\")