A DIY Pulse Tube Cryocooler in the quest for homemade liquid nitrogen

What if you need liquid nitrogen, but don't want to just order it from a local supplier? In that case, you can build your own pulse-tube cryocooler, like [Hyperspace Pirate] is doing on YouTube. You can catch part 1 using a linear motor and part 2 using a reciprocating piston version also after the break. Although still a work in progress, the second version of the cryocooler succeeded in reducing the temperature down to -75°C.

The pulse tube cryocooler is one of many types of systems used to create a cooling effect. Commercial refrigerators and freezers tend to use Rankine cycle coolers due to their low cost and efficiency at (relatively) warmer temperatures. For cryogenic temperatures, Stirling engines are commonly used, although they also find some use in refrigeration. All three share common elements, but differ in effectiveness over a wider temperature range.

In this video series, the viewer is guided through the physics behind these coolers and the bottlenecks that prevent them from simply cooling to zero Kelvin. Despite the deceptive simplicity of pulse tube cryocoolers - with a single piston, regenerative mesh and a few tubes - getting them to work properly is an exercise in patience. We look forward to future videos in this series as it develops.