List of the main devices :
- Heat exchangers (*2)
- Joule thompson valve (evaporator)
All these devices are not subject to particular intellectual property and very well known in the industry except for the stirling.
The Stirling was develloped and well working in the early 60's but abandonned for industrial use during few decades. It comes back now with the devellopement of renewable energy but most od avaliable machine have a low power (few kW).
Example of seller on market : http://sunpowerinc.com/