Stirling Cooler Stirling engine 12v DC power source FPSC Mechanical refrigerant free refrigeration
Stirling Engine running in reverse creates a cooling effect.
The Free Piston Stirling Cooler (FPSC) is an elegant, completely sealed heat transfer system that has only two moving parts (a piston and a displacer), and which can use helium as the working fluid without concern about seal leakage. The piston is typically driven by an oscillating magnetic field that is the source of the power needed to drive the refrigeration cycle. The magnetic drive allows the piston to be driven without requiring any seals, gaskets, O-rings, or other compromises to the hermetically sealed system. Claimed advantages for the system include environmental friendliness, cooling capacity, light weight, compact size, precise controllability, and high efficiency.
The FPSC was invented in 1964 by William Beale, a professor of Mechanical Engineering at Ohio University in Athens, Ohio. He founded and continues to be associated with Sunpower Inc., which specializes primarily in researching and developing FPSC systems for a wide variety of military, aerospace, industrial, and commercial applications. Sunpower also makes cryocoolers and special pulse tube coolers capable of reaching below 40°K (around --390°F, or --230°C). A FPSC cooler made by Sunpower was used by NASA to cool instrumentation in satellites.
Since 2002. another leading supplier of FPSC technology has been the Twinbird Company in Japan, which also markets a broad line of household appliances. Both Sunpower and Twinbird appear to work in collaboration with Global Cooling NV, which is located in the Netherlands, but has a research center in Athens, Ohio.
For several years starting around 2004, the Coleman Company sold a version of the Twinbird "SC-C925 Portable Freezer Cooler 25L" under its own brand name, but it has since discontinued offering the product, in spite of favorable customer reviews on Amazon. The portable cooler can be operated more than a day, maintaining sub-freezing temperatures while powered only by an automotive battery. This cooler is still being manufactured and distributed worldwide, with Global Cooling now coordinating distribution to North America and Europe. Other variants offered by Twinbird include a portable deep freezer (to --80°C), collapsible coolers, and a special model for transporting blood and vaccine.
In addition to the technical information available on the websites referenced above, a step-by-step photographic teardown of the Coleman (Twinbird) FPSC cooler is viewable online.