Various free-piston Stirling engine configurations were invented and developed in the 1960s. These machines required no mechanical linkages since the moving parts are either driven by internal gas pressure or a linear motor/alternator. Later developments included gas bearings where both the piston and displacer are supported on helium bearings, thus eliminating the need for any lubrication whatsoever.

Until the introduction of the Stirling free-piston engine ultra-low temperature (ULT) freezer technology saw little change or improvement over the last five decades.  And yet, compressor-based freezers demand large amounts of power to operate . . . as much as the average U.S. home! Now there is a more cost-effective and energy-efficient freezer alternative with Stirling Ultracold. Consider the cumulative savings of replacing multiple compressor-based ULTs with Stirling energy-efficient freezers . . .

Stirling Ultracold ultra-low freezers use significantly less energy to operate than the standard compressor-based system. Our models also reduce HVAC requirements because they reject less than one third the heat of typical compressor-based ULT systems. The reduced heat also means researchers will be more comfortable when working near the Stirling freezers.