Method for improving gas bearing function at low thermal cooling power

A method for increasing working gas flow rate through gas bearings of a free piston, gamma configured Stirling heat pump in order to avoid a failure of the gas bearings, the Stirling heat pump being thermally connected to a storage chamber of a cooler, the Stirling heat pump having a displacer and having pistons driven in reciprocation at an operating frequency by linear electric motors, the cooler also having a temperature control that maintains a steady state storage chamber temperature by sensing storage chamber temperature and increasing piston amplitude at temperatures above the steady state storage chamber temperature and decreasing piston amplitude at temperatures below the steady state storage chamber temperature, the method comprising:

• (a) driving the pistons with the linear electric motors, that are driven by a variable frequency, AC power source;
• (b) sensing the pistons' amplitude of reciprocation;
• and
• (c) if the sensed piston amplitude is less than a selected piston activation amplitude, increasing the frequency of the AC power source to increase the Stirling heat pump's operating frequency;
• wherein the increase in the operating frequency reduces the Stirling heat pump's thermal cooling power causing the temperature control to increase the Stirling heat pump's thermal cooling power by increasing piston amplitude and thereby increasing working gas pressure amplitude to increase working gas flow rate through the gas bearings.