Double acting alpha Stirling refrigerator

A double acting alpha Stirling refrigerator, comprising:

• at least one piston cylinder and at least one piston, wherein,
• the at least one piston is provided in the at least one piston cylinder, upper and lower ends of the at least one piston cylinder are closed, a cylinder air vent is provided at each closed position of the upper and lower ends of the at least one piston cylinder, the at least one piston is in a clearance fit with an inner wall of the at least one piston cylinder, and a closed cavity is formed inside the at least one piston;
• a pressure relief pipe is provided in the closed cavity of the at least one piston, and through holes corresponding to outlets of the pressure relief pipe are provided in upper and lower surfaces of the at least one piston, and middle parts of side walls of the at least one piston, respectively;
• the outlets of the pressure relief pipe are respectively provided in the through holes and matched to the through holes in size, so that an interior of the pressure relief pipe is connected to an inner cavity of the at least one piston cylinder outside the at least one piston;
• air outlets for connecting the closed cavity of the at least one piston to the inner cavity of the at least one piston cylinder are provided on the side walls of the at least one piston;
• and
• a traction frame configured to move relative to the at least one piston cylinder is provided outside the at least one piston cylinder, and a movement of the at least one piston is controlled by a movement of the traction frame, wherein
• a first one-way air outlet valve is provided on an upper part of the pressure relief pipe corresponding to the upper surface of the at least one piston, a second one-way air outlet valve is provided on a lower part of the pressure relief pipe corresponding to the lower surface of the at least one piston, so that the air only flows along a middle part of the pressure relief pipe toward upper and lower end faces of the at least one piston and flows into the inner cavity of the at least one piston cylinder;
• a first one-way air intake valve is provided on a side wall of the pressure relief pipe outside the first one-way air outlet valve or on the upper end face of the at least one piston, a second one-way air intake valve is provided on a side wall of the pressure relief pipe outside the second one-way air outlet valve or on the lower end face of the at least one piston so that the inner cavity of the at least one piston cylinder is connected to the interior of the closed cavity of the at least one piston;
• the one-way air intake valves allow gas to enter the closed cavity of the at least one piston only from the inner cavity of the at least one piston cylinder.