Follow the explanation
Back to the model ↑How the parts work together
Heat and expand
At the hot-space expansion pose, the displacer has shifted most gas toward the hot end. The power piston then moves outward. In an ideal Stirling cycle, external heat keeps the gas approximately at the hot temperature while it expands.
Cross the regenerator
The displacer moves gas toward the cold end through the regenerator. The regenerator is a heat store, not a fuel source: ideally it accepts heat during this transfer and returns it on the way back.
Cool and compress
With most gas at the cold end, the power piston moves inward. Ideal-cycle diagrams treat this as approximately isothermal compression; this animation only shows the sequence, not pressure or work.
Return to the hot end
The displacer sends gas back through the regenerator. Adjust the crank phase: the two links change timing together, making the reason for two separate moving parts visible.
The main parts
- Hot space
- The heated end of the cylinder. The orange field is a location cue, not a calculated temperature map.
- Cold space
- The cooled end of the cylinder. Cooling makes compression require less work in the ideal cycle.
- Displacer
- A loose piston that shifts gas between ends. It is intentionally shown with a clearance: it does not seal or extract work like the power piston.
- Regenerator
- A porous heat store placed in the transfer path. Gas passing through it gives up or takes back heat; the drawing does not calculate its effectiveness.
- Power piston
- The sealing piston that changes the total gas volume and drives the connecting rod in this schematic.
- Phased cranks
- Two crank pins hold the displacer and power-piston motions at the selected angular offset.