Coolant penetrating cold-end pressure vessel

In a pressurized close-cycle machine having a cold-end pressure vessel and of the type having a piston undergoing reciprocating linear motion within a cylinder containing a working fluid heated by conduction through a heater head by heat from an external thermal source, the improvement comprising:

• a heat exchanger for cooling the working fluid, the heat exchanger disposed within the cold-end pressure vessel wherein the cold-end pressure vessel contains a charge fluid, further including a continuous section of coolant tubing disposed within the cold-end pressure vessel to cool the charge fluid, wherein a section of the coolant tube is contained within a cooler for directing a flow of working gas across the coolant tube, further including a fan positioned to re-circulate and cool the charge fluid.

In a pressurized close-cycle machine having a hermetically sealed cold-end pressure vessel and of the type having a piston undergoing reciprocating linear motion within a cylinder containing a working fluid heated by conduction through a heater head by heat from an external thermal source, the improvement comprising:

• a heat exchanger for cooling the working fluid, the heat exchanger disposed within the cold-end pressure vessel wherein the cold-end pressure vessel contains a charge fluid, further including a continuous section of coolant tubing disposed within the cold-end pressure vessel to cool the charge fluid, wherein the section of coolant tube disposed within the cold-end pressure vessel includes extended heat transfer surfaces on the exterior of the coolant tube, and wherein a section of the coolant tube is contained within a cooler for directing a flow of working gas across the coolant tube.