The invention relates to a power drive device for liquid
heat engine cycling. The device consists of a
heat supply device, a pipeline, a heat-exchange device, a cooling device and a
piston device, wherein the
piston device consists of a liquid inlet, a liquid outlet, a cylinder, a
piston and a piston
coupling shaft; a liquid inlet of the cylinder is connected with a heating
pipe in the
heat supply device; a heating pressure-stabilizing storage device is connected between a liquid inlet
pipe of the piston device and the heating
pipe; the heating pipe is arranged inside the
heat supply device; the liquid outlet of the cylinder is connected with the cooling device through a cooling pipeline; the
cooling pipe between the liquid outlet of the cylinder and the cooling device is also communicated with a cooling pressure-stabilizing storage device; the liquid outlet of the cooling device is provided with a
supercharge pump; and the output end of the
supercharge pump is connected with the input end of the heating pipe in the heat supply device. The device can adopt
solar energy, geothermy and residual heat of an internal-
combustion engine, even residual heat discharged by cooling equipment and the like, does not
discharge 'the three wastes', and liquid in the pipeline can be recycled in a
system. The device can make
waste heat reutilized with high efficiency, thereby facilitating
energy conservation.