Abstract: A rotatable micro-machine is comprised of a solvent reservoir, a porous evaporation region and a channel connecting the solvent reservoir to the evaporation region. The evaporation region may be constructed of capillary paths that enable a capillary action which pulls solvent from the channel so as to enable a flow of solvent from the reservoir to the evaporation region through the channel. A rotatable member has portions in communication with the channel so as to be rotated by the flow. In one embodiment, the rotatable member may be a component of a micro-turbine generator. A system may be comprised of the rotatable micro-machine in combination with at least one electrical circuit. The porous region may be positioned to receive heat from the circuit.