In one example embodiment, there is provided a flowmeter system. The flowmeter system includes a high temperature transferring part that collects external heat energy to transfer the heat energy; a low temperature transferring part that transfers heat energy of an intake pipe; a stirling engine that produces a power based on a temperature difference between the heat energy transferred from the high temperature transferring part and the heat energy transferred from the low temperature transferring part; and a flowmeter that is supplied with the power produced by the stirling engine to measure a flow rate of the intake pipe.