TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Fuel Cell System: The outlet pipe has an outlet port arranged near a heat source that vaporizes the atomized water, where the atomized water discharged from the outlet pipe is discharged toward an upstream side of the heat source in a flow direction of current directed toward the heat source. The fuel cell system further comprises a nozzle that is arranged to be movable relative to the venturi and discharges the water in the inlet pipe into the outlet pipe; a moving device that moves the nozzle between an operating position, in which an end portion of the nozzle is located near a cross-sectional centerline of the venturi, and a retracted position, in which the nozzle is protruded from an inner circumferential surface of the venturi by an amount less than that when in the operating position; and a control unit that controls the moving device; where the control unit moves the nozzle to the operating position when a drive device, which is driven by power from the fuel cell, is supplied with power that is greater than or equal to a predetermined value, and the control unit moves the nozzle to the retracted position when the drive device is supplied with power that is less than the predetermined level. The fuel cell system is installed in an industrial vehicle including a load handling device; the drive device includes a vehicle drive motor and a load handling drive device, which drives the load handling device; and the control unit moves the nozzle to the operating position when at least one of the vehicle drive motor and the load handling drive device is supplied with power that is greater than or equal to the predetermined value, and the control unit moves the nozzle to the retracted position when the vehicle drive motor and the load handling drive device are both supplied with power that is less than the predetermined level. The fuel cell system further comprises a valve arranged in the inlet pipe; where the control unit controls an open degree of the valve in accordance with an exhaust amount of the fuel cell to adjust an amount of the water discharged from the nozzle into the outlet pipe. The inlet pipe includes a first pipe member extending from the tank toward the outlet pipe; a second pipe member extending from the first pipe member into the outlet pipe and having a side wall portion provided with a water supply port; and a water deflection member extending from the second pipe member in a radial direction of the outlet pipe and arranged in the outlet pipe in or near the venturi; and water supplied to an outer circumferential surface of the second pipe member through the water supply port moves to an end portion of the water deflection member and is atomized at the end portion of the water deflection member by gas flowing in the outlet pipe. The water deflection member is arranged on a distal portion of the second pipe member to close the distal portion and extend in the radial direction entirely from a circumference of the distal portion. The gas-liquid separator is formed to mix exhaust from an anode side of the fuel cell with exhaust from a cathode side of the fuel cell, the outlet pipe being connected to an outlet port of the gas-liquid separator; and the first pipe member extends from the tank toward the outlet pipe in the gas-liquid separator or in contact with a wall surface of the gas-liquid separator. The first pipe member is held in the gas-liquid separator by a bracket, which is attached to the gas-liquid separator, at a position spaced apart by a predetermined distance from an inner wall surface of the gas-liquid separator. The second pipe member extends substantially parallel to the flow of gas in the outlet pipe and substantially along a cross- sectional center of the venturi in the outlet pipe. The inlet pipe has a distal portion located in the outlet pipe in or near the venturi inside, and a porous member that is capable of discharging water into the outlet pipe is arranged on the distal portion. The porous member is a metal sinter. The distal portion of the inlet pipe is located near an inner circumferential surface of the outlet pipe, and the porous member protrudes into the outlet pipe from the distal portion of the inlet pipe. The porous member includes an upstream region, which faces toward a flow of gas in the outlet pipe, and a downstream region opposite to the upstream region, and where a cover that covers the downstream region is arranged on the porous member. The fuel cell system further comprises an inlet nozzle arranged in the inlet pipe so as to protrude into the venturi, the inlet nozzle drawing the water contained in the tank into the venturi; an expansion chamber arranged downstream of the venturi in the outlet pipe to form water droplets from some of the atomized water, which has been drawn into and atomized by the venturi, and collect the water droplets; a return pipe that returns water collected in the expansion chamber to the venturi; and a tubular member arranged at an exit of the expansion chamber so as to protrude into the expansion chamber. A return nozzle protruding into the venturi is arranged on a distal end of the return pipe; and the return nozzle is arranged upstream of the inlet nozzle in the venturi. The outlet pipe includes a flow path formation block that forms part of the outlet pipe, the venturi, and the expansion chamber, the flow path formation block being formed from a resin material. An entire outer surface of a downstream portion of the tubular member is in contact with an entire inner surface of the exit of the expansion chamber. The fuel cell system is installed in an indoor industrial vehicle. The fuel cell system further comprises a hydrogen pipe that draws anode off-gas from the fuel cell into the gas-liquid separator; where the gas-liquid separator has a dilution function for diluting hydrogen, which is contained in the anode off-gas. The fuel cell system further comprises a hydrogen pipe that draws anode off-gas from the fuel cell into the gas-liquid separator; where the gas-liquid separator has a dilution function for diluting hydrogen, which is contained in the anode off-gas. A venturi is arranged in the inlet portion. The outlet pipe has an outlet port arranged near a heat source that vaporizes the atomized water. The atomized water discharged from the outlet pipe is discharged toward an upstream side of the heat source in a flow direction of current directed toward the heat source. The pressure regulation valve is a butterfly valve moved between a valve-open position, which increases a flow path cross- sectional area of the outlet pipe, and a valve-closed position, which decreases the flow path cross-sectional area of the outlet pipe; where the inlet portion is arranged in the outlet pipe at a position facing toward a distal portion of the butterfly valve arranged in the valve-closed position.