A power-saving type liquefied-gas-fuel ship includes: a liquefied gas storage tank storing liquefied gas; an engine using the liquefied gas stored in the liquefied gas storage tank or boil-off gas generated by spontaneous vaporization of the liquefied gas as fuel; a fuel feeder supplying the liquefied gas as fuel for the engine; a compressor compressing the boil-off gas to a pressure required for the engine; a heat exchanger cooling the remaining boil-off gas not supplied to the engine among the boil-off gas compressed by the compressor; a refrigerant circulation line in which the refrigerant supplied to the heat exchanger circulates; a refrigerant compressor compressing the refrigerant discharged from the heat exchanger after heat exchange in the heat exchanger; and a cold heat recovery device recovering cold heat of the liquefied gas supplied as fuel for the engine to cool the refrigerant compressed by the refrigerant compressor.

Disclosed are a system and method for reliquefaction of boil-off gas of a ship and a system and method for treating off-gas of a reliquefaction apparatus. The boil-off gas reliquefaction system includes: a compressor compressing boil-off gas generated from liquefied gas stored in an on-board storage tank; a heat exchanger cooling the boil-off gas compressed in the compressor; a refrigerant circulation line in which a refrigerant supplied to the heat exchanger circulates; a temperature raising line extending from the storage tank to the compressor; and a heater provided to the temperature raising line, wherein the heater heats the boil-off gas to a suitable input temperature of the compressor.

A storage facility includes a tank for transporting and/or storing gas in a liquid state, the tank including at least one insulation layer, a gas-consuming device, and one device for suctioning the gas present in the insulation layer. The suction device includes a primary branch fluidly connected to the gas-consuming device, at least one secondary branch fluidly connected to the insulation layer of the tank and through which the gas from the insulation layer flows, and at least one suction member configured to suction the gas flowing through the secondary branch.