Submerged multi-mode cryopump for refueling hydrogen, system having the same, and method of using the same

A system for refueling hydrogen, comprising:

• a cryotank configured to store a liquefied fuel therein, wherein the liquefied fuel is hydrogen;
• a pump configured to be disposed inside the cryotank and provide a stream of the liquefied fuel from the cryotank, the pump having a piston, an intake port, and an isolation valve configured to supply the liquefied fuel to the intake port, wherein the piston has a front side facing the intake port and a backside opposite to the front side;
• a first pipe fluidly connected to a vapor pump chamber configured to hold vapor of the liquefied fuel in the pump;
• a second pipe fluidly connected to a first liquid pump chamber configured to hold the liquefied fuel contacting a backside of the piston;
• a switching valve fluidly connected to the first pipe and the second pipe, and configured to flow the vapor of the liquefied fuel in the pump and the liquefied fuel contacting the backside of the piston to the intake port of the pump through a third pipe;
• at least one block valve fluidly connected to the first pipe, the second pipe, the cryotank, and the switching valve;
• and
• a controller connected with the cryotank, the at least one block valve, and the switching valve, and configured to actuate the at least one block valve, the switching valve, and/or the isolation valve so as to operate the system in one of three working modes including a pressure increase mode, a pressure maintaining mode, and a pressure decrease mode, based on the headspace pressure in the cryotank.