A method and system are provided for operating refueling station tube-trailers and compressors to reduce hydrogen refueling cost. A hydrogen refueling station includes a two-tier fuel supply of pressure vessels on a refueling station tube-trailer, with a first tier and a second tier of pressure vessels including at least one or more pressure vessels connected together. A separate control unit is coupled to the first tier and the second tier of pressure vessels with each of the control units coupled to a compressor. The compressor is coupled to a high pressure buffer storage by a separate control unit. In operation, pressure is monitored in the each tier. Hydrogen is consolidated selectively between the first tier of pressure vessel banks, the second tier pressure vessels, and the high pressure buffer. Based upon monitored pressures, one of the first tier of pressure vessels, the second tier pressure vessel banks, and the high pressure buffer is used to refuel vehicles.

A reciprocating piston cryogenic pump has been suspended from stroking when process fluid discharge temperature from a vaporizer dropped below a threshold to prevent freezing of a heat exchange fluid circulating through the vaporizer and damage to downstream components. Suspension of the pump results in a decrease of process fluid pressure downstream of the vaporizer, which is undesirable. In the present technique, a temperature is monitored correlating to process fluid temperature downstream of the vaporizer. The amount of process fluid discharged from the pump in each cycle is adjusted as a function of the temperature such that the average residence time of the process fluid in the vaporizer is increased as the discharge amount decreases, increasing process fluid discharge temperature. The average mass flow rate of the process fluid through the vaporizer is unchanged regardless of pump discharge amount such that process fluid pressure downstream of the vaporizer is maintained.

A drive system for a cryogenic pump is provided including a spool housing having a plurality of valves disposed therein about a pump axis and a tappet housing including a plurality of tappet bores, each tappet bore in communication with a respective one of the plurality of valves. A collection cavity collects hydraulic fluid from the tappet bores. A pump flange includes a fluid inlet and a fluid outlet. An inlet manifold directs hydraulic fluid received through the fluid inlet to each of the plurality of valves. An outlet manifold directs hydraulic fluid from each of the valves and the collection cavity to the fluid outlet.

A cryogen storage vessel at an installation is filled with liquid cryogen from a liquid cryogen storage tank that has a pressure lower than that of the vessel. After headspaces of the vessel and tank are placed in fluid communication with another via a gas transfer vessel and are pressure-balanced, a pump in a liquid transfer line connected between the tank and the vessel is operated to transfer amounts of liquid cryogen from the tank to the vessel via the liquid transfer line and pump as amounts of gaseous cryogen are transferred, through displacement by the pumped cryogenic liquid, from the vessel to the tank. Following filling, the tank is disconnected and then driven to another location to repeat the filling process with a second vessel that is at a different location.

A cryogen storage vessel at an installation is filled with liquid cryogen from a liquid cryogen storage tank that has a pressure lower than that of the vessel. After headspaces of the vessel and tank are placed in fluid communication with another via a gas transfer vessel and are pressure-balanced, a pump in a liquid transfer line connected between the tank and the vessel is operated to transfer amounts of liquid cryogen from the tank to the vessel via the liquid transfer line and pump as amounts of gaseous cryogen are transferred, through displacement by the pumped cryogenic liquid, from the vessel to the tank.

A liquid petroleum gas (LPG) fuel supply system for a vehicle having an internal combustion engine includes an LPG tank, a fuel pump housing, a fuel pump inside the fuel pump housing, a fuel supply line connected between the LPG tank and the fuel pump housing, and a vapor release port located on the fuel pump housing. The vapor release port is connected to the LPG tank by a vapor return line. The fuel pump housing fills with LPG from the LPG tank under the action of gravity. Vapor forms in the fuel pump housing, separates from the liquid, gathers toward the top of the fuel pump housing, and under the action of gravity, displaces through the vapor port, rises through the vapor return conduit, and is released into the LPG tank 19, balancing pressure and preventing vapor lock.

A heat exchanger generally employs a method for supplying liquid having critical pressure or higher or high pressure in order to suppress boiling. However, gas obtained by a evaporator behind the heat exchanger has relatively low pressure, and therefore supplying the liquid to the heat exchanger requires a system for converting an energy form of the obtained gas into kinetic energy or electrical energy, and increasing the pressure by a mechanical pump. Thus, the complicated system involving an efficiency loss is only solution, and it is difficult to achieve simplification of a system or reduction in the weight of a propellant supply device in a moving body, specifically, a flying object.

Systems and methods for reducing cavitation of a pump in a liquid transfer system including a pump and a liquid storage tank. More particularly, systems and methods for maintaining and adjusting Net Positive Suction Pressure (NPSP) are provided to the pump.

A drive system for a cryogenic pump is provided including a spool housing having a plurality of valves disposed therein about a pump axis and a tappet housing including a plurality of tappet bores, each tappet bore in communication with a respective one of the plurality of valves. A collection cavity collects hydraulic fluid from the tappet bores. A pump flange includes a fluid inlet and a fluid outlet. An inlet manifold directs hydraulic fluid received through the fluid inlet to each of the plurality of valves. An outlet manifold directs hydraulic fluid from each of the valves and the collection cavity to the fluid outlet.

A body structure includes an inlet port that receives fluid from a delivery device, a top-fill outlet port that connects to a top-fill line in communication with a cryogenic tank, a bottom-fill port that connects to a bottom-fill line in communication with a cryogenic tank and a slider tube cylinder. A cylinder housing is connected to the body structure and has a pressure comparison cylinder with an upper volume and a lower volume, with the latter in fluid communication with a cryogenic tank. A piston slides within the pressure comparison cylinder and a piston shaft is connected to the piston. A pressure regulator is in fluid communication with the upper volume of the pressure comparison cylinder and the slider tube cylinder. A slider tube is connected to the piston shaft and slides within the slider tube cylinder. The slider tube cylinder directs fluid to a top-fill line through the top-fill outlet port when a pressure in the lower volume exceeds a pressure setpoint and fluid to a bottom-fill line through the bottom-fill outlet port when the pressure in the lower volume is below a pressure setpoint. An over-pressure member is positioned in the upper volume of the pressure comparison cylinder. The piston contacts the over-pressure member as the piston slides upward in the pressure comparison cylinder.