Liquid-Piston Gas Cooling for Isentropic Hydrogen Expansion
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Solution Overview
Problem
Current hydrogen refueling stations require additional chillers to cool hydrogen due to isenthalpic expansion at the proportional valve, increasing energy consumption and costs, and existing solutions are inefficient and costly.
Innovation Solution
A device utilizing a piston chamber with a liquid piston and damping system to achieve isentropic expansion, dynamically controlling pressure and removing heat, potentially replacing the need for a pressure ramp regulator and chiller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If isenthalpic expansion at proportional valve is used for pressure regulation, then pressure control is achieved, but significant heat is released causing gas temperature to exceed maximum permissible limits
Solution Approach 1:
The patent changes the thermodynamic parameters of the expansion process from isenthalpic (constant enthalpy) to isentropic (constant entropy) by using a piston-cylinder mechanism with controlled expansion. This parameter change allows pressure regulation while minimizing temperature increase, solving the contradiction between pressure control and temperature management.
Solution Approach 2:
The patent replaces the conventional proportional valve (pneumatically or magnetically actuated) with a mechanically controlled piston system. This mechanical substitution enables isentropic expansion through controlled piston movement, achieving pressure regulation without the significant heat release characteristic of valve-based isenthalpic expansion.
2Temperature
If additional chiller is used to cool the gas after expansion, then temperature is reduced to acceptable levels, but electrical energy consumption increases
Solution Approach 1:
The patent performs cooling action during the expansion process itself rather than as a subsequent separate step. The isentropic expansion mechanism inherently limits temperature rise, and the piston system performs preliminary cooling work during expansion, eliminating or reducing the need for additional post-expansion chilling and associated energy consumption.
Solution Approach 2:
The patent converts the harmful heat release during expansion into a beneficial controlled process. By using isentropic expansion with a piston system, the expansion work itself contributes to cooling the gas, transforming what would be a harmful thermal effect into a useful cooling mechanism that reduces or eliminates the need for additional energy-consuming chillers.
3Temperature
If compression chiller is used to remove heat during expansion, then cooling is achieved, but device complexity and installation costs increase
Solution Approach 1:
The patent merges the expansion mechanism and cooling function into a single integrated piston-cylinder system. The isentropic expansion process inherently performs the cooling function, eliminating the need for separate compression chillers and reducing overall device complexity while achieving the required temperature management.
Solution Approach 2:
The expansion system serves its own cooling needs through the isentropic expansion process. The piston mechanism automatically performs the cooling function during expansion without requiring external cooling equipment, making the system self-sufficient and reducing overall equipment requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Significantly reduces cooling capacity requirements by 50-100%, offering a cost-effective and durable solution with reduced energy consumption and environmental impact.
Implementation Method 1
The functioning of the device according to the invention for cooling a gas, preferably hydrogen, is based on the principle of so-called isentropic expansion, in which work is taken away from the gas in order to cool it down.
Implementation Method 2
means for removing heat from the piston chamber and/or damping system
Data Source
AI summary
A device for cooling a gas and a hydrogen filling station, comprising at least one device according to the invention, are described. The device comprises the following: a piston chamber (2); a liquid piston (3) arranged in the piston chamber (2); a supply line (1) associated with the first end (9) of the piston chamber (2) and having an inlet valve (b); a discharge line (10) associated with the first end (9) of the piston chamber (2) and having an outlet valve (b); a piston (4) associated with the second end of the piston chamber (2); a damping system associated with the piston (4); a control unit (8) that is operatively connected to the damping system and dynamically regulates the pressure to be applied to the piston (4); and means for dissipating heat from the piston chamber (2) and/or damping system.