Hydro-Pneumatic Accumulator Racks with Multi-Pressure Charging
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Solution Overview
Problem
Hydro-pneumatic energy storage systems face limitations in energy density due to space constraints and the need for precharge pressure matching the operating pressure of hydraulic circuits, which restricts their efficiency and capacity.
Innovation Solution
A hydro-pneumatic energy storage system with a method of charging that compartmentalizes precharge volumes to different pressures, allowing for increased energy storage by pressurizing gas in multiple accumulators to varying precharge pressures, while maintaining compatibility with hydraulic circuit operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the system size is increased to store more energy, then the energy storage capacity increases, but the space required increases which is not feasible
Solution Approach 1:
The system divides the energy storage function across multiple accumulators (first accumulator with first gas volume, second accumulator with second gas volume) instead of using one large accumulator. This segmentation allows the system to achieve greater total energy storage capacity while maintaining a compact overall volume by distributing the storage function across separate pressure zones.
Solution Approach 2:
The invention adds a pressure dimension to the energy storage system by implementing accumulators at different precharge pressures (first precharge pressure and second precharge pressure). This multi-pressure approach enables the system to store more energy within the same volume by utilizing pressure as an additional degree of freedom, effectively transforming a single-pressure system into a multi-pressure system.
2Quantity of substance
If the precharge pressure is increased to store more energy, then the energy density increases, but the system must match the hydraulic circuit operating pressure which limits the pressure range
Solution Approach 1:
The system segments the pressure range by creating multiple accumulators with different precharge pressure levels. The first accumulator operates at a first precharge pressure while the second accumulator operates at a second precharge pressure (higher than the first). This segmentation allows each accumulator to be optimized for its specific pressure range while collectively providing a broader overall operating range that adapts to varying hydraulic circuit requirements.
Solution Approach 2:
The invention changes the precharge pressure parameter across different accumulators rather than using a uniform precharge pressure. By setting the second precharge pressure higher than the first precharge pressure, the system can dynamically select which accumulator to charge or discharge based on the required operating pressure, thereby increasing energy density while maintaining adaptability to different hydraulic circuit operating conditions.
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
This approach enhances energy density by allowing a larger pressure increase and extending the accessible pressure range, ensuring smooth transitions during charging and discharging, and maintaining system efficiency by matching precharge pressures with hydraulic circuit requirements.
Implementation Method 1
pressurizing the process gas contained in the first volume to a first hydro-static precharge pressure p01... pressurizing the gas in the first volume by discharging a non-compressible hydraulic fluid into the first vessel
Implementation Method 2
hydro-pneumatic energy storage system... energy may be stored in the system by discharging a quantity of a non-compressible hydraulic fluid into the variable space inside the vessel such that the process gas contained in the closed volume inside the vessel is compressed and pressurized
Implementation Method 3
pre-pressurizing the gas contained in the second volume to a second hydrostatic precharge pressure p02, the second precharge pressure being higher than the first precharge pressure: p02>p01
Implementation Method 4
compartmentalizes precharge volumes to different pressures, allowing for increased energy storage by pressurizing gas in multiple accumulators to varying precharge pressures
Implementation Method 5
The flow of hydraulic fluid generated by the expanding gas may then drive a hydraulic device such as a hydraulic motor or a hydraulic piston
Data Source
AI summary
A method of charging a hydro-pneumatic energy storage system is described. The system has a first hydro-pneumatic accumulator with a first hollow vessel. Disposed within the first hollow vessel is a first compressible volume containing a first amount of gas. The system has a second hydro-pneumatic accumulator with a second hollow vessel. Disposed within the second hollow vessel is a second compressible volume containing a second amount of gas. The gas contained in the first volume is pre-pressurized to a first hydrostatic pre-charge pressure and the gas contained in the second volume is pre-pressurized to a second hydrostatic pre-charge pressure. The second pre-charge pressure is higher than the first pre-charge pressure. In addition, the gas in the first volume is pressurized by discharging a non-compressible hydraulic fluid into the first vessel while keeping a quantity of non-compressible hydraulic fluid contained in the second vessel constant to keep the pressure of the gas contained in the second volume at the second pre-charge pressure.