Pumped Heat Energy Storage System Pressure Matching
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Solution Overview
Problem
Conventional pumped heat energy storage (PHES) systems suffer from operation inefficiencies due to differing pressure ratios in heat pump and heat engine cycles, leading to higher temperature differentials and reduced overall efficiency, as well as oversized heat rejection systems.
Innovation Solution
The proposed solution involves balancing or splitting the total heat rejection between the charging and discharging circuits of the PHES system by matching operating pressures, thereby achieving identical heat transfer characteristics and reducing the size of the heat rejection system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional PHES systems use separate heat pump and heat engine cycles with different pressure ratios, then the system can store and retrieve thermal energy, but the temperature differentials increase and overall efficiency decreases
Solution Approach 1:
The patent applies parameter changes by unifying the pressure ratio between the heat pump cycle and heat engine cycle. By adjusting the pressure ratio parameter to be identical in both cycles, the system minimizes temperature differentials during heat transfer, thereby reducing energy losses and improving overall efficiency.
2Productivity
If the heat rejection system is sized for maximum capacity, then all thermal energy can be rejected, but the system becomes oversized and less efficient
Solution Approach 1:
The patent applies dynamics by making the heat rejection system size adaptable to actual operational requirements. The system dynamically adjusts the heat rejection capacity based on the actual thermal energy storage and retrieval needs, rather than being fixed at maximum capacity, thereby avoiding oversizing and improving efficiency.
3Loss of energy
If the pressure ratios in heat pump and heat engine cycles are matched, then temperature differentials are minimized, but the system design becomes more constrained
Solution Approach 1:
The patent applies universality by designing a unified pressure ratio that serves both the heat pump cycle and heat engine cycle. This universal pressure ratio parameter simplifies the system design by eliminating the need for separate pressure ratio optimization for each cycle, thereby reducing design complexity while minimizing energy losses.
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 the overall efficiency of the PHES system by minimizing temperature differentials and allowing for a potentially smaller heat rejection system, while also enabling the system to provide ancillary services by adjusting the size based on operational strategies.
Implementation Method 1
The first compressor may be configured to compress a first working fluid and generate thermal energy
Implementation Method 2
The first turbine may be fluidly coupled with the plurality of thermal storage vessels and configured to extract the thermal energy stored in the plurality of thermal storage vessels and convert the thermal energy to mechanical energy via an expansion of a second working fluid
Implementation Method 3
The first heat exchanger may be configured to receive the first working fluid from a first thermal storage vessel of the plurality of thermal storage vessels and to remove thermal energy from the first working fluid and the first closed loop
Implementation Method 4
The first closed loop may be configured to circulate a first working fluid
Data Source
AI summary
A pumped heat energy storage (PHES) system (100) including a charging circuit and a discharging circuit effective to balance or split a total heat rejection of the PHES system between the charging circuit and the discharging circuit. The charging circuit may include thermal storage vessels (102, 104) to store thermal energy generated from a first compressor (110). A first heat rejection system (128) is fluidly coupled with the thermal storage vessels to remove thermal energy from the charging circuit. The discharging circuit may include a first turbine (146) fluidly coupled with the thermal storage vessels to extract thermal energy stored in the thermal storage vessels and convert the thermal energy to mechanical energy via an expansion of a second working fluid. A second heat rejection system (156) is fluidly coupled with the thermal storage vessels and the first turbine to remove thermal energy from the discharging circuit.