Modular Pumped Thermal Storage Units for Geographic Flexibility
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Solution Overview
Problem
Current energy storage systems face limitations in efficiency, reliability, and cost, particularly for large-scale applications, and lack geographical and resource flexibility, with existing alternatives like pumped hydroelectric and solar thermal systems having specific geographical and resource dependencies.
Innovation Solution
The development of pumped thermal energy storage systems that utilize a closed fluid cycle with a compressor, turbine, and heat storage units, allowing for efficient storage and retrieval of electrical and thermal energy through heat exchange processes, and can operate as both heat engines and heat pumps, enabling flexible energy conversion and storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If pumped hydroelectric storage systems are used to store electrical energy, then large scale energy storage is achieved, but geographical and resource constraints limit system deployment
Solution Approach 1:
The patent replaces the mechanical gravity-based pumped hydroelectric system with a thermodynamic system using compressors, turbines, and heat exchangers. The working fluid undergoes compression and expansion cycles to store and release energy, eliminating the need for geographical features like elevation differences and large water bodies.
Solution Approach 2:
The system changes the physical state and parameters of a working fluid (temperature, pressure, phase) to store and release energy. During charging, the compressor increases pressure and temperature of the working fluid; during discharge, the turbine expands the fluid to generate power, providing flexibility independent of geographical constraints.
2Temperature
If solar thermal systems are used to store thermal energy, then thermal energy storage is achieved, but resource dependency on solar availability limits system reliability
Solution Approach 1:
The thermodynamic system can operate in multiple modes: as a heat engine during discharge, as a heat pump during charging, and can accept various heat sources including but not limited to solar thermal energy. This multi-functionality ensures reliability by allowing the system to operate with different energy sources regardless of solar availability.
Solution Approach 2:
The system can store thermal energy internally through the phase change and temperature variation of the working fluid, and retrieve it when needed without continuous external input. The compressed and expanded states of the working fluid maintain thermal energy storage capability independently of ongoing solar input.
3Use of energy by moving object
If conventional energy storage systems are used, then energy storage function is provided, but roundtrip efficiency and cost-effectiveness are insufficient
Solution Approach 1:
The system utilizes phase transitions of the working fluid (liquid-vapor transitions) during compression and expansion processes. These phase changes occur at constant temperature and pressure, enabling efficient energy storage and retrieval with minimal losses, as the latent heat is effectively captured and released during the cycle.
Solution Approach 2:
The system employs periodic compression and expansion cycles of the working fluid to store and release energy. The regular alternation between charging (compression) and discharging (expansion) phases maintains optimal thermodynamic conditions, minimizing energy losses and maximizing roundtrip efficiency through repeated reversible processes.
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
These systems achieve high roundtrip efficiency and cost-effectiveness while being independent of geographical and resource constraints, capable of storing and releasing both electrical and thermal energy effectively.
Implementation Method 1
a compressor, a first heat storage unit, a turbine, and a second heat storage unit. The system further comprises an auxiliary tank for a working fluid
Implementation Method 2
Heat exchange (sensible energy transfer) between the working fluid of the system and the heat storage fluids can occur in counter-flow heat exchangers
Implementation Method 3
a compressor, a first heat storage unit, a turbine, and a second heat storage unit
Implementation Method 4
The system can operate as a heat engine by transferring heat from the hot side to the cold side, resulting in net mechanical work output
Implementation Method 5
The mechanical work inputs and/or outputs may be converted from/to electrical work using a motor/generator
Data Source
AI summary
An example method may comprise providing a composite pumped thermal system having a plurality of subunits, each configured for operation in a thermal storage mode and a power generation mode; operating the system in power output mode with a power output level at an intermediate output level between 0% and 100% of a maximum output level of the system; reducing the power output level to 0% of the maximum output level by reducing a power output of a first subunit operating in a power generation mode; and at 0% of the maximum output level, wherein a power input level of the system is also at 0% of a maximum input level of the system, increasing the power input level to an intermediate input level between 0% and 100% of the maximum input level by increasing a power input of a second subunit operating in a thermal storage mode.