Alkaline Lye Cycle for High-Density Energy Storage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current energy storage technologies, such as fossil and nuclear fuel storage methods, are inadequate for efficiently managing the intermittent nature of solar-regenerative energy sources like wind and photovoltaic power, leading to economic losses and grid overload issues due to low storage work and high energy losses in conversion processes.
Innovation Solution
A method and device utilizing a lye cycle process with metal hydroxides or metal salts, specifically sodium hydroxide solutions, for energy storage through reversible desorption and absorption of water vapor, coupled with electrical energy for compression and heat management, allowing for high-density energy storage independent of location.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If solar-regenerative energy is converted into chemical energy carriers like hydrocarbons, then energy storage capacity is improved, but overall energy recovery efficiency deteriorates to 25-35% due to multiple conversion steps
Solution Approach 1:
The invention extracts and utilizes the heat of absorption directly during the energy storage process, separating this thermal energy component from the chemical conversion process. By taking out the thermal energy that would otherwise be lost during chemical carrier synthesis and storage, the system recovers additional energy without requiring complete chemical conversion cycles, thus improving overall efficiency while maintaining storage capacity.
Solution Approach 2:
The lye cycle process enables continuous operation where the lye solution cyclically absorbs and releases water vapor while continuously transferring thermal energy. The heat of absorption is continuously utilized to drive the desorption process in subsequent cycles, creating a continuous useful action that eliminates idle periods and maximizes energy recovery efficiency throughout the storage system operation.
2Loss of energy
If heat pump compressors and expansion machines are used for energy storage, then energy recovery is improved to approx. 50%, but device complexity and cost increase
Solution Approach 1:
The lye solution acts as an intermediary substance that mediates between thermal energy storage and mechanical work production. Instead of directly converting thermal energy to mechanical work complex turbomachines, the lye solution absorbs and releases water vapor in a controlled manner, using this mass transfer process to drive simpler expansion mechanisms while maintaining high energy recovery rates.
Solution Approach 2:
The invention replaces complex mechanical compression and expansion systems with a chemical-absorption-based system. The lye's natural absorption and desorption of water vapor creates pressure differentials and thermal effects that can drive expansion machines more simply than traditional heat pump compressors, reducing mechanical complexity while maintaining energy recovery efficiency.
3Quantity of substance
If pure hydrogen is stored for energy recovery, then energy storage density is improved, but infrastructure requirements and recovery degree deteriorate due to new infrastructure needs
Solution Approach 1:
The lye solution serves multiple functions simultaneously: it acts as an energy storage medium, a thermal energy carrier, and a mass transfer agent. This multi-functionality eliminates the need for separate hydrogen storage tanks, handling systems, and combustion infrastructure, as the lye cycle integrates storage and energy recovery in a single system that can be implemented with existing industrial infrastructure.
Solution Approach 2:
The system changes the physical and chemical parameters of the storage medium from gaseous hydrogen to aqueous lye solution. This parameter change transforms the storage requirements from high-pressure gas containment to liquid-phase chemical absorption, utilizing existing chemical processing infrastructure rather than requiring new hydrogen-specific infrastructure, thereby reducing overall system complexity.
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 achieves high energy density storage comparable to water-pump storage plants, with improved energy recovery efficiency and location-independent operation, suitable for both renewable energy qualification and conventional energy overcapacity management.
Implementation Method 1
by desorption and absorption of water vapor
Implementation Method 2
by desorption and absorption of water vapor
Implementation Method 3
the vapor from desorption is compressed
Implementation Method 4
by using the absorption heat for steam generation, z. B. via a hot water generation for a flash evaporation
Data Source
Figure 1
AI summary
The invention relates to a method and an apparatus for storing energy in alkaline solution for the purpose of qualifying regenerative energy, in particular from wind turbines and photovoltaic systems, for demand-based supply to consumers and/or for storing temporary excess capacities from conventional energy management by absorption and desorption of steam in or from alkaline solutions, for example sodium hydroxide solution, wherein the electrical energy is coupled in by electric drives for compressing (1.10) the steam from the desorption and the recovery of the coupled-in energy is implemented by the use of the heat from absorption for heating and flash distillation (2.3) and technical work-perfoming expansion (7, 8) of the flash steam to the pressure level of the absorption. The advantage of the invention consists in the location-independent storage of energy with a high energy density, in comparison with the prior art, up to a working capacity which has until now only been achieved by pumped-storage hydroelectricity plants.