Thermal Energy Storage And Method For Controlling A Thermal Energy Storage
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Solution Overview
Problem
Existing thermal energy storage systems face inefficiencies due to the need for constant supply of heated water during charging and discharging, leading to undesirable variations in thermal gradients and prolonged discharge times, especially when intermittent operation is required.
Innovation Solution
The system employs a network of primary and secondary boreholes with controllable valves and pumps to allow selective charging and discharging of fracture planes, enabling flexible operation and efficient heat transfer by directing fluid flow through specific sectors of the storage volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the entire thermal energy storage is charged, then the storage capacity is maximized, but the time period required before the storage can be discharged with a relatively high temperature difference becomes excessive
Solution Approach 1:
The thermal energy storage system is divided into multiple independently controllable fracture planes, each accessible through separate boreholes. This segmentation allows selective charging and discharging of individual fracture planes, enabling the system to provide heat quickly from a subset of planes rather than waiting for entire storage volume to reach optimal temperature difference.
Solution Approach 2:
Instead of charging the entire storage volume uniformly, the system applies partial action by targeting specific fracture planes for charging based on current thermal demands. This allows the system to maintain sufficient storage capacity while reducing the time required to achieve discharge conditions with high temperature difference.
2Device complexity
If the charging and discharging is performed for the entire volume at once, then the system structure is simple, but intermittent operation causes undesirable variations in thermal gradient through the fracture planes
Solution Approach 1:
The system segments the thermal storage into multiple fracture planes that can be independently controlled. This segmentation enables selective operation of individual planes, maintaining stable thermal gradients by avoiding intermittent start-stop operations across the entire system and allowing continuous or staggered operation of subsets of fracture planes.
Solution Approach 2:
The system introduces dynamic control capabilities through individual borehole and fracture plane control, allowing the thermal storage system to adapt its operation to varying thermal demands. This dynamic control maintains more stable thermal gradients by adjusting which fracture planes are active at any given time, rather than forcing uniform intermittent operation across all planes.
3Quantity of substance
If a constant supply of heated water is maintained over an extended period, then the thermal energy storage capacity is maximized, but the flow rate through the fracture planes becomes limited
Solution Approach 1:
By dividing the thermal storage system into multiple independently controllable fracture planes, the system can distribute the water flow across multiple parallel pathways. This segmentation increases the total flow rate capability while maintaining sufficient storage capacity, as water can simultaneously charge or discharge multiple fracture planes rather than being constrained to a single flow path.
Solution Approach 2:
Each fracture plane serves multiple functions: it can be independently charged, independently discharged, or left idle based on system needs. This multi-functionality allows the system to optimize both storage capacity and flow rate by activating the appropriate number and combination of fracture planes depending on current thermal demands and available heat source capacity.
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 allows for flexible and efficient thermal energy storage and retrieval, adapting to current energy demands and improving the overall efficiency of the system by enabling partial or complete charging/discharging of the storage volume as needed.
Implementation Method 1
a storage for storing heat in rock is produced by fracturing the rock hydraulically in approximately plane parallel fissure planes from a number of boreholes
Implementation Method 2
Hot water is supplied to the system from the infiltration boreholes, where after the water flows through the store along flow paths defined by the fractured planes
Implementation Method 3
the water flows through the store along flow paths defined by the fractured planes and transverse channels towards one or more production holes
Implementation Method 4
The invention primarily relates to a thermal energy storage for storing energy in the form of heat in a rock formation
Data Source
AI summary
The invention relates to a thermal energy storage having a fluid source comprising one or more primary boreholes (110; 210; 311, 312, 313; 411, 412, 413; 511; 611; 711; 811; 911) extending from ground level to a predetermined depth in a rock body; and one or more secondary boreholes (120; 220; 751; 851; 951) located remote from the fluid source. At least an upper and a lower fracture plane (P1, P2, P3) intersects the one or more primary boreholes (110; 210; 311, 312, 313; 411, 412, 413; 511; 611; 711; 811; 911) and said secondary boreholes (120; 220; 751; 851; 951), which fracture planes (P1, P2, P3) permit a hydraulic flow of fluid between the primary borehole and at least one of the secondary boreholes (120; 220; 751; 851; 951). The fluid source comprises a well system comprising at least two wells (311, 312, 313; 431, 432, 433; 531, 532, 533; 631, 632, 633; 731; 831, 832, 833; 931) where each well is in fluid communication with one or more fracture planes; and where at least one sealing element positioned to prevent hydraulic flow between wells. The hydraulic flow in each well is controllable to permit a hydraulic flow of fluid between one or more primary boreholes (110; 210; 311, 312, 313; 411, 412, 413; 511; 611; 711; 811; 911) and at least one of the secondary boreholes (120; 220; 751; 851; 951) in at least one fracture plane (P1, P2, P3).