Underground Solid-Medium Heat Storage for Concentrating Solar Power
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Solution Overview
Problem
Conventional concentrating solar power (CSP) plants face high design complexity, initial costs, and operation and maintenance challenges due to elevated system components, and inefficiencies in steam turbines when using molten salts for heat storage, which limits temperature and efficiency.
Innovation Solution
A CSP system with a solar light capturing part and a heat exchange part that uses a solid medium for thermal energy storage underground, where solar light is reflected to a compound concentrator, heating the solid medium, which is then circulated and transferred to a fluid to generate steam for electricity production, utilizing a conveyor system to distribute heat uniformly and integrate seawater distillation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If molten salts are used as heat storage material in conventional CSP plants, then the system can store thermal energy, but the temperature is limited to 600°C due to chemical instability above this temperature
Solution Approach 1:
The patent changes the physical state parameter of the heat storage material from liquid (molten salt) to solid (particles), enabling operation at temperatures above 600°C where molten salts become chemically unstable. This parameter change allows the system to achieve higher temperatures while maintaining material stability.
Solution Approach 2:
The patent uses solid particles as heat storage material that can be continuously circulated and replaced through the system. The particles serve their function during circulation and can be replenished, providing a cost-effective solution for high-temperature heat storage without the chemical stability constraints of molten salts.
2Temperature
If all components including falling particle receiver and storage tanks are located in a solar tower at height of 15m, then high temperature heat storage is achieved, but design complexity and initial costs increase significantly
Solution Approach 1:
The patent divides the CSP system into separate functional modules: the solar tower for concentration, the particle circulation system for heat transfer, and ground-level storage tanks for heat storage. This segmentation allows each component to be optimized independently and simplifies overall system design and maintenance.
Solution Approach 2:
The patent moves the storage tanks from vertical placement in the solar tower to horizontal placement on the ground, utilizing the ground level space. This dimensional change eliminates the need for complex elevated structures while maintaining the heat storage function, thereby reducing design complexity and initial costs.
3Power
If conventional steam turbines are used with falling particle receiver, then electricity generation is possible, but efficiency is reduced due to temperature mismatch
Solution Approach 1:
The patent introduces a heat transfer fluid as an intermediary between the solid particles and the steam turbine. The fluid absorbs heat from the particles and transfers it to the steam cycle, enabling efficient energy transfer across the temperature gap and maximizing power plant efficiency.
Solution Approach 2:
The patent replaces the direct thermal coupling system with a fluid-mediated heat transfer system. This substitution allows for better temperature matching and heat transfer efficiency, improving overall productivity while maintaining electricity generation capability.
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 configuration reduces system complexity and costs while achieving higher temperatures and efficiencies, enabling efficient electricity generation and seawater desalination with improved energy utilization and reduced environmental impact.
Implementation Method 1
The solar light capturing part has a heliostat farm, a beam down solar concentrator, and a compound concentrator, each configured to reflect the solar light
Implementation Method 2
a heat exchange part configured to transform solar energy, from the captured solar light, into heat
Implementation Method 3
spreading the heat uniformly in the solid medium by moving the solid medium from a bottom of the storage tank to a top of the storage tank with a conveyor system
Implementation Method 4
transferred the heat from the solid medium to a liquid that flows through a coil located in the storage tank
Implementation Method 5
boiling water in a boiler, based on the heated liquid
Implementation Method 6
generating the electrical energy with a turbine based on steam obtained by boiling the water
Data Source
AI summary
A concentrating solar power plant includes a solar light capturing part configured to capture solar light; and a heat exchange part configured to transform solar energy, from the captured solar light, into heat, which is stored in a solid medium, wherein the solid medium is stored underground. The solar light capturing part has a heliostat farm, a beam down solar concentrator, and a compound concentrator, each configured to reflect the solar light.