Solid Particle CSP Heat Transfer for High-Temperature Storage
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Solution Overview
Problem
Current Concentrating Solar Power (CSP) systems face limitations due to the high cost and temperature constraints of existing heat transfer fluids like molten salt, which restrict system efficiency and increase costs, especially in thermal energy storage and energy conversion.
Innovation Solution
The introduction of a CSP system utilizing gas-solid two-phase flow and solid particles as thermal energy storage media, which avoids the temperature limitations of liquid heat transfer fluids and enables high-temperature operation and efficient heat transfer through a solid particle receiver and fluidized-bed heat exchanger.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If molten salt is used as heat transfer fluid, then thermal energy storage is enabled, but temperature limitations (upper limit 565°C) restrict system efficiency
Solution Approach 1:
The patent changes the physical state parameter of the heat transfer medium from liquid (molten salt) to solid (particles), enabling operation at temperatures above 565°C while maintaining system stability through the inherent properties of solid particles that do not freeze or become unstable at high temperatures
Solution Approach 2:
The patent uses inexpensive solid particles (such as rocks, pebbles, or ceramic particles) as the heat transfer medium, replacing expensive molten salt. These particles can be continuously circulated and replaced without significant cost, enabling high-temperature operation without the stability constraints of molten salt
2Temperature
If synthetic oil is used as heat transfer fluid, then heat transfer is achieved, but upper temperature limit of 390°C limits power generation efficiency
Solution Approach 1:
The patent changes the heat transfer medium from synthetic oil to solid particles, raising the maximum operating temperature from 390°C to above 565°C, which directly improves power generation efficiency by enabling higher temperature differential in the heat engine cycle
3Productivity
If direct steam generation is used, then power generation is achieved, but complex controls and limited thermal storage capacity are required
Solution Approach 1:
The patent segments the power generation process into two independent stages: (1) solid particles transfer thermal energy to a heat transfer fluid in a heat exchanger, and (2) the heated fluid drives the power cycle. This separation simplifies control by decoupling the thermal storage function from the power generation control
Solution Approach 2:
The patent introduces solid particles as an intermediary heat transfer medium that carries thermal energy from the solar receiver to the heat exchanger, where it transfers heat to the working fluid. This intermediary approach simplifies control compared to direct steam generation while enabling substantial thermal storage capacity
4Quantity of substance
If two-tank molten salt storage system is used, then thermal energy storage is achieved, but high costs and temperature limitations are imposed
Solution Approach 1:
The patent uses inexpensive solid particles (rocks, pebbles, ceramic particles) as the thermal energy storage medium, replacing expensive molten salt. These particles cost a fraction of molten salt and can be continuously circulated, dramatically reducing the cost of thermal energy storage while maintaining or increasing storage capacity
Solution Approach 2:
The patent changes the thermal energy storage medium from molten salt to solid particles, enabling operation beyond 565°C and eliminating freezing issues below 200°C, while using low-cost materials that reduce overall system cost despite the elimination of expensive containment systems
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 solution enhances solar-to-electric conversion efficiency, reduces system costs, and increases thermal energy storage capacity by allowing high-temperature operation and efficient heat transfer, overcoming the limitations of traditional heat transfer fluids.
Implementation Method 1
a solid particle receiver configured to heat granular solid particles flowing therethrough using energy from solar flux incident thereon
Implementation Method 2
the granular solid particles are fluidized by a gas to form a gas-solid fluid. The gas-solid fluid is circulated through a heat exchanger to transfer heat from the solid particles in the gas-solid fluid to a working fluid
Implementation Method 3
transfer heat from the solid particles in the gas-solid fluid to a working fluid
Data Source
AI summary
Embodiments described herein relate to a method of producing energy from concentrated solar flux. The method includes dropping granular solid particles through a solar flux receiver configured to transfer energy from concentrated solar flux incident on the solar flux receiver to the granular solid particles as heat. The method also includes fluidizing the granular solid particles from the solar flux receiver to produce a gas-solid fluid. The gas-solid fluid is passed through a heat exchanger to transfer heat from the solid particles in the gas-solid fluid to a working fluid. The granular solid particles are extracted from the gas-solid fluid such that the granular solid particles can be dropped through the solar flux receiver again.