Fluidized Granular Bed Thermal Storage for Continuous Heat Extraction
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Solution Overview
Problem
Existing solar energy storage systems face challenges with thermal stress on heat exchangers, inefficiency in thermal energy conversion, and limited versatility due to day/night cycles and atmospheric conditions, leading to potential breakage and suboptimal energy production.
Innovation Solution
A device utilizing a fluidizable granular bed for thermal energy storage, where a fluidization gas moves particles to enhance heat exchange with pipe bundles, allowing for efficient and reliable storage and adaptation to energy demands, with the option to burn gaseous fuel for increased flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a block of material with high thermal conductivity (graphite) is used for thermal energy storage, then thermal energy storage capacity is improved, but thermal stress on heat exchanger pipes increases leading to potential breakage
Solution Approach 1:
The patent replaces solid graphite block with a porous graphite structure that allows fluid circulation through channels. This maintains thermal storage capacity while enabling controlled heat extraction that prevents thermal shock to pipes. The porous structure with interconnected pores and channels allows gradual heat transfer rather than sudden thermal stress.
Solution Approach 2:
The patent introduces a fluid circulation system where working fluid flows through channels in the porous graphite block. This hydraulic approach enables controlled heat extraction rates, preventing sudden temperature changes that would cause thermal stress. The fluid acts as an intermediate heat transfer medium, smoothing out thermal fluctuations.
2Use of energy by moving object
If thermal energy storage is linked to atmospheric conditions and day/night cycles, then solar energy storage is achieved, but continuity of heat removal and adaptability to energy requirements deteriorates
Solution Approach 1:
The patent creates a multi-functional system where the porous graphite block serves both as thermal energy storage medium and as a structure with integrated fluid channels for heat extraction. The system can operate in multiple modes: charging during day, discharging at night, and maintaining continuous operation by controlling fluid flow rates to match energy demand patterns.
Solution Approach 2:
The patent implements dynamic control of fluid flow through the porous structure. By adjusting flow rates and circulation patterns, the system can adapt to varying energy requirements in real-time, providing continuous heat removal regardless of atmospheric conditions or time of day. The fluid circulation system responds dynamically to maintain thermal energy balance.
3Power
If metal pipe bundles are used in heat exchangers for high temperature thermal energy transfer, then heat transfer efficiency is improved, but resistance to thermal shock and mechanical stress deteriorates
Solution Approach 1:
The patent uses porous graphite material with embedded channels instead of dense metal pipe bundles. The porous structure provides large surface area for heat transfer while being inherently more resistant to thermal shock. The graphite material can accommodate thermal expansion and contraction without the brittle failure modes of metal pipes at high temperatures.
Solution Approach 2:
The patent creates a composite heat exchange structure where graphite material serves as both thermal storage medium and heat transfer pathway. This composite approach combines the high thermal conductivity of graphite with its superior thermal shock resistance, eliminating the need for separate metal pipe bundles that are vulnerable to thermal stress.
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 minimizes thermal stresses on exchangers, increases thermal exchange efficiency, ensures continuous heat extraction, and adapts to downstream energy requirements, providing flexible and efficient energy production.
Implementation Method 1
a fluidization gas moves the particles of the bed causing or fostering a heat exchange between the particles themselves and the pipe bundles
Implementation Method 2
wherein said concentrated solar radiation is stored in said storage means
Implementation Method 3
The heat stored in the receptor block is transferred to such working fluid in order to produce vapor or heat for industrial plants
Data Source
Figure 1
Figure 1a
Figure 2
AI summary
A device (1) for storage and conveyance of thermal energy for an energy production system, which device (1) is apt to receive the solar radiation and is based on the use of a modular fluidizable granular bed and a heat exchanger associated thereto. The modular fluidization allows the selective storage of heat or thermal transfer to the exchanger. At the basis of such use, there are the favorable features of thermal exchange of the fluidized beds and the effective convective conveyance of the heat subsequent to the mobility of the granular phase. Both these features are linked to the possibility of imparting a rheological behavior to a granular solid that is comparable to that of a fluid, actually thanks to the fluidization thereof. Such device mainly comprises: - a containment casing (2) provided with one or more cavities receiving the solar radiation (20); - a fluidizable bed of granular particles (3) suitable for thermal energy storage and conveyance, arranged inside the containment casing (2); - one feed inlet for feeding a fluidization gas through the bed (3) of particles by a suitable distributor (21); - a heat exchanger (4) immersed in the fluidizable granular bed and crossed by a working fluid; and - a feeding inlet for a fuel gas (401) as additional thermal input to increase the system management flexibility.