Thermochemical Storage Regulating Fluidization Gas for Constant Outlet Temperature
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Solution Overview
Problem
Existing thermochemical thermal storage systems for solar power plants fail to deliver a heat transfer fluid at a constant or substantially constant temperature, despite variations in thermal power input, which affects the efficiency of energy conversion and storage.
Innovation Solution
A thermochemical storage system with compartments forming fluidized beds, where the inlet speed of a fluidization gas is regulated based on thermal power input to control the quantity of storage material and maintain a constant outlet temperature, utilizing a multi-compartment design with fluidization gas and coolant circulation to achieve quasi-piston flow and improved heat exchange efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the thermal power input to the storage system varies, then the system can adapt to different operating conditions, but the outlet temperature of the heat transfer fluid becomes unstable
Solution Approach 1:
The system employs feedback control by regulating the inlet speed of the fluidization gas based on the thermal power input. The control unit adjusts the gas flow rate in response to thermal power variations, which in turn adjusts the quantity of storage material in the compartment, thereby maintaining stable outlet temperature of the heat transfer fluid despite input variations.
Solution Approach 2:
The system dynamically adjusts the inlet speed of the fluidization gas according to the thermal power input level. This dynamic regulation allows the quantity of storage material to be continuously optimized, enabling the system to adapt to varying thermal power conditions while maintaining constant outlet temperature.
2Temperature
If the inlet speed of fluidization gas is increased to control the quantity of storage material, then the temperature control improves, but the system complexity increases
Solution Approach 1:
The system replaces complex mechanical control mechanisms with a streamlined approach that regulates the inlet speed of the fluidization gas. This substitution simplifies the control system while achieving effective temperature control through gas flow regulation rather than complex mechanical adjustments of storage material quantity.
3Device complexity
If a fixed bed of reactant particles is used, then the system structure is simple, but the heat exchange efficiency is insufficient
Solution Approach 1:
The system changes the operational parameters by introducing fluidization gas that suspends and circulates the storage material particles. This parameter change transforms the static fixed bed into a dynamic fluidized bed, dramatically improving heat exchange efficiency between the heat transfer fluid and storage material while maintaining structural simplicity.
Solution Approach 2:
The system employs pneumatic principles by using fluidization gas to fluidize the storage material particles. The gas flow suspends and circulates the particles, creating intense mixing and contact between the storage material and heat transfer fluid, thereby significantly enhancing heat exchange efficiency compared to a static fixed bed structure.
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
The system effectively maintains a constant temperature of the coolant at the outlet, enhancing the efficiency of heat transfer and energy storage, allowing for greater variations in thermal power while maintaining a stable temperature gradient, thus optimizing energy conversion and storage processes.
Implementation Method 1
Heat storage can typically be achieved either as sensible energy (by varying the temperature level of a solid or liquid storage material), as latent energy (by changing the phase of a storage) or finally in the form of chemical energy (using endothermic and exothermic chemical reactions). Heat storage involving endothermic and exothermic chemical reactions is referred to as 'thermochemical storage'.
Implementation Method 2
Heat storage involving endothermic and exothermic chemical reactions is referred to as 'thermochemical storage'. During the charging phase, the thermal energy from, for example, a solar field via a heat transfer fluid, makes it possible to dehydrate the calcium hydroxide to form calcium oxide and water. Then, to restore the stored thermal energy, CaO and H2O are mixed and react to release the heat of reaction
Implementation Method 3
A thermochemical storage system with compartments forming fluidized beds, where the inlet speed of a fluidization gas is regulated based on thermal power input to control the quantity of storage material and maintain a constant outlet temperature, utilizing a multi-compartment design with fluidization gas and coolant circulation to achieve quasi-piston flow and improved heat exchange efficiency.
Data Source
Figure 1~2B
Figure 2C~3C
Figure 4~5B
AI summary
The invention relates to a thermochemical heat storage system comprising: three compartments (8.1, 8.2, 8.3) intended to contain a heat storage material (M); supply means (11) for supplying the compartments (8.1, 8.2, 8.3) with heat storage material; circulation means (10) for circulating a fluidising gas through the compartments (8.1, 8.2, 8.3) such as to form a fluidised bed, said fluidising gas being such that it generates thermochemical storage or release; circulation means (12) for circulating a heat-transfer fluid through the compartments (8.1, 8.2, 8.3) such as to provide heat exchanges with the storage material; and regulation means (13) for regulating the entry speed of the fluidising gas as a function of the thermal power carried by the heat-transfer fluid entering the storage system, such that the temperature of the heat-transfer fluid leaving the heat storage system is maintained substantially constant.