Attapulgite Salt Hydrate Composite for Low-Temp Thermochemical Storage
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Solution Overview
Problem
Current materials for thermochemical heat storage, such as silica gel and zeolites, have high charging temperatures, limiting their ability to store thermal heat at low temperatures, and no economically viable alternatives with comparable storage density exist for temperatures below 110°C.
Innovation Solution
A composite material comprising a porous substrate material, specifically attapulgite, directly combined with salt hydrates without chemical activation, where the attapulgite is thermally activated and modified to enhance porosity, enabling efficient thermal energy storage at temperatures between 90°C and 110°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silica gel or zeolite is used for thermochemical heat storage, then storage density is high, but charging temperature is too high for low-temperature waste heat utilization
Solution Approach 1:
The invention changes the material parameters by selecting salt hydrates with specific phase transition temperatures (90-110°C) that match low-temperature waste heat sources, thereby resolving the contradiction between maintaining high storage density and reducing charging temperature to enable utilization of low-temperature thermal energy
Solution Approach 2:
The invention creates a composite material system combining porous substrate (activated carbon, attapulgite, or silica gel) with salt hydrate (CaCl2·6H2O, MgCl2·6H2O, or Na2SO4·10H2O), where the porous substrate provides high surface area for heat transfer and the salt hydrate provides the phase transition mechanism at low temperatures, achieving both high storage density and low charging temperature
2Volume of stationary object
If chemical activation or impregnation is used to prepare the substrate, then porosity is enhanced, but process complexity and chemical treatment requirements increase
Solution Approach 1:
The invention employs readily available commercial activated carbon, attapulgite, or silica gel materials that already possess sufficient porosity for the application, eliminating the need for complex chemical activation or impregnation processes. This approach uses simple, inexpensive materials with adequate properties rather than attempting to enhance already-sufficient materials through complicated procedures
Solution Approach 2:
The invention extracts and eliminates the unnecessary chemical activation and impregnation steps from the material preparation process, using only simple mixing and drying operations while maintaining adequate porosity through careful selection of the porous substrate material itself
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 composite material achieves high adsorption capacities and energy density, with attapulgite-based composites showing improved hydrothermal stability and dynamic performance, effectively storing thermal energy at low temperatures with minimal losses over multiple cycles.
Implementation Method 1
a composite material for thermochemical storage... comprising a porous substrate material and a salt hydrate
Implementation Method 2
Porous storage materials have received significant interest in recent years for adsorption thermochemical heat storage applications
Implementation Method 3
The substrate material may be a mesoporous material. Pore sizes in the range of 2 nm to 50 nm are called mesopores.
Implementation Method 4
These material pairs exhibit good storage characteristics including high storage density
Implementation Method 5
The attapulgite may be thermally activated before the salt hydrate is added in order to remove water molecules from pores of the material. For example, the attapulgite may be calcinated, e.g. by temperatures of 400 °C, 550 °C, or 700 °C.
Data Source
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AI summary
The disclosure refers to a composite material for thermochemical storage comprising a porous substrate material and a salt hydrate, wherein the salt hydrate is arranged directly on the substrate material. Further, a method for forming a composite material for thermochemical storage, the method comprising steps of providing a porous substrate material, and arranging a salt hydrate directly on the substrate material is disclosed