Sodium Sulfate Decahydrate PCM Stabilization
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Solution Overview
Problem
Sodium sulfate decahydrate-based temperature control and heat storage materials face issues with solid separation and stratification, leading to reduced heat storage capacity, and require eutectic compositions to achieve the human comfort temperature range of 16-28°C, which existing solutions do not adequately address for practical application.
Innovation Solution
A composition incorporating sodium sulfate decahydrate, copolymers, fibers, a fusion temperature-depressing salt, and a nucleating agent, where fibers form a uniform network to prevent settling and stratification, and the copolymers enhance dispersion, combined with a method of preparing the mixture to achieve high heat storage capacity and stable temperature control within the comfort range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If sodium sulfate decahydrate is used as a heat storage material, then the heat storage capacity is improved, but solid separation and stratification occur reducing effectiveness
Solution Approach 1:
The patent introduces copolymers as an intermediary substance that acts as a dispersant and stabilizer. The copolymers prevent solid separation and stratification of sodium sulfate decahydrate by maintaining uniform dispersion in the aqueous solution, thus resolving the contradiction between high heat storage capacity and composition stability.
Solution Approach 2:
The patent creates a composite material system combining sodium sulfate decahydrate with copolymers and fibers. This composite structure prevents the solid separation issue while maintaining the high heat storage capacity, as the copolymers and fibers form a stable matrix that keeps the sodium sulfate decahydrate uniformly distributed.
2Temperature
If eutectic composition is used to reach human comfort temperature range, then the temperature control range is improved, but the complexity of composition increases
Solution Approach 1:
The patent adjusts the composition parameters by incorporating specific ratios of sodium sulfate decahydrate, copolymers, and fibers to achieve the desired temperature range of 16-28°C. By optimizing these parameters, the patent achieves human comfort temperature control without excessive complexity in the composition formulation.
3Ease of manufacture
If inorganic PCMs are used, then the cost is reduced and availability is improved, but separation and stratification problems occur
Solution Approach 1:
The patent uses copolymers as an intermediary agent that prevents solid separation and stratification in inorganic PCMs. This allows the use of cost-effective inorganic materials like sodium sulfate decahydrate while improving their reliability and solidification performance through the stabilizing action of the copolymers.
4Stability of the object's composition
If organic PCMs are used, then separation and stratification are prevented, but cost increases and flammability risk appears
Solution Approach 1:
The patent adopts inorganic PCMs like sodium sulfate decahydrate which are inexpensive and readily available, replacing expensive organic PCMs. The addition of copolymers as a stabilizer prevents solid separation issues, achieving both cost-effectiveness and reliability without the flammability risks associated with organic materials.
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 composition achieves a heat storage capacity 3.6 times that of water and 6.7 times that of rock within the 16-28°C range, maintaining stability and effectiveness through hundreds of heating and cooling cycles, making it suitable for building temperature control and heat storage.
Implementation Method 1
PCMs use the 'latent' heat to store thermal energy. Solid-liquid PCMs are conventional and practical PCMs. The thermal energy transfer occurs when a material changes from a solid to a liquid or from a liquid to a solid. This is called a change in state, or 'phase'.
Implementation Method 2
when PCMs reach the temperature at which they change phase (their melting points) they absorb large amounts of heat without increasing temperature. When the temperature in environment around the PCM drops, the PCM solidifies, releasing its stored latent heat.
Implementation Method 3
fibres form a uniform network to prevent settling and stratification
Implementation Method 4
the copolymers enhance dispersion
Implementation Method 5
a nucleating agent... one problem is its tendency to super-cooling releasing large quantities of heat at undetermined times
Data Source
AI summary
The present invention discloses a composition for temperature control and heat storage consisting of sodium sulfate decahydrate, a compound of copolymers, a kind of fibers, a fusion temperature-depressing salt, a nucleating agent, and water, and a method of making it. The composition has high heat storage capacity and temperature control ability of about 35-65 Kwh/m3 within human comfort temperature level of 16 to 28° C., stable and suitable for temperature control and heat storage in buildings and houses.