Inorganic high-temperature phase change energy storage material without precipitated salt

Abstract

The application discloses an inorganic high-temperature phase change energy storage material without precipitated salt, which is composed of inorganic main material 75-90% and phase change auxiliary agent 10-25% by weight percentage; the phase change auxiliary agent is a composite W / O emulsion material, which is composed of oil phase material 20-50%, emulsifier 1-5% and water phase mixed material 45-79% by weight percentage. The application has no inorganic salt precipitation and good material cycle stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage material production, and particularly relates to an inorganic high-temperature phase change energy storage material without precipitated salt. BACKGROUND

[0002] High-temperature inorganic phase change energy storage materials (melting point above 0 DEG C) can absorb or release a large amount of latent heat in the phase change process, and have the advantages of high enthalpy and low cost. Compared with organic phase change materials, inorganic materials have high thermal conductivity, and the cost is only about 4% to 5% of that of organic phase change materials, and have great cost advantage.

[0003] However, inorganic phase change energy storage materials also have many deficiencies:

[0004] Poor material stability: the principle of high-temperature inorganic phase change materials (melting point above 0 DEG C) is to synthesize inorganic salt hydrate to achieve high phase change temperature, so the prepared phase change material is a supersaturated aqueous solution, and a part of the inorganic salt cannot be dissolved and precipitated at the bottom of the liquid, which is very troublesome for filling and packaging, and with the increase of the number of uses, more and more salt is precipitated, which causes the phase change melting point to deviate, resulting in poor material stability.

[0005] In order to solve the problem of inorganic salt precipitation and poor material cycle stability, the currently used method is to add thickening agents such as superabsorbent resin, sodium carboxymethyl cellulose and the like to the material, but after adding the thickening agent, the enthalpy and phase change precision of the material will be poor, and it is not easy to batch fill. SUMMARY

[0006] The present application aims to solve the above problems in the prior art, and provides an inorganic high-temperature phase change energy storage material without precipitated salt, which has no inorganic salt precipitation and good material cycle stability.

[0007] The technical scheme adopted by the present application to solve the technical problems is:

[0008] An inorganic high-temperature phase change energy storage material without precipitated salt, consisting of 75-90% of inorganic main material and 10%-25% of phase change auxiliary agent by weight percentage.

[0009] The phase change auxiliary agent is a composite W / O emulsion material, which consists of 20%-50% of oil phase material, 1%-5% of emulsifier and 45%-79% of water phase mixed material by weight percentage.

[0010] The added phase change auxiliary agent needs to control the type and proportion of inorganic salt, and the inorganic salt needs to be quickly precipitated to form a stable phase change material with the inorganic material during crystallization.

[0011] Preferably, the inorganic main material is composed of 30% to 70% of inorganic phase change material and 30% to 70% of water by weight percentage.

[0012] Preferably, the inorganic phase change material is one or more of calcium chloride, sodium chloride, potassium chloride, magnesium chloride, ammonium chloride, sodium sulfate, sodium carbonate, sodium dihydrogen phosphate, and potassium carbonate.

[0013] Preferably, the oil phase material is one or more of C12-C26 saturated alkane (such as n-dodecane, n-tetradecane, n-eicosane), C12-C20 fatty acid (such as tetradecanoic acid, hexadecanoic acid, octadecanoic acid), and C12-C20 fatty acid ester (such as methyl dodecanoate, methyl tetradecanoate, methyl octadecanoate, ethyl octadecanoate, etc.).

[0014] Preferably, the water phase mixture material is composed of 30% to 50% of water, 30% to 40% of alcohol, and 10% to 40% of inorganic salt by weight percentage.

[0015] Preferably, the alcohol is one or more of ethanol, propanol, ethylene glycol, glycerol, and vinyl glycol.

[0016] Preferably, the inorganic salt is one or more of calcium chloride, sodium chloride, potassium chloride, magnesium chloride, ammonium chloride, sodium sulfate, sodium carbonate, sodium dihydrogen phosphate, and potassium carbonate.

[0017] Preferably, the emulsifier is one or more of ceteareth-12, ceteareth-20, ceteareth-30, Span 80, and Tween 80.

[0018] The inorganic salt phase change material is a supersaturated aqueous solution, and the main components are water, inorganic salt, and crystal nucleus agent. The main precipitate is inorganic salt, a part of which cannot be dissolved because the inorganic salt reaches saturation in water, and a part of which is precipitated because the high-temperature saturated solution is supersaturated at low temperature.

[0019] The traditional high-temperature inorganic phase change material is a supersaturated aqueous solution, and salt will be precipitated at the bottom. If the salt precipitated at the bottom is to be dissolved, the amount of water needs to be additionally increased, but directly adding water will affect the melting point of the material (directly changing from high-temperature to low-temperature phase change material). Therefore, the main innovative measure of the present application is to add a solvent system that can dissolve part of the precipitated salt to the original inorganic phase change system. This solvent system can form a uniform system with the entire inorganic phase change material, and most importantly, it can just dissolve the excess salt. During the phase change process, the salt in the solvent system can be precipitated before the inorganic phase change system, and mixed with the inorganic phase change material to form a complete phase change material. The precipitated salt can act as a crystal nucleus agent to accelerate the crystallization of the phase change material, and can effectively reduce the supercooling degree of the phase change material. In the present application, the salt part of the supersaturated system is dissolved by the solvent system, so that the inorganic main material part does not reach supersaturation and therefore will not produce precipitation. However, the total salt usage of the inorganic main material + phase change auxiliary agent is still the same as that of the supersaturated system.

[0020] The phase change auxiliary agent added in the present application has a melting point similar to that of the inorganic material, and contains water and alcohol that can dissolve salt. The difference in solubility at low temperature is used to adjust the melting point. This not only reduces the supercooling degree, but also increases the phase change enthalpy value and the viscosity of the phase change material due to the additional organic material, so that the precipitated salt can be uniformly distributed in the inorganic phase change material system, making the material more excellent in stability.

[0021] The W / O emulsion solvent added in the present application can effectively dissolve the precipitated inorganic salt and is sensitive to low temperature. During the low-temperature crystallization of the phase change material, the salt can be quickly precipitated and crystallized, together with the aqueous solution, to form a stable phase change material. During the warming process, the salt can be re-dissolved without precipitation.

[0022] The phase change auxiliary agent added in the present application does not affect the melting point and enthalpy value of the phase change material

[0023] The oil phase material selected for the phase change auxiliary agent added in the present application has a melting point close to that of the entire phase change material, so it will not affect the phase change melting point, and can improve the enthalpy value performance.

[0024] The water phase material needs to be mixed and matched between materials and matched in terms of ratio to control the melting point. The inorganic salt will exit the emulsion system after being precipitated, and will be combined with the inorganic main material to accurately control the melting point, so that the melting point of the phase change material will not be shifted.

[0025] The present application has the advantages of: no need to use crystal nucleus agent and thickening agent, no inorganic salt precipitation, and good material circulation stability. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The present application is a product comparison chart of Example 1 and Comparative Example 4. DETAILED DESCRIPTION

[0027] The technical solutions of the present application are further described below through specific examples.

[0028] In the present application, the raw materials and equipment used, unless specified, can be purchased from the market or commonly used in the art. The methods in the following examples, unless specified, are conventional methods in the art.

[0029] Preparation method of the present application:

[0030] 1. Preparation of phase change auxiliary agent:

[0031] After the oil phase material is heated and melted, water and alcohol are added and continue to stir until the temperature is stable, then emulsifier is added and stirred until a milky white liquid is formed, inorganic salt is added and stirred uniformly to form a phase change auxiliary agent.

[0032] 2. Preparation of inorganic material

[0033] After the inorganic main material is added with water and heated to 50°C, stirring for 30 minutes completes the preparation of the inorganic phase change material.

[0034] 3. Preparation of inorganic high-temperature phase change energy storage material

[0035] The phase change auxiliary agent is slowly added to the inorganic material at a temperature of 50°C, and stirred for 1 hour.

[0036] Example 1:

[0037] Step 1: Preparation of phase change auxiliary agent:

[0038] After 100 grams of dodecane and 500 grams of hexacosane are heated to 80°C and melted, 670 grams of water and 536 grams of ethylene glycol are added and continue to stir until the temperature is stable, then 60 grams of Span80 is added and stirred until a milky white liquid is formed, 104 grams of calcium chloride and 30 grams of ammonium chloride are added and stirred for 1 hour to form a phase change auxiliary agent.

[0039] Step 2: Preparation of inorganic material

[0040] After 100 grams of ammonium chloride and 800 grams of calcium chloride are added to 2100 grams of water and heated to 50°C, stirring for 30 minutes completes the preparation of the inorganic phase change material.

[0041] Step 3: Preparation of inorganic high-temperature phase change energy storage material

[0042] The phase change auxiliary agent 150g is slowly added to 850g of inorganic material at a temperature of 50°C, and stirred for 1 hour. Figure 1

[0043] Comparative Example 1 (without alcohol): ​

[0044] Step 1: Preparation of phase change auxiliary agent:

[0045] Take 100 grams of dodecane and 500 grams of hexacosane, heat to 80°C to melt, then add 1206 grams of water and continue stirring until the temperature is stable, then add 60 grams of Span 80 and stir until a milky white liquid is formed, add 104 grams of calcium chloride and 30 grams of ammonium chloride and stir for 1 hour to prepare the phase change auxiliary agent.

[0046] Step 2: Preparation of inorganic material

[0047] Take 100 grams of ammonium chloride and 800 grams of calcium chloride, add 2100 grams of water, then heat to 50°C and stir for 30 minutes to complete the preparation of the inorganic phase change material.

[0048] Step 3: Preparation of inorganic high-temperature phase change energy storage material

[0049] Slowly add 150g of phase change auxiliary agent to 850g of inorganic material at a temperature of 50°C, and stir for 1 hour.

[0050] Example 2:

[0051] Step 1: Preparation of phase change auxiliary agent:

[0052] Take 100 grams of dodecane and 500 grams of hexacosane, heat to 80°C to melt, then add 1206 grams of water and continue stirring until the temperature is stable, then add 60 grams of Span 80 and stir until a milky white liquid is formed, add 104 grams of calcium chloride and 30 grams of ammonium chloride and stir for 1 hour to prepare the phase change auxiliary agent.

[0053] Step 2: Preparation of inorganic material

[0054] Take 100 grams of ammonium chloride and 800 grams of calcium chloride, add 2100 grams of water, then heat to 50°C and stir for 30 minutes to complete the preparation of the inorganic phase change material.

[0055] Step 3: Preparation of inorganic high-temperature phase change energy storage material

[0056] Slowly add 150g of phase change auxiliary agent to 850g of inorganic material at a temperature of 50°C, and stir for 1 hour.

[0057] Comparative Example 2:

[0058] Step 1: Preparation of phase change auxiliary agent:

[0059] Take 100 grams of dodecane and 500 grams of hexacosane, heat to 80°C to melt, then add 1206 grams of water and continue stirring until the temperature is stable, then add 60 grams of Span 80 and stir until a milky white liquid is formed, add 104 grams of calcium chloride and 30 grams of ammonium chloride and stir for 1 hour to prepare the phase change auxiliary agent.

[0060] Step 2: Preparation of Inorganic Materials

[0061] Take 100 grams of sodium chloride and 800 grams of sodium sulfate, add them to 2100 grams of water, heat to 50°C and stir for 30 minutes to complete the preparation of inorganic phase change material.

[0062] Step 3: Preparation of Inorganic High-Temperature Phase Change Energy Storage Materials

[0063] At a temperature of 50℃, 150g of phase change auxiliary agent was slowly added to 850g of inorganic material and stirred for 1 hour.

[0064] Comparative Example 3

[0065] Take 100g of ammonium chloride and 800g of calcium chloride, add them to 2100g of water, heat to 50℃ and stir for 30 minutes to complete the preparation of inorganic phase change material.

[0066] Comparative Example 4 (Supersaturated)

[0067] 130 grams of ammonium chloride and 904 grams of calcium chloride were added to 2100 grams of water, and the mixture was heated to 50°C and stirred for 30 minutes to complete the preparation of the inorganic phase change material. Figure 1 ).from Figure 1 As can be seen, Comparative Example 4, which is a traditional high-temperature inorganic phase change material, is a supersaturated aqueous solution with salt precipitation, while the improved version of this invention does not precipitate.

[0068] The comparison results are shown in the table below:

[0069] In Comparative Examples 1 and 2, inorganic salt precipitation was not controlled, resulting in significant changes in phase transition temperature.

[0070] The results of the comparison of inorganic salt precipitation effects are as follows:

[0071]

[0072] Comparison of material cycle performance:

[0073]

[0074]

[0075] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Other variations and modifications are possible without departing from the technical solutions described in the claims.

Claims

1. An inorganic high temperature phase change energy storage material without precipitated salt, characterized in that, The inorganic main material is 75-90% by weight, and the phase change auxiliary agent is 10-25% by weight. The phase change auxiliary agent is a composite W / O emulsion material, which is composed of 20-50% of oil phase material, 1-5% of emulsifier, and 45-79% of water phase mixed material by weight percentage. The inorganic main material is composed of 30-70% of inorganic phase change material and 30-70% of water by weight percentage. The inorganic phase change material is one or more of calcium chloride, sodium chloride, potassium chloride, magnesium chloride, ammonium chloride, sodium sulfate, sodium carbonate, sodium dihydrogen phosphate, and potassium carbonate. The oil phase material is one or more of C12-C26 saturated alkane, C12-C20 fatty acid, and C12-C20 fatty acid ester. The water phase mixed material is composed of 30-50% of water, 30-40% of alcohol, and 10-40% of inorganic salt by weight percentage. The alcohol is one or more of ethanol, propanol, ethylene glycol, glycerol, and vinyl glycol.

2. The inorganic high-temperature phase change energy storage material of claim 1, wherein, The inorganic salt is one or more of calcium chloride, sodium chloride, potassium chloride, magnesium chloride, ammonium chloride, sodium sulfate, sodium carbonate, sodium dihydrogen phosphate, and potassium carbonate.

3. The inorganic high-temperature phase change energy storage material of claim 1, wherein, The emulsifier is one or more of cetyl stearyl alcohol polyether-12, cetyl stearyl alcohol polyether-20, cetyl stearyl alcohol polyether-30, Span 80, and Tween 80.

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