Low-temperature calcium chloride hexahydrate heat-storage material and preparation method

Abstract

The invention discloses a low-temperature calcium chloride hexahydrate heat-storage material and a preparation method. The prepared low-temperature calcium chloride hexahydrate phase-change heat-storage material comprises a nucleating agent and a thickener according to mass percent, wherein the nucleating agent is borax, alumina or sodium metasilicate nonahydrate, the thickener is sodium carboxymethl cellulose (CMC), wherein calcium chloride hexahydrate is a phase-change base material, and the usage amount of the calcium chloride hexahydrate is 95%-98%; the preparation method comprises the step of: respectively adding 1wt% of borax and 1% of CMC or 1% alumina and 4% of CMC or 1% of sodium metasilicate nonahydrate and 2% CMC for modifying the calcium chloride hexahydrate, to obtain the low-temperature calcium chloride hexahydrate heat-storage material. The phase-change latent heat of the low-temperature calcium chloride hexahydrate heat-storage material is about 150J / g, the phase-change temperature of the low-temperature calcium chloride hexahydrate heat-storage material is at 25-30DEG C, the cooling degree is less than 2DEG C, and the heat suction and release performances of the low-temperature calcium chloride hexahydrate heat-storage material after being circulated for 3000 times are stable. The low-temperature calcium chloride hexahydrate heat-storage material has excellent application prospects in agricultural facilities and residential housing.

Description

technical field

[0001] The invention relates to a phase change heat storage material, in particular to a calcium chloride hexahydrate heat storage material with a subcooling degree of less than 2°C and no phase separation, and a preparation method thereof. Background technique

[0002] After 30 years of development, the scale and technology of energy-saving solar greenhouses have been significantly improved. The proportion of this type of greenhouse in agriculture is getting higher and higher, and it has become an important agricultural building for farmers in the north to increase their income. The solar greenhouse is a vegetable cultivation facility with Chinese characteristics, which can make full use of solar energy. In the northern region, it is generally possible to produce vegetables overwintering without heating. However, in the cold northern regions, the lowest temperature in winter will reach minus 10°C or even lower, causing the temperature in the greenhouse to dr...

Examples

preparation example Construction

[0026] The preparation method of the above-mentioned low-temperature calcium chloride hexahydrate heat storage material uses calcium chloride hexahydrate as the phase change basic material, and adds a nucleating agent and a thickener therein for modification, including the following steps:

[0027] 1) Slowly add anhydrous calcium chloride into hot water at a constant temperature of 50°C until the anhydrous calcium chloride no longer dissolves and precipitates, then filter to obtain a saturated solution of pure calcium chloride;

[0028] 2) Put the pure calcium chloride saturated solution in a constant temperature environment at 5°C, cool down and crystallize the saturated calcium chloride solution to obtain calcium chloride hexahydrate crystals; place the calcium chloride hexahydrate crystals at a low temperature of 5°C to dry Low-temperature drying in the environment to obtain pure calcium chloride hexahydrate crystals;

[0029] 3) Add a nucleating agent and a thickener to pu...

Embodiment 1

[0033] In this example, anhydrous calcium chloride, borax and sodium carboxymethylcellulose (CMC) are used as raw materials to prepare low-temperature calcium chloride hexahydrate phase-change thermal storage materials, wherein the amount of anhydrous calcium chloride is 98% (mass ratio ), the amount of borax is 1% (mass ratio), and the amount of sodium carboxymethylcellulose is (CMC) 1% (mass ratio). First, pure calcium chloride hexahydrate crystals are obtained by dissolving and cooling crystallization. Add borax and sodium carboxymethylcellulose (CMC) to calcium chloride crystals. In this example, borax is used as a nucleating agent and sodium carboxymethylcellulose (CMC) is used as a thickener. Heat to 40°C until liquid, and stir uniform. The homogeneous solution is placed below 20°C for 24 hours to form a solidified calcium chloride hexahydrate thermal storage material.

[0034] like figure 1 As shown, the test by the applicant shows that the low-temperature calcium chl...

Embodiment 2

[0036] This example also adopts the method of Example 1 to prepare low-temperature calcium chloride hexahydrate heat storage material, using anhydrous calcium chloride, aluminum oxide and sodium carboxymethylcellulose (CMC) as raw materials, wherein anhydrous calcium chloride The dosage is 95% (mass ratio), and the dosage of alumina is 1% (mass ratio). The amount of sodium carboxymethylcellulose (CMC) is 4% (mass ratio). In this example, aluminum oxide is used as a nucleating agent and sodium carboxymethylcellulose (CMC) is used as a thickener. First, it is obtained by dissolving and cooling crystallization. Pure calcium chloride hexahydrate crystals, add aluminum oxide and sodium carboxymethylcellulose (CMC) to pure calcium chloride hexahydrate crystals, heat to 40°C until liquid, and stir evenly. Put the homogeneous solution below 20°C for 24 hours to form a solidified calcium chloride hexahydrate heat storage material. The coldness is less than 2°C and there is no phase se...

technical field

[0001] The invention relates to a phase change heat storage material, in particular to a calcium chloride hexahydrate heat storage material with a subcooling degree of less than 2°C and no phase separation, and a preparation method thereof. Background technique

[0002] After 30 years of development, the scale and technology of energy-saving solar greenhouses have been significantly improved. The proportion of this type of greenhouse in agriculture is getting higher and higher, and it has become an important agricultural building for farmers in the north to increase their income. The solar greenhouse is a vegetable cultivation facility with Chinese characteristics, which can make full use of solar energy. In the northern region, it is generally possible to produce vegetables overwintering without heating. However, in the cold northern regions, the lowest temperature in winter will reach minus 10°C or even lower, causing the temperature in the greenhouse to dr...

Examples

preparation example Construction

[0026] The preparation method of the above-mentioned low-temperature calcium chloride hexahydrate heat storage material uses calcium chloride hexahydrate as the phase change basic material, and adds a nucleating agent and a thickener therein for modification, including the following steps:

[0027] 1) Slowly add anhydrous calcium chloride into hot water at a constant temperature of 50°C until the anhydrous calcium chloride no longer dissolves and precipitates, then filter to obtain a saturated solution of pure calcium chloride;

[0028] 2) Put the pure calcium chloride saturated solution in a constant temperature environment at 5°C, cool down and crystallize the saturated calcium chloride solution to obtain calcium chloride hexahydrate crystals; place the calcium chloride hexahydrate crystals at a low temperature of 5°C to dry Low-temperature drying in the environment to obtain pure calcium chloride hexahydrate crystals;

[0029] 3) Add a nucleating agent and a thickener to pu...

Embodiment 1

[0033] In this example, anhydrous calcium chloride, borax and sodium carboxymethylcellulose (CMC) are used as raw materials to prepare low-temperature calcium chloride hexahydrate phase-change thermal storage materials, wherein the amount of anhydrous calcium chloride is 98% (mass ratio ), the amount of borax is 1% (mass ratio), and the amount of sodium carboxymethylcellulose is (CMC) 1% (mass ratio). First, pure calcium chloride hexahydrate crystals are obtained by dissolving and cooling crystallization. Add borax and sodium carboxymethylcellulose (CMC) to calcium chloride crystals. In this example, borax is used as a nucleating agent and sodium carboxymethylcellulose (CMC) is used as a thickener. Heat to 40°C until liquid, and stir uniform. The homogeneous solution is placed below 20°C for 24 hours to form a solidified calcium chloride hexahydrate thermal storage material.

[0034] like figure 1 As shown, the test by the applicant shows that the low-temperature calcium chl...

Embodiment 2

[0036] This example also adopts the method of Example 1 to prepare low-temperature calcium chloride hexahydrate heat storage material, using anhydrous calcium chloride, aluminum oxide and sodium carboxymethylcellulose (CMC) as raw materials, wherein anhydrous calcium chloride The dosage is 95% (mass ratio), and the dosage of alumina is 1% (mass ratio). The amount of sodium carboxymethylcellulose (CMC) is 4% (mass ratio). In this example, aluminum oxide is used as a nucleating agent and sodium carboxymethylcellulose (CMC) is used as a thickener. First, it is obtained by dissolving and cooling crystallization. Pure calcium chloride hexahydrate crystals, add aluminum oxide and sodium carboxymethylcellulose (CMC) to pure calcium chloride hexahydrate crystals, heat to 40°C until liquid, and stir evenly. Put the homogeneous solution below 20°C for 24 hours to form a solidified calcium chloride hexahydrate heat storage material. The coldness is less than 2°C and there is no phase se...

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