JPS59122575A - Heat-storing material - Google Patents

Abstract

PURPOSE:A heat-storing material that is obtained by adding polyvinyl alcohol, formaldehyde, paraffin, as thickeners, to a system consisting of a specific amount of sodium acetate and water, thus showing stabilized heat dissipation properties, because it is free from phase separation, even when melting and freezing are repeated. CONSTITUTION:The objective heat-storing material is obtained by mixing 100pts.wt. of a sodium acetate-water system containing 53-69wt% of sodium acetate with thickeners, preferably consisting of 0.5-20pts.wt. of PVA, 0.1- 5pts.wt. of formaldehyde and 0.1-5pts.wt. of paraffin. USE:Heat-storing units for air-conditioning.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a latent heat storage material that utilizes the M latent heat of fusion of CH5cio 2Na @ 3 H2,0.

Conventional Structures and Problems There are known heat storage materials that utilize the sensible heat of substances and those that utilize latent heat. Heat storage materials that utilize latent heat are
Compared to heat storage materials that use sensible heat, it stores a large amount of heat per unit volume and per unit mass, and only requires a small amount to store the required amount of heat, making it possible to downsize the heat storage device. . However, heat storage materials that utilize latent heat can store heat at a constant temperature at a transition point, and can also radiate heat. In particular, heat storage materials that utilize the latent heat of fusion of inorganic hydrates are known to have a large amount of heat storage per unit volume.

In summary, conventionally I) 0H5CO2Na/3H20 is an inorganic hydrated substance with a large latent heat of fusion. However, cH3002Na
a 3H20(7) The melting point is not the harmonic melting point but the peritectic point, so as the melting and solidification are repeated, CH3CO
A so-called phase separation phenomenon occurs in which 2N& is deposited at the bottom of the container.

Therefore, the latent heat of fusion of CH3CO2Na/3H20 naturally decreases due to repeated heat storage and heat release. The decrease in latent heat accompanying this phase separation phenomenon causes C
This was a major problem when applying H3CO2Na/3H20 as a heat storage material.

Purpose of the Invention The object of the present invention is to provide a latent heat storage material that does not cause phase separation even after repeated melting and solidification and has extremely stable heat dissipation properties.
The system consists of adding and mixing polyvinyl alcohol (PvA), formaldehyde, and paraffin as thickeners to a system consisting of CH3CO2Na and H2O containing 53 to 693 to 69 parts by weight of sco2NIL. Preferably, the mixing amount of PVA is 0.6 to 20 parts by weight, the mixing amount of formaldehyde is 0.1 to 5 parts by weight, and the mixing amount of paraffin is 0.6 to 20 parts by weight, based on 100 parts by weight of the system consisting of CH3CO2Na and H2O. This is the case in the range of 1 to 5 parts by weight.

Description of Examples Commercially available reagents CH3C0zNa-3H20, *lumaldehyde, PVA, paraffin and H2O were
A predetermined amount was blended to obtain the composition shown in the table. Regarding pvA, the degree of polymerization is about 600, about 16c.

About 2,000 types of paraffin were used, and commercially available liquid paraffin was used.

Paraffin with a melting point of 42°C to 44°C, a melting point of 64°C to
Experiments were conducted on three types of paraffin at 66°C.

(Left below) Heat the mixture in a predetermined amount to about 70'G, and
3CO2Na.3H20 and paraffin were melted and stirred vigorously for about 60 minutes using a stirrer. the result,
A white viscous liquid was obtained. Obtained sample approximately 100y
- was sealed in a capsule with CH3CO2Na-3H20 (D supercooling prevention material NaaP20710H200,5y-.Then, the latent heat of each sample was measured by the drop method.The capsule containing the sample was
After heating and holding at 7 o'C for about 3 hours to melt the sample, the temperature was lowered to about 60°C and held for about 4 more hours. Thereafter, the sample was placed in a thermos bottle containing water at approximately 30°C, and the latent heat of the sample was determined from the rise in water temperature at that time. After that, the capsule containing the sample was placed in a water bath and heated to 700C.
Heating and cooling were repeated 1000 times between and 36°C. At that time, the latent heat after 100 times and after 1000 times was measured by the above-mentioned drop method. The results are shown in Table 2. In Table 2, as an evaluation, those with a latent heat of 45 cal/f or more after repeated heating and cooling 100 degrees are marked with an ○, and those with a latent heat of 40
Al/f or more 454? If it is less than 4, mark it with Δ.
Those with a value less than 00Vγ are marked with an X. By the way, as a matter of course, those marked with ○ have a large amount of heat storage and can be put to practical use, and those marked with Δ have a not so large amount of heat storage, but the heat storage material operates stably, so it is sufficient for practical use. is considered possible.

(Left below) Analyze the takes in Table 2. Samples 1 to 10 are C
H3C02Na (7) 2 parts by weight of PVA, 0.6 parts by weight of formaldehyde, and 1.0 parts by weight of paraffin were added to 100 parts by weight of a system consisting of CH3CO2Na and H2O whose content was varied from 62% by weight to 70% by weight. Parts by weight were added and mixed. CH3GO2Na content is 62
For sample 1, which is commercially available, the amount of heat released during the first solidification is:
The latent heat is as large as 55 cal/y-, or as small as 37 J7'p after melting and solidification is repeated 1000 times. C
CHsCO2Na, a system consisting of H3C02Na and H2O
In sample 2, in which the content of
The latent heat after repeating 000 times is 60071/jf,
It is considerably larger than Sample 1. And CH3C
The system consisting of O2Na and H2O or OH3GO2NIL is 5
Samples 2 to 6 containing a weight ratio of 4 to 68 had a latent heat of 5oωvy even if melting and solidification were repeated 1000 times.
t or more. However, in sample 1o, which has a CH3CO2Na (7) content of 70% by weight, which is a system consisting of CH3CO2Na and H2O, the latent heat after 1000 cycles is 39 cal.
7'y-, which is considerably smaller than Sample 3, which has a large latent heat. In addition, among heat storage materials containing thickeners, the ones with maximum latent heat are CHsco 2N2L and H
The composition of the system consisting of 2O is the electric ratio composition of CH3C02Na-3H20, that is, the composition on the H20 excess side from the 60.28 commercial quantity of CH3CO2Na, that is, CH3co2Na
It can be seen that the weight ratio is around 6-58.

Samples 11 to 1 represent a system consisting of CHsCO2Na and H2O containing 56 weights of OH3GO2N&.
Heavy dispersion part, 2 parts by weight of PVA, 0.5 parts by weight of formaldehyde
It is constant with the amount of ITf (the amount of paraffin mixed is
It is a change from 1 to 10 market volume.

・In sample 11, which does not have ζ rat twin 2JA, the first
The latent heat after the 100th cycle is 50 tvV f , and the latent heat after the 1000th cycle is 38 caV y -, which is a large decrease. In sample 12, in which 0.1 part by weight of paraffin was mixed, the latent heat after 1000 cycles was 49 e/), which is considerably larger than sample 11. In samples 13 to 16 containing paraffin in the range of 0.5 parts by weight to 6 parts by weight, 1,000 parts by weight
The latent heat after rotation is as large as 60ωIl/y- or more. However, in sample 17 in which 10 parts by weight of paraffin was mixed, 1000
The latent heat after rotation decreases to 44ωVy-.

Samples 18 to 22 contain 10% of the system consisting of CH3CO2Na and H2O containing 66% by weight of CH3CO2Na.
0 parts by weight, PVA at 2 parts by weight, and paraffin at 1 part by weight, and the amount of formaldehyde mixed was varied in the range from ○ to 10 parts by weight. In sample 18, which does not contain formaldehyde, the latent heat at the first time is as large as 58ωI/y-, but after 100 times it is 48ωI/y-.
aivf becomes small to 38, l/y- after 1000 times. In sample 19, in which 0.1 part by weight of formaldehyde was mixed, the latent heat after 1000 cycles was 48 cJy-, and the degree of decrease in kana was smaller than in sample 18. Sample 20 containing formaldehyde in the range of 0.2 parts by weight to 5 parts by weight. In sample 21, the latent heat after 1000 cycles is as large as 6oa17y- or more. However, in sample 22 in which 10 parts by weight of formaldehyde was mixed, 1000
The latent heat after cooling decreases to 44d/7.

Samples 23 to 29 contained 100 parts by weight of CH3CO2Na (!l:H20) containing 56% by weight of CHsho 2Na, 0.5 parts by weight of formaldehyde,
Nosilafine was kept constant at 1 part by weight, and PVA was varied from 0 to 30 parts by weight.

Sample 23, which did not contain PVA, was tested for the first time.

In sample 24 containing 0.1 part by weight of PVA, 1000
The latent heat after heating is 43ωβ/l, which is considerably larger than that of sample 23. Samples 25 to 27 containing PVA in a range of 0.6 parts by weight to 10 parts by weight had large latent heats of more than cs o c, p/y after 1000 cycles. However, in sample 29 in which 30 parts by weight of PVA was mixed, the latent heat after 1o-oo cycles is 430Z4/ψ, which is considerably smaller than that of sample 2θ.

In Samples 30 and 31, commercially available liquid paraffin was used as paraffin, but paraffin with a melting point higher than room temperature was used. There is almost no difference in latent heat compared to when liquid paraffin is used.

Sample 32 and Sample 33 have a polymerization degree of about 150 as PVA.
0 and about 2o00. In this case as well, there is no noticeable difference in latent heat from that when PVA with a degree of polymerization of 600 is used.

As shown above, CH3CO2Na is 53~693~
CH3CCl2Na containing 69 parts by weight (!: H2
By mixing PVA, formaldehyde, and paraffin as thickeners with 100 parts by weight of a system consisting of O, it is possible to obtain a heat storage material with stable performance in which the amount of heat storage hardly changes even after repeated melting and solidification. can. The desirable composition is the composition region marked with a circle in Table 2, that is, CHsCOzNa and H2O.
0.5 to 2 parts of PVA to 100 parts by weight of the system consisting of
0 parts by weight, formaldehyde in the range of 0.1 to 6 parts by weight, and paraffin in the range of 0.1 to 6 parts by weight.

PV
A crosslinks with each other by the action of formaldehyde,
Paraffin is dispersed in the heat storage material melt, increases the viscosity of the heat storage material melt, and prevents precipitation of OH3GO2N2L.The paraffin acts as an interface between the heat storage material melt and PVA, thereby increasing the viscosity of the heat storage material melt.
As 2Na113H20 melts and solidifies, the melt and PV
It is thought that this prevents A from separating.

Effects of the Invention As described above, the present invention provides OHsho 2Na containing CH3co 2Na in a range of 53% to 69% by weight.
The heat storage material is a mixture of PVA, formaltech, and halafine as thickeners to prevent phase separation in a system consisting of has. Therefore, the present invention is applicable to all fields that utilize heat storage, including heat storage devices for air conditioning.

Claims (2)

[Claims] (1) Sodium acetate (CH3CO2N &) 53-6
A heat storage material characterized in that it is a mixture of a system consisting of sodium acetate and water containing 93 to 69 parts by weight, to which polyhinyl alcohol, formaldehyde and paraffin are added as thickeners. (2) 0.6 to 20 parts by weight of borihinyl alcohol and 0.1 to 5 parts by weight of formaldehyde per 10 parts by weight of the system consisting of sodium acetate and water. The heat storage material according to claim 1, characterized in that paraffin is added and mixed in an amount of 0.1 to 5 parts by weight.