Heat source material composition, and auxiliary heat source and heat supply method using the same

Abstract

A heat storage material composition, at least containing at least one organic compound selected from ethanol, ethylene glycol, propylene glycol, and acetic acid, sodium acetate, and water, wherein a content of the water is 72.4 to 100 parts by mass, relative to 100 parts by mass of the sodium acetate; an auxiliary heat source and a heat supply method, using the heat storage material composition.

Claims

1. A heat storage material composition, consisting of: (a) an organic compound consisting of ethanol, ethylene glycol, propylene glycol, or acetic acid, (b) sodium acetate, and (c) water, wherein a content of the water is 78.6 to 85.2 parts by mass relative to 100 parts by mass of the sodium acetate, and wherein a rate of crystallization is 0.6 mm/s or more, and wherein the heat storage material composition has a spontaneous crystallization initiation temperature of 20 C. or less, and wherein a content of the organic compound is, in the case of ethanol, 9.6 to 77.9 parts by mass; in the case of ethylene glycol, 32.1 to 45.5 parts by mass; in the case of propylene glycol, 9.6 to 45.5 parts by mass; and in the case of acetic acid, 9.6 to 38.6 parts by mass, relative to 100 parts by mass of the sodium acetate.

2. The heat storage material composition according to claim 1, wherein a content of the organic compound is, in the case of ethanol, 20.2 to 77.9 parts by mass; in the case of ethylene glycol, 32.1 to 45.5 parts by mass; in the case of propylene glycol, 9.6 to 45.5 parts by mass; and in the case of acetic acid, 9.6 to 26.0 parts by mass, relative to 100 parts by mass of the sodium acetate.

3. The heat storage material composition according to claim 1, wherein the heat storage material composition consists of the organic compound, the sodium acetate, and the water.

4. An auxiliary heat source, characterized by being obtainable from the heat storage material composition according to claim 1.

5. A heat supply method, characterized by using the heat storage material composition according to claim 1.

6. The heat supply method according to claim 5, wherein the method is combined with a crystallization accelerating means.

7. The heat supply method according to claim 6, wherein the crystallization accelerating means is a metal plate trigger.

Description

DESCRIPTION OF EMBODIMENTS

(1) Hereinafter, the heat storage material composition of the present invention, and the auxiliary heat source and the heat supply method using the heat storage material composition, will be described. In addition, in the present invention, A to B parts by mass means a range of from A parts by mass to B parts by mass. For example, 72.4 to 100 parts by mass indicates from 72.4 parts by mass to 100 parts by mass.

(2) <<Heat Storage Material Composition>>

(3) The heat storage material composition of the present invention at least contains at least one organic compound selected from ethanol, ethylene glycol, propylene glycol, and acetic acid; sodium acetate; and water, and the content of the water is 72.4 to 100 parts by mass, relative to 100 parts by mass of the sodium acetate.

(4) Regarding the method for obtaining the composition, there are two methods available, including: 1) a method of mixing at least one organic compound selected from ethanol, ethylene glycol, propylene glycol, and acetic acid, sodium acetate trihydrate, and water; 2) a method of mixing at least one organic compound selected from ethanol, ethylene glycol, propylene glycol, and acetic acid, anhydrous sodium acetate, and water; however, any of these methods may be used. In the case of 1), when the portion of sodium acetate of the sodium acetate trihydrate is designated as 100 parts by mass, the portion of water defined as the sum of the water and the water part of the sodium acetate trihydrate, is contained in an amount of 72.4 to 100 parts by mass. Preferably, the method 1) of using sodium acetate trihydrate is utilized. Furthermore, known additive materials may be added in accordance with the purpose, to the extent that the characteristics of the heat storage material (spontaneous crystallization initiation temperature, rate of crystallization, and amount of heat dissipation) are not markedly impaired. For example, a thickening agent may be added to the composition of the present invention to adjust the viscosity of the heat storage material, or the viscosity may be increased to obtain a gel phase.

(5) Water is preferably pure water, and the content of water is preferably 72.4 to 100 parts by mass, more preferably 78.6 to 85.2 parts by mass, and particularly preferably 81.8 parts by mass, relative to 100 parts by mass of the sodium acetate.

(6) The content of ethanol is preferably 9.6 to 77.9 parts by mass, and more preferably 20.2 to 77.9 parts by mass, relative to 100 parts by mass of the sodium acetate.

(7) The content of ethylene glycol and propylene glycol is preferably 5.6 to 45.5 parts by mass, and more preferably 9.6 to 45.5 parts by mass, relative to 100 parts by mass of the sodium acetate.

(8) The content of acetic acid is preferably 9.6 to 38.6 parts by mass, more preferably 9.6 to 26.0 parts by mass, and particularly preferably 14.7 parts by mass, relative to 100 parts by mass of the sodium acetate.

(9) The heat storage material composition of the present invention is preferably composed only of sodium acetate, water, and the organic compound, and it is more preferable that the organic compound be only any one organic compound selected from ethanol, ethylene glycol, propylene glycol, and acetic acid.

(10) The heat storage material composition of the present invention has a spontaneous crystallization initiation temperature of 20 C. or less, preferably 25 C. or less, more preferably 28 C. or less, even more preferably 30 C. or less, and particularly preferably 40 C. or less.

(11) Furthermore, the rate of crystallization is preferably 0.6 mm/s or more, more preferably 1.4 mm/s or more, and even more preferably 2.0 mm/s or more. The upper limit of the rate of crystallization is not particularly limited, but the upper limit is practically 7.0 mm/s or less.

(12) Furthermore, the amount of heat dissipation is preferably 130 kJ/kg or more, more preferably 140 kJ/kg or more, and even more preferably 150 kJ/kg or more. Meanwhile, the upper limit of the amount of heat dissipation cannot exceed 264 kJ/kg, which is the amount of heat dissipation of sodium acetate trihydrate itself, and this value is the upper limit.

(13) Herein, the spontaneous crystallization initiation temperature, the rate of crystallization, and the amount of heat dissipation can be determined as follows.

(14) (Measurement of Spontaneous Crystallization Initiation Temperature)

(15) 4 g of each sample (heat storage material) is enclosed in a sealed container, melted at 80 C., and then cooled to room temperature, to be a supercooled state. Then, a thermocouple is attached thereto, and the sealed container is placed in a thermostat chamber. The temperature of the atmosphere is lowered at a rate of, for example, about 0.7 C./min, and the sample is cooled to 40 C. The temperature change of the heat storage material is monitored with the thermocouple, and the temperature at which a rapid temperature increase caused by crystallization occurs can be determined as the spontaneous crystallization initiation temperature.

(16) (Measurement of Rate of Crystallization)

(17) 22 mL of a heat storage material and a metal plate trigger (a stainless steel plate having small slits carved thereinto) are enclosed in a sealed container with size of 60 mm160 mm3 mm, and the sealed container is left to stand at 10 C. The temperature profile of the heat storage material sample is measured with a thermocouple by operating the trigger, and at the time point when the temperature begins to rise, the crystallization initiation time instants at various measurement points is defined. The crystallization proceed time period is determined from the time difference in the crystallization initiation time instants between a distance of 100 mm, thereby the ratio of crystallization proceed distance/crystallization proceed time period is calculated, and this is designated as the rate of crystallization (mm/s).

(18) (Measurement of Amount of Heat Dissipation)

(19) Water at 25 C. is introduced into a water tank that is thermally-insulated around the periphery, and the sample used for the measurement of the rate of crystallization, which was 22 mL of the heat storage material and the metal plate trigger enclosed in a sealed container with a size of 60 mm160 mm3 mm, is placed in the water. Inside this water tank, the trigger is operated, and the temperature rise of water temperature is measured with a plurality of thermocouples, for example, twelve thermocouples. The water tank is shaken so that the water temperatures at the various measurement points become uniform, and thereby the water temperature is made uniform, and the temperature rise value is determined from an average value obtained from the twelve points. The density of water is defined as 1 g/cm.sup.3, the specific heat is defined as 4.2 J/g.Math. C., and the amount of heat received by the water is calculated from the mass of water and the temperature rise value for each measurement. The value obtained by dividing the mass of the heat storage material sample by the amount of heat is determined as the amount of heat dissipation of the heat storage material per unit mass (kJ/kg).

(20) In the heat storage material composition of the present invention, water molecules in a supercooled liquid are incorporated into the molecules of sodium acetate, and crystallization occurs. As a result, water molecules are incorporated into the crystal lattice of sodium acetate. As such, latent heat is released as crystallization occurs. However, it is presumed that since water molecules are in a state of being more easily incorporated at a low temperature, the molecules of a polar organic compound, such as ethanol, attract water molecules through hydrogen bonding, and thereby the polar organic compound suppresses crystallization of sodium acetate trihydrate.

(21) According to the present invention, as a result of adding the organic compound, the rate of crystallization becomes faster than that of the known technology involving addition of sodium thiosulfate pentahydrate described above, and the amount of heat dissipation is larger than that of the known technology involving addition of water described above.

(22) <<Auxiliary Heat Source>>

(23) The heat storage material composition of the present invention can be used as an auxiliary heat source of a heat storage system.

(24) Examples of such a heat storage system include a heat pump-type water heater, a solar heat water heater, an electric vehicle (EV) or an automobile, and floor heating.

(25) In a heat pump-type water heater, heat is stored by means of midnight power, and the heat can be used the next day. Also, since heat can be stored at a high heat storage density, size reduction of the heated water storage tank is made possible.

(26) In a solar heat water heater, solar heat is stored in the daytime, and hot water supply can be used in the night.

(27) In an electric vehicle (EV) or an automobile, waste heat of the engine, motor, heating water after parking, and the like can be stored, or can be used in heating by energization of a heater from a power supply for charging, thermal insulation of batteries, engine warming up, thermal insulation of lubricant oil, and thermal insulation of washer liquid.

(28) In floor heating, heat storage using midnight power is made possible.

(29) Also, the heat storage material may also be utilized as a heat storage material-included package unit.

(30) Examples thereof include a thermal battery, a heat source for emergency, and a disposable heating pocket warmer.

(31) In a thermal battery, waste heat generated in plants, data center, stores, and the like is packaged, and the waste heat can be utilized at a place distant from a heat source by operating a trigger.

(32) A heat source for emergency and a disposable heating pocket warmer can be utilized as heat sources in a state or place lacking electric power, by combining the heat source or the pocket warmer with a trigger that can be manually operated.

(33) <<Heat Supply Method>>

(34) A heat supply method can be provided, as a heat storage system or a heat storage material-included package unit such as described above, by using the heat storage material composition of the present invention.

(35) Particularly, in order to immediately supply heat utilization at an arbitrary time point, it is preferable to combine the heat storage material composition with a crystallization acceleration means (e.g. a supercooling relieving means, a trigger device).

(36) Examples of the crystallization acceleration means include a seed crystal, a metal plate (a metal plate flip), voltage application, local cooling, and application of vibration, and for example, the means described in JP-A-2011-75050 may be used, which are also preferable for the present invention. Among these, it is preferable to use a seed crystal or a metal plate (a metal plate flip), and a metal plate (a metal plate flip) is particularly preferred. Such a metal plate is specifically a stainless steel disk with diameter 20 mm and thickness 0.2 mm, which is provided with cracks each with length of 3 mm at 12 sites, and is bent at the center to a height of about 1 mm. The metal plate is not intended to be limited to this shape, and for example, the shapes described in the specification of U.S. Pat. No. 4,379,448 may also be used.

(37) The heat supply apparatus is applied to the apparatuses described in, for example, JP-A-2011-75050, JP-A-2010-196508, JP-A-2009-264155, JP-A-2009-236433, JP-A-63-105219, JP-A-63-68418, JP-A-62-172190, JP-A-61-22194, Japanese Patent Application No. 2012-061476, and Japanese Patent Application No. 2012-061477.

Examples

(38) The present invention will be described in more detail based on examples given below, but the invention is not meant to be limited by these.

Example 1

(39) Various heat storage material samples each having a total amount of heat storage material of 4 g were produced with the heat storage material compositions of Table 1.

(40) The following items of these samples were measured.

(41) (Measurement of Spontaneous Crystallization Initiation Temperature)

(42) 4 g of each sample (heat storage material) was enclosed in a sealed container, melted at 80 C., and then cooled to room temperature, to be a supercooled state. Then, a thermocouple was attached thereto, and the sealed container was placed in a thermal chamber. The temperature of the atmosphere was lowered at a rate of, for example, about 0.7 C./min, and the sample was cooled to 40 C. The temperature change of the heat storage material was monitored with the thermocouple, and the temperature at which a rapid temperature rise caused by crystallization occurred was determined as the spontaneous crystallization initiation temperature.

(43) (Measurement of Rate of Crystallization)

(44) 22 mL of a heat storage material and a metal plate trigger (a stainless steel disk with diameter 20 mm and thickness 0.2 mm, provided with cracks each having a length of 3 mm at twelve sites, and bent at the center to a height of about 1 mm) were enclosed in a sealed container with a size of 60 mm160 mm3 mm, and the sealed container was left to stand at 10 C. The temperature profile of the heat storage material sample was measured with a thermocouple by operating the trigger, and at the time point when the temperature began to rise, the crystallization initiation time instants at various measurement points was defined. The crystallization proceed time period was determined from the time difference in the crystallization initiation time instants between a distance of 100 mm, thereby the ratio of crystallization proceed distance/crystallization proceed time period was calculated, and this is designated as the rate of crystallization (mm/s).

(45) (Measurement of Amount of Heat Dissipation)

(46) Water at 25 C. was introduced into a water tank that was thermally-insulated around the periphery, and the sample used for the measurement of the rate of crystallization, which was 22 mL of the heat storage material and the metal plate trigger enclosed in the sealed container with a size of 60 mm160 mm3 mm, was placed in the water. Inside this water tank, the trigger was operated, and the temperature rise of water temperature was measured with twelve thermocouples. The water tank was shaken so that the water temperatures at the various measurement points became uniform, and thereby the water temperature was made uniform, and the temperature rise value was determined from an average value obtained from the twelve points. The density of water is defined as 1 g/cm.sup.3, the specific heat of water is defined as 4.2 J/g.Math. C., and the amount of heat received by the water was calculated from the mass of water and the temperature rise value for each measurement. The value obtained by dividing the mass of the heat storage material sample by the amount of heat was determined as the amount of heat dissipation of the heat storage material per unit mass (kJ/kg).

(47) Herein, Sample Nos. 1 to 3 are Comparative examples, and among these, Sample No. 2 is a sample described in JP-A-4-324092.

(48) The results thus obtained are summarized in Table 1.

(49) TABLE-US-00001 TABLE 1 Blending amounts of Spontaneous composition components (mass parts) crystallization Amount Blending Blending Blending initiation Rate of of heat Sample amount of amount of amount of temperature crystallization dissipation No. sodium acetate water additive [ C.] [mm/s] [kJ/kg] Remarks 1 100 81.8 14 6.3 163 Comparative example 2 100 115.7 <40 2.9 94 Comparative example 3 100 86.0 Sodium thiosulfate <40 0.3 140 Comparative 35.2 example 4 100 81.8 Ethanol <40 1.4 140 This 45.5 invention 5 100 81.8 Propylene glycol 33 2.3 153 This 9.6 invention 6 100 81.8 Ethylene glycol 29 2.0 139 This 9.6 invention 7 100 81.8 Acetic acid 32 2.4 146 This 14.7 invention 8 100 70.0 Ethanol 17 1.1 105 Comparative 45.0 example 9 100 105.0 Ethanol 16 1.0 145 Comparative 45.5 example

(50) From Table 1, in regard to Sample Nos. 1 to 3, which are prior art techniques, shown as comparative examples, Sample 1 exhibited a fast rate of crystallization and an amount of heat dissipation at a satisfactory level; however, the spontaneous crystallization initiation temperature was 14 C., which was higher than 20 C. In Sample No. 2, the spontaneous crystallization initiation temperature was 40 C. or less, and the rate of crystallization was at a satisfactory level; however, the amount of heat dissipation was as small as 94 kJ/kg. Furthermore, in Sample No. 3, the spontaneous crystallization initiation temperature was 40 C. or less, and the amount of heat dissipation was 140 kJ/kg, which was not so small; however, the rate of crystallization was 0.30 mm/s.

(51) On the contrary, in Sample Nos. 4 to 7 according to the present invention, the spontaneous crystallization initiation temperatures were all low, such as about 20 C. or less, and the rate of crystallization and the amount of heat dissipation each were also at a satisfactory level.

(52) In Sample Nos. 8 and 9 of comparative examples, the spontaneous crystallization initiation temperature was higher than 20 C.

Example 2

(53) The dependency on the amount of addition of ethanol was evaluated.

(54) The thus-obtained results are shown in Table 2.

(55) TABLE-US-00002 TABLE 2 Blending amounts of Spontaneous composition components (mass parts) crystallization Blending Blending Blending initiation Sample amount of amount of amount of temperature No. sodium acetate water ethanol C. 101 100 81.8 1.8 21 102 100 81.8 9.6 26 103 100 81.8 20.2 35 104 100 81.8 32.1 <40 105 100 81.8 45.5 <40 106 100 81.8 77.9 <40 107 100 81.8 80.1 <40

(56) Sample 105 is the sample equivalent to Sample 4 of Table 1.

(57) Herein, the rate of crystallization of each of Sample Nos. 102, 104, and 105 was 2.9 mm/s, 1.6 mm/s, and 1.4 mm/s, respectively.

(58) In Sample Nos. 102 to 107, the spontaneous crystallization initiation temperature was 25 C. or less.

(59) In Sample Nos. 101 to 106, the rate of crystallization was 0.6 mm/sec or more, and the amount of heat dissipation was 130 kJ/kg or more.

(60) In Sample No. 107, the rate of crystallization was less than 0.6 mm/sec, and the amount of heat dissipation was less than 130 kJ/kg.

Example 3

(61) The dependency on the amount of addition of ethylene glycol was evaluated in the same manner as in Example 2.

(62) The thus-obtained results are shown in Table 3.

(63) TABLE-US-00003 TABLE 3 Blending amounts of Spontaneous composition components (mass parts) crystallization Blending Blending Blending initiation Sample amount of amount of amount of temperature No. sodium acetate water ethylene glycol [ C.] 201 100 81.8 1.8 17 202 100 81.8 5.6 28 203 100 81.8 9.6 29 204 100 81.8 13.7 36 205 100 81.8 20.2 <40 206 100 81.8 32.1 <40 207 100 81.8 45.5 <40 208 100 81.8 47.8 <40

(64) In Sample Nos. 202 to 208, the spontaneous crystallization initiation temperature was 25 C. or less. In Sample No. 201, the spontaneous crystallization initiation temperature was higher than 25 C.

(65) In Sample Nos. 201 to 207, the rate of crystallization was 0.6 mm/sec or more. In Sample No. 208, the rate of crystallization was less than 0.6 mm/sec.

(66) In Sample Nos. 201 to 208, the amount of heat dissipation was 130 kJ/kg or more.

Example 4

(67) The dependency on the amount of addition of propylene glycol was evaluated in the same manner as in Example 2.

(68) The thus-obtained results are shown in Table 4.

(69) TABLE-US-00004 TABLE 4 Blending amounts of Spontaneous composition components (mass parts) crystallization Blending Blending Blending initiation Sample amount of amount of amount of temperature No. sodium acetate water propylene glycol [ C.] 301 100 81.8 1.8 21 302 100 81.8 5.6 20 303 100 81.8 9.6 32 304 100 81.8 13.7 29 305 100 81.8 20.2 28 306 100 81.8 32.1 <40 307 100 81.8 45.5 <40 308 100 81.8 47.5 <40

(70) In Sample Nos. 303 to 308, the spontaneous crystallization initiation temperature was 25 C. or less.

(71) In Sample Nos. 301 to 307, the rate of crystallization was 0.6 mm/sec or more. In Sample No. 308, the rate of crystallization was less than 0.6 mm/sec.

(72) In Sample Nos. 301 to 308, the amount of heat dissipation was 130 kJ/kg or more.

Example 5

(73) The dependency on the amount of addition of acetic acid was evaluated in the same manner as in Example 2.

(74) The thus-obtained results are shown in Table 5.

(75) TABLE-US-00005 TABLE 5 Blending amounts of Spontaneous composition components (mass parts) crystallization Blending Blending Blending initiation Sample amount of amount of amount of temperature No. sodium acetate water acetic acid [ C.] 401 100 81.8 4.7 20 402 100 81.8 9.6 26 403 100 81.8 14.7 32 404 100 81.8 26.0 26 405 100 81.8 38.6 25 406 100 81.8 40.3 23

(76) In Sample Nos. 402 to 405, the spontaneous crystallization initiation temperature was 25 C. or less. In Sample Nos. 401 and 406, the spontaneous crystallization initiation temperature was higher than 25 C.

(77) As described above, according to the present invention, a heat storage material composition, which is high in thermal energy storage stability at least at a temperature near 20 C.; which retains the energy of a latent heat portion generated by a supercooled state, even at room temperature; and which immediately enables heat utilization at any arbitrary time point, can be obtained. Thereby, an auxiliary heat source and a heat supply method, each using the heat storage material composition, can be provided.

(78) Having described our invention as related to the present embodiments, it is our intention that the invention not be limited by any of the details of the description, unless otherwise specified, but rather be construed broadly within its spirit and scope as set out in the accompanying claims.