JP2007333329A - Heat storage device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that the heat stored in a heat storage part can not be used at high efficiency, when the heat at predetermined temperature (for example, 42°C) or higher is tapped for hot water supply usage. <P>SOLUTION: This heat storage device is provided with a heat storage part laminating a plurality of heat storage vessels 1 filled with heat storage material of main component of latent heat heat storage material, a first heat exchange part 4 of a heat storage part and a heating medium heating the heat storage part, and a second heat exchange part 5 of a heat storage part and a heat absorbing medium absorbing heat from the heat storage part. Temperature of the heat storage material of the heat storage vessel 1 close to an inlet part of heat absorbing medium at a time of supercooling is lower than temperature of the heat storage material of the heat storage vessel 1 close to an outlet part of heat absorbing medium at a time of supercooling. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heat storage device that can use heat stored in a heat storage unit with high efficiency.

  2. Description of the Related Art Conventionally, as disclosed in Patent Document 1, for example, a heat storage device is known in which heat of a heat source unit is temporarily stored in a heat storage unit and the heat of the heat storage unit is supplied to a user side by a heat medium. This heat storage device is provided with a heat exchanging part in a heat accumulating part filled with a heat accumulating material, passing water as a heat medium through a heat transfer tube of the heat exchanging part, and supplying water heated by the heat medium to the use side It is used for vessels. Moreover, as a heat storage material of the heat storage unit, in order to secure a large amount of heat storage, a material using a latent heat storage material has been well studied. Furthermore, sodium acetate trihydrate has been well studied as a latent heat storage material for hot water supply.

When sodium acetate trihydrate is used, for example, as disclosed in Patent Document 2, sodium carbonate monohydrate, sodium pyrophosphate decahydrate, barium bromate monohydrate , Calcium sulfate dihydrate, sodium dihydrogen pyrophosphate hexahydrate, ferric acetate, ferrous chloride, ferric chloride, calcium chloride, calcium bromide, cupric chloride, calcium tartrate, It is common to add an anti-cooling agent such as disodium hydrogen phosphate / 12 hydrate, trisodium phosphate / 12 hydrate, and fluoride.
JP 2001-207163 A JP-A-8-60141

  However, when extracting heat at a predetermined temperature (for example, 42 ° C.) or more in hot water supply applications, a large amount of heat remains in the upper part of the heat storage unit, so the amount of heat extracted decreases and the heat stored in the heat storage unit is highly efficient. There was a problem that it could not be used.

  An object of the present invention is to provide a heat storage device that solves the above-described problems.

In order to solve the problems described above, in the heat storage device of the present invention, a heat storage unit having a plurality of heat storage containers including a latent heat storage material,
A first heat exchanging portion through which the heating medium flows so that the heating medium for heating the heat storage material and the heat storage material exchange heat;
The heat absorption medium circulates so that the heat absorption medium that absorbs heat from the heat storage material and the heat storage material exchange heat, and includes a second heat exchange section having an inlet portion and an outlet portion of the heat absorption medium,
The temperature at the time of supercooling of the heat storage material of the heat storage container near the inlet portion of the heat absorption medium is lower than the temperature at the time of supercooling of the heat storage material of the heat storage container near the outlet portion of the heat absorption medium.

  In a more desirable configuration, the temperature at the time of supercooling the heat storage material of the heat storage container close to the inlet portion of the heat absorbing medium is 20 ° C. or less.

Moreover, in another heat storage device of the present invention, a heat storage unit having a plurality of heat storage containers including a latent heat storage material and a supercooling inhibitor,
A first heat exchanging portion through which the heating medium flows so that the heating medium for heating the heat storage material and the heat storage material exchange heat;
The heat absorption medium circulates so that the heat absorption medium that absorbs heat from the heat storage material and the heat storage material exchange heat, and includes a second heat exchange section having an inlet portion and an outlet portion of the heat absorption medium,
The concentration of the supercooling inhibitor in the heat storage container near the inlet portion of the heat absorbing medium is lower than the concentration of the supercooling inhibitor in the heat storage container near the outlet portion of the heat absorbing medium.

  More preferably, the heat absorbing medium is water for hot water supply, and the latent heat storage material in the heat storage material is sodium acetate trihydrate.

  Since the heat storage device of the present invention can increase the amount of heat extracted from the heat storage material arranged at the top when taking out heat at a predetermined temperature (for example, 42 ° C.) or more for hot water supply, the heat stored in the heat storage unit Can be used with high efficiency.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, detailed descriptions of known means that have been widely employed are omitted.

(Embodiment 1)
FIG. 1 is a configuration diagram of a heat storage device according to the first embodiment. The heat storage container 1 is configured to be able to be filled with a heat storage material at six locations. The first heat storage material 2 is filled at five locations from the top, and the second heat storage material 3 is filled at the bottom. Further, through the wall of the heat storage container 1, the first heat exchange unit 4 that performs heat exchange between the heating medium and the heat storage material is performed on one side, and the second that performs heat exchange between the heat absorption medium and the heat storage material on the other side. A heat exchange unit 5 is provided. Further, a heat pump cycle including a compressor 6, a radiator 7, an expansion valve 8, and an evaporator 9 is provided as a heat source unit for heating the heating medium.

  The material of the heat storage container 1 is copper, and the surface on the side where the heat storage material is filled is plated with tin. The first heat exchange unit 4 and the second heat exchange unit 5 are both box-shaped structures surrounded by copper plates. Moreover, water for hot water supply is used as the heat absorption medium. In addition, carbon dioxide suitable for hot water supply is used as a refrigerant for the heat pump cycle. Moreover, the main component of both the first heat storage material 2 and the second heat storage material 3 is sodium acetate trihydrate, which is a supercooling inhibitor and contains trisodium phosphate 12 hydrate. The concentration of the supercooling inhibitor in the first heat storage material 2 is lower than the concentration of the supercooling inhibitor in the second heat storage material 3.

  Next, operation | movement of the thermal storage apparatus concerning this Embodiment 1 is demonstrated. During heat storage, the heating medium flows in the direction indicated by the solid arrow A. In the radiator 7, heat exchange is performed between the high-temperature and high-pressure refrigerant and the heating medium, and the heated heating medium flows in from the upper side of the first heat exchange unit 4, and the first heat storage material 2. Then, after heating in the order of the second heat storage material 3, it flows out from the lower side and flows as a cycle in which heat exchange with the refrigerant is performed again. Further, at the time of heat dissipation, the heat absorption medium flows in the direction indicated by the broken-line arrow B, the heat absorption medium flows in from the lower side of the second heat exchange unit 5, and the second heat storage material 3 and the first heat storage material 2 After absorbing heat sequentially, it flows out from the upper side and is used for applications such as hot water supply.

In FIG. 2, the influence with respect to the supercooling cancellation | release temperature by the weight concentration of the supercooling inhibitor added to the latent heat storage material is shown. This is the result of changing the concentration of the supercooling inhibitor using sodium sulfate decahydrate as the latent heat storage material and sodium tetraborate decahydrate as the supercooling inhibitor. In FIG. 2, when the weight concentration of the supercooling inhibitor is 0.22% or more, the supercooling release temperature is substantially constant at about 25 ° C., and when the weight concentration of the supercooling inhibitor is 0.1% or less, The cooling release temperature is rapidly decreasing. Since the relationship between the weight concentration of the supercooling inhibitor and the supercooling release temperature varies depending on various conditions such as the size of the heat storage container, quantitative discussion is difficult, but nucleation starts from the supercooling inhibitor. Since it occurs with a certain probability as a function of temperature, qualitatively, it is clear that when the weight concentration of the supercooling inhibitor is low, the supercooling release temperature tends to be low. This tendency is the same for sodium acetate trihydrate. In FIG. 3, sodium acetate trihydrate is used for the first heat storage material 2 and the second heat storage material 3, and the concentration of the supercooling inhibitor is increased. The time change (analysis result) of each part temperature at the time of heat dissipation in the comparative example made equal is shown. Here, the conditions are: the thickness of the first heat storage material 2 and the second heat storage material 3: 6 mm, the thickness of the second heat exchange part 5: 2 mm, the flow rate of the heat absorption medium: 0.006 m / sec, The height is 900 mm, the temperature at the start of heat radiation is 80 ° C., and the inlet temperature of the heat absorbing medium to the second heat exchange part is 9 ° C. As shown in the figure, the temperature is lowered by radiating heat from the second heat storage material 3 arranged at the lower part to the heat absorption medium, and the first heat storage material 2 arranged at the upper part gradually radiates heat to the heat absorption medium as well. The temperature decreases. At this time, the first heat storage material 2 and the second heat storage material 3 start to solidify without causing overcooling.

  FIG. 4 shows a time change (analysis result) of each part temperature at the time of heat dissipation in Embodiment 1 of the present invention. Here, the conditions are the same as in FIG. As shown in FIG. 4, the temperature of the second heat storage material 3 disposed in the lower part is radiated to the heat absorption medium and the temperature is lowered, and the first heat storage material 2 disposed in the upper part gradually radiates to the heat absorption medium as well. Temperature decreases. At this time, the second heat storage material 3 starts to solidify after being supercooled by about 40 ° C. from the melting point of 58 ° C.

  In order to clarify the effect of the first embodiment of the present invention on the comparative example, FIG. 5 shows the influence on the hot water discharge time at the hot water supply temperature of 42 ° C. or higher due to the temperature at the time of supercooling in the first embodiment of the present invention. No overcooling of the heat storage material 2, analysis results). FIG. 5 shows the prevention of overcooling of the second heat storage material 3 on the basis of a comparative example in which the concentrations of the supercooling prevention agents of the first heat storage material 2 and the second heat storage material 3 are equal (both are not overcooled). In the case where the concentration of the material is lowered and only the second heat storage material 3 is supercooled, the elongating rate of the tapping time is expressed with respect to the second heat storage material 3. Here, the hot water efficiency when both the first heat storage material 2 and the second heat storage material 3 are not supercooled (= the amount of discharged heat / the maximum heat capacity of the first heat storage material 2 and the second heat storage material 3) is as follows. 85%. Thus, when the temperature at the time of supercooling of the 2nd heat storage material 3 becomes low, the elongation rate of the tapping time tends to become large, and the temperature at the time of supercooling of the 2nd heat storage material 3 is 20 degrees C or less especially. This tendency becomes remarkable.

  In order to clarify the reason, FIG. 6 shows a comparative example (both the first heat storage material 2 and the second heat storage material 3 are not supercooled) and the first embodiment of the present invention (supercooling degree 40 deg.). The amount of heat retained by the first heat storage material 2 and the second heat storage material 3 (analysis result) when the hot water supply temperature (the temperature at which the endothermic medium is taken out) is reduced to 42 ° C. during heat dissipation in FIG. Thus, in Embodiment 1 of this invention, compared with a comparative example, the heat storage amount of the 1st heat storage material 2 arrange | positioned at the upper part has fallen, the taking-out heat amount increased, and it stored in the heat storage apparatus. Heat can be used with high efficiency. This is considered to be because the heat absorbing medium absorbs a larger amount of heat from the first heat storage material 2 while the second heat storage material 3 is undercooling.

  FIG. 7 shows the influence of the temperature at the time of supercooling in the first embodiment of the present invention on the hot water discharge time at a hot water supply temperature of 42 ° C. or higher (the first heat storage material 2 is supercooled and the analysis result). FIG. 7 shows the prevention of overcooling of the second heat storage material 3 on the basis of a comparative example in which the concentrations of the anticooling agents of the first heat storage material 2 and the second heat storage material 3 are equal (both are overcooled). About the case where the density | concentration of material is made low and the supercooling degree of the 2nd thermal storage material 3 is enlarged, the elongation rate of the hot water discharge time is represented with respect to the comparative example. From FIG. 5 and FIG. 7, when the temperature at the time of supercooling of the 1st heat storage material 2 is higher than a tapping temperature, the density | concentration of the supercooling inhibitor of the 2nd heat storage material 3 was made higher than the 1st heat storage material 2. There is an increase in the hot spring time. In addition, if the temperature at the time of supercooling of the first heat storage material 2 is equal to or higher than the tapping temperature, this tendency becomes significant at a temperature of 20 ° C. or less at the time of supercooling the second heat storage material 3.

  In addition, in Embodiment 1 of this invention, although the heat storage container 1, the 1st heat exchange part 4, and the 2nd heat exchange part 5 are each arrange | positioned one each, as shown in FIG. It is good also as a structure which laminated | stacked the thermal storage container 1, the 1st heat exchange part 4, and the 2nd heat exchange part 5 in the horizontal direction, and the effect similar to the structure of FIG. 1 is acquired.

  Moreover, although the heating medium which heat-exchanged with the refrigerant | coolant with the condenser 7 of the heat pump cycle was flowed into the 1st heat exchange part 4 at the time of heat storage, as shown in FIG. It is good also as a structure which shares the exchange part 4, makes a refrigerant | coolant flow directly into the 1st heat exchange part 4, and heats the 1st heat storage material 2 and the 2nd heat storage material 3, and is the same as the structure of FIG. An effect is obtained.

  In the first embodiment, the flow direction of the heating medium and the heat storage medium is the vertical direction. However, as shown in FIG. 9, the partition plate 11 may be provided and the flow direction may be the horizontal direction. The same effect as the configuration can be obtained.

  Further, in both the first heat storage material 2 and the second heat storage material 3, trisodium phosphate dodecahydrate is added to sodium acetate trihydrate. However, when used for applications such as heating, it is sufficient that the melting point of the latent heat storage material is lower than 58 ° C.

  As the supercooling preventive agent, trisodium phosphate 12 hydrate is used, but sodium carbonate monohydrate, sodium pyrophosphate decahydrate, barium bromate monohydrate, sulfuric acid Calcium dihydrate, sodium dihydrogen pyrophosphate hexahydrate, ferric acetate, ferrous chloride, ferric chloride, calcium chloride, calcium bromide, cupric chloride, calcium tartrate, hydrogen phosphate Fluoride such as disodium · 12 hydrate and lithium fluoride, sodium tetraborate · hydrate, sodium chloride, sodium sulfate and the like may be used. Further, a thickener may be added in addition to the latent heat storage material and the supercooling preventive agent.

  Furthermore, it is set as the structure which can be filled with the heat storage container 1 in six places, and the 2nd heat storage material 3 with low weight concentration of a supercooling prevention agent is filled in one place among them, but the flow rate of a heat absorption medium, the 1st Since it changes with conditions, such as the thickness of the thermal storage material 2 and the 2nd thermal storage material 3, the thickness of the 2nd heat exchange part 5, the height of a thermal storage apparatus, it is not limited to this structure and obtains optimal performance. As such, it can be arbitrarily selected. Moreover, the weight concentration of the supercooling preventive agent is not limited to two types. The weight concentration of the supercooling preventive agent in the heat storage material arranged at the lower portion and the weight concentration of the supercooling preventive agent in the heat storage material arranged at the upper portion. You may leave a gradient between

  The heat storage device according to the present invention and the heat storage device using the heat storage device can be developed for household water heater applications, but are not necessarily limited to this, for household heating applications, industrial waste heat storage, etc. Can also be deployed.

Configuration diagram of heat storage device in Embodiment 1 of the present invention The figure showing the influence on the supercooling release temperature by the weight concentration of the supercooling inhibitor added to the latent heat storage material The figure showing the time change (analysis result) of each part temperature at the time of heat dissipation in the comparative example which used sodium acetate trihydrate for the 1st heat storage material 2 and the 2nd heat storage material 3. The figure showing the time change (analysis result) of each part temperature at the time of heat dissipation in Embodiment 1 of this invention The figure showing the influence (no overcooling of the 1st heat storage material 2, an analysis result) with respect to the hot water time in the hot water supply temperature of 42 degreeC or more by the temperature at the time of supercooling in Embodiment 1 of this invention Heat quantity (analysis result) of the first heat storage material 2 and the second heat storage material 3 at the time when the hot water supply temperature is reduced to 42 ° C. during heat radiation in the comparative example and Embodiment 1 of the present invention (supercooling degree 40 deg.) ) The figure showing the influence (with the 1st heat storage material 2 being overcooled and an analysis result) with respect to the hot water discharge time in the hot water supply temperature of 42 degreeC or more by the temperature at the time of supercooling in Embodiment 1 of this invention Configuration diagram of heat storage device improved from Embodiment 1 of the present invention Configuration diagram of heat storage device improved from Embodiment 1 of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat storage container 2 1st heat storage material 3 2nd heat storage material 4 1st heat exchange part 5 2nd heat exchange part 6 Compressor 7 Radiator 8 Expansion valve 9 Evaporator 10 Common heat exchange part 11 Partition plate

Claims (4)

A heat storage section having a plurality of heat storage containers including a latent heat storage material;
A first heat exchanging portion through which the heating medium flows so that the heating medium for heating the heat storage material and the heat storage material exchange heat;
The heat absorption medium circulates so that the heat absorption medium that absorbs heat from the heat storage material and the heat storage material exchange heat, and includes a second heat exchange section having an inlet portion and an outlet portion of the heat absorption medium,
The heat storage device in which the temperature at the time of supercooling of the heat storage material of the heat storage container near the inlet portion of the heat absorption medium is lower than the temperature at the time of supercooling of the heat storage material of the heat storage container near the outlet portion of the heat absorption medium. A heat storage section having a plurality of heat storage containers including a latent heat storage material and a supercooling inhibitor;
A first heat exchanging portion through which the heating medium flows so that the heating medium for heating the heat storage material and the heat storage material exchange heat;
The heat absorption medium circulates so that the heat absorption medium that absorbs heat from the heat storage material and the heat storage material exchange heat, and includes a second heat exchange section having an inlet portion and an outlet portion of the heat absorption medium,
A heat storage device in which the concentration of the supercooling inhibitor in the heat storage container near the inlet portion of the heat absorbing medium is lower than the concentration of the supercooling inhibitor in the heat storage container near the outlet portion of the heat absorbing medium.   The heat storage device according to claim 1 or 2, wherein the heat absorption medium is water, and the latent heat storage material in the heat storage material is sodium acetate trihydrate. 2. The heat storage device according to claim 1, wherein the temperature of the heat storage material in the heat storage container close to the inlet portion of the heat absorption medium is 20 ° C. or less during supercooling.

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