JP6201834B2 - Heat storage device - Google Patents

Description

  The present invention relates to a heat storage device including a heat storage material capable of storing and radiating heat.

  Conventionally, a heat storage device has been disclosed in which a heat storage material is provided in an exhaust pipe of a vehicle to store exhaust heat during traveling, and heat that is stored at the next start is released to heat the catalyst (for example, Patent Document 1). In this heat storage device, a single type of heat storage material is employed, and heat at a uniform temperature is generated during heat dissipation using high-temperature exhaust upstream of the exhaust pipe or low-temperature exhaust downstream of the exhaust pipe.

JP 2011-106355 A

  In the heat storage device described in Patent Document 1, the heat storage temperature is set in accordance with the most downstream side of the exhaust flow in the heat storage device, that is, the portion where the exhaust temperature is lowest. For this reason, on the upstream side of the exhaust flow, the high-temperature and high-quality energy of the exhaust gas is used to store low-temperature and low-quality energy, and as a result, the quality of the heat energy that can be effectively used is lowered. There is.

  An object of this invention is to provide the thermal storage apparatus which can suppress the fall of the quality of the thermal energy at the time of thermal storage in view of the said point.

In order to achieve the above object, the invention according to claim 1 includes a heat storage unit (10) having a heat storage unit (2) for storing a heat storage material (1) for storing warm heat, and the outside of the heat storage unit (2) is provided. heat storage fluid and the heat storage material with are configured to exchange heat is performed between the (1), and radiating modes providing a heat stored in the heat storage material (1) to the fluid, the heat possessed by the fluid flowing In the heat storage device configured to be able to switch between the heat storage modes for storing heat in the material (1), a portion of the heat storage section (2) where the temperature of the fluid becomes the first reference temperature determined in the heat storage mode is the first portion. (21), and when the part where the temperature of the fluid becomes the second reference temperature lower than the first reference temperature in the heat storage mode is the second part (22), the heat storage unit (2) The heat storage temperature of the first part (21) is stored in the second part (22). To be higher than the temperature, a plurality kinds of heat storage material (1) is provided, heat storage unit (2), the more sites Exergy lower heat storage material (1) to the heat radiation mode, heat transfer area of the fluid It is characterized by being configured to be large .

According to this, in the heat storage part (2), the heat storage temperature of the first part (21) having a high fluid temperature in the heat storage mode is higher than the heat storage temperature of the second part (22) having a low fluid temperature in the heat storage mode. By providing a plurality of types of heat storage material (1) so as to be high, heat can be stored in the heat storage material (1) having a heat storage temperature corresponding to the temperature of the fluid as the heat source . For this reason, since heat can be stored in the heat storage material (1) in a state of high exergy, it is possible to suppress deterioration in the quality of thermal energy during heat storage.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

It is a schematic perspective view which shows the thermal storage apparatus which concerns on 1st Embodiment. It is a schematic sectional drawing which shows the thermal storage apparatus which concerns on 1st Embodiment. It is a characteristic view which shows the relationship between the exhaust temperature in the thermal storage mode and the thermal storage temperature of a thermal storage material with respect to the position of the exhaust flow direction in a thermal storage part. It is a characteristic view which shows the relationship between the thermal storage temperature and thermal storage density of a thermal storage material. The relationship between the heat storage temperature of the heat storage material, the exhaust temperature in the heat dissipation mode in the heat storage device according to the first embodiment, and the exhaust temperature in the heat dissipation mode in the heat storage device according to the comparative example with respect to the position in the exhaust flow direction in the heat storage unit is shown. FIG. It is a schematic sectional drawing which shows the heat storage apparatus which concerns on 2nd Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
The heat storage device of the first embodiment stores heat stored in the exhaust of the internal combustion engine (engine) when the vehicle is traveling, and uses the stored heat at the next start for exhaust warming. The heat storage device of the present embodiment is configured to be switchable between a heat release mode in which heat stored in a heat storage material described later is supplied to exhaust (heating target) and a heat storage mode in which the heat (heat source) is stored in the heat storage material Has been.

  As shown in FIGS. 1 and 2, the heat storage device includes a heat storage unit 10 having a heat storage unit 2 that houses a heat storage material 1 that stores warm heat. The heat accumulator 10 is connected to an exhaust pipe 20 through which engine exhaust flows. Specifically, the heat accumulator 10 is formed in a cylindrical shape. The heat accumulator 10 and the exhaust pipe 20 are disposed on the same axis. That is, the tube axis of the heat accumulator 10 and the tube axis of the exhaust pipe 20 coincide.

  As shown in FIG. 2, an exhaust passage 4 through which exhaust flows is formed inside the regenerator 10. The exhaust passage 4 extends in the cylinder axis direction of the regenerator 10 and is disposed at a substantially central portion of the regenerator 10. The exhaust passage 4 is connected to the exhaust pipe 20 at each end of the heat accumulator 10 in the cylinder axis direction. Thereby, the exhaust passage 4 communicates with the exhaust pipe 20.

  The heat storage unit 2 is provided on the outer peripheral side of the exhaust passage 4 in the heat storage unit 10. Specifically, the heat storage unit 2 is formed in a ring shape (annular shape) so as to go around the outer periphery of the exhaust passage 4. Moreover, the heat storage part 2 is comprised so that the partition wall 5 and the thermal storage material 1 which form (compartment) the exhaust passage 4 may contact thermally. Thus, heat is exchanged between the exhaust gas flowing outside the heat storage unit 2 and the heat storage material 1.

  Hereinafter, the detailed structure of the heat storage part 2 in this embodiment is demonstrated.

  Here, FIG. 3 shows the relationship between the exhaust temperature in the heat storage mode and the heat storage temperature of the heat storage material 1 (temperature that can be taken out from the heat storage material 1 after a predetermined time has elapsed since the heat storage) with respect to the position in the exhaust flow direction in the heat storage unit 2. In FIG. 3, the solid line indicates the heat storage temperature of the heat storage material 1, and the broken line indicates the exhaust temperature. As shown by a broken line in FIG. 3, in the heat storage mode, in the heat storage unit 2, the exhaust gas temperature becomes lower from the exhaust inlet 21 to the outlet 22.

  Here, in the heat storage unit 2, a portion where the exhaust temperature becomes a first reference temperature determined in the heat storage mode is set as a first portion, and the exhaust gas temperature is lower than the first reference temperature in the heat storage mode. The part which becomes becomes the second part. As shown in FIG. 2, the heat storage unit 2 has a plurality of types (five types in this example) having different heat storage temperatures so that the heat storage temperature of the first part is higher than the heat storage temperature of the second part in the heat storage mode. The heat storage material 1 is provided. In the heat storage part 2, the 1st site | part is located in an exhaust flow upstream rather than the 2nd site | part. In this embodiment, the inlet part 21 comprises the 1st site | part, and the exit part 22 comprises the 2nd site | part.

  More specifically, a plurality of types of heat storage materials 1 are provided in the heat storage unit 2 so that the heat storage temperature decreases as the exhaust gas temperature decreases in the heat storage mode. In the present embodiment, as shown by the solid line in FIG. 3, in the heat storage mode, the heat storage temperature of the heat storage material 1 gradually decreases stepwise as the exhaust gas temperature decreases.

  Returning to FIG. 2, a plurality of partition members 6 formed in a plate shape are disposed in the heat storage unit 2 at intervals. Each of the plurality of partition members 6 extends in a direction orthogonal to the cylinder axis direction, and partitions the heat storage unit 2 into a plurality of spaces. And each of the multiple types of heat storage materials 1 can be fixed at a predetermined reference position by filling the spaces partitioned by the partition members 6 with different types of heat storage materials 1. Therefore, the partition member 6 corresponds to the fixing means of the present invention. In this example, the partition member 6 is made of metal or resin.

  The heat storage unit 2 is configured such that the heat transfer area with the exhaust becomes larger as the portion of the heat storage material 1 having lower exergy in the heat release mode is lower. That is, the heat storage unit 2 is configured such that the heat transfer area with the exhaust becomes larger as the heat storage temperature of the heat storage material 1 is lower. In this embodiment, the space | interval of the adjacent partition members 6 is large, so that the heat storage temperature of the heat storage material 1 is low.

  The heat accumulator 10 is configured such that the exhaust gas flows from a portion where the exergy of the heat storage material 1 is high to a portion where the exergy is low in the heat dissipation mode. That is, the heat accumulator 10 is configured such that the exhaust gas flows from a portion where the heat storage temperature of the heat storage material 1 is high toward a low portion during the heat dissipation mode. In the present embodiment, the exhaust flow directions are equal in the heat storage mode and the heat dissipation mode.

  By the way, as the heat storage material 1, an adsorbent or a chemical heat storage material that is a substance that causes a reversible thermochemical reaction with the reaction medium may be employed, or a latent heat storage material that is a substance that generates heat or absorbs heat by phase change. May be adopted.

  Specific examples of the adsorbent include zeolite, silica gel, and activated carbon. In this case, examples of the reaction medium include water and ethanol.

Specific examples of the chemical heat storage material include inorganic metal salts. In this case, examples of the reaction medium include water and ammonia. More specifically, for example, calcium oxide (CaO), magnesium oxide (MgO), calcium chloride (CaCl ₂ ) may be used as the inorganic metal salt, and water (water vapor) may be used as the reaction medium. Further, for example, calcium chloride or strontium chloride (SrCl ₂ ) may be used as the inorganic metal salt, and ammonia may be used as the reaction medium.

Specific examples of the latent heat storage material include inorganic metal salts such as aluminum chloride (AlCl ₃ ), lithium nitrate (LiNO ₃ ), and sodium nitrate (NaNO ₃ ), sugars such as erythritol and threitol, barium hydroxide octahydrate ( Examples thereof include hydrates of inorganic metal salts such as Ba (OH) ₂ .8H ₂ O).

  Here, when an adsorbent or a chemical heat storage material is used as the heat storage material 1, the heat storage unit 2 is configured so that a reaction medium in a fluid state can flow in and out. Specifically, the heat storage unit 2 includes a supply passage (not shown) for supplying a reaction medium to the heat storage material 1 filled in the heat storage unit 2 in the heat release mode, and a discharge for discharging the reaction medium in the heat storage mode. A passage (not shown) is connected.

  On the other hand, by using a latent heat storage material as the heat storage material 1, it is not necessary to flow in and out of the reaction medium at the time of heat storage and heat dissipation, and therefore it is not necessary to provide the above-described supply passage and discharge passage. Therefore, the heat storage device can be simplified.

  As described above, in the present embodiment, in the heat storage unit 2, the heat storage temperature of the first part where the exhaust temperature is high in the heat storage mode is higher than the heat storage temperature of the second part where the fluid temperature is low in the heat storage mode. As described above, a plurality of types of heat storage materials 1 are provided. According to this, since heat can be stored in the heat storage material 1 having a heat storage temperature corresponding to the temperature of the exhaust gas, which is a heat source, heat can be stored in the heat storage material 1 in a state of high exergy. Therefore, it is possible to suppress a decrease in the quality of heat energy during heat storage.

  Then, by storing heat in the heat storage material 1 in a state of high exergy, in the heat dissipation mode, the temperature difference between the heat storage material 1 and the exhaust to be heated increases, and the heat dissipation output can be increased.

  Here, the relationship between the heat storage temperature and heat storage density of various heat storage materials is shown in FIG. In FIG. 4, the black circle plot indicates the latent heat storage material, and the other plots indicate the chemical heat storage material. As shown in FIG. 4, the heat storage material has a higher heat storage density as the heat storage temperature is higher.

  In the conventional heat storage device, since the heat storage temperature is set according to the part where the exhaust gas temperature becomes the lowest in the heat storage unit, it is necessary to use a heat storage material having a low heat storage density, and the size of the heat storage device is increased. There was a problem.

On the other hand, in the present embodiment, as described above, the heat storage material 1 having a high heat storage temperature is disposed in a portion where the temperature of the exhaust gas, which is a heat source, is high, so that the heat storage density can be increased. As a result, the heat storage device can be downsized.
In addition, by using a chemical heat storage material as the heat storage material 1, as shown in FIG. 4, a heat storage density can be made larger than a latent heat storage material. For this reason, it is possible to further reduce the size of the heat storage device.

  Here, the heat storage temperature of the heat storage material 1 with respect to the position in the exhaust flow direction in the heat storage unit 2, the exhaust temperature in the heat dissipation mode in the heat storage device according to the present embodiment, and the heat dissipation mode in the heat storage device according to the comparative example described later. The relationship of the exhaust temperature is shown in FIG. In FIG. 5, the solid line indicates the heat storage temperature of the heat storage material 1, the broken line indicates the exhaust temperature during the heat dissipation mode in the heat storage device according to the present embodiment, and the alternate long and short dash line indicates the heat dissipation mode in the heat storage device according to the comparative example. The exhaust temperature is shown.

  In the heat storage device according to the comparative example, the flow direction of the exhaust gas in the heat dissipation mode is reversed with respect to the heat storage device according to the present embodiment. That is, the heat storage device according to the comparative example is configured such that exhaust flows from the outlet portion 22 side toward the inlet portion 21 side in the heat dissipation mode. Therefore, the heat storage device according to the comparative example is configured such that the exhaust gas flows from a portion where the exergy of the heat storage material 1 is low to a high portion in the heat dissipation mode. For this reason, in the heat storage device according to the comparative example, the temperature difference between the heat storage material 1 and the exhaust gas is reduced in the heat dissipation mode, as indicated by the one-dot chain line in FIG.

  On the other hand, in this embodiment, it is comprised so that exhaust_gas | exhaustion may flow toward the low site | part from the site | part with high exergy of the thermal storage material 1 at the time of heat dissipation mode. For this reason, as shown by the broken line in FIG. 5, the temperature difference between the heat storage material 1 and the exhaust gas can be maximized in the heat dissipation mode. As a result, the heat output in the heat dissipation mode can be increased.

  Moreover, in this embodiment, the heat storage part 2 is comprised so that the heat transfer area with exhaust_gas | exhaustion may become large, so that the site | part where the exergy of the heat storage material 1 is low at the time of heat dissipation mode. According to this, the heat transfer area of the site | part with which temperature difference with exhaust_gas | exhaustion becomes small at the time of thermal radiation mode can be enlarged, and the heat stored in the heat storage material 1 arrange | positioned at the said site | part can be taken out effectively.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. The second embodiment is different from the first embodiment in that an adhesive 7 is used as a fixing means.

  As shown in FIG. 7, in the present embodiment, the plural types of heat storage materials 1 are bonded to the outer surface of the exhaust pipe 20 by the adhesive 7. That is, each of the plural types of heat storage materials 1 is fixed to a predetermined reference position by the adhesive 7. Therefore, the adhesive 7 of the present embodiment corresponds to the fixing means of the present invention. Examples of the adhesive 7 include an epoxy resin type, an acrylic resin type, and a vinyl acetate type. According to this embodiment, the same effect as the first embodiment can be obtained.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and can be variously modified as follows without departing from the spirit of the present invention. Further, the means disclosed in each of the above embodiments may be appropriately combined within a practicable range.

  (1) In embodiment mentioned above, about the example which has arrange | positioned the thermal storage material 1 in the thermal storage part 2 so that the thermal storage temperature of the thermal storage material 1 may become low step by step as the exhaust gas temperature becomes low at the time of thermal storage mode. Although demonstrated, arrangement | positioning of the thermal storage material 1 is not limited to this. For example, in the heat storage unit 2, as the exhaust gas temperature decreases in the heat storage mode, the heat storage temperature of the heat storage material 1 continuously decreases (more specifically, linearly or quadratic), The heat storage material 1 may be disposed.

  (2) In the above-described embodiment, the example in which the exhaust gas of the internal combustion engine is employed as the fluid that exchanges heat with the heat storage material 1 is described. However, the present invention is not limited to this example. Good.

  (3) In embodiment mentioned above, while using the thermal storage material 1 which stores warm heat, the thermal storage mode which gives the thermal energy stored in the thermal storage material 1 to exhaust_gas | exhaustion (heating object), and the thermal energy which exhaust_gas | exhaustion (heat source) has to thermal storage material. Although the example which comprised the heat storage mode which stores heat so that switching was possible was demonstrated, it is not limited to this. For example, while using the heat storage material 1 that stores cold energy, switching between a cooling mode in which the cold energy stored in the heat storage material 1 is given to the fluid to be cooled and a cold storage mode in which cold heat of the fluid that is the cold heat source is stored in the heat storage material is switched. You may comprise.

  (4) In 1st Embodiment mentioned above, although the example using the metal or resin plate-shaped member was demonstrated as the partition member 6, the material of the partition member 6 is not limited to this. For example, the partition member 6 may be a non-woven fabric configured so that the heat storage material 1 does not pass through.

1 heat storage material 2 heat storage section 10 heat storage

Claims (7)

A heat accumulator (10) having a heat accumulator (2) for accommodating a heat accumulator (1) for storing warm heat;
While being configured to exchange heat between the fluid flowing outside the heat storage section (2) and the heat storage material (1),
And radiating modes providing a heat stored in the heat storage material (1) to the fluid, and a heat storage mode in which heat storage the heat possessed by the fluid to the heat storage material (1) a switchable-configured heat storage device ,
Of the heat storage unit (2), a portion where the temperature of the fluid becomes a first reference temperature determined in the heat storage mode is defined as a first portion (21), and the temperature of the fluid in the heat storage mode is the first temperature. When the part that becomes the second reference temperature lower than the one reference temperature is the second part (22),
The heat storage section (2) includes a plurality of types of the heat storage materials (1) such that the heat storage temperature of the first part (21) is higher than the heat storage temperature of the second part (22) in the heat storage mode. Is provided ,
The said heat storage part (2) is comprised so that the heat transfer area with the said fluid may become large, so that the part where the exergy of the said heat storage material (1) is low at the time of the said heat radiation mode is comprised .   The said 1st site | part (21) is provided in the upstream of the flow direction of the said fluid in the said thermal storage mode with respect to the said 2nd site | part (22), The thermal storage apparatus of Claim 1 characterized by the above-mentioned. .   The heat storage section (2) is provided with the plurality of types of heat storage materials (1) so that the heat storage temperature decreases as the temperature of the fluid decreases in the heat storage mode. The heat storage device according to 1 or 2.   The said thermal storage (10) is comprised so that the said fluid may flow toward the low site | part from the site | part with a high exergy of the said thermal storage material (1) at the time of the said thermal radiation mode. The heat storage apparatus as described in any one.   The said heat storage part (2) has a fixing means (6, 7) which fixes each of the said multiple types of heat storage material (1) to the predetermined reference | standard position, The Claim 1 thru | or 4 characterized by the above-mentioned. The thermal storage apparatus as described in any one of these. The heat storage section (2) is configured such that a reaction medium in a fluid state can flow in and out,
The heat storage device according to any one of claims 1 to 5 , wherein the heat storage material (1) is a substance that causes a reversible thermochemical reaction with the reaction medium. The heat storage device according to any one of claims 1 to 5 , wherein the heat storage material (1) is a substance that generates heat or absorbs heat by phase change.

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