Stacked heat exchanger and heat exchange unit

Abstract

To exchange heat between a heating-objective fluid and a heating medium with an intermediate medium interposed therebetween, in a lamination-type heat exchanger.SOLUTION: A lamination-type heat exchanger 12 comprises: a low-temperature layer 37 in which a low-temperature flow passage 37a into which a heating-objective fluid is introduced is formed; a first high-temperature layer 38 which is laminated while adjoining the low-temperature layer 37, and has a first high-temperature flow passage 38a into which an intermediate medium is introduced; and a second high-temperature layer 39 which is laminated while adjoining the first high-temperature layer 38, and has a second high-temperature flow passage 39a into which a heating medium is introduced. The intermediate medium is composed of an alcohol having a solidification point whose temperature is -80°C or lower at which a liquid state can be maintained even if heat is exchanged between the heating-objective fluid and the heating medium in the first high-temperature flow passage 38a, or an alcohol aqueous solution.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a stacked heat exchanger and a heat exchange unit. [Background technology]

[0002] Conventionally, vaporizers that vaporize low-temperature fluids to be heated, such as liquefied natural gas, have been known. One such vaporizer, as disclosed in Patent Document 1 below, is an intermediate-medium-type vaporizer that vaporizes the fluid to be heated by performing heat exchange between a heat source medium and the fluid to be heated via an intermediate medium. In the vaporizer disclosed in Patent Document 1, an intermediate medium made of propane is housed in a casing. At the lower part of the casing, the liquid intermediate medium vaporizes upon receiving heat from a heat source medium, such as hot water. The vaporized intermediate medium then vaporizes and condenses the fluid to be heated at the upper part of the casing. In this manner, the intermediate medium repeatedly vaporizes and condenses within the casing. Intermediate-medium-type vaporizers utilize the latent heat of the intermediate medium for heat exchange, resulting in high heat exchange efficiency. Therefore, they can vaporize large volumes of the fluid to be heated. Furthermore, the use of an intermediate medium also prevents the heat source medium, such as hot water, from freezing. Furthermore, the evaporation device disclosed in Patent Document 1 is provided with a circulation flow path for utilizing the cold energy of the low-temperature liquid intermediate medium outside the casing, so that the cold energy of the fluid to be heated imparted to the intermediate medium can also be utilized outside the casing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-10683 Summary of the Invention [Problem to be solved by the invention]

[0004] The intermediate medium-type vaporizer disclosed in Patent Document 1 is capable of vaporizing a large amount of a fluid to be heated while suppressing freezing of the heat source medium. However, because the intermediate medium must be repeatedly vaporized and condensed, a section for condensing the gaseous intermediate medium into a liquid intermediate medium and a section for vaporizing the liquid intermediate medium into a gaseous intermediate medium are required. Therefore, the technology of suppressing freezing of a heat source medium by performing heat exchange between the heat source medium and the fluid to be heated through an intermediate medium cannot be directly applied to a stacked heat exchanger having a low-temperature layer and a high-temperature layer.

[0005] Therefore, the present invention was made in consideration of the above-mentioned conventional technology, and its purpose is to enable heat exchange between the fluid to be heated and the heating medium in a stacked heat exchanger by interposing an intermediate medium therebetween. [Means for solving the problem]

[0006] To achieve the above object, the present invention provides a laminated heat exchanger comprising: a low-temperature layer having a low-temperature flow path through which a fluid to be heated is introduced; a first high-temperature layer stacked adjacent to the low-temperature layer and having a first high-temperature flow path through which an intermediate medium is introduced; and a second high-temperature layer stacked adjacent to the first high-temperature layer and having a second high-temperature flow path through which a heating medium is introduced. The intermediate medium is an alcohol or alcohol-water solution having a freezing point of −80°C or lower that remains in a liquid state even when heat exchange occurs between the fluid to be heated and the heating medium in the first high-temperature flow path.

[0007] The stacked heat exchanger of the present invention employs an intermediate medium, such as an alcohol or alcohol-based aqueous solution, with a freezing point of −80°C or lower, which maintains a liquid state during heat exchange with the fluid to be heated and the heating medium. This eliminates the need for a separate component for condensing the gaseous intermediate medium into a liquid or for vaporizing the liquid intermediate medium into a gaseous intermediate medium. Furthermore, since the first high-temperature layer through which the intermediate medium flows is located between the low-temperature layer and the second high-temperature layer, freezing of the heating medium flowing through the second high-temperature layer can be suppressed during heat exchange between the fluid to be heated and the heating medium. Therefore, the stacked heat exchanger can perform heat exchange between the fluid to be heated and the heating medium through the intermediate medium. Furthermore, unlike conventional intermediate-medium vaporizers, which perform heat exchange while evaporating and condensing the intermediate medium, the device design for vaporizing and condensing the intermediate medium is not required. The alcohol or its aqueous solution may be an alcohol or its aqueous solution with a freezing point of −80°C or lower. More preferably, an alcohol or its aqueous solution with a freezing point of −100°C or lower can be used. Intermediates with these freezing points have low viscosity even at low temperatures, so it is expected that pump power will be reduced.

[0008] The heating medium may be an alcohol or alcohol aqueous solution having a freezing point of −80° C. or less that maintains a liquid state even when heat is exchanged with the fluid to be heated and the intermediate medium in the second high-temperature flow path. In this embodiment, the heating medium maintains a liquid state in the second high-temperature flow path, thereby preventing the heating medium from freezing.

[0009] The intermediate medium and the heating medium may be the same type of fluid. In this case, the stacked heat exchanger may have a turn-back header that connects the first high-temperature flow path and the second high-temperature flow path to each other.

[0010] In this embodiment, since the heating medium and the intermediate medium are composed of the same fluid, there is no need to separately provide equipment for the heating medium (e.g., equipment for circulating the heating medium, equipment for supplying the heating medium, etc.) and equipment for the intermediate medium (e.g., equipment for circulating the intermediate medium, equipment for supplying the intermediate medium, etc.), and these can be shared. Furthermore, since there is no need to supply fluid to the first high-temperature flow path and the second high-temperature flow path from separate supply sources, the overall amount of fluid supplied as the heating medium and the intermediate medium can be reduced.

[0011] The heat exchange unit according to the present invention includes the stacked heat exchanger, an intermediate medium flow path through which the intermediate medium flowing out of the stacked heat exchanger flows, and a heat exchanger that recovers the cold of the intermediate medium directly or indirectly from the intermediate medium flowing through the intermediate medium flow path. In this aspect, the cold of the intermediate medium cooled by the fluid to be heated can be recovered in the heat exchanger.

[0012] The heat exchange unit according to the present invention includes the stacked heat exchanger, a fluid flow path through which the fluids functioning as the intermediate medium and the heating medium flow out of the stacked heat exchanger, and a heat exchanger that recovers cold energy from the fluids flowing through the fluid flow path directly or indirectly. In this aspect, the cold energy of the fluid functioning as the intermediate medium cooled by the fluid to be heated can be recovered in the heat exchanger.

[0013] The heat exchange unit according to the present invention includes the stacked heat exchanger, a heating medium flow path through which the heating medium flowing out of the stacked heat exchanger flows, an intermediate medium flow path through which the intermediate medium flowing out of the stacked heat exchanger flows, and a heat exchanger for heating the heating medium flowing through the heating medium flow path and the intermediate medium flowing through the heating medium flow path. flow path and a heating heat exchanger for exchanging heat with the intermediate medium flowing through the heating heat exchanger, and the intermediate medium heated by the heating medium in the heating heat exchanger is introduced into the stacked heat exchanger.

[0014] In this embodiment, the intermediate medium is heated by the heating medium in the heating heat exchanger, and the heated intermediate medium is introduced into the stacked heat exchanger. Therefore, the temperature of the intermediate medium in the stacked heat exchanger is increased, further reducing the risk of the heating medium freezing in the stacked heat exchanger. [Effects of the Invention]

[0015] As described above, according to the present invention, in a stacked heat exchanger, heat can be exchanged between a fluid to be heated and a heating medium via an intermediate medium. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 2 is a schematic view of a heat exchange unit according to the first embodiment. [Figure 2] FIG. 3 is a schematic diagram of a stacked heat exchanger provided in the heat exchange unit. [Figure 3] 3A and 3B are diagrams illustrating the configuration of a stack in the stacked heat exchanger. [Figure 4] FIG. 4 is a schematic view of a heat exchange unit according to a modified example of the first embodiment. [Figure 5] FIG. 4 is a schematic view of a heat exchange unit according to a modified example of the first embodiment. [Figure 6] FIG. 10 is a schematic view of a heat exchange unit according to a second embodiment. [Figure 7] FIG. 10 is a diagram for explaining the configuration of a laminate in a laminate-type heat exchanger according to a second embodiment. [Figure 8] FIG. 10 is a schematic view of a heat exchange unit according to a modified example of the second embodiment. [Figure 9] FIG. 10 is a schematic view of a heat exchange unit according to a modified example of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0018] (First embodiment) 1, a heat exchange unit 10 according to the first embodiment includes a stacked heat exchanger 12, a fluid-to-be-heated flow path 14 connected to the stacked heat exchanger 12 and through which a fluid to be heated flows, a heating medium flow path 16 connected to the stacked heat exchanger 12 and through which a heating medium flows, and an intermediate medium flow path 18 connected to the stacked heat exchanger 12 and through which an intermediate medium flows. As will be described later, the stacked heat exchanger 12 is configured to exchange heat between the heating medium and the fluid to be heated via the intermediate medium.

[0019] The fluid flow path 14 to be heated includes an inflow flow path 14a through which the fluid to be heated flows into the stacked heat exchanger 12, and an outflow flow path 14b through which the fluid to be heated flows out of the stacked heat exchanger 12 after heat exchange.

[0020] The heating medium flow path 16 includes an inflow flow path 16a through which the heating medium flows into the stacked heat exchanger 12, and an outflow flow path 16b through which the heating medium after heat exchange flows out of the stacked heat exchanger 12. A pump 20 for circulating the heating medium is disposed in the heating medium flow path 16. Note that, when the heating medium flow path 16 forms a closed loop as described below, the pump 20 may be provided in at least one of the inflow flow path 16a and the outflow flow path 16b.

[0021] The inlet flow path 16a and outlet flow path 16b of the heating medium flow path 16 may be connected to a heating medium storage section (heating medium storage section 22) so that the heating medium flow path 16 forms a closed loop that circulates the heating medium between the heating medium storage section 22 and the stacked heat exchanger 12. However, the heating medium flow path 16 does not have to form a closed loop. In other words, the inlet flow path 16a and the outlet flow path 16b do not have to be connected to each other.

[0022] The intermediate medium flow path 18 includes an inflow flow path 18a through which the intermediate medium flows into the stacked heat exchanger 12, and an outflow flow path 18b through which the intermediate medium flows out of the stacked heat exchanger 12 after heat exchange.

[0023] The inlet flow path 18a and the outlet flow path 18b of the intermediate medium flow path 18 may be connected to an intermediate medium storage section (intermediate medium storage section 26), so that the intermediate medium flow path 18 forms a closed loop for circulating the intermediate medium between the intermediate medium storage section 26 and the stacked heat exchanger 12. A pump 24 for circulating the intermediate medium is disposed in the intermediate medium flow path 18. Note that, since the intermediate medium flow path 18 is a closed loop, it is sufficient that the pump 24 is disposed in at least one of the inlet flow path 18a and the outlet flow path 18b. However, the intermediate medium flow path 18 may not form a closed loop, and the inlet flow path 18a and the outlet flow path 18b may not communicate with each other.

[0024] Examples of fluids to be heated include cryogenic liquefied gases such as liquefied natural gas (LNG), liquefied nitrogen (LN2), liquid ammonia, and liquid hydrogen (LH2), as well as low-temperature gases such as methane gas, ethane gas, and propane gas. Examples of heating media include water vapor and hot water. Examples of intermediate media include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, and butanol, or aqueous solutions thereof. As the alcohol or aqueous solution thereof, an alcohol or aqueous solution thereof having a freezing point of -80°C or lower is used. However, an alcohol or aqueous solution thereof having a freezing point of -100°C or lower can also be used. These alcohols have lower viscosity than glycol, so pressure loss (reduced pump power) can be reduced compared to using glycol.

[0025] The heat exchange unit 10 is provided with a heat exchanger 30 that recovers the cold energy of the intermediate medium. The heat exchanger 30 is connected to a recovery path 32, both ends of which are connected to the intermediate medium storage section 26. A pump 34 is provided in the recovery path 32. When the pump 34 is operated, the intermediate medium stored in the intermediate medium storage section 26 flows through the recovery path 32 and exchanges heat with another fluid in the heat exchanger 30. This causes the other medium to be cooled by the cold energy of the intermediate medium. In other words, the heat exchanger 30 indirectly recovers the cold energy of the intermediate medium from the intermediate medium flowing through the intermediate medium flow path 18. The intermediate medium that has passed through the heat exchanger 30 is returned to the intermediate medium storage section 26. The other medium may be, for example, air for cooling a room.

[0026] The stacking-type heat exchanger 12 is configured as a so-called microchannel heat exchanger. That is, as shown in Figures 2 and 3, the stacking-type heat exchanger 12 includes a stack 36 including a low-temperature layer 37, a first high-temperature layer 38, and a second high-temperature layer 39, and headers 41 to 46 fixed to the stack 36. The low-temperature layer 37 is formed with a plurality of low-temperature flow paths 37a through which the fluid to be heated is introduced. The first high-temperature layer 38 is formed with a plurality of first high-temperature flow paths 38a through which an intermediate medium is introduced. The second high-temperature layer 39 is formed with a plurality of second high-temperature flow paths 39a through which a heating medium is introduced.

[0027] The headers 41-46 include a low-temperature supply header 41 that distributes the medium to be heated to the multiple low-temperature flow paths 37a, a first supply header 42 that distributes the intermediate medium to the multiple first high-temperature flow paths 38a, a second supply header 43 that distributes the heating medium to the multiple second high-temperature flow paths 39a, a low-temperature collection header 44 that merges the medium to be heated that has flowed through the multiple low-temperature flow paths 37a, a first collection header 45 that merges the intermediate medium that has flowed through the multiple first high-temperature flow paths 38a, and a second collection header 46 that merges the heating medium that has flowed through the multiple second high-temperature flow paths 39a. The low-temperature supply header 41 is connected to the inflow flow path 14a of the fluid to be heated flow path 14, and the low-temperature collection header 44 is connected to the outflow flow path 14b of the fluid to be heated flow path 14. The first supply header 42 is connected to the inflow flow path 18a of the intermediate medium flow path 18, and the first collection header 45 is connected to the outflow flow path 18b of the intermediate medium flow path 18. The second supply header 43 is connected to the inlet flow path 16 a of the heating medium flow path 16 , and the second collection header 46 is connected to the outlet flow path 16 b of the heating medium flow path 16 .

[0028] 3, in the laminate 36, a first high temperature layer 38 is adjacent to a low temperature layer 37, a second high temperature layer 39 is adjacent to the first high temperature layer 38, another first high temperature layer 38 is adjacent to the second high temperature layer 39, another first high temperature layer 38 is adjacent to another low temperature layer 37, and yet another first high temperature layer 38 is adjacent to this other first high temperature layer 38. In other words, the low temperature layer 37, the first high temperature layer 38, and the second high temperature layer 39 are laminated such that the first high temperature layer 38 is sandwiched between the low temperature layer 37 and the second high temperature layer 39.

[0029] The low temperature layer 37 is a flat region and is formed with a plurality of aligned low temperature flow paths 37a. The first high temperature layer 38 is also a flat region and is formed with a plurality of aligned first high temperature flow paths 38a. The second high temperature layer 39 is also a flat region and is formed with a plurality of aligned second high temperature flow paths 39a.

[0030] In the stacked heat exchanger 12, the fluid to be heated flows into each low-temperature flow path 37a through the low-temperature supply header 41, the intermediate medium flows into each first high-temperature flow path 38a through the first supply header 42, and the heating medium flows into each second high-temperature flow path 39a through the second supply header 43. In the stacked body 36, the liquid fluid to be heated flowing through the low-temperature flow path 37a is heated by the heat of the heating medium flowing through the second high-temperature flow path 39a. If the fluid to be heated were liquid, it would evaporate. However, because heat exchange between the heating medium and the fluid to be heated occurs via the intermediate medium, the heating medium is prevented from freezing. The intermediate medium is cooled by the fluid to be heated but does not condense, and is heated by the heating medium but does not evaporate. Therefore, the intermediate medium remains liquid as it flows through the first high-temperature flow path 38a.

[0031] The fluids to be heated that have flowed through each low-temperature flow path 37a join together through a low-temperature collecting header 44 and are discharged into the outlet flow path 14b of the fluid to be heated flow path 14. The intermediate medium that has flowed through each first high-temperature flow path 38a joins together through a first collecting header 45 and is discharged into the outlet flow path 18b of the intermediate medium flow path 18. The heating medium that has flowed through each second high-temperature flow path 39a joins together through a second collecting header 46 and is discharged into the outlet flow path 16b of the heating medium flow path 16.

[0032] It is also possible to measure the temperature of the heating medium stored in the heating medium reservoir 22, the temperature of the heating medium flowing through the outlet flow path 16b of the heating medium flow path 16, and the flow rate of the heating medium in the heating medium flow path 16. In this case, when the temperature of the heating medium drops, i.e., when the risk of freezing increases, additional control may be added, such as heating the heating medium or increasing the flow rate of the heating medium. In this case, the risk of the heating medium freezing can be further reduced.

[0033] It is also possible to measure the temperature of the intermediate medium stored in the intermediate medium storage section 26, the temperature of the intermediate medium flowing through the outlet flow path 18b in the intermediate medium flow path 18, and the flow rate of the intermediate medium in the intermediate medium flow path 18. In this case, when the temperature of the intermediate medium drops, that is, when the risk of freezing increases, additional control may be added, such as heating the intermediate medium (for example, by exchanging heat with another medium in the heat exchanger 30) or increasing the flow rate of the intermediate medium.

[0034] As described above, the stacked heat exchanger 12 of this embodiment employs an intermediate medium, such as alcohol or an alcohol-water solution, having a freezing point of −80°C or below, which maintains a liquid state during heat exchange with the fluid to be heated and the heating medium. Therefore, neither a section for condensing the gaseous intermediate medium into a liquid intermediate medium nor a section for vaporizing the liquid intermediate medium into a gaseous intermediate medium is required. Furthermore, because the first high-temperature layer 38 through which the intermediate medium flows is located between the low-temperature layer 37 and the second high-temperature layer 39, freezing of the heating medium flowing through the second high-temperature layer 39 can be suppressed during heat exchange between the fluid to be heated and the heating medium. Therefore, the stacked heat exchanger 12 can perform heat exchange between the fluid to be heated and the heating medium through the intermediate medium. Furthermore, unlike conventional intermediate-medium vaporizers, which perform heat exchange while evaporating and condensing the intermediate medium, a device design for vaporizing and condensing the intermediate medium is not required.

[0035] 1, the intermediate medium storage unit 26 that stores the intermediate medium may be configured as a single tank, but is not limited to this. For example, the intermediate medium storage unit 26 may be divided into a first tank provided in the inlet flow path 18a of the intermediate medium flow path 18 and a second tank provided in the outlet flow path 18b of the intermediate medium flow path 18. In this case, the upstream end of the recovery path 32 is connected to the first tank, and the downstream end of the recovery path 32 is connected to the second tank. In other words, the first tank stores the low-temperature intermediate medium that has flowed out of the stacked heat exchanger 12 and is not yet heat exchanged with another medium in the heat exchanger 30, and the second tank stores the intermediate medium that has been heat exchanged with another medium in the heat exchanger 30.

[0036] Dividing the intermediate medium storage unit 26 into a first tank and a second tank increases operational flexibility. This is therefore suitable for applications where the supply and demand of cold energy fluctuates greatly and the system is frequently started and stopped. Note that the capacities of the first tank and the second tank do not necessarily have to be the same.

[0037] 1, the heat exchanger 30 is connected to the recovery path 32, but the configuration is not limited to this. For example, as shown in FIG. 4, the heat exchanger 30 may be connected to the outlet path 18b of the intermediate medium path 18. In this case, the heat exchanger 30 directly recovers the cold of the intermediate medium from the intermediate medium flowing through the intermediate medium path 18.

[0038] In this case, the cold can be recovered from the intermediate medium that has received the cold in the stacked heat exchanger 12 before it returns to the intermediate medium storage section 26. Therefore, the cold can be recovered in the intermediate medium storage section 26 before the temperature rises due to mixing with the intermediate medium after heat exchange in the heat exchanger 30, so that cold at a lower temperature can be recovered.

[0039] The heat exchange unit 10 in FIG. 1 is provided with a heat exchanger 30 for recovering cold from the intermediate medium. However, if there is no demand for cold, this heat exchanger 30 can be omitted. Alternatively, as shown in FIG. 5, a heating heat exchanger 50 for heating the intermediate medium can be provided. The heating heat exchanger 50 is connected to the outlet flow path 18b of the intermediate medium flow path 18 and the outlet flow path 16b of the heating medium flow path 16. The heating heat exchanger 50 heats the intermediate medium with the heating medium. This increases the temperature of the intermediate medium stored in the intermediate medium storage section 26 and the intermediate medium introduced into the stacked heat exchanger 12. In other words, in the heating heat exchanger 50, heat exchange occurs between the heating medium and the intermediate medium in the absence of a fluid to be heated. This occurs in a high-temperature range and does not involve a phase change. This effectively increases the temperature of the intermediate medium. Therefore, the temperature of the intermediate medium in the stacked heat exchanger 12 also increases, further reducing the risk of freezing of the heating medium in the stacked heat exchanger 12. The heating heat exchanger 50 may be formed integrally with the stacked heat exchanger 12.

[0040] (Second embodiment) 6 shows the second embodiment. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0041] 6, in the heat exchange unit 10 of the second embodiment, the heating medium flow path 16 is omitted, and the stacked heat exchanger 12 is connected to the heating target fluid flow path 14 and the intermediate medium flow path 18. On the other hand, the stack 36 of the stacked heat exchanger 12 has a low temperature layer 37, a first high temperature layer 38, and a second high temperature layer 39, similar to the first embodiment.

[0042] The fluid to be heated flows into the plurality of low-temperature flow paths 37a of the low-temperature layer 37 from the inlet flow paths 14a of the fluid flow path 14 to be heated. The fluid to be heated that has flowed through the plurality of low-temperature flow paths 37a flows out to the outlet flow paths 14b of the fluid flow path 14 to be heated.

[0043] The intermediate medium flows into the second high-temperature flow passages 39a of the second high-temperature layer 39 from the inlet flow passages 18a of the intermediate medium flow passage 18. As shown in FIG. 7, the intermediate medium that has flowed through the second high-temperature flow passages 39a flows into the first high-temperature layer 38's first high-temperature flow passages 38a via a return header 52. The return header 52 is a header that connects the second high-temperature flow passages 39a and the first high-temperature flow passages 38a to each other. The intermediate medium that has flowed through the first high-temperature flow passages 38a flows out into the outlet flow passages 18b of the intermediate medium flow passage 18. In other words, the outlet flow passages 18b of the intermediate medium flow passage 18 function as a fluid flow passage that discharges the fluid that functions as the intermediate medium and heating medium from the stacked heat exchanger 12. Therefore, in the stacked heat exchanger 12 of the second embodiment, the intermediate medium flowing through the second high-temperature flow passage 39a serves as a heating medium. In this embodiment, the temperature of the fluid flowing through the second high temperature layer 39 is lower than in the first embodiment, but freezing in the second high temperature flow path 39a can be suppressed.

[0044] In the stack 36 (stack-type heat exchanger 12) shown in FIG. 7, the intermediate medium is introduced from multiple second high-temperature flow paths 39a included in one second high-temperature layer 39 to multiple first high-temperature flow paths 38a included in two adjacent first high-temperature layers 38 on both sides of the second high-temperature layer 39. In this case, if the cross-sectional area of ​​each second high-temperature flow path 39a is the same as the cross-sectional area of ​​each first high-temperature flow path 38a, the flow velocity of the intermediate medium in the second high-temperature flow path 39a is twice that of the first high-temperature flow path 38a. Therefore, while the increased flow velocity increases the heat transfer coefficient, reducing the risk of freezing, it also increases pressure loss. In this case, if there is a limit to the pressure loss, measures can be taken, such as increasing the number of second high-temperature flow paths 39a or increasing the cross-sectional area of ​​the second high-temperature flow path 39a. Note that it is preferable to prevent a decrease in the flow velocity of the intermediate medium in the first high-temperature flow path 38a to avoid the risk of freezing of the intermediate medium in the first high-temperature flow path 38a.

[0045] 7, the intermediate medium flowing in from the inlet flow passage 18a of the intermediate medium flow passage 18 flows into the plurality of second high-temperature flow passages 39a and then passes through the return header 52, but the configuration is not limited to this. That is, a connection structure may be used in which the intermediate medium flowing in from the inlet flow passage 18a of the intermediate medium flow passage 18 flows into the plurality of first high-temperature flow passages 38a, and the intermediate medium flowing through the first high-temperature flow passages 38a flows into the plurality of second high-temperature flow passages 39a through the return header 52. In this case as well, the outlet flow passage 18b of the intermediate medium flow passage 18 functions as a fluid flow passage that allows the fluid that functions as the intermediate medium and heating medium to flow out of the stacked heat exchanger 12.

[0046] Returning to Figure 6, as shown in the figure, a heat exchanger 30 is provided in the outlet flow path 18b of the intermediate medium flow path 18 to exchange heat between the intermediate medium and another medium and recover the cold energy of the intermediate medium. In other words, the heat exchanger 30 recovers the cold energy of the intermediate medium directly from the intermediate medium flowing through the intermediate medium flow path 18.

[0047] In this embodiment, the temperature of the other medium before heat exchange in the heat exchanger 30, the temperature of the other medium after heat exchange in the heat exchanger 30, and the flow rate of the other medium may be measured, and if the temperature of the other medium drops, i.e., if the risk of freezing increases, control may be added to heat the other medium or increase the flow rate of the other medium, thereby reducing the risk of freezing of the other medium.

[0048] Furthermore, the temperature of the intermediate medium reservoir 26, the temperature of the intermediate medium before heat exchange in the heat exchanger 30, and the flow rate of the intermediate medium may be measured, and if the temperature of the intermediate medium drops, i.e., if the risk of freezing increases, the intermediate medium may be heated (in this case, heat exchanged with a medium for recovering cold energy) or the flow rate of the intermediate medium may be increased. This can reduce the risk of the intermediate medium freezing.

[0049] In the second embodiment, the intermediate medium is introduced into the stacked heat exchanger 12, while the heating medium is not introduced into the stacked heat exchanger 12. For this reason, as shown in FIG. 8 , a heater 54 may be provided to heat the intermediate medium that has exchanged heat with the fluid to be heated. For example, the intermediate medium storage section 26 is provided with a recovery path 32 having both ends connected. The heater 54 is provided in this recovery path 32. A heat source medium flow path 56 through which a heat source medium flows is connected to the heater 54, and heat exchange occurs between the intermediate medium and the heat source medium in the heater 54, heating the intermediate medium. In other words, the heater 54 also functions as a heat exchanger 30 that indirectly recovers the cold of the intermediate medium from the intermediate medium flowing through the intermediate medium flow path 18.

[0050] 9, the heater 54 may be provided in the outlet flow path 18b of the intermediate medium flow path 18. The heater 54 also functions as a heat exchanger 30 that directly recovers the cold energy of the intermediate medium flowing through the intermediate medium flow path 18.

[0051] Although a description of other configurations, actions, and effects will be omitted, the description of the first embodiment can be applied to the second embodiment.

[0052] It should be noted that the embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The present invention is not limited to the above-described embodiments, and various modifications and improvements are possible without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0053] 10: Heat exchange unit 12: Stacked heat exchanger 16: Heating medium flow path 18: Intermediate medium flow path 30: Heat exchanger 37: Low temperature layer 37a: Low temperature flow path 38: First high temperature layer 38a: 1st high temperature flow path 39: Second high temperature layer 39a: Second high temperature flow path 50: Heating heat exchanger 52: Folded header

Claims

1. a low-temperature layer having a low-temperature flow path through which a fluid to be heated is introduced; a first high temperature layer laminated adjacent to the low temperature layer and having a first high temperature flow path through which an intermediate medium is introduced; a second high-temperature layer stacked adjacent to the first high-temperature layer and having a second high-temperature flow path through which a heating medium is introduced; The intermediate medium is a stacked heat exchanger made of alcohol or an alcohol aqueous solution having a freezing point of -80 ° C or less that maintains a liquid state even when heat exchange occurs with the fluid to be heated and the heating medium in the first high-temperature flow path.

2. 2. The stacked heat exchanger according to claim 1, wherein the heating medium is an alcohol or an alcohol aqueous solution having a freezing point of −80° C. or less that maintains a liquid state even when heat-exchanging with the fluid to be heated and the intermediate medium in the second high-temperature flow path.

3. the intermediate medium and the heating medium are made of the same type of fluid; 3. The stacked heat exchanger according to claim 2, further comprising a turn-back header that connects the first high temperature flow path and the second high temperature flow path to each other.

4. The stacked heat exchanger according to claim 1 or 2; an intermediate medium flow path through which the intermediate medium flowing out of the stacked heat exchanger flows; a heat exchanger that directly or indirectly recovers cold heat from the intermediate medium flowing through the intermediate medium flow path.

5. The stacked heat exchanger according to claim 2 or 3; a fluid flow path through which the fluids functioning as the intermediate medium and the heating medium flow out of the stacked heat exchanger; a heat exchanger that directly or indirectly recovers cold from the fluid flowing through the fluid flow path.

6. The stacked heat exchanger according to claim 1 or 2; a heating medium flow path through which the heating medium flowing out of the stacked heat exchanger flows; an intermediate medium flow path through which the intermediate medium flowing out of the stacked heat exchanger flows; a heating heat exchanger that exchanges heat between the heating medium flowing through the heating medium flow path and the intermediate medium flowing through the intermediate medium flow path, A heat exchange unit in which an intermediate medium heated by a heating medium in the heating heat exchanger is introduced into the stacked heat exchanger.

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