Heat dissipation devices and server cooling systems

Abstract

In the server cooling system S according to the present embodiment, the heat exhaust device 1 includes an air-cooled heat exchanger 30 having a heat exchange core 30 including a first surface 30A and a second surface 30B, and a plurality of fans 20 that move air as a gas from the first surface 30A to the second surface 30B by rotating an impeller. The heat exchange core 30 has a plurality of tubes 313, 323 that pass a heat medium that is heat exchanged with the air. The tubes 313, 323 each extend in a serpentine manner from the second surface 30B side to the first surface 30A side, and the heat medium flows in each of the tubes 313, 323 from the second surface 30B side to the first surface 30A side.

Description

Technical Field

[0001] Embodiments of the present invention relate to a waste heat recovery device and a server cooling system.

Background Art

[0002] In recent years, the demand for cloud services, generative AI, etc. has been rapidly increasing, and in response, the construction of new data centers has been rapidly expanding.

[0003] Various devices such as servers are installed in a data center. Servers installed in recent data centers are equipped with many arithmetic units such as CPUs and GPUs. And such arithmetic units are performing arithmetic processing with a very large load compared to the past.

[0004] The power consumption of the arithmetic unit increases in proportion to the load of the arithmetic processing of the arithmetic unit. Therefore, the power consumption of devices such as servers in recent data centers has become very large.

[0005] Also, the amount of heat generated and the temperature of the arithmetic unit increase in proportion to the processing load and power consumption of the arithmetic unit. Although the guaranteed operating temperature of the arithmetic unit is generally set relatively high, excessive temperature rise of the arithmetic unit can cause malfunction of the arithmetic unit. Therefore, in a data center, it is necessary to properly cool devices such as servers.

[0006] Cooling of devices such as servers has been carried out conventionally (for example, JP2017-33427A). However, in recent data centers, the amount of heat generated by devices such as servers has become significantly larger than in the past, and it is required to cool the devices with a significantly larger cooling capacity than in the past.

Summary of the Invention

[0007] As described above, in recent years, computing devices such as servers installed in data centers perform computing processes with a much higher load than before. Therefore, the power consumption of devices such as servers has become extremely large. Also, the amount of heat generated by the computing device tends to be significantly larger than before. Therefore, in recent data centers, an increase in power consumption for computing and an increase in power consumption for cooling have become problems.

[0008] As an index for evaluating the efficiency of cooling with respect to power consumption, there is COP (Coefficient Of Performance). COP is determined by cooling capacity / power consumption, and the higher it is, the higher the cooling efficiency. In previous data centers, since the power consumption related to computing and cooling was not excessive, it cannot necessarily be said that cooling facilities were constructed with an emphasis on COP. However, in the cooling of future data centers, it is desired to improve COP as much as possible.

[0009] Also, in the construction of cooling facilities in current or future data centers where a large amount of heat generation is assumed, effective cooling cannot be achieved unless the introduction cost, characteristics inside the data center, etc. are considered more thoroughly than before.

[0010] Specifically, in previous data centers, generally, even a low-output air-cooled waste heat removal device alone was sufficient to cool the equipment. However, such a previous waste heat removal device cannot sufficiently discharge, for example, the amount of heat that can be generated by equipment in current data centers and cannot sufficiently respond to the desired cooling. In such a situation, for example, if a cooling tower is installed in a data center like a semiconductor manufacturing factory, it is considered that the equipment can be cooled efficiently. However, the installation of a cooling tower can be over-spec for the cooling of the data center, so the introduction cost can be a problem. Also, considering the operation of the cooling tower, it cannot necessarily be said that it is efficient from the perspective of power consumption.

[0011] On the one hand, when using an air-cooled exhaust heat device as before, if the blower is driven at a large air volume, a large cooling capacity can be ensured. However, in this case, the COP may increase. Also, dust may be lifted, leading to an undesirable situation for equipment maintenance. Furthermore, noise may also become a problem. Additionally, when the air volume is increased, the pressure loss increases, and the cooling performance may sometimes deteriorate.

[0012] Moreover, the use of a cooling tower or a large-air-volume blower may lead to an increase in the size of the exhaust heat device or the entire equipment including the exhaust heat device. Although a relatively large equipment installation space is generally ensured in a data center, if the occupied space of the cooling equipment such as the exhaust heat device can be suppressed, the number of installed servers etc. can be increased. Therefore, it is naturally desirable to perform efficient cooling while suppressing the occupied space of the cooling equipment.

[0013] As described above, for example, there are various considerations for cooling required in future data centers, and the establishment of an effective cooling method is in the trial-and-error stage.

[0014] In particular, the inventor of the present case infers that server racks with a heat generation amount of about 150 kW per unit will be introduced in large numbers in future data centers. Specifically, for example, if such a server rack can be cooled in a manner suitable for a data center and extremely efficiently, it can greatly contribute to solving the power consumption problem assumed in future data centers.

[0015] The present disclosure was conceived from the above background, and an object thereof is to provide an exhaust heat device and a server cooling system that can preferably achieve efficient cooling while suppressing the introduction cost and the device occupied space.

[0016] Embodiments of the present invention relate to the following aspects.

[0017] <1>An air-cooled heat exchanger having a heat exchange core including a first surface and a second surface opposite to the first surface, A plurality of blowers that cause a gas to flow such that the gas passes from the first surface to the second surface by rotation of the impeller. The heat exchange core has a plurality of tubes through which a heat medium that exchanges heat with the gas flows. Each of the tubes extends while meandering from the second surface side toward the first surface side, and the heat medium flows from the second surface side toward the first surface side in each of the tubes. An exhaust heat device.

[0018] <2>The heat exchanger has an inflow portion that receives the heat medium from the outside and causes it to flow into the tubes. Each of the tubes branches off in parallel from the inflow portion. The exhaust heat device according to <1>.

[0019] <3>The tubes form a meandering shape by alternately and sequentially connecting a straight main flow path element and a U-shaped return flow path element. The plurality of blowers are arranged in a state where the extension line of the rotation axis of the impeller is orthogonal to the second surface. When viewed in the direction from the first surface toward the second surface, the adjacent main flow path elements connected by the return flow path element do not overlap at least partially. The exhaust heat device according to <1> or <2>.

[0020] <4>The heat exchanger has a plurality of plate fins that extend parallel to the direction from the first surface toward the second surface and are arranged in a direction orthogonal to the direction from the first surface toward the second surface. The tubes extend while meandering from the second surface side toward the first surface side while passing through the plurality of plate fins and contact the plate fins. The exhaust heat device according to any one of <1> to <3>.

[0021] <5>The plurality of blowers are arranged in a plurality of rows and a plurality of columns. The exhaust heat device according to claim 1.

[0022] <6>The areas of the first surface and the second surface of the heat exchange core are each 1.5 m 2Above 1.7 m 2 Set it below, The air volume of the gas flowing through the plurality of the blowers is set to be 345 m 3 / min or more and 375 m 3 / min or less, Select the heat medium and set the flow rate of the heat medium so that the value (C·L) obtained by multiplying the specific heat C (kJ / kg·K) of the heat medium at 20°C to 40°C by the flow rate L (L / min) of the heat medium is between 250 and 320, The waste heat removal device according to any one of <1> to <5>, which outputs a cooling capacity of 140 kW or more and 160 kW or less.

[0023] <7> The waste heat removal device according to <6>, wherein the heat medium cooling efficiency (LPM / kW) determined by dividing the flow rate (L / min: LPM) of the heat medium by the cooling capacity is 1.4 or more.

[0024] <8> The waste heat removal device according to <6> or <7>, which has a COP of 15 or more and outputs a cooling capacity of 140 kW or more and 160 kW or less.

[0025] <9> The heat exchanger extends parallel to the direction from the first surface to the second surface and has a plurality of plate fins arranged in a direction orthogonal to the direction from the first surface to the second surface, The tube extends while meandering from the second surface side to the first surface side while passing through the plurality of plate fins and contacts the plate fins, The total of the areas of the heat exchange surfaces of the plurality of plate fins and the area of the heat exchange surface of the tube is 600 m 2 or more. The waste heat removal device according to any one of <1> to <8>.

[0026] <10> The heat exchange core includes a first heat exchange core and a second heat exchange core, and the first heat exchange core and the second heat exchange core are arranged adjacent to each other, The heat exchanger includes, as the inflow portions, an inflow portion connected to the tube of the first heat exchange core and an inflow portion connected to the tube of the second heat exchange core, which are separated from each other. The inflow portion connected to the tube of the first heat exchange core and the inflow portion connected to the tube of the second heat exchange core each extend in a direction in which the first heat exchange core and the second heat exchange core are adjacent to each other. The inflow portion connected to the tube of the first heat exchange core and the inflow portion connected to the tube of the second heat exchange core are displaced in a direction from the first surface toward the second surface, and when viewed in the direction from the first surface toward the second surface, an end portion on the second heat exchange core side of the inflow portion connected to the tube of the first heat exchange core overlaps an end portion on the first heat exchange core side of the inflow portion connected to the tube of the second heat exchange core. The exhaust heat device according to <2>.

[0027] <11> The inlet of the heat medium in the inflow portion connected to the tube of the first heat exchange core and the inlet of the heat medium in the inflow portion connected to the tube of the second heat exchange core open in a direction from the first surface toward the second surface or the opposite direction. The exhaust heat device according to <10>.

[0028] <12> The exhaust heat device includes two of the heat exchangers. The two heat exchangers are arranged so as to form a V shape. A part of the plurality of blowers is arranged so that an extension line of the rotation axis of the impeller intersects the second surface of one of the two heat exchangers and is adjacent to one of the heat exchangers. Another part of the plurality of blowers is arranged so that an extension line of the rotation axis of the impeller intersects the second surface of the other of the two heat exchangers and is adjacent to the other of the heat exchangers. The exhaust heat device according to any one of <1> to <11>.

[0029] <13> The setting of the air volume of the gas flowed by the plurality of the blowers or the setting of the rotation speed of the plurality of the blowers are different according to the distance between each of the blowers and the adjacent heat exchanger, the exhaust heat device according to <12>.

[0030] <14> An exhaust heat device according to any one of <1> to <13> above, and a server rack supplied with the heat medium from the exhaust heat device. The server rack has a cooling flow path for receiving and circulating the heat medium after exchanging heat with the gas, and returns the heat medium flowing out of the cooling flow path to the exhaust heat device, a server cooling system.

[0031] According to an embodiment of the present invention, efficient cooling can be suitably realized while suppressing the introduction cost and the device occupation space.

Brief Description of Drawings

[0032]

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Mode for Carrying Out the Invention

[0033] Hereinafter, an embodiment will be described.

[0034] <Configuration of Server Cooling System> FIG. 1 is a perspective view of a server cooling system S according to an embodiment. The server cooling system S includes a waste heat removal device 1 and a server rack 100.

[0035] The waste heat removal device 1 and the server rack 100 are installed adjacent to each other in the horizontal direction. FIG. 1 shows an example in which the server cooling system S is installed in a data center. However, the location where the server cooling system S is used is not limited to a data center.

[0036] The server rack 100 houses a plurality of servers 102 as electronic devices inside a rack body 101. The rack body 101 has shelf portions arranged in the vertical direction (not shown). In the illustrated example, the servers 102 are installed on each of the plurality of shelf portions in the rack body 101. As a result, the plurality of servers 102 are housed in the rack body 101 so as to overlap in the vertical direction. The server 102 may be configured to include an arithmetic device such as a CPU or GPU, a memory, and the like.

[0037] <Exhaust heat device> The exhaust heat device 1 is a device that extracts heat generated from the server 102 inside the rack body 101, thereby cooling the server 102. The exhaust heat device 1 includes a rectangular parallelepiped housing 10, an air-cooled heat exchanger 30 (see FIGS. 3, 4, etc.), and a blower 20.

[0038] The housing 10 is open on both sides in a direction orthogonal to the horizontal plane in the direction where the exhaust heat device 1 and the server rack 100 are adjacent to each other. The housing 10 houses the heat exchanger 30 inside. And the blower 20 is held by the housing 10 so as to fill the open part on one side of the housing 10.

[0039] The heat exchanger 30 is an air-cooled type that cools the heat medium, which is a liquid flowing inside it, by exchanging heat with air as a gas. The blower 20 causes air to flow so that the air passes through the heat exchanger 30, thereby promoting the heat exchange between the heat medium and the air.

[0040] In the exhaust heat device 1, the heat medium cooled by the heat exchanger 30 is supplied to the server rack 100. At this time, the heat medium extracts heat from the server 102 to cool the server 102. And after the heat medium cools the server 102, it returns to the heat exchanger 30. And the heat medium that has returned to the heat exchanger 30 is cooled again by air and then supplied to the server rack 100 again. Hereinafter, the blower 20 and the heat exchanger 30 constituting the exhaust heat device 1 will be described in detail.

[0041] (Blower) FIG. 2 is a view of the exhaust heat device 1 seen in the direction of arrow II in FIG. 1. FIG. 3 is a cross-sectional view of the exhaust heat device 1 taken along line III-III in FIG. 2.

[0042] As shown in FIG. 2, the exhaust heat device 1 includes a plurality of blowers 20. In the present embodiment, the plurality of blowers 20 are arranged adjacent to the heat exchanger 30 and are arranged in a state of multiple rows and multiple columns. Specifically, the blower 20 is adjacent to the heat exchanger 30 in the horizontal direction. The state where the blower 20 is adjacent to the heat exchanger 30 in the horizontal direction means the positional relationship between the blower 20 and the heat exchanger 30 such that a straight line extending horizontally from any part of the blower 20 passes through any part of the heat exchanger 30.

[0043] In FIG. 3, reference numeral 30C indicates the heat exchange core 30C in the heat exchanger 30 that exchanges heat between the heat medium and air. The heat exchange core 30C includes a first surface 30A and a second surface 30B opposite to the first surface 30A. The plurality of blowers 20 are specifically arranged adjacent to the second surface 30B of the heat exchange core 30C. In particular, it is preferable that the blower 20 is arranged adjacent to the second surface 30B in a state where the extension line of the rotation axis Ax of its impeller 21 described later intersects the second surface 30B, and in the present embodiment, it is arranged in such a manner. The first surface 30A of the heat exchange core 30C faces one side in the direction in which the housing 10 is open, and the second surface 30B of the heat exchange core 30C faces the other side in the direction in which the housing 10 is open.

[0044] The blower 20 has an impeller 21 and a casing 22 that rotatably supports the impeller 21 around the rotation axis Ax. The blower 20 is an axial flow type. The blower 20 causes air to flow so that the air passes from the first surface 30A to the second surface 30B of the heat exchange core 30C by the rotation of the impeller 21. Each of the plurality of blowers 20 is specifically arranged adjacent to the second surface 30B in a state where the extension line of the rotation axis Ax of its impeller 21 intersects, specifically, is orthogonal to the second surface 30B. In the present embodiment, the rotation axis Ax of the impeller 21 of each blower 20 is along the horizontal direction (parallel), but the blower 20 may be arranged such that the rotation axis Ax of the impeller 21 is inclined with respect to the horizontal direction.

[0045] In this embodiment, a plurality of blowers 20 are arranged in a specific state of 8 rows and 4 columns. That is, the heat exchanger 30 includes 32 blowers 20. The number and arrangement mode of the blowers 20 are not limited, and there may be only one blower 20. However, when a plurality of blowers 20 are used, when a part of the blowers 20 is damaged, it is possible to flow air with the remaining blowers 20, so that a decrease in the function of the exhaust heat device 1 can be suppressed. Also, compared with the case of using one large blower, the power of the blower for obtaining a desired cooling capacity can be suppressed.

[0046] Particularly when the blowers 20 are arranged in 4 rows or more and 4 columns or more, by distributing two or more blowers 20 vertically or horizontally with reference to the center of the heat exchange core 30C or the vicinity thereof, a decrease in the function of the exhaust heat device 1 when a part of the blowers 20 is damaged can be effectively suppressed. In this embodiment, 16 blowers 20 are distributed vertically and horizontally with reference to the center of the heat exchange core 30C. When a plurality of blowers 20 are used, each blower 20 may have the same structure and the same size, or the structure and / or size may be different. In this embodiment, each blower 20 has the same structure and the same size, and when basically the same power is applied, it is driven at the same rotation speed and outputs the same air volume. In this embodiment, all of the plurality of blowers 20 are driven to output the same air volume, but the air volume or rotation speed of some of the blowers 20 may be made different from those of the other part. For example, within the housing 10 or the matrix of the blowers 20, the frictional resistance to the air flow can be greater on the outer peripheral side than on the center side. Considering this, the air volume or rotation speed of the blowers 20 located on the outer peripheral side (housing 10 side) among the plurality of blowers 20 may be made larger than that of the blowers 20 located closer to the center side than the blowers on the outer peripheral side.

[0047] In addition, when the blowers 20 are arranged in four or more rows and four or more columns, the amount of air linearly passing from the first surface 30A to the second surface 30B can be increased. In this case, it can be advantageous in terms of suppressing pressure loss and improving heat exchange efficiency. Further, in the present embodiment, the blowers 20 are arranged adjacent to the second surface 30B, but the blowers 20 may be arranged adjacent to the first surface 30A and the gas may be made to flow so as to pass from the first surface 30A to the second surface 30B. However, since the temperature of the gas rises when the gas passes through the blowers 20, from the viewpoint of cooling efficiency, it is preferable that the blowers 20 are arranged on the downstream side of the heat exchange core 30C, that is, adjacent to the second surface 30B.

[0048] (Heat exchanger) The heat exchanger 30 includes a heat exchange core 30C including the above-described first surface 30A and second surface 30B. As shown in FIG. 3, the heat exchange core 30C has a plurality of tubes 313, 323 through which a heat medium flows. The heat exchange core 30C cools the heat medium by heat-exchanging the heat medium flowing through the tubes 313, 323 with the air passing through the heat exchange core 30C. The first surface 30A and the second surface 30B are parallel to each other, but they may not be parallel.

[0049] FIG. 4 is a view of the heat exchanger 30 seen in the direction of arrow IV in FIG. 3. FIG. 5 is a side view of the heat exchanger 30 shown in FIG. 4. As shown in FIGS. 3 to 5, the heat exchange core 30C in the present embodiment includes an upper heat exchange core 310 and a lower heat exchange core 320. The upper heat exchange core 310 is stacked on the lower heat exchange core 320 from above. The upper heat exchange core 310 corresponds to the first heat exchange core, and the lower heat exchange core 320 corresponds to the second heat exchange core and is arranged adjacent to each other.

[0050] The upper heat exchange core 310 includes an upper first surface 310A and an upper second surface 310B opposite to the upper first surface 310A. The lower heat exchange core 320 includes a lower first surface 320A and a lower second surface 320B opposite to the lower first surface 320A. The upper first surface 310A and the lower first surface 320A are arranged vertically to form the first surface 30A of the heat exchange core 30C. The upper second surface 310B and the lower second surface 320B are arranged vertically to form the second surface 30B of the heat exchange core 30C.

[0051] Both the upper heat exchange core 310 and the lower heat exchange core 320 are generally rectangular parallelepiped-shaped when viewed schematically. The upper part and both side parts of the upper heat exchange core 310 are covered and joined by an upper frame 311. The lower part and both side parts of the lower heat exchange core 320 are covered and joined by a lower frame 321. The upper heat exchange core 310 and the lower heat exchange core 320 are integrated by connecting the upper frame 311 and the lower frame 321 vertically to form the heat exchange core 30C.

[0052] The heat exchanger 30 has an inflow part 315, 325 that receives a heat medium from the outside (the server rack 100 side) and allows it to flow into the tubes 313, 323, and an outflow part 316, 326 that receives the heat medium flowing out of the tubes 313, 323 and allows it to flow out to the outside (the server rack 100 side).

[0053] In the present embodiment, the upper heat exchange core 310 has a tube 313, and the lower heat exchange core 320 has a tube 323. Then, as shown in FIGS. 4 and 5, the heat exchanger 30 includes, as the inflow parts 315, 325, an upper inflow part 315 connected to the tube 313 of the upper heat exchange core 310 and a lower inflow part 325 connected to the tube 323 of the lower heat exchange core 320, which are separated from each other. The heat exchanger 30 includes, as the outflow parts 316, 326, an upper outflow part 316 connected to the tube 313 of the upper heat exchange core 310 and a lower outflow part 326 connected to the tube 323 of the lower heat exchange core 320, which are separated from each other.

[0054] In the upper heat exchange core 310, each of the tubes 313 has its upstream end connected to the upper inflow section 315 so as to branch off in parallel from the upper inflow section 315. And each of the tubes 313 in the upper heat exchange core 310 has its downstream end connected to the upper outflow section 316. Similarly, in the lower heat exchange core 320, each of the tubes 323 has its upstream end connected to the lower inflow section 325 so as to branch off in parallel from the lower inflow section 325. And each of the tubes 323 in the lower heat exchange core 320 has its downstream end connected to the lower outflow section 326.

[0055] Specifically, the upper inflow section 315 is connected to an upper inlet pipe 315P having an inlet 315a for the heat medium and a plurality of upper first relay pipes 315b. The upper outflow section 316 is connected to a plurality of upper second relay pipes 316a and an upper outlet pipe 316P having an outlet 316b for the heat medium. The plurality of upper first relay pipes 315b are connected to the upstream ends of the corresponding tubes 313. The plurality of upper second relay pipes 316a are connected to the downstream ends of the corresponding tubes 313. The plurality of upper first relay pipes 315b and the plurality of upper second relay pipes 316a are arranged side by side in the vertical direction, and the plurality of tubes 313 to which they are connected are also arranged side by side in the vertical direction.

[0056] With the above connection mode, in the upper heat exchange core 310, the heat medium flowing into the upper inflow section 315 from the inlet 315a flows into each tube 313 through each upper first relay pipe 315b from the upper inflow section 315. And the heat medium flowing out from the downstream end of each tube 313 flows into the upper outflow section 316 through each upper second relay pipe 316a and can flow out from the outlet 316b of the upper outflow section 316.

[0057] Similarly, in the lower inlet portion 325, a lower inlet pipe 325P having an inlet 325a for the heat medium and a plurality of lower first relay pipes 325b are connected. In the lower outlet portion 326, a plurality of lower second relay pipes 326a and a lower outlet pipe 326P having an outlet 326b for the heat medium are connected. The plurality of lower first relay pipes 325b are connected to the upstream ends of the corresponding tubes 323. The plurality of lower second relay pipes 326a are connected to the downstream ends of the corresponding tubes 323. The flow of the heat medium on the lower side is the same as the flow of the heat medium on the upper side described above.

[0058] In the present embodiment, the inlets 315a, 325a for the heat medium in the upper inlet portion 315 and the lower inlet portion 325 and the outlets 316b, 326b for the heat medium in the upper outlet portion 316 and the lower outlet portion 326 open in the direction from the second surface 30B toward the first surface 30A. The upper inlet pipe 315P, the upper outlet pipe 316P, the lower inlet pipe 325P, and the lower outlet pipe 326P extend in the direction from the second surface 30B toward the first surface 30A. In this case, by suppressing the lateral protrusion of the inlet portion and the outlet portion of the heat medium, it is advantageous in terms of suppressing the overall size of the heat exchanger 30 and securing the area of the heat exchange core 30C. Note that the inlets 315a, 325a and the outlets 316b, 326b may open in the direction from the first surface 30A toward the second surface 30B. Further, the inlets 315a, 325a for the heat medium in the upper inlet portion 315 and the lower inlet portion 325 are formed on the lower side of the corresponding heat exchange core. The outlets 316b, 326b for the heat medium in the upper outlet portion 316 and the lower outlet portion 326 are formed on the upper side of the corresponding heat exchange core. In this case, the flow path lengths of the heat medium branched in parallel become uniform, and uniform cooling of the entire heat exchange core becomes possible.

[0059] As shown in FIG. 5, the upper inflow portion 315 and the lower inflow portion 325 are each a tubular body. The upper inflow portion 315 and the lower inflow portion 325 are located laterally on one side portion of the heat exchange core 30C and closer to the second surface 30B. The upper inflow portion 315 and the lower inflow portion 325 extend in the vertical direction, in other words, in the direction in which the upper heat exchange core 310 and the lower heat exchange core 320 are adjacent to each other. Here, the upper inflow portion 315 and the lower inflow portion 325 are arranged so as to be displaced in the direction from the first surface 30A toward the second surface 30B. Further, when viewed in the direction from the first surface 30A toward the second surface 30B, the lower part of the upper inflow portion 315 is arranged so as to overlap the upper part of the lower inflow portion 325 (see also FIG. 4). In other words, the upper end of the lower inflow portion 325 is located above the lower end of the upper inflow portion 315, and the upper part of the lower inflow portion 325 including the upper end of the lower inflow portion 325 overlaps the upper inflow portion 315.

[0060] Similarly, the upper outflow portion 316 and the lower outflow portion 326 are each a tubular body. The upper outflow portion 316 and the lower outflow portion 326 are located laterally on one side portion of the heat exchange core 30C and closer to the first surface 30A. The upper outflow portion 316 and the lower outflow portion 326 extend in the vertical direction. The upper outflow portion 316 and the lower outflow portion 326 are also arranged so as to be displaced in the direction from the first surface 30A toward the second surface 30B. Further, when viewed in the direction from the first surface 30A toward the second surface 30B, the lower part of the upper outflow portion 316 is arranged so as to overlap the upper part of the lower outflow portion 326.

[0061] In the present embodiment, as described above, the upper inflow portion 315 and the lower inflow portion 325 are arranged so as to be displaced in the direction from the first surface 30A toward the second surface 30B. Also, the upper outflow portion 316 and the lower outflow portion 326 are arranged so as to be displaced in the direction from the first surface 30A toward the second surface 30B. In this case, while avoiding undesired interference between members, it becomes possible to bring the upper heat exchange core 310 and the lower heat exchange core 320 closer to each other in the vertical direction, which is advantageous in terms of suppressing the overall size and ensuring the area of the heat exchange core 30C.

[0062] Also, in the present embodiment, as shown in FIG. 5, in the direction from the first surface 30A toward the second surface 30B, the positions of the upstream ends of the tubes 313 of the upper heat exchange core 310 and the positions of the upstream ends of the tubes 323 of the lower heat exchange core 320 are the same. On the other hand, as described above, the upper inflow portion 315 and the lower inflow portion 325 are displaced in the direction from the first surface 30A toward the second surface 30B.

[0063] Here, the upper first relay pipe 315b connected to the upper inflow portion 315 is formed in an arc or substantially L-shaped tubular form, and the lower first relay pipe 325b is formed in a straight tubular form. The upper inflow portion 315 is located closer to the first surface 30A than the lower inflow portion 325, and the arc or substantially L-shaped upper first relay pipe 315b approaches the upstream end of the tube 313 while advancing in the direction from the first surface 30A toward the second surface 30B, thereby connecting to the tube 313. The lower inflow portion 325 is positioned to face the upstream ends of the tubes 323 of the lower heat exchange core 320 and is connected to the upstream ends of the tubes 323 at the shortest distance by the straight tubular lower first relay pipe 325b. Thereby, without shifting the positions of the upstream ends of the tubes 313 of the upper heat exchange core 310 and the positions of the upstream ends of the tubes 323 of the lower heat exchange core 320, the fluid connection between the tubes 313 of the upper heat exchange core 310 and the upper inflow portion 315, and the fluid connection between the tubes 323 of the lower heat exchange core 320 and the lower inflow portion 325 are ensured.

[0064] On the one hand, the upper-stage second relay pipe 316a connected to the upper-stage outflow portion 316 is formed in a straight tubular shape, and the lower-stage second relay pipe 326a is formed in an arc or substantially L-shaped tubular shape. Thereby, without shifting the positions of the downstream ends of the respective tubes 313 of the upper-stage heat exchange core 310 and the positions of the downstream ends of the respective tubes 323 of the lower-stage heat exchange core 320, the fluid connection between each tube 313 of the upper-stage heat exchange core 310 and the upper-stage outflow portion 316, and the fluid connection between each tube 323 of the lower-stage heat exchange core 320 and the lower-stage outflow portion 326 are ensured. In the above connection mode, it becomes possible to make the structures of the upper-stage heat exchange core 310 and the lower-stage heat exchange core 320 common, which is advantageous in terms of ease of manufacture. Further, the occurrence of a difference in heat exchange performance between the upper and lower stages is suppressed, and effective heat exchange becomes possible.

[0065] Also, FIG. 6 is a top view of the heat exchange core 30C (upper-stage heat exchange core 310) in the heat exchanger 30 shown in FIG. 5. FIG. 6 shows the plate fins 314 provided in the upper-stage heat exchange core 310. The plate fins 314 extend parallel to the direction from the first surface 30A toward the second surface 30B and are arranged at intervals in the direction orthogonal to the said direction. The tube 313 extends while meandering from the second surface 30B side toward the first surface 30A side while passing through a plurality of plate fins 314 and contacts the plate fins 314. Specifically, the tube 313 passes through the plate fins 314 in a direction orthogonal to the plate fins 314. In the present embodiment, a plurality of plate fins 314 are provided such that the heat exchange surfaces (two surfaces facing each other in the thickness direction) are parallel in the vertical direction. As shown in FIG. 4, plate fins 324 similar to the plate fins 314 are also provided in the lower-stage heat exchange core 320.

[0066] As described above, the upper inflow portion 315 and the lower inflow portion 325 are arranged at positions closer to the second surface 30B. The upper outflow portion 316 and the lower outflow portion 326 are arranged at positions closer to the first surface 30A. Here, the tubes 313 and 323 each extend from the second surface 30B side toward the first surface 30A side, meandering in the left - right direction in this example. Thereby, in the heat exchanger 30, the heat medium flows from the second surface 30B side toward the first surface 30A side in each of the tubes 313 and 323. On the other hand, air flows from the first surface 30A side toward the second surface 30B side by the driving of the blower 20. That is, the heat exchanger 30 is configured as a counter - flow type heat exchanger that causes the heat medium and air to flow in opposite directions to each other for heat exchange.

[0067] FIG. 7 is a view of the upper heat exchange core 310 shown in FIG. 6 with the plate fins 314 removed. FIG. 8 is a cross - sectional view taken along line VIII - VIII of FIG. 7. Hereinafter, the shape of the tube 313 will be described in detail with reference to FIGS. 6 to 8.

[0068] As shown in FIGS. 6 and 7, the tube 313 forms a meandering shape by alternately and sequentially connecting straight - line - extending main flow path elements 313a and U - shaped return flow path elements 313b. The plurality of main flow path elements 313a are arranged in a parallel state and aligned in the direction in which air flows by the driving of the blower 20. The main flow path element 313a located most upstream in the direction in which air flows constitutes the first surface 30A, and the main flow path element 313a located most downstream in the direction in which air flows constitutes the second surface 30B. The heat exchange core 30C has a substantially rectangular parallelepiped shape, and the first surface 30A and the second surface 30B correspond to two opposite surfaces in the substantially rectangular parallelepiped shape.

[0069] The main flow path element 313a that constitutes the second surface 30B connects the end opposite to the end connected to the return flow path element 313b to the upper - stage first relay pipe 315b. The main flow path element 313a that constitutes the first surface 30A connects the end opposite to the end connected to the return flow path element 313b to the upper - stage second relay pipe 316a.

[0070] Also, referring to FIG. 8, when looking in the direction from the first surface 30A to the second surface 30B (from left to right in FIG. 8), at least a part of two adjacent main flow path elements 313a connected by the folded flow path element 313b do not overlap. Specifically, in the present embodiment, two adjacent main flow path elements 313a connected by the folded flow path element 313b are separated by a distance d1 in the vertical direction, and when looking in the direction from the first surface 30A to the second surface 30B, they do not entirely overlap. Also, between two adjacent tubes 313 in the vertical direction, the main flow path element 313a of one tube 313 that is close to the other and the main flow path element 313a of the other tube 313 are also separated by a distance d2 in the vertical direction.

[0071] When adopting the arrangement of the main flow path elements 313a as described above, air can easily come into contact with each main flow path element 313a, which can be advantageous in terms of improving heat exchange efficiency and can suppress an excessive increase in pressure loss. Note that the tubes 323 in the lower heat exchange core 320 also have the same shape as the tubes 313.

[0072] Also, in the present embodiment, plate fins 314 and 324 are used as fins in the heat exchanger 30, but corrugated fins or disc-shaped erosive fins may also be used. However, in the present embodiment, plate fins are adopted from the viewpoint of suppressing an excessive increase in pressure loss.

[0073] (Connection mode between the exhaust heat device and the server rack) Hereinafter, with reference to FIG. 9, the connection mode between the exhaust heat device 1 and the server rack 100 will be described. The exhaust heat device 1 includes a first pump 41 and a second pump 42 for circulating a heat medium. The first pump 41 and the second pump 42 may be, for example, centrifugal pumps driven by an electric motor, but their types are not particularly limited.

[0074] The first pump 41 is connected to the inlet 315a of the upper inflow section 315 that is connected to the upper heat exchange core 310. The second pump 42 is connected to the inlet 325a of the lower inflow section 325 that is connected to the lower heat exchange core 320. That is, in the present embodiment, the heat medium is supplied to the upper heat exchange core 310 and the lower heat exchange core 320 from separate pumps 41 and 42. Thereby, the loads on the respective pumps 41 and 42 can be reduced. In particular, in the present embodiment, since the upper heat exchange core 310 and the lower heat exchange core 320 overlap vertically, if one pump is used, a large amount of power may be required to ensure the necessary head, and thus the energy-saving effect of separating the pumps is significant. However, the heat medium may be supplied to the entire heat exchange core 30C from one pump.

[0075] The heat medium that has flowed into the tube 313 from the upper inflow section 315 flows while meandering from the second surface 30B side toward the first surface 30A side, and flows out from the outlet 316b. The heat medium that has flowed into the tube 323 from the lower inflow section 325 flows while meandering from the second surface 30B side toward the first surface 30A side, and flows out from the outlet 326b. Then, the heat medium that has flowed out from the outlets 316b and 326b merges and then flows into the server rack 100.

[0076] The server rack 100 has a plurality of cooling channels 110 that receive and circulate the heat medium after exchanging heat with air, and returns the heat medium flowing out of the cooling channels 110 to the exhaust heat device 1. The heat medium flowing through the cooling channels 110 takes heat from the server 102. Then, the heat medium flowing out of the cooling channels 110 is sucked by the first pump 41 and the second pump 42, returns to the exhaust heat device 1, and is cooled again.

[0077] In FIG. 9, the arrow α indicates the direction of the air flowing due to the drive of the blower 20. The arrow β indicates the direction of the heat medium flowing from the second surface 30B side toward the first surface 30A side in the upper heat exchange core 310 and the lower heat exchange core 320. The air and the heat medium perform heat exchange in a counterflow manner.

[0078] In the server cooling system S according to the embodiment described above, the waste heat device 1 includes an air-cooled heat exchanger 30 having a heat exchange core 30C including a first surface 30A and the opposite second surface 30B, and a plurality of blowers 20 provided adjacent to the second surface 30B and configured to flow air such that the air as a gas passes from the first surface 30A to the second surface 30B by the rotation of the impellers. The heat exchange core 30C has a plurality of tubes 313, 323 through which a heat medium that exchanges heat with the air flows. The tubes 313, 323 each extend while meandering from the second surface 30B side toward the first surface 30A side, and the heat medium flows from the second surface 30B side toward the first surface 30A side in each of the tubes 313, 323.

[0079] In this configuration, the air and the heat medium perform heat exchange in a countercurrent flow manner in the heat exchange core 30C, so that the entire tubes 313, 323 and the air uniformly exchange heat, thereby improving the heat exchange efficiency. Also, by using a plurality of blowers 20, the load on each blower for obtaining a desired cooling capacity can be suppressed. As a result, the power, noise, and size of the heat exchange core of the blower for obtaining a desired cooling capacity can be suppressed. Further, by flowing the heat medium through the plurality of tubes 313, 323, the overall flow path length and the complexity of the flow path shape of the tubes 313, 323 can be suppressed. Thereby, the power of the pump for flowing the heat medium can be suppressed, and the power consumption of the pump for obtaining a desired cooling capacity can be suppressed. As a result, the COP can be improved. Also, by adopting air cooling, the introduction cost can be suppressed, and since the power of the blower for obtaining a desired cooling capacity can be suppressed as described above, the scattering of dust and the like can be suppressed. Therefore, efficient cooling can be suitably realized while suppressing the introduction cost and the device occupation space.

[0080] Further, the heat exchanger 30 has inlet portions 315, 325 that receive a heat medium from the outside and allow it to flow into the tubes 313, 323. And the tubes 313, 323 are respectively connected to the inlet portions 315, 325 so as to branch off in parallel from appropriate positions of the inlet portions 315, 325. In this case, by allowing the heat medium to flow into the corresponding plurality of tubes 313, 323 in parallel from the inlet portions 315, 325, the power of the pumps (41, 42) for flowing the heat medium can be effectively suppressed, and the structure of the inflow path of the heat medium into the tubes 313, 323 can be simplified.

[0081] Further, the plurality of blowers 20 are arranged in a state where the extension line of the rotation axis Ax of the impeller 21 is orthogonal to the second surface 30B, and the tube 313 forms a meandering shape by alternately and sequentially connecting a straight main flow path element 313a and a U-shaped return flow path element 313b. And the adjacent main flow path elements 313a connected by the return flow path element 313b do not overlap at least partially when viewed in the direction from the first surface 30A to the second surface 30B. In this case, since air easily comes into contact with each main flow path element 313a, the heat exchange efficiency is improved, and the power of the blower 20 can be effectively suppressed. Note that the tube 323 also has the same structure as the tube 313.

[0082] Further, the heat exchanger 30 has a plurality of plate fins 314, 324 that extend parallel to the direction from the first surface 30A to the second surface 30B and are arranged in a direction orthogonal to the direction from the first surface 30A to the second surface 30B, in this example, the horizontal direction. And the tubes 313, 323 extend while meandering from the second surface 30B side toward the first surface 30A side while passing through the plate fins 314, 324 and come into contact with the plate fins 314, 324. In this case, the heat exchange efficiency is improved by heat dissipation from the plate fins 314, 324, and in particular, since the plate fins 314, 324 extend parallel to the axial flow direction, the pressure loss can be suppressed, and the power of the blower 20 can be effectively suppressed.

[0083] In addition, the plurality of blowers 20 are arranged in a state of multiple rows and multiple columns. In this case, even if some of the blowers 20 fail, the blowing function can be effectively maintained, and a decrease in the cooling performance can be suppressed. Also, compared to a configuration in which one blower is provided to cover a wide range of the heat exchange core 30C, the power required to obtain a desired air volume can be suppressed, and a large effective range related to the heat exchange of the heat exchange core 30C can be ensured. Thereby, the power of the blower 20 required to obtain a desired cooling capacity can be effectively suppressed, and the cooling efficiency can be improved.

[0084] Further, the heat exchange core 30C includes an upper heat exchange core 310 and a lower heat exchange core 320, and the upper heat exchange core 310 is stacked on the lower heat exchange core 320 from above. The heat exchanger 30 includes, as inflow portions 315, 325, an upper inflow portion 315 connected to the tube 313 in the upper heat exchange core 310 and a lower inflow portion 325 connected to the tube 323 in the lower heat exchange core 320. And the upper inflow portion 315 and the lower inflow portion 325 each extend in the vertical direction. And the upper inflow portion 315 and the lower inflow portion 325 are arranged so as to be displaced in the direction from the first surface 30A to the second surface 30B, and when viewed in the direction from the first surface 30A to the second surface 30B, the lower part of the upper inflow portion 315 overlaps the upper part of the lower inflow portion 325.

[0085] In this case, since the heat medium can be branched from the two pumps 41, 42 and supplied to the upper heat exchange core 310 and the lower heat exchange core 320, the power of the pumps 41, 42 can be suppressed. Also, with the arrangement in which the lower part of the upper inflow portion 315 overlaps the upper part of the lower inflow portion 325, while suppressing the occupied range of the entire heat exchanger 30, the size of the entire heat exchange core 30C can be ensured to be large, thereby improving the heat exchange efficiency.

[0086] (Condition setting example) Hereinafter, an example of a specific usage mode of the above-described server cooling system S will be described. The inventor of the present invention presumes that a server rack with a heat generation amount of about 150 kW per unit will be introduced in large numbers in future data centers. And the above-described server cooling system S can be configured to function extremely effectively at a cooling capacity of 150 kW or in the vicinity thereof. Specifically, by setting the following conditions (1) to (3) for the exhaust heat device 1, it becomes possible to cause the exhaust heat device 1 to perform cooling at 150 kW or in the vicinity thereof with an extremely high COP (Coefficient Of Performance).

[0087] · Condition (1): The areas of the first surface 30A and the second surface 30B of the heat exchange core 30C are each set to be 1.5 m 2 or more and 1.7 m 2 or less. · Condition (2): The air volume of the gas (air) flowing through the plurality of blowers 20 is set to be 345 m 3 / min or more and 375 m 3 / min or less. · Condition (3): The heat medium is selected and the flow rate of the heat medium is set so that the value (C·L) obtained by multiplying the specific heat C (kJ / kg·K) of the heat medium at 20°C to 40°C by the flow rate L (L / min) of the heat medium is between 250 and 320.

[0088] With the above conditions, the server cooling system S can output a cooling capacity of 140 kW or more and 160 kW or less with a COP of 15 or more. The inventor of the present case has confirmed more specifically that the server cooling system S can output a cooling capacity of 140 kW or more and 160 kW or less with an average COP of 20 or more and at least a COP of 15 or more even if there are fluctuations due to various conditions.

[0089] When the condition of the above condition (1) is set, the fin size that can be installed and the size of the heat exchange portion are generally determined. Desirably, the total of the heat exchange areas of the plate fins 314 and 324 provided in the heat exchanger 30 and the heat exchange areas of the tubes 313 and 323 is 600 m 2It is good to set as above. The heat exchange surfaces of the plate fins 314 and 324 mean two surfaces of the plate fins 314 and 324 that face each other in the thickness direction. The heat exchange surfaces of the tubes 313 and 323 mean the outer surfaces of the tubes 313 and 323 that are exposed to the outside. The sum of the areas of both of these is determined by adding the value obtained by multiplying the total area value of the above two surfaces of the plate fins 314 and 324 by the total number of the plate fins 314 and 324 and the surface area value of the outer surface of the tubes 313 and 323 excluding the connection parts with the plate fins 314 and 324. Also, the outer diameter D of the tubes 313 and 323 may be 8 mm or more and 20 mm or less. For example, the interval between the tubes 313 and 323 adjacent in the vertical direction in FIG. 5 may be 0.5D or more and 0.45D or less.

[0090] The air volume determined under the conditions of the above condition (2) is not an excessively large air volume and is a beneficial value from the viewpoint of power suppression. In addition to this, it is also desirable from the viewpoints of suppressing noise and scattering of dust. The air volume of the gas (air) flowed by the plurality of blowers 20 in the condition (2) is determined by the total value of the air volumes set for each blower 20.

[0091] Also, in addition to the above conditions (1) to (3), preferably, the heat exchange core 30C is configured such that the pressure loss when air with a wind speed of 5.5 m / s passes through it is 5 Pa or less.

[0092] FIG. 10 shows a table explaining a specification example of a server cooling system S that outputs a cooling capacity of 150 kW while satisfying the above conditions (1) to (3) and using an aqueous polyethylene glycol solution having a specific heat of 3.841 (kJ / kg·K) at 40°C as a heat medium. In this specification example, when the server 102 in the server rack 100 is heated up to 70°C and generates a heat generation amount of 150 kW, the server 102 is cooled down to 40°C and 150 kW is absorbed. In the specification example of FIG. 10, cooling of 150 kW is realized with a COP of 15 or more.

[0093] In the knowledge of the present inventors, when attempting to perform 150 kW of cooling with a general cooling system used in conventional data centers, the COP is about 5 to 10. For this conventional system, the server cooling system S according to the present embodiment can output an equivalent cooling capacity with a COP of generally more than twice (in this example, 15 or more). The cooling capacity of such a server cooling system S greatly contributes to energy conservation.

[0094] Note that the heat medium circulated through the heat exchanger 30 is not particularly limited. For example, as the heat medium, a fluorine-based inert liquid having a specific heat of about 1.000 to 1.200 (kJ / kg·K) at 20°C may be used. In this case, the flow rate of the heat medium is set to about 195 to 320 (L / min). When the flow rate is made relatively large in this way, it can be expected that effective cooling can be achieved by increasing the number of flow paths or complicating the flow path shape of the server rack 100 and circulating a large amount of heat medium. Note that since the fluorine-based inert liquid has a relatively low viscosity, the pump power does not become excessively large. When using a heat medium with a relatively small specific heat in this way, it is preferable to set the heat medium cooling efficiency (LPM / kW), which is determined by dividing the flow rate (L / min: LPM) of the heat medium by the cooling capacity, to 1.4 or more. This heat medium cooling efficiency may be 1.4 or more and 1.6 or less, or may be 1.45 or more and 1.55 or less.

[0095] <Modification Example> Hereinafter, modification examples will be described. For the same configurations as those in the above-described embodiment in the following modification examples, the same reference numerals are given and duplicate descriptions are omitted.

[0096] (First Modification Example) FIG. 11 shows an exhaust heat device according to the first modification example. In this modification example, four blowers 20 are arranged in a vertical row. In the heat exchanger 30, the first pump 41 is connected to the upper stage side, and the second pump 42 is connected to the lower stage side. The use of a plurality of pumps is beneficial in a specification where the heat exchanger becomes long in the vertical direction.

[0097] (Second Modification Example) FIG. 12 shows an exhaust heat recovery device according to a second modification. In this modification, the heat exchange core 30C of the heat exchanger 30 does not have a multi-stage structure. The heat exchange core 30C is composed of only a portion corresponding to the upper heat exchange core 310. The plurality of blowers 20 are arranged adjacent to each other in a 4-row and 4-column state with respect to the heat exchange core 30C. In the above-described embodiment, the heat exchange core 30C is configured to connect the upper heat exchange core 310 and the lower heat exchange core 320. However, the heat exchange core 30C may be configured to connect three or more heat exchange core elements.

[0098] (Third Modification) FIG. 13 shows an exhaust heat recovery device according to a third modification. Specifically, FIG. 13 is a view of the inside of the exhaust heat recovery device along a horizontal direction orthogonal to the direction in which air, which is a gas, flows by the blower 20. The exhaust heat recovery device according to the third modification includes a first heat exchanger 30-1 and a second heat exchanger 30-2. The first heat exchanger 30-1 and the second heat exchanger 30-2 are separated from each other and not connected.

[0099] The first heat exchanger 30-1 and the second heat exchanger 30-2 are in the shape of a rectangular parallelepiped or a plate, and are arranged adjacent to each other vertically and form a V shape when viewed in the horizontal direction.

[0100] The first heat exchanger 30-1 and the second heat exchanger 30-2 are each configured with the upper heat exchange core 310 described in the above embodiment as the main part. In FIG. 13, the same reference numerals are given to the elements that are the same as the elements constituting the upper heat exchange core 310 among the elements constituting the first heat exchanger 30-1 and the second heat exchanger 30-2. Although not shown, the first heat exchanger 30-1 and the second heat exchanger 30-2 each extend parallel to the direction from the first surface 30A to the second surface 30B and have a plurality of plate fins 314 arranged in a direction orthogonal to the direction from the first surface 30A to the second surface 30B, in this example, the horizontal direction. And the tubes 313 in the first heat exchanger 30-1 and the second heat exchanger 30-2 are arranged so as to be arranged in the direction in which the first heat exchanger 30-1 and the second heat exchanger 30-2 incline. On the other hand, when the first heat exchanger 30-1 and the second heat exchanger 30-2 are arranged so as to form a V shape as in this modified example, the tubes 313 may be arranged in a matrix arrangement instead of a staggered arrangement as in the above-described embodiment, and suitable heat exchange can be performed. Therefore, a matrix arrangement may be adopted.

[0101] The plurality of blowers 20 are arranged adjacent to the first heat exchanger 30-1 (second surface 30B) and the second heat exchanger 30-2 (second surface 30B) which are arranged to form a V shape. The plurality of blowers 20 are arranged on the same plane. Specifically, a part of the plurality of blowers 20 is arranged adjacent to the first heat exchanger 30-1, and another part of the plurality of blowers 20 is arranged adjacent to the second heat exchanger 30-2. Although not shown in the figure, in this example, 16 blowers 20 arranged in 4 rows and 4 columns are arranged adjacent to the first heat exchanger 30-1, and 16 blowers 20 arranged in 4 rows and 4 columns are arranged adjacent to the second heat exchanger 30-2. More specifically, 16 blowers 20 which are a part of the plurality of blowers 20 are arranged adjacent to the first heat exchanger 30-1 in a state where the extension line of the rotation axis Ax of each impeller 21 intersects the second surface 30B of the heat exchange core 30C of the first heat exchanger 30-1. 16 blowers 20 which are another part of the plurality of blowers 20 are arranged adjacent to the second heat exchanger 30-2 in a state where the extension line of the rotation axis Ax of each impeller 21 intersects the second surface 30B of the heat exchange core 30C of the second heat exchanger 30-2. However, the number of blowers 20 to be used is not particularly limited.

[0102] In the example of FIG. 13, the first heat exchanger 30-1 and the second heat exchanger 30-2 are arranged to form an obtuse V shape, but they may be arranged to form an acute V shape, or the first heat exchanger 30-1 and the second heat exchanger 30-2 may be arranged without being symmetrically inclined.

[0103] Also, in FIG. 13, reference numerals L1 to L4 indicate a plurality of (four) blowers 20 arranged in the vertical direction and the distances from each blower 20 to the first heat exchanger 30-1 (its heat exchange core 30C). The closer to the bottom part of the V shape, the longer the distance from the blower 20 to the heat exchange core 30C, and the relationship is L1 > L2 > L3 > L4. Here, in the third modification example, the setting of the air volume of the air which is the gas flowing through the plurality of blowers 20 and / or the setting of the rotation speed of the plurality of blowers 20 are different according to the distance between each blower 20 and the first heat exchanger 30-1 adjacent to each blower 20.

[0104] Specifically, also in this modified example, each blower 20 has the same structure and the same size, and when basically the same power is applied, it is driven at the same rotational speed and outputs the same air volume. Here, in this modified example, the value of the power supplied to the blower 20 is changed according to the distance between the blower 20 and the first heat exchanger 30-1.

[0105] Specifically, when the first heat exchanger 30-1 is inclined with respect to the vertical direction as in this modified example and the rotation axis of the blower 20 is along the horizontal direction, the air flowing in the horizontal direction can flow obliquely in a direction orthogonal to the first surface 30A and the second surface 30B of the first heat exchanger 30-1 when passing through the first heat exchanger 30-1. At this time, the air flowing out from the second surface 30B of the first heat exchanger 30-1 may tend to flow with a component from the side of the blower 20 where the distance to the heat exchange core 30C is short to the side of the blower 20 where the distance is long as a whole. In this case, the proportion of the component of the air inclined with respect to the impeller 21 in the air sucked by the blower 20 increases, and there is a risk that the smooth flow of the air may be impaired. Therefore, for example, the air volume setting of the blower 20 may be performed so that the relationship of the air volume of the blower 20 with the distance to the heat exchange core 30C being L1 < the air volume of the blower 20 with the distance to the heat exchange core 30C being L2 < the air volume of the blower 20 with the distance to the heat exchange core 30C being L3 < the air volume of the blower 20 with the distance to the heat exchange core 30C being L4 holds. In other words, the rotational speed setting of the blower 20 may be performed so that the relationship of the rotational speed of the blower 20 with the distance to the heat exchange core 30C being L1 < the rotational speed of the blower 20 with the distance to the heat exchange core 30C being L2 < the rotational speed of the blower 20 with the distance to the heat exchange core 30C being L3 < the rotational speed of the blower 20 with the distance to the heat exchange core 30C being L4 holds. For example, according to such a setting, the air can easily pass through the first heat exchanger 30-1, and the cooling efficiency can be improved. In other words, the cooling efficiency can be improved by suppressing the pressure loss.

[0106] That is, in the case where the first heat exchanger 30-1 and the second heat exchanger 30-2 are arranged to form a V shape and the distances from each blower 20 to the heat exchanger are not constant, the air volume or rotational speed of the blower 20 with a relatively shorter distance to the heat exchange core 30C among the plurality of blowers 20 is increased with respect to the blower 20 with a longer distance to the heat exchange core 30C than the blower 20 with a relatively shorter distance, so that the air can flow smoothly. However, depending on the structure of the exhaust heat removal device, the air volume or rotational speed of the blower 20 with a shorter distance to the heat exchange core 30C among the plurality of blowers 20 may be decreased with respect to the blower 20 with a longer distance to the heat exchange core 30C, and this may be more advantageous in some cases.

[0107] (Fourth Modification Example) FIG. 14 shows an exhaust heat removal device according to the fourth modification example. Specifically, FIG. 14 is a view of the inside of the exhaust heat removal device. The exhaust heat removal device according to the fourth modification example includes the first heat exchanger 30-1 and the second heat exchanger 30-2, which are the same as those in the third modification example. However, it is different from the third modification example in that the first heat exchanger 30-1 and the second heat exchanger 30-2 are arranged adjacent to each other in the horizontal direction and form a V shape when viewed from above.

[0108] Also in FIG. 14, 16 blowers 20 arranged in four rows and four columns are arranged adjacent to the first heat exchanger 30-1, and 16 blowers 20 arranged in four rows and four columns are arranged adjacent to the second heat exchanger 30-2. Specifically, 16 blowers 20, which are part of the plurality of blowers 20, are arranged adjacent to the first heat exchanger 30-1 in a state where the extension line of the rotation axis Ax of each impeller 21 intersects the second surface 30B of the heat exchange core 30C of the first heat exchanger 30-1. 16 blowers 20, which are another part of the plurality of blowers 20, are arranged adjacent to the second heat exchanger 30-2 in a state where the extension line of the rotation axis Ax of each impeller 21 intersects the second surface 30B of the heat exchange core 30C of the second heat exchanger 30-2. However, the number of blowers 20 to be used is not particularly limited. Also, in the example of FIG. 14, the first heat exchanger 30-1 and the second heat exchanger 30-2 are arranged in an obtuse V shape, but they may be arranged in an acute V shape, or the first heat exchanger 30-1 and the second heat exchanger 30-2 may be arranged without being symmetrically inclined. Also, although not shown, the first heat exchanger 30-1 and the second heat exchanger 30-2 each extend parallel to the direction from the first surface 30A to the second surface 30B and have a plurality of plate fins 314 arranged in the direction orthogonal to the direction from the first surface 30A to the second surface 30B, which is the horizontal direction in this example. And the tubes 313 in the first heat exchanger 30-1 and the second heat exchanger 30-2 are arranged such that the first heat exchanger 30-1 and the second heat exchanger 30-2 are arranged side by side in the vertical direction.

[0109] And in FIG. 14, reference numerals L1’ to L4’ indicate a plurality of (four) blowers 20 arranged in the horizontal direction and the distances from each blower 20 to the first heat exchanger 30-1 (its heat exchange core 30C). The closer to the bottom of the V shape, the longer the distance from the blower 20 to the heat exchange core 30C, and the relationship is L1’>L2’>L3’>L4’. Also in the fourth modification, the setting of the air volume of the air, which is the gas flowing through the plurality of blowers 20, and / or the setting of the rotational speed of the plurality of blowers 20 are different according to the distance between each blower 20 and the adjacent first heat exchanger 30-1.

[0110] Specifically, also in this modified example, each blower 20 has the same structure and the same size, and when basically the same power is applied, it is driven at the same rotational speed and outputs the same air volume. And also in this modified example, the value of the power supplied to the blower 20 is changed according to the distance between the blower 20 and the first heat exchanger 30-1.

[0111] Specifically, when the rotation axis of the blower 20 is along the horizontal direction as in this modified example and the first heat exchanger 30-1 is inclined with respect to the direction orthogonal to the rotation axis of the blower 20 in the horizontal plane, the air flowing in the horizontal direction can flow obliquely in the direction orthogonal to the first surface 30A and the second surface 30B of the first heat exchanger 30-1 when passing through the first heat exchanger 30-1. At this time, the air flowing out from the second surface 30B of the first heat exchanger 30-1 can generally tend to flow with a component from the side of the blower 20 where the distance to the heat exchange core 30C is shorter to the side of the blower 20 where the distance is longer. When the plate fins 314 extend in a direction parallel to the direction from the first surface 30A to the second surface 30B and are arranged horizontally as in the configuration of this modified example, such a tendency is particularly likely to occur. In this case, the ratio of the component of the air inclined with respect to the impeller 21 in the air sucked by the blower 20 increases, and there is a risk that the smooth flow of the air may be impaired.

[0112] Therefore, also in this modified example, for example, the air volume setting of the blower 20 may be performed so that the air volume of the blower 20 with the distance to the heat exchange core 30C being L1’ < the air volume of the blower 20 with the distance to the heat exchange core 30C being L2’ < the air volume of the blower 20 with the distance to the heat exchange core 30C being L3’ < the air volume of the blower 20 with the distance to the heat exchange core 30C being L4’. In other words, the rotational speed setting of the blower 20 may be performed so that the rotational speed of the blower 20 with the distance to the heat exchange core 30C being L1’ < the rotational speed of the blower 20 with the distance to the heat exchange core 30C being L2’ < the rotational speed of the blower 20 with the distance to the heat exchange core 30C being L3’ < the rotational speed of the blower 20 with the distance to the heat exchange core 30C being L4’. In this case, the same effect as the effect described in the third modified example can be obtained.

[0113] (Fifth Modification Example) Figs. 15 and 16 show an exhaust heat recovery device according to the fifth modification example. Specifically, Fig. 15 shows the appearance of the exhaust heat recovery device according to the fifth modification example, and Fig. 16 is a cross-sectional view taken along line XVI-XVI of Fig. 15. Similar to the fourth modification example, the exhaust heat recovery device according to the fifth modification example includes a first heat exchanger 30-1 and a second heat exchanger 30-2 that are arranged to form a V shape when viewed from above. However, it is different from the fourth modification example in that the first heat exchanger 30-1 and the second heat exchanger 30-2 are arranged to form an acute V shape.

[0114] In this modification example, 40 blowers 20 arranged in 20 rows and 2 columns are arranged adjacent to the first heat exchanger 30-1, and 40 blowers 20 arranged in 20 rows and 2 columns are arranged adjacent to the second heat exchanger 30-2. Specifically, 40 blowers 20 arranged in 20 rows and 2 columns, which are part of the plurality of blowers 20, are arranged adjacent to the first heat exchanger 30-1 in a state where the extension line of the rotation axis Ax of each impeller 21 intersects the second surface 30B of the heat exchange core 30C of the first heat exchanger 30-1. 40 blowers 20 arranged in 20 rows and 2 columns, which are another part of the plurality of blowers 20, are arranged adjacent to the second heat exchanger 30-2 in a state where the extension line of the rotation axis Ax of each impeller 21 intersects the second surface 30B of the heat exchange core 30C of the second heat exchanger 30-2. Each blower 20 is arranged on the same plane and held by the housing 10. The number of blowers 20 to be used is not particularly limited, but it is preferable to provide blowers arranged in multiple rows and multiple columns for each heat exchanger.

[0115] In Fig. 16, reference numerals L1’’ and L2’’ indicate a plurality of (two) blowers 20 arranged horizontally and the distances from each blower 20 to the first heat exchanger 30-1 (its heat exchange core 30C). The closer to the V-shaped bottom portion, the longer the distance from the blower 20 to the heat exchange core 30C, and the relationship is L1’’>L2’’. Also in the fifth modification, the setting of the air volume of the air, which is the gas flowing through the plurality of blowers 20, and / or the setting of the rotation speed of the plurality of blowers 20 are different according to the distance between each blower 20 and the adjacent first heat exchanger 30-1.

[0116] Specifically, the air volume of the blower 20 with the distance to the heat exchange core 30C being L1’’ is set such that the relationship is the air volume of the blower 20 with the distance to the heat exchange core 30C being L2’’. In other words, the rotation speed of the blower 20 with the distance to the heat exchange core 30C being L1’’ is set such that the relationship is the rotation speed of the blower 20 with the distance to the heat exchange core 30C being L2’’.

[0117] That is, also in this modification, by increasing the air volume or rotation speed of the blower 20 with a relatively shorter distance to the heat exchange core 30C among the plurality of blowers 20 compared to the blower 20 with a longer distance to the heat exchange core 30C than this blower 20 with a relatively shorter distance, air can flow smoothly. When the first heat exchanger 30-1 and the second heat exchanger 30-2 are arranged so as to form an acute V shape, such a setting of the air volume or rotation speed can be particularly effective.

[0118] In the third to fifth modifications, the first heat exchanger 30-1 and the second heat exchanger 30-2 arranged to form a V shape are arranged such that the bottom portion of the V shape faces away from the blower 20 side. Instead of such a layout, the first heat exchanger 30-1 and the second heat exchanger 30-2 may be arranged such that the bottom portion of the V shape faces the blower 20 side.

[0119] The above-described embodiments and modifications show an example for embodying the present invention, and the present invention can be implemented in various other forms. For example, various modifications, substitutions, omissions, or combinations thereof are possible without departing from the gist of the present invention. Forms with such modifications, substitutions, omissions, etc. are also included in the scope of the present invention and are included in the invention described in the claims and the equivalent scope thereof.

Explanation of Reference Numerals

[0120] S... Server cooling system, 1... Exhaust heat device, 10... Housing, 20... Blower, 21... Impeller, 22... Casing, 30... Heat exchanger, 30-1... First heat exchanger, 30-2... Second heat exchanger, 30A... First surface, 30B... Second surface, 30C... Heat exchange core, 310... Upper heat exchange core, 310A... Upper first surface, 310B... Upper second surface, 311... Upper frame, 313... Tube, 313a... Main flow path element, 313b... Return flow path element, 314... Plate fin, 315... Upper inflow portion (inflow portion), 315a... Inlet, 315P... Upper inlet pipe, 315b... Upper first relay pipe, 316... Upper outflow portion (outflow portion), 316a... Upper second relay pipe, 316b... Outlet, 316P... Upper outlet pipe, 320... Lower heat exchange core, 320A... Lower first surface, 320B... Lower second surface, 321... Lower frame, 323... Tube, 324... Plate fin, 325... Lower inflow portion (inflow portion), 325a... Inlet, 325P... Lower inlet pipe, 325b... Lower first relay pipe, 326... Lower outflow portion (outflow portion), 326a... Lower second relay pipe, 326b... Outlet, 326P... Lower outlet pipe, 41... First pump, 42... Second pump, 100... Server rack, 101... Rack body, 102... Server, 110... Refrigerant flow path

Claims

1. An air-cooled heat exchanger having a heat exchange core including a first surface and a second surface opposite the first surface, The system comprises a plurality of blowers that cause the gas to flow from the first surface to the second surface by the rotation of an impeller, The heat exchange core has a plurality of tubes through which a heat transfer medium to be exchanged with the gas flows. Each of the tubes extends in a meandering manner from the second surface to the first surface, and the heat transfer medium flows in each of the tubes from the second surface to the first surface. The tube forms a meandering shape by alternately connecting a main flow channel element that extends in a straight line and a U-shaped folded flow channel element. Multiple blowers are arranged such that the extension of the rotation axis of the impeller is perpendicular to the second surface. A heat dissipation device in which adjacent main flow elements connected by the aforementioned folded flow element do not overlap in at least part when viewed in the direction from the first surface to the second surface.

2. An air-cooled heat exchanger having a heat exchange core including a first surface and a second surface opposite the first surface, The system comprises a plurality of blowers that cause the gas to flow from the first surface to the second surface by the rotation of an impeller, The heat exchange core has a plurality of tubes through which a heat transfer medium to be exchanged with the gas flows. Each of the tubes extends in a meandering manner from the second surface to the first surface, and the heat transfer medium flows in each of the tubes from the second surface to the first surface. The heat exchanger has a plurality of plate fins that extend parallel to the direction from the first surface to the second surface and are arranged in a direction perpendicular to the direction from the first surface to the second surface. The tube extends in a meandering manner from the second surface side toward the first surface side, while penetrating a plurality of plate fins, and is in contact with the plate fins, in the heat dissipation device.

3. An air-cooled heat exchanger having a heat exchange core including a first surface and a second surface opposite the first surface, The system comprises a plurality of blowers that cause the gas to flow from the first surface to the second surface by the rotation of an impeller, The heat exchange core has a plurality of tubes through which a heat transfer medium to be exchanged with the gas flows. Each of the tubes extends in a meandering manner from the second surface to the first surface, and the heat transfer medium flows in each of the tubes from the second surface to the first surface. The heat exchanger has an inlet that receives the heat transfer medium from the outside and allows it to flow into the tube. Each of the aforementioned tubes branches in parallel from the inlet, The heat exchange core includes a first heat exchange core and a second heat exchange core, and the first heat exchange core and the second heat exchange core are arranged adjacent to each other. The heat exchanger includes, as the inlet section, an inlet section connected to the tube of the first heat exchange core, which is separated from the others, and an inlet section connected to the tube of the second heat exchange core, The inlet connected to the tube of the first heat exchange core and the inlet connected to the tube of the second heat exchange core each extend in a direction in which the first heat exchange core and the second heat exchange core are adjacent to each other. A heat dissipation device in which the inlet connected to the tube of the first heat exchange core and the inlet connected to the tube of the second heat exchange core are arranged such that they are offset in the direction from the first surface toward the second surface, and when viewed in the direction from the first surface toward the second surface, the end of the inlet connected to the tube of the first heat exchange core on the second heat exchange core side overlaps the end of the inlet connected to the tube of the second heat exchange core on the first heat exchange core side.

4. The heat dissipation device according to claim 3, wherein the inlet for the heat transfer medium at the inlet connected to the tube of the first heat exchange core and the inlet for the heat transfer medium at the inlet connected to the tube of the second heat exchange core open in a direction toward the second surface or in the opposite direction.

5. An air-cooled heat exchanger having a heat exchange core including a first surface and a second surface opposite the first surface, The system comprises a plurality of blowers that cause the gas to flow from the first surface to the second surface by the rotation of an impeller, The heat exchange core has a plurality of tubes through which a heat transfer medium to be exchanged with the gas flows. Each of the tubes extends in a meandering manner from the second surface to the first surface, and the heat transfer medium flows in each of the tubes from the second surface to the first surface. The heat dissipation device comprises two heat exchangers, The two heat exchangers are arranged to form a V-shape. A heat dissipation device comprising: a portion of the plurality of blowers arranged adjacent to one of the two heat exchangers such that the extension of the rotation axis of the impeller intersects with the second surface of one of the two heat exchangers; and a portion of the plurality of blowers arranged adjacent to the other of the two heat exchangers such that the extension of the rotation axis of the impeller intersects with the second surface of the other of the two heat exchangers.

6. The heat dissipation device according to claim 5, wherein the setting of the airflow volume of the gas flowed by the multiple blowers or the setting of the rotation speed of the multiple blowers differs depending on the distance between each blower and the adjacent heat exchanger.

7. The heat dissipation device according to any one of claims 1 to 6, wherein the multiple blowers are arranged in multiple rows and multiple columns.

8. A heat dissipation device according to any one of claims 1 to 6, The server rack is supplied with the heat transfer medium from the heat dissipation device, The server rack has a cooling channel that receives and circulates the heat transfer medium after heat exchange with the gas, and the server cooling system returns the heat transfer medium flowing out of the cooling channel to the heat dissipation device.

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