JP2008122058A - Radiator and cooling system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small and thin radiator with favorable heat radiating characteristics mountable in a small and thin apparatus such as a notebook PC, and also to provide a cooling system with superior cooling performance. <P>SOLUTION: The radiator has an inlet line and an outlet line for liquid to be cooled, and a plurality of passage units connected in between and in parallel with the inlet line and the outlet line with mutual intervals and forming a liquid passage returning from the inlet line to the outlet line, and the cooling system uses the radiator. By suitably determining the number of passage units and a passage cross-sectional area, a flow velocity of each passage unit is decreased, and the liquid to be cooled is effectively cooled. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radiator and a cooling system for cooling a passing liquid.

For example, a cooling system for a CPU (heat source) that generates heat has, as basic components, a cooling liquid jacket that contacts the CPU and takes heat away, a radiator, and a liquid pump that circulates the cooling liquid between the cooling liquid jacket and the radiator. Each element is downsized and highly reliable so that it can be mounted on a small device such as a notebook PC.
JP-A-6-97338 Japanese Patent Laid-Open No. 2003-8273 JP 2003-324174 A

  However, it is difficult to mount a conventionally known radiator on a small and thin device such as a notebook PC, or sufficient heat dissipation cannot be expected.

  An object of the present invention is to obtain a radiator that is small and thin and can be stored in a narrow space and has good heat dissipation. Another object of the present invention is to obtain a cooling system with excellent cooling performance.

  The radiator according to the present invention has an inlet line and an outlet line for the liquid to be cooled; a liquid flow path returning from the inlet line to the outlet line, connected in parallel between the inlet line and the outlet line. A plurality of flow path units to be formed.

  Specifically, each flow path unit is formed by, for example, stacking and joining a pair of flow path plates forming a liquid flow path bent at least once in a U shape, An inlet hole and an outlet hole which are connected to the line and the outlet line and constitute a part of the inlet line and the outlet line can be formed.

  A pair of flow path plates constituting each flow path unit is formed in a plane symmetric shape symmetrical with respect to the overlapping surface, and is formed in a planar U-shaped flow path recess and at one end and the other end of the flow path recess. It is preferable to provide the inlet hole and the outlet hole.

  In addition, a pair of flow path plates constituting each flow path unit is provided with a spacer portion protruding outward at the inlet hole and outlet hole portions, and the spacer portions of the overlapped flow path units are brought into contact with each other to flow. An air passage space can be formed in the remainder of the path unit.

  It is practical that the inlet holes and the outlet holes of the plurality of stacked flow path units communicate with each other, and the inlet line and the outlet line are connected to the inlet hole and the outlet hole, respectively.

  Further, the pair of flow path plates constituting each flow path unit contact each other when overlapped, apart from the spacer portion of the inlet hole portion and the outlet hole portion, and secure a space between the flow path units. The spacer protrusion can be formed integrally.

  The above radiator includes a fan that blows air toward the flow path unit of the radiator, a coolant jacket that contacts the heat source and takes heat of the heat source, and a liquid that circulates the coolant between the coolant jacket and the radiator. It can be used for a cooling system equipped with a pump. In the cooling system according to the present invention, the radiator is characterized in that the inlet line is disposed farther from the outlet line than the outlet line of the fan. The fan is a centrifugal fan that blows in the centrifugal direction, and when the air is blown toward the flow path unit, the fan is folded from the inlet line to the outlet line from one end side where the inlet line and the outlet line of the flow path unit are provided. It is characterized by being arranged in a posture where the air volume becomes large at the end side.

  The radiator according to the present invention has a plurality of flow path units connected in parallel and spaced apart from each other between an inlet line and an outlet line of a liquid to be cooled. Since the liquid flow path returning to the outlet line from the inlet line is provided, the liquid to be cooled from the inlet line can be diverted to each flow path unit and allowed to pass at a reduced flow speed, so that the cooling efficiency can be improved. According to a specific mode in which each flow path unit is configured by a pair of flow path plates, a small and thin radiator with high cooling efficiency can be obtained.

  As described above, the cooling system of the present invention uses a radiator capable of diverting the liquid to be cooled from the inlet line to each flow path unit and passing the liquid at a reduced flow rate. Can be obtained. In this cooling system, the radiator inlet line is farther from the fan outlet than the outlet line, so the liquid to be cooled from the inlet line can be efficiently cooled in the flow path to the outlet line, and the cooling efficiency Can be increased. Further, the fan is a centrifugal fan having a blower opening in a part of the centrifugal direction, and blows more air to the other end side where the inlet line and the outlet line of the flow path unit are folded back than the one end side provided with the inlet line and the outlet line. Therefore, the liquid to be cooled from the inlet line can be cooled more efficiently in the flow path leading to the outlet line, and the cooling efficiency can be increased.

  FIG. 9 is a conceptual diagram of a cooling system (water cooling system) according to the present invention, illustrating the CPU 1 as a heat source. The CPU 1 is in contact with a CPU jacket (coolant jacket) 10 as a heat receiving block. The coolant supplied from the liquid pump 12 to the CPU jacket 10 flows through the flow path in the CPU jacket 10 and removes heat from the CPU 1. The coolant heated by the CPU jacket 10 is cooled by receiving cooling air from the cooling fan 22 while flowing through the coolant flow path 21 in the radiator 20, returns to the liquid pump 12 again, and repeats this circulation.

  FIG. 1 is a diagram showing a basic concept of a radiator 20 according to the present invention. The inlet line 23 and the outlet line 24 for the liquid to be cooled are parallel to each other. The plurality of flow path units 30 are connected in parallel between the inlet line (inlet flow path) 23 and the outlet line (outlet flow path) 24 at intervals. That is, each flow path unit 30 includes an inlet hole 31 connected (communication) to the inlet line 23, an outlet hole 32 connected (communication) to the outlet line 24, and the inlet hole 31 and the outlet hole 32. The plurality of flow path units 30 in a stacked state are separated from each other at least in the coolant flow path 21 portion. The inlet line 23 and the outlet line 24 are respectively connected to the CPU jacket 10 and the liquid pump 12 in the example of the cooling system of FIG.

  The above radiator 20 can set the flow rate flowing through each flow path unit 30 to A / n, where A is the flow rate flowing through the inlet line 23 and the outlet line 24 and n is the number of flow path units 30. For this reason, even if the flow rate flowing through each flow path unit 30 is reduced, the total flow path cross-sectional area of all flow path units 30 is increased, so that a sufficient cooling effect can be obtained.

  2 to 8 show a more specific embodiment of the radiator 20. In the example of FIGS. 2 to 6, the flow path units 30 are stacked in five stages, and each flow path unit 30 has the same structure except for the lowermost flow path unit 30.

  Each flow path unit 30 is configured by a pair of flow path plates 34U and 34L that are joined together in an overlapping manner. The flow path plates 34U and 34L are made of, for example, a press-formed product of a metal material having excellent heat conductivity, and have a symmetrical shape (same single shape) with respect to the overlapping surface (laminated surface). 7 and 8 show the single shape of the flow path plate 34U (34L). The flow path plate 34U (34L) has an elongated shape, and has a flat U-shaped flow path recess 36 on a flat joint surface 35. An inlet hole 31 and an outlet hole 32 are formed at both ends of the U-shaped channel recess 36 (the end opposite to the U-shaped folded portion).

  The inlet hole 31 and the outlet hole 32 are formed in a spacer portion 37 and a spacer 38 portion formed on the flow path plate 34U (34L) by projecting outward from the U-shaped flow path recess 36 portion. Further, another spacer protrusion 39 having the same height as the spacer portion 37 (38) is formed in the flow path plate 34U (34L) so as to be positioned on the opposite side of the spacer portion 37 (38).

  The flow path plates 34U and 34L are overlapped with each other so that the flow path recess 36 faces outward, and the joint surfaces 35 are joined by brazing, for example. Then, the coolant flow path 21 is formed by the upper and lower U-shaped flow path recesses 36 protruding in opposite directions. As apparent from FIG. 5, the coolant flow path 21 has a flat shape. Also, the spacer portions 37 (38) of the upper and lower flow path units 30 are in contact with each other so that the inlet holes 31 and the outlet holes 32 of the upper and lower flow path units 30 communicate with each other. A part of 24 is configured. An inlet hole 31 (outlet hole 32) is not formed in the spacer portion 37 (38) of the flow path plate 34L below the lowermost flow path unit 30 (FIG. 6). In FIG. 7, the inlet hole 31 and the outlet hole 32 are drawn with chain lines, and the lowermost flow path plate 34 </ b> L can be obtained by not drilling the holes 31 and 32. When the spacer portions 37 (38) of the upper and lower flow path units 30 are in contact with each other, the spacer projections 39 of the upper and lower flow path units 30 are in contact with each other at the same time to form the U-shaped flow path recesses 36 ( A cooling air passage space S is formed between the coolant channels 21).

  The five-stage flow path units 30 superposed as described above are connected and coupled by the flow path block 40. The flow path block 40 includes an upper body 41 having an inlet line 23 and an outlet line 24, and a lower body 42 that holds the five-stage flow path unit 30 between the upper body 41. The upper body 41 is formed with a pair of annular recesses 43 that receive the spacer portions 37 (38) of the uppermost flow path unit 30. The annular recesses 43 and the O-ring 44 simultaneously with the spacer portions 37 (38). Is inserted to maintain liquid tightness (FIG. 6). The spacer leg 41S regulates the tightening distance between the upper body 41 and the lower body 42.

  Accordingly, in the radiator 20 described above, the liquid to be cooled supplied from the inlet line 23 is distributed to each flow path unit 30. That is, it is supplied from the inlet hole 31 of each flow path unit 30 to the coolant flow path 21 and returned from the outlet hole 32 to the outlet line 24. A cooling air passage space S is formed between the upper and lower flow path units 30, and the air passing through the space exchanges heat with the flow path plate 34 </ b> U (34 </ b> L) and covers the cooling air flow path 21. The cooling liquid can be cooled. In the flow path unit 30, it is possible to reduce the flow velocity so that sufficient cooling action is performed by appropriately setting the cross-sectional area of the flow path, and cooling can be performed by selecting the number of stacked layers of the flow path unit 30. The ability can be set freely.

  In the present embodiment, one U-shaped channel is formed in the channel unit 30 (channel plate 34U (34L)). However, an S-shaped channel or a plurality of folded channels can be formed. . Further, since the spacer protrusion 39 is provided on the opposite side of the spacer portion 37 (38) with respect to the length direction of the flow path plate 34U (34L), the distance between the flow path units 30 can be maintained in a balanced manner. However, spacer protrusions may be provided in another part, and the spacer protrusions 39 may be omitted as long as the interval between the flow path units 30 can be maintained.

  Next, a cooling system according to the present invention will be described with reference to FIGS.

  The cooling system L includes the above-described radiator 20, a cooling fan 22 that blows air toward the coolant flow path 21 of the radiator 20, and a CPU jacket (coolant jacket) 10 that abuts against the CPU 1 that is a heat source and takes heat away. The water cooling system includes a liquid pump 12 that circulates a coolant between the CPU jacket 10 and the radiator 20. The inlet line 23 and outlet line 24 for the liquid to be cooled are referred to as the outlet line 24 on the side closer to the cooling fan 22 and the inlet line 23 on the far side.

  The cooling fan 22 is a multi-blade centrifugal fan having a blower port 22a in a part of the centrifugal direction, and the blower port 22a is directed to the radiator 20, and one end of the radiator 20 provided with an inlet line 23 and an outlet line 24. It arrange | positions in the direction which ventilates more by the other end side 20b turned back from the inlet line 23 to the outlet line 24 rather than the side 20a. FIG. 10 is an external view showing the cooling fan 22, and FIG. 11 shows the air volume distribution of the cooling fan 22. This air volume distribution is obtained by measuring the wind speed at each position by setting a plurality of wind speed sensors S1 to S7 with the surface of the cooling fan 22 facing upward and changing the position in the vicinity of the air blowing port 22a (see FIG. 10). is there. At the time of this measurement, the rotation direction of the cooling fan 22 is counterclockwise, and the positions of the wind speed sensors S1 to S7 are expressed with the lower side (lower side in FIG. 10) of the air outlet 22a as zero. When the surface of the cooling fan 22 faces upward, the wind flows at a large angle of several tens of degrees from the lower left to the upper right of FIG. 10, and as is apparent from FIG. The wind speed is large on the upper side (upper side in FIG. 10) of FIG. 10, and the wind speed is lower on the lower side (lower side in FIG. 10) of the air blowing port 22a. In such a cooling fan having a different air volume depending on the position in the air blowing port 22a, when the front and back surfaces are reversed, the air volume distribution is also reversed accordingly. That is, in the state where the back surface of the cooling fan 22 faces upward, the wind flows at a large angle from the upper left to the lower right in FIG. The wind speed is reduced on the upper side of the opening 22a. In the present cooling system L, taking into account other reasons described later, the wind speed is small on the lower side of the blower port 22a facing the one end side 20a (the inlet line 23 and the outlet line 24 side) of the radiator 20, and the radiator 20 The surface of the cooling fan 22 is arranged facing upward so that the wind speed increases on the upper side in the figure of the air blowing port 22a facing the other end side 20b (turned side).

  Below, the cooling performance of this cooling system L (FIG. 9) is evaluated.

  FIG. 12 shows a configuration of an air cooling system A as a comparative example of the cooling system L. In the air cooling system A, when the CPU 1 is used as a heat source, the heat pipe 111 that takes heat from the CPU 1 through the CPU jacket 10 and the end of the heat pipe 111 opposite to the heat transfer unit 111a that contacts the CPU 1 (the heat radiating unit 111b). ) And a cooling fan 122 that blows air toward the radiator 120. A heat medium is enclosed in the heat pipe 111, and when this heat medium receives heat from the CPU 1 in the heat transfer section 111a, it boils and becomes a gas and moves to the heat radiating section 111b together with the radiator 20 in the heat radiating section 111b. When it is cooled, it condenses to become liquid and returns to the heat transfer section 111a, and thereafter, the CPU 1 is cooled by repeating this circulation. In the air cooling system A and the cooling system L, the same CPU 1 and cooling fans 22 and 122 as heat sources are used.

  In Table 1, the cooling performance of the cooling system L (Example) and the air cooling system A (comparative example) is compared and shown.

[Table 1]

  In Table 1, the first item a1 is the power [W] of the heat source (CPU1). The second item a2 is the size of the cooling fan, and is indicated by the internal dimension [mm × mm] of the blower opening. The third item a3 is the wind speed [m / s] when coming out from the air outlet of the cooling fan (power source DC5V), the fourth item a4 is the wind speed [m / s] when coming out of the radiator, and the fifth item a5. Is room temperature [Ta ° C.]. The sixth item a6 is the temperature [T ° C.] of the wind coming out of the radiator, and the seventh item a7 is the temperature [T ° C.] of the heat source (CPU 1). The eighth item a8 and the ninth item a9 are the temperatures of the liquid to be cooled on the inlet side and the outlet side of the CPU jacket 10 in the cooling system L, but in the air cooling system A, the heat transfer portion 111a (see FIG. 12) of the heat pipe 111. Is measured as the temperature at the outlet side of the CPU jacket 10. The tenth item a10 and the eleventh item a11 are the temperatures of the liquid to be cooled on the inlet side and the outlet side of the radiator 20 in the cooling system L, but in the air cooling system A, the heat pipe 111 inserted into the radiator 120 is used. The temperature closest to the heat radiating section (measurement point a10 in FIG. 12) is shown as the temperature on the inlet side of the radiator. The twelfth item a12 is the temperature difference [ΔT ° C.] between the inlet side and the outlet side of the CPU jacket 10 in the cooling system L, and the temperature difference [ΔT ° C.] between the CPU 1 and the heat transfer portion 111a of the heat pipe 111 in the air cooling system A. . The thirteenth item a13 is a temperature difference [ΔT ° C.] between the outlet side of the radiator 20 and the inlet side of the CPU jacket 10 in the cooling system L, and a temperature difference between the inlet side of the radiator 120 and the outlet side of the CPU jacket 10 in the air cooling system A. That is, it is the temperature difference [ΔT ° C.] between the heat transfer portion 111a and the heat radiating portion of the heat pipe 111. The fourteenth item a14 is the temperature difference [ΔT ° C.] between the inlet side and the outlet side of the radiator 20 in the cooling system L, and the fifteenth item a15 is the difference between the temperature of the air coming out of the radiators 20 and 120 and the room temperature [ΔT ° C.]. is there. The sixteenth item a16 is the thermal resistance value [° C / W] at the CPU jacket 10, the seventeenth item a17 is the thermal resistance value [° C / W] at the heat pipe 111, and the eighteenth item a18 is the heat at the radiators 20 and 120. The resistance value [° C./W], the nineteenth item a19 is the thermal resistance value [° C./W] in the entire system. The cooling performance can be evaluated by the magnitude of the thermal resistance value of the entire system. It can be said that the smaller the thermal resistance value, the better the cooling performance. The thermal resistance of the entire system can be calculated by (heat source temperature a7−room temperature a5) / heat source power a1.

  As is apparent from Table 1, the cooling system L has a thermal resistance value of 1.11 [° C./W] smaller than the thermal resistance value of air cooling system A of 1.73 [° C./W]. Also has excellent cooling performance.

  Next, Table 2 shows a cooling system L (example) in which the inlet line 23 of the liquid to be cooled is disposed on the side far from the cooling fan 22 and the outlet line 24 is disposed on the side near the cooling fan 22, and the outlet of the liquid to be cooled. The cooling performance of the second cooling system (comparative example) in which the line 24 is arranged on the side far from the cooling fan 22 and the inlet line 23 is arranged on the side close to the cooling fan 22 is shown in comparison. The second cooling system has the same configuration as the cooling system L shown in FIG. 9 except that the arrangement of the inlet line 23 and the outlet line 24 is different. Since items a1 to a16, a18, and a19 in Table 2 are the same as items a1 to a16, a18, and a19 in Table 1, the description thereof is omitted.

[Table 2]

  As is apparent from Table 2, the cooling system L (example) in which the inlet line 23 of the liquid to be cooled is disposed on the side far from the cooling fan 22 and the outlet line 24 is disposed on the side near the cooling fan 22 has a thermal resistance value. 0.97 [° C./W] is smaller than the thermal resistance value 0.99 [° C./W] of the second cooling system (comparative example), and the outlet line 24 of the liquid to be cooled is placed on the side far from the cooling fan 22. The cooling performance can be improved as compared with the case where the line 23 is disposed closer to the cooling fan 22.

  The difference in the cooling performance due to the difference in the arrangement mode of the inlet line 23 and the outlet line 24 is that the cooling system L that efficiently cools the cooling liquid by applying cold air having the lowest temperature to the outlet line 24 side (Example) On the other hand, in the second cooling system (comparative example), when the cooling liquid once cooled passes through the outlet line 24, the cooling efficiency hits the hot air heated by the hot cooling liquid passing through the inlet line 23. This is thought to be due to deterioration.

  Subsequently, in Table 3, a cooling system L in which the cooling fan 22 is arranged in a direction to blow more air to the other end side (turned side) 20b than the one end side (inlet line 23 and outlet line 24 side) 20a of the radiator 20 (implementation). The cooling performance of the example) is compared with the cooling performance of the third cooling system (comparative example) in which the cooling fan 22 is arranged in a direction in which more air is blown to the one end side 20a than the other end side 20b of the radiator 20. The third cooling system has the same configuration as the cooling system L of FIG. 9 except that the direction of the cooling fan 22 is different. The items a1 to a16, a18, and a19 in Table 3 are the same as the items a1 to a16, a18, and a19 in Table 1, and thus description thereof is omitted.

[Table 3]

  As is apparent from Table 3, in the cooling system L (example) in which the wind from the cooling fan 22 is blown more to the other end side 20b than to the one end side 20a of the radiator 20, its thermal resistance value is 0.97 [° C. / W] is smaller than the thermal resistance value 1.01 [° C./W] of the third cooling system (comparative example), and the wind from the cooling fan 22 blows more to the one end side 20a than the other end side 20b of the radiator 20. Cooling performance can be improved compared with the case where it is done.

  The difference in the cooling performance due to the difference in direction of the cooling fan 22 is that the one end side 20a provided with the inlet line 23 and the outlet line 24 has a narrower air passage than the other end side 20b due to the structure of the radiator 20. And it is thought that the wind sent out from the cooling fan 22 is not formed at right angles to the air blowing port 22a, but has a large angle in the rotation direction as described in FIGS. That is, in the third cooling system (comparative example), in FIG. 9, the wind from the cooling fan 20 is blown from the left side of the radiator 20 toward the right side of the other end side 20b from the left side of the one end side 20a. The wind generated by 20 is blocked by the flow path block 40, and the pressure loss of the wind increases. For this reason, the amount of cold air actually hitting the radiator 20 is reduced, and the cooling effect is reduced. On the other hand, in the present cooling system L (example), the air from the cooling fan 22 is blown from the left side of the other end side 20b of the radiator 20 toward the right side of the one end side 20a in FIG. In 20b, since the part which interrupts | blocks a wind is small compared with the one end side 20a, compared with a 3rd cooling system (comparative example), a wind passage becomes better and the pressure loss of a wind reduces. As a result, the amount of cold air actually hitting the radiator 20 is larger than that of the third cooling system. Thereby, in this cooling system L, it is thought that the cooling effect superior to the 3rd cooling system is acquired. Moreover, since the cooling effect largely depends on the difference between the temperature of the cold air and the temperature of the object, the following reasons can be considered. In the present cooling system L, the cold air having the lowest temperature and the temperature close to room temperature hits the portion (exit line 24) where the temperature of the coolant is the lowest and the temperature difference from the cold air is large. As the liquid temperature at the outlet is further lowered, the cooling effect is enhanced. On the other hand, in the third cooling system, since the wind once warmed at the one end side 20a of the radiator 20 hits the coolest part (exit line 24) near the outlet of the radiator 20, the outlet temperature of the cooling liquid It is estimated that the temperature of the coolant does not decrease in the vicinity.

It is a perspective view which shows the basic concept of the radiator of this invention. It is a disassembled perspective view which shows one Embodiment of the radiator of this invention. It is the same top view. It is sectional drawing which follows the IV-IV line of FIG. It is sectional drawing which follows the VV line of FIG. FIG. 4 is an enlarged sectional view of a part of FIG. 3. It is a top view of the flow-path board single-piece | unit used for the radiator of FIG. 2 thru | or FIG. It is sectional drawing of the same flow-path board single-piece | unit. It is a block diagram of the cooling system containing the radiator of this invention. FIG. 10 is an external view of the cooling fan of FIG. 9. It is a graph which shows air volume distribution of the cooling fan. It is a block diagram of the conventional air cooling system.

Explanation of symbols

20 Radiator 22 Cooling fan 21 Coolant flow path 23 Inlet line 24 Outlet line 30 Channel unit 31 Inlet hole 32 Outlet hole 34U 34L Channel plate 35 Joint surface 36 U-shaped channel recess 37 38 Spacer part 39 Spacer protrusion 40 Flow Road block 41 Upper body 42 Lower body S Cooling air passage space

Claims (8)

An inlet line and an outlet line for the liquid to be cooled; and a plurality of liquid flow paths connected in parallel and spaced from each other between the inlet line and the outlet line and returning from the inlet line to the outlet line Flow path unit;
A radiator characterized by comprising: In the radiator according to claim 1, each flow path unit is formed by laminating and connecting a pair of flow path plates that form a liquid flow path bent at least once in a U shape. A radiator in which an inlet hole and an outlet hole which are connected to the inlet line and the outlet line and constitute a part of the inlet line and the outlet line are formed. 3. The radiator according to claim 2, wherein the pair of flow path plates constituting each flow path unit has a plane symmetrical shape that is symmetric with respect to the overlapping surface, a flow path recess having a planar U shape, and the flow path The radiator which has the said entrance hole and exit hole formed in the one end part and other end part of a recessed part. 4. The radiator according to claim 2, wherein the pair of flow path plates constituting each flow path unit includes a spacer portion protruding outward at the inlet hole and the outlet hole portions, and the stacked flow path units are stacked. A radiator in which the spacer portions abut against each other to form an air passage space in the remaining portion of the flow path unit. The radiator according to any one of claims 2 to 4, wherein an inlet hole and an outlet hole of the plurality of stacked flow path units communicate with each other, and an inlet line and an outlet line are respectively connected to the inlet hole and the outlet hole. The connected radiator. The radiator according to any one of claims 2 to 5, wherein the pair of flow path plates constituting each flow path unit are in contact with each other when being overlapped to ensure a space between the flow path units. Radiator with protrusions formed integrally. The radiator according to any one of claims 1 to 6, a fan that blows air toward a flow path unit of the radiator, a coolant jacket that abuts against a heat source and takes heat of the heat source, and the coolant jacket And a cooling system comprising a liquid pump for circulating a cooling liquid between the radiator and the radiator,
The cooling system, wherein the radiator is arranged so that the inlet line is farther from the outlet line with respect to the fan. The radiator according to any one of claims 1 to 6, a fan that blows air toward a flow path unit of the radiator, a coolant jacket that abuts against a heat source and takes heat of the heat source, and the coolant jacket And a cooling system comprising a liquid pump for circulating a cooling liquid between the radiator and the radiator,
The fan is a centrifugal fan that blows in a centrifugal direction, and when blown toward the flow path unit, the outlet from the inlet line from one end side where the inlet line and the outlet line of the flow path unit are provided. A cooling system characterized by being arranged so that the air volume is increased on the other end side which is folded back into the line.