TWI891268B - Cooling system - Google Patents

Abstract

A cooling system includes a first liquid cooling plate, a second liquid cooling plate, a first thermosiphon device, and a second thermosiphon device. The first liquid cooling plate has a first parallel flow channel formed by two flow channels connected in parallel. The second liquid cooling plate also has a second parallel flow channel formed by two flow channels connected in parallel. The first parallel flow channel and the second parallel flow channel are connected in series. The first thermosiphon device and the second thermosiphon device are both thermally coupled to the first liquid cooling plate and the second liquid cooling plate, and the first thermosiphon device and the second thermosiphon device are located between the first liquid cooling plate and the second liquid cooling plate.

Description

Cooling system

The present invention relates to a cooling system, and more particularly to a cooling system utilizing thermosyphon.

A 1U water-cooled thermosyphon achieves low leakage risk and high heat dissipation capacity by combining the thermosyphon with a cold plate. Furthermore, fins located beneath the cold plate cool the server exhaust, reducing the data center air conditioning load and improving cooling efficiency. However, due to the limited height difference between the evaporator and condenser within the 1U space, a smaller height difference reduces the condensate return capacity. To maximize the height difference, the condenser must be placed at the highest position in the system. This results in contact with the cold plate only from its lower surface, resulting in uneven condenser temperatures. This also reduces the thermosyphon's ability to transfer heat to the cold plate, limiting the cooling capacity of the cooling module.

The present invention aims to provide a cooling system that uses two connected liquid cooling plates to sandwich two thermosyphon devices, thereby enhancing the thermosyphon device's ability to cool a heat source.

According to one embodiment of the present invention, a cooling system includes a first liquid cooling plate, a second liquid cooling plate, a first thermosyphon device, and a second thermosyphon device. The first liquid cooling plate has a first left-side flow channel and a first right-side flow channel, which are connected in parallel to form a first parallel flow channel. The second liquid cooling plate is spaced apart from the first liquid cooling plate and has a second left-side flow channel and a second right-side flow channel, which are connected in parallel to form a second parallel flow channel. The first parallel flow channel and the second parallel flow channel are connected in series. The first thermosyphon device is thermally coupled between the first and second liquid cooling plates, corresponding to the first and second left flow channels. The second thermosyphon device is thermally coupled between the first and second liquid cooling plates, corresponding to the first and second right-side flow channels. This allows both sides of the first and second thermosyphon devices (their condensers) to exchange heat with the first and second liquid cooling plates, compared to prior art configurations where only one side of the condenser exchanges heat with the liquid cooling plate. This improves the cooling capacity of the heat source.

The advantages and spirit of the present invention can be further understood through the following detailed description of the invention and the accompanying drawings.

1: Cooling system

12: First Liquid Cold Plate

12a, 12b: Surface

122: First left channel

122a: Section 1

122b: Second Section

122c: Section 3

122d: Section 4

122e, 122f: Cavity segment

124: First right channel

126: First Entrance

128: First Exit

13: Fins

14: Second liquid cooling plate

14a, 14b: Surface

142: Second left channel

142a: Section 1

142b: Second Section

142c: Section 3

142d: Section 4

142e, 142f: Cavity segment

144: Second right channel

146: Second Entrance

148: Second Exit

16: First thermosyphon device

162: Condenser

164: Evaporator

166: Transmission tube

18: Second thermosyphon device

182: Condenser

184: Evaporator

186: Transmission pipe

20: Connected Structure

22: Flakes

222: Channel

D1: First Direction

D2: Second Direction

D3: Third direction

Figure 1 is a schematic diagram of a cooling system according to one embodiment.

Figure 2 is a partial exploded view of the cooling system in Figure 1.

Figure 3 is a partial exploded view of the cooling system in Figure 1 from another angle.

Figure 4 is a schematic diagram of the internal flow path of the first liquid cooling plate of the cooling system in Figure 1.

Figure 5 is a schematic diagram of the internal flow path of the second liquid cooling plate of the cooling system in Figure 1.

Figure 6 is a schematic diagram of multiple cylindrical fins.

Figure 7 is a schematic diagram of multiple tapered fins.

Figure 8 is a schematic diagram of a plurality of cylindrical fins with slotted grooves.

Figure 9 is a schematic diagram of a fin structure formed by multiple sheet-like objects.

Please refer to Figures 1 to 3. A cooling system 1 according to one embodiment includes a first liquid cooling plate 12, a second liquid cooling plate 14, a first thermosyphon device 16, and a second thermosyphon device 18. The first and second liquid cooling plates 12, 14 are spaced apart from each other in a first direction D1 (indicated by a bidirectional arrow in the figure), and their working fluid flow paths are interconnected. Surface 12a of the first liquid cooling plate 12 and surface 14a of the second liquid cooling plate 14 are opposed to each other. The first thermosyphon device 16 and the second thermosyphon device 18 are sandwiched between (surface 12a of) the first liquid cooling plate 12 and (surface 14a of) the second liquid cooling plate 14. Thus, the first thermosyphon device 16 and the second thermosyphon device 18 can both be directly thermally coupled to (surface 12a of) the first liquid cooling plate 12 and (surface 14a of) the second liquid cooling plate 14. Through heat exchange between the first and second thermosyphon devices 16, 18 and the first and second liquid cooling plates 12, 14, the first and second liquid cooling plates 12, 14 absorb heat energy from the first and second thermosyphon devices 16, 18, thereby achieving a heat dissipation effect. Furthermore, in this embodiment, the first and second liquid cooling plates 12, 14 are connected via a connecting structure 20. The connecting structure 20 is located outside the first and second liquid cooling plates 12, 14. Specifically, in the first direction D1, the projection of the connecting structure 20 does not overlap with the projections of the first and second liquid cooling plates 12, 14.

Please refer to Figure 4, which shows a schematic diagram of the internal flow channel of the first liquid cooling plate 12, which is depicted in cross-section. The first liquid cooling plate 12 has a first left-side flow channel 122 (its scope is indicated by a linked frame in the figure), a first right-side flow channel 124 (its scope is indicated by a linked frame in the figure), a first inlet 126, and a first outlet 128. The first left-side flow channel 122 and the first right-side flow channel 124 are connected in parallel to form a first parallel flow channel. The first inlet 126 and the first outlet 128 are respectively connected to the two ends of this first parallel flow channel; in other words, the first inlet 126 is simultaneously connected to one end of the first left-side flow channel 122 and one end of the first right-side flow channel 124, and the first outlet 128 is simultaneously connected to the other end of the first left-side flow channel 122 and the other end of the first right-side flow channel 124. In actual applications, the working fluid will flow into the first liquid cooling plate 12 through the first inlet 126, then split and flow through the first left channel 122 and the first right channel 124, finally flowing out of the first liquid cooling plate 12 through the first outlet 128. The flow direction of the working fluid in the first liquid cooling plate 12 is indicated by the hollow arrow.

Furthermore, in this embodiment, the first left channel 122 and the first right channel 124 are both U-shaped channels with symmetrical structures. Taking the first left channel 122 as an example, the first left channel 122 comprises, in order of flow direction, a first section 122a, a second section 122b, a third section 122c, and a fourth section 122d (in the figure, their respective areas are indicated by dashed frames). The first section 122a and the fourth section 122d are opposite each other, and the second section 122b and the third section 122c are opposite each other. The flow resistance between the first section 122a and the second section 122b of the first left-side flow channel 122 is smaller than the flow resistance of both the first section 122a and the second section 122b. The flow resistance between the third section 122c and the fourth section 122d of the first left-side flow channel 122 is smaller than the flow resistance of both the third section 122c and the fourth section 122d. This can be achieved by designing the cross-sectional size, shape, and flow channel wall configuration of each section of the first left-side flow channel 122. This flow resistance difference facilitates mixing of the working fluid between sections (e.g., between the first section 122a and the second section 122b, and between the third section 122c and the fourth section 122d), increasing the uniformity of the working fluid temperature and preventing the generation of local hot spots.

In this embodiment, the first left-side flow channel 122 includes three cavity sections 122e and 122f (their respective boundaries are indicated by dashed boxes in the figure). There is one cavity section 122e between the first and second sections 122a and 122b, one cavity section 122e between the third and fourth sections 122c and 122d, and one cavity section 122f between the second and third sections 122b and 122c. Fins are provided in the first, second, third, and fourth sections 122a, 122b, 122c, and 122d, respectively. Fins are not provided in the cavity sections 122e and 122f. This fin configuration ensures that the flow resistance of the first left-side flow channel 122 within the cavity sections 122e and 122f is lower than the flow resistance within the first section 122a, second section 122b, third section 122c, and fourth section 122d. The fins within the first left-side flow channel 122 can increase heat exchange efficiency.

Furthermore, the aforementioned description of the first left-side flow channel 122 also applies to the first right-side flow channel 124 and will not be further elaborated. Furthermore, while the aforementioned description of the first liquid cooling plate 12 uses the structural symmetry between the first left-side flow channel 122 and the first right-side flow channel 124 as an example, this is not a limitation in practice. Furthermore, as shown in Figures 1 to 4 , in this embodiment, a plurality of fins 13 are provided on surface 12b (opposite to surface 12a) of the first liquid cooling plate 12, extending parallel to a second direction D2 (indicated by a bidirectional arrow in the figure). These fins 13 can also exchange heat with the surrounding environment of the first liquid cooling plate 12. For example, when the cooling system 1 is installed in an equipment chassis, the chassis configuration can be designed so that the cooling airflow within the chassis (e.g., generated by a fan) can flow through these fins 13 (e.g., the flow direction of the cooling airflow passing through these fins is substantially parallel to the second direction D2). Thus, the first liquid cold plate 12 can also cool the cooling airflow via these fins 13. This can reduce the cooling burden within the chassis (e.g., by reducing the operating power of the cooling fan) and the cooling burden outside the chassis (e.g., by reducing the operating power of the cooling fan in a cabinet housing multiple devices). This also helps reduce the air conditioning load of the computer room (housing the aforementioned equipment or cabinets).

Please refer to Figure 5, which shows a schematic diagram of the flow channels within the second liquid cooling plate 14, depicted in cross-section. The second liquid cooling plate 14 has a second left-side flow channel 142 (shown as a linked frame in the figure), a second right-side flow channel 144 (shown as a linked frame in the figure), a second inlet 146, and a second outlet 148. The second left-side flow channel 142 and the second right-side flow channel 144 are connected in parallel to form a second parallel flow channel. The second inlet 146 and the second outlet 148 are connected to the two ends of this second parallel flow channel, respectively. In other words, the second inlet 146 is connected to one end of the second left-side flow channel 142 and one end of the second right-side flow channel 144, while the second outlet 148 is connected to the other end of the second left-side flow channel 142 and the other end of the second right-side flow channel 144. In actual applications, the working fluid will flow into the second liquid cooling plate 14 through the second inlet 146 , then split and flow through the second left channel 142 and the second right channel 144 , ultimately exiting the second liquid cooling plate 14 through the second outlet 148 . The flow direction of the working fluid in the second liquid cooling plate 14 is indicated by the hollow arrows.

Furthermore, in this embodiment, the second left channel 142 and the second right channel 144 are both U-shaped channels with symmetrical structures. Taking the second left channel 142 as an example, the second left channel 142 comprises, in order of flow direction, a first section 142a, a second section 142b, a third section 142c, and a fourth section 142d (in the figure, their respective areas are indicated by dashed frames). The first section 142a and the fourth section 142d are opposite each other, and the second section 142b and the third section 142c are opposite each other. The flow resistance between the first and second sections 142a, 142b of the second left-side flow channel 142 is lower than both the flow resistance of the first and second sections 142a, 142b. The flow resistance between the third and fourth sections 142c, 142d of the second left-side flow channel 142 is lower than both the flow resistance of the third and fourth sections 142c, 142d. This difference in flow resistance facilitates mixing of the working fluid between sections (e.g., between the first and second sections 142a, 142b, and between the third and fourth sections 142c, 142d), increasing the uniformity of the working fluid temperature and preventing the generation of local hot spots.

In this embodiment, the second left-side flow channel 142 includes three cavity sections 142e and 142f (their respective boundaries are indicated by dashed boxes in the figure). There is one cavity section 142e between the first and second sections 142a and 142b, one cavity section 142e between the third and fourth sections 142c and 142d, and one cavity section 142f between the second and third sections 142b and 142c. Fins are provided in the first, second, third, and fourth sections 142d, while fins are not provided in the cavity sections 142e and 142f. This fin configuration ensures that the flow resistance of the second left-side flow channel 142 within the cavity sections 142e and 142f is lower than the flow resistance within the first, second, third, and fourth sections 142a, 142b, 142c, and 142d of the second left-side flow channel 142. The fins within the second left-side flow channel 142 enhance heat exchange efficiency.

Furthermore, the aforementioned description of the second left-side flow channel 142 also applies to the second right-side flow channel 144 and will not be further elaborated. Furthermore, while the aforementioned description of the second liquid cooling plate 14 utilizes a symmetrical structure between the second left-side flow channel 142 and the second right-side flow channel 144, this is not a limitation in practice. Furthermore, in practice, a plurality of fins may be provided on the surface 14b (opposite to the surface 14a) of the second liquid cooling plate 14 to facilitate heat exchange with the surrounding environment, thereby achieving substantially the same effect as the aforementioned fins 13.

In addition, please refer to Figures 1, 4, and 5. The first outlet 128 of the first liquid cooling plate 12 and the second inlet 146 of the second liquid cooling plate 14 are connected via a connecting structure 20, thereby connecting the first parallel flow channel of the first liquid cooling plate 12 and the second parallel flow channel of the second liquid cooling plate 14 in series (via the connecting structure 20). Consequently, the working fluid flows through the first liquid cooling plate 12 before flowing through the second liquid cooling plate 14. In this embodiment, the first direction D1 is parallel to the direction of gravity, and the second liquid cooling plate 14 is located above the first liquid cooling plate 12. Therefore, the temperature of the working fluid in the second liquid cooling plate 14 is generally higher than that in the first liquid cooling plate 12. This helps to avoid or reduce the interference of the working fluid temperature gradient on the working fluid flow.

Alternatively, in practice, the connecting structure 20 can be a flexible pipe. Logically, the connecting structure 20 can also be composed of two channel structures disposed on the first and second liquid cooling plates 12, 14. Each channel structure extends from the first outlet 128 of the corresponding first liquid cooling plate 12 or the second inlet 146 of the second liquid cooling plate 14. These two channel structures then connect to form the connecting structure 20. In practice, each channel structure can be integrally formed with the corresponding first or second liquid cooling plate 12, 14. Furthermore, in practice, the first inlet 126 and the second outlet 148 are connected to external piping (e.g., a manifold on a server cabinet (not shown). For example, the working fluid flowing through the first and second liquid cooling plates 12, 14 flows through these piping to an external heat exchanger to dissipate heat energy.

Furthermore, as shown in Figures 1 to 5 , in this embodiment, the first thermosyphon device 16 is thermally coupled between the first and second liquid cooling plates 12, 14, corresponding to the first left-side flow channel 122 and the second left-side flow channel 142 (for example, the first thermosyphon device 16 directly contacts the surface 12a of the first and second liquid cooling plates 12, 14, respectively, and the contact surfaces may be coated with thermally conductive adhesive). The second thermosyphon device 18 is thermally coupled between the first and second liquid cooling plates 12, 14, corresponding to the first and second right-side flow channels 124, 144 (for example, the second thermosyphon device 18 directly contacts the surface 12a of the first and second liquid cooling plates 12, 14, respectively, and the contact surfaces may be coated with thermally conductive adhesive). The first thermosyphon device 16 includes a condenser 162, an evaporator 164, two transmission pipes 166 connecting the condenser 162 and the evaporator 164, and a working fluid flowing within the aforementioned components. The second thermosyphon device 18 includes a condenser 182, an evaporator 184, two transmission pipes 186 connecting the condenser 182 and the evaporator 184, and a working fluid flowing within the aforementioned components. The first thermosyphon device 16 is thermally coupled to the first and second liquid cooling plates 12 and 14 via the condenser 162, and is thermally coupled to a heat source (e.g., a processor) via the evaporator 164. Thus, the first thermosyphon device 16 can transfer heat generated by the heat source to the first and second liquid cooling plates 12 and 14, where the heat energy can be dissipated through an external heat exchanger. The second thermosyphon device 18 is thermally coupled to the first and second liquid cooling plates 12, 14 via a condenser 182. The second thermosyphon device 18 is thermally coupled to a heat source (e.g., a processor) via an evaporator 184. Thus, the second thermosyphon device 18 can transfer heat generated by the heat source to the first and second liquid cooling plates 12, 14, where it can then be dissipated through an external heat exchanger.

Furthermore, through the first parallel flow channel of the first liquid cooling plate 12 and the second parallel flow channel of the second liquid cooling plate 14, as well as the series connection of the first and second parallel flow channels, the first and second liquid cooling plates 12, 14 provide similar cooling conditions for the two heat sources (e.g., processors) thermally coupled to the first and second thermosyphon devices 16, 18, respectively, effectively reducing the temperature difference between the two heat sources.

Furthermore, the series arrangement of the first parallel flow channels of the first liquid cooling plate 12 and the second parallel flow channels of the second liquid cooling plate 14 relatively reduces the number of connections between the liquid cooling plates and external piping (such as the manifold on the server cabinet (not shown). This further reduces the obstruction of the external piping to the cooling airflow within the equipment chassis, thereby reducing fan power consumption.

Furthermore, as shown in Figures 4 and 5 , the fins within the first and second liquid cooling plates 12, 14 are, in principle, thin plates extending parallel to the flow direction of the working fluid. In practice, the fins within the first and second liquid cooling plates 12, 14 may also be implemented using other types of fins, such as cylindrical fins (as shown in Figure 6), pyramidal fins (as shown in Figure 7), or cylindrical fins with a slotted groove (as shown in Figure 8). Furthermore, in practice, the aforementioned fin structure (i.e., a structural configuration formed by multiple fins) may be replaced with other structures that also increase the contact area with the working fluid. For example, as shown in Figure 9, a plurality of flaps 22 are used to form a structure that increases the contact area with the working fluid (logically, it can also be considered a fin structure), replacing the fins previously provided in the first and second liquid cooling plates 12, 14. The flaps 22 are bent to form a plurality of channels 222. The channels 222 extend parallel to a third direction D3 (indicated by a bidirectional arrow in the figure); for example, the third direction D3 is parallel to the flow direction of the first left-side flow channel 122. The plurality of flaps 22 are arranged in the third direction D3. The channels 222 of adjacent flaps 22 are staggered.

In addition, the cooling system 1 can be used in servers for artificial intelligence (AI) computing, edge computing, and can also be used as a 5G server, cloud server, or connected vehicle server.

The above description is merely a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the patent application of the present invention should fall within the scope of the present invention.

1: Cooling system

12: First Liquid Cold Plate

12a: Surface

13: Fins

14: Second liquid cooling plate

14b: Surface

148: Second Exit

16: First thermosyphon device

162: Condenser

164: Evaporator

166: Transmission tube

18: Second thermosyphon device

182: Condenser

184: Evaporator

186: Transmission pipe

20: Connected Structure

D1: First Direction

D2: Second Direction

Claims (9)

A cooling system comprises: a first liquid cooling plate, the first liquid cooling plate having a first left-side flow channel and a first right-side flow channel, the first left-side flow channel and the first right-side flow channel being connected in parallel to form a first parallel flow channel, the first left-side flow channel and the first right-side flow channel both being U-shaped flow channels; a second liquid cooling plate, the second liquid cooling plate spaced apart from the first liquid cooling plate, the second liquid cooling plate having a second left-side flow channel and a second right-side flow channel, the second left-side flow channel and the second right-side flow channel being connected in parallel to form a second parallel flow channel, the first parallel flow channel and the second parallel flow channel being connected in series; a first thermosyphon device, the first thermosyphon device being thermally coupled between the first liquid cooling plate and the second liquid cooling plate corresponding to the first left-side flow channel and the second left-side flow channel; and A second thermosyphon device, thermally coupled between the first liquid cooling plate and the second liquid cooling plate, corresponding to the first right-side flow channel and the second right-side flow channel. The cooling system as described in claim 1 further includes a connecting structure located outside the first liquid cooling plate and the second liquid cooling plate, wherein the first liquid cooling plate has a first inlet and a first outlet, respectively connected to the two ends of the first parallel flow channel, and the second liquid cooling plate has a second inlet and a second outlet, respectively connected to the two ends of the second parallel flow channel, and the first outlet and the second inlet are connected via the connecting structure. The cooling system of claim 2, wherein the second liquid cooling plate is located above the first liquid cooling plate in a gravity direction. The cooling system as described in claim 1, wherein the first left-side flow channel includes two sections in sequence, and the flow resistance of the first left-side flow channel between the two sections is smaller than the flow resistance of any of the two sections. The cooling system as described in claim 4, wherein the first left-side flow channel includes a cavity section located between the two sections, both of which are provided with fins, and the cavity section is not provided with fins. The cooling system of claim 1, wherein the first left-side flow channel and the first right-side flow channel are structurally symmetrical. The cooling system as described in claim 1, wherein a plurality of fins are provided in the first left-side flow channel or the first right-side flow channel, and the fins are thin plates, columns, cones, or columns with a straight groove. A cooling system as described in claim 1, wherein two sheets are arranged in the first left-side flow channel, the sheets are bent to form a plurality of channels, the channels extend parallel to the flow direction of the first left-side flow channel, the two sheets are arranged adjacent to each other in the flow direction, and the channels of the two sheets are staggered. The cooling system as described in claim 1, wherein the first thermosyphon device includes a condenser, an evaporator, and two transmission pipes connecting the condenser and the evaporator, and the first thermosyphon device is thermally coupled to the first liquid cooling plate and the second liquid cooling plate through the condenser.