Multi-stage cooling system

Abstract

This application relates to the field of energy-saving refrigeration technology and provides a multi-stage cooling system, including a primary cooling device, a data center, and a secondary cooling device. The primary cooling device includes a first heat exchanger, which comprises an adjacent first main channel and a first secondary channel. The first main channel contains a desiccant solution used to dry a first airflow within it. The first secondary channel contains a first liquid and a first diverter; the first liquid evaporates into a first vapor and absorbs heat from the first main channel, while the first diverter discharges the first vapor to the external space. The secondary cooling device is connected to the internal space of the data center and is configured to reduce the air temperature within the internal space through the flow of a second diverter. This system enables energy-saving cooling of data centers in hot and humid regions, and also provides highly efficient and energy-saving indirect evaporative cooling in hot and humid regions where evaporative cooling is not feasible.

Description

Technical Field

[0001] This application belongs to the field of energy-saving refrigeration technology, and in particular relates to multi-stage cooling systems. Background Technology

[0002] Data centers (DCs) often need to run a large number of computing tasks, but their internal equipment (such as servers, storage devices, or network switches) generates a lot of heat when running these tasks. Therefore, data centers often require cooling systems to cool their internal spaces.

[0003] Currently, data center cooling often employs either air conditioning or indirect evaporative cooling (IEC) systems. The former requires a large amount of electricity to operate normally, while the latter, although energy-saving, often requires dry and cold ambient air to maintain the system's cooling performance. This results in the need for energy-intensive air conditioning systems to meet the cooling requirements of data centers in hot and humid environments.

[0004] Therefore, achieving cooling operations for data centers in hot and humid regions while saving energy has become an urgent technical problem to be solved. Summary of the Invention

[0005] This application provides a multi-stage cooling system that can solve the problem of how to achieve cooling operation of data centers in hot and humid areas while saving energy.

[0006] In a first aspect, embodiments of this application provide a multi-stage cooling system, which includes a primary cooling device, a data center, and a secondary cooling device; The primary cooling device includes a first heat exchanger, which includes an adjacent first main channel and a first channel. The first main channel is connected to the first channel and the secondary cooling device, respectively. The first main channel includes a desiccant solution, which is used to dry the first airflow in the first main channel. The first airflow is the air in the external space of the data center. After passing through the first main channel, the first airflow flows to the first channel and the second cooling device. The first channel includes a first liquid and a first diversion. The first liquid is used to evaporate into a first gas and absorb heat from the first main channel. The first diversion is used to discharge the first gas to the external space. The first diversion is a portion of the first gas flow that flows into the first channel. The secondary cooling device is connected to the internal space of the data center and is configured to reduce the temperature of the air in the internal space by means of a second diversion of the airflow within the secondary cooling device. The second diversion is a portion of the airflow from the first airflow to the secondary cooling device.

[0007] In some embodiments, the multi-stage cooling system further includes a first ventilation duct, a second ventilation duct, and an auxiliary cooling device; the secondary cooling device includes a second heat exchanger, which includes an adjacent second main channel and a second secondary channel. The second main channel is configured to draw a second airflow from the internal space of the data center and input the second airflow flowing through the second main channel into the internal space; The second channel is connected to the first main channel and includes a second liquid and a second branch. The second liquid is used to evaporate into a second gas and absorb heat from the second main channel. The second branch is used to discharge the second gas to the external space. The first ventilation duct is used to connect the air inlet of the second main channel to the internal space; The second ventilation duct is used to connect the air outlet of the second main channel to the internal space; An auxiliary cooling device is located between the air outlet of the second main channel and the air inlet of the second ventilation duct. It is used to cool the second airflow flowing out of the second main channel when the auxiliary cooling device is turned on.

[0008] In some embodiments, the multi-stage cooling system further includes a processor for acquiring climate information of the environment in which the multi-stage cooling system is located; activating the primary cooling device and the secondary cooling device when the climate information indicates a first climate; deactivating the primary cooling device and the auxiliary cooling device when the climate information indicates a second climate; and activating the auxiliary cooling device, the primary cooling device, and the secondary cooling device when the climate information indicates a third climate.

[0009] In some embodiments, the processor is further configured to acquire humidity data of the environment in which the multi-stage cooling system is located; shut down the first-stage cooling device when the humidity data reaches a first humidity threshold; and turn on the first-stage cooling device when the humidity data reaches a second humidity threshold, wherein the first humidity threshold is less than the second humidity threshold.

[0010] In some embodiments, the primary cooling device further includes a first fan and a second fan, and the secondary cooling device further includes a third fan and a fourth fan. The first fan is located at the air outlet of the first main channel, the second fan is located at the air outlet of the first channel, the third fan is located at the air outlet of the second main channel, and the fourth fan is located at the air outlet of the second channel. The first fan is used to drive the first airflow to flow in the first main channel when the first-stage cooling device is turned on. The second fan is used to drive the first diversion flow in the first channel when the first cooling device is turned on. The third fan is used to drive the second airflow within the second main channel; The fourth fan is used to drive the second flow to flow in the second channel when the primary cooling device is turned on; or, when the primary cooling device is turned off, to drive the first airflow to flow in the second channel.

[0011] In some embodiments, a filter screen is provided on the front side of the third fan to filter out impurities in the second airflow.

[0012] In some embodiments, the system further includes a liquid regeneration device, and the primary cooling device includes a first sprayer and a second sprayer, wherein the first sprayer is disposed at the air outlet of the first main channel and the second sprayer is disposed at the air outlet of the first channel. The first sprayer is used to spray a desiccant solution into the first main channel; The second sprayer is used to spray the first liquid into the first channel; The desiccant solution in the first main channel is used to absorb moisture in the first gas flow to form a diluted solution. A liquid regeneration device is used to collect the diluted solution; reduce the water content in the diluted solution to obtain a desiccant solution, and then transfer the desiccant solution to the first sprayer.

[0013] In some embodiments, the secondary cooling device includes a third sprayer disposed at the air outlet of the secondary channel.

[0014] In some embodiments, the liquid regeneration apparatus includes: The new energy solar collector is used to heat the first working fluid to obtain the second working fluid; and then the second working fluid is transferred to the third heat exchanger. The third heat exchanger includes an adjacent first transmission channel and a second transmission channel. The first transmission channel is used to receive the diluted solution transmitted from the fourth heat exchanger and transmit the resulting heated solution to the regenerator. The second transmission channel is connected to the new energy collector and is used to receive the second working fluid and heat the first transmission channel through the second working fluid to heat the diluted solution and obtain the heated solution. The regenerator is connected to the third heat exchanger to receive the heated solution; it regenerates the heated solution into a desiccant solution and transfers the desiccant solution to the fourth heat exchanger. The fourth heat exchanger includes a third transmission channel and a fourth transmission channel. The third transmission channel is used to collect the dilution solution and transmit the dilution solution to the first transmission channel. The fourth transmission channel is used to receive the desiccant solution transmitted by the regenerator and transmit the desiccant solution to the first sprayer.

[0015] In some embodiments, the liquid regeneration apparatus further includes an auxiliary heater connected to a third heat exchanger for heating a second working fluid flowing through the third heat exchanger upon receiving an auxiliary command.

[0016] The beneficial effects of the embodiments in this application compared with the prior art are: The desiccant in the first main channel of the first heat exchanger in the primary cooling device dehumidifies the hot and humid outside air, thereby reducing its moisture content. The dried air reduces the evaporation limit on the first liquid in the first channel of the first heat exchanger, allowing for significant evaporation. This liquid evaporation enables cooling of the outside air without relying on additional energy, saving energy. The dried and cooled outside air is divided into two streams. One stream flows into the first channel, carrying away the vapor and ensuring the continuous operation of the first heat exchanger, thus continuously drying and cooling the outside space. The other stream enters the secondary cooling device, ensuring significant evaporation of the liquid within the secondary cooling device. This liquid evaporation further cools the hot air inside the data center, saving even more energy. Furthermore, the desiccant can be regenerated using renewable energy, and the air energy used for cooling in each stage of the cooling device is also renewable, making the entire system environmentally friendly. Overall, the combination of primary and secondary cooling devices with indirect evaporative cooling function enables efficient and energy-saving cooling of data centers in hot and humid areas where evaporative cooling is not conducive to energy conservation. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a multi-stage cooling system provided in an embodiment of this application; Figure 2 This is a schematic diagram of the structure of a first heat exchanger provided in an embodiment of this application; Figure 3 This is a schematic diagram of another multi-stage cooling system provided in the embodiments of this application; Figure 4 This is a schematic diagram of another multi-stage cooling system provided in the embodiments of this application; Figure 5 This is a schematic diagram of the structure of the second heat exchanger provided in an embodiment of this application; Figure 6 This is a schematic diagram of an application scenario for a multi-stage cooling system provided in an embodiment of this application. Detailed Implementation

[0019] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0020] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0021] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0022] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0023] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0024] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0025] Data centers, as physical facilities providing data security, management, and storage for enterprises, require cooling of their internal equipment (also known as Information Technology (IT) equipment). To ensure the long-term stable operation of IT equipment, it's crucial to prevent pollutants from the outside air from entering the data center's interior space and causing corrosion. This necessitates designing a cooling system that includes internal air circulation for data center cooling operations. Maintaining a positive pressure environment requires only a very small proportion of fresh air, which can be treated by a separate small-scale fresh air handling unit to achieve the air quality required by the data center; this will not be discussed in this application.

[0026] Current cooling systems, for energy conservation reasons, often employ IEC (Enhanced Energy Storage) systems in addition to cooling tower-based cooling water circulation systems. These IEC systems typically include heat exchangers, fans, and auxiliary refrigeration equipment. The heat exchanger contains two adjacent, isolated airflow channels: a main channel and a secondary channel. The main channel's inlet connects to the data center's outlet, and its outlet connects to the data center's inlet. The secondary channel's inlet and outlet both connect to the external space of the data center. Fans are located at the outlets of both the main and secondary channels, while auxiliary refrigeration equipment is located at the main channel's outlet.

[0027] In dry areas, during IEC system operation, water mist is sprayed into the secondary channels. Driven by fans, two airflow channels flow in their respective channels: the main airflow requiring cooling and the secondary airflow assisting in the evaporation process. The main airflow is the hot air exiting from the data center's vents, while the secondary airflow is dry outside air drawn in from the external space. These two airflows remain physically isolated throughout the process. The hot air is cooled through the main airflow channel, while the dry secondary airflow flows through it. When the secondary airflow passes over the moistened secondary channel surface, moisture evaporates into the air. This evaporation absorbs latent heat, thus cooling the main airflow in the adjacent main channel, thereby cooling the data center in dry areas. If the main airflow at the main channel vents does not reach the desired temperature, auxiliary cooling equipment can be activated to further cool the main airflow at the vents. However, when using the above-mentioned IEC system in hot and humid climates, the high humidity of the outside air will limit the evaporation process of moisture in the secondary channel. However, this is the core cooling mechanism of the IEC system. This will cause the main airflow at the air outlet of the main airflow channel to fail to reach the expected level for a long time, resulting in the auxiliary cooling equipment being turned on for a long time and consuming more energy.

[0028] To address the aforementioned issues, the multi-stage cooling system proposed in this application includes two interconnected IEC devices, i.e., cooling devices. The first-stage cooling device dehumidifies and initially cools the hot and humid air, and the dried and cooled air is introduced into the second-stage cooling device. This ensures the cooling performance of the second-stage cooling device by using the dried and cooled air, thereby achieving energy-saving cooling operation for data centers in hot and humid areas.

[0029] The multi-stage cooling system of this application is described below through detailed embodiments.

[0030] Figure 1 This is a schematic diagram of a multi-stage cooling system provided in an embodiment of this application, as shown below. Figure 1 The multi-stage cooling system 100 shown includes a primary cooling device 200, a data center 300, and a secondary cooling device 400.

[0031] The primary cooling device 200 includes a first heat exchanger 210, which includes an adjacent first main channel 211 and a first channel 212. The first main channel is connected to the first channel 212 and the secondary cooling device 400. The first main channel 211 contains a desiccant solution, which is used to dry the first airflow in the first main channel 211. The first airflow is the air in the external space of the data center 300. After passing through the first main channel 211, the first airflow flows to the first channel 212 and the secondary cooling device 400. The first channel 212 includes a first liquid and a first diversion. The first liquid is used to evaporate into a first gas and absorb the heat of the first main channel 211. The first diversion is used to discharge the first gas to the external space. The first diversion is a portion of the first airflow flowing to the first channel.

[0032] Among them, the primary cooling device 200 is also known as the primary indirect cooling evaporation device.

[0033] The first liquid can be water, which has the advantages of high latent heat of vaporization, low freezing point (avoiding freezing at low temperatures) and high chemical stability (not easily corroding heat exchangers and other equipment), and can absorb a large amount of heat during the evaporation process.

[0034] The desiccant solution can be a lithium bromide (LiBr) solution or a lithium chloride (LiCl) solution, which are solutions with advantages such as high hygroscopicity, high chemical stability and low corrosivity. In the embodiments of this application, LiBr solution or LiCl solution is used as an example.

[0035] The desiccant in the first main channel of the first heat exchanger in the primary cooling device dehumidifies the hot and humid outside air, thereby reducing the moisture content of the air. The dried air reduces the evaporation limit on the first liquid in the first channel of the first heat exchanger, allowing for significant evaporation of the first liquid. Furthermore, the dried and cooled outside air is divided into two streams; one stream flows into the first channel, carrying away the vapor and ensuring the continuous circulation and cooling of the outside space by the first heat exchanger. Figure 1 The first main channel 211 and the first passage 212 are shown in perspective dashed lines.

[0036] like Figure 2 As shown, the first main channel 211 and the first channel 212 of the first heat exchanger 210 share a first heat exchange layer 213. A desiccant is provided on the side of the first heat exchange layer 213 that is in contact with the first main channel 211, and a first liquid is provided on the side of the first heat exchange layer 213 that is in contact with the first channel 212.

[0037] In one implementation, the cross-sections of the first main channel 211 and the first channel 212 are rectangular.

[0038] In one implementation, the plane where the air inlet of the first main channel 211 is located is directly perpendicular to the plane where the air inlet of the first channel 212 is located.

[0039] Continue to combine Figure 1 A third ventilation duct 214, including an air passage, is installed at the air outlet of the first main channel 211. The first end of the third ventilation duct 214 is connected to the air outlet of the first main channel 211, the air passage of the third ventilation duct 214 is connected to the air inlet of the first channel 212, and the second end of the third ventilation duct 214 is connected to the air inlet of the second channel 412 in the secondary cooling device 400. The air outlet of the first channel 212 is connected to the external space of the data center 300. This achieves connection between the first main channel and both the first channel and the secondary cooling device. Consequently, the first airflow exiting from the air outlet of the first main channel 211 is divided into two streams, namely a first branch and a second branch. The first branch is guided to the first channel 212, allowing it to carry the water vapor from the evaporation of the first liquid into the external space of the data center 300, thus achieving indirect evaporative cooling based on the first heat exchanger.

[0040] Continue to combine Figure 2The primary cooling device 200 also includes a first sprayer 220 and a second sprayer 230. The first sprayer 220 is located at the air outlet of the first main channel 211, and the second sprayer 230 is located at the air outlet of the first channel 212. The first sprayer 220 is used to spray a desiccant solution into the first main channel 211; the second sprayer 230 is used to spray a first liquid into the first channel 212. By setting the first sprayer and the second sprayer to continuously spray the corresponding liquid into different channels in the first heat exchanger, the required liquid can be provided to the first main channel and the first channel in a timely manner to continuously achieve dehumidification and cooling of the outside air over a long period of time.

[0041] It should be noted that the air inlets of the first main channel 211 and the first channel 212 can be located on the side of the first heat exchanger 210 closer to the ground, while the air outlets of the first main channel 211 and the first channel 212 can be located on the side of the first heat exchanger 210 furthest from the ground. This ensures that after the desiccant solution absorbs moisture from the first airflow and is diluted in the first main channel 211, it can flow out from the air inlet of the first main channel 211 by gravity. The first liquid can also flow out from the air inlet of the first channel 212 by gravity, facilitating the collection and utilization of liquid during the cooling process.

[0042] It is understood that the embodiments in this application are only for reference. Figure 2 Taking the positions of the air inlet and outlet shown as an example, in practical applications, the positions of the air inlet and outlet in the primary cooling device can also be set independently. However, when setting them, it is necessary to ensure that the first sprayer and the second sprayer are located on opposite sides of the first heat exchanger, and that the first sprayer and the second sprayer are positioned on the side of the first heat exchanger furthest from the ground. For example, when the air inlet of the first main channel and the air inlet of the first channel 212 are located on the side of the first heat exchanger furthest from the ground, the first sprayer can be placed at the air inlet of the first main channel, and the second sprayer can be placed at the air inlet of the first channel.

[0043] Combination Figures 1 to 2 , Figure 3 This is a schematic diagram of another multi-stage cooling system in an embodiment of this application. The first-stage cooling device 200 includes... Figure 2The first sprayer 220 and the second sprayer 230 shown, along with the multi-stage cooling system 100, also include a liquid regeneration device 500. The desiccant solution in the first main channel 211 absorbs moisture from the first airflow to form a diluted solution. The liquid regeneration device 500 collects the diluted solution, reduces the moisture content in the diluted solution to obtain a desiccant solution, and then transmits the desiccant solution to the first sprayer 220. In this technical solution, the liquid regeneration device in the multi-stage cooling system enables the concentration of the diluted desiccant solution in the first main channel (i.e., reducing the moisture content in the diluted solution), achieving the cyclic regeneration of the diluted desiccant solution, thereby ensuring the sustainable operation of the multi-stage cooling system.

[0044] Combination Figure 4 The schematic diagram shown in this application embodiment illustrates a multi-stage cooling system, including a liquid regeneration device 500, comprising: The new energy solar collector 510 is used to heat the first working fluid to obtain the second working fluid; and to transfer the second working fluid to the third heat exchanger 520. The third heat exchanger 520 includes an adjacent first transmission channel 521 and a second transmission channel 522. The first transmission channel 521 is used to receive the diluted solution transmitted by the fourth heat exchanger 540 and transmit the resulting heated solution to the regenerator 530. The second transmission channel 522 is connected to the new energy collector 510 and is used to receive the second working fluid and heat the first transmission channel 521 through the second working fluid to heat the diluted solution and obtain the heated solution. The regenerator 530 is connected to the third heat exchanger 520 and is used to receive the heated solution; regenerate the heated solution into a desiccant solution and transfer the desiccant solution to the fourth heat exchanger 540; The fourth heat exchanger 540 includes a third transmission channel 541 and a fourth transmission channel 542. The third transmission channel 541 is used to collect the dilution solution and transmit the dilution solution to the first transmission channel 521. The fourth transmission channel 542 is used to receive the desiccant solution transmitted by the regenerator 530 and transmit the desiccant solution to the first sprayer 220.

[0045] Among them, the new energy collector 510 can be a solar collector, an air source collector or a geothermal collector. In this embodiment, a solar collector is used as an example.

[0046] The first working medium can be water or heat transfer oil, etc. This application uses water as an example in its embodiments.

[0047] The third heat exchanger 520 and the fourth heat exchanger 540 can be shell-and-tube heat exchangers, plate heat exchangers or coaxial heat exchangers suitable for liquid heat exchange. In the embodiments of this application, the specific types of the third heat exchanger and the fourth heat exchanger are not limited, and the third heat exchanger and the fourth heat exchanger can be different types of heat exchangers.

[0048] In one implementation, the new energy collector 510 can be connected to a first storage tank containing a first working fluid. The first storage tank is connected to a third heat exchanger 520 via a valve and a second transmission channel 522. The new energy collector 510 is configured to use the collected heat energy to heat the first working fluid in the first storage tank. The first storage tank is configured to, after determining that the first working fluid has been heated, control the valve to open so that the heated first working fluid (i.e., the second working fluid) in the storage tank flows to the third heat exchanger 520 through the second transmission channel 522.

[0049] The regenerator 530 is connected to the first transmission channel 521 and the fourth transmission channel 542. The regenerator 530 is configured to draw in outside air and use the outside air to carry away the water vapor evaporated from the heated solution, thus obtaining a desiccant solution. The desiccant solution can then flow to the fourth heat exchanger 540 through the fourth transmission channel 542. The desiccant solution flowing out of the regenerator 530 has a certain temperature. When it flows through the fourth transmission channel 542, it can transfer its own heat to the third transmission channel 541, thereby preheating the diluted solution. In this way, the third heat exchanger can quickly heat the received diluted solution to the desired temperature, achieving energy savings.

[0050] In one implementation, the liquid regeneration device 500 further includes a second storage tank for collecting the dilution solution. A fourth heat exchanger 540 can draw the dilution solution from the second storage tank to ensure that the water in the dilution solution is removed after passing through the fourth heat exchanger 540, the third heat exchanger 520, the regenerator 530, and the fifth heat exchanger 550, becoming a desiccant solution that can be circulated and sprayed by the first sprayer 220. Figure 4 The arrows in each transmission channel indicate the flow direction of the diluted desiccant solution during the regeneration process.

[0051] In one implementation, continue to combine Figure 4 The liquid regeneration device 500 also includes a fifth heat exchanger 550 disposed between the first sprayer 220 and the fourth heat exchanger 540. The fifth heat exchanger 550 includes a fifth transmission channel and a sixth transmission channel. The fifth transmission channel is connected to the fourth transmission channel 542 to transmit the desiccant solution to the first sprayer 220. The sixth transmission channel is equipped with condensate water to cool the desiccant solution in the fifth transmission channel. In this way, the desiccant solution can undergo two-stage cooling through the fourth and fifth heat exchangers after flowing out of the regenerator, thereby reducing the water vapor partial pressure on the surface of the desiccant solution, ensuring the dehumidification capacity of the desiccant solution, and reducing the moisture content of the first airflow. Figure 4 Only the fifth transmission channel (i.e. the line connecting the fifth heat exchanger 550 to the fourth heat exchanger 540) is shown.

[0052] In one implementation, continue to combine Figure 4 The liquid regeneration device 500 also includes an auxiliary heater 560 disposed between the new energy collector 510 and the third heat exchanger 520. The auxiliary heater 560 is connected to the second transmission channel 522 in the third heat exchanger 520 and is used to heat the second working fluid flowing through the third heat exchanger 520 upon receiving an auxiliary command. In this technical solution, when the external climate of the data center is unfavorable, resulting in insufficient heat collected by the new energy collector to heat the first working fluid to a higher temperature, the auxiliary heater can be activated in time to continue heating the second working fluid, thereby ensuring the regeneration process of the desiccant solution and maintaining the operation of the multi-stage cooling system, thus improving the system stability.

[0053] The secondary cooling device 400 is connected to the internal space of the data center 300 and is configured to reduce the temperature of the air in the internal space by means of a second flow within the secondary cooling device 400. The second flow is a portion of the airflow from the first airflow to the secondary cooling device.

[0054] Among them, the secondary cooling device 400 is also known as the secondary indirect cooling evaporation device.

[0055] In one implementation, combining Figure 4 The multi-stage cooling system 100 also includes a first ventilation duct 600, a second ventilation duct 700 and an auxiliary cooling device 800, and a secondary cooling device 400, including a second heat exchanger 410, which includes an adjacent second main channel 411 and a second secondary channel 412. The second main channel 411 is configured to draw a second airflow from the interior space of the data center 300 and input the second airflow flowing through the second main channel into the interior space; The second channel 412 includes a second liquid and a second diverter. The second liquid is used to evaporate into a second gas and absorb heat from the second main channel 411. The second diverter is used to discharge the second gas to the external space. The first ventilation duct 600 is used to connect the air inlet of the second main channel 411 and the internal space; The second ventilation duct 700 is used to connect the air outlet of the second main channel 411 and the internal space. The auxiliary cooling device 800 is located between the air outlet of the second main channel 411 and the air inlet of the second ventilation duct 700, and is used to cool the second airflow flowing out of the second main channel when the auxiliary cooling device 800 is turned on.

[0056] The second airflow is hot air from inside the data center 300. As it flows through the second main channel 411, it transfers heat to the second channel 412. The second branch flow within the second channel 412 is part of the dried first airflow. In the second channel 412, the evaporation of the second liquid is not restricted, allowing a large amount of the second liquid to evaporate into gas. This gas absorbs the heat transferred by the second airflow in the second main channel 411. As the second branch flow expels the evaporated gas into the external space, the heat in the second airflow is also expelled, achieving cooling of the hot air based on liquid evaporation. This allows for cooling of data centers in hot and humid regions while saving energy.

[0057] like Figure 5 As shown, the second main channel 411 and the second channel 412 of the second heat exchanger 410 share a second heat exchange layer 413, and a second liquid is provided on the side of the second heat exchange layer 413 that is in contact with the second channel 412. The second liquid is similar to the first liquid and will not be described again.

[0058] Continue to combine Figure 4 and Figure 5 The secondary cooling device 400 also includes a third sprayer 420, which is installed at the air outlet of the second channel 412; the third sprayer 420 is used to spray the second liquid into the second channel 412.

[0059] The air inlet of the second main channel 411 and the air outlet of the second channel 412 of the secondary cooling device can be located on the side of the second heat exchanger 410 away from the ground, and the air outlet of the second main channel 411 and the air inlet of the second channel 412 can be located on the side of the second heat exchanger 410 close to the ground.

[0060] By continuously spraying the second liquid into the second channel using a third sprayer, sufficient second liquid can be ensured for evaporation, thus continuously cooling the hot air inside the data center over a long period. Furthermore, placing the third sprayer on the side of the second heat exchanger furthest from the ground allows excess second liquid in the second channel to flow out by gravity, eliminating the need for additional collection devices and reducing the impact of excessive liquid in the second channel on evaporation.

[0061] In one implementation, the cross-sections of the second main channel 411 and the second secondary channel 412 are rectangular.

[0062] In one implementation, the plane where the air inlet of the second main channel 411 is located is directly perpendicular to the plane where the air outlet of the second channel 412 is located.

[0063] In one implementation, the multi-stage cooling system 100 further includes a processor for acquiring climate information of the environment in which the multi-stage cooling system is located; when the climate information indicates a first climate, activating the primary cooling device 200 and the secondary cooling device 400; when the climate information indicates a second climate, deactivating the primary cooling device 200 and the auxiliary cooling device 800; and when the climate information indicates a third climate, activating the auxiliary cooling device 800, the primary cooling device 200, and the secondary cooling device 400.

[0064] Among them, climate information is used to indicate the season of the environment in which the multi-stage cooling system is located. The first climate indicates spring or autumn, the second climate indicates winter, and the third climate indicates summer.

[0065] The processor can obtain climate information from the weather forecasting center in the area where the multi-stage cooling system is located.

[0066] During colder winter months, the temperature outside the data center is low, resulting in both low ambient air temperature and humidity. In this season, the processor can control the primary cooling unit 200 and auxiliary cooling unit 800 in the multi-stage cooling system 100, activating only the secondary cooling unit 400. At this time, the low-temperature, low-humidity ambient air can flow directly through the secondary channel 412 without affecting the evaporation of the secondary liquid. In this scenario, ambient air, i.e., the first airflow, can be directly drawn into the secondary channel 412. The secondary cooling unit 400 as a whole can function as an air-to-air heat exchanger, facilitating heat exchange between the incoming and outgoing airflows.

[0067] In spring or autumn, the air outside data centers located in hot and humid regions remains highly humid. At this time, processors simultaneously activate both primary and secondary cooling systems. In this scenario, the multi-stage cooling system removes excess moisture from the outside air through the primary cooling system, ensuring a dry air supply to the secondary cooling system. This enables the secondary cooling system to perform indirect evaporative heat exchange, ensuring that even in warm and humid environments, indirect evaporation technology can still cool the air inside the data center, saving energy and reducing the operating time of auxiliary cooling devices.

[0068] During hot and humid summers, the processor simultaneously activates the primary cooling system, the secondary cooling system, and the auxiliary cooling system. In this situation, the multi-stage cooling system removes excess moisture from the outside air through the primary cooling system, ensuring a dry air supply to the secondary cooling system. This enables the secondary cooling system to perform indirect evaporative heat exchange. The auxiliary cooling system further cools the second airflow exiting the secondary cooling system, ensuring that the air inside the data center is strictly cooled to the required temperature. This allows the multi-stage cooling system to operate reliably under extreme climatic conditions of high temperature and high humidity.

[0069] In the above technical solution, the processor can dynamically select to turn on or off the primary cooling device and auxiliary cooling device based on different climate information. This allows for selective operation of different devices under different climates, thereby reducing the air temperature inside the data center while effectively utilizing different devices to improve energy efficiency.

[0070] In one implementation, the processor is further configured to acquire the temperature of the environment in which the multi-stage cooling system is located; when the climate information indicates a second climate and the temperature reaches a first temperature threshold, the processor shuts down the first-stage cooling device 200, the auxiliary cooling device 800, and the third sprayer 420; when the climate information indicates a first climate and the temperature reaches a second temperature threshold, the processor turns on the auxiliary cooling device 800, the first-stage cooling device 200, and the second-stage cooling device 400; the second temperature threshold is greater than the first temperature threshold.

[0071] The first and second temperature thresholds can be set according to relevant data center specifications, and no specific restrictions are imposed in this embodiment. When the temperature is low enough in winter, the processor can shut down the third sprayer, allowing the activated secondary cooling device to operate as a dry heat exchanger. This not only saves water resources but also further reduces the energy consumption of the multi-stage cooling system. In spring or autumn, when the temperature is high, the humidity of the outside air also increases. At this time, activating the auxiliary cooling device, the primary cooling device, and the secondary cooling device in the multi-stage cooling system allows for rapid cooling of the hot air in the data center to the required temperature, in addition to dehumidifying and cooling the outside air, ensuring the stable and reliable operation of the data center. This enables the multi-stage cooling system to cope with sudden climate changes and enhances its environmental adaptability.

[0072] In one implementation, the processor is further configured to acquire humidity data of the environment in which the multi-stage cooling system is located; when the humidity data reaches a first humidity threshold, the first-stage cooling device 200 is turned off; when the humidity data reaches a second humidity threshold, the first humidity threshold is less than the second humidity threshold.

[0073] The first and second humidity thresholds can be set according to local environmental conditions, and no specific restrictions are imposed in this embodiment. The processor can also obtain humidity data from a weather forecast center. In the above technical solution, when the humidity data of the environment where the multi-stage cooling system is located is less than or equal to the first humidity threshold, it means that the external humidity is low. At this time, the first-stage cooling device is forcibly shut down, and the second-stage cooling device is used for cooling. When the humidity data of the environment where the multi-stage cooling system is located is greater than or equal to the second humidity threshold, it means that the external humidity is high. At this time, the first-stage cooling device is forcibly turned on to dehumidify the humid air in a timely manner. This realizes the dynamic adjustment of the number of cooling devices in the multi-stage cooling system based on the external humidity data, thereby achieving reliable cooling operation of the data center.

[0074] Continue to combine Figure 4 The primary cooling device 200 also includes a first fan 240 and a second fan 250, and the secondary cooling device 400 also includes a third fan 430 and a fourth fan 440. The first fan 240 is located at the air outlet of the first main channel 211, the second fan 250 is located at the air outlet of the first channel 212, the third fan 430 is located at the air outlet of the second main channel 411, and the fourth fan 440 is located at the air outlet of the second channel 412.

[0075] The first fan 240 is used to drive the first airflow to flow in the first main channel 211 when the first cooling device 200 is turned on.

[0076] The second fan 250 is used to drive the first diverter to flow in the first channel 212 when the first cooling device 200 is turned on.

[0077] The third fan 430 is used to drive the second airflow within the second main channel 411; The fourth fan 440 is used to drive the second flow to flow in the second channel when the first cooling device 200 is turned on; or, when the first cooling device 200 is turned off, to drive the first airflow to flow in the second channel 412.

[0078] It should be noted that the first fan 240, the second fan 250, the third fan 430 and the fourth fan 440 can also be installed at the air inlet of the corresponding channel.

[0079] In the above technical solution, the fans installed at the air outlets of the first and second heat exchangers can powerfully deliver air to the corresponding channels to ensure that different airflows flow in the corresponding channels, thereby realizing the cooling function of the multi-stage cooling system.

[0080] In one implementation, a filter is installed in front of the third fan to remove impurities from the second airflow. The filter further removes impurities from the air entering the data center, thereby reducing the corrosive effects of airborne pollutants on the data center's internal equipment.

[0081] The following is combined Figure 6 The illustrated application scenario explains the specific operation of a multi-stage cooling system specifically designed to address the cooling needs of data centers located in hot and humid climates. In the first stage, outdoor air (an example of the first airflow) is drawn into the main channel (an example of the first main channel) of a Liquid Desiccant Indirect Evaporative Cooling (LD-IEC) unit (an example of a primary cooling device). During this process, the outdoor air is sprayed with a liquid desiccant solution to promote dehumidification (an example of a first sprayer spraying desiccant solution into the first main channel). This process is particularly suitable for handling humid outdoor air because the desiccant absorbs moisture and reduces air humidity. After dehumidification, the air passes through the main channel of the LD-IEC unit and is separated into two distinct airflows. One airflow (an example of a second split) is guided to a secondary channel (an example of the first channel) within the same LD-IEC unit, where it is sprayed with water mist (an example of a second sprayer spraying the first liquid into the first channel). The evaporation of this water provides initial cooling to the air in the main channel. The other cooled airflow (an example of the first split) serves as the secondary air for the subsequent second-stage conventional IEC unit (an example of a secondary cooling device).

[0082] In the second stage, hot air heated by IT equipment within the data center (an example of a second airflow) is introduced into the main channel of the IEC unit (an example of a second main channel). The hot air undergoes indirect evaporative cooling in the main channel of the IEC unit, transferring heat to the secondary channel. This secondary channel is sprayed with water mist (an example of a third sprayer spraying a second liquid into a second channel). The water mist in this channel absorbs heat and evaporates, cooling the air in the main channel. The evaporated water vapor then enters the secondary air in this channel without adding moisture to the air in the main channel. This ensures that the air supplied to the data center remains cool and dry, meeting the stringent cooling requirements of the IT equipment. Under specific circumstances, such as when the air exhausted from the IEC unit does not reach the desired temperature (e.g., extreme weather conditions or prolonged rainy weather hindering the liquid desiccant regeneration process, thus affecting the cooling of the hot air and causing it to fall short of the desired temperature), additional auxiliary cooling equipment (an example of an auxiliary refrigeration unit) will be activated.

[0083] Liquid desiccant regeneration is a crucial part of a multi-stage cooling system because it restores the dehumidifying effect of the solution. The liquid desiccant solution can be circulated from a liquid desiccant storage tank (an example of a second storage tank) to a liquid regenerator (an example of a liquid regeneration device). The liquid regenerator utilizes solar energy, collecting heat through a solar water tank (an example of a first storage tank) connected to a solar collector or a photovoltaic-thermal (PV / T) system (an example of a new energy collector). A heat exchanger (an example of a third heat exchanger) is connected to the solar water tank. It heats the liquid desiccant solution (an example of a diluted solution) after it has absorbed moisture by heating water. The heated solution (i.e., the heated solution) is then transferred to a regenerator to remove the absorbed moisture. The regenerated concentrated liquid desiccant (also known as a "heat-intensity desiccant solution," another example of a desiccant solution) flows through a liquid heat exchanger (an example of a fourth heat exchanger). During this process, some of the heat in the concentrated liquid desiccant is dissipated. The solution then enters a heat exchanger containing condensate (an example of a fifth heat exchanger) and is transferred to a desiccant sprayer (an example of a first sprayer) to complete the liquid regeneration process.

[0084] To address situations with insufficient solar energy, such as prolonged cloudy or rainy days, an auxiliary heating system (an example of an auxiliary heater) is integrated into the liquid regenerator. Located downstream of the solar heating components (i.e., the solar collector and solar water tank), this system provides additional heat to ensure continuous regeneration of the liquid desiccant solution. The auxiliary heating system can be provided via a heat pump module or a local heating network, depending on the environmental conditions and available infrastructure of the DC facility. Figure 6 The primary and secondary channels of LD-IEC and IEC units are not shown.

[0085] In summary, the multi-stage cooling system combines indirect evaporative cooling, liquid desiccant dehumidification, solar-assisted regeneration, and auxiliary heating, enabling robust and energy-efficient management of the heat load in data centers in hot and humid regions. It significantly reduces reliance on traditional mechanical refrigeration compression systems. By minimizing the operation of energy-intensive mechanical refrigeration, the multi-stage cooling system achieves the following advantages: 1) Energy saving: By utilizing indirect evaporative cooling and desiccant solution dehumidification, the power load associated with data center air conditioning systems can be reduced.

[0086] 2) Save energy costs: Reducing energy consumption can significantly reduce operating costs, especially in areas with high energy costs.

[0087] 3) High sustainability: Reducing reliance on mechanical cooling systems and utilizing physical evaporation processes helps reduce greenhouse gas emissions, which is in line with sustainable development goals and environmental standards.

[0088] In this embodiment, hot and humid outside air first flows into the primary cooling device. As it flows through the first main channel, the desiccant within dehumidifies the outside air, reducing its moisture content. The dried air reduces the evaporation limitations on the first liquid in the adjacent first channel, allowing for significant evaporation and achieving initial cooling of the outside air within the first main channel without relying on additional energy. The dried air is then divided into two streams. One stream flows into the first channel, carrying away the vapor and ensuring the first heat exchanger continues its cyclical operation, continuously drying and cooling the outside air. The other stream enters the second channel of the secondary cooling device. Because this air is dry and cooled, it reduces the limitations on the evaporation process of the second liquid, allowing for significant evaporation and carrying away the evaporated water vapor. This cools the hot air inside the data center within the second main channel, ensuring air circulation within the data center and thus cooling the data center. The combined use of the primary and secondary cooling devices achieves the goal of cooling a data center in a hot and humid region while saving energy. To maintain a positive pressure environment, only a very small proportion of fresh air is needed, and this portion of fresh air can be treated by a separate small fresh air handling unit to achieve the air quality required by the data center, which is not discussed in this application.

[0089] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0090] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0091] In the embodiments provided in this application, it should be understood that the disclosed apparatus / network devices and methods can be implemented in other ways. For example, the apparatus / network device embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0092] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0093] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A multi-stage cooling system, characterized in that, The system includes a primary cooling device, a data center, and a secondary cooling device; The primary cooling device includes a first heat exchanger, which includes an adjacent first main channel and a first channel. The first main channel is connected to the first channel and the secondary cooling device. The first heat exchanger includes a common first heat exchange layer located between the first main channel and the first channel. A desiccant is provided on the side of the first heat exchange layer that is in contact with the first main channel. A first liquid is provided on the side of the first heat exchange layer that is in contact with the first channel. A third ventilation duct including an air passage is provided at the air outlet of the first main channel. The first end of the third ventilation duct is connected to the air outlet of the first main channel, and the air passage of the third ventilation duct is connected to the air inlet of the first channel. The first main channel includes a desiccant solution, which is used to dry the first airflow in the first main channel. The first airflow is the air in the external space of the data center. After passing through the first main channel, the first airflow flows to the first channel and the second cooling device. The first channel includes a first liquid and a first diversion. The first liquid is used to evaporate into a first gas and absorb heat from the first main channel. The first diversion is used to discharge the first gas to the external space. The first diversion is a portion of the first gas flow that flows into the first channel. The secondary cooling device is connected to the internal space of the data center and is configured to reduce the temperature of the air in the internal space by means of a second diversion of the airflow within the secondary cooling device. The second diversion is a portion of the airflow from the first airflow to the secondary cooling device.

2. The system as described in claim 1, characterized in that, The multi-stage cooling system also includes a first ventilation duct, a second ventilation duct, and an auxiliary cooling device. The secondary cooling device includes a second heat exchanger, which includes an adjacent second main channel and a second channel. The second main channel is configured to draw a second airflow from the interior space of the data center and input the second airflow flowing through the second main channel into the interior space; The second channel is connected to the first main channel and includes a second liquid and a second diverter. The second liquid is used to evaporate into a second gas and absorb heat from the second main channel. The second diverter is used to discharge the second gas into the external space. The first ventilation duct is used to connect the air inlet of the second main channel and the internal space; The second ventilation duct is used to connect the air outlet of the second main channel and the internal space; The auxiliary cooling device is located between the air outlet of the second main channel and the air inlet of the second ventilation duct, and is used to cool the second airflow flowing out of the second main channel when the auxiliary cooling device is turned on.

3. The system as described in claim 2, characterized in that, The multi-stage cooling system also includes a processor for acquiring climate information of the environment in which the multi-stage cooling system is located; and for activating the first-stage cooling device and the second-stage cooling device when the climate information indicates a first climate. If the climate information indicates a second climate, shut down the primary cooling device and the auxiliary cooling device. When the climate information indicates a third climate, the auxiliary cooling device, the primary cooling device, and the secondary cooling device are activated.

4. The system as described in claim 3, characterized in that, The processor is further configured to acquire humidity data of the environment in which the multi-stage cooling system is located; shut down the first-stage cooling device when the humidity data reaches a first humidity threshold; and turn on the first-stage cooling device when the humidity data reaches a second humidity threshold, wherein the first humidity threshold is less than the second humidity threshold.

5. The system according to any one of claims 2 to 4, characterized in that, The primary cooling device further includes a first fan and a second fan, and the secondary cooling device further includes a third fan and a fourth fan. The first fan is located at the air outlet of the first main channel, the second fan is located at the air outlet of the first channel, the third fan is located at the air outlet of the second main channel, and the fourth fan is located at the air outlet of the second channel. The first fan is used to drive the first airflow to flow in the first main channel when the first-stage cooling device is turned on. The second fan is used to drive the first diverter to flow in the first channel when the first-stage cooling device is turned on; The third fan is used to drive the second airflow to flow within the second main channel; The fourth fan is used to drive the second diverter to flow in the second channel when the first cooling device is turned on; or, when the first cooling device is turned off, to drive the first airflow to flow in the second channel.

6. The system as described in claim 5, characterized in that, A filter screen is provided on the front side of the third fan to filter out impurities in the second airflow.

7. The system according to any one of claims 2 to 4, characterized in that, The system also includes a liquid regeneration device, and the primary cooling device includes a first sprayer and a second sprayer. The first sprayer is located at the air outlet of the first main channel, and the second sprayer is located at the air outlet of the first channel. The first sprayer is used to spray the desiccant solution into the first main channel; The second sprayer is used to spray the first liquid into the first channel; The desiccant solution in the first main channel is used to absorb moisture in the first airflow to form a diluted solution; The liquid regeneration device is used to collect the diluted solution; The moisture content in the diluted solution is reduced to obtain the desiccant solution, and the desiccant solution is then transferred to the first sprayer.

8. The system as described in claim 6, characterized in that, The secondary cooling device includes a third sprayer, which is located at the air outlet of the second channel.

9. The system as described in claim 7, characterized in that, The liquid regeneration device includes: The new energy solar collector is used to heat a first working fluid to obtain a second working fluid; and then transfers the second working fluid to a third heat exchanger. The third heat exchanger includes an adjacent first transmission channel and a second transmission channel. The first transmission channel is used to receive the diluted solution transmitted from the fourth heat exchanger and transmit the resulting heated solution to the regenerator. The second transmission channel is connected to the new energy collector and is used to receive the second working fluid and heat the first transmission channel through the second working fluid to heat the diluted solution and obtain the heated solution. The regenerator is connected to the third heat exchanger and is used to receive the heated solution; regenerate the heated solution into the desiccant solution, and transfer the desiccant solution to the fourth heat exchanger; The fourth heat exchanger includes a third transmission channel and a fourth transmission channel. The third transmission channel is used to collect the dilution solution and transmit the dilution solution to the first transmission channel. The fourth transmission channel is used to receive the desiccant solution transmitted by the regenerator and transmit the desiccant solution to the first sprayer.

10. The system as described in claim 9, characterized in that, The liquid regeneration device further includes an auxiliary heater connected to the third heat exchanger, used to heat the second working fluid flowing through the third heat exchanger upon receiving an auxiliary command.

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