Cooling system using underground cooling energy

Abstract

Cooling system using underground cooling energy, characterized in that it comprises the following: a cabinet, wherein the cabinet is provided with a housing, wherein the housing is provided with a module to be cooled and a coolant for immersion cooling of the module to be cooled; an underground cave facility used to provide natural underground cooling energy; A circulating cooling system comprising a first heat exchanger, a carbon dioxide storage tank, a circulation pump, and a second heat exchanger, wherein the first heat exchanger is located within the underground cave facility and is used to absorb the natural cooling energy within the underground cave facility, while the second heat exchanger is located within the enclosure and is used to absorb the thermal energy of the cooling fluid, wherein the carbon dioxide storage tank is used to store liquid carbon dioxide, wherein an outlet end of the carbon dioxide storage tank is connected via a first pipe to a first end of the second heat exchanger, and wherein a second end of the second heat exchanger is connected via a second pipe to a first end of the first heat exchanger.wherein a second end of the first heat exchanger is connected via a third pipe to a return line of the carbon dioxide storage tank and forms a circulation line, wherein at least one of the first pipe, the second pipe and the third pipe is equipped with a circulation pump to drive the flow of liquid carbon dioxide within the circulation line.

Description

Technical field

[0001] The present utility model relates to a cooling device, in particular a cooling system using underground cooling energy. State of the art

[0002] With the rapid development of modern technology, the need for efficient and reliable cooling systems in data centers, high-performance computers, and electric vehicles is increasing. Particularly when using high-power-density devices such as GPUs, CPUs, and high-capacity battery modules, the enormous heat generated poses a serious challenge to stable operation and device lifespan. Conventional air- and water-cooled technologies often struggle with efficiency bottlenecks, high energy consumption, high noise levels, and large footprints when faced with the increasing demands for heat dissipation.

[0003] Existing cooling solutions often rely on external cooling towers, chillers, or air conditioning systems, the operation of which not only consumes enormous amounts of energy, but in some regions, high ambient temperatures further increase the cooling load. Furthermore, these external cooling units are also affected by environmental factors such as outside temperature and humidity, which can lead to fluctuations in cooling efficiency.

[0004] In recent years, cooling technologies that utilize natural cooling sources have become a research focus, with the aim of reducing energy consumption and operating costs. Content of the present utility model

[0005] The technical problem to be solved by the present utility model is to provide a cooling system that overcomes the limitations of conventional cooling and can utilize the underground cooling source of the ground for efficient heat dissipation.

[0006] The present utility model describes a cooling system using underground cooling energy, comprising the following: a cabinet 1, wherein the cabinet 1 is provided with a housing 11, wherein the housing 11 is provided with a module to be cooled and a coolant for immersion cooling of the module to be cooled; an underground cave facility 5, which is used to provide natural underground cooling energy; a circulating cooling system comprising a first heat exchanger 3, a carbon dioxide storage tank 2, a circulation pump 25 and a second heat exchanger 12, wherein the first heat exchanger 3 is provided within the underground cave facility 5 and is used to absorb natural cooling energy within the underground cave facility 5, while the second heat exchanger 12 is provided within the casing 11 and is used to absorb the thermal energy of the cooling fluid, wherein the carbon dioxide storage tank 2 is used to store liquid carbon dioxide, wherein an outlet end of the carbon dioxide storage tank 2 is connected via a first pipe 24 to a first end of the second heat exchanger 12, wherein a second end of the second heat exchanger 12 is connected via a second pipe 32 to a first end of the first heat exchanger 3.wherein a second end of the first heat exchanger is connected via a third pipe 31 to a return line of the carbon dioxide storage tank 2 and forms a circulation line, wherein at least one of the first pipe, the second pipe and the third pipe is equipped with a circulation pump 25 for driving the flow of liquid carbon dioxide within the circulation line.

[0007] Furthermore, the number of housings 11 is a plurality, wherein the first end of the second heat exchanger 12 in each of the housings 11 is connected to the first pipe 24 after complete convergence, while the second end of the second heat exchanger 12 in each of the housings 11 is connected to the second pipe 32 after complete convergence.

[0008] Furthermore, the circulation pump 25 is a frequency-variable circulation pump; a temperature sensor is provided inside the housing.

[0009] Furthermore, an insulating layer is applied to the first pipeline, the second pipeline, and the third pipeline.

[0010] Furthermore, the number of first heat exchangers 3 is a plurality and these are connected in parallel to each other.

[0011] Furthermore, the first pipeline, the second pipeline or the third pipeline is equipped with a reserve circulation pump.

[0012] Furthermore, the first pipeline, the second pipeline or the third pipeline is equipped with an emergency shut-off valve.

[0013] Furthermore, the module to be cooled is an electrical and electronic heating element.

[0014] Furthermore, the electrical and electronic heating element is a battery, a GPU, a CPU, or a rectifier-inverter power module.

[0015] This utility model provides a cooling system utilizing subsurface cooling energy. It harnesses the natural cooling energy of underground caves as a permanent, stable, and free cooling source, completely eliminating the need for conventional air conditioning or compressor-driven cooling systems. This significantly reduces the system's energy consumption during operation and enables truly environmentally friendly cooling. The utility model utilizes liquid carbon dioxide as the circulating working fluid, which possesses excellent ecological and physical properties. Its heat absorption in the secondary heat exchanger provides powerful cooling for the enclosure. This utility model combines the efficient temperature homogeneity of immersion cooling with the strong heat dissipation capability of active liquid circulation.Immersion cooling allows the heat from the heating element to be transferred directly and quickly to the cooling fluid, and then the heat is efficiently transported into the underground cave to be released through the carbon dioxide circulation system, creating an efficient heat conduction path from the electronic heating element to the natural cooling source, and the heat dissipation efficiency is much higher than with conventional air or liquid cooling. Brief description of the drawings Fig. Figure 1 shows a schematic representation of the structure of a cooling system using underground cooling energy of the present utility model; Fig. Figure 2 shows a schematic representation of the piping of the cooling system using underground cooling energy of the present utility model. Detailed descriptions

[0016] The embodiments of the present utility model are described in detail below in connection with the attached drawings.

[0017] As in Fig. As shown in Figures 1 to 2, the present utility model represents a cooling system using underground cooling energy, comprising a cabinet 1, an underground cave facility 5 and a circulating cooling system.

[0018] Cabinet 1 contains a number of enclosures 11, and each enclosure 11 houses a module to be cooled. This module is a functional module and an electrical or electronic heating element, which can be a battery, GPU, CPU, hard drive, or rectifier-inverter power module. Cabinet 1 can be an energy storage cabinet, a data center, or a smart data center. Simultaneously, enclosure 11 is filled with coolant for immersion cooling of the modules to be cooled.

[0019] The underground cave facility 5 is used to provide natural subsurface cooling energy, a renewable natural resource derived primarily from the natural cooling of the ground. This energy is evenly distributed and not easily affected by the external climate, making it a reliable cooling source. Utilizing this subsurface cooling energy for the cooling system not only ensures the full utilization of natural resources, reduces energy consumption and lowers costs, but also decreases reliance on conventional cooling methods and reduces carbon dioxide emissions.

[0020] The circulating cooling system is used to transfer the underground cooling energy into the housing 11 in order to cool the coolant inside the housing 11 and finally to cool the module to be cooled, and the circulating cooling system includes a first heat exchanger 3, a carbon dioxide storage tank 2, a circulation pump 25 and a second heat exchanger 12.

[0021] The first heat exchanger 3 is located within the underground cave facility 5 and is used to absorb the natural cooling energy within the underground cave facility 5. The second heat exchanger 12 is located within the housing 11 and is used to absorb the thermal energy of the coolant. The carbon dioxide storage tank 2 is used to store liquid carbon dioxide, with an outlet end of the carbon dioxide storage tank 2 being connected via a first pipe 24 to a first end of the second heat exchanger 12, with a second end of the second heat exchanger 12 being connected via a second pipe 32 to a first end of the first heat exchanger 3, and with a second end of the first heat exchanger 3 being connected via a third pipe 31 to a return of the carbon dioxide storage tank 2, forming a circulation line.At least one of the first pipeline, the second pipeline and the third pipeline is equipped with a circulation pump 25, wherein the circulation pump 25 is used to drive the flow of liquid carbon dioxide within the circulation line in order to ensure heat transfer within the circulation line.

[0022] This utility model provides a cooling system utilizing subsurface cooling energy. It harnesses the natural cooling energy of underground caves as a permanent, stable, and free cooling source, completely eliminating the need for conventional air conditioning or compressor-driven cooling systems. This significantly reduces the system's energy consumption during operation and enables truly environmentally friendly cooling. The utility model utilizes liquid carbon dioxide as the circulating working fluid, which possesses excellent ecological and physical properties. Its heat absorption in the secondary heat exchanger provides powerful cooling for the enclosure. This utility model combines the efficient temperature homogeneity of immersion cooling with the strong heat dissipation capability of active liquid circulation.Immersion cooling allows the heat from the electrical core to be transferred directly and quickly to the cooling fluid, and then the heat is efficiently transported into the underground cavern to be released through the carbon dioxide circulation system, creating an efficient heat conduction path from the electrical core to the natural cooling source, and the heat dissipation efficiency is much higher than with conventional air or liquid cooling.

[0023] An insulating layer is applied to the first, second, and third pipes to insulate them. This minimizes cooling loss through carbon dioxide transport, prevents condensation on the pipe walls, ensures efficient transfer of cooling energy from the underground cavern to the casing, and improves the overall energy efficiency of the system.

[0024] In the present utility model, the number of housings 11 is one or a plurality. If the number is a plurality, the first end of the second heat exchanger 12 in each of the housings 11 is connected to the first pipe 24 after complete convergence, while the second end of the second heat exchanger 12 in each of the housings 11 is connected to the second pipe 32 after complete convergence. The use of converging pipes ensures that all housings are cooled by the same cooling source system, which helps to keep the temperature of each housing constant and avoids differences in the service life of the internal modules caused by uneven cooling.

[0025] In this embodiment, the circulation pump 25 is a variable-frequency circulation pump, and the use of a variable-frequency pump allows the flow rate and velocity of carbon dioxide to be intelligently adjusted according to the actual heat load. Therefore, a temperature sensor is provided in the housing to detect the internal temperature; the pump speed is reduced at low loads to further lower the pump's energy consumption and simultaneously reduce wear and operating noise, thus achieving demand-based cooling and, consequently, precise temperature control, energy savings, and noise reduction.

[0026] In this embodiment, the number of first heat exchangers 3 is multiple and they are connected in parallel. By arranging several first heat exchangers in parallel within the underground cavern, the contact area with the underground cooling source can be increased, thus improving the efficiency of the heat exchange. At the same time, this design also provides a degree of redundancy; even if some of the heat exchangers experience problems, the system can still maintain a portion of its cooling capacity, thereby improving cooling capacity and operational reliability.

[0027] To enhance operational safety, the first, second, or third pipeline is equipped with a backup circulation pump. This pipeline is also equipped with an emergency shut-off valve. If the main circulation pump fails, the backup pump can be activated immediately to ensure uninterrupted cooling. This significantly improves the reliability and availability of system operation, meeting the stringent requirements for continuous operation in industrial and commercial energy storage facilities, data centers, and smart computing environments. In the event of a pipeline leak or other system emergency, the faulty section can be quickly isolated to prevent the release of large quantities of carbon dioxide and ensure the safety of equipment and personnel—a crucial safety feature.

[0028] During operation, the low-temperature liquid carbon dioxide is pressurized by the circulation pump and then transported to the second heat exchanger (serpentine tube) within the housing in a closed piping system. Here, the liquid carbon dioxide and the submerged liquid undergo complete heat exchange, and the temperature rises after absorbing a significant amount of heat. The liquid carbon dioxide is then transported through the insulated piping system to a previously constructed underground cave storage facility. In the underground caves, the liquid carbon dioxide is further cooled and maintained in a stable, liquid state due to the naturally low temperature in the strata and the good thermal insulation.Finally, the cooled liquid carbon dioxide is returned to the aboveground liquid storage tanks via the return pipe system, thus completing the entire recirculating cooling process. The entire system is fully enclosed to ensure no carbon dioxide escapes, and the optimal operating temperature of each section is maintained by a precise temperature control system.

[0029] To increase the system's reliability, several redundancy mechanisms are also provided, including backup pump groups, emergency shutdown valves, and independent power supply units to handle unforeseen situations. These measures not only improve the cabinet's ability to protect itself from extreme conditions but also provide favorable conditions for subsequent troubleshooting and maintenance.

[0030] The cooling system's design takes into account the actual needs of industrial and commercial applications, improving overall system performance through optimized piping and enhanced heat exchange efficiency. In actual operation, the arrangement of the cooling coil pipes is precisely calculated to ensure that the liquid carbon dioxide evenly covers the heat source area of ​​each battery unit, thus achieving efficient heat transfer.

[0031] The present utility model is an innovative cooling system design that abandons the traditional cooling method with integrated liquid cooling in favor of a more efficient, space-optimized solution. This improvement significantly optimizes cabinet space utilization, resulting in a more streamlined and compact overall structure. Simplifying the mechanical structure of the cooling system not only reduces manufacturing costs but also minimizes the complexity of subsequent maintenance. Simultaneously, this new cooling solution ensures thermal performance and eliminates the risk of liquid leakage that can occur with conventional liquid cooling systems, further enhancing the system's safety and reliability.This design optimization not only meets the strict requirements for space utilization in industrial and commercial application scenarios, but also achieves the dual objective of cost control and performance assurance.

[0032] After sufficient heat exchange with the submerged liquid, the low-temperature liquid carbon dioxide absorbs a lot of heat, its temperature rises, and it is transported through the pipeline into the underground cave.

[0033] Due to the naturally low-temperature environment of the layer and its good thermal insulation, the liquid carbon dioxide can be further cooled and kept in a stable liquid state. Special pump units and liquid storage tanks are located outside the enclosure, and the liquid carbon dioxide is transported to the cooling coil network between the individual enclosures by means of a highly efficient circulation pump. This design fully utilizes the excellent thermodynamic properties of carbon dioxide, and its liquid form allows it to efficiently absorb heat from the immersed liquid during the circulation process, resulting in rapid cooling. The heated liquid carbon dioxide is then safely transported to the prepared underground caverns through a specially designed insulated piping system with strictly controlled pressure and flow.Due to the natural low-temperature properties of the deep underground rock layers and the combined effect of the adiabatic barrier formed by the special geological structure and the artificially reinforced thermal insulation layer, the carbon dioxide liquid transported here can continuously and uniformly release heat, gradually lowering the temperature to the ideal state and finally returning it to the liquid storage tank.

[0034] The foregoing is only a preferred embodiment of the present utility model, and it should be noted that for a person skilled in the art a number of improvements and embodiments can be made without derogation from the technical principles of the present utility model, and these improvements and embodiments should also be considered as being within the scope of protection of the present utility model.

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