Indirect evaporative cooling system based on solar heat collection and liquid desiccant

Abstract

The invention discloses an indirect evaporative cooling system based on solar heat collection and a liquid drying agent, belongs to the technical field of data centers, and aims to solve the technical problem of loss of an energy conversion chain caused by balance between independent temperature and humidity control requirements and regeneration energy consumption and insufficient gradient utilization of full spectrum of solar energy. Comprising a first-stage indirect evaporative cooler for dehumidifying and preliminarily cooling outdoor air, and a second-stage indirect evaporative cooler for cooling dry air output by the first-stage indirect evaporative cooler; the auxiliary cooling device is communicated with an air outlet channel of the secondary indirect evaporative cooler and provides auxiliary heat exchange for hot return air generated by the data center; the liquid desiccant regeneration device comprises a solar collector, a heat exchanger between a solar system and a heat storage system, a heat storage tank, a heat exchanger between the heat storage system and a desiccant system, a desiccant regenerator, a regenerator and an auxiliary heater.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of data centers, in particular to an indirect evaporative cooling system based on solar heat collection and liquid desiccant. BACKGROUND

[0002] The energy consumption of data center cooling systems accounts for about 30-40% of the total energy consumption, becoming a key factor restricting the sustainable development of the industry. Among the current mainstream cooling technologies, mechanical compression refrigeration relies on electrically driven compressors for refrigerant phase change cycles, with a coefficient of performance (COP) of 3.0-5.0, but the operating cost is high during peak electricity price periods and the carbon emission intensity is high, making it difficult to meet the development requirements of green data centers. Evaporative cooling technology achieves energy saving and cooling by water evaporation heat absorption, but direct evaporative cooling significantly increases air humidity, which has limited applicability in humidity-sensitive data center environments. Indirect evaporative cooling avoids humidification by isolating air flow through a heat exchanger, but its cooling efficiency is limited by outdoor wet-bulb temperature, and its performance significantly decreases in high-temperature and high-humidity areas, with a COP of less than 2.0, often requiring backup mechanical refrigeration systems, resulting in redundant investment.

[0003] To reduce the energy consumption of traditional cooling technologies, some solutions attempt to integrate solar technology. Solar photovoltaic-driven compressors have low photoelectric conversion efficiency (usually less than 22%) and intermittent problems. Solar heat-driven absorption refrigeration requires a high-temperature heat source of 80℃ or higher, and the system is complex and difficult to match the normal output grade of low-temperature solar energy (40-65℃). It is worth noting that liquid desiccant dehumidification technology can expand the humidity range of evaporative cooling, but the regeneration of desiccant requires continuous consumption of 60-80℃ low-temperature heat energy, and existing electric heating or steam regeneration methods essentially offset the energy saving benefits.

[0004] The balance between the demand for independent temperature and humidity control and the regeneration energy consumption, as well as the insufficient step-by-step utilization of solar full spectrum, leads to losses in the energy conversion chain, which is a technical problem that needs to be solved. SUMMARY

[0005] The technical task of the present application is to solve the above problems, and provide an indirect evaporative cooling system based on solar heat collection and liquid desiccant, to solve the technical problem of the balance between the demand for independent temperature and humidity control and the regeneration energy consumption, as well as the insufficient step-by-step utilization of solar full spectrum, leading to losses in the energy conversion chain.

[0006] The present application provides an indirect evaporative cooling system based on solar heat collection and liquid desiccant, which comprises a desiccant-based primary indirect evaporative cooler, a desiccant-based secondary indirect evaporative cooler, an auxiliary cooling device, and a liquid desiccant regeneration device driven by solar energy.

[0007] The primary indirect evaporative cooler is provided with a cooling water heat exchanger and a primary cooling water spraying unit on the air inlet channel, the air inlet pipeline of the cooling water heat exchanger is connected with a liquid desiccant spraying unit for dehumidifying outdoor primary air, and the primary cooling water spraying unit is used for preliminary cooling of the outdoor primary air, and the liquid outlet channel of the primary indirect evaporative cooler is provided with a liquid desiccant storage pool.

[0008] The air inlet channel of the secondary indirect evaporative cooler is communicated with the air outlet channel of the primary indirect evaporative cooler, the air inlet channel of the secondary indirect evaporative cooler is provided with a secondary cooling water spraying unit for cooling dry air output by the primary indirect evaporative cooler, low-temperature air is output, and the low-temperature air exchanges heat with hot return air generated by the data center through the auxiliary evaporative coil arranged in the data center, and the liquid outlet channel of the secondary indirect evaporative cooler is provided with a waste water recovery device.

[0009] The auxiliary cooling device includes a compressor, a condenser and an expansion valve connected between the compressor and the condenser, the compressor and the condenser are connected with the auxiliary evaporative coil, and when the temperature of the low-temperature air output by the secondary indirect evaporative cooler is higher than a threshold value, the auxiliary cooling device is used for providing auxiliary heat exchange for the hot return air generated by the data center.

[0010] The liquid desiccant regeneration device includes a solar collector, a heat exchanger between the solar system and the heat storage system, a heat storage tank, a heat exchanger between the heat storage system and the desiccant system, a desiccant regenerator, a heat recovery device and an auxiliary heater, the solar collector is used for collecting solar heat, the heat exchanger between the solar system and the heat storage system is connected between the solar collector and the heat storage tank, and is used for transferring solar heat to a heat storage medium in the heat storage tank, the heat exchanger between the heat storage system and the desiccant system is connected with the heat exchanger between the solar system and the heat storage system, the heat storage tank and the desiccant regenerator, and is used for transferring heat stored by the heat storage medium to diluted liquid desiccant, the desiccant regenerator is used for recovering the concentration of the diluted liquid desiccant by heating and contacting with air, the auxiliary heater is connected to the pipeline between the heat storage tank and the heat exchanger between the heat storage system and the desiccant system, and is used for supplementing heat energy when the heat storage of the heat storage medium is insufficient, and the heat recovery device is connected with the heat exchanger between the heat storage system and the desiccant system, the desiccant regenerator, the cooling water heat exchanger and the liquid desiccant storage pool, and is used for recovering heat energy between the concentrated desiccant liquid and the diluted liquid desiccant.

[0011] Preferably, the heat storage tank adopts a heat storage ball stacking structure, the inside of the stacked ball is filled with a phase change medium, and the phase change medium includes paraffin.

[0012] As preferred, the air outputted by the first-stage indirect evaporative cooler is divided into two branches, the first branch air is returned to the air inlet channel of the first-stage indirect evaporative cooler as secondary air, and the second branch air flows into the second-stage indirect evaporative cooler.

[0013] As preferred, the solar collector adopts a vacuum tube type / flat plate type / concentrating type heat collector, which is internally filled with a low-boiling point working medium.

[0014] As preferred, the liquid desiccant regeneration device further comprises a concentration sensor and a PID controller, the concentration sensor is arranged in the desiccant regenerator and used for detecting the concentration of the liquid desiccant, the PID controller is connected with the auxiliary heater and the solar water heating circulating pump respectively, the solar water heating circulating pump is connected between the heat storage tank and the heat accumulator and the heat exchanger between the heat accumulator and the desiccant system, and is used for adjusting the cascade control of the solar water heating circulating pump and the auxiliary heating based on the concentration of the liquid desiccant.

[0015] As preferred, the heat accumulator is a counterflow heat exchanger, which is connected with the desiccant regeneration container and used for precooling the concentrated liquid desiccant and heating the diluted desiccant solution.

[0016] As preferred, the system has the following three operation modes:

[0017] Natural cooling mode: when the outdoor temperature is less than or equal to the temperature threshold, only the first-stage indirect evaporative cooler and the second-stage indirect evaporative cooler are operated;

[0018] Mixed cooling mode: when the outdoor temperature is greater than the temperature threshold, the auxiliary cooling device is partially loaded;

[0019] Mechanical refrigeration mode: when the first-stage indirect evaporative cooler and the second-stage indirect evaporative cooler fail or the outdoor temperature is determined as extreme weather, the auxiliary cooling device is fully loaded.

[0020] As preferred, in the liquid desiccant regeneration device, the solar collector, the heat exchanger between the solar system and the heat accumulator, the heat storage tank, and the heat exchanger between the heat accumulator and the desiccant system cooperate to form a heat storage subsystem, and the startup priority of the auxiliary heater is lower than that of the heat storage subsystem.

[0021] When the temperature of the heat storage medium in the heat storage subsystem is greater than or equal to the regeneration set temperature, only the heat storage subsystem is enabled, and when the temperature of the heat storage medium in the heat storage subsystem is less than the regeneration set temperature, the auxiliary heating device is started as an auxiliary of the heat storage subsystem.

[0022] The indirect evaporative cooling system based on solar heat collection and liquid desiccant has the following advantages:

[0023] 1. Energy efficiency leap and energy consumption reduction: The special design of the first-stage indirect evaporative cooler significantly reduces the moisture content of the primary air, enabling the subsequent indirect evaporative cooling process to break through the traditional humidity limit and achieve substantial equal-wetness cooling, greatly reducing the dependence on mechanical refrigeration. By matching the low-temperature solar energy with the desiccant regeneration demand, combined with solution loop waste heat recovery, the regeneration energy consumption is reduced, and the overall energy conversion efficiency reaches the industry-leading level.

[0024] 2. Fundamental expansion of climate adaptability: Liquid desiccant significantly eliminates latent heat load, enabling indirect evaporative cooling to maintain high-efficiency refrigeration capacity in high-temperature and high-humidity environments, breaking through the climate failure boundary of traditional evaporative cooling technology. The two-stage evaporative cooling chain achieves full coverage of basic cooling capacity, and the auxiliary refrigeration device only serves as a supplementary means for extreme conditions, greatly reducing equipment redundancy investment.

[0025] 3. System robustness upgrade: Solution concentration intelligent control and heat storage system architecture ensure continuous output of stable refrigeration capacity under intermittent solar input conditions. Closed desiccant circulation avoids air pollutants, delays solution performance degradation, and extends the service life of key equipment. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0027] The present application will be further described below in conjunction with the drawings.

[0028] Figure 1 For Embodiment 1, a structural diagram of an indirect evaporative cooling system based on solar heat collection and liquid desiccant.

[0029] 1. Solar collector, 2. Heat exchanger between solar system and heat storage system, 3. Heat storage tank, 4. Auxiliary heater, 5. Heat exchanger between heat storage system and desiccant system, 6. Desiccant regenerator, 7. Heat recovery device, 8. Cooling water heat exchanger, 9. Primary cooling water spray unit, 10. Liquid desiccant spray unit, 11. Liquid desiccant storage pool, 12. Secondary cooling water spray unit, 13. Waste water recovery device, 14. Compressor, 15. Condenser, 16. Expansion valve, 17. Cabinet, 18. Auxiliary evaporative coil, 19. Hot return air, 20. Low-temperature supply air, 21. External air inlet, 22. First-stage indirect evaporative cooler, 23. Second-stage indirect evaporative cooler, 24. External air. DETAILED DESCRIPTION

[0030] The present application will be further described below in conjunction with the drawings and specific embodiments so that those skilled in the art can better understand and implement the present application, but the embodiments are not limiting to the present application, and the embodiments and technical features in the embodiments can be combined with each other without conflict.

[0031] The embodiment of the present application provides a kind of indirect evaporative cooling system based on solar heat collection and liquid desiccant, for solving the balance between the independent control demand of temperature and humidity and regenerative energy consumption and the technical problems that the loss exists in energy conversion chain caused by insufficient step utilization of solar full spectrum.

[0032] Embodiment 1:

[0033] The indirect evaporative cooling system based on solar heat collection and liquid desiccant includes a first-stage indirect evaporative cooler 22 based on desiccant, a second-stage indirect evaporative cooler 23 based on desiccant, an auxiliary cooling device, and a liquid desiccant regeneration device driven by solar energy.

[0034] A cooling water heat exchanger 8 and a primary cooling water spraying unit 9 are arranged on the air inlet passage of the first-stage indirect evaporative cooler 22, a liquid desiccant spraying unit 10 is connected to the output pipeline of the cooling water heat exchanger 8, and the liquid desiccant spraying unit 10 is used for deep dehumidification of outdoor air.

[0035] As a specific implementation, external air 21 flows into the air inlet passage of the first-stage indirect evaporative cooler 22 as primary air, is cooled by the primary cooling water spraying unit 9, and the air output by the first-stage indirect evaporative cooler 22 is divided into two branches, the first branch of air is used as secondary air and is returned to the air inlet passage of the first-stage indirect evaporative cooler 22 to spray and evaporatively cool the external air 24, and the second branch of air flows into the second-stage indirect evaporative cooler 23.

[0036] The air inlet passage of the second-stage indirect evaporative cooler 23 is communicated with the air outlet passage of the first-stage indirect evaporative cooler 22, a secondary cooling water spraying unit 12 is arranged on the air inlet passage of the second-stage indirect evaporative cooler 23, the secondary cooling water spraying unit 12 is used for cooling the dry air output by the first-stage indirect evaporative cooler 22, low-temperature air is output, the low-temperature air exchanges heat with hot return air 19 generated by a data center through an auxiliary evaporative coil 18 arranged in the data center, and a waste water recovery device 13 is arranged on the liquid outlet passage of the second-stage indirect evaporative cooler 23.

[0037] The auxiliary evaporative coil 18 is arranged at a cabinet 17 in the data center, and the low-temperature supply air 20 output by the second-stage indirect evaporative cooler 23 flows into the auxiliary evaporative coil 18 and exchanges heat with the hot return air 19 generated near the cabinet 17.

[0038] The auxiliary cooling device comprises a compressor 14, a condenser 15, and an expansion valve 16 connected between the compressor 14 and the condenser 15, and the compressor 14 and the condenser 15 are connected with an auxiliary evaporating coil 18; when the temperature of the low-temperature air output by the secondary indirect evaporative cooler 23 is higher than a threshold value, the auxiliary cooling device is used to provide auxiliary heat exchange for the generated hot return air 19 of the data center.

[0039] The liquid desiccant regeneration device comprises a solar collector 1, a solar system and heat storage system heat exchanger 2, a heat storage tank 3, a heat storage system and desiccant system heat exchanger 5, a desiccant regenerator 6, a regenerator 7, and an auxiliary heater 4, the solar collector 1 is used to collect solar heat, the solar system and heat storage system heat exchanger 2 is connected between the solar collector 1 and the heat storage tank 3, and is used to transfer solar heat to the heat storage medium in the heat storage tank 3, the heat storage system and desiccant system heat exchanger 5 is connected with the solar system and heat storage system heat exchanger 2, the heat storage tank 3, and the desiccant regenerator 6 respectively, and is used to transfer the heat stored by the heat storage medium to the diluted liquid desiccant, the desiccant regenerator 6 is used to restore the concentration of the diluted liquid desiccant by heating and contacting with air, the auxiliary heater 4 is connected to the pipeline between the heat storage tank 3 and the heat storage system and desiccant system heat exchanger 5, and is used to supplement heat energy when the heat storage of the heat storage medium is insufficient, and the regenerator 7 is connected with the heat storage system and desiccant system heat exchanger 5, the desiccant regenerator 6, the cooling water heat exchanger 8, and the liquid desiccant storage tank 11 respectively, and is used to recover heat energy between the concentrated desiccant liquid and the diluted liquid desiccant.

[0040] As a specific implementation of the liquid desiccant regeneration device, the heat storage tank adopts a heat storage ball stacking structure, the inside of the stacked ball is filled with a phase change medium, and the phase change medium comprises paraffin. The solar collector 1 adopts a vacuum tube type / flat plate type / concentrated type heat collector, and the inside is filled with a low-boiling-point working medium.

[0041] The liquid desiccant regeneration device further comprises a concentration sensor and a PID controller, the concentration sensor is arranged in the desiccant regenerator 6 and is used to detect the concentration of the liquid desiccant, the PID controller is connected with the auxiliary heater 4 and a solar hot water circulating pump respectively, the solar hot water circulating pump is connected between the heat storage tank 3 and the heat storage system and desiccant system heat exchanger 5, and is used to adjust the cascade control of the solar hot water circulating pump and the auxiliary heating based on the concentration of the liquid desiccant.

[0042] The regenerator 7 is a counterflow heat exchanger, the regenerator 7 is connected with the desiccant regeneration container, and is used to precool the concentrated liquid desiccant and heat the diluted desiccant solution.

[0043] In this embodiment, the system has the following three operation modes:

[0044] (1) Natural cooling mode: When the outdoor temperature is less than or equal to the temperature threshold, only the first stage indirect evaporative cooler 22 and the second stage indirect evaporative cooler 23 are operated;

[0045] (2) Hybrid cooling mode: When the outdoor temperature is greater than the temperature threshold, the auxiliary cooling device is operated in partial load;

[0046] (3) Mechanical refrigeration mode: When the first stage indirect evaporative cooler 22 and the second stage indirect evaporative cooler 23 fail or the outdoor temperature is determined to be extreme weather, the auxiliary cooling device is operated in full load.

[0047] In the liquid desiccant regeneration device, the solar collector 1, the heat exchanger 2 between the solar system and the heat storage system, the heat storage tank 3, and the heat exchanger 5 between the heat storage system and the desiccant system cooperate to form a heat storage subsystem. The priority of starting the auxiliary heater 4 is lower than that of the heat storage subsystem. When the temperature of the heat storage medium in the heat storage subsystem is greater than or equal to the regeneration set temperature, only the heat storage subsystem is enabled. When the temperature of the heat storage medium in the heat storage subsystem is less than the regeneration set temperature, the auxiliary heating device is started as an auxiliary of the heat storage subsystem.

[0048] The air handling, liquid desiccant circuit, and data center cooling process of the system are described as follows.

[0049] The outdoor primary air first enters the inlet air passage of the first stage indirect evaporative cooler 22, and liquid desiccant is sprayed in the inlet air passage to absorb the moisture in the primary air 24. At the outlet, the primary air is divided into two parts: one part returns as the secondary air of the first stage indirect evaporative cooler 22, which carries away the heat in the primary air 24 under the action of spraying water and evaporation; the other part flows into the secondary air passage of the second stage indirect evaporative cooler 23.

[0050] The secondary air passages of the first stage indirect evaporative cooler 22 and the second stage indirect evaporative cooler 23 are continuously sprayed with water to form an evaporative water film that carries away heat from the primary air.

[0051] The dehumidification of the primary air not only increases its evaporative cooling potential in the second stage indirect evaporative cooler 23, but also, due to the recirculation of a part of the air as the secondary air of the first stage indirect evaporative cooler 22, the primary air undergoes indirect evaporative cooling. Compared with simply using outdoor natural air, the temperature of the secondary air in the first stage indirect evaporative cooler 22 is lower.

[0052] This dehumidified air is used as the secondary air of the second stage indirect evaporative cooler 23, which can indirectly absorb the heat of the hot air circulating out of the data center through the indirect evaporative heat exchange coil. If the outlet air temperature of the second stage indirect evaporative cooler 23 still does not meet the required supply temperature, the auxiliary cooling device is activated to ensure that the supply air temperature remains within the target range.

[0053] In the air treatment process, the system dynamically adjusts according to the outdoor wet-bulb temperature:

[0054] (1) When the wet-bulb temperature is less than or equal to the first threshold value, the desiccant system and the first-stage spray system are turned off, and cooling is directly performed through the second-stage indirect evaporative cooling system;

[0055] (2) When the first threshold value is less than the wet-bulb temperature and the wet-bulb temperature is less than or equal to the second threshold value, the desiccant system is turned off, and the system cools through the first-stage indirect evaporative cooler 22 and the second-stage indirect evaporative cooler 23;

[0056] (3) When the wet-bulb temperature is greater than the second threshold value, the desiccant system is turned on, and the entire system is turned on.

[0057] In addition, the auxiliary cooling device of the data center also has three operating modes. When the outdoor temperature is low, the outlet temperature of the indirect evaporative cooler can meet the requirements, and the data center is directly cooled, which is the natural cooling mode. When the outdoor temperature is high, the auxiliary cooling device operates at non-full power, and the indirect evaporative cooling system and the compressor 14 system operate together, which is the hybrid cooling mode. When the outdoor temperature and humidity are extremely high, or the indirect evaporative system fails, the auxiliary refrigeration system operates at full load alone, and alone cools the data center, which is the mechanical refrigeration mode.

[0058] The liquid desiccant enters the first-stage indirect evaporative cooler 22, absorbs moisture, and the concentration of the liquid desiccant decreases, and flows into the liquid desiccant heat storage tank 3. Then, before entering the heat exchanger of the solar water heating system, it is preheated by the solution regenerator 7.

[0059] The solar heat collection system adopts a phase change heat pipe structure. During the day, the solar heat collector absorbs solar heat, heats the heat exchange medium inside it, and flows into the heat exchanger between the solar system and the energy storage system from the upper loop to exchange heat inside the heat exchanger, heating the heat storage medium inside the heat storage system. The heat exchange medium inside the solar system cools down and returns to the solar heat collector for recycling. The solar heat collector includes but is not limited to vacuum tube type, flat plate type, and concentrating type structures.

[0060] The heat exchanger between the solar system and the heat storage system provides hot water for the heat storage system through heat exchange, and the excess heat is stored in the heat storage tank (the heat storage tank adopts a heat storage ball stacking structure, and the stacked balls are filled with phase change medium such as paraffin).

[0061] The dilute liquid desiccant solution is heated by hot water through the heat storage system and the desiccant system heat exchanger 5. At night, when solar radiation is not available, the heat stored in the heat storage tank is released for heating the solution, and if the water temperature is insufficient, the auxiliary heater 4 is started. The heated dilute solution is sent to the regenerator, where fresh air is used to regenerate the desiccant, increasing its concentration. After regeneration, the concentrated solution is cooled by the regenerator 7 and the cooling water heat exchanger 8, and then sprayed again for reuse.

[0062] The system of the embodiment is based on the IEC system of the liquid desiccant integrated with the traditional IEC system, which effectively solves the problems of serious performance degradation and high energy consumption by using solar energy to assist the regeneration of the desiccant, prolongs the utilization time of natural cooling, and reduces the dependence on mechanical refrigeration.

[0063] The above describes in detail the indirect evaporative cooling system based on solar heat collection and liquid desiccant provided by the present application. The principles and implementation modes of the present application are described by applying specific examples. The above description of the embodiments is only used to help understand the method of the present application and its core idea. Meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range will be changed. In summary, the content of the specification should not be understood as a limitation of the present application.

Claims

1. An indirect evaporative cooling system based on solar thermal collection and liquid desiccant, characterized in that, It includes a desiccant-based primary indirect evaporative cooler, a desiccant-based secondary indirect evaporative cooler, an auxiliary cooling device, and a solar-driven liquid desiccant regeneration device; A cooling water heat exchanger and a primary cooling water spray unit are installed on the air inlet channel of the primary indirect evaporative cooler. A liquid desiccant spray unit is connected to the air duct of the cooling water heat exchanger for dehumidifying the outdoor primary air. The primary cooling water spray unit is used for preliminary cooling of the outdoor primary air. A liquid desiccant storage tank is installed on the liquid outlet channel of the primary indirect evaporative cooler. The air inlet channel of the secondary indirect evaporative cooler is connected to the air outlet channel of the primary indirect evaporative cooler. A secondary cooling water spray unit is deployed on the air inlet channel of the secondary indirect evaporative cooler to cool the dry air output from the primary indirect evaporative cooler and output low-temperature air. The low-temperature air exchanges heat with the hot return air generated by the data center through the auxiliary evaporative coil deployed in the data center. A waste water recovery device is deployed on the liquid outlet channel of the secondary indirect evaporative cooler. The auxiliary cooling device includes a compressor, a condenser, and an expansion valve connected between the compressor and the condenser. Both the compressor and the condenser are connected to the auxiliary evaporator coil. When the temperature of the low-temperature air output by the secondary indirect evaporator is higher than the threshold, the auxiliary cooling device is used to provide auxiliary heat exchange for the hot return air generated by the data center. The liquid desiccant regeneration device includes a solar collector, a converter between the solar system and the thermal storage system, a thermal storage tank, a heat exchanger between the thermal storage system and the desiccant system, a desiccant regenerator, a regenerator, and an auxiliary heater. The solar collector collects solar heat. The heat exchanger between the solar system and the thermal storage system is connected between the solar collector and the thermal storage tank to transfer solar heat to the thermal storage medium in the tank. The heat exchanger between the thermal storage system and the desiccant system is connected to the heat exchanger between the solar system and the thermal storage system, the thermal storage tank, and the desiccant regenerator, respectively. The heat exchanger is used to transfer the heat stored in the heat storage medium to the diluted liquid desiccant. The desiccant regenerator is used to restore the concentration of the diluted liquid desiccant by heating and contacting it with air. The auxiliary heater is connected to the pipeline between the heat storage tank and the heat exchanger between the heat storage system and the desiccant system, and is used to supplement the heat energy when the heat storage medium is insufficient. The regenerator is connected to the heat exchanger between the heat storage system and the desiccant system, the desiccant regenerator, the cooling water heat exchanger, and the liquid desiccant storage tank, and is used to recover heat energy between the concentrated desiccant liquid and the diluted liquid desiccant.

2. The hybrid indirect evaporative cooling system according to claim 1, characterized in that, The thermal storage tank adopts a thermal storage ball stacking structure, and the inside of the stacked balls is filled with a phase change medium, which includes paraffin.

3. The hybrid indirect evaporative cooling system according to claim 1, characterized in that, The air output from the primary indirect evaporative cooler is divided into two branches. The first branch of air is returned to the intake channel of the primary indirect evaporative cooler as secondary air, while the second branch of air flows into the secondary indirect evaporative cooler.

4. The hybrid indirect evaporative cooling system according to claim 1, characterized in that, The solar collector uses a vacuum tube / flat plate / concentrating collector, filled with a low-boiling-point working fluid.

5. The hybrid indirect evaporative cooling system according to claim 1, characterized in that, The liquid desiccant regeneration device also includes a concentration sensor and a PID controller. The concentration sensor is deployed inside the desiccant regenerator to detect the concentration of the liquid desiccant. The PID controller is connected to the auxiliary heater and the solar water heating circulation pump, respectively. The solar water heating circulation pump is connected between the heat storage tank and the heat exchanger between the heat storage system and the desiccant system, and is used to adjust the cascade control of the solar water heating circulation pump and the auxiliary heater based on the concentration of the liquid desiccant.

6. The hybrid indirect evaporative cooling system according to claim 1, characterized in that, The regenerator is a counter-current heat exchanger, which is connected to the desiccant regeneration container and is used for pre-cooling concentrated liquid desiccant and heating diluted desiccant solution.

7. The hybrid indirect evaporative cooling system according to claim 1, characterized in that, The system has the following three operating modes: Natural cooling mode: When the outdoor temperature is less than or equal to the temperature threshold, only the first-stage indirect evaporative cooler and the second-stage indirect evaporative cooler operate; Hybrid cooling mode: When the outdoor temperature exceeds the temperature threshold, the auxiliary cooling device operates at partial load; Mechanical refrigeration mode: When the primary and secondary indirect evaporative coolers fail or the outdoor temperature is determined to be extreme weather, the auxiliary cooling device operates at full load.

8. The hybrid indirect evaporative cooling system according to claim 1, characterized in that, In the liquid desiccant regeneration device, the solar collector, the heat exchanger between the solar system and the heat storage system, the heat storage tank, and the heat exchanger between the heat storage system and the desiccant system work together to form a heat storage subsystem. The auxiliary heater has a lower start-up priority than the heat storage subsystem. When the temperature of the heat storage medium in the heat storage subsystem is greater than or equal to the regeneration set temperature, only the heat storage subsystem is activated. When the temperature of the heat storage medium in the heat storage subsystem is less than the regeneration set temperature, the auxiliary heating device is activated as an auxiliary to the heat storage subsystem.

Images