Dual return water end air conditioning and data center dual return water cooling system

Abstract

The present application relates to a kind of double-back water terminal air conditioner and data center double-back water cooling system, double-back water terminal air conditioner includes shunt device containing flow regulating valve, first surface condenser and second surface condenser, water inlet, terminal secondary pump, low-temperature backwater inlet, high-temperature backwater inlet, return air temperature sensor, high-temperature backwater temperature sensor, supply air temperature sensor, controller.By being set in double-back water terminal air conditioner inside two surface condensers or being set in the middle of multilayer surface condenser shunt branch pipe, by adjusting the flow of flow regulating valve, so that the outlet temperature of high-temperature backwater inlet is higher than outdoor air wet bulb temperature and close to double-back water terminal air conditioner return air temperature, so that the low-temperature chilled backwater shunted from the middle is sent into low-temperature backwater pipeline and directly delivered to chiller evaporator, and the high-temperature backwater from high-temperature backwater inlet then enters high-temperature backwater pipeline, and then directly enters high-efficiency closed cooling tower and is fully naturally cooled, greatly reduce the energy consumption of entire data center water cooling system.

Description

Technical Field

[0001] This invention relates to the field of data center cooling technology, specifically to a dual-return water terminal air conditioner and a data center dual-return water cooling system that can make full use of natural cold sources. Background Technology

[0002] With the rapid development of industries such as the Internet, artificial intelligence, the Internet of Things, and big data, global data centers are trending towards larger scales, with continuously increasing power density per rack. The next generation of data centers is characterized by larger scale, higher density, more demanding cooling requirements, and the emergence of localized overheating as a pressing issue. Looking at the development of data centers in China, due to the increased power density, the next generation of data centers, especially large-scale data centers, primarily adopts more efficient water-cooled air conditioning systems to meet the ever-increasing cooling demands.

[0003] In existing data center air conditioning systems, the return air design temperature on the server room side is typically above 35℃, while the wet-bulb temperature in most parts of China during summer is usually below 29℃. This creates conditions for utilizing natural cooling sources. However, common data center cooling systems often use a design with 12-15℃ inlet water and 18-21℃ outlet water. For this type of data center to achieve energy savings and reduce consumption through water-side natural cooling, the outdoor wet-bulb temperature must be lower than the outlet water temperature. This results in the data center air conditioning system operating in mechanical cooling mode most of the time, leading to persistently high energy consumption. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention provides a dual-return water terminal air conditioner with a built-in terminal secondary pump and flow regulating valve, and a data center dual-return water cooling system based on this dual-return water terminal air conditioner. By installing two surface coolers inside the terminal air conditioner or by installing a branch pipe between multiple surface coolers, the flow rate of the branch regulating valve is adjusted so that hot water flowing from the high-temperature return water inlet, which is higher than the outdoor air wet-bulb temperature and close to the terminal air conditioner's return air temperature, enters the high-temperature return water pipeline. This high-temperature return water then directly enters a high-efficiency closed-loop cooling tower for sufficient natural cooling. Low-temperature chilled return water, which is not higher than the chiller's operating temperature limit and flows from the intermediate low-temperature return water inlet, enters the low-temperature return water pipeline and is directly transported to the chiller evaporator. This configuration ensures that the cooling performance of the terminal air conditioners meets the set requirements while the return water entering the chiller does not exceed the chiller's operating temperature limit. This increases the maximum outlet water temperature of the terminal air conditioners, allowing the water-cooled air conditioning system to directly utilize natural cold sources in summer. When the outlet water temperature of the high-efficiency closed-circuit cooling tower used for pre-cooling is lower than the chiller's operating temperature limit, the diversion function is shut off, and all the air conditioner water enters the high-temperature return water pipeline and then the high-efficiency closed-circuit cooling tower, significantly reducing the energy consumption of the entire data center water cooling system. By installing a terminal secondary pump in the dual-return terminal air conditioner, precise adjustment and control of cooling capacity can be achieved, improving the efficiency of the data center water cooling system.

[0005] The technical solution of the present invention is as follows:

[0006] A dual-return water terminal air conditioner,

[0007] Includes a housing (110), a return air inlet (121), an air supply outlet (122), a fan (160), a flow divider with a flow regulating valve, a first surface cooler (131), a second surface cooler (132), a water inlet (171), a terminal secondary pump (150), a low-temperature return water inlet (172), a high-temperature return water inlet (173), a return air temperature sensor (181), a high-temperature return water temperature sensor (182), an air supply temperature sensor (183), and a controller;

[0008] The diversion device is a three-way regulating device. The inlet of the diversion device is connected to the outlet of the first surface cooler (131), the first outlet of the diversion device is connected to the inlet of the second surface cooler (132), and the second outlet of the diversion device is connected to the low temperature return port (172).

[0009] The return air inlet (121), the second surface cooler (132), the first surface cooler (131), the fan (160), and the air outlet (122) are arranged sequentially along the airflow direction of the dual-return water terminal air conditioner (100);

[0010] The return air temperature sensor (181) is located in the middle of the return air inlet (121) and is used to measure the return air temperature of the dual-return water terminal air conditioner (100); the high-temperature water temperature sensor (182) is located between the outlet of the second surface cooler (132) and the high-temperature return water inlet (173) and is used to measure the high-temperature chilled water temperature of the dual-return water terminal air conditioner (100); the supply air temperature sensor (183) is located in the middle of the supply air inlet (122) and is used to measure the supply air temperature of the dual-return water terminal air conditioner (100).

[0011] The controller adjusts the flow rate of the high-temperature chilled water in the high-temperature return port (173) by adjusting the flow rate of the flow regulating valve, so that the temperature of the high-temperature chilled water in the high-temperature return port is higher than the outdoor air wet-bulb temperature and close to the return air temperature of the dual-return terminal air conditioner; the controller controls the speed of the fan (160) so that the return air temperature of the dual-return terminal air conditioner (100) reaches the set value.

[0012] The terminal secondary pump (150) is located between the first surface cooler (131) and the water inlet (171); the controller adjusts the water flow of the dual return water terminal air conditioner by controlling the rotation speed of the terminal secondary pump (150), so that the air supply temperature of the dual return water terminal air conditioner (100) reaches the set value.

[0013] The dual-return water terminal air conditioner of the present invention can also be implemented in a single surface cooler using a multi-layer surface cooler, as shown in the following technical solution:

[0014] A dual-return water terminal air conditioner, characterized in that:

[0015] Includes a housing (110), a return air inlet (121), an air supply outlet (122), a fan (160), a flow distribution device containing a flow regulating valve and several branch pipes, a multi-layer surface cooler connected to the several branch pipes, a water inlet (171), a terminal secondary pump (150), a low-temperature return water inlet (172), a high-temperature return water inlet (173), a return air temperature sensor (181), a high-temperature return water temperature sensor (182), an air supply temperature sensor (183), and a controller;

[0016] The multi-layer surface cooler is composed of several coils. A branch pipe is set at the end of any coil in the middle through a Y-shaped tee. All the branch pipes are connected to the branch pipe. The multi-layer surface cooler is divided into a lower half (133a) and an upper half (133b) of the surface cooler at the branch pipe along the direction of the coil.

[0017] The branch pipe diverts a portion of the chilled water from the coil of the surface cooler. The chilled water diverted from the branch pipe flows back into the branch pipe and then flows out through the flow regulating valve.

[0018] The return air inlet (121), the upper part of the multi-layer surface cooler (133b), the upper part of the multi-layer surface cooler (133a), the fan (160), and the air outlet (122) are arranged sequentially along the airflow direction of the dual-return water terminal air conditioner (100);

[0019] The return air temperature sensor (181) is located in the middle of the return air inlet (121) and is used to measure the return air temperature of the dual-return water terminal air conditioner (100); the high-temperature water temperature sensor (182) is located between the water outlet of the upper part (133b) of the surface cooler and the high-temperature return water inlet (173) and is used to measure the high-temperature chilled water temperature of the dual-return water terminal air conditioner (100); the supply air temperature sensor (183) is located in the middle of the supply air inlet (122) and is used to measure the supply air temperature of the dual-return water terminal air conditioner (100).

[0020] The controller regulates the flow rate of the high-temperature chilled water at the high-temperature return port (173) by adjusting the flow rate of the flow regulating valve, so that the temperature of the high-temperature chilled water at the high-temperature return port is higher than the outdoor air wet-bulb temperature and close to the return air temperature of the dual-return terminal air conditioner; the controller controls the speed of the fan (160) to make the return air temperature of the dual-return terminal air conditioner (100) reach the set value;

[0021] The terminal secondary pump (150) is located between the lower part (133a) of the multi-layer surface cooler and the water inlet (171). The controller adjusts the water flow of the dual-return terminal air conditioner by controlling the rotation speed of the terminal secondary pump (150) so that the air supply temperature of the dual-return terminal air conditioner (100) reaches the set value.

[0022] This invention also provides a data center dual-return water cooling system based on dual-return water terminal air conditioning, the specific technical solution of which is as follows:

[0023] A dual-return water cooling system for data centers,

[0024] It includes several dual-return water terminal air conditioners (100) as described in any one of claims 1-4, several cooling towers (200), several chiller units (300), several primary pumps (151), water supply network (410), low temperature return water network (420), and high temperature return water network (430).

[0025] The inlet (171) of any of the dual-return water terminal air conditioners (100) is connected to the water supply network (410); the low-temperature return water inlet (172) of any of the dual-return water terminal air conditioners (100) is connected to the inlet of the low-temperature return water network (420); and the high-temperature return water inlet (173) of any of the dual-return water terminal air conditioners (100) is connected to the inlet of the high-temperature return water network (430).

[0026] The inlet end of any of the cooling towers (200) is connected to the high-temperature return water network (430); the outlet end of any of the cooling towers (200) is connected to the low-temperature return water network (420).

[0027] The inlet of any of the primary pumps (151) is connected to the low-temperature return water network (420), and the outlet of the primary pump (151) is connected to the evaporator of the chiller (300); the outlet of any of the chillers (300) is connected to the water supply network (410).

[0028] The outlet water temperature of the cooling tower (200) is lower than the maximum return water temperature that the chiller (300) can withstand; when the outlet water temperature of the cooling tower (200) is higher than the maximum outlet water temperature that the chiller (300) can withstand, the flow diversion device is adjusted so that the water flow rate of the high temperature return water port is zero.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] (1) Data centers can utilize natural cold sources (usually cooling towers) to directly cool the high-temperature chilled water of the second surface cooler (or the upper part of the multi-layer surface cooler) of the dual-return water terminal air conditioner under summer conditions. The high-temperature chilled water is close to the return air temperature of 35°C (the outdoor wet-bulb temperature in most parts of China is below 29°C in summer). The high-temperature chilled water is cooled by the cooling tower with high efficiency, and the energy consumption of the entire data center water-cooled air conditioning system is low.

[0031] (2) The dual-return water terminal air conditioner uses a built-in terminal secondary pump to regulate the water inlet of the dual-return water terminal air conditioner instead of the traditional proportional integral valve to control the chilled water flow of the dual-return water terminal air conditioner. This improves the water inlet control progress of the dual-return water terminal air conditioner and reduces the energy consumption in the water transportation process. This improves the cooling capacity control accuracy and cooling efficiency of the dual-return water terminal air conditioner and reduces the energy consumption of the entire data center water-cooled air conditioner.

[0032] (3) The data center dual-return water cooling system is equipped with a pressure relief module between the water supply network and the low-temperature return water network, and the speed of the primary pump is adjusted so that the pressure difference between the water supply network and the low-temperature return water network is close to zero. In this way, a large pressure difference is not required to achieve continuous water supply between the water supply network and the low-temperature return water network, and both the primary pump and the secondary pump can work at a lower load. The pump efficiency is high and it is more energy-efficient than the traditional solution. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of the first embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of the structure of a dual-return water terminal air conditioner according to the first embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram of another dual-return water terminal air conditioner in the first embodiment of the present invention;

[0036] Figure 4 This is a schematic diagram of the structure of a dual-return water terminal air conditioner according to the second embodiment of the present invention;

[0037] Figure 5 This is a schematic diagram of the structure of the third embodiment of the present invention;

[0038] 100 Dual-return water terminal air conditioner; 110 Outer casing; 121 Return air inlet; 122 Supply air inlet; 131 First surface cooler; 132 Second surface cooler; 133a Lower part of multi-layer surface cooler; 133b Upper part of multi-layer surface cooler; 141 Electric three-way diversion regulating valve; 1421 Diversion three-way; 1422 Electric two-way regulating valve; 150 Terminal secondary pump; 151 Primary pump; 160 Fan; 171 Water inlet; 172 Low-temperature return water inlet; 173 High-temperature return water inlet; 181 Return air temperature sensor; 182 High-temperature return water temperature sensor; 183 Supply air temperature sensor;

[0039] 200 Cooling tower; 300 Chiller unit; 410 Water supply network; 420 Low temperature return water network; 430 High temperature return water network; 500 Pressure relief module; 600 Water storage cooling device. Detailed Implementation

[0040] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0041] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0043] The invention will now be further explained with reference to the accompanying drawings.

[0044] Example 1:

[0045] like Figure 1 The image shows a specific application case of a water-cooled system, including dual-return water terminal air conditioners and a dual-return water network, in a data center. The data center dual-return water system includes several dual-return water terminal air conditioners 100, several cooling towers 200, several chiller units 300, several primary pumps 151, a water supply network 410, a low-temperature return water network 420, and a high-temperature return water network 430.

[0046] The inlet 171 of any dual-return water terminal air conditioner 100 is connected to the water supply network 410; the low-temperature return water inlet 172 of any dual-return water terminal air conditioner 100 is connected to the inlet of the low-temperature return water network 420; and the high-temperature return water inlet 173 of any dual-return water terminal air conditioner 100 is connected to the inlet of the high-temperature return water network 430.

[0047] The inlet of any cooling tower 200 is connected to the high-temperature return water network 430; the outlet of any cooling tower 200 is connected to the low-temperature return water network 420; the outlet water temperature of the cooling tower 200 does not exceed the maximum return water temperature tolerance of the chiller 300. When the outlet water temperature of the cooling tower 200 is higher than the maximum outlet water temperature that the chiller can withstand, the flow distribution device is adjusted to make the water flow at the high-temperature return water inlet zero.

[0048] The inlet of any primary pump 151 is connected to the low-temperature return water network 420, and the outlet of any chiller is connected to the water supply network 410; the primary pump 151 regulates the water supply of the water supply network 410, thereby regulating the total cooling capacity of the entire data center dual return water cooling system.

[0049] like Figure 2As shown, the dual-return water terminal air conditioner 100 includes a housing 110, a return air inlet 121, a supply air inlet 122, a fan 160, a flow divider with a flow regulating valve, a first surface cooler 131 and a second surface cooler 132 respectively connected to the flow divider, a water inlet 171, a terminal secondary pump 150, a low-temperature return water inlet 172, a high-temperature return water inlet 173, a return air temperature sensor 181, a high-temperature return water temperature sensor 182, a supply air temperature sensor 183, and a controller.

[0050] In this embodiment, the diversion device is a three-way diversion device. The inlet end of the diversion device is connected to the outlet end of the first surface cooler 131, the first outlet end of the diversion device is connected to the inlet end of the second surface cooler (132), and the second outlet end of the diversion device is connected to the low temperature return port (172).

[0051] The return air vent 121, the second surface cooler 132, the first surface cooler 131, the fan 160, and the supply air vent 122 are arranged sequentially along the airflow direction of the dual return water terminal air conditioner 100.

[0052] The flow divider adjusts the flow rate of the high-temperature chilled water at the high-temperature return port 173 by regulating the flow rate of the flow regulating valve. By adjusting the flow rate of the high-temperature chilled water at the high-temperature return port, the flow divider ensures that the temperature of the high-temperature chilled water at the high-temperature return port is higher than the outdoor air wet-bulb temperature and close to the return air temperature of the dual-return terminal air conditioner.

[0053] The controller controls the speed of fan 160 to ensure the return air temperature of the dual-return water terminal air conditioner 100 reaches the set value. In data center applications, this dual-return water terminal air conditioner can be used for room-level air conditioning or inter-row air conditioning.

[0054] The terminal secondary pump 150 is located between the first surface cooler 131 and the water inlet 171. The controller adjusts the water inlet flow by controlling the speed of the terminal secondary pump 150 so that the air supply temperature of the dual return water terminal air conditioner 100 reaches the set value.

[0055] Preferably, the dual-return water terminal air conditioner also includes a check valve, which is located between the first surface cooler 131 and the terminal secondary pump 150. This check valve is used to prevent water from flowing back into the terminal secondary pump during a water outage, thus preventing damage to the terminal secondary pump.

[0056] In the entire water-cooling system, the dual-return terminal air conditioners utilize built-in secondary pumps to regulate the inlet water flow instead of the traditional proportional-integral valve method. This improves the inlet water control efficiency and reduces energy consumption during water transport, thereby enhancing the terminal cooling capacity control accuracy and cooling efficiency of the water-cooling system. Furthermore, the precise control of terminal cooling capacity via the secondary pumps enables refined cooling control of the data center, allowing for real-time and accurate matching of terminal cooling capacity based on dynamic changes in the data center's operating load.

[0057] This embodiment establishes a water supply network, a low-temperature return water network, and a high-temperature return water network. The water supply network supplies chilled water from the chiller to all dual-return water terminal air conditioners. The low-temperature return water network collects the low-temperature chilled water from the low-temperature return inlets of all dual-return water terminal air conditioners and the cooling water from all cooling towers, and supplies this collected water to the chiller to produce the chilled water needed for the dual-return water terminals. The high-temperature return water network collects the heated high-temperature chilled water from the high-temperature return inlets of all dual-return water terminal air conditioners and supplies it to the cooling towers for cooling, making full use of the high-temperature chilled water obtained from the high-temperature return water network for natural cooling.

[0058] This embodiment improves the cooling efficiency of the entire water cooling system by setting up dual return water terminal air conditioners and dual return water pipe networks in the water cooling system. The high-temperature return water pipe network collects the high-temperature chilled water produced by the dual return water terminal air conditioners and supplies it to the cooling tower for cooling, making full use of natural cooling.

[0059] Figure 2 This is a schematic diagram of a dual-return water terminal air conditioner according to the first embodiment of the present invention. The dual-return water terminal air conditioner 100 includes a housing 110, a return air inlet 121, a supply air inlet 122, a fan 160, a first surface cooler 131, a flow distribution device, a second surface cooler 132, a return air temperature sensor 181, a high-temperature return water temperature sensor 182, a supply air temperature sensor 183, a controller, a water inlet 171, a low-temperature return water inlet 172, and a high-temperature return water inlet 173. The controller is not shown in the figure and is located in a corresponding position inside the dual-return water terminal air conditioner. In data center applications, this dual-return water terminal air conditioner can be used as a room air conditioner or a row air conditioner in a data center.

[0060] The inlet of the diversion device is connected to the outlet of the first surface cooler 131, the first outlet of the diversion device is connected to the inlet of the second surface cooler 132, and the second outlet of the diversion device is connected to the low-temperature return port 172. In this embodiment, the diversion device is preferably an electric three-way diversion regulating valve 141, which is a three-way valve with one inlet and two outlets, including an inlet, a first outlet, and a second outlet.

[0061] The return air vent 121, the second surface cooler 132, the first surface cooler 131, the fan 160, and the supply air vent 122 are arranged sequentially along the airflow direction of the dual return water terminal air conditioner 100.

[0062] The controller controls the speed of the fan 160 to make the return air temperature of the dual return water terminal air conditioner 100 reach the set value; the controller controls the diversion device to adjust the water flow rate into the second surface cooler 132 so that the outlet water temperature of the second surface cooler 132 reaches the set value.

[0063] The set value of the outlet water temperature of the second surface cooler 132 is greater than the outdoor air wet-bulb temperature.

[0064] The first surface cooler serves as the active cooling source during summer operation. Under summer conditions, it can share most of the cooling capacity of the entire dual-return water terminal air conditioner, enabling the entire dual-return water terminal air conditioner to reach its designed cooling capacity even at the highest wet-bulb temperature in the environment.

[0065] The return air temperature sensor 181 is located in the middle area of ​​the return air inlet 121 to monitor the return air temperature.

[0066] The air supply temperature sensor 183 is located in the middle area of ​​the air supply outlet 122 to monitor the air supply temperature.

[0067] The high-temperature return water temperature sensor 182 is installed inside the pipe connecting the outlet of the second surface cooler 132 and the high-temperature return water port 173, and is used to monitor the outlet water temperature of the second surface cooler, that is, the high-temperature chilled water temperature of the dual return water terminal air conditioner (100).

[0068] The controller is installed inside the dual-return water terminal air conditioner to collect temperature signals from various sensors in real time. At the same time, based on temperature changes, it adopts corresponding control strategies to ensure that the return air temperature, supply air temperature, and high-temperature chilled water temperature at the high-temperature return water inlet of the dual-return water terminal air conditioner reach the set values.

[0069] In this embodiment, the outlet water temperature of the second surface cooler is higher than the outdoor air wet-bulb temperature, and the high-temperature chilled water flowing out of the surface cooler can be directly cooled by a natural cold source. In this embodiment, a cooling tower is preferably used for cooling. Furthermore, a closed-loop cooling tower can be used for cooling; compared to an open-loop cooling tower water cooling system, the entire system is more water-efficient.

[0070] Preferably, the fan 160 is an EC fan.

[0071] Preferably, the cooling tower 200 is a closed cooling tower.

[0072] Here, this embodiment realizes a dual-return water terminal air conditioner that can generate high-temperature chilled water and low-temperature chilled water by including two surface coolers and an electric three-way diversion regulating valve. Furthermore, through the further configuration of the dual-return water network, cooling tower, and chiller, the high-temperature chilled water is naturally cooled by the cooling tower, which greatly reduces and improves the energy consumption of the data center water cooling system.

[0073] Figure 3 This is a schematic diagram of another dual-return water terminal air conditioner in the first embodiment of the present invention. Figure 2 In contrast, the dual-return water terminal air conditioning diversion device consists of a diversion tee 1421 and an electric two-way regulating valve 1422.

[0074] Diverter tee 1421 is a T-type or Y-type diverter tee, with one inlet and two outlets. The electric two-way regulating valve 1422 is connected to the outlet of the diverter tee 1421.

[0075] Furthermore, such as Figure 3 As shown, the electric two-way regulating valve 1422 is connected to the second water outlet connector of the diverting three-way valve 1421. In this way, by adjusting the flow rate of the electric two-way regulating valve 1422, the water outlet flow rate of the first surface cooler is precisely controlled, and the water inlet flow rate of the second surface cooler is also made to be the difference between the water inlet flow rate of the first liquid cooling module and the water outlet flow rate of the first surface cooler.

[0076] In other embodiments, the electric two-way regulating valve 1422 is connected to the first water outlet connector of the diverting three-way valve 1421. In this way, the inlet water flow of the second surface cooler is precisely controlled by adjusting the flow of the electric two-way regulating valve 1422, and the outlet water flow of the first surface cooler is also made to be the difference between the inlet water flow of the first liquid cooling module and the inlet water flow of the second surface cooler.

[0077] Here, this embodiment realizes a dual-return water terminal air conditioner that can generate high-temperature chilled water and low-temperature chilled water by using a diversion device consisting of two surface coolers, a diversion tee and an electric two-way regulating valve. Furthermore, through the further configuration of the dual-return water network, cooling tower and chiller, the high-temperature chilled water is naturally cooled by the cooling tower, which greatly reduces and improves the energy consumption of the data center water cooling system.

[0078] Example 2:

[0079] like Figure 4 As shown, the difference between Embodiment 2 and Embodiment 1 is that the dual-return water cooling system's dual-return water terminal air conditioner is not composed of two surface coolers, but of a multi-layer surface cooler. The multi-layer surface cooler contains a distribution pipe and a main branch pipe; the distribution device includes a flow regulating valve.

[0080] The multi-layer surface cooler of the dual-return terminal air conditioner consists of several coils. At the end of the middle layer of any coil, a branch pipe is set through a Y-shaped tee. The branch pipes converge and connect to the main branch pipe. The multi-layer surface cooler of the dual-return terminal air conditioner is divided into a lower part (133a) and an upper part (133b) of the surface cooler at the branch pipe along the coil direction. The lower part 133a of the surface cooler has the same function as the first surface cooler in Embodiment 1 or Embodiment 2, and the upper part 133b of the surface cooler has the same function as the second surface cooler in Embodiment 1 or Embodiment 2.

[0081] The diversion pipe and diversion branch pipe are used to divert a portion of the chilled water from the lower part 133a of the surface cooler through the diversion branch pipe into the diversion pipe, and then into the flow regulating valve. The flow rate of the water diverted into the flow regulating valve is adjusted by the flow regulating valve, which directly adjusts the return water volume of the low-temperature chilled water in this embodiment, and also adjusts the flow rate of the chilled water flowing into the upper part 133b of the surface cooler.

[0082] The chilled water from the dual-return terminal air conditioner 100 is divided into several streams through the inlet and enters each coil. In the middle layer of the coil, a portion of the chilled water enters the branch pipe and then merges into the branch pipe, then enters the flow regulating valve, and then enters the low-temperature return water network. In the middle layer of the coil, another portion of the chilled water enters the upper part of each coil, converges at the high-temperature return water inlet, and enters the high-temperature return water network.

[0083] In this embodiment, the functions of Embodiment 1 and Embodiment 2 are achieved through a multi-coil surface cooler, branch pipes, branch pipes, and flow regulating valves. Compared with other embodiments, the number of surface coolers in the dual-return water terminal air conditioner is reduced, making installation easier.

[0084] More preferably, the dual-return terminal air conditioner (100) also includes a check valve, which is disposed between the multi-layer surface cooler and the terminal secondary pump (150).

[0085] Example 3:

[0086] like Figure 5 As shown, the difference between Embodiment 3 and Embodiment 2 or Example 1 is that this embodiment also includes a pressure relief module 500 and a differential pressure sensor.

[0087] The pressure relief module 500 consists of pipes and a check valve. The data center dual return water cooling system adjusts the speed of the primary pump to make the pressure difference between the water supply network and the low-temperature return water network close to zero.

[0088] In this embodiment, the differential pressure sensor is installed on the water supply network and the low-temperature return network. The speed of the primary pump is adjusted by detecting the pressure difference between the supply and return networks near the one-way pressure relief module.

[0089] Specific control examples are as follows:

[0090] 1) The frequency of the primary pump in the chiller unit is dynamically adjusted by real-time detection of the pressure difference between the supply and return water pipes near the one-way pressure relief module, i.e., the pump speed is adjusted.

[0091] 1a) When the pressure of the water supply network 410 is greater than the pressure of the low temperature return water network 420 (pressure difference > 0 kPa), the frequency of the primary pump inverter is reduced, that is, the speed of the water pump is reduced.

[0092] 1b) When the pressure of the water supply network 410 is less than the pressure of the low temperature return water network 42 (pressure difference < 0 kPa), the frequency of the primary pump inverter is increased, that is, the speed of the water pump is increased.

[0093] In engineering practice, a pressure difference is considered close to zero when its absolute value is no greater than 5 kPa, 10 kPa, or 20 kPa. In engineering control, the pump speed is generally adjusted by regulating the pump's frequency.

[0094] This method allows for continuous water supply between the water supply network and the low-temperature return water network without requiring a large pressure difference. It enables both the primary and secondary pumps to operate at lower loads, resulting in high pump efficiency and energy savings compared to traditional high-pressure differential solutions.

[0095] Preferably, the data center dual-return water cooling system further includes a water storage device 600. The water storage device comprises a storage tank, an electric two-way regulating valve, a temperature sensor, and a controller. When the chiller loses power or malfunctions, the water storage device pumps return water from the low-temperature return water network and injects chilled water into the supply water network. In this embodiment, the preferred storage water temperature is 4-8℃, rather than the commonly used 10-12℃ storage temperature, which reduces the volume and floor space of the storage tank under the same storage requirements, thus reducing initial investment.

[0096] By installing a water storage device in the dual-return water cooling system of the data center, the reliability of the system is increased, so that the system can still work normally when the chiller is powered off or malfunctions.

[0097] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0098] The above embodiments merely illustrate preferred implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention should be determined by the appended claims.

Claims

1. A dual return water terminal air conditioner, characterized in that: comprising a shell (110), a return air inlet (121), an air outlet (122), a fan (160), a flow regulating valve containing a shunt device, a first surface cooler (131), a second surface cooler (132), a water inlet (171), a terminal secondary pump (150), a low-temperature return water outlet (172), a high-temperature return water outlet (173), a return air temperature sensor (181), a high-temperature return water temperature sensor (182), an air supply temperature sensor (183), and a controller; the shunt device is a three-way regulating device, the water inlet end of the shunt device is connected with the water outlet end of the first surface cooler (131), the first water outlet end of the shunt device is connected with the water inlet end of the second surface cooler (132), and the second water outlet end of the shunt device is connected with the low-temperature return water outlet (172); the return air inlet (121), the second surface cooler (132), the first surface cooler (131), the fan (160), and the air outlet (122) are sequentially arranged along the air flow direction of the dual return water terminal air conditioner (100); the return air temperature sensor (181) is arranged in the middle of the return air inlet (121) and is used for measuring the return air temperature of the dual return water terminal air conditioner (100); the high-temperature return water temperature sensor (182) is arranged between the water outlet end of the second surface cooler (132) and the high-temperature return water outlet (173) and is used for measuring the high-temperature chilled water temperature of the dual return water terminal air conditioner (100); and the air supply temperature sensor (183) is arranged in the middle of the air outlet (122) and is used for measuring the air supply temperature of the dual return water terminal air conditioner (100); the controller adjusts the flow of the high-temperature chilled water of the high-temperature return water outlet (173) by adjusting the flow of the flow regulating valve, so that the temperature of the high-temperature chilled water of the high-temperature return water outlet is higher than the outdoor air wet-bulb temperature and close to the return air temperature of the dual return water terminal air conditioner; and the controller controls the rotating speed of the fan (160) so that the return air temperature of the dual return water terminal air conditioner (100) reaches a set value; the terminal secondary pump (150) is arranged between the first surface cooler (131) and the water inlet (171); and the controller adjusts the water inlet flow of the dual return water terminal air conditioner by controlling the rotating speed of the terminal secondary pump (150), so that the air supply temperature of the dual return water terminal air conditioner (100) reaches a set value. 2.The dual return water terminal air conditioner according to claim 1, characterized in that: the shunt device is an electric three-way shunt regulating valve (141). 3.The dual return water terminal air conditioner according to claim 1, characterized in that: the shunt device is composed of a shunt three-way (1421) and an electric two-way regulating valve (1422), and the electric two-way regulating valve (1422) is connected with the water outlet connector of the shunt three-way (1421). 4.A dual return water terminal air conditioner, characterized in that: ​ ​ ​ ​ ​ ​ ​ ​ The double backwater terminal air conditioner (100) comprises a shell (110), a return air inlet (121), an air supply outlet (122), a fan (160), a shunt device comprising a flow regulating valve and a plurality of shunt branch pipes, a multi-layer surface cooler connected with the shunt branch pipes, a water inlet (171), a terminal secondary pump (150), a low-temperature return water outlet (172), a high-temperature return water outlet (173), a return air temperature sensor (181), a high-temperature return water temperature sensor (182), an air supply temperature sensor (183), and a controller. The multi-layer surface cooler is composed of a plurality of coils, and a shunt branch pipe is arranged at the middle of each coil by means of a Y-shaped tee joint; all the shunt branch pipes are connected with a shunt pipe; the multi-layer surface cooler is divided into a lower half (133a) and an upper half (133b) at the shunt branch pipes along the direction of the coils. The shunt branch pipes shunt a part of chilled water from the coils of the surface cooler, and the chilled water shunted by the shunt branch pipes flows into the shunt pipe and then flows out through the flow regulating valve. The return air inlet (121), the upper half (133b) of the multi-layer surface cooler, the lower half (133a) of the multi-layer surface cooler, the fan (160), and the air supply outlet (122) are sequentially arranged along the air flow direction of the double backwater terminal air conditioner (100). The return air temperature sensor (181) is arranged at the middle of the return air inlet (121) and is used to measure the return air temperature of the double backwater terminal air conditioner (100); the high-temperature return water temperature sensor (182) is arranged between the water outlet of the upper half (133b) of the multi-layer surface cooler and the high-temperature return water outlet (173) and is used to measure the high-temperature chilled water temperature of the double backwater terminal air conditioner (100); and the air supply temperature sensor (183) is arranged at the middle of the air supply outlet (122) and is used to measure the air supply temperature of the double backwater terminal air conditioner (100). The controller adjusts the flow of the high-temperature chilled water of the high-temperature return water outlet (173) by adjusting the flow of the flow regulating valve, so that the temperature of the high-temperature chilled water of the high-temperature return water outlet is higher than the outdoor air wet-bulb temperature and close to the return air temperature of the double backwater terminal air conditioner; and the controller controls the rotating speed of the fan (160) so that the return air temperature of the double backwater terminal air conditioner (100) reaches a set value. The terminal secondary pump (150) is arranged between the lower half (133a) of the multi-layer surface cooler and the water inlet (171), and the controller adjusts the water inflow of the double backwater terminal air conditioner by controlling the rotating speed of the terminal secondary pump (150) so that the air supply temperature of the double backwater terminal air conditioner (100) reaches a set value.

5. A data center double backwater cooling system, characterized in that: The system comprises several double water return terminal air conditioners (100) according to any one of claims 1-4, several cooling towers (200), several cold water main machines (300), several primary pumps (151), a water supply network (410), a low temperature water return network (420), and a high temperature water return network (430); The water inlet (171) of any one of the double water return terminal air conditioners (100) is connected to the water supply network (410); the low temperature water return outlet (172) of any one of the double water return terminal air conditioners (100) is connected to the water inlet of the low temperature water return network (420); the high temperature water return outlet (173) of any one of the double water return terminal air conditioners (100) is connected to the water inlet of the high temperature water return network (430); The water inlet of any one of the cooling towers (200) is connected to the high temperature water return network (430); the water outlet of any one of the cooling towers (200) is connected to the low temperature water return network (420); The water inlet of any one of the primary pumps (151) is connected to the low temperature water return network (420); the water outlet of any one of the primary pumps (151) is connected to the evaporator of the cold water main machine (300); the water outlet of any one of the cold water main machines (300) is connected to the water supply network (410); The water outlet temperature of the cooling tower (200) is lower than the maximum water return temperature that the cold water main machine (300) can withstand; when the water outlet temperature of the cooling tower (200) is higher than the maximum water outlet temperature that the cold water main machine (300) can withstand, the shunt device is adjusted so that the water flow of the high temperature water return outlet is zero.

6. The data center double water return cooling system according to claim 5, wherein: The cooling tower (200) is a closed cooling tower.

7. The data center double water return cooling system according to claim 6, wherein: The data center double water return cooling system further comprises a pressure relief module and a differential pressure sensor; the pressure relief module is composed of a pipe and a check valve; the pressure relief module is arranged between the water supply network and the low temperature water return network; by adjusting the rotation speed of the primary pump, the pressure difference between the water supply network and the low temperature water return network is close to zero.

8. The data center double water return cooling system according to claim 7, wherein: The data center double water return cooling system further comprises a water storage device; the water storage device comprises a storage tank, an electric two-way regulating valve, a temperature sensor, and a controller; when the cold water main machine is powered off or fails, the water storage device pumps water from the low temperature water return network and injects cold water into the water supply network.

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