Air conditioning unit and anti-freezing control method and pre-heat exchange control method thereof

Abstract

The application discloses an air conditioning unit and a freeze-proof control method and a pre-heat exchange control method thereof. The air conditioning unit comprises a cold source host and a freeze-proof system. The circulating loop of at least one side of the freezing side and the cooling side of the cold source host is provided with the freeze-proof system. The freeze-proof system comprises a storage device for storing different media. The storage device is provided with a pipeline assembly connected to the circulating loop. The storage device supplements or recovers the media to the circulating loop through the pipeline assembly. The application ensures the operation energy efficiency of the air conditioning unit by replacing the heat exchange medium of the cold source host. The comprehensive energy efficiency of the air conditioning unit is improved by designing a media exchanger for pre-cooling or pre-heating.

Description

Technical Field

[0001] This invention relates to the field of air conditioning unit technology, and in particular to air conditioning units and their antifreeze control methods and preheat exchange control methods. Background Technology

[0002] In data centers located in cold or frigid regions, systems with high freezing points of heat exchange media are prone to freezing due to low outdoor temperatures in winter. This is especially true for air conditioning units that require shutdown during intermittent operation, necessitating appropriate antifreeze measures. Two common antifreeze methods exist: the first utilizes electric heating, and the second involves mixing a certain concentration of refrigerant into the air conditioning unit's circulation loop as an antifreeze. From an economic and efficiency perspective, the second method is generally preferred.

[0003] Taking ethylene glycol solution as a refrigerant as an example, the air conditioning unit operates at low efficiency in winter due to its low specific heat and high viscosity. However, in other seasons, the air conditioning unit does not require antifreeze and can use heat exchange media with low viscosity, such as water, to improve its operating efficiency. But ethylene glycol solution is expensive, and simple discharge and treatment costs are high. This makes it difficult for the heat exchange media in the air conditioning unit to meet the operating needs of different seasons.

[0004] Therefore, how to design air conditioning units that can flexibly match the heat exchange medium requirements under different operating conditions is a technical problem that the industry urgently needs to solve. Summary of the Invention

[0005] To address the issues of low energy efficiency of the chiller unit and high energy consumption of the water pump when using ethylene glycol solution as a refrigerant for freeze protection in existing air conditioning units, this invention proposes an air conditioning unit and its freeze protection control method and pre-heat exchange control method. By changing the heat exchange medium of the chiller unit, the operating energy efficiency of the air conditioning unit is guaranteed.

[0006] The technical solution adopted in this invention is to design an air conditioning unit, including: a cold source host and an antifreeze system, wherein the antifreeze system is configured in the circulation loop of at least one side of the cold source host, the refrigeration side and the cooling side; the antifreeze system includes: a storage device for storing different media, the storage device is provided with a pipeline assembly connected to the circulation loop, and the storage device replenishes or recovers media to the circulation loop through the pipeline assembly.

[0007] Furthermore, the storage device includes a first media tank for storing antifreeze and a second media tank for storing water; The first medium tank is equipped with a concentration tank, and a liquid delivery channel with controllable on / off state is provided between the concentration tank and the first medium tank. The first medium tank and the concentration tank are each equipped with a separate recovery pipeline, and the recovery pipelines of the first medium tank and the concentration tank are connected to the water supply pipe of the cold source host. Both the second medium tank and the first medium tank are individually equipped with a replenishment line, which is connected to the circulation loop.

[0008] Furthermore, the air conditioning unit also includes: a medium heat exchanger and a fan for blowing airflow to the medium heat exchanger, wherein the main heat exchange tube of the medium heat exchanger is connected in series in the circulation loop; each of the replenishment pipelines is connected to the main heat exchange tube through a central pipeline, wherein a medium replacement pump for controlling the flow rate of the medium is installed on the central pipeline, and the medium replenished by the central pipeline is sent to the chiller unit through the main heat exchange tube.

[0009] Furthermore, the centralized pipeline includes a first centralized pipeline section and a second centralized pipeline section connected in series. The first centralized pipeline section is used to connect each of the replenishment pipelines, and the medium replacement pump is installed on the first centralized pipeline section. The second centralized pipeline section is used to connect the main heat exchange tube. The second medium tank is equipped with a return liquid pipeline connected to the first centralized pipe section. When the second centralized pipe section is shut off and the replenishment liquid pipeline of the second medium tank and the return liquid pipeline are connected, the replenishment liquid pipeline of the second medium tank connects with the return liquid pipeline to form a secondary heat exchange branch that exchanges heat with the main heat exchange tube.

[0010] Furthermore, the second medium tank is also equipped with a return pipeline, which is connected between the first centralized pipeline section and the return pipeline of the second medium tank. By switching the on / off state of the return pipeline, the medium is controlled to flow back to the first centralized pipeline section or be sent back to the second medium tank.

[0011] Furthermore, each pipe in the piping assembly is equipped with a valve to control its on / off state.

[0012] This invention also proposes an anti-freeze control method for air conditioning units, which is applied to the aforementioned air conditioning units. The anti-freeze control method includes: Obtain the operating status of the air conditioning unit; The pipeline assembly is controlled to replace the medium in the circulation loop according to the operating conditions.

[0013] Furthermore, the antifreeze system includes a first media tank for storing antifreeze and a second media tank for storing water; When operating in cooling mode during summer, the piping assembly is controlled to recover the antifreeze in the circulation loop to the first medium tank or the concentration tank, and the second medium tank is opened to replenish water into the circulation loop; And / or when operating in refrigeration mode during winter or transitional seasons, control the piping assembly to recover water in the circulation loop to the first medium tank or concentration tank, and open the first medium tank and / or the second medium tank to replenish the circulation loop with antifreeze of different concentrations.

[0014] In some embodiments, controlling the piping assembly to recover antifreeze from the circulation loop to a first medium tank or concentration tank includes: The concentrations of antifreeze C1 delivered by the cold source host and antifreeze C3 in the concentration tank are detected, and the magnitudes of antifreeze concentration C1, target storage concentration C0, and concentration deviation value ∆C0 are compared. When C1≤C0-∆C0 or C1>C0+∆C0, and the set time is met continuously, the antifreeze sent by the cold source host is recovered into the concentration tank until the concentration of antifreeze in the concentration tank is C0-∆C0≤C3≤C0+∆C0, and then the antifreeze in the concentration tank is sent to the first medium tank. And / or when C0-∆C0≤C1≤C0+∆C0, and the set time is met continuously, the antifreeze sent by the cold source host is recovered into the first medium tank.

[0015] Furthermore, opening the first media tank and / or the second media tank to replenish the circulation loop with antifreeze of different concentrations includes: The concentration of antifreeze C1 delivered by the cold source unit and the outdoor ambient temperature T2 are detected. The target antifreeze concentration C2 is calculated based on the outdoor ambient temperature T2, and the antifreeze concentration C1 is controlled within the allowable deviation range of the target antifreeze concentration C2. Compare the antifreeze concentration C1 with the target antifreeze concentration C2 and the concentration deviation value ∆C0; When C1 > C2 + ∆C0 and the set time is met continuously, stop adding antifreeze to the circulation loop, add water to the circulation loop, and gradually increase the water replenishment rate; When C2-∆C0≤C1≤C2+∆C0 and the set time is continuously met, the replenishment of antifreeze and water to the circulation loop is stopped. When C1≤C2-∆C0 and the set time is met continuously, the replenishment of antifreeze and water to the circulation loop is stopped, and the pipeline assembly is controlled to recover the antifreeze in the circulation loop to the first medium tank or concentration tank.

[0016] Furthermore, the antifreeze control method also includes: The return water pipe pressure P1 of the chiller unit is detected, and the magnitude of the return water pipe pressure P1 is compared with the target pressure value P10 and the pressure deviation value ∆P1. When P10+∆P1≥P1≥P10-∆P1 and the set time is continuously met, the medium in the circulation loop is full, and the replenishment of medium into the circulation loop stops.

[0017] This invention also proposes a pre-heat exchange control method for air conditioning units, wherein the pre-heat exchange control method is applied to the aforementioned air conditioning units, and the pre-heat exchange control method includes: The antifreeze system is installed on the freezing side and / or cooling side of the cold source unit; The medium heat exchanger is controlled to preheat or precool according to the installation location of the antifreeze system.

[0018] Furthermore, controlling the preheating or precooling of the medium heat exchanger according to the installation location of the antifreeze system includes: When the antifreeze system is installed on the cooling side of the cold source host, the actual inlet air temperature T6 of the fan is detected, and the actual inlet air temperature T6 is compared with the target inlet air temperature T60 and the inlet air temperature deviation value ∆T60. If T6 < T60 - ∆T6, the cold source host is turned off, the fan and the auxiliary heat exchange branch are turned on, and the medium heat exchanger is used to pre-cool the medium flowing through the main heat exchange tube. And / or when the antifreeze system is installed on the refrigeration side of the cold source host, determine whether the air conditioning unit has entered the pre-cooling mode. If so, turn on the fan and the auxiliary heat exchange branch, and use the medium heat exchanger to preheat the medium flowing through the main heat exchange tube.

[0019] Furthermore, precooling the medium flowing through the main heat exchanger using a medium heat exchanger includes: The temperature of the return water pipe T5 and the water temperature T8 of the return liquid pipe of the cold source unit are detected. When T5 > T50 + ∆T5 and the set time is met continuously, the frequency of the fan is gradually increased. If the frequency of the fan reaches the set upper limit value and is still in T5 > T50 + ∆T5, the auxiliary heat exchange branch is connected and the water replenishment rate is gradually increased. When T5 < T50 - ∆T5 and the set time is met continuously, the frequency of the fan is gradually reduced. If the frequency of the fan is still within T5 < T50 - ∆T5 when it reaches the set lower limit, the medium flow velocity of the main heat exchange tube is reduced. When T50+∆T5≥T5≥T50-∆T5 and T80+∆T8≥T8≥T80-∆T8, the medium flow velocity of the main heat exchange tube, the medium flow velocity of the secondary heat exchange branch, and the frequency of the fan remain unchanged. When T8≥T80+∆T8 and the set time is met continuously, the auxiliary heat exchange branch and the return pipeline are connected to block the second medium from being sent to the second medium tank. The frequency of the fan is gradually increased until T80+∆T8≥T8≥T80-∆T8. Then the return pipeline is disconnected and the second medium is sent back to the second medium tank. Where T50 is the target inlet temperature, ∆T5 is the inlet temperature deviation, T80 is the target return water temperature, and ∆T8 is the return water temperature deviation.

[0020] Furthermore, when T5 < T50 - ∆T5 and the set time is met continuously, and T8 ≥ T80 + ∆T8 and the set time is met continuously, the frequency of the fan is controlled according to the condition that T8 ≥ T80 + ∆T8 and the set time is met continuously.

[0021] Furthermore, preheating the medium flowing through the main heat exchanger using a medium heat exchanger includes: The actual inlet air temperature T6, the actual outlet air temperature T7, and the water temperature T8 of the return liquid pipeline of the fan are detected. When T6 > T60 + ∆T6 and the set time is met continuously, the medium flow velocity of the main heat exchange tube and the secondary heat exchange branch is increased until T70 + ∆T7 ≥ T7 ≥ T70 - ∆T7, or the medium flow velocity reaches the corresponding set upper limit value but is still at T7 ≥ T70 + ∆T7, then the chilled water supply temperature is reduced. When T6 < T60 - ∆T6 and the set time is met continuously, the medium flow velocity of the main heat exchange tube and the secondary heat exchange branch is reduced until T70 + ∆T7 ≥ T7 ≥ T70 - ∆T7, or the medium flow velocity reaches the corresponding set lower limit value but is still at T70 - ∆T7 ≥ T7, thereby increasing the chilled water supply temperature. When T70+∆T7≥T7≥T70-∆T7, the medium flow velocity and chilled water supply temperature of the secondary heat exchange branch remain unchanged; When T8≥T80+∆T8 and the set time is met continuously, the auxiliary heat exchange branch and the return pipeline are connected, the second medium is blocked from being sent back to the second medium tank, and the medium flow velocity of the main heat exchange tube is gradually increased until T80+∆T8≥T8≥T80-∆T8, the return pipeline is disconnected, and the second medium is sent back to the second medium tank. When T70+∆T7≥T7≥T70-∆T7 and T80+∆T8≥T8≥T80-∆T8, the medium flow velocity of the main heat exchange tube, the medium flow velocity of the secondary heat exchange branch, and the chilled water supply temperature all remain unchanged. Wherein, T60 is the target inlet air temperature, ∆T60 is the inlet air temperature deviation, T70 is the target outlet air temperature, ∆T70 is the outlet air temperature deviation, T80 is the target return water temperature, and ∆T8 is the return water temperature deviation.

[0022] Furthermore, when T6 < T60 - ∆T6 and the set time is continuously met, and T8 ≥ T80 + ∆T8 and the set time is continuously met, the medium flow velocity of the main heat exchanger tube is controlled according to the condition that T8 ≥ T80 + ∆T8 and the set time is continuously met.

[0023] Compared with the prior art, the present invention has the following beneficial effects: 1. Overcome the incompatibility of antifreeze requirements under different operating conditions in winter and summer by storing different media in the storage device and using pipeline components to replace the heat exchange medium in the circulation loop, thus ensuring the operating efficiency of the air conditioning unit. 2. Design corresponding antifreeze modes for different seasons. When operating in cooling mode in summer, replace the medium in the circulation loop with water, and when operating in cooling mode in other seasons, replace the medium in the circulation loop with antifreeze to simplify the year-round control logic of the air conditioning unit. 3. Design a medium heat exchanger for pre-cooling or preheating to improve the overall energy efficiency of the air conditioning unit; 4. The antifreeze system is installed on the cooling side and can use the medium heat exchanger to perform multi-stage treatment of the cooling water, making full use of natural cooling, further reducing the cooling temperature to reduce the condensing temperature of the cold source unit, thereby improving the overall energy efficiency of the air conditioning unit. 5. The antifreeze system is installed on the chilled side, which can make multi-stage use of chilled water, further increase the chilled temperature to increase the evaporation temperature, thereby improving the overall energy efficiency of the air conditioning unit. At the same time, the chilled water return temperature is used to maintain the temperature balance of the water replenishment in the second medium tank and avoid stratification. Attached Figure Description

[0024] The present invention will now be described in detail with reference to the embodiments and accompanying drawings, wherein: Figure 1 This is a schematic diagram showing the connection of the antifreeze system of the present invention installed on the freezing side / cooling side of the cold source host; Figure 2 This is a schematic diagram of the internal connections of the medium heat exchanger of the present invention; Figure label: 1. Cooling tower / terminal unit; 2. First water pump; 3. Cold source unit; 4. Second water pump; 5. Concentrator; 6. First medium tank; 7. Second medium tank; 8. Medium replacement pump; 9. Medium heat exchanger; 91. Main heat exchange tube; 10. Fan; 101. Concentration and recovery valve; 102. Straight-through recovery valve; 103. Storage valve; 104. First medium filling valve; 105. Second medium filling valve; 106. Return valve; 107. Circulation valve; 108. Replenishment valve; 109. Loop valve; 110. Water supply valve; 111. First centralized pipeline section; 112. Second centralized pipeline section; 113. First return pipeline section; 114. Second return pipeline section; 115. Return pipeline; 201. Outlet concentration detector; 202. Outdoor temperature sensor; 203. Concentrator tank concentration detector; 204. Return water pressure sensor; 205. Return water temperature sensor; 206. Inlet air temperature sensor; 207. Outlet air temperature sensor; 208. Return liquid temperature sensor. Detailed Implementation

[0025] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0026] The air conditioning unit and its antifreeze control method and pre-heat exchange control method proposed in this invention achieve the goal of meeting the high-efficiency operation requirements of the cold source host and the air conditioning unit while meeting the antifreeze requirements by controlling the replacement of the heat exchange medium inside the circulation loop under different outdoor temperature conditions, thus avoiding the freezing of the medium in the low-temperature environment and preventing the air conditioning unit from being unable to continue cooling.

[0027] like Figure 1 As shown, specifically, the air conditioning unit of the present invention includes a cold source unit 3 and an antifreeze system.

[0028] The chiller unit 3 is equipped with water pumps on both the cooling and freezing sides, namely the first water pump 2 and the second water pump 4, which are installed on the return water side of their respective circulation loops. At least one of the circulation loops on the freezing and cooling sides of the chiller unit 3 is equipped with an antifreeze system, that is, the antifreeze system can be set in either the cooling side circulation loop or the freezing side circulation loop. The circulation loop mentioned below refers to the circulation loop on the side where the antifreeze system is located.

[0029] When the antifreeze system is set on the freezing side Figure 1 The right side of the image shows the refrigeration side of the cold source unit 3. Figure 1 The left-hand side marker 1 indicates a cooling tower; when the antifreeze system is installed on the cooling side, Figure 1 The right side of the image shows the cooling side of the cold source unit 3. Figure 1 The left-hand marker 1 in the text indicates the end.

[0030] The antifreeze system includes a storage device for storing different media. The storage device is equipped with a piping assembly connected to a circulation loop, through which media are replenished to or recovered from the circulation loop. This invention overcomes the incompatibility issues arising from the different antifreeze requirements under different operating conditions in winter and summer. By storing different media in the storage device and using the piping assembly to replace the heat exchange medium in the circulation loop, the energy efficiency of the air conditioning unit is ensured.

[0031] Taking a data center air conditioning unit, with ethylene glycol solution as the first medium and water as the second medium, and considering the stable load characteristics of the data center, in summer, the ethylene glycol solution in the circulation loop is recovered into the storage device through the piping assembly, and water is injected into the circulation loop to improve the operating efficiency of the chiller unit 3 and reduce the operating energy consumption of the water pump in the circulation loop. In winter or during transitional seasons, the water in the circulation loop is recovered into the storage device through the piping assembly, and ethylene glycol solution is injected into the circulation loop to improve the antifreeze level of the air conditioning unit.

[0032] like Figure 1 As shown, the storage device includes a first medium tank 6 for storing antifreeze and a second medium tank 7 for storing water. The first medium tank 6 is equipped with a concentration tank 5. A liquid delivery channel with controllable on / off state is provided between the concentration tank 5 and the first medium tank 6. The liquid delivery channel is equipped with a storage valve 103 to control its on / off state. In a preferred embodiment, the concentration tank 5 is placed on top of the first medium tank 6. When the storage valve 103 is opened, the first medium in the concentration tank 5 can flow into the first medium tank 6 by gravity.

[0033] Both the first medium tank 6 and the concentration tank 5 are equipped with separate recovery pipelines, and these recovery pipelines are connected to the water supply pipe of the chiller unit 3. When recovering medium from the circulation loop, the recovery pipeline of the first medium tank 6 or the concentration tank 5 is connected, and the water supply valve 110 on the water supply side of the circulation loop is disconnected. The inlet of the recovery pipeline is located upstream of the water supply valve 110, allowing all the medium flowing out of the chiller unit 3 to enter the first medium tank 6 or the concentration tank 5, thus achieving medium recovery. Both the first medium tank 6 and the second medium tank 7 are equipped with separate replenishment pipelines, which are connected to the circulation loop. When replenishing medium to the circulation loop, the replenishment pipelines of the first medium tank 6 and / or the second medium tank 7 are connected, allowing the medium flowing out of the storage device to enter the circulation loop, thus achieving medium replacement in the circulation loop.

[0034] It should be understood that the centralized pipeline, replenishment pipeline, and recovery pipeline mentioned above are all pipeline components.

[0035] like Figure 1 , 2As shown, in some embodiments of the present invention, the air conditioning unit further includes a medium heat exchanger 9 and a fan 10. The fan 10 is installed on one side of the medium heat exchanger 9, and its function is to blow airflow into the medium heat exchanger 9 to exchange heat between the air and the medium heat exchanger 9. The main heat exchange tube 91 of the medium heat exchanger 9 is connected in series in the circulation loop. Each replenishment pipe is connected to the main heat exchange tube 91 through a centralized pipe. A medium replacement pump 8 for controlling the flow rate of the medium is installed on the centralized pipe. The medium replenished by the centralized pipe is sent to the chiller 3 through the main heat exchange tube 91, that is, the main heat exchange tube 91 is installed on the return water side of the circulation loop. The present invention designs the medium heat exchanger 9 in the circulation loop for pre-cooling or pre-heating, thereby improving the overall energy efficiency of the air conditioning unit.

[0036] Based on the above embodiments, the centralized pipeline includes a first centralized pipeline section 111 and a second centralized pipeline section 112 connected in series. The first centralized pipeline section 111 is used to connect each replenishment pipeline, and the medium replacement pump 8 is installed on the first centralized pipeline section 111. The second centralized pipeline section 112 is used to connect the main heat exchange tube 91. The second medium tank 7 is equipped with a return pipeline connected to the first centralized pipeline section 111. When the second centralized pipeline section 112 is turned off and the replenishment pipeline and return pipeline of the second medium tank 7 are connected, the second medium flowing out of the second medium tank 7 is sent to the first centralized pipeline section 111 through the replenishment pipeline, then flows from the first centralized pipeline section 111 to the return pipeline, and finally is sent back to the second medium tank 7. The second medium flowing through the medium heat exchanger 9 exchanges heat with the medium in the main heat exchange tube 91, which essentially makes the replenishment pipeline of the second medium tank 7 connected to the return pipeline to form a secondary heat exchange branch that exchanges heat with the main heat exchange tube 91.

[0037] The advantage of this design is that the medium heat exchanger can not only use air to exchange heat with the medium in the main heat exchange tube, but also use the medium in the second medium tank to exchange heat with the medium in the main heat exchange tube, thus improving heat exchange efficiency.

[0038] Based on the above embodiments, the second medium tank 7 is also equipped with a return pipeline 115. The return pipeline includes a first return pipeline section 113 and a second return pipeline section 114 connected in series. The first return pipeline section 113 is used to connect to the first centralized pipeline section 111, and the second return pipeline section 114 is used to connect to the second medium tank 7. The return pipeline 115 is connected between the first centralized pipeline section 111 and the first return pipeline section 113. By switching the on / off state of the return pipeline 115, the medium is controlled to flow back to the first centralized pipeline section 111 or be sent back to the second medium tank 7. In other words, when the secondary heat exchange branch is open—that is, when the medium replacement pump 8 is working, the second centralized pipe section 112 is closed, the first return pipe section 113 is connected, and the replenishment pipe of the second medium tank 7 is connected—when the second return pipe section 114 is closed and the return pipe 115 is connected, the second medium flowing out of the second medium tank 7 is sent back to the first centralized pipe section 111 through the return pipe 115 to continue circulating. When the second return pipe section 114 is connected and the return pipe 115 is closed, the second medium flowing out of the second medium tank 7 is sent back to the second medium tank 7 through the second return pipe section 114.

[0039] The advantage of this design is that it allows for flexible adjustment of the heat exchange capacity of the medium heat exchanger, adapting to the heat exchange requirements of the air conditioning unit under different operating conditions and improving the overall energy efficiency of the air conditioning unit.

[0040] Specifically, each pipeline in the pipeline assembly is equipped with a valve to control its on / off state. The recovery pipeline of the first medium tank 6 is equipped with a straight-through recovery valve 102, the recovery pipeline of the concentration tank 5 is equipped with a concentration recovery valve 101, the replenishment pipeline of the first medium tank 6 is equipped with a first medium filling valve 104, the replenishment pipeline of the second medium tank 7 is equipped with a second medium filling valve 105, the second return pipeline section 114 is equipped with a return valve 106, the first return pipeline section 113 is equipped with a loop valve 109, the return pipeline 115 is equipped with a circulation valve 107, and the second centralized pipeline section 112 is equipped with a replenishment valve 108.

[0041] When the storage device replenishes the circulating loop with medium, the replenishment valve 108 is normally open, the circulating valve 107 and the loop valve 109 are normally closed, and the secondary heat exchange branch is not working. After the storage device has completed the medium replacement, the concentration recovery valve 101, the direct recovery valve 102 and the replenishment valve 108 are normally closed, and the secondary heat exchange branch can be selectively opened as needed.

[0042] This invention also proposes an anti-freeze control method for air conditioning units, which is applied to the aforementioned air conditioning units. The anti-freeze control method includes: Obtain the operating status of the air conditioning unit; The medium in the circulation loop is replaced according to the operating conditions of the control pipeline components.

[0043] The advantage of this design is that it can overcome the incompatibility of different antifreeze requirements under different operating conditions in winter and summer. Different media are stored in the storage device, and the heat exchange medium in the circulation loop is replaced by the pipeline assembly, so as to ensure the operating efficiency of the air conditioning unit.

[0044] like Figure 1 As shown, in some embodiments of the present invention, the antifreeze system includes a first medium tank 6 for storing antifreeze and a second medium tank 7 for storing water. When operating in cooling mode during summer, the control piping assembly recovers the antifreeze in the circulation loop to the first medium tank 6 or the concentration tank 5. After the recovery is completed, the replenishment pipeline of the second medium tank 7 is opened to replenish water into the circulation loop. And / or when operating in refrigeration mode during winter or transitional season, the control piping assembly recovers water in the circulation loop to the first medium tank 6 or the concentration tank 5. After recovery is completed, the replenishment piping of the first medium tank 6 and / or the second medium tank 7 is opened to replenish antifreeze of different concentrations into the circulation loop.

[0045] The advantage of this design is that it allows for different antifreeze modes to be designed for different seasons. When operating in cooling mode in summer, the medium in the circulation loop is replaced with water, and when operating in cooling mode in other seasons, the medium in the circulation loop is replaced with antifreeze, simplifying the year-round control logic of the air conditioning unit.

[0046] Specifically, in some embodiments of the present invention, the method by which the control pipeline assembly recovers the antifreeze in the circulation loop to the first medium tank or the concentration tank is as follows: The concentration of antifreeze C1 delivered by the cold source host and the concentration of antifreeze C3 in the concentration tank are detected, and the magnitude of the antifreeze concentration C1 is compared with the target storage concentration C0 and the concentration deviation value ∆C0. When C1≤C0-∆C0 or C1>C0+∆C0 and the set time is met continuously, it indicates that the concentration of the first medium recovered is too low or too high. It is necessary to adjust the concentration of the first medium using the concentration tank. Therefore, the antifreeze sent by the cold source host 3 is recovered into the concentration tank 5 until the concentration of the antifreeze in the concentration tank 5 is C0-∆C0≤C3≤C0+∆C0 - that is, the concentration of the first medium is appropriate. Then, the storage valve 103 is opened to send the antifreeze in the concentration tank 5 into the first medium tank 6. And / or when C0-∆C0≤C1≤C0+∆C0 and the set time is met continuously, it indicates that the concentration of the first medium to be recovered is appropriate, and the antifreeze sent by the cold source host 3 is recovered into the first medium tank 6.

[0047] The advantage of this design is that it keeps the concentration of the first medium stored in the first medium tank 6 at a moderate level near the target storage concentration C0, and it can also realize the complete recovery of the first medium in the circulation loop for reuse when needed, thereby reducing the system operating cost.

[0048] It should be noted that the preferred solution is to adjust the target storage concentration C0 based on the outdoor ambient temperature T2. In practical applications, there are at least two feasible methods: The first method is to divide the range of outdoor ambient temperature T2 into intervals, design a corresponding target storage concentration C0 for each temperature interval, and when the control pipeline assembly recovers the antifreeze in the circulation loop to the first medium tank or the concentration tank, the outdoor ambient temperature T2 is detected, and the corresponding target storage concentration C0 is obtained based on the temperature interval in which the outdoor ambient temperature T2 falls. This target storage concentration C0 is used to determine whether the antifreeze is recovered to the first medium tank or the concentration tank. The second method is to divide the range of target antifreeze concentration C2 into intervals, design a corresponding target storage concentration C0 for each concentration interval, and when the control pipeline assembly recovers the antifreeze in the circulation loop to the first medium tank or the concentration tank, the outdoor ambient temperature T2 is detected, the freezing point temperature is calculated based on the outdoor ambient temperature T2, and then the corresponding target antifreeze concentration C2 is calculated from the freezing point temperature. The corresponding target storage concentration C0 is then obtained based on the concentration interval in which the target antifreeze concentration C2 falls. This target storage concentration C0 is used to determine whether the antifreeze is recovered to the first medium tank or the concentration tank.

[0049] In some embodiments of the present invention, opening the first medium tank 6 and / or the second medium tank 7 to replenish the circulation loop with antifreeze of different concentrations includes: The concentration of antifreeze C1 delivered by the cold source host 3 and the outdoor ambient temperature T2 are detected. The freezing point temperature is calculated based on the outdoor ambient temperature T2, and then the corresponding target antifreeze concentration C2 is calculated from the freezing point temperature. The medium replacement pump, the first medium filling valve 104, and the second medium filling valve 105 are adjusted to control the antifreeze concentration C1 within the allowable deviation range of the target antifreeze concentration C2. In this embodiment, the allowable deviation range is to control the antifreeze concentration C1 between C2-∆C0 and C2+∆C0. During the process of replenishing antifreeze, antifreeze is first added to the circulation loop, and the magnitude of the antifreeze concentration C1, the target antifreeze concentration C2, and the concentration deviation value ∆C0 are compared in real time. When C1 > C2 + ∆C0 and the set time is met continuously, it indicates that the antifreeze concentration is too high. Stop adding antifreeze to the circulation loop, that is, close the first medium filling valve 104 and open the second medium filling valve 105 to add water to the circulation loop and gradually increase the water replenishment rate - that is, increase the frequency of the medium replacement pump 8. During the process of increasing the water replenishment rate, the antifreeze concentration C1 gradually decreases. When C2-∆C0≤C1≤C2+∆C0 and the set time is met continuously, it indicates that the concentration of antifreeze added to the circulation loop is appropriate and has been continuously added for the set time. At this time, it is considered that the medium in the circulation loop is full, and the addition of antifreeze and water to the circulation loop is stopped. The first medium filling valve 104, the second medium filling valve 105 and the medium replacement pump 8 are closed, and the antifreeze system exits the antifreeze replenishment mode. When C1≤C2-∆C0 and the set time is met continuously, it indicates that the antifreeze concentration is too low and does not meet the current antifreeze requirements. Stop adding antifreeze and water to the circulation loop, and control the pipeline components to recover the antifreeze in the circulation loop to the first medium tank or concentration tank. After the antifreeze in the circulation loop is recovered, add antifreeze to the circulation loop again.

[0050] The advantage of this design is that it can replenish the system with an appropriate concentration of antifreeze according to the outdoor temperature, ensuring the antifreeze effect of the air conditioning unit while improving the operating energy efficiency of the chiller and reducing the operating energy consumption of the water pump in the circulation loop.

[0051] In some embodiments of the present invention, whether the medium is full can be determined by the return water pressure P1 of the chiller connected to the circulating unit in the circulation loop. The return water pressure P1 of the chiller is detected, and the magnitude of the return water pressure P1 is compared with the target pressure value P10 and the pressure deviation value ∆P1. When P10+∆P1≥P1≥P10-∆P1 and the set time is met continuously, the medium in the circulation loop is full, and the replenishment of medium into the circulation loop is stopped. That is, when the medium is full, the return water pressure P1 should be within the corresponding full pressure range.

[0052] It should be noted that, in the preferred embodiment, when operating in cooling mode during summer, the second medium tank is opened to replenish water into the circulation loop, and the target pressure value P10 is the corresponding set value. When operating in cooling mode during winter or transitional season, the target pressure value P10 is adjusted according to the target antifreeze concentration C2. The range of variation of the target antifreeze concentration C2 is divided into intervals, and a corresponding target pressure value P10 is designed for each concentration interval. When the first medium tank and / or the second medium tank are opened to replenish antifreeze of different concentrations into the circulation loop, the outdoor ambient temperature T2 is detected, the freezing point temperature is calculated based on the outdoor ambient temperature T2, and then the corresponding target antifreeze concentration C2 is calculated from the freezing point temperature. The corresponding target pressure value P10 is obtained according to the concentration interval in which the target antifreeze concentration C2 is located. This target pressure value P10 is used to determine whether the medium in the circulation loop is full.

[0053] In practical applications, the determination of whether the medium is full can be based on either the antifreeze concentration C1 or the return pipe pressure P1. If both conditions are met, a priority can be set, and the medium is considered full if the condition with the higher priority is satisfied. Additionally, the return pipe pressure P1 should be within the corresponding empty pressure range when medium recovery is complete.

[0054] like Figure 1 As shown, the present invention also proposes a pre-heat exchange control method for air conditioning units. This pre-heat exchange control method is applied to the aforementioned air conditioning units and includes: Ensure the antifreeze system is installed on the freezing side and / or cooling side of the cold source unit; The heat exchanger 9 is controlled to preheat or precool the medium according to the installation location of the antifreeze system.

[0055] The advantage of this design is that it utilizes the medium heat exchanger 9 for pre-cooling or preheating, thereby improving the overall energy efficiency of the air conditioning unit.

[0056] In some embodiments of the present invention, controlling the preheating or precooling of the medium heat exchanger 9 according to the installation location of the antifreeze system includes: When the antifreeze system is installed on the cooling side of the cold source host 3, the actual air inlet temperature T6 of the fan 10 is detected, and the actual air inlet temperature T6 is compared with the target air inlet temperature T60 and the air inlet temperature deviation value ∆T60. If T6 < T60 - ∆T6, the cold source host 3 is turned off, the fan 10 and the auxiliary heat exchange branch are turned on, and the medium heat exchanger 9 is used to pre-cool the medium flowing through the main heat exchange tube 91. And / or when the antifreeze system is installed on the refrigeration side of the cold source unit 3, determine whether the air conditioning unit has entered the pre-cooling mode. If so, turn on the fan 10 and the auxiliary heat exchange branch, and use the medium heat exchanger 9 to preheat the medium flowing through the main heat exchange tube 91. Entering the pre-cooling mode here can be caused by the air conditioning unit's control module receiving a pre-cooling command.

[0057] The antifreeze system, located on the cooling side, utilizes the medium heat exchanger 9 to perform multi-stage treatment of the cooling water, making full use of natural cooling to further reduce the cooling temperature and thus lower the condensing temperature of the chiller unit 3, thereby improving the overall energy efficiency of the air conditioning unit. The antifreeze system, located on the chilled side, utilizes the chilled water in multiple stages to further increase the chilling temperature and thus increase the evaporating temperature of the chiller unit 3, thereby improving the overall energy efficiency of the air conditioning unit. Simultaneously, it uses the chilled water return temperature to maintain a balanced temperature for the second medium tank makeup water, preventing stratification.

[0058] like Figure 1 As shown, specifically, when the antifreeze system is installed on the cooling side of the cold source unit 3, the pre-cooling of the medium flowing through the main heat exchanger 91 using the medium heat exchanger 9 includes: Detect the return water pipe temperature T5 and the return liquid pipe water temperature T8 of the chiller unit 3; When T5 > T50 + ∆T5 and the set time is met continuously, the frequency of the blower 10 is gradually increased. If the frequency of the blower 10 is still T5 > T50 + ∆T5 when it reaches the set upper limit, the water replenishment speed is gradually increased - that is, the frequency of the medium replacement pump 8 is increased. When T5 < T50 - ∆T5 and the set time is met continuously, the frequency of the fan 10 is gradually reduced. If the frequency of the fan 10 is still within T5 < T50 - ∆T5 when it reaches the set lower limit, the medium flow velocity of the main heat exchange tube 91 is reduced - that is, the frequency of the second water pump 4 is reduced. When T50+∆T5≥T5≥T50-∆T5 and T80+∆T8≥T8≥T80-∆T8, the medium flow velocity of the main heat exchange tube 91, the medium flow velocity of the secondary heat exchange branch, and the frequency of the fan 10 all remain unchanged, that is, the frequency of the second water pump 4, the frequency of the medium replacement pump 8, and the frequency of the fan 10 all remain unchanged. When T8≥T80+∆T8 and the set time is met continuously, the return pipe 115 is connected to block the second medium from being sent to the second medium tank—that is, the circulation valve 107 is opened and the return valve 106 is closed, and the frequency of the fan is gradually increased until T80+∆T8≥T8≥T80-∆T8, the return pipe 115 is disconnected, and the second medium is sent to the second medium tank—that is, the circulation valve 107 is closed and the return valve 106 is opened; Where T50 is the target inlet temperature, ∆T5 is the inlet temperature deviation, T80 is the target return water temperature, and ∆T8 is the return water temperature deviation.

[0059] The advantage of this design is that the fan 10 introduces fresh outdoor air to pre-cool the medium in the main heat exchange tube 91, and the second medium provided by the second medium tank 7 is used for supplemental cooling, thereby reducing the temperature of the medium sent from the main heat exchange tube 91 to the cooling side of the cold source unit and improving the operating efficiency of the air conditioning unit. At the same time, the fresh outdoor air is used to maintain the temperature balance of the water replenished in the second medium tank and avoid stratification.

[0060] It should be noted that when T5 < T50 - ∆T5 and the set time is met continuously, and T8 ≥ T80 + ∆T8 and the set time is met continuously, due to the conflict in the control strategy of the fan frequency, the frequency of the fan 10 is controlled according to the condition T8 ≥ T80 + ∆T8 and the set time is met continuously.

[0061] like Figure 1 As shown, specifically, when the antifreeze system is installed on the refrigeration side of the cold source unit 3, the preheating of the medium flowing through the main heat exchange tube 91 using the medium heat exchanger 9 includes: The actual inlet air temperature T6, the actual outlet air temperature T7, and the water temperature T8 of the return liquid pipeline of the fan 10 are measured. When T6 > T60 + ∆T6 and the set time is met continuously, the medium flow rate of the main heat exchange tube 91 and the auxiliary heat exchange branch is increased—that is, the frequency of the second water pump 4 and the frequency of the medium replacement pump 8 are increased, until T70 + ∆T7 ≥ T7 ≥ T70 - ∆T7, or when the medium flow rate reaches the corresponding set upper limit value and is still at T7 ≥ T70 + ∆T7, the cooling capacity of the cold source host 3 is increased and the chilled water supply temperature is reduced. When T6 < T60 - ∆T6 and the set time is met continuously, the medium flow velocity of the main heat exchange tube 91 and the auxiliary heat exchange branch is reduced—that is, the frequency of the second water pump 4 and the frequency of the medium replacement pump 8 are reduced, until T70 + ∆T7 ≥ T7 ≥ T70 - ∆T7, or the medium flow velocity is still within T70 - ∆T7 ≥ T7 when it reaches the corresponding set lower limit value, then the cooling capacity of the cold source host 3 is reduced and the chilled water supply temperature is increased; When T70+∆T7≥T7≥T70-∆T7, the medium flow velocity and chilled water supply temperature of the secondary heat exchange branch remain unchanged, that is, the frequency of the medium replacement pump 8 and the operating status of the chiller 3 remain unchanged. When T8≥T80+∆T8 and the set time is met continuously, the return pipe 115 is connected to block the second medium from being sent to the second medium tank—that is, the circulation valve 107 is opened and the return valve 106 is closed, and the medium flow rate of the main heat exchange tube is gradually increased—the frequency of the second water pump 4 is increased until T80+∆T8≥T8≥T80-∆T8, the return pipe 115 is disconnected, and the second medium is sent back to the second medium tank—the circulation valve 107 is closed and the return valve 106 is opened; When T70+∆T7≥T7≥T70-∆T7 and T80+∆T8≥T8≥T80-∆T8, the medium flow velocity of the main heat exchange tube 91, the medium flow velocity of the secondary heat exchange branch, and the chilled water supply temperature all remain unchanged, that is, the frequency of the second water pump 4, the frequency of the medium replacement pump 8, and the operating status of the chiller 3 all remain unchanged. Wherein, T60 is the target inlet air temperature, ∆T60 is the inlet air temperature deviation, T70 is the target outlet air temperature, ∆T70 is the outlet air temperature deviation, T80 is the target return water temperature, and ∆T8 is the return water temperature deviation.

[0062] The advantage of this design is that the indoor return air introduced by the fan 10 preheats the medium in the main heat exchange tube 91. The medium in the main heat exchange tube 91 and the second medium provided by the second medium tank 7 both cool the indoor return air to reduce the return air temperature and increase the temperature of the medium sent from the main heat exchange tube 91 to the refrigeration side of the cold source unit, thereby improving the operating efficiency of the air conditioning unit. At the same time, the medium in the main heat exchange tube 91 exchanges heat with the second medium in the auxiliary heat exchange branch to maintain the temperature balance of the water replenishment in the second medium tank and avoid stratification.

[0063] It should be noted that when T6 < T60 - ∆T6 and the set time is met continuously, and T8 ≥ T80 + ∆T8 and the set time is met continuously, due to the conflict in the control strategy of the second water pump frequency, the medium flow velocity of the main heat exchange tube 91 is controlled according to the condition T8 ≥ T80 + ∆T8 and the set time is met continuously.

[0064] The antifreeze concentration C1 mentioned above is detected by the outlet concentration detector 201, the outdoor ambient temperature T2 is detected by the outdoor temperature sensor 202, the antifreeze concentration C3 is detected by the concentration detector 203, the return water pipe pressure P1 is detected by the return water pressure sensor 204, the return water pipe temperature T5 is detected by the return water temperature sensor 205, the actual inlet air temperature T6 is detected by the inlet air temperature sensor 206, the actual outlet air temperature T7 is detected by the outlet air temperature sensor 207, and the water temperature T8 is detected by the return liquid temperature sensor 208.

[0065] Furthermore, the set times appearing in different judgment conditions above can be the same or different, and the value of the set time is designed according to actual needs, for example, a set time of 60 seconds. Similarly, the upper limit values ​​of the frequencies of different components are designed according to the corresponding performance parameters of the components, and the amplitude of the frequency change can be the same or different, and the value of the frequency change amplitude is designed according to actual needs, for example, the frequency change amplitude can be 1Hz. Likewise, the increase or decrease of the chilled water supply temperature can also be designed according to actual needs, for example, an increase or decrease of 0.5℃ each time.

[0066] The antifreeze control method and preheating control method proposed above are both executed by the control module of the air conditioning unit. The control module ensures the operating efficiency of the air conditioning unit by controlling the pipeline components to replace the heat exchange medium of the cold source host. It also improves the overall energy efficiency of the air conditioning unit by controlling components such as the fan 10 and the medium replacement pump 8 to precool or preheat the return water side of the circulation loop where the medium heat exchanger is located.

[0067] It should be noted that the terminology used above is for describing specific embodiments only and is not intended to limit the exemplary embodiments of the present invention. When the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. The order of execution of actions, steps, etc., in the apparatus and methods shown in the specification and drawings can be implemented in any order unless a specific order is expressly specified, and as long as the output of a previous process is not used in a subsequent process. Similar sequential terms used for ease of description do not imply that such an order must be followed.

[0068] Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. Air conditioning unit, including: A cold source host and an antifreeze system, wherein the antifreeze system is configured in a circulation loop on at least one side of the cold source host, on the freezing side and the cooling side; characterized in that the antifreeze system includes: a storage device for storing different media, the storage device being provided with a piping assembly connected to the circulation loop, the storage device replenishing media to or recovering media from the circulation loop through the piping assembly; The storage device includes a first medium tank for storing antifreeze and a second medium tank for storing water; The first medium tank is equipped with a concentration tank, and a liquid delivery channel with controllable on / off state is provided between the concentration tank and the first medium tank. The first medium tank and the concentration tank are each equipped with a separate recovery pipeline, and the recovery pipelines of the first medium tank and the concentration tank are connected to the water supply pipe of the cold source host. Both the second medium tank and the first medium tank are equipped with separate replenishment lines, which are connected to the circulation loop; The air conditioning unit further includes: a medium heat exchanger and a fan for blowing airflow to the medium heat exchanger, wherein the main heat exchange tube of the medium heat exchanger is connected in series in the circulation loop; each of the replenishment pipelines is connected to the main heat exchange tube through a central pipeline, wherein a medium replacement pump for controlling the flow rate of the medium is installed on the central pipeline, and the medium replenished by the central pipeline is sent to the chiller unit through the main heat exchange tube.

2. The air conditioning unit according to claim 1, characterized in that, The centralized pipeline includes a first centralized pipeline section and a second centralized pipeline section connected in series. The first centralized pipeline section is used to connect each of the replenishment pipelines, and the medium replacement pump is installed on the first centralized pipeline section. The second centralized pipeline section is used to connect the main heat exchange tube. The second medium tank is equipped with a return liquid pipeline connected to the first centralized pipe section. When the second centralized pipe section is shut off and the replenishment liquid pipeline of the second medium tank and the return liquid pipeline are connected, the replenishment liquid pipeline of the second medium tank connects with the return liquid pipeline to form a secondary heat exchange branch that exchanges heat with the main heat exchange tube.

3. The air conditioning unit according to claim 2, characterized in that, The second medium tank is also equipped with a return pipeline, which is connected between the first centralized pipeline section and the return pipeline of the second medium tank. By switching the on / off state of the return pipeline, the medium can be controlled to flow back to the first centralized pipeline section or be sent back to the second medium tank.

4. The air conditioning unit according to any one of claims 1 to 3, characterized in that, Each pipe in the piping assembly is equipped with a valve to control its on / off state.

5. A method for antifreeze control of an air conditioning unit, wherein the antifreeze control method is applied to the air conditioning unit according to any one of claims 1 to 4, characterized in that, The antifreeze control method includes: Obtain the operating status of the air conditioning unit; The pipeline assembly is controlled to replace the medium in the circulation loop according to the operating conditions.

6. The antifreeze control method according to claim 5, characterized in that, The antifreeze system includes a first medium tank for storing antifreeze and a second medium tank for storing water; When operating in cooling mode during summer, the piping assembly is controlled to recover the antifreeze in the circulation loop to the first medium tank or the concentration tank, and the second medium tank is opened to replenish water into the circulation loop; And / or when operating in refrigeration mode during winter or transitional seasons, control the piping assembly to recover water in the circulation loop to the first medium tank or concentration tank, and open the first medium tank and / or the second medium tank to replenish the circulation loop with antifreeze of different concentrations.

7. The antifreeze control method according to claim 6, characterized in that, Controlling the piping assembly to recover antifreeze from the circulation loop to the first medium tank or concentration tank includes: The concentrations of antifreeze C1 delivered by the cold source host and antifreeze C3 in the concentration tank are detected, and the magnitudes of antifreeze concentration C1, target storage concentration C0, and concentration deviation value ∆C0 are compared. When C1≤C0-∆C0 or C1>C0+∆C0, and the set time is met continuously, the antifreeze sent by the cold source host is recovered into the concentration tank until the concentration of antifreeze in the concentration tank is C0-∆C0≤C3≤C0+∆C0, and then the antifreeze in the concentration tank is sent to the first medium tank. When C0-∆C0≤C1≤C0+∆C0 and the set time is met continuously, the antifreeze sent by the cold source host is recovered into the first medium tank.

8. The antifreeze control method according to claim 6, characterized in that, Adding antifreeze of different concentrations to the circulation loop by opening the first media tank and / or the second media tank includes: The concentration of antifreeze C1 delivered by the cold source unit and the outdoor ambient temperature T2 are detected. The target antifreeze concentration C2 is calculated based on the outdoor ambient temperature T2, and the antifreeze concentration C1 is controlled within the allowable deviation range of the target antifreeze concentration C2. Compare the antifreeze concentration C1 with the target antifreeze concentration C2 and the concentration deviation value ∆C0; When C1 > C2 + ∆C0 and the set time is met continuously, stop adding antifreeze to the circulation loop, add water to the circulation loop, and gradually increase the water replenishment rate; When C2-∆C0≤C1≤C2+∆C0 and the set time is continuously met, the replenishment of antifreeze and water to the circulation loop is stopped. When C1≤C2-∆C0 and the set time is met continuously, the replenishment of antifreeze and water to the circulation loop is stopped, and the pipeline assembly is controlled to recover the antifreeze in the circulation loop to the first medium tank or concentration tank.

9. The antifreeze control method according to any one of claims 5 to 8, characterized in that, The antifreeze control method further includes: The return water pipe pressure P1 of the chiller unit is detected, and the magnitude of the return water pipe pressure P1 is compared with the target pressure value P10 and the pressure deviation value ∆P1. When P10+∆P1≥P1≥P10-∆P1 and the set time is continuously met, the medium in the circulation loop is full, and the replenishment of medium into the circulation loop stops.

10. A pre-heat exchange control method for an air conditioning unit, wherein the pre-heat exchange control method is applied to the air conditioning unit according to claim 3, characterized in that, The preheat exchange control method includes: The antifreeze system is installed on the freezing side and / or cooling side of the cold source unit; The medium heat exchanger is controlled to preheat or precool according to the installation location of the antifreeze system.

11. The pre-heat exchange control method according to claim 10, characterized in that, Controlling the preheating or precooling of the medium heat exchanger according to the installation location of the antifreeze system includes: When the antifreeze system is installed on the cooling side of the cold source host, the actual inlet air temperature T6 of the fan is detected, and the actual inlet air temperature T6 is compared with the target inlet air temperature T60 and the inlet air temperature deviation value ∆T60. If T6 < T60 - ∆T6, the cold source host is turned off, the fan and the auxiliary heat exchange branch are turned on, and the medium heat exchanger is used to pre-cool the medium flowing through the main heat exchange tube. And / or when the antifreeze system is installed on the refrigeration side of the cold source host, determine whether the air conditioning unit has entered the pre-cooling mode. If so, turn on the fan and the auxiliary heat exchange branch, and use the medium heat exchanger to preheat the medium flowing through the main heat exchange tube.

12. The pre-heat exchange control method according to claim 11, characterized in that, Precooling the medium flowing through the main heat exchanger using a medium heat exchanger includes: The temperature of the return water pipe T5 and the water temperature T8 of the return liquid pipe of the cold source unit are detected. When T5 > T50 + ∆T5 and the set time is met continuously, the frequency of the fan is gradually increased. If the frequency of the fan reaches the set upper limit value and is still in T5 > T50 + ∆T5, the auxiliary heat exchange branch is connected and the water replenishment rate is gradually increased. When T5 < T50 - ∆T5 and the set time is met continuously, the frequency of the fan is gradually reduced. If the frequency of the fan is still within T5 < T50 - ∆T5 when it reaches the set lower limit, the medium flow velocity of the main heat exchange tube is reduced. When T50+∆T5≥T5≥T50-∆T5 and T80+∆T8≥T8≥T80-∆T8, the medium flow velocity of the main heat exchange tube, the medium flow velocity of the secondary heat exchange branch, and the frequency of the fan remain unchanged. When T8≥T80+∆T8 and the set time is met continuously, the auxiliary heat exchange branch and the return pipeline are connected to block the second medium from being sent to the second medium tank. The frequency of the fan is gradually increased until T80+∆T8≥T8≥T80-∆T8. Then the return pipeline is disconnected and the second medium is sent back to the second medium tank. Where T50 is the target inlet temperature, ∆T5 is the inlet temperature deviation, T80 is the target return water temperature, and ∆T8 is the return water temperature deviation.

13. The pre-heat exchange control method according to claim 12, characterized in that, When T5 < T50 - ∆T5 and the set time is met continuously, and T8 ≥ T80 + ∆T8 and the set time is met continuously, the frequency of the fan is controlled according to the condition that T8 ≥ T80 + ∆T8 and the set time is met continuously.

14. The pre-heat exchange control method according to claim 11, characterized in that, Preheating the medium flowing through the main heat exchanger using a medium heat exchanger includes: The actual inlet air temperature T6, the actual outlet air temperature T7, and the water temperature T8 of the return liquid pipeline of the fan are detected. When T6 > T60 + ∆T6 and the set time is met continuously, the medium flow velocity of the main heat exchange tube and the secondary heat exchange branch is increased until T70 + ∆T7 ≥ T7 ≥ T70 - ∆T7, or the medium flow velocity reaches the corresponding set upper limit value but is still at T7 ≥ T70 + ∆T7, then the chilled water supply temperature is reduced. When T6 < T60 - ∆T6 and the set time is met continuously, the medium flow velocity of the main heat exchange tube and the secondary heat exchange branch is reduced until T70 + ∆T7 ≥ T7 ≥ T70 - ∆T7, or the medium flow velocity reaches the corresponding set lower limit value but is still at T70 - ∆T7 ≥ T7, thereby increasing the chilled water supply temperature. When T70+∆T7≥T7≥T70-∆T7, the medium flow velocity and chilled water supply temperature of the secondary heat exchange branch remain unchanged; When T8≥T80+∆T8 and the set time is met continuously, the return pipeline is connected to block the second medium from being sent to the second medium tank, and the medium flow rate of the main heat exchange tube is gradually increased until T80+∆T8≥T8≥T80-∆T8, then the return pipeline is disconnected and the second medium is sent back to the second medium tank. When T70+∆T7≥T7≥T70-∆T7 and T80+∆T8≥T8≥T80-∆T8, the medium flow velocity of the main heat exchange tube, the medium flow velocity of the secondary heat exchange branch, and the chilled water supply temperature all remain unchanged. Wherein, T60 is the target inlet air temperature, ∆T60 is the inlet air temperature deviation, T70 is the target outlet air temperature, ∆T70 is the outlet air temperature deviation, T80 is the target return water temperature, and ∆T8 is the return water temperature deviation.

15. The pre-heat exchange control method according to claim 14, characterized in that, When T6 < T60 - ∆T6 and the set time is met continuously, and T8 ≥ T80 + ∆T8 and the set time is met continuously, the medium flow velocity of the main heat exchanger tube is controlled according to the condition that T8 ≥ T80 + ∆T8 and the set time is met continuously.

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