Air conditioning system for recovering heat energy in a fluorine cooling mode

Abstract

This invention relates to the field of heat recovery technology, specifically to an air conditioning system that recovers heat energy in a refrigerant-cooled mode, comprising a first system, a second system, and a recovery system. Both the first and second systems include a compressor, a compression check valve, a refrigerant pump, a refrigerant-cooled check valve, a condenser, a three-way valve, and an evaporator. A blower is installed at the evaporator. The recovery system includes a heat exchanger and a proportional two-way valve. The heat exchanger includes a water supply channel and two heat exchange channels. Both the first and second systems include a refrigerant-cooled mode, a compression mode, and a recovery mode. This invention, by setting up the first and second systems, enables the entire air conditioning system to have multiple cooling modes. Both systems are equipped with a recovery mode, which bypasses the condenser through the three-way valve, allowing the refrigerant to absorb heat in the evaporator and then enter the heat exchange channel of the heat exchanger, thereby transferring heat to the water supply channel of the heat exchanger and recovering the heat generated by the air conditioning system.

Description

Technical Field

[0001] This invention relates to the field of heat recovery technology, and more specifically to an air conditioning system that recovers heat energy in a refrigerant-cooled mode. Background Technology

[0002] Optimizing the energy efficiency of air conditioning systems is a crucial issue in data centers and other high-energy-consuming facilities. Existing air conditioning systems have shortcomings in heat recovery and waste heat treatment, which affect the overall energy efficiency and operational stability of the system.

[0003] For air-to-air heat exchangers, during heat exchange, they cannot fully recover all the heat, resulting in some energy loss. Furthermore, in low-temperature environments, air-to-air heat exchangers are prone to freezing, leading to a decrease in heat exchange efficiency and even blockage of heat exchange channels, affecting the normal operation of the system.

[0004] For air-cooled heat exchangers, the failure to effectively utilize waste heat leads to energy waste. The impact of waste heat emissions on the surrounding environment cannot be ignored, as it may cause local temperature increases and affect the operation of other equipment.

[0005] To overcome the shortcomings of existing technologies and improve the annual energy efficiency of air conditioning systems, a preheating recovery air conditioning system is needed. This system fully utilizes natural cooling sources and intelligently selects the machine's operating mode based on different ambient temperatures, thereby achieving optimal operation and reducing the overall system's energy consumption. Summary of the Invention

[0006] The purpose of this invention is to address the aforementioned shortcomings in the prior art by providing an air conditioning system that recovers heat energy in a refrigerant-cooled mode.

[0007] The objective of this invention is achieved through the following technical solution: an air conditioning system for heat recovery in fluorine-cooled mode, comprising a first system, a second system, and a recovery system; both the first system and the second system include a compressor, a compression check valve, a fluorine pump, a fluorine-cooled check valve, a condenser, a three-way valve, and an evaporator; a blower is provided at the evaporator; and an exhaust fan is provided at the condenser.

[0008] The recovery system includes a heat exchanger and a proportional two-way valve; the heat exchanger includes a water supply channel and two heat exchange channels; the proportional two-way valve is connected to the water supply channel; a differential pressure switch is provided between the inlet and outlet of the water supply channel; the two heat exchange channels are respectively connected to the first system and the second system;

[0009] Both the first system and the second system include a fluorine cooling mode, a compression mode, and a recovery mode.

[0010] The present invention is further configured such that, in compression mode, the refrigeration flow path of both the first system and the second system is: compressor-three-way valve-condenser-refrigerant refrigerant check valve-evaporator-compressor;

[0011] In refrigerant cooling mode, the flow path of the refrigeration system in both the first and second systems is: refrigerant pump - evaporator - compressor check valve - three-way valve - condenser - refrigerant pump;

[0012] In recovery mode, the flow path of the refrigerant in both the first and second systems is: refrigerant pump - evaporator - compression check valve - three-way valve - heat exchange channel - refrigerant pump.

[0013] The present invention is further configured such that: the compressor and the compression check valve are connected in parallel; the refrigerant pump and the refrigerant cooling check valve are connected in parallel; one end of the compressor is connected to the inlet end of the three-way valve; one outlet end of the three-way valve is connected to one end of the condenser; the other end of the condenser is connected to one end of the refrigerant pump; the other outlet end of the three-way valve is connected to the other end of the condenser through a heat exchange channel; the other end of the refrigerant pump is connected to one end of the evaporator; and the other end of the evaporator is connected to the other end of the compressor.

[0014] The present invention is further configured such that a liquid storage tank is provided between the other end of the condenser and one end of the fluorine pump; an electronic expansion valve is provided between the other end of the fluorine pump and one end of the evaporator; a gas-liquid separator is provided between the other end of the evaporator and the other end of the compressor; and a branch connecting the compressor and the gas-liquid separator is connected in parallel to both ends of the compression check valve.

[0015] The evaporators of the first system and the second system are arranged in an overlapping manner; the evaporator of the second system is located between the evaporator of the first system and the blower.

[0016] The present invention is further configured to include the following steps:

[0017] Step S1: Check if the proportional two-way valve is open to the first opening degree. If yes, proceed to step S2; otherwise, the first system and the second system maintain the current mode.

[0018] Step S2: Check if the differential pressure switch is open. If yes, proceed to step S3; otherwise, the first system and the second system maintain the current mode.

[0019] Step S3: Check if the return water temperature at the inlet of the water supply channel is lower than the first return water temperature value. If yes, proceed to step A; otherwise, proceed to step S4.

[0020] Step A: Both the first and second systems enter recycling mode; then proceed to step B1;

[0021] Step S4: Detect whether the return water temperature at the inlet of the water supply channel is lower than the second return water temperature value. If the second return water temperature value is greater than the first return water temperature value, proceed to step C; otherwise, the first system and the second system maintain the current mode.

[0022] Step C: The first system maintains its current mode, while the second system enters recycling mode; then proceed to step D.

[0023] The present invention is further configured to include the following steps:

[0024] Step D: Detect the water supply temperature at the outlet of the water supply channel, the air supply temperature of the blower, and the opening degree of the proportional two-way valve; if the water supply temperature at the outlet of the water supply channel is less than the set water supply temperature in the first time, the air supply temperature of the blower is less than the first air supply temperature value in the second time, and the opening degree of the proportional two-way valve is less than the second opening degree, then proceed to step A; the second opening degree is less than the first opening degree.

[0025] Step D further includes: if the proportional two-way valve opens to the third opening degree and the air supply temperature of the blower is greater than the second air supply temperature value within the third time period, then proceed to step D1; the third opening degree is less than the first opening degree and greater than the second opening degree.

[0026] Step D1: Check if the outdoor temperature is lower than the outdoor temperature set value. If yes, proceed to step D11; otherwise, proceed to step D12.

[0027] Step D11: The first system maintains the current mode, the second system enters the refrigerant cooling mode, and then proceeds to step S1;

[0028] Step D12: The first system maintains the current mode, the second system enters the compression mode, and then proceeds to step S1.

[0029] The present invention is further configured to include the following steps:

[0030] Step B1: Check if the proportional two-way valve is open to the third degree. If yes, proceed to step B2; otherwise, the first and second systems remain in recovery mode.

[0031] Step B2: Check whether the air supply temperature of the blower is greater than the second air supply temperature value within the third time period. If yes, proceed to step B3; otherwise, the first system and the second system maintain the recycling mode.

[0032] Step B3: Check if the outdoor temperature is lower than the outdoor temperature setting. If yes, proceed to step B31; otherwise, proceed to step B32.

[0033] Step B31: The first system remains in recovery mode, the second system enters refrigerant cooling mode, and then proceeds to step B4;

[0034] Step B32: The first system remains in recycling mode, the second system enters compression mode, and then proceeds to step B4;

[0035] Step B4: Check whether the supply air temperature of the blower is greater than the third supply air temperature value within the fourth time period, and the third supply air temperature value is less than the second supply air temperature value; if yes, proceed to step B5; if no, proceed to step D.

[0036] Step B5: The first system enters compression mode or refrigerant cooling mode, and then proceeds to step S1.

[0037] The present invention is further configured to switch from fluorine cooling mode to recycling mode, including the following steps:

[0038] E1. Gradually open the proportional two-way valve at T1, open the proportional two-way valve to the first opening degree at T2, keep the proportional two-way valve at the first opening degree until T3, and perform automatic adjustment at T4.

[0039] E2. At time T2, one outlet of the three-way valve gradually closes while the other outlet gradually opens. At time T3, one outlet of the three-way valve remains completely closed while the other outlet remains completely open.

[0040] E3. Gradually shut down the exhaust fan at T3, and keep the exhaust fan completely shut down at T4.

[0041] The present invention is further configured to switch from compression mode to recycling mode, including the following steps:

[0042] F1. Gradually open the proportional two-way valve at T5, open the proportional two-way valve to the first opening degree at T6, keep the proportional two-way valve at the first opening degree until T8, and perform automatic adjustment at T9.

[0043] F2. At T6, one outlet of the three-way valve gradually closes while the other outlet gradually opens. At T7, one outlet of the three-way valve remains completely closed while the other outlet remains completely open.

[0044] F3. Gradually shut down the exhaust fan at T7, and keep the exhaust fan completely off between T7 and T8.

[0045] F4. Gradually turn on the refrigerant pump at T7, and keep the refrigerant pump fully open at T8 before automatically adjusting.

[0046] F5. Gradually shut off the compressor at T8, and keep the compressor completely off between T8 and T9.

[0047] The present invention is further configured to include the following steps when exiting the recycling mode:

[0048] G1. At T10, turn the exhaust fan to the first speed and maintain it until T11. At T11, turn the exhaust fan to the second speed and maintain the second speed.

[0049] G2. At T11, one outlet of the three-way valve gradually opens while the other outlet gradually closes. At T12, the three-way valve is in the first state and remains in the first state until T13. At T13, one outlet of the three-way valve continues to gradually open while the other outlet continues to gradually close. At T14, one outlet of the three-way valve remains fully open while the other outlet remains fully closed.

[0050] The beneficial effects of the present invention are as follows: By setting up a first system and a second system, the present invention enables the entire air conditioning system to have multiple cooling modes; both other systems are equipped with a recovery mode, which bypasses the condenser through a three-way valve, so that the refrigerant enters the heat exchange channel of the heat exchanger after absorbing heat in the evaporator, thereby transferring the heat to the water supply channel of the heat exchanger, thus recovering the heat generated by the air conditioning system. Attached Figure Description

[0051] The invention will be further illustrated with reference to the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the invention. For those skilled in the art, other drawings can be obtained based on the following drawings without any creative effort.

[0052] Figure 1 This is a block diagram of the present invention;

[0053] Figure 2 This is a system flowchart of the present invention;

[0054] Figure 3 This is a timing diagram of the conversion from the fluorine cooling mode to the recovery mode in this invention;

[0055] Figure 4 This is a timing diagram showing the conversion from compression mode to recycling mode in this invention;

[0056] Figure 5 This is a timing diagram of the invention exiting the recycling mode;

[0057] The components include: 1. Compressor; 11. Compression check valve; 2. Fluorine pump; 21. Fluorine cooling check valve; 3. Condenser; 31. Exhaust fan; 4. Three-way valve; 5. Evaporator; 51. Blower; 6. Heat exchanger; 61. Water supply channel; 62. Heat exchange channel; 63. Proportional two-way valve; 64. Differential pressure switch; 7. Liquid receiver; 8. Electronic expansion valve; 9. Gas-liquid separator. Detailed Implementation

[0058] The present invention will be further described in conjunction with the following embodiments.

[0059] Depend on Figures 1 to 5 As can be seen, the air conditioning system for heat recovery in refrigerant cooling mode described in this embodiment includes a first system, a second system, and a recovery system; both the first system and the second system include a compressor 1, a compression check valve 11, a refrigerant pump 2, a refrigerant cooling check valve 21, a condenser 3, a three-way valve 4, and an evaporator 5; a blower 51 is provided at the evaporator 5; and an exhaust fan 31 is provided at the condenser 3.

[0060] The recovery system includes a heat exchanger 6 and a proportional two-way valve 63; the heat exchanger 6 includes a water supply channel 61 and two heat exchange channels 62; the proportional two-way valve 63 is connected to the water supply channel 61; a differential pressure switch 64 is provided between the inlet and outlet of the water supply channel 61; the two heat exchange channels 62 are respectively connected to the first system and the second system.

[0061] Both the first system and the second system include a fluorine cooling mode, a compression mode, and a recovery mode.

[0062] Specifically, the air conditioning system that recovers heat energy in the refrigerant cooling mode described in this embodiment can simultaneously activate the compression mode of both systems and the refrigerant cooling mode of both systems by setting up a first system and a second system, or one system can activate the compression mode and the other system can activate the refrigerant cooling mode, so that the entire air conditioning system has multiple cooling modes.

[0063] Both other systems are equipped with a recovery mode. In the recovery mode, the condenser 3 is bypassed through the three-way valve 4, so that the refrigerant enters the heat exchange channel 62 of the heat exchanger 6 after absorbing heat through the evaporator 5. This allows the heat to be transferred to the water supply channel 61 of the heat exchanger 6, heating the water in the water supply channel 61, thereby recovering the heat generated by the air conditioning system.

[0064] In this embodiment, an air conditioning system that recovers heat energy in fluorine cooling mode has the following flow path for the refrigeration system in both the first and second systems in compression mode: compressor 1 - three-way valve 4 - condenser 3 - fluorine cooling one-way valve 21 - evaporator 5 - compressor 1.

[0065] In refrigerant cooling mode, the flow path of the refrigeration system in both the first and second systems is: refrigerant pump 2 - evaporator 5 - compressor check valve 11 - three-way valve 4 - condenser 3 - refrigerant pump 2;

[0066] In recovery mode, the flow path of the refrigeration system in both the first and second systems is: refrigerant pump 2 - evaporator 5 - compression check valve 11 - three-way valve 4 - heat exchange channel 62 - refrigerant pump 2.

[0067] Specifically, the air conditioning system with heat recovery in refrigerant cooling mode described in this embodiment only requires starting the refrigerant pump 2 and does not require starting the compressor 1. The above settings can provide enough heat to heat the water in the water supply channel 61, which is suitable for scenarios where the water temperature requirement in the water supply channel 61 is low. This can reduce the energy efficiency of the entire air conditioning system and reduce the waste of resources.

[0068] This embodiment describes an air conditioning system for heat recovery in refrigerant cooling mode. The compressor 1 is connected in parallel with a compression check valve 11; the refrigerant pump 2 is connected in parallel with a refrigerant cooling check valve 21; one end of the compressor 1 is connected to the inlet end of a three-way valve 4; one outlet end of the three-way valve 4 is connected to one end of a condenser 3; the other end of the condenser 3 is connected to one end of the refrigerant pump 2; the other outlet end of the three-way valve 4 is connected to the other end of the condenser 3 via a heat exchange channel 62; the other end of the refrigerant pump 2 is connected to one end of an evaporator 5; and the other end of the evaporator 5 is connected to the other end of the compressor 1.

[0069] This embodiment describes an air conditioning system for heat recovery in refrigerant cooling mode. A liquid storage tank 7 is provided between one end of the condenser 3 and one end of the refrigerant pump 2; an electronic expansion valve 8 is provided between one end of the refrigerant pump 2 and one end of the evaporator 5; a gas-liquid separator 9 is provided between one end of the evaporator 5 and one end of the compressor 1; a branch connecting the compressor 1 and the gas-liquid separator 9 is connected in parallel across the two ends of a compression check valve 11. These features make the entire air conditioning system more stable and reliable.

[0070] The evaporators 5 of the first system and the second system are arranged in an overlapping manner. This arrangement makes the entire air conditioning system more stable and reliable, and reduces the number of exhaust fans 31 and supply fans 51, effectively saving costs. The evaporator 5 of the second system is located between the evaporator 5 of the first system and the supply fan 51. Specifically, after the evaporator 5 of the second system overlaps with the evaporator 5 of the first system, the evaporator 5 of the second system is located on the leeward side relative to the evaporator 5 of the first system. The airflow passes through the evaporator 5 of the first system first and then through the evaporator 5 of the second system. Therefore, when the supply fan 51 is shared, the heat exchange efficiency of the second system at the evaporator 5 is lower than that of the first system. Therefore, the second system is given priority in the advanced heat recovery mode.

[0071] The air conditioning system for heat recovery in refrigerant cooling mode described in this embodiment includes the following steps:

[0072] Step S1: Check if the proportional two-way valve 63 is open to the first opening degree. If yes, proceed to step S2; otherwise, the first system and the second system maintain the current mode. The first opening degree can be 100%.

[0073] Step S2: Check if the differential pressure switch 64 is open. If yes, proceed to step S3; otherwise, the first system and the second system maintain the current mode.

[0074] Step S3: Check whether the return water temperature at the inlet of the water supply channel 61 is lower than the first return water temperature value. If yes, proceed to step A; if no, proceed to step S4. The first return water temperature value can be 10 degrees.

[0075] Step A: Both the first and second systems enter recycling mode; then proceed to step B1;

[0076] Step S4: Detect whether the return water temperature at the inlet of the water supply channel 61 is lower than the second return water temperature value. If the second return water temperature value is greater than the first return water temperature value, proceed to step C; otherwise, the first system and the second system maintain the current mode; wherein the second return water temperature value can be 13 degrees.

[0077] Step C: The first system maintains its current mode, while the second system enters recycling mode; then proceed to step D.

[0078] Specifically, in the air conditioning system with heat recovery in refrigerant cooling mode described in this embodiment, the proportional two-way valve 63 is fully opened first, and the water flow in the water supply channel 61 is determined to be sufficient by the differential pressure switch 64. Then, it is determined whether the heating is sufficient, thereby determining the number of systems entering the recovery mode. When the water temperature in the water supply channel 61 is below 10 degrees Celsius, two systems are needed to heat the water supply channel 61. When the water temperature in the water supply channel 61 is greater than 10 degrees Celsius but less than 13 degrees Celsius, only one system is needed to heat the water supply channel 61. The above settings can ensure that the return water temperature meets the standard, thereby ensuring sufficient heating.

[0079] The air conditioning system for heat recovery in refrigerant cooling mode described in this embodiment further includes the following steps:

[0080] Step D: Detect the water supply temperature at the outlet of the water supply channel 61, the air supply temperature of the blower 51, and the opening degree of the proportional two-way valve 63; if the water supply temperature at the outlet of the water supply channel 61 is less than the set water supply temperature value in the first time, the air supply temperature of the blower 51 is less than the first air supply temperature value in the second time, and the opening degree of the proportional two-way valve 63 is less than the second opening degree, then proceed to step A; the second opening degree is less than the first opening degree.

[0081] Specifically, assuming that the water supply temperature at the outlet of the water supply channel 61 is lower than the set water supply temperature within 45 seconds, the air supply temperature of the blower 51 is lower than the first air supply temperature value within 45 seconds, and the opening degree of the proportional two-way valve 63 is less than 65%, it indicates that the entire system has insufficient heating and sufficient cooling for a long time. At this time, both systems will enter the recovery mode to improve the heating of the water supply channel 61.

[0082] Step D further includes: if the proportional two-way valve 63 opens to the third opening degree and the air supply temperature of the blower 51 is greater than the second air supply temperature value within the third time period, then proceed to step D1; the third opening degree is less than the first opening degree and greater than the second opening degree; wherein the third opening degree can be 85%, the third time period can be 5 seconds, and the second air supply temperature value can be 23 degrees.

[0083] Step D1: Check if the outdoor temperature is lower than the outdoor temperature setpoint. If yes, proceed to step D11; otherwise, proceed to step D12. The outdoor temperature can be determined by collecting the temperature at the exhaust fan 31. The outdoor temperature setpoint can be 8 degrees Celsius.

[0084] Step D11: The first system maintains the current mode, the second system enters the refrigerant cooling mode, and then proceeds to step S1;

[0085] Step D12: The first system maintains the current mode, the second system enters the compression mode, and then proceeds to step S1.

[0086] Specifically, since the air supply temperature of the blower 51 is greater than the second air supply temperature value in the third time period, it indicates that the cooling effect is poor. Therefore, in order to ensure the overall cooling effect, the second system needs to be unloaded in recovery mode, and the outdoor temperature determines whether the second system enters compression mode or refrigerant cooling mode after unloading.

[0087] The air conditioning system for heat recovery in refrigerant cooling mode described in this embodiment further includes the following steps:

[0088] Step B1: Check if the proportional two-way valve 63 is open to the third degree. If yes, proceed to step B2; otherwise, the first and second systems remain in recovery mode. The third degree can be 85%.

[0089] Step B2: Check whether the air supply temperature of the blower 51 is greater than the second air supply temperature value within the third time period. If yes, proceed to step B3; otherwise, the first system and the second system maintain the recovery mode. The third time period can be 5 seconds, and the second air supply temperature value can be 23 degrees.

[0090] Step B3: Check if the outdoor temperature is lower than the outdoor temperature setpoint. If yes, proceed to step B31; otherwise, proceed to step B32. The outdoor temperature can be determined by collecting the temperature at the exhaust fan 31. The outdoor temperature setpoint can be 8 degrees Celsius.

[0091] Step B31: The first system remains in recovery mode, the second system enters refrigerant cooling mode, and then proceeds to step B4;

[0092] Step B32: The first system remains in recycling mode, the second system enters compression mode, and then proceeds to step B4;

[0093] Step B4: Check whether the air supply temperature of the blower 51 is greater than the third air supply temperature value within the fourth time period. If the third air supply temperature value is less than the second air supply temperature value, proceed to step B5; otherwise, proceed to step D. The fourth time period can be 30 seconds, and the second air supply temperature value can be 22 degrees.

[0094] Step B5: The first system enters compression mode or refrigerant cooling mode, and then proceeds to step S1.

[0095] Specifically, since the supply air temperature of the blower 51 is higher than the second supply air temperature value in the third time period, it indicates poor cooling effect. Therefore, to ensure the overall cooling effect, the second system needs to be unloaded in recovery mode. The outdoor temperature determines whether the second system enters compression mode or refrigerant cooling mode after unloading. The cooling capacity provided to the evaporator 5 by the water-cooled plate heat exchanger 6 is less than the cooling capacity provided to the evaporator 5 after heat exchange by the air-cooled condenser 3. Although there is a heat recovery function, the computer room air conditioner prioritizes cooling capacity. Therefore, when the cooling capacity is insufficient, the water-cooled heat recovery needs to be unloaded to switch to air cooling; conversely, when the cooling capacity is sufficient, the air-cooled condenser 3 can be switched to the water-cooled plate heat exchanger 6. Shutting down the blower 51 while prioritizing cooling can reduce energy consumption, and the recovered heat can be used for further energy saving.

[0096] If the air supply temperature of the blower 51 is greater than the third air supply temperature value in the fourth time period, it indicates that the overall cooling effect is still insufficient. At this time, the first system should also exit the recovery mode.

[0097] This control method ensures sufficient water flow in the unloaded system recovery mode. Because the cooling supply air temperature is too high, the cooling capacity is insufficient, so it is necessary to unload and exit the recovery mode. The outdoor temperature determines whether the system enters compressor circulation or refrigerant pump circulation after unloading and recovery mode. If both systems are in recovery mode, it is also necessary to determine whether to exit the recovery mode of the other system based on the supply air temperature.

[0098] The air conditioning system for heat recovery in refrigerant cooling mode described in this embodiment, switching from refrigerant cooling mode to recovery mode, includes the following steps:

[0099] E1. Gradually open the proportional two-way valve 63 at T1, open the proportional two-way valve 63 to the first opening degree at T2, keep the proportional two-way valve 63 at the first opening degree until T3, and perform automatic adjustment at T4.

[0100] E2. At time T2, one outlet of the three-way valve 4 gradually closes while the other outlet of the three-way valve 4 gradually opens. At time T3, one outlet of the three-way valve 4 remains completely closed while the other outlet of the three-way valve 4 remains completely open.

[0101] E3. At T3, gradually shut down the exhaust fan 31, and at T4, keep the exhaust fan 31 completely shut down.

[0102] Specifically, through the above settings, when switching from refrigerant cooling mode to recovery mode, the proportional two-way valve 63 is gradually opened first. When the proportional two-way valve 63 is opened to 100%, the three-way valve 4 is controlled to allow the refrigerant to start switching between the condenser 3 and the heat exchange channel 62. After the complete switching, the exhaust fan 31 is gradually turned off.

[0103] The air conditioning system for heat recovery in refrigerant cooling mode described in this embodiment, which switches from compression mode to recovery mode, includes the following steps:

[0104] F1. Gradually open the proportional two-way valve 63 at T5, open the proportional two-way valve 63 to the first opening degree at T6, keep the proportional two-way valve 63 at the first opening degree until T8, and perform automatic adjustment at T9.

[0105] F2. At T6, one outlet of the three-way valve 4 gradually closes while the other outlet of the three-way valve 4 gradually opens. At T7, one outlet of the three-way valve 4 remains completely closed while the other outlet of the three-way valve 4 remains completely open.

[0106] F3. Gradually shut off exhaust fan 31 at T7, and keep exhaust fan 31 completely off between T7 and T8.

[0107] F4. Gradually turn on the refrigerant pump 2 at T7, and keep the refrigerant pump 2 fully open at T8 before automatically adjusting.

[0108] F5. At T8, gradually shut down compressor 1, and keep compressor 1 completely off between T8 and T9.

[0109] Specifically, through the above settings, when switching from compression mode to recovery mode, the proportional two-way valve 63 is gradually opened first. When the proportional two-way valve 63 is opened to 100%, the three-way valve 4 is controlled to allow the refrigerant to start switching between the condenser 3 and the heat exchange channel 62. After the complete switching, the exhaust fan 31 is gradually turned off while the refrigerant pump 2 is gradually turned on. When the refrigerant pump 2 is fully turned on, the compressor 1 is gradually turned off, thereby maintaining the stability of the overall system.

[0110] The air conditioning system for heat recovery in refrigerant cooling mode described in this embodiment includes the following steps when exiting the recovery mode:

[0111] G1. At T10, turn on the exhaust fan 31 to the first speed and maintain it until T11. At T11, turn on the exhaust fan 31 to the second speed and maintain the second speed.

[0112] G2. At T11, one outlet of the three-way valve 4 gradually opens while the other outlet of the three-way valve 4 gradually closes. At T12, the three-way valve 4 is in the first state and remains in the first state until T13. At T13, one outlet of the three-way valve 4 continues to gradually open while the other outlet of the three-way valve 4 continues to gradually close. At T14, one outlet of the three-way valve 4 remains fully open while the other outlet of the three-way valve 4 remains fully closed.

[0113] Specifically, when exiting the recovery mode, the three-way valve 4 needs to remain in the first state for a certain period of time to establish a stable heat exchange relationship with the refrigerant-cooled condenser 3 on the air-cooled side. During load reduction, the three-way valve 4 pauses at the first state, i.e., 50% opening, to ensure that the refrigerant-cooled condenser 3 on the air-cooled side establishes a stable heat exchange relationship. Because the piping of the air-cooled condenser 3 is longer, the pause in the opening of the three-way valve 4 is to ensure that when switching from the water-cooled plate heat exchanger 6 to the air-cooled condenser 3, sufficient refrigerant passes through the condenser 3 and enters the liquid receiver 7, ensuring a sufficient liquid level. Compared to direct switching, insufficient refrigerant in the piping of the air-cooled condenser 3 would cause all the refrigerant in the liquid receiver 7 to migrate to the evaporator 5, resulting in a shortage of refrigerant pump 2.

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A control method for an air conditioning system performing heat recovery in refrigerant cooling mode, characterized in that: It includes a first system, a second system, and a recovery system; both the first system and the second system include a compressor (1), a compression check valve (11), a refrigerant pump (2), a refrigerant cooling check valve (21), a condenser (3), a three-way valve (4), and an evaporator (5); a blower (51) is provided at the evaporator (5); an exhaust fan (31) is provided at the condenser (3); The recovery system includes a heat exchanger (6) and a proportional two-way valve (63); the heat exchanger (6) includes a water supply channel (61) and two heat exchange channels (62); the proportional two-way valve (63) is connected to the water supply channel (61); a differential pressure switch (64) is provided between the inlet and outlet of the water supply channel (61); the two heat exchange channels (62) are respectively connected to the first system and the second system; Both the first system and the second system include a fluorine cooling mode, a compression mode, and a recovery mode; In compression mode, the flow path of the refrigeration system in both the first and second systems is: compressor (1) - three-way valve (4) - condenser (3) - refrigerant check valve (21) - evaporator (5) - compressor (1); In fluorine-cooled mode, the flow path of the refrigeration system in the first system and the second system is: fluorine pump (2) - evaporator (5) - compression check valve (11) - three-way valve (4) - condenser (3) - fluorine pump (2); In the recovery mode, the flow path of the refrigeration system in both the first and second systems is: refrigerant pump (2) - evaporator (5) - compression check valve (11) - three-way valve (4) - heat exchange channel (62) - refrigerant pump (2); The compressor (1) is connected in parallel with the compression check valve (11); the fluorine pump (2) is connected in parallel with the fluorine cooling check valve (21); one end of the compressor (1) is connected to the inlet end of the three-way valve (4); one outlet end of the three-way valve (4) is connected to one end of the condenser (3); the other end of the condenser (3) is connected to one end of the fluorine pump (2); the other outlet end of the three-way valve (4) is connected to the other end of the condenser (3) through the heat exchange channel (62); the other end of the fluorine pump (2) is connected to one end of the evaporator (5); the other end of the evaporator (5) is connected to the other end of the compressor (1); Includes the following steps: Step S1: Check if the proportional two-way valve (63) is open to the first opening degree. If yes, proceed to step S2; otherwise, the first system and the second system maintain the current mode. Step S2: Check if the differential pressure switch (64) is open. If yes, proceed to step S3; otherwise, the first system and the second system maintain the current mode. Step S3: Check whether the return water temperature at the inlet of the water supply channel (61) is lower than the first return water temperature value. If yes, proceed to step A; otherwise, proceed to step S4. Step A: Both the first and second systems enter recycling mode; then proceed to step B1; Step S4: Detect whether the return water temperature at the inlet of the water supply channel (61) is lower than the second return water temperature value. If the second return water temperature value is greater than the first return water temperature value, proceed to step C; otherwise, the first system and the second system maintain the current mode. Step C: The first system maintains its current mode, while the second system enters recycling mode; then proceed to step D. It also includes the following steps: Step D: Detect the water supply temperature at the outlet of the water supply channel (61), the air supply temperature of the blower (51), and the opening degree of the proportional two-way valve (63); if the water supply temperature at the outlet of the water supply channel (61) is less than the set water supply temperature in the first time, the air supply temperature of the blower (51) is less than the first air supply temperature value in the second time, and the opening degree of the proportional two-way valve (63) is less than the second opening degree, then proceed to step A; the second opening degree is less than the first opening degree. Step D further includes: if the proportional two-way valve (63) is opened to the third opening degree and the air supply temperature of the blower (51) is greater than the second air supply temperature value in the third time period, then proceed to step D1; the third opening degree is less than the first opening degree and greater than the second opening degree. Step D1: Check if the outdoor temperature is lower than the outdoor temperature set value. If yes, proceed to step D11; otherwise, proceed to step D12. Step D11: The first system maintains the current mode, the second system enters the refrigerant cooling mode, and then proceeds to step S1; Step D12: The first system maintains the current mode, the second system enters the compression mode, and then proceeds to step S1.

2. The control method for an air conditioning system performing heat recovery in refrigerant cooling mode according to claim 1, characterized in that: A liquid storage tank (7) is provided between the other end of the condenser (3) and one end of the fluorine pump (2); an electronic expansion valve (8) is provided between the other end of the fluorine pump (2) and one end of the evaporator (5); a gas-liquid separator (9) is provided between the other end of the evaporator (5) and the other end of the compressor (1); the branch connecting the compressor (1) and the gas-liquid separator (9) is connected in parallel at both ends of the compression check valve (11); The evaporator (5) of the first system and the evaporator (5) of the second system are arranged overlappingly; the evaporator (5) of the second system is located between the evaporator (5) of the first system and the blower (51).

3. The control method for an air conditioning system performing heat recovery in refrigerant cooling mode according to claim 1, characterized in that: It also includes the following steps: Step B1: Check if the proportional two-way valve (63) is open to the third degree. If yes, proceed to step B2; otherwise, the first system and the second system remain in recovery mode. Step B2: Check whether the air supply temperature of the blower (51) is greater than the second air supply temperature value within the third time period. If yes, proceed to step B3; otherwise, the first system and the second system maintain the recovery mode. Step B3: Check if the outdoor temperature is lower than the outdoor temperature setting. If yes, proceed to step B31; otherwise, proceed to step B32. Step B31: The first system remains in recovery mode, the second system enters refrigerant cooling mode, and then proceeds to step B4; Step B32: The first system remains in recycling mode, the second system enters compression mode, and then proceeds to step B4; Step B4: Check whether the air supply temperature of the blower (51) is greater than the third air supply temperature value in the fourth time period, and the third air supply temperature value is less than the second air supply temperature value. If yes, proceed to step B5; otherwise, proceed to step D. Step B5: The first system enters compression mode or refrigerant cooling mode, and then proceeds to step S1.

4. The control method for an air conditioning system performing heat recovery in refrigerant cooling mode according to claim 1, characterized in that: Switching from fluorine-cooled mode to recycling mode includes the following steps: E1. Gradually open the proportional two-way valve (63) at T1, open the proportional two-way valve (63) to the first opening degree at T2, keep the proportional two-way valve (63) at the first opening degree until T3, and perform automatic adjustment at T4. E2. At T2, one outlet of the three-way valve (4) gradually closes while the other outlet of the three-way valve (4) gradually opens. At T3, one outlet of the three-way valve (4) remains completely closed while the other outlet of the three-way valve (4) remains completely open. E3. At T3, gradually shut down the exhaust fan (31), and at T4, keep the exhaust fan (31) completely shut down.

5. The control method for an air conditioning system performing heat recovery in refrigerant cooling mode according to claim 1, characterized in that: Switching from compression mode to recycling mode includes the following steps: F1. Gradually open the proportional two-way valve (63) at T5, open the proportional two-way valve (63) to the first opening degree at T6, keep the proportional two-way valve (63) at the first opening degree until T8, and perform automatic adjustment at T9. F2. At T6, one outlet of the three-way valve (4) gradually closes while the other outlet of the three-way valve (4) gradually opens. At T7, one outlet of the three-way valve (4) remains completely closed while the other outlet of the three-way valve (4) remains completely open. F3. Gradually shut off the exhaust fan (31) at T7, and keep the exhaust fan (31) completely shut off between T7 and T8; F4. Gradually turn on the fluorine pump (2) at T7, and automatically adjust it after keeping the fluorine pump (2) fully open at T8. F5. At T8, gradually shut down the compressor (1), and keep the compressor (1) completely off between T8 and T9.

6. The control method for an air conditioning system performing heat recovery in refrigerant cooling mode according to claim 1, characterized in that: When exiting recycling mode, the following steps are included: G1. At T10, turn on the exhaust fan (31) to the first speed and maintain it until T11. At T11, turn on the exhaust fan (31) to the second speed and maintain it. G2. At T11, one outlet of the three-way valve (4) gradually opens while the other outlet of the three-way valve (4) gradually closes. At T12, the three-way valve (4) is in the first state and remains in the first state until T13. At T13, one outlet of the three-way valve (4) continues to gradually open while the other outlet of the three-way valve (4) continues to gradually close. At T14, one outlet of the three-way valve (4) remains fully open while the other outlet of the three-way valve (4) remains fully closed.

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