A multifunctional air conditioning unit and control method thereof

Abstract

The present invention discloses a multifunctional air conditioning unit and a control method thereof, comprising a compressor, a four-way reversing valve, a first heat exchanger, a second heat exchanger, a third heat exchanger, a unidirectional control valve assembly and a throttling mechanism; the exhaust port and the air intake port of the compressor are connected to the four-way reversing valve, the four-way reversing valve is respectively connected to the first heat exchanger and the second heat exchanger, the first heat exchanger and the second heat exchanger are connected to the unidirectional control valve assembly, the unidirectional control valve assembly is connected to the third heat exchanger, and the throttling mechanism is arranged between the unidirectional control valve assembly and the outlet of the third heat exchanger. The present invention ensures that whether the third heat exchanger participates in heat exchange or rarely participates in heat exchange, the refrigerant discharged by the compressor will always pass through the third heat exchanger, so that the refrigerant in the third heat exchanger is always in a flowing state, thereby avoiding the problem that the refrigerant does not pass through the third heat exchanger when it does not participate in heat exchange, and the oil accumulation in the third heat exchanger previously causes the dead zone oil return to be poor and damages the equipment.

Description

Technical Field

[0001] The invention belongs to the technical field of air conditioning units, and in particular relates to a multifunctional air conditioning unit and a control method thereof. Background Art

[0002] With the continuous development of my country's economy and the continuous improvement of residents' living standards, people's demand for air-conditioning functions is also increasing. At present, air-conditioning has become the infrastructure of buildings and a necessity in people's lives and work.

[0003] Specifically, from the user demand side, air conditioning units need to provide cooling, heating or domestic hot water according to the application site. Existing common air conditioning units can usually only provide cooling and heating functions, and cannot provide domestic hot water. With the development of technology, some air conditioning units can also provide cooling, heating and domestic hot water functions at the same time, but because the water heaters do not work at the same time, there may be a dead zone where oil return is not smooth and there may be a risk that some heat exchangers will freeze, which may damage the equipment in serious cases. Summary of the invention

[0004] The purpose of the present invention is to provide a multifunctional air-conditioning unit and a control method thereof, so as to solve the technical problems in the prior art that the air-conditioning unit may have poor oil return in the dead zone and the risk of freezing of some heat exchangers, which may damage the equipment in serious cases.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] On the one hand, a multifunctional air conditioning unit is provided, comprising a compressor, a four-way reversing valve, a first heat exchanger, a second heat exchanger, a third heat exchanger, a unidirectional control valve assembly and a throttling mechanism;

[0007] The exhaust port and the air intake port of the compressor are connected to the four-way reversing valve, the four-way reversing valve is respectively connected to the inlet of the first heat exchanger and the first connecting port of the second heat exchanger, the outlet of the first heat exchanger and the second connecting port of the second heat exchanger are respectively connected to the one-way control valve assembly, the one-way control valve assembly is connected to the inlet and outlet of the third heat exchanger, and the throttling mechanism is arranged between the one-way control valve assembly and the outlet of the third heat exchanger;

[0008] The unidirectional control valve assembly includes a first control valve C1, a second control valve C2, a third control valve C3 and a fourth control valve C4; one end of the first control valve C1 and one end of the fourth control valve C4 are respectively connected to the outlet of the first heat exchanger, the other end of the first control valve C1 and one end of the second control valve C2 are respectively connected to the inlet of the third heat exchanger, the other end of the second control valve C2 is connected to the second connecting port of the second heat exchanger, both ends of the third control valve C3 are respectively connected to the other end of the fourth control valve C4 and the other end of the second control valve C2, and the other end of the fourth control valve C4 is connected to the throttling mechanism.

[0009] In a possible design, a first bypass is provided between the inlet and the outlet of the third heat exchanger, and a first solenoid valve S1 is provided on the first bypass.

[0010] In a possible design, the third heat exchanger includes a first heat exchange component and a second heat exchange component, the first heat exchange component is provided with a first inlet and a first outlet, and the second heat exchange component is provided with a second inlet and a second outlet;

[0011] The other end of the first control valve C1 and one end of the second control valve C2 are respectively connected to the first inlet, and the throttling mechanism is connected to the first outlet;

[0012] The exhaust port of the compressor is directly connected to the second inlet, or the exhaust port of the compressor is connected to the second inlet after passing through the four-way reversing valve, and the four-way reversing valve is connected to the second outlet.

[0013] In one possible design, when the exhaust port of the compressor is directly connected to the second inlet, a first passage is provided between the exhaust port of the compressor and the second inlet, a second passage is provided between the four-way reversing valve and the second outlet, a third passage is provided between the first passage and the second passage, and a second solenoid valve S2 is provided on the third passage.

[0014] In one possible design, when the exhaust port of the compressor is connected to the second inlet after passing through the four-way reversing valve, the four-way reversing valve is provided with a fourth passage, and the fourth passage is provided with a first branch and a second branch, the first branch is connected to the second inlet, the second branch is connected to the second outlet, and a third solenoid valve S3 is provided on the second branch near the diversion point of the two branches.

[0015] In a possible design, a second bypass is provided on the connecting pipeline between the four-way reversing valve and the first heat exchanger, or the second bypass is provided on the connecting pipeline between the exhaust port of the compressor and the four-way reversing valve, a fourth solenoid valve S4 is provided on the second bypass, a fifth solenoid valve S5 is provided on the connecting pipeline between one end of the first bypass and the inlet of the third heat exchanger, and one end of the second bypass is connected to the connecting pipeline between the fifth solenoid valve S5 and the inlet of the third heat exchanger.

[0016] In one possible design, the first heat exchanger includes an air-cooled heat exchanger or an evaporative condenser, the second heat exchanger includes a water-cooled heat exchanger or an air-cooled heat exchanger, and / or the third heat exchanger includes a water-cooled heat exchanger or a water exchange water tank.

[0017] In a possible design, the third heat exchanger includes a first heat exchange tank and a second heat exchange tank, and the second heat exchange tank is arranged below the first heat exchange tank.

[0018] On the other hand, there is provided a control method for the multifunctional air conditioning unit as described in any possible design of the first aspect, comprising:

[0019] Determine the target operating mode on the user demand side according to the functional relationship between the temperature detection value of the current operating mode and the target temperature value;

[0020] According to the refrigerant flow direction preset in the target operation mode, the drive mechanism and / or valve on the corresponding heat exchanger side is controlled to operate or close, so that the unit operates in the target operation mode;

[0021] Among them, the temperature detection value type and the target temperature value type both include at least return water temperature, return air temperature, outlet water temperature, outlet air temperature, water tank temperature and / or ambient temperature, and the user demand side includes at least the user cooling side, heating side and / or domestic hot water side;

[0022] The target operation mode includes a basic operation mode, a semi-automatic mode and / or a fully automatic operation mode. The basic operation mode includes a cooling mode, a heating mode, a domestic hot water mode, a cooling + domestic hot water mode and / or a heating + domestic hot water mode selected by the user; the semi-automatic mode includes an automatic cooling + domestic hot water mode and / or an automatic heating + domestic hot water mode; the fully automatic operation mode is an operation mode in which the unit adaptively and automatically switches the basic operation mode according to user settings and environmental conditions.

[0023] In a possible design, controlling the driving mechanism and / or valve on the corresponding heat exchanger side to operate or close includes:

[0024] If the target operating mode is the refrigeration or heating mode, turn on the water pump or fan of the second heat exchanger, turn off the water pump of the third heat exchanger or do not operate. If a first solenoid valve S1 is provided between the inlet and outlet of the third heat exchanger, turn on the first solenoid valve S1;

[0025] If the target operating mode is the domestic hot water mode, turn on the water pump or fan of the second heat exchanger, turn on the water pump of the third heat exchanger. If a first solenoid valve S1 is provided between the inlet and outlet of the third heat exchanger, turn off the first solenoid valve S1, and operate the fan of the first heat exchanger;

[0026] If the target operating mode is the refrigeration + domestic hot water mode or the heating + domestic hot water mode, turn on the water pump or fan of the second heat exchanger, turn on the water pump of the third heat exchanger. If a first solenoid valve S1 is provided between the inlet and outlet of the third heat exchanger, turn off the first solenoid valve S1;

[0027] Among them, when switching the operating mode, it is necessary to control the four-way reversing valve to switch to the flow direction of the corresponding mode.

[0028] In a possible design, if the current operating mode is the automatic refrigeration + domestic hot water mode, determine the target operating mode on the user demand side according to the functional relationship between the temperature detection value and the target temperature value of the current operating mode, including:

[0029] 1) If HCT < ST1 - D1 and SHT1 < SHCT - D2, it is determined that the target operating mode on the user demand side is the domestic hot water mode;

[0030] 2) If HCT > ST1 + D1 and SHT1 < SHCT - D2, it is determined that the target operating mode on the user demand side is the refrigeration + domestic hot water mode;

[0031] 3) If HCT > ST1 + D1 and SHT1 > SHCT + D2, it is determined that the target operating mode on the user demand side is the refrigeration mode;

[0032] Among them, HCT represents the currently detected return water temperature, ST1 represents the target return water temperature on the refrigeration side, SHT1 represents the target temperature required on the domestic hot water side, SHCT represents the detected temperature, and D1 and D2 respectively represent the first preset deviation value and the second preset deviation value.

[0033] In a possible design, if the current operating mode is the automatic refrigeration + domestic hot water mode, determine the target operating mode on the user demand side according to the functional relationship between the temperature detection value and the target temperature value of the current operating mode, including:

[0034] Perform a weighted calculation on the temperature detection value and the target temperature value of the current operating mode to obtain the first target mode determination value F1. The calculation formula is as follows:

[0035] F1 = a1*(HCT-ST1)+b1*(SHT1-SHCT); or

[0036] F1 = a1*(HCT-ST1)+b1*(SHT1-SHCT)+c1*AT; or

[0037] F1=a1*(HCT-ST1)+b1*(SHT1-SHCT)+c1*AT+d*(HCT-ST1)*(SHT1-SHCT)+e1*(SHT1-SHCT)*AT+f1*(HCT-ST1)*AT;

[0038] Wherein, AT represents the ambient temperature, a1, b1, c1, d1, e1 and f1 represent the first weighting coefficient;

[0039] According to the value of the first target mode determination value F1, the target operation mode of the user demand side is determined as follows:

[0040] If the value of F1 is between FF1 and FF2, the target operation mode is determined to be the domestic hot water mode;

[0041] If the value of F1 is between FF3 and FF4, the target operation mode is determined to be cooling + domestic hot water mode;

[0042] If the value of F1 is between FF5 and FF6, the target operation mode is determined to be cooling mode;

[0043] Among them, FF1, FF2, FF3, FF4, FF5, and FF6 all represent preset target operating mode judgment values, and the values ​​increase in sequence.

[0044] In a possible design, if the current operation mode is the fully automatic operation mode, the target operation mode on the user demand side is determined according to the functional relationship between the temperature detection value of the current operation mode and the target temperature value, including:

[0045] According to the value of the second target mode determination value F2, the target operation mode of the user demand side is determined as follows:

[0046] F2 = a2*(HCT-ST1)+b2*(SHT1-SHCT)+c2*AT; or

[0047] F2=a2*(HCT-ST1)+b2*(SHT1-SHCT)+c2*AT+d2*(HCT-ST1)*(SHT1-SHCT)+e2*(SHT1-SHCT)*AT+f2*(SHT1-SHCT)*AT+g2*(HCT-ST1)*(SHT1-SHCT)*AT;

[0048] Wherein, a2, b2, c2, d2, e2, f2 and g2 all represent the second weighting coefficient;

[0049] If the value of F2 is between FF1 and FF2, the target operation mode is determined to be the domestic hot water mode;

[0050] If the value of F2 is between FF3 and FF4, the target operation mode is determined to be cooling + domestic hot water mode;

[0051] If the value of F2 is between FF5 and FF6, the target operation mode is determined to be cooling mode;

[0052] If the value of F2 is between FF7 and FF8, the target operation mode is determined to be heating mode;

[0053] If the value of F2 is between FF9 and FF10, the target operation mode is determined to be heating + domestic hot water mode;

[0054] Among them, FF1, FF2, FF3, FF4, FF5, FF6, FF7, FF8, FF9 and FF10 all represent preset target operating mode judgment values, and the values ​​increase in sequence.

[0055] In a possible design, according to the refrigerant flow direction preset in the target operation mode, the drive mechanism and / or valve on the corresponding heat exchanger side is controlled to perform operation or closing action, including:

[0056] According to the preset refrigerant flow direction in heating mode, if ST-CT>D3, the unit will be controlled as follows:

[0057] The first solenoid valve S1 is opened, the fifth solenoid valve S5 is closed, and the fourth solenoid valve S4 is opened. After a preset time, when the refrigerant outlet temperature of the third heat exchanger is higher than the condensing temperature, the temperature before the throttling mechanism, the water outlet temperature of the second heat exchanger, or the air outlet temperature of the second heat exchanger, the fourth solenoid valve S4 is closed;

[0058] Until ST-CT<D4, the fifth solenoid valve S5 is opened;

[0059] Among them, ST represents the target temperature value of any temperature among the return water temperature, the outlet water temperature, the return air temperature or the outlet air temperature, CT represents the return water temperature, the outlet water temperature, the return air temperature or the outlet air temperature corresponding to the target temperature value, D3 represents the third deviation value, and D4 represents the fourth deviation value.

[0060] Beneficial effects:

[0061] The present invention adds a third heat exchanger, a corresponding one-way valve and a four-way reversing valve in the air-conditioning unit, and by setting the corresponding refrigerant flow directions of the unit in different operating modes, the refrigerant discharged from the compressor will always pass through the third heat exchanger regardless of whether the third heat exchanger participates in heat exchange or rarely participates in heat exchange, so that the refrigerant in the third heat exchanger is always in a flowing state, thereby avoiding the problem that when the third heat exchanger does not participate in heat exchange, the refrigerant does not pass through, the oil accumulation in the third heat exchanger causes the dead zone oil return to be poor, thereby damaging the equipment, and there may be a risk of freezing due to the evaporation of the heat exchanger refrigerant absorbing heat; by setting the first Bypass, a first solenoid valve S1 is set on the first bypass, so that the flow rate of the refrigerant passing through the third heat exchanger and the first bypass is adjusted by controlling the first solenoid valve S1, so that when the third heat exchanger is not involved in heat exchange, there is still a small amount of refrigerant flowing inside, while most of the refrigerant is controlled to pass through the first bypass, thereby reducing the pressure drop and improving the performance of the equipment; by setting the third heat exchanger into two groups of heat exchange components, and setting a second inlet and a second outlet, when the compressor exhaust port is directly connected to the second inlet of the third heat exchanger, due to the higher temperature of the compressor exhaust port, higher temperature domestic hot water can be directly obtained to meet user needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 A schematic diagram of the structure of the multifunctional air-conditioning unit provided by the present invention;

[0063] Figure 2 Another structural schematic diagram of the multifunctional air-conditioning unit provided by the present invention;

[0064] Figure 3 Another structural schematic diagram of the multifunctional air-conditioning unit provided by the present invention;

[0065] Figure 4 Another structural schematic diagram of the multifunctional air-conditioning unit provided by the present invention;

[0066] Figure 5 Another structural schematic diagram of the multifunctional air-conditioning unit provided by the present invention;

[0067] Figure 6 Another structural schematic diagram of the multifunctional air-conditioning unit provided by the present invention;

[0068] Figure 7 Another structural schematic diagram of the multifunctional air-conditioning unit provided by the present invention;

[0069] Figure 8 A flow chart of the control method of the multifunctional air-conditioning unit provided by the present invention.

[0070] Among them, 1-compressor; 1a-exhaust port; 1b-intake port; 2-four-way reversing valve; 3-first heat exchanger; 4-second heat exchanger; 41-first connecting port; 42-second connecting port; 5-third heat exchanger; 51-first inlet; 52-first outlet; 53-second inlet; 54-second outlet; 6-single-flow control valve assembly; 7-throttling mechanism; 8-first bypass; 9-first passage; 10-second passage; 11-third passage; 12-fourth passage; 121-first branch; 122-second branch; 13-second bypass. DETAILED DESCRIPTION

[0071] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the present invention will be briefly introduced below in combination with the drawings and the description of the embodiments or the prior art. Obviously, the following description of the structure of the drawings is only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention.

[0072] Embodiment 1

[0073] like Figure 1 As shown, the present embodiment provides a multifunctional air conditioning unit, including a compressor 1, a four-way reversing valve 2, a first heat exchanger 3, a second heat exchanger 4, a third heat exchanger 5, a single-flow control valve assembly 6 and a throttling mechanism 7;

[0074] The exhaust port 1a and the air intake port 1b of the compressor 1 are connected to the four-way reversing valve 2, and the four-way reversing valve 2 is respectively connected to the inlet of the first heat exchanger 3 and the first connecting port 41 of the second heat exchanger 4, and the outlet of the first heat exchanger 3 and the second connecting port 42 of the second heat exchanger 4 are respectively connected to the one-way control valve assembly 6, and the one-way control valve assembly 6 is connected to the inlet and outlet of the third heat exchanger 5, and the throttling mechanism 7 is arranged between the one-way control valve assembly 6 and the outlet of the third heat exchanger 5;

[0075] The one-way control valve assembly 6 includes a first control valve C1, a second control valve C2, a third control valve C3 and a fourth control valve C4; one end of the first control valve C1 and one end of the fourth control valve C4 are respectively connected to the outlet of the first heat exchanger 3, the other end of the first control valve C1 and one end of the second control valve C2 are respectively connected to the inlet of the third heat exchanger 5, the other end of the second control valve C2 is connected to the second connecting port 42 of the second heat exchanger 4, both ends of the third control valve C3 are respectively connected to the other end of the fourth control valve C4 and the other end of the second control valve C2, and the other end of the fourth control valve C4 is connected to the throttling mechanism 7.

[0076] Preferably, the four-way reversing valve 2 includes a first channel, a second channel, a third channel and a fourth channel; the first channel is connected to the exhaust port 1a of the compressor 1, the second channel is connected to the intake port 1b of the compressor 1, the third channel is connected to the inlet of the first heat exchanger 3, and the fourth channel is connected to the first connecting port 41 of the second heat exchanger 4.

[0077] Preferably, the one-way flow control valve includes a one-way valve or an electric valve, and the electric valve can be used as a one-way valve by controlling the flow direction of the electric valve.

[0078] It should be noted that, based on the above settings, the refrigerant flow direction of the unit in each operating mode in this embodiment is as follows:

[0079] (1) Refrigerant flow direction in cooling mode: starting from compressor 1, passing through the exhaust port 1a of compressor 1, four-way reversing valve 2, first heat exchanger 3, first control valve C1, third heat exchanger 5, throttling mechanism 7, third control valve C3, and finally returning to compressor 1 through the air intake port 1b of compressor 1; wherein, by controlling the driving mechanism of the third heat exchanger 5 corresponding to the use side, for example, turning off the water pump, the third heat exchanger 5 can be made not to participate in heat exchange or to participate in heat exchange only to a very small extent;

[0080] (2) Refrigerant flow direction in heating mode: starting from compressor 1, passing through the exhaust port 1a of compressor 1, four-way reversing valve 2, second heat exchanger 4, second control valve C2, third heat exchanger 5, throttling mechanism 7, fourth control valve C4, first heat exchanger 3, four-way reversing valve 2, and finally returning to compressor 1 through the suction port 1b of compressor 1; wherein, by controlling the driving mechanism of the corresponding use side of the second heat exchanger 4, for example, turning off the water pump, the third heat exchanger 5 can be made not to participate in heat exchange or to participate in heat exchange only to a very small extent;

[0081] (3) Refrigerant flow direction in domestic hot water mode: starting from compressor 1, passing through the exhaust port 1a of compressor 1, four-way reversing valve 2, second heat exchanger 4, second control valve C2, third heat exchanger 5, throttling mechanism 7, fourth control valve C4, first heat exchanger 3, four-way reversing valve 2, and finally returning to compressor 1 through the air intake port 1b of compressor 1; wherein, by controlling the driving mechanism of the corresponding use side of the second heat exchanger 4, for example, turning off the water pump, the third heat exchanger 5 can be made not to participate in heat exchange or to participate in heat exchange only to a very small extent;

[0082] (4) Refrigerant flow direction in cooling + domestic hot water mode: starting from compressor 1, passing through the exhaust port 1a of compressor 1, four-way reversing valve 2, first heat exchanger 3, first control valve C1, third heat exchanger 5, throttling mechanism 7, third control valve C3, second heat exchanger 4, four-way reversing valve 2, and finally returning to compressor 1 through the suction port 1b of compressor 1;

[0083] (5) Refrigerant flow direction in heating + domestic hot water mode: Starting from compressor 1, it passes through the exhaust port 1a of compressor 1, the four-way reversing valve 2, the second heat exchanger 4, the second control valve C2, the third heat exchanger 5, the throttling mechanism 7, the fourth control valve C4, the first heat exchanger 3, the four-way reversing valve 2, and finally returns to compressor 1 through the suction port 1b of compressor 1.

[0084] Based on the above disclosed content, this embodiment adds a third heat exchanger 5, a corresponding one-way valve and a four-way reversing valve 2 in the air-conditioning unit, and sets the corresponding refrigerant flow direction of the unit under different operating modes. Regardless of whether the third heat exchanger 5 participates in heat exchange or rarely participates in heat exchange, the refrigerant discharged by the compressor 1 will always pass through the third heat exchanger 5, so that the refrigerant in the third heat exchanger 5 is always in a flowing state, thereby avoiding the problem that the refrigerant does not pass through the third heat exchanger 5 when it does not participate in heat exchange, and the oil accumulation in the third heat exchanger 5 previously causes the dead zone oil return to be poor and damage the equipment, thereby improving the equipment performance.

[0085] Embodiment 2

[0086] like Figure 2 As shown, the technical solution provided in this embodiment is a further improvement made on the basis of the first embodiment. The difference between this embodiment and the first embodiment is that:

[0087] A first bypass 8 is provided between the inlet and the outlet of the third heat exchanger 5 , and a first solenoid valve S1 is provided on the first bypass 8 .

[0088] Based on the above disclosed content, by setting a first bypass 8 between the inlet and outlet of the third heat exchanger 5, and setting a first solenoid valve S1 on the first bypass 8, the flow rate of the refrigerant passing through the third heat exchanger 5 and the first bypass 8 is adjusted by controlling the first solenoid valve S1, so that when the third heat exchanger 5 is not involved in heat exchange, there is still a small amount of refrigerant flowing inside, while most of the refrigerant is controlled to pass through the first bypass 8, thereby reducing the pressure drop and further improving the equipment performance.

[0089] Embodiment 3

[0090] like Figure 3 As shown, the technical solution provided in this embodiment is a further improvement made on the basis of the first embodiment or the second embodiment. The difference between this embodiment and the first embodiment or the second embodiment is that:

[0091] The third heat exchanger 5 includes a first heat exchange component and a second heat exchange component, wherein the first heat exchange component is provided with a first inlet 51 and a first outlet 52, and the second heat exchange component is provided with a second inlet 53 and a second outlet 54;

[0092] The other end of the first control valve C1 and one end of the second control valve C2 are respectively connected to the first inlet 51, and the throttling mechanism 7 is connected to the first outlet 52;

[0093] The exhaust port 1 a of the compressor 1 is directly connected to the second inlet 53 , or the exhaust port 1 a of the compressor 1 is connected to the second inlet 53 after passing through the four-way reversing valve 2 , and the four-way reversing valve 2 is connected to the second outlet 54 .

[0094] Based on the above disclosed content, since the highest temperature of the refrigerant in the air-conditioning unit during daily operation is about 40-50°C, but this temperature may not meet the user's demand for domestic hot water in the cold winter, therefore, in this embodiment, by configuring the third heat exchanger 5 to be two sets of heat exchange components, and configuring a second inlet 53 and a second outlet 54, when the exhaust port 1a of the compressor 1 is directly connected to the second inlet 53 of the third heat exchanger 5, since the temperature of the exhaust port 1a of the compressor 1 is relatively high, which can usually reach 70°C at most, domestic hot water with a higher temperature can be directly obtained, so as to achieve a more step to meet the user's domestic hot water demand; wherein, when the exhaust port 1a of the compressor 1 is directly connected to the second inlet 53, the gas refrigerant can all directly enter the third heat exchanger 5, so as to quickly obtain high-temperature domestic hot water, which can be suitable for scenes with high demand for hot water, such as bathing water in winter; when the exhaust port 1a of the compressor 1 is connected to the second inlet 53 through the four-way reversing valve 2, most of the gas refrigerant passes through the main circuit for refrigerant circulation, and a small part enters the third heat exchanger 5 from the second inlet 53, which can be suitable for application scenarios with low heat exchange demand, such as water for washing hands by users in winter.

[0095] Embodiment 4

[0096] The technical solution provided in this embodiment is a further improvement made on the basis of the third embodiment. The difference between this embodiment and the third embodiment is that:

[0097] like Figure 4 As shown, in a possible design, when the exhaust port 1a of the compressor 1 is directly connected to the second inlet 53, a first passage 9 is provided between the exhaust port 1a of the compressor 1 and the second inlet 53, a second passage 10 is provided between the four-way reversing valve 2 and the second outlet 54, a third passage 11 is provided between the first passage 9 and the second passage 10, and a second solenoid valve S2 is provided on the third passage 11.

[0098] like Figure 5 As shown, in another possible design, when the exhaust port 1a of the compressor 1 is connected to the second inlet 53 after passing through the four-way reversing valve 2, the four-way reversing valve 2 is provided with a fourth passage 12, and the fourth passage 12 is provided with a first branch 121 and a second branch 122, the first branch 121 is connected to the second inlet 53, the second branch 122 is connected to the second outlet 54, and a third solenoid valve S3 is provided on the second branch 122 near the diversion point between the two branches.

[0099] Based on the above disclosed content, by providing a second solenoid valve S2 on the third passage 11 or providing a third solenoid valve S3 on the second branch 122 near the diversion point between the two branches, when the refrigerant flows out from the exhaust port 1a of the compressor 1, the second solenoid valve S2 or the third solenoid valve S3 can be used to control the flow rate of the refrigerant entering the main circuit for refrigerant circulation and the branch circuit for direct heating, thereby further accurately controlling the refrigerant flow rate to meet the diverse needs of users.

[0100] Embodiment 5

[0101] The technical solution provided in this embodiment is a further improvement made on the basis of the fourth embodiment. The difference between this embodiment and the second embodiment is that:

[0102] In a possible design, a second bypass 13 is provided on the connecting pipeline between the four-way reversing valve 2 and the first heat exchanger 3, and a fourth solenoid valve S4 is provided on the second bypass, or the second bypass (13) is provided on the connecting pipeline between the exhaust port 1a of the compressor 1 and the four-way reversing valve 2, a fifth solenoid valve S5 is provided on the connecting pipeline between one end of the first bypass 8 and the inlet of the third heat exchanger 5, and one end of the second bypass 13 is connected to the connecting pipeline between the fifth solenoid valve S5 and the inlet of the third heat exchanger 5.

[0103] like Figure 6 As shown, a second bypass 13 is provided on the connecting pipeline between the four-way reversing valve 2 and the first heat exchanger 3. Figure 7 As shown, the second bypass (13) is provided on the connecting pipeline between the exhaust port 1a of the compressor 1 and the four-way reversing valve 2. Under the above two connection modes, the fourth solenoid valve S4 is controlled to be opened, and the first solenoid valve S1 and the fifth solenoid valve S5 are controlled to be closed. At this time, the gaseous refrigerant is sent into the third heat exchanger 5 through the branch of the fourth solenoid valve S4, and the liquid refrigerant originally stored in the third heat exchanger 5 is squeezed out, so that more refrigerant enters the unit circulation, and the subcooling or condensing temperature during the operation of the unit is adjusted. At this time, the third heat exchanger 5 can be used only as a liquid storage device without participating in heat recovery.

[0104] In a possible design, the first heat exchanger 3 includes an air-cooled heat exchanger or an evaporative condenser, the second heat exchanger 4 includes a water-cooled heat exchanger or an air-cooled heat exchanger, and / or the third heat exchanger 5 includes a water-cooled heat exchanger or a water exchange water tank.

[0105] In a possible design, the third heat exchanger 5 includes a first heat exchange tank and a second heat exchange tank, and the second heat exchange tank is arranged below the first heat exchange tank, so that it can be directly heated by the exhaust port 1a to produce more high-temperature domestic hot water for heat storage.

[0106] Embodiment 6

[0107] like Figure 8 As shown, the embodiment of the present application also provides a control method for the multifunctional air-conditioning unit as described in any possible design of the first aspect, including but not limited to being implemented by steps S1-S2:

[0108] Step S1. Determine the target operating mode on the user demand side according to the functional relationship between the temperature detection value of the current operating mode and the target temperature value;

[0109] It should be noted that the temperature detection value type and the target temperature value type both include at least return water temperature, return air temperature, outlet water temperature, outlet air temperature, water tank temperature and / or ambient temperature, and the user demand side includes at least the user cooling side, heating side and / or domestic hot water side;

[0110] Among them, it should be noted that the target operating mode includes a basic operating mode, a semi-automatic mode, and / or a full-automatic operating mode. The basic operating mode includes a refrigeration mode, a heating mode, a domestic hot water mode, a refrigeration + domestic hot water mode, and / or a heating + domestic hot water mode selected by the user; the semi-automatic mode includes an automatic refrigeration + domestic hot water mode and / or an automatic heating + domestic hot water mode; the full-automatic operating mode is an operating mode in which the unit automatically switches the basic operating mode adaptively according to the user settings and environmental conditions.

[0111] In step S1, if the current operating mode is the automatic refrigeration + domestic hot water mode, determine the target operating mode on the user demand side according to the functional relationship between the temperature detection value and the target temperature value of the current operating mode, including:

[0112] 1) If HCT < ST1 - D1 and SHT1 < SHCT - D2, it is determined that the target operating mode on the user demand side is the domestic hot water mode;

[0113] 2) If HCT > ST1 + D1 and SHT1 < SHCT - D2, it is determined that the target operating mode on the user demand side is the refrigeration + domestic hot water mode;

[0114] 3) If HCT > ST1 + D1 and SHT1 > SHCT + D2, it is determined that the target operating mode on the user demand side is the refrigeration mode;

[0115] Among them, HCT represents the currently detected return water temperature, ST1 represents the target return water temperature on the refrigeration side, SHT1 represents the target temperature on the domestic hot water side, SHCT represents the detected temperature, and D1 and D2 respectively represent the first preset deviation value and the second preset deviation value.

[0116] In step S1, if the current operating mode is the automatic refrigeration + domestic hot water mode, determine the target operating mode on the user demand side according to the functional relationship between the temperature detection value and the target temperature value of the current operating mode, including:

[0117] Perform a weighted calculation on the temperature detection value and the target temperature value of the current operating mode to obtain the first target mode determination value F1. The calculation formula is as follows:

[0118] F1 = a1 * (HCT - ST1) + b1 * (SHT1 - SHCT); or

[0119] F1 = a1 * (HCT - ST1) + b1 * (SHT1 - SHCT) + c1 * AT; or

[0120] F1=a1*(HCT-ST1)+b1*(SHT1-SHCT)+c1*AT+d*(HCT-ST1)*(SHT1-SHCT)+e1*(SHT1-SHCT)*AT+f1*(HCT-ST1)*AT;

[0121] Wherein, AT represents the ambient temperature, a1, b1, c1, d1, e1 and f1 represent the first weighting coefficient;

[0122] According to the value of the first target mode determination value F1, the target operation mode of the user demand side is determined as follows:

[0123] If the value of F1 is between FF1 and FF2, the target operation mode is determined to be the domestic hot water mode;

[0124] If the value of F1 is between FF3 and FF4, the target operation mode is determined to be cooling + domestic hot water mode;

[0125] If the value of F1 is between FF5 and FF6, the target operation mode is determined to be cooling mode;

[0126] Among them, FF1, FF2, FF3, FF4, FF5, and FF6 all represent preset target operating mode judgment values, and the values ​​increase in sequence.

[0127] In step S1, if the current operation mode is the fully automatic operation mode, the target operation mode on the user demand side is determined according to the functional relationship between the temperature detection value of the current operation mode and the target temperature value, including:

[0128] According to the value of the second target mode determination value F2, the target operation mode of the user demand side is determined as follows:

[0129] F2 = a2*(HCT-ST1)+b2*(SHT1-SHCT)+c2*AT; or

[0130] F2=a2*(HCT-ST1)+b2*(SHT1-SHCT)+c2*AT+d2*(HCT-ST1)*(SHT1-SHCT)+e2*(SHT1-SHCT)*AT+f2*(SHT1-SHCT)*AT+g2*(HCT-ST1)*(SHT1-SHCT)*AT;

[0131] Wherein, a2, b2, c2, d2, e2, f2 and g2 all represent the second weighting coefficient;

[0132] If the value of F2 is between FF1 and FF2, the target operation mode is determined to be the domestic hot water mode;

[0133] If the value of F2 is between FF3 and FF4, the target operation mode is determined to be cooling + domestic hot water mode;

[0134] If the value of F2 is between FF5 and FF6, the target operation mode is determined to be cooling mode;

[0135] If the value of F2 is between FF7 and FF8, the target operation mode is determined to be heating mode;

[0136] If the value of F2 is between FF9 and FF10, the target operation mode is determined to be heating + domestic hot water mode;

[0137] Among them, FF1, FF2, FF3, FF4, FF5, FF6, FF7, FF8, FF9 and FF10 all represent preset target operating mode judgment values, and the values ​​increase in sequence.

[0138] Step S2. According to the refrigerant flow direction preset in the target operation mode, control the drive mechanism and / or valve on the corresponding heat exchanger side to operate or close, so that the unit operates in the target operation mode;

[0139] In step S2, controlling the drive mechanism and / or valve on the corresponding heat exchanger side to operate or close includes:

[0140] If the target operation mode is cooling or heating mode, the water pump or fan of the second heat exchanger 4 is turned on, and the water pump of the third heat exchanger 5 is turned off or not operated. If a first solenoid valve S1 is provided between the inlet and outlet of the third heat exchanger 5, the first solenoid valve S1 is turned on;

[0141] Specifically, if the second heat exchanger 4 is a water-cooled heat exchanger, then its water pump is operated accordingly; if the second heat exchanger 4 is an air-cooled heat exchanger, then its fan is operated accordingly; if the third heat exchanger 5 is a water-cooled heat exchanger, then its water pump is turned off; if the third heat exchanger 5 is a water tank heat exchanger (equivalent to static heating of water), there is no need to perform this action (i.e., the third heat exchanger 5 does not operate); if a first solenoid valve S1 is provided between the inlet and outlet of the third heat exchanger 5, then the first solenoid valve S1 is opened; preferably, the fan corresponding to the first heat exchanger 3 can also be opened as needed.

[0142] If the target operation mode is the domestic hot water mode, the water pump or fan of the second heat exchanger 4 is turned on, the water pump of the third heat exchanger 5 is turned on, and if a first solenoid valve S1 is provided between the inlet and outlet of the third heat exchanger 5, the first solenoid valve S1 is closed, and the fan of the first heat exchanger 3 is turned on;

[0143] If the target operation mode is cooling + domestic hot water mode or heating + domestic hot water mode, the water pump or fan of the second heat exchanger 4 is turned on, the water pump of the third heat exchanger 5 is turned on, and if a first solenoid valve S1 is provided between the inlet and outlet of the third heat exchanger 5, the first solenoid valve S1 is closed;

[0144] Specifically, if the second heat exchanger 4 is a water-cooled heat exchanger, then its water pump is operated accordingly; if the second heat exchanger 4 is an air-cooled heat exchanger, then its fan is operated accordingly; if the third heat exchanger 5 is a water-cooled heat exchanger, then its water pump is operated.

[0145] When switching the operation mode, the four-way reversing valve 2 needs to be controlled to switch to the flow direction of the corresponding mode.

[0146] In step S2, according to the refrigerant flow direction preset in the target operation mode, the drive mechanism and / or valve on the corresponding heat exchanger side is controlled to perform operation or closing action, including:

[0147] According to the preset refrigerant flow direction in heating mode, if ST-CT>D3, the unit will be controlled as follows:

[0148] The first solenoid valve S1 is opened, the fifth solenoid valve S5 is closed, and the fourth solenoid valve S4 is opened. After a preset time, when the refrigerant outlet temperature of the third heat exchanger 5 is higher than the condensing temperature, the temperature before the throttling mechanism 7, the outlet water temperature of the second heat exchanger 4, or the outlet air temperature of the second heat exchanger 4, the fourth solenoid valve S4 is closed;

[0149] Until ST-CT<D4, the fifth solenoid valve S5 is opened;

[0150] Among them, ST represents the target temperature value of any temperature among the return water temperature, the outlet water temperature, the return air temperature or the outlet air temperature, CT represents the return water temperature, the outlet water temperature, the return air temperature or the outlet air temperature corresponding to the target temperature value, D3 represents the third deviation value, and D4 represents the fourth deviation value.

[0151] Based on the above disclosed content, this embodiment determines the target operating mode on the user demand side according to the functional relationship between the temperature detection value of the current operating mode and the target temperature value; according to the refrigerant flow direction preset in the target operating mode, the drive mechanism and / or valve on the corresponding heat exchanger side is controlled to operate or close, so that the unit operates in the target operating mode, thereby realizing effective control of the multi-functional unit, providing users with a variety of operating modes, and meeting the diversified usage needs of users.

[0152] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A control method for a multifunctional air conditioning unit, characterized in that: The multi-functional air conditioner unit includes a compressor (1), a four-way reversing valve (2), a first heat exchanger (3), a second heat exchanger (4), a third heat exchanger (5), a one-way control valve assembly (6), and a throttling mechanism (7); The exhaust port (1a) and the suction port (1b) of the compressor (1) are connected to the four-way reversing valve (2). The four-way reversing valve (2) is respectively communicated with the inlet of the first heat exchanger (3) and the first connection port (41) of the second heat exchanger (4). The outlet of the first heat exchanger (3) and the second connection port (42) of the second heat exchanger (4) are respectively communicated with the one-way control valve assembly (6). The one-way control valve assembly (6) is communicated with the inlet and the outlet of the third heat exchanger (5). The throttling mechanism (7) is arranged between the one-way control valve assembly (6) and the outlet of the third heat exchanger (5); The one-way control valve assembly (6) includes a first control valve C1, a second control valve C2, a third control valve C3, and a fourth control valve C4. One end of the first control valve C1 and one end of the fourth control valve C4 are respectively communicated with the outlet of the first heat exchanger (3). The other end of the first control valve C1 and one end of the second control valve C2 are respectively communicated with the inlet of the third heat exchanger (5). The other end of the second control valve C2 is communicated with the second connection port (42) of the second heat exchanger (4). Both ends of the third control valve C3 are respectively communicated with the other end of the fourth control valve C4 and the other end of the second control valve C2. The other end of the fourth control valve C4 is communicated with the throttling mechanism (7); The control method includes: Judging the target operation mode on the user demand side according to the functional relationship between the temperature detection value and the target temperature value of the current operation mode; Controlling the driving mechanism and / or the valve on the corresponding heat exchanger side to operate or close according to the refrigerant flow direction preset by the target operation mode, so that the unit operates in the target operation mode; Wherein, the types of the temperature detection value and the target temperature value both at least include the return water temperature, the return air temperature, the outlet water temperature, the outlet air temperature, the water tank temperature, and / or the ambient temperature. The user demand side at least includes the user's refrigeration side, heating side, and / or domestic hot water side; The target operation mode includes a basic operation mode, a semi-automatic mode, and / or a full-automatic operation mode. The basic operation mode includes a refrigeration mode, a heating mode, a domestic hot water mode, a refrigeration + domestic hot water mode, and / or a heating + domestic hot water mode selected by the user. The semi-automatic mode includes an automatic refrigeration + domestic hot water mode and / or an automatic heating + domestic hot water mode. The full-automatic operation mode is an operation mode in which the unit adaptively and automatically switches the basic operation mode according to the user settings and the environmental conditions; If the current operation mode is the automatic refrigeration + domestic hot water mode, judging the target operation mode on the user demand side according to the functional relationship between the temperature detection value and the target temperature value of the current operation mode, including: 1) If HCT < ST1 - D1 and SHT1 < SHCT - D2, it is determined that the target operation mode on the user demand side is the domestic hot water mode; 2) If HCT > ST1 + D1 and SHT1 < SHCT - D2, then it is determined that the target operation mode on the user demand side is the cooling + domestic hot water mode; 3) If HCT > ST1 + D1 and SHT1 > SHCT + D2, then it is determined that the target operation mode on the user demand side is the cooling mode; Wherein, HCT represents the currently detected return water temperature, ST1 represents the target return water temperature on the cooling side, SHT1 represents the target temperature required on the domestic hot water side, SHCT represents the detected temperature, and D1 and D2 respectively represent the first preset deviation value and the second preset deviation value.

2. The control method of the multifunctional air conditioning unit according to claim 1, characterized in that: A first bypass (8) is provided between the inlet and the outlet of the third heat exchanger (5), and a first solenoid valve S1 is provided on the first bypass (8).

3. The control method of the multifunctional air conditioning unit according to claim 1 or 2, characterized in that: The third heat exchanger (5) includes a first heat exchange component and a second heat exchange component. The first heat exchange component is provided with a first inlet (51) and a first outlet (52), and the second heat exchange component is provided with a second inlet (53) and a second outlet (54); The other end of the first control valve C1 and one end of the second control valve C2 are respectively communicated with the first inlet (51), and the throttling mechanism (7) is communicated with the first outlet (52); The exhaust port (1a) of the compressor (1) is directly communicated with the second inlet (53), or the exhaust port (1a) of the compressor (1) is communicated with the second inlet (53) after passing through the four-way reversing valve (2), and the four-way reversing valve (2) is communicated with the second outlet (54).

4. The control method of the multifunctional air conditioning unit according to claim 3, characterized in that: When the exhaust port (1a) of the compressor (1) is directly communicated with the second inlet (53), a first passage (9) is provided between the exhaust port (1a) of the compressor (1) and the second inlet (53), a second passage (10) is provided between the four-way reversing valve (2) and the second outlet (54), a third passage (11) is provided between the first passage (9) and the second passage (10), and a second solenoid valve S2 is provided on the third passage (11).

5. The control method of the multifunctional air conditioning unit according to claim 3, characterized in that: When the exhaust port (1a) of the compressor (1) is communicated with the second inlet (53) after passing through the four-way reversing valve (2), the four-way reversing valve (2) is provided with a fourth passage (12), the fourth passage (12) is provided with a first branch (121) and a second branch (122), the first branch (121) is communicated with the second inlet (53), the second branch (122) is communicated with the second outlet (54), and a third solenoid valve S3 is provided at a point near the branch point of the two branches on the second branch (122).

6. The control method of the multifunctional air conditioning unit according to claim 2, characterized in that: A second bypass (13) is provided on the connecting pipeline between the four-way reversing valve (2) and the first heat exchanger (3), or the second bypass (13) is provided on the connecting pipeline between the exhaust port (1a) of the compressor (1) and the four-way reversing valve (2), a fourth solenoid valve S4 is provided on the second bypass (13), a fifth solenoid valve S5 is provided on the connecting pipeline between one end of the first bypass (8) and the inlet of the third heat exchanger (5), and one end of the second bypass (13) is connected to the connecting pipeline between the fifth solenoid valve S5 and the inlet of the third heat exchanger (5).

7. The control method of the multifunctional air conditioning unit according to claim 1, characterized in that: The first heat exchanger (3) comprises an air-cooled heat exchanger or an evaporative condenser, the second heat exchanger (4) comprises a water-cooled heat exchanger or an air-cooled heat exchanger, and / or the third heat exchanger (5) comprises a water-cooled heat exchanger or a water exchange tank.

8. The control method of the multifunctional air conditioning unit according to claim 3, characterized in that: The third heat exchanger (5) comprises a first heat exchange tank and a second heat exchange tank, wherein the second heat exchange tank is arranged below the first heat exchange tank.

9. The control method of the multifunctional air conditioning unit according to claim 1, characterized in that: Control the operation or shutdown of the drive mechanism and / or valve on the corresponding heat exchanger side, including: If the target operation mode is cooling or heating mode, the water pump or fan of the second heat exchanger (4) is turned on, the water pump of the third heat exchanger (5) is turned off or not operated, and if a first solenoid valve S1 is provided between the inlet and outlet of the third heat exchanger (5), the first solenoid valve S1 is turned on; If the target operation mode is the domestic hot water mode, the water pump or fan of the second heat exchanger (4) is turned on, the water pump of the third heat exchanger (5) is turned on, and if a first solenoid valve S1 is provided between the inlet and outlet of the third heat exchanger (5), the first solenoid valve S1 is closed, and the fan of the first heat exchanger (3) is turned on; If the target operation mode is cooling + domestic hot water mode or heating + domestic hot water mode, the water pump or fan of the second heat exchanger (4) is turned on, the water pump of the third heat exchanger (5) is turned on, and if a first solenoid valve S1 is provided between the inlet and outlet of the third heat exchanger (5), the first solenoid valve S1 is closed; When switching the operating mode, the four-way reversing valve (2) needs to be controlled to switch to the flow direction of the corresponding mode.

10. The control method of the multifunctional air conditioning unit according to claim 9, characterized in that: If the current operation mode is the automatic cooling + domestic hot water mode, the target operation mode on the user demand side is determined according to the functional relationship between the temperature detection value of the current operation mode and the target temperature value, including: The temperature detection value of the current operating mode and the target temperature value are weighted to obtain the first target mode determination value F1, and the calculation formula is as follows: F1=a1*(HCT-ST1)+b1*(SHT1-SHCT); or F1=a1*(HCT-ST1)+b1*(SHT1-SHCT)+c1*AT; or F1=a1*(HCT-ST1)+b1*(SHT1-SHCT)+c1*AT+d*(HCT-ST1)*(SHT1-SHCT)+e1*(SHT1-SHCT)*AT+f1*(HCT-ST1)*AT; Wherein, AT represents the ambient temperature, a1, b1, c1, d1, e1 and f1 represent the first weighting coefficient; According to the value of the first target mode determination value F1, the target operation mode of the user demand side is determined as follows: If the value of F1 is between FF1 and FF2, the target operation mode is determined to be the domestic hot water mode; If the value of F1 is between FF3 and FF4, the target operation mode is determined to be cooling + domestic hot water mode; If the value of F1 is between FF5 and FF6, the target operation mode is determined to be cooling mode; Among them, FF1, FF2, FF3, FF4, FF5, and FF6 all represent preset target operating mode judgment values, and the values ​​increase in sequence.

11. The control method of the multifunctional air conditioning unit according to claim 10, characterized in that: If the current operation mode is the fully automatic operation mode, the target operation mode on the user demand side is determined according to the functional relationship between the temperature detection value of the current operation mode and the target temperature value, including: According to the value of the second target mode determination value F2, the target operation mode of the user demand side is determined as follows: F2 = a2*(HCT-ST1)+b2*(SHT1-SHCT)+c2*AT; or F2=a2*(HCT-ST1)+b2*(SHT1-SHCT)+c2*AT +d2*(HCT-ST1)*(SHT1-SHCT)+e2*(SHT1-SHCT)*AT +f2*(SHT1-SHCT)*AT+g2*(HCT-ST1)*(SHT1-SHCT)*AT; Wherein, a2, b2, c2, d2, e2, f2 and g2 all represent the second weighting coefficient; If the value of F2 is between FF1 and FF2, the target operation mode is determined to be the domestic hot water mode; If the value of F2 is between FF3 and FF4, the target operation mode is determined to be cooling + domestic hot water mode; If the value of F2 is between FF5 and FF6, the target operation mode is determined to be cooling mode; If the value of F2 is between FF7 and FF8, the target operation mode is determined to be heating mode; If the value of F2 is between FF9 and FF10, the target operation mode is determined to be heating + domestic hot water mode; Among them, FF1, FF2, FF3, FF4, FF5, FF6, FF7, FF8, FF9 and FF10 all represent preset target operating mode judgment values, and the values ​​increase in sequence.

12. The control method of the multifunctional air conditioning unit according to claim 1, characterized in that: According to the refrigerant flow direction preset in the target operation mode, the drive mechanism and / or valve on the corresponding heat exchanger side is controlled to perform operation or closing action, including: According to the preset refrigerant flow direction in heating mode, if ST-CT>D3, the unit will be controlled as follows: The first solenoid valve S1 is opened, the fifth solenoid valve S5 is closed and the fourth solenoid valve S4 is opened. After a preset time, when the refrigerant outlet temperature of the third heat exchanger (5) is higher than the condensing temperature, the temperature before the throttling mechanism (7), the outlet water temperature of the second heat exchanger (4) or the outlet air temperature of the second heat exchanger (4), the fourth solenoid valve S4 is closed; Until ST-CT<D4, the fifth solenoid valve S5 is opened; Among them, ST represents the target temperature value of any temperature among the return water temperature, the outlet water temperature, the return air temperature or the outlet air temperature, CT represents the return water temperature, the outlet water temperature, the return air temperature or the outlet air temperature corresponding to the target temperature value, D3 represents the third deviation value, and D4 represents the fourth deviation value.

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