A refrigeration system, its control method and an air conditioner

Abstract

The present invention provides a refrigeration system, a control method thereof, and an air conditioner. The refrigeration system includes: a compressor, an outdoor heat exchanger, a first indoor heat exchanger, a second indoor heat exchanger, a first throttling device, and a second throttling device; an active adjustment device is arranged between the first throttling device and the first indoor heat exchanger, and the active adjustment device can store refrigerant therein. The active adjustment device can store different amounts of refrigerant according to different operating modes. When the refrigeration system operates in the refrigeration mode, the volume of the refrigerant stored in the active adjustment device is V1. When the refrigeration system operates in the reheating and dehumidifying mode, the volume of the refrigerant stored in the active adjustment device is V2, and V2 > V1 ≥ 0. According to the present invention, the problem of the charging amount deviation in different operating modes is effectively solved, the reheating and dehumidifying SMER, the dehumidifying capacity, and the indoor air outlet temperature of the system are effectively improved, and the purpose of improving the user comfort while saving energy is achieved.

Description

Technical Field

[0001] The present invention relates to the field of refrigeration technology, and particularly to a refrigeration system, a control method thereof, and an air conditioner. Background Art

[0002] As a device for adjusting environmental comfort, the function of the air-conditioning system has developed from a single temperature adjustment to a more diversified one to meet the ever-increasing demand for the comfort of the living environment of people.

[0003] The dehumidification technology of the air-conditioning system mainly adopts refrigeration dehumidification, that is, the surface temperature of the indoor heat exchanger is lowered below the dew point temperature of the air. When the indoor air flows through the surface of the heat exchanger, the water vapor in the air will condense, removing the moisture in the air. This method is suitable for high-temperature environments and can complete indoor cooling while dehumidifying. However, during the "plum rain season" in the Yangtze River Basin or the "returning south day" in South China, when the temperature is not high but the relative humidity is relatively high, refrigeration dehumidification will lead to a deterioration in the comfort of the living environment due to the too low outlet air temperature.

[0004] To solve the above problems, the method of reheating dehumidification is adopted to heat and raise the temperature of the dehumidified air to maintain the comfort of the living environment. The conventional reheating dehumidification method uses electric heating, but this method consumes a large amount of electricity, and the air flow will be unevenly heated. In addition, some researchers have proposed to add a reheating dehumidification function to the air-conditioning wall-mounted machine.

[0005] Publication No. CN106799117A proposes a dehumidification device, which has a reheating dehumidification function to ensure that the temperature does not drop during dehumidification in the transition season and improve indoor comfort. However, when this device is applied to an air conditioner, there are problems such as a large difference in refrigerant charging in different modes, poor dehumidification energy efficiency, and a narrow temperature adjustment range.

[0006] Publication No. CN115789791A proposes an air-conditioning system, which can solve the problem of large differences in refrigerant charging amounts in the refrigeration and reheating dehumidification modes and poor system energy efficiency to a certain extent. However, there is a deviation in the optimal refrigerant charging amounts in the refrigeration and heating modes of this system, and there is a problem that the system performance is not optimal. In addition, when the external fan stops rotating in the reheating dehumidification mode of this system, the system refrigerant charging amount cannot be adjusted, and the dehumidification energy efficiency is poor.

[0007] Due to the large differences in refrigerant charging amounts in the refrigeration, heating, and reheating dehumidification modes of the series reheating dehumidification system in the prior art, there are technical problems such as refrigerant surplus or shortage in the system during operation in different modes, and it is impossible to improve user comfort while saving energy. Therefore, the present invention researches and designs a refrigeration system, a control method thereof, and an air conditioner. Summary of the Invention

[0008] Therefore, the technical problem to be solved by the present invention is to overcome the defect that there are large differences in the refrigerant filling amounts in the refrigeration, heating, and reheating and dehumidification modes of the existing reheating and dehumidification system, and there is refrigerant surplus or shortage in the system during operation in different modes, resulting in the inability to improve user comfort while saving energy. Thus, a refrigeration system, its control method, and an air conditioner are provided.

[0009] To solve the above problems, the present invention provides a refrigeration system, which includes:

[0010] A compressor, an outdoor heat exchanger, an indoor first heat exchanger, an indoor second heat exchanger, a first throttling device, and a second throttling device. Along the direction of refrigerant flow, the compressor, the outdoor heat exchanger, the first throttling device, the indoor first heat exchanger, the second throttling device, and the indoor second heat exchanger can be directly or indirectly connected in sequence to form a refrigeration cycle loop;

[0011] The refrigeration system further includes an active adjustment device, which is arranged between the first throttling device and the indoor first heat exchanger, and the active adjustment device can store refrigerant therein. The active adjustment device can store different amounts of refrigerant according to different operating modes. When the refrigeration system operates in the refrigeration mode, the volume of the refrigerant stored in the active adjustment device is V1. When the refrigeration system operates in the reheating and dehumidification mode, the volume of the refrigerant stored in the active adjustment device is V2, and V2 > V1 ≥ 0.

[0012] In some embodiments,

[0013] It further includes a four-way reversing valve, and the four ends of the four-way reversing valve are respectively connected to the outlet of the compressor, the inlet of the compressor, one end of the outdoor heat exchanger, and one end of the indoor second heat exchanger;

[0014] Along the direction of refrigerant flow, the compressor, the indoor second heat exchanger, the second throttling device, the indoor first heat exchanger, the active adjustment device, the first throttling device, and the outdoor heat exchanger can be directly or indirectly connected in sequence, that is, a heating cycle loop can also be formed; when the refrigeration system operates in the heating mode, the volume of the refrigerant stored in the active adjustment device is V3, and V3 ≥ V1 ≥ 0.

[0015] In some embodiments,

[0016] The active adjustment device is a container with a hollow interior, having a first port, a second port, and a third port. The first port, the second port, and the third port can respectively connect the interior of the container to the exterior. The first port is connected to one end of the first throttling device through a first pipeline. The second port is connected to one end of the first indoor heat exchanger through a second pipeline. A first control valve is provided on the second pipeline. The third port is connected to the second pipeline through a third pipeline and is located at a position between the first control valve and the first indoor heat exchanger. A second control valve is also provided on the third pipeline;

[0017] When the refrigeration system operates in the refrigeration mode, the first control valve is opened, the second control valve is closed, the first port is the refrigerant inlet, the second port is the refrigerant outlet, and the third port is blocked. When the refrigeration system operates in the reheating and dehumidifying mode, the first control valve is closed, the second control valve is opened, the first port is the refrigerant inlet, the second port is blocked, and the third port is the refrigerant outlet.

[0018] In some embodiments,

[0019] The active adjustment device is arranged vertically up and down. The first port is located at the upper end of the active adjustment device, the second port is located at the lower end of the active adjustment device, the third port is provided on the side of the active adjustment device, and the height of the third port is higher than that of the second port and equal to or lower than that of the first port.

[0020] In some embodiments,

[0021] The height of the active adjustment device is H, that is, the vertical height from the upper end to the lower end of the active adjustment device is H. The height of the third port is h_1, that is, the vertical height from the third port to the lower end of the active adjustment device is h_1;

[0022] When the refrigeration system operates in the refrigeration mode, the height of the refrigerant stored in the active adjustment device Δh = 0. When the refrigeration system operates in the reheating and dehumidifying mode, the height of the refrigerant stored in the active adjustment device Δh = h_1.

[0023] In some embodiments,

[0024] When the refrigeration system operates in the heating mode, the first control valve is opened, the second control valve is closed or opened, the first port is the refrigerant outlet, the second port is the refrigerant inlet, the third port is blocked or is also the refrigerant inlet; the height of the refrigerant stored in the active adjustment device Δh = H.

[0025] In some embodiments,

[0026] The refrigeration system is a series reheat dehumidification system. The optimal refrigerant charges for its refrigeration, heating, and reheat dehumidification modes are m_1, m_2, and m_3 respectively. The internal volume of the active regulating device is ΔV, and the inner diameter is d. The dimensions of the active regulating device satisfy the following relationship:

[0027] When (m_1 - m_2) > (m_1 - m_3), ΔV = (m_1 - m_2) / ρ_1 = (πd^2) / 4 * H;

[0028] Where ρ_1 is the density of the saturated liquid refrigerant corresponding to the condensation temperature in the heating mode;

[0029] And: (m_1 - m_3) / ρ_2 = (πd^2) / 4 * h_1;

[0030] Where ρ_2 is the density of the saturated liquid refrigerant corresponding to the condensation temperature in the reheat dehumidification mode.

[0031] In some embodiments,

[0032] The refrigeration system is a series reheat dehumidification system. The optimal refrigerant charges for its refrigeration, heating, and reheat dehumidification modes are m_1, m_2, and m_3 respectively. The internal volume of the active regulating device is ΔV, and the inner diameter is d. The dimensions of the active regulating device satisfy the following relationship:

[0033] When (m_1 - m_2) ≤ (m_1 - m_3), h_1 = H,

[0034] If designed optimally according to the heating mode, then: ΔV = (m_1 - m_2) / ρ_1 = (πd^2) / 4 * H;

[0035] Where ρ_1 is the density of the saturated liquid refrigerant corresponding to the condensation temperature in the heating mode;

[0036] If designed optimally according to the reheat dehumidification mode, then: ΔV = (m_1 - m_3) / ρ_2 = (πd^2) / 4 * H;

[0037] Where ρ_2 is the density of the saturated liquid corresponding to the condensation temperature in the reheat dehumidification mode.

[0038] In some embodiments,

[0039] When the refrigeration system is a single - cooling system, the optimal refrigerant charges for its refrigeration and reheat dehumidification modes are m_1 and m_3 respectively. The internal volume of the active regulating device is ΔV. The internal volume of the active regulating device is ΔV, and the inner diameter is d. The dimensions of the active regulating device satisfy the following relationship:

[0040] ΔV = (m_1 - m_3) / ρ_2 = (πd^2) / 4 * h_1; where ρ_2 is the refrigerant saturated liquid density corresponding to the condensation temperature during reheating and dehumidification.

[0041] When operating in the reheating and dehumidifying mode, the liquid level height of the active regulating device is the same as the opening height of the third port, i.e., h_1 = Δh ≤ H.

[0042] In some embodiments,

[0043] In the reheating and dehumidifying mode, the opening degree of the second throttling device is controlled by the superheat T_SH at the outlet of the indoor second heat exchanger; if T_SH > T_2, control the opening degree of the second throttling device to increase; if T_SH < T_1, control the opening degree of the second throttling device to decrease; if T_1 < T_SH < T_2, control the opening degree of the second throttling device to remain unchanged; where T_1 and T_2 are both preset temperature values, and 0 < T_1 < T_2.

[0044] In some embodiments,

[0045] It further includes an outdoor fan and an indoor fan. The outdoor fan can drive the air flow to exchange heat with the outdoor heat exchanger, and the indoor fan can drive the air flow to exchange heat with the indoor first heat exchanger and the indoor second heat exchanger.

[0046] When T_1 < T_SH < T_2, the rotational speed of the outdoor fan is controlled according to the indoor return air temperature T_in: when T_in < T_set - Δt, control the rotational speed of the outdoor fan to decrease; when T_in > T_set + Δt, control the rotational speed of the outdoor fan to increase; when T_set - Δt < T_in < T_set + Δt, control the rotational speed of the outdoor fan to remain unchanged; where T_set is a preset temperature value and Δt is a preset temperature difference.

[0047] The present invention also provides a control method for a refrigeration system as described above, which includes:

[0048] A detection step of detecting the operating mode of the refrigeration system.

[0049] A judgment step of judging whether the operating mode is a refrigeration mode or a reheating and dehumidifying mode.

[0050] A control step of, when the refrigeration system operates in the refrigeration mode, controlling the first control valve to open and the second control valve to close; when the refrigeration system operates in the reheating and dehumidifying mode, controlling the first control valve to close and the second control valve to open.

[0051] In some embodiments,

[0052] When the refrigeration system further includes a four-way reversing valve:

[0053] In the determination step, it is determined whether the operating mode is a refrigeration mode, a heating mode, or a reheating and dehumidification mode;

[0054] In the control step, when the refrigeration system operates in the heating mode, the first control valve is controlled to open, and the second control valve is controlled to close or open.

[0055] In some embodiments,

[0056] When the refrigeration system operates in the reheating and dehumidification mode:

[0057] In the detection step, the intermediate saturation temperature and the outlet temperature of the indoor second heat exchanger are further detected to calculate the outlet superheat degree T_SH;

[0058] In the determination step, the relationships between T_SH and T_1 and T_2 are respectively determined, where T_1 and T_2 are both temperature preset values, and 0 < T_1 < T_2;

[0059] In the control step, if T_SH > T_2, the opening degree of the second throttling device is controlled to increase; if T_SH < T_1, the opening degree of the second throttling device is controlled to decrease; if T_1 < T_SH < T_2, the opening degree of the second throttling device is controlled to remain unchanged.

[0060] In some embodiments,

[0061] When there are also an outdoor fan and an indoor fan and T_1 < T_SH < T_2:

[0062] In the detection step, the return air temperature T_in of the room is further detected;

[0063] In the determination step, the relationships between T_in and T_set - Δt and T_set + Δt are respectively determined, where T_set is a temperature preset value and Δt is a preset temperature difference;

[0064] In the control step, when T_in < T_set - Δt, the rotational speed of the outdoor fan is controlled to decrease; when T_in > T_set + Δt, the rotational speed of the outdoor fan is controlled to increase; when T_set - Δt < T_in < T_set + Δt, the rotational speed of the outdoor fan is controlled to remain unchanged.

[0065] The present invention further provides an air conditioner, which includes the aforementioned refrigeration system.

[0066] A refrigeration system, its control method, and an air conditioner provided by the present invention have the following beneficial effects:

[0067] 1. The present invention is provided with an active adjustment device between the first throttling device of the refrigeration system and the first indoor heat exchanger. The active adjustment device can store different amounts of refrigerant according to different operating modes. In particular, the volume V1 of the refrigerant stored in the refrigeration mode is less than the volume V2 of the refrigerant stored in the reheating and dehumidifying mode. Since the outdoor fan speed is lower and the outdoor refrigerant heat exchange amount is smaller in the reheating and dehumidifying mode than in the refrigeration mode, the amount of refrigerant required to operate in the system in the reheating and dehumidifying mode is less than that in the refrigeration mode. Therefore, through the storage function of the active adjustment device, the excess liquid refrigerant in the reheating and dehumidifying mode is effectively stored, avoiding the situation of excessive refrigerant amount operating in the system in the reheating and dehumidifying mode. After the excess refrigerant is stored in the refrigerant adjustment device, the subcooling degree of the reheating heat exchanger decreases, the exhaust pressure decreases, the pressure ratio decreases, and the system SMER is improved, effectively increasing the dehumidification amount per unit energy consumption (SMER). And it ensures a sufficient amount of refrigerant in the refrigeration mode to ensure normal cooling capacity and cooling comfort, avoiding the situation of insufficient refrigerant. Therefore, the present invention effectively solves the problem of charging amount deviation in different operating modes, effectively improves the reheating and dehumidifying SMER, dehumidification amount and indoor air outlet temperature of the system, achieving the purpose of improving user comfort while saving energy.

[0068] 2. The present invention is applicable to refrigeration systems with single cooling and reheating and dehumidifying functions, and can also be applied to systems with refrigeration, heating and reheating and dehumidifying functions. By setting the volume V3 stored in the active adjustment device in the heating mode to be greater than the volume V1 of the refrigerant stored in the refrigeration mode, since the optimal charging difference between refrigeration and heating is mainly related to the volume ratio of the indoor and outdoor heat exchangers. Usually, the volume of the outdoor heat exchanger is larger than that of the indoor heat exchanger, and the dryness of the refrigerant in the condenser is lower than that in the evaporator. At the same volume, the condenser stores more refrigerant. Therefore, the refrigerant charging amount in the refrigeration mode is greater than that in the heating mode, which can effectively reduce the amount of refrigerant in the system in the heating mode, avoid refrigerant surplus, and at the same time increase and ensure the amount of refrigerant in the system in the refrigeration mode, avoiding the situation of insufficient refrigerant in the refrigeration mode. Therefore, the present invention effectively solves the problem of charging amount deviation in different operating modes, effectively improves the heating COP, reheating and dehumidifying SMER, dehumidification amount and indoor air outlet temperature of the system, achieving the purpose of improving user comfort while saving energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 is the system cycle structure diagram in the refrigeration mode of the main embodiment of the refrigeration system of the present invention;

[0070] Figure 2 is the system cycle structure diagram in the heating mode of the main embodiment of the refrigeration system of the present invention;

[0071] Figure 3 is the system cycle structure diagram in the reheating and dehumidifying mode of the main embodiment of the refrigeration system of the present invention;

[0072] Figure 4 It is the system cycle structure diagram in the refrigeration mode of an alternative embodiment of the refrigeration system of the present invention;

[0073] Figure 5 It is the system cycle structure diagram in the reheating and dehumidifying mode of an alternative embodiment of the refrigeration system of the present invention;

[0074] Figure 6a It is the device structure diagram of the active adjustment device of the refrigeration system of the present invention in the refrigeration mode;

[0075] Figure 6b It is the device structure diagram of the active adjustment device of the refrigeration system of the present invention in the heating mode;

[0076] Figure 6c It is the device structure diagram of the active adjustment device of the refrigeration system of the present invention in the reheating and dehumidifying mode;

[0077] Figure 7 It is the control flow chart of the refrigeration system of the present invention in the heating and dehumidifying mode.

[0078] The reference numerals are as follows:

[0079] 1. Compressor; 2. Four-way reversing valve; 3a. Outdoor heat exchanger; 3b. Indoor first heat exchanger; 3c. Indoor second heat exchanger; 4a. First throttling device; 4b. Second throttling device; 5a. Outdoor fan; 5b. Indoor fan; 6. Active adjustment device; 6a. First port; 6b. Second port; 6c. Third port; 101. First pipeline; 102. Second pipeline; 103. Third pipeline. Detailed implementation manners

[0080] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way limits the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0081] It should be noted that the terms used here are only for describing the specific implementation manners and are not intended to limit the exemplary implementation manners according to the present application. As used here, unless otherwise clearly specified in the context, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or their combinations.

[0082] Unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for the sake of convenience of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the said technologies, methods, and devices should be regarded as part of the authorization specification. In all the examples shown and discussed here, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0083] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by orientation terms such as "front, rear, upper, lower, left, right", "lateral, vertical, perpendicular, horizontal", and "top, bottom", etc. are generally based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description. Without contrary statements, these orientation terms do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and thus should not be construed as limiting the protection scope of the present invention; the orientation terms "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0084] For the convenience of description, spatial relative terms such as "above...", "over...", "on the upper surface of...", "above" etc. may be used here to describe the spatial positional relationships between a device or feature shown in the drawings and other devices or features. It should be understood that the spatial relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the drawings for the device. For example, if the device in the drawing is inverted, the device described as "above other devices or structures" or "over other devices or structures" will then be positioned "below other devices or structures" or "under other devices or structures". Thus, the exemplary term "above..." can include both the orientations of "above..." and "below...". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and corresponding interpretations should be made for the spatial relative descriptions used here.

[0085] In addition, it should be noted that the use of words such as "first", "second", etc. to limit components is only for the convenience of distinguishing the corresponding components. Without otherwise stating, the above words have no special meanings, and thus should not be construed as limiting the protection scope of the present invention.

[0086] As shown Figure 1-7 in the figure, the present invention provides a refrigeration system, which includes:

[0087] a compressor 1, an outdoor heat exchanger 3a, a first indoor heat exchanger 3b, a second indoor heat exchanger 3c, a first throttling device 4a and a second throttling device 4b. Along the refrigerant flow direction, the compressor 1, the outdoor heat exchanger 3a, the first throttling device 4a, the first indoor heat exchanger 3b, the second throttling device 4b and the second indoor heat exchanger 3c can be directly or indirectly connected in sequence to form a refrigeration cycle loop;

[0088] The refrigeration system further includes an active adjustment device 6. The active adjustment device 6 is arranged between the first throttling device 4a and the first indoor heat exchanger 3b, and the active adjustment device 6 can store refrigerant therein. The active adjustment device 6 can store different amounts of refrigerant according to different operating modes. When the refrigeration system operates in the refrigeration mode, the volume of the refrigerant stored in the active adjustment device 6 is V1. When the refrigeration system operates in the reheat dehumidification mode, the volume of the refrigerant stored in the active adjustment device 6 is V2, and V2 > V1 ≥ 0.

[0089] By arranging the active adjustment device between the first throttling device and the first indoor heat exchanger of the refrigeration system, and the active adjustment device can store different amounts of refrigerant according to different operating modes. Especially, the volume of the refrigerant stored in the refrigeration mode V1 is less than the volume of the refrigerant stored in the reheat dehumidification mode V2. Since the outdoor fan speed is lower in the reheat dehumidification mode than in the refrigeration mode, the outdoor refrigerant heat exchange amount is smaller in the reheat dehumidification mode than in the refrigeration mode, and the amount of refrigerant required to operate in the system in the reheat dehumidification mode is less than that in the refrigeration mode. Therefore, through the storage function of the active adjustment device, the excess liquid refrigerant in the reheat dehumidification mode is effectively stored, avoiding the situation of excessive refrigerant amount operating in the system in the reheat dehumidification mode. After the excess refrigerant is stored in the refrigerant adjustment device, the subcooling degree of the reheat heat exchanger is reduced, the exhaust pressure is reduced, the pressure ratio is reduced, and the system SMER is improved, effectively improving the specific moisture extraction ratio (SMER) of unit energy consumption, and ensuring a sufficient amount of refrigerant in the refrigeration mode to ensure normal refrigeration capacity and refrigeration comfort, avoiding the situation of insufficient refrigerant. Therefore, the present invention effectively solves the problem of charging amount deviation in different operating modes, effectively improves the reheat dehumidification SMER, dehumidification amount and indoor air outlet temperature of the system, and achieves the purpose of improving user comfort while saving energy.

[0090] The present invention proposes an active adjustment reheat dehumidification scheme for the charging amount, which can effectively solve the problem of charging amount deviation in different operating modes, improve the system heating COP, reheat dehumidification SMER, dehumidification amount and indoor air outlet temperature, and achieve the purpose of improving user comfort while saving energy.

[0091] 1. It can effectively solve the problem that there are large differences in the refrigerant charge amounts in the refrigeration, heating, and reheating dehumidification modes of the existing series reheat dehumidification system, and there is an excess or shortage of refrigerant in the system during operation in different modes.

[0092] 2. It can also effectively solve the problem that there is an excessive amount of refrigerant in the reheating dehumidification mode, with a large degree of subcooling, a high condensing temperature, poor dehumidification energy efficiency. When operating at the highest outlet air temperature for dehumidification and the maximum dehumidification capacity at a constant temperature, restricted by the excessively high exhaust pressure and temperature, the compressor frequency cannot be increased, and the highest outlet air temperature and the maximum dehumidification capacity cannot be increased.

[0093] 3. It can also effectively solve the problem that in the transitional season when the temperature is not high and the relative humidity is high in a conventional refrigeration system, the outlet air temperature is low and the comfort is poor during dehumidification.

[0094] In some embodiments,

[0095] It further includes a four-way reversing valve 2, and the four ends of the four-way reversing valve 2 are respectively connected to the outlet of the compressor 1, the inlet of the compressor 1, one end of the outdoor heat exchanger 3a, and one end of the indoor second heat exchanger 3c.

[0096] Along the direction of refrigerant flow, the compressor 1, the indoor second heat exchanger 3c, the second throttling device 4b, the indoor first heat exchanger 3b, the active regulating device 6, the first throttling device 4a, and the outdoor heat exchanger 3a can be directly or indirectly connected in sequence, that is, a heating cycle circuit can also be formed; when the refrigeration system operates in the heating mode, the volume of refrigerant stored in the active regulating device 6 is V3, and V3≥V1≥0.

[0097] The present invention is applicable to a refrigeration system for single cooling and reheating dehumidification, and can also be applicable to a system for refrigeration, heating, and reheating dehumidification. By setting the volume V3 stored in the active regulating device in the heating mode to be greater than the volume of refrigerant stored in the refrigeration mode V1, since the optimal charge difference between refrigeration and heating is mainly related to the volume ratio of the indoor and outdoor heat exchangers, usually the volume of the outdoor heat exchanger is larger than that of the indoor heat exchanger, and the dryness of the refrigerant in the condenser is lower than that in the evaporator. At the same volume, the condenser stores more refrigerant. Therefore, the refrigerant charge in the refrigeration mode is greater than that in the heating mode, which can effectively reduce the amount of refrigerant in the system in the heating mode, avoid refrigerant excess, and at the same time increase and ensure the amount of refrigerant in the system in the refrigeration mode, avoid the situation of refrigerant shortage in the refrigeration mode. Therefore, the present invention effectively solves the problem of the deviation of the charge amount in different operating modes, effectively improves the system heating COP, reheating dehumidification SMER, dehumidification capacity, and indoor outlet air temperature, and achieves the purpose of improving user comfort while saving energy.

[0098] In some embodiments,

[0099] The active adjustment device 6 is a hollow container having a first port 6a, a second port 6b, and a third port 6c. The first port 6a, the second port 6b, and the third port 6c can respectively connect the interior of the container to the exterior. The first port 6a is connected to one end of the first throttling device 4a through a first pipeline 101. The second port 6b is connected to one end of the first indoor heat exchanger 3b through a second pipeline 102. A first control valve 4c is provided on the second pipeline 102. The third port 6c is connected to the second pipeline 102 through a third pipeline 103 and is located at a position between the first control valve 4c and the first indoor heat exchanger 3b. A second control valve 4d is also provided on the third pipeline 103.

[0100] When the refrigeration system operates in the refrigeration mode, the first control valve 4c is opened, the second control valve 4d is closed. The first port 6a is the refrigerant inlet, the second port 6b is the refrigerant outlet, and the third port 6c is blocked. When the refrigeration system operates in the reheating and dehumidifying mode, the first control valve 4c is closed, the second control valve 4d is opened. The first port 6a is the refrigerant inlet, the second port 6b is blocked, and the third port 6c is the refrigerant outlet.

[0101] This is the preferred structural form of the active adjustment device of the present invention, as well as the specific installation position and connection relationship in the refrigeration system. Through the first port, the second port, and the third port, the hollow active adjustment device can be connected to the exterior. The first port is connected to the first throttling device through the first pipeline, and can receive the gas-liquid mixture throttled from the first throttling device in the refrigeration mode or the reheating and dehumidifying mode. In particular, in the reheating and dehumidifying mode, a certain amount of liquid refrigerant can be effectively stored inside the active adjustment device through the second pipeline to form an outlet. In the refrigeration mode, the refrigerant is directly discharged through the second port, without storing or storing a relatively small amount of liquid refrigerant. And according to the control valves on different pipelines, adaptive control can be carried out according to different modes, effectively completing the flow through the first and second pipelines in the refrigeration mode and through the first and third pipelines in the reheating and dehumidifying mode. As a result, more refrigerant is stored in the active adjustment device in the reheating and dehumidifying mode than in the refrigeration mode, ensuring that the refrigerant circulating in the system is not excessive in the dehumidifying mode and not insufficient in the refrigeration mode, guaranteeing the normal refrigeration and dehumidification functions while improving the system energy efficiency.

[0102] The present invention proposes an active regulation scheme for the refrigerant charge of a two-pipe reheat dehumidification system. First, it can effectively solve the problem of excess refrigerant in the reheat dehumidification operation mode. After the excess refrigerant is stored in the refrigerant regulation device, the subcooling degree of the reheat heat exchanger decreases, the exhaust pressure decreases, the pressure ratio decreases, and the system SMER increases. In addition, as the exhaust pressure and temperature decrease, the maximum outlet air temperature and the maximum dehumidification capacity can continue to increase the frequency to raise the outlet air temperature and the maximum dehumidification capacity when operating (if there is too much refrigerant in the condenser, it will lead to poor heat exchange in the condenser, and the exhaust temperature and pressure will increase; when the system operates at the maximum dehumidification capacity or the highest outlet air temperature, it is mainly restricted by the exhaust temperature or exhaust pressure and cannot continue to increase the frequency. After adding the storage device, the refrigerant in the reheat condenser decreases, the liquid phase region decreases, the heat exchange becomes better, and the exhaust temperature and pressure decrease); Second, it can actively adjust the refrigerant charge of the system under different refrigeration and heating conditions and improve the energy efficiency of the system; Third, when operating in the reheat dehumidification mode, it can effectively improve the comfort in an environment with a not-high temperature and a relatively high humidity.

[0103] In some embodiments,

[0104] The active regulation device 6 is arranged vertically up and down. The first port 6a is located at the upper end of the active regulation device 6, the second port 6b is located at the lower end of the active regulation device 6, and the third port 6c is arranged on the side of the active regulation device 6, and the height of the third port 6c is higher than that of the second port 6b and equal to or lower than that of the first port 6a.

[0105] This is a further preferred structural form of the active regulation device of the present invention, that is, it is arranged vertically up and down, so that the first port is located at the upper end of the active regulation device and the second port is located at the lower end of the active regulation device, so that in the refrigeration mode, the refrigerant enters the active regulation device from the first port and is discharged from the second port at the lower end, and basically or as little as possible refrigerant is stored in the active regulation device. The third port is arranged on the side of the active regulation device, which can make the refrigerant enter the active regulation device from the first port at the upper end in the reheat dehumidification mode. Since the first control valve 4c at the lower end is closed, it needs to accumulate the liquid level height above the third port from the bottom of the active regulation device before it can be discharged. Therefore, in the reheat dehumidification mode, the liquid refrigerant below the liquid level of the third port is stored in the active regulation device, so as to effectively and automatically store the liquid refrigerant according to different modes, effectively solve the problem of the deviation of the refrigerant charge in different operation modes, and improve the energy efficiency of the system.

[0106] In some embodiments,

[0107] The height of the active regulation device 6 is H, that is, the vertical height from the upper end to the lower end of the active regulation device 6 is H, and the height of the third port 6c is h_1, that is, the vertical height of the third port 6c from the lower end of the active regulation device 6 is h_1;

[0108] When the refrigeration system operates in the refrigeration mode, the height of the refrigerant stored in the active adjustment device 6, Δh = 0. When the refrigeration system operates in the reheating and dehumidifying mode, the height of the refrigerant stored in the active adjustment device 6, Δh = h_1.

[0109] This is a further preferred structural form of the active adjustment device of the present invention. The height of the active adjustment device is preferably H, that is, the vertical height from the upper end to the lower end is H, and the height of the third port is h_1. The fact that the height of the liquid refrigerant stored inside the active adjustment device in the refrigeration mode, Δh = 0, indicates that no liquid refrigerant is stored in the active adjustment device in the refrigeration mode. While in the reheating and dehumidifying mode, the height of the liquid refrigerant stored inside the active adjustment device, Δh = h_1. Since h_1 > 0, it makes the height of the liquid refrigerant stored inside the active adjustment device in the reheating and dehumidifying mode, h_1, greater than the amount of refrigerant stored in it in the refrigeration mode. It automatically stores the liquid refrigerant according to different modes, avoids the excess refrigerant in the system cycle in the reheating mode, and also avoids the shortage of refrigerant in the system cycle in the refrigeration mode, effectively solving the problem of the charging amount deviation in different operating modes and improving the energy efficiency of the system.

[0110] In some embodiments,

[0111] When the refrigeration system operates in the heating mode, the first control valve 4c is opened, the second control valve 4d is closed or opened, the first port 6a is the refrigerant outlet, the second port 6b is the refrigerant inlet, and the third port 6c is not connected or is also the refrigerant inlet; the height of the refrigerant stored in the active adjustment device 6, Δh = H.

[0112] This is the preferred control form of the refrigeration system of the present invention in the heating mode, that is, in the refrigeration mode, it enters the inside of the active adjustment device from the second port of the second pipeline from bottom to top. At this time, the first control valve is opened, and the second control valve is closed or opened. The refrigerant can only be discharged when the height of the liquid refrigerant in the active adjustment device reaches the upper end height H, so that the height of the liquid refrigerant stored in the active adjustment device in the heating mode is H. It avoids the excess refrigerant in the system cycle in the heating mode, and also avoids the shortage of refrigerant in the system cycle in the refrigeration mode, effectively solving the problem of the charging amount deviation in different operating modes and improving the energy efficiency of the system.

[0113] The refrigeration and air-conditioning system of the present invention comprises a compressor, an outdoor heat exchanger, a throttling device, an indoor heat exchanger, and an active charge regulation device. The active charge regulation device is located between the outdoor throttling electronic expansion valve (the first throttling device 4a) and the indoor first heat exchanger 3b. Its structure is cylindrical. The opening position of the refrigeration liquid outlet (the second port 6b) is at the center of the lower part of the device. The opening position of the reheating liquid outlet hole (the third port 6c) is on the upper side. The opening position of the heating liquid outlet (the first port 6a) is at the center of the upper part of the device. The refrigeration liquid outlet pipe and the reheating liquid outlet pipe are respectively connected to solenoid valves (the first control valve 4c and the second control valve 4d). The indoor heat exchanger comprises a reheating heat exchanger (the indoor first heat exchanger 3b) and a dehumidifying heat exchanger (the indoor second heat exchanger 3c). An electronic expansion valve (the second throttling device 4b) is arranged between the two heat exchangers. The second throttling device 4b is divided into a small flow rate section and a large flow rate section. In the reheating and dehumidifying mode, the second throttling device 4b is in the small flow rate section (i.e., the throttling state), and the valve body functions the same as an electronic expansion valve. When operating in the refrigeration and heating modes, the second throttling device 4b is in the fully open state with a large flow area, which can ensure that the energy efficiency in the refrigeration and heating modes does not decay. The system charge is preferably charged according to the optimal charge in the refrigeration mode. When operating in the refrigeration mode, the first control valve 4c is turned on, and the second control valve 4d is turned off, and there is no refrigerant storage in the active regulation device. When operating in the heating mode, both control valves (preferably solenoid valves) are turned on, and the refrigerant in the active regulation device is in a full liquid state (usually the volume of the outdoor heat exchanger is larger than that of the indoor heat exchanger, and the dryness of the refrigerant in the condenser is lower than that in the evaporator. When the volumes are the same, the condenser stores more refrigerant, so the refrigerant charge in the refrigeration mode is larger than that in the heating mode). When operating in the reheating and dehumidifying mode, the first control valve 4c is turned off, and the second control valve 4d is turned on, and the refrigerant liquid level in the active regulation device is the same as the height of the reheating liquid outlet.

[0114] In some embodiments,

[0115] The refrigeration system is a series reheating and dehumidifying system. The optimal charges in its refrigeration, heating, and reheating and dehumidifying modes are m_1, m_2, and m_3 respectively. The internal volume of the active regulation device is ΔV, the total height is H, the inner diameter is d, and the height of the side opening is h_1. The dimensions of the active regulation device satisfy the following relationship:

[0116] When (m_1 - m_2) > (m_1 - m_3), this indicates that the charge in the reheating and dehumidifying mode is larger than that in the heating mode;

[0117] ΔV = (m_1 - m_2) / ρ_1 = (πd^2) / 4 * H. This formula is used to calculate the dimensions of the storage device, that is, the design of the device. Therefore, the calculation is based on the heating condition at this time;

[0118] where ρ_1 [kg / m^3] is the saturated liquid density of the refrigerant corresponding to the condensation temperature in the heating mode;

[0119] And there is: (m_1 - m_3) / ρ_2 = (πd^2) / 4 * h_1; This formula is for calculating h_1

[0120] Where ρ_2 [kg / m^3] is the density of the refrigerant saturated liquid corresponding to the condensation temperature in the reheating and dehumidifying mode.

[0121] This is the preferred calculation method for the size (H) of the active adjustment device in the refrigeration system of the present invention. When (m_1 - m_2) > (m_1 - m_3), it indicates that the refrigerant charge in the reheating and dehumidifying mode is larger than that in the heating mode. At this time, the formula ΔV = (m_1 - m_2) / ρ_1 = (πd^2) / 4 * H is substituted with the heating mode (H) to calculate H, so that the calculated result (H) is more accurate; at the same time, by substituting the formula (m_1 - m_3) / ρ_2 = (πd^2) / 4 * h_1 in the reheating and dehumidifying mode, the value of h_1 can be accurately obtained. Therefore, when the refrigerant charge in the reheating and dehumidifying mode is larger than that in the heating mode, the size of the active adjustment device can be accurately designed to meet the effect that the present invention automatically stores liquid refrigerant according to different modes to solve the deviation of the refrigerant charge in different operating modes. It can make the optimal refrigerant charge match the size of the container, and the designed container can store the corresponding refrigerant amounts in the refrigeration, heating, and reheating modes respectively to achieve the effect of the optimal refrigerant charge in the system.

[0122] In some embodiments,

[0123] The refrigeration system is a series reheating and dehumidifying system. The optimal refrigerant charges in its refrigeration, heating, and reheating and dehumidifying modes are m_1, m_2, and m_3 respectively. The internal volume of the active adjustment device is ΔV, the total height is H, the inner diameter is d, and the side opening height is h_1. The size of the active adjustment device satisfies the following relationship:

[0124] When (m_1 - m_2) ≤ (m_1 - m_3), the side opening height h_1 = H, which indicates that the refrigerant charge in the reheating and dehumidifying mode is smaller than or equal to that in the heating mode;

[0125] If designed optimally according to the heating mode, then there is:

[0126] ΔV = (m_1 - m_2) / ρ_1 = (πd^2) / 4 * H; that is, designed according to the heating mode;

[0127] Where ρ_1 [kg / m^3] is the density of the refrigerant saturated liquid corresponding to the condensation temperature in the heating mode;

[0128] If designed optimally according to the reheating and dehumidifying mode, then there is:

[0129] ΔV = (m_1 - m_3) / ρ_2 = (πd^2) / 4 * H; that is, it is designed according to the reheating mode;

[0130] Among them, ρ_2 [kg / m^3] is the saturated liquid density corresponding to the condensation temperature in the reheating and dehumidification mode.

[0131] This is the preferred calculation method for the size (H) of the active adjustment device in the refrigeration system of the present invention. When (m_1 - m_2) ≤ (m_1 - m_3), it indicates that the refrigerant charge in the reheating and dehumidification mode is smaller than or equal to that in the heating mode. At this time, the heating mode (H) can be substituted into the formula ΔV = (m_1 - m_2) / ρ_1 = (πd^2) / 4 * H to calculate H, so that the calculated result (H) is more accurate; at the same time, by substituting into the formula (m_1 - m_3) / ρ_2 = (πd^2) / 4 * H in the reheating and dehumidification mode, the value of H can be accurately obtained. Therefore, when the refrigerant charge in the reheating and dehumidification mode is smaller than or equal to that in the heating mode, the size of the active adjustment device can be accurately designed to meet the effect of automatically storing liquid refrigerant according to different modes in the present invention to solve the problem of refrigerant charge deviation in different operating modes. It can make the optimal refrigerant charge match the size of the container, and the designed container can store the corresponding refrigerant amounts in the refrigeration, heating, and reheating modes respectively to achieve the effect of the optimal refrigerant charge in the system.

[0132] In some embodiments,

[0133] When the refrigeration system is a single-cooling system, the optimal refrigerant charges in its refrigeration and reheating and dehumidification modes are m_1 and m_3 respectively. The internal volume of the active adjustment device is ΔV, the internal diameter of the active adjustment device is d, and the size of the active adjustment device satisfies the following relationship:

[0134] ΔV = (m_1 - m_3) / ρ_2 = (πd^2) / 4 * h_1; at this time, it is a single-cooling system;

[0135] Among them, ρ_2 [kg / m^3] is the refrigerant saturated liquid density corresponding to the condensation temperature during reheating and dehumidification;

[0136] When operating in the reheating and dehumidification mode, the liquid level height of the active adjustment device is the same as the opening height of the third port 6c, that is, h_1 = Δh ≤ H.

[0137] This is the preferred calculation method for the size (h_1) of the active adjustment device in the refrigeration system of a single-cooling system. At this time, there is no heating mode, that is, only the reheating mode is used as a substitute into the formula ΔV = (m_1 - m_3) / ρ_2 = (πd^2) / 4 * h_1 to calculate h_1, so that the calculated result (h_1) is more accurate; therefore, the size of the active adjustment device can be accurately designed in the refrigeration system of the single-cooling system to meet the effect that the present invention automatically stores liquid refrigerant according to different modes to solve the charging deviation in different operating modes.

[0138] In some embodiments,

[0139] In the reheating and dehumidifying mode, the opening degree of the second throttling device 4b is controlled by the superheat degree T_SH at the outlet of the indoor second heat exchanger 3c; if T_SH > T_2, the opening degree of the second throttling device 4b is controlled to increase; if T_SH < T_1, the opening degree of the second throttling device 4b is controlled to decrease; if T_1 < T_SH < T_2, the opening degree of the second throttling device 4b is controlled to remain unchanged; where T_1 and T_2 are both temperature preset values, and 0 < T_1 < T_2.

[0140] This is the specific control form of the second throttling device in the reheating and dehumidifying mode of the present invention, that is, it is controlled by the superheat degree at the outlet of the indoor second heat exchanger. When T_SH > T_2, it means that the superheat degree is too high and the superheat degree needs to be reduced, so the opening degree of the second throttling device is increased to increase the refrigerant flow rate into the indoor second heat exchanger and increase the refrigerant amount for evaporation heat exchange, thereby effectively reducing the superheat degree at the outlet; if T_SH < T_1, it means that the superheat degree is too low and the superheat degree needs to be increased, so the opening degree of the second throttling device is reduced to reduce the refrigerant flow rate into the indoor second heat exchanger and reduce the refrigerant amount for evaporation heat exchange, thereby effectively increasing the superheat degree at the outlet; if T_1 < T_SH < T_2, the opening degree of the current second throttling device remains unchanged to maintain the current superheat degree; so as to be able to effectively and accurately control the superheat degree of reheating and dehumidifying to accurately control the dehumidification in the room.

[0141] In some embodiments,

[0142] It further includes an outdoor fan 5a and an indoor fan 5b. The outdoor fan 5a can drive the air flow to exchange heat with the outdoor heat exchanger 3a, and the indoor fan 5b can drive the air flow to exchange heat with the indoor first heat exchanger 3b and the indoor second heat exchanger 3c;

[0143] When T_1 < T_SH < T_2, the rotational speed of the outdoor fan 5a is controlled according to the return air temperature T_in in the room: when T_in < T_set - Δt, the rotational speed of the outdoor fan is controlled to decrease; when T_in > T_set + Δt, the rotational speed of the outdoor fan is controlled to increase; when T_set - Δt < T_in < T_set + Δt, the rotational speed of the outdoor fan is controlled to remain unchanged; where T_set is the preset temperature value and Δt is the preset temperature difference.

[0144] This is the specific control form of the outdoor fan in the reheating and dehumidifying mode of the present invention. When T_in < T_set - Δt, it indicates that the return air temperature in the room is too low at this time, and it is necessary to reduce the heat exchange amount, especially that of the indoor second heat exchanger. Therefore, the rotational speed of the outdoor fan is controlled to decrease, thereby reducing the heat exchange amount of condensation heat transfer, and further effectively reducing the evaporation heat exchange amount, especially that of the indoor second heat exchanger, so that the return air temperature can be increased; when T_in > T_set + Δt, it indicates that the return air temperature in the room is too high at this time, and it is necessary to increase the heat exchange amount, especially that of the indoor second heat exchanger. Therefore, the rotational speed of the outdoor fan is controlled to increase, increasing the heat exchange amount of condensation heat transfer, and further increasing the evaporation heat exchange amount, especially that of the indoor second heat exchanger, and then effectively reducing the return air temperature; thus, the rotational speed of the outdoor fan is controlled according to the high or low return air temperature in the room, and the return air temperature in the room is accurately controlled to reach the preset range T_set - Δt < T_in < T_set + Δt, meeting the requirements of indoor comfort. The control of the return air temperature in the room of the present invention needs to be carried out on the premise of meeting T_1 < T_SH < T_2, in order to first ensure the stability of the system (reflected by the outlet superheat) and then control the return air temperature to achieve the required control of the indoor temperature and humidity.

[0145] The present invention also provides a control method for a refrigeration system as described above, which includes:

[0146] A detection step of detecting the operating mode of the refrigeration system;

[0147] A judgment step of judging whether the operating mode is a refrigeration mode or a reheating and dehumidifying mode;

[0148] A control step of, when the refrigeration system operates in the refrigeration mode, controlling the first control valve 4c to open and the second control valve 4d to close; when the refrigeration system operates in the reheating and dehumidifying mode, controlling the first control valve 4c to close and the second control valve 4d to open.

[0149] This is the preferred control mode of the refrigeration system of the present invention, which can be controlled according to the operating mode, whether it is in the refrigeration mode or the reheating and dehumidification mode. It enables the refrigerant storage amount in the active regulating device in the reheating and dehumidification mode to be greater than that in the refrigeration mode, so that the refrigerant circulating in the system in the dehumidification mode will not be excessive, and the refrigerant circulating in the system in the refrigeration mode will not be insufficient, ensuring the normal refrigeration and dehumidification functions while improving the system energy efficiency.

[0150] When the present invention operates in the refrigeration mode, the four-way reversing valve 2 is in the power-off state, the solenoid valve (the first control valve 4c) is in the conducting state, the solenoid valve (the second control valve 4d) is in the closed state, and the indoor electronic expansion valve (the second throttling device 4b) is in the fully open state. The high-temperature and high-pressure exhaust gas of the compressor enters the outdoor heat exchanger 3a through the four-way reversing valve 2 and condenses into a high-temperature and high-pressure refrigerant subcooled liquid. The subcooled refrigerant liquid enters the active regulating device 6 after throttling and pressure reduction through the first throttling device 4a. At this time, the liquid level △h in the active regulating device is 0, and then it enters the indoor first heat exchanger 3b and the indoor second heat exchanger 3c through the first control valve 4c and evaporates into saturated or superheated steam, and then enters the suction chamber of the compressor 1 through the four-way reversing valve 2 to complete the system cycle.

[0151] When operating in the reheating mode, the four-way reversing valve 2 is in the power-off state, the first control valve 4c is in the closed state, and the second control valve 4d is in the conducting state. The compressor exhaust gas enters the outdoor heat exchanger 3a through the four-way reversing valve 2 for condensation respectively. To ensure that the indoor first heat exchanger 3b has a relatively high condensation temperature and reduce the pressure drop between the outdoor condenser and the reheating heat exchanger, the first throttling device 4a should be in the fully open state. The two-phase refrigerant flowing through the outdoor heat exchanger 3a will enter the charging active regulating device after pressure reduction through the first throttling device 4a. At this time, the liquid level △h of the active regulating device 6 is h_1, and then it enters the indoor first heat exchanger 3b through the second control valve 4d to exchange heat with the indoor air and condense. The second throttling device 4b is in the small flow rate section (throttling state), and the second throttling device 4b adjusts the opening according to the temperature difference T_SH between the outlet temperature of the indoor second heat exchanger 3c and the intermediate temperature. The refrigerant is throttled and depressurized to a two-phase state through the second throttling device 4b and enters the indoor second heat exchanger 3c to exchange heat with the air and evaporate into a saturated or superheated state and then enters the suction chamber of the compressor 1 through the four-way reversing valve 2. Part of the indoor air is cooled and dehumidified by the indoor second heat exchanger 3c, and the other part of the air is heated and the temperature rises through the indoor first heat exchanger 3b. After the two parts of the air are mixed, the dry bulb temperature remains unchanged compared with that before treatment, and the relative humidity decreases, thus realizing the reheating and dehumidification mode.

[0152] In some embodiments,

[0153] When the refrigeration system further includes a four-way reversing valve 2:

[0154] The judgment step is to judge whether the operating mode is a refrigeration mode, a heating mode or a reheating and dehumidification mode;

[0155] The control step is that when the refrigeration system operates in the heating mode, control the first control valve 4c to open, and control the second control valve 4d to open or close.

[0156] This is the control form preferably adopted by the refrigeration system of the present invention in the heating mode, which can make the amount of liquid refrigerant stored in the active regulating device in the heating mode less than that in the refrigeration mode, avoid excess refrigerant in the system cycle in the heating mode, and also avoid insufficient refrigerant in the system cycle in the refrigeration mode, effectively solve the problem of charging deviation in different operating modes, and improve the energy efficiency of the system.

[0157] When operating in the heating mode, the four-way reversing valve 2 is in the energized state, the first control valve 4c and the second control valve 4d are both in the conducting state, the second throttling device 4b is in the fully open state, the high-temperature and high-pressure exhaust gas of the compressor enters the indoor first heat exchanger 3b and the indoor second heat exchanger 3c through the four-way reversing valve 2 and condenses into a subcooled liquid, and then enters the active regulating device 6 through the first control valve 4c and the second control valve 4d (the first control valve 4c can be opened only, and the purpose of opening them simultaneously is to reduce the pressure drop). At this time, a part of the liquid refrigerant will be stored in the charging active regulating device, and the liquid level △h = H in this device, and then it is throttled and depressurized by the first throttling device 4a into a low-temperature and low-pressure two-phase liquid refrigerant and enters the outdoor heat exchanger 3a respectively for evaporation to saturated or superheated steam, and then enters the suction chamber of the compressor 1 through the four-way reversing valve 2 to complete the system cycle.

[0158] In some embodiments,

[0159] When the refrigeration system operates in the reheating and dehumidification mode:

[0160] The detection step further detects the intermediate saturation temperature and the outlet temperature of the indoor second heat exchanger 3c to calculate the outlet superheat degree T_SH;

[0161] The judgment step is to respectively judge the relationship between T_SH and T_1 and T_2, where T_1 and T_2 are both temperature preset values, and 0 < T_1 < T_2;

[0162] The control step is that if T_SH > T_2, then control the opening degree of the second throttling device 4b to increase; if T_SH < T_1, then control the opening degree of the second throttling device 4b to decrease; if T_1 < T_SH < T_2, then control the opening degree of the second throttling device 4b to remain unchanged.

[0163] This is the specific control form of the second throttling device in the reheating and dehumidifying mode of the present invention, that is, it is controlled by the superheat at the outlet of the indoor second heat exchanger. When T_SH > T_2, it indicates that the superheat is too high and the superheat needs to be reduced. Then, by increasing the opening degree of the second throttling device, the refrigerant flow rate into the indoor second heat exchanger is increased, and the refrigerant amount for evaporative heat exchange is increased, thereby effectively reducing the superheat at the outlet. If T_SH < T_1, it indicates that the superheat is too low and the superheat needs to be increased. Then, by reducing the opening degree of the second throttling device, the refrigerant flow rate into the indoor second heat exchanger is reduced, and the refrigerant amount for evaporative heat exchange is reduced, thereby effectively increasing the superheat at the outlet. If T_1 < T_SH < T_2, the opening degree of the current second throttling device remains unchanged to maintain the current superheat, so as to effectively and accurately control the superheat of reheating and dehumidifying and accurately control the dehumidification degree indoors.

[0164] The operation flowchart of the reheating and dehumidifying mode of the present invention is as Figure 7 shown. After entering the dehumidifying mode, the first throttling device 4a (preferably an electronic expansion valve) is in the fully open state, the first control valve 4c is in the closed state, the second control valve 4d is in the conducting state, and the second throttling device 4b (preferably an electronic expansion valve) is in the small flow rate section (i.e., throttling). The outlet superheat T_SH is obtained by detecting the difference between the intermediate saturation temperature and the outlet temperature of the dehumidifying heat exchanger (indoor second heat exchanger 3c), and the second throttling device 4b is used to adjust the outlet superheat T_SH of the heat exchanger. The range of T_SH is 0 to 5°C, and the preferred range is 1 to 2°C.

[0165] In some embodiments,

[0166] when there are also an outdoor fan 5a and an indoor fan 5b and T_1 < T_SH < T_2:

[0167] In the detection step, the return air temperature T_in of the room is also detected;

[0168] In the judgment step, the relationships between T_in and T_set - Δt and T_set + Δt are respectively judged, where T_set is the temperature preset value and Δt is the preset temperature difference;

[0169] In the control step, when T_in < T_set - Δt, the rotation speed of the outdoor fan is controlled to decrease; when T_in > T_set + Δt, the rotation speed of the outdoor fan is controlled to increase; when T_set - Δt < T_in < T_set + Δt, the rotation speed of the outdoor fan is controlled to remain unchanged.

[0170] This is the specific control form of the outdoor fan in the reheating and dehumidifying mode of the present invention. When T_in < T_set - Δt, it indicates that the indoor return air temperature is too low at this time, and it is necessary to reduce the heat exchange amount, especially that of the indoor second heat exchanger. Therefore, the rotational speed of the outdoor fan is controlled to decrease, thereby reducing the heat exchange amount of condensation heat transfer, and further effectively reducing the evaporation heat exchange amount of the indoor second heat exchanger, so that the return air temperature rises; when T_in > T_set + Δt, it indicates that the indoor return air temperature is too high at this time, and it is necessary to increase the heat exchange amount, especially that of the indoor second heat exchanger. Therefore, the rotational speed of the outdoor fan is controlled to increase, increasing the heat exchange amount of condensation heat transfer, and further increasing the evaporation heat exchange amount of the indoor second heat exchanger, thereby effectively reducing the return air temperature; thus, the rotational speed of the outdoor fan is controlled according to the level of the indoor return air temperature, and the indoor return air temperature is accurately controlled to reach the preset range T_set - Δt < T_in < T_set + Δt, meeting the requirements of indoor comfort. The control of the indoor return air temperature of the present invention needs to be carried out on the premise of satisfying T_1 < T_SH < T_2, in order to first ensure the stability of the system (reflected by the outlet superheat) and then control the return air temperature, so as to achieve the required control of the indoor temperature and humidity.

[0171] The refrigeration system of the present invention adjusts the outlet air temperature by adjusting the rotational speed of the outdoor fan, detects the indoor return air temperature T_in, and when T_in < T_set - Δt, reduces the outdoor wind speed until it reaches T_set - Δt

[0172] <T_in < T_set + Δt, and Δt is 0.5°C. When T_in > T_set + Δt, the outdoor wind speed is increased until T_set - Δt < T_in < T_set + Δt is reached.

[0173] The present invention also provides an air conditioner, which includes the aforementioned refrigeration system.

[0174] By adopting the active refrigerant charge adjustment scheme, the air conditioner of the present invention can adjust the optimal refrigerant charge in the refrigeration, heating, and reheating and dehumidifying modes. On the one hand, it improves the system performance and SMER, and on the other hand, it increases the highest outlet air temperature and the maximum dehumidification capacity of the system. The system has a higher SMER, a larger dehumidification capacity, and a wider adjustment range of the outlet air temperature.

[0175] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention. The above is only the preferred implementation manner of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A refrigeration system, characterized in that: Comprising: A compressor (1), an outdoor heat exchanger (3a), a first indoor heat exchanger (3b), a second indoor heat exchanger (3c), a first throttling device (4a) and a second throttling device (4b). Along the refrigerant flow direction, the compressor (1), the outdoor heat exchanger (3a), the first throttling device (4a), the first indoor heat exchanger (3b), the second throttling device (4b) and the second indoor heat exchanger (3c) can be directly or indirectly connected in sequence to form a refrigeration cycle loop; The refrigeration system further includes an active adjustment device (6). The active adjustment device (6) is arranged between the first throttling device (4a) and the first indoor heat exchanger (3b), and the active adjustment device (6) can store refrigerant therein. The active adjustment device (6) can store different amounts of refrigerant according to different operating modes. When the refrigeration system operates in the refrigeration mode, the volume of the refrigerant stored in the active adjustment device (6) is V1. When the refrigeration system operates in the reheating and dehumidifying mode, the volume of the refrigerant stored in the active adjustment device (6) is V2, and V2 > V1 ≥ 0; The refrigeration system is a series reheating and dehumidifying system. The optimal refrigerant charges for its refrigeration, heating and reheating and dehumidifying modes are m_1, m_2 and m_3 respectively. The internal volume of the active adjustment device is ΔV, and the inner diameter is d. The size of the active adjustment device satisfies the following relationship: When (m_1 - m_2) > (m_1 - m_3), ΔV = (m_1 - m_2) / ρ_1 = (πd^2) / 4 * H; where ρ_1 is the refrigerant saturated liquid density corresponding to the condensation temperature in the heating mode; and there is: (m_1 - m_3) / ρ_2 = (πd^2) / 4 * h_1; where ρ_2 is the refrigerant saturated liquid density corresponding to the condensation temperature in the reheating and dehumidifying mode.

2. The refrigeration system according to claim 1, characterized in that: It further includes a four-way reversing valve (2). Four ends of the four-way reversing valve (2) are respectively connected to the outlet of the compressor (1), the inlet of the compressor (1), one end of the outdoor heat exchanger (3a) and one end of the second indoor heat exchanger (3c); Along the refrigerant flow direction, the compressor (1), the second indoor heat exchanger (3c), the second throttling device (4b), the first indoor heat exchanger (3b), the active adjustment device (6), the first throttling device (4a) and the outdoor heat exchanger (3a) can be directly or indirectly connected in sequence, that is, a heating cycle loop can also be formed; when the refrigeration system operates in the heating mode, the volume of the refrigerant stored in the active adjustment device (6) is V3, and V3 ≥ V1 ≥ 0.

3. The refrigeration system according to claim 1, characterized in that: The active regulating device (6) is a hollow container with a first port (6a), a second port (6b) and a third port (6c). The first port (6a), the second port (6b) and the third port (6c) can respectively connect the interior of the container to the exterior. The first port (6a) is connected to one end of the first throttling device (4a) through a first pipeline (101). The second port (6b) is connected to one end of the first indoor heat exchanger (3b) through a second pipeline (102). A first control valve (4c) is arranged on the second pipeline (102). The third port (6c) is connected to the second pipeline (102) through a third pipeline (103) and is located at a position between the first control valve (4c) and the first indoor heat exchanger (3b). A second control valve (4d) is also arranged on the third pipeline (103); When the refrigeration system operates in the refrigeration mode, the first control valve (4c) is opened, the second control valve (4d) is closed, the first port (6a) is the refrigerant inlet, the second port (6b) is the refrigerant outlet, and the third port (6c) is blocked. When the refrigeration system operates in the reheating and dehumidifying mode, the first control valve (4c) is closed, the second control valve (4d) is opened, the first port (6a) is the refrigerant inlet, the second port (6b) is blocked, and the third port (6c) is the refrigerant outlet.

4. The refrigeration system according to claim 3, wherein: The active regulating device (6) is arranged vertically up and down. The first port (6a) is located at the upper end of the active regulating device (6), the second port (6b) is located at the lower end of the active regulating device (6), the third port (6c) is arranged on the side of the active regulating device (6), and the height of the third port (6c) is higher than that of the second port (6b) and equal to or lower than that of the first port (6a).

5. The refrigeration system according to claim 4, wherein: The height of the active regulating device (6) is H, that is, the vertical height from the upper end to the lower end of the active regulating device (6) is H. The height of the third port (6c) is h_1, that is, the vertical height from the third port (6c) to the lower end of the active regulating device (6) is h_1; When the refrigeration system operates in the refrigeration mode, the height of the refrigerant stored in the active regulating device (6) Δh = 0. When the refrigeration system operates in the reheating and dehumidifying mode, the height of the refrigerant stored in the active regulating device (6) Δh = h_1.

6. The refrigeration system according to claim 5, wherein: When the refrigeration system operates in the heating mode, the first control valve (4c) is opened, the second control valve (4d) is closed or opened, the first port (6a) is the refrigerant outlet, the second port (6b) is the refrigerant inlet, and the third port (6c) is blocked or also the refrigerant inlet; the height of the refrigerant stored in the active regulating device (6) Δh = H.

7. The refrigeration system according to claim 6, characterized in that: The refrigeration system is a series reheat dehumidification system, and the optimal refrigerant charges in its refrigeration, heating and reheat dehumidification modes are m_1, m_2 and m_3 respectively. The internal volume of the active regulating device is ΔV, and the inner diameter is d. The dimensions of the active regulating device satisfy the following relationship: When (m_1 - m_2) ≤ (m_1 - m_3), h_1 = H, If designed optimally according to the heating mode, then: ΔV = (m_1 - m_2) / ρ_1 = (πd^2) / 4 * H; where ρ_1 is the saturated liquid density of the refrigerant corresponding to the condensation temperature in the heating mode; If designed optimally according to the reheat dehumidification mode, then: ΔV = (m_1 - m_3) / ρ_2 = (πd^2) / 4 * H; where ρ_2 is the saturated liquid density corresponding to the condensation temperature in the reheat dehumidification mode.

8. The refrigeration system according to claim 6, characterized in that: When the refrigeration system is a single-cooling system, the optimal refrigerant charges in its refrigeration and reheat dehumidification modes are m_1 and m_2 respectively. The internal volume of the active regulating device is ΔV, and the internal volume of the active regulating device is ΔV, and the inner diameter is d. The dimensions of the active regulating device satisfy the following relationship: ΔV = (m_1 - m_2) / ρ_2 = πd^2 / 4 * h_1; where ρ_2 is the saturated liquid density of the refrigerant corresponding to the condensation temperature during reheat dehumidification; During the operation of the reheat dehumidification mode, the liquid level height of the active regulating device is the same as the opening height of the third port (6c), that is, h_1 = Δh ≤ H.

9. The refrigeration system according to any one of claims 3 - 8, characterized in that: In the reheat dehumidification mode, the opening degree of the second throttling device (4b) is controlled by the superheat degree T_SH at the outlet of the indoor second heat exchanger (3c); if T_SH > T_2, then control the opening degree of the second throttling device (4b) to increase; if T_SH < T_1, then control the opening degree of the second throttling device (4b) to decrease; if T_1 < T_SH < T_2, then control the opening degree of the second throttling device (4b) to remain unchanged; where T_1 and T_2 are both temperature preset values, and 0 < T_1 < T_2.

10. The refrigeration system according to claim 9, characterized in that: It further includes an outdoor fan (5a) and an indoor fan (5b). The outdoor fan (5a) can drive air flow to exchange heat with the outdoor heat exchanger (3a), and the indoor fan (5b) can drive air flow to exchange heat with the indoor first heat exchanger (3b) and the indoor second heat exchanger (3c); When T_1 < T_SH < T_2, the rotational speed of the outdoor fan (5a) is controlled according to the return air temperature T_in indoors: when T_in < T_set - Δt, the rotational speed of the outdoor fan is controlled to decrease; when T_in > T_set + Δt, the rotational speed of the outdoor fan is controlled to increase; when T_set - Δt < T_in < T_set + Δt, the rotational speed of the outdoor fan is controlled to remain unchanged; where T_set is the temperature preset value and Δt is the preset temperature difference.

11. A control method for a refrigeration system according to any one of claims 3-10, characterized in that: Comprising: A detection step of detecting the operating mode of the refrigeration system; A judgment step of judging whether the operating mode is a refrigeration mode or a reheating and dehumidification mode; A control step of, when the refrigeration system operates in the refrigeration mode, controlling the first control valve (4c) to open and controlling the second control valve (4d) to close; when the refrigeration system operates in the reheating and dehumidification mode, controlling the first control valve (4c) to close and controlling the second control valve (4d) to open.

12. The control method according to claim 11, wherein: When the refrigeration system further includes a four-way reversing valve (2): The judgment step of judging whether the operating mode is a refrigeration mode or a heating mode or a reheating and dehumidification mode; The control step of, when the refrigeration system operates in the heating mode, controlling the first control valve (4c) to open and controlling the second control valve (4d) to close or open.

13. The control method according to claim 11, wherein: When the refrigeration system operates in the reheating and dehumidification mode: The detection step further detects the intermediate saturation temperature and the outlet temperature of the indoor second heat exchanger (3c) to calculate the outlet superheat T_SH; The judgment step respectively judges the relationship between T_SH and T_1 and T_2, where T_1 and T_2 are both temperature preset values and 0 < T_1 < T_2; The control step, if T_SH > T_2, controls the opening degree of the second throttling device (4b) to increase; if T_SH < T_1, controls the opening degree of the second throttling device (4b) to decrease; if T_1 < T_SH < T_2, controls the opening degree of the second throttling device (4b) to remain unchanged.

14. The control method according to claim 13, wherein: When there are further an outdoor fan (5a) and an indoor fan (5b) and T_1 < T_SH < T_2: The detection step further detects the return air temperature T_in indoors; The judgment step respectively judges the relationship between T_in and T_set - Δt and T_set + Δt, where T_set is the temperature preset value and Δt is the preset temperature difference; The control step, when T_in < T_set - Δt, controls the rotational speed of the outdoor fan to decrease; when T_in > T_set + Δt, controls the rotational speed of the outdoor fan to increase; when T_set - Δt < T_in < T_set + Δt, controls the rotational speed of the outdoor fan to remain unchanged.

15. An air conditioner, characterized in that: Comprising the refrigeration system according to any one of claims 1 - 10.

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