Single-stage compression air conditioning system and control method thereof

Abstract

The present invention provides a single-stage compression air conditioning system and a control method thereof. The single-stage compression air conditioning system includes: a compressor, a first countercurrent heat exchanger, a first heat exchanger, a second heat exchanger, a third heat exchanger, and a second countercurrent heat exchanger. The air conditioning system includes a non-azeotropic refrigerant. In cooling mode, the first countercurrent heat exchanger and the first heat exchanger form a primary condensation, and the second heat exchanger forms a secondary condensation; the third heat exchanger forms a primary evaporation, and the second countercurrent heat exchanger forms a secondary evaporation; in heating mode, the second countercurrent heat exchanger forms a primary condensation, the third heat exchanger forms a secondary condensation, the first heat exchanger forms a primary evaporation, and the first countercurrent heat exchanger forms a secondary evaporation. According to the present invention, dual condensing temperatures and dual evaporating temperatures are effectively achieved in the single-stage compression system, thereby effectively reducing the heat exchange temperature difference and irreversible losses in the heat exchange process, thereby effectively improving the energy efficiency of the system.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning, and in particular to a single-stage compression air conditioning system and a control method thereof. Background Art

[0002] In recent years, with the accelerated pace of refrigerant replacement, traditional pure refrigerants are difficult to balance low flammability, low GWP, and good thermodynamic properties. Therefore, people have turned their attention to mixed refrigerants to seek breakthroughs. The non-azeotropic refrigerant in the mixed refrigerant can not only balance the physical properties of the refrigerant, but also has temperature slip during the heat exchange process, which allows it to approach the Lorenz cycle during the heat exchange process to improve the system energy efficiency, and has attracted the attention of more scholars.

[0003] However, to fully utilize the temperature glide characteristics of non-azeotropic refrigerants and construct a Lorenz cycle, the non-azeotropic refrigerant should exchange heat in countercurrent with the heat exchange fluid, while traditional fin-tube heat exchangers generally use cross-flow heat exchange. Furthermore, conventional dual-temperature or multi-temperature air conditioning systems typically use dual (or multi-) cylinder compressors to achieve two or more evaporating temperatures. These systems have complex compressor and system structures and numerous valve components, increasing the risk of refrigerant leakage and threatening the safety of indoor occupants.

[0004] Since the single-stage compression refrigeration cycle system in the prior art has technical problems such as large heat exchange temperature difference resulting in large irreversible losses in the heat exchange process and low system energy efficiency, the present invention studies and designs a single-stage compression air-conditioning system and its control method. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the single-stage compression refrigeration cycle system in the prior art, such as the large heat exchange temperature difference resulting in large irreversible losses in the heat exchange process and low system energy efficiency, thereby providing a single-stage compression air-conditioning system and its control method.

[0006] In order to solve the above problems, the present invention provides a single-stage compression air conditioning system, which includes:

[0007] A compressor, a first counter-flow heat exchanger, a first heat exchanger, a second heat exchanger, a third heat exchanger, and a second counter-flow heat exchanger, wherein the air-conditioning system includes a non-azeotropic refrigerant consisting of a first boiling point refrigerant and a second boiling point refrigerant, wherein the boiling point of the first boiling point refrigerant is less than the boiling point of the second boiling point refrigerant,

[0008] In cooling mode, the first counter-flow heat exchanger is connected to the exhaust port of the compressor, the first counter-flow heat exchanger and the first heat exchanger form a primary condensation or the first counter-flow heat exchanger alone forms a primary condensation, and the second heat exchanger is connected to the downstream end of the first heat exchanger in the refrigerant flow direction to form a secondary condensation; the third heat exchanger forms a primary evaporation, and the second counter-flow heat exchanger is connected to the downstream end of the third heat exchanger in the refrigerant flow direction to form a secondary evaporation;

[0009] In the heating mode, the second counter-flow heat exchanger is connected to the exhaust end of the compressor, and the second counter-flow heat exchanger forms a primary condensation. The third heat exchanger is connected to the downstream end of the refrigerant flow direction of the second counter-flow heat exchanger to form a secondary condensation. The first heat exchanger forms a primary evaporation. The first counter-flow heat exchanger is connected to the downstream end of the refrigerant flow direction of the first heat exchanger to form a secondary evaporation.

[0010] In some embodiments, it includes a first pipeline, a second pipeline, a third pipeline, a fourth pipeline, a fifth pipeline, a sixth pipeline and a first throttling device, one end of the first pipeline can be connected to the compressor, and the other end is connected to one end of the first countercurrent heat exchanger, one end of the second pipeline is connected to the other end of the first countercurrent heat exchanger, and the other end of the second pipeline is connected to one end of the first heat exchanger, one end of the third pipeline is connected to the other end of the first heat exchanger, and the other end of the third pipeline is connected to one end of the first throttling device, one end of the fourth pipeline is connected to the other end of the first throttling device, and the other end of the fourth pipeline is connected to one end of the third heat exchanger, one end of the fifth pipeline is connected to the other end of the third heat exchanger, and the other end of the fifth pipeline is connected to one end of the second countercurrent heat exchanger, one end of the sixth pipeline is connected to the other end of the second countercurrent heat exchanger, and the other end of the sixth pipeline can be connected to the compressor.

[0011] In some embodiments, in cooling mode, the first counter-flow heat exchanger and the first heat exchanger form a primary condensation, the second heat exchanger is connected to the downstream end of the first heat exchanger in the refrigerant flow direction to form a secondary condensation, the third heat exchanger forms a primary evaporation, and the second counter-flow heat exchanger is connected to the downstream end of the third heat exchanger in the refrigerant flow direction to form a secondary evaporation;

[0012] In the heating mode, the second counter-flow heat exchanger forms a primary condensation, the third heat exchanger is connected to the downstream end of the second counter-flow heat exchanger in the refrigerant flow direction to form a secondary condensation, the first heat exchanger forms a primary evaporation, and the first counter-flow heat exchanger is connected to the downstream end of the first heat exchanger in the refrigerant flow direction to form a secondary evaporation.

[0013] In some embodiments, it also includes a seventh pipeline, an eighth pipeline, a ninth pipeline and a second throttling device, one end of the seventh pipeline is connected to the third pipeline, and the other end is connected to one end of the second heat exchanger, one end of the eighth pipeline is connected to the other end of the second heat exchanger, and the other end of the eighth pipeline is connected to one end of the second throttling device, one end of the ninth pipeline is connected to the other end of the second throttling device, and the other end of the ninth pipeline is connected to the fourth pipeline.

[0014] In some embodiments, the refrigerant in the first countercurrent heat exchanger exchanges heat with the water in the casing in a countercurrent manner. The first heat exchanger is an outdoor heat exchanger, and the refrigerant therein exchanges heat with the outdoor air. The third heat exchanger and the second heat exchanger form a heat exchanger group for dehumidifying the indoor space. The refrigerant in the third heat exchanger can cool the air. The air cooled by the third heat exchanger exchanges heat in the second heat exchanger and is heated before entering the indoor space.

[0015] In some embodiments, in cooling mode, the first counter-flow heat exchanger alone forms a primary condensation, the first heat exchanger and the second heat exchanger are connected in parallel and connected to the downstream end of the first counter-flow heat exchanger in the refrigerant flow direction to form a secondary condensation, the third heat exchanger forms a primary evaporation, and the second counter-flow heat exchanger is connected to the downstream end of the third heat exchanger in the refrigerant flow direction to form a secondary evaporation;

[0016] In the heating mode, the second counter-flow heat exchanger forms a primary condensation, the third heat exchanger is connected to the downstream end of the second counter-flow heat exchanger in the refrigerant flow direction to form a secondary condensation, the first heat exchanger forms a primary evaporation, and the first counter-flow heat exchanger is connected to the downstream end of the first heat exchanger in the refrigerant flow direction to form a secondary evaporation.

[0017] In some embodiments, it also includes a seventh pipeline, an eighth pipeline, a ninth pipeline and a second throttling device, one end of the seventh pipeline is connected to the second pipeline, and the other end is connected to one end of the second heat exchanger, one end of the eighth pipeline is connected to the other end of the second heat exchanger, and the other end of the eighth pipeline is connected to one end of the second throttling device, one end of the ninth pipeline is connected to the other end of the second throttling device, and the other end of the ninth pipeline is connected to the fourth pipeline.

[0018] In some embodiments, the refrigerant in the first countercurrent heat exchanger exchanges heat with the water in the casing in countercurrent. The first heat exchanger is arranged in the indoor exhaust duct and exchanges heat with the indoor exhaust air to supercool the refrigerant. The third heat exchanger and the second heat exchanger form a heat exchanger group for dehumidifying the room. The refrigerant in the third heat exchanger can cool the air. The air cooled by the third heat exchanger is heated by heat exchange in the second heat exchanger and enters the room.

[0019] In some embodiments, in cooling mode, the first counter-flow heat exchanger alone forms a primary condensation, the first heat exchanger and the second heat exchanger are connected in series and connected to the downstream end of the first counter-flow heat exchanger in the refrigerant flow direction to form a secondary condensation, the third heat exchanger forms a primary evaporation, and the second counter-flow heat exchanger is connected to the downstream end of the third heat exchanger in the refrigerant flow direction to form a secondary evaporation;

[0020] In the heating mode, the second counter-flow heat exchanger forms a primary condensation, the third heat exchanger is connected to the downstream end of the second counter-flow heat exchanger in the refrigerant flow direction to form a secondary condensation, the first heat exchanger forms a primary evaporation, and the first counter-flow heat exchanger is connected to the downstream end of the first heat exchanger in the refrigerant flow direction to form a secondary evaporation.

[0021] In some embodiments, it also includes a seventh pipeline, an eighth pipeline, a ninth pipeline and a second throttling device, one end of the seventh pipeline is connected to the third pipeline, and the other end is connected to one end of the second heat exchanger, one end of the eighth pipeline is connected to the other end of the second heat exchanger, and the other end of the eighth pipeline is connected to one end of the second throttling device, one end of the ninth pipeline is connected to the other end of the second throttling device, and the other end of the ninth pipeline is connected to the fourth pipeline.

[0022] In some embodiments, the refrigerant in the first countercurrent heat exchanger exchanges heat with the water in the casing in countercurrent. The first heat exchanger is arranged in the indoor exhaust duct and exchanges heat with the indoor exhaust air to supercool the refrigerant. The third heat exchanger and the second heat exchanger form a heat exchanger group for dehumidifying the room. The refrigerant in the third heat exchanger can cool the air. The air cooled by the third heat exchanger is heated by heat exchange in the second heat exchanger and enters the room.

[0023] In some embodiments, a tenth pipeline, an eleventh pipeline and a four-way valve are further included, the four-way valve includes a C tube, a D tube, an E tube and an S tube, and one end of the tenth pipeline is connected to the exhaust end of the compressor, and the other end is connected to the D tube, the first pipeline is connected between the C tube and the first countercurrent heat exchanger, one end of the eleventh pipeline is connected to the suction end of the compressor, and the other end is connected to the S tube, and the sixth pipeline is connected between the second countercurrent heat exchanger and the E tube; and in cooling mode, the C tube is connected to the D tube and the S tube is connected to the E tube at the same time, and in heating mode, the C tube is connected to the S tube and the D tube is connected to the E tube at the same time.

[0024] In some embodiments, it also includes multiple indoor terminal heat exchangers arranged in parallel to form a multi-connected air-conditioning system. The multiple indoor terminal heat exchangers are all connected to the second countercurrent heat exchanger. A coolant flows in the indoor terminal heat exchanger, and the coolant exchanges heat with the refrigerant in the second countercurrent heat exchanger.

[0025] The present invention further provides a control method for a single-stage compression air conditioning system as described in any of the preceding items, wherein when the single-stage compression air conditioning system includes both a first throttling device and a second throttling device, the control method comprises:

[0026] a judging step of judging whether the operating mode of the single-stage compression air-conditioning system is a cooling mode or a heating mode;

[0027] A control step, when the operating mode is a cooling mode, controlling both the first throttling device and the second throttling device to be opened, or closing the first throttling device and opening the second throttling device at the same time; when the operating mode is a heating mode, controlling the first throttling device to be opened and closing the second throttling device at the same time.

[0028] In some embodiments, when the single-stage compression air conditioning system includes a seventh pipeline, an eighth pipeline, a ninth pipeline, and a second throttling device, one end of the seventh pipeline is connected to the third pipeline and the other end is connected to one end of the second heat exchanger, one end of the eighth pipeline is connected to the other end of the second heat exchanger, the other end of the eighth pipeline is connected to one end of the second throttling device, one end of the ninth pipeline is connected to the other end of the second throttling device, and the other end of the ninth pipeline is connected to the fourth pipeline:

[0029] The control step controls both the first throttling device and the second throttling device to be opened when the operating mode is the cooling mode, and controls the first throttling device to be opened while closing the second throttling device when the operating mode is the heating mode.

[0030] In some embodiments, when the single-stage compression air conditioning system includes a seventh pipeline, an eighth pipeline, a ninth pipeline, and a second throttling device, one end of the seventh pipeline is connected to the second pipeline and the other end is connected to one end of the second heat exchanger, one end of the eighth pipeline is connected to the other end of the second heat exchanger, the other end of the eighth pipeline is connected to one end of the second throttling device, one end of the ninth pipeline is connected to the other end of the second throttling device, and the other end of the ninth pipeline is connected to the fourth pipeline:

[0031] The control step controls both the first throttling device and the second throttling device to be opened when the operating mode is the cooling mode, and controls the first throttling device to be opened while closing the second throttling device when the operating mode is the heating mode.

[0032] In some embodiments, when the single-stage compression air conditioning system includes a seventh pipeline, an eighth pipeline, a ninth pipeline, and a second throttling device, one end of the seventh pipeline is connected to the third pipeline and the other end is connected to one end of the second heat exchanger, one end of the eighth pipeline is connected to the other end of the second heat exchanger, the other end of the eighth pipeline is connected to one end of the second throttling device, one end of the ninth pipeline is connected to the other end of the second throttling device, and the other end of the ninth pipeline is connected to the fourth pipeline:

[0033] The control step controls the first throttling device to be closed and the second throttling device to be opened when the operating mode is the cooling mode, and controls the first throttling device to be opened and the second throttling device to be closed when the operating mode is the heating mode.

[0034] The single-stage compression air conditioning system and control method thereof provided by the present invention have the following beneficial effects:

[0035] The present invention introduces at least two non-azeotropic refrigerants into the circulation loop of the single-stage compression air-conditioning system, and sets a first counterflow heat exchanger, a first heat exchanger, a second heat exchanger, a third heat exchanger and a second counterflow heat exchanger in the system, and forms a unique connection mode, which can effectively utilize the temperature glide characteristics of the non-azeotropic refrigerant, and can form a first-stage condensation in the first counterflow heat exchanger and the first heat exchanger in the cooling mode, or the first counterflow heat exchanger forms a first-stage condensation alone, and the second heat exchanger is connected to the downstream end of the refrigerant flow direction of the first heat exchanger to form a second-stage condensation, or the first heat exchanger and the second heat exchanger are connected in parallel to the downstream end of the refrigerant flow direction of the first counterflow heat exchanger to form a second-stage condensation, or the first heat exchanger and the second heat exchanger are connected in series to the first counterflow heat exchanger. The second counter-flow heat exchanger is connected to the downstream end of the refrigerant flow direction of the third heat exchanger to form a secondary condensation; the third heat exchanger forms a primary evaporation, and the second counter-flow heat exchanger is connected to the downstream end of the refrigerant flow direction of the third heat exchanger to form a secondary evaporation; in the heating mode, the second counter-flow heat exchanger is connected to the exhaust end of the compressor, the second counter-flow heat exchanger forms a primary condensation, the third heat exchanger is connected to the downstream end of the refrigerant flow direction of the second counter-flow heat exchanger to form a secondary condensation, the first heat exchanger forms a primary evaporation, and the first counter-flow heat exchanger is connected to the downstream end of the refrigerant flow direction of the first heat exchanger to form a secondary evaporation; thereby effectively achieving dual condensing temperatures and dual evaporating temperatures in a single-stage compression system, thereby effectively reducing the heat exchange temperature difference and reducing the irreversible loss in the heat exchange process, thereby effectively improving the energy efficiency of the system. In addition, the present invention also uses a counter-flow heat exchanger to allow the non-azeotropic working fluid to perform counter-flow heat exchange with water, which can further reduce the heat exchange temperature difference, further reduce the irreversible loss in the heat exchange process, and improve the energy efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 1 is a cycle structure diagram of a single-stage compression air-conditioning system in a cooling mode according to a main embodiment of the present invention;

[0037] Figure 2 1 is a cycle structure diagram of a single-stage compression air-conditioning system in a heating mode according to a main embodiment of the present invention;

[0038] Figure 3 is a cycle structure diagram of a single-stage compression air-conditioning system in cooling mode according to a first alternative embodiment of the present invention;

[0039] Figure 4 is a cycle structure diagram of a single-stage compression air-conditioning system in a heating mode according to a first alternative embodiment of the present invention;

[0040] Figure 5 is a cycle structure diagram of a single-stage compression air-conditioning system in cooling mode according to a second alternative embodiment of the present invention;

[0041] Figure 61 is a cycle structure diagram of a single-stage compression air-conditioning system in heating mode according to a second alternative embodiment of the present invention.

[0042] The reference numerals indicate:

[0043] 10. Compressor; 21. First countercurrent heat exchanger; 22. Second countercurrent heat exchanger; 31. First heat exchanger; 32. Second heat exchanger; 33. Third heat exchanger; 41. First throttling device; 42. Second throttling device; 5. Indoor terminal heat exchanger; 6. Two-way valve; 7. Fan; 80. Four-way valve; C and C tubes; D and D tubes; E and E tubes; S and S tubes; 90. Indoor exhaust duct;

[0044] 101. First pipeline; 102. Second pipeline; 103. Third pipeline; 104. Fourth pipeline; 105. Fifth pipeline; 106. Sixth pipeline; 107. Seventh pipeline; 108. Eighth pipeline; 109. Ninth pipeline; 110. Tenth pipeline; 111. Eleventh pipeline. DETAILED DESCRIPTION

[0045] like Figure 1-6 As shown, the present invention provides a single-stage compression air conditioning system, which includes:

[0046] The compressor 10, the first counterflow heat exchanger 21 (the first counterflow heat exchanger is preferably a shell and tube heat exchanger), the first heat exchanger 31, the second heat exchanger 32, the third heat exchanger 33 and the second counterflow heat exchanger 22 (the second counterflow heat exchanger is preferably a shell and tube heat exchanger), the air-conditioning system includes a non-azeotropic refrigerant consisting of a first boiling point refrigerant and a second boiling point refrigerant, the boiling point of the first boiling point refrigerant is less than the boiling point of the second boiling point refrigerant,

[0047] In cooling mode, the first counterflow heat exchanger 21 is connected to the exhaust end of the compressor 10, and the first counterflow heat exchanger 21 and the first heat exchanger 31 form a primary condensation, or the first counterflow heat exchanger 21 forms a primary condensation alone, and the second heat exchanger 32 is connected to the downstream end of the first heat exchanger 31 in the refrigerant flow direction to form a secondary condensation, or the first heat exchanger 31 and the second heat exchanger 32 are connected in parallel and connected to the downstream end of the first counterflow heat exchanger 21 in the refrigerant flow direction to form a secondary condensation, or the first heat exchanger 31 and the second heat exchanger 32 are connected in series and connected to the downstream end of the first counterflow heat exchanger 21 in the refrigerant flow direction to form a secondary condensation; the third heat exchanger 33 forms a primary evaporation, and the second counterflow heat exchanger 22 is connected to the downstream end of the third heat exchanger 33 in the refrigerant flow direction to form a secondary evaporation;

[0048] In the heating mode, the second counterflow heat exchanger 22 is connected to the exhaust end of the compressor 10, and the second counterflow heat exchanger 22 forms a primary condensation. The third heat exchanger 33 is connected to the downstream end of the refrigerant flow direction of the second counterflow heat exchanger 22 to form a secondary condensation. The first heat exchanger 31 forms a primary evaporation. The first counterflow heat exchanger 21 is connected to the downstream end of the refrigerant flow direction of the first heat exchanger 31 to form a secondary evaporation.

[0049] The present invention introduces at least two non-azeotropic refrigerants into the circulation loop of the single-stage compression air-conditioning system, and sets a first counterflow heat exchanger, a first heat exchanger, a second heat exchanger, a third heat exchanger and a second counterflow heat exchanger in the system, and forms a unique connection mode, which can effectively utilize the temperature glide characteristics of the non-azeotropic refrigerant, and can form a first-stage condensation in the first counterflow heat exchanger and the first heat exchanger in the cooling mode, or the first counterflow heat exchanger forms a first-stage condensation alone, and the second heat exchanger is connected to the downstream end of the refrigerant flow direction of the first heat exchanger to form a second-stage condensation, or the first heat exchanger and the second heat exchanger are connected in parallel to the downstream end of the refrigerant flow direction of the first counterflow heat exchanger to form a second-stage condensation, or the first heat exchanger and the second heat exchanger are connected in series to the first counterflow heat exchanger. The second counter-flow heat exchanger is connected to the downstream end of the refrigerant flow direction of the third heat exchanger to form a secondary condensation; the third heat exchanger forms a primary evaporation, and the second counter-flow heat exchanger is connected to the downstream end of the refrigerant flow direction of the third heat exchanger to form a secondary evaporation; in the heating mode, the second counter-flow heat exchanger is connected to the exhaust end of the compressor, the second counter-flow heat exchanger forms a primary condensation, the third heat exchanger is connected to the downstream end of the refrigerant flow direction of the second counter-flow heat exchanger to form a secondary condensation, the first heat exchanger forms a primary evaporation, and the first counter-flow heat exchanger is connected to the downstream end of the refrigerant flow direction of the first heat exchanger to form a secondary evaporation; thereby effectively achieving dual condensing temperatures and dual evaporating temperatures in a single-stage compression system, thereby effectively reducing the heat exchange temperature difference and reducing the irreversible loss in the heat exchange process, thereby effectively improving the energy efficiency of the system. In addition, the present invention also uses a counter-flow heat exchanger to allow the non-azeotropic working fluid to perform counter-flow heat exchange with water, which can further reduce the heat exchange temperature difference, further reduce the irreversible loss in the heat exchange process, and improve the energy efficiency of the system.

[0050] This invention proposes a novel chilled water multi-split air conditioning system that leverages the characteristics of a high-temperature-glide zeotropic refrigerant, achieving two evaporation and condensation temperatures within a single-stage compression system. Furthermore, the system utilizes countercurrent heat exchange between the zeotropic refrigerant and water, with the water then delivering cooling / heat to the indoor environment through a terminal heat exchanger. This reduces the system's refrigerant charge and mitigates safety risks associated with refrigerant leakage.

[0051] like Figure 1The air-conditioning system shown includes a compressor 10, a first counter-flow heat exchanger 21, a second counter-flow heat exchanger 22, a first heat exchanger 31, a second heat exchanger 32, a third heat exchanger 33, a first throttling device 41, a second throttling device 42, an indoor terminal heat exchanger 5, a two-way valve 6, a fan 7, a four-way reversing valve 80, etc.

[0052] This system cycle uses a non-azeotropic refrigerant with a large slip temperature. The evaporation temperature gradually increases during the evaporation process, and the condensation temperature gradually decreases during the condensation process. Therefore, this feature can be used to divide the evaporator or condenser into two parts during the heat exchange process, so that a high evaporation (condensation) temperature and a low evaporation (condensation) temperature are formed under a certain pressure. In view of this, the present invention proposes a new system cycle, which is divided into a refrigerant circulation flow path and a water circulation flow path.

[0053] In summary, the system of the present invention innovatively applies non-azeotropic refrigerants with large glide temperatures to multi-split chillers, making full use of the temperature glide characteristics of non-azeotropic refrigerants, thereby achieving dual evaporation temperatures and dual condensation temperatures in a single-stage compression system, thereby improving the energy efficiency of the system. During cooling operation, the fresh air is dehumidified and heated in turn, and the supply air temperature can be adjusted to avoid condensation on the indoor terminal heat exchanger and reduce environmental pollution caused by accumulated water; during heating operation, the fresh air temperature can also be preheated to improve the comfort of the supply air and improve the energy efficiency of the system. In addition, the multi-split chiller system can reduce the system filling volume and reduce the safety risks caused by indoor leakage of refrigerants to a certain extent. Making full use of the large glide temperature to produce cold (hot) water of different temperatures, combining it with the whole-house integrated system, or using ground source as the (cold) heat source to save energy, be green and environmentally friendly, conform to the future development direction of green buildings, and have broad prospects.

[0054] In some embodiments, the first pipeline 101, the second pipeline 102, the third pipeline 103, the fourth pipeline 104, the fifth pipeline 105, the sixth pipeline 106 and the first throttling device 41 are included. One end of the first pipeline 101 can be connected to the compressor 10, and the other end is connected to one end of the first countercurrent heat exchanger 21. One end of the second pipeline 102 is connected to the other end of the first countercurrent heat exchanger 21, and the other end of the second pipeline 102 is connected to one end of the first heat exchanger 31. One end of the third pipeline 103 is connected to the other end of the first heat exchanger 31. The other end of the third pipeline 103 is connected to one end of the first throttling device 41, one end of the fourth pipeline 104 is connected to the other end of the first throttling device 41, the other end of the fourth pipeline 104 is connected to one end of the third heat exchanger 33, one end of the fifth pipeline 105 is connected to the other end of the third heat exchanger 33, the other end of the fifth pipeline 105 is connected to one end of the second countercurrent heat exchanger 22, one end of the sixth pipeline 106 is connected to the other end of the second countercurrent heat exchanger 22, and the other end of the sixth pipeline 106 can be connected to the compressor 10.

[0055] This is the preferred structural form of the single-stage compression air-conditioning system of the present invention, that is, the compressor and the first sleeve can be connected for heat exchange through the first pipeline, the first countercurrent heat exchanger and the first heat exchanger can be connected through the second pipeline, the first heat exchanger and the first throttling device can be connected through the third pipeline, the first throttling device can be connected through the fourth pipeline, the third heat exchanger and the second countercurrent heat exchanger can be connected through the fifth pipeline, and the second countercurrent heat exchanger can be effectively connected to the compressor through the sixth pipeline, thereby forming a complete refrigeration cycle loop, which can form primary condensation and secondary condensation, as well as primary evaporation and secondary evaporation on the first countercurrent heat exchanger, the first heat exchanger, the third heat exchanger and the second countercurrent heat exchanger, thereby forming double condensation temperature and double evaporation temperature, effectively utilizing non-azeotropic working fluid to achieve the reduction of heat exchange temperature difference, improve the heat exchange efficiency of the system, and improve energy efficiency.

[0056] like Figure 1-2 , Main embodiment, in some embodiments, in the cooling mode, the first counter-flow heat exchanger 21 and the first heat exchanger 31 form a primary condensation, the second heat exchanger 32 is connected to the downstream end of the first heat exchanger 31 in the refrigerant flow direction to form a secondary condensation, the third heat exchanger 33 forms a primary evaporation, and the second counter-flow heat exchanger 22 is connected to the downstream end of the third heat exchanger 33 in the refrigerant flow direction to form a secondary evaporation;

[0057] In the heating mode, the second counter-flow heat exchanger 22 forms a primary condensation, the third heat exchanger 33 is connected to the downstream end of the refrigerant flow direction of the second counter-flow heat exchanger 22 to form a secondary condensation, the first heat exchanger 31 forms a primary evaporation, and the first counter-flow heat exchanger 21 is connected to the downstream end of the refrigerant flow direction of the first heat exchanger 31 to form a secondary evaporation.

[0058] This is the preferred structural form of the main embodiment of the present invention, that is, in the cooling mode, the first countercurrent heat exchanger and the first heat exchanger are connected in series to form a primary condensation, and the condensation temperature difference between the two is not much different, and a secondary condensation is formed at the second heat exchanger. The secondary condensation and the primary condensation are throttled respectively and then a primary evaporation is performed at the third heat exchanger, and then a secondary evaporation is performed at the second countercurrent heat exchanger, thereby forming a double condensation and double evaporation heat exchange in the cooling mode, reducing the heat exchange temperature difference of each heat exchanger and maximizing the heat exchange efficiency, such as Figure 1 In the heating mode, the second countercurrent heat exchanger forms the first condensation, the third heat exchanger forms the second condensation, the first heat exchanger forms the first evaporation, and the first countercurrent heat exchanger forms the second evaporation, forming the double condensation and double evaporation heat exchange in the heating mode, reducing the heat exchange temperature difference of each heat exchanger and maximizing the heat exchange efficiency. Figure 2 .

[0059] In some embodiments, it also includes a seventh pipeline 107, an eighth pipeline 108, a ninth pipeline 109 and a second throttling device 42, one end of the seventh pipeline 107 is connected to the third pipeline 103, and the other end is connected to one end of the second heat exchanger 32, one end of the eighth pipeline 108 is connected to the other end of the second heat exchanger 32, the other end of the eighth pipeline 108 is connected to one end of the second throttling device 42, one end of the ninth pipeline 109 is connected to the other end of the second throttling device 42, and the other end of the ninth pipeline 109 is connected to the fourth pipeline 104.

[0060] This is a further preferred piping structure of the main embodiment of the present invention, that is, the seventh pipe is connected to the third pipe, and the refrigerant can be introduced into the second heat exchanger for secondary condensation. The refrigerant after the secondary condensation is mixed with the refrigerant that has not undergone the secondary condensation at the fourth pipe through the ninth pipe, and then enters the third heat exchanger together for primary evaporation; in the heating mode, the second throttling device is closed, so that the second heat exchanger is blocked, and the secondary condensation is directly formed through the second countercurrent heat exchanger and the third heat exchanger, and the secondary evaporation is formed by the first heat exchanger and the first countercurrent heat exchanger.

[0061] In some embodiments, the refrigerant in the first countercurrent heat exchanger 21 exchanges heat with the water in the casing in countercurrent flow. The first heat exchanger 31 is an outdoor heat exchanger, and the refrigerant therein exchanges heat with the outdoor air. The third heat exchanger 33 and the second heat exchanger 32 form a heat exchanger group for dehumidifying the indoor space. The refrigerant in the third heat exchanger 33 can cool the air. The air cooled by the third heat exchanger 33 exchanges heat in the second heat exchanger 32 and is heated before entering the indoor space.

[0062] This is a further preferred structural form of the main embodiment of the present invention, that is, the first countercurrent heat exchanger is a structure for countercurrent heat exchange between the refrigerant and the water in the casing, which can further reduce the heat exchange temperature difference and improve the heat exchange efficiency; and the first heat exchanger is an outdoor heat exchanger, which exchanges heat with the outdoor air, and the second heat exchanger and the third heat exchanger form a dehumidification heat exchanger group and can dehumidify the indoor air.

[0063] like Figure 3-4 In a first alternative embodiment, in some embodiments, in the cooling mode, the first counter-flow heat exchanger 21 alone forms a primary condensation, the first heat exchanger 31 and the second heat exchanger 32 are connected in parallel and connected to the downstream end of the first counter-flow heat exchanger 21 in the refrigerant flow direction to form a secondary condensation, the third heat exchanger 33 forms a primary evaporation, and the second counter-flow heat exchanger 22 is connected to the downstream end of the third heat exchanger 33 in the refrigerant flow direction to form a secondary evaporation;

[0064] In the heating mode, the second counter-flow heat exchanger 22 forms a primary condensation, the third heat exchanger 33 is connected to the downstream end of the refrigerant flow direction of the second counter-flow heat exchanger 22 to form a secondary condensation, the first heat exchanger 31 forms a primary evaporation, and the first counter-flow heat exchanger 21 is connected to the downstream end of the refrigerant flow direction of the first heat exchanger 31 to form a secondary evaporation.

[0065] This is the preferred structural form of the first alternative embodiment of the present invention, that is, in the cooling mode, the first countercurrent heat exchanger forms a single primary condensation, and the second heat exchanger and the first heat exchanger form a secondary condensation respectively, which are arranged in parallel. The two secondary condensations are throttled and then perform a primary evaporation in the third heat exchanger, and then perform a secondary evaporation in the second countercurrent heat exchanger, thereby forming a double condensation and double evaporation heat exchange in the cooling mode, reducing the heat exchange temperature difference of each heat exchanger and maximizing the heat exchange efficiency. Figure 3 In the heating mode, the second countercurrent heat exchanger forms the first condensation, the third heat exchanger forms the second condensation, the first heat exchanger forms the first evaporation, and the first countercurrent heat exchanger forms the second evaporation, forming the double condensation and double evaporation heat exchange in the heating mode, reducing the heat exchange temperature difference of each heat exchanger and maximizing the heat exchange efficiency. Figure 4 .

[0066] In some embodiments, it also includes a seventh pipeline 107, an eighth pipeline 108, a ninth pipeline 109 and a second throttling device 42, one end of the seventh pipeline 107 is connected to the second pipeline 102, and the other end is connected to one end of the second heat exchanger 32, one end of the eighth pipeline 108 is connected to the other end of the second heat exchanger 32, the other end of the eighth pipeline 108 is connected to one end of the second throttling device 42, one end of the ninth pipeline 109 is connected to the other end of the second throttling device 42, and the other end of the ninth pipeline 109 is connected to the fourth pipeline 104.

[0067] This is a further preferred piping structure of the first alternative embodiment of the present invention, that is, the seventh pipe is connected to the second pipe, and can introduce refrigerant into the second heat exchanger for secondary condensation. The second pipe can also introduce refrigerant into the first heat exchanger for secondary condensation. The two refrigerants after secondary condensation are mixed at the fourth pipe through the ninth pipe, and after mixing, they enter the third heat exchanger together for primary evaporation; in the heating mode, the second throttling device is closed, so that the second heat exchanger is blocked, and secondary condensation is directly formed through the second countercurrent heat exchanger and the third heat exchanger, and secondary evaporation is formed by the first heat exchanger and the first countercurrent heat exchanger.

[0068] In some embodiments, the refrigerant in the first countercurrent heat exchanger 21 exchanges heat with the water in the casing in countercurrent flow. The first heat exchanger 31 is arranged in the indoor exhaust duct 90 and exchanges heat with the indoor exhaust air to supercool the refrigerant. The third heat exchanger 33 and the second heat exchanger 32 form a heat exchanger group for dehumidifying the room. The refrigerant in the third heat exchanger 33 can cool the air. The air cooled by the third heat exchanger 33 is heated by heat exchange in the second heat exchanger 32 and enters the room.

[0069] This is a further preferred structural form of the first alternative embodiment of the present invention, that is, the first countercurrent heat exchanger is a structure for countercurrent heat exchange between the refrigerant and the water in the casing, which can further reduce the heat exchange temperature difference and improve the heat exchange efficiency; and the first heat exchanger is a heat exchanger arranged in the indoor exhaust air duct, which exchanges heat with the indoor exhaust air, and can effectively utilize the indoor exhaust air to perform supercooling heat exchange on the refrigerant. The second heat exchanger and the third heat exchanger form a dehumidification heat exchanger group and can dehumidify the indoor air.

[0070] like Figure 5-6In a second alternative embodiment, in some embodiments, in the cooling mode, the first counter-flow heat exchanger 21 alone forms a primary condensation, the first heat exchanger 31 and the second heat exchanger 32 are connected in series and connected to the downstream end of the first counter-flow heat exchanger 21 in the refrigerant flow direction to form a secondary condensation, the third heat exchanger 33 forms a primary evaporation, and the second counter-flow heat exchanger 22 is connected to the downstream end of the third heat exchanger 33 in the refrigerant flow direction to form a secondary evaporation;

[0071] In the heating mode, the second counter-flow heat exchanger 22 forms a primary condensation, the third heat exchanger 33 is connected to the downstream end of the refrigerant flow direction of the second counter-flow heat exchanger 22 to form a secondary condensation, the first heat exchanger 31 forms a primary evaporation, and the first counter-flow heat exchanger 21 is connected to the downstream end of the refrigerant flow direction of the first heat exchanger 31 to form a secondary evaporation.

[0072] This is the preferred structural form of the second alternative embodiment of the present invention, that is, in the cooling mode, the first countercurrent heat exchanger forms a single primary condensation, and the second heat exchanger and the first heat exchanger form a secondary condensation respectively. The two are arranged in series, and the refrigerant coming out of the second heat exchanger is throttled and then undergoes a primary evaporation in the third heat exchanger, and then undergoes a secondary evaporation in the second countercurrent heat exchanger, thereby forming a double condensation and double evaporation heat exchange in the cooling mode, reducing the heat exchange temperature difference of each heat exchanger and maximizing the heat exchange efficiency. Figure 5 In the heating mode, the second countercurrent heat exchanger forms the first condensation, the third heat exchanger forms the second condensation, the first heat exchanger forms the first evaporation, and the first countercurrent heat exchanger forms the second evaporation, forming the double condensation and double evaporation heat exchange in the heating mode, reducing the heat exchange temperature difference of each heat exchanger and maximizing the heat exchange efficiency. Figure 6 .

[0073] In some embodiments, it also includes a seventh pipeline 107, an eighth pipeline 108, a ninth pipeline 109 and a second throttling device 42, one end of the seventh pipeline 107 is connected to the third pipeline 103, and the other end is connected to one end of the second heat exchanger 32, one end of the eighth pipeline 108 is connected to the other end of the second heat exchanger 32, the other end of the eighth pipeline 108 is connected to one end of the second throttling device 42, one end of the ninth pipeline 109 is connected to the other end of the second throttling device 42, and the other end of the ninth pipeline 109 is connected to the fourth pipeline 104.

[0074] This is a further preferred piping structure of the second alternative embodiment of the present invention, that is, the seventh pipe is connected to the third pipe, and can introduce refrigerant into the second heat exchanger for secondary condensation. The second pipe can also introduce refrigerant into the first heat exchanger for secondary condensation. The two secondary condensation heat exchangers are connected in series, and the refrigerant after secondary condensation is throttled by the second throttling device and then enters the third heat exchanger for primary evaporation; in the heating mode, the second throttling device is closed, so that the second heat exchanger is blocked, and secondary condensation is directly formed through the second countercurrent heat exchanger and the third heat exchanger, and secondary evaporation is formed by the first heat exchanger and the first countercurrent heat exchanger.

[0075] In some embodiments, the refrigerant in the first countercurrent heat exchanger 21 exchanges heat with the water in the casing in countercurrent flow. The first heat exchanger 31 is arranged in the indoor exhaust duct 90 and exchanges heat with the indoor exhaust air to supercool the refrigerant. The third heat exchanger 33 and the second heat exchanger 32 form a heat exchanger group for dehumidifying the room. The refrigerant in the third heat exchanger 33 can cool the air. The air cooled by the third heat exchanger 33 is heated by heat exchange in the second heat exchanger 32 and enters the room.

[0076] This is a further preferred structural form of the second alternative embodiment of the present invention, that is, the first countercurrent heat exchanger is a structure for countercurrent heat exchange between the refrigerant and the water in the casing, which can further reduce the heat exchange temperature difference and improve the heat exchange efficiency; and the first heat exchanger is a heat exchanger arranged in the indoor exhaust air duct, which exchanges heat with the indoor exhaust air, and can effectively utilize the indoor exhaust air to perform supercooling heat exchange on the refrigerant. The second heat exchanger and the third heat exchanger form a dehumidification heat exchanger group and can dehumidify the indoor air.

[0077] In some embodiments, a tenth pipeline 110, an eleventh pipeline 111, and a four-way valve 80 are further included. The four-way valve 80 includes a C-tube C, a D-tube D, an E-tube E, and an S-tube S. One end of the tenth pipeline 110 is connected to the exhaust port of the compressor 10 and the other end is connected to the D-tube D. The first pipeline 101 is connected between the C-tube C and the first counterflow heat exchanger 21. One end of the eleventh pipeline 111 is connected to the intake port of the compressor 10 and the other end is connected to the S-tube S. The sixth pipeline 106 is connected between the second counterflow heat exchanger 22 and the E-tube E. In cooling mode, the C-tube C is connected to the D-tube D and the S-tube S is connected to the E-tube E. In heating mode, the C-tube C is connected to the S-tube S and the D-tube D is connected to the E-tube E. The present invention also effectively switches between cooling and heating modes through the provision of a four-way valve and multiple pipelines.

[0078] In some embodiments, multiple indoor terminal heat exchangers 5 are arranged in parallel to form a multi-split air conditioning system. Each of the multiple indoor terminal heat exchangers is connected to the second counterflow heat exchanger 22. A brine flows through the indoor terminal heat exchanger 5 and exchanges heat with the refrigerant in the second counterflow heat exchanger 22. The present invention also enables the formation of a multi-split air conditioning water system through the indoor terminal heat exchangers. Water exchanges heat with the refrigerant in the second counterflow heat exchanger before entering the room to cool or heat the room.

[0079] The improvement of the present invention is that when applied to an air conditioning system:

[0080] 1. Different from conventional refrigeration systems, this proposal uses a non-azeotropic refrigerant with a large glide temperature;

[0081] 2. Make full use of the temperature glide characteristics of non-azeotropic working fluids to achieve multiple evaporation temperatures and multiple condensation temperatures in a single-stage system.

[0082] 3. The refrigerant exchanges heat with water in a countercurrent heat exchanger, reducing the irreversible loss in the heat exchange process. The water exchanges heat indoors through the terminal heat exchanger, reducing the amount of refrigerant injected into the system while reducing the safety risks caused by refrigerant leakage into the room.

[0083] 4. The low-temperature evaporator cools and dehumidifies the fresh air to reduce condensation and dripping problems in the indoor unit. The indoor terminal uses a radiant cold plate, dry fan coil or air conditioning cabinet; the low-temperature condenser reheats the fresh air while supercooling, improving the system energy efficiency and the comfort of the air supply.

[0084] 5. Make full use of the large slip temperature to produce cold (hot) water at different temperatures, combine it with the whole house integrated system, or use ground source as the (cold) and heat source to save energy, be green and environmentally friendly, conform to the future development direction of green buildings, and have broad prospects.

[0085] The present invention solves the following technical problems:

[0086] 1. Solve the problem of complex structure of conventional dual-temperature system, and use the temperature glide characteristics of non-azeotropic working fluid to achieve dual condensing temperature and dual evaporating temperature in a single-stage compression system;

[0087] 2. Using a countercurrent heat exchanger allows the non-azeotropic working fluid to exchange heat with water in countercurrent, reducing the heat exchange temperature difference, reducing the irreversible loss in the heat exchange process, and improving the system energy efficiency;

[0088] 3. Solve the safety issues caused by indoor refrigerant leakage in conventional multi-split air conditioning systems;

[0089] 4. Adopt the fresh air air conditioning system mode. The low-temperature evaporator is responsible for the latent heat of the air conditioning, while the sensible heat load is borne by the high-temperature evaporator. The indoor terminal adopts a radiant ceiling, dry fan coil or air conditioning cabinet to solve the environmental pollution problem caused by indoor condensation dripping or water accumulation during cooling of the air conditioning system.

[0090] The present invention has the following beneficial effects:

[0091] 1. The present invention fully utilizes the characteristics of non-azeotropic working fluids with large glide temperatures to achieve dual evaporation temperatures and dual condensation temperatures in a single-stage compression system. At the same time, a countercurrent heat exchanger is used to exchange heat with water, reducing the heat exchange temperature difference, reducing irreversible losses in the heat exchange process, and improving system energy efficiency.

[0092] 2. The refrigerant circulates outdoors, and only water circulates indoors to form a chilled water multi-connected system, which reduces the amount of refrigerant injected while reducing the impact of refrigerant leakage on human safety.

[0093] 3. This air-conditioning system uses a low-temperature evaporator for fresh air dehumidification and high-temperature cooling water for indoor sensible heat load, providing cooling without causing indoor condensation or dripping. The low-temperature condenser reheats the cooled and dehumidified fresh air while supercooling, achieving adjustable air supply temperature, improving system energy efficiency, and enhancing air supply comfort in transitional seasons.

[0094] 4. On the other hand, refrigerants with large glide temperatures produce chilled water or hot water at different temperatures. These cold (hot) water at different temperatures can be used in the whole house integrated system, which is green and environmentally friendly and has broad application prospects in future green buildings.

[0095] The present invention further provides a control method for a single-stage compression air conditioning system as described in any of the preceding items, wherein: when the single-stage compression air conditioning system includes both a first throttling device 41 and a second throttling device 42, the control method includes:

[0096] a judging step of judging whether the operating mode of the single-stage compression air-conditioning system is a cooling mode or a heating mode;

[0097] Control step: when the operating mode is cooling mode, control the first throttling device 41 and the second throttling device 42 to be both opened, or close the first throttling device 41 and open the second throttling device 42 at the same time; when the operating mode is heating mode, control the first throttling device 41 to be opened and close the second throttling device 42 at the same time.

[0098] This is a preferred form of the control method for the single-stage compression air-conditioning system of the present invention, that is, through the control of the first throttling device and the second throttling device, it can achieve the effects of double condensation and double evaporation in the cooling mode and the heating mode respectively, reduce the heat exchange temperature difference of each heat exchanger, improve the heat exchange efficiency, and thus improve the energy efficiency of the system.

[0099] like Figure 1-2 , Main embodiment, in some embodiments, when the single-stage compression air-conditioning system includes a seventh pipeline 107, an eighth pipeline 108, a ninth pipeline 109, and the second throttling device 42, one end of the seventh pipeline 107 is connected to the third pipeline 103, and the other end is connected to one end of the second heat exchanger 32, one end of the eighth pipeline 108 is connected to the other end of the second heat exchanger 32, the other end of the eighth pipeline 108 is connected to one end of the second throttling device 42, one end of the ninth pipeline 109 is connected to the other end of the second throttling device 42, and the other end of the ninth pipeline 109 is connected to the fourth pipeline 104:

[0100] The control step controls both the first throttling device 41 and the second throttling device 42 to be open when the operating mode is the cooling mode, and controls the first throttling device 41 to be open while closing the second throttling device 42 when the operating mode is the heating mode.

[0101] This is the preferred control form of the main embodiment of the present invention, that is, in the cooling mode, both throttling devices are controlled to be open, which can realize the first-stage condensation in the first countercurrent heat exchanger and the first heat exchanger, and the second-stage condensation in the second heat exchanger. Part of the refrigerant that has undergone the second-stage condensation and part of the refrigerant that has not undergone the second-stage condensation are throttled and mixed to enter the third heat exchanger for the first-stage evaporation, and then enter the second countercurrent heat exchanger for the second-stage evaporation, effectively realizing the effects of the second-stage condensation and the second-stage evaporation, and improving the energy efficiency of the system; in the heating mode, the second throttling device is controlled to be closed, and only the first throttling device is used to realize the first-stage and second-stage condensation in the second countercurrent heat exchanger and the third heat exchanger respectively, and the first-stage and second-stage evaporation in the first heat exchanger and the first countercurrent heat exchanger respectively, thereby improving the energy efficiency of the system.

[0102] The specific implementation of the main embodiment of the present invention is as follows:

[0103] 1. When running in cooling mode (such as Figure 1 ), at this time, the four-way reversing valve 80 is de-energized, its D pipe is connected to the C pipe, and the E pipe is connected to the S pipe. The specific operation of the system is as follows:

[0104] Refrigerant cycle: The high-temperature, high-pressure refrigerant discharged from the compressor 10 enters the first countercurrent heat exchanger 21 through the D and C pipes of the four-way reversing valve 80, and performs countercurrent heat exchange with the water in the casing (at this time, the first countercurrent heat exchanger 21 acts as a high-temperature condenser), and then enters the first heat exchanger 31 (at this time, the first heat exchanger 31 acts as a low-temperature condenser). Due to the temperature glide of the non-azeotropic refrigerant, the temperature gradually decreases during the condensation process. Therefore, the average condensation temperature of the first countercurrent heat exchanger 21 is higher than that of the first heat exchanger 31. The refrigerant exiting the first heat exchanger 31 is divided into two paths. One path enters the second heat exchanger 32 for further supercooling, heating the already cooled and dehumidified fresh air, adjusting the supply air temperature and improving the comfort of the supply air, and then passing through the second throttling device 42 for throttling and reducing the pressure. The other path passes through the first throttling device 41 for throttling and reducing the pressure, and then mixes with the refrigerant exiting the second throttling device 42. The mixed refrigerant enters the third heat exchanger 33 (at this time, the third heat exchanger 33 acts as a low-temperature evaporator, and its evaporation temperature is lower than the dew point temperature of the air), cooling and dehumidifying the outdoor fresh air. The refrigerant then enters the second countercurrent heat exchanger 22 (at this time, the second countercurrent heat exchanger 22 acts as a high-temperature evaporator), where the refrigerant further exchanges countercurrent heat with water. (The temperature of the non-azeotropic working fluid gradually increases during the evaporation process, so the average evaporation temperature of the third heat exchanger 33 is lower than that of the second countercurrent heat exchanger 22). After the heat exchange is completed, the refrigerant enters the compressor 10 through the four-way reversing valve 80E and the S pipe, thereby completing the circulation on the refrigerant side.

[0105] Water circulation: On the condensing side, water, under the action of the pump, undergoes countercurrent heat exchange with the high-temperature, high-pressure refrigerant discharged from the compressor 10 in the first countercurrent heat exchanger 21, thereby generating high-temperature hot water, which can be used for bathing and other domestic purposes. Meanwhile, the low-temperature refrigerant from the third heat exchanger 33 undergoes countercurrent heat exchange with water in the second countercurrent heat exchanger 22, generating low-temperature cooling water. This low-temperature cooling water is then transported to the indoor terminal heat exchanger 5 in each room, etc., to cool the room.

[0106] In this mode, the outdoor fresh air is cooled and dehumidified by the third heat exchanger 33 and then reheated by the second heat exchanger 32, reducing the system's supercooling, improving system energy efficiency, and enhancing the comfort of the air supply. The indoor terminal heat exchanger 5 can be a radiant cooling ceiling, a dry fan coil, or an air conditioning cabinet. Multiple indoor terminal heat exchangers 5 form a cold water multi-split air conditioning system. Compared to conventional multi-split systems, this system reduces the amount of refrigerant injected and the risk of refrigerant leaking into the room, greatly improving the safety of system operation. Furthermore, after the fresh air is cooled and dehumidified by the third heat exchanger 33, its moisture content is reduced, making condensation less likely to form on the indoor terminal heat exchanger 5, reducing bacterial growth and environmental pollution caused by water accumulation.

[0107] 2. When the heating mode is running (such as Figure 2), at this time, the four-way reversing valve 80 is energized, the D tube is connected to the E tube, the C tube is connected to the S tube, and the second throttling device 42 is closed (valve closed, no flow). The specific operation mode is as follows:

[0108] Refrigerant cycle: The high-temperature and high-pressure gas discharged from the compressor 10 enters the second countercurrent heat exchanger 22 (at this time, the countercurrent heat exchanger is a high-temperature condenser) through the D and E pipes of the four-way reversing valve 80, countercurrently exchanges heat with the water in the casing (heating the water in the indoor water circulation), and then enters the third heat exchanger 33 for heat exchange with the fresh air (at this time, the third heat exchanger 33 is a low-temperature condenser, which preheats the outdoor fresh air). After the heat exchange is completed, the refrigerant is condensed into liquid, and then enters the outdoor first heat exchanger 31 for heat exchange after throttling and reducing the pressure through the first throttling device 41 (at this time, the first heat exchanger 31 serves as a low-temperature evaporator). The refrigerant coming out of the first heat exchanger 31 enters the first countercurrent heat exchanger 21 for countercurrent heat exchange with water (at this time, the first countercurrent heat exchanger 21 serves as a high-temperature evaporator), and then returns to the suction port of the compressor 10 through the C and S pipes of the four-way reversing valve 80, is compressed and discharged, thereby completing the entire heating cycle.

[0109] Water circulation: The high-temperature, high-pressure refrigerant exchanges heat with water in the second countercurrent heat exchanger 22, heating the water into hot water. This hot water is then delivered to the terminal heat exchangers 5 in each room, providing heat to the room's interior. Any remaining hot water can also be used for domestic purposes such as bathing. In heating mode, the water exchanged with the countercurrent heat exchanger 21 can be drawn from groundwater, meeting normal heating needs.

[0110] In summary, the system of the present invention innovatively applies non-azeotropic refrigerants with large glide temperatures to multi-split chillers, making full use of the temperature glide characteristics of non-azeotropic refrigerants, thereby achieving dual evaporation temperatures and dual condensation temperatures in a single-stage compression system, thereby improving the energy efficiency of the system. During cooling operation, the fresh air is dehumidified and heated in turn, and the supply air temperature can be adjusted to avoid condensation on the indoor terminal heat exchanger and reduce environmental pollution caused by accumulated water; during heating operation, the fresh air temperature can also be preheated to improve the comfort of the supply air and improve the energy efficiency of the system. In addition, the multi-split chiller system can reduce the system filling volume and reduce the safety risks caused by indoor leakage of refrigerants to a certain extent. Making full use of the large glide temperature to produce cold (hot) water of different temperatures, combining it with the whole-house integrated system, or using ground source as the (cold) heat source to save energy, be green and environmentally friendly, conform to the future development direction of green buildings, and have broad prospects.

[0111] like Figure 3-4, first alternative embodiment, in some implementations, when the single-stage compression air-conditioning system includes a seventh pipeline 107, an eighth pipeline 108, a ninth pipeline 109, and the second throttling device 42, one end of the seventh pipeline 107 is connected to the second pipeline 102, and the other end is connected to one end of the second heat exchanger 32, one end of the eighth pipeline 108 is connected to the other end of the second heat exchanger 32, the other end of the eighth pipeline 108 is connected to one end of the second throttling device 42, one end of the ninth pipeline 109 is connected to the other end of the second throttling device 42, and the other end of the ninth pipeline 109 is connected to the fourth pipeline 104:

[0112] The control step controls both the first throttling device 41 and the second throttling device 42 to be open when the operating mode is the cooling mode, and controls the first throttling device 41 to be open while closing the second throttling device 42 when the operating mode is the heating mode.

[0113] This is the preferred control form of the first alternative embodiment of the present invention, that is, in the cooling mode, both throttling devices are controlled to be open, which can realize the first-level condensation of the first countercurrent heat exchanger alone, and the second-level condensation at the first heat exchanger and the second heat exchanger respectively. The two are connected in parallel, and after merging, they enter the third heat exchanger for primary evaporation, and then enter the second countercurrent heat exchanger for secondary evaporation, effectively realizing the effects of secondary condensation and secondary evaporation, and improving the energy efficiency of the system; in the heating mode, the second throttling device is controlled to be closed, and only the first throttling device is used to realize the first-level and second-level condensation at the second countercurrent heat exchanger and the third heat exchanger respectively, and the first heat exchanger and the first countercurrent heat exchanger respectively realize the first-level and second-level evaporation, thereby improving the energy efficiency of the system.

[0114] Figure 3 、 Figure 4 This is the first alternative embodiment of this proposal. Compared to the main embodiment, it adds the function of recovering indoor exhaust air cooling and heat. Specifically, the first heat exchanger 31 is moved into the exhaust duct (the first and second heat exchangers 31 and 32 are connected in parallel). During cooling operation, the system recovers the cooling energy of the indoor exhaust air, further subcooling the refrigerant and improving system energy efficiency. During heating operation, the system recovers the heat of the indoor exhaust air. During cooling operation, both the first and second throttling devices 41 and 42 are open. During heating operation, the second throttling device 42 is closed (no flow), and the first throttling device 41 is open.

[0115] like Figure 5-6In a second alternative embodiment, in some implementations, when the single-stage compression air-conditioning system includes a seventh pipeline 107, an eighth pipeline 108, a ninth pipeline 109, and the second throttling device 42, one end of the seventh pipeline 107 is connected to the third pipeline 103, and the other end is connected to one end of the second heat exchanger 32, one end of the eighth pipeline 108 is connected to the other end of the second heat exchanger 32, the other end of the eighth pipeline 108 is connected to one end of the second throttling device 42, one end of the ninth pipeline 109 is connected to the other end of the second throttling device 42, and the other end of the ninth pipeline 109 is connected to the fourth pipeline 104:

[0116] The control step controls the first throttling device 41 to be closed and the second throttling device 42 to be opened when the operating mode is the cooling mode, and controls the first throttling device 41 to be opened and the second throttling device 42 to be closed when the operating mode is the heating mode.

[0117] This is the preferred control form of the second alternative embodiment of the present invention, that is, in the cooling mode, both throttling devices are controlled to be open, which can realize the first-level condensation of the first countercurrent heat exchanger alone, and the second-level condensation at the first heat exchanger and the second heat exchanger respectively. The two are connected in series, and the refrigerant after coming out of the second heat exchanger enters the third heat exchanger for primary evaporation, and then enters the second countercurrent heat exchanger for secondary evaporation, effectively realizing the effects of secondary condensation and secondary evaporation, and improving the energy efficiency of the system; in the heating mode, the second throttling device is controlled to be closed, and only the first throttling device is used to realize the first-level and second-level condensation at the second countercurrent heat exchanger and the third heat exchanger respectively, and the first heat exchanger and the first countercurrent heat exchanger respectively realize the first-level and second-level evaporation, thereby improving the energy efficiency of the system.

[0118] Figure 5 、 Figure 6 This second alternative embodiment of this proposal, compared to the first alternative embodiment, connects the first and second heat exchangers 31 and 32 in series during cooling operation, leveraging temperature glide to achieve three condensing temperatures and further improve system energy efficiency. During cooling operation, the first throttling device 41 is closed (valve closed, no flow), and the second throttling device 42 is open. During heating operation, the second throttling device 42 is closed (valve closed, no flow), and the first throttling device 41 is open.

[0119] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention. The above description is merely a preferred embodiment of the present invention. It should be noted that those skilled in the art can make various improvements and variations without departing from the technical principles of the present invention, and such improvements and variations shall also be considered within the scope of protection of the present invention.

Claims

1. A single-stage compression air conditioning system, characterized in that: include: A compressor (10), a first counter-flow heat exchanger (21), a first heat exchanger (31), a second heat exchanger (32), a third heat exchanger (33) and a second counter-flow heat exchanger (22), wherein the air-conditioning system comprises a non-azeotropic refrigerant consisting of a first boiling point refrigerant and a second boiling point refrigerant, wherein the boiling point of the first boiling point refrigerant is less than the boiling point of the second boiling point refrigerant, In the cooling mode, the first counter-current heat exchanger (21) is connected to the exhaust end of the compressor (10), the first counter-current heat exchanger (21) and the first heat exchanger (31) form a primary condensation, or the first counter-current heat exchanger (21) forms a primary condensation alone, the second heat exchanger (32) is connected to the downstream end of the refrigerant flow direction of the first heat exchanger (31) to form a secondary condensation, or the first heat exchanger (31) and the second heat exchanger (32) are connected in parallel and connected to the downstream end of the refrigerant flow direction of the first counter-current heat exchanger (21) to form a secondary condensation, or the first heat exchanger (31) and the second heat exchanger (32) are connected in series and connected to the downstream end of the refrigerant flow direction of the first counter-current heat exchanger (21) to form a secondary condensation; the third heat exchanger (33) forms a primary evaporation, and the second counter-current heat exchanger (22) is connected to the downstream end of the refrigerant flow direction of the third heat exchanger (33) to form a secondary evaporation; In the heating mode, the second counter-current heat exchanger (22) is connected to the exhaust end of the compressor (10), the second counter-current heat exchanger (22) forms a first-stage condensation, the third heat exchanger (33) is connected to the downstream end of the refrigerant flow direction of the second counter-current heat exchanger (22) to form a second-stage condensation, the first heat exchanger (31) forms a first-stage evaporation, and the first counter-current heat exchanger (21) is connected to the downstream end of the refrigerant flow direction of the first heat exchanger (31) to form a second-stage evaporation.

2. The single-stage compression air conditioning system according to claim 1, characterized in that: The invention comprises a first pipeline (101), a second pipeline (102), a third pipeline (103), a fourth pipeline (104), a fifth pipeline (105), a sixth pipeline (106) and a first throttling device (41), wherein one end of the first pipeline (101) is connected to the compressor (10), and the other end is connected to one end of the first countercurrent heat exchanger (21), one end of the second pipeline (102) is connected to the other end of the first countercurrent heat exchanger (21), and the other end of the second pipeline (102) is connected to one end of the first heat exchanger (31), one end of the third pipeline (103) is connected to the other end of the first heat exchanger (31), and the third pipeline (105) is connected to the other end of the first heat exchanger (31). The other end of the pipeline (103) is connected to one end of the first throttling device (41), one end of the fourth pipeline (104) is connected to the other end of the first throttling device (41), the other end of the fourth pipeline (104) is connected to one end of the third heat exchanger (33), one end of the fifth pipeline (105) is connected to the other end of the third heat exchanger (33), the other end of the fifth pipeline (105) is connected to one end of the second countercurrent heat exchanger (22), one end of the sixth pipeline (106) is connected to the other end of the second countercurrent heat exchanger (22), and the other end of the sixth pipeline (106) can be connected to the compressor (10).

3. The single-stage compression air conditioning system according to claim 2, characterized in that: In the cooling mode, the first counter-flow heat exchanger (21) and the first heat exchanger (31) form a primary condensation, the second heat exchanger (32) is connected to the downstream end of the first heat exchanger (31) in the refrigerant flow direction to form a secondary condensation, the third heat exchanger (33) forms a primary evaporation, and the second counter-flow heat exchanger (22) is connected to the downstream end of the third heat exchanger (33) in the refrigerant flow direction to form a secondary evaporation; In the heating mode, the second counter-current heat exchanger (22) forms a primary condensation, the third heat exchanger (33) is connected to the downstream end of the refrigerant flow direction of the second counter-current heat exchanger (22) to form a secondary condensation, the first heat exchanger (31) forms a primary evaporation, and the first counter-current heat exchanger (21) is connected to the downstream end of the refrigerant flow direction of the first heat exchanger (31) to form a secondary evaporation.

4. The single-stage compression air conditioning system according to claim 3, characterized in that: The heat exchanger (32) further comprises a seventh pipeline (107), an eighth pipeline (108), a ninth pipeline (109) and a second throttling device (42), wherein one end of the seventh pipeline (107) is connected to the third pipeline (103), and the other end is connected to one end of the second heat exchanger (32), one end of the eighth pipeline (108) is connected to the other end of the second heat exchanger (32), the other end of the eighth pipeline (108) is connected to one end of the second throttling device (42), one end of the ninth pipeline (109) is connected to the other end of the second throttling device (42), and the other end of the ninth pipeline (109) is connected to the fourth pipeline (104).

5. The single-stage compression air conditioning system according to claim 4, characterized in that: The refrigerant in the first countercurrent heat exchanger (21) exchanges heat with the water in the casing in a countercurrent manner. The first heat exchanger (31) is an outdoor heat exchanger, in which the refrigerant exchanges heat with the outdoor air. The third heat exchanger (33) and the second heat exchanger (32) form a heat exchanger group for dehumidifying the indoor space. The refrigerant in the third heat exchanger (33) can cool the air. The air cooled by the third heat exchanger (33) exchanges heat in the second heat exchanger (32) and is heated before entering the indoor space.

6. The single-stage compression air conditioning system according to claim 2, characterized in that: In the cooling mode, the first counter-flow heat exchanger (21) alone forms a primary condensation, the first heat exchanger (31) and the second heat exchanger (32) are connected in parallel and connected to the downstream end of the first counter-flow heat exchanger (21) in the refrigerant flow direction to form a secondary condensation, the third heat exchanger (33) forms a primary evaporation, and the second counter-flow heat exchanger (22) is connected to the downstream end of the third heat exchanger (33) in the refrigerant flow direction to form a secondary evaporation; In the heating mode, the second counter-current heat exchanger (22) forms a primary condensation, the third heat exchanger (33) is connected to the downstream end of the refrigerant flow direction of the second counter-current heat exchanger (22) to form a secondary condensation, the first heat exchanger (31) forms a primary evaporation, and the first counter-current heat exchanger (21) is connected to the downstream end of the refrigerant flow direction of the first heat exchanger (31) to form a secondary evaporation.

7. The single-stage compression air conditioning system according to claim 6, characterized in that: The heat exchanger (32) further comprises a seventh pipeline (107), an eighth pipeline (108), a ninth pipeline (109) and a second throttling device (42), wherein one end of the seventh pipeline (107) is connected to the second pipeline (102), and the other end is connected to one end of the second heat exchanger (32), one end of the eighth pipeline (108) is connected to the other end of the second heat exchanger (32), the other end of the eighth pipeline (108) is connected to one end of the second throttling device (42), one end of the ninth pipeline (109) is connected to the other end of the second throttling device (42), and the other end of the ninth pipeline (109) is connected to the fourth pipeline (104).

8. The single-stage compression air conditioning system according to claim 7, characterized in that: The refrigerant in the first countercurrent heat exchanger (21) exchanges heat with the water in the casing in countercurrent. The first heat exchanger (31) is arranged in the indoor exhaust duct (90) and exchanges heat with the indoor exhaust air to supercool the refrigerant. The third heat exchanger (33) and the second heat exchanger (32) form a heat exchanger group for dehumidifying the room. The refrigerant in the third heat exchanger (33) can cool the air. The air cooled by the third heat exchanger (33) exchanges heat in the second heat exchanger (32) and is heated before entering the room.

9. The single-stage compression air conditioning system according to claim 2, characterized in that: In the cooling mode, the first counter-flow heat exchanger (21) alone forms a primary condensation, the first heat exchanger (31) and the second heat exchanger (32) are connected in series and then connected to the downstream end of the first counter-flow heat exchanger (21) in the refrigerant flow direction to form a secondary condensation, the third heat exchanger (33) forms a primary evaporation, and the second counter-flow heat exchanger (22) is connected to the downstream end of the third heat exchanger (33) in the refrigerant flow direction to form a secondary evaporation; In the heating mode, the second counter-current heat exchanger (22) forms a primary condensation, the third heat exchanger (33) is connected to the downstream end of the refrigerant flow direction of the second counter-current heat exchanger (22) to form a secondary condensation, the first heat exchanger (31) forms a primary evaporation, and the first counter-current heat exchanger (21) is connected to the downstream end of the refrigerant flow direction of the first heat exchanger (31) to form a secondary evaporation.

10. The single-stage compression air conditioning system according to claim 9, characterized in that: The heat exchanger (32) further comprises a seventh pipeline (107), an eighth pipeline (108), a ninth pipeline (109) and a second throttling device (42), wherein one end of the seventh pipeline (107) is connected to the third pipeline (103), and the other end is connected to one end of the second heat exchanger (32), one end of the eighth pipeline (108) is connected to the other end of the second heat exchanger (32), the other end of the eighth pipeline (108) is connected to one end of the second throttling device (42), one end of the ninth pipeline (109) is connected to the other end of the second throttling device (42), and the other end of the ninth pipeline (109) is connected to the fourth pipeline (104).

11. The single-stage compression air conditioning system according to claim 10, characterized in that: The refrigerant in the first countercurrent heat exchanger (21) exchanges heat with the water in the casing in countercurrent. The first heat exchanger (31) is arranged in the indoor exhaust duct (90) and exchanges heat with the indoor exhaust air to supercool the refrigerant. The third heat exchanger (33) and the second heat exchanger (32) form a heat exchanger group for dehumidifying the room. The refrigerant in the third heat exchanger (33) can cool the air. The air cooled by the third heat exchanger (33) exchanges heat in the second heat exchanger (32) and is heated before entering the room.

12. The single-stage compression air conditioning system according to any one of claims 2 to 11, characterized in that: The invention also includes a tenth pipeline (110), an eleventh pipeline (111) and a four-way valve (80), wherein the four-way valve (80) includes a C pipe (C), a D pipe (D), an E pipe (E) and an S pipe (S), and one end of the tenth pipeline (110) is connected to the exhaust end of the compressor (10), and the other end is connected to the D pipe (D), the first pipeline (101) is connected between the C pipe (C) and the first countercurrent heat exchanger (21), and the eleventh pipeline (101) is connected to the exhaust end of the compressor (10). One end of the sixth pipe (106) is connected to the suction end of the compressor (10), and the other end is connected to the S pipe (S). The sixth pipe (106) is connected between the second countercurrent heat exchanger (22) and the E pipe (E). In cooling mode, the C pipe (C) is connected to the D pipe (D) and the S pipe (S) is connected to the E pipe (E). In heating mode, the C pipe (C) is connected to the S pipe (S) and the D pipe (D) is connected to the E pipe (E).

13. The single-stage compression air conditioning system according to any one of claims 2 to 11, characterized in that: It also includes a plurality of indoor terminal heat exchangers (5) arranged in parallel to form a multi-connected air-conditioning system. The plurality of indoor terminal heat exchangers are all connected to the second counter-flow heat exchanger (22). A coolant flows in the indoor terminal heat exchanger (5), and the coolant exchanges heat with the refrigerant in the second counter-flow heat exchanger (22).

14. A control method for a single-stage compression air conditioning system according to any one of claims 2 to 13, characterized in that: When the single-stage compression air conditioning system includes both a first throttling device (41) and a second throttling device (42), the control method includes: a judging step of judging whether the operating mode of the single-stage compression air-conditioning system is a cooling mode or a heating mode; A control step, when the operating mode is a cooling mode, controlling the first throttling device (41) and the second throttling device (42) to be both opened, or closing the first throttling device (41) while opening the second throttling device (42); when the operating mode is a heating mode, controlling the first throttling device (41) to be opened while closing the second throttling device (42).

15. The control method according to claim 14, characterized in that: When the single-stage compression air-conditioning system includes a seventh pipeline (107), an eighth pipeline (108), a ninth pipeline (109) and a second throttling device (42), one end of the seventh pipeline (107) is connected to the third pipeline (103), and the other end is connected to one end of the second heat exchanger (32), one end of the eighth pipeline (108) is connected to the other end of the second heat exchanger (32), the other end of the eighth pipeline (108) is connected to one end of the second throttling device (42), one end of the ninth pipeline (109) is connected to the other end of the second throttling device (42), and the other end of the ninth pipeline (109) is connected to the fourth pipeline (104): The control step controls the first throttling device (41) and the second throttling device (42) to be opened when the operating mode is the cooling mode, and controls the first throttling device (41) to be opened while the second throttling device (42) is closed when the operating mode is the heating mode.

16. The control method according to claim 14, wherein: When the single-stage compression air-conditioning system includes a seventh pipeline (107), an eighth pipeline (108), a ninth pipeline (109) and a second throttling device (42), one end of the seventh pipeline (107) is connected to the second pipeline (102), and the other end is connected to one end of the second heat exchanger (32), one end of the eighth pipeline (108) is connected to the other end of the second heat exchanger (32), the other end of the eighth pipeline (108) is connected to one end of the second throttling device (42), one end of the ninth pipeline (109) is connected to the other end of the second throttling device (42), and the other end of the ninth pipeline (109) is connected to the fourth pipeline (104): The control step controls the first throttling device (41) and the second throttling device (42) to be opened when the operating mode is the cooling mode, and controls the first throttling device (41) to be opened while the second throttling device (42) is closed when the operating mode is the heating mode.

17. The control method according to claim 14, wherein: When the single-stage compression air-conditioning system includes a seventh pipeline (107), an eighth pipeline (108), a ninth pipeline (109) and a second throttling device (42), one end of the seventh pipeline (107) is connected to the third pipeline (103), and the other end is connected to one end of the second heat exchanger (32), one end of the eighth pipeline (108) is connected to the other end of the second heat exchanger (32), the other end of the eighth pipeline (108) is connected to one end of the second throttling device (42), one end of the ninth pipeline (109) is connected to the other end of the second throttling device (42), and the other end of the ninth pipeline (109) is connected to the fourth pipeline (104): The control step controls the first throttling device (41) to be closed and the second throttling device (42) to be opened when the operating mode is the cooling mode, and controls the first throttling device (41) to be opened and the second throttling device (42) to be closed when the operating mode is the heating mode.

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