A heat exchange system

Abstract

The application provides a heat exchange system, comprising a refrigerant composition, and a compressor, a condenser, a throttling element, an evaporator and a first heat exchange device, wherein the refrigerant composition comprises 52wt%-62wt% of 1,1,1,2-tetrafluoroethane, 32wt%-40wt% of difluoromethane and 4wt%-8wt% of carbon dioxide, and the refrigerant composition is a non-azeotropic composition; and the temperature glide of the refrigerant composition is 6.5-10.5 DEG C under the working condition of a condensing temperature of 65 DEG C. The heat exchange system of the application has the temperature glide characteristic due to the use of the non-azeotropic refrigerant composition. The temperature glide enables the refrigerant to gradually evaporate and condense at different temperatures in the evaporator and the condenser, and better matches the temperature gradient of the heat exchanger, thereby improving the heat exchange efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of heat exchange, and in particular relates to a heat exchange system. Background Art

[0002] In modern industry and life, heat exchange systems are widely used in fields such as air conditioners, refrigerators and refrigeration equipment, and play a vital role. Traditional heat exchange systems mainly rely on Freon refrigerants. Although these refrigerants have good refrigeration performance, their negative impact on the environment, such as high global warming potential (GWP) and ozone layer depletion, has led to their gradual restriction and elimination. In recent years, with the increasingly stringent environmental regulations, a variety of alternative refrigerants have emerged on the market. These new refrigerants not only need to have good thermodynamic properties, but also need to ensure the overall efficiency and safety of the system. However, single refrigerants often have various shortcomings in the application process, such as low efficiency and poor stability.

[0003] In a traditional heat exchange system, the compressor, condenser, throttling element, and evaporator are four key components. The compressor is responsible for compressing the refrigerant, increasing its temperature and pressure; the condenser is used to condense the high-temperature, high-pressure refrigerant; the throttling element reduces the pressure of the refrigerant, causing it to enter a low-temperature, low-pressure state; and the evaporator evaporates the low-temperature, low-pressure refrigerant, absorbing heat from the environment. The coordinated work of these components determines the efficiency and performance of the entire heat exchange system. In order to improve the overall efficiency of the system, researchers began to explore the use of a combination of multiple refrigerants to optimize the thermodynamic performance of the heat exchange process. The working principle of the heat exchange system mainly includes four basic processes: compression, condensation, expansion, and evaporation, through which the refrigerant circulation and heat transfer are achieved.

[0004] Traditional heat exchange systems typically rely on a single refrigerant, but these refrigerants present numerous challenges, including ozone depletion. Furthermore, the thermodynamic performance and efficiency of a single refrigerant often fall short of meeting the demands of modern industry and life. Therefore, the question of how to combine refrigerants to develop efficient and environmentally friendly heat exchange systems remains urgent. Summary of the Invention

[0005] The present invention aims to address at least one of the aforementioned technical problems existing in the prior art. To this end, the present invention provides a heat exchange system comprising a plurality of refrigerant compositions in specific proportions to form a non-azeotropic mixture. This heat exchange system design is suitable for low-air-volume heat dissipation or high ambient temperature scenarios. The refrigerant composition can replace R22, has better energy efficiency than R32, and has an ODP (Ozone Depletion Potential) of zero.

[0006] In an embodiment of the first aspect of the present invention, there is provided a heat exchange system comprising a refrigerant composition, and:

[0007] a compressor for compressing the refrigerant composition;

[0008] a condenser connected to the compressor and configured to condense the compressed refrigerant composition;

[0009] a throttling element connected to the condenser and configured to reduce the pressure of the condensed refrigerant composition;

[0010] an evaporator, one end of which is connected to the throttling element and the other end of which is connected to the compressor, for evaporating a low-pressure refrigerant composition;

[0011] a first heat exchange device, wherein the first heat exchange device cools the condenser using a first medium, the condenser comprising a plurality of rows of first heat exchange tubes arranged and sequentially connected along a flow direction of the first medium, the refrigerant composition entering the condenser from the first heat exchange tubes located downstream in the flow direction of the first medium and flowing out of the condenser from the first heat exchange tubes located upstream in the flow direction of the first medium;

[0012] The refrigerant composition comprises, based on the total mass of the refrigerant composition, 52 wt% to 62 wt% of 1,1,1,2-tetrafluoroethane, 32 wt% to 40 wt% of difluoromethane, and 4 wt% to 8 wt% of carbon dioxide. The refrigerant composition is a non-azeotropic composition. Under the operating condition of a condensing temperature of 65°C, the temperature glide of the refrigerant composition is 6.5 to 10.5°C.

[0013] One of the technical solutions of the present invention regarding the heat exchange system has at least the following beneficial effects:

[0014] As will be appreciated, the heat exchange system of the present invention, due to its use of a non-azeotropic refrigerant composition, exhibits a temperature glide characteristic. This temperature glide allows the refrigerant to gradually evaporate and condense at different temperatures in the evaporator and condenser, better matching the temperature gradient of the heat exchanger and thereby improving heat exchange efficiency.

[0015] Furthermore, since the refrigerant composition can more effectively utilize the temperature glide characteristics during the evaporation and condensation processes, when used in conjunction with a countercurrent heat exchanger, it can reduce irreversible losses during the heat exchange process, thereby improving the energy efficiency of the system and reducing energy consumption.

[0016] Structurally, the condenser is designed with multiple rows of heat exchange tubes, and the refrigerant composition has good performance under the condition of condensation temperature of 65°C, which enables the heat exchange system to work effectively in high temperature environment, has strong adaptability, and can still maintain efficient operation under conditions of high ambient temperature. The first heat exchange device uses the first medium (such as air) to cool the condenser, and the heat exchange tubes downstream and upstream of the air flow direction are connected in sequence, which optimizes the cooling process. This design allows effective cooling at lower air volume and is suitable for air volume less than 500m 3 / h scenario, saving energy while improving condensation efficiency. Furthermore, the condenser design with multiple rows of first heat exchange tubes provides a larger heat exchange area within a smaller volume, helping to reduce the overall size and weight of the system. This is a significant advantage for applications with limited installation space, such as mobile air conditioning equipment or small cooling devices.

[0017] In addition, the refrigerant composition of the present invention should be of full grade A1 or A2L. The refrigerant composition is a non-azeotropic composition, which can boil or condense in a wide temperature range under constant pressure conditions, thereby generating temperature glide in the evaporator or condenser. Since the non-azeotropic mixed refrigerant has temperature glide during phase change, it can cooperate with the temperature gradient of the cooling medium to achieve better heat exchange. This feature, combined with a multi-row countercurrent heat exchanger, can reduce irreversible losses in the heat exchange process. The refrigerant composition of the present invention is suitable for small air volume (heat dissipation air volume less than 500m 3 / h) heat dissipation or high ambient temperature (above 35°C) scenarios.

[0018] Specifically: The safety level of the refrigerant composition is A1 or A2L, which means it is a low-toxic, non-flammable or low-flammable refrigerant with low safety risks to humans and the environment, and is suitable for various application scenarios.

[0019] The refrigerant composition is non-azeotropic, meaning its components can boil or condense independently under certain conditions, rather than forming a fixed boiling point. This property allows the refrigerant to experience temperature glide in the evaporator or condenser, helping to reduce irreversible losses during the heat exchange process.

[0020] The temperature glide characteristics of the refrigerant composition can be combined with multiple rows of counter-flow heat exchangers to help reduce irreversible losses in the heat exchange process. This means that the system loses less energy during the energy conversion process, thereby improving the energy efficiency of the system.

[0021] The refrigerant composition also has a relatively high condensing temperature, which is above 52°C, for example, above 65°C. When the condenser's heat dissipation air volume is small, due to the large temperature difference between the condenser and the ambient temperature, a small air volume can also achieve a good heat dissipation effect of the condenser, thereby increasing the cooling capacity. When used in a high-temperature environment, the condenser and the ambient temperature still maintain a certain temperature difference, which can achieve high-temperature cooling.

[0022] In the refrigerant composition of the present invention, since both R134a (i.e., 1,1,1,2-tetrafluoroethane) and R744 (i.e., CO2) are non-flammable, the flammability of the mixed refrigerant is lower than that of R32 (i.e., difluoromethane).

[0023] Taking all of these advantages into account, the refrigerant composition of the present invention can improve system energy efficiency when used in low-air-volume heat dissipation scenarios and high ambient temperatures. By reducing energy losses, the system can achieve more efficient cooling, reducing energy consumption and lowering operating costs. The refrigerant composition of the present invention also has the advantage of low toxicity or low flammability.

[0024] According to some embodiments of the present invention, the number of the first heat exchange tubes is at least 2 rows, preferably at least 3 rows, and more preferably 4 to 10 rows.

[0025] Increasing the number of rows of the first heat exchange tubes significantly increases the condenser's heat transfer area. More rows of heat exchange tubes provide a larger contact area, enabling more complete heat exchange between the refrigerant and the first medium, improving overall heat exchange efficiency. More rows of heat exchange tubes enable temperature glide over a longer heat exchange path, better matching the cooling medium's temperature gradient. This optimizes the refrigerant's phase change process and reduces heat loss caused by temperature fluctuations.

[0026] In addition, by increasing the number of rows of heat exchange tubes, efficient heat exchange can be achieved in a wider range of condensing temperature, especially under high ambient temperature conditions (above 35°C). The design of more rows of heat exchange tubes enables the condenser to maintain good condensation effect under high temperature conditions, ensuring the cooling capacity and stability of the system. Under low air volume heat dissipation conditions (heat dissipation air volume less than 500m 3 / h), more rows of heat exchange tubes can ensure the condenser's heat dissipation through a larger heat exchange area and more efficient countercurrent heat exchange. This allows the system to operate efficiently even under low air volume conditions and adapt to a wider range of practical application scenarios. The design of multiple rows of countercurrent heat exchange tubes gradually cools the refrigerant in stages, effectively reducing irreversible losses in the heat exchange process. More rows of heat exchange tubes enable the condenser to exchange heat more stably under different operating conditions, reducing the mechanical and thermal stresses caused by temperature fluctuations. This enhances system reliability and reduces failure rates and maintenance costs. As a result, the flexible design of the number of heat exchange tube rows enables the heat exchange system to adapt to a variety of different application requirements, providing efficient cooling solutions for applications ranging from low air volume heat dissipation to high-temperature environments. This gives the system a wider market adaptability and application prospects.

[0027] According to some embodiments of the present invention, the first medium includes air, and the wind volume generated by the air flow is less than 500m 3 / h.

[0028] Lower air flow rates mean that the heat exchange system requires less fan power during operation, reducing energy consumption. This helps lower the system's overall energy consumption and saves operating costs. Low-volume air flow generates less noise, significantly reducing system operating noise. This is a significant advantage for applications requiring a quiet environment, such as home air conditioning, offices, and hospitals, enhancing the user experience. Lower air volumes reduce fan load and wear, extending the service life of the fan and other related components, reducing equipment maintenance and replacement costs, and improving the long-term reliability and cost-effectiveness of the system.

[0029] Furthermore, the low air volume design enables the heat exchange system to operate efficiently in environments with limited space or poor ventilation. For example, even in high-temperature environments (above 35°C), the system can still achieve effective heat exchange with relatively low air volumes, ensuring cooling effectiveness. This makes the system more adaptable to a wider range of practical application scenarios. Despite the low air volume, by increasing the number of rows of the first heat exchange tubes (preferably 4 to 10 rows), the condenser's heat transfer area is expanded, fully utilizing the low air volume for effective heat exchange. The counterflow design and temperature glide characteristics further optimize the condensation process, improving heat exchange efficiency and system performance. Using low air volumes as the cooling medium reduces environmental impact, aligning with environmental protection and sustainable development. Furthermore, the system's efficient operation and low energy consumption also help reduce carbon emissions and protect the environment. The lower air flow requirement allows for the use of smaller fans and ventilation equipment, reducing initial equipment procurement and installation costs. This is particularly beneficial for small cooling systems or applications with limited budgets.

[0030] According to some embodiments of the present invention, the first heat exchange device further includes an exhaust pipe, wherein the exhaust pipe is used to discharge the air, and the diameter of the exhaust pipe is ≤120 mm.

[0031] The exhaust duct has a small diameter (≤120mm), making the entire system more compact. This allows for more flexible layout and installation in space-constrained environments, such as small computer rooms and home air conditioning systems, saving valuable space.

[0032] According to some embodiments of the present invention, the heat exchange system further includes a second heat exchange device, which utilizes a second medium to exchange heat with the evaporator. The evaporator includes a plurality of rows of second heat exchange tubes arranged and sequentially connected along the flow direction of the second medium. The refrigerant composition enters the evaporator from the second heat exchange tubes located downstream in the flow direction of the second medium and flows out of the evaporator from the second heat exchange tubes located upstream in the flow direction of the second medium.

[0033] By utilizing multiple rows of secondary heat exchange tubes and adopting a countercurrent heat exchange design, heat from the secondary medium can be more efficiently transferred to the refrigerant composition. This maximizes the temperature difference between the two, improving heat exchange efficiency and thus enhancing the cooling capacity and performance of the entire system. The temperature glide characteristic of the non-azeotropic refrigerant composition during evaporation, combined with the countercurrent heat exchange design, ensures a more efficient heat exchange process. This temperature glide better matches the temperature gradient of the secondary medium, reducing irreversible losses during the heat exchange process and further improving the system's energy efficiency. Furthermore, the multiple rows of heat exchange tubes increase the heat transfer area of ​​the evaporator, allowing the refrigerant sufficient time and area within the evaporator to complete the heat exchange process. This not only improves the refrigerant's evaporation efficiency but also ensures that the evaporator provides stable cooling under various operating conditions. The multiple rows of heat exchange tubes help evenly distribute the heat load, reducing the load and stress on individual heat exchange tubes. This reduces equipment damage caused by overheating or localized undercooling, thereby improving the overall reliability and service life of the system. The design of the heat exchange system of the present invention can accommodate different types of secondary media, such as water, air, or other liquid cooling media, making the system more widely applicable. Whether used in industrial cooling, air conditioning systems, or specialized environments, the system operates efficiently to meet diverse cooling needs. By optimizing the heat exchange process and reducing irreversible losses, the system achieves efficient cooling with lower energy consumption. This not only reduces energy consumption and operating costs, but also meets current energy conservation and environmental protection requirements, helping to reduce carbon emissions and environmental impact. The multi-row heat exchange tube design enables better control of the refrigerant flow path and heat exchange process, ensuring stable system operation under varying loads and operating conditions. This improves the system's control accuracy and response speed, meeting the dynamic needs of diverse application scenarios.

[0034] According to some embodiments of the present invention, the number of the second heat exchange tubes is at least 2 rows, preferably 2 to 10 rows.

[0035] Increasing the number of rows of secondary heat exchange tubes significantly increases the evaporator's heat transfer area, thereby improving heat exchange efficiency. Designing with a minimum of two to ten rows of heat exchange tubes provides greater system flexibility and adjustability. The number of heat exchange tubes can be flexibly adjusted based on actual needs and application scenarios to best meet user requirements.

[0036] According to some embodiments of the present invention, the condenser is designed to operate under the condition that the ambient temperature is higher than 35°C.

[0037] In high-temperature environments, the performance and stability of refrigeration systems are particularly important. By designing the condenser to operate in high-temperature environments, we can improve system performance and enhance user experience and satisfaction.

[0038] According to some embodiments of the present invention, the mass percentage of 1,1,1,2-tetrafluoroethane can be, for example, 52 wt%, 52.5 wt%, 53 wt%, 53.5 wt%, 54 wt%, 54.5 wt%, 55 wt%, 55.5 wt%, 56 wt%, 56.5 wt%, 57 wt%, 57.5 wt%, 58 wt%, 58.5 wt%, 59 wt%, 59.5 wt%, 60 wt%, 60.5 wt%, 61 wt%, 61.5 wt%, or 62 wt%, or a range value formed by any two of them.

[0039] According to some embodiments of the present invention, the mass percentage of difluoromethane can be, for example, 32wt%, 32.5wt%, 33wt%, 33.5wt%, 34wt%, 34.5wt%, 35wt%, 35.5wt%, 36wt%, 36.5wt%, 37wt%, 37.5wt%, 38wt%, 38.5wt%, 39wt%, 39.3wt%, or 40wt%, or a range value formed by any two of them.

[0040] According to some embodiments of the present invention, the mass percentage of carbon dioxide can be, for example, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt%, 5.5wt%, 6wt%, 6.5wt%, 7wt%, 7.5wt%, 8wt% or any value in the range formed by any two of them.

[0041] According to some embodiments of the present invention, the refrigerant composition comprises: 58 wt%-62 wt% of 1,1,1,2-tetrafluoroethane, 32 wt%-36 wt% of difluoromethane, and 4 wt%-7 wt% of carbon dioxide.

[0042] Selecting the above refrigerant composition can make the refrigerant safety level reach A1, further reduce the exhaust temperature and condensing pressure, and increase the relative volume cooling capacity and temperature glide, which is more suitable for scenarios with small air volume heat dissipation or high ambient temperature.

[0043] According to some embodiments of the present invention, under the operating conditions of an evaporating temperature of 13° C. and a condensing temperature of 65° C., the exhaust temperature of the refrigerant composition is less than 107.5° C. and the condensing pressure is less than 3.7 MPa.

[0044] The condensing temperature of the refrigerant composition is defined as the average value of the dew point temperature and the bubble point temperature at the corresponding pressure (condensing pressure); the evaporating temperature of the refrigerant composition is defined as the average value of the dew point temperature and the bubble point temperature at the corresponding pressure (evaporating pressure).

[0045] Lower exhaust gas temperature and condensing pressure generally mean that the system operates in a more stable state. This can reduce the system failure rate and reduce the need for maintenance and repair in the long run.

[0046] Additionally, under given operating conditions, a higher temperature glide means the refrigerant better matches the air temperature during the phase change heat transfer process, which helps improve the system's energy efficiency.

[0047] According to some embodiments of the present invention, the safety level of the refrigerant composition reaches A1; under the operating conditions of an evaporating temperature of 13°C and a condensing temperature of 65°C, the exhaust temperature is less than 105°C, the condensing pressure is less than 3.6 MPa, the relative volumetric cooling capacity is above 115%, and the temperature glide is greater than 7°C.

[0048] A safety rating of A1 indicates the refrigerant is low-toxic and non-flammable, posing minimal risks to humans and the environment, making it suitable for safe use in a variety of scenarios and reducing safety hazards and usage restrictions. The exhaust temperature is less than 105°C. This lower exhaust temperature reduces the heat load on the compressor and other components, lowering the risk of equipment failure due to overheating, thereby improving system stability and reliability. The condensing pressure is less than 3.6 MPa. This lower condensing pressure reduces mechanical and thermal stress on the system, extending equipment life and reducing the frequency and cost of maintenance and replacement. The relative volumetric cooling capacity is above 115%. This high relative volumetric cooling capacity indicates higher cooling capacity within the same volume, improving the system's energy efficiency ratio (COP), reducing energy consumption, and lowering operating costs. The temperature glide is greater than 7°C. This temperature glide characteristic allows the refrigerant to better match the temperature gradient of the heat exchanger during evaporation and condensation, optimizing heat transfer and further enhancing heat exchange efficiency and overall system performance. Therefore, due to its high safety rating and excellent performance parameters, this refrigerant is suitable for a variety of commercial, industrial, and domestic applications, especially under high-temperature and high-load conditions.

[0049] According to some embodiments of the present invention, the condenser is a straight heat exchanger, which includes multiple rows of first heat exchange tubes, which are arranged in sequence along the air flow direction and connected in series in sequence, and the number of rows of first heat exchange tubes is at least 4 rows.

[0050] The design of multiple rows of first heat exchange tubes increases the heat exchange area of ​​the condenser, allowing more heat to be transferred to the air. This helps to improve heat exchange efficiency, allowing the refrigerant to dissipate heat faster during the condensation process, thereby improving the cooling performance of the system.

[0051] The straight heat exchanger design allows air to flow sequentially through multiple rows of heat exchange tubes, increasing the contact area between the air and the refrigerant, thereby improving heat dissipation efficiency. This helps transfer heat from the refrigerant to the air in a shorter time, improving the condenser's heat dissipation capacity.

[0052] Multiple rows of heat exchange tubes are arranged sequentially along the air flow direction and connected in series, allowing for gradual heat transfer and a more uniform and stable heat exchange process. This helps avoid heat competition between tubes, reduces local overheating or undercooling, and optimizes the heat exchange process. The multi-row design also distributes heat more evenly within the condenser, reducing the load and stress on the tubes and the risk of equipment damage caused by overheating or localized undercooling. This helps improve system stability and reliability, extending equipment life.

[0053] The straight heat exchanger design is suitable for operating conditions in high-temperature environments and can better adapt to high ambient temperature requirements. This allows the system to maintain stable heat dissipation in high-temperature environments, improving system reliability and adaptability. As you can understand, the straight heat exchanger's compact structure and small footprint make it suitable for installation environments with limited space. This helps simplify system layout and installation, saving installation space and costs.

[0054] According to some embodiments of the present invention, the condenser is provided with a plurality of pipelines in parallel, each pipeline flowing through each row of first heat exchange tubes; for each pipeline, the refrigerant composition enters the pipeline from the first heat exchange tube located downstream in the flow direction of the first medium, and flows out of the pipeline from the first heat exchange tube located upstream in the flow direction of the first medium.

[0055] Multiple parallel pipes distribute the refrigerant flow, with each pipe flowing through all heat exchanger tube banks. This ensures uniform refrigerant flow within the condenser, avoiding localized overcooling or overheating and achieving more uniform temperature distribution. Furthermore, the multi-pipe parallel design effectively reduces flow resistance within individual pipes, lowering system pressure drop, thereby reducing compressor workload and improving the overall system's energy efficiency ratio (COP). Furthermore, even if a single pipe becomes clogged or experiences other problems, the multi-pipe parallel design does not completely impact the operation of the entire condenser, ensuring continued system operation and enhanced reliability and stability. Furthermore, the countercurrent heat exchange method better utilizes temperature gradients, improving heat transfer efficiency. This is particularly important for applications requiring precise temperature control, such as industrial cooling processes. Furthermore, the multi-pipe parallel design enables the condenser to adapt to varying operating conditions and load variations, ensuring efficient operation under a wide range of operating conditions. The condenser maintains excellent performance, whether operating at partial or full load. This improved heat exchange efficiency and reduced pressure drop significantly reduces overall system energy consumption and operating costs. At the same time, it extends the service life of the equipment, reduces the frequency of repairs and replacements, and further reduces the total cost of ownership.

[0056] According to some embodiments of the present invention, the heat exchange system further includes an electronic control box, which includes a control panel and a cooling pipe for dissipating heat from the control panel; one of the multiple pipelines is connected in series with a cooling pipe for electronically controlled heat dissipation, and the refrigerant composition returns to the condenser after passing through the cooling pipe and is cooled by the first medium.

[0057] Cooling pipes dissipate heat from the control panel in the electronic control box, ensuring it maintains a suitable temperature during operation, preventing control system failures caused by overheating and improving control system reliability and stability. Connecting the heat dissipation system in series with the refrigeration system's condenser eliminates the need for a separate cooling system, enabling integrated system design, simplifying the system architecture, and reducing equipment size and installation space. After dissipating heat from the electronic control box in the cooling pipes, the refrigerant returns to the condenser, carrying some of the heat with it, where it is cooled by a primary medium (such as air). This effectively utilizes the refrigerant's waste heat and improves overall system energy efficiency. The dual heat dissipation pathways of the cooling pipes and condenser allow for more efficient heat dissipation from the refrigerant, reducing compressor load and improving the system's Energy Efficiency Ratio (COP), thereby reducing energy consumption and operating costs. Maintaining a low operating temperature for the control panel reduces damage to electronic components caused by high temperatures, extending the service life of the control panel and the entire electronic control system, and reducing the frequency and cost of repairs and replacements. Using the refrigerant to dissipate heat from the electronic control box prevents localized overheating, ensuring stable system operation even under high loads and high temperatures, and enhancing overall system reliability.

[0058] According to some embodiments of the present invention, the evaporator is a U-shaped evaporator, comprising at least two rows of U-shaped second heat exchange tubes, and multiple rows of first heat exchange tubes are sequentially arranged along the air flow direction and sequentially connected in series.

[0059] The evaporator uses at least two rows of U-shaped secondary heat exchange tubes, effectively increasing the heat exchange area and allowing more heat to be transferred to the refrigerant. This helps improve heat exchange efficiency, allowing the evaporator to more fully absorb heat from the air.

[0060] According to some embodiments of the present invention, the evaporator is an integrated evaporator, including a shell, a condenser, a compressor, and a throttling device, all of which are located inside the shell. The shell has an inwardly concave clearance groove, which is used to cooperate with the ceiling keel so that the shell is at least partially located above the ceiling.

[0061] According to some embodiments of the present invention, the heat exchange system is an integrated air conditioner, which includes a shell, and the compressor, the condenser, the throttling element and the evaporator are located in the shell and are interconnected by a refrigerant pipe.

[0062] The integration of all major components within a single housing simplifies the installation of the air conditioning system. Users only need to install one complete unit, eliminating the need to install and connect multiple components individually, saving installation time and labor costs. The integrated design also simplifies system maintenance, as users only need to handle one unit, rather than multiple separate components. By integrating all components within a single housing, the integrated design reduces the required installation space. This is particularly beneficial in environments with limited space, such as small rooms or vehicle interiors. Furthermore, the use of fewer pipes and fittings is reduced, further saving space. Furthermore, since all major components are integrated within a single housing and interconnected by refrigerant piping, fewer connection points are required in the refrigerant piping system, reducing the risk of refrigerant leaks. This contributes to improved system stability and reliability. Furthermore, the integrated design reduces piping length and connection points, reducing refrigerant pressure loss and flow resistance in the piping, thereby improving overall system efficiency. Furthermore, the integrated design optimizes heat exchange between components, further enhancing system energy efficiency. The integrated design also results in a cleaner and more aesthetically pleasing air conditioning system, eliminating the need for additional piping and fittings, reducing clutter. This has a significant improvement effect on some occasions with high requirements on appearance, such as homes, commercial places or vehicle interiors.

[0063] According to some embodiments of the present invention, the integrated air conditioner is located indoors, and the condenser is connected to the outdoors through an exhaust pipe.

[0064] According to some embodiments of the present invention, the integrated air conditioner is ceiling mounted and is at least partially located above the indoor ceiling.

[0065] Because packaged air conditioners are partially or completely installed above the ceiling, they effectively conserve available indoor space. This is particularly beneficial in spaces with limited space, such as commercial spaces, offices, or residences. Ceiling installation allows the components of packaged air conditioners to be completely concealed above the ceiling, creating a cleaner and more aesthetically pleasing interior. This improves the quality and comfort of interior decor, creating a more comfortable indoor environment. Installing the main components of the air conditioner above the ceiling effectively reduces noise disturbance during operation. This is particularly beneficial in locations requiring a quiet environment, such as offices, conference rooms, or bedrooms. Ceiling installation allows the main components of the air conditioner to be located above the ceiling, making it easier to maintain and clean. This allows easier access and operation for maintenance personnel, reducing maintenance and extending the life of the equipment. Because packaged air conditioners are partially or completely installed above the ceiling, they can more effectively and evenly distribute cool air to every corner of the room, improving cooling or heating performance. This helps ensure comfortable indoor air quality and temperature uniformity. Ceiling installation also effectively protects the air conditioner from external objects and damage, improving its safety and reliability. This helps reduce accidental damage and repair costs, ensuring the safety of equipment and users.

[0066] According to some embodiments of the present invention, the integrated air conditioner is a kitchen air conditioner, a bathroom air conditioner or a mobile air conditioner. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 It is a temperature entropy diagram of the refrigerant composition and a schematic diagram of the wind temperature changes.

[0068] Figure 2 It is a schematic diagram of the air conditioning structure of the first embodiment of the heat exchange system of the present invention.

[0069] Figure 3 Schematic diagram of a refrigerant circulation system of a first embodiment of a heat exchange system of the present invention.

[0070] Figure 4 This is a flow diagram of the condenser of the first embodiment of the heat exchange system of the present invention.

[0071] Figure 5 It is a schematic diagram of the air conditioning installation structure of the second embodiment of the heat exchange system of the present invention.

[0072] Figure 6 It is a schematic structural diagram of the air conditioner according to the second embodiment of the heat exchange system of the present invention, when viewed from a certain top view, with the casing removed.

[0073] Figure 7 It is a horizontal cross-sectional bottom view of the second embodiment of the heat exchange system of the present invention.

[0074] Figure 8This is a flow diagram of a condenser according to the second embodiment of the heat exchange system of the present invention.

[0075] Reference numerals:

[0076] 100: host; 200: return air outlet; 300: exhaust duct; 400: supply air duct; 500: outlet;

[0077] 110: evaporator; 120: gas-liquid separator; 130: compressor; 140: condenser; 150: throttling element; 160: supply fan; 170: exhaust fan;

[0078] 1000: kitchen air conditioner; 1001: housing; 1002: first fan; 1003: first heat exchanger;

[0079] 1004: second fan; 1005: second heat exchanger; 1006: compression device; 1009: refrigerant pipe;

[0080] 1014: clearance groove; 1051: first pipeline; 1052: second pipeline;

[0081] 1101: first air inlet; 1103: second air inlet; 1104: second air outlet; 1110: first cavity; 1120: second cavity;

[0082] 2000: Ceiling; 2100: Keel; 2200: Spliced ​​decorative panels. DETAILED DESCRIPTION

[0083] The following are specific embodiments of the present invention, and the technical solutions of the present invention are further described in conjunction with the embodiments, but the present invention is not limited to these embodiments.

[0084] The following will clearly and completely describe the concept and technical effects of the present invention in conjunction with the embodiments to fully understand the purpose, features and effects of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0085] In the description of the present invention, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the exemplary expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0086] Unless otherwise specified, "room temperature" in the present invention means 25°C±5°C.

[0087] Unless otherwise specified, “about” in the present invention means that the allowable error is within ±1%.

[0088] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or those recommended by the manufacturer. All reagents or instruments used, if the manufacturer is not specified, are commercially available conventional products.

[0089] The relevant information of some refrigerants is shown in Table 1.

[0090] Table 1

[0091] Chemical formula Critical temperature / ℃ Critical pressure / MPa Security Level R134a <![CDATA[CH2FCF3]]> 101.1 4.06 A1 R32 <![CDATA[CH2F2]]> 78.11 5.78 A2L R744 <![CDATA[CO2]]> 30.98 7.38 A1 R22 <![CDATA[CHClF2]]> 96.14 4.99 A1

[0092] Examples 1 to 31

[0093] Examples 1 to 31 provide refrigerant compositions that are mixtures of R134a, R32, and R744. The mass percentages of R134a:R32:R744, based on the total mass of the refrigerant composition, are shown in Table 2.

[0094] Effect test

[0095] The mixed refrigerants of Examples 1 to 31, R22, and R32 were selected for theoretical cycle calculation.

[0096] The selected working conditions are: evaporating temperature 13°C, condensing temperature 65°C (for mixed refrigerants, evaporating temperature and condensing temperature are defined by the average value of dew point and bubble point under a certain pressure), superheat 2°C, subcooling 10°C, and compressor isentropic efficiency 0.7.

[0097] Refrigerant properties were obtained using REFPROP software. Comparisons were made of volumetric cooling capacity, energy efficiency (EER), condensing pressure, pressure ratio, temperature glide (at condensing pressure), and exhaust temperature. The relative values ​​in the calculations were based on R22.

[0098] The results are shown in Table 2.

[0099] Table 2

[0100]

[0101]

[0102] From the results in Table 2, it can be seen that although R32 has a significantly higher relative volumetric cooling capacity than R22, the condensing pressure and exhaust temperature are very high when the system is running, which is not conducive to equipment reliability, and the energy efficiency is reduced by about 7%.

[0103] For the refrigerant compositions of the present invention, the relative volumetric cooling capacity of all examples exceeded that of R22, exceeding 115% of that of R22. The relative energy efficiency was only slightly lower than that of R22, but the difference was within 4%. The condensing pressure was lower than that of R32 and slightly higher than that of R22, with a pressure ratio essentially the same as that of R22.

[0104] By comparing different embodiments, we can find that:

[0105] According to the test results of Examples 1, 6, 10, and 16, by keeping the R32 ratio unchanged and increasing the CO2 ratio (correspondingly reducing the R134a ratio), the refrigerant composition shows a trend of increasing relative volumetric cooling capacity, decreasing relative pressure ratio, and increasing temperature glide.

[0106] According to the test results of Examples 10, 15, 21, 25, and 29, by keeping the CO2 ratio unchanged and increasing the R32 ratio (correspondingly reducing the R134a ratio), the refrigerant composition shows a trend of increasing volumetric refrigeration capacity and slightly decreasing relative pressure ratio. Compared with the case where CO2 replaces R134a, the changes in various indicators are smaller.

[0107] According to the test results of Examples 7 to 10, by keeping the R134a ratio unchanged and increasing the R32 ratio (correspondingly reducing the CO2 ratio), the refrigerant composition shows a trend of decreasing condensing pressure and exhaust gas temperature.

[0108] The above test results show that changes in the amounts of different components in the refrigerant composition of the present invention will have different degrees of impact on the relative volumetric cooling capacity, relative refrigeration energy efficiency, condensing pressure, relative pressure ratio, temperature glide, exhaust temperature, etc. of the heat exchange system.

[0109] To replace R22 without increasing the system pressure and exhaust temperature as much as R32, the refrigerant composition may be composed of 52 wt%-62 wt% of 1,1,1,2-tetrafluoroethane, 32 wt%-40 wt% of difluoromethane, and 4 wt%-8 wt% of carbon dioxide.

[0110] In order to stably maintain the safety level of the refrigerant composition to A1 under the operating conditions of an evaporating temperature of 13°C and a condensing temperature of 65°C, the exhaust temperature is less than 105°C, the condensing pressure is less than 3.6 MPa, the relative volumetric cooling capacity is above 115%, and the temperature glide is greater than 7°C, so as to better meet the system reliability requirements and the heat exchange requirements of small exhaust volume and high temperature working environment, the refrigerant composition can be composed of 58wt%-62wt% of 1,1,1,2-tetrafluoroethane, 32wt%-36wt% of difluoromethane and 4wt%-7wt% of carbon dioxide.

[0111] And from the above test results, it can be seen that the refrigerant composition of the embodiment of the present invention has obvious temperature glide phenomenon, and can be used in conjunction with a countercurrent multi-row heat exchanger to achieve better heat exchange effect. Figure 1 As shown in the temperature-entropy diagram and the wind temperature change, during the condensation process, the temperature change of the refrigerant is not a parallel line. The condensation temperature of the refrigerant gradually decreases during the condensation process, and the wind passing through the condenser usually gradually heats up along the direction of air flow. When the refrigerant composition of the present invention is combined with a countercurrent multi-row condenser, a large temperature difference between the refrigerant temperature and the air temperature can be maintained both upstream and downstream in the air flow direction, thereby achieving a better heat exchange effect.

[0112] In some examples, the condenser can be cooled by water in addition to air cooling. For example, the condensed water on the surface of the evaporator is gathered under the condenser, and then the water is sprayed onto the heat exchange tubes of the condenser and the exhaust air flowing through the condenser through a water wheel or a water distributor, thereby reducing the air temperature. Figure 1 As shown in the figure, the air temperature will fluctuate. But in general, the air temperature will rise along the direction of air flow through the condenser.

[0113] The refrigerant composition of the present invention is suitable for scenarios with unfavorable heat dissipation conditions, has an ODP of 0, a volumetric cooling capacity superior to R22, and comparable energy efficiency.

[0114] In addition, using R1234ze(E), R152a or R1270 to replace the R134a component can also reduce the GWP value of the refrigerant composition, but will increase the flammability of the mixed refrigerant. Therefore, the present invention does not use R1234ze(E), R152a or R1270.

[0115] Heat exchange system first embodiment

[0116] This embodiment provides a heat exchange system, which is an integrated air conditioner.

[0117] The integrated air conditioner is embedded in the space between the indoor ceiling and the roof. The hot air is discharged to the outside through the exhaust duct through the exhaust holes on the wall. Due to the small diameter of the exhaust holes and the exhaust duct (no more than 120mm), the exhaust air volume is small (<500m 3 / h), when the air conditioner is placed in the kitchen, the ambient temperature inside the ceiling may be high (higher than 35°C). Therefore, in order to ensure a certain cooling output, it is necessary to use the refrigerant composition of the present invention.

[0118] like Figures 2 to 4As shown, the integrated air conditioner is provided with a main unit 100, a return air port 200 is provided near the main unit 100, and the main unit 100 is connected to an exhaust duct 300 and an air supply duct 400, and the diameter of the exhaust duct 300 is ≤120 mm.

[0119] The main unit 100 includes core components of the air conditioner, including a compressor 130 , a condenser 140 , an evaporator 110 , a throttling element 150 , an exhaust fan 170 and a supply fan 160 .

[0120] The return air vent 200 is used to draw in indoor air from below the ceiling. The return air vent 200 can be connected to the evaporator 110 via a pipe or air duct, or it can be located near the air inlet side of the evaporator 110. Indoor air is drawn in through the return air vent 200 and cooled by the evaporator 110.

[0121] The exhaust duct 300 is used to discharge hot air or exhaust gas from the room to the outside. In some embodiments, the exhaust fan 170 discharges the hot air after the heat is dissipated by the condenser 140 to the outside through the exhaust duct 300. The hot air from the condenser 140 is driven by the exhaust fan 170 and discharged through the exhaust duct 300. In some examples, part of the air that flows into the ceiling through the return air vent 200 is used to dissipate heat from the condenser 140 and is then discharged to the outside through the exhaust duct 300.

[0122] The air supply duct 400 is used to pass the processed cold air into the room. In some embodiments, the air cooled by the evaporator 110 is driven by the air supply fan 160 and transported into the room through the air supply duct 400. The air supply duct 400 is connected to the air outlet 500, and the air outlet 500 faces the room. An air guide plate may be provided at the air outlet 500, and the air guide plate can be moved, for example rotated, to control the direction and amount of air supply. In some embodiments, the end of the air supply duct 400 is connected to the air outlet 500, and the air outlet 500 is set on the wall or ceiling in the room. The air guide plate allows the user to adjust the direction and amount of air supply to achieve comfortable air distribution.

[0123] In some examples, the workflow of the integrated air conditioner may be:

[0124] Air is drawn in from the room through the return air vent 200. This air is cooled by the evaporator 110 in the main unit 100 and then delivered to the room through the air supply duct 400. Cooled air then enters the room through the air outlet 500. The condenser 140 in the main unit 100 exhausts the hot air generated during the cooling process to the outside through the exhaust duct 300.

[0125] In some examples, the integrated air conditioner performs condensation heat dissipation in high ambient temperatures. The integrated air conditioner can specifically be a kitchen refrigeration system, and the refrigeration system is composed of an evaporator 110, a gas-liquid separator 120, a compressor 130, a condenser 140, and a throttling element 150. The throttling element 150 serves as a throttling element. In particular, in order to better achieve countercurrent heat dissipation, the condenser 140 needs to be arranged in multiple rows (for example, not less than 4 rows), and the refrigerant and the air are arranged in a countercurrent form to form a step heat exchange. At this time, the temperature glide during the condensation of the mixed refrigerant can better match the refrigerant and air temperatures, reduce irreversible losses in the heat exchange process, and improve the energy efficiency of the system. The outer diameter of the condenser copper tube can be selected from 5-7mm, specifically 7mm.

[0126] The condenser can operate at an ambient temperature above 35°C.

[0127] In some examples, the integrated air conditioner is a kitchen refrigeration system, which includes an evaporator 110, a gas-liquid separator 120, a compressor 130, a condenser 140, and a throttling element 150 interconnected by a refrigerant pipe.

[0128] In kitchen refrigeration systems:

[0129] The evaporator 110 is the refrigeration part of the refrigeration system, which is used to absorb indoor heat and use it to evaporate the refrigerant. The evaporator 110 is connected to the gas-liquid separator 120 through a refrigerant pipeline.

[0130] The gas-liquid separator 120 is used to separate the refrigerant vapor and liquid refrigerant in the evaporator 110. The gaseous refrigerant in the gas-liquid separator 120 enters the compressor 130 through a pipeline, is sucked into the compressor and compressed into high-pressure gas, and the liquid refrigerant can enter the condenser 140 or the throttling element 150 or return to the evaporator 110.

[0131] Compressor 130 is the core component of the refrigeration system, responsible for compressing low-pressure refrigerant gas into high-pressure gas, increasing its temperature and pressure. The high-pressure gas discharged from compressor 130 enters condenser 140 through a pipeline. In condenser 140, the high-temperature, high-pressure gas is cooled and converted into liquid refrigerant.

[0132] Condenser 140 is used to cool high-temperature, high-pressure refrigerant gas into liquid refrigerant by dissipating heat. The liquid refrigerant in condenser 140 enters throttling element 150 through a pipeline. Throttling element 150 can be, for example, an electronic throttling element that controls the flow rate and regulates the pressure of the refrigerant.

[0133] It should be noted that the reference Figure 4As shown, the condenser can be designed into multiple rows, and water wheels can be set between adjacent rows of heat exchangers to spray water. The evaporation of water droplets can cool the air that has been heat exchanged by the previous group of condensers, increase the heat transfer temperature difference of the next group of condensers, thereby further enhancing the heat dissipation capacity of the condenser and thus improving the cooling capacity of the system.

[0134] Figure 4 The diagram illustrates a four-row condenser and refrigerant flow arrangement. The four rows are divided into two groups (2+2), with a water impeller positioned between the two groups to atomize the condensed water. The refrigerant in condenser 140 can be designed to include multiple parallel branches, each of which flows countercurrently to the air flow.

[0135] Throttling element 150 is located between condenser 140 and evaporator 110 and is used to reduce the pressure of the refrigerant. Throttling element 150 can be, for example, an electronic throttling element and can be used to adjust the operating state of the refrigeration system. After being throttled by throttling element 150, the refrigerant enters evaporator 110 through a pipeline, completing the refrigeration cycle.

[0136] Second embodiment of heat exchange system

[0137] like Figures 5 to 8 As shown, this embodiment provides a kitchen air conditioner 1000 using the refrigerant composition of the present invention. The kitchen air conditioner 1000 can be suspended and installed on a ceiling 2000 , which includes a keel 2100 as a supporting structure and a spliced ​​decorative panel 2200 installed on the keel 2100 .

[0138] The kitchen air conditioner 1000 includes a housing 1001, a first fan 1002, a second fan 1004, a first heat exchanger 1003, a second heat exchanger 1005, a compression device 1006, an electrical control box 2a, and a throttling element. The first fan 1002, the second fan 1004, the first heat exchanger 1003, the second heat exchanger 1005, the compression device 1006, and the throttling element are located within the housing 1001, forming an integrated or monolithic structure. The first fan 1002 can be used to supply air to the room, while the second fan 1004 can be used to exhaust air to the outside. The first heat exchanger 1003 functions as an evaporator during cooling, while the second heat exchanger 1005 functions as a condenser during cooling. The compression device 1006 can be a compressor.

[0139] The top of the housing 1001 is recessed downward to form a clearance groove 1014. The clearance groove 1014 can be configured as a straight strip. The clearance groove 1014 extends from one side of the housing 1001 to the other side, horizontally penetrating the housing 1001. The depth of the clearance groove 1014 can be 80% to 95% of the vertical dimension of the housing 1001. The clearance slot 1014 allows the keel 2100 to pass through. To install the kitchen air conditioner 1000, simply align the opening of the clearance slot 1014 with the keel 2100 below the ceiling 2000. Then, raise the kitchen air conditioner 1000 so that the keel 2100 enters the clearance slot 1014 until it rests at the bottom of the clearance slot 1014. Finally, secure the kitchen air conditioner 1000, for example, by attaching it to a ceiling, and installation is complete. The installed keel does not need to be removed during installation. The kitchen air conditioner 1000 is at least partially located above the ceiling 2000. The chassis of the kitchen air conditioner 1000 can be located below the ceiling 2000 and covered by a panel. After the kitchen air conditioner 1000 has been operating in cooling mode for a period of time, the temperature above the ceiling 2000 is higher than the indoor temperature below, reaching over 35°C.

[0140] A first cavity 1110 and a second cavity 1120 are provided within the housing 1001. The first cavity 1110 and the second cavity 1120 are separated by a clearance slot 1014. The housing 1001 is provided with a first air inlet 1101, a first air outlet (not shown), a second air inlet 1103, and a second air outlet 1104. The first air inlet 1101 is provided on a sidewall of the first cavity 1110. The first air inlet 1101 is connected to the indoor space, for example, via a return air vent spaced apart from the housing 1001, and is used to deliver air into the first cavity 1110. The first air outlet is provided on the bottom wall of the first cavity 1110. The first air outlet is used to output air inputted into the first cavity 1110 from the first air inlet 1101 out of the first cavity 1110. The second air inlet 1103 is provided on a sidewall of the second cavity 1120. The second air inlet 1103 is connected to the indoor space, for example, through a return air vent, and is used to deliver air into the second cavity 1120. The second air outlet 1104 is disposed on a sidewall of the second cavity 1120. The second air outlet 1104 is used to discharge air inputted from the second air inlet 1103 into the second cavity 1120. The second air outlet 1104 can be connected to the outdoors. For example, the second air outlet 1104 can discharge the air from the second cavity 1120 outdoors through an exhaust pipe that passes through an exhaust hole disposed in the wall. The diameter of the exhaust pipe is ≤120 mm.

[0141] The first fan 1002 is connected to the housing 1001. The first fan 1002 is disposed in the first cavity 1110. The first fan 1002 is configured to drive the air in the first cavity 1110 to flow from the first air inlet 1101 of the first cavity 1110 to the first air outlet of the first cavity 1110, thereby circulating the air between the indoor space and the first cavity 1110.

[0142] The first heat exchanger 1003 is disposed in the first cavity 1110. The air in the first cavity 1110 flows through the first heat exchanger 1003 when flowing from the first air inlet 1101 to the first air outlet, and the first heat exchanger 1003 can exchange heat with the air.

[0143] The second fan 1004 may be disposed in the second cavity 1120. The second fan 1004 is configured to drive the air in the second cavity 1120 to flow from the second air inlet 1103 of the second cavity 1120 to the second air outlet 1104 of the second cavity 1120, so as to draw the air from the indoor space into the second cavity 1120 and then transport the air from the second cavity 1120 to the outdoor space.

[0144] The second heat exchanger 1005 is disposed in the second cavity 1120. The second heat exchanger 1005 can be disposed near the second air inlet 1103. The air in the second cavity 1120 flows through the second heat exchanger 1005 when flowing from the second air inlet 1103 to the second air outlet 1104, and the second heat exchanger 1005 can exchange heat with the air.

[0145] The compression device 1006 can be disposed within the housing 1001. The compression device 1006 can be disposed within the first cavity 1110 or the second cavity 1120. In this embodiment, the compression device 1006 is disposed within the second cavity 1120. The compression device 1006, the second heat exchanger 1005, the throttling element, and the first heat exchanger 1003 are sequentially connected via a refrigerant pipe 1009 to form a refrigeration circuit. The refrigeration circuit can be pre-filled with the refrigerant composition of the present invention. The compression device 1006 drives the refrigerant to circulate between the first heat exchanger 1003 and the second heat exchanger 1005. A throttling element is also disposed between the first heat exchanger 1003 and the second heat exchanger 1005. In the cooling mode of the kitchen air conditioner 1000, the refrigerant evaporates when flowing through the first heat exchanger 1003, absorbing heat from the air flowing through the first cavity 1110. The refrigerant condenses when flowing through the second heat exchanger 1005, releasing heat to the air flowing through the second cavity. In this way, the temperature of the air flowing through the first cavity decreases, and the air transported from the first air outlet of the first cavity to the indoor air is cold air. Correspondingly, the temperature of the air flowing through the second cavity increases, and the air transported from the second cavity to the outdoor air is hot air.

[0146] Among them, the second heat exchanger 1005 can be a straight heat exchanger with a compact structure. The second heat exchanger 1005 includes multiple rows of first heat exchange tubes, and the number of rows of first heat exchange tubes is at least 4 rows, for example, 6 rows. The multiple rows of first heat exchange tubes are arranged in sequence along the air flow direction within the second cavity 1120 and are connected in series. For example, the ends of adjacent rows of first heat exchange tubes are connected by U-shaped tubes. The refrigerant composition of the present invention enters the second heat exchanger 1005 from the first heat exchange tube located downstream in the air flow direction and leaves the second heat exchanger 1005 from the first heat exchange tube located upstream in the air flow direction, realizing countercurrent heat exchange on the condenser side.

[0147] The first heat exchanger 1003 is constructed as a U-shaped heat exchanger, which has a large contact area with the air and a high heat exchange efficiency. The first fan 1002 is arranged in the internal cavity enclosed by the first heat exchanger 1003, and the U-shaped heat exchanger can be arranged around the first fan 1002, with a compact layout. The first heat exchanger 1003 includes at least 2 rows of U-shaped second heat exchange tubes, and at least 2 rows of second heat exchange tubes are arranged in sequence and in series along the air flow direction of the first chamber 1100. For example, the ends of the second heat exchange tubes in adjacent rows are connected by U-shaped tubes. The number of rows of second heat exchange tubes can be 2 rows, for example. The refrigerant composition of the present invention enters the first heat exchanger 1003 from the second heat exchange tube located downstream in the air flow direction, and leaves the first heat exchanger 1003 from the second heat exchange tube located upstream in the air flow direction, realizing countercurrent heat exchange on the evaporator side.

[0148] In this embodiment, the electrical control box 2a includes a control board 27a and a cooling pipe 24a. The cooling pipe 24a is used to dissipate heat from the control board 27a. The cooling pipe 24a draws refrigerant from the second heat exchanger 1005, and the refrigerant flows through the cooling pipe 24a and then returns to the second heat exchanger 1005. The cooling pipe 24a can draw refrigerant from the main flow path or the branch flow path of the second heat exchanger 1005. After passing through the cooling pipe 24a, the refrigerant flows back to the second heat exchanger 1005 before the subcooling section of the second heat exchanger 1005, and then flows to the subcooling section.

[0149] When the kitchen air conditioner 1000 is working, the control panel 27a will generate heat and transfer the heat to the cooling pipe 24a. When the kitchen air conditioner 1000 is in cooling mode, the compression device 1006 compresses the refrigerant and then outputs the high-temperature and high-pressure refrigerant to the second heat exchanger 1005. When the refrigerant flows through the second heat exchanger 1005, the heat is transferred to the air flowing through the second cavity, and the refrigerant is cooled to a low-temperature refrigerant. The refrigerant is transported from the second heat exchanger 1005 to the cooling pipe 24a. When the refrigerant flows through the cooling pipe 24a, it absorbs the heat of the control panel 27a, thereby bringing the heat emitted by the control panel 27a out of the electrical control box 2a. The refrigerant then re-enters the second heat exchanger 1005 for countercurrent heat exchange with the air, so that the cooling effect is not attenuated.

[0150] The second heat exchanger 1005 may be provided with multiple parallel pipelines, each of which exchanges heat in a countercurrent direction to the air flow. Due to objective factors (e.g., varying heat exchange efficiencies between heat exchange tubes at different locations and a heat dissipation medium such as air), it may be difficult for multiple pipelines to achieve uniform heat exchange performance. This results in different refrigerant temperatures being output from the multiple pipelines, with pipelines with better heat exchange performance outputting lower refrigerant temperatures and pipelines with poorer heat exchange performance outputting higher refrigerant temperatures. Large temperature differences in the refrigerant output from the multiple heat exchange flow paths can also lead to reduced condensing efficiency of the condenser, a decrease in cooling capacity, and increased compressor power.

[0151] In some examples, second heat exchanger 1005 includes a first pipeline 1051 and a second pipeline 1052 connected in parallel. Because first pipeline 1051 has greater contact with the cooling water sprayed by the water wheel, the heat exchange efficiency of first pipeline 1051 is higher than that of second pipeline 1052. Connecting cooling pipe 24a in series with first pipeline 1051, i.e., introducing refrigerant from first pipeline 1051 into cooling pipe 24a for electronically controlled heat dissipation before returning to first pipeline 1051 or second heat exchanger 1005, brings the temperatures of the refrigerants output from the two pipelines closer together, reducing the temperature difference between the refrigerants at the time of confluence. This can improve the condensing efficiency of second heat exchanger 1005, the cooling capacity of the air conditioner, and reduce the power of the compressor. After the refrigerant returns to the second heat exchanger 1005 through the cooling pipe 24a, the refrigerant composition therein continues to dissipate heat in a countercurrent manner with the air, or after the refrigerant returns to the second heat exchanger 1005 through the cooling pipe 24a, it merges with the second pipeline 1052 and continues to dissipate heat in a countercurrent manner with the air, resulting in a good heat dissipation effect.

[0152] In other embodiments of the present invention, the refrigerant composition of the present invention is also suitable for heat pump hot water scenarios. In this case, the condenser adopts water cooling (shell heat exchanger, plate heat exchanger, etc.), and the water and refrigerant are arranged in countercurrent, which can achieve a higher water outlet temperature.

[0153] The present invention has been described in detail above with reference to the embodiments. However, the present invention is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in the relevant technical field without departing from the spirit of the present invention.

Claims

1. A heat exchange system, characterized in that: A refrigerant composition comprising: a compressor for compressing the refrigerant composition; a condenser connected to the compressor, the condenser being provided with a plurality of parallel pipes for condensing the compressed refrigerant composition; a throttling element connected to the condenser and configured to reduce the pressure of the condensed refrigerant composition; an evaporator, one end of which is connected to the throttling element and the other end of which is connected to the compressor, for evaporating a low-pressure refrigerant composition; a first heat exchange device, wherein the first heat exchange device cools the condenser using a first medium, the condenser comprising a plurality of rows of first heat exchange tubes arranged and sequentially connected along a flow direction of the first medium, the refrigerant composition entering the condenser from the first heat exchange tubes located downstream in the flow direction of the first medium and flowing out of the condenser from the first heat exchange tubes located upstream in the flow direction of the first medium; The refrigerant composition comprises, based on the total mass of the refrigerant composition, 58 wt% to 62 wt% of 1,1,1,2-tetrafluoroethane, 32 wt% to 36 wt% of difluoromethane, and 4 wt% to 7 wt% of carbon dioxide, wherein the refrigerant composition is a non-azeotropic composition; Under the operating condition of a condensing temperature of 65°C, the temperature glide of the refrigerant composition is 6.5 to 10.5°C.

2. The heat exchange system according to claim 1, characterized in that: The first heat exchange tubes are in at least three rows.

3. The heat exchange system according to claim 2, characterized in that: The number of the first heat exchange tubes is 4 to 10.

4. The heat exchange system according to claim 1, characterized in that: The first medium includes air, and the air volume generated by the air flow is less than 500m 3 / h.

5. The heat exchange system according to claim 4, characterized in that: The first heat exchange device further includes an exhaust pipe, which is used to exhaust the air, and the diameter of the exhaust pipe is ≤120 mm.

6. The heat exchange system according to claim 5, characterized in that: The diameter of the exhaust pipe is ≥50mm.

7. The heat exchange system according to claim 1, characterized in that: The heat exchange system also includes a second heat exchange device, which uses a second medium to exchange heat with the evaporator. The evaporator includes multiple rows of second heat exchange tubes arranged and connected in sequence along the flow direction of the second medium. The refrigerant composition enters the evaporator from the second heat exchange tubes located downstream in the flow direction of the second medium and flows out of the evaporator from the second heat exchange tubes located upstream in the flow direction of the second medium.

8. The heat exchange system according to claim 7, characterized in that: The number of the second heat exchange tubes is 2 to 10.

9. The heat exchange system according to claim 1, characterized in that: The condenser is suitable for working under the condition that the ambient temperature is higher than 35°C.

10. The heat exchange system according to any one of claims 1 to 9, characterized in that: Under the operating conditions of an evaporation temperature of 13° C. and a condensation temperature of 65° C., the exhaust temperature of the refrigerant composition is less than 107.5° C. and the condensation pressure is less than 3.7 MPa.

11. The heat exchange system according to claim 1, characterized in that: The safety level of the refrigerant composition reaches A1; under the operating conditions of an evaporating temperature of 13°C and a condensing temperature of 65°C, the exhaust temperature is less than 105°C, the condensing pressure is less than 3.6 MPa, the relative volumetric cooling capacity is above 115%, and the temperature glide under the condensing pressure is greater than 7°C.

12. The heat exchange system according to any one of claims 1 to 9, characterized in that: The condenser is a straight heat exchanger.

13. The heat exchange system according to any one of claims 1 to 9, characterized in that: Each pipeline flows through each row of first heat exchange tubes; for each pipeline, the refrigerant composition enters the pipeline from the first heat exchange tube located downstream in the flow direction of the first medium, and flows out of the pipeline from the first heat exchange tube located upstream in the flow direction of the first medium.

14. The heat exchange system according to claim 13, characterized in that: The heat exchange system further includes an electronic control box, which includes a control panel and a cooling pipe for dissipating heat from the control panel; one of the multiple pipelines is connected in series with the electronically controlled cooling pipe, and the refrigerant composition returns to the condenser after passing through the cooling pipe and is cooled by the first medium.

15. The heat exchange system according to any one of claims 1 to 9, characterized in that: The evaporator is a U-shaped evaporator, comprising at least two rows of U-shaped second heat exchange tubes, wherein the multiple rows of second heat exchange tubes are sequentially arranged along the air flow direction and sequentially connected in series.

16. The heat exchange system according to any one of claims 1 to 9, characterized in that: The heat exchange system is an integrated air conditioner, which includes a shell. The compressor, the condenser, the throttling element and the evaporator are located in the shell and are interconnected by a refrigerant pipe.

17. The heat exchange system according to claim 16, characterized in that: The integrated air conditioner is located indoors, and the condenser is connected to the outdoors through an exhaust pipe.

18. The heat exchange system according to claim 16, characterized in that: The integrated air conditioner is installed in a suspended ceiling, and the shell has a recessed groove for matching with the keel of the ceiling so that the shell is at least partially located above the ceiling.

19. The heat exchange system according to claim 16, characterized in that: The integrated air conditioner is a kitchen air conditioner, a bathroom air conditioner or a mobile air conditioner.

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