Heat exchange system

Abstract

The invention provides a heat exchange system which comprises a refrigerant composition, a compressor, a condenser, a throttling element, an evaporator and a first heat exchange device, and the refrigerant composition comprises 52 wt%-62 wt% of 1, 1, 1, 2-tetrafluoroethane, 32 wt%-40 wt% of difluoromethane and 4 wt%-8 wt% of carbon dioxide according to the total mass of the refrigerant composition. The refrigerant composition is a non-azeotropic composition; and under the working condition that the condensation temperature is 65 DEG C, the temperature slip of the refrigerant composition is 6.5-10.5 DEG C. According to the heat exchange system, due to the fact that the non-azeotropic refrigerant composition is used, the heat exchange system has the temperature slippage characteristic. The refrigerant can be gradually evaporated and condensed at different temperatures in the evaporator and the condenser through temperature slippage, and the temperature slippage is better matched with the temperature gradient of the heat exchanger, so that the heat exchange efficiency is improved.

Description

Technical Field

[0001] The 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, playing 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 traditional heat exchange systems, the compressor, condenser, throttling element and evaporator are four key components. The compressor is responsible for compressing the refrigerant to increase its temperature and pressure; the condenser is used to condense high-temperature and high-pressure refrigerant; the throttling element reduces the pressure of the refrigerant to make it enter a low-temperature and low-pressure state; the evaporator evaporates the low-temperature and low-pressure refrigerant and absorbs heat from the environment. The collaborative 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 properties 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 realized.

[0004] Traditional heat exchange systems usually rely on a single refrigerant, but these refrigerants have many problems, such as the destruction of the ozone layer. In addition, the thermodynamic performance and efficiency of a single refrigerant often cannot meet the needs of modern industry and life. Therefore, how to combine refrigerants to develop an efficient and environmentally friendly heat exchange system is an urgent problem to be solved. Summary of the invention

[0005] The present invention aims to solve at least one of the above-mentioned technical problems existing in the prior art. To this end, the present invention provides a heat exchange system, which contains a plurality of refrigerant compositions in a specific ratio to form a non-azeotropic mixture. The heat exchange system of this design is suitable for scenes with small air volume heat dissipation or high ambient temperature. The refrigerant composition can replace R22, has better energy efficiency than R32, and has an ODP (Ozone Depletion Potential) of 0.

[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 used to condense the compressed refrigerant composition;

[0009] a throttling element connected to the condenser and used 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 enters the condenser from the first heat exchange tubes located downstream in the flow direction of the first medium, and flows out of the condenser from the first heat exchange tubes located upstream in the flow direction of the first medium;

[0012] The refrigerant composition, based on the total mass of 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; 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] It can be understood that the heat exchange system of the present invention has a temperature glide characteristic due to the use of a non-azeotropic refrigerant composition. The 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, thereby improving the heat exchange efficiency.

[0015] Furthermore, since the refrigerant composition can more effectively utilize the temperature glide characteristics during the evaporation and condensation process, when used in conjunction with a countercurrent heat exchanger, the irreversible loss during the heat exchange process can be reduced, 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 high ambient temperature conditions. 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 the condensation effect. Furthermore, the condenser design with multiple rows of first heat exchange tubes can provide a larger heat exchange area in a smaller volume, which helps to reduce the overall volume and weight of the system. This has important advantages for application scenarios 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).

[0018] Specifically: The safety level of the refrigerant composition is A1 or A2L, which means that 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 a non-azeotropic composition, which means that its components can boil or condense separately under certain conditions without forming a fixed boiling point. This characteristic allows the refrigerant to produce temperature glide in the evaporator or condenser, helping to reduce irreversible losses in the heat exchange process.

[0020] The temperature glide characteristics of the refrigerant composition can be combined with a multi-row counter-flow heat exchanger 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 condensation temperature, which is above 52° C., for example, above 65° C. When the heat dissipation air volume of the condenser is small, due to the large temperature difference between the condenser and the ambient temperature, the small air volume can also achieve a good heat dissipation effect of the condenser and improve the refrigeration capacity; when used in a high temperature environment, the condenser and the ambient temperature still maintain a certain temperature difference, and high temperature refrigeration can be achieved.

[0022] The refrigerant composition of the present invention has a lower flammability than R32 (i.e., difluoromethane) because both R134a (i.e., 1,1,1,2-tetrafluoroethane) and R744 (i.e., CO2) are non-flammable.

[0023] Taking the above advantages into consideration, the refrigerant composition of the present invention can improve the energy efficiency of the system when used in scenarios with low air volume heat dissipation and high ambient temperature. By reducing energy loss, the system can achieve refrigeration more effectively, reduce energy consumption and reduce operating costs. The refrigerant composition of the present invention also has the advantages 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 tube can significantly increase the heat transfer area of ​​the condenser. More rows of heat exchange tubes provide a larger contact area, making the heat exchange between the refrigerant and the first medium more complete, and improving the overall heat exchange efficiency. More rows of heat exchange tubes can achieve temperature glide on a longer heat exchange path, thereby better matching the temperature gradient of the cooling medium. This can optimize the phase change process of the refrigerant and reduce 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 condensation temperature range, especially under high ambient temperature conditions (above 35°C). The design of more rows of heat exchange tubes enables the condenser to maintain a good condensation effect under high temperature conditions, ensuring the cooling capacity and stability of the system. 3 / h), more rows of heat exchange tubes can ensure the heat dissipation effect of the condenser through a larger heat exchange area and more effective countercurrent heat exchange. This allows the system to operate efficiently under low air volume conditions and adapt to more practical application scenarios. The design of multiple rows of countercurrent heat exchange tubes effectively reduces the irreversible loss in the heat exchange process by gradually cooling the refrigerant in stages. More rows of heat exchange tubes enable the condenser to exchange heat more stably when facing different working conditions, reducing the mechanical and thermal stress caused by temperature fluctuations. This enhances the reliability of the system and reduces the failure rate 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, and can provide efficient refrigeration solutions from small air volume heat dissipation to high temperature environment applications. This makes the system have a wider market adaptability and application prospects.

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

[0028] Lower air flow means that the heat exchange system requires less fan power during operation, thereby reducing energy consumption. This helps reduce the overall energy consumption of the system and saves operating costs. Small air flow produces less noise, which can significantly reduce the operating noise of the system. This is an important advantage for application scenarios that require a quiet environment, such as home air conditioning, office spaces, and hospitals, and improves the user experience. Smaller air volumes reduce the load and wear of the fan, extend the service life of the fan and other related components, reduce equipment maintenance and replacement costs, and improve the long-term reliability and economy of the system.

[0029] In addition, the small air volume design enables the heat exchange system to operate efficiently in environments with limited space or poor ventilation conditions. For example, in a high temperature environment (above 35°C), the system can still achieve effective heat exchange with a lower air volume to ensure the cooling effect. This makes the system more adaptable in more practical application scenarios. Although the air volume is small, by increasing the number of rows of the first heat exchange tube (preferably 4 to 10 rows), the heat transfer area of ​​the condenser is expanded, and the small air volume air can be fully utilized for effective heat exchange. The counterflow design and temperature glide characteristics further optimize the condensation process, improve the heat exchange efficiency and system performance. Using a small air volume as a cooling medium reduces the impact on the environment, which is in line with the concept of environmental protection and sustainable development. At the same time, the efficient operation and low energy consumption characteristics of the system also help to reduce carbon emissions and protect the environment. Smaller air flow requirements mean that smaller fans and ventilation equipment can be used, reducing the initial equipment procurement and installation costs. This is particularly beneficial for small refrigeration systems or application scenarios with limited budgets.

[0030] According to some embodiments of the present invention, the first heat exchange device further comprises an exhaust pipe, wherein the exhaust pipe is used to exhaust 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. For installation environments with limited space, such as small machine rooms, household air conditioning units, etc., it can be arranged and installed more flexibly, saving precious space resources.

[0032] According to some embodiments of the present invention, the heat exchange system also includes a second heat exchange device, which uses a second medium to exchange heat with the evaporator, and the evaporator includes a plurality of rows of second heat exchange tubes arranged along the flow direction of the second medium and connected in sequence, and 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 using multiple rows of second heat exchange tubes and adopting a countercurrent heat exchange design, the heat of the second medium can be transferred to the refrigerant composition more efficiently. This can maximize the temperature difference between the two, improve the heat exchange efficiency, and thus improve the refrigeration capacity and performance of the entire system. The temperature glide characteristics generated by the non-azeotropic refrigerant composition during the evaporation process, combined with the countercurrent heat exchange design, make the heat exchange process more sufficient. The temperature glide can better match the temperature gradient of the second medium, reduce the irreversible loss during the heat exchange process, and further improve the energy efficiency of the system. Furthermore, the multi-row heat exchange tube design increases the heat transfer area of ​​the evaporator, so that the refrigerant has enough time and area in the evaporator to complete the heat exchange process. This not only improves the evaporation efficiency of the refrigerant, but also ensures that the evaporator can provide a stable cooling effect under various working conditions. The design of multiple rows of heat exchange tubes helps to evenly distribute the heat load and reduce the load and stress of a single heat exchange tube. This can reduce equipment damage caused by overheating or local overcooling, and improve the overall reliability and service life of the system. The design of the heat exchange system of the present invention can adapt to different types of second media, such as water, air or other liquid cooling media, so that the system has a wider range of applications. Whether in industrial cooling, air conditioning systems or special environments, it can operate efficiently and meet diverse refrigeration needs. By optimizing the heat exchange process and reducing irreversible losses, the system can achieve efficient refrigeration at lower energy consumption. This not only reduces energy consumption and operating costs, but also meets the current requirements of energy conservation and environmental protection, and helps reduce carbon emissions and environmental impact. As a result, the design of multiple rows of heat exchange tubes can better control the flow path and heat exchange process of the refrigerant, ensuring that the system can operate stably under different loads and working conditions. This can improve the control accuracy and response speed of the system and meet the dynamic needs of different 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 the second heat exchange tube can significantly increase the heat transfer area of ​​the evaporator, thereby improving the efficiency of heat exchange. The design of heat exchange tube rows of at least 2 to 10 makes the system more flexible and adjustable. The number of heat exchange tubes can be flexibly adjusted according to actual needs and application scenarios to meet user needs to the greatest extent.

[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 the refrigeration system are particularly important. By designing the condenser to work in high temperature environments, the performance of the system can be improved, and the user experience and satisfaction can be enhanced.

[0038] According to some embodiments of the present invention, the mass percentage of 1,1,1,2-tetrafluoroethane can be, for example, 52wt%, 52.5wt%, 53wt%, 53.5wt%, 54wt%, 54.5wt%, 55wt%, 55.5wt%, 56wt%, 56.5wt%, 57wt%, 57.5wt%, 58wt%, 58.5wt%, 59wt%, 59.5wt%, 60wt%, 60.5wt%, 61wt%, 61.5wt%, 62wt%, any one of the values ​​or a range 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%, 40wt%, any one of the values ​​or a range 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 selected from the group consisting of 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 safety level of the refrigerant reach A1, further reduce the exhaust temperature and condensing pressure, and increase the relative volumetric 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 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.

[0044] The condensing temperature of the refrigerant composition refers to the average value of the dew point temperature and the bubble point temperature under the corresponding pressure (condensing pressure); the evaporation temperature of the refrigerant composition refers to the average value of the dew point temperature and the bubble point temperature under the corresponding pressure (evaporation pressure).

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

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

[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 3.6MPa, the relative volumetric refrigeration capacity is above 115%, and the temperature glide is greater than 7°C.

[0048] The safety level reaches A1, which means that the refrigerant has low toxicity and non-flammability, and has low safety risks to humans and the environment. It is suitable for safe use in various scenarios, reducing safety hazards and usage restrictions. The exhaust temperature is less than 105°C. The lower exhaust temperature reduces the heat load of the compressor and other components, reduces the risk of equipment failure due to overheating, and thus improves the stability and reliability of the system. The condensing pressure is less than 3.6MPa. The lower condensing pressure reduces the mechanical and thermal stresses on the system, extends the life of the equipment, and reduces the frequency and cost of maintenance and replacement. The relative volumetric cooling capacity is above 115%. The higher relative volumetric cooling capacity indicates that it can provide higher cooling capacity under the same volume, improves the energy efficiency ratio (COP) of the system, reduces energy consumption, and reduces operating costs. The temperature glide is greater than 7°C. The temperature glide characteristic enables the refrigerant to better match the temperature gradient of the heat exchanger during evaporation and condensation, optimizes the heat transfer process, and further improves the heat exchange efficiency and overall system performance. Therefore, due to the high safety level and good performance parameters of the refrigerant, it is suitable for various commercial, industrial and household application scenarios, especially under high temperature and high load conditions.

[0049] According to some embodiments of the present invention, the condenser is a straight heat exchanger, and the condenser 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 the heat exchange efficiency, allowing the refrigerant to dissipate heat faster during the condensation process, thereby improving the refrigeration performance of the system.

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

[0052] Multiple rows of heat exchange tubes are arranged in sequence along the air flow direction and connected in series, so that heat can be transferred gradually and the heat exchange process is more uniform and stable. This helps to avoid heat competition between heat exchange tubes, reduce local overheating or overcooling, and optimize the heat exchange process. The design of multiple rows of heat exchange tubes also makes the heat more evenly distributed in the condenser, reduces the load and stress of the heat exchange tubes, and reduces the risk of equipment damage caused by overheating or local overcooling. This helps to improve the stability and reliability of the system and extend the service life of the equipment.

[0053] The straight heat exchanger design is suitable for working conditions in high temperature environments and can better adapt to the requirements of high ambient temperatures. This allows the system to maintain a stable heat dissipation effect in high temperature environments, improving the reliability and adaptability of the system. It can be understood that the straight heat exchanger has a compact structure and occupies less space, which is suitable for installation environments with limited space. This helps to simplify the layout and installation of the system, 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 share the flow of refrigerant, and each pipe flows through all heat exchange tube rows, ensuring uniform flow of refrigerant in the condenser, avoiding local overcooling or overheating, and achieving a more uniform temperature distribution. Furthermore, the parallel multi-pipe design effectively reduces the flow resistance in a single pipe, reduces the pressure drop of the system, thereby reducing the workload of the compressor and improving the energy efficiency ratio (COP) of the entire system. Furthermore, even if a pipe is blocked or has other problems, the multi-pipe parallel design will not completely affect the operation of the entire condenser, and the system can continue to operate with higher reliability and stability. In addition, the countercurrent heat exchange method can better utilize the temperature gradient and improve the heat transfer efficiency. This is especially important for application scenarios that require precise temperature control, such as industrial cooling processes. Furthermore, the multi-pipe parallel design enables the condenser to adapt to different operating conditions and load changes, ensuring efficient operation under various operating conditions. Whether it is partial load or full load operation, the condenser can maintain good performance. Due to the improvement of heat exchange efficiency and the reduction of pressure drop, the overall energy consumption of the system is reduced, and the operating cost is significantly reduced. 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 comprises an electrical control box, which comprises a control panel and a cooling pipe for dissipating heat from the control panel; one of the plurality of pipelines is connected in series with a cooling pipe for dissipating heat from the electrical control panel, and the refrigerant composition returns to the condenser after passing through the cooling pipe and is cooled by the first medium.

[0057] The cooling pipe is used to dissipate heat from the control panel of the electric control box, ensuring that the control panel maintains a suitable temperature during operation, avoiding control system failures caused by overheating, and improving the reliability and stability of the control system. The heat dissipation of the electric control box is connected in series with the condenser of the refrigeration system, reducing the need for an independent heat dissipation system, realizing the integrated design of system functions, simplifying the system structure, and reducing the equipment volume and installation space. After the refrigerant dissipates heat for the electric control box in the cooling pipe, it returns to the condenser with part of the heat and is cooled by the first medium (such as air), effectively utilizing the waste heat of the refrigerant and improving the energy efficiency of the overall system. Through the dual heat dissipation paths of the cooling pipe and the condenser, the heat of the refrigerant is more fully released, reducing the load of the compressor, improving the energy efficiency ratio (COP) of the system, and thus reducing energy consumption and operating costs. Keeping the control panel in a low-temperature working environment reduces the damage to electronic components caused by high temperature, prolongs the service life of the control panel and the entire electric control system, and reduces the frequency and cost of maintenance and replacement. Using the refrigerant to dissipate heat from the electric control box avoids the problem of local overheating of the electric control box, ensuring that the system can operate stably under high load or high temperature environments, and enhancing the overall reliability of the system.

[0058] According to some embodiments of the present invention, the evaporator is a U-shaped evaporator, including at least 2 rows of U-shaped second heat exchange tubes, and multiple rows of first heat exchange tubes are arranged in sequence along the air flow direction and connected in series in sequence.

[0059] At least two rows of U-shaped second heat exchange tubes are used in the evaporator, which effectively increases the heat exchange area, allowing more heat to be transferred to the refrigerant. This helps to improve the heat exchange efficiency, allowing the evaporator to more fully absorb the heat in 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 keel of the ceiling 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 in one housing simplifies the installation process of the air conditioning system. Users only need to install one overall device instead of installing and connecting multiple components separately, saving installation time and labor costs. In addition, the one-piece design also simplifies the maintenance of the system because users only need to deal with one overall device instead of multiple individual components. The one-piece design integrates all components in one housing, reducing the installation space required for the system. This is especially beneficial for environments with limited space, such as small rooms or vehicle interiors. In addition, the use of pipes and connectors is reduced, further saving space. Furthermore, since all major components are integrated in one housing and interconnected by refrigerant pipes, the number of connection points in the refrigerant pipe system is reduced, thereby reducing the risk of refrigerant leakage. This helps to improve the stability and reliability of the system. In addition, the one-piece design helps to reduce the length of pipes and connection points, reduce the pressure loss and flow resistance of the refrigerant in the pipes, and thus improve the overall efficiency of the system. In addition, the integrated design can also optimize the heat exchange between components, further improving the energy efficiency of the system. The one-piece design also makes the appearance of the air conditioning system more neat and beautiful, without the need for additional pipes and connectors, reducing the messy appearance. 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 via an exhaust duct.

[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] Since the all-in-one air conditioner is partially or completely installed above the indoor ceiling, it effectively saves the available indoor space. This is especially beneficial for indoor environments with limited space, such as commercial places, offices or residences. Through ceiling installation, the components of the all-in-one air conditioner can be completely hidden above the ceiling, making the indoor space more neat and beautiful. This helps to improve the quality and comfort of indoor decoration and create a more comfortable indoor environment. Installing the main components of the air conditioner above the ceiling can effectively reduce the noise interference generated when the air conditioner is running. This has a significant improvement effect on places that require 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, which is convenient for maintenance and cleaning. Maintenance personnel can more easily approach and operate the air conditioning equipment, reducing the difficulty of maintenance and maintenance, and extending the service life of the equipment. Since the all-in-one air conditioner is partially or completely installed above the indoor ceiling, it can more effectively blow cold air evenly to every corner of the room, improving the cooling or heating effect of the air conditioner. This helps to ensure the comfort and temperature balance of the indoor air. Ceiling installation can also effectively protect the air conditioning equipment from collision or damage from external objects, improving the safety and reliability of the air conditioning equipment. This helps reduce accidental damage and repair costs, and ensures 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 It is a schematic diagram of a refrigerant circulation system of a first embodiment of a heat exchange system of the present invention.

[0070] Figure 4 It is a flow diagram of a 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 in a second embodiment of the heat exchange system of the present invention when viewed from a certain top view after the shell is 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 8It is a flow diagram of a condenser of 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: air 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: a clearance groove; 1051: a first pipeline; 1052: a 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 be combined with the embodiments to clearly and completely describe the concept of the present invention and the technical effects produced, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments 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, the description with reference to the terms "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 schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[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 conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[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 a refrigerant composition, which is a mixture 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: evaporation temperature 13°C, condensation temperature 65°C (for mixed refrigerants, the evaporation temperature and condensation temperature are defined by the average value of the dew point and bubble point under a certain pressure), superheat 2°C, subcooling 10°C, and compressor isentropic efficiency 0.7.

[0097] The refrigerant properties are obtained by calling REFPROP software. Compare the volumetric cooling capacity, refrigeration energy efficiency EER, condensing pressure, pressure ratio, temperature glide (under condensing pressure), exhaust temperature parameters. The relative values ​​in the calculation results are based on R22 as a reference.

[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 composition of the present invention, the relative volumetric refrigeration capacity of all embodiments exceeds R22 and is more than 115% of R22, and the relative energy efficiency is only slightly lower than R22, but the difference is within 4%. The condensing pressure is lower than R32 and slightly higher than R22, and the pressure ratio is basically the same as 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 refrigeration 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, and the changes in various indicators are smaller than when CO2 replaces R134a.

[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 indicate that changes in the amounts of different components in the refrigerant composition of the present invention will have varying degrees of influence on the relative volumetric refrigeration 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 3.6MPa, the relative volumetric refrigeration capacity is above 115%, and the temperature glide is greater than 7°C, so as to better meet the reliability requirements of the system and the heat exchange requirements of a small exhaust volume and a 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] It can be seen from the above test results that the refrigerant composition of the embodiment of the present invention has an obvious temperature glide phenomenon, and can be used in conjunction with a countercurrent multi-row heat exchanger to achieve a 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. During the condensation process, the condensation temperature of the refrigerant gradually decreases, 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 can be gathered under the condenser, and then the water can be 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, resulting in a decrease in the air temperature. Figure 1 As shown in the figure, the air temperature will change in a tortuous way. But in general, along the flow direction of the air through the condenser, the air temperature shows an overall upward trend.

[0113] The refrigerant composition of the present invention is suitable for scenes with unfavorable heat dissipation conditions, with ODP=0, a volumetric refrigeration capacity better than R22, and a comparable energy efficiency.

[0114] In addition, using R1234ze(E) or 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) or 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 in the ceiling may be high (higher than 35°C). Therefore, in order to ensure a certain cooling capacity output, the refrigerant composition of the present invention needs to be used.

[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 with an exhaust duct 300 and an air supply duct 400, and the diameter of the exhaust duct 300 is ≤120 mm.

[0119] The host 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 an air supply fan 160 .

[0120] The return air vent 200 is used to introduce indoor air from below the ceiling. The return air vent 200 may be connected to the evaporator 110 through a pipe or an air duct, and the return air vent 200 may also be arranged near the air inlet side of the evaporator 110. Indoor air is sucked in through the return air vent 200 and cooled by the evaporator 110.

[0121] The exhaust duct 300 is used to discharge indoor hot air or exhaust gas 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 of the condenser 140 is driven by the exhaust fan 170 and discharged through the exhaust duct 300. In some examples, part of the air flowing into the ceiling through the return air port 200 is used for heat dissipation of the condenser 140 and is discharged to the outside through the exhaust duct 300.

[0122] The air supply duct 400 is used to pass the treated 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 to 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, such as 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] The return air vent 200 draws in air from the room, and the drawn in air is cooled by the evaporator 110 in the main unit 100, and the cooled air is delivered to the room through the air supply pipe 400. The cold air enters the room through the air outlet 500. The condenser 140 in the main unit 100 discharges the hot air generated during the cooling process to the outside through the exhaust pipe 300.

[0125] In some examples, the integrated air conditioner performs condensation heat dissipation in a high ambient temperature. The integrated air conditioner can be specifically 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 stepped heat exchange. At this time, the temperature glide during the condensation of the mixed refrigerant can make the refrigerant and the air temperature better match, reduce the irreversible loss of 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 system:

[0129] The evaporator 110 is a refrigeration part of the refrigeration system, which is used to absorb indoor heat and use it for refrigerant evaporation. 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 in by 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] The compressor 130 is the core component of the refrigeration system, which is responsible for compressing the low-pressure refrigerant gas into high-pressure gas, increasing its temperature and pressure. The high-pressure gas discharged from the compressor 130 enters the condenser 140 through a pipeline, and the high-temperature and high-pressure gas in the condenser 140 is cooled into liquid refrigerant.

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

[0133] It should be noted that the reference Figure 4As shown, the condenser can be designed to be divided 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 refrigeration capacity of the system.

[0134] Figure 4 The diagram shows a 4-row condenser and refrigerant flow arrangement, where the 4-row condenser is divided into 2 groups (2+2), and a water wheel is provided between the two groups to atomize the condensed water. The refrigerant in the condenser 140 can be designed to include multiple parallel branches, each branch being countercurrent to the air flow direction.

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

[0136] Heat exchange system second embodiment

[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, and the ceiling 2000 includes a keel 2100 as a supporting structure and a spliced ​​decorative plate 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 electric 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 in the housing 1001 to form an integral or one-piece structure. The first fan 1002 can be used to supply air to the room, the second fan 1004 can be used to exhaust air to the outside, the first heat exchanger 1003 is used as an evaporator in cooling, the second heat exchanger 1005 is used as a condenser in cooling, and 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 set as a straight groove. The clearance groove 1014 extends from one side of the housing 1001 to the other side of the housing 1001, and the clearance groove 1014 passes through the housing 1001 in the horizontal direction. The depth of the clearance groove 1014 can be 80% to 95% of the size of the housing 1001 in the vertical direction. The clearance groove 1014 can be used for the keel 2100 to pass through. When installing the kitchen air conditioner 1000, it is only necessary to align the opening of the clearance groove 1014 with the keel 2100 below the ceiling 2000, and then raise the height of the kitchen air conditioner 1000 so that the keel 2100 enters the clearance groove 1014 until the keel 2100 is located at the bottom of the clearance groove 1014. Finally, the kitchen air conditioner 1000 is fixed, for example, by fixing the kitchen air conditioner 1000 through a ceiling to complete the installation. During the installation of the kitchen air conditioner 1000, it is not necessary to remove the installed keel. The kitchen air conditioner 1000 is at least partially located above the ceiling 2000, and the chassis of the kitchen air conditioner 1000 can be located below the ceiling 2000 and covered with a panel. After the kitchen air conditioner 1000 has been in cooling operation for a certain period of time, the temperature above the ceiling 2000 is higher than the temperature of the indoor space below the ceiling 2000, and can reach more than 35°C.

[0140] The housing 1001 is provided with a first cavity 1110 and a second cavity 1120. 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 in the figure), a second air inlet 1103 and a second air outlet 1104. The first air inlet 1101 is provided on the side wall of the first cavity 1110. The first air inlet 1101 is connected to the indoor space, for example, through a return air outlet spaced apart from the housing 1001, and is used to transport 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 the air input into the first cavity 1110 from the first air inlet 1101 to the first cavity 1110. The second air inlet 1103 is provided on the side wall of the second cavity 1120. The second air inlet 1103 is connected to the indoor space, for example, through the return air outlet, and is used to transport air into the second cavity 1120. The second air outlet 1104 is provided on the side wall of the second cavity 1120. The second air outlet 1104 is used to output the air input into the second cavity 1120 from the second air inlet 1103. The second air outlet 1104 can be connected to the outdoor space, for example, the second air outlet 1104 can discharge the second cavity 1120 to the outside through the exhaust pipe through the exhaust hole provided on the wall, and the diameter of the exhaust pipe is ≤120mm.

[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, so as to realize air circulation 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 inhale the air in 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 may be disposed close to 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 may be arranged in the housing 1001. The compression device 1006 may be arranged in the first cavity 1110 or in the second cavity 1120. In this embodiment, the compression device 1006 is arranged in the second cavity 1120. The compression device 1006, the second heat exchanger 1005, the throttling element and the first heat exchanger 1003 are connected in sequence through the refrigerant pipe 1009 to form a refrigeration circuit. The refrigerant composition of the present invention may be pre-filled in the refrigeration circuit. The compression device 1006 can drive the refrigerant to circulate between the first heat exchanger 1003 and the second heat exchanger 1005. A throttling element is also arranged 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 and absorbs the heat of the air flowing through the first cavity 1110. The refrigerant releases heat to the air flowing through the second cavity and condenses when flowing through the second heat exchanger 1005. 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 room 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 room 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. Multiple rows of first heat exchange tubes are arranged in sequence along the air flow direction in the second cavity 1120 and connected in series in sequence, 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 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 connected 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 the 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 electric control box 2a includes a control board 27a and a cooling pipe 24a. The cooling pipe 24a is used for heat dissipation of the control board 27a. The cooling pipe 24a introduces refrigerant from the second heat exchanger 1005, and the refrigerant flows back to the second heat exchanger 1005 after passing through the cooling pipe 24a. The cooling pipe 24a can introduce 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 board 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, it transfers the heat to the air flowing through the second cavity. 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 board 27a, thereby bringing the heat emitted by the control board 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 a plurality of parallel pipelines, each of which exchanges heat in a countercurrent direction with the air flow direction. Due to some objective reasons (such as different heat exchange efficiencies between heat exchange tubes at different positions and heat dissipation media such as air, etc.), it is difficult to achieve the same heat exchange effect between the plurality of pipelines, resulting in different temperatures of the refrigerants output by the plurality of pipelines. The temperature of the refrigerant output by the pipeline with better heat exchange effect is lower, and the temperature of the refrigerant output by the pipeline with poor heat exchange effect is higher. If the temperature difference of the refrigerants output by the plurality of heat exchange flow paths is large, the condensation effect of the condenser will also be reduced, the cooling capacity will be reduced, and the power of the compressor will be increased.

[0151] In some examples, the second heat exchanger 1005 includes a first pipeline 1051 and a second pipeline 1052 connected in parallel. Since the first pipeline 1051 is in contact with more cooling water sprinkled by the water wheel, the heat exchange efficiency of the first pipeline 1051 is higher than that of the second pipeline 1052. The cooling pipe 24a is connected in series to the first pipeline 1051, that is, the refrigerant of the first pipeline 1051 is introduced into the cooling pipe 24a for electronically controlled heat dissipation, and then returned to the first pipeline 1051 or the second heat exchanger 1005, so that the temperature of the refrigerant output from the two pipelines is closer, so that the temperature difference of the refrigerant when it converges is reduced, which can improve the condensation efficiency of the second heat exchanger 1005 and 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 countercurrent 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 countercurrent 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 in conjunction with the embodiments, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose 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 and used to condense the compressed refrigerant composition; a throttling element connected to the condenser and used 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 enters the condenser from the first heat exchange tubes located downstream in the flow direction of the first medium, and flows out of the condenser from the first heat exchange tubes located upstream in the flow direction of the first medium; The refrigerant composition, based on the total mass of 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; 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 at least 3 rows, preferably 4 to 10 rows.

3. 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.

4. The heat exchange system according to claim 3, characterized in that: The first heat exchange device further includes an exhaust pipe, and the exhaust pipe is used to exhaust the air. The diameter of the exhaust pipe is ≤120 mm, and preferably the diameter of the exhaust pipe is ≥50 mm and ≤120 mm.

5. 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 a plurality of rows of second heat exchange tubes arranged along the flow direction of the second medium and connected in sequence. 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.

6. The heat exchange system according to claim 5, characterized in that: The number of the second heat exchange tubes is 2 to 10.

7. 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.

8. The heat exchange system according to any one of claims 1 to 7, 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.

9. The heat exchange system according to any one of claims 1 to 7, characterized in that: The refrigerant composition comprises: 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.

10. The heat exchange system according to claim 9, characterized in that: The safety level of the refrigerant composition reaches A1; under the operating conditions of an evaporation temperature of 13°C and a condensation temperature of 65°C, the exhaust temperature is less than 105°C, the condensation pressure is less than 3.6MPa, the relative volumetric refrigeration capacity is above 115%, and the temperature glide under the condensation pressure is greater than 7°C.

11. The heat exchange system according to any one of claims 1 to 7, characterized in that: The condenser is a straight heat exchanger, and the number of rows of first heat exchange tubes is at least 4.

12. The heat exchange system according to any one of claims 1 to 7, characterized in that: 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.

13. The heat exchange system according to claim 12, characterized in that: The heat exchange system also includes an electric control box, which includes a control panel and a cooling pipe for heat dissipation of the control panel; one of the multiple pipelines is connected in series with a cooling pipe for electric control heat dissipation, and the refrigerant composition returns to the condenser after passing through the cooling pipe and is cooled by the first medium.

14. The heat exchange system according to any one of claims 1 to 7, characterized in that: The evaporator is a U-shaped evaporator, including at least 2 rows of U-shaped second heat exchange tubes, and the multiple rows of second heat exchange tubes are arranged in sequence along the air flow direction and connected in series in sequence; the second heat exchange tubes are preferably 2 to 10 rows.

15. The heat exchange system according to any one of claims 1 to 7, characterized in that: 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 pipeline.

16. The heat exchange system according to claim 15, characterized in that: The integrated air conditioner is located indoors, and the condenser is connected to the outdoors through an exhaust pipe.

17. The heat exchange system according to claim 15, characterized in that: The integrated air conditioner is installed in a suspended ceiling, and the shell has a recessed clearance groove, which is used to cooperate with the keel of the ceiling, so that the shell is at least partially located above the ceiling.

18. The heat exchange system according to claim 15, 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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