Composite multifunctional heat exchange system and heat exchange method

Abstract

The invention provides a composite multifunctional heat exchange system and a heat exchange method.The composite multifunctional heat exchange system comprises a main heat exchange circulation loop and an auxiliary heat exchange circulation loop, and a main compressor, a main condenser, a main liquid storage device, a main expansion valve and a main evaporator are sequentially arranged on the main heat exchange circulation loop; an auxiliary compressor, an auxiliary four-way reversing valve exhaust channel, an auxiliary external heat exchanger, an auxiliary expansion valve, an auxiliary heat exchange pipe and an auxiliary four-way reversing valve air return channel are sequentially arranged on the auxiliary heat exchange circulation loop, a conventional heat exchange area and a composite heat exchange area are arranged in the main condenser, and a small-diameter heat exchange pipe is arranged in the conventional heat exchange area. A large-diameter heat exchange pipe is arranged in the composite heat exchange area, a small-diameter heat exchange pipe is communicated with the large-diameter heat exchange pipe through a reducer pipe, an auxiliary heat exchange pipe penetrates into the large-diameter heat exchange pipe, a main refrigerant circulates and flows back in the main heat exchange circulation loop, an auxiliary refrigerant circulates and flows back in the auxiliary heat exchange circulation loop, and the auxiliary refrigerant flows into the auxiliary heat exchange pipe. And a main refrigerant flows through an annular gap between the auxiliary heat exchange tube and the large-diameter heat exchange tube.

Description

Technical Field

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

[0002] As global ambient temperatures continue to rise, the design conditions of traditional refrigeration units have gradually become unable to adapt to actual operating needs, especially in high-temperature environments. The original units have difficulty maintaining stable and efficient refrigeration effects due to insufficient heat exchange efficiency and limited supercooling capacity. At the same time, the refrigeration market has an increasingly urgent demand for ultra-low temperature refrigeration (such as deep-cold storage, special industrial processes, etc.), but the existing technology still has shortcomings in the refrigeration depth and reliability under ultra-low temperature conditions. In addition, the requirements for the accuracy of temperature zone control in various fields continue to increase. The traditional single-circulation heat exchange system lacks a flexible regional adjustment mechanism and cannot achieve refined temperature control in local areas, resulting in energy waste or temperature fluctuations.

[0003] On the other hand, existing composite refrigeration systems are too bulky and take up a lot of space. They also require re-molding, consuming production resources. In winter, when using thermal fluorine defrosting, existing refrigeration systems often suffer from insufficient heat to defrost. This results in low condensing pressure and temperature, making defrosting impossible.

[0004] The combination of the above problems has caused the existing refrigeration system to face significant bottlenecks when dealing with complex environments, diverse demands and fine control scenarios. There is an urgent need for a composite multifunctional heat exchange system that can adapt to a wide ambient temperature range, meet ultra-low temperature requirements and support regional precise control. Summary of the Invention

[0005] The purpose of the present invention is to address the above-mentioned problems in the existing technology and to propose a composite multifunctional heat exchange system and heat exchange method.

[0006] The objectives of the present invention can be achieved through the following technical solutions: A composite multifunctional heat exchange system includes a main heat exchange circulation loop and an auxiliary heat exchange circulation loop, wherein a main compressor, a main condenser, a main liquid reservoir, a main expansion valve, and a main evaporator are sequentially arranged on the main heat exchange circulation loop, and an auxiliary compressor, an exhaust channel of an auxiliary four-way reversing valve, an auxiliary external heat exchanger, an auxiliary expansion valve, an auxiliary heat exchange pipe, and a return air channel of the auxiliary four-way reversing valve are sequentially arranged on the auxiliary heat exchange circulation loop, a conventional heat exchange area and a composite heat exchange area are arranged in the main condenser, a small-diameter heat exchange pipe is arranged in the conventional heat exchange area, and a large-diameter heat exchange pipe is arranged in the composite heat exchange area, the small-diameter heat exchange pipe is connected to the large-diameter heat exchange pipe through a reducing pipe, and the auxiliary heat exchange pipe penetrates into the large-diameter heat exchange pipe, a main refrigerant circulates back in the main heat exchange circulation loop, and an auxiliary refrigerant circulates back in the auxiliary heat exchange circulation loop, the auxiliary refrigerant flows through the auxiliary heat exchange pipe, and the main refrigerant flows through the annular gap between the auxiliary heat exchange pipe and the large-diameter heat exchange pipe.

[0007] In the above-mentioned composite multifunctional heat exchange system, a main oil separator is also connected in series to the main heat exchange circulation loop between the main compressor and the main condenser; a main solenoid valve is also connected in series to the main heat exchange circulation loop between the main liquid reservoir and the main expansion valve; and a main gas-liquid separator is also connected in series to the main heat exchange circulation loop between the main evaporator and the main compressor.

[0008] In the above-mentioned composite multifunctional heat exchange system, one end of the reducer is a small-diameter opening, and the other end is a large-diameter opening, gradually transitioning from the small-diameter opening to the large-diameter opening; the small-diameter heat exchange tube is connected to the small-diameter opening of the reducer, and the center of the small-diameter heat exchange tube coincides with the center of the small-diameter opening; the large-diameter heat exchange tube is connected to the large-diameter opening of the reducer, and the center of the large-diameter heat exchange tube coincides with the center of the large-diameter opening.

[0009] In the above-mentioned composite multifunctional heat exchange system, the center of the auxiliary heat exchange tube coincides with the center of the large-diameter heat exchange tube.

[0010] In the above-mentioned composite multifunctional heat exchange system, the hydraulic diameter of the small-diameter heat exchange tube is equal to the hydraulic diameter of the annular gap, as shown in the following formula:

[0011]

[0012] So: D2=2D1+D3

[0013] Among them, D1 is the diameter of the small-diameter heat exchange tube in the main condenser, which is a known parameter; D3 is the diameter of the pipeline of the auxiliary external heat exchanger, which is also a known parameter; from this, the value of the diameter D2 of the large-diameter heat exchange tube can be calculated.

[0014] A heat exchange method for a composite multifunctional heat exchange system, applied to the composite multifunctional heat exchange system, includes the following contents:

[0015] A. When the heat exchange system is at a high ambient temperature, the auxiliary heat exchange loop is in cooling mode. The auxiliary refrigerant in the auxiliary heat exchange tube absorbs the heat of the main refrigerant in the annular gap. The auxiliary refrigerant is converted from a low-temperature, low-pressure gas-liquid two-phase state to a low-temperature, low-pressure gas state, and the main refrigerant is converted from a high-temperature, high-pressure gas-liquid two-phase state to a supercooled, high-pressure liquid state.

[0016] B. When the heat exchange system is at normal ambient temperature, the auxiliary heat exchange loop is in cooling mode. The auxiliary refrigerant in the auxiliary heat exchange tube absorbs the heat of the main refrigerant in the annular gap. The auxiliary refrigerant is converted from low-temperature and low-pressure gas-liquid two-phase to low-temperature and low-pressure gas, and the main refrigerant is converted from high-temperature and high-pressure liquid to supercooled high-pressure liquid.

[0017] C. When the heat exchange system is at a low ambient temperature, the condensing pressure and condensing temperature of the heat exchange system decrease. In order to provide the heat required for hot fluorine defrosting, the auxiliary heat exchange circulation loop is opened, and the auxiliary four-way reversing valve is driven to reverse, so that the auxiliary heat exchange circulation loop is in heating mode. The auxiliary refrigerant in the auxiliary heat exchange tube releases heat to the main refrigerant in the annular gap. The auxiliary refrigerant is converted from high-temperature and high-pressure gas to high-temperature and high-pressure liquid. The main refrigerant absorbs the heat released by the auxiliary refrigerant and its temperature rises.

[0018] In the heat exchange method of the above-mentioned composite multifunctional heat exchange system, in step A, the high ambient temperature specifically refers to a temperature exceeding 40°C, the temperature of the main refrigerant before passing through the composite heat exchange area is above 55°C, and the temperature of the main refrigerant after passing through the composite heat exchange area is below 40°C.

[0019] In the heat exchange method of the above-mentioned composite multifunctional heat exchange system, in step B, the normal ambient temperature range is 10-40°C, the temperature of the main refrigerant before passing through the composite heat exchange area is 25-55°C, and the temperature of the main refrigerant after passing through the composite heat exchange area is 10-25°C.

[0020] In the heat exchange method of the above-mentioned composite multifunctional heat exchange system, in step C, the low ambient temperature specifically refers to a temperature below 10°C, a condensation temperature below 25°C, a temperature of the main refrigerant below 25°C before passing through the composite heat exchange area, and a temperature increase of 20 to 30°C after the main refrigerant passes through the composite heat exchange area.

[0021] In the heat exchange method of the composite multifunctional heat exchange system, the evaporation temperature of the auxiliary heat exchange circulation loop is 0-10°C during cooling, and the condensation temperature is 40-50°C during heating.

[0022] Compared with the existing technology, this composite multifunctional heat exchange system and heat exchange method has the following beneficial effects:

[0023] 1. Improve heat exchange efficiency

[0024] The system sets up conventional heat exchange areas and composite heat exchange areas in the main condenser, and combines the layout design of small-diameter heat exchange tubes and large-diameter heat exchange tubes. When the main refrigerant passes through the composite heat exchange area, it further utilizes the auxiliary refrigerant to achieve deep heat exchange, allowing the main refrigerant to obtain higher cooling capacity, thereby optimizing the cooling effect and improving cooling efficiency.

[0025] 2. Multifunctional heating and cooling applications

[0026] This system features versatile heat exchange capabilities that adapt to varying ambient temperature conditions. In high ambient temperatures, the auxiliary heat exchange circuit effectively reduces the condensing pressure and temperature of the main system, ensuring its normal operation. In normal ambient temperatures, the auxiliary heat exchange circuit lowers the temperature of the main refrigerant, improving cooling efficiency and increasing the system's cooling capacity. In low ambient temperatures, the system uses the auxiliary heat exchange circuit to defrost with hot fluorine, preventing frost and ensuring continuous and stable system operation.

[0027] 3. Energy saving and improved refrigeration efficiency

[0028] By using an auxiliary heat exchange circuit to lower the temperature of the main refrigerant at normal ambient temperatures, the main refrigerant can achieve a greater degree of subcooling after throttling by the expansion valve. This optimizes the dryness of the refrigerant and increases the cooling capacity per unit mass of refrigerant. This energy-saving method helps reduce system energy consumption and improve cooling efficiency.

[0029] 4. Structural design optimization

[0030] The concentric arrangement of auxiliary heat exchange tubes and large-diameter heat exchange tubes ensures a uniform annular radius, ensuring the flow stability of the main refrigerant and improving heat transfer uniformity. This inner-outer-outer design not only improves fluid dynamics but also optimizes heat transfer efficiency.

[0031] 5. Efficiently solve the problem of hot fluorine defrosting in low temperature environment

[0032] This system can provide sufficient heat to the main system under low ambient temperature conditions through the heating effect of the auxiliary heat exchange circuit, preventing frost on the main evaporator and ensuring the stability of the equipment in low temperature environments. By using the auxiliary heat exchange tube as a condenser in low temperature conditions, the temperature of the main refrigerant can be effectively increased, ensuring that the main system has sufficient heat for hot fluorine defrosting.

[0033] 6. Adapt to different operating conditions

[0034] This composite, multifunctional heat exchange system flexibly adjusts its operating mode (such as cooling or heating) based on varying ambient temperatures, maximizing system adaptability and stability. Particularly in environments with large temperature fluctuations, the system's self-regulating capabilities enable it to maintain high performance.

[0035] In summary, the composite multifunctional heat exchange system not only maintains efficient operation under diverse environmental conditions, but also improves energy efficiency, reduces energy consumption, and enhances equipment stability and reliability. These benefits give the system significant advantages in practical applications, especially in scenarios with high requirements for heat exchange efficiency and energy efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of the overall structure of this composite multifunctional heat exchange system.

[0037] Figure 2 This is the internal structure diagram of the main condenser in this composite multifunctional heat exchange system.

[0038] Figure 3 This is the structural diagram of the composite casing in this composite multifunctional heat exchange system.

[0039] Figure 4 This is a block diagram of the main refrigerant heat exchange cycle of the main heat exchange cycle loop in the heat exchange method of the present invention.

[0040] Figure 5 The figure is a block diagram of an auxiliary refrigerant refrigeration cycle of an auxiliary heat exchange circulation loop in the heat exchange method of the present invention.

[0041] Figure 6 This is a block diagram of an auxiliary refrigerant heating cycle of the auxiliary heat exchange circulation loop in the heat exchange method of the present invention.

[0042] In the figure, 1. main compressor; 2. main oil separator; 3. main condenser; 3a. small-diameter heat exchange tube; 3b. reducing tube; 3c. large-diameter heat exchange tube; 4. main liquid reservoir; 5. main solenoid valve; 6. main expansion valve; 7. main evaporator; 8. main gas-liquid separator; 9. auxiliary compressor; 10. auxiliary four-way reversing valve; 11. auxiliary external heat exchanger; 12. auxiliary expansion valve; 13. auxiliary heat exchange tube. DETAILED DESCRIPTION

[0043] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0044] like Figures 1 to 3As shown, the composite multifunctional heat exchange system includes a main heat exchange circulation loop and an auxiliary heat exchange circulation loop. The main heat exchange circulation loop is sequentially provided with a main compressor 1, a main oil separator 2, a main condenser 3, a main liquid storage 4, a main solenoid valve 5, a main expansion valve 6, a main evaporator 7 and a main gas-liquid separator 8. The auxiliary heat exchange circulation loop is sequentially arranged with an auxiliary compressor 9, an exhaust passage of an auxiliary four-way reversing valve 10, an auxiliary external heat exchanger 11, an auxiliary expansion valve 12, an auxiliary heat exchange pipe 13 and a return air passage of the auxiliary four-way reversing valve 10. A conventional heat exchange area and a composite heat exchange area are provided in the main condenser 3. A small-diameter heat exchange pipe 3a is provided in the conventional heat exchange area, and a large-diameter heat exchange pipe 3c is provided in the composite heat exchange area. The small-diameter heat exchange pipe 3a is connected to the large-diameter heat exchange pipe 3c through a reducer 3b, wherein the reducer 3b is specifically a copper pipe. The auxiliary heat exchange tube 13 penetrates into the large diameter heat exchange tube 3c, the main refrigerant circulates back in the main heat exchange circulation loop, the auxiliary refrigerant circulates back in the auxiliary heat exchange circulation loop, the auxiliary refrigerant flows through the auxiliary heat exchange tube 13, and the main refrigerant flows through the annular gap between the auxiliary heat exchange tube 13 and the large diameter heat exchange tube 3c.

[0045] like Figure 2 and 3 As shown, preferably, one end of the reducing tube 3b has a small diameter opening and the other end has a large diameter opening, with a gradual transition from the small diameter opening to the large diameter opening. The small-diameter heat exchange tube 3a connects to the small-diameter opening of the reducing tube 3b, with the center of the small-diameter heat exchange tube 3a coinciding with the center of the small-diameter opening. The large-diameter heat exchange tube 3c connects to the large-diameter opening of the reducing tube 3b, with the center of the large-diameter heat exchange tube 3c coinciding with the center of the large-diameter opening. The reducing tube 3b gradually increases the flow rate of the small-diameter heat exchange tube 3a and transitions it to the large-diameter heat exchange tube 3c, thereby achieving a smooth transition of the main refrigerant and improving the stability of the refrigerant cycle.

[0046] Preferably, the center of the auxiliary heat exchange tube 13 coincides with the center of the large-diameter heat exchange tube 3c. The auxiliary heat exchange tube 13 and the large-diameter heat exchange tube 3c are arranged in an inner-outer arrangement and concentrically with each other. This ensures a uniform annular radius between the auxiliary heat exchange tube 13 and the large-diameter heat exchange tube 3c, ensuring the stability of the main refrigerant flow and improving heat exchange uniformity.

[0047] Preferably, in order to ensure that the flow state of the main refrigerant in the conventional heat exchange area and the composite heat exchange area of ​​the main condenser 3 is similar, the hydraulic diameter of the small-diameter heat exchange tube 3a is equal to the hydraulic diameter of the annular gap, as shown in the following formula:

[0048]

[0049] So: D2=2D1+D3

[0050] Where D1 is the diameter of the small-diameter heat exchange tube 3a in the main condenser 3, which is a known parameter; D3 is the diameter of the pipeline of the auxiliary external heat exchanger, which is also a known parameter; from this, the value of the diameter D2 of the large-diameter heat exchange tube 3c can be calculated.

[0051] like Figures 4 to 6 As shown, a heat exchange method of a composite multifunctional heat exchange system is applied to the above composite multifunctional heat exchange system, including the following contents:

[0052] like Figure 4 and 5 As shown, A. When the heat exchange system is at a high ambient temperature, the auxiliary heat exchange circulation loop is in the cooling mode, and the auxiliary heat exchange tube 13 in the main condenser 3 is equivalent to the evaporator function of the auxiliary system. The auxiliary refrigerant in the auxiliary heat exchange tube 13 absorbs the heat of the main refrigerant in the annular gap, and the auxiliary refrigerant is converted from a low-temperature and low-pressure gas-liquid two-phase to a low-temperature and low-pressure gas, and the main refrigerant is converted from a high-temperature and high-pressure gas-liquid two-phase to a supercooled high-pressure liquid; that is, the evaporation of the auxiliary refrigerant in the auxiliary system is completed, and the main refrigerant gas of the main system is liquefied, thereby reducing the condensation pressure and temperature, and ensuring the normal operation of the main system.

[0053] High ambient temperature specifically means a temperature exceeding 40°C, a temperature of the main refrigerant before passing through the composite heat exchange area is above 55°C, and a temperature of the main refrigerant after passing through the composite heat exchange area is below 40°C.

[0054] like Figure 4 and 5 As shown, B. When the heat exchange system is at normal ambient temperature, the auxiliary heat exchange circulation loop is in cooling mode, and the auxiliary heat exchange tube 13 in the main condenser 3 is equivalent to the evaporator function of the auxiliary system. The auxiliary refrigerant in the auxiliary heat exchange tube 13 absorbs the heat of the main refrigerant in the annular gap, and the auxiliary refrigerant is converted from low-temperature and low-pressure gas-liquid two-phase to low-temperature and low-pressure gas, and the main refrigerant is converted from high-temperature and high-pressure liquid to supercooled high-pressure liquid; that is, the evaporation of the auxiliary refrigerant in the auxiliary system is completed, and the main refrigerant of the main system is assisted to cool down. As the temperature of the main refrigerant decreases, the liquid supply of the main system can obtain a greater degree of supercooling. After the main expansion valve 6 is throttled, the dryness of the main refrigerant becomes smaller, and the refrigeration efficiency is improved.

[0055] Dryness refers to the ratio of liquid to vapor phases per unit mass of refrigerant, ranging from 0 to 1, with 0 indicating a completely liquid refrigerant and 1 indicating a completely saturated vapor phase. The lower the dryness, the higher the proportion of liquid phase. A lower dryness after throttling increases the proportion of liquid refrigerant. A higher liquid proportion allows the evaporator to absorb more heat, resulting in greater cooling capacity. This allows the same equipment to achieve greater cooling capacity, thus being considered a method of energy conservation. Different refrigerants exhibit varying performance under different operating conditions. For R404a, operating at -25°C, condensing at 45°C, and a superheat of 8K, the dryness of the refrigerant after throttling is 0.505 at a subcooling of 5K, and the cooling capacity per unit mass is 100.5 kJ / kg. At a subcooling of 25K, the dryness after throttling is 0.34, and the cooling capacity per unit mass is 131.8 kJ / kg. This increases cooling capacity by 31.1%.

[0056] The normal ambient temperature range is 10-40°C, the temperature of the main refrigerant before passing through the composite heat exchange area is 25-55°C, and the temperature of the main refrigerant after passing through the composite heat exchange area is 10-25°C.

[0057] like Figure 4 and 6 As shown, C. When the heat exchange system is in a low ambient temperature, the condensing pressure and condensing temperature of the heat exchange system are reduced, and hot fluorine defrosting occurs at the main evaporator 7. When the evaporating temperature is lower than 0°C, frosting occurs. In order to provide the required heat for hot fluorine defrosting, the auxiliary heat exchange circulation loop is opened, and the auxiliary four-way reversing valve 10 is driven to reverse, so that the auxiliary heat exchange circulation loop is in heating mode. The auxiliary heat exchange pipe 13 in the main condenser 3 is equivalent to the condenser function of the auxiliary system. The auxiliary refrigerant in the auxiliary heat exchange pipe 13 releases heat to the main refrigerant in the annular gap, and the auxiliary refrigerant is converted from high-temperature and high-pressure gas to high-temperature and high-pressure liquid. The main refrigerant absorbs the heat released by the auxiliary refrigerant and its temperature rises; that is, the condensation of the auxiliary refrigerant in the auxiliary system is completed, and the temperature of the main refrigerant in the main system is increased, so that the temperature of the refrigerant used for hot fluorine defrosting in the main system is increased, so that there is sufficient heat for defrosting.

[0058] Low ambient temperature refers to temperatures below 10°C and condensing temperatures below 25°C. The condensing pressure varies depending on the type of refrigerant. The temperature of the main refrigerant is below 25°C before passing through the composite heat exchange area, and the temperature of the main refrigerant increases by 20-30°C after passing through the composite heat exchange area.

[0059] Preferably, the auxiliary heat exchange circulation loop adopts the cooling or heating parameters of the air-conditioning working condition, the evaporation temperature is 0-10°C during cooling, and the condensation temperature is 40-50°C during heating.

[0060] Both the main system and the auxiliary system can adopt variable frequency mode to better match different operating conditions.

[0061] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art of the invention may make various modifications or additions to the described specific embodiments or replace them in a similar manner, but will not deviate from the spirit of the invention or exceed the defined scope. Although the present invention has been described and described in detail in the foregoing description, such descriptions and descriptions are considered to be illustrative or exemplary rather than restrictive. It should be understood that within the scope of the following claims, changes and modifications may be made by those of ordinary skill in the art. Specifically, the present invention encompasses additional embodiments having any combination of features from the different embodiments described above. With respect to the use of the expression "generally" or "substantially", this patent application should be understood to disclose that these features and values ​​are also fully met, i.e., there is no aforementioned characterization as "generally" or "substantially".

[0062] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

Claims

1. A composite multifunctional heat exchange system, comprising a main heat exchange circulation loop and an auxiliary heat exchange circulation loop, wherein the main heat exchange circulation loop is sequentially provided with a main compressor, a main condenser, a main liquid reservoir, a main expansion valve, and a main evaporator, and the auxiliary heat exchange circulation loop is sequentially provided with an auxiliary compressor, an exhaust passage of an auxiliary four-way reversing valve, an auxiliary external heat exchanger, an auxiliary expansion valve, an auxiliary heat exchange pipe, and a return air passage of the auxiliary four-way reversing valve, characterized in that: A conventional heat exchange area and a composite heat exchange area are provided in the main condenser. A small-diameter heat exchange tube is provided in the conventional heat exchange area, and a large-diameter heat exchange tube is provided in the composite heat exchange area. The small-diameter heat exchange tube is connected to the large-diameter heat exchange tube through a reducing tube, and the auxiliary heat exchange tube penetrates into the large-diameter heat exchange tube. The main refrigerant circulates back in the main heat exchange circulation loop, and the auxiliary refrigerant circulates back in the auxiliary heat exchange circulation loop. The auxiliary refrigerant flows through the auxiliary heat exchange tube, and the main refrigerant flows through the annular gap between the auxiliary heat exchange tube and the large-diameter heat exchange tube.

2. The composite multifunctional heat exchange system according to claim 1, characterized in that: A main oil separator is also connected in series to the main heat exchange circulation loop between the main compressor and the main condenser; a main solenoid valve is also connected in series to the main heat exchange circulation loop between the main liquid reservoir and the main expansion valve; and a main gas-liquid separator is also connected in series to the main heat exchange circulation loop between the main evaporator and the main compressor.

3. The composite multifunctional heat exchange system according to claim 1, characterized in that: One end of the reducer is a small-diameter opening, and the other end is a large-diameter opening, gradually transitioning from the small-diameter opening to the large-diameter opening; the small-diameter heat exchange tube is connected to the small-diameter opening of the reducer, and the center of the small-diameter heat exchange tube coincides with the center of the small-diameter opening; the large-diameter heat exchange tube is connected to the large-diameter opening of the reducer, and the center of the large-diameter heat exchange tube coincides with the center of the large-diameter opening.

4. The composite multifunctional heat exchange system according to claim 1, characterized in that: The center of the auxiliary heat exchange tube coincides with the center of the large-diameter heat exchange tube.

5. The composite multifunctional heat exchange system according to claim 4, characterized in that: The hydraulic diameter of the small-diameter heat exchange tube is equal to the hydraulic diameter of the annular gap, as shown in the following formula: So: D2=2D1+D3 Among them, D1 is the diameter of the small-diameter heat exchange tube in the main condenser, which is a known parameter; D3 is the diameter of the pipeline of the auxiliary external heat exchanger, which is also a known parameter; from this, the value of the diameter D2 of the large-diameter heat exchange tube can be calculated.

6. A heat exchange method for a composite multifunctional heat exchange system, applied to the composite multifunctional heat exchange system according to any one of claims 1 to 5, characterized in that: Includes the following: A. When the heat exchange system is at a high ambient temperature, the auxiliary heat exchange loop is in cooling mode. The auxiliary refrigerant in the auxiliary heat exchange tube absorbs the heat of the main refrigerant in the annular gap. The auxiliary refrigerant is converted from a low-temperature, low-pressure gas-liquid two-phase state to a low-temperature, low-pressure gas state, and the main refrigerant is converted from a high-temperature, high-pressure gas-liquid two-phase state to a supercooled, high-pressure liquid state. B. When the heat exchange system is at normal ambient temperature, the auxiliary heat exchange loop is in cooling mode. The auxiliary refrigerant in the auxiliary heat exchange tube absorbs the heat of the main refrigerant in the annular gap. The auxiliary refrigerant is converted from low-temperature and low-pressure gas-liquid two-phase to low-temperature and low-pressure gas, and the main refrigerant is converted from high-temperature and high-pressure liquid to supercooled high-pressure liquid. C. When the heat exchange system is at a low ambient temperature, the condensing pressure and condensing temperature of the heat exchange system decrease. In order to provide the heat required for hot fluorine defrosting, the auxiliary heat exchange circulation loop is opened, and the auxiliary four-way reversing valve is driven to reverse, so that the auxiliary heat exchange circulation loop is in heating mode. The auxiliary refrigerant in the auxiliary heat exchange tube releases heat to the main refrigerant in the annular gap. The auxiliary refrigerant is converted from high-temperature and high-pressure gas to high-temperature and high-pressure liquid. The main refrigerant absorbs the heat released by the auxiliary refrigerant and its temperature rises.

7. The heat exchange method of the composite multifunctional heat exchange system according to claim 6, characterized in that: In step A, the high ambient temperature specifically refers to a temperature exceeding 40°C, the temperature of the main refrigerant before passing through the composite heat exchange area is above 55°C, and the temperature of the main refrigerant after passing through the composite heat exchange area is below 40°C.

8. The heat exchange method of the composite multifunctional heat exchange system according to claim 6, characterized in that: In step B, the normal ambient temperature range is 10-40°C, the temperature of the main refrigerant before passing through the composite heat exchange area is 25-55°C, and the temperature of the main refrigerant after passing through the composite heat exchange area is 10-25°C.

9. The heat exchange method of the composite multifunctional heat exchange system according to claim 6, characterized in that: In step C, the low ambient temperature specifically refers to a temperature below 10°C, a condensing temperature below 25°C, a temperature of the main refrigerant below 25°C before passing through the composite heat exchange area, and a temperature increase of 20 to 30°C after the main refrigerant passes through the composite heat exchange area.

10. The heat exchange method of the composite multifunctional heat exchange system according to claim 6, characterized in that: The evaporation temperature of the auxiliary heat exchange circulation loop is 0-10°C during cooling, and the condensation temperature is 40-50°C during heating.

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