Refrigerating system and environmental test box

Abstract

The embodiment of the invention discloses a refrigerating system and an environment test box. The refrigerating system comprises a high-temperature-section refrigerating cycle system, a low-temperature-section refrigerating cycle system and an evaporative condenser. The high-temperature section refrigeration cycle system and the low-temperature section refrigeration cycle system are connected through an evaporative condenser; the high-temperature section refrigeration cycle system uses R448A as a refrigerant for refrigeration cycle, and the low-temperature section refrigeration cycle system uses R473A as a refrigerant for refrigeration cycle. Traditional refrigerant combinations R404A and R23 are replaced by a combination of R448A and R473A which are lower in global warming potential, the technical problem that in the prior art, the global warming potential of a refrigerating system is high is solved, the technical effect that the refrigerating system not only can conduct ultralow-temperature refrigeration, but also has the low global warming potential is achieved, and the refrigerating system can be used for refrigerating at a low temperature. And the energy use efficiency of the refrigerating system is improved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of refrigeration cycles, and in particular to a refrigeration system and an environmental test chamber. Background Art

[0002] Due to the new EU F-gas (Fluorinated Greenhouse Gases) regulation amendment, from January 1, 2025, the global warming potential (GWP) of stationary fluorinated refrigeration equipment operating at temperatures above -50°C must be ≤2500.

[0003] Currently, the primary refrigerants in cascade systems for high and low temperature environmental test chambers are R404A / R23. The GWPs of R404A and R23 are 3943 and 14800, respectively, both exceeding the new EU F-gas requirement of 2500 and limiting their long-term viability. Therefore, a new refrigerant combination must be developed for cascade refrigeration systems in environmental test chambers to ensure compliance with the new EU F-gas regulations. Summary of the Invention

[0004] The embodiments of the present invention provide a refrigeration system and an environmental test chamber, which solve the technical problem of high global warming potential of refrigeration systems in the prior art.

[0005] An embodiment of the present invention provides a refrigeration system, which includes a high-temperature refrigeration cycle system, a low-temperature refrigeration cycle system, and an evaporative condenser;

[0006] The high-temperature section refrigeration cycle system and the low-temperature section refrigeration cycle system are connected via the evaporative condenser;

[0007] The high-temperature section refrigeration cycle system uses R448A as a refrigerant to perform a refrigeration cycle, and the low-temperature section refrigeration cycle system uses R473A as a refrigerant to perform a refrigeration cycle.

[0008] Furthermore, the low-temperature section refrigeration cycle system includes a low-temperature stage compressor and a set evaporator;

[0009] The outlet of the low-temperature stage compressor is connected to the first inlet of the evaporative condenser; the first outlet of the evaporative condenser is connected to the inlet of the set evaporator through a set pipeline; the outlet of the set evaporator is connected to the inlet of the low-temperature stage compressor;

[0010] The heat exchange area of the set evaporator is greater than the set area value.

[0011] Furthermore, the low-temperature section refrigeration cycle system further includes a pre-cooling condenser, which is arranged between the outlet of the low-temperature stage compressor and the first inlet of the evaporative condenser.

[0012] Furthermore, the high-temperature section refrigeration cycle system includes a high-temperature compressor, a condenser and a high-temperature evaporator;

[0013] The high-temperature evaporator is connected in parallel with the evaporative condenser;

[0014] The outlet of the high-temperature compressor is connected to the inlet of the condenser; the outlet of the condenser is respectively connected to the inlet of the high-temperature evaporator and the second inlet of the evaporative condenser; the outlet of the high-temperature evaporator and the second outlet of the evaporative condenser are both connected to the inlet of the high-temperature compressor.

[0015] Furthermore, the setting pipeline includes at least a first branch and a second branch;

[0016] The first outlet of the evaporative condenser is connected to the first inlet and the second inlet of the set evaporator through the first branch and the second branch respectively.

[0017] Furthermore, the low-temperature section refrigeration cycle system further includes an expansion tank;

[0018] The inlet of the expansion tank is connected to the first inlet of the evaporative condenser, and the outlet of the expansion tank is connected to the inlet of the low-temperature stage compressor.

[0019] Furthermore, the low-temperature section refrigeration cycle system further includes a first hot bypass circuit and a first cold bypass circuit;

[0020] One end of the first thermal bypass loop is connected to the first inlet of the evaporative condenser, and the other end of the first thermal bypass loop is connected to the inlet of the low-temperature stage compressor;

[0021] The first thermal bypass circuit is provided with a solenoid valve and an energy regulating device in sequence;

[0022] One end of the first cold bypass loop is connected to the first outlet of the evaporative condenser, and the other end of the first cold bypass loop is connected to the inlet of the low-temperature compressor;

[0023] The first cold bypass circuit is provided with a solenoid valve and an expansion valve in sequence.

[0024] Furthermore, the high temperature section refrigeration cycle system further includes a second hot bypass circuit and a second cold bypass circuit;

[0025] One end of the second thermal bypass loop is connected to the inlet of the condenser, and the other end of the second thermal bypass loop is connected to the inlet of the high-temperature stage compressor;

[0026] The second thermal bypass circuit is provided with a solenoid valve and an energy regulating device in sequence;

[0027] One end of the second cold bypass loop is connected to the outlet of the condenser, and the other end of the second cold bypass loop is connected to the inlet of the high-temperature stage compressor;

[0028] The second cold bypass circuit is provided with a solenoid valve and an expansion valve in sequence.

[0029] Furthermore, the refrigeration system further includes a pressure controller;

[0030] The pressure controller is electrically connected to the low-temperature stage compressor in the low-temperature section refrigeration cycle system and the high-temperature stage compressor in the high-temperature section refrigeration cycle system;

[0031] The pressure controller is configured to control the corresponding compressor to stop running or open a pressure relief valve to relieve pressure when it is detected that the pressure of the low-temperature compressor or the high-temperature compressor exceeds a standard.

[0032] An embodiment of the present invention further provides an environmental test chamber, which includes the refrigeration system in any of the above embodiments.

[0033] An embodiment of the present invention discloses a refrigeration system and an environmental test chamber. The refrigeration system includes a high-temperature refrigeration cycle system, a low-temperature refrigeration cycle system, and an evaporative condenser. The high-temperature refrigeration cycle system and the low-temperature refrigeration cycle system are connected via the evaporative condenser. The high-temperature refrigeration cycle system uses R448A as a refrigerant for a refrigeration cycle, and the low-temperature refrigeration cycle system uses R473A as a refrigerant for a refrigeration cycle. The present invention solves the technical problem of the high global warming potential of the refrigeration system in the prior art by replacing the traditional refrigerant combination of R404A and R23 with the combination of R448A and R473A, which has a lower global warming potential. This achieves the technical effect of not only being able to perform ultra-low temperature refrigeration but also having a low global warming potential, thereby improving the energy efficiency of the refrigeration system. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a structural diagram of a refrigeration system provided by an embodiment of the present invention;

[0035] Figure 2 This is a system principle diagram of a refrigeration system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0037] It should be noted that the terms "first," "second," and so on, in the specification, claims, and drawings of the present invention are used to distinguish different objects, and are not intended to limit a specific order. The following embodiments of the present invention can be implemented independently or in combination with each other, and the present invention does not impose specific limitations on this.

[0038] Figure 1 This is a structural diagram of a refrigeration system provided by an embodiment of the present invention.

[0039] like Figure 1 As shown, the refrigeration system includes a high-temperature refrigeration cycle system 10, a low-temperature refrigeration cycle system 20 and an evaporative condenser 30; the high-temperature refrigeration cycle system 10 and the low-temperature refrigeration cycle system 20 are connected through the evaporative condenser 30.

[0040] The high-temperature refrigeration cycle system 10 uses R448A as a refrigerant to perform a refrigeration cycle, and the low-temperature refrigeration cycle system 20 uses R473A as a refrigerant to perform a refrigeration cycle.

[0041] Specifically, conventional ultra-low temperature refrigeration systems typically use a combination of R404A and R23 refrigerants. However, the global warming potential (GWP) of R404A and R23 is high, failing to meet the new EU F-gas regulations. R448A, on the other hand, has a lower GWP of approximately 1273, while R473A has a GWP of approximately 1800, significantly lower than R404A's 3943 and R23's 14800. Table 1 details the composition, physical properties, environmental performance, and safety of refrigerants R404A, R448A, R23, and R473A.

[0042] Table 1. Refrigerant performance table

[0043]

[0044] As shown in Table 1, refrigerants R448A and R404A share similar boiling points, critical temperatures, and pressures, as well as the same Ozone Depletion Potential (ODP). However, R448A's GWP is 1273, while R404A's is approximately 3943, representing a 67.7% reduction in its GWP compared to R404. Meanwhile, refrigerants R473A and R23 share similar boiling points, critical temperatures, and pressures, as well as the same ODP. However, R473A's GWP is 1800, while R23's is a whopping 14800. Therefore, both R448A and R473A meet the new EU F-gas regulations and are more environmentally friendly.

[0045] In the embodiment of the present invention, by using a mixed refrigerant combination of R448A and R473A, based on the characteristics of R448A and R473A, the following advantages exist: (1) Good environmental performance. The GWP of both refrigerants is lower than that of traditional refrigerants, which can effectively reduce the impact of the greenhouse effect on the environment and comply with environmental protection regulations; (2) Low refrigeration temperature. By cascading, the low-temperature performance of R473A is fully utilized to achieve ultra-low temperature refrigeration (-80°C), meeting some application scenarios with strict low-temperature requirements; (3) High energy efficiency. The good energy efficiency performance of R448A at high temperature is combined with the high efficiency refrigeration capacity of R473A at low temperature, so that the entire refrigeration system can maintain relatively high energy efficiency while achieving ultra-low temperature refrigeration, thereby improving the energy efficiency of the refrigeration system by 10% to 20%.

[0046] The present invention solves the technical problem of high global warming potential of refrigeration systems in the prior art by replacing the traditional refrigerant combination R404A and R23 with the combination of R448A and R473A, which has lower global warming potential. This achieves the technical effect that the refrigeration system is not only capable of ultra-low temperature refrigeration but also has a low global warming potential, thereby improving the energy utilization efficiency of the refrigeration system.

[0047] Figure 2 This is a system principle diagram of a refrigeration system provided by an embodiment of the present invention.

[0048] Alternatively, as Figure 2 As shown, the low-temperature refrigeration cycle system 20 includes a low-temperature compressor 21 and a set evaporator 22;

[0049] The outlet of the low-temperature stage compressor 21 is connected to the first inlet a of the evaporative condenser 30; the first outlet b of the evaporative condenser 30 is connected to the inlet of the set evaporator 22 through the set pipeline 31; the outlet of the set evaporator 22 is connected to the inlet of the low-temperature stage compressor 21; the heat exchange area of the set evaporator 22 is greater than the set area value.

[0050] Specifically, in the low-temperature refrigeration cycle system 20, R473A is used as the refrigerant. R473A absorbs the heat of the object to be cooled in the set evaporator 22 and evaporates into gas, which is sucked into the low-temperature compressor 21 and compressed into high-temperature and high-pressure gas. After entering the evaporative condenser 30, it is condensed into liquid by the refrigerant R448A in the high-temperature refrigeration cycle system 10, and then passes through the throttling element (i.e. Figure 2 After throttling and reducing the pressure through the solenoid valve m and expansion valve n) shown in FIG, the air enters the set evaporator 22 again to continue the refrigeration cycle.

[0051] It should be noted that, as can be seen from Table 1, the glide temperature of R473A is higher than that of R23. When a mixed refrigerant with a high glide temperature exchanges heat in the two-phase region of the evaporator 22, the gas is in a non-superheated state, resulting in certain energy losses and liquid hammer, which can affect the compressor. Therefore, the heat exchange area of the evaporator 22 needs to be appropriately increased. For example, the heat exchange area of the evaporator 22 can be designed to be 10-15% larger than that when using the refrigerant R23.

[0052] Alternatively, as Figure 2 As shown, the low-temperature refrigeration cycle system 20 further includes a pre-cooling condenser 23 , which is disposed between the outlet of the low-temperature stage compressor 21 and the first inlet a of the evaporative condenser 30 .

[0053] Specifically, since the exhaust temperature of the low-temperature refrigeration cycle system 20 can reach up to 130°C during normal operation, while the condensing temperature of the low-temperature refrigeration cycle system 20 is generally below -20°C, the difference between the two is too large, and the flow rate of R473A in the high-temperature state is extremely fast, and the time it passes through the plate heat exchanger (i.e., the evaporative condenser 30) is relatively short, there may be incomplete condensation. Therefore, a pre-cooling condenser 23 is provided so that the gas discharged from the low-temperature compressor 21 enters the pre-cooling condenser 23 before entering the evaporative condenser 30, and after the exhaust temperature is reduced to near room temperature (generally to 30-35°C), it enters the evaporative condenser 30 for condensation, thereby ensuring complete condensation and thus ensuring the cooling effect.

[0054] Optionally, the high-temperature refrigeration cycle system 10 includes a high-temperature compressor 11, a condenser 12, and a high-temperature evaporator 13; the high-temperature evaporator 13 is connected in parallel with the evaporative condenser 30;

[0055] The outlet of the high-temperature compressor 11 is connected to the inlet of the condenser 12; the outlet of the condenser 12 is respectively connected to the inlet of the high-temperature evaporator 13 and the second inlet c of the evaporative condenser 30; the outlet of the high-temperature evaporator 13 and the second outlet d of the evaporative condenser 30 are both connected to the inlet of the high-temperature compressor 11.

[0056] Specifically, a solenoid valve m and an expansion valve n are provided between the outlet of the condenser 12 and the inlet of the high-temperature evaporator 13 ; a solenoid valve m and an expansion valve n are also provided between the outlet of the condenser 12 and the second inlet c of the evaporative condenser 30 .

[0057] The high temperature section refrigeration cycle system 10 uses R448A as the refrigerant. R448A is compressed into high temperature and high pressure gas in the high temperature stage compressor 11, and then enters the condenser 12 and is condensed into high pressure liquid by the ambient cooling medium (such as air or water). Figure 2 The solenoid valve m and expansion valve n shown in the figure throttle and reduce the pressure to a low-temperature, low-pressure gas-liquid mixture, which enters the evaporative condenser 30. In the evaporative condenser 30, the R473A enters the evaporative condenser 30 by absorbing the heat of the low-temperature refrigeration cycle system 10 and evaporates. The R473A is then re-absorbed by the high-temperature compressor 11, completing a refrigeration cycle.

[0058] Furthermore, the provision of a branch circuit of high-temperature evaporator 13 enables humidity control of the environmental test chamber through the high-temperature refrigeration cycle system 10. Specifically, the surface temperature of high-temperature evaporator 13 achieves a lower dew point by reducing the refrigerant evaporation pressure. When air flows through this evaporator, its surface temperature falls below the air dew point, causing water vapor in the air to quickly condense into liquid water and be discharged. By adjusting the refrigerant flow rate of the branch evaporator (e.g., adjusting the opening of solenoid valve m or expansion valve n), the amount of condensation can be precisely controlled, thereby adjusting the humidity level.

[0059] It should be noted that when the temperature required for cooling is relatively low, the R448A in the high-temperature refrigeration cycle system 10 can fully meet the refrigeration needs of the relatively low-temperature segment, so the high-temperature refrigeration cycle system 10 can work alone to meet the refrigeration needs; when refrigeration is required to achieve an ultra-low temperature environment, the R448A in the high-temperature refrigeration cycle system 10 cannot meet the refrigeration needs of the ultra-low temperature segment. At this time, the high-temperature refrigeration cycle system 10 and the low-temperature refrigeration cycle system 20 are required to work together to achieve the ultra-low temperature refrigeration needs.

[0060] On the basis of the above technical solutions, for the refrigeration system using the combination of refrigerants R448A and R473A, since the operating pressure of R473A is relatively high, it is necessary to ensure that the operating high pressure of the low-temperature section refrigeration cycle system 20 and the low-temperature compressor 21 is within the safe value. At the same time, combined with the compression package and efficiency of the low-temperature compressor 21, the following refrigeration temperature conditions can be set: (1) When the box temperature is -40℃ to -50℃, the evaporation temperature can be -65℃, and the intermediate temperature can be -20℃; (2) When the box temperature is -50℃ to -60℃, the evaporation temperature can be -70℃, and the intermediate temperature can be -25℃; (3) When the box temperature is -60℃ to -70℃, the evaporation temperature can be -80℃, and the intermediate temperature can be -30℃. In practice, it can be adjusted in real time according to the temperature in the environmental test chamber.

[0061] Alternatively, as Figure 2 As shown, the setting pipeline 31 includes at least a first branch N1 and a second branch N2;

[0062] The first outlet b of the evaporative condenser 30 is connected to the first inlet e and the second inlet f of the set evaporator 22 through the first branch N1 and the second branch N2 respectively.

[0063] Specifically, both the first branch N1 and the second branch N2 are equipped with throttling elements, including a solenoid valve m and an expansion valve n. By configuring the set line 31 with multiple throttling elements connected in parallel, the refrigeration system can have different options under different refrigeration conditions. For example, when a refrigeration cycle with a certain temperature is required, either the first branch N1 or the second branch N2 can be opened to allow refrigerant to enter the set evaporator 22. When a larger flow rate of refrigerant is required to enter the set evaporator 22 for refrigeration, both the first branch N1 and the second branch N2 can be opened simultaneously, thereby adapting to the variability of different refrigeration conditions.

[0064] It should be noted that the flow ranges of the throttling elements on the first branch N1 and the second branch N2 can be set to the same amount or different amounts. Different types of throttling elements can be selected according to actual needs, and no specific restrictions are made here.

[0065] Alternatively, as Figure 2 As shown, the low temperature section refrigeration cycle system 20 further includes an expansion tank 24;

[0066] The inlet of the expansion tank 24 is connected to the first inlet a of the evaporative condenser 30 , and the outlet of the expansion tank 24 is connected to the inlet of the low-temperature stage compressor 21 .

[0067] Specifically, the inlet of the expansion tank 24 is connected to the first inlet a of the evaporative condenser 30 via a solenoid valve m. Due to the physical properties of the refrigerant R473A in the low-temperature refrigeration cycle system 20, R473A is a high-pressure gas at room temperature and occupies a larger volume than other refrigerants. To ensure that the system does not trigger a high-pressure alarm at room temperature, an expansion tank 24 is added to the refrigeration system. This allows the same amount of R473A to expand within a larger space, thereby reducing the pressure.

[0068] At the same time, when the low-temperature refrigeration cycle system 20 is just started, there is a risk of R473A overpressure. In this case, the expansion tank 24 also has a pressure relief function. The refrigerant released into the expansion tank 24 will enter the low-temperature compressor 21 after passing through the capillary throttling and re-enter the refrigeration cycle.

[0069] Alternatively, as Figure 2 As shown, the low-temperature refrigeration cycle system 20 further includes a first hot bypass loop H1 and a first cold bypass loop L1;

[0070] One end of the first thermal bypass loop H1 is connected to the first inlet a of the evaporative condenser 30 , and the other end of the first thermal bypass loop H1 is connected to the inlet of the low-temperature stage compressor 21 ;

[0071] The first thermal bypass circuit H1 is provided with a solenoid valve m and an energy regulating device p in sequence;

[0072] One end of the first cold bypass loop L1 is connected to the first outlet b of the evaporative condenser 30 , and the other end of the first cold bypass loop L1 is connected to the inlet of the low-temperature stage compressor 21 ;

[0073] The first cold bypass circuit L1 is provided with a solenoid valve m and an expansion valve n in sequence.

[0074] Specifically, the first hot bypass loop H1 and the first cold bypass loop L1 are added to control the suction and exhaust state of the low-temperature stage compressor 21. The controller of the refrigeration system will monitor the suction and exhaust state of the low-temperature stage compressor 21 in real time, and open the first hot bypass loop H1 solenoid valve m and adjust the energy regulating device p as needed, or open the solenoid valve m and expansion valve n on the first cold bypass loop L1.

[0075] The addition of the first cold bypass loop L1 is to reduce the compressor exhaust temperature, prevent the lubricating oil from deteriorating due to high temperature, and control the system exhaust temperature. When the low-temperature compressor 21 is in normal use, the compression ratio should be maintained in the range of 5 to 13. Too high or too low will affect the operation of the low-temperature compressor 21. The first cold bypass loop L1 is to draw a low-temperature refrigerant from the liquid outlet pipe of the evaporative condenser 30 (i.e., the first outlet b mentioned above) to merge into the return air when the compression ratio of the low-temperature compressor 21 is too high, thereby reducing the return air pressure and thus the compression ratio.

[0076] The function of the first thermal bypass loop H1 is to draw a high-temperature and high-pressure gas-liquid two-phase refrigerant from the outlet of the pre-cooling condenser 23 when the return air superheat of the low-temperature stage compressor 21 is low, pass through the solenoid valve m and the energy regulation device p, and merge into the return air to increase the return air temperature, thereby increasing the return air superheat and preventing liquid hammer in the low-temperature stage compressor 21.

[0077] Optionally, the high temperature section refrigeration cycle system 10 further includes a second hot bypass loop H2 and a second cold bypass loop L2;

[0078] One end of the second thermal bypass loop H2 is connected to the inlet of the condenser 12, and the other end of the second thermal bypass loop H2 is connected to the inlet of the high-temperature stage compressor 11;

[0079] The second thermal bypass circuit H2 is provided with a solenoid valve m and an energy regulating device p in sequence;

[0080] One end of the second cold bypass loop L2 is connected to the outlet of the condenser 12, and the other end of the second cold bypass loop L2 is connected to the inlet of the high-temperature stage compressor 11;

[0081] The second cold bypass circuit L2 is provided with a solenoid valve m and an expansion valve n in sequence.

[0082] Specifically, the functions of the second hot bypass loop H2 and the second cold bypass loop L2 in the high-temperature refrigeration cycle system 10 are similar to those of the first hot bypass loop H1 and the first cold bypass loop L1 in the low-temperature refrigeration cycle system 20 and are not described in detail here.

[0083] It should be noted that in order to ensure that the exhaust temperature of the low-temperature compressor 21 does not exceed the standard under different refrigeration conditions, an additional cold bypass circuit can be set in the low-temperature section refrigeration cycle system 20, that is, two first cold bypass circuits L1 are set to ensure that the exhaust temperature of the low-temperature compressor 21 meets the standard.

[0084] Optionally, the refrigeration system further comprises a pressure controller;

[0085] The pressure controller is electrically connected to the low-temperature stage compressor 21 in the low-temperature stage refrigeration cycle system 20 and the high-temperature stage compressor 11 in the high-temperature stage refrigeration cycle system 10;

[0086] The pressure controller is configured to control the corresponding compressor to stop running or open the pressure relief valve to relieve pressure when it detects that the pressure of the low-temperature compressor 21 or the high-temperature compressor 11 exceeds the standard.

[0087] Specifically, in order to protect the normal operation of each compressor in the refrigeration system, a pressure controller can also be added to the refrigeration system to monitor the high-pressure end and low-pressure end of the low-temperature stage compressor 21 in real time, as well as the high-pressure end and low-pressure end of the high-temperature stage compressor 11. When the pressure exceeds the standard value, the pressure controller will stop the corresponding compressor or open the pressure relief valve to protect the refrigeration system.

[0088] An embodiment of the present invention further provides an environmental test chamber, which includes the refrigeration system in any of the above embodiments.

[0089] The environmental test chamber provided in the embodiment of the present invention includes the refrigeration system in the above embodiment. Therefore, the environmental test chamber provided in the embodiment of the present invention also has the beneficial effects described in the above embodiment, which will not be described in detail here.

[0090] In the description of the embodiments of the present invention, 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 specific circumstances.

[0091] Finally, it should be noted that the above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the scope of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A refrigeration system, characterized in that: The refrigeration system includes a high-temperature refrigeration cycle system, a low-temperature refrigeration cycle system and an evaporative condenser; The high-temperature section refrigeration cycle system and the low-temperature section refrigeration cycle system are connected via the evaporative condenser; The high-temperature section refrigeration cycle system uses R448A as a refrigerant to perform a refrigeration cycle, and the low-temperature section refrigeration cycle system uses R473A as a refrigerant to perform a refrigeration cycle.

2. The refrigeration system according to claim 1, characterized in that The low-temperature refrigeration cycle system includes a low-temperature compressor and a set evaporator; The outlet of the low-temperature stage compressor is connected to the first inlet of the evaporative condenser; the first outlet of the evaporative condenser is connected to the inlet of the set evaporator through a set pipeline; the outlet of the set evaporator is connected to the inlet of the low-temperature stage compressor; The heat exchange area of the set evaporator is greater than the set area value.

3. The refrigeration system according to claim 2, characterized in that The low-temperature section refrigeration cycle system further includes a pre-cooling condenser, which is arranged between the outlet of the low-temperature stage compressor and the first inlet of the evaporative condenser.

4. The refrigeration system according to claim 1 or 2, characterized in that: The high-temperature section refrigeration cycle system includes a high-temperature compressor, a condenser and a high-temperature evaporator; The high-temperature evaporator is connected in parallel with the evaporative condenser; The outlet of the high-temperature compressor is connected to the inlet of the condenser; the outlet of the condenser is respectively connected to the inlet of the high-temperature evaporator and the second inlet of the evaporative condenser; the outlet of the high-temperature evaporator and the second outlet of the evaporative condenser are both connected to the inlet of the high-temperature compressor.

5. The refrigeration system according to claim 2, characterized in that The setting pipeline includes at least a first branch and a second branch; The first outlet of the evaporative condenser is connected to the first inlet and the second inlet of the set evaporator through the first branch and the second branch respectively.

6. The refrigeration system according to claim 2, characterized in that The low-temperature section refrigeration cycle system further includes an expansion tank; The inlet of the expansion tank is connected to the first inlet of the evaporative condenser, and the outlet of the expansion tank is connected to the inlet of the low-temperature stage compressor.

7. The refrigeration system according to claim 2, characterized in that The low temperature section refrigeration cycle system further includes a first hot bypass circuit and a first cold bypass circuit; One end of the first thermal bypass loop is connected to the first inlet of the evaporative condenser, and the other end of the first thermal bypass loop is connected to the inlet of the low-temperature stage compressor; The first thermal bypass circuit is provided with a solenoid valve and an energy regulating device in sequence; One end of the first cold bypass loop is connected to the first outlet of the evaporative condenser, and the other end of the first cold bypass loop is connected to the inlet of the low-temperature compressor; The first cold bypass circuit is provided with a solenoid valve and an expansion valve in sequence.

8. The refrigeration system according to claim 4, characterized in that The high temperature section refrigeration cycle system further includes a second hot bypass loop and a second cold bypass loop; One end of the second thermal bypass loop is connected to the inlet of the condenser, and the other end of the second thermal bypass loop is connected to the inlet of the high-temperature stage compressor; The second thermal bypass circuit is provided with a solenoid valve and an energy regulating device in sequence; One end of the second cold bypass loop is connected to the outlet of the condenser, and the other end of the second cold bypass loop is connected to the inlet of the high-temperature stage compressor; The second cold bypass circuit is provided with a solenoid valve and an expansion valve in sequence.

9. The refrigeration system according to claim 1, wherein: The refrigeration system further includes a pressure controller; The pressure controller is electrically connected to the low-temperature stage compressor in the low-temperature section refrigeration cycle system and the high-temperature stage compressor in the high-temperature section refrigeration cycle system; The pressure controller is configured to control the corresponding compressor to stop running or open a pressure relief valve to relieve pressure when it is detected that the pressure of the low-temperature compressor or the high-temperature compressor exceeds a standard.

10. An environmental test chamber, characterized in that: The environmental test chamber includes the refrigeration system according to any one of claims 1 to 9.

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