Two-stage compression refrigeration device
By using a temperature sensor instead of the pressure sensor in the secondary compression and refrigeration device, combined with multi-point temperature detection, the problem of high manufacturing costs is solved, and the effect of cost reduction and stable operation is achieved.
Patent Information
- Application Number
- CN202410002749.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-02
- Publication Date
- 2025-07-11
AI Technical Summary
In the existing secondary compression refrigeration device, in order to maintain stable operation and reasonable COP, three pressure sensors are needed, resulting in high manufacturing costs.
A temperature sensor is used to replace the pressure sensor of medium pressure, and the device operation is controlled by detecting the exhaust temperature of the low-stage compressor and the temperature at other key points. The three temperature sensors are combined to ensure stable and reasonable operation.
The manufacturing cost of the refrigeration device is reduced, while maintaining the stability of the device and a reasonable performance coefficient COP.
Smart Images
Figure CN120292736A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of heat exchange equipment, and more particularly, to a two-stage compression refrigeration device. Background Art
[0002] In some two-stage compression refrigeration devices, in the case of heat and temperature changes in the load medium and the heat source medium, in order to maintain the stable operation of the device and a reasonable COP (Coefficient Of Performance), the operation control is generally performed to keep the ratio of the low-stage compression ratio and the high-stage compression ratio constant.
[0003] Through research by the inventor, it is found that in order to ensure stable operation and a reasonable COP, the operation control method needs to measure at least the low-pressure, medium-pressure, and high-pressure in the two-stage compression refrigeration device. Therefore, three pressure sensors are required, but the cost of the pressure sensors is relatively high. Summary of the Invention
[0004] An object of the present invention is to provide a two-stage compression refrigeration device that can reduce its own manufacturing cost.
[0005] The embodiments of the present invention are implemented as follows:
[0006] In a first aspect, the present invention provides a two-stage compression refrigeration device, including:
[0007] A main circuit, on which an evaporator, a low-stage compressor, an intermediate cooler, a high-stage compressor, a condenser, an economizer, and a main expansion valve are sequentially arranged;
[0008] A branch circuit, which has a first end and a second end. The first end is connected to the main circuit and is located between the condenser and the economizer. The branch circuit passes through the economizer, and the second end is connected to the intermediate cooler;
[0009] A first temperature sensor, which is arranged between the low-stage compressor and the intermediate cooler and is used to detect the exhaust temperature of the low-stage compressor.
[0010] Through the above arrangement, replacing the pressure sensor for detecting the medium pressure with the first temperature sensor can save the manufacturing cost of the two-stage compression refrigeration device.
[0011] In an optional embodiment, the two-stage compression refrigeration device further includes a second temperature sensor and a third temperature sensor. The second temperature sensor is arranged on the main circuit and is located on the side of the intermediate cooler away from the first temperature sensor. The third temperature sensor is arranged on the branch circuit and is located on the side of the intermediate cooler away from the first temperature sensor. The third temperature sensor is used to detect the outlet temperature of the economizer.
[0012] With the above settings, by setting three temperature sensors, the stable operation of the two-stage compression refrigeration device can be ensured and a reasonable COP can be achieved, effectively reducing the cost required for the two-stage compression refrigeration device to a lower level.
[0013] In an alternative embodiment, the second temperature sensor is located between the intermediate cooler and the high-stage compressor.
[0014] With the above settings, it is convenient for the second temperature sensor to detect the temperature at the outlet of the intermediate cooler, improving the accuracy of the m value.
[0015] In an alternative embodiment, the second temperature sensor is closer to the intermediate cooler relative to the high-stage compressor.
[0016] With the above settings, the temperature at the outlet of the intermediate cooler near the high-stage compressor can be measured more accurately.
[0017] In an alternative embodiment, the third temperature sensor is located between the intermediate cooler and the economizer.
[0018] With the above settings, the temperature of the medium-pressure compressed refrigerant coming out of the economizer can be effectively detected.
[0019] In an alternative embodiment, the third temperature sensor is closer to the intermediate cooler relative to the economizer.
[0020] With the above settings, the temperature on the side of the intermediate cooler away from the first temperature sensor in the branch can be accurately measured.
[0021] In an alternative embodiment, the first temperature sensor is closer to the intermediate cooler relative to the low-stage compressor.
[0022] With the above settings, the first temperature sensor can more accurately detect the refrigerant temperature at the intermediate cooler near the low-stage compressor.
[0023] In an alternative embodiment, the two-stage compression refrigeration device further includes an intermediate expansion valve, and the intermediate expansion valve is arranged in the branch and located between the condenser and the economizer.
[0024] With the above settings, the refrigerant after passing through the condenser can be depressurized and cooled by the intermediate expansion valve after entering the branch.
[0025] In an alternative embodiment, the two-stage compression refrigeration device further includes a fourth temperature sensor, and the fourth temperature sensor is arranged on one side of the evaporator close to the main expansion valve.
[0026] With the above settings, the fourth temperature sensor can timely detect the refrigerant temperature on one side of the evaporator close to the main expansion valve.
[0027] In an alternative embodiment, the two-stage compression refrigeration device further includes a fifth temperature sensor disposed on one side of the evaporator near the low-stage compressor.
[0028] With the above arrangement, the fifth temperature sensor is used to detect the temperature on one side of the evaporator near the low-stage compressor.
[0029] The beneficial effects of the embodiments of the present invention are as follows: A two-stage compression refrigeration device provided by the embodiments of the present invention includes a main circuit, a branch circuit, and a first temperature sensor. An evaporator, a low-stage compressor, an intermediate cooler, a high-stage compressor, a condenser, an economizer, and a main expansion valve are sequentially arranged on the main circuit. The branch circuit has a first end and a second end. The first end is connected to the main circuit and is located between the condenser and the economizer. The branch circuit passes through the economizer, and the second end is connected to the intermediate cooler. The first temperature sensor is disposed between the low-stage compressor and the intermediate cooler and is used to detect the exhaust temperature of the low-stage compressor. Temperature and pressure are related to a certain extent. The pressure sensor for detecting the medium pressure can be replaced by the first temperature sensor to control the operation of the device. Since the cost of the temperature sensor is lower than that of the pressure sensor, replacing the pressure sensor for detecting the medium pressure with the first temperature sensor can save the manufacturing cost of the two-stage compression refrigeration device. BRIEF DESCRIPTION OF THE DRAWINGS
[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.
[0031] Figure 1 It is a schematic structural diagram of the two-stage compression refrigeration device provided by the embodiments of the present invention;
[0032] Figure 2 It is a schematic structural diagram of an existing two-stage compression refrigeration device.
[0033] Reference Signs: 1 - Two-stage compression refrigeration device; 100 - Main circuit; 110 - Evaporator; 120 - Low-stage compressor; 130 - Intermediate cooler; 140 - High-stage compressor; 150 - Condenser; 160 - Economizer; 170 - Main expansion valve; 200 - Branch circuit; 210 - First end; 220 - Second end; 230 - Intermediate expansion valve; 300 - First temperature sensor; 400 - Second temperature sensor; 500 - Third temperature sensor; 600 - Fourth temperature sensor; 2 - Pressure sensor. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. The components of the embodiments of the present invention usually described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.
[0035] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.
[0036] It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.
[0037] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation of the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive distinction and cannot be understood as indicating or implying relative importance.
[0038] In addition, terms such as "horizontal" and "vertical" do not mean that the components are required to be absolutely horizontal or hanging, but can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.
[0039] In the description of the present invention, it should also be noted that unless otherwise clearly specified and limited, the terms "set", "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0040] The specific structure of a two-stage compression refrigeration device provided by an embodiment of the present invention and the corresponding technical effects brought thereby will be described in detail below with reference to the patent drawings.
[0041] Please refer to Figure 1 , a two-stage compression refrigeration device 1 provided by an embodiment of the present invention includes a main circuit 100, a branch circuit 200, and a first temperature sensor 300.
[0042] Among them, an evaporator 110, a low-stage compressor 120, an intermediate cooler 130, a high-stage compressor 140, a condenser 150, an economizer 160, and a main expansion valve 170 are sequentially arranged on the main circuit 100. The branch circuit 200 has a first end 210 and a second end 220. The first end 210 is communicated with the main circuit 100 and is located between the condenser 150 and the economizer 160. The branch circuit 200 passes through the economizer 160. That is to say, both the main circuit 100 and the branch circuit 200 pass through the economizer 160. Therefore, the economizer 160 can exchange heat with the refrigerant on the main circuit 100 and the branch circuit 200 passing through itself. The second end 220 is connected to the intermediate cooler 130. The first temperature sensor 300 is arranged between the low-stage compressor 120 and the intermediate cooler 130 for detecting the exhaust temperature of the low-stage compressor 120.
[0043] Among them, the intermediate cooler 130 can mix the refrigerant coming out of the economizer 160 and the refrigerant coming out of the low-stage compressor 120.
[0044] Please refer to Figure 2 , in some existing two-stage compression refrigeration devices 1, in order to maintain the stable operation and reasonable COP of the device, three pressure sensors 2 are provided. Since the pressure sensors 2 are expensive, the cost of the two-stage compression refrigeration device 1 will be increased.
[0045] One of the three pressure sensors 2 is arranged between the low-stage compressor 120 and the evaporator 110 for detecting the low-pressure P in the device e , and another pressure sensor 2 is arranged between the low-stage compressor 120 and the high-stage compressor 140 for detecting the intermediate pressure P after passing through the low-stage compressor 120 m , and the last pressure sensor 2 is arranged on the side of the high-stage compressor 140 away from the condenser 150 for detecting the high-pressure P after passing through the high-stage compressor 140 c , and the stable operation and reasonable COP of the device are achieved by keeping the ratio of the low-stage compression ratio and the high-stage compression ratio consistent. It should be noted that the low-stage compression ratio refers to the intermediate pressure / low-pressure, and the high-stage compression ratio refers to the high-pressure / intermediate pressure. In some existing devices, by ensuring K = intermediate pressure * intermediate pressure / low-pressure * high-pressure, that is
[0046] By ensuring a certain value of K, the operation of the device is stabilized and a reasonable COP is achieved.
[0047] In this embodiment, the first temperature sensor 300 is disposed between the low-stage compressor 120 and the intermediate cooler 130 to detect the exhaust temperature of the low-stage compressor 120. That is to say, the temperature of the intermediate pressure section can be detected by the first temperature sensor 300. It is easy to understand that in the cooling device, temperature and pressure have a certain correlation. The pressure sensor 2 for detecting the intermediate pressure can be replaced by the first temperature sensor 300 to control the operation of the device. It can be understood that since the cost of the temperature sensor is lower than that of the pressure sensor 2, replacing the pressure sensor 2 for detecting the intermediate pressure with the first temperature sensor 300 can save the manufacturing cost of the two-stage compression refrigeration device 1.
[0048] Furthermore, in order to more stably achieve the stable operation of the device and a reasonable COP, in this embodiment, the two-stage compression refrigeration device 1 further includes a second temperature sensor 400 and a third temperature sensor 500. The second temperature sensor 400 is disposed in the main circuit 100 and on the side of the intermediate cooler 130 away from the first temperature sensor. The second temperature sensor 400 is used to detect the outlet temperature of the intermediate cooler 130. The third temperature sensor 500 is disposed in the branch circuit 200 and on the side of the intermediate cooler 130 away from the first temperature sensor. The third temperature sensor 500 is used to detect the outlet temperature of the economizer 160.
[0049] That is to say, the first temperature sensor 300 and the second temperature sensor 400 are disposed on the main circuit 100 and on both sides of the intermediate cooler 130, and the third temperature sensor 500 is located on the branch circuit 200 and on the side of the intermediate cooler 130 away from the first temperature sensor 300.
[0050] It can be understood that the following formula can be derived from the heat balance of the intermediate cooler 130.
[0051] mh9 + h2 - (1 + m)h3 = 0. (1)
[0052] It should be noted that h2 refers to the enthalpy of the intermediate pressure compressed refrigerant coming out of the low-stage compressor 120, h3 refers to the enthalpy of the intermediate pressure compressed refrigerant coming out of the intermediate cooler 130, h9 refers to the enthalpy of the intermediate pressure compressed refrigerant leaving the economizer 160, and m represents the flow rate ratio of the intermediate pressure compressed refrigerant coming out of the economizer 160 and the intermediate pressure compressed refrigerant coming out of the low-stage compressor 120, which is called the injection enthalpy flow rate ratio. From the above formula, it can be obtained that
[0053] It is easy to understand that since it is difficult to find a flowmeter suitable for measuring the mixture of refrigerant and refrigeration oil, due to the similarity between the enthalpy difference and the temperature difference in the superheated gas, the following formula (3) can be derived from the above formula (2), and the inventor has found that by controlling the operation to keep the enthalpy injection flow rate constant, the stable operation of the device and a reasonable COP can be maintained.
[0054] It should be noted that the above first temperature sensor 300 is used to detect the temperature of the medium-pressure compressed refrigerant coming out of the low-stage compressor 120, the second temperature sensor 400 is used to detect the temperature of the medium-pressure compressed refrigerant coming out of the intermediate cooler 130, and the third temperature sensor 500 is used to detect the temperature of the medium-pressure compressed refrigerant coming out of the economizer 160. Then, according to the similarity between the enthalpy difference and the temperature difference in the superheated gas region, the above formula (2) can be approximated to the following formula (3).
[0055]
[0056] Among them, T2 is the temperature measured by the first temperature sensor 300, T3 is the temperature measured by the second temperature sensor 400, and T9 is the temperature measured by the third temperature sensor 500.
[0057] In this embodiment, in order to maintain the stable operation of the device and a reasonable COP, the principle of formula (3) can be used to control the operation in such a way that the enthalpy injection flow ratio m is kept constant. Therefore, by setting three temperature sensors, the stable operation of the two-stage compression refrigeration device 1 and a reasonable COP can be ensured. Compared with the existing two-stage compression refrigeration device 1 with three pressure sensors 2, the two-stage compression refrigeration device 1 provided in this embodiment requires lower costs.
[0058] Please refer to Table 1. Table 1 shows the cycle of the two-stage compression refrigeration device 1 with refrigerant R404A, to compare with some existing ones that control the operation by keeping the ratio K of the low-stage compression ratio to the high-stage compression ratio at 1.43. The device in this embodiment operates under the control of keeping the flow ratio m at 0.336 constant.
[0059]
[0060] Table 1
[0061] As can be seen from Table 1, the COP in this embodiment is roughly the same as the data when the ratio K of the low-stage compression ratio to the high-stage compression ratio is kept at 1.43 in the existing ones. Therefore, by setting three temperature sensors, the stable operation of the two-stage compression refrigeration device 1 and a reasonable COP can be ensured. Compared with the existing two-stage compression refrigeration device 1 with three pressure sensors 2, the two-stage compression refrigeration device 1 provided in this embodiment requires lower costs.
[0062] Optionally, the second temperature sensor 400 is located between the intercooler 130 and the high-stage compressor 140, facilitating the second temperature sensor 400 to detect the temperature at the outlet of the intercooler 130, improving the accuracy of the above m value, and ensuring the stability of the operation of the overall device.
[0063] Optionally, the second temperature sensor 400 is closer to the intercooler 130 than to the high-stage compressor 140. It can be understood that since the second temperature sensor 400 is closer to the intercooler 130 than to the high-stage compressor 140, the temperature at the outlet of the intercooler 130 near the high-stage compressor 140 can be measured more accurately. Therefore, when the device operates through the above formula (3), the stability of the operation of the entire device and a reasonable COP can be achieved.
[0064] In some other embodiments, the second temperature sensor 400 can also be disposed at other positions between the intercooler 130 and the high-stage compressor 140.
[0065] Optionally, the first temperature sensor 300 is closer to the intercooler 130 than to the low-stage compressor 120. Similarly to the above, since the first temperature sensor 300 is closer to the intercooler 130 than to the low-stage compressor 120, the first temperature sensor 300 can more accurately detect the refrigerant temperature at the intercooler 130 near the low-stage compressor 120. Therefore, when the device operates through the above formula (3), the stability of the operation of the entire device and a reasonable COP during operation can be achieved.
[0066] In some other embodiments, the first temperature sensor 300 can also be disposed at other positions between the low-stage compressor 120 and the intercooler 130.
[0067] Optionally, the third temperature sensor 500 is located between the intercooler 130 and the economizer 160. It can be understood that since the third temperature sensor 500 is located between the intercooler 130 and the economizer 160, the temperature of the medium-pressure compressed refrigerant coming out of the economizer 160 can be effectively detected.
[0068] Optionally, the third temperature sensor 500 is closer to the intercooler 130 than to the economizer 160, and the temperature on the side of the intercooler 130 away from the first temperature sensor 300 on the branch 200 can be accurately measured. Of course, in some other alternative embodiments, the third temperature sensor 500 can also be disposed at other positions between the economizer 160 and the intercooler 130.
[0069] Furthermore, in the present embodiment, the two-stage compression refrigeration device 1 further includes an intermediate expansion valve 230. The intermediate expansion valve 230 is disposed in the branch 200 and located between the condenser 150 and the economizer 160. It can be understood that by providing the intermediate expansion valve 230 on the branch 200, the refrigerant after passing through the condenser 150 can be depressurized and cooled by the intermediate expansion valve 230 after entering the branch 200.
[0070] Optionally, the two-stage compression refrigeration device 1 further includes a fourth temperature sensor disposed on the main circuit 100. The fourth temperature sensor 600 is disposed on the side of the evaporator 110 close to the main expansion valve 170. It can be understood that the fourth temperature sensor 600 can timely detect the temperature of the refrigerant on the side of the evaporator 110 close to the main expansion valve.
[0071] Optionally, the two-stage compression refrigeration device 1 further includes a fifth temperature sensor (not shown in the figure) disposed on the main circuit 100. The fifth temperature sensor is disposed on the side of the evaporator 110 close to the low-stage compressor 120. It can be understood that the fifth temperature sensor is used to detect the temperature on the side of the evaporator 110 close to the low-stage compressor 120.
[0072] In summary, a two-stage compression refrigeration device 1 provided by an embodiment of the present invention includes a main circuit 100, a branch 200, and a first temperature sensor 300. An evaporator 110, a low-stage compressor 120, an intermediate cooler 130, a high-stage compressor 140, a condenser 150, an economizer 160, and a main expansion valve 170 are sequentially disposed on the main circuit 100. The branch 200 has a first end 210 and a second end 220. The first end 210 is communicated with the main circuit 100 and located between the condenser 150 and the economizer 160. The branch 200 passes through the economizer 160, and the second end 220 is connected to the intermediate cooler 130. The first temperature sensor 300 is disposed between the low-stage compressor 120 and the intermediate cooler 130 for detecting the exhaust temperature of the low-stage compressor 120. Temperature and pressure are related to a certain extent. The operation of the device can be controlled by replacing the pressure sensor 2 for detecting the medium pressure with the first temperature sensor 300. Since the cost of the temperature sensor is lower than that of the pressure sensor 2, replacing the pressure sensor 2 for detecting the medium pressure with the first temperature sensor 300 can save the manufacturing cost of the two-stage compression refrigeration device 1.
[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A two-stage compression refrigeration device, characterized in that, Comprising: A main circuit (100) on which an evaporator (110), a low-stage compressor (120), an intermediate cooler (130), a high-stage compressor (140), a condenser (150), an economizer (160), and a main expansion valve (170) are sequentially arranged; A branch circuit (200) having a first end (210) and a second end (220), the first end (210) being connected to the main circuit (100) and located between the condenser (150) and the economizer (160), the branch circuit (200) passing through the economizer (160), and the second end (220) being connected to the intermediate cooler (130); A first temperature sensor (300) arranged between the low-stage compressor (120) and the intermediate cooler (130) for detecting the exhaust temperature of the low-stage compressor (120).
2. The two-stage compression refrigeration device according to claim 1, wherein: The two-stage compression refrigeration device further includes a second temperature sensor (400) and a third temperature sensor (500), the second temperature sensor (400) being arranged on the main circuit (100) and on the side of the intermediate cooler (130) away from the first temperature sensor (300), the third temperature sensor (500) being arranged on the branch circuit (200) and on the side of the intermediate cooler (130) away from the first temperature sensor (300), and the third temperature sensor (500) being used for detecting the outlet temperature of the economizer (160).
3. The two-stage compression refrigeration device according to claim 2, wherein: The second temperature sensor (400) is located between the intermediate cooler (130) and the high-stage compressor (140).
4. The two-stage compression refrigeration device according to claim 2, wherein: The second temperature sensor (400) is closer to the intermediate cooler (130) relative to the high-stage compressor (140).
5. The two-stage compression refrigeration device according to claim 2, wherein: The third temperature sensor (500) is located between the intermediate cooler (130) and the economizer (160).
6. The two-stage compression refrigeration device according to claim 2, wherein: The third temperature sensor (500) is closer to the intermediate cooler (130) relative to the economizer (160).
7. The two-stage compression refrigeration device according to claim 1, wherein: The first temperature sensor (300) is closer to the intermediate cooler (130) relative to the low-stage compressor (120).
8. The two-stage compression refrigeration device according to claim 1, wherein: The two-stage compression refrigeration device further includes an intermediate expansion valve (230) arranged on the branch circuit (200) and located between the condenser (150) and the economizer (160).
9. The two-stage compression refrigeration device according to claim 1, wherein: The two-stage compression refrigeration device further includes a fourth temperature sensor (600), and the fourth temperature sensor (600) is disposed on a side of the evaporator (110) close to the main expansion valve (170).
10. The two-stage compression refrigeration device according to claim 1, wherein: The two-stage compression refrigeration device further includes a fifth temperature sensor, and the fifth temperature sensor is disposed on a side of the evaporator (110) close to the low-stage compressor (120).