Refrigerating system and control method thereof
The refrigeration system of the refrigeration dual-cold storage is refrigerated through a condensing unit, and the load of the condensing unit is controlled according to the operating status of the heat exchanger, which solves the problems of high initial investment and low operating energy efficiency in the existing technology, and achieves the effect of saving initial investment and improving operating efficiency.
Patent Information
- Application Number
- CN202311853619.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-28
- Publication Date
- 2025-07-01
AI Technical Summary
Among the existing refrigeration solutions for refrigeration and refrigeration dual-cold storage, the first solution requires two condenser units, which has high initial investment cost; although the second solution only requires one condenser unit, due to the existence of the evaporation pressure regulating valve, the condenser unit has low operating energy efficiency and high operating costs, and lacks technical solutions that save both initial investment and energy efficiency.
The first and second heat exchangers are refrigerated by a condensing unit, and the load of the condensing unit is controlled according to the remaining operating time of the heat exchanger in operation and the waiting time of the unrunning heat exchanger to improve operation efficiency.
It has achieved initial investment savings, while improving the operating efficiency of the condensation unit and reducing operating costs.
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Figure CN120232198A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field of air conditioning equipment, and particularly to a refrigeration system and its control method. Background Art
[0002] With the increasing requirements of people for food safety and food quality, food storage in restaurants has become an important issue. The cold storage in restaurants is generally divided into two cold storages, namely a freezer and a chiller. The freezer is used to store meat products, and the chiller is used to store foods such as fruits and vegetables.
[0003] For the two cold storages, there are generally two existing refrigeration solutions. First, two sets of refrigeration systems (i.e., two condensing units) are used to refrigerate the freezer and the chiller respectively. Second, one set of refrigeration system (i.e., one condensing unit) is used to refrigerate the freezer and the chiller simultaneously. Among them, an evaporation pressure regulating valve (for example, a back pressure valve) is installed at the outlet of the air cooler of the chiller to regulate the pressure.
[0004] It should be noted that the above introduction to the technical background is only for the convenience of clearly and completely explaining the technical solution of the present invention and facilitating the understanding of those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art just because these solutions are described in the background art part of the present invention. Summary of the Invention
[0005] The inventors of this application have found that both of the above two refrigeration solutions have certain disadvantages. For the first refrigeration solution, its disadvantage is that two condensing units are required, and the initial investment cost is relatively large. For the second refrigeration solution, although only one condensing unit is needed, due to the evaporation pressure regulating valve, the operating energy efficiency of the condensing unit is low and the operating cost is high. Therefore, for the application scenario of a dual cold storage for freezing and refrigeration (for example, a restaurant), there is currently a lack of a technical solution that can save both the initial investment and the energy efficiency.
[0006] This application provides a refrigeration system and its control method. Among them, a condensing unit is used to refrigerate a first heat exchanger and a second heat exchanger. Thus, the initial investment can be saved. In addition, according to the remaining operating duration of the operating heat exchanger and the waiting duration until the next operation of the non-operating heat exchanger, the load of the condensing unit is controlled, thereby improving the operating efficiency of the condensing unit.
[0007] According to the first aspect of the embodiments of this application, a refrigeration system is provided. The refrigeration system includes: a condensing unit, a first heat exchanger, and a second heat exchanger. The condensing unit outputs refrigerant to at least one of the first heat exchanger and the second heat exchanger, and receives the refrigerant flowing out from at least one of the first heat exchanger and the second heat exchanger. Among them, the refrigeration system further includes:
[0008] A control unit that, when the first heat exchanger or the second heat exchanger is operating, controls the load of the condensing unit according to the remaining operating duration of the operating heat exchanger and the waiting duration until the next operation of the non-operating heat exchanger.
[0009] According to a second aspect of the embodiments of the present application, wherein the refrigeration system further includes:
[0010] A first throttle valve connected between the refrigerant outlet of the condensing unit and the refrigerant inlet of the first heat exchanger;
[0011] A second throttle valve connected between the refrigerant outlet of the condensing unit and the refrigerant inlet of the second heat exchanger; and
[0012] A return gas pipeline through which refrigerant flowing out from at least one of the first heat exchanger and the second heat exchanger flows into the condensing unit,
[0013] The return gas pipeline has:
[0014] A pressure regulating valve and a bypass valve connected in parallel between the refrigerant flow outlet of the first heat exchanger and the refrigerant flow inlet of the condensing unit.
[0015] According to a third aspect of the embodiments of the present application, wherein the pressure regulating valve is a back pressure valve.
[0016] According to a fourth aspect of the embodiments of the present application, wherein the pressure regulating valve is an ejector, the return gas pipeline further has a first valve, a first inlet of the ejector is connected to the refrigerant flow outlet of the first heat exchanger, a second inlet of the ejector is connected to the refrigerant flow outlet of the second heat exchanger, an outlet of the ejector is connected to the refrigerant flow inlet of the condensing unit, and the first valve is connected between the second inlet and the outlet of the ejector.
[0017] According to a fifth aspect of the embodiments of the present application, wherein the operating modes of the refrigeration system include at least one of a first mode, a second mode, and a third mode,
[0018] In the first mode, the first throttle valve is open, the second throttle valve is closed, and the bypass valve is open;
[0019] In the second mode, the second throttle valve is open, the first throttle valve is closed, and the bypass valve is closed;
[0020] In the third mode, the first throttle valve is open, the second throttle valve is open, and the bypass valve is closed.
[0021] According to the sixth aspect of the embodiments of the present application, wherein the operating modes of the refrigeration system include at least one of a first mode, a second mode, and a third mode.
[0022] In the first mode, the first throttle valve is opened, the second throttle valve is closed, the bypass valve is opened, and the first valve is closed.
[0023] In the second mode, the second throttle valve is opened, the first throttle valve is closed, the bypass valve is closed, and the first valve is opened.
[0024] In the third mode, the first throttle valve is opened, the second throttle valve is opened, the bypass valve is closed, and the first valve is closed.
[0025] According to the seventh aspect of the embodiments of the present application, wherein when the temperature of the space where the operating heat exchanger is located reaches a first temperature and the temperature of the space where the non-operating heat exchanger is located reaches a second temperature, the control unit stops the operating heat exchanger and starts the non-operating heat exchanger; or
[0026] When the temperature of the space where the operating heat exchanger is located does not reach the first temperature and the temperature of the space where the non-operating heat exchanger is located reaches the second temperature, the control unit keeps the operating heat exchanger running and starts the non-operating heat exchanger.
[0027] According to the eighth aspect of the embodiments of the present application, wherein the control unit calculates the remaining operating duration of the operating heat exchanger as a first time based on the temperature change rate of the space where the operating heat exchanger is located, and calculates the waiting duration until the next operation of the non-operating heat exchanger as a second time based on the temperature change rate of the space where the non-operating heat exchanger is located.
[0028] The control unit controls the load of the condensing unit according to the difference between the first time and the second time.
[0029] According to the ninth aspect of the embodiments of the present application, wherein when the difference between the first time and the second time is greater than a first threshold, the control unit increases the load of the condensing unit.
[0030] According to the tenth aspect of the embodiments of the present application, wherein when the difference between the first time and the second time is less than a second threshold, the control unit decreases the load of the condensing unit.
[0031] According to the eleventh aspect of the embodiments of the present application, wherein when the difference between the first time and the second time is less than the first threshold and greater than the second threshold, the control unit maintains the load of the condensing unit.
[0032] According to the twelfth aspect of the embodiments of the present application, the condensing unit is a unit with adjustable refrigeration capacity.
[0033] According to the thirteenth aspect of the embodiments of the present application, a control method is provided for controlling the above refrigeration system. The refrigeration system includes: a condensing unit, a first heat exchanger, and a second heat exchanger. The condensing unit outputs refrigerant to at least one of the first heat exchanger and the second heat exchanger, and receives refrigerant flowing out from at least one of the first heat exchanger and the second heat exchanger.
[0034] Wherein, the control method includes:
[0035] When the first heat exchanger or the second heat exchanger is operating, control the load of the condensing unit according to the remaining operating duration of the operating heat exchanger and the waiting duration until the next operation of the non-operating heat exchanger.
[0036] According to the fourteenth aspect of the embodiments of the present application, when the temperature of the space where the operating heat exchanger is located reaches a first temperature and the temperature of the space where the non-operating heat exchanger is located reaches a second temperature, stop the operating heat exchanger and start the non-operating heat exchanger; or
[0037] When the temperature of the space where the operating heat exchanger is located does not reach the first temperature and the temperature of the space where the non-operating heat exchanger is located reaches the second temperature, keep the operating heat exchanger running and start the non-operating heat exchanger.
[0038] According to the fifteenth aspect of the embodiments of the present application, calculate the remaining operating duration of the operating heat exchanger as a first time according to the temperature change rate of the space where the operating heat exchanger is located, and calculate the waiting duration until the next operation of the non-operating heat exchanger as a second time according to the temperature change rate of the space where the non-operating heat exchanger is located.
[0039] Control the load of the condensing unit according to the difference between the first time and the second time.
[0040] According to the sixteenth aspect of the embodiments of the present application, when the difference between the first time and the second time is greater than a first threshold, increase the load of the condensing unit.
[0041] According to the seventeenth aspect of the embodiments of the present application, when the difference between the first time and the second time is less than a second threshold, reduce the load of the condensing unit.
[0042] According to the eighteenth aspect of the embodiments of the present application, when the difference between the first time and the second time is less than the first threshold and greater than the second threshold, the load of the condensing unit is maintained.
[0043] The beneficial effects of the present application are as follows: By using one condensing unit to cool the first heat exchanger and the second heat exchanger, the initial investment can be saved. In addition, according to the remaining operating duration of the operating heat exchanger and the waiting duration until the next operation of the non-operating heat exchanger, the load of the condensing unit is controlled, thereby improving the operating efficiency of the condensing unit.
[0044] Referring to the following description and the accompanying drawings, specific embodiments of the present application are disclosed in detail, indicating the ways in which the principles of the present application can be adopted. It should be understood that the embodiments of the present application are not limited in scope thereby. Within the spirit and terms of the appended claims, the embodiments of the present application include many changes, modifications, and equivalents. Description of the Drawings
[0045] The accompanying drawings included are used to provide a further understanding of the embodiments of the present application, which form a part of the specification, are used to illustrate the embodiments of the present application, and together with the written description, explain the principles of the present application. Obviously, the drawings in the following description are only some embodiments of the present application, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts. In the drawings:
[0046] Figure 1 is a schematic diagram of the refrigeration system of this embodiment;
[0047] Figure 2 is another schematic diagram of the refrigeration system of this embodiment;
[0048] Figure 3 is another schematic diagram of the refrigeration system of this embodiment;
[0049] Figure 4 is a flowchart of the control unit of this embodiment controlling the load of the condensing unit;
[0050] Figure 5 is a schematic diagram of the temperature change of the first space and the second space of this embodiment;
[0051] Figure 6 is another schematic diagram of the temperature change of the first space and the second space of this embodiment;
[0052] Figure 7 is another schematic diagram of the temperature change of the first space and the second space of this embodiment;
[0053] Figure 8It is a schematic diagram of the control method of the refrigeration system in this embodiment;
[0054] Figure 9 It is a schematic diagram of step S20 in this embodiment;
[0055] Figure 10 It is a schematic diagram of step S203 in this embodiment;
[0056] Figure 11 It is another schematic diagram of the control method of the refrigeration system in this embodiment. Detailed implementation manners
[0057] Referring to the accompanying drawings, through the following description, the foregoing and other features of the present application will become apparent. In the description and drawings, specific embodiments of the present application are specifically disclosed, which show some embodiments in which the principles of the present application can be adopted. It should be understood that the present application is not limited to the described embodiments. On the contrary, the present application includes all modifications, variations, and equivalents falling within the scope of the appended claims.
[0058] In the embodiments of the present application, terms such as "first" and "second" are used to distinguish different elements in terms of name, but do not indicate the spatial arrangement or time sequence of these elements, and these elements should not be limited by these terms. The term "and / or" includes any one and all combinations of one or more of the related listed terms. Terms such as "comprising", "including", and "having" mean the presence of the stated features, elements, components, or assemblies, but do not exclude the presence or addition of one or more other features, elements, components, or assemblies. In the description of the present application, unless otherwise specified, the meaning of "a plurality" is two or more.
[0059] In the embodiments of the present application, the singular forms "a", "the", etc. include the plural forms and should be broadly understood as "a kind" or "a class" rather than being limited to the meaning of "one"; in addition, the term "the" should be understood to include both the singular form and the plural form unless the context clearly indicates otherwise. In addition, the term "according to" should be understood as "at least partially according to...", and the term "based on" should be understood as "at least partially based on...", unless the context clearly indicates otherwise.
[0060] In the description of the present application, it should be noted that unless otherwise clearly defined and limited, the terms "installed", "connected", and "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 it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood through specific situations.
[0061] Example 1
[0062] Example 1 of the present application provides a refrigeration system, Figure 1 which is a schematic diagram of the refrigeration system of this example. As Figure 1 shown, the refrigeration system 100 includes: a condensing unit 1, a first heat exchanger 4, and a second heat exchanger 5. The condensing unit 1 outputs refrigerant to at least one of the first heat exchanger 4 and the second heat exchanger 5, and receives the refrigerant flowing out from at least one of the first heat exchanger 4 and the second heat exchanger 5.
[0063] The refrigeration system 100 further includes a control unit 7. When the first heat exchanger 4 or the second heat exchanger 5 is operating, the control unit 7 controls the load of the condensing unit 1 according to the remaining operating duration (ta) of the operating heat exchanger and the waiting duration (tb) of the non-operating heat exchanger until the next operation.
[0064] According to the refrigeration system 100 of this example, the first heat exchanger 4 and the second heat exchanger 5 are refrigerated by one condensing unit 1, thereby saving the initial investment; in addition, according to the remaining operating duration of the operating heat exchanger and the waiting duration of the non-operating heat exchanger until the next operation, the load of the condensing unit 1 is controlled, thereby improving the operating efficiency of the condensing unit 1.
[0065] In some embodiments, the condensing unit 1 includes a condenser and a compressor. The condensing unit 1 is a unit with adjustable refrigeration capacity. For example, the compressor of the condensing unit 1 can be a variable frequency compressor, a digital compressor, or a parallel compressor, etc. The compressor is used to discharge the high-temperature and high-pressure refrigerant and to recover the recycled refrigerant. The high-temperature and high-pressure refrigerant discharged by the compressor is dissipated by heat through the condenser, and the temperature gradually decreases and is slowly cooled into a normal-temperature and high-pressure refrigerant. The condensing unit 1 may further include a capillary tube. The normal-temperature and high-pressure refrigerant flowing out from the condenser becomes a normal-temperature and low-pressure refrigerant through the capillary tube. The refrigerant flowing out from the capillary tube absorbs heat in the evaporator, so that the temperature around the absorber decreases. The refrigerant flowing out from the evaporator returns to the compressor again to complete a cycle.
[0066] The first heat exchanger 4 and the second heat exchanger 5 may have an evaporator. In addition, the first heat exchanger 4 and the second heat exchanger 5 may have a fan, thereby improving the heat exchange efficiency.
[0067] In some embodiments, the first heat exchanger 4 is disposed in the first space, and the second heat exchanger 5 is disposed in the second space. When the first heat exchanger 4 is operating, it controls or adjusts the temperature of the first space, and when the second heat exchanger 5 is operating, it controls or adjusts the temperature of the second space. For example, when the first heat exchanger 4 is operating, the temperature of the first space reaches a first preset temperature; when the second heat exchanger 5 is operating, the temperature of the second space reaches a second preset temperature. The first preset temperature may be higher than the second preset temperature.
[0068] The first space and the second space can be two different cold storage rooms. For example, the first space can be a cold storage room, and the second space can be a freezer room. The first space and the second space can also be two different rooms, and so on. The present application does not limit this, as long as the first space and the second space are two different spaces with different temperature requirements.
[0069] In some embodiments, as Figure 1 shown, the refrigeration system 100 further includes a first throttle valve 2, a second throttle valve 3, and a return gas pipeline 6.
[0070] The first throttle valve 2 is connected between the refrigerant outlet 11 of the condensing unit 1 and the refrigerant inlet 41 of the first heat exchanger 4.
[0071] The second throttle valve 3 is connected between the refrigerant outlet 11 of the condensing unit 1 and the refrigerant inlet 51 of the second heat exchanger 5.
[0072] The refrigerant flowing out from at least one of the first heat exchanger 4 and the second heat exchanger 5 flows into the condensing unit 1 through the return gas pipeline 6.
[0073] The return gas pipeline 6 has a pressure regulating valve ( Figure 1 not shown) and a bypass valve ( Figure 1 not shown) connected in parallel between the refrigerant flow outlet 42 of the first heat exchanger 4 and the refrigerant flow inlet 12 of the condensing unit 1. Among them, the pressure regulating valve is used to regulate the pressure of the refrigerant. For example, it can reduce the pressure of the refrigerant.
[0074] Figure 2 is another schematic diagram of the refrigeration system 100 of this embodiment. It shows a specific structure of the return gas pipeline 6.
[0075] As Figure 2 shown in the embodiment, the pressure regulating valve is a back pressure valve 62, and the bypass valve is a bypass valve 61. Among them, the bypass valve 61 can be an electromagnetic valve or other types of valves.
[0076] Figure 3 is another schematic diagram of the refrigeration system 100 of this embodiment. It shows another specific structure of the return gas pipeline 6.
[0077] As Figure 3In the illustrated embodiment, the pressure regulating valve of the suction line 6 is an ejector 22, and the bypass valve is a bypass valve 21. The suction line 6 also has a first valve 23. Among them, the first inlet 221 of the ejector 22 is connected to the refrigerant flow outlet 42 of the first heat exchanger 4, the second inlet 222 of the ejector 22 is connected to the refrigerant flow outlet 52 of the second heat exchanger 5, the outlet of the ejector 22 is connected to the refrigerant flow inlet of the condensing unit 1, and the first valve 23 is connected between the second inlet 222 and the outlet 223 of the ejector.
[0078] For example, both the bypass valve 21 and the first valve 23 are solenoid valves. That is, the bypass valve 21 is a refrigerated solenoid valve, and the first valve 23 is a frozen solenoid valve. In addition, the bypass valve 21 and the first valve 23 can also be other types of valves.
[0079] In some embodiments, the operating modes of the refrigeration system 100 include at least one of a first mode, a second mode, and a third mode. Among them, in the first mode, the first heat exchanger 4 operates, and the second heat exchanger 5 does not operate; in the second mode, the first heat exchanger 4 does not operate, and the second heat exchanger 5 operates; in the third mode, the first heat exchanger 4 operates, and the second heat exchanger 5 also operates. For example, the first mode is a refrigerated mode, the second mode is a frozen mode, and the third mode is a dual-temperature mode.
[0080] The control unit 7 can control the opening and closing states of each valve according to the operating mode of the refrigeration system 100.
[0081] Among them, for Figure 2 the illustrated refrigeration system 100, the control unit 7 can control such that: in the first mode, the first throttle valve 2 is opened, the second throttle valve 3 is closed, and the bypass valve 61 is opened; in the second mode, the second throttle valve 3 is opened, the first throttle valve 2 is closed, and the bypass valve 61 is closed; in the third mode, the first throttle valve 2 is opened, the second throttle valve 3 is opened, and the bypass valve 61 is closed.
[0082] For example, in the first mode, the first throttle valve 2 is opened, the second throttle valve 3 is closed, and the liquid refrigerant of the condensing unit 1 enters the first heat exchanger 4 through the throttling of the first throttle valve 2 for evaporation refrigeration. After complete evaporation, the gaseous refrigerant returns to the condensing unit 1 through the suction line 6.
[0083] For another example, in the second mode, the second throttle valve 3 is opened, the first throttle valve 2 is closed, and the liquid refrigerant of the condensing unit 1 enters the second heat exchanger 5 through the throttling of the second throttle valve 3 for evaporation refrigeration. After complete evaporation, the gaseous refrigerant returns to the condensing unit 1 through the suction line 6.
[0084] For another example, in the third mode, the first throttle valve 2 is opened, the second throttle valve 3 is opened, the liquid refrigerant of the condensing unit 1 enters the first heat exchanger 4 after throttling through the first throttle valve 2 for evaporation refrigeration. At the same time, the liquid refrigerant of the condensing unit 1 enters the second heat exchanger 5 after throttling through the second throttle valve 3 for evaporation refrigeration. The gaseous refrigerant that is completely evaporated in the first heat exchanger 4 enters the return air pipeline 6 to reduce pressure and then is mixed with the gaseous refrigerant that is completely evaporated in the second heat exchanger 5 and returns to the condensing unit 1 together.
[0085] For Figure 3 For the refrigeration system 100 shown, the control unit 7 can be controlled such that: in the first mode, the first throttle valve 2 is opened, the second throttle valve 3 is closed, the bypass valve 21 is opened, and the first valve 23 is closed; in the second mode, the second throttle valve 3 is opened, the first throttle valve 2 is closed, the bypass valve 21 is closed, and the first valve 23 is opened; in the third mode, the first throttle valve 2 is closed, the second throttle valve 3 is closed, the bypass valve 21 is closed, and the first valve 23 is closed.
[0086] In the present application, due to the presence of a bypass valve (for example, Figure 2 the bypass valve 61 or Figure 3 the bypass valve 21), in the first mode, the refrigerant can flow back to the condensing unit 1 through the bypass valve 61 or 21 without having to flow through the pressure regulating valve 62 or 22. Therefore, the operating efficiency of the refrigeration system 100 is relatively high; in addition, in the second mode, the refrigerant also does not flow through the pressure regulating valve 62 or 22 through the first heat exchanger 4. Therefore, the operating efficiency of the refrigeration system 100 is also relatively high.
[0087] In some embodiments, when the first heat exchanger 4 or the second heat exchanger 5 is operating, the control unit 7 can control the load of the condensing unit according to the remaining operating duration (ta) of the operating heat exchanger and the waiting duration (tb) of the non-operating heat exchanger until the next operation, so that the refrigeration system 100 operates in the first mode or the second mode as much as possible to maintain the high-efficiency operation of the refrigeration system 100.
[0088] The operating heat exchanger can be one of the first heat exchanger 4 and the second heat exchanger 5, and the non-operating heat exchanger can be the other of the first heat exchanger 4 and the second heat exchanger 5. Hereinafter, taking the first heat exchanger 4 being in the operating state and the second heat exchanger 5 being in the shutdown state as an example (that is, the operating heat exchanger is the first heat exchanger 4 and the non-operating heat exchanger is the second heat exchanger 5), an explanation will be given.
[0089] For example, the first heat exchanger 4 is in an operating state until the temperature of the first space where the first heat exchanger 4 is located meets certain conditions, and then the first heat exchanger 4 stops operating. Then, the remaining operating duration (ta) of the operating heat exchanger refers to the period from the current moment until the first heat exchanger 4 stops operating. The second heat exchanger 5 is in a shutdown state until the temperature of the second space where the second heat exchanger 5 is located meets certain conditions and then starts operating. Then, the waiting duration (tb) of the non-operating heat exchanger until the next operation refers to the period from the current moment until the second heat exchanger 5 starts operating. The control unit 7 controls the load of the condensing unit 1 based on the remaining operating duration (ta) of the operating heat exchanger and the waiting duration (tb) of the non-operating heat exchanger until the next operation, that is, controls the load of the compressor of the condensing unit 1.
[0090] In some embodiments, when the temperature of the space where the operating heat exchanger is located reaches the first temperature and the temperature of the space where the non-operating heat exchanger is located reaches the second temperature, the control unit 7 stops the operating heat exchanger and starts the non-operating heat exchanger; or, when the temperature of the space where the operating heat exchanger is located does not reach the first temperature and the temperature of the space where the non-operating heat exchanger is located reaches the second temperature, the control unit 7 keeps the operating heat exchanger running and starts the non-operating heat exchanger.
[0091] For example, the first heat exchanger 4 is in an operating state and the second heat exchanger 5 is in a shutdown state. When the temperature of the space (e.g., the first space) where the first heat exchanger 4 is located reaches the first temperature (e.g., the pre-set shutdown temperature of the first heat exchanger 4, or the first threshold temperature of the first space), and the temperature of the space (e.g., the second space) where the second heat exchanger 5 is located reaches the second temperature (e.g., the pre-set startup temperature of the second heat exchanger 5, or the second threshold temperature of the second space), stop the operating first heat exchanger 4 and start the non-operating second heat exchanger 5. Or, when the temperature of the space (e.g., the first space) where the first heat exchanger 4 is located does not reach the first temperature (e.g., the pre-set shutdown temperature of the first heat exchanger 4, or the first threshold temperature of the first space), and the temperature of the space (e.g., the second space) where the second heat exchanger 5 is located reaches the second temperature (e.g., the pre-set startup temperature of the second heat exchanger 5, or the second threshold temperature of the second space), keep the first heat exchanger 4 running and start the non-operating second heat exchanger 5.
[0092] For another example, the control unit 7 controls the operating state of the first heat exchanger 4 according to the temperature of the first space, and controls the operating state of the second heat exchanger 5 according to the temperature of the second space. Or, the control unit 7 controls or switches the operating mode of the refrigeration system 100 according to the temperatures of the first space and the second space.
[0093] Figure 4 It is a flowchart for the control unit 7 to control the load of the condensing unit 1. Figure 4 It shows how the control unit 7 controls the load of the condensing unit 1 under different modes.
[0094] In some embodiments, as Figure 4 shown, in step 200, the operating mode of the refrigeration system 100 is obtained.
[0095] In some embodiments, as Figure 4 shown, when the refrigeration system 100 is in the third mode (step 202), that is, both the first heat exchanger 4 and the second heat exchanger 5 are in the operating state, the control unit 7 controls the load of the condensing unit 1 to be a preset load (step 204). This preset load can be a relatively high load value. Thus, the condensing unit 1 can exit the third mode and enter the first mode or the second mode as soon as possible, which can avoid the condensing unit 1 being in the inefficient third mode for a long time and improve the operating efficiency of the condensing unit 1.
[0096] In other embodiments, when the refrigeration system 100 is in the first mode or the second mode (step 201), that is, only one of the first heat exchanger 4 and the second heat exchanger 5 is in the operating state, the control unit 7 controls the load of the condensing unit 1 according to the difference between the first time and the second time, so that the refrigeration system 100 works in the first mode or the second mode as much as possible, thereby improving the operating efficiency of the condensing unit 1.
[0097] Specifically, in some embodiments, as Figure 4 shown, when the refrigeration system 100 is in the first mode or the second mode, the control unit 7 calculates the remaining operating duration of the operating heat exchanger as the first time according to the temperature change rate of the space where the operating heat exchanger is located, and calculates the waiting duration for the non-operating heat exchanger to operate next as the second time according to the temperature change rate of the space where the non-operating heat exchanger is located. The control unit 7 controls the load of the condensing unit 1 according to the difference between the first time and the second time.
[0098] For example, the first heat exchanger 4 is in the operating state and the second heat exchanger 5 is in the shutdown state. The remaining operating duration (ta) of the first heat exchanger 4 is used as the first time, and the waiting duration (tb) for the second heat exchanger 5 to operate next is used as the second time. The control unit 7 calculates the first time according to the temperature change rate of the space where the first heat exchanger 4 is located (for example, the first space), and calculates the second time according to the temperature change rate of the space where the second heat exchanger 5 is located (for example, the second space). The control unit 7 controls the load of the compressor of the condensing unit 1 according to the difference between the first time and the second time.
[0099] Specifically, in step 203, the current temperature of the first space and the current temperature of the second space are obtained; in step 205, the control unit 7 calculates the first time ta and the second time tb.
[0100] For example, the control unit 7 calculates the first time ta of the first heat exchanger 4 in the following manner:
[0101] The first time ta of the first heat exchanger 4 is equal to the difference between the current temperature of the first space and the first temperature (for example, the shutdown temperature of the first heat exchanger 4 set in advance, or the first threshold temperature of the first space) divided by the temperature change rate of the first space.
[0102] For another example, the control unit 7 calculates the second time tb of the second heat exchanger 5 in the following manner:
[0103] The second time tb of the second heat exchanger 5 is equal to the difference between the current temperature of the second space and the second temperature (for example, the startup temperature of the second heat exchanger 5 set in advance, or the second threshold temperature of the second space) divided by the temperature change rate of the second space.
[0104] For another example, the control unit 7 can also calculate the first time ta and the second time tb in other ways. For details, reference can be made to the prior art, and the present application places no restrictions thereon.
[0105] In step 207, the control unit 7 compares the difference between the first time and the second time with a threshold value, and controls the load of the condensing unit 1 according to the comparison result. There are three cases for the comparison result of the difference between the first time and the second time and the threshold value.
[0106] For example, in the first case, as Figure 4 shown in 2071, when the difference between the first time ta and the second time tb is greater than the first threshold value R1, the control unit 7 increases the load of the condensing unit 1.
[0107] For example, the first heat exchanger 4 is in an operating state, and the second heat exchanger 5 is in a shutdown state. When the difference between the first time ta of the first heat exchanger 4 and the second time tb of the second heat exchanger 5 is greater than the first threshold value, the load of the compressor of the condensing unit 1 is increased, so that the temperature change rate of the first space where the first heat exchanger 4 is located is accelerated, the first time ta of the first heat exchanger 4 is shortened, and the first heat exchanger 4 reaches the shutdown condition as soon as possible, thereby improving the operating efficiency of the condensing unit 1. The first threshold value can be 1 minute, 2 minutes, etc., and can be set according to requirements.
[0108] For example, in the second case, as Figure 4 shown in 2072, when the difference between the first time ta and the second time tb is less than the second threshold value R2, the control unit 7 reduces the load of the condensing unit 1.
[0109] For example, the first heat exchanger 4 is in an operating state, and the second heat exchanger 5 is in a shutdown state. When the difference between the first time ta of the first heat exchanger 4 and the second time tb of the second heat exchanger 5 is less than the second threshold value, the control unit 7 reduces the load of the compressor of the condensing unit 1, so that the temperature change rate of the second space where the second heat exchanger 5 is located is accelerated, the second time tb of the second heat exchanger 5 is shortened, and the second heat exchanger 5 reaches the startup condition as soon as possible, thereby improving the operating efficiency of the condensing unit 1. The second threshold value can be -1 minute, -2 minutes, etc., and can be set according to requirements. The second threshold value is a value smaller than the first threshold value.
[0110] For example, in the third case, as Figure 4 shown in 2073, when the difference between the first time ta and the second time tb is less than the first threshold value R1 and greater than the second threshold value R2, the control unit 7 maintains the load of the condensing unit 1.
[0111] For example, the first heat exchanger 4 is in an operating state, and the second heat exchanger 5 is in a shutdown state. When the difference between the first time ta of the first heat exchanger 4 and the second time tb of the second heat exchanger 5 is less than the first threshold value and greater than the second threshold value, the control unit 7 maintains the load of the compressor of the condensing unit 1, thereby stabilizing the load of the compressor within a certain range, so that the difference between the first time ta and the second time tb is stabilized within a certain range, thereby improving the operating efficiency of the condensing unit 1.
[0112] The following describes the situation of controlling the load of the condensing unit 1 and mode conversion. T1 and T1 ′ respectively represent the first threshold temperature and the second threshold temperature of the first space, or the shutdown temperature and the startup temperature of the first heat exchanger 4. T2 and T2 ′ respectively represent the first threshold temperature and the second threshold temperature of the second space, or the shutdown temperature and the startup temperature of the second heat exchanger 5.
[0113] Figure 5 is a schematic diagram of the temperature change of the first space and the second space. Figure 5 shows the situation of realizing mode conversion by controlling the load of the condensing unit 1. As Figure 5 shown, the control unit 7 realizes the switching between the first mode and the second mode by controlling the load of the condensing unit 1, that is, the time required for the temperature of the first space to rise from the first threshold temperature T1 to the second threshold temperature T1 ′ is equal to the time required for the temperature of the second space to drop from the second threshold temperature T2 to the second threshold temperature T2 ′ required time, that is Figure 5The AB section in []. That is to say, the time required for the temperature of the first space to reach the startup temperature of the first heat exchanger 4 is equal to the time required for the temperature of the second space to reach the shutdown temperature of the second heat exchanger 5. At moment B, the first heat exchanger 4 starts to operate, and the second heat exchanger 5 stops operating, thereby completing the mode conversion.
[0114] In addition, as Figure 5 shown, the time required for the temperature of the first space to drop from the second threshold temperature T1 ′ to the first threshold temperature T1 is equal to the time required for the temperature of the second space to rise from the second threshold temperature T2 ′ to the second threshold temperature T2, that is Figure 5 the BC section in []. That is to say, the time required for the temperature of the first space to reach the shutdown temperature of the first heat exchanger 4 is equal to the time required for the temperature of the second space to reach the startup temperature of the second heat exchanger 5. At moment C, the first heat exchanger 4 stops operating, and the second heat exchanger 5 starts operating, thereby completing the mode conversion.
[0115] Figure 6 is another schematic diagram of the temperature changes in the first space and the second space. Figure 6 shows a situation where the mode conversion cannot be achieved by controlling the load of the condensing unit 1. As Figure 6 shown, the temperature of the second space rises relatively fast, and the temperature of the first space drops relatively slow. When the temperature of the second space has reached the startup temperature of the second heat exchanger 5 (for example Figure 6 at moment D in []), the temperature of the first space has not reached the shutdown temperature of the first heat exchanger 4 yet. That is to say, the second heat exchanger 5 has already started to operate, but the first heat exchanger 4 has not stopped operating yet. Therefore, at moment D, the refrigeration system 100 switches to the third mode. That is, after moment D, the first heat exchanger 4 and the second heat exchanger 5 operate simultaneously until the temperature of the first space reaches the shutdown temperature of the first heat exchanger 4, and the first heat exchanger 4 stops operating, for example Figure 6 at moment E in []. In the DE section, the temperature of the first space continues to drop, and the temperature of the second space may rise, remain unchanged, or drop. After moment E, the refrigeration system 100 exits the third mode.
[0116] Figure 7 is another schematic diagram of the temperature changes in the first space and the second space. Figure 7 shows another situation where the mode conversion cannot be achieved by controlling the load of the condensing unit 1. As Figure 7 shown, the temperature of the first space rises relatively fast, and the temperature of the second space drops relatively slow. When the temperature of the first space has reached the startup temperature of the first heat exchanger 4 (for example Figure 7At the moment D (in the figure), the temperature of the second space has not reached the shutdown temperature of the second heat exchanger 5. That is to say, the first heat exchanger 4 has started to operate, but the second heat exchanger 5 has not stopped operating yet. Therefore, at the moment D, the refrigeration system 100 switches to the third mode. That is, after the moment D, the first heat exchanger 4 and the second heat exchanger 5 operate simultaneously until the temperature of the second space reaches the shutdown temperature of the second heat exchanger 5, and the second heat exchanger 5 stops operating, for example Figure 7 at the moment E in the figure. In the section DE, the temperature of the second space continues to drop, and the temperature of the first space may rise, remain unchanged, or drop. After the moment E, the refrigeration system 100 exits the third mode.
[0117] According to this embodiment, a single condensing unit 1 is used to refrigerate the first heat exchanger 4 and the second heat exchanger 5. Thus, the initial investment can be saved; in addition, according to the remaining operating duration of the operating heat exchanger and the waiting duration of the non-operating heat exchanger until the next operation, the load of the condensing unit 1 is controlled, thereby improving the operating efficiency of the condensing unit 1.
[0118] Embodiment 2
[0119] Embodiment 2 of the present application provides a control method for a refrigeration system 100, which is used to control the refrigeration system 100 described in Embodiment 1. Figure 8 is a schematic diagram of the control method of the refrigeration system 100.
[0120] As Figure 8 shown, the control method of the refrigeration system 100 includes the following steps:
[0121] S20. When the first heat exchanger 4 or the second heat exchanger 5 is operating, control the load of the condensing unit 1 according to the remaining operating duration of the operating heat exchanger and the waiting duration of the non-operating heat exchanger until the next operation.
[0122] In this embodiment, for the description of the above step S20, reference can be made to the description of the control unit 7 in Embodiment 1, and details will not be repeated in this embodiment.
[0123] According to the control method of this embodiment, a single condensing unit 1 is used to refrigerate the first heat exchanger 4 and the second heat exchanger 5. Thus, the initial investment can be saved; in addition, according to the remaining operating duration of the operating heat exchanger and the waiting duration of the non-operating heat exchanger until the next operation, the load of the condensing unit 1 is controlled, thereby improving the operating efficiency of the condensing unit 1.
[0124] Figure 9 is a schematic diagram of step S20.
[0125] In some embodiments, as Figure 9 shown, step S20 includes the following steps:
[0126] S201. Calculate the remaining operating duration of the heat exchanger in operation as the first time according to the temperature change rate of the space where the heat exchanger in operation is located;
[0127] S202. Calculate the waiting duration until the next operation of the non-operating heat exchanger as the second time according to the temperature change rate of the space where the non-operating heat exchanger is located;
[0128] S203. Control the load of the condensing unit 1 according to the difference between the first time and the second time.
[0129] In this embodiment, for the descriptions of the above steps S201 - S203, reference can be made to the description of the control unit 7 in Embodiment 1, and details will not be repeated in this embodiment.
[0130] Figure 10 It is a schematic diagram of step S203.
[0131] In some embodiments, as Figure 10 shown, step S203 includes the following steps:
[0132] S2031. When the difference between the first time and the second time is greater than the first threshold, increase the load of the condensing unit 1; or, when the difference between the first time and the second time is less than the second threshold, decrease the load of the condensing unit 1; or, when the difference between the first time and the second time is less than the first threshold and greater than the second threshold, maintain the load of the condensing unit 1.
[0133] In this embodiment, for the description of the above step S2031, reference can be made to the description of the control unit 7 in Embodiment 1, and details will not be repeated in this embodiment.
[0134] Figure 11 It is another schematic diagram of the control method of the refrigeration system 100.
[0135] In some embodiments, as Figure 11 shown, the control method of the refrigeration system 100 includes the following steps:
[0136] S30. When the temperature of the space where the heat exchanger in operation is located reaches the first temperature and the temperature of the space where the non-operating heat exchanger is located reaches the second temperature, stop the heat exchanger in operation and start the non-operating heat exchanger; or, when the temperature of the space where the heat exchanger in operation is located does not reach the first temperature and the temperature of the space where the non-operating heat exchanger is located reaches the second temperature, keep the heat exchanger in operation and start the non-operating heat exchanger.
[0137] In this embodiment, for the description of the above step S30, reference can be made to the description of the control unit 7 in Embodiment 1, and details will not be repeated in this embodiment.
[0138] The present application has been described in connection with specific embodiments, but those skilled in the art should understand that these descriptions are exemplary and not a limitation on the scope of protection of the present application. Those skilled in the art can make various variations and modifications to the present application according to the spirit and principle of the present application, and these variations and modifications are also within the scope of the present application.
Claims
1. A refrigeration system, the refrigeration system comprising: A condensing unit, a first heat exchanger, and a second heat exchanger, wherein the condensing unit outputs refrigerant to at least one of the first heat exchanger and the second heat exchanger and receives the refrigerant flowing out from at least one of the first heat exchanger and the second heat exchanger. It is characterized in that the refrigeration system further includes: A control unit that, when the first heat exchanger or the second heat exchanger is operating, controls the load of the condensing unit according to the remaining operating duration of the operating heat exchanger and the waiting duration until the next operation of the non-operating heat exchanger.
2. The refrigeration system according to claim 1, characterized in that: The refrigeration system further includes: A first throttle valve connected between the refrigerant output port of the condensing unit and the refrigerant inlet of the first heat exchanger; A second throttle valve connected between the refrigerant output port of the condensing unit and the refrigerant inlet of the second heat exchanger; and A return gas pipeline, and the refrigerant flowing out from at least one of the first heat exchanger and the second heat exchanger flows into the condensing unit through the return gas pipeline. The return gas pipeline has: A pressure regulating valve and a bypass valve connected in parallel between the refrigerant flow outlet of the first heat exchanger and the refrigerant flow inlet of the condensing unit.
3. The refrigeration system according to claim 2, characterized in that: The pressure regulating valve is a back pressure valve.
4. The refrigeration system according to claim 2, characterized in that: The pressure regulating valve is an ejector, and the return gas pipeline further has a first valve. The first inlet of the ejector is connected to the refrigerant flow outlet of the first heat exchanger, the second inlet of the ejector is connected to the refrigerant flow outlet of the second heat exchanger, the outlet of the ejector is connected to the refrigerant flow inlet of the condensing unit, and the first valve is connected between the second inlet and the outlet of the ejector.
5. The refrigeration system according to claim 3, characterized in that: The operating modes of the refrigeration system include at least one of a first mode, a second mode, and a third mode. In the first mode, the first throttle valve is opened, the second throttle valve is closed, and the bypass valve is opened. In the second mode, the second throttle valve is opened, the first throttle valve is closed, and the bypass valve is closed. In the third mode, the first throttle valve is opened, the second throttle valve is opened, and the bypass valve is closed.
6. The refrigeration system according to claim 4, characterized in that: The operating modes of the refrigeration system include at least one of a first mode, a second mode, and a third mode. In the first mode, the first throttle valve is opened, the second throttle valve is closed, the bypass valve is opened, and the first valve is closed. In the second mode, the second throttle valve is opened, the first throttle valve is closed, the bypass valve is closed, and the first valve is opened. In the third mode, the first throttle valve is opened, the second throttle valve is opened, the bypass valve is closed, and the first valve is closed.
7. The refrigeration system according to claim 1, characterized in that: When the temperature of the space where the operating heat exchanger is located reaches the first temperature and the temperature of the space where the non-operating heat exchanger is located reaches the second temperature, the control unit stops the operating heat exchanger and starts the non-operating heat exchanger; or When the temperature of the space where the operating heat exchanger is located does not reach the first temperature and the temperature of the space where the non-operating heat exchanger is located reaches the second temperature, the control unit keeps the operating heat exchanger running and starts the non-operating heat exchanger.
8. The refrigeration system according to claim 1, wherein the control unit calculates the remaining running duration of the operating heat exchanger as the first time according to the temperature change rate of the space where the operating heat exchanger is located, and calculates the waiting duration until the next operation of the non-operating heat exchanger as the second time according to the temperature change rate of the space where the non-operating heat exchanger is located, and the control unit controls the load of the condensing unit according to the difference between the first time and the second time.
9. The refrigeration system according to claim 8, wherein when the difference between the first time and the second time is greater than the first threshold, the control unit increases the load of the condensing unit.
10. The refrigeration system according to claim 8, wherein when the difference between the first time and the second time is less than the second threshold, the control unit decreases the load of the condensing unit.
11. The refrigeration system according to claim 8, wherein when the difference between the first time and the second time is less than the first threshold and greater than the second threshold, the control unit keeps the load of the condensing unit.
12. The refrigeration system according to claim 1, wherein the condensing unit is a unit with adjustable refrigeration capacity.
13. A control method for a refrigeration system, used to control the refrigeration system according to any one of claims 1-12, the refrigeration system comprising: A condensing unit, a first heat exchanger and a second heat exchanger, the condensing unit outputs refrigerant to at least one of the first heat exchanger and the second heat exchanger, and receives the refrigerant flowing out from at least one of the first heat exchanger and the second heat exchanger, characterized in that the control method comprises: when the first heat exchanger or the second heat exchanger is operating, controlling the load of the condensing unit according to the remaining running duration of the operating heat exchanger and the waiting duration until the next operation of the non-operating heat exchanger.
14. The control method according to claim 13, wherein when the temperature of the space where the operating heat exchanger is located reaches the first temperature and the temperature of the space where the non-operating heat exchanger is located reaches the second temperature, the operating heat exchanger is stopped and the non-operating heat exchanger is started; or when the temperature of the space where the operating heat exchanger is located does not reach the first temperature and the temperature of the space where the non-operating heat exchanger is located reaches the second temperature, the operating heat exchanger is kept running and the non-operating heat exchanger is started.
15. The control method according to claim 13, wherein Calculate the remaining operating duration of the operating heat exchanger as the first time according to the temperature change rate of the space where the operating heat exchanger is located, and calculate the waiting duration until the next operation of the non-operating heat exchanger as the second time according to the temperature change rate of the space where the non-operating heat exchanger is located. Control the load of the condensing unit according to the difference between the first time and the second time.
16. The control method according to claim 15, wherein: When the difference between the first time and the second time is greater than the first threshold, increase the load of the condensing unit.
17. The control method according to claim 15, wherein: When the difference between the first time and the second time is less than the second threshold, reduce the load of the condensing unit.
18. The control method according to claim 15, wherein: When the difference between the first time and the second time is less than the first threshold and greater than the second threshold, maintain the load of the condensing unit.