Double-cold-source refrigerating system and control method

Abstract

The double-cold-source refrigerating system comprises a heat exchange coil pipe, a refrigerating coil pipe, a heat exchange plate, an electronic expansion valve and a compressor, the heat exchange coil pipe makes contact with the refrigerating coil pipe, an inlet of the heat exchange coil pipe is connected with a system output port, an outlet of the heat exchange coil pipe is connected with a heat exchange inlet of the heat exchange plate, and a heat exchange outlet of the heat exchange plate is connected with a system backflow port. An inlet of the refrigerating coil is connected with a refrigerating outlet of the heat exchange plate through an electronic expansion valve, and an outlet of the refrigerating coil is connected with a refrigerating inlet of the heat exchange plate through a compressor. In the working process, a mechanical cooling mode, a pre-cooling mode and a natural cooling mode are achieved, a proper refrigeration mode is selected according to the comparison of the inlet temperature and the return air temperature of a heat exchange medium, a natural cold source can be fully utilized, meanwhile, the heat exchange coil and the refrigeration coil make contact with each other, the two coils can participate in heat exchange at the same time, the efficiency of the whole machine is improved, and energy waste is avoided. And the operation stability and safety of the system are improved. The invention further provides a control method applying the double-cold-source refrigerating system.

Description

Technical Field

[0001] The present invention relates to the field of refrigeration equipment, and in particular to a dual-cold-source refrigeration system. In addition, the present invention also relates to a control method using the dual-cold-source refrigeration system. Background Art

[0002] The dual-cold source refrigeration system is widely used in various technical fields, such as life refrigeration, server refrigeration, etc. It includes two working modes: mechanical refrigeration and natural refrigeration, and has separate heat exchange coils and refrigeration coils. In the mechanical refrigeration mode, the compressor is started, the refrigerant flows in the refrigeration coil, and the return air blows to the refrigeration coil to blow out cold air to achieve refrigeration. In the natural refrigeration mode, the compressor is turned off, the heat exchange medium flows in the heat exchange coil, and the return air blows to the heat exchange coil to blow out cold air to achieve refrigeration.

[0003] In the process of realizing the present invention, the inventors found that the prior art has at least the following problems: the existing system can only switch between two modes and cannot fully utilize natural cooling; further, the heat exchange coil and the refrigeration coil are separately arranged, and the two coils cannot participate in heat exchange at the same time, which wastes the efficiency of the whole machine, causes energy waste, and reduces the stability and safety of the system operation.

[0004] Therefore, how to provide a dual-cold-source refrigeration system that fully utilizes natural cooling and avoids energy waste is a technical problem that technical personnel in this field currently need to solve. Summary of the invention

[0005] The purpose of the present invention is to provide a dual-cold source refrigeration system to solve the technical problem that the prior art cannot fully utilize natural cooling and causes energy waste. Another purpose of the present invention is to provide a control method using the dual-cold source refrigeration system.

[0006] In order to solve the above technical problems, the present invention provides a dual-cold source refrigeration system, including a heat exchange coil, a refrigeration coil, a heat exchange plate, an electronic expansion valve and a compressor, the heat exchange coil and the refrigeration coil are in contact with each other, the inlet of the heat exchange coil is connected to the system output port, the outlet of the heat exchange coil is connected to the heat exchange inlet of the heat exchange plate, the heat exchange outlet of the heat exchange plate is connected to the system reflux port, the inlet of the refrigeration coil is connected to the refrigeration outlet of the heat exchange plate through the electronic expansion valve, and the outlet of the refrigeration coil is connected to the refrigeration inlet of the heat exchange plate through the compressor.

[0007] Preferably, it also includes a control valve group and a controller that are communicatively connected, and the controller controls the conduction state of the control valve group and the start and stop of the compressor according to the heat exchange medium inlet temperature and return air temperature of the heat exchange coil.

[0008] Preferably, the control valve group includes a first control valve, which is respectively connected to the heat exchange outlet of the heat exchange plate and the system return port, and controls the conduction state between the two.

[0009] Preferably, the control valve group includes a second control valve, which is respectively connected to the heat exchange inlet of the heat exchange plate and the system return port, and controls the conduction state between the two.

[0010] Preferably, the control valve group includes a third control valve, and the third control valve is respectively connected to the heat exchange inlet of the heat exchange plate and the inlet and outlet of the heat exchange coil, and controls the flow opening.

[0011] Preferably, the first control valve and the second control valve are two-way valves, and the third control valve is a three-way valve.

[0012] Preferably, the heat exchange coil and the refrigeration coil are integrally formed, the heat exchange coil is located on the windward side, and the refrigeration coil is located on the air supply side.

[0013] The present invention provides a control method for a dual-cold-source refrigeration system, which uses the dual-cold-source refrigeration system as described in any one of the above, and comprises the following steps:

[0014] Obtain the inlet temperature and return air temperature of the heat exchange medium of the heat exchange coil;

[0015] comparing the inlet temperature and the return air temperature;

[0016] If the inlet temperature is lower than the return air temperature, the difference between the two is calculated. If the difference is lower than the preset temperature, the compressor is controlled to start, and the heat exchange medium is controlled to flow through the heat exchange coil and the heat exchange plate. If the difference is higher than the preset temperature, the compressor is controlled to shut down, and the heat exchange medium is controlled to flow through the heat exchange coil but not through the heat exchange plate.

[0017] Preferably, the method comprises the steps of:

[0018] If the inlet temperature is greater than the return air temperature, the compressor is controlled to start, and the heat exchange medium is controlled to flow through the heat exchange plate and not flow through the heat exchange coil.

[0019] Preferably, the method comprises the steps of:

[0020] Obtaining the real-time flow rate of the heat exchange coil;

[0021] If the real-time flow rate is greater than the preset flow rate, the opening of the three-way valve is reduced to a preset value.

[0022] The present invention provides a dual-cold-source refrigeration system, comprising a heat exchange coil, a refrigeration coil, a heat exchange plate, an electronic expansion valve and a compressor. The heat exchange coil and the refrigeration coil are in contact with each other, the inlet of the heat exchange coil is connected to the system output port, the outlet of the heat exchange coil is connected to the heat exchange inlet of the heat exchange plate, the heat exchange outlet of the heat exchange plate is connected to the system reflux port, the inlet of the refrigeration coil is connected to the refrigeration outlet of the heat exchange plate through the electronic expansion valve, and the outlet of the refrigeration coil is connected to the refrigeration inlet of the heat exchange plate through the compressor.

[0023] During the working process, it has mechanical cooling mode, pre-cooling mode and natural cooling mode. According to the comparison between the inlet temperature of the heat exchange medium and the return air temperature, the appropriate cooling mode is selected to make full use of the natural cold source. At the same time, the heat exchange coil and the refrigeration coil are in contact with each other, and the two coils can participate in heat exchange at the same time, which improves the efficiency of the whole machine, avoids energy waste, and improves the stability and safety of system operation.

[0024] The present invention also provides a control method for applying the dual-cold-source refrigeration system. Since the dual-cold-source refrigeration system has the above-mentioned technical effects, the above-mentioned control method should also have the same technical effects, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG1 is a schematic structural diagram of a first embodiment of a dual-cold-source refrigeration system provided by the present invention;

[0026] FIG2 is a schematic structural diagram of a second embodiment of a dual-cold-source refrigeration system provided by the present invention;

[0027] FIG3 is a schematic structural diagram of a third embodiment of a dual-cold-source refrigeration system provided by the present invention.

[0028] Among them, there are heat exchange coil 1, refrigeration coil 2, heat exchange plate 3, electronic expansion valve 4, compressor 5, system output port 6, system reflux port 7, first control valve 8, second control valve 9, and third control valve 10. DETAILED DESCRIPTION

[0029] The core of the present invention is to provide a dual-cold source refrigeration system to solve the technical problem that the prior art cannot fully utilize natural cooling and causes energy waste. Another core of the present invention is to provide a control method using the dual-cold source refrigeration system.

[0030] In order to enable those skilled in the art to better understand the solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0031] Please refer to FIG. 1 , which is a schematic structural diagram of a first embodiment of a dual-cold-source refrigeration system provided by the present invention.

[0032] The specific embodiment of the present invention provides a dual cold source refrigeration system, including a heat exchange coil 1, a refrigeration coil 2, a heat exchange plate 3, an electronic expansion valve 4 and a compressor 5, wherein the heat exchange coil 1 and the refrigeration coil 2 are in contact with each other. The heat exchange coil 1 and the refrigeration coil 2 are both provided with an inlet and an outlet, and the pipelines of the heat exchange coil 1 and the refrigeration coil 2 do not interfere with each other, the heat exchange plate 3 has a heat exchange inlet, a heat exchange outlet, a refrigeration inlet and a refrigeration outlet, the system output port 6 is connected to the inlet of the heat exchange coil 1, the outlet of the heat exchange coil 1 is connected to the heat exchange inlet of the heat exchange plate 3, and the heat exchange outlet of the heat exchange plate 3 is connected to the system return port 7, forming a heat exchange loop, the heat exchange medium flows in this loop, the fan blows air to the heat exchange coil 1, the air exchanges heat with the heat exchange coil 1, and blows out cold air to achieve refrigeration. The heat exchange medium can be various types of flowing media such as water, wherein the natural cold source outputs the heat exchange medium through the system output port 6, and the heat exchange medium flows back to the natural cold source through the system return port 7. The high-temperature heat exchange medium after the heat exchange is completed is cooled in the natural cold source, and a power device can also be set in the natural cold source. The outlet of the compressor 5 is connected to the refrigeration inlet of the heat exchange plate 3, and the refrigeration outlet of the heat exchange plate 3 is connected to the electronic expansion valve 4, and the electronic expansion valve 4 is connected to the inlet of the refrigeration coil 2. The outlet of the refrigeration coil 2 is connected to the inlet of the compressor 5, forming a refrigeration circuit. The refrigerant flows in this circuit, and the fan blows air to the refrigeration coil 2. The air exchanges heat with the refrigeration coil 2, and blows out cold air to achieve refrigeration.

[0033] During the working process, it has mechanical cooling mode, pre-cooling mode and natural cooling mode. According to the comparison between the inlet temperature of the heat exchange medium and the return air temperature, the appropriate cooling mode is selected to make full use of the natural cold source. At the same time, the heat exchange coil 1 and the cooling coil 2 are in contact with each other, and the two coils can participate in heat exchange at the same time, which improves the efficiency of the whole machine, avoids energy waste, and improves the stability and safety of system operation.

[0034] In order to realize automatic switching of various refrigeration modes, a control valve group and a controller with communication connection are also provided, and equipped with a temperature sensor to obtain the inlet temperature and return air temperature of the heat exchange medium. The controller controls the conduction state of the control valve group and the start and stop of the compressor 5 according to the detection results of multiple temperatures.

[0035] In the first embodiment, the control valve group includes a first control valve 8, which is respectively connected to the heat exchange outlet of the heat exchange plate 3 and the system return port 7, and controls the conduction state between the two. Specifically, the system output port 6 is connected to the inlet of the heat exchange coil 1, the outlet of the heat exchange coil 1 is connected to the heat exchange inlet of the heat exchange plate 3, and the heat exchange outlet of the heat exchange plate 3 is connected to the system return port 7 through the first control valve 8, forming a heat exchange loop, and the heat exchange medium flows in this loop, and the fan blows air to the heat exchange coil 1, and the air exchanges heat with the heat exchange coil 1, and blows out cold air to achieve refrigeration. The outlet of the compressor 5 is connected to the refrigeration inlet of the heat exchange plate 3, and the refrigeration outlet of the heat exchange plate 3 is connected to the electronic expansion valve 4, and the electronic expansion valve 4 is connected to the inlet of the refrigeration coil 2, and the outlet of the refrigeration coil 2 is connected to the inlet of the compressor 5, forming a refrigeration loop, and the refrigerant flows in this loop, and the fan blows air to the refrigeration coil 2, and the air exchanges heat with the refrigeration coil 2, and blows out cold air to achieve refrigeration.

[0036] If working in a low temperature environment, under the action of a natural cold source, the inlet temperature of the heat exchange medium is always lower than the return air temperature, and thus the natural cold source can always be involved in the work. In the pre-cooling mode, the compressor 5 is controlled to start, the first control valve 8 is turned on, the heat exchange medium flows through the system output port 6, the heat exchange coil 1, the heat exchange plate 3, the first control valve 8 and the system return port 7 in sequence, and the refrigerant flows through the compressor 5, the heat exchange plate 3, the electronic expansion valve 4 and the refrigeration coil 2 in sequence, wherein the heat exchange medium and the refrigerant perform heat exchange in the heat exchange plate 3 to help complete the morphological change of the refrigerant. At the same time, since the inlet temperature of the heat exchange medium is always lower than the return air temperature, the fan blowing to the heat exchange coil 1 will not affect the refrigeration work. During refrigeration, the heat exchange coil 1 and the refrigeration coil 2 jointly perform heat exchange with the air, and the heat exchange coil 1 can also pre-cool the refrigeration coil 2 to avoid damage to the refrigeration coil 2, and then blow out cold air. In natural cooling mode, the compressor 5 is controlled to be closed, the first control valve 8 is turned on, and the heat exchange medium flows through the system output port 6, the heat exchange coil 1, the heat exchange plate 3, the first control valve 8 and the system return port 7 in sequence. The refrigerant does not flow. Since the heat exchange medium inlet temperature is always lower than the return air temperature, the fan blows to the heat exchange coil 1. During cooling, the heat exchange coil 1 exchanges heat with the air, and then blows out cold air. Simplify the structural design and save costs.

[0037] Please refer to FIG. 2 , which is a schematic structural diagram of a second embodiment of a dual-cold-source refrigeration system provided by the present invention.

[0038] In the second embodiment, the control valve group includes a first control valve 8 and a second control valve 9, wherein the first control valve 8 is connected to the heat exchange outlet of the heat exchange plate 3 and the system return port 7 respectively, and the second control valve 9 is connected to the heat exchange inlet of the heat exchange plate 3 and the system return port 7 respectively, and controls the conduction state between the two. That is, the heat exchange plate 3 is connected in series with the first control valve 8, and the second control valve 9 is connected in parallel with the heat exchange plate 3 and the first control valve 8.

[0039] Specifically, the system output port 6 is connected to the inlet of the heat exchange coil 1, the outlet of the heat exchange coil 1 is connected to the heat exchange inlet of the heat exchange plate 3, the heat exchange outlet of the heat exchange plate 3 is connected to the system return port 7 through the first control valve 8, forming a heat exchange loop, the heat exchange medium flows in this loop, the fan blows air to the heat exchange coil 1, the air exchanges heat with the heat exchange coil 1, and blows out cold air to achieve refrigeration, and at the same time, the outlet of the heat exchange coil 1 is directly connected to the system return port 7 through the second control valve 9. The outlet of the compressor 5 is connected to the refrigeration inlet of the heat exchange plate 3, the refrigeration outlet of the heat exchange plate 3 is connected to the electronic expansion valve 4, the electronic expansion valve 4 is connected to the inlet of the refrigeration coil 2, and the outlet of the refrigeration coil 2 is connected to the inlet of the compressor 5, forming a refrigeration loop, the refrigerant flows in this loop, the fan blows air to the refrigeration coil 2, the air exchanges heat with the refrigeration coil 2, and blows out cold air to achieve refrigeration.

[0040] If working in a low temperature environment, under the action of a natural cold source, the inlet temperature of the heat exchange medium is always lower than the return air temperature, and thus the natural cold source can always be involved in the work. In the pre-cooling mode, the compressor 5 is controlled to start, the first control valve 8 is turned on, and the second control valve 9 is closed. The heat exchange medium flows through the system output port 6, the heat exchange coil 1, the heat exchange plate 3, the first control valve 8 and the system return port 7 in sequence, and the refrigerant flows through the compressor 5, the heat exchange plate 3, the electronic expansion valve 4 and the refrigeration coil 2 in sequence, wherein the heat exchange medium and the refrigerant perform heat exchange in the heat exchange plate 3 to help complete the morphological change of the refrigerant. At the same time, since the inlet temperature of the heat exchange medium is always lower than the return air temperature, the fan blowing to the heat exchange coil 1 will not affect the refrigeration work. During refrigeration, the heat exchange coil 1 and the refrigeration coil 2 jointly perform heat exchange with the air. The heat exchange coil 1 can also pre-cool the refrigeration coil 2 to avoid damage to the refrigeration coil 2, and then blow out cold air. In natural cooling mode, the compressor 5 is controlled to be closed, the first control valve 8 is closed, and the second control valve 9 is turned on. The heat exchange medium flows through the system output port 6, the heat exchange coil 1, the second control valve 9 and the system return port 7 in sequence. The refrigerant does not flow. Since the heat exchange medium inlet temperature is always lower than the return air temperature, the fan blows to the heat exchange coil 1. During cooling, the heat exchange coil 1 exchanges heat with the air, and then blows out cold air. In natural cooling mode, it does not pass through the heat exchange plate 3, and the water resistance is low and there is no pressure drop.

[0041] Please refer to FIG. 3 , which is a schematic structural diagram of a third embodiment of a dual-cold-source refrigeration system provided by the present invention.

[0042] In the third embodiment, the control valve group includes a first control valve 8, a second control valve 9 and a third control valve 10. The first control valve 8 is connected to the heat exchange outlet of the heat exchange plate 3 and the system return port 7 respectively, the second control valve 9 is connected to the heat exchange inlet of the heat exchange plate 3 and the system return port 7 respectively, and the third control valve 10 is connected to the heat exchange inlet of the heat exchange plate 3 and the inlet and outlet of the heat exchange coil 1 respectively, and controls the flow opening. That is, the heat exchange plate 3 is connected in series with the first control valve 8, the second control valve 9 is connected in parallel with the heat exchange plate 3 and the first control valve 8, and a bypass passage capable of short-circuiting the heat exchange coil 1 is set, and connected to the system through the third control valve 10.

[0043] Specifically, the system output port 6 is connected to the inlet of the heat exchange coil 1, the outlet of the heat exchange coil 1 is connected to the first interface of the third control valve 10, the second interface of the third control valve 10 is connected to the heat exchange inlet of the heat exchange plate 3, and the third interface of the third control valve 10 is connected to the system output port 6 through the bypass passage, and the heat exchange outlet of the heat exchange plate 3 is connected to the system return port 7 through the first control valve 8, forming a heat exchange loop, the heat exchange medium flows in this loop, the fan blows air to the heat exchange coil 1, the air and the heat exchange coil 1 are heat exchanged, and cold air is blown out to achieve refrigeration, and the outlet of the heat exchange coil 1 is also directly connected to the system return port 7 through the second control valve 9. The outlet of the compressor 5 is connected to the refrigeration inlet of the heat exchange plate 3, the refrigeration outlet of the heat exchange plate 3 is connected to the electronic expansion valve 4, and the electronic expansion valve 4 is connected to the inlet of the refrigeration coil 2, and the outlet of the refrigeration coil 2 is connected to the inlet of the compressor 5, forming a refrigeration loop, the refrigerant flows in this loop, the fan blows air to the refrigeration coil 2, the air and the refrigeration coil 2 are heat exchanged, and cold air is blown out to achieve refrigeration.

[0044] During the operation, it is necessary to judge the inlet temperature of the heat exchange medium and the return air temperature. If the inlet temperature of the heat exchange medium is higher than the return air temperature, the heat exchange coil 1 is no longer suitable for participating in the refrigeration work and enters the mechanical cooling mode. The first control valve 8 is opened, the second control valve 9 is closed, the first interface and the second interface of the third control valve 10 are isolated, the second interface and the third interface are connected, the compressor 5 is started, and the heat exchange medium flows through the system output port 6, the third control valve 10, the heat exchange plate 3, the first control valve 8 and the system return port 7 in turn, and the refrigerant flows through the compressor 5, the heat exchange plate 3, the electronic expansion valve 4 and the refrigeration coil 2 in turn, wherein the heat exchange medium and the refrigerant perform heat exchange in the heat exchange plate 3 to help complete the morphology change of the refrigerant. During refrigeration, the refrigeration coil 2 performs heat exchange with the air to blow out cold air.

[0045] If the inlet temperature of the heat exchange medium is lower than the return air temperature, the natural cold source can be kept in operation. In the pre-cooling mode, the compressor 5 is controlled to start, the first control valve 8 is turned on, the second control valve 9 is closed, the first interface of the third control valve 10 is connected to the second interface, and the third interface is isolated. The heat exchange medium flows through the system output port 6, the heat exchange coil 1, the heat exchange plate 3, the first control valve 8 and the system return port 7 in sequence, and the refrigerant flows through the compressor 5, the heat exchange plate 3, the electronic expansion valve 4 and the refrigeration coil 2 in sequence, wherein the heat exchange medium and the refrigerant perform heat exchange in the heat exchange plate 3 to help complete the morphological change of the refrigerant. At the same time, since the inlet temperature of the heat exchange medium is always lower than the return air temperature, the fan blowing to the heat exchange coil 1 will not affect the refrigeration work. During refrigeration, the heat exchange coil 1 and the refrigeration coil 2 jointly perform heat exchange with the air. The heat exchange coil 1 can also achieve pre-cooling for the refrigeration coil 2 to avoid damage to the refrigeration coil 2, and then blow out cold air. In natural cooling mode, the compressor 5 is controlled to be closed, the first control valve 8 is closed, the second control valve 9 is turned on, the first interface of the third control valve 10 is connected to the second interface, and the third interface is isolated. The heat exchange medium flows through the system output port 6, the heat exchange coil 1, the second control valve 9 and the system return port 7 in sequence. The refrigerant does not flow. Since the heat exchange medium inlet temperature is always lower than the return air temperature, the fan blows to the heat exchange coil 1. During cooling, the heat exchange coil 1 exchanges heat with the air, and then blows out cold air. In natural cooling mode, it does not pass through the heat exchange plate 3, and the water resistance is low and there is no pressure drop.

[0046] Preferably, the first control valve 8 and the second control valve 9 are two-way valves, and the third control valve 10 is a three-way valve. The load rate of the direct expansion refrigeration system is calculated by the evaporation temperature, the condensation temperature, and the compressor frequency. When the load rate is higher than 80%, it is found that the flow rate of the heat exchange coil 1 is too large and the pressure drop is large. The three-way valve is closed to 70%, the overall water pressure drop is reduced by 20-30%, and the refrigeration capacity of the heat exchange coil 1 is reduced by less than 5%. The flow rate can also be detected by a flow meter, and when the set value is reached, the three-way valve is closed to 70%. Further, to prevent the pre-cooling mode and the natural cooling mode from switching back and forth, the single compressor lower limit speed runs for a period of time before switching to the natural cooling mode. When the compressor lower limit speed is running, the three-way valve is converted to a regulating type, and the supply air temperature setting value is used as the target value. The valve is closed to reduce the cooling output of the heat exchange coil 1 to avoid a large drop in the supply air temperature. Each setting parameter can be adjusted according to the situation, all within the protection scope of the present invention.

[0047] On the basis of the dual cold source refrigeration system provided in the above specific embodiments, the heat exchange coil 1 and the refrigeration coil 2 are integrally processed and formed, the heat exchange coil 1 is located on the windward side, and the refrigeration coil 2 is located on the air supply side. When a single system is running, since it is an integrated coil, a row of fins of the unused coil will also participate in the heat exchange, and the heat exchange performance is increased by 5%-10%, and the energy efficiency of the whole machine is improved. The heat exchange coil 1 on the windward side adopts a water coil, and the refrigeration coil 2 on the air supply side adopts a fluorine coil. On the one hand, the water coil provides a pre-cooling effect, and on the other hand, it can prevent the fluorine coil from freezing and cracking when the temperature is low.

[0048] A specific embodiment of the present invention provides a control method for a dual cold source refrigeration system, comprising the steps of:

[0049] Obtaining the inlet temperature and return air temperature of the heat exchange medium of the heat exchange coil 1;

[0050] Compare the inlet and return air temperatures;

[0051] If the inlet temperature is lower than the return air temperature, the difference between the two is calculated. If the difference is lower than the preset temperature, the pre-cooling mode is entered, and the compressor 5 is controlled to start, and the heat exchange medium is controlled to flow through the heat exchange coil 1 and the heat exchange plate 3. If the difference is higher than the preset temperature, the natural cooling mode is entered, and the compressor 5 is controlled to shut down, and the heat exchange medium is controlled to flow through the heat exchange coil 1 but not through the heat exchange plate 3.

[0052] If the inlet temperature is greater than the return air temperature, the mechanical cooling mode is entered, and the compressor 5 is controlled to start, and the heat exchange medium is controlled to flow through the heat exchange plate 3 and not through the heat exchange coil 1. The specific working method is as described above.

[0053] The real-time flow rate of the heat exchange coil 1 is obtained; if the real-time flow rate is greater than the preset flow rate, the opening of the three-way valve is reduced to the preset value.

[0054] The dual cold source refrigeration system and control method provided by the present invention are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A dual cold source refrigeration system, characterized in that: The invention comprises a heat exchange coil (1), a refrigeration coil (2), a heat exchange plate (3), an electronic expansion valve (4) and a compressor (5), wherein the heat exchange coil (1) and the refrigeration coil (2) are in contact with each other, the inlet of the heat exchange coil (1) is connected to a system output port (6), the outlet of the heat exchange coil (1) is connected to a heat exchange inlet of the heat exchange plate (3), the heat exchange outlet of the heat exchange plate (3) is connected to a system return port (7), the inlet of the refrigeration coil (2) is connected to a refrigeration outlet of the heat exchange plate (3) via the electronic expansion valve (4), and the outlet of the refrigeration coil (2) is connected to a refrigeration inlet of the heat exchange plate (3) via the compressor (5).

2. The dual cold source refrigeration system according to claim 1, characterized in that: It also includes a control valve group and a controller that are communicatively connected, wherein the controller controls the conduction state of the control valve group and the start and stop of the compressor (5) according to the heat exchange medium inlet temperature and return air temperature of the heat exchange coil (1).

3. The dual cold source refrigeration system according to claim 2, characterized in that: The control valve group comprises a first control valve (8), wherein the first control valve (8) is respectively connected to the heat exchange outlet of the heat exchange plate (3) and the system return port (7), and controls the conduction state between the two.

4. The dual cold source refrigeration system according to claim 3, characterized in that: The control valve group comprises a second control valve (9), wherein the second control valve (9) is respectively connected to the heat exchange inlet of the heat exchange plate (3) and the system return port (7), and controls the conduction state between the two.

5. The dual cold source refrigeration system according to claim 4, characterized in that: The control valve group comprises a third control valve (10), wherein the third control valve (10) is respectively connected to the heat exchange inlet of the heat exchange plate (3) and the inlet and outlet of the heat exchange coil (1), and controls the flow opening.

6. The dual cold source refrigeration system according to claim 5, characterized in that: The first control valve (8) and the second control valve (9) are two-way valves, and the third control valve (10) is a three-way valve.

7. The dual cold source refrigeration system according to any one of claims 1 to 6, characterized in that: The heat exchange coil (1) and the refrigeration coil (2) are integrally formed, the heat exchange coil (1) is located on the windward side, and the refrigeration coil (2) is located on the air supply side.

8. A control method for a dual cold source refrigeration system, characterized in that: The dual cold source refrigeration system according to any one of claims 1 to 7 comprises the following steps: Obtaining the inlet temperature and return air temperature of the heat exchange medium of the heat exchange coil (1); comparing the inlet temperature and the return air temperature; If the inlet temperature is lower than the return air temperature, the difference between the two is calculated; if the difference is lower than a preset temperature, the compressor (5) is controlled to start, and the heat exchange medium is controlled to flow through the heat exchange coil (1) and the heat exchange plate (3); if the difference is higher than the preset temperature, the compressor (5) is controlled to stop, and the heat exchange medium is controlled to flow through the heat exchange coil (1) and not through the heat exchange plate (3).

9. The control method of the dual cold source refrigeration system according to claim 8, characterized in that: Includes steps: If the inlet temperature is greater than the return air temperature, the compressor (5) is controlled to start, and the heat exchange medium is controlled to flow through the heat exchange plate (3) and not flow through the heat exchange coil (1).

10. The control method of the dual cold source refrigeration system according to claim 9, characterized in that: Includes steps: Obtaining the real-time flow rate of the heat exchange coil (1); If the real-time flow rate is greater than the preset flow rate, the opening of the three-way valve is reduced to a preset value.

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