A plate heat exchanger and a control method thereof

Abstract

The present invention relates to the field of refrigeration and air conditioning technology, and in particular to a plate heat exchanger and a control method thereof. The control method comprises the following steps: obtaining the outlet temperature T of the refrigerant in a heat exchange module; and adjusting the refrigerant flow rate and the refrigerant flow rate based on the refrigerant outlet temperature T and a preset temperature. The control method of the plate heat exchanger provided by the present invention monitors the refrigerant outlet temperature, determines the freezing risk based on the outlet temperature, and reduces the freezing risk by adjusting the refrigerant flow rate and the refrigerant flow rate, thereby preventing the refrigerant inside the plate heat exchanger from freezing and damaging the heat exchanger.

Description

Technical Field

[0001] The present invention relates to the technical field of refrigeration and air conditioning, and in particular to a plate heat exchanger and a control method thereof. Background Art

[0002] For applications requiring simultaneous cooling of multiple rooms within a building, the most common solution is to use multi-split air conditioners, with refrigerant pipes running directly to each room, allowing heat exchange between the refrigerant and the air within the room to achieve cooling. Currently, the mainstream refrigerant used in multi-split air conditioners is R410A, which has a high greenhouse effect and fails to meet environmental standards, and has been explicitly phased out under international conventions. R290 is an internationally recognized environmentally friendly refrigerant, but it is flammable, and there are strict international regulations regarding its leakage risk. If this refrigerant is used directly in current multi-split air conditioners, with refrigerant pipes running directly to each room, there is a risk of flammable refrigerant leaking into the room, which is prohibited under current regulations. A possible solution is to use a plate heat exchanger as the evaporator and water as the secondary refrigerant. The refrigerant in the multi-split air conditioner transfers its cooling energy to the secondary refrigerant through the plate heat exchanger. The secondary refrigerant is then piped to each room, exchanging heat with the air within the room to achieve cooling.

[0003] For plate heat exchangers that use R290 as refrigerant and water as coolant, once the water in the plate heat exchanger drops below 0°C, it will freeze and expand in volume, which may burst the plate heat exchanger, making the entire air conditioner unable to work or even scrapped.

[0004] In view of this, how to prevent water from freezing in a plate heat exchanger that uses R290 as refrigerant and water as coolant is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] In order to solve the problem of water freezing in plate heat exchangers that use R290 as the refrigerant and water as the coolant in the prior art, the present invention provides a plate heat exchanger that uses different refrigerant or coolant flow paths at different water outlet temperatures to prevent the coolant from freezing and bursting the plates, thereby solving the problem of water freezing in plate heat exchangers in the prior art.

[0006] The technical solution adopted by the present invention to solve its technical problem is:

[0007] A control method for a plate heat exchanger comprises the following steps:

[0008] Obtain the outlet temperature T of the coolant in the heat exchange module;

[0009] The refrigerant flow rate and the brine flow rate are adjusted according to the outlet temperature T of the brine and the preset temperature.

[0010] Optionally, adjusting the refrigerant flow rate and the brine flow rate according to the brine outlet temperature T and a preset temperature includes:

[0011] Comparing the outlet temperature T of the brine with a first preset temperature T1 to determine whether the outlet temperature T of the brine is less than the first preset temperature T1;

[0012] If the outlet temperature T of the brine is lower than the first preset temperature T1, the outlet temperature T of the brine is compared with the second preset temperature T2 to determine whether the outlet temperature T of the brine is higher than the second preset temperature T2;

[0013] If the outlet temperature T of the brine is greater than the second preset temperature T2, the flow rate of the refrigerant flow regulating pipeline is adjusted according to the outlet temperature T of the brine, the first preset temperature T1, and the second preset temperature T2;

[0014] If the outlet temperature T of the brine is not greater than the second preset temperature T2, the flow rate of the refrigerant flow regulating pipeline is adjusted to the maximum, and the brine flow regulating pipeline is opened.

[0015] Optionally, adjusting the flow of the refrigerant flow regulating pipeline according to the outlet temperature T of the refrigerant, the first preset temperature T1, and the second preset temperature T2 includes: adjusting the opening X of the electric regulating valve on the refrigerant flow regulating pipeline according to the outlet temperature T of the refrigerant, the first preset temperature T1, and the second preset temperature T2.

[0016] Optionally, adjusting the opening X of the electric regulating valve on the refrigerant flow regulating pipeline according to the outlet temperature T of the refrigerant, the first preset temperature T1, and the second preset temperature T2 includes: calculating the opening X of the electric regulating valve according to the following formula: X = (T-T1) / (T2-T1)*100%.

[0017] Optionally, the value of T1 is 2-4°C; the value of T2 is 0°C.

[0018] Another object of the present invention is to provide a plate heat exchanger that is controlled according to the control method of the plate heat exchanger as described above;

[0019] The plate heat exchanger includes a heat exchange module, a refrigerant flow distribution module, a brine flow distribution module and a control module; wherein,

[0020] The refrigerant flow distribution module and the brine flow distribution module are both connected to the heat exchange module, and the heat exchange module, the refrigerant flow distribution module and the brine flow distribution module are all electrically connected to the control module;

[0021] The control module is used to obtain the outlet temperature T of the coolant in the heat exchange module, and control the operation of the refrigerant flow distribution module and the coolant flow distribution module according to the outlet temperature T of the coolant and the preset temperature to adjust the refrigerant flow and the coolant flow.

[0022] Optionally, the heat exchange module includes a front cover plate, a heat exchange plate and a rear cover plate connected in sequence; the front cover plate is provided with a first coolant outlet;

[0023] The control module includes a controller and a temperature sensor;

[0024] The temperature sensor is arranged at the first outlet of the coolant;

[0025] The controller is electrically connected to the temperature sensor.

[0026] Optionally, the refrigerant flow distribution module includes a refrigerant input pipeline, a refrigerant output pipeline, a refrigerant flow regulating pipeline and a collecting main pipe; a refrigerant input port is provided on the front cover plate, and a refrigerant second output port is provided on the rear cover plate; the refrigerant input pipeline is connected to the refrigerant input port; one end of the refrigerant output pipeline is connected to the first refrigerant output port, and the other end is connected to the collecting main pipe; one end of the refrigerant flow regulating pipeline is connected to the second refrigerant output port, and the other end is connected to the collecting main pipe, and the refrigerant flow regulating pipeline is communicated with the refrigerant input pipeline; a first solenoid valve is provided on the refrigerant flow regulating pipeline; the first solenoid valve is electrically connected to the controller.

[0027] Optionally, the refrigerant flow distribution module includes a refrigerant input pipeline, a refrigerant output pipeline and a refrigerant flow regulating pipeline; a refrigerant input port and a refrigerant output port are provided on the front cover; the refrigerant input pipeline is connected to the refrigerant input port, the refrigerant output pipeline is connected to the refrigerant output port, the refrigerant flow regulating pipeline is provided between the refrigerant input pipeline and the refrigerant output pipeline, and a second solenoid valve is provided on the refrigerant flow regulating pipeline; the second solenoid valve is electrically connected to the controller.

[0028] Optionally, an electric regulating valve is further provided on the refrigerant flow regulating pipeline; the electric regulating valve is electrically connected to the controller.

[0029] The beneficial effects of the present invention are:

[0030] The control method for a plate heat exchanger provided by the present invention monitors the outlet temperature of the refrigerant, determines the freezing risk based on the outlet temperature, and reduces the freezing risk by adjusting the refrigerant flow rate and the refrigerant flow rate, thereby preventing the refrigerant inside the plate heat exchanger from freezing and heaving and damaging the heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention will be further described below with reference to the accompanying drawings and examples.

[0032] Figure 1 It is a flow chart of the plate heat exchanger control method of the present invention;

[0033] Figure 2 Schematic diagram of the flow of fluid in the plate heat exchanger during normal operation of the present invention;

[0034] Figure 3 Schematic diagram of the flow of fluid in the plate heat exchanger when the outlet temperature of the brine is lower than the first preset temperature and higher than the second preset temperature in the present invention;

[0035] Figure 4 Schematic diagram of the flow of fluid in the plate heat exchanger when the outlet temperature of the brine is not greater than the second preset temperature in the present invention;

[0036] Figure 5 It is a schematic diagram of the flow of fluid in the plate heat exchanger when local flow of the refrigerant is blocked in the present invention.

[0037] In the figure: 1-heat exchange module; 11-front cover; 111-first coolant output port; 112-coolant input port; 113-refrigerant input port; 114-refrigerant output port; 12-heat exchange plate; 13-rear cover; 131-second coolant output port; 2-refrigerant flow distribution module; 21-refrigerant input pipeline; 22-refrigerant output pipeline; 23-refrigerant flow regulating pipeline; 231-second solenoid valve; 232-electric regulating valve; 233-third one-way valve; 3-coolant flow distribution module; 31-coolant input pipeline; 32-coolant output pipeline; 321-second one-way valve; 33-coolant flow regulating pipeline; 331-first solenoid valve; 332-first one-way valve; 34-collecting main pipe; 4-control module; 41-controller; 42-temperature sensor. DETAILED DESCRIPTION

[0038] The present invention will now be described in further detail. The embodiments described below are exemplary and intended to explain the present invention, but should not be construed as limiting the present invention. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.

[0039] In the description of the present invention, it should be understood that the terms "first" and "second" are used only to simplify the description and should not be understood to indicate or imply relative importance, or implicitly specify the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise specifically defined.

[0040] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" the first feature may include the first feature being in direct contact with the second feature, or may include the first feature being in contact with the second feature through another feature between them instead of being in direct contact. Moreover, a first feature being "above," "above," and "above" the second feature includes the first feature being directly above or obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" the second feature includes the first feature being directly below or obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0041] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0042] In order to solve the problem of water freezing in the plate heat exchanger using R290 as the refrigerant and water as the coolant in the prior art, the present invention provides a control method for the plate heat exchanger, see Figure 1 As shown, the following steps are included:

[0043] S1: Obtain the outlet temperature T of the coolant in the heat exchange module;

[0044] S2: Regulate the refrigerant flow rate and the brine flow rate according to the brine outlet temperature T and the preset temperature.

[0045] In the present invention, regulating the refrigerant flow rate specifically refers to regulating the flow rate of the refrigerant entering the heat exchange module; regulating the brine flow rate specifically refers to regulating the flow rate of the brine entering the heat exchange module.

[0046] The heat exchange module in the plate heat exchanger is the place where the refrigerant and the coolant exchange heat; the outlet temperature T of the coolant in the heat exchange module is the temperature of the coolant after the heat exchange. Therefore, in the refrigeration system, if the outlet temperature T of the coolant is too low, there will be a risk of frost heave; based on this, the present invention obtains the outlet temperature T of the coolant and compares the obtained outlet temperature T with the preset temperature to determine whether there is a risk of frost heave; if it is determined that there is no risk of frost heave, the plate heat exchanger can be controlled to operate in normal mode, that is, the refrigerant flow rate and the coolant flow rate can both use normal flow rates; on the contrary, if the judgment result is that there is a risk of frost heave, the plate heat exchanger can be controlled to operate in anti-frost heave mode, that is, the refrigerant flow rate and the coolant flow rate are adjusted to reduce the risk of frost heave.

[0047] The preset temperature in the present invention can be set according to the type of coolant, specifically according to the freezing temperature of the coolant, so as to ensure sufficient cooling capacity and the highest possible energy efficiency while preventing frost heave.

[0048] The control method for a plate heat exchanger provided by the present invention monitors the outlet temperature of the refrigerant, determines the freezing risk based on the outlet temperature, and reduces the freezing risk by adjusting the refrigerant flow rate and the refrigerant flow rate, thereby preventing the refrigerant inside the plate heat exchanger from freezing and heaving and damaging the heat exchanger.

[0049] Specifically, adjusting the refrigerant flow rate and the brine flow rate according to the brine outlet temperature T and the preset temperature includes:

[0050] Comparing the outlet temperature T of the brine with the first preset temperature T1 to determine whether the outlet temperature T of the brine is less than the first preset temperature T1;

[0051] If the outlet temperature T of the brine is not less than the first preset temperature T1, it is determined that there is no risk of freezing of the brine. Therefore, there is no need to activate the anti-freeze mode. In the present invention, the brine flow regulating pipeline and the refrigerant flow regulating pipeline are closed. In other words, the plate heat exchanger operates in normal mode, and both the refrigerant flow rate and the brine flow rate can be normal.

[0052] If the outlet temperature T of the coolant is lower than the first preset temperature T1, it is determined that there is a risk of the coolant freezing. Therefore, it is necessary to adjust the refrigerant flow rate entering the heat exchange module and the coolant flow rate. In order to improve the anti-freezing effect, the present invention preferably further compares the outlet temperature T of the coolant with the second preset temperature T2 if the outlet temperature T of the coolant is lower than the first preset temperature T1 to determine whether the outlet temperature T of the coolant is higher than the second preset temperature T2. If the outlet temperature T of the coolant is higher than the second preset temperature T2, it is determined that the coolant has a certain risk of freezing, but the risk is relatively small. At this time, the coolant flow regulating pipeline is still in the closed state, and the refrigerant flow regulating pipeline is opened so that the refrigerant is divided into two circuit, reducing the flow of refrigerant entering the heat exchange module to avoid freezing of the coolant due to excessively low temperature; and, the present invention preferably adjusts the flow of the refrigerant flow regulating pipeline according to the coolant outlet temperature T, the first preset temperature T1, and the second preset temperature T2, so as to take into account both the anti-freezing effect and the refrigeration effect as much as possible; on the contrary, if the coolant outlet temperature T is not greater than the second preset temperature T2, it is determined that the risk of coolant freezing is greater. At this time, the flow of the refrigerant flow regulating pipeline is adjusted to the maximum to minimize the refrigerant flow entering the heat exchange module, and the coolant flow regulating pipeline is opened to divide the coolant into two paths, reducing the coolant flow in the heat exchange module, thereby reducing the risk of frost heave damage to the plate heat exchanger.

[0053] The present invention preferably adjusts the flow of the refrigerant flow regulating pipeline according to the outlet temperature T of the refrigerant, the first preset temperature T1, and the second preset temperature T2, including: adjusting the opening X of the electric regulating valve on the refrigerant flow regulating pipeline according to the outlet temperature T of the refrigerant, the first preset temperature T1, and the second preset temperature T2.

[0054] Furthermore, the present invention preferably adjusts the opening X of the electric regulating valve on the refrigerant flow regulating pipeline according to the outlet temperature T of the refrigerant, the first preset temperature T1, and the second preset temperature T2, including: calculating the opening X of the electric regulating valve according to the following formula: X = (T-T1) / (T2-T1)*100%.

[0055] The values ​​of the first preset temperature T1 and the second preset temperature T2 in the present invention are determined according to the coolant, specifically according to the freezing temperature of the coolant; the present invention preferably uses water as the coolant, and the value of T1 is preferably 2-4°C; the value of T2 is 0°C.

[0056] In summary, participate Figure 1 As shown, the plate heat exchanger control method provided by the present invention can be performed according to the following steps:

[0057] S1: Obtain the outlet temperature T of the coolant in the heat exchange module;

[0058] S21: Compare the outlet temperature T of the brine with the first preset temperature T1 to determine whether the outlet temperature T of the brine is less than the first preset temperature T1; if the outlet temperature T of the brine is less than the first preset temperature T1, proceed to step S23; otherwise, proceed to step S22;

[0059] S22: Close the secondary coolant flow regulating pipeline and the refrigerant flow regulating pipeline;

[0060] S23: Compare the outlet temperature T of the brine with the second preset temperature T2 to determine whether the outlet temperature T of the brine is greater than the second preset temperature T2; if the outlet temperature T of the brine is greater than the second preset temperature T2, proceed to step S24; otherwise, proceed to step S25;

[0061] S24: opening the refrigerant flow regulating pipeline and adjusting the flow of the refrigerant flow regulating pipeline according to the outlet temperature T of the secondary coolant, the first preset temperature T1, and the second preset temperature T2;

[0062] S25: Adjust the flow of the refrigerant flow regulating pipeline to the maximum, and open the refrigerant flow regulating pipeline.

[0063] The control method of the plate heat exchanger provided by the present invention can achieve different refrigerant and coolant flow distributions by monitoring the coolant outlet temperature, thereby meeting the distribution requirements under different frost heave risks.

[0064] Another object of the present invention is to provide a plate heat exchanger, which is controlled according to the control method of the plate heat exchanger described above; specifically, see Figure 2-Figure 5 As shown, the plate heat exchanger includes a heat exchange module 1, a refrigerant flow distribution module 2, a coolant flow distribution module 3 and a control module 4; wherein, the heat exchange module 1 has a refrigerant flow path and a coolant flow path, so that the refrigerant and the coolant can exchange heat in the heat exchange module; the refrigerant flow distribution module 2 and the coolant flow distribution module 3 are both connected to the heat exchange module 1, specifically, the refrigerant flow distribution module 2 is connected to the refrigerant flow path in the heat exchange module 1, for transporting the refrigerant into the heat exchange module 1; the coolant flow distribution module 3 is connected to the coolant flow path in the heat exchange module 1, for transporting the refrigerant into the heat exchange module 1; the coolant flow distribution module 3 is connected to the coolant flow path in the heat exchange module 1 The refrigerant flow path is connected and is used to transport the refrigerant into the heat exchange module 1; and the heat exchange module 1, the refrigerant flow distribution module 2 and the refrigerant flow distribution module 3 are all electrically connected to the control module 4; the control module 4 is used to obtain the outlet temperature T of the refrigerant in the heat exchange module 1, and judge whether there is a risk of freezing of the refrigerant in the heat exchange module 1 based on the outlet temperature T of the refrigerant and the preset temperature, and then control the operation of the refrigerant flow distribution module 2 and the refrigerant flow distribution module 3 according to the judgment result to adjust the refrigerant flow and the refrigerant flow to prevent the refrigerant from freezing.

[0065] The plate heat exchanger provided by the present invention monitors the outlet temperature T of the refrigerant, determines the freezing risk based on the outlet temperature, and reduces the freezing risk by adjusting the refrigerant flow rate and the refrigerant flow rate, thereby preventing the refrigerant inside the plate heat exchanger from freezing and heaving and damaging the heat exchanger.

[0066] Specifically, in order to facilitate the control module 4 to obtain the outlet temperature T of the brine, the heat exchange module 1 in the present invention includes a front cover plate 11, a heat exchange plate 12 and a rear cover plate 13 connected in sequence; a first brine outlet 111 is provided on the front cover plate 11, and the brine after heat exchange with the refrigerant in the heat exchange module 1 is output through the first brine outlet 111; the control module 4 includes a controller 41 and a temperature sensor 42; the temperature sensor 42 is provided at the first brine outlet 111, and it is further preferred that the temperature sensor 42 is provided on the outlet pipe at the first brine outlet 111, and the temperature obtained by the temperature sensor 42 is the brine outlet temperature T; the controller 41 is electrically connected to the temperature sensor 42, so that the brine outlet temperature T obtained by the temperature sensor 42 can be transmitted to the controller 41, and the controller 41 then controls the operation of the refrigerant flow distribution module 2 and the brine flow distribution module 3 according to the obtained brine outlet temperature T, thereby realizing the regulation of the refrigerant and brine flow in the heat exchange module 1.

[0067] In order to adjust the flow of the coolant, the present invention preferably includes a coolant flow distribution module 3 including a coolant input pipeline 31, a coolant output pipeline 32, a coolant flow regulating pipeline 33 and a collecting main pipe 34; a coolant input port 112 is provided on the front cover 11, and a coolant second output port 131 is provided on the rear cover 13, and the coolant input port 112 and the coolant first output port 111 are both communicated with the coolant flow path in the heat exchange module 1, the coolant input port 112 is communicated with the coolant second output port 131, the coolant input pipeline 31 is connected to the coolant input port 112, and one end of the coolant output pipeline 32 is connected to the coolant The first refrigerant output port 111 is connected, and the other end is connected to the collecting main pipe 34, so that the refrigerant can be transported into the heat exchange module 1 through the refrigerant input pipe 31, and the refrigerant in the heat exchange module 1 can be output through the refrigerant output pipe 32; one end of the refrigerant flow regulating pipe 33 is connected to the second refrigerant output port 131, and the other end is connected to the collecting main pipe 34; a first solenoid valve 331 is provided on the refrigerant flow regulating pipe 33; the first solenoid valve 331 is electrically connected to the controller 41, so that the opening and closing of the first solenoid valve 331 can be controlled by the controller 41 to realize the regulation of the refrigerant flow in the heat exchange module 1.

[0068] Specifically, when the plate heat exchanger is in operation, it operates in normal mode, or when there is no need to adjust the flow of the brine into the heat exchange module 1, the controller 41 controls the first solenoid valve 331 to be closed, so that all the brine is circulated in sequence through the brine input pipe 31, the brine input port 112, the brine flow path in the heat exchange module 1, the first brine output port 111, and the brine output pipe 32; on the contrary, when it is detected that the brine is at risk of freezing, the controller 41 controls the first solenoid valve 331 to be closed. When valve 331 is opened, the refrigerant runs in two paths. One path circulates along the refrigerant input pipeline 31, the refrigerant input port 112, the refrigerant flow path in the heat exchange module 1, the refrigerant output pipeline 32, and the collecting main pipe 34. The other path circulates through the refrigerant input pipeline 31, the refrigerant input port 112, the refrigerant second output port 131, the refrigerant flow regulating pipeline 33, and the collecting main pipe 34, thereby reducing the flow of the refrigerant in the heat exchange module 1 and reducing the risk of frost heave damage to the plate heat exchanger.

[0069] Furthermore, to facilitate maintenance, etc., the present invention preferably provides a first one-way valve 332 on the brine flow regulating pipeline 33 and a second one-way valve 321 on the brine output pipeline 32 .

[0070] In order to facilitate the regulation of the flow of refrigerant entering the heat exchange module 1, the present invention preferably provides a refrigerant flow distribution module 2 including a refrigerant input pipeline 21, a refrigerant output pipeline 22 and a refrigerant flow regulating pipeline 23; a refrigerant input port 113 and a refrigerant output port 114 are provided on the front end cover plate 11, and the refrigerant input port 113 and the refrigerant output port 114 are both connected to the refrigerant flow path in the heat exchange module 1; the refrigerant input pipeline 21 is connected to the refrigerant input port 113, and the refrigerant output pipeline 22 is connected to the refrigerant output port 114, and the refrigerant flow regulating pipeline 23 is provided between the refrigerant input pipeline 21 and the refrigerant output pipeline 22, and a second solenoid valve 231 is provided on the refrigerant flow regulating pipeline 23; the second solenoid valve 231 is electrically connected to the controller 41.

[0071] When the plate heat exchanger is in operation, it operates in normal mode, or when there is no need to adjust the flow of refrigerant entering the heat exchange module 1, the controller 41 controls the second solenoid valve 231 to be closed, and the refrigerant flows along the refrigerant input pipe 21, the refrigerant input port 113, the refrigerant flow path in the heat exchange module 1, the refrigerant output port 114 and the refrigerant output pipe 22; on the contrary, when it is detected that the refrigerant in the heat exchange module 1 has a risk of freezing, the controller 41 controls the second solenoid valve 231 to be opened, so that the refrigerant flow path is divided into two. One path flows along the refrigerant input pipeline 21, the refrigerant input port 113, the refrigerant flow path in the heat exchange module 1, the refrigerant output port 114 and the refrigerant output pipeline 22, and the other path runs along the refrigerant input pipeline 21, the refrigerant flow regulating pipeline 23 and the refrigerant output pipeline 22. That is to say, a part of the refrigerant is controlled not to enter the heat exchange module 1, and is directly circulated outside the heat exchange module 1, thereby reducing the flow rate of the refrigerant in the heat exchange module 1, thereby reducing the cooling capacity exchanged with the coolant, and reducing the risk of freezing of the coolant in the heat exchange module 1.

[0072] In order to facilitate the adjustment of the flow rate of the refrigerant in the heat exchange module 1 according to the outlet temperature T of the refrigerant, the present invention preferably provides an electric regulating valve 232 on the refrigerant flow regulating pipeline 23; the electric regulating valve 232 is electrically connected to the controller 41, so that during operation, the controller 41 adjusts the opening X of the electric regulating valve 232 according to the outlet temperature T of the refrigerant, the first preset temperature T1, and the second preset temperature T2. The opening X ranges from 0 to 100%. Specifically, the opening X of the electric regulating valve 232 is calculated according to the following formula: X = (T-T1) / (T2-T1)*100%.

[0073] To facilitate maintenance, etc., the present invention preferably further provides a third one-way valve 233 on the refrigerant flow regulating pipeline 23 .

[0074] In summary, during the operation of the plate heat exchanger provided by the present invention, when the outlet temperature T of the coolant is not less than the first preset temperature T1, the plate heat exchanger operates in normal mode. Figure 2 As shown, the refrigerant flow regulating pipeline 23 and the coolant flow regulating pipeline 33 are both closed, and the refrigerant flows along the refrigerant input pipeline 21, the refrigerant input port 113, the refrigerant flow path in the heat exchange module 1, the refrigerant output port 114 and the refrigerant output pipeline 22; the coolant flows along the coolant input pipeline 31, the coolant input port 112, the coolant flow path in the heat exchange module 1, the coolant first output port 111, and the coolant output pipeline 32.

[0075] When the outlet temperature T of the coolant is less than the first preset temperature T1 and greater than the second preset temperature T2, see Figure 3As shown, the refrigerant flow regulating pipeline 33 is still in a closed state, the refrigerant flow regulating pipeline 23 is opened, and the opening X of the electric regulating valve 232 is determined according to the formula X=(T-T1) / (T2-T1)*100% to achieve the regulation of the refrigerant flow.

[0076] When the outlet temperature T of the coolant is less than the first preset temperature T1 and not greater than the second preset temperature T2, refer to Figure 4 As shown, the brine flow regulating line 33 and the refrigerant flow regulating line 23 are opened, and the opening X of the electric regulating valve 232 is adjusted to the maximum. At this time, the brine and refrigerant are divided into two paths. The refrigerant flow path is as follows: one path flows along the refrigerant input line 21, the refrigerant input port 113, the refrigerant flow path in the heat exchange module 1, the refrigerant output port 114, and the refrigerant output line 22; the other path flows along the refrigerant input line 21, the refrigerant flow regulating line 23, and the refrigerant output line 22. The brine flow path is as follows: one path flows along the brine input line 31, the brine input port 112, the brine flow path in the heat exchange module 1, the brine output line 32, and the collecting manifold 34; the other path flows through the brine input line 31, the brine input port 112, the second brine output port 131, the brine flow regulating line 33, and the collecting manifold 34.

[0077] In addition, with the plate heat exchanger provided by the present invention, if local icing occurs in the plate heat exchanger causing flow obstruction, part of the coolant between the plates can also flow out from the rear end cover hole 13, see Figure 5 As shown, the risk of ice heave is further reduced.

[0078] The plate heat exchanger provided by the present invention adopts different refrigerant flow paths and coolant flow paths at different coolant outlet temperatures to prevent the coolant from freezing and expanding and breaking the plates; specifically, when the coolant outlet temperature is too low, the refrigerant and coolant are divided into two paths, which respectively reduce the refrigerant flow rate and coolant flow rate entering the heat exchange module 1 when the coolant outlet temperature is too low, thereby preventing the water inside the plate heat exchanger from freezing and expanding and damaging the heat exchanger when the coolant outlet temperature is too low; the structure of the present invention ensures that even when local flow is not smooth between the plates, the coolant between the plates can also flow out from the coolant second outlet 131 on the rear end cover plate 13, reducing the risk of the heat exchanger expanding due to coolant freezing and blockage.

[0079] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. A control method for a plate heat exchanger, characterized in that: The plate heat exchanger comprises a heat exchange module (1), a refrigerant flow distribution module (2), and a secondary refrigerant flow distribution module (3); The heat exchange module (1) comprises a front cover plate (11), a heat exchange plate (12), and a rear cover plate (13) connected in sequence; a first coolant outlet (111) is provided on the front cover plate (11); The refrigerant flow distribution module (2) comprises a refrigerant input pipeline (21), a refrigerant output pipeline (22), and a refrigerant flow regulating pipeline (23); a refrigerant input port (113) and a refrigerant output port (114) are provided on the front cover plate (11); the refrigerant input pipeline (21) is connected to the refrigerant input port (113), the refrigerant output pipeline (22) is connected to the refrigerant output port (114), and the refrigerant flow regulating pipeline (23) is provided between the refrigerant input pipeline (21) and the refrigerant output pipeline (22); The brine flow distribution module (3) comprises a brine input pipeline (31), a brine output pipeline (32), a brine flow regulating pipeline (33) and a collecting main pipe (34); a brine input port (112) is provided on the front cover plate (11), and a brine second output port (131) is provided on the rear cover plate (13); the brine input pipeline (31) is connected to the brine input port (112); one end of the brine output pipeline (32) is connected to the brine first output port (111), and the other end is connected to the collecting main pipe (34); one end of the brine flow regulating pipeline (33) is connected to the brine second output port (131), and the other end is connected to the collecting main pipe (34), and the brine flow regulating pipeline (33) is in communication with the brine input pipeline (31); The control method comprises the following steps: Obtaining the outlet temperature T of the refrigerant in the heat exchange module (1); Adjusting the refrigerant flow rate and the brine flow rate according to the brine outlet temperature T and the preset temperature; Adjusting the refrigerant flow rate and the brine flow rate according to the brine outlet temperature T and the preset temperature includes: Comparing the outlet temperature T of the brine with a first preset temperature T1 to determine whether the outlet temperature T of the brine is less than the first preset temperature T1; If the outlet temperature T of the brine is lower than the first preset temperature T1, the outlet temperature T of the brine is compared with the second preset temperature T2 to determine whether the outlet temperature T of the brine is higher than the second preset temperature T2; If the outlet temperature T of the secondary coolant is greater than the second preset temperature T2, the flow rate of the refrigerant flow regulating pipeline (23) is adjusted according to the outlet temperature T of the secondary coolant, the first preset temperature T1, and the second preset temperature T2; If the outlet temperature T of the secondary coolant is not greater than the second preset temperature T2, the flow rate of the refrigerant flow regulating pipeline (23) is adjusted to the maximum, and the secondary coolant flow regulating pipeline (33) is opened.

2. The control method of the plate heat exchanger according to claim 1, characterized in that: Adjusting the flow of the refrigerant flow regulating pipeline according to the outlet temperature T of the coolant, the first preset temperature T1, and the second preset temperature T2 includes: adjusting the opening X of the electric regulating valve on the refrigerant flow regulating pipeline according to the outlet temperature T of the coolant, the first preset temperature T1, and the second preset temperature T2.

3. The control method of the plate heat exchanger according to claim 2, characterized in that: Adjusting the opening X of the electric regulating valve on the refrigerant flow regulating pipeline according to the outlet temperature T of the refrigerant, the first preset temperature T1, and the second preset temperature T2 includes: calculating the opening X of the electric regulating valve according to the following formula: X=(T-T1) / (T2-T1)*100%.

4. The control method for a plate heat exchanger according to any one of claims 1 to 3, characterized in that: The value of T1 is 2~4℃; the value of T2 is 0℃.

5. A plate heat exchanger, characterized in that: Controlling according to the control method of the plate heat exchanger according to any one of claims 1 to 4; The plate heat exchanger further includes a control module (4); wherein, The refrigerant flow distribution module (2) and the secondary coolant flow distribution module (3) are both connected to the heat exchange module (1), and the heat exchange module (1), the refrigerant flow distribution module (2) and the secondary coolant flow distribution module (3) are all electrically connected to the control module (4); The control module (4) is used to obtain the outlet temperature T of the coolant in the heat exchange module (1), and control the operation of the refrigerant flow distribution module (2) and the coolant flow distribution module (3) according to the outlet temperature T of the coolant and a preset temperature, so as to adjust the refrigerant flow and the coolant flow.

6. The plate heat exchanger according to claim 5, characterized in that The control module (4) includes a controller (41) and a temperature sensor (42); The temperature sensor (42) is arranged at the first coolant output port (111); The controller (41) is electrically connected to the temperature sensor (42).

7. The plate heat exchanger according to claim 6, characterized in that A first solenoid valve (331) is provided on the refrigerant flow regulating pipeline (33); the first solenoid valve (331) is electrically connected to the controller (41).

8. The plate heat exchanger according to claim 6, characterized in that A second solenoid valve (231) is provided on the refrigerant flow regulating pipeline (23); the second solenoid valve (231) is electrically connected to the controller (41).

9. The plate heat exchanger according to claim 8, characterized in that An electric regulating valve (232) is also provided on the refrigerant flow regulating pipeline (23); the electric regulating valve (232) is electrically connected to the controller (41).

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