A low-temperature preservation cabinet and a control method of a variable frequency fan thereof

Abstract

The application discloses a low-temperature preservation cabinet and a control method of a variable-frequency fan thereof, and belongs to the technical field of refrigeration of the low-temperature preservation cabinet. The low-temperature preservation cabinet comprises a cabinet body and a compressor chamber, and the compressor chamber is internally provided with a condenser, a variable-frequency fan, a compressor, an electric control box and a sensor; the condenser is fixed at the front part of the compressor chamber; the variable-frequency fan is fixed on the condenser; the electric control box is fixed at the right rear part of the compressor chamber and is connected with the compressor and the variable-frequency fan through a circuit. The method reduces the noise and energy consumption of the low-temperature preservation cabinet, prolongs the service life of the fan, reduces the maintenance rate of the low-temperature preservation cabinet and lowers the cost; the rotating speed of the fan of the low-temperature preservation cabinet is associated with the condenser temperature, the ambient temperature and the start-stop state of the compressor, the control method is various, different maximum rotating speed values are set according to the start and stop states of the compressor, the noise and energy consumption are reduced, the effective use of energy is better promoted, the cost investment is reduced, and the sustainable development is favorable.

Description

Technical Field

[0001] This invention belongs to the field of refrigeration technology for low-temperature storage cabinets, specifically relating to a low-temperature storage cabinet and a control method for its variable frequency fan. Background Technology

[0002] Low-temperature storage cabinets have two main heat dissipation methods: radiation and convection. Radiation has a low rate of heat dissipation and low efficiency. Convection heat dissipation transfers heat from the low-temperature storage cabinet through a fan, which is greatly affected by the wind speed. The fan speed of existing low-temperature storage cabinets is generally fixed and maintains the highest speed during operation. However, if the fan speed is maintained at a high speed when the temperature of the low-temperature storage cabinet is low, it will not be conducive to reducing the energy consumption and noise of the low-temperature storage cabinet.

[0003] The fans used in existing cryogenic storage cabinets generally have a fixed speed, the control method is relatively simple, and they are noisy, consume a lot of electricity, have a short lifespan, and are costly. Therefore, it is necessary to design a control method for variable frequency fans in cryogenic storage cabinets to reduce noise and energy consumption, extend fan life, reduce the maintenance rate of cryogenic storage cabinets, and reduce costs. Summary of the Invention

[0004] In view of the above-mentioned technical problems existing in the prior art, the present invention proposes a control method for a low-temperature storage cabinet and its variable frequency fan. The design is reasonable, overcomes the shortcomings of the prior art, and has good effect.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A low-temperature storage cabinet includes a cabinet body and a compressor chamber. The compressor chamber is equipped with a condenser, a variable frequency fan, a compressor, an electrical control box, and sensors. The condenser is fixed at the front of the compressor chamber. The variable frequency fan is fixed on the condenser. The electrical control box is fixed at the rear right of the compressor chamber and is connected to the compressor and the variable frequency fan via wiring.

[0007] Preferably, the variable frequency fan includes a high-temperature stage variable frequency fan and a low-temperature stage variable frequency fan, which are fixed on both sides of the condenser; the compressor includes a high-temperature stage compressor and a low-temperature stage compressor.

[0008] Preferably, the speed range of the variable frequency fan is N1 to N3, and different maximum speed values ​​are set for the start and stop states of the compressor: when both compressors, namely the high-temperature stage compressor and the low-temperature stage compressor, are started, if the variable frequency fan needs to rotate at the highest speed, it will rotate at the highest speed of N3; when both compressors are stopped, if the variable frequency fan needs to rotate at the highest speed, it will rotate at the highest speed of N2.

[0009] Furthermore, this invention also mentions a control method for the variable frequency fan of a low-temperature storage cabinet, which uses the low-temperature storage cabinet as described above, and specifically includes the following steps:

[0010] Variable frequency fans include two modes: energy-saving mode and dust removal mode. The specific implementation methods are as follows:

[0011] Step 1: In energy-saving mode, the specific steps are as follows:

[0012] Step 1.1: When both compressors of the low-temperature storage cabinet are in the start-up state, the high-temperature stage variable frequency fan operates under the following conditions:

[0013] The low-temperature storage cabinet monitors the condenser temperature and ambient temperature in real time.

[0014] When the condenser temperature is ≥ T, where T = A - 5℃, and A is the condenser temperature when the "condenser dirty" indicator light starts to illuminate, the high-temperature variable frequency fan enters high-speed mode at the highest speed N3.

[0015] When the condenser temperature is <T, if the temperature difference is ≥20℃, the high-temperature stage variable frequency fan enters high-speed mode at the highest speed N3; if the temperature difference is ≤4℃, the high-temperature stage variable frequency fan enters low-speed mode at the lowest speed N1.

[0016] If 4℃ < temperature difference < 20℃, the high-temperature variable frequency fan enters the variable speed state and rotates at a variable speed according to the linear equation y1 = 43.75x1 + 725; where x1 represents the temperature difference and y1 represents the speed of the high-temperature variable frequency fan; temperature difference = condenser temperature - ambient temperature.

[0017] Step 1.2: When both compressors are in the start-up state, the low-temperature stage variable frequency fan operates under the following conditions:

[0018] The low-temperature storage cabinet monitors the ambient temperature in real time;

[0019] When the ambient temperature is ≥ H2, where H2 = B - 5℃, and B is the ambient temperature when the "Ambient Temperature Too High" indicator light starts to illuminate, the low-temperature stage variable frequency fan enters high-speed mode at the highest speed N3.

[0020] When the ambient temperature is ≤ H1, where H1 = H2 - 10, the low-temperature stage variable frequency fan enters the low-speed mode at the lowest speed N1.

[0021] When H1 < ambient temperature < H2, the low-temperature variable frequency fan rotates at a variable speed according to the linear equation y2 = 70x2 - 500, entering the variable speed mode; where x2 represents the ambient temperature and y2 represents the speed of the low-temperature variable frequency fan.

[0022] Step 1.3: When both compressors of the low-temperature storage cabinet are stopped, the two variable frequency fans, namely the high-temperature stage variable frequency fan and the low-temperature stage variable frequency fan, operate simultaneously under the following conditions:

[0023] The low-temperature storage cabinet monitors the ambient temperature in real time. When the ambient temperature is ≤H3, where H3 = H1 - 8℃, the two variable frequency fans enter the stop mode.

[0024] When the ambient temperature H3 < ambient temperature ≤ H1, the two variable frequency fans enter the low-speed mode at the lowest speed N1.

[0025] When the ambient temperature H1 < ambient temperature < H2, the two variable frequency fans rotate at different speeds according to the linear equation y3 = 20x3 + 500, entering the variable speed mode; where x3 represents the ambient temperature and y3 represents the rotational speed of the two variable frequency fans.

[0026] When the ambient temperature is ≥ H2, the two variable frequency fans enter high-speed mode at the highest speed N2.

[0027] Step 2: Dust removal mode;

[0028] The low-temperature storage cabinet monitors the status of the variable frequency fan and compressor in real time. Every month, when the two compressors stop rotating, after a 30-second delay, the two variable frequency fans automatically enter the reverse control mode and run in reverse at the highest speed N2 for 3 minutes. During the reverse process, when the temperature inside the low-temperature storage cabinet is higher than the set temperature of -0.2℃, the two variable frequency fans stop reversing.

[0029] Preferably, the high-speed mode is a mode that operates at a constant speed at the highest speed; the low-speed mode is a mode that operates at a constant speed at the lowest speed; the variable speed mode is a mode that operates at a variable speed according to the linear equation y=kx+b; and the reverse control mode is a mode in which the variable frequency fan rotates in the opposite direction to the original rotation direction.

[0030] The beneficial technical effects of this invention are as follows:

[0031] This invention reduces noise and energy consumption in cryogenic storage cabinets, extends fan life, reduces maintenance rates, and lowers costs. It links the fan speed of the cryogenic storage cabinet to its condenser temperature, ambient temperature, and compressor start / stop status, allowing for diverse control methods. Different maximum speed values ​​are set for compressor start and stop states, further reducing noise and energy consumption. This invention promotes more efficient energy utilization, reduces cost input, and contributes to sustainable development. Attached Figure Description

[0032] Figure 1 This is a structural diagram of the compressor chamber of a low-temperature storage cabinet;

[0033] Figure 2 A schematic diagram showing that the condenser temperature is higher than T;

[0034] Figure 3 A schematic diagram showing a condenser temperature below T;

[0035] Figure 4 This is a schematic diagram of the control of a low-temperature stage variable frequency fan (when both compressors are on);

[0036] Figure 5 This is a schematic diagram of the control of two variable frequency fans (when both compressors are turned off). Detailed Implementation

[0037] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0038] The cryogenic storage cabinet consists of a cabinet body and a compressor compartment. The compressor compartment mainly contains a condenser, variable frequency fans (including high-temperature and low-temperature stage variable frequency fans), a compressor (including high-temperature and low-temperature stage compressors), an electrical control box, and sensors. The condenser is fixed at the front of the compressor compartment. The high-temperature and low-temperature stage variable frequency fans are fixed to the condenser, with the high-temperature stage fan on the left and the low-temperature stage fan on the right. The electrical control box is fixed at the rear right of the compressor compartment and connects to the compressor and variable frequency fans. Figure 1 As shown.

[0039] The variable frequency fan's speed range is N1 to N3. Different maximum speed values ​​are set for the compressor's start-up and stop states: when both compressors are running, if the fan requires the highest speed, it will run at the maximum speed of N3; when both compressors are stopped, if the fan requires the highest speed, it will run at the maximum speed of N2. In this patent, the variable frequency fan's control can switch between high-speed, low-speed, variable-speed, and stop modes (N1 < N2 < N3) according to temperature conditions and the compressor's start-up and stop states. High-speed mode: operates at the highest constant speed; Low-speed mode: operates at the lowest constant speed; Variable-speed mode: operates at a variable speed according to the linear equation y = kx + b; Stop mode: shut down, not running; Reverse control mode: the variable frequency fan rotates in the opposite direction to its original rotation. The variable frequency fan includes two modes: energy-saving mode and dust removal mode, specifically implemented as follows:

[0040] (1) Energy-saving mode:

[0041] a. When both compressors are in the start-up state, the high-temperature stage variable frequency fan operates under the following conditions:

[0042] The low-temperature storage cabinet monitors the condenser temperature and ambient temperature in real time. When the condenser temperature is ≥T (T=A-5℃, A: condenser temperature when the "condenser dirty" indicator light starts to illuminate), the high-temperature stage variable frequency fan enters high-speed mode at its highest speed N3. Figure 2As shown; when the condenser temperature < T, if the temperature difference ≥ 20℃, the high-temperature stage variable frequency fan enters high-speed mode at its highest speed N3; if the temperature difference (temperature difference = condenser temperature - ambient temperature) ≤ 4℃, the high-temperature stage variable frequency fan enters low-speed mode at its lowest speed N1; if 4 < temperature difference < 20℃, the high-temperature stage variable frequency fan enters variable speed mode, rotating at a variable speed according to the linear equation y1 = 43.75x1 + 725 (x1 represents the temperature difference, y1 represents the speed of the high-temperature stage variable frequency fan), thus entering variable speed mode. Figure 3 As shown.

[0043] b. When both compressors are in the start-up state, the low-temperature stage variable frequency fan operates under the following conditions:

[0044] The low-temperature storage cabinet monitors the ambient temperature in real time. When the ambient temperature is ≥ H2 (H2 = B - 5℃, B: the ambient temperature when the "Ambient Temperature Too High" indicator light starts to illuminate), the low-temperature stage variable frequency fan enters high-speed mode at its highest speed N3; when the ambient temperature is ≤ H1 (H1 = H2 - 10℃), the low-temperature stage variable frequency fan enters low-speed mode at its lowest speed N1; when H1 < ambient temperature < H2, the low-temperature stage variable frequency fan rotates according to the linear equation y2 = 70x2 - 500 (x2 represents the ambient temperature, y2 represents the speed of the low-temperature stage variable frequency fan), entering variable speed mode; Figure 4 As shown.

[0045] c. When both compressors are stopped, the two variable frequency fans operate simultaneously under the following conditions:

[0046] The low-temperature storage cabinet monitors the ambient temperature in real time. When the ambient temperature is ≤H3 (H3 = H1 - 8℃), the two variable frequency fans enter a stop mode; when the ambient temperature H3 < ambient temperature ≤ H1, the two variable frequency fans enter a low-speed mode at the lowest speed N1; when the ambient temperature H1 < ambient temperature < H2, the two variable frequency fans rotate at varying speeds according to the linear equation y3 = 20x3 + 500 (x3 represents the ambient temperature, y3 represents the speed of the two variable frequency fans), entering a variable speed mode; when the ambient temperature is ≥H2 (including H2), the two variable frequency fans enter a high-speed mode at the highest speed N2, such as... Figure 5 As shown.

[0047] (2) Dust removal mode:

[0048] The low-temperature storage cabinet monitors the status of the variable frequency fan and compressor in real time. Every month, when the two compressors stop rotating, after a 30-second delay, the two variable frequency fans automatically enter the reverse control mode and run in reverse at the highest speed N2 for 3 minutes. During the reverse process, when the temperature inside the cabinet is higher than the set temperature -0.2℃, the two variable frequency fans stop reversing.

[0049] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A control method of a variable frequency fan of a cryopreservation cabinet, characterized by: A low-temperature storage cabinet is adopted, which includes a cabinet body and a compressor chamber. The compressor chamber is equipped with a condenser, a variable frequency fan, a compressor, an electrical control box, and sensors. The condenser is fixed at the front of the compressor chamber. The variable frequency fan is fixed on the condenser. The electrical control box is fixed at the rear right of the compressor chamber and is connected to the compressor and the variable frequency fan through wiring. The variable frequency fan includes a high-temperature stage variable frequency fan and a low-temperature stage variable frequency fan, which are fixed on both sides of the condenser. Compressors, including high-temperature stage compressors and low-temperature stage compressors; The speed range of the variable frequency fan is N1 to N3. Different maximum speed values ​​are set for the start and stop states of the compressor: when both compressors, namely the high-temperature stage compressor and the low-temperature stage compressor, are started, if the variable frequency fan needs to run at the highest speed, it will run at the maximum speed of N3. When both compressors stop, if the variable frequency fan needs to rotate at its highest speed, it will rotate at the highest speed of N2. This method specifically includes the following steps: Variable frequency fans include two modes: energy-saving mode and dust removal mode. The specific implementation methods are as follows: Step 1: In energy-saving mode, the specific steps are as follows: Step 1.1: When both compressors of the low-temperature storage cabinet are in the start-up state, the high-temperature stage variable frequency fan operates under the following conditions: The low-temperature storage cabinet monitors the condenser temperature and ambient temperature in real time. When the condenser temperature is ≥T, where T=A-5℃, A: the condenser temperature when the "condenser dirty" indicator light starts to illuminate, the high-temperature stage variable frequency fan enters high-speed mode at the highest speed N3. When the condenser temperature is <T, if the temperature difference is ≥20℃, the high-temperature stage variable frequency fan enters high-speed mode at the highest speed N3; if the temperature difference is ≤4℃, the high-temperature stage variable frequency fan enters low-speed mode at the lowest speed N1. If 4℃ < temperature difference < 20℃, the high-temperature variable frequency fan enters the variable speed state and rotates at a variable speed according to the linear equation y1 = 43.75x1 + 725; where x1 represents the temperature difference and y1 represents the speed of the high-temperature variable frequency fan; temperature difference = condenser temperature - ambient temperature. Step 1.2: When both compressors are in the start-up state, the low-temperature stage variable frequency fan operates under the following conditions: The low-temperature storage cabinet monitors the ambient temperature in real time; When the ambient temperature is ≥ H2, where H2 = B - 5℃, and B is the ambient temperature when the "Ambient Temperature Too High" indicator light starts to illuminate, the low-temperature variable frequency fan enters high-speed mode at the highest speed N3. When the ambient temperature is ≤ H1, where H1 = H2 - 10, the low-temperature stage variable frequency fan enters the low-speed mode at the lowest speed N1. When H1 < ambient temperature < H2, the low-temperature variable frequency fan rotates according to the linear equation y2 = 70x2 - 500, entering the variable speed mode; where x2 represents the ambient temperature and y2 represents the speed of the low-temperature variable frequency fan. Step 1.3: When both compressors of the low-temperature storage cabinet are stopped, the two variable frequency fans, namely the high-temperature stage variable frequency fan and the low-temperature stage variable frequency fan, operate simultaneously under the following conditions: The low-temperature storage cabinet monitors the ambient temperature in real time. When the ambient temperature is ≤H3, where H3 = H1 - 8℃, the two variable frequency fans enter the stop mode. When the ambient temperature H3 < ambient temperature ≤ H1, the two variable frequency fans enter the low-speed mode at the lowest speed N1. When the ambient temperature H1 < ambient temperature < H2, the two variable frequency fans rotate at different speeds according to the linear equation y3 = 20x3 + 500, entering the variable speed mode; where x3 represents the ambient temperature and y3 represents the speed of the two variable frequency fans. When the ambient temperature is ≥ H2, the two variable frequency fans enter high-speed mode at the highest speed N2. Step 2: Dust removal mode; The low-temperature storage cabinet monitors the status of the variable frequency fan and compressor in real time. Every month, when the two compressors stop rotating, after a 30-second delay, the two variable frequency fans automatically enter the reverse control mode and run in reverse at the highest speed N2 for 3 minutes. During the reverse process, when the temperature inside the low-temperature storage cabinet is higher than the set temperature of -0.2℃, the two variable frequency fans stop reversing.

2. The control method of the variable frequency fan of the cryopreservation cabinet according to claim 1, characterized in that: High-speed mode is the mode that runs at a constant speed at the highest speed; low-speed mode is the mode that runs at a constant speed at the lowest speed; variable speed mode is the mode that runs at varying speeds according to the linear equation y=kx+b. The reverse control mode is a mode in which the variable frequency fan rotates in the opposite direction to its original rotation direction.

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