WO2020042590A1 - Heating control method for chassis of outdoor unit of air conditioner - Google Patents

Abstract

Disclosed is a heating control method for a chassis of an outdoor unit of an air conditioner. The method comprises: after defrosting is completed and a de-icing device is switched off, detecting whether there is water, ice or a mixture of ice and water in a recess of a chassis; if ice or the mixture of ice and water is present in the recess, restarting the de-icing device, and after the de-icing device is restarted and runs for a first set period of time, re-detecting whether there is water, ice or the mixture of ice and water in the recess of the chassis; if there is water and no ice in the recess, after a second set period of time, re-detecting whether there is water, ice or the mixture of ice and water in the recess of the chassis; if there is no water, ice or the mixture of ice and water in the recess, detecting whether a difference value between the temperature of the de-icing device and the outdoor ambient temperature is greater than a set difference value; and if so, controlling the de-icing device to be powered off. The de-icing effect of the de-icing device is determined by detecting whether there is water, ice or a mixture of ice and water in a recess of a chassis, thereby maximally ensuring the effectiveness of the de-icing device and preventing the chassis from accumulating water and being frozen.

Description

Method for controlling heating of air conditioner outdoor unit chassis Technical field

The invention belongs to the technical field of air conditioning, and in particular relates to a method for controlling heating of an air conditioner outdoor unit chassis.

Background technique

The low temperature air source heat pump is mainly suitable for the heating season in the severe cold winter. The outdoor unit chassis after defrosting will store part of the water.

technical problem

If this water is not discharged in time, it will cause ice blockage in the chassis, resulting in the failure to discharge the water after subsequent defrosting, and icing in the chassis, resulting in poor defrosting effect, affecting the normal operation of the heat exchanger and reducing heat exchange efficiency.

Technical solutions

The invention provides a method for controlling the heating of the chassis of an outdoor unit of an air conditioner to prevent the chassis from freezing.

In order to solve the above technical problems, the present invention is implemented using the following technical solutions:

An air conditioning outdoor unit chassis heating control method, which has a groove on the chassis, a drainage hole is opened at the bottom of the groove, and an ice melting device is provided in the groove for heating the chassis;

The control method includes:

When the defrosting of the air conditioner starts, start the ice melting device; after the defrost ends, turn off the ice melting device, and then perform the following steps:

(1) Check whether there is water, ice, or ice-water mixture in the groove of the chassis;

If there is ice or ice-water mixture in the groove, perform step (2): restart the ice-melting device, and after running for the first set time period, return to step (1);

If there is water or ice in the groove, after the second set time period, return to step (1);

If there is no water, ice, and ice-water mixture in the groove, perform step (3): check whether the difference between the temperature of the ice melting device and the outdoor ambient temperature is greater than the set difference; if so, control the ice melting device to power off.

Further, after controlling the power-off of the ice-melting device, the method further includes: after the power-off of the ice-melting device is controlled for a third set period of time, re-detecting whether the difference between the temperature of the ice-melting device and the outdoor ambient temperature is greater than a set value Difference; if yes, control the air conditioner to power off.

Furthermore, during the air-conditioning heating operation, if the defrost conditions are met, the four-way valve is reversed, and the defrost starts, and the ice melting device is started; after the defrost is completed, the four-way valve is reversed again, and the ice melting device continues to operate. After setting the time period, turn off the ice melting device, and then perform step (1).

Furthermore, a range of the set difference is 4 ° C to 8 ° C.

Further, the tension signal in the groove is detected by the tension detection device, and it is determined whether there is water, ice, or an ice-water mixture in the groove according to the detected tension signal.

Still further, the tension detection device is provided with multiple, each of which detects tension signals at multiple positions in the groove; each tension detection device separately determines whether there is water, ice, or an ice-water mixture in the groove, and judges The results are sent to the air-conditioning control board;

The air-conditioning control board determines whether the determination result of the tension detection device is ice or ice-water mixture;

If yes, the air conditioning control board determines that there is ice or ice-water mixture in the groove;

If not, the air-conditioning control board determines whether there is a tension detection device and the result of the determination is whether there is water or ice;

If it is, the air conditioning control board determines whether there is water or ice in the groove; if not, the air conditioning control board determines that there is no water or ice in the groove.

Further, the density signal in the groove is detected by the density sensor, and it is determined whether there is water, ice, or an ice-water mixture in the groove according to the detected density signal.

Still further, a plurality of density sensors are provided to detect density signals at multiple positions in the groove; each density sensor determines whether there is water, ice, or an ice-water mixture in the groove, and sends the determination result. To the air conditioning control board;

The air-conditioning control board determines whether the density sensor determines that the result is ice or an ice-water mixture;

If yes, the air conditioning control board determines that there is ice or ice-water mixture in the groove;

If not, the air-conditioning control board determines whether there is a density sensor and the result is water or ice;

If it is, the air conditioning control board determines whether there is water or ice in the groove; if not, the air conditioning control board determines that there is no water or ice in the groove.

Further, the specific heat capacity signal in the groove is detected by the specific heat capacity detection device, and it is determined whether there is water, ice, or an ice-water mixture in the groove according to the detected specific heat capacity signal.

Still further, the specific heat capacity detection device is provided with a plurality of specific heat capacity signals for detecting multiple positions in the groove; each specific heat capacity detection device determines whether there is water, ice, or an ice-water mixture in the groove, and judges The results are sent to the air-conditioning control board;

The air-conditioning control board determines whether the specific heat capacity detection device has ice or ice-water mixture;

If yes, the air conditioning control board determines that there is ice or ice-water mixture in the groove;

If not, the air-conditioning control board judges whether there is water or ice in the judgment result of the specific heat capacity detection device;

If it is, the air conditioning control board determines whether there is water or ice in the groove; if not, the air conditioning control board determines that there is no water or ice in the groove.

Beneficial effect

Compared with the prior art, the advantages and positive effects of the present invention are: The method for controlling the heating of the chassis of an air conditioner outdoor unit of the present invention detects whether water, ice, Ice-water mixture; if there is ice or ice-water mixture in the groove, restart the ice-melting device. After the ice-melting device restarts for the first set period of time, re-check whether there is water, ice, Ice-water mixture; if there is water or ice in the groove, after the second set period of time, re-check whether there is water, ice, or ice-water mixture in the groove of the chassis; if there is no water, ice, or ice in the groove Water mixture, it is detected whether the difference between the temperature of the ice melting device and the outdoor environment temperature is greater than a set difference; if so, the ice melting device is controlled to be powered off; therefore, when the defrost starts, the ice melting device is started and heated Chassis, after the defrost is completed, close the ice melting device, and then check the ice melting effect of the ice melting device by detecting whether there is water, ice, and ice-water mixture in the groove of the chassis to ensure the maximum degree of ice melting. The effectiveness of the ice device, to avoid freezing water in the chassis to improve the efficiency of air-conditioning heat at a low temperature conditions, thereby increasing the defrosting effect.

After reading the detailed description of the embodiments of the present invention with reference to the accompanying drawings, other features and advantages of the present invention will become more clear.

BRIEF DESCRIPTION OF THE DRAWINGS

1 is a flowchart of an embodiment of a heating control method for an air-conditioning outdoor unit chassis according to the present invention;

FIG. 2 is a schematic structural diagram of the chassis in FIG. 1.

Reference signs:

1. Chassis; 1-1, groove; 1-2, drainage hole; 1-3, first mounting position; 1-4, second mounting position;

2. Ice melting device.

Embodiments of the invention

The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

Aiming at the problem that the air conditioner outdoor unit chassis easily freezes and affects the defrosting effect, this embodiment proposes a heating control method for the air conditioner outdoor unit chassis to improve the defrosting effect. Hereinafter, the method for controlling the heating of the air-conditioning outdoor unit chassis of this embodiment will be described in detail.

The air conditioner includes an air conditioner indoor unit and an air conditioner outdoor unit, and the air conditioner indoor unit and the air conditioner outdoor unit are connected. The outdoor unit of the air conditioner includes a condenser and a chassis 1. The chassis 1 has a groove 1-1 to form a water storage area. A plurality of drainage holes 1-2 are provided at the bottom of the groove in the groove 1-1. An ice melting device 2 is provided in the -1 for heating the chassis. The condenser is placed above the groove 1-1, and the water droplets formed by the defrost on the surface of the condenser fall into the groove 1-1 and are discharged through the drainage hole 1-2, as shown in FIG. 2.

During the air-conditioning heating process, when the defrost conditions are met, the four-way valve is reversed and defrost is started. The high-temperature refrigerant discharged from the compressor enters the condenser through the four-way valve. The condenser temperature rises and the frost on the surface of the condenser begins to melt. It is formed into water, drips into the groove 1-1 of the chassis 1, and is discharged through the drainage hole 1-2. When the defrost is over, the four-way valve is reversed again, and the air conditioner operates normally.

In the heating control method for the chassis of the outdoor unit of the air conditioner of this embodiment, when the defrost of the air conditioner starts, the four-way valve is switched to start the ice melting device to heat the chassis 1. After the defrost is completed, the four-way valve is switched again to close the ice melting Device, after closing the ice melting device, perform the following steps, as shown in FIG. 1.

Step S1: detecting whether there is water, ice, or ice-water mixture in the groove of the chassis.

Due to the low outdoor ambient temperature, water dripping from the surface of the condenser into the groove of the chassis may condense into ice and block the drainage holes. Therefore, after the defrost is completed, it is necessary to detect whether there is water, ice, or ice in the groove of the chassis Water mixture.

S11: If there is ice or ice-water mixture in the groove, go to step S2: restart the ice-melting device. After the ice-melting device restarts for the first set time period, return to step S1. In this embodiment, the first set time period is 30 minutes, which avoids that the ice is not completely melted when the time is too short, and avoids waste of power if the time is too long.

S12: If there is water or ice in the groove, after detecting the second set time period of water or ice in the groove, return to step S1. If there is no ice in the groove, the water in the groove may be drained through the drainage hole and not yet drained. Therefore, after the second set time period, return to S1. In this embodiment, the second set time period is 20 minutes, which avoids that the time is too short and the water is not discharged in time and is re-detected, which makes the control tedious, and avoids that the time is too long and the entire control logic is time-consuming.

S13: If there is no water, ice, or ice-water mixture in the groove, step S3 is performed.

Step S3: Obtain the temperature of the ice melting device and the outdoor ambient temperature, and calculate the difference between the two.

Step S4: It is determined whether the difference is greater than a set difference.

If yes, it means that the temperature difference between the ice melting device and the outdoor ambient temperature is large, the ice melting device is not powered off, the ice melting device is still heating the chassis, and there is no water or ice in the chassis, the chassis is dry burned, and power is wasted, then step S5 is performed. : Control the power cut of the ice-melting device to avoid wasting electricity and accidents.

The ice melting device is directly powered by the air conditioning power board. If the air conditioning power board is powered off, the ice melting device is powered off. A normally open contact of the relay K is connected in series on the power supply line of the air conditioning power board and the ice melting device, and the air conditioning control board controls whether the coil of the relay K is powered on or not. The coil of the air conditioning control board controls the relay to power on, the normally open contact of the relay is closed, and the ice melting device is powered on; the coil of the air conditioning control board controls the relay to power off, the normally open contact of the relay is open, and the ice melting device is powered off .

In this embodiment, to control the power-off of the ice-melting device, the relay coil may be controlled to be powered on first, and then the coil may be controlled to be powered-off to avoid the power-off failure of the ice-melting device due to a relay failure.

In the method for controlling the heating of the chassis of the outdoor unit of the air conditioner of this embodiment, after the defrosting is completed and the ice melting device is turned off, it is detected whether there is water, ice, or an ice-water mixture in the groove of the chassis; Then restart the ice-melting device. After the ice-melting device restarts for the first set period of time, re-check whether there is water, ice, and ice-water mixture in the groove of the chassis; if there is no ice in the groove, After the second set period of time, re-check whether there is water, ice, or ice-water mixture in the groove of the chassis; if there is no water, ice, or ice-water mixture in the groove, check the temperature of the ice-melting device and the outdoor ambient temperature. Whether the difference is greater than the set difference; if it is, the ice melting device is controlled to be powered off; therefore, in the control method of this embodiment, when the defrost starts, the ice melting device is started, the chassis is heated, and after the defrost is completed, the melting is closed. Ice device, and then detect the ice melting effect of the ice melting device by detecting whether there is water, ice, and ice-water mixture in the groove of the chassis, to ensure the effectiveness of the ice melting device to the greatest extent, and avoid the chassis Water freezes, to improve the efficiency of the air conditioning heat at a low temperature conditions, thereby increasing the defrosting effect.

In this embodiment, by adding a chassis ice-melting device and controlling it, the water generated after defrosting in the chassis can be effectively discharged to ensure that the water in the chassis does not freeze and does not cause ice blocking. At the same time, through multiple controls, the reliability of the chassis ice-melting device is ensured, electrical energy is wasted, risks of electricity consumption that may be caused are avoided, and the service life of the chassis ice-melting device is extended.

After the ice-melting device is controlled to be powered off, the control method further includes the following steps, as shown in FIG. 1.

Step S6: After controlling the ice-melting device to power off for a third set period of time, re-obtain the temperature of the ice-melting device and the outdoor ambient temperature, and calculate the difference between the two.

Step S7: Determine whether the difference is greater than a set difference.

If yes, it means that the ice-melting device is faulty or not powered off, or the air conditioner may also fail, then execute step S8: control the air conditioner to power off. After the power supply board of the air conditioner is powered off, the ice melting device is forced to be powered off to ensure the safety of the air conditioner and the ice melting device, thereby effectively avoiding the problem of internal parts being damaged due to the normal power failure of the ice melting device.

The power cut and control protection of the ice melting device are twofold. The first is the use of relays for power cut control, and the second is the forced power cut through the air conditioner. This embodiment controls and protects the start-stop of the ice-melting device, to the greatest extent, avoiding the impact of the wrong power-on or unpowered ice-melting device on other components of the air-conditioning unit.

In this embodiment, the range of the difference value is set to 4 ° C to 8 ° C. Within this range of values, it is possible to avoid the power failure of the ice melting device caused by the value being too small, and the value of the value to be too large. The ice melting device is overheated and an electricity accident occurs; therefore, within this value range, not only the normal power supply of the ice melting device is guaranteed, but also the chassis is prevented from burning dry and wasting electricity.

In this embodiment, the third set time period is 3 minutes, which avoids the occurrence of power consumption accidents caused by too long time, and avoids frequent control caused by too short time and affects the normal operation of the ice melting device and air conditioner.

During the air-conditioning heating operation, if the defrost conditions are met, the four-way valve is reversed. When the defrost starts, the ice melting device is started to heat the chassis to prevent the chassis from freezing. After the defrost is completed, the four-way valve is reversed again and melted. After the ice device continues to run for a set period of time, the ice melting device is closed again to prevent the water dripping into the chassis from freezing, to prevent the water from freezing again, and wasting electricity, and then step S1 is performed.

The ice melting device is an electric heating device, such as an electric heating tube, a resistor, and an electric heating belt. The precise control can maximize the energy utilization rate and make the unit more energy efficient. Of course, the ice melting device can also use other energy to convert into thermal energy, and is not limited to electrical energy.

In this embodiment, since the tension of the water, ice, and ice-water mixture is different, it can be determined by the tension detection whether the water, ice, or ice-water mixture is in the groove. The tension detection device detects the tension signal in the groove, and determines whether there is water, ice, or an ice-water mixture in the groove according to the detected tension signal; the detection method is simple and the judgment result is accurate.

E.g,

The detected tension signal is within the first set tension range, and the groove is ice or ice-water mixture;

The detected tension signal is within the second set tension range, then there is water and ice in the groove;

The detected tension signal is within the third set tension range, and the groove is a water-free, ice-free, and ice-free water mixture.

In this embodiment, a plurality of tension detection devices are provided, and the tension signals at multiple positions in the groove are respectively detected and sent to the air-conditioning control board. For example, the ice melting device is installed in the groove 1-1, and a tension detecting device is respectively arranged at the front section, the middle section and the rear section of the ice melting device in the groove 1-1, that is, the three first installations of the ice melting device Install a tension detection device at positions 1-3. In addition, one tension detection device is arranged at three positions in the groove away from the ice melting device, that is, at three second installation positions 1-4. That is, a total of six tension detection devices are arranged in the groove.

The detection process is:

(A) Each tension detection device judges whether there is water, ice, or ice-water mixture in the groove, and sends the judgment result to the air-conditioning control board.

(B) The air conditioner control board determines whether a tension detection device has a judgment result of ice or ice-water mixture.

If yes, that is, at least one tension detecting device detects ice or ice-water mixture in the groove, the air-conditioning control board finally determines that ice or ice-water mixture is in the groove, and executes S11.

If not, that is, all the tension detecting devices have not detected ice or ice-water mixture in the groove; then the air conditioning control board determines whether there is water or ice without the determination result of the tension detecting device.

If yes, that is, at least one tension detecting device detects that there is water or ice in the groove, the air conditioning control board finally determines that there is water or ice in the groove, and executes S12.

If not, the air-conditioning control board determines that there is no water or ice in the groove, and there is no ice-water mixture, that is, step S13 is performed.

According to the above detection process, as long as any tension detecting device detects ice or ice-water mixture, the air-conditioning control board determines that there is ice or ice-water mixture in the groove, and executes step S11 to restart the ice-melting device to minimize the chassis. Freeze. When none of the tension detection devices detects ice or ice-water mixture in the groove, as long as any tension detection device detects water or ice in the groove, the air conditioning control board determines that there is water or ice in the groove. Go to step S12. When none of the tension detecting devices detects that there is water, ice, or ice-water mixture in the groove, the air-conditioning control board determines that there is no water, ice, or ice-water mixture in the groove, and executes step S13.

As another preferred design solution of this embodiment, since the density of water, ice, and ice-water mixture is different, it can be determined by density detection whether water, ice or ice-water mixture is in the groove. In this embodiment, the density signal in the groove is detected by the density sensor, and it is determined whether there is water, ice, or an ice-water mixture in the groove according to the detected density signal; the detection method is simple and the judgment result is accurate.

E.g,

The detected density signal is within the first set density range, and the groove is ice or ice-water mixture;

The detected density signal is within the second set density range, then the groove is water-free or ice-free;

The detected density signal is within a third set density range, and the groove is a water-free, ice-free, and ice-free water mixture.

In this embodiment, a plurality of density sensors are provided, which respectively detect tension signals at a plurality of positions in the groove and send the signals to the air-conditioning control board. For example, the ice melting device is installed in the groove 1-1, and a density sensor is respectively arranged at the front section, the middle section and the rear section of the ice melting device in the groove 1-1, that is, the three first installation positions of the groove Install a density sensor at 1-3. In addition, one density sensor is arranged at three positions in the groove away from the ice melting device, that is, at three second installation positions 1-4. That is, a total of six density sensors are arranged in the groove.

The detection process is:

(C) Each density sensor judges whether there is water, ice, or ice-water mixture in the groove, and sends the judgment result to the air-conditioning control board.

(D) The air conditioner control board determines whether the density sensor has a judgment result of ice or ice-water mixture.

If yes, that is, at least one density sensor detects ice or ice-water mixture in the groove, the air-conditioning control board finally determines that ice or ice-water mixture is in the groove, and executes S11.

If not, that is, all density sensors have not detected ice or ice-water mixture in the groove; then the air-conditioning control board determines whether there is a density sensor to determine whether there is water or ice.

If yes, that is, at least one density sensor detects that there is water or ice in the groove, the air conditioning control board finally determines that there is water or ice in the groove, and executes S12.

If not, the air-conditioning control board determines that there is no water or ice in the groove, and there is no ice-water mixture, that is, step S13 is performed.

According to the above detection process, as long as any density sensor detects ice or ice-water mixture, the air-conditioning control board determines that there is ice or ice-water mixture in the groove, executes step S11, restarts the ice-melting device, and minimizes chassis freezing. ice. When no density sensor detects ice or ice-water mixture in the groove, as long as any density sensor detects water or ice in the groove, the air-conditioning control board determines that there is water or ice in the groove, and performs steps S12. When all the density sensors do not detect that there is water, ice, or ice-water mixture in the groove, the density sensor judges that there is no water, ice, or ice-water mixture in the groove, and step S13 is performed.

As another preferred design solution of this embodiment, since the specific heat capacity of water, ice, and ice-water mixture is different, it can be determined whether the groove is water, ice, or ice-water mixture through specific heat capacity detection. In this embodiment, the specific heat capacity signal in the groove is detected by the specific heat capacity detection device, and whether there is water, ice, or an ice-water mixture in the groove is determined based on the detected specific heat capacity signal; the detection method is simple and the judgment result is accurate.

E.g,

The detected specific heat capacity signal is within the first set specific heat capacity range, and the groove is ice or an ice-water mixture;

The detected specific heat capacity signal is within the second set specific heat capacity range, and there is water and ice in the groove;

The detected specific heat capacity signal is within the third set specific heat capacity range, and the groove is a water-free, ice-free, and ice-free water mixture.

In this embodiment, a plurality of specific heat capacity detection devices are provided, which respectively detect specific heat capacity signals at multiple positions in the groove, and send the specific heat capacity signals to the air conditioning control board. For example, the ice melting device is installed in the groove 1-1, and a specific heat capacity detection device is respectively arranged at the front section, the middle section and the rear section of the ice melting device in the groove 1-1, that is, three first installations of the ice melting device are installed in the groove. Install a specific heat capacity detection device at positions 1-3. In addition, one specific heat capacity detection device is arranged at three positions in the groove away from the ice melting device, that is, at three second installation positions 1-4. That is, six specific heat capacity detection devices are arranged in the groove.

The detection process is:

(E) Each specific heat capacity detection device determines whether there is water, ice, or an ice-water mixture in the groove, and sends the determination result to the air-conditioning control board.

(F) The air-conditioning control board determines whether the specific heat capacity detection device has ice or an ice-water mixture.

If yes, that is, at least one specific heat capacity detecting device detects ice or ice-water mixture in the groove, the air-conditioning control board finally determines that ice or ice-water mixture is in the groove, and executes S11.

If not, that is, all the specific heat capacity detection devices have not detected ice or ice-water mixture in the groove; then the air-conditioning control board judges whether the specific heat capacity detection device has water and no ice.

If yes, that is, at least one specific heat capacity detecting device detects that there is water or ice in the groove, the air conditioning control board finally determines that there is water or ice in the groove, and executes S12.

If not, the air-conditioning control board determines that there is no water or ice in the groove, and there is no ice-water mixture, that is, step S13 is performed.

According to the above detection process, as long as any specific heat capacity detection device detects ice or ice-water mixture, the air-conditioning control board determines that there is ice or ice-water mixture in the groove, executes step S11, restarts the ice-melting device, and minimizes the chassis Freeze. When none of the specific heat capacity detection devices detects ice or ice-water mixture in the groove, as long as any specific heat capacity detection device detects water or ice in the groove, the air conditioning control board determines that there is water or ice in the groove. Go to step S12. When none of the specific heat capacity detecting devices detects that there is water, ice, or ice-water mixture in the groove, the air-conditioning control board determines that there is no water, no ice, or ice-water mixture in the groove, and executes step S13.

Of course, the above description is not a limitation on the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also belong to The protection scope of the present invention.

Claims (10)

1. A method for controlling the heating of an outdoor unit chassis of an air conditioner, which is characterized in that: a groove is provided on the chassis, a drainage hole is opened at the bottom of the groove, and an ice melting device is provided in the groove for Heated chassis

   The control method includes:

   When the defrosting of the air conditioner starts, start the ice melting device; after the defrost ends, turn off the ice melting device, and then perform the following steps:

   (1) Check whether there is water, ice, or ice-water mixture in the groove of the chassis;

   If there is ice or ice-water mixture in the groove, perform step (2): restart the ice-melting device, and after running for the first set time period, return to step (1);

   If there is water or ice in the groove, after the second set time period, return to step (1);

   If there is no water, ice, and ice-water mixture in the groove, perform step (3): check whether the difference between the temperature of the ice melting device and the outdoor ambient temperature is greater than the set difference; if so, control the ice melting device to power off.
2. The control method according to claim 1, wherein after controlling the power-off of the ice melting device, the method further comprises:

   After controlling the ice-melting device to power off for a third set period of time, it is re-tested whether the difference between the temperature of the ice-melting device and the outdoor ambient temperature is greater than the set difference; if so, the air conditioner is controlled to power off.
3. The control method according to claim 1, characterized in that: during the air-conditioning heating operation, if the defrost condition is satisfied, the four-way valve is switched, defrost starts, and the ice melting device is started; after the defrost is completed, the four-way The valve is reversed again, and after the ice melting device continues to run for a set period of time, the ice melting device is turned off, and then step (1) is performed.
4. The control method according to claim 1, wherein the range of the setting difference is 4 ° C to 8 ° C.
5. The control method according to claim 1, characterized in that the tension signal in the groove is detected by the tension detection device, and it is determined whether there is water, ice, or an ice-water mixture in the groove according to the detected tension signal.
6. The control method according to claim 5, characterized in that:

   The tension detecting device is provided with a plurality of, which respectively detect tension signals at multiple positions in the groove;

   Each tension detecting device judges whether there is water, ice, or ice-water mixture in the groove, and sends the judgment result to the air-conditioning control board;

   The air-conditioning control board determines whether the determination result of the tension detection device is ice or ice-water mixture;

   If yes, the air conditioning control board determines that there is ice or ice-water mixture in the groove;

   If not, the air-conditioning control board determines whether there is a tension detection device and the result of the determination is whether there is water or ice;

   If it is, the air conditioning control board determines whether there is water or ice in the groove; if not, the air conditioning control board determines that there is no water or ice in the groove.
7. The control method according to claim 1, wherein a density signal in the groove is detected by a density sensor, and whether there is water, ice, or an ice-water mixture in the groove is determined based on the detected density signal.
8. The control method according to claim 7, characterized in that:

   A plurality of density sensors are provided to detect density signals at multiple positions in the groove respectively;

   Each density sensor judges whether there is water, ice, or ice-water mixture in the groove, and sends the judgment result to the air-conditioning control board;

   The air-conditioning control board determines whether the density sensor determines that the result is ice or an ice-water mixture;

   If yes, the air conditioning control board determines that there is ice or ice-water mixture in the groove;

   If not, the air-conditioning control board determines whether there is a density sensor and the result is water or ice;

   If it is, the air conditioning control board determines whether there is water or ice in the groove; if not, the air conditioning control board determines that there is no water or ice in the groove.
9. The control method according to claim 1, wherein a specific heat capacity signal in the groove is detected by a specific heat capacity detection device, and whether there is water, ice, or an ice-water mixture in the groove is determined based on the detected specific heat capacity signal.
10. The control method according to claim 9, characterized in that:

    A plurality of specific heat capacity detection devices are provided, which respectively detect specific heat capacity signals at multiple positions in the groove;

    Each specific heat capacity detection device determines whether there is water, ice, or an ice-water mixture in the groove, and sends the judgment result to the air-conditioning control board;

    The air-conditioning control board determines whether the specific heat capacity detection device has ice or ice-water mixture;

    If yes, the air conditioning control board determines that there is ice or ice-water mixture in the groove;

    If not, the air-conditioning control board judges whether there is water or ice in the judgment result of the specific heat capacity detection device;

    If it is, the air conditioning control board determines whether there is water or ice in the groove; if not, the air conditioning control board determines that there is no water or ice in the groove.