Self-cleaning method of heat exchanger and air conditioner

Abstract

The invention relates to a self-cleaning method of an air conditioner, in particular to a self-cleaning method of a heat exchanger and the air conditioner. In the first stage, the dew point temperature is increased to be higher than the freezing point; in the second stage, the indoor unit is started, so that the surface of the heat exchanger is condensed and frosted; in the third stage, a frost layer on the surface of the heat exchanger is melted, in the first stage, the heat exchanger of the indoor unit is in a heating mode, a draught fan is started, in the first stage, a humidification module is started, the indoor unit further comprises a humidity sensing module, and the control system dynamically adjusts the heating power and the humidification intensity according to the dew point temperature provided by the humidity sensing module. When the refrigeration mode is started, the dew point is larger than 0 DEG C, and a fan of the indoor unit is started; through the mode of increasing the temperature and the humidity, the dew point temperature is increased, the condensation amount is increased, the condensation time is prolonged, condensed water can fully permeate into an ash layer, the water amount during defrosting is increased, and the cleaning effect is improved.

Description

Technical Field

[0001] The invention relates to a self-cleaning method for an air conditioner, and in particular to a self-cleaning method for a heat exchanger and an air conditioner. Background Art

[0002] The evaporator is a part of the heat exchange component of the air conditioner. The refrigerant absorbs heat in the evaporator and changes from liquid to gas. The temperature of the evaporator's heat dissipation fins is relatively low compared to the surrounding area, and there is often condensed water on the surface of the heat dissipation fins. Therefore, the evaporator often operates in a wet state. When the dust-laden airflow passes through the surface of the evaporator's fins, the dust layer will stick to the fins and form a shell, resulting in reduced thermal conductivity of the evaporator fins.

[0003] In the prior art (CN1702406A), the evaporator surface is first frosted and then defrosted to allow dust and dirt to flow away with the frost water to clean the evaporator fins.

[0004] In the existing disclosure (CN107166670A), condensed water is made to flow on the fins by frosting and defrosting twice, thereby increasing the cleaning effect;

[0005] However, the above scheme does not take into account the situation of low temperature and humidity. In winter, when the evaporator is working, the temperature difference between the inside and outside is small and the air humidity is low, resulting in a low dew point temperature. The difference between the dew point temperature and the freezing point temperature is small, and the condensed water will freeze quickly to form a frost layer that cannot flow. In addition, the generated condensed water is small and cannot completely soak the ash layer. In addition, during the defrosting process, the amount of water used for flushing is small, which will affect the cleaning efficiency and effect. Summary of the invention

[0006] One of the purposes of the present invention is to provide a self-cleaning method for a heat exchanger and an air conditioner, so as to improve the cleaning efficiency and effect of an evaporator when the temperature and humidity are low.

[0007] A self-cleaning method for a heat exchanger, comprising three stages;

[0008] In the first stage, the dew point temperature is increased so that the dew point temperature is above the freezing point;

[0009] In the second stage, the indoor unit is turned on to cause condensation and frost to form on the surface of the heat exchanger;

[0010] In the third stage, the frost layer on the surface of the heat exchanger is melted.

[0011] Furthermore, in the first stage, the indoor unit heat exchanger is in heating mode, and the fan is turned on.

[0012] Furthermore, the humidification module is turned on in the first stage.

[0013] Furthermore, the indoor unit also includes a humidity sensor module, and the control system dynamically adjusts the heating power and the humidification intensity according to the dew point temperature provided by the humidity sensor module.

[0014] Furthermore, when the cooling mode is turned on, the dew point is greater than 0°C and the fan of the indoor unit is turned on.

[0015] Furthermore, the indoor unit also includes a fresh air module, and the first stage also includes three steps:

[0016] S1, turn on the refrigeration function to make the evaporator surface frosted;

[0017] S2, turn on the heating function to melt the frost on the evaporator surface, forming water droplets, which are stored in the indoor unit;

[0018] S3, turn on the fresh air function to exhaust the dry air in the room and bring in the wet air from the outside.

[0019] Furthermore, in S2, the fan of the indoor unit is not turned on.

[0020] Furthermore, the moisture in the indoor unit in S3 is introduced into the fresh air outlet.

[0021] A second object of the present invention is to provide an air conditioner for executing the above method.

[0022] Furthermore, it also includes a fresh air system.

[0023] The beneficial effects achieved by the present invention using the above structure are as follows:

[0024] By increasing the temperature and humidity, the dew point temperature is increased, the condensation amount is increased, and the condensation time is prolonged, so that the condensed water can fully penetrate into the ash layer, increase the amount of water during defrosting, and improve the cleaning effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is the dew point temperature comparison table;

[0026] Figure 2 This is a comparison table of saturated water vapor pressure and temperature. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0028] It should be noted that the words "front", "rear", "left", "right", "up" and "down" used in the following description refer to directions in the accompanying drawings, and the words "inside" and "outside" refer to directions toward or away from the geometric center of a specific component, respectively.

[0029] In order to make the contents of the present invention more clearly understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0030] The present invention proposes a self-cleaning method for a heat exchanger, which has three stages. In the first stage, the indoor temperature is increased to increase the amount of saturated water vapor in the air, and at the same time, the water vapor content in the air is increased to increase the absolute humidity;

[0031] Preferably, increasing relative humidity;

[0032] The higher the relative humidity of the air, the closer the water vapor in the air is to saturation, the closer the dew point temperature is to the current temperature, and the easier it is for condensation to form on the evaporator surface. For example:

[0033] Assumption 1: When the temperature is 20℃ and the relative humidity of indoor air is 30%,

[0034] The saturated water vapor content of air at 20°C is 17.3 g / m 3 At this time, the actual water vapor content in the air is 17.3g / m 3 *30% = 5.19 g / m 3 ;

[0035] Assumption 2: When the temperature is 20℃ and the relative humidity of the indoor air is 50%,

[0036] The saturated water vapor content of the air remains unchanged. At this time, the actual water vapor content is 17.3×0.5=8.65g / m 3 ;

[0037] You can find it in the table.

[0038] For 5.19g / m 3 , the corresponding dew point is about 7℃;

[0039] For 8.65g / m 3 , the corresponding dew point is about 10℃;

[0040] The above results show that the higher the relative humidity, the closer the dew point temperature is to the current temperature.

[0041] Preferably, increasing the temperature;

[0042] The dew point temperature is not only affected by relative humidity, but also by temperature. The above example shows that the higher the relative humidity, the higher the dew point temperature. In fact, the higher the temperature, the greater the amount of saturated water vapor in the air, and the more difficult it is to reach saturation, which will also lead to an increase in the dew point temperature. For example:

[0043] Assumption 3: At 10℃ and relative humidity 50%,

[0044] According to the table, the saturated water vapor content of air is about 9.4g / m 3 ;

[0045] According to the calculation formula of relative humidity, the actual water content at this time is 4.7g / m 3 , according to the table, the saturated water vapor pressure at 10℃ is about 1.228kPa;

[0046] At this time, to condense the water vapor, the temperature needs to be lowered so that the relative humidity reaches 100%. At this time, the relative humidity is 50%, so the saturated water vapor pressure needs to be reduced by half to 0.614 kpa;

[0047] From the common saturated water vapor pressure and temperature comparison table, we can know that

[0048] The saturated water vapor pressure is 0.614 kPa and the corresponding temperature is about 0°C.

[0049] Assumption 4, at 20℃, relative humidity 50%.

[0050] According to the table, the saturated water vapor content of air is about 17.3g / m 3 ;

[0051] According to the calculation formula of relative humidity, the actual water content at this time is 8.65g / m 3 , according to the table, the saturated water vapor pressure at 20℃ is about 2.3346kPa;

[0052] At this time, to make the relative humidity reach 100%, it is also necessary to reduce the saturated water vapor pressure by half to 1.1673 kPa;

[0053] From the common saturated water vapor pressure and temperature comparison table, we can know that

[0054] The saturated water vapor pressure is 1.1673 kPa and the corresponding temperature is about 10°C.

[0055] The above results show that the higher the temperature, the higher the dew point temperature will be when the relative humidity is the same.

[0056] Therefore, combined with the above, increasing the temperature and absolute humidity in the first stage will inevitably lead to an increase in the dew point temperature.

[0057] In addition, as the dew point temperature rises, the absolute humidity in the air increases, which means an increase in the water vapor content in the air. It also means that after reaching the dew point, the evaporator continues to absorb heat, and the saturated vapor pressure continues to decrease as the indoor temperature drops, and more condensed water will be generated on the evaporator surface.

[0058] In combination with the above, in the first stage, the heating mode of the air conditioner needs to be started;

[0059] Raise the indoor temperature to increase the saturated vapor pressure. If the air conditioner has a humidification function, start the humidification at the same time. You can also combine with an independent humidifier to humidify the indoor air.

[0060] In addition, if the evaporator originally operates in a wet environment, it will become a condenser in the heating mode, continuously dissipating heat. The condensed water on the surface of the fins will evaporate, making the dust on its surface looser. When the evaporator is cooled again, the loose ash layer has an enhanced water absorption capacity, and more condensed water will be used to clean the fin surface during the subsequent flushing process.

[0061] The air conditioner should be equipped with temperature and humidity sensors, and the control system should dynamically adjust the heating power and humidification intensity according to the target dew point temperature.

[0062] According to the above content, the following embodiment 1 is obtained, when the temperature is greater than 10°C and the relative humidity of the indoor air is less than 30%:

[0063] Stage 1: Raise the dew point temperature to make it higher than the freezing point;

[0064] Start heating mode: When the air conditioning system detects that the indoor temperature is greater than 10°C and the relative humidity is less than 30%, it automatically switches to heating mode.

[0065] Heating and humidification:

[0066] Increase indoor temperature: The heating function can raise the indoor temperature to 11-20℃ and increase the amount of saturated water vapor in the air.

[0067] Start the humidification function: If the air conditioner has a humidification function, start it simultaneously; if not, start the independent humidifier to increase the water vapor content in the air to 6g / m 3 above.

[0068] Dynamic adjustment: The central control unit dynamically adjusts the heating power and humidification intensity according to the target dew point temperature to ensure that the dew point temperature is raised to above 0°C.

[0069] The second stage: turn on the indoor unit to cause condensation and frost on the heat exchanger surface;

[0070] Start cooling mode: After the first stage, switch to cooling mode and start the cooling function of the evaporator to reduce its surface temperature below the dew point temperature to promote condensation and frosting.

[0071] Turn on the indoor unit fan: Start the indoor unit fan to circulate the indoor air at medium speed to ensure that high-humidity air continuously flows over the evaporator surface, promoting the formation of condensed water and the formation of frost.

[0072] Condensation and frost formation: Condensation condenses on the surface of the evaporator and gradually frosts, and dust is gathered and fixed in the frost layer along with the condensation.

[0073] The third stage: melt the frost on the surface of the heat exchanger and remove the dust;

[0074] Switch back to heating mode: After condensation and frosting are completed, the system automatically returns to heating mode, raising the indoor temperature and melting the frost on the evaporator surface.

[0075] Embodiment 2: When the temperature is greater than 10°C and the relative humidity of the indoor air is greater than 30%;

[0076] Phase 1: Increase dew point temperature and absolute humidity;

[0077] Start heating mode: When the indoor temperature is detected to be greater than 10℃ and the relative humidity is greater than 30%, it will automatically switch to heating mode.

[0078] Heating and humidification:

[0079] Moderately increase the indoor temperature: Raise the indoor temperature to between 11-24°C to increase the amount of saturated water vapor in the air.

[0080] Start the humidification function: Start the built-in humidification function of the air conditioner or an independent humidifier to increase the absolute humidity to 9g / m 3 above.

[0081] Dynamic adjustment: The central control unit dynamically adjusts the heating power and humidification intensity according to the target dew point temperature to ensure that the dew point temperature rises.

[0082] The second stage: turn on the indoor unit to cause condensation and frost on the heat exchanger surface;

[0083] Start the refrigeration function of the evaporator to reduce its surface temperature to below the dew point temperature (about 12°C) to promote condensation and frosting;

[0084] The condensed water condenses on the surface of the evaporator and gradually forms frost.

[0085] The third stage: melt the frost on the surface of the heat exchanger and remove the dust;

[0086] After condensation and frosting are completed, the system returns to heating mode, further raising the indoor temperature to 22°C to melt the frost on the evaporator surface.

[0087] As the frost layer melts, the dust attached to the frost layer is taken away and discharged through the internal drainage system or stored in a designated location, ensuring the cleanliness of the condenser surface.

[0088] Example 3, when the room temperature is less than 10°C:

[0089] Stage 1: Raise the dew point temperature to make it higher than the freezing point;

[0090] Start heating mode: When the indoor temperature is detected to be less than 10°C, it will automatically switch to heating mode;

[0091] Start the humidification function: Use a humidifier to increase the absolute humidity to 5g / m 3 , ensure that the dew point temperature rises above 2°C.

[0092] The second stage: turn on the indoor unit to cause condensation and frost on the heat exchanger surface;

[0093] Start cooling mode: Before starting, make sure the indoor temperature is above 10℃ and the dew point temperature is above 0℃ to avoid condensation.

[0094] Start evaporator cooling: Start the evaporator's cooling function to reduce its surface temperature to below the dew point temperature (about 2°C), promoting condensation and frosting.

[0095] The third stage: melt the frost on the surface of the heat exchanger and remove the dust;

[0096] Switch back to heating mode: After condensation and frosting are completed, return to heating mode, increase the indoor temperature to 14°C, and melt the frost on the evaporator surface.

[0097] In addition, if the air conditioner includes a fresh air function, the goal is also to increase the dew point temperature and absolute humidity, then the first stage is improved to obtain the following embodiment:

[0098] Example 4: In the first stage, the indoor absolute humidity is increased according to the following method:

[0099] S1, turn on the refrigeration function to make the evaporator surface frosted;

[0100] S2, turn on the heating function to melt the frost on the evaporator surface, forming water droplets, which are stored in the indoor unit;

[0101] S3, turn on the fresh air function to exhaust the dry air in the room and bring in the wet air from the outside.

[0102] In S1, the evaporator continuously absorbs heat and refrigerates, causing the surrounding air to reach the dew point and then the freezing point, causing the water vapor in the indoor air to frost on the surface of the evaporator, and the water vapor in the indoor air is gathered on the evaporator surface;

[0103] In S2, the heating mode is turned on to melt the frost on the evaporator surface;

[0104] Preferably, the fan of the indoor unit is not turned on in S2;

[0105] Not turning on the fan can reduce the evaporation of water droplets produced by melting, and try to keep the water produced by melting in the air conditioner indoor unit;

[0106] In S3, after the fresh air mode of the air conditioner is turned on, the dry air in the room is discharged from the exhaust vent, and the humid air outside is introduced into the room through the heat exchange module;

[0107] Preferably, in S3, the moisture in the indoor unit in S2 is introduced into the fresh air outlet;

[0108] The airflow passing through the fresh air outlet can quickly evaporate the water originally produced by the evaporator.

[0109] By adopting the above method, the dew point is guaranteed to be greater than 0℃, and the evaporator absorbs heat for refrigeration. At this time, condensed water is generated first, and there are dry and wet areas in the ash layer. The unfrosted condensed water will be evenly distributed in the ash layer under the action of penetration.

[0110] In addition, after the first stage, during the second stage of evaporator cooling, the absolute humidity and temperature in the room are initially high, and the temperature of the indoor air continues to decrease during the operation of the evaporator, which causes the saturated water vapor pressure of the indoor air to continue to decrease; before frosting, more condensed water will be generated on the fins of the evaporator compared to the case of lower room temperature and relative humidity.

[0111] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A self-cleaning method for a heat exchanger, characterized in that: It consists of three stages; In the first stage, the dew point temperature is increased so that the dew point temperature is above the freezing point; In the second stage, the indoor unit is turned on to cause condensation and frost to form on the surface of the heat exchanger; In the third stage, the frost layer on the surface of the heat exchanger is melted.

2. A self-cleaning method for a heat exchanger according to claim 1, characterized in that: In the first stage, the indoor unit heat exchanger is in heating mode and the fan is turned on.

3. A self-cleaning method for a heat exchanger according to claim 2, characterized in that: In the first stage the humidification module is switched on.

4. A self-cleaning method for a heat exchanger according to claim 3, characterized in that: The indoor unit also includes a humidity sensor module, and the control system dynamically adjusts the heating power and humidification intensity according to the dew point temperature provided by the humidity sensor module.

5. A self-cleaning method for a heat exchanger according to claim 4, characterized in that: When the cooling mode is turned on, the dew point is greater than 0°C and the fan of the indoor unit is turned on.

6. The self-cleaning method of a heat exchanger according to claim 1, characterized in that: The indoor unit also includes a fresh air module, and the first stage also includes three steps: S1, turn on the refrigeration function to make the evaporator surface frosted; S2, turn on the heating function to melt the frost on the evaporator surface, forming water droplets, which are stored in the indoor unit; S3, turn on the fresh air function to exhaust the dry air in the room and bring in the wet air from the outside.

7. A self-cleaning method for a heat exchanger according to claim 6, characterized in that: In S2, the fan of the indoor unit is not turned on.

8. A self-cleaning method for a heat exchanger according to claim 6, characterized in that: Introduce the moisture in the indoor unit of S3 into the fresh air outlet.

9. An air conditioner, characterized in that: Execute the method according to any one of claims 1 to 5.

10. An air conditioner, characterized in that: It also includes a fresh air system for executing the method as described in any one of claims 6-8.

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