CN113028682B - Oil return control method and air conditioner - Google Patents
Oil return control method and air conditioner Download PDFInfo
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- CN113028682B CN113028682B CN202110342821.3A CN202110342821A CN113028682B CN 113028682 B CN113028682 B CN 113028682B CN 202110342821 A CN202110342821 A CN 202110342821A CN 113028682 B CN113028682 B CN 113028682B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B31/00—Compressor arrangements
- F25B31/002—Lubrication
- F25B31/004—Lubrication oil recirculating arrangements
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B49/00—Arrangement or mounting of control or safety devices
- F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
Abstract
The invention provides an oil return control method and an air conditioner, and relates to the technical field of air conditioners. The oil return control method comprises the following steps: setting a target refrigerant flow velocity V according to the pipe diameter D of the air distribution pipe and the height difference delta H between the outdoor unit and the indoor unit1(ii) a Obtaining the density rho of the refrigerantsAnd refrigerant mass flow rate M; according to the pipe diameter D of the gas distribution pipe and the density rho of the refrigerantsAnd the mass flow M of the refrigerant, and calculating the actual flow velocity V of the refrigerant2(ii) a According to the target refrigerant flow velocity V1And the actual refrigerant flow velocity V2Adjusting the rotational speed V of the compressor3So as to make the actual refrigerant flow velocity V2Achieve the target refrigerant flow velocity V1. In this way, the rotation speed V of the compressor is adjusted in the cooling mode that the outdoor unit is positioned higher than the indoor unit or in the heating mode that the indoor unit is positioned higher than the outdoor unit3So as to make the actual refrigerant flow velocity V2Achieve the target refrigerant flow velocity V1The oil return control device can prevent the insufficient oil return amount caused by the insufficient flow rate of the refrigerant in the oil return control process, thereby preventing the damage of the compressor caused by the insufficient oil amount.
Description
Technical Field
The invention relates to the technical field of air conditioners, in particular to an oil return control method and an air conditioner.
Background
In the conventional air conditioner, if the position of the outdoor unit is higher than that of the indoor unit and is in a cooling mode, or if the position of the outdoor unit is lower than that of the indoor unit and is in a heating mode, in the oil return control process, a refrigerant in an air distribution pipe flows from the indoor unit to the outdoor unit, the refrigerant is in an upward flow and has a low flow rate, the amount of oil moving along with the refrigerant is small, oil return is likely to be insufficient, and the larger the difference between the position of the outdoor unit and the position of the indoor unit is, the less the amount of oil return is likely to be insufficient.
Also, in the case where the oil return amount may be further reduced, first, the cooling mode is turned on, the amount of oil discharged from the compressor is large, and the oil stays for a long time in an external low temperature environment; second, the temperature of the refrigerant in the air distribution pipe is low, the viscosity of the oil is high, and the oil is difficult to move under the conditions of low outdoor temperature or low indoor temperature.
Therefore, in the process of oil return control of the conventional air conditioner, oil is difficult to convey in both a cooling mode and a heating mode, so that the oil return amount is insufficient and the compressor is damaged.
Disclosure of Invention
The invention solves the problems that: in the process of oil return control of the conventional air conditioner, oil conveying is difficult in both a cooling mode and a heating mode, so that the conditions of insufficient oil return amount and damage of a compressor can occur.
In order to solve the above problem, in a first aspect, the present invention provides an oil return control method, including:
setting a target refrigerant flow velocity V according to the pipe diameter D of the air distribution pipe and the height difference delta H between the outdoor unit and the indoor unit1；
Obtaining the density rho of the refrigerantsAnd refrigerant mass flow rate M;
according to the pipe diameter D of the gas distribution pipe and the density rho of the refrigerantsAnd the mass flow M of the refrigerant, and calculating the actual flow velocity V of the refrigerant2；
According to the target refrigerant flow velocity V1And the actual refrigerant flow velocity V2Adjusting the rotational speed V of the compressor3So as to make the actual refrigerant flow velocity V2Achieve the target refrigerant flow velocity V1。
First, in a cooling mode in which the outdoor unit is positioned higher than the indoor unit or in a heating mode in which the indoor unit is positioned higher than the outdoor unit, a target refrigerant flow velocity V is compared1And the actual refrigerant flow velocity V2And adjusting the rotational speed V of the compressor3So as to make the actual refrigerant flow velocity V2Achieve the target refrigerant flow velocity V1The oil return control device can prevent the insufficient oil return amount caused by the insufficient flow rate of the refrigerant in the oil return control process, thereby preventing the damage of the compressor caused by the insufficient oil amount.
Secondly, by adjusting the compressor speed V3The unnecessary rotation speed V of the compressor can be prevented by changing the flow rate of the refrigerant in the oil return control3The increase reduces the consumption of electric power, and also prevents the reliability of the compressor from being reduced due to the increase of the discharge pressure or the reduction of the suction pressure.
In an alternative embodiment, the target refrigerant flow rate V is determined according to1And the actual refrigerant flow velocity V2Adjusting the rotational speed V of the compressor3So as to make the actual refrigerant flow velocity V2Achieve the target refrigerant flow velocity V1Comprises the following steps:
when V is2＜V1While increasing the compressor speed V3；
When V is2＝V1While maintaining the compressor rotation speed V3The change is not changed;
when V is2＞V1While reducing the compressor speed V3。
Thus, according to the target refrigerant flow velocity V1And the actual refrigerant flow velocity V2Can accurately and quickly regulate the rotating speed V of the compressor3To make the actual refrigerant flow velocity V2Quickly reach target refrigerant flow velocity V1。
In an alternative embodiment, the target refrigerant flow velocity V1The following formula is satisfied:
F＝(ρs*V1/((ρo-ρs)*g*D))1/2
wherein F is a flow velocity calculation parameter and is determined according to Delta H, rhosIs the density of the refrigerant, ρoIs the oil density and g is the acceleration of gravity.
In an alternative embodiment, the flow rate calculation parameter F satisfies the following condition:
when the delta H is more than 0 and in the refrigeration mode, F is more than or equal to 1.2;
when the delta H is 0, F is more than or equal to 1.0;
when Delta H is less than 0 and in the heating mode, F is more than or equal to 0.8.
Therefore, the values of the corresponding flow rate calculation parameters F are respectively determined under the various conditions, so that the gas refrigerant can be ensured to convey liquid oil, and the oil return efficiency is ensured.
In an alternative embodiment, the target refrigerant flow velocity V1The following conditions are satisfied:
when Delta H is more than 0 and in the cooling mode, V is less than or equal to 6m/s1≤6.5m/s；
When Δ H is 0, 4.2 m/s.ltoreq.V1≤4.7m/s；
When Delta H is less than 0 and in the heating mode, V is less than or equal to 2.7m/s1≤3.3m/s。
Thus, the corresponding target refrigerant flow velocity V is determined under each of the above conditions1The oil return amount can be sufficient.
In an alternative embodiment, the refrigerant density ρ is obtainedsAnd the refrigerant mass flow M comprises the following steps:
in the cooling mode, the suction pressure P is measuredsAnd the suction temperature Ts；
According to suction pressure PsAnd the suction temperature TsCalculating the density rho of the refrigerants；
According to the density rho of the refrigerantsCompressor cylinder volume C and compressor speed V3And calculating the mass flow M of the refrigerant.
In an alternative embodiment, the refrigerant density ρsIncluding a first refrigerant density rho1Obtaining the density rho of the refrigerantsAnd the refrigerant mass flow M comprises the following steps:
in the heating mode, the suction pressure P is measuredsAnd the suction temperature Ts；
According to suction pressure PsAnd the suction temperature TsCalculating the first refrigerant density rho1；
According to the first refrigerant density rho1Compressor cylinder volume C and compressor speed V3And calculating the mass flow M of the refrigerant.
In an alternative embodiment, the refrigerant density ρsIncluding a second refrigerant density rho2According to the pipe diameter D of the gas distribution pipe and the density rho of the refrigerantsAnd the mass flow M of the refrigerant, and calculating the actual flow velocity V of the refrigerant2Comprises the following steps:
in the heating mode, the exhaust pressure P is measureddAnd exhaust temperature Td；
According to the exhaust pressure PdAnd exhaust temperature TdCalculating the second refrigerant density rho2；
According to the pipe diameter D of the gas distribution pipe and the density rho of a second refrigerant2And the mass flow M of the refrigerant, and calculating the actual flow velocity V of the refrigerant2。
In an alternative embodiment, the actual refrigerant flow velocity V2The calculation formula of (2) is as follows:
V2＝M/(ρs*(π*D2/4)
wherein M is the refrigerant mass flow rate, rhosIs the refrigerant density.
In a second aspect, the present invention provides an air conditioner comprising:
a storage for storing the diameter D of the air distribution pipe, the height difference delta H between the outdoor unit and the indoor unit and the target refrigerant flow velocity V1The corresponding relationship of (a);
a processor for processing the refrigerant according to the pipe diameter D and the refrigerant density rho of the gas distribution pipesAnd the mass flow M of the refrigerant, and calculating the actual flow velocity V of the refrigerant2According to the target refrigerant flow velocity V1And the actual refrigerant flow velocity V2Adjusting the rotational speed V of the compressor3So as to make the actual refrigerant flow velocity V2Achieve the target refrigerant flow velocity V1。
Thus, the air conditioner can prevent the insufficient oil return amount caused by the insufficient flow velocity of refrigerant in the oil return control process, thereby preventing the damage of the compressor caused by the insufficient oil amount and preventing the unnecessary rotating speed V of the compressor3Thereby reducing the consumption of electricity and preventing the reliability of the compressor from being lowered due to the increase of the discharge pressure or the decrease of the suction pressure.
Drawings
Fig. 1 is a flowchart of an oil return control method according to a first embodiment of the present invention;
fig. 2 is a flowchart of an oil return control method according to a second embodiment of the present invention;
fig. 3 is a schematic structural diagram of an air conditioner according to a second embodiment of the present invention.
Description of reference numerals:
1-an air conditioner; 2-a memory; 3-a processor; 4-compressor.
Detailed Description
In the oil return control process of the existing air conditioner, the rotating speed of a compressor is a specified value or is controlled by the pressure born by a refrigerant (hereinafter, referred to as refrigerant pressure). However, in the cooling mode in which the outdoor unit is located higher than the indoor unit, or in the heating mode in which the outdoor unit is located lower than the indoor unit, the refrigerant flows upward, that is, the refrigerant flows from a lower position to a higher position, and the amount of oil moving with the refrigerant is small, and thus there is a possibility that the oil return is insufficient.
In the cooling mode, the refrigerant pressure becomes the suction pressure, and in the heating mode, the refrigerant pressure becomes the discharge pressure. In this way, when the rotational speed of the compressor is controlled by the suction pressure in the cooling mode in a low-temperature environment, the suction pressure decreases, the rotational speed of the compressor decreases, the refrigerant circulation amount also decreases, and oil return may be insufficient. When the heating mode is performed in a high-temperature environment and the rotation speed of the compressor is controlled by the exhaust pressure, the rotation speed of the compressor is reduced due to the increase of the exhaust pressure, the refrigerant circulation amount is also reduced, and the oil return shortage may occur.
In short, in the oil return control of the conventional air conditioner, it is not considered that the refrigerant flow rate varies depending on the refrigerant circulation amount and the refrigerant density in the air distribution pipe, and the refrigerant flow rate cannot be controlled with high accuracy, so that the oil return amount may be insufficient to damage the compressor in the above case.
The embodiment of the invention provides an oil return control method, which can prevent the insufficient oil return amount caused by the insufficient flow velocity of a refrigerant in oil return control by adjusting the rotating speed of a compressor.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.
First embodiment
Referring to fig. 1, the present embodiment provides an oil return control method, which is mainly applied to a refrigeration mode process of an air conditioner, and the oil return control method includes the following steps:
s11: setting a target according to the pipe diameter D of the gas distribution pipe and the height difference delta H between the outdoor unit and the indoor unitVelocity of flow V of refrigerant1。
Wherein the pipe diameter D of the gas distribution pipe refers to the inner diameter of the gas distribution pipe, and the target refrigerant flow velocity V1The following formula is satisfied:
F＝(ρs*V1/((ρo-ρs)*g*D))1/2
wherein F is a flow velocity calculation parameter and is determined according to Delta H; rhosIs the density of refrigerant in kg/m3；ρoIs the oil density in kg/m3(ii) a g is the acceleration of gravity, equal to 9.8m/s2。
The flowing directions of the refrigerant in the gas distribution pipe are respectively ascending flow, horizontal flow and descending flow, and the following discussion is respectively carried out on three flow directions of the refrigerant:
(1) when the refrigerant is ascending flow, namely when the delta H is more than 0 and under the refrigeration mode:
(ρs*V1/((ρo-ρs)*g*D))1/2＝F≥1.2
where Δ H > 0 indicates that the outdoor unit is positioned higher than the indoor unit.
Calculated, when Δ H > 0 and in the cooling mode, the target refrigerant flow velocity V1The value ranges of (a) may be: v is less than or equal to 6m/s1Less than or equal to 6.5m/s, preferably 6m/s, and can ensure sufficient oil return amount.
(2) When the refrigerant is a horizontal flow, that is, when Δ H is 0:
(ρs*V1/((ρo-ρs)*g*D))1/2＝F≥1.0
where Δ H ═ 0 indicates that the outdoor unit and the indoor unit are at the same height.
Calculated, when Δ H is 0, the target refrigerant flow velocity V1The value ranges of (a) may be: v is not more than 4.2m/s1Less than or equal to 4.7m/s, preferably 4.2m/s, and can ensure sufficient oil return amount.
(3) When the refrigerant is a descending flow, namely delta H is less than 0, and in the heating mode:
(ρs*V1/((ρo-ρs)*g*D))1/2＝F≥0.8
wherein Δ H < 0 indicates that the position of the outdoor unit is lower than the position of the indoor unit.
Calculated, when the delta H is less than 0 and in the heating mode, the target refrigerant flow velocity V1The value ranges of (a) may be: v is less than or equal to 2.7m/s1Less than or equal to 3.3m/s, preferably 2.7m/s, and can ensure sufficient oil return amount.
Therefore, the values of the corresponding flow rate calculation parameters F are respectively determined under the various conditions, so that the gas refrigerant can be ensured to convey liquid oil, and the oil return efficiency is ensured.
S12: in the cooling mode, the suction pressure P is measuredsAnd the suction temperature Ts。
Wherein, in the cooling mode, the pressure of the gas piping is substantially equal to the suction pressure Ps。
S13: according to suction pressure PsAnd the suction temperature TsCalculating the density rho of the refrigerants。
Wherein the density of the refrigerant is rhosThe actual density of the low-pressure air-cooling medium can be obtained by using a refrigerant density calculation formula or a conversion table. The refrigerant density calculation formula or conversion table is made by the air conditioner designer by using the physical properties of the refrigerant and calculation software, and for example, the refrigerant is assumed to be a saturated gaseous refrigerant, and the refrigerant density ρ is obtained according to the boyle formulas。
S14: according to the density rho of the refrigerantsCompressor cylinder volume C and compressor speed V3And calculating the mass flow M of the refrigerant.
Wherein, the refrigerant mass flow M is equal to the flow of the refrigerant discharged by the compressor according to the volume C of the compressor cylinder and the rotating speed V of the compressor3The volume of the refrigerant discharged from the compressor is obtained, and the volume of the refrigerant discharged from the compressor is multiplied by the density rho of the refrigerantsThe refrigerant discharge amount of the compressor, that is, the refrigerant mass flow rate M, can be obtained.
S15: according to the pipe diameter D of the gas distribution pipe and the density rho of the refrigerantsAnd the mass flow M of the refrigerant, and calculating the actual flow velocity V of the refrigerant2。
Wherein the actual refrigerant flow velocity V2Is calculated byThe formula is as follows:
V2＝M/(ρs*(π*D2/4)
wherein M is the refrigerant mass flow rate, rhosIs the refrigerant density.
S16: according to the target refrigerant flow velocity V1And the actual refrigerant flow velocity V2Adjusting the rotational speed V of the compressor3So as to make the actual refrigerant flow velocity V2Achieve the target refrigerant flow velocity V1。
Specifically, when V2＜V1While increasing the compressor speed V3(ii) a When V is2＝V1While maintaining the compressor rotation speed V3The change is not changed; when V is2＞V1While reducing the compressor speed V3. Thus, according to the target refrigerant flow velocity V1And the actual refrigerant flow velocity V2Can accurately and quickly regulate the rotating speed V of the compressor3To make the actual refrigerant flow velocity V2Quickly reach target refrigerant flow velocity V1。
Wherein the rotational speed V of the compressor is adjusted each time3Thereafter, it returns to S12 until V1＝V2。
The oil return control method provided by the embodiment of the invention has the beneficial effects that:
1. comparing the target refrigerant flow velocity V in a cooling mode in which the outdoor unit is positioned higher than the indoor unit and in a heating mode in which the indoor unit is positioned higher than the outdoor unit1And the actual refrigerant flow velocity V2And adjusting the rotational speed V of the compressor3So as to make the actual refrigerant flow velocity V2Achieve the target refrigerant flow velocity V1The oil return control device can prevent the insufficient oil return amount caused by the insufficient flow velocity of the refrigerant in the oil return control process, thereby preventing the damage of the compressor caused by the insufficient oil amount;
2. by adjusting the speed V of the compressor3The unnecessary rotation speed V of the compressor can be prevented by changing the flow rate of the refrigerant in the oil return control3The increase reduces the consumption of electric power, and also prevents the reliability of the compressor from being reduced due to the increase of the discharge pressure or the reduction of the suction pressure.
Second embodiment
Referring to fig. 2, the present embodiment provides an oil return control method, which is mainly applied to a heating mode process of an air conditioner, and the oil return control method includes the following steps:
s21: setting a target refrigerant flow velocity V according to the pipe diameter D of the air distribution pipe and the height difference delta H between the outdoor unit and the indoor unit1。
Wherein the target refrigerant flow velocity V1The following formula is satisfied:
F＝(ρs*V1/((ρo-ρs)*g*D))1/2
wherein F is a flow velocity calculation parameter and is determined according to Delta H; rhosIs the density of refrigerant in kg/m3；ρoIs the oil density in kg/m3(ii) a g is the acceleration of gravity, equal to 9.8m/s2。
The flowing directions of the refrigerant in the gas distribution pipe are respectively ascending flow, horizontal flow and descending flow, and the following discussion is respectively carried out on three flow directions of the refrigerant:
(1) when the refrigerant is ascending flow, namely when the delta H is more than 0 and under the refrigeration mode:
(ρs*V1/((ρo-ρs)*g*D))1/2＝F≥1.2
where Δ H > 0 indicates that the outdoor unit is positioned higher than the indoor unit.
Calculated, when Δ H > 0 and in the cooling mode, the target refrigerant flow velocity V1The value ranges of (a) may be: v is less than or equal to 6m/s1Less than or equal to 6.5m/s, preferably 6m/s, and can ensure sufficient oil return amount.
(2) When the refrigerant is a horizontal flow, that is, when Δ H is 0:
(ρs*V1/((ρo-ρs)*g*D))1/2＝F≥1.0
where Δ H ═ 0 indicates that the outdoor unit and the indoor unit are at the same height.
Calculated, when Δ H is 0, the target refrigerant flow velocity V1The value ranges of (a) may be: v is not more than 4.2m/s14.7m/s or less, preferably 4.2m/s,the oil return amount can be ensured to be sufficient.
(3) When the refrigerant is a descending flow, namely delta H is less than 0, and in the heating mode:
(ρs*V1/((ρo-ρs)*g*D))1/2＝F≥0.8
wherein Δ H < 0 indicates that the position of the outdoor unit is lower than the position of the indoor unit.
Calculated, when the delta H is less than 0 and in the heating mode, the target refrigerant flow velocity V1The value ranges of (a) may be: v is less than or equal to 2.7m/s1Less than or equal to 3.3m/s, preferably 2.7m/s, and can ensure sufficient oil return amount.
Therefore, the values of the corresponding flow rate calculation parameters F are respectively determined under the various conditions, so that the gas refrigerant can be ensured to convey liquid oil, and the oil return efficiency is ensured.
S22: in the heating mode, the suction pressure P is measuredsAnd the suction temperature Ts。
S23: according to suction pressure PsAnd the suction temperature TsCalculating the first refrigerant density rho1。
Wherein the first refrigerant density rho1The actual density of the low-pressure air-cooling medium can be obtained by using a refrigerant density calculation formula or a conversion table. The refrigerant density calculation formula or conversion table is made by the air conditioner designer by using the physical properties of the refrigerant and calculation software, and for example, the refrigerant is assumed to be a saturated gaseous refrigerant, and the first refrigerant density ρ is obtained according to the boyle formula1。
S24: according to the first refrigerant density rho1Compressor cylinder volume C and compressor speed V3And calculating the mass flow M of the refrigerant.
Wherein, the refrigerant mass flow M is equal to the refrigerant discharge quantity of the compressor according to the cylinder volume C of the compressor and the rotating speed V of the compressor3The volume of the refrigerant discharged by the compressor is obtained, and the volume of the refrigerant discharged by the compressor is multiplied by the first refrigerant density rho1The refrigerant discharge amount of the compressor, that is, the refrigerant mass flow rate M, can be obtained.
S25: in the heating mode, measureConstant exhaust pressure PdAnd exhaust temperature Td。
Wherein, in the heating mode, the pressure of the gas piping is substantially equal to the discharge pressure Pd。
S26: according to the exhaust pressure PdAnd exhaust temperature TdCalculating the second refrigerant density rho2。
Wherein the second refrigerant density ρ2The actual density of the high-pressure air-cooling medium can be obtained by using a refrigerant density calculation formula or a conversion table. The refrigerant density calculation formula or conversion table is made by the air conditioner designer by using the physical properties of the refrigerant and calculation software, and for example, the refrigerant is assumed to be a saturated gaseous refrigerant, and the second refrigerant density ρ is obtained according to the boyle formula2。
S27: according to the pipe diameter D of the gas distribution pipe and the density rho of a second refrigerant2And the mass flow M of the refrigerant, and calculating the actual flow velocity V of the refrigerant2。
Wherein the actual refrigerant flow velocity V2The calculation formula of (2) is as follows:
V2＝M/(ρ2*(π*D2/4)
wherein M is the refrigerant mass flow.
S28: according to the target refrigerant flow velocity V1And the actual refrigerant flow velocity V2Adjusting the rotational speed V of the compressor3So as to make the actual refrigerant flow velocity V2Achieve the target refrigerant flow velocity V1。
Specifically, when V2＜V1While increasing the compressor speed V3(ii) a When V is2＝V1While maintaining the compressor rotation speed V3The change is not changed; when V is2＞V1While reducing the compressor speed V3. Thus, according to the target refrigerant flow velocity V1And the actual refrigerant flow velocity V2Can accurately and quickly regulate the rotating speed V of the compressor3To make the actual refrigerant flow velocity V2Quickly reach target refrigerant flow velocity V1。
Wherein the rotational speed V of the compressor is adjusted each time3Thereafter, it returns to S22 until V1＝V2。
The oil return control method provided by the embodiment of the invention has the beneficial effects that:
1. comparing the target refrigerant flow velocity V in a cooling mode in which the outdoor unit is positioned higher than the indoor unit and in a heating mode in which the indoor unit is positioned higher than the outdoor unit1And the actual refrigerant flow velocity V2And adjusting the rotational speed V of the compressor3So as to make the actual refrigerant flow velocity V2Achieve the target refrigerant flow velocity V1The oil return control device can prevent the insufficient oil return amount caused by the insufficient flow velocity of the refrigerant in the oil return control process, thereby preventing the damage of the compressor caused by the insufficient oil amount;
2. by adjusting the speed V of the compressor3The unnecessary rotation speed V of the compressor can be prevented by changing the flow rate of the refrigerant in the oil return control3The increase reduces the consumption of electric power, and also prevents the reliability of the compressor from being reduced due to the increase of the discharge pressure or the reduction of the suction pressure.
Third embodiment
Referring to fig. 3, the present embodiment provides an air conditioner 1, the air conditioner 1 includes a memory 2, a processor 3 and a compressor 4, wherein the memory 2 stores a pipe diameter D of an air distribution pipe, a height difference Δ H between an outdoor unit and an indoor unit, and a target refrigerant flow velocity V1The memory 2 further stores a program corresponding to the oil return control method provided in the first embodiment or the second embodiment, the processor 3 is connected to the compressor 4, and the processor 3 reads the program in the memory 2 to execute the oil return control method provided in the first embodiment or the second embodiment.
Thus, the air conditioner 1 can prevent the shortage of the oil return amount due to the shortage of the refrigerant flow rate during the oil return control, thereby preventing the damage of the compressor due to the shortage of the oil amount, and preventing the unnecessary rotation speed V of the compressor3Thereby reducing the consumption of electricity and preventing the reliability of the compressor from being lowered due to the increase of the discharge pressure or the decrease of the suction pressure.
Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (9)
1. An oil return control method, characterized in that the oil return control method comprises:
setting a target refrigerant flow velocity V according to the pipe diameter D of the air distribution pipe and the height difference delta H between the outdoor unit and the indoor unit1；
Obtaining the density rho of the refrigerantsAnd refrigerant mass flow rate M;
according to the pipe diameter D of the gas distribution pipe and the density rho of the refrigerantsAnd the mass flow M of the refrigerant, and calculating the actual refrigerant flow velocity V2；
According to the target refrigerant flow velocity V1And the actual refrigerant flow velocity V2Adjusting the rotational speed V of the compressor3So that the actual refrigerant flow velocity V2The target refrigerant flow velocity V is achieved1The target refrigerant flow velocity V1The following formula is satisfied:
F=（ρs*V1/（（ρo-ρs）*g*D））1/2
wherein F is a flow velocity calculation parameter and is determined according to Delta H, rhosIs the density of the refrigerant, ρoIs the oil density and g is the acceleration of gravity.
2. The oil return control method according to claim 1, wherein the target refrigerant flow rate V is set according to the target refrigerant flow rate V1And the actual refrigerant flow velocity V2Adjusting the rotational speed V of the compressor3So that the actual refrigerant flow velocity V2The target refrigerant flow velocity V is achieved1Comprises the following steps:
when V is2＜V1While increasing the compressor speed V3；
When V is2=V1While maintaining the compressor speed V3The change is not changed;
when V is2＞V1While reducing the compressor speed V3。
3. The oil return control method according to claim 1, wherein the flow rate calculation parameter F satisfies the following condition:
when the delta H is more than 0 and in the refrigeration mode, F is more than or equal to 1.2;
when Δ H =0, F ≧ 1.0;
when Delta H is less than 0 and in the heating mode, F is more than or equal to 0.8.
4. The oil return control method according to claim 3, wherein the target refrigerant flow rate V1The following conditions are satisfied:
when Delta H is more than 0 and in the cooling mode, V is less than or equal to 6m/s1≤6.5m/s；
When Δ H =0, 4.2m/s ≦ V1≤4.7m/s；
When Delta H is less than 0 and in the heating mode, V is less than or equal to 2.7m/s1≤3.3m/s。
5. The oil return control method according to claim 1, wherein the acquisition of the refrigerant density ρsAnd the refrigerant mass flow M comprises the following steps:
in the cooling mode, the suction pressure P is measuredsAnd the suction temperature Ts；
According to the suction pressure PsAnd said suction temperature TsCalculating the density rho of the refrigerants；
According to the density rho of the refrigerantsCompressor cylinder volume C and said compressor speed V3And calculating the mass flow M of the refrigerant.
6. The oil return control method according to claim 1, wherein the refrigerant density ρ issIncluding a first refrigerant density rho1Obtaining the density rho of the refrigerantsAnd the refrigerant mass flow M comprises the following steps:
in the heating mode, the suction pressure P is measuredsAnd the suction temperature Ts；
According to the suction pressure PsAnd stationThe suction temperature TsCalculating the density rho of the first refrigerant1；
According to the first refrigerant density rho1Compressor cylinder volume C and said compressor speed V3And calculating the mass flow M of the refrigerant.
7. The oil return control method according to claim 6, wherein the refrigerant density ρ issIncluding a second refrigerant density rho2According to the pipe diameter D of the gas distribution pipe and the density rho of the refrigerantsAnd the mass flow M of the refrigerant, and calculating the actual refrigerant flow velocity V2Comprises the following steps:
in the heating mode, the exhaust pressure P is measureddAnd exhaust temperature Td；
According to the exhaust pressure PdAnd said exhaust temperature TdCalculating the density rho of the second refrigerant2；
According to the pipe diameter D of the gas distribution pipe and the density rho of the second refrigerant2And the mass flow M of the refrigerant, and calculating the actual refrigerant flow velocity V2。
8. The oil return control method according to claim 1, wherein the actual refrigerant flow rate V2The calculation formula of (2) is as follows:
V2=M/（ρs*（π*D2/4））
wherein M is the refrigerant mass flow rate, rhosIs the refrigerant density.
9. An air conditioner, characterized in that the air conditioner comprises:
a memory (2) for storing the pipe diameter D of the air distribution pipe, the height difference delta H between the outdoor unit and the indoor unit and the target refrigerant flow velocity V1The corresponding relationship of (a);
a processor (3) for processing the gas distribution pipe according to the pipe diameter D of the gas distribution pipe and the density rho of the refrigerantsAnd the mass flow M of the refrigerant, and calculating the actual flow velocity V of the refrigerant2According to the target refrigerant flow velocity V1And the actual refrigerant flow velocity V2Adjusting the rotational speed V of the compressor3So that the actual refrigerant flow velocity V2The target refrigerant flow velocity V is achieved1The target refrigerant flow velocity V1The following formula is satisfied:
F=（ρs*V1/（（ρo-ρs）*g*D））1/2
wherein F is a flow velocity calculation parameter and is determined according to Delta H, rhosIs the density of the refrigerant, ρoIs the oil density and g is the acceleration of gravity.
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Effective date of registration: 20221010 Address after: 315191 No. 1166 Mingguang North Road, Jiangshan Town, Ningbo, Zhejiang, Yinzhou District Patentee after: NINGBO AUX ELECTRIC Co.,Ltd. Patentee after: AUX AIR CONDITIONING LIMITED BY SHARE Ltd. Address before: 315000 No.1166 Mingguang North Road, Jiangshan Town, Yinzhou District, Ningbo City, Zhejiang Province Patentee before: NINGBO AUX ELECTRIC Co.,Ltd. Patentee before: Ningbo Oxfam intelligent commercial air conditioning manufacturing Co.,Ltd. |