WO2019052541A1

WO2019052541A1 - Method and device for controlling refrigeration of variable frequency air conditioner

Info

Publication number: WO2019052541A1
Application number: PCT/CN2018/105789
Authority: WO
Inventors: 刘卫兵; 吴洪金; 耿宝寒; 朱辉; 刘庆赟; 贾淑玲; 杜路明
Original assignee: 青岛海尔空调器有限总公司
Priority date: 2017-09-18
Filing date: 2018-09-14
Publication date: 2019-03-21
Also published as: CN107781945B; CN107781945A

Abstract

A method and device for controlling refrigeration of a variable frequency air conditioner. An indoor unit of the air conditioner comprises two evaporators (551, 552) connected in parallel, two fans (410, 420) corresponding to the two evaporators (551, 552), and two air outlet groups respectively corresponding to the two fans (410, 420). Each air outlet group comprises at least one air outlet (112, 114, 116). The refrigeration control method comprises: when an air conditioner operates in refrigeration mode, detecting an indoor target temperature Ta, an indoor environmental temperature Tb, an outdoor environmental temperature Tc and the temperatures of coil pipes (502, 503) of two evaporators (551, 552), a lower temperature value in the temperatures of the two coil pipes (502, 503) being Td; detecting the on-or-off state of the two fans (410, 420); if the two fans (410, 420) are both on, determining the operating frequencies of the compressors (510) according to the temperature range of Td and values of Ta, Tb and Tc; and if only one fan (410, 420) is on, determining the operating frequencies of the compressors (510) according to a temperature difference range Tb-Ta and the values of Ta, Tb and Tc. By means of the method, the operating frequencies of the compressors (510) are accurately controlled, so that the air conditioner can satisfy refrigeration requirements, and the evaporators (551, 552) can be prevented from being frozen.

Description

Refrigeration control method and device for inverter air conditioner

Technical field

The invention relates to the technical field of refrigeration, and in particular relates to a cooling control method and device for an inverter air conditioner.

Background technique

The inverter air conditioner usually calculates the real-time running frequency of the compressor according to the indoor target temperature set by the remote controller, the indoor ambient temperature, and the outdoor ambient temperature. However, some air conditioner indoor units are currently provided with two evaporators in parallel and two fans to achieve multiple modes of air supply. Therefore, it is often the case that only one fan is turned on.

During cooling, the evaporator part corresponding to the unopened fan is forced to convectively exchange heat with the fan, which makes the heat transfer unfavorable, which will result in a lower coil temperature, and the evaporator will freeze at an extreme temperature. Therefore, how to accurately control the operating frequency of the compressor, so that the air conditioner not only meets the cooling demand, but also avoids the freezing of the evaporator, has become an urgent problem to be solved.

Summary of the invention

An object of the present invention is to overcome the above-mentioned deficiencies of the prior art, and to provide a refrigeration control method and apparatus for an inverter air conditioner, which realizes precise control of the operating frequency of the compressor, so that the air conditioner can meet the cooling demand and avoid the evaporator. A freeze has occurred.

A further object of the present invention is to improve the intelligence of the air supply of the air conditioner, to achieve on-demand air supply and gentle air supply, and to enhance user comfort.

In particular, the present invention provides a cooling control method for an inverter air conditioner, wherein the indoor unit of the air conditioner includes two evaporators arranged in parallel, two fans respectively corresponding to the two evaporators, and each of the fans corresponds to at least one air outlet. Refrigeration control methods include:

When the inverter air conditioner is operated in the cooling mode, the indoor target temperature Ta, the indoor ambient temperature Tb, the outdoor ambient temperature Tc, and the coil temperatures of the two evaporators are detected, and the lower temperature values of the two coil temperatures are recorded as Td;

Detecting the open state of two fans;

If both fans are turned on, determine the operating frequency of the inverter of the inverter air conditioner according to the temperature range in which Td is located and the values of Ta, Tb, and Tc;

If only one fan is turned on, the operating frequency of the compressor is determined according to the temperature difference range of Tb-Ta and the values of Ta, Tb, and Tc.

Optionally, when both fans are turned on, the operating frequency of the compressor is determined as follows: when Td>T2, the compressor is controlled to operate at a frequency of f=f(Ta, Tb, Tc); when T1≤Td≤ T2, control compressor constant frequency operation, frequency f = f (Ta1, Tb1, Tc1), where Ta1, Tb1 and Tc1 are the indoor target temperature, indoor ambient temperature and outdoor ambient temperature when Td falls to T2, respectively; When Td < T1, the compressor is controlled to be down-converted so that its frequency f < f (Ta1, Tb1, Tc1).

Optionally, when only one fan is turned on, the operating frequency of the compressor is determined as follows: the frequency correction coefficient b=b(Tb-Ta) is calculated according to the temperature difference Tb-Ta, and the operating frequency of the compressor is controlled to f=b*f ( Ta, Tb, Tc), where b < 1.

Alternatively, when Tb-Ta<T3, b=b1; when T3≤Tb-Ta≤T4, b=b2; when Tb-Ta>T4, b=b3, where b1<b2<b3.

Alternatively, T1 = 0 ° C, T2 = 4 ° C, T3 = 7 ° C, T4 = 13 ° C, b1 = 0.5, b2 = 0.8, b3 = 0.9.

Optionally, the air conditioner comprises a compressor, a condenser, a tee, a first electronic expansion valve and a second electronic expansion valve, and two evaporators; wherein the inlet of the tee is connected to the outlet of the condenser, the tee Two outlets respectively communicate with the inlets of the first electronic expansion valve and the second electronic expansion valve; the outlets of the first electronic expansion valve and the second electronic expansion valve respectively communicate with the inlets of the two evaporators; and the two evaporator outlets are respectively connected and compressed Import of the machine.

Optionally, each air outlet is provided with: a vertical swinging leaf group, comprising a plurality of vertical pendulum leaves extending vertically and installed at the air outlet, the plurality of vertical swinging leaves being synchronously pivoted to adjust the left and right winds And a yaw group comprising a plurality of yaw leaves extending horizontally, which are mounted behind the vertical pendulum, and the plurality of yaw blades are pivoted synchronously to adjust the up and down direction of the wind.

Optionally, one fan corresponds to two air outlets, and the other fan corresponds to one air outlet; and three air outlets are arranged in a straight line.

Optionally, both fans are cross-flow fans.

Alternatively, both evaporators are finned evaporators and share the same set of fins, the coils of the two evaporators respectively matching the two halves of the set of fins.

According to another aspect of the present invention, there is also provided a refrigeration control apparatus for an inverter air conditioner, comprising a memory and a processor, wherein the memory stores therein a control program for implementing the frequency conversion of any of the above when the control program is executed by the processor Air conditioning refrigeration control method.

In the refrigeration control method for an inverter air conditioner according to the present invention, the operating frequency f = f (Ta, Tb, Tc) of the compressor is initially determined based on the indoor target temperature, the indoor ambient temperature, and the outdoor ambient temperature. When both fans are running, both evaporators get good heat exchange and there is less chance of over-freezing. At this time, the compressor frequency is corrected according to the coil temperature of the evaporator. When the coil temperature is lower than T1, the operating frequency is normally calculated according to the above function; when the coil temperature satisfies T1 ≤ Td ≤ T2, it is maintained Run at a fixed frequency to avoid further reduction in coil temperature. When the coil temperature Td<T1, the compressor is controlled to reduce the frequency, and the coil temperature of the evaporator is raised to prevent it from continuing to cool down and cause freezing. When only one fan is operated, in order to avoid the heat transfer of the evaporator portion which is not covered by the wind of the fan, the correction coefficient b of less than 1 is calculated according to the temperature difference Tb-Ta, the operating frequency of the compressor is reduced, and the evaporation temperature is raised. Avoid freezing the evaporator. It can be seen from the above that the present invention precisely controls the operating frequency of the compressor so that the air conditioner can satisfy both the cooling demand and the evaporator freezing.

Further, the air conditioner indoor unit is provided with two evaporators, two fans and a plurality of air outlets, which can adjust the number of fan opening, the wind speed and the refrigerant flow rate of the evaporator according to the cooling demand of the user, and realize the intelligent adjustment of the air volume and the cooling capacity. The air volume and cooling capacity are more closely matched to the indoor demand, which saves energy consumption of the air conditioner.

The above as well as other objects, advantages and features of the present invention will become apparent to those skilled in the <

DRAWINGS

Some specific embodiments of the present invention will be described in detail, by way of example, and not limitation, The same reference numbers in the drawings identify the same or similar parts. Those skilled in the art should understand that the drawings are not necessarily drawn to scale. In the figure:

1 is a schematic structural view of a portion of an indoor unit of an air conditioner according to an embodiment of the present invention;

2 is a schematic diagram of a refrigeration cycle of the air conditioning indoor unit shown in FIG. 1;

Figure 3 is an exploded perspective view showing the air blowing structure of the air conditioning indoor unit shown in Figure 1;

4 is a schematic structural view of an evaporator of an air conditioning indoor unit according to an embodiment of the present invention;

Figure 5 is a schematic view showing a cooling control method of an air conditioner according to an embodiment of the present invention;

6 is a flow chart showing a cooling control method of an air conditioner according to an embodiment of the present invention;

Figure 7 is a schematic block diagram of a refrigeration control apparatus for an inverter air conditioner according to an embodiment of the present invention.

Detailed ways

Embodiments of the present invention provide a cooling control method for an inverter air conditioner. 1 is a schematic structural view of an air conditioner indoor unit according to an embodiment of the present invention; FIG. 2 is a schematic diagram of a refrigeration cycle of the air conditioner indoor unit shown in FIG. 1; and FIG. 3 is an exploded perspective view of the air supply structure of the air conditioner indoor unit shown in FIG. 4 is a schematic structural view of an evaporator of an air conditioning indoor unit according to an embodiment of the present invention. Figure 2 only illustrates several major components of the refrigeration cycle system, and Figure 4 separates the two evaporators by dashed lines.

As shown in FIG. 1 to FIG. 4, the indoor unit of the inverter air conditioner includes a casing, two

evaporators

551, 552, two

fans

410, 420, a plurality of

air outlets

112, 114, 116, and a plurality of swinging blade assemblies. The evaporator 551, the fan 410 and the

air outlets

112, 114 are matched. The evaporator 552, the fan 420 and the air outlet 116 are matched. 1 shows only the front panel 110 of the housing. The front panel 110 is provided with the

aforementioned air outlets

112, 114, 116, and the rear side of the housing is not shown with an air inlet. The outdoor air enters the casing from the air inlet, passes through two

evaporators

551, 552 driven by the fan, and exchanges heat with the

evaporators

551, 552, and then blows into the room from the

corresponding air outlets

112, 114, 116 to achieve cooling/heating of the indoor environment.

In the embodiment shown in FIG. 1 to FIG. 4, the air outlet areas of the three

air outlets

112, 114, 116 can be set to be the same, and the number of air outlets matched by the evaporator 551 and the fan 410 is large, and the heat exchange capacity of the evaporator 551 is The air blowing capability of the fan 410 is greater than that of the evaporator 552 and the fan 420. For example, the two

evaporators

551, 552 can be used in the same heat exchange condition, the heat exchange amount of the evaporator 551 is twice that of the evaporator 552, so that the two fans are at the same speed, and the air volume of the fan 410 is the fan 420. Twice.

The two

fans

410, 420 may both be cross-flow fans. To make the connection between the cross-flow fan and the housing more stable, the motor 411 of the fan 410 may be located at the top thereof, and the motor 421 of the fan 420 is located at the bottom thereof. A bearing may be disposed between the two

fans

410, 420.

A plurality of swinging blade assemblies (eg, a plurality of yaw lobes 312 at the air outlet 112 and a plurality of yaw blades 322 forming a swinging leaf assembly) are matched with the plurality of

air outlets

112, 114, 116 for adjusting each air outlet wind direction.

The air conditioning indoor unit may further include a duct assembly that is erected between the fan 410, the fan 420 and the front panel 110, and includes a housing 120 and a plurality of partitions 121 defining a wind guide chamber that is open at the front and the rear. A plurality of partitions are vertically arranged in the outer casing to separate the air guiding chambers from the plurality of

air passages

123, 124, 125 isolated from each other, each air passage matching an air outlet for guiding the wind of the wind turbine to the air duct The air outlets and the winds flowing to the plurality of

air outlets

112, 114, 116 do not interfere with each other.

And, each pendulum assembly includes a pendulum group and a yaw group. Wherein, the vertical pendulum group includes a plurality of vertical pendulum leaves 312, 314, 316 extending vertically and installed at the

air outlets

112, 114, 116, and the plurality of vertical pendulum leaves can be synchronously pivoted to adjust the left and right direction of the wind. The yaw group includes a plurality of yaw leaves 324, 324, 326 extending horizontally, which are mounted in the

air ducts

123, 124, 125, and the plurality of yaw leaves are pivotally synchronized to adjust the up and down direction of the wind. By setting a motor to drive a yaw leaf (or vertical pendulum) to rotate, a hinge to the yaw leaf (or vertical pendulum) and the rest of the yaw leaf (or vertical pendulum) to achieve full horizontal Synchronous pivoting of the pendulum (or vertical pendulum). Of course, the yaw leaf can also be placed at the air outlet, and the vertical swing leaf can be placed in the air duct.

2, the air conditioner includes a compressor 510, a condenser 520, a three-way pipe 530, two

electronic expansion valves

541, 542, and two

evaporators

551, 552, wherein the inlet of the three-way pipe 530 is connected to the outlet of the condenser 520. The two outlets of the tee 530 communicate with the inlets of the two

electronic expansion valves

541, 542, respectively. The outlets of the two

electronic expansion valves

541, 542 communicate with the inlets of the evaporator 551 and the evaporator 552, respectively. The evaporator 551 and the outlet of the evaporator 552 communicate with the inlet of the compressor 510.

As shown in FIG. 1, the throttle element 541 is provided with a liquid separator 561, and the electronic expansion valve 542 is provided with a liquid separator 562, which is used to divide the refrigerant into multiple channels to improve the heat exchange efficiency of the evaporator. After flowing through the coils of the two evaporators, the refrigerant merges into the header 580 and flows from the collector 580 to the compressor 510.

In some embodiments, as shown in FIG. 4, the evaporator 551 and the evaporator 552 are finned evaporators, and the two

evaporators

551, 552 share the same fin set 501, and the coil 502 of the evaporator 551 is mounted on the fins. The upper portion of the group 501, the coil 503 of the evaporator 552 is attached to the lower portion of the fin group 501. Compared with the two evaporators independently and each self-installing scheme, the embodiment can facilitate the manufacture and installation of the

evaporators

551, 552, and also save the internal space of the casing.

In the process of inverter air conditioner refrigeration, the internal refrigerant of the evaporator is in a low temperature and low pressure state. If it cannot exchange heat with the air in time (ie, the evaporator coil absorbs heat), it will cause condensation, frost and even freezing on the surface of the evaporator, which in turn will affect The heat exchange efficiency of the evaporator. For this reason, the refrigeration control method of the embodiment of the present invention prevents the evaporator from freezing at a low temperature by the following steps, and lowering the compressor frequency at an appropriate timing can raise the evaporation temperature.

Fig. 5 is a schematic view showing a cooling control method of an air conditioner according to an embodiment of the present invention. As shown in FIG. 5, the refrigeration control method of the present invention may include the following steps:

Step S502, when the air conditioner is operating in the cooling mode, detecting the indoor target temperature Ta (set by the user), the indoor ambient temperature Tb, the outdoor ambient temperature Tc, and the coil temperature of the two

evaporators

551, 552, which are lower in the two coil temperatures. The temperature value is recorded as Td. The above temperature can be detected by a temperature sensor.

Step S504, detecting the on state of the two

fans

410, 420, that is, determining that the air conditioner indoor unit has turned on several fans. If both

fans

410, 420 are turned on, step S506 is performed. If only one fan is turned on, step S508 is performed.

In step S506, the operating frequency of the compressor 510 is determined according to the temperature range in which Td is located and the values of Ta, Tb, and Tc.

Step S508, determining the operating frequency of the compressor 510 according to the temperature difference range in which the Tb-Ta is located and the values of Ta, Tb, and Tc.

Fig. 6 is a flow chart showing a cooling control method of an air conditioner according to an embodiment of the present invention. In some embodiments, the air conditioner is in a cooling mode and can be controlled using the following steps.

Step S601, when the air conditioner is operating in the cooling mode, detecting the indoor target temperature Ta (set by the user), the indoor ambient temperature Tb, the outdoor ambient temperature Tc, and the coil temperatures of the two

evaporators

551, 552, which are lower in the two coil temperatures. The temperature value is Td.

Step S602, detecting the on state of the two

fans

410, 420, that is, determining that the air conditioner indoor unit has turned on several fans. If both of the

fans

410, 420 are turned on, step S604 is performed. If only one fan is turned on, step S609 is performed.

In step S604, it is determined whether Td>T2 is established. If yes, step S605 is performed, and if not, step S606 is performed.

In step S605, Td>T2 is established. The compressor 510 is controlled to operate in a variable frequency, and the frequency f = f (Ta, Tb, Tc). That is, the frequency f is a function of Ta, Tb, Tc. The basic idea is to increase the frequency f of the compressor 510 as the temperature difference between Tb and Ta increases, and increase as the Tc increases. The specific calculation method is the same as the calculation method of the compressor frequency in which only one fan and one evaporator are set in the prior art, and will not be described in detail herein.

In step S606, it is determined whether T1 ≤ Td ≤ T2 is satisfied. If yes, step S607 is executed, and if not, step S608 is not established.

In step S607, T1 ≤ Td ≤ T2 is established. The compressor 510 is controlled to operate at a constant frequency, and the frequency f=f(Ta1, Tb1, Tc1), where Ta1, Tb1, and Tc1 are the indoor target temperature, the indoor ambient temperature, and the outdoor ambient temperature when Td falls to T2, respectively. Since Td has reached or exceeded T1, compressor 510 is required to maintain the frequency so that the coil temperature does not continue to decrease.

In step S608, T1 ≤ Td ≤ T2 is not established, that is, Td < T1 is established. The compressor 510 is controlled to operate down frequency such that its frequency f < f (Ta1, Tb1, Tc1). Therefore, when Td < T1, the coil temperature is already too low, and in order to avoid further decrease in evaporation pressure and evaporation temperature, the compressor 510 needs to be down-converted as soon as possible.

In the above steps, the skilled person can determine the values of T1 and T2 by experiments, for example, such that T1 = 0 ° C and T2 = 4 ° C.

In the above steps, since both of the

fans

410, 420 are operated, both of the

evaporators

551, 552 can obtain good heat exchange. The frequency of the compressor 510 is corrected based on the coil temperature of the

evaporators

551, 552 so that the air conditioner satisfies both the cooling demand and the

evaporator

551, 552 from freezing.

In step S609, when only one fan is turned on, the operating frequency of the compressor 510 is determined according to the temperature difference range in which Tb-Ta is located and the values of Ta, Tb, and Tc. Specifically, the frequency correction coefficient b = b (Tb - Ta) is calculated based on the temperature difference Tb - Ta, and the operating frequency f = b * f (Ta, Tb, Tc) of the compressor 510 is controlled, where b < 1.

Specifically, the value of b can be determined according to the temperature interval in which Tb-Ta is located. When Tb-Ta<T3, b=b1; when T3≤Tb-Ta≤T4, b=b2; when Tb-Ta>T4, b=b3, where b1<b2<b3. In some embodiments, T3 = 7 ° C, T4 = 13 ° C, b1 = 0.5, b2 = 0.8, and b3 = 0.9.

In the above embodiment, when only one fan is operated, in order to prevent the heat of the evaporator portion not covered by the wind of the fan from being unfavorably caused to cause the temperature to be too low, the above embodiment reduces the operating frequency of the compressor 510 by making b<1, Avoid low temperature freezing of this part of the evaporator.

Figure 7 is a schematic block diagram of a refrigeration control apparatus for an inverter air conditioner according to an embodiment of the present invention. The control device 15 of the present embodiment may include a memory 151 and a processor 153, wherein the memory 151 stores therein a control program 152 for performing refrigeration control of the inverter air conditioner of any of the above embodiments when executed by the processor 153. method.

In this regard, it will be appreciated by those skilled in the <RTIgt;the</RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; The content directly determines or derives many other variations or modifications consistent with the principles of the invention. Therefore, the scope of the invention should be understood and construed as covering all such other modifications or modifications.

Claims

A cooling control method for an inverter air conditioner, wherein the indoor unit of the air conditioner includes two evaporators arranged in parallel, two fans respectively corresponding to two of the evaporators, and each of the fans corresponds to at least one air outlet. The refrigeration control method includes:

When the inverter air conditioner is operated in the cooling mode, detecting the indoor target temperature Ta, the indoor ambient temperature Tb, the outdoor ambient temperature Tc, and the coil temperatures of the two evaporators, the lower temperature values of the two coil temperatures are Td;

Detecting an open state of two of the fans;

If both of the fans are turned on, determining the operating frequency of the compressor of the inverter air conditioner according to the temperature range in which Td is located and the values of Ta, Tb, and Tc;

If only one of the fans is turned on, the operating frequency of the compressor is determined according to the temperature difference range in which Tb-Ta is located and the values of Ta, Tb, and Tc.
The refrigeration control method according to claim 1, wherein

When both of the fans are turned on, the operating frequency of the compressor is determined as follows:

When Td>T2, the variable frequency operation of the compressor is controlled, and the running frequency f=f(Ta, Tb, Tc);

When T1≤Td≤T2, the compressor is controlled to operate at a constant frequency, and the running frequency f=f(Ta1, Tb1, Tc1), where Ta1, Tb1 and Tc1 are indoor target temperatures and indoors when Td falls to T2, respectively. Ambient temperature and outdoor ambient temperature;

When Td < T1, the compressor is controlled to be down-converted to have a frequency f < f (Ta1, Tb1, Tc1).
The refrigeration control method according to claim 2, wherein

When only one of the fans is turned on, the operating frequency of the compressor is determined as follows:

The frequency correction coefficient b=b(Tb-Ta) is calculated according to the temperature difference Tb-Ta, and the operating frequency f=b*f(Ta, Tb, Tc) of the compressor is controlled, where b<1.
The refrigeration control method according to claim 3, wherein

When Tb-Ta<T3, b=b1;

When T3≤Tb-Ta≤T4, b=b2;

When Tb-Ta>T4, b=b3, where b1<b2<b3.
The refrigeration control method according to claim 4, wherein

T1 = 0 ° C, T2 = 4 ° C, T3 = 7 ° C, T4 = 13 ° C, b1 = 0.5, b2 = 0.8, b3 = 0.9.
The refrigeration control method according to claim 1, wherein

The air conditioner includes the compressor, a condenser, a tee, a first electronic expansion valve, and a second electronic expansion valve, and two of the evaporators;

An inlet of the three-way pipe is connected to an outlet of the condenser, and two outlets of the three-way pipe respectively communicate with an inlet of the first electronic expansion valve and the second electronic expansion valve;

The outlets of the first electronic expansion valve and the second electronic expansion valve respectively communicate with the inlets of the two evaporators;

Two of the evaporator outlets are respectively connected to the inlet of the compressor.
The refrigeration control method according to claim 1, wherein each of said air outlets is provided with:

a vertical swinging blade group comprising a plurality of vertical pendulum blades extending vertically and mounted at the air outlet, the plurality of vertical pendulum blades being synchronously pivoted to adjust a left-right direction of the wind; and

The yaw group includes a plurality of yaw blades extending horizontally, which are mounted behind the yaw leaves, and the plurality of yaw leaves are synchronously pivoted to adjust the up and down direction of the wind.
The refrigeration control method according to claim 1, wherein

One of the fans corresponds to two of the air outlets, and the other of the fans corresponds to one of the air outlets;

The three outlets are arranged in a straight line.
The refrigeration control method according to claim 1, wherein

Both of the fans are cross-flow fans.
The refrigeration control method according to claim 1, wherein

Both of the evaporators are finned evaporators and share the same set of fins, the coils of the two evaporators respectively matching the two halves of the set of fins.
A refrigeration control apparatus for an inverter air conditioner, comprising: a memory and a processor, wherein the memory stores a control program, and the control program is executed by the processor to implement the method according to any one of claims 1 to 10. The refrigeration control method of the inverter air conditioner.