JPH08226721A - Operation controller for air conditioning equipment for multiple room - Google Patents

Abstract

PURPOSE: To shorten a time required for a refrigerating cycle to stabilize at the start of operation by suppressing possible drop in the capacity under frosting in the heating operation by protecting a compressor overloaded in the cooling operation 7 air conditioning equipment for multiple rooms. CONSTITUTION: When the opening of an electric expansion valve 4 of an outdoor unit X for driving a plurality of room units A-F is controlled by an opening control means 14 in accordance with the degree of overheating, an opening correction means 15 is provided to stop the control of the opening of the opening control means 14 under overloading in the cooling operation and the opening of the electric expansion valve 4 is opened and held to a specified value to protect a compressor by lowering the degree of overheating. When the set value of the degree of overheating is lowered and set to control the opening by the opening control means 14 based on the set value, the same result is obtained too. The same means are used to counter frosting during the heating operation. Moreover, initial opening setting means 16 is provided to set the opening of the electric expansion valve at the start of operation corresponding to the outdoor air temperature, the operation frequency of the compressor and the number of outdoor units, thereby achieving a shortening of time to stabilize a refrigerating cycle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation control device for a multi-room air conditioner in which a plurality of indoor units are connected to one outdoor unit and a refrigerant flow rate is controlled by an electric expansion valve.

[0002]

2. Description of the Related Art In recent years, air conditioners have become widespread, but a multi-room air conditioner that requires only one outdoor unit is an effective device in terms of installation space.

A conventional operation control device for a multi-room air conditioner will be described below. Conventionally, this type of multi-room air conditioner has been constructed such that one outdoor unit equipped with a variable capacity compressor (hereinafter simply referred to as a compressor) is provided to a plurality of indoor units via a branch unit or directly. An electric expansion valve is provided as a throttle device for the refrigeration cycle of the unit, and the above electric expansion is performed so that the superheat value of the refrigerant sucked into the compressor detected by using a temperature sensor, etc. becomes a constant value. The refrigeration cycle was adjusted by controlling the valve opening (hereinafter referred to as superheat control).

Further, since the degree of superheat cannot be detected at the start of operation, the opening degree of the electric expansion valve before the superheat degree control is started is set to the maximum opening degree or a predetermined opening degree of the electric expansion valve. The superheat control was started from the opening.

[0005]

In such a conventional multi-room air conditioner, when the outdoor temperature is high and the operating frequency of the compressor is high in the cooling operation, that is, when it is operated under an overload condition. Also, since the electric expansion valve opening is controlled so that the degree of superheat of the compressor becomes constant, the pressure rises and the temperature of the refrigerant discharged from the compressor also rises. It was a factor that shortened the life.

Also, in the heating operation, when the outdoor temperature is low and the operating frequency of the compressor is high, that is, when the outdoor heat exchanger is operated under a condition where frost is likely to occur,
Since the electric expansion valve opening is controlled so that the superheat of the compressor becomes constant, the electric expansion valve opening becomes smaller as the superheat of cooling starts to decrease due to frost, which further increases frost. However, there is a problem that the heating capacity drops sharply.

Further, since the degree of superheat cannot be detected at the start of operation, the first electric expansion valve opening before entering the superheat control is set to the maximum opening of the electric expansion valve or a predetermined opening. Therefore, there is a problem that it may take a considerable time until the refrigerant superheat reaches a target value and the refrigeration cycle stabilizes under various operating conditions such as indoor load and outdoor temperature. .

The present invention solves the above-mentioned problems, and maintains a normal refrigeration cycle even during cooling overload operation, and slows the frost formation on the outdoor heat exchanger when the heating temperature is low, thereby increasing the heating capacity rapidly. Prevents the decrease and shortens the time until the refrigeration cycle stabilizes for all operating conditions,
It is an object of the present invention to provide an operation control device for a multi-room air conditioner, which has high equipment reliability and improved comfort.

[0009]

The invention according to claim 1 relates to an outdoor unit comprising a compressor, an outdoor heat exchanger, an outdoor fan, a four-way valve, an electric expansion valve provided in a liquid side main pipe, and a refrigerant branch. A refrigeration cycle is configured by connecting a plurality of indoor units including an indoor heat exchanger and a blower through a unit or directly to detect the refrigerant refrigerant intake temperature and the low pressure equivalent pressure saturation temperature. , The temperature difference, that is, the degree of superheat of the refrigerant sucked into the compressor, in a multi-room air conditioner having an opening control means for controlling the opening of the electric expansion valve so as to be a predetermined set value, When the outdoor temperature is higher than a predetermined value during the cooling operation and the operating frequency of the compressor is higher than the predetermined value, the control of the opening control means is disabled and the opening of the electric expansion valve is opened to a predetermined value. To set The invention according to claim 2 is provided in the compressor, the outdoor heat exchanger, the outdoor fan, the four-way valve, and the liquid side main pipe. An outdoor unit such as an electric expansion valve is connected to a plurality of indoor units such as an indoor heat exchanger and a blower via a refrigerant branching unit or directly to form a refrigeration cycle, and a refrigerant sucked into the compressor. The temperature and the low pressure equivalent to the pressure saturation are detected, and the opening of the electric expansion valve is controlled so that the temperature difference, that is, the superheat degree of the refrigerant sucked into the compressor becomes a predetermined first set value. In a multi-room air conditioner having an opening degree control means, when the outdoor air temperature is higher than a predetermined value during cooling operation and the operating frequency of the compressor is higher than a predetermined value, the superheat setting value is set to Lower than the set value of 1 An operation control device for a multi-room air conditioner, comprising an opening correction means for changing to a second predetermined set value, and the invention according to claim 3 is a compressor, an outdoor heat exchanger, an outdoor fan, A refrigeration cycle in which a plurality of indoor units such as indoor heat exchangers and blowers are connected to an outdoor unit including a four-way valve and an electric expansion valve provided in the liquid side main pipe, directly or through a refrigerant branching unit. And a temperature corresponding to the pressure saturation of the low pressure of the compressor is detected, and the temperature difference, that is, the degree of superheat of the suction refrigerant of the compressor is set to a predetermined set value by the electric expansion. In a multi-room air conditioner having an opening control means for controlling the opening of a valve, when the outdoor air temperature is lower than a predetermined value during heating operation and the operating frequency of the compressor is higher than a predetermined value, the opening control is performed. Disable control of means In addition, the invention relates to an operation control device for a multi-room air conditioner, which is provided with an opening degree correction means for setting the opening degree of the electric expansion valve to a predetermined opening degree.
An indoor unit such as a compressor, an outdoor heat exchanger, an outdoor fan, a four-way valve, and an electric expansion valve provided on the liquid side main pipe, through a refrigerant branch unit, or directly from an indoor heat exchanger and a blower. A plurality of indoor units are connected to form a refrigeration cycle, and the refrigerant suction temperature of the compressor and the pressure saturation equivalent temperature of low pressure are detected, and the temperature difference, that is, the degree of superheat of the refrigerant suction of the compressor, In a multi-room air conditioner provided with an opening control means for controlling the opening of the electric expansion valve so as to have a predetermined first set value,
When the outdoor air temperature is lower than the predetermined value and the operating frequency of the compressor is higher than the predetermined value during the heating operation, the opening degree control unit is disabled and the superheat degree setting value is lower than the first setting value. An operation control device for a multi-room air conditioner, comprising an opening correction means for changing to a second predetermined set value, and
According to a fifth aspect of the present invention, an outdoor unit including a compressor, an outdoor heat exchanger, an outdoor fan, a four-way valve, an electric expansion valve provided in a liquid side main pipe, or the like is provided directly or via a refrigerant branching unit. A plurality of indoor units including an indoor heat exchanger and a blower are connected to form a refrigeration cycle, and a suction refrigerant temperature of the compressor and a low-pressure pressure saturation equivalent temperature are detected, and the temperature difference, that is, the compressor. In the multi-chamber air conditioner having an opening degree control means for controlling the opening degree of the electric expansion valve so that the degree of superheat of the suction refrigerant becomes a predetermined set value. An initial opening setting means for setting an initial opening is provided, and the initial opening setting means determines the initial opening of the electric expansion valve based on a condition at the time of starting operation. The operation control device of The invention according to claim 6 is the operation control device for a multi-room air conditioner according to claim 5, wherein the initial opening setting means determines the opening of the electric expansion valve according to the operating frequency of the compressor. The invention according to claim 7 is the operation control device for a multi-room air conditioner according to claim 5, wherein the initial opening setting means determines the initial stage of the electric expansion valve according to the outdoor temperature. And claim 8
The invention according to claim 5 is characterized in that the initial opening setting means determines the initial opening of the electric expansion valve according to two factors of the operating frequency of the compressor and the outdoor temperature. The operation control device according to claim 9, and the invention according to claim 9 is characterized in that the initial opening setting means determines the initial opening of the electric expansion valve according to the total number of connected indoor units. It is an operation control device of the multi-room air conditioner described.

[0010]

In the invention according to claim 1, in the cooling operation, when the outdoor temperature is high and the operating frequency of the compressor is high, that is, when the compressor is operated under an overload condition, the opening correction means is the opening control means. The opening degree control by means of (1) is stopped, and the opening degree of the electric expansion valve is opened and maintained to a predetermined value. When operating in this state, the high pressure and discharge temperature are reduced, improving the reliability and life of the compressor. Further, in the invention according to claim 2, in the cooling operation, when the outdoor temperature is high and the operating frequency of the compressor is high, that is, when the compressor is operated under an overload condition, the opening degree correction means sets the superheat degree set value to a low value. Set to the value. When operated under the control of the opening control means in this state, the high pressure and the discharge temperature are lowered, and the reliability and life of the compressor are improved. Further, in the inventions according to claims 3 and 5, in the heating operation, when the outdoor air temperature is low and the operating frequency of the compressor is high, that is, when the outdoor heat exchanger is operated under a condition where frost easily occurs, The opening correction means stops the opening control by the opening control means,
The opening of the electric expansion valve is opened and maintained to a predetermined value. When operating in this state, the low pressure rises and suppresses the growth of frost,
Prevent a sudden decrease in heating capacity. Further, in the invention according to claim 4, during heating operation, when the outdoor temperature is low and the operating frequency of the compressor is high, that is, when the outdoor heat exchanger is operated under the condition that frost is likely to occur, the opening degree correction means Sets the superheat setting value to a low predetermined value. When operating under the control of the opening degree control means in this state, the opening degree of the electric expansion valve widens, and like the above, a sudden decrease in heating capacity is prevented. Further, in the invention according to claims 5 to 8, the initial value setting means sets the first electric expansion valve opening degree at the start of operation to the operating frequency of the compressor, the outdoor temperature,
Alternatively, according to the two factors of the operating frequency and the outdoor temperature, or the total number of connected indoor units, a predetermined opening is set so that the refrigeration cycle is stable with respect to the operating condition, The refrigeration cycle can reach a stable state in a short time even for operating conditions, and improve comfort.

[0011]

【Example】

(Embodiment 1) An embodiment of the operation control device for a multi-room air conditioner of the present invention will be described below with reference to the drawings. FIG. 1 is a refrigeration cycle diagram showing the configuration of this embodiment. In the figure, X is an outdoor unit, Y1 and Y2 are branching units, and A to F are indoor units.
The outdoor unit X includes a variable frequency compressor 1, an outdoor heat exchanger 2, a four-way valve 3 for switching between heating and cooling, and an electric expansion valve 4. Two branch units Y1 and Y2 are connected to the outdoor unit X via connection pipes 5 and 6, respectively, and the branch unit Y1 has three electric expansion valves 7a and 7a.
b and 7c are provided, and similarly, the branch unit Y2 is also provided with electric expansion valves 7d, 7e, and 7f. The branch unit Y1 has three indoor units A and B,
And C, and the branch unit Y2 is also connected to the three indoor units D, E, and F to form a refrigeration cycle. Note that 8a to 8f are indoor heat exchangers provided in the indoor units A to F, respectively. Also, 14
Is an opening control means for controlling the opening of the electric expansion valve, 15 is an opening correction means for correcting the opening of the electric expansion valve, and 16 is an initial opening for setting the initial opening of the electric expansion valve at the start of operation. Setting means, which constitute the operation control device of the multi-room air conditioner of the present invention.

The flow of the refrigerant in the above structure will be described. During the cooling operation, the high-pressure gas refrigerant discharged from the compressor 1 passes through the four-way valve 3, is heat-exchanged in the outdoor heat exchanger 2 to become a high-pressure liquid refrigerant, and is throttled by the electric expansion valve 4 to be a low-pressure liquid refrigerant. It becomes a refrigerant. Next, the water is branched into two in the outdoor unit X, and flows to the branch unit Y2 via the connection pipe 5 and the branch unit Y1 and the connection pipe 6. Next, in the branch unit Y1, the liquid refrigerant is branched into three so as to have an appropriate flow rate according to the opening degree of the electric expansion valves 7a, 7b, 7c, and heat is exchanged by the indoor heat exchangers 8a, 8b, 8c, respectively. It is turned into gas and returns to the branch unit Y1. The same applies to the branch unit Y2. 2 in the outdoor unit X
The gas refrigerants returning from the branch unit of the stand join together and then return to the compressor 1 through the four-way valve 3. Reference numeral 9 denotes a bypass passage that connects the intermediate portion between the electric expansion valve 4 and the outdoor heat exchanger 2 to the suction pipe 10. A capillary tube 11 is provided in the middle of the bypass passage, and the refrigerant temperature on the suction pipe 10 side of the bypass passage 9 is shown. A temperature sensor 12 for detecting the temperature is provided, and its temperature is equal to the low-pressure saturation temperature. Further, the suction pipe 10 is also provided with a temperature sensor 13 for detecting the temperature of the suction refrigerant. The opening control means 14 includes a temperature sensor 12
The detection outputs of 13 and 13 are input, the temperature difference, that is, the superheat degree of the refrigerant sucked into the compressor 1 is calculated, and the opening degree control of the electric expansion valve 4 is performed based on the result, and the opening degree correction means 15 Corrects the operation of the electric expansion valve when there is a possibility of frost formation during cooling or during heating, and the initial opening setting means 16 sets the initial opening of the electric expansion valve at the start of operation. To do. The initial opening degree setting means 16 will be described in a later-described embodiment and will not be described in this embodiment.

The operation of the above structure will be described with reference to the drawings. In FIG. 2, the solid line is a characteristic diagram showing the relationship between the opening degree of the electric expansion valve 4 and the degree of superheat during cooling in the present embodiment over time. First, the opening degree of the electric expansion valve 4 at the start of operation starts from the maximum, and the opening degree control means 1
4, the opening degree of the electric expansion valve 4 is narrowed by several pulses so that the target degree of superheat degree (here, set to 7 deg) is reached. Stable while making fine adjustments to a constant value of 7deg,
The optimum refrigeration cycle is reached after Δt time. At the time point indicated by point A in the figure, the outdoor temperature is high, for example, 39
When the operating frequency of the compressor 1 at that time is high at ℃ or higher, for example, the operable frequency of the compressor is 30 to 90 Hz.
If it is a condition of 80 Hz or more, the above superheat control is stopped, and the opening correction means 15 causes the opening of the electric expansion valve 4 to be close to the maximum value and a predetermined opening at which liquid back does not occur. Open and set up, and in that state the opening control means 1
When operated without the control of No. 4, as shown in the figure, the degree of superheat rapidly decreases corresponding to the widened opening, and it is possible to suppress excessive rise of high pressure.

As described above, according to the operation control device for a multi-room air conditioner of this embodiment, when the outdoor temperature is high and the operating frequency of the compressor 1 is higher than a predetermined value, an overload condition occurs. Therefore, the superheat control is temporarily stopped and the electric expansion valve is opened to a predetermined value, whereby the high pressure can be prevented from rising too much and the compressor can be protected.

Needless to say, it is possible to return to the opening control by the opening control means 14 after eliminating the overload condition.

(Embodiment 2) An embodiment of the operation control device for a multi-room air conditioner of the invention according to claim 2 will be described below. The refrigeration cycle diagram showing the configuration of the present embodiment is the same as that in FIG. 1, and detailed description thereof will be omitted. The present embodiment differs from the first embodiment in the operation of the opening degree correction means 15. In the present embodiment, the opening degree correction means 15 changes the set value of the superheat degree from 7 deg to 2 deg as shown by the broken line in FIG. To set. Since the opening degree control means 14 controls the electric expansion valve 4 with this newly set superheat degree set value as a target, the opening degree of the electric expansion valve 4 widens by several pulses as shown by the broken line in the figure. Correspondingly, the superheat gradually decreases and then stabilizes. In this way, the rise in high pressure is suppressed.

As described above, according to the operation control apparatus for a multi-room air conditioner of this embodiment, when the outdoor temperature is high during the cooling operation and the operating frequency of the compressor becomes higher than a predetermined value, By changing the set value of the superheat degree to a value lower than normal by the opening degree correction means and setting it, and by controlling the opening degree based on the changed superheat degree set value, it is possible to prevent the high pressure from rising too high. The compressor can be protected.

Needless to say, after the overload condition is eliminated, the opening degree control may be returned to the normal opening degree control value.

(Embodiment 3) An embodiment of an operation control device for a multi-room air conditioner according to claim 3 will be described below with reference to the drawings. The refrigeration cycle diagram showing the configuration of the present embodiment is the same as that in FIG. 1, and detailed description thereof will be omitted. The description of the operation in the normal state is also omitted. Although the first and second embodiments relate to the operation during the cooling operation, the present embodiment relates to the operation of the opening degree correction unit 15 during the heating operation. The solid line in FIG. 3 shows the relationship between the opening degree of the electric expansion valve 4 and the low pressure during heating according to the present embodiment with a change over time. In normal operation, the opening degree of the electric expansion valve 4 is controlled by the opening degree control means 14 so that the degree of superheat becomes a predetermined set value, and is stabilized. Now, at the point B in the figure, when the outdoor temperature is low, for example, at 4 ° C. or lower and the operating frequency of the compressor 1 at that time is high, for example, assuming that the operable frequency of the compressor is 30 to 90 Hz, it becomes 80 Hz or more. If it is a condition, the degree of superheat control by the opening degree control means 14 is temporarily stopped, and the opening degree correction means 15 does not cause a liquid back at a predetermined opening degree, that is, the expansion valve opening degree, and significantly lowers the heating capacity. Set an opening that does not reach and operate in that state. As a result, as shown by the solid line in the figure, overthrottle by the electric expansion valve 4 is eliminated and the low pressure rises rapidly. Therefore, an increase in the amount of frost formed on the outdoor heat exchanger 2 can be prevented, and a rapid decrease in heating capacity can be prevented.

As described above, according to this embodiment, when the outdoor air temperature is lower than the predetermined value and the operating frequency of the compressor is higher than the predetermined value during the heating operation, the opening correction means 15 opens the opening of the electric expansion valve. By opening to a predetermined value, it is possible to prevent the low pressure from rising and prevent an increase in frost formation on the outdoor heat exchanger, and prevent the heating capacity from decreasing.

Needless to say, the control by the opening control means may be returned to after the frosting and the reduction of the heating capacity are eliminated.

(Embodiment 4) An embodiment of the invention according to claim 4 will be described below with reference to the drawings. The refrigeration cycle diagram showing the configuration of the present embodiment is the same as that in FIG. 1, and detailed description thereof will be omitted. The description of the operation in the normal state is also omitted. This embodiment is the third embodiment.
The difference is in the operation of the opening degree correction means 15. The broken line in FIG. 3 shows the relationship between the opening degree of the electric expansion valve 4 and the low pressure in this embodiment as a function of time. When the low temperature condition similar to that of the third embodiment is obtained at the point B, the opening correction means 15 changes the set value of the superheat degree from the first set value of 7 deg to 2 deg.
By controlling according to the new superheat degree set value by the opening degree control means 14, the opening degree of the electric expansion valve 4 is expanded by several pulses, a decrease in low pressure can be prevented, and a significant decrease in heating capacity can be prevented as described above. There is.

As described above, according to this embodiment, when the outdoor air temperature is lower than the predetermined value and the operating frequency of the compressor is higher than the predetermined value during the heating operation, the opening degree correcting means lowers the superheat degree setting value. By setting the above, it is possible to prevent a decrease in heating capacity due to a decrease in low pressure.

(Embodiment 5) An embodiment of the invention according to claims 5 and 6 will be described below with reference to the drawings. The refrigeration cycle diagram showing the configuration of the present embodiment is the same as that of FIG. 1, and detailed description thereof will be omitted. However, in the present embodiment, the initial opening setting means 16 opens the electric expansion valve at the start of operation. The degree is set. The opening change of the electric expansion valve shown by the alternate long and short dash line in Fig. 2 is shorter than before by stabilizing the refrigeration cycle by changing the initial opening at the start of operation using the operating frequency of the compressor as a parameter. In this case, Δt becomes Δt ′. FIG.
FIG. 6 is a characteristic diagram showing a relationship when the initial opening degree is changed according to the operating frequency of the compressor in this way. As shown in the figure, in consideration of the fact that the higher the operating frequency is, the larger the opening degree of the expansion valve at the time of stability is, the initial opening degree is increased corresponding to the operating frequency.

As described above, according to this embodiment, the initial opening degree setting means changes the initial opening degree of the electric expansion valve in accordance with the operating frequency of the compressor. By setting a large value, the time until the refrigeration cycle stabilizes can be shortened and the function as an air conditioner improves.

(Embodiment 6) An embodiment of the invention according to claims 5 and 7 will be described below. The present embodiment differs from the fifth embodiment in that the initial opening setting means 16 sets the initial opening of the electric expansion valve according to the outdoor temperature. FIG. 5 is a characteristic diagram showing the relationship between the outdoor temperature and the initial opening in this embodiment. Since the higher the outdoor temperature, the higher the degree of superheat, the initial opening can be increased and the time required for the refrigeration cycle to stabilize can be shortened.

As described above, according to this embodiment, the initial opening degree setting means 16 changes the initial opening degree of the electric expansion valve so that the higher the outdoor temperature is, the larger the initial opening degree is set. The time until the refrigeration cycle stabilizes can be shortened and the function as an air conditioner improves.

(Embodiment 7) An embodiment of the invention according to claims 5 and 8 will be described below. This embodiment is different from the fifth and sixth embodiments in that the initial opening setting means 1
6 is that the initial opening degree of the electric expansion valve is set by the two factors of the operating frequency of the compressor and the outdoor temperature.
FIG. 6 is a characteristic diagram showing the relationship. As described in the fifth and sixth embodiments, the initial opening degree of the electric expansion valve can be set large for both the operating frequency of the compressor and the outdoor temperature. The higher the machine frequency and the outdoor temperature, the larger the initial opening of the electric expansion valve is set.The range of the operating frequency and the outdoor temperature is divided into blocks, and the initial opening is assigned to each block. By doing so, the time until the refrigeration cycle stabilizes can be further shortened.

As described above, according to this embodiment, the initial opening degree setting means 16 changes the initial opening degree of the electric expansion valve in accordance with the operating frequency of the compressor and the outdoor temperature. By setting a large initial opening, the time until the refrigeration cycle stabilizes can be further shortened.

(Embodiment 8) An embodiment of the invention according to claims 5 and 7 will be described below. In the present embodiment, the initial opening degree setting means 16 determines the initial opening degree of the electric expansion valve in accordance with the total number of connected indoor units. FIG. 7 is a characteristic diagram showing the relationship between the total number of indoor units and the initial opening of the electric expansion valve in this embodiment. When the number of connected indoor units is small, the amount of refrigerant in the refrigeration cycle becomes excessive, it is difficult to achieve superheat, and the expansion valve opening becomes small when the refrigeration cycle stabilizes. By setting the degree small, the stability of the refrigeration cycle can be accelerated regardless of the installation condition of the indoor unit.

As described above, according to this embodiment, the initial opening setting means 16 changes the initial opening of the electric expansion valve in accordance with the total number of indoor units. By setting the initial opening degree of 2 small, the time until the refrigeration cycle stabilizes can be shortened.

[0032]

As is apparent from the above embodiments, the invention according to claim 1 comprises a compressor, an outdoor heat exchanger, an outdoor fan, a four-way valve, and an electric expansion valve provided in the liquid side main pipe. A refrigeration cycle is configured by connecting a plurality of indoor units including an indoor heat exchanger and a blower to an outdoor unit via a refrigerant branching unit or directly to construct a refrigeration cycle, and the suction refrigerant temperature of the compressor and low pressure saturation. A multi-chamber having an opening control means for detecting an equivalent temperature and controlling the opening of the electric expansion valve so that the temperature difference, that is, the degree of superheat of the refrigerant sucked into the compressor becomes a predetermined set value. In the air conditioner for use, when the outdoor air temperature is higher than a predetermined value during the cooling operation and the operating frequency of the compressor is higher than the predetermined value, the control of the opening control means is invalidated, and the electric expansion valve Opening By providing the opening correction means for setting the opening of the compressor, it is possible to protect the compressor by suppressing overheating and high pressure that occur during cooling overload operation, and the invention according to claim 2 , An outdoor heat exchanger, an outdoor fan, a four-way valve, and an outdoor expansion unit such as an electric expansion valve provided on the liquid side main pipe, and an indoor heat exchanger and a blower through a refrigerant branch unit or directly. A plurality of indoor units are connected to form a refrigeration cycle, and a suction refrigerant temperature of the compressor and a low pressure equivalent pressure saturation temperature are detected, and the temperature difference, that is, the superheat degree of the suction refrigerant of the compressor is a predetermined value. In a multi-room air conditioner equipped with an opening control means for controlling the opening of the electric expansion valve so that the opening temperature of the electric expansion valve is adjusted to the first set value, the outdoor temperature is higher than a predetermined value during cooling operation, and the compressor is The operating frequency of If it is higher than the value, the opening degree correction means for changing the superheat degree set value to the second predetermined set value lower than the first set value is provided, so that the overheat generated during the cooling overload operation can be prevented. The invention according to claim 3 can protect the compressor by suppressing excessive pressure and high pressure. Further, the invention according to claim 3 includes a compressor, an outdoor heat exchanger, an outdoor fan, a four-way valve, and an electric expansion valve provided in a liquid side main pipe. A plurality of indoor units including an indoor heat exchanger and a blower are connected to an outdoor unit consisting of a refrigerant branching unit or directly to form a refrigeration cycle, and the refrigerant refrigerant suction pressure and low pressure The temperature equivalent to saturation is detected,
The temperature difference, that is, the degree of superheat of the refrigerant sucked into the compressor, in a multi-room air conditioner equipped with an opening control means for controlling the opening of the electric expansion valve so as to reach a predetermined set value, When the outdoor temperature is lower than a predetermined value and the operating frequency of the compressor is higher than the predetermined value during operation, the control of the opening control means is disabled and the opening of the electric expansion valve is set to the predetermined opening. By providing the opening degree correction means for controlling, it is possible to suppress an excessive decrease in low pressure and a decrease in heating capacity. Further, the invention according to claim 4 is a compressor, an outdoor heat exchanger,
Connect multiple indoor units such as an indoor heat exchanger and blower to an outdoor unit consisting of an outdoor fan, a four-way valve, and an electric expansion valve installed in the liquid side main pipe, or directly via a refrigerant branching unit. A refrigerating cycle is configured to detect a refrigerant suction temperature of the compressor and a low pressure equivalent pressure saturation temperature, and the temperature difference, that is, the degree of superheat of the refrigerant suction of the compressor becomes a predetermined first set value. In the multi-room air conditioner having the opening control means for controlling the opening of the electric expansion valve so that the outdoor air temperature is lower than a predetermined value during the heating operation, and the operating frequency of the compressor is higher than the predetermined value. In this case, when the opening degree control means is disabled and the opening degree correction means for changing the superheat degree set value to the second predetermined set value lower than the first set value is provided, the low pressure is lowered. Passage and heating capacity Can the decrease in inhibition, also claim 5
The invention according to claim 8 is to an outdoor unit including a compressor, an outdoor heat exchanger, an outdoor fan, a four-way valve, and an electric expansion valve provided in a liquid side main pipe, via a refrigerant branching unit or directly. , A plurality of indoor units including an indoor heat exchanger and a blower are connected to form a refrigeration cycle, and a suction refrigerant temperature of the compressor and a pressure saturation equivalent temperature of low pressure are detected, and the temperature difference, that is, the compression In a multi-room air conditioner having an opening control means for controlling the opening of the electric expansion valve so that the degree of superheat of the refrigerant sucked into the machine becomes a predetermined set value, the electric expansion valve at the start of operation. By providing an initial opening setting means for setting the initial opening of the electric expansion valve, the initial opening setting means determines the initial opening of the electric expansion valve based on the condition at the start of operation. The initial opening of the valve Operating frequency, the outdoor air temperature of the compressor,
Alternatively, the total number of connected indoor units can be set as a parameter, and the time until the refrigeration cycle stabilizes can be shortened according to the operating condition, and the comfort can be improved.

[Brief description of drawings]

FIG. 1 is a refrigeration cycle diagram showing a configuration of an embodiment of a multi-room air conditioner according to the present invention.

FIG. 2 is a characteristic diagram showing the relationship between the degree of opening and the degree of superheat of the electric expansion valve during cooling in one embodiment of the operation control device for a multi-room air conditioner according to the present invention, as a function of time.

FIG. 3 is a characteristic diagram showing the relationship between the opening degree of the electric expansion valve and the low pressure during heating in one embodiment of the operation control device for a multi-room air conditioner of the present invention, as a function of time.

FIG. 4 is a characteristic diagram showing the relationship between the operating frequency of the compressor and the initial opening degree of the electric expansion valve in the embodiment of the operation control device for the multi-room air conditioner of the present invention.

FIG. 5 is a characteristic diagram showing the relationship between the outdoor temperature and the initial opening degree of the electric expansion valve in an embodiment of the operation control device for a multi-room air conditioner of the present invention.

FIG. 6 is a characteristic diagram showing the relationship between the operating frequency of the compressor, the outdoor air temperature, and the initial opening of the electric expansion valve in the embodiment of the operation control device for a multi-room air conditioner of the present invention.

FIG. 7 is a characteristic diagram showing a relationship between the total number of indoor units and the initial opening degree of the electric expansion valve in the embodiment of the operation control device for the multi-room air conditioner of the present invention.

[Explanation of symbols]

 X outdoor unit Y1, Y2 branch unit A to F indoor unit 1 compressor 2 outdoor heat exchanger 3 four-way valve 4 electric expansion valve 5, 6 connection pipe 8a to 8f indoor heat exchanger 10 intake pipe 12, 13 temperature sensor 14 Opening control means (operation control device) 15 Opening correction means (operation control device) 16 Initial opening setting means (operation control device)

Claims (9)

[Claims] 1. Indoor heat exchange to an outdoor unit including a compressor, an outdoor heat exchanger, an outdoor fan, a four-way valve, and an electric expansion valve provided in a liquid side main pipe, through a refrigerant branch unit or directly. A plurality of indoor units such as an air conditioner and a blower are connected to form a refrigerating cycle, and a refrigerant suction temperature of the compressor and a pressure saturation equivalent temperature of low pressure are detected, and a temperature difference between them, that is, a refrigerant suction of the compressor. In the multi-room air conditioner having an opening degree control means for controlling the opening degree of the electric expansion valve so that the degree of superheat of the electric expansion valve becomes a predetermined set value, the outdoor air temperature is higher than the predetermined value during the cooling operation, and When the operating frequency of the compressor is higher than a predetermined value, the control of the opening control means is invalidated, and an opening correction means for setting the opening of the electric expansion valve to a predetermined opening is provided. Room air conditioner luck Rolling control device. 2. Indoor heat exchange to a outdoor unit including a compressor, an outdoor heat exchanger, an outdoor fan, a four-way valve, and an electric expansion valve provided in a liquid side main pipe, via a refrigerant branch unit or directly. A plurality of indoor units such as an air conditioner and a blower are connected to form a refrigerating cycle, and a refrigerant suction temperature of the compressor and a pressure saturation equivalent temperature of low pressure are detected, and a temperature difference between them, that is, a refrigerant suction of the compressor. In a multi-room air conditioner equipped with an opening control means for controlling the opening of the electric expansion valve so that the superheat degree of is equal to a predetermined first set value, the outdoor air temperature is lower than the predetermined value during the cooling operation. high,
And when the operating frequency of the compressor is higher than a predetermined value,
The superheat degree set value is set to a second value lower than the first set value.
An operation control device for a multi-room air conditioner, comprising an opening degree correction means for changing the setting value to a predetermined set value. 3. The indoor heat exchange to an outdoor unit including a compressor, an outdoor heat exchanger, an outdoor fan, a four-way valve, and an electric expansion valve provided in a liquid side main pipe, through a refrigerant branch unit or directly. A plurality of indoor units such as an air conditioner and a blower are connected to form a refrigerating cycle, and a refrigerant suction temperature of the compressor and a pressure saturation equivalent temperature of low pressure are detected, and a temperature difference between them, that is, a refrigerant suction of the compressor. In the multi-room air conditioner having an opening control means for controlling the opening of the electric expansion valve so that the degree of superheat of the electric expansion valve becomes a predetermined set value, the outdoor air temperature is lower than the predetermined value during the heating operation, and When the operating frequency of the compressor is higher than a predetermined value, the control of the opening control means is invalidated, and the opening degree correction means for setting the opening degree of the electric expansion valve to a predetermined opening degree is provided for the multi-chamber use. Air conditioner operation control apparatus. 4. Indoor heat exchange to a outdoor unit including a compressor, an outdoor heat exchanger, an outdoor fan, a four-way valve, and an electric expansion valve provided in a liquid side main pipe, through a refrigerant branch unit or directly. A plurality of indoor units such as an air conditioner and a blower are connected to form a refrigerating cycle, and a refrigerant suction temperature of the compressor and a pressure saturation equivalent temperature of low pressure are detected, and a temperature difference between them, that is, a refrigerant suction of the compressor. In a multi-room air conditioner equipped with opening control means for controlling the opening of the electric expansion valve so that the degree of superheat of the electric expansion valve becomes a predetermined first set value, the outdoor air temperature is higher than a predetermined value during heating operation. Low,
In addition, when the operating frequency of the compressor is higher than a predetermined value, the opening degree control means is disabled and the degree of superheat setting value is changed to a second predetermined setting value lower than the first setting value. An operation control device for a multi-room air conditioner having a correction means. 5. Indoor heat exchange to a outdoor unit including a compressor, an outdoor heat exchanger, an outdoor fan, a four-way valve, an electric expansion valve provided in a liquid side main pipe, etc. via a refrigerant branch unit or directly. A plurality of indoor units such as an air conditioner and a blower are connected to form a refrigerating cycle, and a refrigerant suction temperature of the compressor and a pressure saturation equivalent temperature of low pressure are detected, and a temperature difference between them, that is, a refrigerant suction of the compressor. In a multi-room air conditioner having an opening control means for controlling the opening of the electric expansion valve so that the degree of superheat of the electric expansion valve becomes a predetermined set value, the first opening of the electric expansion valve at the start of operation. Control means for the multi-room air conditioner, in which an initial opening degree setting means for setting the degree of opening is provided, and the initial opening degree setting means determines the initial opening degree of the electric expansion valve based on the condition at the time of starting operation. apparatus. 6. The operation control device for a multi-room air conditioner according to claim 5, wherein the initial opening setting means determines the opening of the electric expansion valve according to the operating frequency of the compressor. 7. The operation control device for a multi-room air conditioner according to claim 5, wherein the initial opening setting means determines the initial stage of the electric expansion valve according to the outdoor temperature. 8. The multi-room air conditioner according to claim 5, wherein the initial opening setting means determines the initial opening of the electric expansion valve according to two factors of the operating frequency of the compressor and the outdoor temperature. Operation control device. 9. The operation control device for a multi-room air conditioner according to claim 5, wherein the initial opening setting means determines the initial opening of the electric expansion valve according to the total number of connected indoor units. .