JP2009198040A - Operation control method of multi-chamber type air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an operation control method of a multi-chamber type air conditioner which is properly operable without impairing the reliability of a compressor. <P>SOLUTION: This operation control method is composed of the compressor 1, an accumulator 14, an outdoor air blower 5, an outdoor heat exchanger 4, an outdoor unit 21 provided with an expansion valve 8, and a plurality of indoor units 22 connected to the outdoor unit 21 and incorporated with an indoor heat exchanger 9 and an indoor air blower 10, and has a liquid bypass circuit 3 for connecting an outlet of the outdoor heat exchanger 4 and the accumulator 14 by a bypass via a second expansion valve 7a. When an operation frequency of the compressor 1 is a preset frequency or higher in cooling or heating operation, when the delivery temperature of the compressor 1 exceeds a first preset value, an opening of the second expansion valve 7a is set to a first preset opening, and when exceeding a second preset value, an opening of the second expansion valve 7a is set to a second preset opening, so that proper cooling or heating operation can be performed by preventing reduction in compressor low pressure and an excessive rise in the compressor low delivery temperature. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an operation control method for a multi-room air conditioner.

  A conventional operation control method for this type of multi-room air conditioner will be described with reference to FIGS.

  FIG. 17 is a refrigeration cycle diagram showing a conventional multi-room air conditioner operation control method, FIG. 18 is a flowchart showing the multi-room air conditioner operation control method, and FIG. 19 is the multi-room air conditioner. FIG. 20 is a control block diagram showing the operation control method for the multi-room air conditioner.

  In FIG. 17, the conventional multi-room type air conditioner is composed of a single outdoor unit 21 and a plurality of indoor units 22 connected to the outdoor unit 21. The outdoor unit 21 is a variable capacity compressor 1. An accumulator 14, a four-way valve 2, an outdoor heat exchanger 4, an expansion valve 8 that is a pressure reducing device, an outdoor fan 5 that applies outside air to the outdoor heat exchanger 4, and an outside air temperature sensor 6 that detects the outside air temperature. And a liquid bypass circuit 3 that bypasses between the outlet side of the outdoor heat exchanger 4 and the accumulator 14 via the electromagnetic two-way valve 7 and the capillary tube 16.

  The indoor unit 22 includes an indoor heat exchanger 9, an indoor piping temperature sensor 11 that detects the piping temperature of the indoor heat exchanger 9, an indoor suction temperature sensor 12 that detects the indoor temperature, and indoor air through the indoor heat exchanger 9. The compressor 1, the accumulator 14, the four-way valve 2, the indoor heat exchanger 9, the expansion valve 8, and the outdoor heat exchanger 4 are connected in order via a refrigerant pipe 15 and are refrigerated. Constitutes a cycle.

Here, in the cooling or heating operation, when the operation frequency of the compressor 1 is equal to or higher than the set frequency and the discharge temperature of the compressor 1 is detected to be equal to or higher than the set temperature, the electromagnetic two-way valve 7 is opened and the outlet of the outdoor heat exchanger 4 is opened. Since the liquid refrigerant discharged from the refrigerant flows into the accumulator 14, it is possible to prevent an excessive increase in the discharge temperature of the compressor 1 (see, for example, Patent Document 1).
JP-A-8-28982

  However, in the conventional multi-room type air conditioner operation control method, the outlet of the outdoor heat exchanger 4 and the accumulator 14 are connected via the electromagnetic two-way valve 7 and the capillary tube 16, but the liquid refrigerant is not used. However, the loss of capacity is large due to the flow toward the inhalation, and the reliability of the compressor 1 is ensured, but there is a disadvantage that the cooling or heating capacity is insufficient and the user is uncomfortable.

  The present invention solves the above-described conventional problems, and reduces the discharge temperature of the compressor while minimizing a decrease in capacity, and can operate properly without impairing the reliability of the compressor. An object of the present invention is to provide an operation control method.

In order to solve the above-mentioned conventional problems, an operation control method for a multi-room air conditioner according to the present invention includes a compressor, an accumulator, an outdoor blower, an outdoor heat exchanger, an outdoor unit provided with a pressure reducing device, and the outdoor unit. And a plurality of indoor units including an indoor heat exchanger and an indoor blower, and bypass the outlet of the outdoor heat exchanger and the accumulator via a second expansion valve. A liquid bypass circuit is provided, and in cooling or heating operation, when the operating frequency of the compressor is equal to or higher than a set frequency and the discharge temperature of the compressor exceeds the first set value, the second expansion valve is opened. When the discharge temperature exceeds the second set value, the opening of the second expansion valve is set as the second set opening, and the lowering of the compressor low pressure and Compressor low discharge temperature It becomes possible to make a cooling and heating operations.

  The operation control method for a multi-room air conditioner according to the present invention can eliminate a decrease in compressor low pressure during cooling or heating operation, and can prevent a decrease in cooling / heating capacity.

  The first invention includes a compressor, an accumulator, an outdoor fan, an outdoor heat exchanger, an outdoor unit provided with a pressure reducing device, and a plurality of units that are connected to the outdoor unit, and that include an indoor heat exchanger and an indoor fan. A liquid bypass circuit that bypasses the outlet of the outdoor heat exchanger and the accumulator via a second expansion valve, and operates at the operating frequency of the compressor during cooling or heating operation. When the discharge temperature of the compressor exceeds the first set value when the value is equal to or higher than the set frequency, the opening of the second expansion valve is set to the first set opening, and the discharge temperature is set to the second set value. Exceeds the second expansion valve, the opening of the second expansion valve is set to the second set opening, which prevents a decrease in the low pressure of the compressor and an excessive increase in the low discharge temperature of the compressor, and at the same time an appropriate cooling and heating operation. It becomes possible to do.

  In particular, in the operation control method for a multi-room air conditioner according to the first invention, the second invention is a cooling or heating operation, and when the operation frequency of the compressor is equal to or higher than a set frequency, the discharge pressure of the compressor Is less than the third set value, the opening of the second expansion valve is the first set opening, and when the discharge pressure is less than the fourth set value, the opening of the second expansion valve is By setting the second set opening, it is possible to prevent an excessive increase in the compressor low discharge temperature and at the same time to perform an appropriate cooling / heating operation.

  According to a third aspect of the present invention, in particular, in the operation control method for a multi-room air conditioner according to the first or second aspect, when the operation frequency of the compressor is equal to or higher than a set frequency during cooling or heating operation, the compressor When the discharge superheat degree calculated from the discharge temperature of the refrigerant, the outdoor heat exchanger temperature during cooling, and the indoor heat exchanger temperature during heating exceeds the fifth set value, the opening degree of the second expansion valve is increased. When the first set opening is set, and the discharge superheat degree exceeds the sixth set value, the opening of the second expansion valve is set to the second set opening, and the compressor low pressure decreases, and An appropriate cooling / heating operation can be performed while preventing an excessive increase in the compressor discharge temperature.

  The fourth aspect of the invention relates to the operation control method for a multi-room air conditioner according to any one of the first to third aspects of the invention, in particular, in the cooling or heating operation, the operation frequency of the compressor is equal to or higher than a set frequency, When the discharge temperature of the compressor is equal to or higher than a set value, the suction superheat degree calculated from the intake temperature of the compressor, the indoor heat exchanger temperature during cooling, and the outdoor heat exchanger temperature during heating is When the set value of 7 is exceeded, the opening of the second expansion valve is set to the first set opening, and when the degree of suction superheat exceeds the set value of 8, the opening of the second expansion valve is set to the first set opening. The set opening degree is set to 2, so that an excessive increase in the compressor discharge temperature can be prevented, and at the same time, an appropriate cooling / heating operation can be performed.

In particular, the fifth aspect of the present invention is the operation control method for a multi-room air conditioner according to any one of the first to fourth aspects, wherein the operation frequency of the compressor is equal to or higher than a set frequency during cooling operation, and the compressor When the difference between the outdoor heat exchanger temperature and the outdoor heat exchanger outlet temperature falls below the ninth set value when the discharge temperature of the refrigerant is equal to or higher than the set temperature and the outside air temperature is equal to or lower than the set temperature, the second expansion valve When the difference between the outdoor heat exchanger temperature and the outdoor heat exchanger outlet temperature is less than the tenth set value, the opening of the second expansion valve is set to the first set opening. The set opening degree is set to 2, which prevents an excessive increase in the compressor discharge temperature and at the same time allows proper cooling operation.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited by this embodiment.

(Embodiment 1)
FIG. 1 is a refrigeration cycle diagram showing an operation control method for a multi-room air conditioner according to the first embodiment of the present invention, and FIG. 2 is a flowchart showing an operation control method for the multi-room air conditioner. 3 is a time chart showing the operation control method of the multi-room air conditioner, and FIG. 4 is a block diagram showing the operation control method of the multi-room air conditioner. In addition, about the same part as the refrigerating cycle which shows the operation control method of the said conventional multi-chamber type air conditioner, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  In this embodiment, the second expansion valve 7a is used instead of the electromagnetic two-way valve 7 of the conventional liquid bypass circuit 3, and the other configuration is the same as the conventional one. The same reference numerals are given, and detailed descriptions of each are omitted.

  Next, the control operation of the second expansion valve 7a in the liquid bypass circuit 3 in the operation control method for the multi-chamber air conditioner in the present embodiment will be described with reference to FIGS.

  During the cooling or heating operation, the operation frequency of the compressor 1 is operating below the set frequency. At this time, the second expansion valve 7a in the liquid bypass circuit 3 is fully closed. Next, when the operating frequency of the compressor 1 is increased and the discharge temperature of the compressor 1 exceeds the first set value Td1 at a set value Hz1 or more, the opening degree of the second expansion valve 7a is set to the first value. Open to set opening PS1. Further, when the discharge temperature exceeds a second set value Td2 that is higher than the first set value Td1, the opening of the second expansion valve 7a is set to a second set opening that is larger than the first set opening PS1. Open up to PS2.

  As described above, according to the present embodiment, a so-called liquid sealing phenomenon in which refrigerant accumulates in the outdoor heat exchanger 4 occurs, and the refrigerant does not circulate, so that the discharge temperature of the compressor 1 becomes abnormally high. By opening the opening of the second expansion valve 7a and allowing the liquid refrigerant to flow to the accumulator 14, the discharge temperature can be prevented from rising, and an appropriate air conditioning operation can be performed.

(Embodiment 2)
FIG. 5 is a flowchart showing an operation control method for the multi-room air conditioner according to the second embodiment of the present invention, FIG. 6 is a time chart showing the operation control method for the multi-room air conditioner, and FIG. These are block diagrams which show the operation control method of the multi-room air conditioner. This embodiment is different from the first embodiment only in the operation control method, and the configuration of the multi-room air conditioner is the same as that of the first embodiment. The same reference numerals are given and the description thereof is omitted.

  5-7, the operation | movement of control of the 2nd expansion valve 7a in the liquid bypass circuit 3 in the operation control method of the multi-chamber air conditioner in this Embodiment is demonstrated.

  During the cooling or heating operation, the operation frequency of the compressor 1 is operating below the set frequency. At this time, the second expansion valve 7a in the liquid bypass circuit 3 is in a fully closed state. Next, when the operating frequency of the compressor 1 is equal to or higher than the set value Hz1 and the discharge pressure is lower than the third set value HP1, the opening of the second expansion valve 7a is reduced to the first set opening PS1. open. Further, when the discharge pressure falls below a fourth set value HP2, which is lower than the third set value HP1, the opening of the second expansion valve 7a is set to a second set opening wider than the first set opening PS1. Open to degree PS2.

  As described above, according to the present embodiment, when the discharge pressure is low even though the operating frequency of the compressor 1 is high, it is determined that the liquid seal in which the liquid refrigerant is accumulated in the outdoor heat exchanger 4 is generated. By flowing the liquid refrigerant to the accumulator 14, the high pressure can be increased and an appropriate air conditioning operation can be performed.

(Embodiment 3)
FIG. 8 is a flowchart showing an operation control method for a multi-room air conditioner according to the third embodiment of the present invention, FIG. 9 is a time chart showing the operation control method for the multi-room air conditioner, and FIG. These are block diagrams which show the operation control method of the multi-room air conditioner. This embodiment is different from the first embodiment only in the operation control method, and the configuration of the multi-room air conditioner is the same as that of the first embodiment. The same reference numerals are given and the description thereof is omitted.

  8-10, the operation | movement of control of the 2nd expansion valve 7a in the liquid bypass circuit 3 in the operation control method of the multi-chamber air conditioner in this Embodiment is demonstrated.

  During the cooling or heating operation, the operation frequency of the compressor 1 is operating below the set frequency. At this time, the second expansion valve 7a in the liquid bypass circuit 3 is fully closed.

  Next, when the operation frequency of the compressor 1 is equal to or higher than the set value Hz1, and during the cooling operation, the discharge superheat calculated from the discharge temperature of the compressor 1 and the outdoor heat exchanger temperature, or during the heating operation, When the discharge superheat degree calculated from the discharge temperature of the compressor 1 and the indoor heat exchanger temperature exceeds the fifth set value SHd1, the opening of the second expansion valve 7a is set to the first set opening PS1. Open until. Further, when the discharge superheat degree exceeds a sixth set value SHd2 larger than the fifth set value SHd1, the opening degree of the second expansion valve 7a is set to a second set opening degree larger than the first set opening degree PS1. Open to degree PS2.

  As described above, according to the present embodiment, since the refrigerant is not circulated due to liquid sealing or refrigerant gas loss, the second expansion valve 7a is opened to prevent the refrigerant discharge superheat from becoming abnormally high. By causing the refrigerant to flow to the accumulator 14, an increase in the discharge temperature can be prevented and an appropriate cooling operation can be performed.

(Embodiment 4)
FIG. 11 is a flowchart showing an operation control method for a multi-room air conditioner according to the fourth embodiment of the present invention, FIG. 12 is a time chart showing the operation control method for the multi-room air conditioner, and FIG. These are block diagrams which show the operation control method of the multi-room air conditioner. This embodiment is different from the first embodiment only in the operation control method, and the configuration of the multi-room air conditioner is the same as that of the first embodiment. The same reference numerals are given and the description thereof is omitted.

  11-13, the control operation of the second expansion valve 7a in the liquid bypass circuit 3 in the operation control method for the multi-chamber air conditioner in the present embodiment will be described.

  During the cooling or heating operation, the operation frequency of the compressor 1 is operating below the set frequency. At this time, the second expansion valve 7a in the liquid bypass circuit 3 is fully closed.

Next, when the operation frequency of the compressor 1 is equal to or higher than the set value Hz1 and the discharge temperature of the compressor 1 is equal to or higher than Td1, the cooling operation is calculated from the intake temperature of the compressor 1 and the indoor heat exchanger temperature. When the intake superheat degree is higher or when the intake superheat degree calculated from the intake temperature of the compressor 1 and the outdoor heat exchanger temperature exceeds the seventh set value SHs1 during the heating operation, the second expansion valve The opening of 7a is opened to the first set opening PS1. Furthermore, when the discharge superheat degree exceeds an eighth set value SHs2 larger than the seventh set value SHs1, the opening degree of the second expansion valve 7a is set to a second value larger than the first set opening degree PS1. Open to set opening PS2.

  As described above, according to the present embodiment, when the suction superheat degree increases, it is determined that the refrigerant is insufficient, and the second expansion valve 7a is opened to prevent the suction superheat degree from becoming abnormally high. Cooling operation can be performed.

(Embodiment 5)
FIG. 14 is a flowchart showing an operation control method for a multi-room air conditioner according to the fifth embodiment of the present invention, FIG. 15 is a time chart showing the operation control method for the multi-room air conditioner, and FIG. These are block diagrams which show the operation control method of the multi-room air conditioner. This embodiment is different from the first embodiment only in the operation control method, and the configuration of the multi-room air conditioner is the same as that of the first embodiment. The same reference numerals are given and the description thereof is omitted.

  14-16, the operation | movement of control of the 2nd expansion valve 7a in the liquid bypass circuit 3 in the operation control method of the multi-chamber air conditioner in this Embodiment is demonstrated.

  During the cooling operation, the operation frequency of the compressor 1 is operating below the set frequency. At this time, the second expansion valve 7a in the liquid bypass circuit 3 is fully closed.

  Next, when the operating frequency of the compressor 1 is equal to or higher than the set value Hz1 and the outside air temperature is lower than Ta1, the temperature difference calculated from the outdoor heat exchanger temperature and the outdoor heat exchanger outlet temperature is the ninth setting. When the value falls below the value Tco1, the opening of the second expansion valve 7a is opened to the first set opening PS1. Further, when the temperature difference falls below a tenth set value Tco2, which is smaller than a ninth set value Tco1, the opening of the second expansion valve 7a is set to a second set opening larger than the first set opening PS1. Open to degree PS2.

  As described above, according to the present embodiment, the fact that the temperature difference decreases means that the liquid refrigerant is accumulated in the outdoor heat exchanger 4 at the low outside air temperature, and the liquid refrigerant is sent to the accumulator 14. By flowing, proper cooling operation can be performed.

  As described above, the operation control method for a multi-room air conditioner according to the present invention can ensure a low pressure of the compressor without lowering the cooling or heating capacity. It can perform air conditioning operation and can be applied to various air conditioners.

Refrigeration cycle diagram showing an operation control method for a multi-room air conditioner according to Embodiment 1 of the present invention. Flowchart showing the operation control method of the multi-room air conditioner Time chart showing the operation control method of the multi-room air conditioner Block diagram showing the operation control method of the multi-room air conditioner The flowchart which shows the operation control method of the multi-room air conditioner in Embodiment 2 of this invention. Time chart showing the operation control method of the multi-room air conditioner Block diagram showing the operation control method of the multi-room air conditioner The flowchart which shows the operation control method of the multi-room air conditioner in Embodiment 3 of this invention. Time chart showing the operation control method of the multi-room air conditioner Block diagram showing the operation control method of the multi-room air conditioner The flowchart which shows the operation control method of the multi-room air conditioner in Embodiment 4 of this invention. Time chart showing the operation control method of the multi-room air conditioner Block diagram showing the operation control method of the multi-room air conditioner The flowchart which shows the operation control method of the multi-room air conditioner in Embodiment 5 of this invention. Time chart showing the operation control method of the multi-room air conditioner Block diagram showing the operation control method of the multi-room air conditioner Refrigeration cycle diagram showing the operation control method of a conventional multi-room air conditioner Flowchart showing the operation control method of the multi-room air conditioner Time chart showing the operation control method of the multi-room air conditioner Control block diagram showing the operation control method of the multi-room air conditioner

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 2 4-way valve 3 Liquid bypass circuit 4 Outdoor heat exchanger 5 Outdoor blower 7a Second expansion valve 8 Expansion valve (pressure reduction device)
DESCRIPTION OF SYMBOLS 9 Indoor heat exchanger 10 Indoor fan 11 Indoor piping temperature sensor 12 Indoor suction temperature sensor 14 Accumulator 21 Outdoor unit 22 Indoor unit

Claims (5)

A compressor, an accumulator, an outdoor fan, an outdoor heat exchanger, an outdoor unit provided with a pressure reducing device, and a plurality of indoor units connected to the outdoor unit, including an indoor heat exchanger and an indoor fan. A liquid bypass circuit that bypasses the outlet of the outdoor heat exchanger and the accumulator via a second expansion valve, and the operation frequency of the compressor is equal to or higher than a set frequency in cooling or heating operation When the discharge temperature of the compressor exceeds the first set value, the opening of the second expansion valve is set to the first set opening, and when the discharge temperature exceeds the second set value, the first An operation control method for a multi-chamber air conditioner, wherein the opening of the second expansion valve is the second set opening. During cooling or heating operation, when the compressor operating frequency is equal to or higher than the set frequency, the opening of the second expansion valve is set to the first set opening when the discharge pressure of the compressor falls below the third set value. The multi-chamber air conditioner according to claim 1, wherein when the discharge pressure falls below a fourth set value, the opening of the second expansion valve is set to the second set opening. Operation control method. It is calculated from the discharge temperature of the compressor, the outdoor heat exchanger temperature during cooling, and the indoor heat exchanger temperature during heating when the operating frequency of the compressor is equal to or higher than the set frequency during cooling or heating operation. When the discharge superheat degree exceeds the fifth set value, the opening degree of the second expansion valve is set to the first set opening degree, and when the discharge superheat degree exceeds the sixth set value, the second expansion valve The operation control method for a multi-chamber air conditioner according to claim 1 or 2, wherein the opening is set to a second set opening. During cooling or heating operation, when the operation frequency of the compressor is equal to or higher than a set frequency, and when the discharge temperature of the compressor is equal to or higher than a set value, the intake temperature of the compressor, and during cooling, the temperature of the indoor heat exchanger, If the intake superheat calculated from the outdoor heat exchanger temperature exceeds the seventh set value during heating, the opening of the second expansion valve is set to the first set open, and the intake superheat is The multi-chamber air conditioner according to any one of claims 1 to 3, wherein when the set value exceeds 8, the opening of the second expansion valve is set to a second set opening. Operation control method. During cooling operation, when the compressor operating frequency is higher than the set frequency, the compressor discharge temperature is higher than the set temperature, and the outside air temperature is lower than the set temperature, the outdoor heat exchanger temperature and the outdoor heat exchanger outlet temperature Is less than the ninth set value, the opening of the second expansion valve is set to the first set opening, and the difference between the outdoor heat exchanger temperature and the outdoor heat exchanger outlet temperature is the first set opening. The multi-chamber air conditioner according to any one of claims 1 to 4, wherein an opening of the second expansion valve is set to a second set opening when the set value is less than 10. Operation control method.