JP2001065949A - Controller for multi-chamber type air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To permit the prevention of superheating operation of a refrigerating cycle by a method wherein a means for operating the superheating degree of respective indoor heat exchangers by a pipeline temperature for respective heat exchangers is provided. SOLUTION: A superheating degree operating means 27 operates a superheating degree and a superheating degree of discharging operating means 28 operates the superheating degree of discharging respectively. A valve opening degree control mode table 33 sets the control contents (a value of valve travel and the like) of a variable pressure reducing device, which are capable of obtaining the optimum superheating degree and the optimum superheating degree of discharging in accordance with the operating frequency of a compressor. A valve travel control mode deciding means 31 decides the value of valve travel capable of obtaining the optimum superheating degree or the optimum superheating degree of discharging from the valve travel control mode table 33 in accordance with the operating frequency detected by a compressor operating frequency detecting means 32. In this case, respective values of the valve travel control table 33 are set by the values of experiments. According to this method, condensation on an indoor fan can be prevented while maintaining a high efficiency of a refrigerating cycle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration cycle of a multi-room air conditioner having one outdoor unit and a plurality of indoor units connected in parallel to the outdoor unit, and uses a variable decompression device. The present invention relates to a control device for a multi-room air conditioner that performs control for optimally controlling the degree of superheat of a refrigeration cycle and the degree of discharge superheat during a cooling operation or a heating operation.

[0002]

2. Description of the Related Art Generally, a multi-room air conditioner is configured as shown in FIG. Hereinafter, the configuration will be described. The outdoor unit C comprises a compressor 1, a four-way valve 2 for switching the flow of refrigerant, an outdoor heat exchanger 3, and variable pressure reducing devices 4A and 4B such as a pulse electric expansion valve. The indoor units A and B include indoor heat exchangers 5A and 5B, and connect the liquid side and the gas side of the outdoor unit C and the indoor units A and B to connection pipes 6A and 6A, respectively.
B and connected by connecting pipes 7A and 7B to form a closed circuit,
A heat pump cycle is configured by charging a refrigerant inside the closed circuit. Further, the outdoor unit C is provided with an outdoor fan 8, an outdoor suction temperature sensor 9, a compressor discharge temperature sensor 10, and a compressor suction temperature sensor 11. The indoor units A and B are provided with indoor fans 12A and 12B, indoor suction temperature sensors 13A and 13B, and indoor heat exchanger outlet temperature sensors 14A and 14B. Also,
The compressor 1 employs an inverter-driven frequency (capacity) variable control type, and its operating frequency is controlled by detecting the load state of each room (control means is not shown). In the above configuration, in the cooling operation state, the outdoor heat exchanger 3 functions as a condenser, the indoor heat exchangers 5A and 5B function as evaporators, and the refrigerant is a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, and a variable type. Decompression devices 4A, 4B, each indoor heat exchanger 5A,
5B, and circulates again from the four-way valve 2 to the compressor 1 to cool each room. At this time, the difference between the room temperature set temperature of the temperature controllers (not shown) of the indoor units A and B installed in each room and the actual room temperature detected by the indoor suction temperature sensors 13A and 13B is used. 1 is controlled. In addition, each indoor heat exchanger outlet temperature sensor 14
A, 14B detects the pipe temperature of the evaporator and controls the degree of opening of the variable decompression devices 4A, 4B so as to reach the set temperature.
In addition, discharge superheat degree control that indirectly suppresses an excessive rise in the discharge gas temperature of the compressor 1 has also been performed. Next, in the heating operation state, by switching the four-way valve 2, the flow of the refrigerant is reversed from that in the cooling operation, and the indoor heat exchangers 5A, 5B
, The outdoor heat exchanger 3 functions as an evaporator, and the refrigerant flows into the compressor 1, the four-way valve 2, the indoor heat exchanger 5
A, 5B, variable decompression devices 4A, 4B, outdoor heat exchanger 3
And circulate again from the four-way valve 2 to the compressor 1 to heat each room. At this time, the operating frequency of the compressor 1 is determined by the difference between the room temperature set temperature of the temperature controllers of the indoor units A and B installed in each room and the actual room temperature detected by the indoor suction temperature sensors 13A and 13B. Controlled. Also, the compressor suction temperature sensor 11 detects the suction temperature of the refrigerant gas, and controls the degree of valve opening of the variable decompression devices 4A and 4B so as to reach the set suction temperature. In addition, discharge superheat degree control for indirectly suppressing an excessive rise in the discharge gas temperature of the compressor 1 has also been performed.

[0003] These controls are realized by a microcomputer or the like as control means (the means themselves are not shown).

[0004]

However, in such a conventional control device for a multi-room air conditioner, during the cooling operation, the difference between the indoor set temperature of each room and the actual indoor temperature is not controlled. Regardless of the operating frequency of the compressor 1, the degree of superheat is controlled by adjusting the valve opening of the variable decompression devices 4A and 4B so that the preset indoor heat exchanger outlet temperature is maintained. The degree of superheat referred to here is the indoor heat exchanger 5
A, 5B, that is, the temperature difference between the evaporation saturation temperature of the evaporator and the outlet temperature of the indoor heat exchanger, and is usually set to a temperature difference of 5 to 10 degrees, that is, the degree of superheat. Therefore, this superheat degree control can provide a satisfactory control result to some extent. However, in the multi-room air conditioner, the indoor fans 12A, 12A, 1
There was a problem such as condensation on 2B. To elaborate,
In particular, due to the emergence of three-story houses and the demand for air conditioning throughout the building in recent years,
The installation form of the multi-room air conditioner is diversified, and there is a tendency for long piping, and the installation state of the indoor units A and B and the outdoor unit C is such that the pipe length is required to be 30 m or more. For example, indoor unit A
Is 2 m and the indoor unit B has a pipe length of 15 m, there is a large difference in the indoor unit pipe length.
On the side, the pressure loss due to the pipe length becomes 7 times or more, and even if the indoor unit A has the optimal superheat degree, the indoor unit B cannot be controlled to the optimal superheat degree and the superheat degree becomes too large. If the degree of superheat is too large, the air that has been cooled by heat exchange and the air that has been superheated without partially exchanging heat will mix and pass through the indoor fan 12B.
Dew condensation occurs on the blades of the indoor fan 12B, and in some cases, problems such as blowing out indoors to wet the tatami mats occur. Also,
By ensuring the optimum degree of superheat and discharge superheat in any load condition, high efficiency operation in which the cooling capacity and heating capacity per electric input of the air conditioner are increased, Since the operating frequency of the compressor 1 greatly changes depending on the load state of each room and the number of operating units, the superheat degree and the discharge superheat degree are not always controlled to the optimum state over the entire operation frequency range. Further, even during the heating operation, the operating frequency of the compressor 1 is controlled with respect to the difference between the outdoor temperature, the indoor set temperature of each room, and the actual indoor temperature. For the purpose of detecting the temperature and preventing the liquid refrigerant from returning to the compressor 1 to prevent the liquid compression operation and the high-efficiency operation, the valve openings of the variable pressure reducing devices 4A and 4B are set so that the set suction temperature is reached. , The discharge superheat degree control of the refrigeration cycle is performed. However, under the installation conditions such as a large difference in the pipe length as in the cooling operation, the optimum discharge superheat degree control cannot be obtained, and as a result, the compressor 1 There is a problem that liquid compression occurs due to the return of the refrigerant liquid to the compressor, and that the compressor is damaged and high-efficiency operation is hindered. Further, since the operating frequency of the compressor 1 greatly changes depending on the load state of each room and the number of operating units, the high efficiency operation of the refrigeration cycle and the discharge overheating without returning the refrigerant liquid to the compressor 1 over the entire operating frequency range. It was difficult to achieve degree control. Therefore, the present invention solves such a conventional problem and enables control of the superheat degree and discharge superheat degree of the refrigeration cycle over the entire operating frequency range of the compressor 1, and optimizes the superheat degree and discharge superheat degree of the heat exchanger. Condition to prevent dew condensation on the indoor fan during cooling operation, prevent liquid compression operation in the compressor, and excessively increase the discharge gas temperature of the compressor while maintaining high efficiency operation of the refrigeration cycle. The present invention provides a control device for a multi-room air conditioner capable of preventing overheating operation of a refrigeration cycle.

[0005]

In order to solve the above-mentioned problems, the invention according to claim 1 of the present invention provides an outdoor unit having a variable frequency control type compressor and an outdoor heat exchanger, and an indoor unit. A plurality of indoor units equipped with heat exchangers, and a variable decompression device corresponding to each indoor unit are provided in the middle of the refrigerant path piping of the outdoor heat exchanger and each indoor heat exchanger, and connected by connection piping. In the refrigeration cycle, the variable pressure reducing device is a variable pressure reducing device in which the valve opening is controlled by a control signal, and further provided in the middle of the refrigerant path piping of each of the indoor heat exchangers. An indoor heat exchanger intermediate temperature detecting means for detecting a temperature, and an indoor heat exchanger outlet temperature detecting means provided at an outlet of a refrigerant path pipe of each of the indoor heat exchangers and detecting a temperature of the refrigerant path pipe, These indoor heat exchanger intermediate temperature detection means And a superheat degree calculating means for calculating the degree of superheat of each indoor heat exchanger based on the respective pipe temperatures detected by the indoor heat exchanger outlet temperature detecting means, and a compressor operating frequency for detecting an operating frequency of the compressor. Detecting means, a valve opening control mode table in which a valve opening value of the variable pressure reducing device is set from a numerical value of the compressor operating frequency and a calculated value of the superheat calculating means, Means for determining the control mode of the variable pressure reducing device based on the value of the compressor operating frequency detected by the means and the value calculated by the superheat degree calculating means. A valve opening value is determined from the valve opening control mode table on the basis of the control mode determined by the above, and the valve opening of the variable pressure reducing device is adjusted by the variable pressure reducing device valve opening changing means. To, at the time of cooling operation, the control apparatus for a multi-room air conditioning apparatus is characterized in that to perform the superheat degree control of the refrigeration cycle.

According to a second aspect of the present invention, there is provided an outdoor unit having a variable frequency control type compressor and an outdoor heat exchanger,
A plurality of indoor units provided with an indoor heat exchanger, and a variable decompression device corresponding to each of the indoor units, provided in the middle of the refrigerant path piping of the outdoor heat exchanger and each indoor heat exchanger, with connection piping In the connected refrigeration cycle, the variable decompression device,
A variable pressure reducing device in which the valve opening is controlled by a control signal, and further provided in the middle of the refrigerant path pipe of the outdoor heat exchanger, and an outdoor heat exchanger intermediate temperature detecting means for detecting the temperature of the refrigerant path pipe; A compressor discharge temperature detecting means provided on the discharge pipe side of the compressor and detecting a pipe temperature at the provided position; and an outdoor heat exchanger intermediate temperature detecting means and a compressor discharge temperature detecting means. With each pipe temperature, discharge superheat degree calculating means for calculating the discharge superheat degree of the refrigeration cycle, compressor operating frequency detecting means for detecting the operating frequency of the compressor, and a numerical value of the compressor operating frequency, A valve opening control mode table in which a valve opening of the variable pressure reducing device is set from a calculation value of the discharge superheat calculating means, and a compression detected by the compressor operating frequency detecting means. Valve opening control mode determining means for determining a control mode of the variable pressure reducing device based on a numerical value of an operating frequency and a calculation value of the discharge superheat calculating means; and a control determined by the valve opening control mode determining means. Based on the mode, the valve opening value is determined from the valve opening control mode table, and the variable pressure reducing device valve opening changing means adjusts the valve opening of the variable pressure reducing device during cooling operation. A control device for a multi-room air conditioner, wherein discharge superheat degree control of a refrigeration cycle is performed.
The invention according to claim 3 provides a single outdoor unit having a frequency variable control compressor and an outdoor heat exchanger, a plurality of indoor units having an indoor heat exchanger, and each of the indoor units. A corresponding variable pressure reducing device is provided in the middle of the refrigerant path pipe between the outdoor heat exchanger and each indoor heat exchanger, and in a refrigeration cycle connected by a connection pipe, the variable pressure reducing device is controlled by a control signal to open the valve. A variable decompression device, which is controlled, and which is provided in the middle of the refrigerant path piping of each of the indoor heat exchangers, and detects an intermediate temperature of the indoor heat exchanger for detecting the temperature of the refrigerant path piping; An indoor heat exchanger outlet temperature detecting means provided at an outlet of a refrigerant path pipe of the exchanger and detecting a temperature of the refrigerant path pipe; and a refrigerant path pipe provided in the middle of the refrigerant path pipe of the outdoor heat exchanger. Outdoor heat exchanger that detects the temperature of And a compressor discharge temperature detecting means which is provided on the discharge pipe side of the compressor and detects a pipe temperature at the provided location. The indoor heat exchanger intermediate temperature detecting means and the indoor heat exchange means are provided. By each pipe temperature detected by the unit outlet temperature detecting means, the superheat degree calculating means for calculating the degree of superheat of each indoor heat exchanger, the outdoor heat exchanger intermediate temperature detecting means and the compressor discharge temperature detecting means, A discharge superheat degree calculating means for calculating a discharge superheat degree of the refrigeration cycle, a compressor operation frequency detection means for detecting an operation frequency of the compressor, and a numerical value of the compressor operation frequency based on each detected pipe temperature. A valve opening control mode table in which a valve opening value of the variable pressure reducing device is set based on the calculated values of the superheat degree calculating means and the discharge superheat degree calculating means; Valve opening degree control mode determining means for determining the control mode of the variable pressure reducing device based on the value of the compressor operating frequency detected by the frequency detecting means and the calculated value of the superheat degree calculating means and the discharge superheat degree calculating means, Based on the control mode determined by the valve opening control mode determining means, a valve opening value is determined from the valve opening control mode table, and the variable pressure reducing device valve opening changing means controls the variable pressure reducing device. A control device for a multi-room air conditioner, wherein a valve opening is adjusted to control a superheat degree and a discharge superheat degree of a refrigeration cycle during a cooling operation. The invention according to claim 4 is directed to a single outdoor unit having a frequency variable control compressor and an outdoor heat exchanger, a plurality of indoor units having an indoor heat exchanger, and each of the indoor units. A corresponding variable pressure reducing device is provided in the middle of the refrigerant path pipe between the outdoor heat exchanger and each indoor heat exchanger, and in a refrigeration cycle connected by a connection pipe, the variable pressure reducing device is controlled by a control signal to open the valve. An outdoor heat exchanger intermediate temperature detecting means for detecting the temperature of the refrigerant path pipe, which is provided in the middle of the refrigerant path pipe of the outdoor heat exchanger; The outdoor heat exchanger outlet temperature detecting means is provided at the outlet of the refrigerant path pipe for detecting the temperature of the refrigerant path pipe, and is detected by the outdoor heat exchanger intermediate temperature detecting means and the outdoor heat exchanger outlet temperature detecting means. Each distribution Superheat degree calculating means for calculating the degree of superheat of the outdoor heat exchanger based on temperature; compressor operating frequency detecting means for detecting the operating frequency of the compressor; numerical values of the compressor operating frequency and the superheat degree calculating means From the calculated value of, the valve opening control mode table in which the valve opening value of the variable pressure reducing device is set,
Valve opening control mode determining means for determining a control mode of the variable pressure reducing device based on a numerical value of the compressor operating frequency detected by the compressor operating frequency detecting means and a calculated value of the superheat degree calculating means; Based on the control mode determined by the opening control mode determining means, a valve opening value is determined from the valve opening control mode table, and the valve opening of the variable pressure reducing apparatus is changed by the variable pressure reducing apparatus valve opening changing means. A controller for a multi-room air conditioner, wherein the degree of superheat is controlled during a heating operation by controlling the degree of superheating of a refrigeration cycle.

According to a fifth aspect of the present invention, there is provided an outdoor unit having a variable frequency control type compressor and an outdoor heat exchanger,
A plurality of indoor units provided with an indoor heat exchanger, and a variable decompression device corresponding to each of the indoor units, provided in the middle of the refrigerant path piping of the outdoor heat exchanger and each indoor heat exchanger, with connection piping In the connected refrigeration cycle, the variable decompression device,
An indoor heat exchanger intermediate temperature detecting means which is provided in the middle of a refrigerant path pipe of each of the indoor heat exchangers and detects the temperature of the refrigerant path pipe, wherein the variable pressure reducing apparatus has a valve opening controlled by a control signal. And, provided on the discharge pipe side of the compressor, compressor discharge temperature detection means for detecting the pipe temperature of the provided location, by each of these indoor heat exchanger intermediate temperature detection means and compressor discharge temperature detection means, A discharge superheat degree calculating means for calculating a discharge superheat degree of the refrigeration cycle, a compressor operation frequency detection means for detecting an operation frequency of the compressor, and a numerical value of the compressor operation frequency based on each detected pipe temperature. A valve opening control mode table in which a valve opening of the variable decompression device is set based on a calculation value of the discharge superheat calculating means, and the compressor operating frequency detecting means detects the valve opening control mode table. Valve opening control mode determining means for determining a control mode of the variable pressure reducing device based on a numerical value of the compressor operating frequency and a calculation value of the discharge superheat calculating means, and a determination is made by the valve opening control mode determining means; Based on the control mode, the valve opening value is determined from the valve opening control mode table, and the valve opening of the variable pressure reducing device is adjusted by the variable pressure reducing device valve opening changing means so as to adjust the valve opening during the heating operation. The control device for a multi-room air conditioner according to any one of claims 1 to 3, wherein discharge superheat control of the refrigeration cycle is performed.

According to a sixth aspect of the present invention, there is provided an outdoor unit having a variable frequency control type compressor and an outdoor heat exchanger,
A plurality of indoor units provided with an indoor heat exchanger, and a variable decompression device corresponding to each of the indoor units, provided in the middle of the refrigerant path piping of the outdoor heat exchanger and each indoor heat exchanger, with connection piping In the connected refrigeration cycle, the variable decompression device,
A variable pressure reducing device in which the valve opening is controlled by a control signal, and further provided in the middle of the refrigerant path pipe of the outdoor heat exchanger, and an outdoor heat exchanger intermediate temperature detecting means for detecting the temperature of the refrigerant path pipe; An outdoor heat exchanger outlet temperature detecting means that is provided at an outlet of a refrigerant path pipe of the outdoor heat exchanger and detects a temperature of the refrigerant path pipe, and is provided in the middle of a refrigerant path pipe of each of the indoor heat exchangers. , Each indoor heat exchanger intermediate temperature detection means for detecting the temperature of the refrigerant path piping,
Provided on the discharge pipe side of the compressor, a compressor discharge temperature detecting means for detecting the pipe temperature of the provided location,
Superheat degree calculating means for calculating the degree of superheat of the outdoor heat exchanger based on the respective pipe temperatures detected by the outdoor heat exchanger intermediate temperature detecting means and the outdoor heat exchanger outlet temperature detecting means; Discharge superheat degree calculating means for calculating the discharge superheat degree of the refrigeration cycle based on the respective pipe temperatures detected by the compressor intermediate temperature detecting means and the compressor discharge temperature detecting means, and compression detecting the operating frequency of the compressor. Valve opening degree control in which a valve opening degree value of the variable pressure reducing device is set based on a machine operation frequency detection means, a value of the compressor operation frequency, and a calculation value of the superheat degree calculation means and the discharge superheat degree calculation means. A mode table, a numerical value of the compressor operating frequency detected by the compressor operating frequency detecting means, and a variable calculated by the superheat calculating means and the discharge superheat calculating means. A valve opening control mode determining means for determining a control mode of the pressure reducing device is provided, and a valve opening value is determined from the valve opening control mode table based on the control mode determined by the valve opening control mode determining means. The variable decompression device valve opening change means, by adjusting the valve opening of the variable decompression device, during the heating operation, superheat degree of the refrigeration cycle and discharge superheat degree is controlled. This is a control device for a multi-room air conditioner.

According to a seventh aspect of the present invention, there is provided a superheat degree priority judging means during a cooling operation and a discharge superheat degree priority judgment means during a heating operation. The degree-of-priority determining means gives priority to the superheat degree control over the discharge superheat degree control during the cooling operation, and the discharge superheat degree priority determining means gives priority to the discharge superheat degree control over the superheat degree control during the heating operation. A control device for a multi-room air conditioner, characterized in that:

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.

In FIG. 1, an outdoor unit C includes a compressor 1 of an inverter-driven variable frequency control type (variable capacity type), a four-way valve 2 for switching a refrigerant flow to switch between a cooling operation and a heating operation, and an outdoor heat exchanger. 3, and a variable pressure reducing device 4 comprising an electric expansion valve whose valve opening is controlled by, for example, a stepping motor whose rotation is controlled by a pulse signal.
A, 4B. Each of the indoor units A and B includes an indoor heat exchanger 5A and an indoor heat exchanger 5B. Then, the outdoor unit C and the indoor units A and B are connected by liquid-side connection pipes 6A and 6B and gas-side connection pipes 7A and 7B, respectively, to form a closed circuit. A cycle is formed, and a heat pump cycle capable of cooling and heating operation is configured. Further, the outdoor unit C is provided on the discharge side of the compressor 1 with an outdoor fan 8 as a blower provided opposite the outdoor heat exchanger 3, an outdoor suction temperature sensor 9 as a detector for the outside air temperature. , A compressor discharge temperature sensor 10 as a means for detecting the temperature of the pipe at the provided location, and an outdoor as a means for detecting the temperature of the refrigerant path pipe provided at the outlet of the refrigerant path pipe of the outdoor heat exchanger 3 A heat exchanger outlet temperature sensor 11 and an outdoor heat exchanger intermediate temperature sensor 12 that is provided in the middle of the refrigerant path pipe of the outdoor heat exchanger 3 and detects the temperature of the refrigerant path pipe are provided. . In the indoor units A and B, indoor fans 13A and 13B as blowing means provided opposite to the indoor heat exchangers 5A and 5B, indoor suction temperature sensors 14A and 14B as room temperature detecting means, and indoor heat exchange are provided. Provided at the outlet of the refrigerant path piping of the vessels 5A and 5B,
Indoor heat exchanger outlet temperature sensors 15A and 15B as means for detecting the temperature of the refrigerant path pipes, and further provided in the refrigerant path pipes of the indoor heat exchangers 5A and 5B to detect the temperature of the refrigerant path pipes For this purpose, the indoor heat exchanger intermediate temperature sensors 16A and 16B are provided as means for performing the operation.

In the above configuration, the operation of the indoor units A and B together is as follows.

During the cooling operation, the indoor fans 13A, 13A
B, the outdoor fan 8 and the compressor 1 are operated, and the refrigerant discharged from the compressor 1 flows through the four-way valve 2, the outdoor heat exchanger 3, the variable decompression devices 4A and 4B, and the indoor heat exchangers 5A and 5B. Then, each room is cooled by circulating in order from the four-way valve 2 to the compressor 1 again.

During the heating operation, the four-way valve 2 is switched, and the indoor fans 13A, 13B and the outdoor fan 8 and the compressor 1 are operated as in the cooling operation. Refrigerant discharged from the
Four-way valve 2, indoor heat exchangers 5A, 5B, variable pressure reducing device 4
A, 4B, flow to the outdoor heat exchanger 3, and circulate again from the four-way valve 2 to the compressor 1 to heat each room.

The compressor 1 is driven by an inverter.
The variable operation frequency range is 15 Hz to 100 during cooling operation.
Hz, 15Hz ~ 130Hz during heating operation, variable width is wide,
The initial setting of the operation frequency and the valve opening of the variable pressure reducing devices 4A and 4B is determined as a total load level based on the number of operating indoor units A and B and the load state of each room.

Next, the operation frequency of the compressor 1 and a method of determining the initial setting of the valve opening of the variable pressure reducing devices 4A and 4B will be described with reference to Table 1 below. Here, for convenience of explanation, the table is simplified and described.

[0017]

[Table 1]

When one of the indoor units A and B is operated, the temperature difference Δ
T is assumed to be small and L1 to L3.

In Table 1, the temperature difference ΔT is calculated for each of the indoor units A and B.
Is the difference (Tr-Ts) between the set temperature Ts of the temperature controller (not shown) and the actual room temperature Tr detected by the indoor suction temperature sensors 14A and 14B. That is, this temperature difference Δ
The magnitude of T (= Tr−Ts) is regarded as the magnitude of the load on each of the indoor units A and B.

The operating frequency of the compressor 1 according to the total load (the load of the indoor unit A plus the load of the indoor unit B) is determined by the large, medium, and small differential temperatures ΔT of the indoor units A and B, and the operating frequency is matched. The initial setting levels of the valve openings of the variable pressure reducing devices 4A and 4B are set as L1 to L5.

For example, if the load on both the indoor units A and B is large, the level is set to L5, the compressor 1 is operated at a high frequency, and the initial set value of the valve opening of the variable pressure reducing device is also large. Becomes

Conversely, if the load in each chamber is small, L
1, the compressor 1 is operated at a low frequency, and the valve openings of the variable pressure reducing devices 4A, 4B are set to small valve openings.

When one of the indoor units A or B is operated, the load of one of the stopped indoor units is regarded as small. When the load of the indoor unit A is large (ΔT = large), the variable pressure reducing device 4A is operated with the valve opening set to the level of L3.

Next, the configuration and operation of the control device according to the embodiment of the present invention will be described with reference to the control block diagram of FIG.

In FIG. 2, an operation mode input means 26 selects a cooling operation or a heating operation according to the operation of a cooling / heating operation switch (not shown).

Reference numeral 20 denotes an indoor heat exchanger intermediate temperature detecting means, which is the indoor heat exchanger intermediate temperature sensors 16A and 16A shown in FIG.
6B. Further, reference numeral 21 denotes an indoor heat exchanger outlet temperature detecting means, which is an indoor heat exchanger outlet temperature sensor 15A,
5B.

Reference numeral 22 denotes an outdoor heat exchanger intermediate temperature detecting means.
This corresponds to the outdoor heat exchanger intermediate temperature sensor 12 in FIG. Reference numeral 23 denotes an outdoor heat exchanger outlet temperature detecting means, which corresponds to the outdoor heat exchanger outlet temperature sensor 11 in FIG.

Reference numeral 24 denotes compressor discharge temperature detecting means, which corresponds to the compressor discharge temperature sensor 10 in FIG.

Reference numeral 25 denotes an operation mode judging means for judging an operation mode of a cooling operation or a heating operation based on a signal of the operation mode input means 26.

Reference numeral 27 denotes superheat degree calculating means, and reference numeral 28 denotes discharge superheat degree calculating means.
The superheat degree calculation means 27 calculates the superheat degree by using the value obtained by the necessary temperature detection means from the detected temperatures of the respective temperature detection means 20 to 24 depending on the operation state according to the operation mode signal outputted by Further, the discharge superheat degree calculating means 28 calculates the discharge superheat degree.

Reference numeral 29 denotes a superheat degree priority judging means. When the signal of the superheat degree calculating means 27 is output during the cooling operation, the superheat degree calculating means 27 sends the signal to the valve opening degree control mode judging means 31 until the superheat degree control is completed. A signal is output so as not to receive the signal from the discharge superheat degree calculating means 28.

Numeral 30 is a discharge superheat priority determining means. When a signal from the discharge superheat calculating means 28 is output during the heating operation, the discharge superheat degree is determined by the valve opening control mode determining means 31.
Superheat degree calculating means 27 until the discharge superheat degree control is completed.
The signal is output so as not to accept the signal.

Reference numeral 33 denotes a valve opening control mode table, which controls the variable pressure reducing devices 4A and 4B that can obtain the optimum degree of superheat and discharge superheat in accordance with the value of the operating frequency of the compressor 1 (valve opening). Degrees). Here, for convenience of explanation, control is performed in three steps, steps A, B, and C, corresponding to the numerical value of the operating frequency of the compressor 1, and S1 to S4 described later.
3 control modes are set.

Reference numeral 32 denotes compressor operating frequency detecting means for detecting the operating frequency of the compressor 1.

Numeral 31 denotes a valve opening control mode judging means, which determines a valve opening value at which an optimum degree of superheat or discharge superheat is obtained in accordance with the operating frequency detected by the compressor operating frequency detecting means 32. The determination is made from the opening control mode table 33. Here, each value of the valve opening control mode table 33 is set by an experimental value.

Numeral 34 denotes a variable pressure reducing device valve opening changing means.
A signal is output according to the optimal valve opening control mode selected by the valve opening control mode determining means 31.

A variable pressure reducing device output means 35 outputs a pulse signal based on a signal from the variable pressure reducing device valve opening changing means 34 to the variable pressure reducing devices 4A and 4B. As a result, the variable decompression devices 4A and 4B adjust the valve opening so as to always obtain the optimum degree of superheat or discharge superheat.
Hereinafter, the control in each operation state will be described in detail. Here, for convenience of explanation, the control of the indoor unit A will be described from the state where two indoor units are simultaneously operated and the refrigeration cycle is stable.

First, the basic concept of superheat control and discharge superheat control will be described with reference to FIGS.

In FIG. 3, when the degree of superheat SH temporarily exceeds the value of threshold value a and exceeds the value of threshold value b, that is, the superheat degree SH continues for 10 minutes or more with respect to the change in the degree of superheat SH. Opens the valve opening of the variable pressure reducing device 4A by eight pulses from the initial setting value of the valve opening corresponding to the operating frequency of the compressor 1. By opening the valve opening by eight pulses, the degree of superheat SH is reduced experimentally by about 1 degree normally. The degree of superheat is controlled by repeatedly performing this operation.

In the region F, the operation of the variable pressure reducing device 4A is maintained at the initial value and the superheat control is performed so that the superheat SH does not always become excessive.

In FIG. 4, in response to a change in the discharge superheat degree tSH, the discharge superheat degree tSH is once lower than the threshold value c and lower than the threshold value d, that is, continues for 10 minutes or more in the region G. In this case, the valve opening of the variable pressure reducing device 4A is further closed by eight pulses from the initial value of the valve opening corresponding to the operating frequency of the compressor 1.

By closing the valve opening by 8 pulses, the discharge superheat degree tSH usually increases experimentally by about 1 degree. By repeating this operation, the degree of discharge superheat is controlled.

When it is in the region H, the operation of the variable pressure reducing device 4A is kept at the initial set value and the discharge superheat degree is controlled so that a constant discharge superheat degree tSH is always secured. You.

Next, the control block diagram of FIG. 2 and FIG.
The superheat degree control during the cooling operation will be described with reference to the flowchart of FIG. Here, it is assumed that the superheat priority determination means 29 is operating for convenience of explanation.

First, the indoor heat exchanger intermediate temperature detecting means 20
, The indoor heat exchanger intermediate temperature is detected by the indoor heat exchanger outlet temperature detecting means 21 and the indoor heat exchanger outlet temperature is detected by the indoor heat exchanger outlet temperature detecting means 21 (S101, S102).
And the superheat degree calculating means 27 calculates the superheat degree SH of the indoor heat exchanger 5A (S103).

Here, the degree of superheat is the difference between the detected indoor heat exchanger intermediate temperature Tc and the indoor heat exchanger outlet temperature Tu (Tu-Tc).
Is calculated by the superheat degree calculating means 27.

Subsequently, the compressor operating frequency is detected by the compressor operating frequency detecting means 32 (S104). Here, S1, S2, and S3 in FIG. 5 are subroutines, and indicate the control modes set in the valve opening control mode table 33.

If the operating frequency of the compressor is lower than 30 Hz by the valve opening control mode determining means 31, the process proceeds to step A, and the control mode S1 is selected. 30Hz or more and 5
If it is less than 0 Hz, the process proceeds to step B and selects the control mode S2. If neither is found, the process proceeds to step C to select the control mode S3.

In step A, if the superheat degree SH is equal to or higher than 5.0 degrees, as shown in FIG. 3, the superheat degree SH is determined to be in the E region (S111), and this state is continued for 10 minutes or more. In this case, the valve opening of the variable pressure reducing device 4A is opened by eight pulses, and the timer is cleared (S112 to S114).

When the superheat degree SH is less than 5.0 degrees, whether the superheat degree SH is 3.5 degrees or more (S1
15) It is determined that the area is not the area F (S116), and if it is less than 3.5 degrees, the area is determined to be the area F (S117). Then, the timer is cleared. At this time, since the timer is 10 minutes or less, the process returns to START (S100).

When the angle is equal to or more than 3.5 degrees and is already in the area E, E
The control in S111 to S114 is performed assuming that the area exists. Hereinafter, this control is repeated.

Similarly, when the process proceeds to step B, the control contents and steps are the same as those in step A (S
120 to S129), the value of the threshold value a in FIG. 3 is 4.5 degrees and the value of the threshold value b is 3.0 degrees.

Similarly, when the process proceeds to step C, the control contents and steps are the same as those in step A (S
130 to S139), the value of the threshold value a in FIG. 3 is 3.5 degrees, and the value of the threshold value b is 2.0 degrees.

Here, the set frequency of the compressor 1 is 30 to 5
Although the description has been given of adjusting the valve opening of the variable pressure reducing device 4A by detecting the center frequency at 0 Hz, this frequency is a practical operation frequency range at temperatures around the rainy season, and the possibility of condensation on the indoor fan 13 is the highest. Because of the high climate.

Regarding the degree of superheat, the range of 5.0 to 2.0 degrees corresponding to the operation frequency is set in the control mode S1,
The control was performed in three stages, S2 and S3, but this is merely an example, and the circulating refrigerant is completely evaporated at the outlet of the indoor heat exchanger 5A, and dew condensation is hardly generated on the surface of the indoor fan 13A. It is a value confirmed by experiments that high efficiency operation of the cycle can be obtained.

The monitoring time of the degree of superheat was set to 10 minutes, which is set because the condensation on the indoor fan 13A normally grows in approximately 10 minutes experimentally.
This time may be changed depending on conditions or the like.

The valve opening of the variable pressure reducing device 4A was set to 8 pulses per time, and it was confirmed by an experiment that a superheat degree change of about 1 degree was obtained with the valve opening of 8 pulses. Value.

The above numerical values are different depending on the components of the compressor 1, such as the capacity of the compressor 1 and the sizes of the variable pressure reducing devices 4A and 4B, and are set as experimental values.

By this control, it is possible to prevent condensation on the indoor fan 13A while maintaining the high efficiency operation of the refrigeration cycle in the entire operating frequency range of the compressor 1 during the cooling operation.

Next, control of the discharge superheat degree during the cooling operation will be described with reference to the control block diagram of FIG. 2 and the flowchart of FIG.

First, as shown in the flowchart of FIG. 6, the outdoor heat exchanger intermediate temperature detecting means 22 detects the outdoor heat exchanger intermediate temperature, and the compressor discharge temperature detecting means 24 detects the compressor discharge temperature. S201, S202),
The signal from the operation mode determination means 25 is input, and the discharge superheat degree calculation means 28 calculates the discharge superheat degree tSH (203). Here, the discharge superheat degree tSH is the difference between the detected compressor discharge temperature Td and the outdoor heat exchanger intermediate temperature Tm (Td−
Tm) is calculated by the discharge superheat calculating means 28.

Subsequently, the compressor operating frequency is detected by the compressor operating frequency detecting means 32 (S204). Here, S21, S22, and S23 in FIG. 6 are subroutines, and indicate the control modes set in the valve opening control mode table 33.

If the operating frequency of the compressor is less than 40 Hz by the valve opening control mode determining means 31, the process proceeds to step A and the control mode S21 is selected. 40Hz or more and 60
If it is less than Hz, the process proceeds to step B and the control mode S22 is selected. If not, the process proceeds to step C and selects the control mode S23.

When the process proceeds to step A, the discharge superheat degree tS
If H is 8 degrees or less, as shown in FIG.
SH is determined to be in the region G (S211), and if this state is continued for 10 minutes or more, the valve opening of the variable pressure reducing device 4A is set to 8
Close the pulse and clear the timer (S212 to S21)
4).

When the discharge superheat degree tSH exceeds 8 degrees, if the discharge superheat degree SH is 9 degrees or less (S21).
5) It is determined that it is not already in the area G (S216), and 9
If it exceeds the degree, it is determined that the area is H (S217). Then, the timer is cleared. At this time, since the timer is 10 minutes or less, the process returns to START (S200).

When the discharge superheat degree tSH is 9 degrees or less and the area is already in the area G, it is considered that the area is in the area G, and the control of S211 to S214 is performed. Hereinafter, this control is repeated.

Similarly, when the process proceeds to step B, the control contents and steps are the same as those in step A (S
220 to S229), the value of the threshold value c is 9 degrees and the value of the threshold value d is 10 degrees in FIG.

Similarly, when the process proceeds to step C, the control contents and steps are the same as those in step A (S
230 to S239), the value of the threshold value c is 10 degrees and the value of the threshold value d is 11 degrees in FIG.

Here, the set frequency of the compressor 1 is 40 to 6
Although the description has been given of adjusting the opening degree of the variable decompression devices 4A and 4B by detecting about 0 Hz, this frequency is a practical operation frequency range in a normal summer temperature.

Regarding the discharge superheat degree tSH, the range of 8 to 11 degrees is set in the control mode S corresponding to the operation frequency.
The control was performed in three stages, ie, 21, S22 and S23, but this is an example, and it is possible to prevent the liquid compression operation of the compressor 1 and to obtain a high efficiency operation of the refrigeration cycle in which the cooling capacity per electric input is increased. Is the value confirmed in the experiment.

Further, the monitoring time of the discharge superheat was set to 10 minutes, but this is merely an example. After the opening of the variable pressure reducing device 4A was changed, the discharge superheat clearly changed and the discharge superheat was changed. The length may be set so that the change does not affect the liquid compression prevention and the high-efficiency operation of the compressor 1.

The opening degree of the variable pressure reducing device 4A is set to 8 pulses per time.
It is a value confirmed by experiments that the degree of discharge superheat change can be obtained.

It is desirable that each of the above numerical values be set as an experimental value according to the conditions of the equipment to be used, as in the above-described superheat control.

According to this control, during the cooling operation, the discharge superheat degree tSH is controlled to an optimum state in the entire operating frequency range of the compressor 1 to maintain the high efficiency operation of the refrigeration cycle while the liquid compression of the compressor 1 is maintained. Driving can be prevented.

Next, superheat control during the heating operation will be described with reference to the control block diagram of FIG. 2 and the flowchart of FIG. Here, it is assumed that the discharge superheat priority determination means 30 is operating for convenience of explanation.

First, as shown in the flowchart of FIG. 7, the outdoor heat exchanger intermediate temperature is detected by the outdoor heat exchanger intermediate temperature detecting means 22, and the outdoor heat exchanger outlet temperature is detected by the outdoor heat exchanger outlet temperature detecting means 23. (S301, S301
302), a signal from the operation mode determination means 25 is input, and the superheat degree SH of the outdoor heat exchanger 3 is calculated by the superheat degree calculation means 27 (S303).

Subsequently, the compressor operating frequency is detected by the compressor operating frequency detecting means 32 (S304). Here, FIG.
S31, S32 and S33 are subroutines, and indicate the control modes set in the valve opening control mode table 33.

If the operating frequency of the compressor is lower than 40 Hz by the valve opening control mode determining means 31, the process proceeds to step A and selects the control mode S31. 40Hz or more and 8
If it is less than 0 Hz, the process proceeds to step B and the control mode S32
Select If neither is found, the process proceeds to step C to select the control mode S33.

When the process proceeds to step A, the superheat degree SH becomes 6
If it is not less than degree, as shown in FIG. 3, the superheat degree SH is determined to be in the E region (S311), and if this state is continued for more than 10 minutes, the valve opening degree of the variable pressure reducing devices 4A and 4B is set to 8 pulses. Open and clear the timer (S312 to S314).

When the superheat degree SH is less than 6 degrees, if the superheat degree SH is 5 degrees or more (S315), it is determined that the superheat degree SH is not already in the area E (S316). Is determined (S317). Then, clear the timer. At this time, the timer is less than 10 minutes, so
It returns to (S300).

If the degree of superheat SH is 5 degrees or more and the area is already in the area E, it is assumed that the area is in the area E, and the control of S311 to S314 is performed. Hereinafter, this control is repeated.

Similarly, when the process proceeds to step B, the control contents and steps are the same as those in step A (S
320 to S329), the value of the threshold value a in FIG. 3 is 7 degrees, and the value of the threshold value b is 6 degrees.

Similarly, when the process proceeds to step C, the control contents and steps are the same as those in step A (S
330 to S339), the value of the threshold value a in FIG. 3 is 8 degrees, and the value of the threshold value b is 7 degrees.

Here, the set frequency of the compressor is 40-80.
Although the description has been given of adjusting the opening degree of the variable pressure reducing device 4A by detecting the center frequency Hz, this frequency is a practical operation frequency range at the time of heating at normal winter temperature.

As for the degree of superheat SH, the range of 5 to 8 degrees is set in the control modes S31, S
The control was performed in three stages, S32 and S33, but this is an example, and the high efficiency operation of the refrigeration cycle in which the heating capacity per electric input is increased is maintained, and the discharge gas temperature of the compressor 1 is prevented from excessively increasing. This is a value confirmed by experiments that overheating operation can be prevented.

The monitoring time of the degree of superheat was set to 10 minutes. This is because the degree of superheat obviously changed after the opening of the variable pressure reducing device was changed, and the change in the degree of superheat was caused by the superheat operation of the refrigeration cycle. The length may be set so as not to affect prevention and high-efficiency operation.

The opening degree of the variable pressure reducing device 4A is set to 8 pulses per time.
It is a value confirmed by experiments that a degree of superheat change can be obtained.

Note that each of the above numerical values changes according to the conditions of the equipment to be used, as described above, and it is desirable to set them with experimental values.

According to this control, during the heating operation, the superheat degree is controlled to the optimum state in the entire operating frequency range of the compressor 1 to maintain the high efficiency operation of the refrigeration cycle, while the discharge gas temperature of the compressor is excessive. A remarkable rise can be prevented, and the overheating operation of the refrigeration cycle can be prevented.

Next, control of the discharge superheat degree during the heating operation will be described with reference to the control block diagram of FIG. 2 and the flowchart of FIG.

First, as shown in the flowchart of FIG. 8, the indoor heat exchanger intermediate temperature detecting means 20 detects the indoor heat exchanger intermediate temperature, and the compressor discharge temperature detecting means 24 detects the compressor discharge temperature. (S401, S40
2), a signal from the operation mode determination means 25 is input, and the discharge superheat degree calculating means 28 calculates the discharge superheat degree tSH (S403).

Here, the discharge superheat degree tSH is calculated by the discharge superheat degree calculation means 28 as a difference (Tdh-Tmh) between the detected compressor discharge temperature Tdh and the indoor heat exchanger intermediate temperature Tmh.

Subsequently, the compressor operating frequency is detected by the compressor operating frequency detecting means 32 (S404). Here, S41, S42, and S43 in FIG. 8 are subroutines, and indicate the control modes set in the valve opening control mode table 33.

If the operating frequency of the compressor 1 is less than 40 Hz by the valve opening control mode determining means 31, step A
And the control mode S41 is selected. If it is 40 Hz or more and less than 60 Hz, the process proceeds to step B and the control mode S4
Select 2. If neither is found, the process proceeds to step C to select the control mode S43.

When the process proceeds to step A, the discharge superheat degree tS
If H is 8 degrees or less, as shown in FIG.
SH is determined to be in the area G (S411), and if this state is continued for 10 minutes or more, the valve opening of the variable pressure reducing device 4A is set to 8
Close the pulse and clear the timer (S412 to S41
4).

When the discharge superheat degree tSH exceeds 8 degrees, if the discharge superheat degree tSH is 9 degrees or less (S4).
15) It is determined that the area is not already the area G (S416), and when it exceeds 9 degrees, it is determined that the area is the area H (S417).
Then, the timer is cleared. At this time, since the timer is 10 minutes or less, the process returns to START (S400).

When the discharge superheat degree tSH is 8 degrees or less and the area is already in the area G, it is considered that the area is in the area G, and the control of S411 to S414 is performed. Hereinafter, this control is repeated.

Similarly, when the process proceeds to step B, the control contents and steps are the same as those in step A (S
420 to S429), the value of the threshold value c is 9 degrees and the value of the threshold value d is 10 degrees in FIG.

Similarly, when the process proceeds to step C, the control contents and steps are the same as those in step A (S
430 to S439), the threshold value c in FIG. 4 is 10 degrees, and the threshold value d is 11 degrees.

The discharge superheat degree is set in the control mode S41 in the range of 8 to 11 degrees corresponding to the operation frequency.
S42 and S43 were controlled in three stages, but this is merely an example, and experiments have shown that it is possible to prevent liquid compression of the compressor 1 and to obtain a high efficiency operation of the refrigeration cycle in which the cooling capacity per electric input is increased. This is the confirmed value.

The monitoring time of the discharge superheat was set to 10 minutes, but this is merely an example. After the opening of the variable pressure reducing device 4A was changed, the discharge superheat clearly changed, and the discharge superheat was changed. The length may be set so that the change does not affect the liquid compression prevention and the high-efficiency operation of the compressor 1.

Further, the opening of the variable pressure reducing device 4A is set to 8 pulses per time.
It is a value confirmed by experiments that the degree of discharge superheat change can be obtained.

The above numerical values are the same as in the cooling operation.
It depends on the conditions of the equipment used, etc., and is preferably set with experimental values.

According to this control, during the heating operation, the discharge superheat degree is controlled to an optimum state in the entire operating frequency range of the compressor 1, and the liquid compression operation of the compressor 1 is performed while maintaining the high efficiency operation of the refrigeration cycle. Can be prevented.

Although the above description has been made with reference to the control of the indoor unit A, the control of the indoor unit B is also controlled in the same manner as described above.

That is, when the superheat control or the discharge superheat control of the indoor unit A is performed, the pressure (refrigerant circulation amount) in the refrigeration cycle fluctuates and slightly affects the indoor unit B. Thus, the indoor unit B is controlled in the same manner as the indoor unit A described above so that an appropriate degree of superheat or discharge superheat is obtained, and the operation is performed so as to obtain the balance of the refrigeration cycle as a whole.

The indoor heat exchanger intermediate temperature sensor 16
A, 16B and indoor heat exchanger outlet temperature sensors 15A, 15
B and the outdoor heat exchanger intermediate temperature sensor 12 and the outdoor heat exchanger outlet temperature sensor 11 provide the indoor unit A,
Even if there is a large difference between the pipe lengths of the connection pipes 6A, 6B, 7A, and 7B of B, the pipe temperature of each heat exchanger itself is detected regardless of the pipe length, and the net superheat degree SH and discharge superheat degree tSH are reduced. It will be calculated.

Further, by providing the superheat degree priority judging means 29 shown in FIG. 2 during the cooling operation, if any one of the rooms is under superheat degree control, the discharge superheat degree control is performed in a standby state. Can not be done until is over.

Further, during the heating operation, by providing the discharge superheat priority determination means 30 shown in FIG. 2, if the discharge superheat control is being performed in any one of the chambers, the superheat control is performed in the standby state while the discharge superheat is being controlled. It is not performed until the degree control ends.

The reason for performing this priority control is that, during cooling operation, prevention of dew condensation on the indoor fan 13A is more important in practical use than high efficiency operation of the refrigeration cycle and prevention of overheating operation. The prevention of the liquid compression operation, which secures a constant discharge superheat degree and prevents the liquid refrigerant from returning to the compressor 1, is more effective than the refrigeration cycle high efficiency operation and the overheating operation prevention.
This is because it is important in practical use.

By providing the superheat degree priority judging means 29 and the discharge superheat degree priority judging means 30, when the superheat degree control and the discharge superheat degree control are simultaneously adopted, the optimum superheat degree control and the optimal discharge superheat degree can be attained. Control that achieves both is possible.

Further, while the superheat control or the discharge superheat control is being performed, for example, when the operation of one of the indoor units B is stopped while both the indoor units A and B are operating, the operating frequency of the compressor 1 becomes 10 Hz. When the above changes occur, the valve openings of the variable decompression devices 4A and 4B are controlled to operate at the initial values of the valve openings shown in Table 1.

In the above description, a multi-room air conditioner in which two outdoor units A and B are connected to one outdoor unit C has been described as an example, but the number of indoor units is not necessarily two. The present invention is not limited to this. Even when there are three or more indoor units, the system can be controlled with substantially the same control contents based on the same concept.

Further, the indoor heat exchanger intermediate temperature sensor 16
The mounting positions of the intermediate temperature sensors A, 16B, and the outdoor heat exchanger intermediate temperature sensor 12 are not necessarily intermediate, and may be any positions that can achieve the purpose of detecting the saturation temperature of the refrigerant as the evaporator or the condenser, and therefore, are quite wide. Is selectable.

Further, in the embodiment of the present invention, the variable pressure reducing devices 4A and 4B are connected to the outdoor unit C as shown in FIG.
The indoor heat exchangers 5 of the indoor units A and B have been described.
A, 5B and the connecting pipes 6A, 6B may be arranged in the middle of the pipe route.

In the embodiment of the present invention, the superheat control during the cooling operation and the discharge superheat control, and the superheat control during the heating operation and the discharge superheat control are described separately. Can be adopted independently and individually, or in combination with each other, for a cooling only machine, a cooling / heating machine or the like.

[0117]

[0118]

The present invention is embodied in the form described above, and has the following effects. Claim 1
According to the described invention, the indoor heat exchanger intermediate temperature detecting means is provided in the middle of the refrigerant path pipe of each indoor heat exchanger, and the indoor heat exchanger outlet temperature detecting means is provided at the outlet of the refrigerant path pipe of each indoor heat exchanger. A superheat degree calculating means for calculating a superheat degree of each indoor heat exchanger based on each of the detected pipe temperatures, and a compressor operating frequency detecting means for detecting an operating frequency of the compressor. The valve opening control mode table in which the valve opening value of the variable pressure reducing device is set from the numerical value of the machine operating frequency and the calculated value of the superheat calculating means, the numerical value of the compressor operating frequency, and the calculation of the superheat calculating means A valve opening control mode determining means for determining a control mode of the variable pressure reducing device based on the control value, and a valve opening value from a valve opening control mode table based on the control mode determined by the valve opening control mode determining means. To By controlling the degree of superheating of the refrigeration cycle during cooling operation by adjusting the valve opening of the variable pressure reducing device, the compressor Dew condensation on the indoor fan can be prevented while maintaining the high efficiency operation of the refrigeration cycle over the entire operation frequency range.

According to the invention of claim 2, the outdoor heat exchanger intermediate temperature detecting means is provided in the middle of the refrigerant path pipe of the outdoor heat exchanger, and the compressor discharge temperature detecting means is provided on the discharge pipe side of the compressor. A discharge superheat degree calculating means for calculating a discharge superheat degree of the refrigeration cycle based on each detected pipe temperature; and a compressor operation frequency detection means for detecting a compressor operation frequency, and the detected compressor operation frequency is provided. And the valve opening control mode table in which the valve opening of the variable pressure reducing device is set from the calculated value of the discharge superheat calculating means, the numerical value of the compressor operating frequency, and the calculated value of the discharge superheat calculating means. A valve opening control mode determining means for determining a control mode of the variable pressure reducing device; a valve opening value is determined based on the control mode determined by the valve opening control mode determining means; By controlling the degree of valve opening and controlling the degree of superheat of the refrigeration cycle during the cooling operation, the refrigeration cycle can be controlled over the entire operating frequency range of the compressor, even if the pipe length of the indoor unit differs during the cooling operation. The liquid compression operation of the compressor can be prevented while maintaining the high efficiency operation.

According to the third aspect of the present invention, the indoor heat exchanger intermediate temperature detecting means is provided in the middle of the refrigerant path pipe of each indoor heat exchanger, and the indoor path is provided at the outlet of the refrigerant path pipe of each indoor heat exchanger. Heat exchanger outlet temperature detection means, an outdoor heat exchanger intermediate temperature detection means in the middle of the refrigerant path piping of the outdoor heat exchanger, and a compressor discharge temperature detection means provided on the discharge pipe side of the compressor,
A superheat degree calculating means for calculating the degree of superheat of each indoor heat exchanger based on the detected pipe temperatures and a discharge superheat degree calculating means for calculating the discharge superheat degree of the refrigeration cycle are provided. A valve in which a valve opening value of a variable pressure reducing device is set from a value of the detected compressor operating frequency and a value calculated by the superheat degree calculation means and the discharge superheat degree calculation means. An opening degree control mode table, a valve opening degree control mode determining means for determining a control mode of the variable pressure reducing device based on a value of the compressor operating frequency and a calculated value of the superheat degree calculating means and the discharge superheat degree calculating means, By determining the valve opening value based on the determined control mode and adjusting the valve opening of the variable pressure reducing device to control the degree of superheat and discharge superheat of the refrigeration cycle during the cooling operation, the cooling operation is controlled. Even when the piping length of the indoor unit differs, the high efficiency operation of the refrigeration cycle is maintained over the entire operating frequency range of the compressor, while preventing condensation on the indoor fan and preventing liquid compression operation of the compressor. it can.

According to the fourth aspect of the present invention, the outdoor heat exchanger intermediate temperature detecting means is provided in the middle of the refrigerant path pipe of the outdoor heat exchanger, and the outdoor heat exchanger is provided at the outlet of the refrigerant path pipe of the outdoor heat exchanger. A compressor outlet temperature detecting means, a superheat degree calculating means for calculating a superheat degree of the outdoor heat exchanger based on each detected pipe temperature, and a compressor operating frequency detecting means for detecting an operating frequency of the compressor. The valve opening control mode table in which the valve opening value of the variable pressure reducing device is set from the detected value of the compressor operating frequency and the value calculated by the superheat calculating means, and the value of the compressor operating frequency and the overheating Valve opening control mode determining means for determining the control mode of the variable pressure reducing device based on the calculated value of the degree calculating means, and the valve opening value is determined based on the control mode determined by the valve opening control mode determining means. Decision By adjusting the valve opening of the variable decompression device to control the degree of superheating of the refrigeration cycle during the heating operation, the entire operation of the compressor can be performed even when the pipe length of the indoor unit differs during the heating operation. Over the frequency range, while maintaining the high efficiency operation of the refrigeration cycle, it is possible to prevent an excessive rise in the discharge gas temperature of the compressor and prevent the refrigeration cycle from overheating.

According to the fifth aspect of the present invention, the indoor heat exchanger intermediate temperature detecting means is provided in the refrigerant passage pipe of each indoor heat exchanger, and the compressor discharge temperature detecting means is provided on the discharge pipe side of the compressor. Provided, a discharge superheat degree calculating means for calculating the discharge superheat degree of the refrigeration cycle, and a compressor operating frequency detecting means for detecting the operating frequency of the compressor, based on the detected respective pipe temperatures. A valve opening control mode table in which the valve opening of the variable pressure reducing device is set from the value of the compressor operating frequency and the calculated value of the discharge superheat calculating means, and the calculation of the numerical value of the compressor operating frequency and the discharge superheat calculating means A valve opening control mode determining means for determining a control mode of the variable pressure reducing device based on the value, and a valve opening control mode table based on the control mode determined by the valve opening control mode determining means. By controlling the valve opening of the variable pressure reducing device to control the discharge superheat of the refrigeration cycle during the heating operation, the difference in the indoor unit piping length during the heating operation is determined. On the other hand, the liquid compression operation of the compressor can be prevented while maintaining the high efficiency operation of the refrigeration cycle over the entire operation frequency range of the compressor.

According to the invention of claim 6, the outdoor heat exchanger intermediate temperature detecting means is provided in the middle of the refrigerant path pipe of the outdoor heat exchanger, and the outdoor heat exchanger is provided at the outlet of the refrigerant path pipe of the outdoor heat exchanger. The outlet temperature detecting means, the indoor heat exchanger intermediate temperature detecting means in the middle of the refrigerant path piping of each indoor heat exchanger, and the compressor discharge temperature detecting means on the discharge pipe side of the compressor are provided. A superheat degree calculating means for calculating the superheat degree of the outdoor heat exchanger based on the respective pipe temperatures, and a discharge superheat degree calculation means for calculating the discharge superheat degree of the refrigeration cycle, and a compressor for detecting the operating frequency of the compressor Valve opening control in which a valve opening value of the variable decompression device is set based on the detected compressor operating frequency and a value calculated by the superheat degree calculation means and the discharge superheat degree calculation means by providing an operation frequency detection means; Mode table A valve opening control mode determining means for determining a control mode of the variable pressure reducing device based on a value of the compressor operating frequency and a calculated value of the superheat degree calculating means and the discharge superheat degree calculating means. Based on the control mode determined by the above, the valve opening value is determined from the valve opening control mode table, and the degree of superheating and discharge superheating of the refrigeration cycle during the heating operation is adjusted by adjusting the valve opening of the variable pressure reducing device. The control prevents the liquid compression operation of the compressor while maintaining the high efficiency operation of the refrigeration cycle over the entire operation frequency range of the compressor, even if the pipe length of the indoor unit is different during the heating operation. In addition, it is possible to prevent the discharge gas temperature of the compressor from excessively rising, thereby preventing the refrigerating cycle from overheating.

According to the seventh aspect of the present invention, there is provided a superheat degree prioritizing means during the cooling operation and a discharge superheat degree prioritizing means during the heating operation. In the superheat degree control and the discharge superheat degree control of the refrigeration cycle, The superheat degree priority means gives priority to the superheat degree control over the discharge superheat degree control at the time of the cooling operation, and the discharge superheat degree control gives priority to the discharge superheat degree control at the time of the heating operation by the discharge superheat degree priority determination means. With this, the superheat degree control and the discharge superheat degree control are simultaneously adopted, so that the optimum superheat degree control and the optimum discharge superheat degree control can both be performed. That is, during the cooling operation, the superheat degree priority determination means is provided, so that even in one room, the discharge superheat degree control is in a standby state if the superheat degree control is being performed, and the superheat degree priority control always gives priority to the indoor fan. During the heating operation, if even one room is under discharge superheat control, the superheat control is in a standby state, and the discharge superheat priority control always gives priority to preventing the liquid compression operation of the compressor. Can be performed.

[Brief description of the drawings]

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

FIG. 2 is a control block diagram of the multi-room air conditioner according to the embodiment of the present invention.

FIG. 3 is a characteristic diagram showing a basic concept of superheat control of the multi-room air conditioner according to the embodiment of the present invention.

FIG. 4 is a characteristic diagram showing a basic concept of discharge superheat control of the multi-room air conditioner according to the embodiment of the present invention.

FIG. 5 is a flowchart showing superheat degree control during cooling operation of the multi-room air conditioner according to the embodiment of the present invention.

FIG. 6 is a flowchart showing discharge superheat degree control during cooling operation of the multi-room air conditioner according to the embodiment of the present invention.

FIG. 7 is a control flowchart showing superheat degree control during heating operation of the multi-room air conditioner according to the embodiment of the present invention.

FIG. 8 is a control flowchart showing discharge superheat degree control during a heating operation of the multi-room air conditioner according to the embodiment of the present invention.

FIG. 9 is a refrigeration cycle diagram of a conventional multi-room air conditioner.

[Explanation of symbols]

 1 compressor 2 four-way valve 3 outdoor heat exchanger 4A, 4B variable decompression device 5A, 5B indoor heat exchanger 6A, 6B, 7A, 7B connection piping 8 outdoor fan 9 outdoor suction temperature sensor 10 discharge piping temperature sensor 11 outdoor heat Exchanger outlet temperature sensor 12 Outdoor heat exchanger intermediate temperature sensor 13A, 13B Indoor fan 14A, 14B Indoor suction temperature sensor 15A, 15B Indoor heat exchanger outlet temperature sensor 16A, 16B Indoor heat exchanger intermediate temperature sensor 20 Indoor heat exchanger Intermediate temperature detecting means 21 Indoor heat exchanger outlet temperature detecting means 22 Outdoor heat exchanger intermediate temperature detecting means 23 Outdoor heat exchanger outlet temperature detecting means 24 Compressor discharge temperature detecting means 25 Operating mode determining means 27 Superheat degree calculating means 28 Discharge Superheat degree calculation means 29 Superheat degree priority determination means 30 Discharge superheat degree priority determination means 31 Valve opening control mode determination Setting means 32 compressor operating frequency detecting means 33 valve opening degree control mode table 34 variable pressure reducing apparatus valve opening changing means 35 variable pressure reducing apparatus output means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Teruo Fujisha 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Yoji Takanashi 1006 Kazuma Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F term (reference) 3L060 AA01 CC04 CC19 DD05 EE04 EE09

Claims (7)

[Claims] 1. An outdoor unit having a variable frequency control type compressor and an outdoor heat exchanger, a plurality of indoor units having an indoor heat exchanger, and a variable type corresponding to each of the indoor units. A pressure reducing device is provided in the refrigerant path piping of the outdoor heat exchanger and each indoor heat exchanger, and in a refrigeration cycle connected by a connection pipe, the valve opening of the variable pressure reducing device is controlled by a control signal. A variable pressure reducing device, further provided in the middle of the refrigerant path piping of each of the indoor heat exchangers, an indoor heat exchanger intermediate temperature detecting means for detecting the temperature of the refrigerant path piping, and a refrigerant of each of the indoor heat exchangers An indoor heat exchanger outlet temperature detecting means is provided at an outlet of the path pipe and detects the temperature of the refrigerant path pipe, and the temperature is detected by the indoor heat exchanger intermediate temperature detecting means and the indoor heat exchanger outlet temperature detecting means. Depends on each piping temperature A superheat degree calculating means for calculating the degree of superheat of each of the indoor heat exchangers; a compressor operating frequency detecting means for detecting an operating frequency of the compressor; and a numerical value of the compressor operating frequency and the superheat degree calculating means. From the calculated value, a valve opening control mode table in which the valve opening value of the variable pressure reducing device is set, a numerical value of the compressor operating frequency detected by the compressor operating frequency detecting means, and the superheat degree calculating means A valve opening control mode determining means for determining a control mode of the variable pressure reducing device based on the calculated value of the valve opening control mode determining means. Based on the control mode determined by the valve opening control mode determining means, the valve is controlled from the valve opening control mode table. A multi-chamber air conditioner that determines an opening value and controls the valve opening of the variable decompression device by a variable decompression device valve opening changing means to control the degree of superheating of the refrigeration cycle during cooling operation. Machine of the control device. 2. An outdoor unit having a variable frequency control type compressor and an outdoor heat exchanger, a plurality of indoor units having an indoor heat exchanger, and a variable type corresponding to each of the indoor units. A pressure reducing device is provided in the refrigerant path piping of the outdoor heat exchanger and each indoor heat exchanger, and in a refrigeration cycle connected by a connection pipe, the valve opening of the variable pressure reducing device is controlled by a control signal. A variable pressure reducing device, further provided in the middle of the refrigerant path piping of the outdoor heat exchanger, an outdoor heat exchanger intermediate temperature detecting means for detecting the temperature of the refrigerant path piping, and provided on the discharge pipe side of the compressor. A compressor discharge temperature detecting means for detecting a pipe temperature at a location provided; and an outdoor heat exchanger intermediate temperature detecting means and a compressor discharge temperature detecting means. Over-discharge Discharge superheat calculating means for calculating the degree of operation, compressor operating frequency detecting means for detecting the operating frequency of the compressor, a numerical value of the compressor operating frequency, and the variable expression from the calculated value of the discharge superheat calculating means. The valve opening control mode table in which the valve opening of the pressure reducing device is set, the numerical value of the compressor operating frequency detected by the compressor operating frequency detecting means, and the variable value calculated by the calculated value of the discharge superheat calculating means. A valve opening control mode determining means for determining a control mode of the pressure reducing device is provided, and a valve opening value is determined from the valve opening control mode table based on the control mode determined by the valve opening control mode determining means. A variable pressure reducing device valve opening changing means adjusts a valve opening of the variable pressure reducing device to control a discharge superheat degree of a refrigeration cycle during a cooling operation. Apparatus. 3. An outdoor unit having a variable frequency control type compressor and an outdoor heat exchanger, a plurality of indoor units having an indoor heat exchanger, and a variable type corresponding to each of the indoor units. A pressure reducing device is provided in the refrigerant path piping of the outdoor heat exchanger and each indoor heat exchanger, and in a refrigeration cycle connected by a connection pipe, the valve opening of the variable pressure reducing device is controlled by a control signal. A variable pressure reducing device, further provided in the middle of the refrigerant path piping of each of the indoor heat exchangers, an indoor heat exchanger intermediate temperature detecting means for detecting the temperature of the refrigerant path piping, and a refrigerant of each of the indoor heat exchangers An indoor heat exchanger outlet temperature detecting means provided at the outlet of the path pipe and detecting the temperature of the refrigerant path pipe, and provided in the middle of the refrigerant path pipe of the outdoor heat exchanger and detecting the temperature of the refrigerant path pipe Outdoor heat exchanger intermediate temperature detection And a compressor discharge temperature detecting means provided on the discharge pipe side of the compressor and detecting a pipe temperature at the provided location. The indoor heat exchanger intermediate temperature detecting means and the indoor heat exchanger outlet temperature detecting means are provided. Means for calculating the degree of superheat of each of the indoor heat exchangers based on the respective pipe temperatures detected by the means, an outdoor heat exchanger intermediate temperature detecting means and a compressor discharge temperature detecting means, respectively. Discharge superheat degree calculating means for calculating the discharge superheat degree of the refrigeration cycle based on the pipe temperature, compressor operating frequency detecting means for detecting the operating frequency of the compressor, a numerical value of the compressor operating frequency and the superheat degree A valve opening control mode table in which a valve opening value of the variable pressure reducing device is set based on a calculation value of the calculation means and the discharge superheat degree calculation means; And a valve opening control mode determining means for determining the control mode of the variable pressure reducing device based on the numerical value of the compressor operating frequency detected by the above and the calculated values of the superheat degree calculating means and the discharge superheat degree calculating means. The valve opening value is determined from the valve opening control mode table based on the control mode determined by the degree control mode determining means, and the valve opening degree of the variable pressure reducing apparatus is determined by the variable pressure reducing apparatus valve opening changing means. A multi-room air conditioner control device that controls the degree of superheat and discharge superheat of the refrigeration cycle during cooling operation by adjusting the temperature. 4. An outdoor unit having a variable frequency control type compressor and an outdoor heat exchanger, a plurality of indoor units having an indoor heat exchanger, and a variable type corresponding to each of the indoor units. A pressure reducing device is provided in the refrigerant path piping of the outdoor heat exchanger and each indoor heat exchanger, and in a refrigeration cycle connected by a connection pipe, the valve opening of the variable pressure reducing device is controlled by a control signal. A variable pressure reducing device, further provided in the middle of the refrigerant path pipe of the outdoor heat exchanger, an outdoor heat exchanger intermediate temperature detecting means for detecting the temperature of the refrigerant path pipe, and a refrigerant path pipe of the outdoor heat exchanger And an outdoor heat exchanger outlet temperature detecting means for detecting the temperature of the refrigerant path piping, provided by the outdoor heat exchanger intermediate temperature detecting means and the outdoor heat exchanger outlet temperature detecting means. Depending on the piping temperature, Superheat degree calculation means for calculating the degree of superheat of the outdoor heat exchanger, compressor operation frequency detection means for detecting the operation frequency of the compressor, a numerical value of the compressor operation frequency and a calculation value of the superheat degree calculation means From the above, the valve opening control mode table in which the valve opening value of the variable pressure reducing device is set, the numerical value of the compressor operating frequency detected by the compressor operating frequency detecting means, and the calculation of the superheat degree calculating means A valve opening control mode determining means for determining a control mode of the variable pressure reducing device based on the value; a valve opening control mode table based on the control mode determined by the valve opening control mode determining means; Determine the value, by adjusting the valve opening of the variable pressure reducing device by the variable pressure reducing device valve opening changing means, during the heating operation, the multi-room air conditioner that controls the degree of superheat of the refrigeration cycle Control device. 5. An outdoor unit having a variable frequency control type compressor and an outdoor heat exchanger, a plurality of indoor units having an indoor heat exchanger, and a variable type corresponding to each of the indoor units. A pressure reducing device is provided in the refrigerant path piping of the outdoor heat exchanger and each indoor heat exchanger, and in a refrigeration cycle connected by a connection pipe, the valve opening of the variable pressure reducing device is controlled by a control signal. A variable pressure reducing device, further provided in the middle of the refrigerant path piping of each of the indoor heat exchangers, an indoor heat exchanger intermediate temperature detecting means for detecting the temperature of the refrigerant path piping, and a discharge pipe side of the compressor. Provided, the compressor discharge temperature detecting means for detecting the pipe temperature of the provided location, and the respective pipe temperatures detected by the indoor heat exchanger intermediate temperature detecting means and the compressor discharge temperature detecting means. Refrigeration cycle spitting Discharge superheat degree calculating means for calculating the degree of superheat, compressor operating frequency detecting means for detecting the operating frequency of the compressor, the variable value from the numerical value of the compressor operating frequency, and the calculated value of the discharge superheat degree calculating means. The valve opening control mode table in which the valve opening of the pressure reducing device is set, the numerical value of the compressor operating frequency detected by the compressor operating frequency detecting means, and the variable value calculated by the calculated value of the discharge superheat calculating means. A valve opening control mode determining means for determining a control mode of the pressure reducing device, and a valve opening value is determined from the valve opening control mode table based on the control mode determined by the valve opening control mode determining means. A multi-chamber air conditioner that controls the degree of superheating of the refrigeration cycle during heating operation by adjusting the valve opening of the variable pressure reducing device by means of the variable pressure reducing device valve opening changing means. The control device. 6. An outdoor unit having a variable frequency control type compressor and an outdoor heat exchanger, a plurality of indoor units having an indoor heat exchanger, and a variable type corresponding to each of the indoor units. A pressure reducing device is provided in the refrigerant path piping of the outdoor heat exchanger and each indoor heat exchanger, and in a refrigeration cycle connected by a connection pipe, the valve opening of the variable pressure reducing device is controlled by a control signal. A variable pressure reducing device, further provided in the middle of the refrigerant path pipe of the outdoor heat exchanger, an outdoor heat exchanger intermediate temperature detecting means for detecting the temperature of the refrigerant path pipe, and a refrigerant path pipe of the outdoor heat exchanger , An outdoor heat exchanger outlet temperature detecting means for detecting the temperature of the refrigerant path piping, and provided in the middle of the refrigerant path pipes of the indoor heat exchangers for detecting the temperature of the refrigerant path pipes Each indoor heat exchanger intermediate temperature detection And a compressor discharge temperature detecting means provided on the discharge pipe side of the compressor and detecting a pipe temperature at the provided location, and detecting the intermediate temperature of the outdoor heat exchanger and detecting the temperature of the outlet of the outdoor heat exchanger. The superheat degree calculating means for calculating the superheat degree of the outdoor heat exchanger based on the respective pipe temperatures detected by the means, the indoor heat exchanger intermediate temperature detecting means, and the compressor discharge temperature detecting means. A discharge superheat degree calculating means for calculating a discharge superheat degree of the refrigeration cycle, a compressor operation frequency detection means for detecting an operation frequency of the compressor, a numerical value of the compressor operation frequency and the superheat A valve opening control mode table in which a valve opening value of the variable decompression device is set based on the operation values of the degree calculating means and the discharge superheat degree calculating means; Valve opening degree control mode determining means for determining the control mode of the variable pressure reducing device based on the value of the compressor operating frequency detected by the stage and the calculated values of the superheat degree calculating means and the discharge superheat degree calculating means; Based on the control mode determined by the opening control mode determining means, a valve opening value is determined from the valve opening control mode table, and the valve opening of the variable pressure reducing apparatus is changed by the variable pressure reducing apparatus valve opening changing means. A control device for a multi-room air conditioner that controls the degree of superheat and discharge superheat of the refrigeration cycle during heating operation by adjusting the degree of heating. 7. A superheat degree priority judging means for cooling operation and a discharge superheat degree priority judgment means for heating operation. In superheat degree control and discharge superheat degree control of the refrigeration cycle, the superheat degree priority judgment means performs the cooling operation. The superheat degree control is prioritized over the discharge superheat degree control during the operation, and the discharge superheat degree control is prioritized over the superheat degree control during the heating operation by the discharge superheat degree priority determination means. The control device of the multi-room air conditioner according to the above.