JPH04190054A - Multi-chamber type air conditioner - Google Patents

Abstract

PURPOSE:To prevent a reduction in heating capability caused by an excessive increasing of discharging temperature or a reduction in suction pressure even under an excessive operating state by a method wherein a controlling interval of a controller for an outdoor electric expansion valve is longer than a controlling interval of an inverter controller. CONSTITUTION:During a heating operation, a condensing pressure is detected. When the condensing pressure is higher than a predetermined pressure, a variable capability compressor 2 is instructed from the inverter controller 13 so as to instruct it to decrease an operating frequency and if the pressure is lower, it is instructed to increase. This control is repeated for every one minute. A piping temperature between the indoor device 7 and an outdoor electric expansion valve 5 is detected. If it is higher than a predetermined temperature, an instruction to close by a predetermined degree of opening in respect to the expansion valve 5 from an outdoor electric expansion valve control device 15' and if it is lower, it is instructed to open. This control is repeated for every two minutes. That is, a condensing pressure with a fast responding speed is approached to a set value with a short interval and at the same time a slow responding sub-cooled degree is approached gradually to a set value at a long interval, resulting in that it is possible to prevent over-increasing of discharging temperature under an excessive operation state or a reduction in suction pressure.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a multi-room air conditioner.

Conventional technology In recent years, individual distributed air conditioning has been progressing in building air conditioning.
The individualization of multi-room air conditioners as known from Japanese Unexamined Patent Publication No. 1-212870 has been progressing.

The conventional technology will be described below with reference to the drawings.

4 to 6, 1 is an outdoor unit of a multi-room air conditioner, which is composed of a variable capacity compressor 2, a four-way valve 3, an outdoor heat exchanger 4, an outdoor electric expansion valve 5, and an outdoor fan 6. ing. Reference numeral 7 denotes indoor units, which are connected in parallel to the outdoor unit 1, and each has an indoor electric expansion valve 8, an indoor heat exchanger 9, and an indoor fan 10.
(Hereinafter, when distinguishing between indoor units 7, subscripts A and B are used.

(I will add C and D). Reference numeral 11 denotes a pressure detector, which is installed in the pipe inside the outdoor unit 1 between the four-way valve 3 and the indoor heat exchanger 9. 12 is an inverter, and an inverter controller 13 is operated according to the refrigerant pressure detected by the pressure detector 11.
As a result, the output frequency of the inverter 12 is changed, and the operating frequency of the variable capacity compressor 2 is changed. Reference numeral 14 denotes a refrigerant temperature detector installed in the pipe between the indoor unit 7 and the outdoor electric expansion valve 5. Depending on the detected refrigerant temperature, the outdoor electric expansion valve controller 15 controls the opening degree of the outdoor electric expansion valve 5. is controlled. 16
is an air temperature detector that detects the temperature of the intake air of the indoor unit 7, and this detected air temperature and the remote controller (
The air conditioning load of the room is calculated by the air conditioning load calculator 17 based on the room temperature setting value set by a remote controller (not shown, hereinafter referred to as a remote control), and the indoor electric expansion valve controller 18 is used according to the calculated air conditioning load. The opening degree of the indoor electric expansion valve 8 is controlled.

The operation of the multi-room air conditioner configured as described above will be explained by taking heating operation as an example.

The high-temperature, high-pressure refrigerant discharged from the variable capacity compressor 2 flows into the indoor heat exchanger 9 through the west valve 3, condenses and liquefies, and is depressurized by the outdoor electric expansion valve 5 via the indoor electric expansion valve 8t. It is evaporated in the outdoor heat exchanger 4, passes through the west valve 3 again, and returns to the variable capacity compressor 2.

At this time, the operating frequency of the variable capacity compressor 2 changes according to the air conditioning load at that time.The detected pressure (Sl) detected by the pressure detector 11 (condensing pressure during heating) is set at a predetermined level. The inverter 12 is controlled by the inverter controller 13 so that the pressure is maintained (S2, S3) (54,
S5) When the detected pressure is higher than a predetermined pressure, the control is performed in the direction of a lower frequency, and when it is lower than a predetermined pressure, the control is performed in the direction of a higher frequency.

Further, the opening degree of the outdoor electric expansion valve 5 is determined by the piping temperature (S6) between the indoor unit 7 and the outdoor electric expansion valve 5 detected by the refrigerant temperature detector 14, which changes depending on the operating state at that time.
When the detected temperature is higher than the predetermined temperature, the outdoor electric expansion valve controller 15 sets the temperature to a predetermined temperature (to a predetermined degree of supercooling) (S7, S8); When it is low, it is controlled in the open direction (S9.510), and after waiting for one minute, the above control is repeated. (S1 Furthermore, the opening degree of the indoor electric expansion valve 8 is determined by the room temperature setting value set by the remote control and the indoor unit 7 detected by the air temperature detector 16.
From the temperature of the intake air (512, 513), the air conditioning load calculator 17 calculates the air conditioning load of the room (514), and according to the calculated air conditioning load, when the air conditioning load is large, the air conditioning load is opened, and when it is small, it is closed. (S15.516
).

The operating frequency of the variable capacity compressor 2, which is a control element on the outdoor unit side, and the opening degree of the outdoor electric expansion valve 5, and the opening degree of the indoor electric expansion valve 8, which is a control element on the indoor unit side, are independent of each other. controlled.

Problems to be Solved by the Invention However, in the above configuration, the operating frequency of the variable capacity compressor 2 and the control interval of the opening degree of the outdoor electric expansion valve 5 are the same.

Therefore, there are no problems under normal operating conditions, but during transient operating conditions, problems such as an excessive rise in the discharge all temperature and a decrease in heating capacity due to a decrease in suction pressure occur.

In other words, during start-up operation, which is a transient operating state, or when the operating state suddenly changes (for example, suddenly changing from operating four indoor units 7 to operating one indoor unit 7), the degree of supercooling will vary depending on the speed of change in condensing pressure. Since the speed of change in the variable capacity compressor 2 is slow, if the operating frequency of the variable capacity compressor 2 and the opening degree of the outdoor electric expansion valve 5 are controlled at the same interval, the condensing pressure will change even though the degree of supercooling is not nearly stable. As a result, even if the opening degree of the outdoor electric expansion valve 5 is reduced, a reverse response occurs in which the degree of subcooling decreases, and the opening degree of the outdoor electric expansion valve 5 becomes too small than the designed opening degree, and as time passes, a transient state occurs. When the outdoor electric expansion valve 5 returns to its normal state, the opening degree of the outdoor electric expansion valve 5 does not return to normal, and the outdoor electric expansion valve 5 is throttled too much, resulting in an excessive rise in discharge temperature and a decrease in suction pressure, resulting in a significant decrease in reliability and comfort. I had an issue.

The present invention solves the above-mentioned conventional problems, and aims to improve reliability and comfort by preventing excessive rise in discharge temperature and reduction in heating capacity due to drop in suction pressure even in transient operating conditions. be.

Means for Solving the Problems In order to solve the above eight problems, the present invention provides an outdoor unit equipped with a compressor whose capacity is variable by an inverter, a four-way valve, an outdoor heat exchanger, an outdoor electric expansion valve, and an indoor electric expansion valve. , an inverter in which a plurality of indoor units, each equipped with an indoor heat exchanger, are connected in parallel, a pressure detector is provided between the indoor units and piping with a four-way valve open, and the frequency of the inverter is controlled according to the detected pressure. a controller, a refrigerant temperature detector installed in a pipe between the indoor unit and the outdoor electric expansion valve to detect the refrigerant temperature, and an outdoor electric expansion valve controller to control the opening degree of the outdoor electric expansion valve according to the detected temperature. , an air temperature detector that detects the intake air temperature of the indoor unit, an air conditioning load calculator that calculates from the detected intake air temperature and the room temperature setting value, and an indoor unit that controls the indoor electric expansion valve opening according to the air conditioning load. An electric expansion valve controller is provided, and the control interval of the outdoor electric expansion valve controller is longer than the control interval of the inverter controller.

Effect The present invention has the above-described configuration, and has the ability to control the degree of supercooling, which changes slowly, in transient operating conditions such as during start-up or when there is a sudden change between eight operating states, that is, to control the opening degree of the outdoor expansion valve. Control the operating frequency of the variable compressor to stabilize the condensing pressure before carrying out the operation to prevent excessive throttling of the outdoor electric expansion valve and to prevent an excessive rise in discharge temperature or a drop in suction pressure. It is something to do.

EXAMPLE A multi-room air conditioner according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 3, but since the configuration is the same as the conventional example, detailed explanation thereof will be omitted. .

FIG. 3 shows the control intervals of the inverter controller 13 that controls the operating frequency of the variable capacity compressor 2, which is an outdoor unit side control element, and the outdoor electric expansion valve controller 15 that controls the opening degree of the outdoor electric expansion valve 5. The control interval of the inverter controller 13 is set to 1 minute, and the control interval of the outdoor electric expansion valve controller 15' is set to 1 minute.
The control interval of the outdoor electric expansion valve controller 15' is set to 2 minutes, and the control interval of the outdoor electric expansion valve controller 15' is made longer than that of the inverter controller 13.

Next, the operation of the above configuration will be explained using heating operation as an example. Note that the operation of the refrigerant system is the same as that of the conventional example, so a description thereof will be omitted.

When the multi-room air conditioner is operated, first the pressure detector 11
Detect the detected pressure at that time (condensing pressure during heating) (Sl), compare the detected pressure with a preset predetermined pressure (S2, S3), and if the detected pressure is higher, the inverter controller 13 The variable capacity compressor 2 is instructed to lower its operating frequency via the inverter 12, and if it is lower, it is instructed to increase its operating frequency (S4, S5). This control is repeated every minute (S12).

Furthermore, the pipe temperature between the indoor unit 7 and the outdoor electric expansion valve 5 at that time is detected by the refrigerant temperature detector 14 (S7), and the detected temperature is compared with a predetermined temperature set in advance (S8,
S9) If the detected temperature is higher, the outdoor electric expansion valve controller 15 instructs the outdoor electric expansion valve 5 to open to a predetermined degree; if the detected temperature is lower, the outdoor electric expansion valve controller 15 instructs the outdoor electric expansion valve 5 to open to a predetermined degree.
S10.5ll), and this control is repeated every two minutes (S6).

Next, the indoor electric expansion valve 8 is the same as the conventional example, and is controlled independently of the outdoor unit side control element, and the indoor unit detects the room temperature setting value set by the remote control and the air temperature detector 16. The air conditioning load of the room is calculated by the air conditioning load calculator 17 from the temperature of the intake air in step 7, and the opening degree of the indoor electric expansion valve 80 is determined by the indoor electric expansion valve controller 18 according to the calculated air conditioning load. When the air conditioning load is large, it is controlled in the open direction, and when it is small, it is controlled in the closed direction.

At this time, in the outdoor unit side control element, the control interval of the outdoor electric expansion valve 5 that controls the degree of supercooling is as long as the control interval of the operating frequency of the variable capacity compressor 2 that controls the condensing pressure. This corresponds to the fact that the rate of change in is slower than the rate of change in condensation pressure.

That is, the condensing pressure, which has a fast response, is brought closer to the set value quickly in a short interval, and the degree of supercooling, which has a slow response, is slowly brought closer to the set value in a long interval while responding to the condensing pressure that is becoming stable.

Therefore, unlike in the past, a phenomenon such as excessive throttling of the outdoor electric expansion valve 5 does not occur during transient operating conditions, and comfort is reduced due to a decrease in reliability of the equipment due to excessive rise in discharge temperature and a decrease in capacity due to decrease in suction pressure. It is possible to prevent such things from happening.

In this embodiment, the control timing of the inverter controller 13 and the control timing of the outdoor electric expansion valve controller 15' are synchronized, but the two control timings may be shifted so that they are not synchronized.

Effects of the Invention As is clear from the above explanation, the present invention provides an outdoor unit equipped with a compressor whose capacity is variable by an inverter, a four-way valve, an outdoor heat exchanger, and an outdoor electric expansion valve, an indoor electric expansion valve, and an indoor heat exchanger. A plurality of indoor units, each equipped with an exchanger, are connected in parallel, a pressure detector is provided in the piping between the indoor units and the four-way valve, and the frequency of the inverter is controlled according to the detected pressure. a refrigerant temperature detector installed in the piping between the indoor unit and the open outdoor electric expansion valve to detect the refrigerant temperature; an outdoor electric expansion valve controller that controls the opening degree of the outdoor electric expansion valve according to the detected temperature; An air temperature detector that detects the intake air temperature of the machine, an air conditioning load calculator that calculates from the detected intake air temperature and room temperature set value, and an indoor electric controller that controls the indoor electric expansion valve opening according to the air conditioning load. An expansion valve controller is provided, and the control interval of the outdoor electric expansion valve controller is made longer than the control interval of the inverter controller, so that the outdoor electric expansion valve can be throttled not only during normal operation but also during transient operating conditions. It is possible to prevent a phenomenon such as overheating from occurring, and to prevent a decrease in comfort due to a decrease in the reliability of the equipment due to an excessive rise in the bath temperature or a decrease in performance due to a decrease in suction pressure.

[Brief explanation of the drawing]

Fig. 1 is a refrigeration cycle diagram of a multi-room air conditioner that is an embodiment of the present invention, Fig. 2 is a control flow chart of the outdoor unit side control elements of the air conditioner shown in Fig. 1, and Fig. 3 is a Timing chart of the outdoor unit side control elements shown in Figure 2, 4th
The figure shows the refrigeration cycle section of a conventional multi-room air conditioner, Figure 5 is a control flowchart of the outdoor unit side control elements of the air conditioner shown in Figure 4, and Figure 6 shows the air conditioner shown in Figure 4. 2 is a control flowchart of the indoor expansion valve of the machine. 1... Outdoor unit, 2... Variable capacity compressor, 3... Four-way valve, 4... Outdoor heat exchanger, 5...・Outdoor electric expansion valve, 7... Indoor unit, 8... Indoor electric expansion valve, 9... Indoor heat exchanger, 11... Pressure detector , 12...
... Inverter, 13 ... Inverter controller, 14 ... Refrigerant temperature detector, 15 ...
Outdoor electric expansion valve controller, 16... Air temperature detector, 17... Air load calculator, 18...
・Indoor electric expansion valve controller. Name of agent: Patent attorney Akira Okaji Two idiots Figure 2

Claims (1)

[Claims] An outdoor unit equipped with a compressor whose capacity can be varied by an inverter, a four-way valve, an outdoor heat exchanger, and an outdoor electric expansion valve is connected in parallel with multiple indoor units each equipped with an indoor electric expansion valve and an indoor heat exchanger. A pressure detector is installed in the piping between the indoor unit and the four-way valve, and an inverter controller is installed in the piping between the indoor unit and the outdoor electric expansion valve to control the refrigerant temperature according to the detected pressure. an outdoor electric expansion valve controller that controls the opening degree of the outdoor electric expansion valve according to the detected temperature; an air temperature sensor that detects the suction air temperature of the indoor unit; An air conditioning load calculator that calculates from the air temperature and room temperature set value, and an indoor electric expansion valve controller that controls the opening degree of the indoor electric expansion valve according to the air conditioning load are provided. A multi-room air conditioner with a longer control interval for the electric expansion valve controller.