JPH0718933Y2 - Release controller for air conditioner - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial field of application) The present invention relates to an air conditioner in which a plurality of indoor units are connected to one outdoor unit, and in particular, the operation mode of the indoor unit. The present invention relates to a release control device for an air conditioner that eliminates the stoppage of the compressor and stabilizes the cycle in the case where is changed.

(Prior Art) A multi-air conditioner that operates a plurality of indoor units with one outdoor unit will be described with reference to FIG.

In FIG. 5, a is an outdoor unit, b ₁ and b ₂ are a plurality of indoor units, and the gas side and liquid side refrigerant pipes c ₁ , c ₂ ,
d ₁ and d ₂ are connected to the outdoor unit a via a packed valve e.

In the outdoor unit a, a variable capacity compressor f and a four-way valve g
, An outdoor heat exchanger h and its outdoor fan i, and a pressure reducing device j are provided, and two-way valves k ₁ and k ₂ are connected to the gas side refrigerant pipes c ₁ and c ₂ on the gas side, respectively, and the liquid side Two-way valves l ₁ and l ₂ are connected to the refrigerant pipes d ₁ and d ₂ on the liquid side, respectively.

The indoor units b ₁ and b _{2 respectively} include indoor heat exchangers m ₁ and m ₂ , heat exchange sensors n ₁ and n ₂ , indoor fans o ₁ and o _2, and an air temperature sensor that detects the air temperature in each room. p _1,2 are provided. Further, in the outdoor unit a, a release valve q that returns a part of the refrigerant discharged from the compressor f to the suction side via the four-way valve g is provided.

The refrigerant flow during the cooling operation is such that the high-temperature high-pressure refrigerant from the compressor f flows to the outdoor heat exchanger h via the four-way valve g as shown by the solid line arrow in FIG. The pressure is reduced in the device j, flows through the liquid-side two-way valves l ₁ and l ₂ to the indoor heat exchangers m ₁ and m ₂ of the indoor units b ₁ and b ₂ , and is evaporated there, and then the gas-side two-way. The flow returns to the compressor f through the valves k ₁ and k ₂ and the four-way valve g. Further, the flow of the refrigerant during the heating operation is in the reverse cycle, as shown by the dotted arrow in the figure,
The high-temperature high-pressure refrigerant from the compressor f flows from the four-way valve g through the gas-side two-way valves k ₁ and k ₂ to the indoor heat exchangers m ₁ and m ₂ , where it is condensed and then the liquid-side two-way valve l. _After passing through ₁ and l ₂ , the pressure is reduced by the pressure reducing device j, flows to the outdoor heat exchanger h, is evaporated there, and then returns to the compressor f through the four-way valve g.

In this air conditioner, for example, during two-room heating operation, if one side (indoor unit b ₁ side) mode change (thermo OFF by temperature sensor p ₁ and operation switch set OFF) is input, the capacity is An inverter device (not shown) that drives the modified compressor f lowers the operating frequency in order to reduce the amount of refrigerant circulation, and at the same time turns off the outdoor fan i to eliminate heat input, and after a certain period of time, one side A release control operation was performed in which the gas side and liquid side two-way valves k ₁ and l ₁ of the unit b ₁ were closed and the outdoor fan i was turned on.

(Problems to be solved by the invention) However, since the above-mentioned release control lowers the operating frequency and simultaneously turns off the outdoor fan i, during that period,
There is a problem that heat input disappears, the refrigerant pressure in the cycle decreases, the refrigerant pressure to the other outdoor heat exchanger m ₂ decreases, the heating capacity decreases, and the heating feeling is impaired.

After closing the gas-side and liquid-side two-way valves k ₁ and l ₁ of the one-side unit b ₁ and turning on the outdoor fan i, the other indoor heat exchanger m ₂
The amount of heat input is too large for the amount of heat released in the unit, the pressure in the cycle becomes high, the temperature of the indoor heat exchanger in the indoor unit rises, exceeds the set value, and the release valve q is opened and the frequency is adjusted. It could reach the high temperature release area, which is reduced. In this case, the frequency down of the mode change and the frequency down by the high temperature release are executed at the same time, and the frequency
There is a problem that the frequency drops to the Min frequency and the compressor is stopped.

The present invention has been made in view of the above circumstances, and an air conditioner that can comfortably maintain the heating effect on the side that continues to operate when the number of operating units decreases during heating operation of a plurality of indoor units. An object is to provide a release control device.

[Structure of Device] (Means and Actions for Solving Problems) In order to achieve the above object, the present invention has a variable capacity compressor and an outdoor fan whose capacity is variable by changing the operating frequency. , One outdoor unit that houses the outdoor heat exchanger, a plurality of indoor units that respectively house the indoor heat exchanger, and a plurality of units that control the supply of the refrigerant from the outdoor unit to each indoor unit for each indoor unit. A release valve that is provided with an on-off valve and that returns the refrigerant discharged from the variable capacity compressor to the suction side is provided, and when the temperature of the indoor heat exchanger of the operating indoor unit exceeds the first set value, the release valve In the release control device of the air conditioner, which opens the release valve and then closes the release valve when the temperature of the indoor heat exchanger drops below a second set value lower than the first set value, When the number of operating indoor units decreases during operation, the on-off valve corresponding to the indoor unit that is stopped from operation is closed and the release valve is opened, and the operating frequency of the compressor is lowered by a predetermined value The air volume of the outdoor fan is decreased or stopped according to the decrease, and the release valve that was opened when the number of operating units decreased is closed when the indoor heat exchanger temperature of the operating indoor unit drops below the second set value. By providing a control device, it is possible to appropriately suppress the high pressure increase in the refrigeration cycle when the number of units decreases, and to control the number of units reduction without interfering with the heating effect of the indoor unit that continues to operate.

(Embodiment) A preferred embodiment of a release control device for an air conditioner according to the present invention will be described below with reference to the accompanying drawings.

First, the refrigeration cycle of the present invention will be described with reference to FIG. In FIG. 1, 1 is an outdoor unit, 2a and 2b are indoor units, and the gas side piping 3 of each of the indoor units 2a and 2b
The a, 3b and the liquid side pipes 4a, 4b are connected to the outdoor unit 1 by the packed valve 5, respectively.

The outdoor unit 1 includes a variable capacity compressor 6 driven by an inverter device (not shown) having a variable output frequency, a four-way valve 7 for switching between heating and cooling, an outdoor heat exchanger 8, an outdoor fan 9 and its fan. Motor 10 and decompression device such as expansion valve
11 is provided, and the gas side refrigerant pipe 3 on the outdoor unit 1 side
a, 3b are connected to the gas side two-way valves 12a, 12b, and the liquid side refrigerant pipe 4
Liquid side two-way valves 13a and 13b are connected to a and 4b. Also the compressor 6
A release valve 14 that returns the discharged refrigerant to the suction side via the four-way valve 7 is connected to the. The indoor units 2a, 2b are respectively provided with indoor heat exchangers 15a, 15b and their heat exchange sensors 16a, 6b, indoor fans 17a, 17b, and air temperature sensors 18a, 18b for detecting the air temperature in each room. To be

The flow of the refrigerant during the cooling operation is such that the high-temperature high-pressure refrigerant from the compressor 6 flows to the outdoor heat exchanger 8 via the four-way valve 7 and is condensed there, as indicated by the solid line arrow in the figure. It is decompressed by the decompression device 11, flows through the liquid-side two-way valves 12a, 12b to the indoor heat exchangers 15a, 15b of the indoor units 2a, 2b, where it is heat-exchanged with indoor air and evaporated, and then on the gas side. Way valve 13a,
13b, the flow returns to the compressor 7 via the four-way valve 7. Further, the flow of the refrigerant during the heating operation is the reverse cycle, and as shown by the dotted arrow in the figure, the high-temperature high-pressure refrigerant from the compressor 6 is passed from the four-way valve 7 through the gas-side two-way valves 13a and 13b. After flowing into the indoor heat exchangers 15a and 15b, where it exchanges heat with the indoor air and condenses, it passes through the liquid side two-way valves 12a and 12b, is decompressed by the decompression device 11 and flows to the outdoor heat exchanger 8, where it evaporates. After that, the flow returns to the compressor 7 through the four-way valve 7.

In the refrigeration cycle of FIG. 1, when the number of operating indoor units 2a, 2b is changed during heating operation, that is, as shown in the figure, of the two indoor units 2a, 2b, for example, the indoor unit 2a side is the indoor temperature. When the operation is stopped by control or by the operation stop switch, the release valve
A control device 19 is provided which opens 14 for a predetermined time, lowers the operating frequency of the compressor 6 by a predetermined value, and lowers or stops the air volume of the outdoor fan 9 according to the lowering of the operating frequency.

A block diagram of the control device 19 will be described with reference to FIG.

First, the control device 19 has an inverter device that controls the compressor 6 so that the rotation speed is variable.
Is designed to drive. In this case, the current release control signal 20 and the overcurrent control signal 21 are input to the control device 19, and the current control is performed so that the compressor 6 is not overloaded. When the outdoor heat exchanger 8 is frosted during the heating operation, the defrosting control signal 22 for detecting the temperature of the outdoor heat exchanger 8 is input, and the four-way valve 7 is switched to the cooling cycle to perform the defrosting operation. It has become. Further, the control device 19 switches the rotation speed of the outdoor fan motor 10 to Hi, Lo, and stop,
Further, the gas side two-way valves 12a and 12b and the liquid side two-way valves 13a and 13b are opened and closed, and the release valve 14 is opened and closed. The opening / closing control of the release valve 14 is performed based on the temperature of the indoor heat exchanger in the indoor unit, and in order to prevent a high pressure rise when the temperature of the indoor heat exchanger exceeds the high temperature release point which is the first set value. The release valve 14 is opened to open the release valve 14, then the high pressure decreases due to the release valve 14 opening, and the temperature of the indoor heat exchanger drops. When this temperature falls below the second set value, the release valve 14 is closed. To achieve.

The control device 19 includes operation information of each of the indoor units 2a and 2b (cooling / heating, operation / stop, required operation frequency, each sensor 16a, 16b).
b, 18a, 18b detection signals, etc.) are input.

In the present invention, the control device 19 switches the air volume of the outdoor fan 9 in two stages according to the operating frequency of the compressor 6, that is, between the maximum frequency (Max Hz) and the minimum frequency (Min Hz). , Maz Hz to Hi setting, the outdoor fan 9 is controlled to be a strong wind (Hi), a weak wind between Hi setting and Lo setting, and to stop at the Lo setting and below (however, it remains Lo during cooling operation) At the same time, when the number of operating vehicles is reduced, the operating frequency up to that point is lowered by a predetermined value (α frequency) and the release valve 14 is operated for a predetermined time (return signal of high temperature release from the indoor unit in operation, that is, in operation). After the temperature of the indoor heat exchanger of the indoor unit reaches the high-temperature release area, the time until the signal that is output when the temperature drops to the value that returns from the high-temperature release due to the temperature drop is opened). Control To.

Next, a time chart of each device by the control device 19 will be described with reference to FIG.

In FIG. 3, it is assumed that one indoor unit 2a is turned off from the ON state as shown in the chart (A), and the other indoor unit 2b continues the heating operation as it is as shown in the chart (B).

When the serial signal for stopping the indoor unit 2a on one side is input to the control device 19, the inverter device is set to the chart (E).
As shown in, from the frequency fHz that was driving until then −
The αHz operating frequency is lowered, and at the same time, the release valve 14 is closed to open as shown in the chart (G). At the same time, both the gas side two-way valve 13a and the liquid side two-way valve 12a of the indoor unit 2a are closed.

In this case, when the operating frequency fHz of the compressor 6 is between the Hi setting and the Lo setting, the outdoor fan 9 rotates at Lo (weak wind) as shown in the chart (F), and the indoor unit 2a on one side stops. Even if it is done, the Lo operation continues, but the fan 9 is turned off when the decreasing operating frequency value reaches the Lo setting.

When the operation is continued in this state, as shown in the chart (C), the stopped indoor unit 2a has a liquid, gas side two-way valve 12a,
Since 13a is closed, the refrigerant does not flow and the heat exchange temperature Tc decreases. On the other hand, all the refrigerant that has flowed to the two indoor heat exchangers will flow into the operating indoor unit 2b, and the heat exchange temperature Tc of the operating indoor unit 2b will rise. However, since the release valve 14 is opened as described above, the heat exchange temperature does not rise above the high temperature release point,
The outdoor fan 9 starts to fall below the peak temperature because it is in the OFF state, and when the temperature falls to the return point, the outdoor fan 9 turns on and the release valve 14 turns off, and the operating frequency is appropriately increased to match the air conditioning load of the indoor unit 2b. It is operated at the specified frequency.

As described above, since the release valve is opened immediately when the number of operating vehicles decreases, the heat exchanger temperature does not rise extremely. Also, the reason why the release valve is closed after it is opened is when the temperature of the heat exchanger has dropped to the normal release return point, and the release valve is closed after the high pressure of the refrigeration cycle has surely dropped. The heat exchanger temperature does not rise up to the high temperature release when the number of units decreases, and the heat exchanger temperature during operation does not drop extremely and the feeling of heating is not impaired.

In Fig. 3, the outdoor fan 9 turns Lo when switching the operating number.
The case of operation has been described, but when the frequency is set to Hi or higher and the outdoor fan 9 is operated at Hi and the frequency is decreased by αHz,
If it is between the Hi setting and the Lo setting, it switches to Lo operation when it reaches below the Hi setting. In addition, the Lo setting is set to + αHz or slightly higher than the operating frequency of Min Hz in order to reduce the frequency by αHz.

FIG. 4 shows another time chart of the control device 19 in the present invention.

In this example, as shown in the chart (E), when the operating frequency is operated at the Lo setting (Min Hz + α), the indoor unit 2a is turned off as shown in the chart (A). In this case, the outdoor fan 9 is in Lo operation,
It is turned off at the same time when the stop serial signal is input.
Further, when the operating frequency is kept at the Min Hz for a predetermined time, the frequency is increased, and when the frequency value reaches the Lo setting, the outdoor fan 9 is turned on as shown in the chart (E).
It may be turned on.

[Advantage of the Invention] As described above, according to the present invention, when the number of operating indoor units during the heating operation is reduced, the on-off valve which is stopped from the operation is closed and the release valve is opened. , Further lowering the operating frequency of the compressor by a predetermined value,
A control device that reduces or stops the air volume of the outdoor fan according to the decrease in the operating frequency, and then closes the release valve when the indoor heat exchanger temperature of the operating indoor unit drops below the second set value. Since the above is provided, it is possible to prevent an increase in the pressure of the heat exchanger in the indoor unit during operation, and at the same time, the temperature of the heat exchanger is not extremely lowered to impair the heating feeling.

[Brief description of drawings]

FIG. 1 is a refrigeration cycle diagram showing an embodiment of the present invention, and FIG.
FIG. 4 is a block diagram of a control device according to the present invention, FIG. 3 is a time chart diagram of the control device according to the present invention, FIG. 4 is a time chart diagram showing another example of FIG. 3, and FIG. It is a figure. In the figure, 1 is an outdoor unit, 2a and 2b are indoor units, 6 is a variable capacity compressor, 9 is an outdoor fan, 14 is a release valve,
Reference numeral 19 is a control device.

Claims (1)

[Scope of utility model registration request] 1. An outdoor unit for accommodating a variable capacity compressor, an outdoor fan, and an outdoor heat exchanger, the capacity of which is variable by changing an operating frequency, and a plurality of indoor units each accommodating an indoor heat exchanger. A release valve that includes a unit and a plurality of on-off valves that control the supply of refrigerant from the outdoor unit to each indoor unit for each indoor unit, and that returns the refrigerant discharged from the variable capacity compressor to the suction side. Is provided, and when the indoor heat exchanger temperature of the operating indoor unit exceeds the first set value, the release valve is opened, and then the indoor heat exchanger temperature is lower than the first set value. In a release control device for an air conditioner that closes the release valve when the value drops below a second set value, when the number of operating indoor units during heating operation decreases,
The open / close valve corresponding to the indoor unit that is stopped from operation is closed and the release valve is opened, and the operating frequency of the compressor is further reduced by a predetermined value, and the air volume of the outdoor fan is reduced according to the operating frequency reduction. A control device is provided that causes the release valve that has been lowered or stopped and that has been operated to open when the number of operating vehicles decreases, to close when the temperature of the indoor heat exchanger of the operating indoor unit drops below the second set value. The release control device of the air conditioner that features.