JP2508860B2 - Operation control device for air conditioner - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an operation control device for an air conditioner provided with a use-side expansion valve whose opening can be adjusted, and more particularly to a startup measure when cooling is low outside air. It is a thing.

(Prior Art) Conventionally, for example, an actual air conditioner has been disclosed in Japanese Utility Model Laid-Open No. 54-1675.
As disclosed in Japanese Patent No. 41, a compressor whose operating capacity can be adjusted in two stages of full load and unload by an unloader mechanism, an outdoor heat exchanger provided with an outdoor fan, an outdoor expansion valve, There is one in which an indoor expansion valve and an indoor heat exchanger are connected in order. Then, during the cooling operation, it is divided into three steps based on the temperature difference between the indoor temperature and the set temperature, the operating capacity of the compressor is adjusted according to the air conditioning state of the room, and the capacity adjustment for the cooling load is performed, It is designed to exert a predetermined cooling effect.

(Problems to be Solved by the Invention) In the above-described air conditioner, cooling may be performed throughout the year like air conditioning in a computer room, and cooling operation may be performed even in low outside air such as in winter. At this low outside air, when the cooling operation is started, the operating capacity of the compressor is set to the unload state, but since the indoor motor-operated valve is set to be controlled by superheat, the initial opening degree at startup is set. However, there was a problem that the low pressure (the pressure on the suction side of the compressor) was reduced. In particular, since the outdoor fan operates, the high pressure (condensation pressure) decreases, the pressure difference between high and low decreases, the circulation amount of the refrigerant decreases, the low pressure decreases, low pressure cut occurs, and the cooling operation stops. there were.

The present invention has been made in view of the above points, and an object thereof is to make it possible to smoothly start the cooling operation even when the outside air is low.

(Means for Solving the Problems) In order to achieve the above-mentioned object, means taken by the present invention are
Set the initial opening of the usage-side expansion valve larger than the superheat control opening, and in addition to this, decrease the fan air volume of the heat source-side heat exchanger, while opening all the usage-side expansion valves only at startup. It was done.

Specifically, as shown in FIG. 1 (a), claim (1)
The means taken by the invention according to claim 1 is such that a compressor (1) with a variable capacity, a heat source side heat exchanger (4), a use side expansion valve (7) with adjustable opening, and a use side heat exchanger. It is premised on an air conditioner in which a exchanger (8) is sequentially connected.

Then, the capacity control means (51) for adjusting the capacity of the compressor (1) according to the air conditioning load, and the opening degree of the utilization side expansion valve (7) become constant according to the degree of superheat. The opening degree control means (53) for controlling in this way and the temperature detection means (Th1) for detecting the outside air temperature and outputting the temperature signal are provided. Further, when the temperature signal of the temperature detecting means (Th1) is received at the time of activation of the cooling operation and the outside air temperature is lowered to a predetermined temperature or less set in advance, the capacity control means (51) within a predetermined time from the time of activation. Instead of the control of (1), there is provided a starting capacity means (55) for outputting a capacity signal so as to forcibly drive the compressor (1) with a capacity lower than the capacity by the capacity control means (53). In addition, when the temperature signal of the temperature detecting means (Th1) is received at the time of activation of the cooling operation and the outside air temperature is lowered to a predetermined temperature or less set in advance, the opening control means ( 53)
In place of the above control, the use side expansion valve (7) is provided with a start opening means (56) for outputting an opening signal so that the use side expansion valve (7) is forcibly opened to a start opening larger by a predetermined opening than the heating degree control opening. It has a specific configuration.

Further, the means taken by the invention according to claim (2) is, in the invention according to claim (1), provided with an air volume control means (54) for adjusting the air volume of the fan (12), while starting the cooling operation. At times, when the temperature signal of the temperature detecting means (Th1) is received and the outside air temperature falls below a predetermined temperature set in advance, the air volume control means (5
In place of the control of 4), a configuration is provided in which the fan (12) is forcibly stopped or a start air volume means (57) that outputs an air volume signal so as to drive at a lower air volume than the control of the air volume control means (54) is provided. I am trying.

As shown in FIG. 1 (b), the means taken by the invention according to claim (3) is that the compressor (1), the heat source side heat exchanger (4), and the opening degree are adjustable. A plurality of use side expansion valves (7), (7), ... And a plurality of use side heat exchangers (8),
Assuming that the air conditioner is formed by connecting (8), ... to the use side expansion valves (7), (7), ... Of the use side heat exchangers (8), (8) ,. While the heat exchange operation is stopped, it is controlled to be fully closed, while the use side heat exchangers (8), (8),
During the heat exchange operation of the above-mentioned expansion valves (7) on the use side,
(7), Opening degree control means (53) for controlling the opening degree according to the superheating degree so that the superheating degree becomes constant, and the outside air temperature or the saturation temperature corresponding to the evaporation pressure is detected and a temperature signal is output. Temperature detecting means (Th1, P1) are provided. Then, when the cooling operation is started by at least one of the use side heat exchangers (8), the temperature signal of the temperature detecting means (Th1, P1) is received and the outside air temperature or the saturation temperature equivalent to the evaporation pressure is set to a predetermined value. If the temperature is lower than the temperature, whether or not the heat exchange operation is performed instead of the control of the opening degree control means (53) within a predetermined time from the start-up so that the refrigerant circulation amount becomes a predetermined amount. All user side heat exchangers (8),
(8), all use side expansion valves (7) corresponding to
The starting opening means (58) for outputting an opening signal for opening (7), ... To a predetermined starting opening larger than the control opening of the opening control means (53) is provided.

(Operation) In the invention according to claim (1) having the above structure, during the cooling operation, the capacity control means (51) adjusts the capacity of the compressor (1) in accordance with the cooling load, while the opening control means ( Five
3) superheats the use-side expansion valve (7) and controls the cooling operation.

At the start of this cooling operation, the temperature detection means (Th
When the outside air temperature detected by 1) is lower than a predetermined temperature set in advance, the starting capacity means (55) outputs a capacity signal and the starting opening means (56) outputs an opening.

Then, the compressor (1) is set to a low capacity, the use-side expansion valve (7) is set to an opening larger than the superheat control opening, and the cooling operation is started. As a result, a predetermined refrigerant circulation amount is secured even when the outside air temperature at startup is low, and the low pressure (the suction side pressure of the compressor (1)) is maintained at a predetermined value or higher, and the cooling operation is performed. Is done smoothly.

Further, in the invention according to claim (2), the air volume control means (54) controls the heat source side fan (12), and when the outside air temperature is lower than the predetermined temperature at the start of the cooling operation, the start air volume means. (57) outputs an air volume signal. Then, in addition to the startup control of the compressor (1) and the use side expansion valve (7), the air volume of the fan (12) is reduced, for example, stopped or controlled to a low air volume. As a result, the heat source side heat exchanger (4)
The amount of heat exchange is reduced so that the high pressure (condensing pressure) is maintained at a predetermined value, and the low pressure is more reliably maintained at a predetermined value.

Further, in the invention according to claim (3), the cooling operation of at least one of the use side heat exchangers (8), (8) has been performed since the cooling operation was stopped. That is, when the heat exchange operation is started, all the use-side expansion valves (7), (7), ... Are opened to a predetermined opening degree regardless of whether or not the heat exchange operation is performed at a low outside air temperature, For example, it is fully opened to secure a predetermined refrigerant circulation amount and keep the low pressure at a predetermined value.

(Effect of the invention) Therefore, according to the invention of claim (1), when the outside air temperature is low at the time of starting the cooling operation, the capacity of the compressor (1) is reduced and the use side expansion valve (7) is used. Since the opening degree of) is made large, a predetermined refrigerant circulation amount can be secured, so that the lowering of the low pressure can be prevented.
As a result, the low-pressure cut does not occur even when the outside air temperature is low, and the cooling operation can be started smoothly, so that comfortable cooling can be reliably performed.

Further, according to the invention of claim (2), when the outside air temperature is low, the fan (12) is stopped or the air volume is set to be low, so that the high pressure can be prevented from decreasing, and the high pressure can be reduced. Since it is possible to prevent a decrease in low pressure due to, it is possible to more reliably start the cooling operation and further improve comfort.

Further, according to the invention of claim (3), since the plurality of utilization side expansion valves (7), (7), ... Are all opened at the time of starting the cooling operation at the low outside air temperature, the refrigerant circulation amount is reduced. Since it can be reliably maintained at the predetermined value, it is possible to reliably prevent the low pressure from decreasing. In particular, even when the pipe length is long or only the use side heat exchanger (8) having a small capacity is operated, a predetermined refrigerant circulation amount can be reliably ensured, so that low pressure cut can be prevented, The smooth cooling operation can be surely started.

(Examples) Examples of the present invention will be described below with reference to FIGS. 2 to 6.

FIG. 2 shows a refrigerant piping system of an air conditioner according to an embodiment of the present invention, in which two indoor units (A) and (B) are connected in parallel to one outdoor unit (X). It is multi-type.

In the outdoor unit (X), (1) is a compressor,
(2) is a demister that collects oil in the discharged refrigerant, (3) is a four-way selector valve that switches as shown by the solid line in the drawing during cooling operation, and switches as shown by the broken line in the drawing during heating operation, and (4) shows an outdoor fan An outdoor heat exchanger that is a heat source side heat exchanger that is provided with (12) and functions as a condenser during cooling operation and as an evaporator during heating operation, and (4a) is the outdoor heat exchanger (4).
An auxiliary heat exchanger (5) is an outdoor electric expansion valve that adjusts the refrigerant flow rate during cooling operation and depressurizes the refrigerant during heating operation,
(6) is a receiver for storing the liquid refrigerant, and (9) is an accumulator for removing the liquid refrigerant in the sucked refrigerant.

In addition, the indoor units (A) and (B) have the same configuration, and both are electrically driven indoors as a use-side electric expansion valve that decompresses the refrigerant during cooling operation and adjusts the refrigerant flow rate during heating operation. Expansion valve (7) and indoor fan (13)
And an indoor heat exchanger (8) which is a utilization side heat exchanger that functions as an evaporator during cooling operation and as a condenser during heating operation.

And, each of the above devices (1) to (9) is a refrigerant pipe (10).
The main refrigerant circuit (11) is connected to allow the refrigerant to flow, and transfers heat (or cold heat) obtained by heat exchange with the outdoor air to give it to the indoor air. The outdoor fan (12) in the outdoor unit (X) is configured to be able to switch the air volume between a high air volume H and a low air volume L.

Further, although not shown, the compressor (1) is opposed to each other by 2
Scroll mechanism for discharging the drawn refrigerant at a high pressure by the relative revolution of the two scrolls, and an unloader mechanism having a bypass hole for bypassing a part of the discharged refrigerant in the middle of the fixed scroll of the scroll mechanism. Built in. Then, a high pressure supply passage (1) for supplying a high pressure from the discharge pipe (10a) to the back pressure side of the unloader piston of the unloader mechanism via the capillary tube (16).
An unloader passage (17) that connects 5) and a suction pipe (10b) in the middle of the high-pressure supply passage (15) via an on-off valve (18).
Is provided and when the on-off valve (18) is closed, high pressure is supplied to the unloader mechanism to make the operating capacity of the compressor (1) 100% full load, while the on-off valve (18) is opened. In this case, a low pressure is supplied to the unloader mechanism so that the operating capacity of the compressor (1) is unload which is 50% of the full load.

Further, many sensors are arranged in the air conditioner, (Thd) is arranged in the discharge pipe (10a), a discharge pipe sensor for detecting the discharge pipe temperature, and (Th1) is an outdoor heat exchanger ( An outside air temperature sensor, which is a temperature detecting means for detecting the intake air temperature To as the outside air temperature, is arranged at the air inlet of 4), and (Th2) is arranged on the liquid pipe side of the outdoor heat exchanger (4), The outdoor liquid pipe sensor for detecting the liquid pipe temperature of the heat exchanger (4), (Th3) is arranged at the air suction port of the indoor heat exchanger (8), and is the room temperature for detecting the suction air temperature Ta as the indoor air temperature. Thermo, (Th4) is arranged in the liquid pipe of the indoor heat exchanger (8), the indoor liquid pipe sensor for detecting the liquid pipe temperature Te of the indoor heat exchanger (8), (Th5) is the indoor heat exchanger (8) ) Is an indoor gas pipe sensor for detecting the temperature of the gas pipe of the indoor heat exchanger (8).

Further, (Hps) is arranged in the discharge pipe (10a), a high pressure switch for stopping the compressor (1) when the high pressure rises excessively, (Lps) is arranged in the suction pipe (10b), and low pressure is A low pressure switch for stopping the compressor (1) when it drops excessively, (P1) is connected to the suction pipe (10b), and at the time of cooling operation, the low pressure of the refrigerant pressure (evaporation pressure equivalent saturation temperature Te), A pressure sensor that detects high pressure (condensation pressure equivalent saturation temperature Tc) during heating operation, (Ps) is arranged in the discharge pipe (10a), and the discharge pressure reaches an excessive rise value at which the high pressure switch (Hps) operates. First, the open / close valve (18) is opened to maintain the compressor (1) in an unloading state, and the outdoor fan (12) is changed from a high air volume H to a low air volume L during the heating operation and from a low air volume L during the cooling operation. A pressure switch for switching to a high air volume H, in which each of the above sensors is a controller. Is connected to (50), operation of the air conditioner in accordance with the signals of the sensors are adapted to be controlled.

In the figure, (19) connects the demister (2) and the suction pipe (10b) of the compressor (1) through a capillary (20), and an oil return pipe for returning oil, ( Reference numeral 21) is a shutoff valve provided in a communication pipe between the outdoor unit (A) and the indoor side.

The controller (50) includes a capacity control means (51) for the compressor (1), a first opening control means (52) for the outdoor electric expansion valve (5), and a first opening control means for the indoor electric expansion valve (7). The 2 opening degree control means (53) and the air volume control means (54) of the outdoor fan (12) are comprised. Then, the capacity control means (51) opens and closes the opening / closing valve (18) based on the air-conditioning load according to the room temperature detected by the room temperature thermostat (Th3) to change the capacity of the compressor (1) between full load and unload. Is configured to control. The first opening degree control means (52) controls the degree of superheat of the outdoor electric expansion valve (5) by the temperature detected by the outdoor liquid pipe sensor (Th2) and the pressure sensor (P1) during the heating operation.

On the other hand, the second opening degree control means determines the temperature detected by the indoor liquid pipe sensor (Th4) and the indoor gas pipe sensor (Th5) during the cooling operation, that is, during the heat exchange operation of the indoor heat exchangers (8) and (8). The indoor electric expansion valve (7) for each indoor unit (A), (B) is controlled so that the superheat degree becomes constant according to the superheat degree, and the operation of each indoor unit (A), (B) At the time of stop and thermo-off, that is, the indoor heat exchanger (8),
When the heat exchange operation of (8) is stopped, the indoor unit (A),
The indoor electric expansion valves (7) and (7) of (B) are controlled to be fully closed. The air volume control means (54) is an outside air temperature sensor (Th
The air volume of the outdoor fan (12) is controlled by the temperature detected in 1).

Further, the controller (50) includes a startup capacity means (55), a startup opening means (56), and a startup air volume means (57), each of which operates when the outside air temperature is low during cooling operation. ), The indoor electric expansion valve (7) and the outdoor fan (12) are controlled. The starting capacity means (55) is configured to output a capacity signal when the outside air temperature is 24 ° C. or lower and forcibly drive the compressor (1) by unloading (low capacity) for 30 seconds after starting. ing. The starting opening means (56) outputs an opening signal so that the opening is larger than the superheat control opening. When the outside air temperature is 18 ° C or lower, When it is higher, the second starting opening is forcibly held for 30 seconds after the starting.

Further, the startup air volume means (57) outputs an air volume signal, and when the outside air temperature is 6 ° C. or less, the outdoor fan (12) stops,
When the temperature is 13 ° C. or less, the air volume L is low, and when the temperature is higher than 13 ° C., the air volume H is high.

Next, the cooling operation of the air conditioner will be described.

First, the refrigerant discharged from the compressor (1) is condensed in the outdoor heat exchanger (4), divided into the indoor units (A) and (B), and decompressed by the indoor electric expansion valves (7) and (7). Then, after being evaporated in the indoor heat exchangers (8) and (8), they merge and return to the compressor (1).

During this cooling operation, the capacity of the compressor (1) is changed to full load or unload by the capacity control means (51) opening and closing the opening / closing valve (18) based on the room temperature detected by the room temperature thermostat (Th3). Controlled. The opening degree of the indoor electric expansion valve (7) is controlled based on the temperatures detected by the indoor liquid pipe sensor (Th4) and the indoor gas pipe sensor (Th5).
While the superheat degree is controlled by 3) (superheat degree 5 ° C), the air volume of the outdoor fan (12) is low by the air volume control means (54) based on the outside air temperature detected by the outside air temperature sensor (Th1).
Or, it is controlled to a high air volume.

Next, the startup control during the cooling operation will be described based on the control state diagram of FIG. 3 and the control flow diagrams of FIGS. 4 to 6.

The outdoor electric expansion valve (5) in the main refrigerant circuit (11) is set to a fully open state (especially when the outside air is low).

Therefore, first, in the compressor (1), it is determined whether or not the cooling operation is started in step ST1, and if it is set to the heating operation, the process proceeds to step ST2, the normal heating operation control is performed, and the process returns. On the other hand, if the cooling operation is set, the process proceeds from step ST1 to step ST3, and it is determined whether the operation is in progress. Then, when not in operation, that is, when the operation switch is not turned on, the process proceeds to step ST4 and returns as a normal stop state, while when the operation switch is turned on and is in operation,
The process moves from step ST3 to step ST5, and it is determined whether the timer TM1 is counting.

In this step ST5, if the timer TM1 has stopped counting, the process proceeds to step ST6, it is determined whether or not it is activated, and if the operation switch is turned on, it is determined to be active and the process proceeds to step ST7, and the timer TM1 (30 second timer) is set, and the process proceeds to step ST8, and it is determined whether the outside air temperature To is 20 ° C. or higher. If the outside air temperature To is lower than 20 ° C, the process proceeds from step ST8 to step ST9 to start the compressor (1) with a low unload capacity, while if the outside air temperature To is higher than 20 ° C. The process moves from step ST8 to step ST10, and the compressor (1) is set to a capacity corresponding to the indoor load, for example, the indoor temperature, and is started by unloading or full loading. That is, when the outside air temperature To is 20 ° C. or less (see P1 in FIG. 3), the starting capacity means (55) outputs a capacity signal, opens the on-off valve (18), and forcibly shuts down the compressor (1). When the outdoor temperature To is higher than 20 ℃ while starting with a low load capacity and returning, the on-off valve (18) is opened and closed based on the detected temperature of the indoor thermostat (Th3), and the compressor (1) is unloaded. Or start with full load and return.

After that, the operation from step ST1 is repeated, and since the timer TM1 has started counting in step ST5 (see step ST7), the steps ST6 and ST7 are skipped and the process goes to step ST8 to repeat the above operation. Become. That is, when the outside air temperature To is 20 ° C. or less, the compressor (1) is started by unloading regardless of the indoor load, and the compressor (1) is driven by this unloading for 30 seconds.

After that, when the timer TM1 set in the above step ST7 times out, the operation moves from step ST5 to step ST6, and since it is currently being driven, the operation proceeds from step ST6 to step ST11 to perform normal cooling operation, and the compressor ( 1)
Capacity is controlled by the indoor load.

Further, as indicated by points P1 and P2 in FIG. 3, the capacity of the compressor (1) at startup may be set in consideration of the outside air temperature To at the time of operation stop before startup. That is, when the outside air temperature To is 20 ° C. or less at the time of operation stop and the outside air temperature To is 24 ° C. or less at start-up, the compressor (1) is forcibly started by unloading, and the If the outside air temperature To is higher than 20 ° C, the outside air temperature at startup will be as shown in the flow above.
The capacity of the compressor (1) is set by To.

Next, the control of the indoor electric expansion valve (7) will be described based on FIG. 5, and in steps ST21 to ST27, it is the same as steps ST1 to ST7 in the flow of the compressor (1), and the heating operation is set. Then, the process proceeds from step ST21 to step ST22, and the normal heating control is performed. When the cooling operation is stopped, the process proceeds from step ST23 to step ST24 and the fully closed state is controlled. Then, when the cooling operation starts,
The determination in step ST25 is NO because the timer TM1 is not currently set, and the determination in step ST26 is YES because the timer is currently activated, and the timer TM1 is set in step ST27.

Then, the process proceeds to step ST28, it is determined whether the outside air temperature To is 15 ° C. or higher, and if the outside air temperature To is lower than 15 ° C., the process proceeds from step ST28 to step ST29 and the initial opening AT is expressed by the following equation. Set to 1 opening and return.

AT = 40 × (Ta + 30)… Ta: Indoor temperature (indoor thermo (Th3) detection temperature) On the other hand, if the outside air temperature To is higher than 15 ° C, step ST28
From step ST30 to the second opening which shows the initial opening AT in the following equation
Set to the opening degree and return.

AT = 40 × Ta… In other words, when the outside air temperature To is lower than 15 ° C (see E1 in Fig. 3), the starting opening means (56) outputs an opening signal to superheat the indoor electric expansion valve (7). When the outside air temperature To is 15 ° C or higher, the indoor electric expansion valve (7) is set to the initial opening AT of the formula to set the initial opening AT of the formula larger than the control opening to To increase.

After that, the operation from step ST21 is performed, and thereafter steps ST26 and ST27 are skipped to perform the above-mentioned operation, and the indoor electric expansion valve (7) is forcibly forced to have a predetermined initial opening degree until 30 seconds have elapsed from the time of startup. Set to AT.

When the timer TM1 times out after the lapse of 30 seconds, the process proceeds from step ST26 to step ST31, and the indoor electric expansion valve (7) is subjected to normal superheat control (SH = 5 ° C.) and returns. .

In addition, as shown at points E1 and E2 in FIG. 3, when the outside air temperature To at the time of stop is 15 ° C. or less, the outside air temperature To at the time of operation stop is taken into consideration as in the control of the compressor (1). If the outside air temperature To at startup is 18 ° C or less, the indoor electric expansion valve (7)
Is set to the initial opening AT of the formula, and the outside air temperature To at stop is
When the temperature is higher than 15 ° C, the indoor electric expansion valve (7) may be controlled as in the above-mentioned flow.

Next, the control of the outdoor fan (12) will be described with reference to FIG. 6. Steps ST41 to ST47 are the same as steps ST1 to ST7 in the flow of the compressor (1), and the heating operation is set. Then, the routine proceeds from step ST41 to step ST42, and the normal heating operation control is performed. When the cooling operation is stopped, the routine proceeds from step ST43 to step ST44, and the outdoor fan (12) is stopped and controlled. Then, when the cooling operation starts, the determination in step ST45 is NO because the timer TM1 is not currently set, and the determination in step ST46 is YES because the timer is currently activated, and the timer TM1 is set in step ST47.

Then, the process proceeds to step ST48, where it is determined whether the outside air temperature To is lower than 11 ° C (see F1 in Fig. 3). If it is lower than 11 ° C, the process proceeds to step ST49 to determine whether the outside air temperature To is lower than 4 ° C. It is determined whether or not (see F2 in FIG. 3). Therefore, outside temperature
If To is lower than 4 ° C, step ST49 to step ST
Move to 50, stop the outdoor fan (12) and return, while if the outside air temperature To is higher than 4 ° C, move from step ST49 to step ST51 and set the outdoor fan (12) to low air volume L and return. To do. Further, when the outside air temperature To is higher than 11 ° C., the process moves from step ST48 to step ST52, sets the outdoor fan (12) to a high air volume H, and returns.

That is, the start air volume means (57) outputs an air volume signal according to the outside air temperature To at startup, controls the outdoor fan (12) to stop when the outside air temperature To is lower than 4 ° C, and 4 ° C to 11 ° C.
Low air volume L between, and high air volume H above 11 ° C,
Control the amount of heat exchange.

After that, the operation from step ST41 is repeated, and thereafter,
The above-described operation is performed by skipping steps ST46 and ST47, and the outdoor fan (12) is set to a predetermined air volume until 30 seconds have elapsed from the time of startup.

Then, when the timer TM1 times out after the lapse of 30 seconds, the process proceeds from step ST46 to step ST53, and the outdoor fan (12) is subjected to normal cooling control and returns.

In addition, as shown in F1 to F4 of FIG. 3, the outside air temperature To is considered to be between 4 ° C. and 11 ° C. at the time of stop in consideration of the outside air temperature To when the operation is stopped as in the control of the compressor (1). 4 ℃ ~ 13 at startup
If the temperature is between 0 ° C (see F2 to F3 in Fig. 3), the air volume is low, and if it is 4 ° C or less at the time of stop and 6 ° C or less (see F4 in Fig. 3) at the time of start, it is 11 ° C or more at the time of stop. At this time, the high air volume H may be set as in the above flow.

As described above, when the cooling operation is started, the outside air temperature
When To is lower than a predetermined temperature, the capacity of the compressor (1) is unloaded, the outdoor electric expansion valve (5) is fully opened, and the indoor electric expansion valve (7) is opened at a temperature higher than the normal superheat control opening. The air flow rate of the outdoor fan (12) is widened to zero or low, a predetermined refrigerant circulation amount is secured, and the low pressure is maintained at a predetermined value.

On the other hand, during the heating operation, the four-way switching valve (3) is set to the second position.
Switching to the broken line in the figure, the refrigerant is circulated from the compressor (1) through the indoor heat exchanger (8) and the outdoor heat exchanger (4) in this order. Then, heating operation control of the compressor (1) and the like is performed (see step ST2 and the like).

Therefore, when the outside air temperature is low at the start of the cooling operation, the compressor (1) has a low capacity and the opening degree of the indoor electric expansion valve (7) is increased, so that a predetermined refrigerant circulation amount is obtained. Therefore, it is possible to prevent the low pressure from decreasing. As a result, the low-pressure cut does not occur even when the outside air temperature is low, and the cooling operation can be started smoothly, so that comfortable cooling can be reliably performed.

Further, when the outside air temperature is low, the outdoor fan (12) is stopped or the air volume is set to be low, so that the high pressure can be prevented from decreasing, and the low pressure can be prevented from decreasing due to the high pressure decreasing. Therefore, the cooling operation can be started more reliably, and the comfort can be further improved.

Although the present embodiment has been described with respect to the multi-type air conditioner, the present invention is not limited to this, and may be a cooling-only machine.

Further, the number of capacity stages of the compressor is not limited to two, and may be controlled to three or more stages, the number of control stages of the outdoor fan (12) is not limited to that in the embodiment, and a medium air volume or the like may be provided. The initial opening AT of the indoor electric expansion valve (7) is not limited to the embodiment, and may be larger than the superheat control opening.

FIG. 7 is a control flow showing another embodiment of the startup control during the cooling operation. In this embodiment, a plurality of indoor units, for example, two indoor units (A), as shown in FIG. The target is an air conditioner equipped with (B). Then, instead of the starting capacity means (55) and the starting opening means (56) in the previous embodiment, one indoor unit (A) or (B) starts the cooling operation and the indoor heat exchanger (8). At the time of startup when heat exchange is performed by the other indoor unit (B) or (A), even if the cooling operation is stopped or thermo-off, all indoor electric expansion valves (8) and (8) are fully opened for a predetermined time from the time of startup. The controller (50) is configured with a starting opening means (58) for controlling.

Therefore, the activation control operation will be described with reference to FIG.

First, when the control operation is started, it is determined in step ST61 whether or not the outdoor temperature detected by the outdoor air temperature sensor (Th1) is lower than 5 ° C. If the outdoor temperature is 5 ° C or higher, the process proceeds to step ST62. It is determined whether or not the indoor units (A) and (B) are thermo-ON based on the detected temperature of the room temperature thermo (Th3). Then, when the indoor units (A) and (B) are turned on during the cooling operation in which the outdoor temperature is high, the process proceeds from step ST62 to step ST63, and the second opening means (53) causes the indoor electric expansion valves (7), (7). ) Is controlled by the degree of superheat and returns while the thermostat is turned off, the step
The process moves from ST62 to step ST64, and the second opening means (53) controls the indoor electric expansion valves (7) and (7) to be fully closed and returns. When this operation is performed during the normal cooling operation, and the cooling operation is stopped, the second opening means (53) fully operates the indoor electric expansion valves (7), (7) for each indoor unit (A), (B). Control to close.

On the other hand, in step ST61, if the outside air temperature is lower than 5 ° C, the determination becomes YES, the process proceeds to step ST65, it is determined whether or not the compressor (1) is driven, and if it is driven, In ST65, it is determined whether or not the compressor (1) is currently started from the stopped state. If it is immediately after the start, the process proceeds to step ST67 and the timer is set. That is, when one or both of the indoor units (A) and (B) are cooled in the low outside air temperature state, the compressor (1) starts and the timer starts.

After that, the process moves from step ST67 to step ST68, and it is determined whether or not the timer has timed out. Until timed up, the process moves to step ST69 to control all indoor electric expansion valves (7) and (7) to fully open. To return. Then, the operations of steps ST61 and ST65 to ST69 described above will be repeated, and at this time, the determination in step ST66 is NO because it is not immediately after the start, so step ST67 is skipped and the process moves to step ST68, and the timer times out. Until then, all indoor electric expansion valves (7), (7) are fully opened. That is, when one of the indoor units (A) and (B) has stopped the cooling operation or is in the thermo-off state,
That is, when the indoor heat exchanger (8) of the indoor unit (A) or (B) does not perform heat exchange, the indoor electric expansion valve (7) of the indoor unit (A) or (B) that does not perform heat exchange. ) Is normally controlled to be fully closed, but the indoor unit (A) or (B) that starts the cooling operation when the low outside air temperature is activated.
The indoor electrically driven expansion valve (7), all the indoor electrically operated valves (7) in all the indoor units (A), (B),
Fully open (7).

After that, when the above timer expires, step
Move from ST68 to step ST70, where each indoor unit (A),
Whether or not (B) is in the thermo-on state is determined, and in the case of the thermo-on indoor unit (A) or (B), step ST
Moving to 71, the indoor motor-operated valve (7) is normally controlled (superheat control) and returns, while the indoor unit (A) or (B) with the thermostat off is stepped from step ST70.
Move to ST64 and control the indoor electric valve (7) to be fully closed. Further, also in the indoor unit (A) or (B) in which the cooling operation is stopped, the indoor electric expansion valve (7) is returned from fully open to fully closed.

Further, in step ST65, if the compressor (1) is stopped, the determination becomes NO, the process proceeds to step ST64, and the indoor electric expansion valves (7) and (7) are controlled to be fully closed.

Other configurations and operations are the same as in the previous embodiment.

Therefore, since the both indoor electric expansion valves (7) and (7) are all opened at the time of starting the cooling operation at the low outside air temperature, the refrigerant circulation amount can be reliably maintained at the predetermined value, so that the low pressure It is possible to reliably prevent the decrease.
Especially when the pipe length is long, for example, the outdoor unit (X)
And the distance between the indoor units (A) and (B) is 100m,
Even when only the indoor unit (A) or (B) having a small capacity is operated, the predetermined refrigerant circulation amount can be reliably ensured, so that the low pressure cut can be prevented and the smooth cooling operation can be started. It can be done reliably.

Incidentally, in the embodiment of FIG. 7, it is not necessary to control the capacity of the compressor (1) at the time of start-up unlike the previous embodiment. In addition, the outdoor fan (12) may be startup-controlled as in the previous embodiment.

Further, the opening degree of the indoor electric expansion valve (7) is not limited to the full opening (see step ST69 in FIG. 7) and may be any one that can secure a predetermined refrigerant circulation amount.

Furthermore, the temperature detecting means may use a pressure sensor (P1) instead of the outside air temperature sensor, and when the evaporation pressure equivalent saturation temperature Te by the pressure sensor (P1) becomes a predetermined temperature or lower, the temperature at start-up is low outside air temperature. Therefore, the indoor electric expansion valve (7) may be controlled to be fully opened.

[Brief description of drawings]

1 (a) and 1 (b) are block diagrams showing the configuration of the present invention. 2 to 7 show an embodiment of the present invention, FIG. 2 is a refrigerant system diagram, FIG. 3 is a state characteristic diagram of a compressor, an indoor electric expansion valve, and an outdoor fan with respect to outdoor temperature, and FIG. FIG. 5 is a control flow chart of the compressor, FIG. 5 is a control flow chart of the indoor electric expansion valve, and FIG. 6 is a control flow chart of the outdoor fan. FIG. 7 is a control flow chart of an indoor electric expansion valve showing another embodiment. (1) ... Compressor (4) ... Outdoor heat exchanger (7) ... Indoor electric expansion valve (8) ... Indoor heat exchanger (12) ... Outdoor fan (Th1) ... Outdoor air temperature sensor (P1) ... Pressure sensor ( 50) ... Controller (51) ... Capacity control means (53) ... Second opening control means (54) ... Air volume control means (55) ... Starting capacity means (56), (58) ... Starting opening means (57) ... Starting air volume means

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location F25B 1/00 341 F25B 1/00 341R 351 351K 351T (56) Reference JP-A-62-10486 ( JP, A) JP-A-3-137460 (JP, A) JP-A-57-198942 (JP, A) JP-A-63-290368 (JP, A) Actually developed 59-62469 (JP, U)

Claims (3)

(57) [Claims] 1. A compressor (1) having a variable capacity, a heat source side heat exchanger (4), and a use side expansion valve (7) with adjustable opening.
And a utilization side heat exchanger (8) are connected in sequence, a capacity control means (51) for adjusting the capacity of the compressor (1) according to an air conditioning load, and the utilization side expansion. Opening degree control means (53) for controlling the opening degree of the valve (7) according to the superheating degree so that the superheating degree becomes constant, and temperature detection means (Th1) for detecting the outside air temperature and outputting a temperature signal. When the temperature signal of the temperature detecting means (Th1) is received at the time of activation of the cooling operation and the outside air temperature has dropped below a predetermined temperature set in advance, the capacity control means (53) within a predetermined time from the time of activation. In place of the control of (1), starting capacity means (55) for outputting a capacity signal to forcibly drive the compressor (1) with a capacity lower than the capacity by the capacity control means (53), and the start of the cooling operation. Sometimes the temperature signal from the temperature detection means (Th1) is received and the outside air temperature is set in advance. When the temperature falls below the predetermined temperature, the use-side expansion valve (7) is forcedly set to a predetermined value from the superheat control opening instead of the control of the opening control means (53) within a predetermined time from the start. An operation control device for an air conditioner, comprising: an opening degree means (56) for outputting an opening degree signal so as to open to a large opening degree. 2. A heat source side heat exchanger (4) having a variable capacity compressor (1), a variable air volume fan (12), and a use side expansion valve (7) with adjustable opening. And a utilization side heat exchanger (8) are connected in sequence, a capacity control means (51) for adjusting the capacity of the compressor (1) according to an air conditioning load, and the utilization side expansion. Opening degree control means (53) for controlling the opening degree of the valve (7) so that the superheating degree becomes constant according to the superheating degree, and air volume control means (54) for adjusting the air volume of the fan (12).
A temperature detecting means (Th1) for detecting the outside air temperature and outputting a temperature signal, and an outside air temperature falling below a preset predetermined temperature upon receiving the temperature signal of the temperature detecting means (Th1) when the cooling operation is started. If it has decreased, instead of the control of the capacity control means (51) within a predetermined time from the time of startup, the compressor (1) is forcibly driven with a capacity lower than the capacity by the capacity control means (53). As described above, when the starting capacity means (55) for outputting the capacity signal and the temperature signal of the temperature detecting means (Th1) at the time of starting the cooling operation are received and the outside air temperature is lowered to a predetermined temperature or lower, Instead of controlling the opening control means (53) within a predetermined time from the time of startup, the use-side expansion valve (7) is forcibly opened to a startup opening that is a predetermined opening larger than the superheat control opening. Degree opening means for outputting degree signal (56)
When the temperature signal of the temperature detecting means (Th1) is received at the time of starting the cooling operation and the outside air temperature is lower than a predetermined temperature set in advance, the air volume control means (54) within a predetermined time after the start. In place of the above control, the fan (12) is forcedly stopped or a start air volume means (57) for outputting an air volume signal to drive the fan at a lower air volume than the control of the air volume control means (54) is provided. A characteristic control device for an air conditioner. 3. A compressor (1) and a heat source side heat exchanger (4)
And a plurality of use-side expansion valves (7) whose opening can be adjusted,
(7), ... and a plurality of utilization side heat exchangers (8), (8),
In the air-conditioning apparatus in which the above-mentioned use-side expansion valves (7), (7), ... Are connected to the use-side heat exchangers (8), (8) ,. While being controlled to be fully closed, during the heat exchange operation of the use side heat exchangers (8), (8), ..., The use side expansion valves (7), (7) ,.
An opening degree control means (53) for controlling the opening degree of the air conditioner so that the degree of superheat becomes constant according to the degree of superheat, and a temperature detection means for detecting the outside air temperature or the saturation temperature equivalent to the evaporation pressure and outputting a temperature signal ( Th1, P1) and at least one of the use side heat exchangers (8) at the time of starting the cooling operation, the temperature signal of the temperature detecting means (Th1, P1) is received and the outside air temperature or the vapor pressure equivalent saturation temperature is received in advance. When the temperature is lower than the set predetermined temperature, the heat exchange operation is performed instead of the control of the opening degree control means (53) within a predetermined time from the start-up so that the refrigerant circulation amount becomes the predetermined amount. All heat exchangers on the use side (8), whether or not
(8), all use side expansion valves (7) corresponding to
And (7) are provided with starting opening means (58) for outputting an opening signal for opening a predetermined opening larger than the control opening of the opening control means (53). The air conditioner operation control device.