WO2011037012A1 - Air conditioner - Google Patents

Abstract

An air conditioner is provided with: an indoor unit which is provided with an indoor heat exchanger and an indoor fan; an outdoor unit which is connected with the indoor unit and provided with a compressor comprising a plurality of cylinders, the number of operated cylinders being variable, an outdoor heat exchanger, and a throttle mechanism; and a control unit which performs variable control of the operation speed of the compressor. The control unit is capable of operating, in cooling operation, the air conditioner in an operation mode which sets the number of operated cylinders in the compressor to be the minimum number of cylinders on the basis of an outside air temperature and sets the operation speed of the compressor to be the minimum speed at which refrigeration cycle operation is possible. The air conditioner adopts the compressor capable of variable control of the number of operated cylinders and the operation speed, thereby being capable of operation while a refrigerant discharge quantity is reduced during minimum-performance operation in the cooling operation. This degrades the performance of the whole refrigeration cycle to prevent a blow-out temperature from the indoor unit from being cooled excessively, enabling comfortable air-conditioning operation.

Description

Air conditioner

The present invention relates to an air conditioner equipped with a compressor.

Generally, when installing an air conditioner, an air conditioner having an operating capability that matches the volume of the installation location is installed. An air conditioner in recent years is equipped with an inverter, and the operating capacity of the air conditioner is controlled by changing the rotation speed of the compressor by the inverter. For this reason, it can adapt to an installation place or can perform the optimal driving | operation according to a user's hope.

However, in cooling operation at low load, the compressor is stopped when the room temperature falls and the air conditioning load condition falls below the minimum capacity, and the operation is restarted when the room temperature rises again. It was. In many cases, the intermittent temperature tends to increase the fluctuation of the room temperature, and the user's comfort is never increased.

Also, in an air conditioner installed in a relatively large room, the capacity of the compressor is large, so the minimum capacity cannot be reduced much. Therefore, in intermittent operation, when the compressor is ON, a fairly cold air blows out, so there is a problem in comfort such that the user feels cold when directly hitting this air, or cold air stays on the floor and the feet cool down. Arise.

In the air conditioner disclosed in Patent Document 1 below, in order to prevent such a problem, two indoor throttle mechanisms [indoorinthrottle mechanism] provided in the middle of the two heat exchangers in the indoor unit are used. A dehumidifying operation mode is provided in which the heat exchanger functions as an evaporator and a reheater. According to this air conditioner, the minimum capacity operation can be performed without stopping the compressor, that is, without performing the intermittent operation, and the above-described problems can be prevented.

Japanese Unexamined Patent Publication No. 2006-162197

In the air conditioner disclosed in Patent Document 1, when it is determined that the air conditioning load condition is lower than the minimum capacity of the compressor during the normal cooling operation, the indoor throttle mechanism is set to the minimum flow rate. Transition. This is a change to the dehumidifying operation mode described above by changing the indoor throttle mechanism. The compressor is operated at a low capacity, but the dehumidifying operation is performed not by the compressor control but by the heat exchanger control in the indoor unit. It has been broken.

That is, the amount of refrigerant discharged from the compressor cannot be changed greatly. For this reason, since the amount of circulating refrigerant in the refrigeration cycle does not change greatly, the heat exchange capacity in the indoor heat exchanger cannot be significantly reduced. This is the same during the dehumidifying operation. When the indoor throttle mechanism is set to the minimum flow rate under the air conditioning load condition that is lower than the minimum capacity of the compressor, the evaporation temperature becomes low and the air temperature blown into the room is low. .

In this state, cold air stays under your feet even if you set a low wind and perform continuous operation. In addition, the user's entire body cools down at bedtime.

Accordingly, it is an object of the present invention to provide an air conditioner that can be comfortably air-conditioned by preventing overcooling by operating control that does not overcool the air temperature during cooling.

The present embodiment includes an indoor heat exchanger, an indoor unit provided with an indoor fan, a compressor connected to the indoor unit and having a plurality of cylinders, the number of operating cylinders being variable, and outdoor heat exchange. And an outdoor unit provided with a throttle mechanism, and a control unit that variably controls the operating rotational speed of the compressor, and the control unit operates the compressor based on the outside air temperature during cooling operation. An air conditioner capable of operating the air conditioner in an operation mode in which the number of cylinders is set to a minimum number of cylinders and the operation speed of the compressor is set to a minimum number of rotations capable of refrigeration cycle operation. provide.

According to the air conditioner, by adopting a compressor in which the number of operating cylinders and the number of operating revolutions are variably controlled, the capacity of the entire refrigeration cycle is reduced by performing an operation in which the refrigerant discharge amount is reduced during the minimum capacity operation during the cooling operation. It can be lowered to prevent the air blown from the indoor unit from being too cold, and comfortable air conditioning becomes possible.

It is a whole view showing the whole air conditioner composition in an embodiment. It is a circuit diagram which shows the structure of the refrigerating cycle containing the said air conditioner. It is a block diagram which shows the internal structure of the control unit of the said air conditioner. It is explanatory drawing which shows the driving | running state (2 cylinder operation) of the compressor of the said air conditioner. It is explanatory drawing which shows the driving | running state (1 cylinder operation) of the said compressor. It is a flowchart of control of the air conditioner. It is a graph which shows the measurement result of various data after the cool wind operation mode [cool | breeze operation mode] of the said air conditioner is started.

Hereinafter, embodiments will be described in detail with reference to the drawings.

As shown in FIG. 1, the air conditioner 1 includes an indoor unit 2 installed indoors, an outdoor unit 3 connected to the indoor unit 2, and a remote controller 4. The user basically performs various operations such as operation mode selection, temperature setting, and air volume setting of the air conditioner 1 using the remote controller 4.

The indoor unit 2 includes a moving panel 2b that can be separated from the front panel 2a. When the movable panel 2b is separated from the front panel 2a, a space is generated between the front panel 2a and the movable panel 2b, and indoor air is sucked through the space (air inlet). An air inlet 2 c is also provided on the upper surface of the indoor unit 2. An air outlet 2d is provided at the lower part of the front panel 2a. The outlet 2d is also provided with a vertical air flow louver 2e for adjusting the blowing air up and down and a horizontal air flow louver 2f for adjusting the blowing air left and right. It has been.

The indoor unit 2 accommodates an indoor heat exchanger and an indoor fan (not shown) in a suction port of the front panel 2a and a ventilation path from the suction port 2c to the air outlet 2d.

The movable panel 2b is movable in a direction away from the front panel 2a, and the inner suction port is opened by the movement. Further, the movable panel 2b closes the inner suction port by moving (returning) in a direction in contact with the front panel 2a.

In this embodiment, the indoor unit 2 as shown in FIG. 1 is used, but other types of indoor units (for example, ceiling-mounted-built-in type indoor units) are used. May be.

The outdoor unit 3 is installed outside and supplies refrigerant to the indoor unit 2 connected by the refrigeration cycle A (see FIG. 2). Although the outdoor unit 3 is shown in a simplified manner in FIG. 1, as will be described later, the outdoor unit 3 includes a compressor 31 and the like inside.

The remote controller 4 is used to transmit an instruction such as an operation mode selected by the user to the indoor unit 2. As shown in FIG. 1, the remote controller 4 in the present embodiment is provided with a display unit 4a representing various displays and an operation mode button 4b for setting an operation mode of “cooling” or “heating”.

Although not shown in the remote controller 4 in FIG. 1, other buttons such as a temperature setting button are also provided. The shape, design, etc. of the remote controller 4 are merely examples, and the shape, design, etc. are not limited. Furthermore, transmission / reception of signals between the remote controller 4 and the indoor unit 2 can be performed by various communication formats in addition to the wireless communication format as shown in FIG. 1 or FIG. 3.

As described above, the air conditioner 1 includes the indoor unit 2 and the outdoor unit 3 connected to the indoor unit 2. As shown in FIG. 2, the indoor unit 2 includes an indoor heat exchanger 21 that performs heat exchange between the refrigerant and room air, and an indoor fan 22 that blows the heat-exchanged air into the room. Is provided.

Although only the indoor heat exchanger 21 and the indoor fan 22 are shown in the indoor unit 2 in FIG. 2, each device normally provided in an indoor unit of an air conditioner is naturally provided. An indoor heat exchanger 21, an indoor fan 22, and a control unit 23 for controlling each device (not shown) are further provided. In the indoor unit 2 of FIG. 2, transmission / reception of signals of the control unit 23 is shown in a simplified manner.

In the outdoor unit 3, a compressor 31, a four-way valve 32, an outdoor heat exchanger 33, a throttling mechanism 34, an accumulator 35, and a switching valve 36 that switches a refrigerant supplied to the compressor 31 are connected via a pipe. It is connected. The indoor unit 2 and the outdoor unit 3 are connected by a refrigerant circulation pipe, and a refrigeration cycle A is configured. That is, the piping is connected between the throttle mechanism 34 of the outdoor unit 3 and the four-way valve 32 so that the indoor heat exchanger 21 of the indoor unit 2 is located. The refrigerant flows in the order of the throttle mechanism 34, the indoor heat exchanger 21, and the four-way valve 32 (during cooling), or in the order of the four-way valve 32, the indoor heat exchanger 21, and the throttle mechanism 34 (during heating).

In the present embodiment, a pulse motor valve (PMV) is used as the throttle mechanism 34, and a four-way valve is used as the switching valve 36. Moreover, the control unit 37 which controls each apparatus which comprises the outdoor units 3, such as the compressor 31 mentioned above, the outdoor heat exchanger 33, and the switching valve 36, is further provided. In the outdoor unit 3 of FIG. 2, transmission / reception of signals of the control unit 33 is shown in a simplified manner.

The compressor 31 is a so-called dual compressor provided with a plurality of (two in this embodiment) cylinders as will be described later. The refrigerant is supplied to the compressor 31 via the accumulator 35. Further, the high-pressure refrigerant compressed in the compression chambers 31b and 31f, which will be described later, is discharged to the three-way valve 32 and the like through the internal space of the compressor 31 (the inside of the compressor 31 becomes discharge pressure).

A supply path for each of the two cylinders of the compressor 31 is provided on the discharge side of the accumulator 35 (see also FIGS. 4 and 5). The first supply path M that is one system directly supplies the refrigerant to the compressor 31. The refrigerant supplied via the first supply path M is a low-pressure refrigerant that has passed through the accumulator 35. The second supply path N that is the other system supplies the refrigerant to the compressor 31 via the switching valve 36. The refrigerant supplied via the second supply path N is the low-pressure refrigerant (FIG. 4: N1 + N2: O and Q) that has passed through the accumulator 35, or the high-pressure refrigerant supplied from the compressor 31 (FIG. 5: N2). : Any one of P and R).

Here, the operation of the air conditioner 1 will be described by taking the cooling operation as an example. In the cooling operation by the refrigeration cycle A, the refrigerant flows in the direction indicated by the solid line arrow in FIG. First, the refrigerant is compressed by the compressor 31 in the outdoor unit 3 and discharged as a high-temperature high-pressure gas. The high-temperature and high-pressure gaseous refrigerant is guided to the outdoor heat exchanger 33 through the four-way valve 32. The refrigerant is cooled by receiving wind from the outdoor fan 38 in the outdoor heat exchanger 33, and a part or all of the refrigerant is condensed. Furthermore, the refrigerant in the liquid phase state or the gas-liquid two-phase state is expanded by the throttle mechanism 34 and becomes a low pressure. The gas-liquid two-phase refrigerant that has exited the throttle mechanism 34 flows into the indoor heat exchanger 21 and exchanges heat with the indoor air. That is, the refrigerant evaporates by heat exchange, and the air sucked into the indoor heat exchanger 21 is cooled. The cooled air is supplied into the room by the indoor fan 22 and the room is cooled. The refrigerant after the heat exchange passes through the four-way valve 32 and returns to the compressor 31 via the accumulator 35. Thereafter, the above-described refrigeration cycle is repeated. On the other hand, in the heating operation, the refrigerant flows in the direction indicated by the broken-line arrow in FIG. 2, and the refrigerant is condensed in the indoor heat exchanger 21 to heat the room.

FIG. 3 is a block diagram showing the internal configuration of the control unit 23 of the indoor unit 2 and the control unit 37 of the outdoor unit 3. The control unit 23 of the indoor unit 2 (hereinafter referred to as “indoor control unit 23”) includes a reception unit 23a that receives a signal from the remote controller 4, an MCU (Micro Controller Unit) 23b, and a transmission unit 23c. .

The user uses the remote controller 4 to determine various operating conditions such as the operation mode of the air conditioner 1 and transmits it to the indoor unit 2 (indoor control unit 23). The receiving unit 23a transmits the received operating condition to the MCU 23b. The MCU 23b, for example, controls the driving of the indoor fan 22 via the driving circuit 23d, or controls the driving of each component device such as the louvers 2e and 2f and the damper via the driving circuit (not shown). Carry out driving based on driving commands from users. Further, the MCU 23b transmits a signal to the outdoor unit 3 through the transmission unit 23c, and the outdoor unit 3 that has received the signal controls driving of the compressor 31 and the like.

The indoor unit 2 and the outdoor unit 3 are electrically connected, and a signal transmitted from the indoor control unit 23 is a receiving unit of the control unit 37 of the outdoor unit 3 (hereinafter referred to as “outdoor control unit 37”). Received by 37a. The received signal is transmitted to the drive circuits 37c to 37g that drive each device constituting the outdoor unit 3 via the MCU 37b. For example, the drive circuit 37 c drives the compressor 31. The drive circuit 37d drives the four-way valve 32, and the drive circuit 37e drives the throttle mechanism 34. Furthermore, the drive circuit 37f drives the switching valve 36, and the drive circuit 37g drives the outdoor fan 38.

Next, the control method of the air conditioner in this embodiment will be described.

As shown in FIG. 4, the compressor 31 is provided with two upper and lower compression chambers 31b and 31f with an intermediate partition plate 31a interposed therebetween. Low pressure refrigerant is supplied to the upper compression chamber 31b through the first supply path M, and the upper rolling piston 31c rotates to compress the refrigerant. An upper vane 31d is pressed against the upper rolling piston 31c by an elastic body (spring) 31e. Therefore, the upper vane 31d reciprocates following the rotation of the upper rolling piston 31c.

The lower compression chamber 31f is supplied with a low-pressure or high-pressure refrigerant through the second supply path N as will be described later. When the low-pressure refrigerant is supplied (FIG. 4), the lower rolling piston 31g rotates to compress the refrigerant into a high-pressure refrigerant and send it to the outdoor heat exchanger 33. A lower vane 31h is pressed against the lower rolling piston 31g by an elastic body (spring: not shown). Therefore, the lower vane 31h reciprocates following the rotation of the lower rolling piston 31g. However, when high-pressure refrigerant is supplied (FIG. 5), the lower vane 31h is held away from the lower rolling piston 31g by the magnetic body 31i, and the lower rolling piston 31g rotates without reciprocation of the lower vane 31h.

FIG. 4 shows a case where two cylinders of the compressor 31 are driven. The term “cylinder” collectively represents mechanisms such as rolling pistons 31c and 31g and vanes 31d and 31h provided in the compression chambers 31b and 31f.

The low-pressure refrigerant flows into the accumulator 35 from the indoor heat exchanger 21 via the four-way valve 32. As described above, the accumulator 35 and the compressor 31 are connected by two systems (first supply path M and second supply path N). The first supply path M directly connects the accumulator 35 and the compressor 31 and supplies low-pressure refrigerant to the upper compression chamber 31b. The refrigerant is compressed by the rotation of the upper rolling piston 31c, becomes a high pressure, and is sent to the outdoor heat exchanger 33.

On the other hand, the refrigerant is supplied to the lower compression chamber 31f through the second supply path N. A switching valve 36 is provided on the second supply path N. For the sake of explanation, the path from the accumulator 35 to the switching valve 36 is referred to as a second supply path N1, and the path from the switching valve 36 to the compressor 31 is referred to as a second supply path N2. A buffer tank 39 is provided on the second supply path N2 to alleviate sudden pressure changes.

In FIG. 4, the switching valve 36 is closed and the second supply path N1 and the second supply path N2 are connected. Accordingly, the low-pressure refrigerant is supplied to the compressor 31 (upper compression chamber 31b) via the first supply path M, and the low-pressure refrigerant is supplied to the compressor 31 (lower compression chamber 31f) via the second supply path N. Is done. In this way, the low-pressure refrigerant is supplied to the upper compression chamber 31b and the lower compression chamber 31f, and the refrigerant is compressed by the rotation of the upper rolling piston 31c and the lower rolling piston 31g. The compressed high-pressure refrigerant is supplied to the outdoor heat exchanger 33 via the four-way valve 32. This operation is a so-called two-cylinder operation. For example, the two-cylinder operation is performed when the air conditioner 1 is started or during a medium to high capacity operation.

A bypass path 40 connected to the switching valve 36 is provided in the middle of the pipe connecting the compressor 31 and the four-way valve 32. However, since the switching valve 36 is closed in the above-described case, the high-pressure refrigerant that satisfies the bypass passage 40 is not supplied to the second supply passage N2.

2, four arrows O, P, Q, and R are shown around the switching valve 36 in the circuit of the refrigeration cycle A shown in FIG. In the two-cylinder operation of FIG. 4, since the switching valve 36 is closed, the low-pressure refrigerant passes through the accumulator 35 and is supplied to the compressor 31 (lower compression chamber 31f) through the buffer tank 39 as indicated by the arrow O. Is done. The high-pressure refrigerant that has entered the bypass passage 40 from the compressor 31 ends at the switching valve 36 as indicated by the arrow Q because the switching valve 36 is closed.

FIG. 5 shows the operating state of the compressor 31 in the cool breeze operation mode. “Cool wind operation” refers to an operation of blowing cool air into the installation space of the air conditioner 1 (indoor unit 2). The indoor unit 2 sucks indoor air, exchanges heat with the indoor heat exchanger 21, and blows out the heat-exchanged air into the room. In “cool wind operation”, air that is about 5 ± 1 ° C. lower than the air temperature taken in by the indoor unit 2 is blown into the room.

That is, the cool air operation mode is located between the “blower operation mode” in which there is no difference between the suction temperature and the blowout temperature and the “cooling operation mode” in which cool air having a large difference between the suction temperature and the blowout temperature is supplied. By instructing the air conditioner 1 to perform a cool air operation, it is possible to prevent the adverse effect of the user being too cold.

In conventional cool air operation, the operation frequency of the compressor is minimized and the indoor heat exchanger is controlled. However, depending on the capacity of the compressor, cold air is supplied even during operation at the minimum operation frequency. It is as described above. Therefore, in this embodiment, in addition to the operation at the minimum operation frequency, the number of drive cylinders of the compressor 31 is further minimized, thereby reducing the amount of refrigerant flowing in the refrigeration cycle and preventing overcooling. Provide a comfortable space for the elderly.

Specific explanation. As shown in FIG. 5, a high-pressure refrigerant is supplied to the lower compression chamber 31f. That is, a part of the high-pressure refrigerant supplied from the compressor 31 to the outdoor heat exchanger 33 is supplied to the lower compression chamber 31f via the bypass passage 40, the switching valve 36, and the second supply passage N2. Since the switching valve 36 is opened, the high-pressure refrigerant flows through such a path. In this case, the low-pressure refrigerant from the accumulator 35 enters the second supply path N1, but is not supplied to the lower compression chamber 31f because it terminates at the switching valve 36.

The above-described cool air operation will be described again based on the circuit of the refrigeration cycle A shown in FIG. In the one-cylinder operation shown in FIG. 5, the switching valve 36 is opened. Therefore, the low-pressure refrigerant passes through the accumulator 35, but ends at the switching valve 36 as indicated by the arrow R. On the other hand, the high-pressure refrigerant that has entered the bypass passage 40 from the compressor 31 is supplied to the compressor 31 (lower compression chamber 31f) via the buffer tank 39 as indicated by the arrow P because the switching valve 36 is closed.

A pressure (discharge pressure: high pressure) inside the compressor 31 acts as a back pressure on the lower vane 31h of the lower compression chamber 31f, and is pressed against the lower rolling piston 31g by the back pressure and the elastic force of the spring. It was. When the low-pressure refrigerant is supplied to the lower compression chamber 31f, the above-described back pressure acts effectively, so the lower vane 31h is pressed against the lower rolling piston 31g (FIG. 4). However, in the cool breeze operation mode (FIG. 5), the high-pressure refrigerant is supplied to the lower compression chamber 31f, so the back pressure described above does not work effectively. For this reason, the lower vane 31h is separated from the lower rolling piston 31g and held by the magnetic force of the magnetic body 31i. As a result, the lower rolling piston 31g idles in the lower compression chamber 31f.

That is, since the lower rolling piston 31g does not work to compress the refrigerant, the one-cylinder operation is performed only in the upper compression chamber 31b. In this state, the amount of refrigerant to be compressed decreases, so the amount of refrigerant discharged to the outdoor heat exchanger 33 decreases.

FIG. 6 is a flowchart of the control in the cool breeze operation mode. First, the user operates the remote controller 4 to select the cool wind operation mode. For example, this operation is performed by long-pressing the “cooling” button of the remote controller 4. FIG. 1 shows the state changed to the cool wind operation mode, and “cool wind” is displayed on the display unit 4a. From the remote controller 4, a cool wind operation mode start command (signal) is transmitted to the receiving unit 23a of the indoor unit 2 (ST1).

The receiving unit 23a transmits the cool wind operation start command received from the remote controller 4 to the outdoor control unit 37a via the MCU 23b and the transmitting unit 23c. The receiving unit 37a transmits the received cool wind operation start command to the MCU 37b. The MCU 37b compares the preset temperature with the outdoor temperature (ST2).

The preset temperature is a temperature (for example, 35 ° C.) for determining whether or not to start the cool wind operation, and is stored in the MCU 37b. The preset temperature can be arbitrarily set in consideration of the installation location of the air conditioner 1 and the like. The outdoor temperature is measured by the outside air temperature sensor 50 and transmitted to the MCU 37b.

When the MCU 37b compares the outdoor temperature with the preset temperature and determines that the outdoor temperature is lower than the preset temperature (NO in ST2), the MCU 37b does not shift to the cool wind operation mode even if the cool wind operation start command is received. To wait. Therefore, in this case, the operation mode immediately before the cool wind operation mode is selected is continued.

On the other hand, if the MCU 37b determines that the outdoor temperature is equal to or higher than the preset temperature (YES in ST2), it switches the number of drive cylinders of the compressor 31 from 2 cylinders to 1 cylinder and operates at the minimum operating frequency. Start. That is, cool air operation is started (ST3).

In addition, immediately after the start of the cool breeze operation, the two-cylinder operation is executed for about 10 minutes at a frequency (for example, around 20 Hz) about twice the minimum operation frequency to protect the compressor 31. Thereafter, a two-cylinder operation at the minimum frequency (for example, around 10 Hz) is executed until 19 minutes after the start, and after a lapse of 19 minutes, the operation shifts to a one-cylinder operation at the minimum frequency (stable operation).

Actually, the MCU 37b switches the switching valve 36 from the closed state (FIG. 4) to the open state (FIG. 5) via the drive circuit 37d, and the high-pressure refrigerant is supplied to the lower compression chamber 31f. When the high-pressure refrigerant is supplied to the lower compression chamber 31f, as described above, the lower vane 31h is held by the magnetic body 31i, and the lower rolling piston 31g idles to perform one cylinder operation. By operating the compressor 31 in this manner, the amount of refrigerant flowing through the refrigeration cycle A is reduced, and the amount of refrigerant that is heat-exchanged by the indoor heat exchanger 21 is reduced. As a result, not “cold wind” but “cool wind” is supplied to the room.

The MCU 37b continues the cool breeze operation unless it receives a cool breeze operation end command from the indoor control unit 23 (NO in ST4). The cool wind operation end command is transmitted, for example, when the user presses and holds down the “cooling” button again to cancel the cool wind operation mode and select the cooling operation mode. When another operation mode is selected in this way, the command is transmitted to the outdoor control unit 37 as a cool wind operation end command.

When the MCU 37b receives the cool wind operation end command (YES in ST4), the cool wind operation is ended. That is, the operation with the frequency according to the load is performed while the one cylinder operation is performed, or the operation with the frequency according to the load is performed by shifting from the one cylinder operation to the two cylinder operation (ST5).

The transition to 2-cylinder operation is actually performed as follows. First, the switching valve 36 is switched from the open state (FIG. 5) to the closed state (FIG. 4) via the drive circuit 37d. As a result, the supply of the high-pressure refrigerant to the lower compression chamber 31f is completed, the second supply path N1 and the second supply path N2 are connected, and the low-pressure refrigerant is supplied to the lower compression chamber 31f via the accumulator 35. Due to the supply of the low-pressure refrigerant, the lower vane 31h moves away from the magnetic body 31i, contacts the lower rolling piston 31g, and follows the rotation of the lower rolling piston 31g. In this way, the compressor 31 shifts to the 2-cylinder operation.

The measurement results of various data after the start of operation in the cool air operation mode of the air conditioner are shown in FIG. 7 (graph) and Table 1 below. In addition, the said measurement is a result at the time of installing the indoor unit 2 in a 12.5 tatami room, and performing the cool wind operation. Further, the room temperature at the start was about 33 ° C. (= outside temperature) and the humidity was 70%.

In the graph of FIG. 7, “temperature (° C.)” is plotted on the left vertical axis, “power (W)” is plotted on the right vertical axis, “time (min)” is plotted on the horizontal axis, “suction temperature”, and “room average temperature”. ”,“ Blowout temperature ”, and“ Power ”are shown as temporal transitions. Table 1 also shows specific numerical values such as the set temperature and power consumption for each time. The front panel 2a of the indoor unit 2 is provided with an energy monitor that displays the power consumption at that time and the like so that the user can check the driving state. The item “energy monitor display value” in Table 1 is a numerical value (displayed in increments of 5 W) displayed on this monitor.

As shown in the graph of FIG. 7, when the cool air operation is started, first, so that the difference between the blowing temperature and the suction temperature is stabilized in a short time with a cool air temperature difference (for example, about 5 ± 1 ° C.), It is controlled by setting the blowout temperature low. For example, when 10 minutes have elapsed from the start, the suction temperature is 22.2 ° C. while the suction temperature is 32.2 ° C. as shown in Table 1. In addition, since the room temperature is rapidly lowered at this time, the power consumption is as large as “219 W”.

On the other hand, as shown in the graph of FIG. 7, after about 20 minutes, the power consumption of the compressor 31 is stabilized at 56 W. Further, as shown in Table 1, it can be seen that the difference between the suction temperature and the blowout temperature is within the range of the above-mentioned cool air temperature difference of “−4.8 ° C.” after 60 minutes.

As described above, by adopting a compressor that can change the operating capacity, it is possible to prevent overcooling by operating the compressor by further reducing the refrigerant discharge amount in addition to the minimum capacity operation. Comfortable air conditioning can be performed, and operation with reduced energy consumption is also possible.

In particular, when the compressor shifts from the two-cylinder operation to the one-cylinder operation, the indoor unit can supply cool air having a blowing temperature that is not excessively cooled from the indoor temperature (suction temperature) into the room, coupled with the minimum frequency operation. it can. For this reason, while supplying the air which feels cool to a user, the bad influence by too cold is not given. Such operation also saves energy in the operation of the compressor.

In addition, this invention is not limited to the said embodiment, A component can be deform | transformed and embodied within the range of the summary. For example, in the above embodiment, it is determined whether or not the outdoor control unit starts the cool wind operation mode, but the indoor control unit may determine.

Further, a plurality of components in the above embodiment may be combined as appropriate. For example, you may delete some components from all the components of the said embodiment.

Claims (5)

An air conditioner,
An indoor heat exchanger and an indoor unit equipped with an indoor fan;
A compressor connected to the indoor unit and having a plurality of cylinders and capable of changing the number of operating cylinders, an outdoor heat exchanger, and an outdoor unit including a throttle mechanism;
A control unit that variably controls the operating rotational speed of the compressor,
The control unit sets the number of operating cylinders of the compressor to the minimum number of cylinders based on outside air temperature during cooling operation, and the minimum number of rotations at which the operating speed of the compressor can be operated in a refrigeration cycle The air conditioner can be operated in the operation mode set to In the above operation mode,
The control unit is
Compare the outside temperature obtained by acquiring the outside temperature based on the operation start command and the preset temperature,
When the outside air temperature is equal to or higher than the preset temperature, the number of operating cylinders of the compressor is set to the minimum number of cylinders, and the operating rotational speed of the compressor is set to the minimum in the previous period in which the refrigeration cycle operation can be performed. The air conditioner according to claim 1, wherein the operation is controlled so that the temperature difference between the suction temperature and the blowout temperature of the indoor unit is set to 5 ° C or less by setting the number of rotations. The compressor has the plurality of cylinders in a case;
The inside of the case is the refrigerant discharge pressure,
2. The air conditioner according to claim 1, wherein the control unit supplies a refrigerant having a pressure lower than the refrigerant discharge pressure to the operation cylinder and supplies a refrigerant having the refrigerant discharge pressure to the idle cylinder during the operation mode. The outdoor unit further includes a switching valve 36 for switching a refrigerant supply path to be supplied to the plurality of cylinders of the compressor;
The air conditioner according to claim 3, wherein the control unit switches the switching valve to supply the refrigerant refrigerant discharged from the compressor to the idle cylinder during the operation mode. Each of the plurality of cylinders has a rolling piston and a vane;
The air conditioner according to claim 4, wherein a retracting mechanism is provided in the idle cylinder in the operation mode so as to retract the vane so as not to contact the rolling piston.

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