JP2014173814A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner capable of heightening operation efficiency at the time of start-up even when a refrigerant is in a flooded state.SOLUTION: An air conditioner includes a refrigeration cycle configured by connecting a heat exchanger 1, a pressure-reducing valve 4, a heat exchanger 2, an accumulator 5 and a compressor 6 in an annular shape. The air conditioner includes: a piezoelectric element 8 for atomizing a liquefied refrigerant by applying vibration to the refrigerant in the accumulator 5; flooded state detection devices (9 and 10) for detecting a flooded state at the time of start-up; and a control device 10 for driving the piezoelectric element 8 when the flooded state detection devices (9 and 10) have detected the flooded state.

Description

  The present invention relates to an air conditioner, and more particularly to control in a sleeping state at startup.

  While energy saving is required in recent years, the air conditioner is also required to perform energy saving operation and high efficiency operation. The air conditioner supplies and circulates a refrigerant to the refrigeration cycle, performs heat exchange, and supplies cold air or warm air. By circulating more refrigerant in the refrigeration cycle, high efficiency and energy saving can be achieved.

  However, while the air conditioner is stopped, the refrigeration cycle is also stopped. When this stop period is long and the outside air temperature is low, the vaporized refrigerant present in the refrigeration cycle is liquefied (liquefied refrigerant). When liquefied refrigerant is sucked into the compressor, it may compress the liquid and damage the compressor. Therefore, an accumulator for storing the liquefied refrigerant is disposed in front of the compressor to prevent the liquefied refrigerant from being sucked into the compressor. The For this reason, when the air conditioner is stopped or when the outside air temperature is low, the liquefied refrigerant liquefied from the vaporized state gradually accumulates in the accumulator. When the air conditioner is driven, the liquefied refrigerant accumulated in the accumulator is gradually vaporized and sent to the compressor as the vaporized refrigerant to enter the refrigeration cycle.

As a conventional technique for dealing with such a liquefied refrigerant, for example, an ultrasonic irradiation device for atomizing the liquefied refrigerant and the refrigerating machine oil accumulated at the bottom of the accumulator is provided, and the refrigerating machine oil in the accumulator is compressed in an atomized state. There has been proposed a refrigeration cycle structure that prevents the refrigerating machine oil from being supplied to the compressor due to clogging of the oil return pipe in the accumulator (see, for example, Patent Document 1).
As another conventional technique, a refrigeration apparatus that uses two or more kinds of mixed refrigerants, vibrates the liquefied refrigerant in the accumulator during steady cooling operation, and atomizes it to increase the operation efficiency has been proposed ( For example, see Patent Document 2).

Japanese Utility Model Publication No. 61-027075 Japanese Patent No. 3601122

  As described above, when the air conditioner is stopped for a long time or at a low outside air temperature, the amount of liquefied refrigerant increases. Therefore, when starting the air conditioner, the amount of vaporized refrigerant in the accumulator is small, and the compressor The amount of refrigerant that is sent to the refrigeration cycle is reduced, resulting in inefficient operation. A state where the amount of the liquefied refrigerant is large is called a sleeping state. When the air conditioner starts up in a stagnation state, it becomes a low-efficiency operation, and it takes about an hour to return to the amount of refrigerant supplied to the normal refrigeration cycle. Therefore, raising the efficiency at the time of starting in the sleeping state has been a problem.

However, in the above-mentioned Patent Document 1, there is a description about atomizing the liquefied refrigerant by the ultrasonic irradiation device, but there is no mention of increasing the efficiency at the start-up in the sleeping state.
Also, in the above-mentioned Patent Document 2, there is a description of control for increasing the efficiency at the time of steady load of cooling, but the atomization device is stopped during the start-up operation which is important by increasing the efficiency. For this reason, high-efficiency operation was not possible at startup.

  The present invention has been made against the background of the above problems, and an object of the present invention is to provide an air conditioner that can increase the operation efficiency at the time of startup even when the refrigerant is in a stagnation state at the time of startup. To do.

  An air conditioner according to the present invention is an air conditioner including a refrigeration cycle in which a use side heat exchanger, a pressure reducing device, a heat source side heat exchanger, an accumulator, and a compressor are connected in an annular shape, and the accumulator includes The vibration device that vibrates the refrigerant to atomize the liquefied refrigerant, the sleep state detection device that detects the sleep state at the time of activation, and when the sleep state detection device detects the sleep state, the vibration device is And a control device for driving.

  According to the air conditioner of the present invention, if the liquefied refrigerant in the accumulator is vibrated and atomized when it is in a stagnation state at the time of activation, vaporization of the liquefied refrigerant is promoted and activated. The operating efficiency can be increased by increasing the amount of refrigerant at the time. Conventionally, low-efficiency operation has been performed for one hour or more after startup, but according to the present invention, such low-efficiency operation is eliminated and high-efficiency operation is possible.

It is a refrigerant circuit figure of the air harmony device concerning Embodiment 1 of the present invention. It is a related figure of the elapsed time at the time of starting and discharge pressure in Embodiment 1 of the present invention. It is a flowchart which shows operation | movement of the control apparatus at the time of starting in Embodiment 1 of this invention. It is a related figure of the elapsed time at the time of starting and suction pressure in Embodiment 2 of the present invention. It is a flowchart which shows operation | movement of the control apparatus at the time of starting in Embodiment 2 of this invention. It is a relationship figure between the elapsed time at the time of starting in Embodiment 3 of this invention, and temperature difference (DELTA) T of the room temperature with respect to the preset temperature of an indoor unit. It is a flowchart which shows operation | movement of the control apparatus at the time of starting in Embodiment 3 of this invention.

Embodiment 1 FIG.
FIG. 1 is a refrigerant circuit diagram of the air-conditioning apparatus according to Embodiment 1 of the present invention.
As shown in FIG. 1, an air conditioner includes a heat exchanger (use side heat exchanger) 1, a heat exchanger (heat source side heat exchanger) 2, a four-way valve 3, a pressure reducing valve (LEV) 4, and an accumulator 5. And a compressor 6, which are annularly connected by the refrigerant pipe of FIG. 1 to constitute a refrigeration cycle. The heat exchanger 1 is a utilization side heat exchanger that is housed in an indoor unit (not shown) and functions as a condenser (heating) or an evaporator (cooling) depending on the setting of the four-way valve 3. The heat exchanger 2 is a heat source side heat exchanger that functions as an evaporator (during heating) or a condenser (during cooling) depending on the setting of the four-way valve 3. The four-way valve 3 is a valve that changes the flow of refrigerant in order to switch between heating and cooling. The solid line in FIG. 1 indicates the state during heating, and the broken line indicates the state during cooling. The pressure reducing valve (LEV) 4 reduces the pressure in the pipe. The accumulator 5 stores the liquefied refrigerant 7 so as not to send the liquefied refrigerant 7 to the compressor 6. The compressor 6 compresses and discharges the sucked refrigerant.

  In the present embodiment, the piezoelectric element 8 is attached to the bottom of the accumulator 5. The piezoelectric element 8 vibrates and atomizes the liquefied refrigerant 7 stored in the accumulator 5. A pressure sensor 9 is provided on the discharge side of the compressor 6. The pressure sensor 9 detects the discharge pressure of the compressor 6. The output of the pressure sensor 9 is sent to the control device 10. The control device 10 is composed of, for example, a microcomputer. In this Embodiment 1, the pressure sensor 9 and the control apparatus 10 comprise the sleep state detection apparatus of this invention. 1 shows the pressure sensor 12 and the temperature sensor 13, the pressure sensor 12 is used in a second embodiment described later, and the temperature sensor 13 is used in a third embodiment described later. is there.

The operation of the air conditioner of FIG. 1 will be described.
During the heating operation, the four-way valve 3 is switched as shown by a solid line, and is circulated through a path of the compressor 6, the heat exchanger 1, the pressure reducing valve 4, the heat exchanger 2, the accumulator 5, and the compressor 6. Flows. And the heat exchanger 1 functions as a condenser and heats the surrounding air.
Further, during the cooling operation, the four-way valve 3 is switched as indicated by a broken line, and circulates through a path of the compressor 6, the heat exchanger 2, the pressure reducing valve 4, the heat exchanger 1, the accumulator 5, and the compressor 6. Refrigerant flows. The heat exchanger 1 functions as an evaporator to cool the surrounding air.

Next, the operation | movement at the time of starting of the air conditioning apparatus of FIG. 1 is demonstrated.
FIG. 2 is a relationship diagram between the elapsed time at startup and the discharge pressure, and FIG. 3 is a flowchart showing the operation of the control device 10 at startup.
As shown in FIG. 2, in the case of startup where there is a lot of vaporized refrigerant in the accumulator 5, the discharge pressure Pd increases immediately after startup. However, in the case of activation in the sleeping state, the discharge pressure Pd remains low, and it takes one hour or more until the pressure rises to the normal activation pressure value. In the present embodiment, the sleeping state is detected using such a property of the discharge pressure Pd. Details thereof will be described with reference to FIG.

  As shown in FIG. 3, first, the air conditioner (compressor 6) is started (S1). It is determined whether or not an elapsed time after activation has passed a set time (for example, about 10 minutes) (S2). If the set time (for example, about 10 minutes) has elapsed, then the output of the pressure sensor 9 is taken in and it is determined whether or not the discharge pressure Pd is lower than a preset set pressure value (S3). . When the discharge pressure Pd is lower than a preset pressure value set in advance, it is determined that the refrigerant is in the stagnation state in the accumulator 5, and the stagnation state is detected (S3, Yes). Then, the piezoelectric element 8 is driven (S4), and the accumulator 5 is vibrated to atomize the refrigerant. The atomized refrigerant is more easily vaporized than the liquefied refrigerant, and since the pressure in the accumulator 5 starts to decrease as the compressor 6 starts, the refrigerant is vaporized from the atomized state. The vaporized refrigerant is sucked into the compressor 6 and enters the refrigeration cycle. When the above process is repeated and the liquefied refrigerant is vaporized to some extent, the discharge pressure Pd increases, and when the discharge pressure Pd exceeds the set pressure value (S3: No), sufficient refrigerant is supplied and circulated to the refrigeration cycle. The driving of the piezoelectric element 8 is stopped (S5).

  As described above, in the present embodiment, the discharge pressure Pd is monitored, and when the discharge pressure Pd is lower than the set pressure value (threshold value), the liquefied refrigerant in the accumulator 5 is atomized as being in a stagnation state. Since the vaporization is promoted and the vaporized refrigerant is supplied to the refrigeration cycle, the efficiency at the time of starting the air conditioner can be increased even in the sleeping state. In particular, when the heating operation is performed at a low outside temperature, the effect of the first embodiment is remarkable. The same applies to the second and third embodiments described later.

Embodiment 2. FIG.
In the first embodiment, the example in which the discharge pressure Pd is monitored has been described. In the second embodiment, an example in which the suction pressure Ps is monitored to improve the efficiency at startup will be described. The refrigerant circuit diagram of FIG. 1 is similarly applied to the second embodiment, and the pressure sensor 12 of FIG. 1 is a sensor used in the present embodiment and detects the suction pressure of the compressor 6. In the second embodiment, the pressure sensor 12 and the control device 10 constitute a sleeping state detection device of the present invention.
FIG. 4 is a relationship diagram between the elapsed time at startup and the suction pressure, and FIG. 5 is a flowchart showing the operation of the control device 10 at startup.

  As shown in FIG. 4, in the start-up in which there is a lot of vaporized refrigerant in the accumulator 5, the suction pressure Ps once decreases after the start-up, but the suction pressure Ps immediately increases. However, in the case of activation in the sleep state, after the suction pressure Ps has decreased, it takes one hour or more for the suction pressure Ps to increase. In the present embodiment, the sleeping state is detected using such a property of the suction pressure Ps. Details thereof will be described with reference to FIG.

  As shown in FIG. 5, first, the air conditioner is activated (S1). It is determined whether or not an elapsed time after activation has passed a set time (for example, about 10 minutes) (S2). If the set time (for example, about 10 minutes) has elapsed, the output of the pressure sensor 12 is taken in, and it is determined whether or not the suction pressure Ps is lower than a preset set pressure value (S3a). . When the suction pressure Ps is lower than the set pressure value, it is determined that the refrigerant is in the sleeping state in the accumulator 5, and the sleeping state is detected (S3a, Yes). Then, the piezoelectric element 8 is driven (S4), and the accumulator 5 is vibrated to atomize the refrigerant. The atomized refrigerant is more easily vaporized than the liquefied refrigerant, and since the pressure in the accumulator 5 starts to decrease as the compressor 6 starts, the refrigerant is vaporized from the atomized state. The vaporized refrigerant is sucked into the compressor 6 and enters the refrigeration cycle. When the liquefied refrigerant is vaporized to some extent, the suction pressure Ps increases, and when the suction pressure Ps exceeds the set pressure value (S3a: No), it is determined that sufficient refrigerant has been supplied and circulated to the refrigeration cycle, and the piezoelectric element 8 Is stopped (S5).

  As described above, in the present embodiment, the suction pressure Ps is monitored, and when the suction pressure Ps is lower than a preset pressure value, it is assumed that the refrigerant is in a stagnation state and the liquefied refrigerant in the accumulator 5 The vaporization is promoted and vaporization is promoted, and the vaporized refrigerant is supplied to the refrigeration cycle. Therefore, the efficiency of starting the air conditioner can be increased even in the sleeping state.

Embodiment 3 FIG.
In the first embodiment and the second embodiment described above, the example in which the discharge pressure or the suction pressure is monitored has been described. However, in the third embodiment, the temperature difference between the room temperature and the set temperature is monitored, and the efficiency at the time of starting is monitored. An example of improvement will be described. The refrigerant circuit diagram of FIG. 1 is similarly applied to the third embodiment, and the temperature sensor 13 of FIG. 1 is a sensor used in the present embodiment, and is an indoor unit in which the heat exchanger 1 is housed. (Not shown) detects the temperature of the air-conditioned room. In the third embodiment, the temperature sensor 13 and the control device 10 constitute the sleeping state detection device of the present invention.

  FIG. 6 is a relationship diagram of the elapsed time since the start and the temperature difference ΔT of the room temperature with respect to the set temperature of the indoor unit, and FIG. 7 is a flowchart showing the operation of the control device 10 at the start.

  As shown in FIG. 6, in the case of startup where there is a large amount of vaporized refrigerant in the accumulator 5, since a large amount of refrigerant is supplied to the refrigeration cycle after startup, efficient operation is performed, and the room temperature is It can be operated so as to approach the set temperature of the indoor unit in a short time, and the temperature difference ΔT between the room temperature and the set temperature of the indoor unit is reduced in a short time. However, in the case of start-up in the sleeping state, the amount of refrigerant supplied to the refrigeration cycle is small, so the efficiency is poor, and it takes more than one hour for the room temperature to approach the set temperature, and the temperature difference ΔT is short. It does not get smaller with time. In the present embodiment, the sleeping state is detected using such a property of the temperature difference ΔT. Details thereof will be described with reference to FIG.

  As shown in FIG. 7, first, the air conditioner is activated (S1). It is determined whether or not an elapsed time after activation has passed a set time (for example, about 10 minutes) (S2). When the set time (for example, about 10 minutes) has elapsed, the output of the temperature sensor 13 is taken in and the set value of room temperature−room temperature = ΔT is obtained (S3c). And it is judged whether this temperature difference (DELTA) T is larger than the preset temperature difference (target value) (S3d). When the temperature difference ΔT is larger than the set temperature difference, it is determined that the refrigerant in the accumulator 5 is in the sleeping state, and the sleeping state is detected (S3d: Yes). Then, the piezoelectric element 8 is driven (S4), and the accumulator 5 is vibrated to atomize the refrigerant. The atomized refrigerant is more easily vaporized than the liquefied refrigerant, and since the pressure in the accumulator 5 starts to decrease as the compressor 6 starts, the refrigerant is vaporized from the atomized state. The vaporized refrigerant is sucked into the compressor 6 and enters the refrigeration cycle. When the liquefied refrigerant evaporates to some extent, the temperature difference ΔT value decreases. When the temperature difference ΔT is equal to or less than the set temperature difference, it is determined that sufficient refrigerant has been supplied and circulated to the refrigeration cycle, and the driving of the piezoelectric element 8 is stopped (S5).

  As described above, in the third embodiment, the temperature difference ΔT of the room temperature with respect to the set temperature of the indoor unit is monitored, and if the temperature difference ΔT is larger than the set temperature difference, the refrigerant is assumed to be in a stagnation state. Since the liquefied refrigerant in the accumulator 5 is vaporized and the refrigerant is supplied to the refrigeration cycle, the efficiency at the start-up of the air conditioner can be increased even in the sleeping state.

  In the above description, an example in which a piezoelectric element is used as the vibration device that atomizes the liquefied refrigerant has been described. However, the liquid refrigerant may be vibrated by an ultrasonic vibrator to be atomized. Further, the installation positions of the pressure sensors 9 and 12 are not limited to the positions shown in FIG. 1, and may be any part that can detect a pressure corresponding to the discharge pressure or the suction pressure.

  DESCRIPTION OF SYMBOLS 1 Heat exchanger, 2 Heat exchanger, 3 Four way valve, 4 Pressure reducing valve (LEV), 5 Accumulator, 6 Compressor, 7 Liquefied refrigerant, 8 Piezoelectric element, 9, 12 Pressure sensor, 10 Control apparatus, 13 Temperature sensor.

Claims (4)

In an air conditioner including a refrigeration cycle in which a use side heat exchanger, a pressure reducing device, a heat source side heat exchanger, an accumulator, and a compressor are connected in an annular shape,
A vibration device that vibrates the refrigerant in the accumulator to atomize the liquefied refrigerant;
A sleep state detection device that detects a sleep state at startup; and
An air conditioner comprising: a control device that drives the vibration exciter when the sleep state detection device detects a sleep state. The air conditioner according to claim 1, wherein the stagnation state detection device monitors a discharge pressure of the compressor and detects a stagnation state based on the discharge pressure at the time of activation. 2. The air conditioning apparatus according to claim 1, wherein the stagnation state detection device monitors a suction pressure of the compressor and detects a stagnation state based on the suction pressure at the time of activation. The air conditioner according to claim 1, wherein the sleeping state detection device monitors a temperature difference of a room temperature with respect to a set temperature of the indoor unit at the time of activation, and detects the sleeping state based on the temperature difference.

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