JPH0743175B2 - Air conditioner - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a split type air conditioner having a refrigerant recovery operation function from an indoor unit to an outdoor unit.

[Technical background of the invention]

Generally, in a split type air conditioner, a heat pump refrigeration cycle in which a variable capacity compressor, a four-way valve, an outdoor heat exchanger, an electric expansion valve, an indoor heat exchanger, a packed valve, etc. are sequentially connected. And an at least variable capacity compressor, a four-way valve, an outdoor heat exchanger, an electric expansion valve, and a packed valve constitute an outdoor unit, and at least an indoor heat exchanger constitutes an indoor unit. There are some that enable refrigerant recovery operation.

In this refrigerant recovery operation, the four-way valve is set to the cooling position, and the refrigerant passage from the outdoor heat exchanger to the indoor heat exchanger is blocked by fully closing the electric expansion valve, while the packed valve is opened. With this, a refrigerant flow path from the indoor heat exchanger to the variable capacity compressor is secured, and in this state, the operation of the variable capacity compressor is turned on to recover the refrigerant from the indoor unit to the outdoor unit. Then, after the operation of the variable capacity compressor is turned on for a predetermined time, for example, 30 seconds or
When 60 seconds have passed, the packed valve is closed, and the refrigerant flow path between the indoor heat exchanger and the variable capacity compressor is shut off to complete the refrigerant recovery.

That is, by performing the refrigerant recovery operation to recover all the refrigerant in the indoor unit into the outdoor unit, the air conditioner main body can be easily relocated when moving.

[Problems of background technology]

By the way, in such an air conditioner, during normal cooling or heating operation, the operating frequency F of the variable capacity compressor changes between a predetermined maximum operating frequency Fmax and minimum operating frequency Fmin according to the air conditioning load. By doing so, the optimum capacity corresponding to the air conditioning load is obtained and the comfort and the energy saving effect are improved.However, since the operation frequency control is also performed in the refrigerant recovery operation, It was inconvenient.

That is, when the variable capacity compressor is operated at the minimum operation frequency Fmin during the refrigerant recovery operation, the recovery capacity is low, and the refrigerant recovery will not be completed within about 30 to 60 seconds until the packed valve is closed.

Further, when the variable capacity compressor operates at the maximum operating frequency Fmax, this time the refrigerant recovery ends early and the variable capacity compressor performs vacuum operation.

Here, FIG. 8 shows the relationship between the operating frequency F of the variable capacity compressor and the amount of oil supply to the bearing portion of the rotor of the variable capacity compressor. Is the change in the amount of oil supply during vacuum operation. In other words, the variable capacity compressor supplies the lubricating oil to the bearing of the rotor by the centrifugal force based on the rotation of the rotor.At the minimum operating frequency Fmin, the amount of oil supply decreases because the suction force is small, and at the maximum operating frequency Fmax. Since the suction force is too large and the lubricating oil becomes mist, the amount of oil supply also decreases. in this case,
Minimum operating frequency Fm if the variable capacity compressor is operating normally
Although the reduction in the amount of lubrication at in and the maximum operating frequency Fmax is not so great, the amount of lubrication is significantly reduced in the vacuum operation. Therefore, as described above, when the variable capacity compressor is in vacuum operation due to the completion of refrigerant recovery as described above, when the operating frequency F of the variable capacity compressor becomes the minimum operating frequency Fmin or the maximum operating frequency Fmax, the amount of lubrication becomes worst. There will be a shortage and the bearing will be seized.

[Object of the Invention]

The present invention has been made in view of the above circumstances,
The purpose of this is to provide an air conditioner with excellent safety and reliability that can reliably complete refrigerant recovery within a prescribed time without causing seizure in the rotor bearing of the variable capacity compressor. To provide.

[Outline of Invention]

The present invention relates to a refrigeration cycle in which a variable capacity compressor, an outdoor heat exchanger, an electric expansion valve, an indoor heat exchanger, a packed valve, and the like are sequentially connected, and an outdoor heat exchanger provided near the outdoor heat exchanger. A fan, at least the variable capacity compressor, an outdoor heat exchanger, an electric expansion valve, a packed valve,
An outdoor unit having an outdoor fan, an indoor unit having at least the indoor heat exchanger, a gas recovery switch, and when the gas recovery switch is turned on, the electric expansion valve is fully closed and the packed valve is set to a predetermined position. Opening for a time, operating the variable capacity compressor at a constant operating frequency between the maximum operating frequency and the minimum operating frequency, and operating the outdoor fan to perform refrigerant recovery operation from the indoor unit to the outdoor unit. And a means for stopping the operation of the variable capacity compressor and the outdoor fan when a predetermined time longer than the opening time of the packed valve has passed after the gas recovery switch was turned on.

Example of Invention

An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the variable capacity compressor 1, the four-way valve 2, the outdoor heat exchanger 3, the electric expansion valve 4, the indoor heat exchanger 5, and the gas side packed valve (electromagnetic on-off valve) 6 are sequentially arranged. A heat pump type refrigeration cycle is formed in communication with each other. That is, during the cooling operation, the refrigerant flows in the direction indicated by the solid line arrow to form a cooling cycle, and during the heating operation, the four-way valve 2 is switched to cause the refrigerant to flow in the direction indicated by the broken line arrow to form the heating cycle. It has become so.
An outdoor fan 7 is provided near the outdoor heat exchanger 3, and an indoor fan 8 is provided near the indoor heat exchanger 5. Thus, at least variable capacity compressor 1, four-way valve
2, outdoor heat exchanger 3, electric expansion valve 4, gas side packed valve
The outdoor unit A is constituted by the outdoor fan 7 and the like. Further, at least the indoor heat exchanger 5 and the indoor fan 8 configure the indoor unit B.
The electric expansion valve 4 of the outdoor unit A and the indoor heat exchanger 5 of the indoor unit B are connected by a transition pipe 10. Furthermore, the indoor heat exchanger 5 of the indoor unit B
Similarly, a crossover pipe 10 connects between the outdoor unit A and the gas side packed valve 6.

FIG. 2 shows a control circuit.

Reference numeral 20 denotes a commercial AC power supply. The indoor control unit 30 is connected to the power supply 20, and the indoor control unit 30 and the power supply line are connected.
The outdoor control unit 40 is connected via 21. A serial signal line 22 for information transfer is provided between the indoor control unit 30 and the outdoor control unit 40.

The operation control section 23 and the indoor fan motor 8M are connected to the indoor control section 30. The indoor control unit 30 includes a microcomputer and its peripheral circuits, and the like, and the outdoor control unit uses the serial signal line 22 to issue an operation control command according to the operating state of the operation operation unit 23 and the temperature detected by an indoor temperature sensor (not shown). Transferred to 40,
It controls the indoor fan motor 8M. Further, the outdoor control unit 40 includes a gas recovery switch 24 and an outdoor fan motor 7
The M, the four-way valve 2, the gas side packed valve 6, and the inverter circuit 25 are connected. Here, the outdoor control unit 40 is the third
As shown in the figure, the DC voltage Vc (+ 5V) is applied to the series circuit of the gas recovery switch 24 and the resistor 42, and the voltage generated at the resistor 42 is supplied to the input port (12) of the microcomputer 41. The outdoor fan motor 7 is instructed by the microcomputer 41 in response to an input signal to the input port (12) and an operation control signal from the indoor control unit 30.
It controls the M, the four-way valve 2, the gas side packed valve 6, the inverter circuit 25, and the like. The inverter circuit 25 converts the commercial AC power supply voltage into AC power having a frequency (and voltage) according to a command from the outdoor control unit 40 and supplies the AC power to the compressor motor 1M.

Next, the operation of the above structure will be described with reference to FIGS. 4 and 5.

When the user or maintenance person turns on the gas recovery switch 24, the outdoor control unit 40 first sets the four-way valve 2 to the cooling position,
The electric expansion valve 4 is fully closed and the gas side packed valve 6 is opened. In this case, the refrigerant passage from the outdoor unit A to the indoor unit B is blocked by fully closing the electric expansion valve 4, while the refrigerant passage from the indoor unit B to the indoor unit A is opened by opening the gas side packed valve 6. Is secured. In addition, the outdoor control unit 40 uses the inverter circuit 25.
To turn on the variable capacity compressor 1 and turn on the outdoor fan 7. In this case, the output frequency of the inverter circuit 25, that is, the operating frequency F of the variable capacity compressor 1 is kept constant at a value Fa (see FIG. 8) which is approximately halfway between the maximum operating frequency Fmax and the minimum operating frequency Fmin.

In this way, when the variable capacity compressor 1 is turned on, the refrigerant in the indoor unit B is recovered by the outdoor unit A. After a lapse of a predetermined time, for example, 30 to 60 seconds from the start of this refrigerant recovery operation, the outdoor control unit 40 closes the gas side packed valve 6 and the refrigerant flow path between the outdoor unit A and the indoor unit B. Shut off completely. Then, when the gas recovery switch 24 is turned off, the outdoor control unit 40
Turns off the variable capacity compressor 1 and the outdoor fan 7.

In this way, during the refrigerant recovery operation, the operating frequency F of the variable capacity compressor 1 is constantly maintained at a value Fa (40 Hz to 90 Hz) which is substantially intermediate between the maximum operating frequency Fmax and the minimum operating frequency Fmin. A necessary and sufficient refrigerant recovery capacity can be obtained, and the refrigerant recovery can be completed within the time until the gas side packed valve 6 is closed. Moreover, since the operating frequency is constant Fa, the lubrication characteristics for the bearing portion of the variable capacity compressor 1 become the best, and even if the variable capacity compressor 1
Even in the vacuum operation, a sufficient amount of oil can be supplied to the bearing portion of the rotor, and seizure of the bearing portion can be prevented.

Although the electromagnetic on-off valve is used as the gas side packed valve 6 in the above embodiment, a manual on-off valve may be used.

Further, in the above embodiment, the operation of the variable capacity compressor 1 and the outdoor fan 7 is made to depend on the off operation of the recovery switch 24 by the user or maintenance personnel during the refrigerant recovery operation, but the off operation is forgotten. If the operation of the variable capacity compressor 1 is interrupted for too long, the amount of oil supplied to the bearing portion of the rotor of the variable capacity compressor 1 is reduced as shown in FIG. 6, and there is a risk of seizure of the bearing portion. is there. To cope with this, as shown in FIG. 7, when the fixed time has elapsed from the start of the refrigerant recovery operation, the operations of the variable capacity compressor 1 and the outdoor fan 7 are turned off regardless of the state of the gas recovery switch 24. The refrigerant recovery operation can be reliably completed within a predetermined time while avoiding the dangers described above, and the safety and reliability are excellent.

Besides, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention.

〔The invention's effect〕

As described above, according to the present invention, it is possible to surely complete the refrigerant recovery within a predetermined time without seizing the bearing portion of the rotor of the variable capacity compressor, which is excellent in safety and reliability. An air conditioner can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a refrigeration cycle and its peripheral portion in an embodiment of the present invention, FIG. 2 is a diagram showing a configuration of a control circuit in the same embodiment, and FIG. 3 is a main part in FIG. FIG. 4 is a flow chart for explaining the operation of the embodiment, FIG. 5 is a time chart for explaining the operation of the embodiment, and FIG. 6 is a general variable capacity compression. Showing the relationship between the operating time of the machine and the amount of oil supplied to its bearing, FIG. 7 is a flow chart for explaining the operation of another embodiment of the present invention, and FIG. 8 is the operation of a general variable capacity compressor. It is a figure which shows the relationship between a frequency and the amount of oil supply with respect to the bearing part. 1 ... Variable capacity compressor, 3 ... Outdoor heat exchanger, 4 ... Electric expansion valve, 5 ... Indoor heat exchanger, 6 ... Gas side packed valve, 10 ... Crossover piping, 24 ... Gas Recovery switch,
30 …… Indoor control unit, 40 …… Outdoor control unit.

Claims (1)

[Claims] 1. A refrigeration cycle in which a variable capacity compressor, an outdoor heat exchanger, an electric expansion valve, an indoor heat exchanger, a packed valve and the like are sequentially connected to each other, and a refrigeration cycle provided in the vicinity of the outdoor heat exchanger. An outdoor fan, an outdoor unit having at least the variable capacity compressor, an outdoor heat exchanger, an electric expansion valve, a packed valve, an outdoor fan, an indoor unit having at least the indoor heat exchanger, and a gas recovery switch, When the gas recovery switch is turned on, the electric expansion valve is fully closed, the packed valve is opened for a predetermined time, and the variable capacity compressor is operated at a constant operating frequency between the maximum operating frequency and the minimum operating frequency. And operating the outdoor fan to perform a refrigerant recovery operation from the indoor unit to the outdoor unit; and, after turning on the gas recovery switch, When longer predetermined time than the opening time of Kkudobarubu has elapsed, the air conditioner characterized by comprising a means for stopping the operation of the variable capacity compressor and outdoor fan.