JPS63286676A - Air conditioner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to the improvement of air conditioners, and particularly to the improvement of defrosting performance for removing frost that adheres to an outdoor heat exchanger during heating operation. .

BACKGROUND ART In winter, an air conditioner that performs heating by operating a heat pump cycle is operated so that heat from the outside air enters the refrigerant at a lower temperature than the outside air in an outdoor heat exchanger. Therefore, frost easily adheres to low-temperature outdoor heat exchangers.
If frost builds up, it will interfere with heat exchange, so it is necessary to defrost it.

5. [A] is a refrigerant circuit diagram of an air conditioner based on Ue, as shown in, for example, Japanese Patent Laid-Open No. 57-169567. In the figure, 1 is a compression allowance, 2 is a four-way valve, 3 is an indoor heat exchanger, 4 is a pressure reducing device, 5 is an outdoor heat exchanger, and 6 is an accumulator. A bypass pipe 7 is provided in the main circuit of the refrigerant for cooling and heating, branching off from the discharge piping of the compressor 1 and joining the pipe between the pressure reducing device 4 and the outdoor heat exchanger 5. There is a bypass pipe 7 in the middle of the bypass pipe 7.
A solenoid valve 8 is provided to open and close the pipeline. This bypass pipe 7 circuit is a defrosting circuit.

FIG. 6 is a sectional view of the accumulator 6.

In the figure, 11 is a pipe leading from the four-way valve 2 to the accumulator 6, 12 is a refrigerant suction pipe of the compressor 1, 13 is a small hole provided in the refrigerant suction pipe 12 near the bottom of the accumulator 6, and 14 is an accumulator This is a liquid reservoir for the refrigerant in 6.

Next, the operation of the conventional air conditioner shown in FIGS. 5 and 6 will be explained. The figure shows the four-way valve 2 in the heating operation position. In heating operation, the high-pressure, high-temperature refrigerant discharged from the compressor 1 flows into the indoor heat exchanger 3 through the four-way valve 2, and releases the refrigerant into the room. The temperature drops to near room temperature and it becomes a liquid. The refrigerant that exits the indoor heat exchanger 3 passes through the pressure reducing device 4 and expands to become a low-pressure, very low-temperature, gas-liquid two-phase refrigerant, which flows into the outdoor heat exchanger 5. Since the refrigerant flowing into the outdoor heat exchanger 5 has a lower temperature than the outside air, it absorbs heat from the outside air and evaporates to become a gas. The refrigerant exiting the outdoor heat exchanger 5 passes through the four-way valve 2, passes through the accumulator 6, is sucked into the compressor 1, is compressed and discharged, and circulates through the circuit in the above order, forming a heat pump cycle for heating operation.

During this heating operation, the outdoor heat exchanger 5 is at a lower temperature than the outside air, so frost adheres and accumulates, interfering with heat exchange. When melting and removing this frost, the solenoid valve 8 is opened. Then, the high-pressure, high-temperature refrigerant discharged from the compressor 1 passes through the bypass pipe 7 and directly flows into the outdoor heat exchanger 5 .

The frost adhering to the outdoor heat exchanger 5 is melted and removed by this high temperature refrigerant. The refrigerant, which has been cooled by heat exchange in the outdoor heat exchanger 5 and has become a gas-liquid two-phase, passes through the four-way valve 2 and enters the pipe]
1 and flows into the accumulator 6. Of the refrigerant that has flowed into the accumulator 6, the gas phase is sucked in through the suction port at the top of the suction pipe 12, and a portion of the liquid phase is sucked into the small hole 1.
3 through the suction pipe 12, and is sucked into the compressor 1 and circulated.

Since there is a large amount of liquid phase refrigerant during the defrosting operation, the excess liquid phase refrigerant is stored in the liquid reservoir 14 outside the suction pipe 12 in the accumulator 6. This prevents the compressor 1 from taking in many hours of liquid phase refrigerant at once and compressing the liquid, thereby preventing damage. When the frost adhering to the outdoor heat exchanger 5 is melted and removed in this way, the solenoid valve 8 is turned off, the circuit of the bypass pipe 7 is turned off, and the heating operation cycle described above is resumed.

[Problems to be Solved by the Invention] The conventional air conditioner is configured as described above, and the temperature of the refrigerant is generally low during defrosting operation, and the J of the liquid phase refrigerant is low.
+) increases in proportion to the gas phase refrigerant star, so more refrigerant than necessary accumulates in the accumulator 6, and the liquid level of the refrigerant exceeds the level shown by the broken line in Fig. 6. ,
There was a risk that the liquid phase refrigerant of the compressor 1 would return to the compressor 1 from the upper end opening of the refrigerant suction pipe 12 all at once, causing the compressor 1 to compress the liquid and be damaged. In order to prevent this, a measure has been taken to greatly increase the internal volume of the accumulator 6 to increase the liquid storage capacity. In addition, if the pressure reducing device 4 is left open in order to prevent liquid refrigerant from returning to the accumulator 6 as much as possible for fear of liquid compression, there are problems such as the refrigerant circulation decreases and the time required for defrosting becomes extremely long. was there.

This invention was made to solve the above-mentioned problems, and even if the volume of the accumulator 6 is reduced, it will not be filled with liquid refrigerant during defrosting operation, and the compressor will still be able to compress the liquid. To provide an air conditioner capable of completing defrosting in a short time without causing defrosting.

[Means for Solving the Problems] The air conditioner according to the present invention sequentially connects the first A pressure device, the receiver, and the second pressure reducing device to the pipe line leading from the indoor heat exchanger to the outdoor heat exchanger. The solenoid valve of the defrost bypass circuit is opened and the first pressure reducing device is closed by the defrosting start signal from the defrosting control unit, and the solenoid valve is closed by the defrosting end signal and the first pressure reducing device is opened. 9 [Function] The air conditioner according to the present invention includes a first pressure reducing device, a receiver, and a second pressure reducing device between the indoor heat exchanger and the outdoor heat exchanger.
A pressure reducing device is provided, and the first pressure reducing device is controlled to be closed during defrosting operation, so there is liquid phase refrigerant in the receiver during heating operation, and when defrosting operation starts, the first pressure reducing device is closed. Since it is closed, the liquid phase medium in the receiver passes through the second pressure reducing device and gradually enters the accumulator via the outdoor heat exchanger.

This can prevent the liquid level of the refrigerant in the accumulator from rising during defrosting operation and causing the compressor to perform liquid compression. Moreover, since the refrigerant is gradually replenished from the receiver as defrosting progresses, there is no shortage of refrigerant circulation, and defrosting can be completed in a short time.

[Embodiments of the invention] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a refrigerant circuit diagram of an air conditioner according to a first embodiment. In the first [4, 1 is a compressor, 2 is a four-way valve, 3
5 is an indoor heat exchanger, 5 is an outdoor heat exchanger, 6 is an accumulator, 7 is a bypass pipe, 8 is a solenoid valve, 15 is a junction where the bypass pipe 7 of the defrosting circuit joins the main circuit for air conditioning, and 21 is a pipe 22 is a receiver having a smaller volume than the volume of the liquid reservoir 14 of the accumulator 6, and 23 is a second pressure reducing device. It is 7. 30 is a defrosting control unit that directly or indirectly detects frost adhering to the outdoor heat exchanger 5 and issues a defrosting command signal. 31 is a solenoid valve driving means for opening the solenoid valve 8 in response to a signal from the defrosting control section 30;
The first pressure reducing device control means opens and closes the pressure reducing device, and the second pressure reducing device control means 33 sets the second pressure reducing device to a predetermined degree of aperture based on a signal from the defrosting control section 30.

Next, the operation of the embodiment shown in FIG. 1 will be explained. In the figure, the four-way valve 2 is in the heating operation position.

During heating operation, the high-pressure, high-temperature refrigerant discharged from the compressor 1 flows into the indoor heat exchanger 3 through the four-way valve 2, radiates heat, and performs the indoor heating function, and the temperature of the refrigerant drops to near room temperature. It becomes a liquid. The refrigerant that has exited the indoor heat exchanger 3 is depressurized by the first pressure reducing device 21 and enters the receiver 22 as a gas-liquid two-phase refrigerant. The refrigerant leaves with priority, and the second pressure reducing device 2
3, the refrigerant is reduced in pressure again and becomes a low-pressure, low-temperature, gas-liquid two-phase refrigerant, which flows into the outdoor heat exchanger 5. This refrigerant has a very low temperature, absorbs heat from the outside air in the outdoor heat exchanger 5, becomes a gas phase, exits the outdoor heat exchanger 5, passes through the four-way valve 2, enters the accumulator 6, and is sucked into the compressor 1 from the accumulator 6. This creates a heat pump cycle in which the refrigerant is discharged and circulated as a high-pressure, high-temperature refrigerant.

The second pressure reducing device 23 adjusts the superheat amount of the refrigerant sucked into the pressure Ia machine 1, and the first pressure reducing device 21 adjusts the subcool J1 of the refrigerant at the outlet of the indoor heat exchanger 3. is set to 9, so the receiver 22
The pressure inside is the discharge pressure Pd of the compressor + the suction pressure (■) 3 and the first pressure reducing device 21. Intermediate pressure P- (Pd>P->P-) determined by the throttle amount of each second pressure reducing device 23
The liquid phase refrigerant and the gas phase refrigerant are mixed in the receiver 22 depending on the degree of freshness of the refrigerant.

When frost adheres and accumulates on the outdoor heat exchanger 5 and the defrost control unit 30 detects this, the defrost control unit 30 transmits a defrost start command signal and activates an electromagnetic valve driving means 31 such as a solenoid. The solenoid valve 8 is opened via the solenoid valve 8.

Further, the first pressure reducing device 21 is closed via the same first pressure reducing device control means 32. Further, the second pressure reducing device r? , 23 to the set aperture degree.

Since the solenoid valve 8 is opened, the refrigerant compressed by the compressor 1 and brought to a high pressure and high temperature is transferred to the bypass pipe 7. Solenoid valve 89 confluence part 1
5 and enters the outdoor heat exchanger 5, where the heat is radiated to melt and remove frost adhering to the outdoor heat exchanger 5. On the other hand, since the first pressure reducing device 2 is chained, the flow of refrigerant from the indoor heat exchanger 3 to the receiver 22 is stopped, but the pressure P in the receiver 22 during the heating operation is lowered during the defrosting operation. [self-flow part] 5 pressure P.

(Pe > Pe), the refrigerant in the receiver 22 flows into the outdoor heat exchanger 5 through the second pressure reducing device a23. The pressure inside the receiver 22, P, gradually decreases due to the outflow of the refrigerant, and finally, p, = l). bawl. At this time, by setting the effective internal volume of the receiver 22 to an appropriate value in consideration of the refrigerant specific volume due to the pressure difference between P- and Pe at this time, the amount of liquid phase refrigerant accumulated in the accumulator 6 is limited. be able to.

As described above, during defrosting operation, it is possible to prevent excessive liquid phase refrigerant from accumulating in the accumulator 6 and causing damage to the compressor 1 due to liquid compression operation, and to ensure that an appropriate amount of refrigerant is circulated. 7. Figure 2 is a refrigerant circuit diagram of an air conditioner according to a second embodiment. In Japan, 24 is a pore part such as a capillary tube or an orifice that creates resistance to the passage of the refrigerant.
The pore portion 24 is provided in place of the pressure reducing device 23, and the second pressure reducing device control means 33 is omitted as unnecessary. In the second embodiment, during heating operation, only the first pressure reducing device 21 adjusts the refrigerant flow rate to 1!1. This point is almost the same as the conventional example shown in the fifth section. However, similar to the first embodiment,
An intermediate pressure P is generated between the first pressure reducing device 2] and the pore portion 23, and since the receiver 22 is provided in this portion, the solenoid valve 8 is opened for defrosting operation, and the first pressure reducing device ;γ-2
1 becomes idle, the refrigerant stored in the receiver 22 gradually enters the outdoor heat exchanger 5 through the pores 24 and is replenished into the accumulator. As a result, the compressor 1
It is possible to prevent liquid compression and complete defrosting in a short time.

FIG. 3 is a refrigerant circuit diagram of an air conditioner according to a third embodiment. In Japan, 25 is four-way valve 2 and accumulator 6
The suction heat exchanger 25 is installed in the circuit between the receiver 22 and the receiver 22.
The rest is the same as the first embodiment except that heat is exchanged with the refrigerant inside.

The fourth UA is a Mollier diagram of the refrigerant in the third embodiment. The horizontal axis is specific enthalpy h, and the 41st axis is pressure P. Refrigerant pump cycle 1 is shown. Point A indicates high-pressure, high-temperature gas phase refrigerant compressed with a compression allowance of 1, and the indoor heat exchanger 3
It radiates heat and condenses to reach point B. Next, the pressure is reduced by the first pressure reducing device 21 and flows into the receiver 22 at six points. Here, the suction heat exchanger 25 exchanges (radiates) heat with the low-temperature refrigerant just before entering the accumulator 6, and the receiver 22
The refrigerant inside completely liquefies (point D). Next, the pressure is reduced by the second pressure reducing device 23 to reach point E. Next, outdoor heat exchanger 5
It passes through and absorbs heat from the outside air, reaching point F. Next, the refrigerant passes through the suction heat exchanger 25 and absorbs heat from the refrigerant in the receiver 22, reaching point G. This is compressed by the pressure wI machine 1 to reach point A, and in the one-intake heat exchanger 25 forming a cycle, heat vQ is exchanged between C-D and F-0.

In the third embodiment, L"J
) < 22 Release of refrigerant in,! 8 liquefaction and acuno,
Since there is endothermic vaporization of the refrigerant returning to the rotor 6, the f'lE dynamic coefficient and efficiency of the cycle are improved and liquid compression in the compressor can also be prevented.

In addition, in the third embodiment, the second pressure reducing device 23 is replaced by the second ['
It is also possible to adopt a configuration in which the second pressure reducing device control means 33 is omitted, with the pore portion 24 of II.

Also, the fruit hi of -1-! In example i, the first pressure reducing device 2 is equipped with the function of all the pipes, but it may also be a combination of a conventional pressure reducing device and an open field valve installed in series, and the first opening valve is provided with the defrost control section 30. The rice fields should be opened according to the instructions given by the government.

[Effect 1 of the Invention As described above, according to the present invention, the first pressure reducing device is sequentially provided between the indoor heat exchanger and the outdoor heat exchanger.

Since a receiver and a second pressure reducing device are installed, during defrosting operation, just by shutting down the first pressure reducing device, it is possible to feed the appropriate amount of refrigerant into one mulleter, reducing the time required for defrosting. , the effect of stopping the liquid compression in the compressor is (
°) be done.

[Brief explanation of the drawing]

11A to 11 show embodiments of the present invention, and the first
The figure shows a refrigerant circuit diagram of an air conditioner according to the first embodiment;
The figure is a refrigerant circuit diagram of an air conditioner according to the second embodiment;
1A is a refrigerant circuit diagram of an air conditioner according to a third embodiment, and FIG. 4 is a cycle diagram of the refrigerant circuit shown in FIG. 3. FIG. 5 is a refrigerant circuit diagram of a conventional air conditioner, and FIG. 6 is a sectional view of an accumulator. [In m, 1 is a compressor, 2 is a four-way valve, 3 is an indoor heat exchanger, 5 is an outdoor heat exchanger, 6 is an accumulator, 7 is a bypass pipe, 8 is a solenoid valve, 21 is a first pressure reducing device, 22 is a receiver, 23 is a second pressure reducing device, 24 is a pore section, 25 is an intake heat exchanger, and 30 is a defrosting control section. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (4)

[Claims] (1) An air conditioning circuit in which a compressor circulates refrigerant to an indoor heat exchanger and an outdoor heat exchanger via a four-way valve, and a bypass pipe having a solenoid valve transfers the refrigerant discharged from the compressor to the outdoor heat In an air conditioner having a defrosting circuit that defrosts the air by circulating the air through an exchanger, a first pressure reducing device and a receiver are sequentially connected to a pipe line from the indoor heat exchanger to the outdoor heat exchanger in the heating and cooling circuit. and a second pressure reducing device, the solenoid valve is opened in response to a defrosting start signal from the defrosting control section, the first pressure reducing device is closed, and the solenoid valve is closed in response to a defrosting end signal from the defrosting control section. An air conditioner characterized in that the valve is closed and the first pressure reducing device is controlled to have a predetermined degree of restriction. (2) The second pressure reducing device is a pressure reducing device that is controlled to a degree of aperture set by a defrosting start signal and a defrosting end signal from the defrosting control section, respectively. air conditioner. (3) The air conditioner according to claim 1, wherein the second pressure reducing device is a pore portion. (4) Any one of claims 1 to 3, wherein the receiver is provided with a suction heat exchanger that exchanges heat with the refrigerant between the four-way valve and the suction port of the compressor. Air conditioner described in.