KR20080006055A - Air conditioning system - Google Patents

Abstract

An air conditioning system is provided to perform a defrosting operation without stopping a heating operation when defrosting of an outdoor heat exchanger is required, thereby preventing reduction of heating performance. An air conditioning system(10) includes at least two compressors(11,12), an indoor heat exchanger(14), an expansion valve(15), an outdoor exchanger(16), and a 4-way valve(13). The compressors compress a refrigerant. The indoor exchanger performs heat exchange between the refrigerant passed through the compressors and indoor air. The expansion valve throttles the refrigerant passed through the indoor exchanger into low temperature and pressure. The 4-way valve switches the flow direction of the refrigerant for cooling or heating operation. The whole or some of the refrigerant discharged from any one compressor are branched off along a bypass pipeline and combined with the refrigerant passed through the expansion valve.

Description

Air conditioning system

1 is a diagram showing an air conditioning system having a defrost function according to a first embodiment of the present invention.

Figure 2 is a P-H diagram showing the state of the refrigerant when driving the defrosting system according to the first embodiment of the present invention.

Figure 3 is an air conditioning system with a defrosting function according to a second embodiment of the present invention.

Figure 4 is a P-H diagram showing the state of the refrigerant when driving the defrosting system according to a second embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

10: air conditioning system 11: main compressor

12: sub compressor 13: four-way valve

14: indoor heat exchanger 15: expansion valve

16: outdoor heat exchanger 17: gas-liquid separator

18: first valve 19: second valve

The present invention relates to an air conditioner, and more particularly, to an air conditioning system for preventing frost from forming on the surface of an outdoor heat exchanger when the air conditioner is operated in a heating mode as a heat pump.

In general, an air conditioner is a home appliance that exchanges indoor air with a refrigerant having a low temperature or high temperature to be changed into a high temperature or low temperature state and then discharged back to the room, thereby maintaining the indoor state in a cooling state or a heating state.

In detail, an air conditioner for heating and cooling purposes includes an indoor heat exchanger for exchanging indoor air and a refrigerant, an outdoor heat exchanger for exchanging outdoor air and a refrigerant, an compressor for compressing the refrigerant at high temperature and high pressure, and an expansion valve for expanding the refrigerant at low temperature and low pressure. It is composed. In addition, in the case of a combined cooling and heating system, a four-way valve is installed to reverse the circulation of the refrigerant, so that the functions of the indoor heat exchanger and the outdoor heat exchanger are switched. In other words, in the cooling mode, the outdoor heat exchanger performs the function of the condenser, and in the heating mode, the outdoor heat exchanger performs the function of the evaporator.

More specifically, in the cooling mode, the refrigerant in the high temperature and high pressure is introduced into the outdoor heat exchanger, and in the heating mode, the refrigerant in the low temperature and low pressure is introduced into the outdoor heat exchanger.

On the other hand, the heating operation is performed in winter, and the outdoor heat exchanger through which the refrigerant in a low temperature low pressure state flows is exposed to the outdoor where the temperature is low. Therefore, moisture is agglomerated on the surface of the outdoor heat exchanger during the heating operation, and the aggregated moisture is frozen to form frost.

In detail, when frost is formed on the surface of the outdoor heat exchanger, heat exchange between the refrigerant and outdoor air may not be performed smoothly. As a result, the temperature of the refrigerant flowing into the compressor inlet is lowered, thereby lowering the compression efficiency, and as a result, the overall heating efficiency is lowered, and consumers are dissatisfied.

Due to these problems, much research and development has been made on the defrosting method of the outdoor heat exchanger. For example, when the surface of the outdoor heat exchanger freezes, the heating operation is stopped for a predetermined time, and the reverse cycle (cooling operation) using the four sides is performed to defrost the outdoor heat exchanger.

Alternatively, a hot gas bypass may be applied in which the refrigerant discharged from the compressor is not directly transferred to the indoor heat exchanger but is immediately supplied to the outdoor heat exchanger.

However, all of the above methods have a common problem that the heating operation is not performed in the defrosting process. Therefore, while the defrosting process is performed, there is a disadvantage in that the room temperature decreases, and the problem of dissatisfaction of the consumer remains.

The present invention has been proposed to solve the above problems, an object of the present invention is to provide an air conditioning system that allows the defrosting process to be carried out without interruption of heating operation when the defrosting operation of the outdoor heat exchanger is required.

In detail, it is an object of the present invention to provide an air conditioning system in which a heating operation is continuously performed even in a process in which a defrosting operation is performed, thereby reducing consumer dissatisfaction and at the same time preventing heating performance from being lowered.

An air conditioning system according to the present invention for achieving the object as described above comprises at least two compressors for compressing a refrigerant; An indoor heat exchanger through which the refrigerant passing through the compressor exchanges heat with indoor air; An expansion valve in which the refrigerant passing through the indoor heat exchanger is throttled at low temperature and low pressure; The outdoor heat exchanger includes a heat exchanger in which the refrigerant passing through the expansion valve exchanges heat with outdoor air, and all or a part of the refrigerant discharged from any one of the compressors during the defrosting operation is branched along the bypass pipe, thereby passing through the expansion valve. It is characterized in that combined with.

In another aspect the air conditioning system according to the invention comprises a compressor; An indoor heat exchanger configured to condense refrigerant passing through the compressor; An expansion member to expand the refrigerant passing through the indoor heat exchanger; An outdoor heat exchanger through which the refrigerant passing through the expansion member is evaporated; a part of the refrigerant discharged from the compressor is always supplied to the indoor heat exchanger, and a part of the refrigerant discharged from the compressor is at least the indoor heat exchanger Bypassing to other places, characterized in that the heating function and the defrost function can be performed at the same time.

By the above configuration, since the heating operation is continuously performed even during the defrosting operation, there is an effect that the heating efficiency is improved and the consumer dissatisfaction is reduced.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the spirit of the present invention is not limited to the embodiments presented, and other embodiments included within the scope of the present invention and other degenerate inventions can be easily added by adding, changing, or deleting other elements. I can suggest.

Hereinafter, the refrigerant cycle when the heating operation is performed will be described as a basic embodiment.

1 is a diagram illustrating an air conditioning system having a defrost function according to a first embodiment of the present invention.

Referring to FIG. 1, an air conditioning system 10 having a defrost function according to the present invention includes a compressor for compressing a refrigerant at high temperature and high pressure, and an indoor heat exchanger for allowing the refrigerant compressed by the compressor to exchange heat with indoor air. 14, an expansion valve 15 through which the refrigerant passing through the indoor heat exchanger 14 is cooled to a low temperature and a low pressure, and an outdoor heat exchanger through which the refrigerant passing through the expansion valve 15 exchanges with outdoor air. 16) is included.

In detail, the compressor has a main compressor (11) for always supplying the refrigerant to the indoor heat exchanger (14) in both the heating operation and the defrost operation, so that all or part of the compressed refrigerant is supplied to the outdoor heat exchanger during the defrost operation. It consists of a sub-compressor 12. Then, the four-way valve 13 is mounted on the outlet side of the compressor, so that the flow direction of the refrigerant can be switched according to the cooling or heating mode. That is, the indoor heat exchanger 14 and the outdoor heat exchanger 16 selectively perform the function of the condenser or the evaporator according to the cooling mode or the heating mode. For example, in a cooling mode, an indoor heat exchanger performs the function of an evaporator, and an outdoor heat exchanger performs the function of a condenser. In the heating mode, the functions of the indoor heat exchanger and the outdoor heat exchanger are switched.

In addition, the outlet of the sub-compressor 12 is bifurcated so that all or part of the refrigerant discharged from the sub-compressor 12 is bypassed toward the outdoor heat exchanger 16. As a result, one of the branched pipes is connected to the four-way valve 13 inlet pipe and the other is connected to the outdoor heat exchanger 16 inlet pipe. The main compressor 11 outlet pipe is connected to the four-way valve 13, and at some point, the pipe connecting the sub-compressor 12 and the four-way valve 13 is combined.

In detail, the first valve 18 is mounted on one side of the pipe connecting the outlet of the sub-compressor 12 and the four-way valve 13. The second valve 19 is mounted on one side of the pipe connecting the sub compressor 12 and the outdoor heat exchanger 16 to the inlet pipe. A pressure regulator 20 is attached to the point passing through the second valve 19 so that the high pressure refrigerant discharged from the sub-compressor 12 and bypassed passes through the expansion valve 15. Make sure it is the same as

Here, the said 1st valve 18 and the 2nd valve 19 are all 2-way valves, and are valves which adjust the opening degree of piping.

In detail, in the case where all the refrigerant discharged from the sub-compressor 12 in the defrosting operation mode are used for defrosting purposes, the first valve 18 is completely opened in the heating operation state, and the second valve 19 is Make sure it closes completely. In the defrosting operation state, the first valve 18 is completely opened, and the second valve 19 is completely opened.

On the other hand, the first valve 18 may not be necessary in order to use only a part of the refrigerant discharged from the sub-compressor 12 in the defrosting operation. That is, the second valve 19 is completely closed in the heating operation mode, and the second valve 19 is opened in the defrost operation mode. Then, a part of the refrigerant discharged from the sub compressor 12 in the defrosting operation mode is moved to the indoor heat exchanger 14, and the other part is bypassed.

Accordingly, the number of mounting of the valves 18 and 19 can be properly adjusted according to the amount of refrigerant bypassed in the defrosting operation mode.

In addition, the pressure regulator 20 senses the pressure on the outlet side of the expansion valve 15, and controls the pressure so that the detected pressure and the pressure of the refrigerant bypassed from the sub-compressor 12 remain the same.

In addition, the inlet side of the compressor is equipped with a gas liquid (accumulator), the refrigerant passing through the outdoor heat exchanger 16 may be separated into a liquid and gas, so that only gas may be introduced into the compressor.

When the heating operation is started by the air conditioning system having the above configuration, the refrigerant is compressed to high temperature and high pressure by the sub-compressor 12 and the main compressor 11. In addition, the high temperature and high pressure refrigerant discharged from the compressors 11 and 12 is guided to the indoor heat exchanger 14 by the four-way valve 13. Here, during the heating operation, only the first valve 18 is opened so that all of the refrigerant discharged from the compressor is guided to the indoor heat exchanger 14. And, while passing through the indoor heat exchanger 14, the refrigerant is heat-exchanged with the indoor air, the room temperature is increased.

In addition, the refrigerant that has been heat-exchanged while passing through the indoor heat exchanger 14 and changed into a liquid phase is drawn out at a low temperature and low pressure while passing through the expansion valve 15. In addition, the refrigerant dropped to the low temperature and low pressure flows into the outdoor heat exchanger 16 to exchange heat with outdoor air. In detail, the refrigerant passing through the outdoor heat exchanger 16 absorbs heat from the outdoor air and changes to a gaseous state. The refrigerant changed into a gas state is guided to the compressors 11 and 12 by the four-way valve 13. At this time, when the gas-liquid separator 17 is mounted on the compressor inlet side, phase separation is performed such that only the gaseous refrigerant flows into the compressor inside the gas-liquid separator 17.

On the other hand, when the defrosting operation is started, all of the refrigerant compressed by the main compressor 11 is heated while forming a cycle along the same path as in the heating operation.

In addition, all or a part of the refrigerant compressed by the sub compressor 12 is bypassed and the pressure drops while passing through the pressure regulator 20. Then, the pressure lowered refrigerant is combined with the refrigerant passing through the expansion valve 15, so that only the temperature rises slightly.

Here, in the defrosting operation, the first valve 18 may be closed so that all of the refrigerant discharged from the sub-compressor 12 may be bypassed or only a portion of the refrigerant discharged from the sub-compressor 12 may be bypassed. have. The second valve 19 is opened in the defrosting process and closed in the heating operation. Therefore, in the heating operation, all of the refrigerant discharged from the sub-compressor 12 flows to the indoor heat exchanger 14. In the defrosting operation, all or part of the refrigerant discharged from the sub-compressor 12 passes to the indoor heat exchanger 14. Flows).

In this case, when only a part of the refrigerant discharged from the sub-compressor 12 is bypassed, the first valve 18 may not be mounted.

In detail, since a part of the compressed refrigerant is bypassed in the defrosting operation, the amount of the refrigerant flowing into the indoor unit is less than that of the heating operation. Therefore, the pressure drop width of the refrigerant decreases while passing through the expansion valve 15. In addition, the refrigerant temperature at the inlet of the outdoor heat exchanger 16 is increased by the refrigerant bypassed from the sub-compressor 12. Therefore, since the refrigerant temperature at the inlet side of the outdoor heat exchanger 16 is increased, the frost aggregated on the surface of the pipe of the outdoor heat exchanger 16 is melted and defrosted.

2 is a P-H diagram showing a state of a refrigerant when the defrosting system is driven according to the first embodiment of the present invention.

Referring to FIG. 2, assuming that the heating operation cycle and the defrost operation cycle are ideally performed, the state of the refrigerant changes along the a-b-c-d line in the heating operation process, and changes along the g-c-e-f line in the defrosting operation process.

That is, in the heating operation process, the compressor outlet pressure becomes P1 and the expansion valve outlet pressure becomes P2.

On the other hand, when the defrosting operation cycle is performed, the refrigerant is compressed to high pressure P1 while passing through the compressor, but since a part of the compressed refrigerant is bypassed, the pressure of the refrigerant becomes P3 while passing through the expansion valve 15. In addition, while the bypassed refrigerant meets the refrigerant at the outlet of the expansion valve 15, the pressure is kept constant at P3 and only the refrigerant temperature is increased. Therefore, the inlet temperature of the outdoor heat exchanger 16 is higher than during the heating operation, so that frost attached to the surface of the outdoor heat exchanger 16 is removed. Here, the compressor outlet refrigerant bypassed does not substantially affect the compressor inlet portion, and there is no difference in the amount of the refrigerant flowing into the compressor and the refrigerant discharged. Accordingly, it can be seen that there is no change in the compressor outlet pressure, but only a portion of the refrigerant is bypassed without flowing to the indoor heat exchanger 14, so that the amount of heat exchange with the indoor air is reduced.

3 is a diagram showing an air conditioner system having a defrost function according to a second embodiment of the present invention.

Referring to FIG. 3, the air conditioning system according to the present embodiment has the same components as those of the first embodiment, but the refrigerant bypassed from the sub-compressor 12 is the outdoor heat exchanger 16. There is a difference in guiding towards the exit. In other words, in the first embodiment, the bypassed refrigerant is guided toward the inlet of the outdoor heat exchanger 16, but in the second embodiment, the refrigerant is guided toward the outlet of the outdoor heat exchanger 16.

Hereinafter, a description of the same components and functions presented in the first embodiment will be omitted.

In detail, the refrigerant discharged from the sub compressor 12 is bypassed toward the outlet of the outdoor heat exchanger 16 by opening the first valve 19 and closing the first valve 18. The bypassed high temperature and high pressure refrigerant is controlled to be equal to the pressure of the refrigerant passing through the outdoor heat exchanger 16 by the action of the pressure regulator 20. Then, the bypassed refrigerant and the refrigerant passing through the outdoor heat exchanger 16 meet to increase the temperature. Here, since some of the high temperature and high pressure refrigerant passing through the compressor is bypassed, as described in the first embodiment, the pressure of the refrigerant passing through the expansion valve 15 is maintained to be higher than the pressure in the heating operation. do.

Meanwhile, the refrigerant combined at the outlet of the outdoor heat exchanger 16 is guided to the compressor inlet by the four-way valve 13. Then, since the temperature of the refrigerant guided toward the compressor inlet becomes higher than the temperature at the time of heating operation, the pressure of the refrigerant after compression is also slightly increased. In addition, since the refrigerant pressure increases after compression, the temperature and pressure of the refrigerant passing through the expansion valve 15 also increase, and as a result, the refrigerant temperature at the inlet side of the outdoor heat exchanger 16 increases. Thus, the defrosting process of the outdoor heat exchanger 16 is performed. In addition, since the temperature at the inlet side of the outdoor heat exchanger 16 is increased, there is also an effect of delaying the defrosting time.

4 is a P-H diagram showing a state of a refrigerant when the defrosting system is driven according to the second embodiment of the present invention.

Referring to FIG. 4, in a normal heating operation, the refrigerant is changed along a-b-c-d, and in the defrosting operation, it is changed along i-j-k-h.

In detail, a part of the refrigerant discharged from the compressor is bypassed and guided to the outlet side of the outdoor heat exchanger 16, that is, the inlet side of the compressor. Then, the refrigerant that is not bypassed flows in all directions and flows into the indoor heat exchanger 14. Then, it passes through the expansion valve 15 and expands in a state higher than the expansion pressure and temperature during the heating operation. That is, the pressure of the refrigerant passing through the compressor rises from P1 to P5, and the pressure of the refrigerant passing through the expansion valve 15 rises from P2 to P4. As a result, the temperature of the refrigerant introduced into the outdoor heat exchanger 16 is increased, and defrosting of the outdoor heat exchanger 16 is performed. In addition, the temperature of the refrigerant passing through the outdoor heat exchanger 16 through the defrosting process is lowered, and the temperature of the refrigerant passing through the refrigerant is increased again to increase the compressor inlet temperature.

From the P-H diagram presented, it can be seen that the defrost cycle rises to the upper right side as compared with the cycle during the heating operation.

By the defrosting system as in the above-described embodiments, the defrosting operation is performed together while the heating operation is continuously performed, thereby preventing a sudden decrease in the heating efficiency, thereby eliminating consumer complaints.

In addition, as an exemplary embodiment of the present invention except that the refrigerant discharged from any one compressor using two or more compressors is bypassed for defrosting, one compressor is used, and only a part of the refrigerant discharged by the valve is bypassed. can do. That is, some of the refrigerant discharged from the compressor may be bypassed to be connected to the inlet or outlet of the outdoor heat exchanger. Only the difference in the amount of refrigerant will have the same effect as the case of using a plurality of compressors, it will be apparent that the same effect can be obtained by increasing the capacity of the compressor.

By the air conditioning system according to the present invention having the above configuration, the heating operation is continuously performed in the process of the defrosting operation, thereby reducing the dissatisfaction of the consumer.

In addition, since the heating operation is not interrupted during the defrosting operation, the phenomenon in which the room temperature is rapidly reduced is eliminated, thereby improving the heating efficiency.

In addition, if the temperature sensor for detecting the pipe temperature of the outdoor heat exchanger is mounted during the heating operation is performed, if it is determined that the freezing temperature by the temperature sensor, the defrosting operation according to the invention before the heat exchanger is frozen. As a result, the phenomenon in which the outdoor heat exchanger freezes can be prevented in advance.

Claims (15)

At least two compressors for compressing the refrigerant; An indoor heat exchanger through which the refrigerant passing through the compressor exchanges heat with indoor air; An expansion valve in which the refrigerant passing through the indoor heat exchanger is throttled at low temperature and low pressure; Includes an outdoor heat exchanger in which the refrigerant passing through the expansion valve heat exchange with the outdoor air, All or part of the refrigerant discharged from any one of the compressor during the defrosting operation is branched along the bypass pipe, the air conditioning system, characterized in that to be combined with at least the refrigerant passing through the expansion valve. The method of claim 1, Air conditioning system further comprises a four-way valve for redirecting the flow of refrigerant to enable cooling or heating operation. The method of claim 1, And the bypass pipe line is connected to an inlet side of the outdoor heat exchanger. The method of claim 1, And the bypass pipe line is connected to an outlet side of the outdoor heat exchanger. The method of claim 1, All of the refrigerant discharged from at least one of the compressors flows to the indoor heat exchanger regardless of the heating operation or the defrosting operation. The method of claim 1, And a valve mounted at least in the bypass conduit to allow the bypass of the refrigerant to be adjusted in accordance with the heating operation or the defrosting operation mode. The method of claim 1, And a pressure regulating device for maintaining the pressure of the bypassed refrigerant to be the same as the pressure of the refrigerant passing through the expansion valve. The method of claim 1, And the temperature of the outdoor heat exchanger is increased by the refrigerant flowing along the bypass pipe, so that the heating operation is continued even during the defrosting operation. compressor; An indoor heat exchanger configured to condense refrigerant passing through the compressor; An expansion member to expand the refrigerant passing through the indoor heat exchanger; And an outdoor heat exchanger through which the refrigerant passing through the expansion member is evaporated. A part of the refrigerant discharged from the compressor is always supplied to the indoor heat exchanger, and the remaining part of the refrigerant discharged from the compressor is bypassed at least outside the indoor heat exchanger, so that the heating function and the defrost function can be simultaneously performed. Air conditioning system. The method of claim 9, The bypassed refrigerant is combined with the refrigerant passing through the expansion member and introduced into the indoor heat exchanger. The method of claim 9, The bypassed refrigerant is combined with the refrigerant passing through the indoor heat exchanger and introduced into the compressor. The method of claim 9, A valve mounted on a flow path of the bypassed refrigerant, the valve being closed during a heating operation and opened during a defrost operation; And a pressure regulator mounted on the outlet side of the valve. The method of claim 9, The compressor may include at least one main compressor into which the discharged refrigerant is always introduced into the indoor heat exchanger; A part of the refrigerant discharged is connected to an outlet side of the main compressor and flows into an indoor heat exchanger, and the other part is bypassed and includes at least one sub-compressor introduced into a place other than the indoor heat exchanger. The method of claim 13, A first valve installed on a flow path of the refrigerant flowing from the sub-compressor toward the compressor outlet, always open when heated and selectively open when defrosted; And a second valve installed on the flow path of the refrigerant bypassed from the sub-compressor and opened only during the defrosting process. The method of claim 9, And the temperature of the indoor heat exchanger is increased by the refrigerant flowing by bypassing the indoor heat exchanger.

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