Air conditioner

An air conditioner including a compressor, an outdoor heat exchanger, an indoor heat exchanger, a switching valve for guiding refrigerant discharged from the compressor to the outdoor heat exchanger during a cooling operation and to the indoor heat exchanger during a heating operation, and an injection module for injecting a portion of the refrigerant discharged from the indoor heat exchanger to the compressor, performing heat exchange between a portion of the refrigerant discharged from the indoor heat exchanger and the refrigerant that moves from the outdoor heat exchanger to the indoor heat exchanger during the cooling operation, and injecting the refrigerant into the compressor.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Korean Patent Application No. 10-2016-0006092, filed on Jan. 18, 2016, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

Generally, an air conditioner is an apparatus that cools or heats a room using a refrigeration cycle, which includes a compressor, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger. The air conditioner may be configured as a cooler to cool a room, a heater to heat a room, or a combined cooling/heating air conditioner, which selectively cools or heats a room.

The combined cooling/heating air conditioner generally includes a 4-way valve, which changes the path of refrigerant, compressed in the compressor, based on a cooling operation and a heating operation. During a cooling operation, the refrigerant, compressed in the compressor, flows to the outdoor heat exchanger by passing through the 4-way valve, and the outdoor heat exchanger serves as a condenser. Then, the refrigerant, condensed in the outdoor heat exchanger, is expanded in the expansion valve, and thereafter introduced into the indoor heat exchanger. At this time, the indoor heat exchanger serves as an evaporator, and in turn, the refrigerant evaporated in the indoor heat exchanger again passes through the 4-way valve to be introduced into the compressor.

During the cooling operation or the heating operation, refrigerant in the compressor may improve the coefficient of performance of a system.

However, the conventional technology of injecting the refrigerant into the compressor during the cooling operation includes bypassing a portion of the high-temperature and high-pressure liquid-phase refrigerant, having passed through the condenser, thus causing deterioration in the cooling ability of an indoor unit due to a reduction in the evaporation flow rate of the refrigerant.

SUMMARY OF THE INVENTION

In view of the foregoing, in accordance with one embodiment of the present invention, there is provided an air conditioner including a compressor for compressing refrigerant, an outdoor heat exchanger installed in an outdoor space for performing heat exchange between the refrigerant and outdoor air, an indoor heat exchanger installed in an indoor space for performing heat exchange between the refrigerant and indoor air, a switching valve for guiding the refrigerant, discharged from the compressor, to the outdoor heat exchanger during a cooling operation and to the indoor heat exchanger during a heating operation, and an injection module for injecting a portion of the refrigerant, discharged from the indoor heat exchanger, to the compressor, wherein the injection module performs heat exchange between the portion of the refrigerant discharged from the indoor heat exchanger and refrigerant, which moves from the outdoor heat exchanger to the indoor heat exchanger, during the cooling operation, and injects the heat-exchanged refrigerant into the compressor, thus increasing efficiency.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Advantages and features of the present invention and methods for achieving those of the present invention will become apparent upon referring to embodiments described later in detail with reference to the attached drawings. However, embodiments are not limited to the embodiments disclosed hereinafter and may be embodied in different ways. The embodiments are provided for perfection of disclosure and for informing persons skilled in this field of art of the scope of the present invention. The same reference numerals may refer to the same elements throughout the specification.

Spatially-relative terms such as “below”, “beneath”, “lower”, “above”, or “upper” may be used herein to describe one element's relationship to another element as illustrated in the Figures. It will be understood that spatially-relative terms are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. For example, if the device in one of the figures is turned over, elements described as “below” or “beneath” other elements would then be oriented “above” the other elements. The exemplary terms “below” or “beneath” can, therefore, encompass both an orientation of above and below. Since the device may be oriented in another direction, the spatially-relative terms may be interpreted in accordance with the orientation of the device.

In the drawings, the thickness or size of each layer is exaggerated, omitted, or schematically illustrated for convenience of description and clarity. Also, the size or area of each constituent element does not entirely reflect the actual size thereof.

FIG. 1is a schematic circuit diagram illustrating the refrigerant cycle of an air conditioner in accordance with one embodiment of the present invention.FIG. 2is a view illustrating an injection heat exchanger of the air conditioner in accordance with one embodiment of the present invention.

Referring toFIGS. 1 and 2, the air conditioner100may include a compressor110for compressing refrigerant, an outdoor heat exchanger120installed in an outdoor space for performing heat exchange between the refrigerant and outdoor air, an indoor heat exchanger130installed in an indoor space for performing heat exchange between the refrigerant and indoor air, a switching valve180for guiding the refrigerant discharged from the compressor110to the outdoor heat exchanger120during a cooling operation and to the indoor heat exchanger130during a heating operation, and an injection module for injecting a portion of the refrigerant discharged from the indoor heat exchanger130to the compressor110.

The air conditioner100may further include a gas-liquid separator140for separating the refrigerant into liquid-phase refrigerant and gas-phase refrigerant.

The air conditioner100may include an outdoor unit and an indoor unit that are connected to each other. The outdoor unit may be installed in an outdoor space and the indoor unit installed in an indoor space.

The outdoor unit may include the compressor110, the outdoor heat exchanger120, an outdoor expansion valve150, the injection module, and the gas-liquid separator140.

The indoor unit may include the indoor heat exchanger130and an indoor expansion valve160.

The compressor110may be installed in the outdoor unit, and compress low-temperature and low-pressure refrigerant that is introduced into high-temperature and high-pressure refrigerant.

The compressor110may have any of a variety of configurations. For example, the compressor110may include a reciprocation compressor using a cylinder and a piston, a scroll compressor using a pivotable scroll and a fixed scroll, or an inverter compressor for adjusting the compression of refrigerant based on an operational frequency.

One compressor110or a plurality of compressors110may be provided in some embodiments. In the present embodiment, two compressors110are provided.

The compressor110is connected to the switching valve180, the gas-liquid separator140, and the injection module. The compressor110may include an inlet port111, into which refrigerant evaporated in the indoor heat exchanger130is introduced during a cooling operation, or into which refrigerant evaporated in the outdoor heat exchanger120is introduced during a heating operation, an injection port112, into which relatively low pressure refrigerant, evaporated in the injection module via heat exchange, is injected, and an outlet port113, from which the compressed refrigerant is discharged.

For example, as shown, the compressor110includes the inlet port111into which the refrigerant evaporated in the evaporators120and130is introduced, the injection port112, into which relatively low pressure refrigerant, evaporated in the injection module via heat exchange, is provided, and the outlet port113, from which the compressed refrigerant is discharged to the condensers120and130by passing through the switching valve180.

The compressor110may compress the refrigerant, introduced through the inlet port111, in a compression chamber, and combine the refrigerant, introduced through the injection port112, with the refrigerant introduced through the inlet port111, while compressing the refrigerant introduced through the inlet port111. The compressor110may compress the combined refrigerant and discharges together through the outlet port113. The refrigerant discharged from the outlet port113then flows to the switching valve180.

The switching valve180may serve as a path switching valve180for switching between cooling and heating, and guide the refrigerant compressed in the compressor110to the outdoor heat exchanger120during a cooling operation and to the indoor heat exchanger130during a heating operation.

The switching valve180may be connected to the outlet port113of the compressor110and to the gas-liquid separator140. The switching valve180may also be connected to the indoor heat exchanger130and the outdoor heat exchanger120.

During a cooling operation, for example, the switching valve180interconnects the outlet port113of the compressor110and the outdoor heat exchanger120, and interconnects the indoor heat exchanger130and the gas-liquid separator140, or the indoor heat exchanger130and the inlet port111of the compressor110.

During a heating operation, for example, the switching valve180interconnects the outlet port113of the compressor110and the indoor heat exchanger130, and interconnects the outdoor heat exchanger120and the gas-liquid separator140, or the outdoor heat exchanger120and the inlet port111of the compressor110.

Although the switching valve180may be implemented in various modules capable of interconnecting different flow-paths, in the present embodiment, for example, the switching valve180is a 4-way valve. However, in some embodiments, the switching valve180may be any of a variety of valve types or a combination thereof, such as a combination of two 3-way valves.

The outdoor heat exchanger120is installed in the outdoor unit, which is located in an outdoor space. The outdoor heat exchanger120performs heat exchange between the refrigerant passing therethrough and the outdoor air. The outdoor heat exchanger120operates as a condenser for condensing refrigerant during a cooling operation, and operates as an evaporator for evaporating refrigerant during a heating operation.

The outdoor heat exchanger120may be connected to the switching valve180and the outdoor expansion valve150.

During a cooling operation, for example, the refrigerant that has been compressed in the compressor110and has passed through the outlet port113of the compressor110and the switching valve180is introduced into the outdoor heat exchanger120so as to be condensed therein, and thereafter flows to the outdoor expansion valve150.

During a heating operation, for example, the refrigerant expanded in the outdoor expansion valve150flows to the outdoor heat exchanger120so as to be evaporated therein, and thereafter flows to the switching valve180.

The outdoor expansion valve150may be fully opened so that the refrigerant passes therethrough during a cooling operation. During a heating operation, the opening degree of the outdoor expansion valve150may be adjusted so as to expand the refrigerant during a heating operation.

The outdoor expansion valve150is provided between the outdoor heat exchanger120and an overcooling heat-exchange hub190. However, in some embodiments, the outdoor expansion valve150may be provided between the outdoor heat exchanger120and an injection heat exchanger17.

During a cooling operation, the outdoor expansion valve150passes the refrigerant introduced from the outdoor heat exchanger120, and guides the refrigerant to the overcooling heat-exchange hub190.

During a heating operation, the outdoor expansion valve150expands the refrigerant that has undergone heat exchange in the injection module and has passed through the overcooling heat-exchange hub190, and guides the expanded refrigerant to the outdoor heat exchanger120.

The indoor heat exchanger130is installed in the indoor unit, which is located in an indoor space, and performs heat exchange between the refrigerant passing therethrough and indoor air. The indoor heat exchanger130operates as an evaporator for evaporating refrigerant during a cooling operation, and operates as a condenser for condensing refrigerant during a heating operation.

The indoor heat exchanger130may be connected to the switching valve180and the indoor expansion valve160.

During a cooling operation, the refrigerant expanded in the indoor expansion valve160is introduced into the indoor heat exchanger130so as to be evaporated therein, and thereafter flows to the switching valve180.

During a heating operation, the refrigerant that has been compressed in the compressor110and has passed through the outlet port113of the compressor110and the switching valve180is introduced into the indoor heat exchanger130so as to be condensed therein, and thereafter flows to the indoor expansion valve160.

During a cooling operation, the opening degree of the indoor expansion valve160may be adjusted so as to expand the refrigerant. During a heating operation, the indoor expansion valve160may be completely opened to pass the refrigerant. The indoor expansion valve160may be provided between the indoor heat exchanger130and the injection heat exchanger17.

During a cooling operation, the indoor expansion valve160expands the refrigerant moved to the indoor heat exchanger130. During a heating operation, the indoor expansion valve160passes the refrigerant introduced from the indoor heat exchanger130, and guides the refrigerant to the injection heat exchanger17.

The gas-liquid separator140may be provided between the compressor110and the switching valve180, and separates the refrigerant into liquid-phase refrigerant and gas-phase refrigerant. For example, as shown, the gas-liquid separator140is provided between the switching valve180and the inlet port111of the compressor110.

The gas-liquid separator140may be connected to the switching valve180and the inlet port111of the compressor110. For example, as shown, the gas-liquid separator140is located in an inlet pipe114, which is connected to the indoor heat exchanger130and the inlet port111of the compressor110. More specifically, the gas-liquid separator140is located in the inlet pipe114between the inlet port111of the compressor110and the switching valve180.

The gas-liquid separator140separates the refrigerant evaporated in the indoor heat exchanger130during a cooling operation, or the refrigerant evaporated in the outdoor heat exchanger120during a heating operation, into liquid-phase refrigerant and gas-phase refrigerant, and guides the gas-phase refrigerant to the inlet port111of the compressor110. Specifically, for example, the gas-liquid separator140separates the refrigerant evaporated in the evaporators120and130into gas-phase refrigerant and liquid-phase refrigerant and guides the gas-phase refrigerant to the inlet port111of the compressor110.

The refrigerant evaporated in the outdoor heat exchanger120or the indoor heat exchanger130may be introduced into the gas-liquid separator140by way of the switching valve180. Accordingly, for example, the gas-liquid separator140may maintain a temperature of approximately 0˜5° C., and may radiate cold energy to the outside. The temperature of the surface of the gas-liquid separator140is lower than the temperature of the refrigerant condensed in the outdoor heat exchanger120during a cooling operation. The gas-liquid separator140may have a longitudinally elongated cylindrical shape (not limited thereto).

A gas-liquid separator jacket200is provided so as to surround the surface of the gas-liquid separator140. The gas-liquid separator jacket200may be in thermal contact with the surface of the gas-liquid separator140. The gas-liquid separator jacket200is preferably formed of a material having high thermal conductivity to perform heat exchange between the gas-liquid separator140and brine.

In detail, for example, the gas-liquid separator jacket200is installed so that the inner circumferential surface thereof contacts the outer circumferential surface of the gas-liquid separator140. The gas-liquid separator jacket200may be formed so as to correspond to the length of the gas-liquid separator140in order to facilitate heat exchange between the gas-liquid separator140and brine.

The gas-liquid separator jacket200may be connected to the overcooling heat-exchange hub190, a circulation pump191, and the gas-liquid separator140. The brine for undergoing heat exchange with the gas-liquid separator140flows inside the gas-liquid separator jacket200. The gas-liquid separator jacket200may include a flow path (not illustrated) for moving the brine along the surface of the gas-liquid separator140. Accordingly, the brine, introduced from the overcooling heat-exchange hub190into the gas-liquid separator jacket200by the driving of the circulation pump191, undergoes heat exchange with the gas-liquid separator140while moving along the surface of the gas-liquid separator140. The brine that has undergone heat exchange with the gas-liquid separator140is then introduced into the overcooling heat-exchange hub190.

The overcooling heat-exchange hub190may be provided between the indoor heat exchanger130and the outdoor heat exchanger120. The overcooling heat-exchange hub190may be connected to the gas-liquid separator jacket200, the injection heat exchanger17, the circulation pump191, and the outdoor expansion valve150. Accordingly, the brine that has absorbed cold energy radiated from the gas-liquid separator140may be stored inside the overcooling heat-exchange hub190. Also, because the overcooling heat-exchange hub190is connected to the circulation pump191, the brine stored in the overcooling heat-exchange hub190may be forcibly moved to the gas-liquid separator jacket200.

The overcooling heat-exchange hub190may accommodate a pipe installed therein for the flow of the refrigerant that has been condensed in the outdoor heat exchanger120during a cooling operation and has passed through the outdoor expansion valve150. Accordingly, with such configuration, heat exchange between the brine and the refrigerant condensed in the outdoor heat exchanger120occurs inside the overcooling heat-exchange hub190during a cooling operation. At this time, the temperature of the brine is lower than the temperature of the refrigerant condensed in the outdoor heat exchanger120. Thereby, the temperature of the brine is raised and the temperature of the condensed refrigerant is lowered, whereby overcooling occurs.

The pipe, which is installed inside the overcooling heat-exchange hub190for the movement of the refrigerant, may extend in a zigzag shape. As such, the heat exchange process between the brine and the refrigerant inside the overcooling heat-exchange hub190may be extended. It is understood that the overcooling heat-exchange hub190may be as large as possible in order to store as much brine as possible.

The circulation pump191operates to forcibly circulate the brine, which flows through the overcooling heat-exchange hub190and the gas-liquid separator jacket200.

During a cooling operation, for example, the circulation pump191is driven to forcibly circulate the brine, thereby allowing the brine, which has undergone heat exchange with the gas-liquid separator140, to be stored in the overcooling heat-exchange hub190.

During a heating operation, for example, the circulation pump191is not driven, and thus cannot forcibly circulate the brine. However, even when the circulation pump191is not driven during a heating operation, natural circulation of the brine may occur via convection, which may cause the brine to move to the gas-liquid separator jacket200so as to undergo heat exchange with the gas-liquid separator140.

The circulation pump191may be provided between the overcooling heat-exchange hub190and the gas-liquid separator jacket200. For example, the circulation pump191may be a general pump and may be provided in a plural number in order to increase the forcible circulation of the brine. A shutoff valve (not illustrated) may be installed between the gas-liquid separator jacket200and the overcooling heat-exchange hub190for stopping the movement of the brine. During a heating operation, the shutoff valve may be closed to prevent the movement of the brine by natural circulation. However, during a cooling operation, the shutoff valve must be open because the circulation pump191is driven.

The injection module injects at least a portion of the refrigerant discharged from the indoor heat exchanger130to the compressor110.

During a cooling operation, the injection module performs heat exchange between at least a portion of the refrigerant discharged from the indoor heat exchanger130and the refrigerant, which flows from the outdoor heat exchanger120to the indoor heat exchanger130, and injects the refrigerant to the compressor110.

Specifically, for example, during a cooling operation, the injection module performs heat exchange between a portion of the low-temperature and low-pressure refrigerant, which has undergone heat exchange with indoor air in the indoor heat exchanger130, but has not yet been introduced into the compressor110, and the high-temperature and high-pressure refrigerant condensed in the outdoor heat exchanger120, thereby generating medium-temperature and medium-pressure refrigerant. The medium-temperature and medium-pressure refrigerant described above is then injected into the compressor110. Accordingly, a portion of the refrigerant, which has already undergone heat exchange with outdoor air in the indoor heat exchanger130, is injected into the compressor110during a cooling operation, which results in increased efficiency.

In addition, during a heating operation, the injection module injects at least a portion of the refrigerant, which flows from the indoor heat exchanger130to the outdoor heat exchanger120, to the compressor110. Specifically, for example, during a heating operation, the injection module diverts and expands a portion of the refrigerant, which has completely undergone heat exchange with indoor air in the indoor heat exchanger130to thereby move from the indoor heat exchanger130to the outdoor heat exchanger120, and performs heat exchange between the expanded refrigerant and a remaining portion of the refrigerant, which flows from the indoor heat exchanger130to the outdoor heat exchanger120. A portion of the heat-exchanged refrigerant, which flows from the indoor heat exchanger130to the outdoor heat exchanger120, is then injected into the compressor110.

Hereinafter, the detailed configuration of the injection module will be described.

The injection module may include the injection heat exchanger17and a first injection expansion valve176. The injection heat exchanger17performs heat exchange between the refrigerant discharged from the indoor heat exchanger130and the refrigerant, which flows from the outdoor heat exchanger120to the indoor heat exchanger130, during a cooling operation. The first injection expansion valve176expands the refrigerant, which flows between the injection heat exchanger17and the compressor110.

During a cooling operation, the injection heat exchanger17may perform heat exchange between the refrigerant discharged from the indoor heat exchanger130and the refrigerant, which flows from the outdoor heat exchanger120to the indoor heat exchanger130. For example, the injection heat exchanger17may be installed inside a pipe17c, which is provided for the flow of the refrigerant, which has been condensed in the outdoor heat exchanger120during a cooling operation and has passed through the outdoor expansion valve150. Thereby, the refrigerant discharged from the indoor heat exchanger130passes through the interior of the injection heat exchanger17.

The injection heat exchanger17may be connected to the compressor110, the switching valve180, the indoor heat exchanger130, and the outdoor heat exchanger120. Specifically, for example, an inlet port17aof the injection heat exchanger17is connected to both the switching valve180and the compressor110, and an outlet port17bof the injection heat exchanger17is connected to the injection port112of the compressor110.

Accordingly, during a cooling operation, heat exchange between the refrigerant condensed in the outdoor heat exchanger120and the refrigerant evaporated in the indoor heat exchanger130occurs inside the injection heat exchanger17. The temperature of the evaporated refrigerant is thus raised and the temperature of the condensed refrigerant is lowered.

More specifically, the injection module may include a cooling bypass pipe172and a check valve174.

The cooling bypass pipe172may interconnect the indoor heat exchanger130and the injection heat exchanger17. Specifically, for example, one end of the cooling bypass pipe172is connected to the inlet pipe114, which interconnects the switching valve180and the compressor110, and the other end of the cooling bypass pipe172is connected to the injection heat exchanger17. During a cooling operation, the cooling bypass pipe172diverts the refrigerant discharged from the indoor heat exchanger130to the injection heat exchanger17. More specifically, for example, the other end of the cooling bypass pipe172is connected to a heating bypass pipe177, and the other end of the cooling bypass pipe172is connected to the heating bypass pipe177between the injection heat exchanger17and a second injection expansion valve171.

The cooling bypass pipe172may diverge from the inlet pipe114, which is connected to the indoor heat exchanger130and the inlet port111of the compressor110. The cooling bypass pipe172may thus divert at least a portion of the refrigerant introduced from the switching valve180to the gas-liquid separator140.

The check valve174may be installed in the cooling bypass pipe172to prevent the refrigerant from flowing from the injection heat exchanger17to the indoor heat exchanger130during a heating operation and also to allow the refrigerant having passed through the switching valve180to be introduced into the injection heat exchanger17during a cooling operation.

The injection module may further include an injection pipe175to interconnect the injection heat exchanger17and the compressor110, and a first injection expansion valve176installed in the injection pipe175. A portion of the refrigerant discharged from the indoor heat exchanger130may thus undergo heat exchange in the injection heat exchanger17, and then be introduced into the injection pipe175.

One end of the injection pipe175may be connected to the injection heat exchanger17, and the other end of the injection pipe175may be connected to the injection port112of the compressor110. The injection pipe175may be directly or indirectly connected to the heat exchanger17and the injection port112. The refrigerant having passed through the cooling bypass pipe172flows through the injection pipe175.

The first injection expansion valve176expands the refrigerant, which flows between the injection heat exchanger17and the compressor110. The opening degree of the first injection expansion valve176may be adjusted during a cooling operation so as to adjust the flow rate of the refrigerant to be injected into the compressor110. The first injection expansion valve176may be open during a heating operation and a cooling operation. Specifically, for example, the first injection expansion valve176may be fully open during a heating operation.

The injection module may further include a second injection expansion valve171for expanding a portion of the refrigerant, which flows from the indoor heat exchanger130to the outdoor heat exchanger120during a heating operation, and a heating bypass pipe177for diverting a portion of the refrigerant that flows from the indoor heat exchanger130to the outdoor heat exchanger120, whereby the second injection expansion valve171is provided in the heating bypass pipe177.

At this time, the injection heat exchanger17performs heat exchange between the refrigerant expanded in the second injection expansion valve171and a remaining portion of the refrigerant, which flows from the indoor heat exchanger130to the outdoor heat exchanger120during a heating operation. During a cooling operation, the injection heat exchanger17may perform heat exchange between the refrigerant discharged from the indoor heat exchanger130and the refrigerant, which flows from the outdoor heat exchanger120to the indoor heat exchanger130. During a heating operation, the injection heat exchanger17may perform heat exchange between a portion of the refrigerant, which moves from the indoor heat exchanger130to the outdoor heat exchanger120, and a remaining portion of the refrigerant.

The injection heat exchanger17may be connected to the first injection expansion valve176, the second injection expansion valve171, the overcooling heat-exchange hub190, the compressor110, and the indoor expansion valve160. During a heating operation, the injection heat exchanger17may perform heat exchange between the refrigerant expanded in the second injection expansion valve171and the refrigerant, which flows from the indoor heat exchanger130to the outdoor heat exchanger120. The injection heat exchanger17may guide the heat-exchanged refrigerant into the compressor110. That is, for example, during a heating operation, the refrigerant, which has undergone heat exchange in the injection heat exchanger17, is evaporated and introduced into the injection port112of the compressor110.

The heating bypass pipe177interconnects the indoor heat exchanger130and the injection heat exchanger17. Specifically, for example, one end of the heating bypass pipe177is connected to a pipe, which interconnects the indoor heat exchanger130and the outdoor heat exchanger120. The other end of the heating bypass pipe177is connected to the injection heat exchanger17. The heating bypass pipe177diverts a portion of the refrigerant, which flows from the indoor heat exchanger130to the outdoor heat exchanger120, to the injection heat exchanger17during a heating operation.

The heating bypass pipe177may be connected to the injection heat exchanger17separately from the cooling bypass pipe172, or may be combined with the cooling bypass pipe172and be connected to the injection heat exchanger17. The refrigerant having passed through the heating bypass pipe177and the injection heat exchanger17may thus be injected into the compressor110through the injection pipe175.

During a heating operation, the second injection expansion valve171expands at least a portion of the refrigerant, which flows from the indoor heat exchanger130to the outdoor heat exchanger120. The second injection expansion valve171may be open during a heating operation and closed during a cooling operation.

The second injection expansion valve171may be connected to the indoor expansion valve160and the injection heat exchanger17. The second injection expansion valve171functions to expand a portion of the refrigerant, which has been discharged from the indoor heat exchanger130and has passed through the indoor expansion valve160, and guide the refrigerant to the injection heat exchanger17during a heating operation.

The operation of the air conditioner having the above-described configuration in accordance with an embodiment of the present invention is described below.

FIG. 3is a view illustrating the flow of a refrigerant during a cooling operation of the air conditioner in accordance with one embodiment of the present invention.FIG. 4is a pressure-enthalpy diagram (P-H diagram) during the cooling operation of the air conditioner illustrated inFIG. 3.

Hereinafter, the operation of the air conditioner100in accordance with one embodiment of the present invention during a cooling operation will be described with reference toFIGS. 3 and 4.

As shown inFIG. 3, refrigerant compressed in the compressor110may be discharged from the outlet port113and flow to the switching valve180. The refrigerant, discharged from the outlet port113passes through a point “b”. At this time, the refrigerant at the point “b” is in a high-temperature and high-pressure state, such as illustrated inFIG. 4.

Because the switching valve180interconnects the outlet port113of the compressor110and the outdoor heat exchanger120during a cooling operation, the refrigerant that flows to the switching valve180passes through a point “h” and flows to the outdoor heat exchanger120. The refrigerant passing through point “h” remains at the same pressure, but is slightly lowered in temperature as compared with the refrigerant at the point “b”.

The refrigerant that flows from the switching valve180to the outdoor heat exchanger120is condensed via heat exchange with outdoor air in the outdoor heat exchanger120. The refrigerant condensed in the outdoor heat exchanger120passes through a point “g” and moves to the outdoor expansion valve150. The condensed refrigerant at the point “g” remains at the same pressure, but is greatly lowered in temperature compared to the refrigerant at the point “h”.

The refrigerant condensed in the outdoor heat exchanger120flows to the outdoor expansion valve150. During a cooling operation, the outdoor expansion valve150may be fully open so that the refrigerant passes, thereby guiding the refrigerant to the overcooling heat-exchange hub190.

During a cooling operation, the brine stored in the overcooling heat-exchange hub190may be forcibly moved to the gas-liquid separator jacket200via the driving of the circulation pump191. The brine moved from the overcooling heat-exchange hub190to the gas-liquid separator jacket200is lowered in temperature via heat exchange with the gas-liquid separator140. The low-temperature brine, which has undergone heat exchange with the gas-liquid separator140, may then be stored in the overcooling heat-exchange hub190via the driving of the circulation pump191.

The refrigerant that flows from the outdoor expansion valve150to the overcooling heat-exchange hub190may flow through a pipe installed inside the overcooling heat-exchange hub190. The refrigerant undergoes heat exchange with the brine while flowing through the pipe. The refrigerant, which has undergone heat exchange in the overcooling heat-exchange hub190, may then pass through a point “j” and flow to the injection heat exchanger17. The refrigerant at the point “j” remains at the same pressure, but is lowered in temperature compared to the refrigerant at the point “h”.

Thus, because the second injection expansion valve171of the injection module is closed and the first injection expansion valve176is open during a cooling operation, the refrigerant having passed through the point “j” undergoes heat exchange with at least a portion of the refrigerant discharged from the injection heat exchanger17. The refrigerant having passed through the injection heat exchanger17passes through a point “e” and flows to the indoor expansion valve160. The refrigerant at the point “e” remains at the same pressure, but is lowered in temperature compared to the refrigerant at the point “j”.

The refrigerant that flows to the indoor expansion valve160passes through a point “d” and moves to the indoor heat exchanger130. The refrigerant having passed through the point “d” remains at the same temperature, but has a significantly lower pressure compared to the refrigerant at the point “e”. However, in some embodiments, the refrigerant passing through the point “d” may be slightly lowered in temperature and may be significantly lowered in pressure compared to the refrigerant at the point “e”.

The refrigerant moved to the indoor heat exchanger130is evaporated via heat exchange with indoor air in the indoor heat exchanger130. The refrigerant evaporated in the indoor heat exchanger130passes through a point “c” and flows to the switching valve180. The refrigerant having passed through the point “C” remains at the same pressure but has a higher temperature compared to the refrigerant at the point “d”. The temperature of the refrigerant at point “c” may be significantly higher compared to the refrigerant at point “d”.

Thus, for example, because the switching valve180interconnects the indoor heat exchanger130and the gas-liquid separator140and/or the compressor110during a cooling operation, the refrigerant that flows from the indoor heat exchanger130to the switching valve180is introduced into the gas-liquid separator140. The refrigerant introduced into the gas-liquid separator140is separated into gas-phase refrigerant and liquid-phase refrigerant. The gas-phase refrigerant passes through a point “a” and moves to the inlet port111of the compressor110. The refrigerant having passed through the point “a” remains at the same pressure, but has a higher temperature compared to the refrigerant at the point “c”. This is because only the gas-phase refrigerant having a relatively high temperature among the refrigerant introduced into the gas-phase separator140flows to the inlet port111of the compressor110. The temperature of the refrigerant at point “a” may be significantly higher compared to the refrigerant at point “c”.

The refrigerant moved to the inlet port111is then compressed in the compressor110, and thereafter discharged via the outlet port113. That is, for example, the refrigerant introduced into the compressor110is compressed, thus becoming high-temperature and high-pressure refrigerant at the point “b” shown inFIG. 4.

A portion of the refrigerant, which has passed through the switching valve180, but has not yet been introduced into the gas-liquid separator140, may be diverted to the cooling bypass pipe172so as to pass through a point “f” and be introduced into the injection heat exchanger17. The refrigerant having passed through the point “f” undergoes heat exchange in the injection heat exchanger17, and thereafter, passes through a point “i” and is introduced into the injection pipe175. The refrigerant at the point “i” has a higher temperature compared to the refrigerant at the point “f”. Alternatively, the refrigerant at the point “i” has higher temperature and pressure compared to the refrigerant at the point “f”.

The refrigerant having passed through the point “i” flows to the injection port112of the compressor110.

Accordingly, for example, when the injection module is used during a cooling operation, the overcooling degree and the cooling ability are increased and the enthalpy of the refrigerant suctioned into the compressor110is increased, which reduces power consumption of the compressor110.

FIG. 5is a view illustrating the flow of a refrigerant during a heating operation of the air conditioner in accordance with one embodiment of the present invention.FIG. 6is a pressure-enthalpy diagram (P-H diagram) during the heating operation of the air conditioner illustrated inFIG. 5.

Hereinafter, the operation of the air conditioner100in accordance with one embodiment of the present invention during a heating operation will be described with reference toFIGS. 5 and 6.

As shown inFIG. 5, refrigerant compressed in the compressor110is discharged from the outlet port113and flows to the switching valve180. The refrigerant discharged from the outlet port113then passes through a point “b”. At this time, the refrigerant at the point “b” is in a high-temperature and high-pressure state, such as illustrated inFIG. 6.

Thus, for example, because the switching valve180interconnects the outlet port113of the compressor110and the indoor heat exchanger130during a heating operation, the refrigerant moved to the switching valve180passes through a point “c” and flows to the indoor heat exchanger130. The refrigerant passing through the point “c” remains at the same pressure, but has a lower temperature compared to the refrigerant at the point “b”. The temperature of the refrigerant at point “c” may be slightly lower compared to the refrigerant at point “b”.

The refrigerant may then be condensed via heat exchange with indoor air in the indoor heat exchanger130. For example, the refrigerant condensed in the indoor heat exchanger130passes through a point “d” and flows to the indoor expansion valve160. The refrigerant at the point “d” remains at the same pressure, but has a lower temperature compared to the refrigerant at the point “c” due to condensation in the indoor heat exchanger130. The temperature of the refrigerant at point “d” may be significantly lower compared to the refrigerant at point “c”.

The refrigerant condensed in the indoor heat exchanger130may flow to the indoor expansion valve160. During a heating operation, the indoor expansion valve160may be fully open so that the refrigerant passes, thereby guiding the refrigerant to the injection heat exchanger17.

Thus, for example, because the second injection expansion valve171of the injection module is open and the first injection expansion valve176is completely open during a heating operation, a portion of the refrigerant having passed through the indoor expansion valve160flows through a point “e” and moves to the second injection expansion valve171. The refrigerant having passed through the point “e” remains at the same pressure, but has a lower temperature compared to the refrigerant having passed through the point “d”. The temperature of the refrigerant at point “e” may be slightly lower compared to the refrigerant at point “d”.

During a heating operation, the opening degree of the second injection expansion valve171may be adjusted so as to expand the refrigerant. Accordingly, for example, the refrigerant, moved to and expanded by the second injection expansion valve171, flows through a point “f” and moves to the injection heat exchanger17. The refrigerant passing through the point “f” remains at the same temperature, but has a lower pressure compared to the refrigerant at the point “e”. The check valve174prevents the refrigerant passing through the point “f” from moving to the switching valve180.

The refrigerant expanded in the second injection expansion valve171may then be guided to the injection heat exchanger17and pass through the indoor expansion valve160, thereby being evaporated via heat exchange with the refrigerant, which moves to the outdoor heat exchanger120. For example, the evaporated refrigerant flows through a point “i” and moves to the injection port112of the compressor110. The refrigerant passing through the point “i” remains at the same pressure, but has a higher temperature compared to the refrigerant at the point “f”. Alternatively, the refrigerant passing through the point “i” has a higher temperature and pressure than the refrigerant passing through a point “a”, which will be described below.

Among the refrigerant moving from the indoor expansion valve160to the outdoor heat exchanger120, for example, the portion of refrigerant that is not introduced into the second injection expansion valve171is overcooled via heat exchange with the refrigerant expanded in the second injection expansion valve171. The overcooled refrigerant passes through a point “j” and moves to the overcooling heat-exchange hub190. The refrigerant having passed through the point “j” remains at the same pressure, but has a lower temperature compared to the refrigerant at the point “e”.

The circulation pump191is not driven during a heating operation, and thus the brine is not forcibly circulated. Accordingly, the brine may not undergo heat exchange with the gas-liquid separator140. Therefore, the refrigerant having passed through the overcooling heat-exchange hub190may exhibit almost no variation in pressure and temperature compared to the refrigerant at the point “j”. The refrigerant having passed through the overcooling heat-exchange hub190moves to the outdoor expansion valve150.

However, in some embodiments, the brine may be circulated to the gas-liquid separator jacket200due to natural circulation even when the circulation pump191is not driven. The brine may absorb cold energy of the gas-liquid separator140via natural circulation, and may be stored in the overcooling heat-exchange hub190. Accordingly, the refrigerant having passed through the overcooling heat-exchange hub190may remain at the same pressure, but may have a lower temperature compared to the refrigerant at the point “j”. The temperature of the refrigerant passed through the overcooling heat-exchange hub190may be slightly lower compared to the refrigerant at point “j”.

The refrigerant moved to the outdoor expansion valve150is then expanded, and passes through a point “g” and moves to the outdoor heat exchanger120. The refrigerant passing through the point “g” remains at the same temperature, but has a lower pressure compared to the refrigerant having passed through the overcooling heat-exchange hub190or the refrigerant at the point “j”. The pressure of the refrigerant passed through point “g” may be significantly lower compared to the refrigerant at the point “j”.

However, in some embodiments, the refrigerant passing through the point “g” may have a lower temperature and a lower pressure compared to the refrigerant having passed through the overcooling heat-exchange hub190or the refrigerant at the point “j”. For example, the refrigerant passing through point “g” may have a slightly lower temperature and a significantly lower pressure compared to the refrigerant passed through the overcooling heat-exchange hub190or the refrigerant at point “j”.

The refrigerant expanded in the outdoor expansion valve150may then moves to the outdoor heat exchanger120, and in turn, the refrigerant moved to the outdoor heat exchanger120may be evaporated via heat exchange with outdoor air. For example, the refrigerant evaporated in the outdoor heat exchanger120passes through a point “h” and moves to the switching valve180. The refrigerant passing through the point “h” remains at the same pressure, but has a higher temperature compared to the refrigerant at the point “g”. The temperature of the refrigerant passed through point “h” may be significantly higher compared to the refrigerant at point “g”.

Thus, for example, because the switching valve180interconnects the outdoor heat exchanger120and the gas-liquid separator140during a heating operation, the refrigerant moved from the outdoor heat exchanger120to the switching valve180may be introduced into the gas-liquid separator140. The refrigerant introduced into the gas-liquid separator140is separated into gas-phase refrigerant and liquid-phase refrigerant. The gas-phase refrigerant passes through a point “a” and moves to the inlet port111of the compressor110. The refrigerant having passed through the point “a” remains at the same pressure, but has a higher temperature compared to the refrigerant at the point “c”. This is because only the gas-phase refrigerant having a relatively high temperature among the refrigerant introduced into the gas-phase separator140moves to the inlet port111of the compressor110. The temperature of the refrigerant passed through point “a” may be slightly higher compared to the refrigerant at point “c”.

The refrigerant moved to the inlet port111may be compressed in the compressor110. During compression, the refrigerant is combined in the injection port112with the refrigerant evaporated in the injection module. Thereby, the temperature and pressure of the refrigerant being compressed are lowered to those at the point “i”. After such combination, the combined refrigerant is again compressed, thus becoming high-temperature and high-pressure refrigerant at the point “b”. The high-temperature and high-pressure refrigerant is discharged through the outlet port113. As the refrigerant having passed through the point “i” is injected into the compressor110, the temperature of the refrigerant discharged through the outlet port113is lowered compared to the temperature when the refrigerant is not injected. This may prevent an overload of the compressor110.

FIG. 7is a block diagram illustrating the air conditioner in accordance with one embodiment of the present invention. The operating steps of the air conditioner100during a cooling operation in accordance with one embodiment of the present invention will be described below with reference toFIG. 7.

A controller10controls the air conditioner to perform a cooling operation. When the controller10switches the switching valve180upon beginning the cooling operation, the switching valve180interconnects the outlet port113of the compressor110and the outdoor heat exchanger120, thus guiding the refrigerant discharged from the compressor110to the outdoor heat exchanger120.

When beginning the cooling operation, the controller10drives the circulation pump191to forcibly circulate brine that may be stored in the overcooling heat-exchange hub190to the gas-liquid separator jacket200. The brine forcibly circulated to the gas-liquid separator jacket200may then be cooled via heat exchange with the gas-liquid separator140. The cooled brine may then move to the overcooling heat-exchange hub190and be stored therein.

The refrigerant, which has passed through the outlet port113of the compressor110and the switching valve180and has moved to the outdoor heat exchanger120, may then undergo a heat exchange process with outdoor air in the outdoor heat exchanger120. Thereby, the refrigerant passing through the outdoor heat exchanger120is condensed.

When beginning the cooling operation, the controller10controls the outdoor expansion valve150so that it is fully opened in order to guide the refrigerant condensed in the outdoor heat exchanger120to the overcooling heat-exchange hub190. Then, the controller10may control heat exchange between the refrigerant and the brine in the overcooling heat-exchange hub190so as to overcool the refrigerant. The overcooled refrigerant may then move to the injection heat exchanger17.

The controller10may close the second injection expansion valve171and open the first injection expansion valve176, thereby injecting at least a portion of the refrigerant, which has completely undergone heat exchange with indoor air and has been discharged from the indoor heat exchanger130, into the compressor110.

The controller10may then cause the refrigerant introduced into the indoor expansion valve160to expand by adjusting the opening degree of the indoor expansion valve160. The refrigerant expanded in the indoor expansion valve160may move to the indoor heat exchanger130. The refrigerant moved to the indoor heat exchanger130may be evaporated via heat exchange with indoor air. The refrigerant evaporated in the indoor heat exchanger130may move to the switching valve180.

Thus, when beginning the cooling operation, the controller10interconnects the indoor heat exchanger130and the gas-liquid separator140. The refrigerant evaporated in the indoor heat exchanger130may move to the gas-liquid separator140. The refrigerant moved to the gas-liquid separator140is then separated into gas-phase refrigerant and liquid-phase refrigerant, and only the gas-phase refrigerant moves to the inlet port111of the compressor110.

The controller10may then cause the refrigerant to be compressed by adjusting the operational speed of the compressor110based on the control logic of the cooling operation. The high-temperature and high-pressure refrigerant may be discharged from the compressor110to the switching valve180through the outlet port113.

As is appreciated from the above disclosure, an air conditioner of the embodiments of the present invention has at least one or more of the following effects.

During a cooling operation, a portion of the refrigerant, which has already undergone heat exchange with outdoor air in an indoor heat exchanger, is injected into a compressor, which advantageously results in increased efficiency.

Additionally, during a cooling operation, the refrigerant is overcooled by collecting cold energy from a portion of the refrigerant, which has already undergone heat exchange with outdoor air in the indoor heat exchanger, thereby advantageously preventing deterioration in the mass flow rate of refrigerant moving to the indoor heat exchanger.

Additionally, the refrigerant is injected into the compressor along different paths during a cooling operation and a heating operation, which advantageously results in increased efficiency of a heating operation and a cooling operation.

It should be noted that effects of the present invention are not limited to the effects of the present invention as mentioned above, and other unmentioned effects of the present invention will be clearly understood by those skilled in the art from the following description.

The above described features, configurations, effects, and the like are included in at least one of the embodiments of the present invention, and should not be limited to only one embodiment. In addition, the features, configurations, effects, and the like as illustrated in each embodiment may be implemented with regard to other embodiments as they are combined with one another or modified by those skilled in the art. Thus, content related to these combinations and modifications should be construed as including in the scope and spirit of the invention as disclosed in the accompanying claims.