Patent Description:
An air conditioner is a device for cooling/heating indoor air or purifying the indoor air to provide a user with a more comfortable indoor environment. These days, for more efficient cooling or heating of an indoor space which is divided into multiple rooms, there has been continuous development of a multi-type air conditioner for cooling or heating each room.

In the multi-type air conditioner, multiple indoor units are connected to one outdoor unit, and at least one indoor unit is installed in each room, in which the indoor unit performs either a heating operation or a cooling operation for conditioning the indoor air. A distributor for connecting the outdoor unit and the indoor units may be provided in the multi-type air conditioner, in which a refrigerant pipe is connected to the distributor so that gaseous refrigerant or liquid refrigerant may be supplied to the indoor units according to requirements of the indoor space.

A general multi-type air conditioner is classified into a type in which all of a plurality of indoor units performs a cooling operation or a heating operation, and a type in which some of the plurality of indoor units performs the cooling operation, and the rest of the indoor units performs the heating operation. However, in the general multi-type air conditioner, even when some of the plurality of indoor units performs the cooling operation and the rest of the indoor units performs the heating operation, outside air and indoor air may not be circulated. In addition, the general multi-type air conditioner has a problem in that when some of the plurality of indoor units performs the cooling operation and the rest of the indoor units performs the heating operation, waste heat from any one indoor unit is not recovered, thereby resulting in low efficiency.

<CIT> discloses a separate-type air conditioner which comprises an indoor unit having one air inlet, two air outlets, a fan for each outlet, one heat exchanger for one outlet, and two heat exchangers for the other outlet.

Advantages and features of embodiments will be more clearly understood from exemplary embodiments described below with reference to the accompanying drawings. However, the embodiments are not limited to the following embodiments but may be implemented in various different forms. The embodiments are provided only to complete disclosure and to fully provide a person having ordinary skill in the art to which the embodiments pertain with the category, and the present invention is defined by the scope of the appended claims. Wherever possible, like reference numerals generally denote like elements through the specification.

Hereinafter, embodiments will be described with reference to the accompanying drawings.

<FIG> is a schematic perspective view of a multi-type air conditioner according to an embodiment of the present invention. Referring to <FIG>, the multi-type air conditioner according to an embodiment includes an outdoor unit A and indoor units B.

According to the invention, there are a plurality of indoor units B which may perform a cooling operation or a heating operation. In this embodiment, both the indoor units B may perform the cooling operation or the heating operation. Further, in this embodiment, while some of the indoor units B performs the cooling operation, the other indoor units B may perform the heating operation. The indoor units B may cool, heat, or dehumidify outside air drawn in from the outside.

<FIG> is a diagram illustrating an outdoor unit of the multi-type air conditioner of <FIG>. Referring to <FIG>, the outdoor unit A may include a first compressor <NUM>; a first oil separator <NUM> that separates oil from refrigerant discharged from the first compressor <NUM>; a second compressor <NUM>; a second oil separator <NUM> that separates oil from a refrigerator discharged from the second compressor <NUM>; a first four-way valve <NUM> connected to the first oil separator <NUM> and the second oil separator <NUM> to receive refrigerant, and connected to the indoor units B to circulate the refrigerant; an accumulator <NUM> connected to the first compressor <NUM> and the second compressor <NUM> to supply refrigerant; an outdoor heat exchanger <NUM> that performs heat exchange between refrigerant and air; a second four-way valve <NUM> that connects the accumulator <NUM>, the outdoor heat exchanger <NUM>, and the first four-way valve <NUM>; and a supercooler <NUM> disposed between the indoor unit B and the outdoor heat exchanger <NUM> and that supercools the refrigerant. In this embodiment, an inverter compressor is used as the first compressor <NUM> and the second compressor <NUM>.

The outdoor unit A may further include a first oil pipe 13a that connects the first oil separator <NUM> and the first compressor <NUM> and returns oil to the first compressor <NUM>; a valve 13b disposed in the first oil pipe 13a and controlling a flow of oil; and a check valve 13c disposed in the first oil pipe 13a and causing the oil to flow only toward the first compressor <NUM>. The outdoor unit A may further include a second oil pipe 14a that connects the second oil separator <NUM> and the second compressor <NUM> and returns oil to the second compressor <NUM>; a valve 14b disposed in the second oil pipe 14a and controlling a flow of oil; and a check valve 14c disposed in the second oil pipe 14a and causing the oil to flow only toward the second compressor <NUM>.

The first four-way valve <NUM> may receive refrigerant from the first oil separator <NUM> and the second oil separator <NUM>. The first four-way valve <NUM> may include a <NUM>-<NUM> passage <NUM>, a <NUM>-<NUM> passage <NUM>, a <NUM>-<NUM> passage <NUM>, and a <NUM>-<NUM> passage <NUM>.

The <NUM>-<NUM> passage <NUM> may be connected to the indoor units B, and a high-pressure pipe <NUM> may be connected to the <NUM>-<NUM> passage <NUM>. The <NUM>-<NUM> passage <NUM> may be connected to the indoor units B, and a low-pressure pipe <NUM> may be connected to the <NUM>-<NUM> passage <NUM>.

The <NUM>-<NUM> passage <NUM> may be connected to the first oil separator <NUM> and the second oil separator <NUM>, and a refrigerant supply pipe <NUM> may be connected to the <NUM>-<NUM> passage <NUM>. The refrigerant supply pipe <NUM> may be connected to the first oil separator <NUM> and the second oil separator <NUM>. The refrigerant supply pipe <NUM> may be branched to be connected to the first oil separator <NUM> and the second oil separator <NUM>.

In this embodiment, the refrigerant supply pipe connected to the first oil separator <NUM> will be referred to as a "first refrigerant supply pipe" 35a, and the refrigerant supply pipe connected to the second oil separator <NUM> will be referred to as a "second refrigerant supply pipe" 35b. Further, in this embodiment, the <NUM>-<NUM> passage <NUM> is closed.

The second four-way valve <NUM> may include a <NUM>-<NUM> passage <NUM>, a <NUM>-<NUM> passage <NUM>, a <NUM>-<NUM> passage <NUM>, and a <NUM>-<NUM> passage <NUM>. The <NUM>-<NUM> passage <NUM> may be connected to the first four-way valve <NUM>, and in this embodiment, may be connected to the refrigerant supply pipe <NUM>. A pipe that connects the <NUM>-<NUM> passage <NUM> and the refrigerant supply pipe <NUM> will be referred to as a "first four-way valve pipe" <NUM>. The <NUM>-<NUM> passage <NUM> may be connected to the outdoor heat exchanger <NUM>. A pipe that connects the <NUM>-<NUM> passage <NUM> and the outdoor heat exchanger <NUM> will be referred to as a "second four-way valve pipe" <NUM>.

The outdoor heat exchanger <NUM> may include a first outdoor heat exchanger <NUM> and a second outdoor heat exchanger <NUM>, and the second four-way valve pipe <NUM> may be connected in parallel to the first outdoor heat exchanger <NUM> and the second outdoor heat exchanger <NUM>. A pipe branched from the second four-way valve pipe <NUM> to be connected to the first outdoor heat exchanger <NUM> will be referred to as a "<NUM>-<NUM> four-way valve pipe" 112a, and a pipe connected to the second outdoor heat exchanger <NUM> will be referred to as a "<NUM>-<NUM> four-way valve pipe" 112b.

The <NUM>-<NUM> passage <NUM> may be connected to the accumulator <NUM>. A pipe that connects the <NUM>-<NUM> passage <NUM> and the accumulator <NUM> will be referred to as a "third four-way valve pipe" <NUM>. In this embodiment, the <NUM>-<NUM> passage <NUM> is closed.

In the outdoor unit A, a pipe that connects the third four-way valve pipe <NUM> and the <NUM>-<NUM> passage <NUM> will be referred to as a "fourth four-way valve pipe" <NUM>. A pipe that connects the supercooler <NUM> and the outdoor heat exchanger <NUM> will be referred to as a "supercooler-outdoor heat exchanger connection pipe" <NUM>.

The outdoor heat exchanger <NUM> may include the first outdoor heat exchanger <NUM> and the second outdoor heat exchanger <NUM>, such that the connection pipe <NUM> is branched. The connection pipe <NUM> may include a first connection pipe 116a connected to the supercooler <NUM>; a second connection pipe 116b branched from the first connection pipe 116a to be connected to the first outdoor heat exchanger <NUM>; and a third connection pipe 116c branched from the first connection pipe 116a to be connected to the second outdoor heat exchanger <NUM>.

A first outdoor expansion valve <NUM> may be disposed in the second connection pipe 116b, and a second outdoor expansion valve <NUM> may be disposed in the third connection pipe 116c. An expansion valve bypass pipe <NUM> may be provided , which is connected to the third connection pipe 116c by bypassing the second outdoor expansion valve <NUM>, and one or a first end of the expansion valve bypass pipe <NUM> is connected to the third connection pipe 116c disposed between the second outdoor heat exchanger <NUM> and the second outdoor expansion valve <NUM>, and the other or a second end thereof is connected to the third connection pipe 116c disposed between the supercooler <NUM> and the second outdoor expansion valve <NUM>.

A check valve <NUM> may be disposed in the expansion valve bypass pipe <NUM>. The check valve <NUM> may cause refrigerant to flow from the second outdoor heat exchanger <NUM> only toward the supercooler <NUM>.

A pipe that connects the supercooler <NUM> and the indoor units B will be referred to as a "liquid line" <NUM>. The liquid line <NUM> may be connected to the connection pipe <NUM> through the supercooler <NUM>.

The supercooler <NUM> may include a supercooling heat exchanger <NUM>; a supercooling bypass pipe <NUM> branched from the liquid line <NUM> to be connected to the supercooling heat exchanger <NUM>; a supercooling expansion valve <NUM> disposed in the supercooling bypass pipe <NUM>; a supercooler-accumulator connection pipe <NUM> that connects the supercooling heat exchanger <NUM> and the accumulator <NUM>; and the valve <NUM> disposed in the connection pipe <NUM>. An electronic expansion valve may be used as the supercooling expansion valve <NUM>. By controlling an opening degree of the supercooling expansion valve <NUM>, a portion of the refrigerant flowing to the liquid line <NUM> may be bypassed to the supercooling heat exchanger <NUM>. The refrigerant expanded in the supercooling expansion valve <NUM> may be expanded in the supercooling heat exchanger <NUM> and may cool the refrigerant flowing from the first connection pipe 116a to the liquid line <NUM>. When the valve <NUM> is open, the refrigerant evaporated in the supercooling heat exchanger <NUM> may be supplied to the accumulator <NUM> through the connection pipe <NUM>.

A pipe for bypassing the refrigerant of the supercooling heat exchanger <NUM> to the compressor may be provided. In this embodiment, supercooler-compressor connection pipes <NUM> and <NUM>, which are branched from the supercooling bypass pipe <NUM> to be bypassed to the first compressor <NUM>, and expansion valves <NUM> and <NUM> disposed in the connection pipes <NUM> and <NUM> may be further included. Of the supercooler-compressor connection pipes <NUM> and <NUM>, one that is connected to the first compressor <NUM> will be referred to as a "first supercooler-compressor connection pipe" <NUM>, and the other that is connected to the second compressor <NUM> will be referred to as a "second supercooler-compressor connection pipe" <NUM>.

The expansion valves <NUM> and <NUM> may be disposed in the first supercooler-compressor connection pipe <NUM> and the second supercooler-compressor connection pipe <NUM>, respectively. The expansion valves <NUM> and <NUM> may be electronic expansion valves which may control an opening degree.

A pipe that connects the accumulator <NUM> and the compressor will be referred to as an "accumulator-compressor connection pipe" <NUM>. In this embodiment, the accumulator-compressor connection pipe may be branched into two pipes to be connected to the first compressor <NUM> and the second compressor <NUM>. Of the accumulator-compressor connection pipes, one that is connected to the first compressor <NUM> will be referred to as a "first accumulator-compressor connection pipe" 15a, and the other that is connected to the second compressor <NUM> will be referred to as a "second accumulator-compressor connection pipe" 15b.

An oil equalizing pipe <NUM> may be further included for maintaining an equal level of liquid refrigerant and oil stored in the first compressor <NUM> and the second compressor <NUM>. In the oil equalizing pipe <NUM>, valves 17a and 17b may be disposed at a side of the first compressor <NUM> and at a side of the second compressor <NUM>, respectively, and the amount of oil to be discharged may be controlled by opening and closing the valves 17a and 17b. In addition, a bypass pipe <NUM> may be further provided that connects the oil equalizing pipe <NUM> and the accumulator-compressor connection pipe <NUM>.

<FIG> is a diagram of indoor units of the multi-type air conditioner of <FIG>. Referring to <FIG>, the indoor unit B includes a case <NUM>, and a first indoor heat exchanger <NUM> and a second indoor heat exchanger <NUM> which are disposed in the case <NUM>. The case <NUM> includes a first inlet <NUM> through which outside air may be drawn in; a first outlet <NUM> through which air, having passed through the first indoor heat exchanger <NUM> and the second heat exchanger <NUM>, may be discharged into a room; a second inlet <NUM> through which indoor air may be drawn in; and a second outlet <NUM> through which air inside the case <NUM> may be discharged to the outside.

The indoor unit B further includes, inside the case <NUM>, a first indoor unit passage <NUM> that connects the first inlet <NUM> and the first outlet <NUM>; a second indoor unit passage <NUM> that connects the second inlet <NUM> and the second outlet <NUM>; and an indoor unit bypass passage <NUM> that connects the first indoor unit passage <NUM> and the second indoor unit passage <NUM>.

The first indoor heat exchanger <NUM> and the second indoor heat exchanger <NUM> are disposed on the first indoor unit passage <NUM>. Air flowing through the first indoor unit passage <NUM> may be heat-exchanged with the second indoor heat exchanger <NUM> and the first indoor heat exchanger <NUM>. That is, the air in the first indoor unit passage <NUM> flows in the order of the first inlet <NUM>, the second indoor heat exchanger <NUM>, the first indoor heat exchanger <NUM>, and the first outlet <NUM>.

Air in the second indoor unit passage <NUM> may flow from the second inlet <NUM> to the second outlet <NUM>. As damper <NUM> opens and closes, the air in the second indoor unit passage <NUM> may be bypassed to the first indoor unit passage <NUM>, and then may flow in the order of the second indoor heat exchanger <NUM>, the first indoor heat exchanger <NUM>, and the first outlet <NUM>. A first indoor fan <NUM> may be disposed in the first indoor unit passage <NUM>, and a second indoor fan <NUM> may be disposed in the second indoor unit passage <NUM>.

The indoor unit B may include the damper <NUM> disposed in the indoor bypass passage <NUM> and controlling an air flow amount in the indoor bypass passage <NUM>. By controlling an opening degree of the damper <NUM>, a portion of the air discharged from the inside to the outside may return toward the first indoor unit passage <NUM>. By controlling the damper <NUM> to return the discharged indoor air, an indoor load may be reduced.

The indoor unit B may further include a high pressure valve <NUM> connected to the high pressure pipe <NUM> and controlling a flow of refrigerant; a low pressure valve <NUM> connected to the low pressure pipe <NUM> and controlling a flow of refrigerant; an indoor high pressure pipe <NUM> that connects the high pressure valve <NUM> and the high pressure pipe <NUM>; an indoor high-pressure bypass pipe <NUM> that connects the indoor high pressure pipe <NUM> and the first indoor heat exchanger <NUM>; an indoor low pressure pipe <NUM> that connects the low pressure valve <NUM> and the low pressure pipe <NUM>; an indoor supercooler <NUM> disposed between the indoor low pressure pipe <NUM> and the indoor heat exchangers <NUM> and <NUM> and that selectively supercools flowing refrigerant; an indoor supercooler-liquid line connection pipe <NUM> that connects the indoor supercooler <NUM> and the liquid line <NUM>; a first supercooler connection pipe <NUM> that connects the first indoor heat exchanger <NUM> and the indoor supercooler <NUM>; and a second supercooler connection pipe <NUM> that connects the second indoor heat exchanger <NUM> and the indoor supercooler <NUM>.

A first indoor expansion valve <NUM> may be disposed in the first supercooler connection pipe <NUM>, and a second indoor expansion valve <NUM> may be disposed in the second supercooler connection pipe <NUM>. An electronic expansion valve may be used as the first indoor expansion valve <NUM> and the second indoor expansion valve <NUM>.

Both the high-pressure valve <NUM> and the low-pressure valve <NUM> may be connected to the second indoor heat exchanger <NUM>. A pipe that connects the high pressure value <NUM> and the second indoor heat exchanger <NUM> will be referred to as a "high pressure valve-second indoor heat exchanger connection pipe" <NUM>, and a pipe that connects the low pressure value <NUM> and the second indoor heat exchanger <NUM> will be referred to as a "low pressure valve-second indoor heat exchanger connection pipe" <NUM>.

The connection pipes <NUM> and <NUM> may be connected in series to the second indoor heat exchanger <NUM>. In this embodiment, a junction pipe <NUM> may be further included, to which the connection pipes <NUM> and <NUM> may be joined, and the junction pipe <NUM> may be connected to the second indoor heat exchanger <NUM>.

The indoor unit B may further include a low-pressure bypass pipe <NUM> that connects the junction pipe <NUM> and the indoor low-pressure pipe <NUM>. A third expansion valve <NUM> is disposed in the low-pressure bypass pipe <NUM>. In this embodiment, an electronic expansion valve may be used as the third expansion valve <NUM>.

The first supercooler connection pipe <NUM> and the second supercooler connection pipe <NUM> may be connected to the indoor supercooler <NUM>, and in this embodiment, the first supercooler connection pipe <NUM> and the second supercooler connection pipe <NUM> may be joined to be connected to the indoor supercooler <NUM>. The indoor supercooler <NUM> may selectively supercool liquid refrigerant supplied from the first supercooler connection pipe <NUM> and the second supercooler connection pipe <NUM> by bypassing and evaporating a portion of the liquid refrigerant flowing in the indoor supercooler <NUM>.

The indoor supercooler <NUM> includes an indoor supercooling heat exchanger <NUM> disposed in the second supercooler connection pipe <NUM>; an indoor supercooling bypass pipe <NUM> branched from the second supercooler connection pipe <NUM> to be connected to the indoor supercooling heat exchanger <NUM>; an indoor supercooling expansion valve <NUM> disposed in the indoor supercooling bypass pipe <NUM>; and an indoor supercooler return line <NUM> that connects the indoor supercooling heat exchanger <NUM> and the indoor low pressure pipe <NUM>. The second supercooler connection pipe <NUM> connects the indoor supercooling heat exchanger <NUM> and the second supercooling heat exchanger <NUM>.

One or a first end of the indoor supercooling bypass pipe <NUM> may be connected to the indoor supercooler-liquid line connection pipe <NUM>, and the other or a second end thereof may be connected to the indoor supercooling heat exchanger <NUM>. By controlling an opening degree of the first indoor expansion valve <NUM>, the controller may selectively expand the refrigerant flowing through the first supercooler connection pipe <NUM>, and by controlling an opening degree of the second indoor expansion valve <NUM>, the controller may selectively expand the refrigerant flowing through the second supercooler connection pipe <NUM>.

<FIG> is a table showing an operating state of indoor heat exchangers according to an operation mode of the multi-type air conditioner of <FIG>. Referring to <FIG>, a cooling mode is classified into two modes for one indoor unit B in this embodiment.

First, in a case in which refrigerant is condensed in the first indoor heat exchanger <NUM>, and the refrigerant is evaporated in the second indoor heat exchanger <NUM>, air passing through the first indoor passage <NUM> is reheated/dehumidified, and air cooled in the second indoor heat exchanger <NUM> is heated in the first indoor heat exchanger <NUM>. By controlling the indoor unit in this manner, air at a similar temperature to the indoor air may be discharged from the first outlet <NUM>, and by controlling an amount of refrigerant supplied to the first indoor heat exchanger <NUM> or the second indoor heat exchanger <NUM>, the indoor unit may be operated in response to a low cooling load.

Second, in a case in which a flow of refrigerant to the first indoor heat exchanger <NUM> is blocked, and the refrigerant is evaporated in the second indoor heat exchanger <NUM>, only the second indoor heat exchanger <NUM> operates such that the air passing through the first indoor unit passage <NUM> is cooled, and cold air is discharged through the first outlet <NUM> of the indoor unit B. In this case, the indoor unit may be operated in response to a high cooling load of a room.

In this embodiment, a heating mode is also classified into two modes for one indoor unit B.

First, in a case in which refrigerant is condensed in the first indoor heat exchanger <NUM> and the second indoor heat exchanger <NUM>, condensation heat is released from the first indoor heat exchanger <NUM> and the second indoor heat exchanger <NUM>, and heated air is discharged through the first outlet <NUM> of the indoor unit B. As heat is released from both the first indoor heat exchanger <NUM> and the second indoor heat exchanger <NUM>, the indoor unit may be operated in response to a high heating load.

Second, in a case in which a flow of refrigerant to the first indoor heat exchanger <NUM> is blocked, and the refrigerant is condensed in the second indoor heat exchanger <NUM>, heat is released from only the second indoor heat exchanger <NUM>, such that the indoor unit may be operated in response to a low heating load.

A heating-only operation mode is an operation mode in which all the plurality of indoor units B are operated in a heating mode, and a cooling-only operation mode is an operation mode in which all of the plurality of indoor units B are operated in a cooling mode. A heating-main simultaneous operation mode is a mode in which some of the plurality of indoor units B are operated in a heating mode, and the rest of the indoor units B are operated in a cooling mode, and which corresponds to a case in which a heating load at the side of the indoor units B is greater than a cooling load. A cooling-main simultaneous operation mode is a mode in which some of the plurality of indoor units B are operated in a heating mode, and the rest of the indoor units B are operated in a cooling mode, and which corresponds to a case in which a cooling load at the side of the indoor units B is greater than a heating load.

<FIG> is a diagram illustrating a flow of refrigerant when the outdoor unit illustrated in <FIG> is operated in a heating-only operation mode. <FIG> is a diagram illustrating a flow of refrigerant when the outdoor unit illustrated in <FIG> is operated in a heating-main simultaneous operation mode.

In the case in which all of the indoor units B perform the heating operation or the heating load at the side of the indoor units B is greater than the cooling load, the outdoor unit A performs the heating operation. Referring to <FIG>, during the heating operation, the outdoor unit A operates the first compressor <NUM> and the second compressor <NUM>, and the compressed refrigerant is supplied to the first four-way valve <NUM> through the refrigerant supply pipe <NUM>.

During the heating operation, the controller of the outdoor unit connects the <NUM>-<NUM> passage <NUM> and the <NUM>-<NUM> passage <NUM> of the first four-way valve <NUM>, without connecting the <NUM>-<NUM> passage <NUM> and the <NUM>-<NUM> passage <NUM>. Accordingly, compressed refrigerant supplied to the first four-way valve <NUM> is supplied to the indoor units B through the high-pressure pipe <NUM> to be condensed in the indoor units B, and the condensed refrigerant returns again to the outdoor unit A through the liquid line <NUM>.

The refrigerant in the liquid line <NUM> flows to the supercooler <NUM> and the supercooler-outdoor heat exchanger connection pipe <NUM>. By controlling an opening degree of the first outdoor expansion valve <NUM> and the second outdoor expansion valve <NUM>, liquid refrigerant may be expanded, and after the expanded refrigerant is expanded in the first outdoor heat exchanger <NUM> and the second outdoor heat exchanger <NUM>, the refrigerant may be supplied to the second four-way valve <NUM> through the second four-way valve pipe <NUM>.

The controller connects the <NUM>-<NUM> passage <NUM> and the <NUM>-<NUM> passage <NUM> of the second four-way valve <NUM>. Accordingly, the refrigerant supplied to the second four-way valve <NUM> may be supplied to the accumulator <NUM> through the third four-way valve pipe <NUM>. The accumulator <NUM> may separate the supplied refrigerant into liquid and gaseous refrigerants, and then may supply the separated gaseous refrigerant to the respective compressors <NUM> and <NUM> through the accumulator-compressor connection pipe <NUM>.

In the case in which all of the plurality of indoor units B perform the heating operation, the refrigerant does not flow through the low-pressure pipe <NUM> as illustrated in <FIG>. When the heating load and cooling load are required at the same time and the heating load is greater than the cooling load, refrigerant also flows through the low-pressure pipe <NUM> as illustrated in <FIG>.

Referring to <FIG>, the indoor units B performing the cooling operation expand the condensed refrigerant to cool the indoor air, and the evaporated refrigerant returns to the outdoor unit A through the low-pressure pipe <NUM>. The evaporated refrigerant, flowing through the low-pressure pipe <NUM>, returns to the accumulator <NUM> through the third four-way valve pipe <NUM>. The refrigerant evaporated in the outdoor heat exchanger <NUM> and the refrigerant evaporated in the indoor units B are joined to the third four-way valve pipe <NUM>.

The flow of refrigerant described above with reference to <FIG> also applies to the following description.

<FIG> is a diagram illustrating a flow of refrigerant when the outdoor unit illustrated in <FIG> is operated in a cooling-only operation mode. <FIG> is a diagram illustrating a flow of refrigerant when the outdoor unit illustrated in <FIG> is operated in a cooling-main simultaneous operation mode.

In the case in which all of the indoor units B perform the cooling operation or the cooling load at the side of the indoor units B is greater than the heating load, the outdoor unit A performs the heating operation. Referring to <FIG>, during the cooling operation, the outdoor unit A operates the first compressor <NUM> and the second compressor <NUM>, and the compressed refrigerant is supplied to the first four-way valve <NUM> through the refrigerant supply pipe <NUM>.

During the cooling operation, the controller of the outdoor unit connects the <NUM>-<NUM> passage <NUM> and the <NUM>-<NUM> passage <NUM> of the first four-way valve <NUM>, without connecting the <NUM>-<NUM> passage <NUM> and the <NUM>-<NUM> passage <NUM>. Accordingly, compressed refrigerant supplied to the <NUM>-<NUM> passage <NUM> is supplied to the second four-way valve <NUM> through the first four-way valve pipe <NUM>.

The controller of the outdoor unit connects the <NUM>-<NUM> passage <NUM> and the <NUM>-<NUM> passage <NUM> of the second four-way valve <NUM>, without connecting the <NUM>-<NUM> passage <NUM> and the <NUM>-<NUM> passage <NUM>. By controlling the outdoor unit in this manner, compressed refrigerant is supplied to the first outdoor heat exchanger <NUM> and the second outdoor heat exchanger <NUM> through the second four-way valve pipe <NUM>, and each of the first outdoor heat exchanger <NUM> and the second outdoor heat exchanger <NUM> condenses the compressed refrigerant.

The refrigerant, having passed through the first outdoor heat exchanger <NUM> and the second outdoor heat exchanger <NUM>, is supplied to the indoor units B by passing through the supercooler-outdoor heat exchanger connection pipe <NUM>, the supercooler <NUM>, and the liquid line <NUM>. The indoor units B, supplied with condensed refrigerant through the liquid line <NUM>, expands and evaporates the refrigerant to cool the indoor air. The refrigerant evaporated in the indoor units B returns to the outdoor unit A through the high-pressure pipe <NUM> and the low-pressure pipe <NUM>.

The refrigerant returning through the high-pressure pipe <NUM> flows to the accumulator <NUM> through the fourth four-way valve pipe <NUM>. The fourth four-way valve pipe <NUM> connects the <NUM>-<NUM> passage <NUM> of the first four-way valve <NUM> and the third four-way valve pipe <NUM>.

The refrigerant returning through the low-pressure pipe <NUM> flows to the accumulator <NUM> through the third four-way valve pipe <NUM>. The accumulator <NUM> separates the supplied refrigerant into liquid and gaseous refrigerants, and supplies the separated gaseous refrigerant to the respective compressors <NUM> and <NUM> through the accumulator-compressor connection pipe <NUM>.

When all the plurality of indoor units B perform the cooling operation, the refrigerant in the indoor units B returns through the high-pressure pipe <NUM> and the low-pressure pipe <NUM> as illustrated in <FIG>. By contrast, if the heating load and the cooling load are required at the same time and the cooling load is greater than the heating load, the refrigerant in the indoor units B returns only through the low-pressure pipe <NUM> as illustrated in <FIG>, unlike <FIG>, and the compressed refrigerant is supplied to the indoor units B through the high-pressure pipe <NUM>. In this case, the controller connects the <NUM>-<NUM> passage <NUM> and the <NUM>-<NUM> passage <NUM> of the first four-way valve <NUM>, and connects the <NUM>-<NUM> passage <NUM> and the <NUM>-<NUM> passage <NUM> of the second four-way valve <NUM>.

By using the control method, the flow of refrigerant through the fourth four-way valve pipe <NUM> illustrated in <FIG> is blocked. Accordingly, a portion of the compressed refrigerant supplied to the first four-way valve <NUM> is supplied to the second four-way valve <NUM> through the first four-way valve pipe <NUM>, and the remaining refrigerant is supplied to the first four-way valve <NUM>.

The compressed refrigerant supplied to the first four-way valve <NUM> is supplied to any one of the indoor units B through the high-pressure pipe <NUM> to provide heating. The refrigerant condensed in the indoor units B, which are supplied with the compressed refrigerant, may return to the outdoor unit A through the low-pressure pipe <NUM>.

<FIG> is a diagram illustrating a flow of refrigerant when the plurality of indoor units illustrated in <FIG> are operated in a heating-only operation mode. In the heating-only operation mode, both the indoor units B1 and B2 perform the heating operation. The heating-only operation mode will be described with reference to <FIG>.

The outdoor unit A performs the heating operation, and the high-pressure refrigerant supplied from the outdoor unit A is supplied to the indoor high-pressure pipe <NUM> through the high-pressure pipe <NUM>. The refrigerant supplied to the indoor high-pressure pipe <NUM> is supplied to the first indoor heat exchanger <NUM> through the indoor high-pressure bypass pipe <NUM>, and the first indoor heat exchanger <NUM> performs heat exchange between the air and refrigerant in the first indoor unit passage <NUM> to condense the refrigerant. The controller of the indoor units opens the high-pressure valve <NUM> and closes the low-pressure valve <NUM>.

The high-pressure refrigerant supplied from the outdoor unit A is supplied to the second indoor heat exchanger <NUM> through the high-pressure pipe <NUM> and the high-pressure valve-second indoor heat exchanger connection pipe <NUM>, and the second indoor heat exchanger <NUM> condenses the refrigerant by heat exchange between the air and refrigerant in the first indoor unit passage <NUM>. The air in the first indoor unit passage <NUM> may be indoor air bypassed through the indoor bypass passage <NUM> or may be outside air drawn in through the first inlet <NUM>.

The controller of the indoor units fully opens the first indoor expansion valve <NUM> and the second indoor expansion valve <NUM>, and causes the refrigerant, having passed through the first indoor heat exchange <NUM> and the second indoor heat exchanger <NUM>, to flow to the indoor supercooler <NUM>. The controller of the indoor units may selectively operate the indoor supercooler <NUM> by referring to indoor temperature and outdoor temperature.

During operation of the indoor supercooler <NUM>, a portion of the liquid refrigerant in the indoor supercooler-liquid line connection pipe <NUM> is bypassed to the indoor supercooling bypass pipe <NUM>, and is expanded through the indoor supercooling expansion valve <NUM>. The refrigerant expanded in the indoor supercooling expansion valve <NUM> may be heat-exchanged with the refrigerant passing through the indoor supercooling heat exchanger <NUM> to be evaporated, or may cool the refrigerant passing through the indoor supercooling heat exchanger <NUM>. Further, the refrigerant evaporated in the indoor supercooling heat exchanger <NUM> returns to the indoor low-pressure pipe <NUM> through the supercooler return line <NUM>.

The refrigerant having passed through the indoor supercooler <NUM> returns to the outdoor unit A through the indoor supercooler-liquid line connection pipe <NUM> and the liquid line <NUM>. The refrigerant flowing to the outdoor unit A through the liquid line <NUM> may be circulated by passing through the outdoor heat exchanger <NUM>, the second four-way valve <NUM>, and the accumulator <NUM> to flow to the compressors <NUM> and <NUM>.

<FIG> is a diagram illustrating a flow of refrigerant when the plurality of indoor units illustrated in <FIG> are operated in a cooling-only operation mode. In the cooling-only operation mode, both the indoor units B1 and B2 perform the cooling operation. The cooling-only operation mode will be described with reference to <FIG>.

The outdoor unit A performs the cooling operation, and refrigerant condensed through the liquid line <NUM> of the outdoor unit A is supplied to the plurality of indoor units B1 and B2. The refrigerant supplied through the liquid line <NUM> passes through the indoor supercooler-liquid line connection pipe <NUM>, the indoor supercooler <NUM>, and the second supercooler connection pipe <NUM>, to be supplied to the second indoor heat exchanger <NUM>. Liquid refrigerant is expanded in the second indoor expansion valve <NUM> disposed in the second supercooler connection pipe <NUM>, the expanded refrigerant is evaporated in the second indoor heat exchanger <NUM>, and the expanded refrigerant may cool the air in the first indoor unit passage <NUM>.

The controller of the indoor unit closes the high-pressure valve <NUM> and opens the low-pressure valve <NUM>. The refrigerant evaporated in the second indoor heat exchanger <NUM> may return to the low-pressure pipe <NUM> by passing through the low-pressure valve <NUM> and the indoor low-pressure pipe <NUM>.

If dehumidification is required in the indoor units B1 and B2, the first indoor heat exchanger <NUM> is operated, and the air cooled in the second indoor heat exchanger <NUM> may be heated in the first indoor heat exchanger <NUM>. In this case, the controller of the indoor units is supplied with the compressed refrigerant through the high-pressure pipe <NUM> and the indoor high-pressure pipe <NUM>, and as the high-pressure valve <NUM> is closed, the compressed refrigerant may be supplied to the first indoor heat exchanger <NUM> through the indoor high-pressure bypass pipe <NUM>.

The first indoor heat exchanger <NUM> condenses the compressed refrigerant, and the condensed refrigerant may flow to the first supercooler connection pipe <NUM>. In this case, the refrigerant flowing to the first supercooler connection pipe <NUM> may return to the second supercooler connection pipe <NUM> to join the refrigerant flowing to the second indoor heat exchanger <NUM>, and then may be evaporated in the second indoor heat exchanger <NUM>.

<FIG> is a diagram illustrating a flow of refrigerant when the plurality of indoor units illustrated in <FIG> are operated in a heating-main simultaneous operation. The heating-main simultaneous operation is performed when the heating load is greater than the cooling load, in which some of the plurality of indoor units B1 and B2 perform the heating operation and the rest of the indoor units perform the cooling operation.

The heating-main simultaneous operation will be described with reference to <FIG>. For convenience of explanation, the first indoor unit B1 performs the heating operation, and the second indoor unit B2 performs the cooling operation. The outdoor unit A performs the heating operation, and refrigerant of the compressors <NUM> and <NUM> is supplied through the high-pressure pipe <NUM> of the outdoor unit A.

The refrigerant supplied through the high-pressure pipe <NUM> is supplied to the first indoor heat exchanger <NUM> and the second heat exchanger <NUM> of the first indoor unit B1, and is supplied to the first indoor heat exchanger <NUM> of the second indoor unit B2. The operation of the first indoor unit B1, which performs the heating operation, is the same as the operation illustrated in <FIG>, and the operation of the second indoor unit B2, which performs the cooling operation, is the same as the operation illustrated in <FIG>. Accordingly, the controller of the first indoor unit B1, performing the heating operation, circulates the refrigerant by opening the high-pressure valve <NUM> and closing the low-pressure valve <NUM>.

By contrast, the controller of the second indoor unit B2, performing the cooling operation, circulates the refrigerant by closing the high-pressure valve <NUM> and opening the low-pressure valve <NUM>. A portion of the refrigerant condensed in the first indoor heat exchanger <NUM> and the second indoor heat exchanger <NUM> of the first indoor unit B1 may be evaporated in the outdoor heat exchanger <NUM> of the outdoor unit A through the indoor low-pressure pipe <NUM>, and the rest of the condensed refrigerant may flow toward the second indoor unit B2 to be evaporated. That is, the rest of the condensed refrigerant flows to the indoor low-pressure pipe <NUM> of the second indoor unit B2 and may be evaporated in the second indoor heat exchanger <NUM> of the second indoor unit B2. That is, after being used for the heating operation of the first indoor unit B1, the condensed refrigerant may be supplied to the second indoor unit B2 for the cooling operation thereof, such that efficiency may be improved.

The low-pressure refrigerant, having circulated through the first indoor unit B1 and the second indoor unit B2, returns to the low-pressure pipe <NUM> through the indoor low-pressure pipe <NUM>, and the liquid refrigerant returns to the liquid line <NUM> through the indoor supercooler-liquid line connection pipe <NUM>.

The cooling-main simultaneous operation is performed when the cooling load is greater than the heating load, in which some of the plurality of indoor units B1 and B2 perform the heating operation and the rest of the indoor units perform the cooling operation. The cooling-main simultaneous operation will be described with reference to <FIG>. For convenience of explanation, the first indoor unit B1 performs the heating operation, and the second indoor unit B2 performs the cooling operation.

The outdoor unit A performs the cooling operation, and a portion of the refrigerant, compressed by the compressors <NUM> and <NUM> of the outdoor unit A, is condensed in the outdoor heat exchanger <NUM> and then flows to the second indoor unit B2 through the liquid line <NUM>, and the rest of the compressed refrigerant flows to the first indoor unit B1 through the high-pressure pipe <NUM>. The operation of the first indoor unit B1, which performs the heating operation, is the same as the operation illustrated in <FIG>, and the operation of the second indoor unit B2, which performs the cooling operation, is the same as the operation illustrated in <FIG>. Accordingly, the controller of the first indoor unit B1, performing the heating operation, circulates the refrigerant by opening the high-pressure valve <NUM> and closing the low-pressure valve <NUM>.

By contrast, the controller of the second indoor unit B2, performing the cooling operation, circulates the refrigerant by closing the high-pressure valve <NUM> and opening the low-pressure valve <NUM>. The refrigerant, condensed in the first indoor unit B1, flows to the indoor low-pressure pipe <NUM> of the second indoor unit B2 through the indoor low-pressure pipe <NUM> and may be evaporated in the second indoor heat exchanger <NUM>.

That is, after being used for the heating operation of the first indoor unit B1, the condensed refrigerant may be supplied to the second indoor unit B2 for the cooling operation thereof, such that efficiency may be improved. The low-pressure refrigerant, having circulated through the second indoor unit B2, returns to the low-pressure pipe <NUM> through the indoor low-pressure pipe <NUM>.

Embodiments disclosed herein provide a multi-type air conditioner capable of ventilating indoor air and outside air, in which some of a plurality of indoor units may perform a cooling operation, and the rest of the indoor units may perform a heating operation. Embodiments disclosed herein further provide a multi-type air conditioner in which when some of a plurality of indoor units perform a cooling operation, and the rest of the indoor units perform a heating operation, waste heat from any one of the indoor units may be recovered. Embodiments disclosed herein have an advantage in that while having three pipes including a high-pressure pipe, a low-pressure pipe, and a liquid line, there is no need for an HR (Heat Recovery) unit, thereby allowing installation with significantly less difficulty.

The multi-type air conditioner according to embodiments disclosed herein have one or more of the following advantages.

First, in the multi-type air conditioner according to embodiments disclosed herein, three pipes including a high-pressure pipe, a low-pressure pipe, and a liquid line, are connected to a plurality of indoor units, in which some of the indoor units may be operated in a cooling mode and the others may be operated in a heating mode, and waste heat from the indoor units operated in the heating mode may be recovered to be used for the indoor units operated in the cooling mode.

Second, in the multi-type air conditioner according to embodiments disclosed herein, a first indoor heat exchanger and a second indoor heat exchanger are disposed in a first indoor unit passage and a second indoor heat exchanger operated in a cooling mode dehumidifies air flowing in the first indoor unit passage, and the first indoor heat exchanger operated in a heating mode heats the dehumidified air, such that air may be discharged at a similar temperature to the indoor air.

Third, in the multi-type air conditioner according to embodiments disclosed herein, a high-pressure valve connected to a high-pressure pipe and a low-pressure valve connected to a low-pressure pipe are connected to a second indoor heat exchanger, such that the second indoor heat exchanger may be operated in a cooling mode or a heating mode.

Fourth, in the multi-type air conditioner according to embodiments disclosed herein, while having three pipes including a high-pressure pipe, a low-pressure pipe, and a liquid line, there is no need for an HR unit, thereby allowing installation with significantly less difficulty.

Advantages of the embodiments disclosed herein are not limited to the aforesaid, and other advantages not described will be clearly understood by those skilled in the art from the description of the appended claims.

Embodiments of the disclosure are described herein with reference to cross-section illustrations that are schematic illustrations of idealized embodiments (and intermediate structures) of the disclosure. Thus, embodiments of the disclosure should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing.

Claim 1:
A multi-type air conditioner comprising:
an outdoor unit (A), a high-pressure pipe (<NUM>), a low-pressure pipe (<NUM>), and a liquid line (<NUM>);
a plurality of indoor units (B), each including a case (<NUM>) connected to the outdoor unit (A) through the high-pressure pipe (<NUM>), the low-pressure pipe (<NUM>), and the liquid line (<NUM>);
a first indoor heat exchanger (<NUM>) and a second indoor heat exchanger (<NUM>) disposed in the case (<NUM>);
a high-pressure valve (<NUM>) and an indoor high-pressure pipe (<NUM>) connecting the high-pressure valve (<NUM>) to the high-pressure pipe (<NUM>), the high-pressure valve (<NUM>) controlling a flow of refrigerant;
a low-pressure valve (<NUM>) and an indoor low-pressure pipe (<NUM>) connecting the low-pressure valve (<NUM>) to the low-pressure pipe (<NUM>), the low-pressure valve (<NUM>) controlling a flow of refrigerant;
an indoor high-pressure bypass pipe (<NUM>) connecting the indoor high-pressure pipe (<NUM>) and the first indoor heat exchanger (<NUM>); and
a connection pipe connecting the high-pressure valve (<NUM>) and the low-pressure valve (<NUM>) to the second indoor heat exchanger (<NUM>),
wherein the case (<NUM>) comprises:
a first inlet (<NUM>) through which outside air is drawn in;
a first outlet (<NUM>) through which air, having passed through the first indoor heat exchanger (<NUM>) and the second heat exchanger (<NUM>), is discharged into a room;
a second inlet (<NUM>) through which indoor air is drawn in;
a second outlet (<NUM>) through which the indoor air, drawn in through the second inlet (<NUM>), is discharged outside,
a first indoor unit passage (<NUM>) connecting the first inlet (<NUM>) and the first outlet (<NUM>);
wherein the first indoor heat exchanger (<NUM>) and the second indoor heat exchanger (<NUM>) are disposed on the first indoor unit passage (<NUM>), the first indoor heat exchanger (<NUM>) being disposed on the side of the first outlet (<NUM>), and the second indoor heat exchanger (<NUM>) being disposed on the side of the first inlet (<NUM>).