Air conditioner

Abstract

 An air conditioner which prevents high or low pressure gas bypass loss in the case of using a four-way valve (16a) for switching high or low pressure of a heat exchanger (14a) and a high or low pressure gas pipe (34) is provided. The air conditioner includes an indoor (40a, 40b, 40c) having an indoor heat exchanger (41a, 41b, 41c) and an outdoor (l0a) having a compressor (11a) and an outdoor heat exchanger (14a), the indoor (40a, 40b, 40c) and the outdoor (10a) being connected by a high or low pressure gas pipe (34) and a liquid pipe (30) for passing a refrigerant, the outdoor (10a) including a heat exchanger four-way valve (16a) which connects the outdoor heat exchanger (14a) to any one of a compressor discharge side and intake side, and a high or low pressure gas pipe four-way valve (13a) which connects the high or low pressure gas pipe to any one of a compressor discharge side and intake side, wherein the outdoor (10a) further includes a first capillary tube (61a) connecting a dead port of the high or low pressure gas pipe four-way valve and the heat exchanger, and a second capillary tube (62a) connecting a dead port of the heat exchanger four-way valve and the high or low pressure gas pipe.

Description

Background of the Invention

[0001] The present invention relates to a simultaneous cooling and heating multi-air conditioner including an outdoor and a plurality of indoors, in which by switching high or low pressure of a heat exchanger and a high or low pressure gas pipe, a certain indoor performs a cooling operation while the other indoors perform a heating operation.

[0002] Switch of a condenser/evaporator of an outdoor heat exchanger of a simultaneous cooling and heating multi-air conditioner, and switch of high pressure/low pressure of a high or low pressure gas pipe do not sometimes link with each other since cooling and heating are simultaneously operated, and the condenser/evaporator and the high pressure/low pressure have to be separately switched respectively. At such a time, switching is sometimes performed in such a way as with a three-way switching valve by using three portions of a less expensive four-way valve which is frequently used in freezing cycles, instead of a three-way valve and an electromagnetic valve.

[0003] More specifically, to the three ports out of the four ports of a four-way valve, connection is made so that any one of (A) a compressor discharge side piping system and (B) a compressor intake side piping system is connected to (C) an outdoor heat exchanger or a high or low pressure gas pipe, and (D) one remaining dead port is completely sealed in an unused state.

[0004] However, if the remaining dead port is completely sealed in an unused state in a four-way valve, a refrigerant entering from the other ports is condensed and accumulates in the dead port, and the circulating refrigerant becomes insufficient. Therefore, the dead port is connected to the compressor intake piping via a capillary tube, and thereby, accumulation of the refrigerant is prevented. As an example of using a four-way valve and a capillary tube for an outdoor heat exchanger, for example, JP-A-2005-337659 can be cited.

[0005] In JP-A-2005-337659, explaining with reference to the above described reference characters (A) to (D), the respective ports of a four-way switching valve (four-way valve) 613 are switched to the state shown by the broken line of Fig. 1 at the time of a heating operation to be in the state in which (C) an outdoor heat exchanger 612 is connected to (B) an intake side piping system of a compressor 611, and (A) the compressor discharge side piping system and (D) a remaining port of the switching valve 613 are connected. However, in this connection state, a high pressure gas refrigerant at the compressor discharge side is bypassed to the intake side of the compressor 611 via the switching valve 613 and a capillary tube 637. Therefore, the refrigerant circulation amount to the indoor reduces, and the capability reduces.

Brief Summary of the Invention

[0006] In view of the disadvantage of the above described conventional art, an object of the present invention is to provide an air conditioner which prevents performance reduction by preventing bypass loss of a refrigerant in a cooling operation, a heating operation and an operation of mainly carrying out heating, decreases bypass loss of a four-way valve when an outdoor heat exchanger is a condenser and a high or low pressure gas pipe is at a high pressure (at the time of an operation of mainly carrying out cooling), and enhances performance in all operation states.

[0007] In order to attain the above-described object, an air conditioner according to the present invention includes an indoor having an indoor heat exchanger and an outdoor having a compressor and an outdoor heat exchanger, the indoor and the outdoor being connected by a high or low pressure gas pipe and a liquid pipe for passing a refrigerant, the outdoor including a heat exchanger four-way valve which connects the outdoor heat exchanger to any one of a compressor discharge side and intake side, and a high or low pressure gas pipe four-way valve which connects the high or low pressure gas pipe to any one of a compressor discharge side and intake side, wherein the outdoor further includes a first capillary tube connecting a dead port of the high or low pressure gas pipe four-way valve and the heat exchanger, and a second capillary tube connecting a dead port of the heat exchanger four-way valve and the high or low pressure gas pipe.

[0008] In order to attain the above described object, an air conditioner according to the present invention includes an indoor having an indoor heat exchanger and an outdoor having a compressor and an outdoor heat exchanger, the indoor and the outdoor being connected by a high or low pressure gas pipe and a liquid pipe for passing a refrigerant, the outdoor including a heat exchanger four-way valve which connects the outdoor heat exchanger to any one of a compressor discharge side and intake side, and a high or low pressure gas pipe four-way valve which connects the high or low pressure gas pipe to any one of a compressor discharge side and intake side, wherein the high or low pressure gas pipe four-way valve has a high or low pressure gas pipe port, a high pressure port, a low pressure port and a dead port, the dead port and the heat exchanger being connected by a first capillary tube, and the heat exchanger four-way valve has a heat exchanger port, a high pressure port, a low pressure port and a dead port, the dead port and the high or low pressure gas pipe being connected by a second capillary tube.

[0009] Further, in the air conditioner, at a time of cooling operation, the refrigerant flows to the outdoor heat exchanger via the first capillary tube from the dead port of the high or low pressure gas pipe four-way valve, and a return refrigerant from the indoor flows to the compressor intake side from the dead port of the heat exchanger four-way valve via the second capillary tube.

[0010] Further, in the air conditioner, at a time of a heating operation, the refrigerant flows to the high or low pressure gas pipe side via the second capillary tube from the dead port of the heat exchanger four-way valve, and the return refrigerant from the outdoor flows to the compressor intake side from the dead port of the high or low pressure gas pipe four-way valve via the first capillary tube.

[0011] Further, an air conditioner according to the present invention including an indoor having an indoor heat exchanger and an outdoor having a compressor and an outdoor heat exchanger, the indoor and the outdoor being connected by a high or low pressure gas pipe and a liquid pipe for passing a refrigerant, the outdoor including a heat exchanger four-way valve which connects the outdoor heat exchanger to any one of a compressor discharge side and intake side, and a high or low pressure gas pipe four-way valve which connects the high or low pressure gas pipe to any one of a compressor discharge side and intake side, wherein the high or low pressure gas pipe four-way valve has a high or low pressure gas pipe port, a high pressure port, a low pressure port and a dead port, the dead port and the heat exchanger being connected by a first bypass valve for passing the refrigerant in a heat exchanger direction, and the heat exchanger four-way valve has a heat exchanger port, a high pressure port, a low pressure port and a dead port, and the dead port and the high or low pressure gas pipe being connected by a second bypass valve for passing the refrigerant in a high or low pressure gas pipe direction.

[0012] Further, in the air conditioner, the first bypass valve and second bypass valve are a first check-valve and a second check-valve respectively.

[0013] Further, in the air conditioner, at the time of a cooling operation, the refrigerant flows to the outdoor heat exchanger via the first check-valve from the dead port of the high or low pressure gas pipe four-way valve.

[0014] Further, in the air conditioner, at the time of a heating operation, the refrigerant flows to the high or low pressure gas pipe via the second check-valve from the dead port of the heat exchanger four-way valve.

[0015] Further, in the air conditioner, the first bypass valve and second bypass valve are both constituted of opening and closing valves, in the case of four-way valve switch in which the dead port of at least one of the four-way valves is connected to the compressor discharge side, the dead port of the four-way valve of the switch is opened, and in the case of four-way valve switch in which the dead ports of both the four-way valves are both connected to the compressor intake side, the opening and closing valves are both closed.

[0016] According to the present invention, when a switching operation of a cooling operation, a heating operation, and a simultaneous heating/cooling operation in a simultaneous cooling and heating multi-air conditioner is performed by using a less expensive four-way valve, bypass loss of a refrigerant is prevented, and the performance can be enhanced. Further, the liquid refrigerant which enters from the port of the four-way valve can be prevented from being condensed and accumulating in the dead port.

Brief Description of the Several Views of the Drawings

[0017] 

Fig. 1 is a freezing cycle schematic diagram according to embodiment 1 of the present invention;

Fig. 2 is a freezing cycle schematic diagram according to embodiment 2 of the present invention; and

Fig. 3 is a freezing cycle schematic diagram according to embodiment 3 of the present invention.

Detailed Description of the Invention

[0018] Hereinafter, embodiments of a simultaneous cooling and heating multi-air conditioner of the present invention will be described with reference to the drawings.

[Embodiment 1]

[0019] Fig. 1 is a schematic diagram of embodiment 1 of a freezing cycle of the simultaneous cooling and heating multi-air conditioner of the present invention. The air conditioner is constituted by connecting one outdoor 10a and three indoors 40a, 40b and 40c to a liquid pipe 30 for refrigerant, and a high or low pressure gas pipe 34 and a low pressure gas pipe 37 of a refrigerant in parallel respectively. Here, the number of outdoors which are connected may be larger than one, and the number of indoors which are connected may be larger or smaller than three, or may be one.

[0020] As shown in the drawing, the inside of a casing of the outdoor 10a includes a compressor 11a which compresses and discharges a refrigerant, a check-valve 12a for passing the refrigerant discharged from the compressor 11a in a discharge direction, four-way valves 16a and 13a which switch a circulating direction of the refrigerant, an outdoor heat exchanger 14a which performs heat exchange between the refrigerant and external air, an outdoor fan 19a which blows the external air to the outdoor heat exchanger 14a, and an outdoor expansion valve 15a which functions as a throttling mechanism. Here, the four-way valve 16a is called a heat exchanger four-way valve, and the four-way valve 13a is called a high or low pressure gas pipe four-way valve. Of four ports of the four-way valves, a port connected to a high pressure side of a compressor discharge side piping 21a is called a high pressure port, a port connected to a low pressure side of a compressor intake side piping 23a is called a low pressure port, a port connected to a high or low pressure gas pipe is called a high or low pressure gas pipe port, a port connected to a heat exchanger is called a heat exchanger port, and a remaining port is called a dead port.

[0021] Accordingly, the high or low pressure gas pipe four-way valve 13a has the respective ports for the high or low pressure gas pipe, high pressure and low pressure, and the dead port, whereas the heat exchanger four-way valve 16a has the respective ports for the heat exchanger, the high pressure and the low pressure, and the dead port.

[0022] The inside of the casing of the outdoor 10a further includes a bypass capillary tube (first capillary tube) 61a which is connected to between the dead port of the high or low pressure gas pipe four-way valve 13a and the outdoor heat exchanger 14a, and a bypass capillary tube (second capillary tube) 62a which is connected to between the dead port of the heat exchanger four-way valve 16a and the high or low pressure gas pipe (a gate valve 32a side). The other end of the outdoor expansion valve 15a is connected to the liquid pipe 30 via a liquid gate valve 31a. The low pressure side of the high or low pressure gas pipe four-way valve 13a is connected to the high or low pressure gas pipe 34 via the high or low pressure gate valve 32a. The compressor intake side piping 23a is connected to the low pressure gas pipe 37 via a low pressure gas gate valve 39a. The respective gate valves 31a, 32a and 39a are opened when the outdoor 10a is connected to the respective pipes 30, 34 and 37, and is kept open, for example, during an operation after that.

[0023] The respective casings of the indoors 40a, 40b and 40c house indoor heat exchangers 41a, 41b and 41c which perform heat exchange between the refrigerant and indoor air, indoor expansion valves 42a, 42b, and 42c which are connected to between the liquid pipe 30 and the respective indoor heat exchangers, and cooling and heating switch units 50a, 50b and 50c. High pressure side opening and closing mechanisms 51a, 51b and 51c which are connected to between the high or low pressure gas pipe 34 and the respective indoor heat exchangers, and low pressure side opening and closing mechanisms 52a, 52b and 52c which are connected to between the low pressure gas pipe 37 and the respective indoor heat exchangers are housed in the cooling and heating switch units 50a, 50b and 50c.

[0024] In the air conditioner constituted as described above, a control device (not illustrated) is provided, which performs switch control of the high or low pressure gas pipe four-way valve 13a and the heat exchanger four-way valve 16a of the outdoor 10a, and switch control of the high pressure side opening and closing mechanisms 51a, 51b and 51c, and the low pressure side opening and closing mechanisms 52a, 52b and 52c in the indoors 40a, 40b and 40c based on an operation signal from the operation device operated by a man or a temperature sensor (both not illustrated).

[0025] Next, an operation at the time of a cooling operation of the outdoor 10a and the indoors 40a, 40b and 40c will be described. The high or low pressure gas pipe four-way valve 13a and the heat exchanger four-way valve 16a are in a connected state shown by the solid line in Fig. 1. In the high or low pressure gas pipe four-way valve 13a, the low pressure port and the high or low pressure gas pipe 34 are connected, and the high pressure port and the dead port are connected so that the high pressure port is connected to the outdoor heat exchanger 14a via the bypass capillary tube 61a. In the heat exchanger four-way valve 16a, the outdoor heat exchanger 14a and the high pressure port are connected, and the low pressure port and the dead port are connected so that the low pressure port is connected to the high or low pressure gate valve 32a side via the bypass capillary tube 62a.

[0026] As the flow of the refrigerant, the high pressure gas refrigerant compressed in the compressor 11a is fed to the high or low pressure gas pipe four-way valve 13a and the heat exchanger four-way valve 16a. The high pressure gas refrigerant which is fed to the high or low pressure gas pipe four-way valve 13a is fed to the outdoor heat exchanger 14a via the bypass capillary tube 61a, and the high pressure gas refrigerant which is fed to the heat exchanger four-way valve 16a is also fed to the outdoor heat exchanger 14a. The main flow of the high pressure gas refrigerant passes through the four-way valve 16a, but the flow also occurs to the bypass capillary tube 61a. Therefore, the high pressure gas refrigerant is not excessively condensed in the dead port of the high or low pressure gas pipe side four-way valve 13a, and the liquid refrigerant does not accumulate therein. Further, a bypass between high and low pressures is not formed by the bypass capillary tube 61a.

[0027] The high pressure gas refrigerant fed to the outdoor heat exchanger 14a exchanges heat with outdoor air and condenses to be a high pressure refrigerant, passes through the liquid gate valve 31a and the liquid pipe 30, and is used for a cooling operation in the respective indoors 40a, 40b and 40c to be a low pressure gas refrigerant. A return refrigerant of low pressure gas flowing out of each of the indoors is diverted to the high or low pressure gas pipe 34 and the low pressure gas pipe 37 to return to the outdoor. A part of the low pressure gas refrigerant of the high or low pressure gas pipe 34 is fed to the dead port of the heat exchanger four-way valve 16a via the bypass capillary tube 62a, and the remainder is fed to the high or low pressure gas pipe four-way valve 13a. The low pressure gas refrigerants which are fed to the heat exchanger four-way valve 16a and the high or low pressure gas pipe four-way valve 13a merge in the piping 23a and are fed to the compressor. The low pressure gas refrigerant of the low pressure gas pipe 37 is also fed to the compressor and compressed again. The bypass capillary tube 62a of the heat exchanger four-way valve 16a is connected to the low pressure port via the dead port, and the refrigerant does not condense or does not accumulate in the four-way valve. Further, the bypass between high and low pressures is not formed by the bypass capillary tube 62a.

[0028] Next, an operation at the time of a heating operation of the outdoor 10a, and the indoors 40a, 40b and 40c will be described. Concerning the operation of mainly carrying out heating in which a cooling machine is partially included in the heating indoors, the flow of the refrigerant around the four-way valve is the same as that in the heating operation, and therefore, the description will be omitted.

[0029] At the time of a heating operation, the high or low pressure gas pipe four-way valve 13a and the heat exchanger four-way valve 16a are in the connected state shown by the broken line in Fig. 1. In the high or low pressure gas pipe four-way valve 13a, the high or low pressure gas pipe 34 and the high pressure port are connected, and the low pressure port and the dead port are connected so that the low pressure port is connected to the outdoor heat exchanger 14a via the bypass capillary tube 61a. In the heat exchanger four-way valve 16a, the outdoor heat exchanger 14a and the low pressure port are connected, the high pressure port and the dead port are connected, and the high pressure port is connected to the high or low pressure gate valve 32a side via the bypass capillary tube 62a.

[0030] As the flow of the refrigerant, the high pressure gas refrigerant compressed in the compressor 11a is fed to the high or low pressure gas pipe four-way valve 13a and the heat exchanger four-way valve 16a. The high pressure gas refrigerant which is fed to the high or low pressure gas pipe four-way valve 13a is fed to the high or low pressure gas pipe 34, and the high pressure gas refrigerant which is fed to the heat exchanger four-way valve 16a is similarly fed to the high or low pressure gas pipe 34 via the bypass capillary tube 62a. The main flow of the high pressure gas refrigerant passes through the four-way valve 13a, but the flow also occurs to the bypass capillary tube 62a. Therefore, the high pressure gas refrigerant does not excessively condense in the dead port of the heat exchanger four-way valve 16a, and the liquid refrigerant does not accumulate therein. Further, the bypass between high and low pressures is not formed by the bypass capillary tube 62a.

[0031] The high pressure gas refrigerant which is fed to the high or low pressure gas pipe 34 is used for a heating operation in each of the indoors 40a, 40b and 40c and condenses to be a high pressure liquid refrigerant. The high pressure liquid refrigerant passes through the liquid pipe 30, is restricted by the outdoor expansion valve 15a, and exchanges heat with the outdoor air in the outdoor heat exchanger 14a to be a return refrigerant of a low pressure gas. A part of the low pressure gas refrigerant is fed to the dead port of the high or low pressure gas pipe four-way valve 13a via the bypass capillary tube 61a, and the remainder is fed to the heat exchanger four-way valve 16a. The low pressure gas refrigerants which are fed to the high or low pressure gas pipe four-way valve 13a and the heat exchanger four-way valve 16a merge in the piping 23a and are fed to the compressor to be compressed again. The bypass capillary tube 61a of the heat exchanger four-way valve 13a is connected to the low pressure port via the dead port, and the refrigerant is not condensed or accumulated in the four-way valve. Further, a bypass between high and low pressures is not formed by the bypass capillary tube 61a.

[0032] Finally, the case of an operation of mainly carrying out cooling in which the outdoor 10a, and the indoors 40a and 40b perform a cooling operation while the indoor 40c performs a heating operation will be described. In Fig. 1, the high or low pressure gas pipe four-way valve 13a is in the connected state shown by the broken line, and the heat exchanger four-way valve 16a is in the connected state shown by the solid line.

[0033] In the high or low pressure gas pipe four-way valve 13a, the high or low pressure gas pipe 34 and the high pressure port are connected, and in the heat exchanger four-way valve 16a, the outdoor heat exchanger 14a and the high pressure port are connected. Here, the low pressure side of the high or low pressure gas four-way valve 13a is connected to the outdoor heat exchanger 14a and the high pressure port of the heat exchanger four-way valve 16a via the dead port and the bypass capillary tube 61a. The dead port of the heat exchanger four-way valve 16a is connected to the high or low pressure gas gate valve 32a side and the low pressure port via the bypass capillary tube 62a.

[0034] As the flow of the refrigerant, the high pressure gas refrigerant compressed in the compressor 11a is fed to the high or low pressure gas pipe four-way valve 13a and the heat exchanger four-way valve 16a. The high pressure gas refrigerant which is fed to the high or low pressure gas pipe four-way valve 13a is fed to the high or low pressure gas pipe 34, and the high pressure gas refrigerant which is fed to the heat exchanger four-way valve 16a is fed to the outdoor heat exchanger 14a. Here, a part of the high pressure gas refrigerant which is fed to the outdoor heat exchanger 14a is fed to the compressor intake piping 23a via the bypass capillary tube 61a, the dead port of the high or low pressure gas pipe four-way valve 13a, and the low pressure port.

[0035] Similarly, a part of the high pressure gas refrigerant which is fed to the high or low pressure gas pipe 34 via the high or low pressure gas pipe four-way valve 13a is fed to the compressor intake piping 23a via the bypass capillary tube 62a, the dead port and the low pressure port of the heat exchanger four-way valve 16a. The flow of the refrigerant occurs in the bypass capillary tubes 61a and 62a, and therefore, the liquid refrigerant does not accumulate in the high or low pressure gas pipe four-way valve 13a and the heat exchanger four-way valve 16a, but since the bypass between high and low pressures is formed by passing through both the bypass capillary tubes, the refrigerant circulation amount is decreased by the amount for the bypass to reduce performance. However, since an exhaust heat recovery operation of the indoors is carried out in the simultaneous cooling and heating operation, a reserve capacity occurs to the outdoor capacity, and capability shortage does not occur.

[0036] The high pressure gas refrigerant which is fed to the high or low pressure gas pipe 34 is used for a heating operation in the indoor 40c to become a condensed high pressure liquid refrigerant. Further, the high pressure gas refrigerant which is fed to the outdoor heat exchanger 14a exchanges heat with outdoor air and condenses to become a high pressure liquid refrigerant, passes through the liquid gate valve 31a and the liquid pipe 30, merges with the liquid refrigerant which is condensed in the indoor 40c, is used for the cooling operation in the indoors 40a and 40b and becomes a low pressure gas refrigerant. The low pressure gas refrigerant which flows out of each of the indoors passes through the low pressure gas pipe 37, returns to the compressor and is compressed again.

[0037] In the present embodiment, the bypass capillary tube is used for the dead port of the four-way valve, and therefore, the following effect is provided. More specifically, the bypass is such that the liquid refrigerant does not accumulate in the four-way valve, and therefore, a fine pipe can be used, which is far less expensive as compared with the other electromagnetic valves and the like. Further, the bypass capillary tube does not have the operating component as compared with the other valves and the like. Therefore, operation failure (tightened) does not occur, and is highly reliable.

[Embodiment 2]

[0038] Fig. 2 is a schematic diagram of a freezing cycle of embodiment 2 of the present invention. This is an example in which the bypass capillary tubes 61a and 62a shown in Fig. 1 are changed to a first bypass check-valve (first bypass valve) 63a and a second bypass check-valve (second bypass valve) 64a. Here, the first bypass check-valve (first bypass valve) 63a is connected so that the refrigerant flows in the heat exchanger direction between the dead port of the high or low pressure gas pipe four-way valve 13a and the heat exchanger 14a. The second bypass check-valve (second bypass valve) 64a is connected so that the refrigerant flows in the high or low pressure gas pipe direction between the dead port of the heat exchanger four-way valve 16a and the high or low pressure gas pipe 34.

[0039] First, the case of a cooling operation of the outdoor 10a, and the indoors 40a, 40b and 40c will be described. The high or low pressure gas pipe four-way valve 13a and the heat exchanger four-way valve 16a are in the connected state shown by the solid line in Fig. 2. In the high or low pressure gas pipe four-way valve 13a, the high or low pressure gas pipe 34 is connected to the low pressure port, and in the heat exchanger four-way valve 16a, the outdoor heat exchanger 14a is connected to the high pressure port. The high pressure port of the high or low pressure gas pipe four-way valve 13a is connected to the outdoor heat exchanger 14a via the first bypass check-valve 63a, and the low pressure port of the heat exchanger four-way valve 16a is connected to the high or low pressure gate valve 32a side via the second bypass check-valve 64a.

[0040] As the flow of the refrigerant, the high pressure gas refrigerant compressed in the compressor 11a is fed to the high or low pressure gas pipe four-way valve 13a and the heat exchanger four-way valve 16a. The high pressure gas refrigerant which is fed to the high or low pressure gas pipe four-way valve 13a is fed to the outdoor heat exchanger 14a via the bypass check-valve 63a, and the high pressure gas refrigerant which is fed to the heat exchanger four-way valve 16a is also fed to the outdoor heat exchanger 14a. The flow of the refrigerant occurs by the bypass check-valve 63a. Therefore, the high pressure gas refrigerant is not excessively condensed in the dead port of the high or low pressure gas pipe four-way valve 13a, and the liquid refrigerant does not accumulate therein. Further, a bypass between high and low pressures is not formed by the bypass check-valve 63a.

[0041] The high pressure gas refrigerant which is fed to the outdoor heat exchanger 14a exchanges heat with outdoor air and condenses to be a high pressure liquid refrigerant, passes through the liquid gate valve 31a and the liquid pipe 30, and is used for a cooling operation in the indoors 40a, 40b and 40c to be a low pressure gas refrigerant. A return refrigerant of low pressure gas which flows out of each of the indoors is diverted to the high or low pressure gas pipe 34 and the low pressure gas pipe 37 to return to the outdoor. The low pressure gas refrigerant of the high or low pressure gas pipe 34 is fed to the high or low pressure gas pipe four-way valve 13a. The low pressure gas refrigerant is not fed to the heat exchanger four-way valve 16a, since the bypass check-valve 64a of the dead port is in the opposite direction. However, the bypass check-valve 64a of the heat exchanger four-way valve 16a is connected to the low pressure gas refrigerant side. Thus, the refrigerant of the dead port does not accumulate in the four-way valve by being condensed, and further, the bypass check-valve 64a does not form a bypass between high and low pressures. The low pressure gas refrigerant which is fed to the high or low pressure gas pipe four-way valve 13a is fed to the compressor, and the low pressure gas refrigerant of the low pressure gas pipe 37 is also fed to the compressor, which are compressed again.

[0042] Next, the case of a heating operation of the outdoor 10a and the indoors 40a, 40b and 40c will be described. The high or low pressure gas pipe four-way valve 13a and the heat exchanger four-way valve 16a are in the connected state shown by the broken line in Fig. 2. In the high or low pressure gas pipe four-way valve 13a, connection is in the direction in which the high or low pressure gas pipe 34 is connected to the high pressure port, and in the heat exchanger four-way valve 16a, connection is in the direction in which the outdoor heat exchanger 14a is connected to the low pressure port. The low pressure port of the high or low pressure gas pipe four-way valve 13a is connected to the outdoor heat exchanger 14a via the dead port and the bypass check-valve 63a, and the high pressure port of the heat exchanger four-way valve 16a is connected to the high or low pressure gate valve 32a side via the dead port and the bypass check-valve 64a.

[0043] As the flow of the refrigerant, the high pressure gas refrigerant compressed in the compressor 11a is fed to the high or low pressure gas pipe four-way valve 13a and the heat exchanger four-way valve 16a. The high pressure gas refrigerant which is fed to the high or low pressure gas pipe four-way valve 13a is fed to the high or low pressure gas pipe 34, and the high pressure gas refrigerant which is fed to the heat exchanger four-way valve 16a is also fed to the high or low pressure gas pipe 34 via the bypass check-valve 64a. The flow of the refrigerant occurs by the bypass check-valve 64a. Therefore, the high pressure gas refrigerant is not excessively condensed in the dead port of the heat exchanger four-way valve 16a, and the liquid refrigerant does not accumulate therein. Further, a bypass between high and low pressures is not formed.

[0044] The high pressure gas refrigerant which is fed to the high or low pressure gas pipe 34 is used for a heating operation in each of the indoors 40a, 40b and 40c, and is condensed to be a high pressure liquid refrigerant. Subsequently, the high pressure liquid refrigerant passes through the liquid pipe 30, is restricted in the outdoor expansion valve 15a, exchanges heat with outdoor air in the outdoor heat exchanger 14a to become a low pressure gas refrigerant, and is fed to the heat exchanger four-way valve 16a. The low pressure gas refrigerant is not fed to the dead port of the high or low pressure gas pipe four-way valve 13a, since the bypass check-valve 63a is in the opposite direction. However, the bypass check-valve 63a of the high or low pressure gas pipe four-way valve 13a is connected to the low pressure at the low pressure gas refrigerant side. Thus, the refrigerant does not condense in the dead port, or does not accumulate in the four-way valve, or a bypass between high and low pressures is not formed. The low pressure gas refrigerant which is fed to the heat exchanger four-way valve 16a is fed to the compressor 11a, and is compressed again.

[0045] Finally, the case of performing an operation of mainly carrying out cooling in which the outdoor 10a, and the indoors 40a and 40b perform a cooling operation while the indoor 40c performs a heating operation will be described. In Fig. 2, the high or low pressure gas pipe four-way valve 13a is in the connected state shown by the broken line, and the heat exchanger four-way valve 16a is in the connected state shown by the solid line. In the high or low pressure gas pipe four-way valve 13a, connection is in the direction in which the high or low pressure gas pipe 34 is connected to the high pressure port, and in the heat exchanger four-way valve 16a, connection is in the direction in which the outdoor heat exchanger 14a is connected to the high pressure port. Here, the low pressure port of the high or low pressure gas pipe four-way valve 13a is connected to the outdoor heat exchanger 14a via the dead port and the bypass check-valve 63a. The low pressure port of the heat exchanger four-way valve 16a is connected to the high or low pressure gas gate valve 32a side via the dead port and the bypass check-valve 64a.

[0046] As the flow of the refrigerant around the four-way valve, the high pressure gas refrigerant compressed by the compressor 11a is fed to the high or low pressure gas pipe four-way valve 13a and the heat exchanger four-way valve 16a. The high pressure gas refrigerant which is fed to the high or low pressure gas pipe four-way valve 13a is fed to the high or low pressure gas pipe 34, and the high pressure gas refrigerant which is fed to the heat exchanger four-way valve 16a is fed to the outdoor heat exchanger 14a.

[0047] Here, high pressure is exerted on the bypass check-valve 63a, but since the direction is opposite, the refrigerant is not fed to the high or low pressure gas pipe four-way valve 13a and the compressor intake piping 23a. Similarly, high pressure is also exerted on the bypass check-valve 64a, but since the direction is opposite, the refrigerant is not fed to the heat exchanger four-way valve 16a and the compressor intake piping 23a. Thereby, a bypass between high and low pressures at the time of the operation of mainly carrying out cooling, which occurs to the aforementioned embodiment 1 of Fig. 1 can be prevented.

[0048] Further, the pressure between the dead port of the high or low pressure gas pipe four-way valve 13a from the check-valve, and the pressure between the dead port of the heat exchanger four-way valve 16a and the check-valve are drawn to low pressure. Therefore, the refrigerant is prevented from being condensed and accumulating in the dead port of each of the four-way valves, or a bypass between high and low pressures is not formed.

[Embodiment 3]

[0049] Fig. 3 is a schematic diagram of a freezing cycle of embodiment 3 of the present invention. Fig. 3 is an example in which the first bypass check-valve 63a and the second bypass check-valve 64a shown in Fig. 2 are changed to a first bypass opening and closing valve 65a and a second bypass opening and closing valve 66a respectively.

[0050] The first bypass opening and closing valve (first bypass valve) 65a is opened and closed so that the refrigerant flows in the heat exchanger direction between the dead port of the high or low pressure gas pipe four-way valve 13a and the heat exchanger 14a, and the second bypass opening and closing valve (second bypass valve) 66a is opened and closed so that the refrigerant flows in the high or low pressure gas pipe direction between the dead port of the heat exchanger four-way valve 16a and the high or low pressure gas pipe 34. The opening and closing valve may be an electromagnetic valve or an expansion valve. The bypass opening and closing valve is characterized by being usually in an open state, and being brought into a closed state when the outdoor heat exchanger 14a is an evaporator, and when the high or low pressure gas pipe 34 is at low pressure (especially at the time of the operation of mainly carrying out cooling). Thereby, as in Fig. 2 of embodiment 2, the bypass between high and low pressures at the time of the operation of mainly carrying out cooling which occurs in Fig. 1 can be prevented.

[0051] First, the case of the operation of carrying out cooling of the outdoor 10a, and the indoors 40a, 40b and 40c will be described. The high or low pressure gas pipe four-way valve 13a and the heat exchanger four-way valve 16a are in the connected state shown by the solid line in Fig. 3. In the high or low pressure gas pipe four-way valve 13a, connection is in the direction in which the high or low pressure gas pipe 34 is connected to the low pressure port, and in the heat exchanger four-way valve 16a, connection is in the direction in which the outdoor heat exchanger 14a is connected to the high pressure port. Here, the high pressure port of the high or low pressure gas pipe four-way valve 13a is connected to the outdoor heat exchanger 14a via the dead port and the bypass opening and closing valve 65a. The low pressure port of the heat exchanger four-way valve 16a is connected to the high or low pressure gate valve 32a side via the dead port and the bypass opening and closing valve 66a. At this time, the bypass opening and closing valve 65a is necessarily opened, but the bypass opening and closing valve 66a may be opened or closed.

[0052] As the flow of the refrigerant, the high pressure gas refrigerant compressed in the compressor 11a is fed to the high or low pressure gas pipe four-way valve 13a and the heat exchanger four-way valve 16a. The high pressure gas refrigerant which is fed to the high or low pressure gas pipe four-way valve 13a is fed in the direction of the outdoor heat exchanger 14a since the bypass opening and closing valve 65a is open, and the high pressure gas refrigerant which is fed to the heat exchanger four-way valve 16a is also fed to the outdoor heat exchanger 14a. The flow of the refrigerant occurs by the open state of the bypass opening and closing valve 65a. Therefore, the high pressure gas refrigerant is not excessively condensed in the dead port of the high or low pressure gas pipe four-way valve 13a, and the liquid refrigerant does not accumulate therein. Further, a bypass between high and low pressures is not formed.

[0053] The high pressure gas refrigerant which is fed to the outdoor heat exchanger 14a exchanges heat with outdoor air and condenses to be a high pressure refrigerant, passes through the liquid gate valve 31a and the liquid pipe 30, and is used for a cooling operation in the indoors 40a, 40b and 40c to be a low pressure gas refrigerant. A return refrigerant of low pressure gas which flows out of each of the indoors is diverted to the high or low pressure gas pipe 34 and the low pressure gas pipe 37 to return to the outdoor. The low pressure gas refrigerant of the high or low pressure gas pipe 34 is fed to the high or low pressure gas pipe four-way valve 13a. The bypass opening and closing valve 66a may be opened or closed to the heat exchanger four-way valve 16a, and therefore, the refrigerant may be fed or not fed.

[0054] Piping (including the dead port) between the low pressure port of the heat exchanger four-way valve 16a and the bypass opening and closing valve 66a is connected to the low pressure gas refrigerant side. Therefore, the refrigerant is not condensed in the dead port, or does not accumulate in the four-way valve. Further, a bypass between high and low pressures is not formed. The low pressure gas refrigerant which is fed to the high or low pressure gas pipe four-way valve 13a is fed to the compressor. The low pressure gas refrigerant of the low pressure gas pipe 37 is also fed to the compressor, and is compressed again.

[0055] Next, the case of a heating operation of the outdoor 10a and the indoors 40a, 40b and 40c will be described. The high or low pressure gas pipe four-way valve 13a and the heat exchanger four-way valve 16a are in the connected state shown by the broken line in Fig. 3. In the high or low pressure gas pipe four-way valve 13a, connection is in the direction in which the high or low pressure gas pipe 34 is connected to the high pressure port, and in the heat exchanger four-way valve 16a, connection is in the direction in which the outdoor heat exchanger 14a is connected to the low pressure port. Here, the low pressure port of the high or low pressure gas pipe four-way valve 13a is connected to the outdoor heat exchanger 14a via the bypass opening and closing valve 65a. The high pressure port of the heat exchanger four-way valve 16a is connected to the high or low pressure gate valve side via the bypass opening and closing valve 66a. The bypass opening and closing valve 66a is necessarily opened, but the bypass opening and closing valve 65a may be opened or closed.

[0056] As the flow of the refrigerant, the high pressure gas refrigerant compressed in the compressor 11a is fed to the high or low pressure gas pipe four-way valve 13a and the heat exchanger four-way valve 16a. The high pressure gas refrigerant which is fed to the high or low pressure gas pipe four-way valve 13a is fed to the high or low pressure gas pipe 34, and the high pressure gas refrigerant which is fed to the heat exchanger four-way valve 16a is fed to the high or low pressure gas pipe 34 since the bypass opening and closing valve 66a is opened. The flow of the refrigerant occurs by the bypass opening and closing valve 66a. Therefore, the high pressure gas refrigerant is not excessively condensed in the dead port of the heat exchanger four-way valve 16a, and the liquid refrigerant does not accumulate therein. A bypass between high and low pressures is not formed.

[0057] The high pressure gas refrigerant which is fed to the high or low pressure gas pipe 34 is used for a heating operation in each of the indoors 40a, 40b and 40c, and is condensed to be a high pressure liquid refrigerant. Subsequently, the high pressure liquid refrigerant passes through the liquid pipe 30, is restricted in the outdoor expansion valve 15a, exchanges heat with outdoor air through the outdoor heat exchanger 14a to become a low pressure gas refrigerant, and is fed to the heat exchanger four-way valve 16a. The refrigerant may be fed or may not be fed to the high or low pressure gas pipe four-way valve 13a, since the bypass opening and closing valve 65a may be opened or closed. The dead port between the high or low pressure gas pipe four-way valve 13a and the bypass opening and closing valve 65a is connected to the low pressure gas refrigerant side. Thus, the refrigerant is not condensed in the dead port, or does not accumulate in the four-way valve. Further, a bypass between high and low pressures is not formed. The low pressure gas refrigerant which is fed to the heat exchanger four-way valve 16a is fed to the compressor, and is compressed again.

[0058] Finally, the case of performing an operation of mainly carrying out cooling in which the outdoor 10a, and the indoors 40a and 40b perform a cooling operation while the indoor 40c performs a heating operation will be described. In Fig. 3, the high or low pressure gas pipe four-way valve 13a is in the connected state shown by the broken line, and the heat exchanger four-way valve 16a is in the connected state shown by the solid line. In the high or low pressure gas pipe four-way valve 13a, connection is in the direction in which the high or low pressure gas pipe 34 is connected to the high pressure port, and in the heat exchanger four-way valve 16a, connection is in the direction in which the outdoor heat exchanger 14a is connected to the high pressure port. Here, the low pressure side of the high or low pressure gas pipe four-way valve 13a is connected to the outdoor heat exchanger 14a via the bypass opening and closing valve 65a. The low pressure side of the heat exchanger four-way valve 16a is connected to the high or low pressure gas gate valve 32a side via the bypass opening and closing valve 66a. The bypass opening and closing valves 65a and 66a are both closed.

[0059] As the flow of the refrigerant around the four-way valve, the high pressure gas refrigerant compressed in the compressor 11a is fed to the high or low pressure gas pipe four-way valve 13a and the heat exchanger four-way valve 16a. The high pressure gas refrigerant which is fed to the high or low pressure gas pipe four-way valve 13a is fed to the high or low pressure gas pipe 34, and the high pressure gas refrigerant which is fed to the heat exchanger four-way valve 16a is fed to the outdoor heat exchanger 14a. Here, high pressure is exerted on the bypass opening and closing valve 65a, but since the bypass opening and closing valve 65a is closed, the refrigerant is not fed to the high or low pressure gas pipe four-way valve 13a and the compressor intake piping 23a. Similarly, high pressure is also exerted on the bypass opening and closing valve 66a, but since the bypass opening and closing valve 66a is closed, the refrigerant is not fed to the heat exchanger four-way valve 16a and the compressor intake piping 23a. Further, the pressure between the respective opening and closing valves and the high or low pressure gas pipe four-way valve 13a and the heat exchanger four-way valve 16a via the respective dead ports are drawn to low pressure. Therefore, the refrigerant is not condensed to accumulate in the four-way valves. Further, a bypass between high and low pressures is not formed.

Claims

1. An air conditioner comprising: an indoor (40a, 40b, 40c) including an indoor heat exchanger (41a, 41b, 41c), an outdoor (10a) including an outdoor heat exchanger (14a) and a compressor (11a) for compressing a refrigerant, a liquid pipe (30) through which the refrigerant liquefied by one of the outdoor heat exchanger (14a) and the indoor heat exchanger (41a, 41b, 41c) is enabled to flow from the one of the outdoor heat exchanger (14a) and the indoor heat exchanger (41a, 41b, 41c) to the other one of the outdoor heat exchanger (14a) and the indoor heat exchanger (41a, 41b, 41c), and a high or low pressure gas pipe (34) through which the refrigerant is enabled to flow between the compressor (11a) and the indoor heat exchanger (41a, 41b, 41c) while being prevented from passing through the outdoor heat exchanger (14a),
wherein the outdoor (10a) further includes:

a first four-way valve (16a) including a first high pressure port through which the compressed refrigerant is enabled to be taken from the compressor (11a) into the first four-way valve (16a), a first low pressure port through which the refrigerant is enabled to be taken from the first four-way valve (16a) into the compressor (11a), a heat exchanger port through which the refrigerant is enabled to flow between the outdoor heat exchanger (14a) and the compressor (11a), and a first dead port fluidly connected to the first high pressure port when the refrigerant flows from the heat exchanger port to the first low pressure port and fluidly connected to the first low pressure port when the refrigerant flows from the first high pressure port to the heat exchanger port,

a second four-way valve (13a) including a second high pressure port through which the compressed refrigerant is enabled to be taken from the compressor (11a) into the second four-way valve (13a), a second low pressure port through which the refrigerant is enabled to be taken from the second four-way valve (13a) into the compressor (11a), a high or low pressure gas pipe port through which the refrigerant is enabled to flow between the high or low pressure gas pipe (34) and the compressor (11a), and a second dead port fluidly connected to the second high pressure port when the refrigerant flows from the high or low pressure gas pipe port to the second low pressure port and fluidly connected to the second low pressure port when the refrigerant flows from the second high pressure port to the high or low pressure gas pipe port,

a first capillary tube (61a) allowing a fluidal flow between the second dead port and the refrigerant between the heat exchanger port and the outdoor heat exchanger (14a), and

a second capillary tube (62a) allowing a fluidal flow between the first dead port and the high or low pressure gas pipe (34).

2. The air conditioner according to claim 1, wherein during a cooling operation of the air conditioner, the refrigerant flows from the second dead port to the outdoor heat exchanger (14a) through the first capillary tube (61a), and the refrigerant flows from the high or low pressure gas pipe (34) through the first capillary (62a) and the first dead port to be taken into the compressor (11a).

3. The air conditioner according to claim 1 or 2, wherein during a heating operation of the air conditioner, the refrigerant flows from the first dead port through the second capillary tube (62a) into the high or low pressure gas pipe (34), and the refrigerant flows from the outdoor heat exchanger (14a) through the second dead port and the first capillary (61a) to be taken into the compressor (11a).

4. An air conditioner comprising: an indoor (40a, 40b, 40c) including an indoor heat exchanger (41a, 41b, 41c), an outdoor (10a) including an outdoor heat exchanger (14a) and a compressor (11a) for compressing a refrigerant, a liquid pipe (30) through which the refrigerant liquefied by one of the outdoor heat exchanger (14a) and the indoor heat exchanger (41a, 41b, 41c) is enabled to flow from the one of the outdoor heat exchanger (14a) and the indoor heat exchanger (41a, 41b, 41c) to the other one of the outdoor heat exchanger (14a) and the indoor heat exchanger (41a, 41b, 41c), and a high or low pressure gas pipe (34) through which the refrigerant is enabled to flow between the compressor (11a) and the indoor heat exchanger (41a, 41b, 41c) while being prevented from passing through the outdoor heat exchanger (14a),
wherein the outdoor (10a) further includes:

a first four-way valve (16a) including a first high pressure port through which the compressed refrigerant is enabled to be taken from the compressor (11a) into the first four-way valve (16a), a first low pressure port through which the refrigerant is enabled to be taken from the first four-way valve (16a) into the compressor (11a), a heat exchanger port through which the refrigerant is enabled to flow between the outdoor heat exchanger (14a) and the compressor (11a), and a first dead port fluidly connected to the first high pressure port when the refrigerant flows from the heat exchanger port to the first low pressure port and fluidly connected to the first low pressure port when the refrigerant flows from the first high pressure port to the heat exchanger port,

a second four-way valve (13a) including a second high pressure port through which the compressed refrigerant is enabled to be taken from the compressor (11a) into the second four-way valve (13a), a second low pressure port through which the refrigerant is enabled to be taken from the second four-way valve (13a) into the compressor (11a), a high or low pressure gas pipe port through which the refrigerant is enabled to flow between the high or low pressure gas pipe (34) and the compressor (11a), and a second dead port fluidly connected to the second high pressure port when the refrigerant flows from the high or low pressure gas pipe port to the second low pressure port and fluidly connected to the second low pressure port when the refrigerant flows from the second high pressure port to the high or low pressure gas pipe port,

a first bypass valve (63a) allowing a fluidal flow between the second dead port and the refrigerant between the heat exchanger port and the outdoor heat exchanger (14a), and

a second bypass valve (64a) allowing a fluidal flow between the first dead port and the high or low pressure gas pipe (34).

5. The air conditioner according to claim 4, wherein the first bypass valve is a check valve (63a) allowing the refrigerant to flow from the second dead port to the outdoor heat exchanger (14a), and the second bypass valve is a check valve (64a) allowing the refrigerant to flow from the first dead port to the high or low pressure gas pipe (34).

6. The air conditioner according to claim 4 or 5, wherein during a cooling operation of the air conditioner, the refrigerant flows from the second dead port to the outdoor heat exchanger (14a) through the first bypass valve (63a, 65a).

7. The air conditioner according to any one of claims 4-6, wherein during a heating operation of the air conditioner, the refrigerant flows from the first dead port to the high or low pressure gas pipe (34) through the second bypass valve (64a, 66a).

8. The air conditioner according to claim 4, wherein at least one of the first bypass valve (65a) and the second bypass valve (66a) is opened when the compressed refrigerant is supplied from the compressor (11a) to at least one of the first and second dead ports corresponding to the at least one of the first bypass valve (65a) and the second bypass valve (66a), and both of the first bypass valve (65a) and the second bypass valve (66a) are closed when the first and second dead ports fluidly communicate with the first and second low pressure ports respectively.

Drawing