JP2009299910A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioner capable of improving cooling operation performance and preventing leakage of refrigerant on an indoor unit side when renewing the refrigerant to such refrigerant having smaller specific volume of gas sucked by a compressor. <P>SOLUTION: This air conditioner is provided with an indoor unit 40 for renewal having an indoor heat exchanger 41 and an indoor expansion valve 42, an outdoor unit 10 for renewal having the compressor 11, an outdoor heat exchanger 14, and an outdoor expansion valve 15, and a liquid connection pipe and a gas connection pipe for connecting the indoor unit to the outdoor unit. The existing liquid connection pipe 30 used in the air conditioner before renewal is reused as the liquid connection pipe, and the existing gas connection pipe 34 is reused as the gas connection pipe. One or a plurality of new gas connection pipes 37 are additionally installed in parallel in a partial section or the whole section of the existing gas connection pipe to divide flow of the gas refrigerant and let respective flow of it flow into the existing gas connection pipe and the new gas connection pipe. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an air conditioner that uses a refrigerant having a large gas specific volume, and more particularly to refrigerant leakage blocking in a simultaneous heating and cooling multi-type air conditioner that uses a combustible refrigerant.

  Currently, the refrigerant of air conditioners is mainly CFC-based refrigerant R410A. As a feature of R410A, first, there is a small gas specific volume at the compressor suction point compared to R22 and R407C used before. If the gas specific volume is small, the compressor suction volume flow rate can be reduced when a mass flow rate equivalent to that of the refrigerant having a large gas specific volume is ensured. Considering a gas connection pipe that connects an indoor unit and an outdoor unit, the gas specific volume is small, so that the refrigerant flow rate in the pipe is reduced, the pressure loss in the gas connection pipe is reduced, and the performance can be improved. Especially in the cooling operation, since the gas pipe pressure is low and the specific volume increases even with the same refrigerant, the performance improvement effect is high. Thanks to the refrigerant physical properties of R410A, when renewing an existing air conditioner using R22 or R407C, the performance is not degraded even if the existing connection pipe is reused. Second, it is known as a non-flammable refrigerant without toxicity, and there is no concern that the refrigerant will burn even if the refrigerant leaks from the indoor unit side. Even if the refrigerant leaks, it is known to stop the refrigerant leak to the indoor unit by using a refrigerant leak detection device and a closing valve. For example, it is described in JP-A-1-225849.

  In the multi-type air conditioner, the number of simultaneous cooling and heating models is increasing due to the point that the cooling and heating operation can be switched individually for each indoor unit and the point that exhaust heat can be recovered. As an example of simultaneous cooling and heating models, there are models that require three connection pipes, a liquid pipe, a high-pressure gas pipe, and a low-pressure gas pipe. Connect the high-pressure gas pipe and the low-pressure gas pipe to the indoor unit gas pipe side. It is known to install a switching unit for switching and switch between heating operation and cooling operation. Furthermore, an example is also known in which a high-pressure gas pipe is used as a low-pressure gas flow path during a cooling only operation. In this case, it may be called high-low pressure piping.

Japanese Patent Laid-Open No. 1-225849

  However, since R410A has a high global warming potential (GWP) with respect to Patent Document 1, a refrigerant with a large gas specific volume, a slightly flammable refrigerant, or a flammable refrigerant has been studied as an alternative refrigerant. When renewing to an air conditioner using a refrigerant with a large gas specific volume and reusing the existing connection pipe, an increase in pressure loss in the gas connection pipe during cooling operation is inevitable, and the performance deteriorates.

  Next, in an air conditioner using a slightly flammable or flammable refrigerant, if the refrigerant leaks indoors, there is a risk of fire if the amount of leakage is large. However, it is necessary to install a closed valve as a new part on the air conditioner indoor unit side.

  The objective of this invention is obtaining the air conditioner which improves a performance even if it replaces with the air conditioner which uses a refrigerant | coolant with a large gas specific volume. Another object of the present invention is to obtain an air conditioner that uses existing products to block refrigerant leakage when refrigerant leakage occurs on the indoor unit side of an air conditioner that uses a combustible refrigerant.

  To achieve the above object, the present invention provides an update indoor unit having an indoor heat exchanger and an indoor expansion valve, an update outdoor unit having a compressor, an outdoor heat exchanger, and an outdoor expansion valve, A liquid connection pipe and a gas connection pipe connecting the indoor unit and the outdoor unit, and the existing liquid connection pipe used in the air conditioner before renewal is reused as the liquid connection pipe. In the air conditioner that reuses as the gas connection pipe, one or more new gas connection pipes are installed in parallel in a part or all of the existing gas connection pipe, and a gas refrigerant is installed in the existing gas connection pipe. The gas flow is divided into a gas connection pipe and the new gas connection pipe.

  Another feature of the present invention includes an indoor unit for update having an indoor heat exchanger and an indoor expansion valve, a compressor, an outdoor heat exchanger, and an outdoor expansion valve, which are connected to the compressor discharge side and the suction side. An outdoor unit for renewal having a high-low pressure pipe that can be switched between, a low-pressure pipe connected to the compressor suction side, a high-low pressure gas connection pipe and a low-pressure gas drawn from the outdoor unit to the gas pipe of the indoor unit A cooling / heating switching unit that connects a connection pipe, a liquid connection piping that connects the indoor unit and the outdoor unit, an indoor gas connection piping that connects the indoor unit and the cooling / heating switching unit, and a cooling / heating switching unit and a height of the outdoor unit. In a cooling / heating simultaneous multi-type air conditioner comprising a high / low pressure gas connection pipe connecting low pressure pipes and a low pressure gas connection pipe connecting the cooling / heating switching unit and the low pressure piping of the outdoor unit, it is used for an air conditioner before renewal. Existing liquid The secondary pipe is reused as the liquid connection pipe, the existing gas connection pipe is reused as either the high / low pressure gas connection pipe or the low pressure gas connection pipe, and the undeveloped high / low pressure gas connection pipe or the undeveloped low pressure gas connection It is to construct a new pipe.

  The air conditioner includes a refrigerant leakage detection mechanism, and includes an opening / closing mechanism on the indoor unit gas pipe side, and when refrigerant leakage is detected, closes the indoor expansion valve and the opening / closing mechanism of the corresponding indoor unit, It may be one that prevents all refrigerant leakage.

  The air conditioner includes a refrigerant leakage detection mechanism, and when the connection pipe on the indoor unit gas pipe side is divided into an existing gas branch pipe and a new gas branch pipe, the existing gas branch pipe and the new gas branch pipe are respectively provided. An open / close mechanism is provided, and when a refrigerant leak is detected, the indoor expansion valve of the corresponding indoor unit, the open / close mechanism of the existing gas branch pipe, and the open / close mechanism of the new gas branch pipe are closed to prevent all refrigerant leaks. Good.

  The cooling / heating simultaneous multi-type air conditioner may close the indoor expansion valve and the opening / closing mechanism in the order in which the refrigerant in the indoor unit flows in accordance with the operation state of the indoor unit when the refrigerant leaks.

  The air conditioner may be different in refrigerant used before and after the renewal, and the renewed refrigerant may have a larger specific volume of the compressor suction gas in an operation state in which the same capacity is ensured.

  Another feature of the present invention includes at least one indoor unit having an indoor heat exchanger and an indoor expansion valve, a compressor, an outdoor heat exchanger, and an outdoor expansion valve. At least one outdoor unit having a high / low pressure pipe that can be switched to the side of the compressor and a low pressure pipe connected to the compressor suction side, and a high / low pressure gas connection that is drawn from the outdoor unit to the gas pipe of the indoor unit A cooling / heating switching unit that connects a pipe and a low-pressure gas connection pipe, a liquid connection piping that connects the indoor unit and the outdoor unit, an indoor side gas connection pipe that connects the indoor unit and the cooling / heating switching unit, and the cooling / heating switching unit. A high and low pressure gas connection pipe connecting the high and low pressure pipes of the outdoor unit, and a low pressure gas connection pipe connecting the cooling / heating switching unit and the low pressure pipe of the outdoor unit. In a cooling / heating simultaneous multi-type air conditioner having an opening / closing mechanism on the pipe side and having a refrigerant leakage detection mechanism, when refrigerant leakage is detected, the indoor expansion valve of the corresponding indoor unit and the opening / closing mechanism of the cooling / heating switching unit The purpose is to prevent all refrigerant leakage.

  In the cooling and heating simultaneous multi-type air conditioner, the indoor unit and the outdoor unit are for renewal, and the existing liquid connection pipe used in the air conditioner before renewal is reused for the liquid connection pipe, and the existing gas connection The pipe may be reused as either a high-low pressure gas connection pipe or a low-pressure gas connection pipe, and a non-constructed high-low pressure gas connection pipe or a non-constructed low-pressure gas connection pipe may be newly constructed.

  In the cooling / heating simultaneous multi-type air conditioner, when refrigerant leaks, a part of the refrigerant in the indoor unit may be collected in the outdoor unit via the low-pressure gas pipe according to the operation state of the indoor unit.

  In the cooling / heating simultaneous multi-type air conditioner, the refrigerant to be used may be slightly flammable, flammable or toxic.

  According to the present invention, the performance can be improved even by renewing an air conditioner using a refrigerant having a large gas specific volume. Moreover, when a refrigerant leak occurs on the indoor unit side of an air conditioner that uses a flammable refrigerant, the refrigerant leak can be blocked.

  Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 1 shows an example of a refrigeration cycle, which includes one outdoor unit 10a and three indoor units 40a, 40b, and 40c. Here, the number of outdoor unit connections may be greater than one, and the number of indoor unit connections may be greater than or less than three.

  Here, the existing liquid connection pipe 30, the existing gas connection pipe 34, and the existing indoor gas branch pipes 35a, 35b, and 35c have connection pipe diameters that match the refrigerant physical properties of the air conditioner before the update. On the other hand, since the refrigerant of the newly introduced air conditioner 10a has a large gas specific volume, only the existing gas connection pipe 34 and the existing indoor gas branch pipes 35a, 35b, and 35c increase the pressure loss and lower the performance during the cooling operation. In order to prevent this, the new gas connection pipe 37 and the new indoor gas branch pipes 38a, 38b, and 38c are installed in parallel with the existing gas connection pipe 34 and the existing indoor gas branch pipes 35a, 35b, and 35c, and the gas-side flow path is cut off. Increase area and improve performance. Here, each of the new gas connection pipe 37 and the new indoor gas branch pipes 38a, 38b, 38c may be one, or a plurality of pipes may be used by using thin pipes. Further, the connecting portion between the existing gas connection pipe 34 and the new gas connection pipe 37 may be a teeth, or a Y-type branch pipe may be used. Similarly, the connecting portions of the existing indoor gas branch pipes 35a, 35b, and 35c and the new indoor gas branch pipes 38a, 38b, and 38c may be T-type branch pipes or Y-type branch pipes. The physical properties of the liquid refrigerant are usually not significantly different from the properties of the liquid refrigerant of the air conditioner before the update, but when the specific volume is increased, it may be newly added in the same manner as the gas pipe. In the construction procedure, the air conditioner 10a and the indoor units 40a, 40b, and 40c may be installed by finishing the construction of the new gas connection pipe 37 and the new indoor gas branch pipes 38a, 38b, and 38c first.

  Next, the refrigerant circulation during the cooling operation of the outdoor unit 10a and the indoor units 40a, 40b, and 40c will be described. For the outdoor unit 10a, the compressor 11a and the outdoor fan 19a are operated to fully open the outdoor expansion valve 15a, and the four-way valve 13a is on the cooling operation side. Here, the cooling operation side of the four-way valve 13a indicates a direction in which the compressor discharge side is connected to the outdoor heat exchanger 14a. Conversely, the heating operation side of the four-way valve 13a indicates a direction in which the compressor discharge side is connected to the four-way valve blocking valve side pipe 22a. Hereinafter, this expression will be used. The high-pressure gas refrigerant compressed by the compressor 11a is sent to the outdoor heat exchanger 14a by the four-way valve 13a, exchanges heat with the outdoor air and condenses to become a high-pressure liquid refrigerant, the outdoor expansion valve 15a, the liquid blocking valve 31a, and the existing It passes through the liquid connection pipe 30 and is sent to each of the indoor units 40a, 40b, and 40c. The sent liquid refrigerant is throttled by the indoor expansion valves 42a, 42b, and 42c, exchanges heat with room air, and evaporates to become a low-pressure gas refrigerant. A part of the low-pressure gas refrigerant discharged from each indoor unit passes through the existing indoor gas branch pipes 35a, 35b, and 35c, is sent to the gas blocking valve 32a through the existing gas connection pipe 34, and the rest is a new indoor gas. The branch pipes 38a, 38b, and 38c are joined together, joined through the new gas connection pipe 37, joined to the existing gas connection pipe 34 before the gas prevention valve 32, and sent to the gas prevention valve 32a. Alternatively, the new gas connection pipe 37 may be connected to the gas blocking valve 32 and the existing gas connection pipe 34 may be joined to the new gas connection pipe 37. The sent low-pressure gas refrigerant passes through the four-way valve blocking valve side pipe 22a, the four-way valve 13a, the four-way valve suction side pipe 23a, and the accumulator 20a and is circulated again to the compressor 11a. Here, the accumulator 20a may or may not be present.

  Next, the refrigerant circulation during the heating operation of the outdoor unit 10a and the indoor units 40a, 40b, and 40c will be described. Regarding the outdoor unit 10a, the compressor 11a is operated, the outdoor expansion valve 15a is opened, the outdoor fan 19a is operated, and the four-way valve 13a is on the heating operation side. The high-pressure gas refrigerant compressed by the compressor 11a is sent to the four-way valve blocking valve side pipe 22a and the gas blocking valve 32a by the four-way valve 13a. Part of the high-pressure gas refrigerant sent passes through the existing gas connection pipe 34 to the existing indoor gas branch pipes 35a, 35b, and 35c and is sent to the indoor units 40a, 40b, and 40c, respectively, and the rest is a new gas connection pipe 37. And are branched to the new indoor gas branch pipes 38a, 38b, and 38c, joined to the existing indoor gas branch pipes 35a, 35b, and 35c before the indoor unit, and sent to the indoor units 40a, 40b, and 40c, respectively. The sent high-pressure gas refrigerant exchanges heat with room air and condenses to become high-pressure liquid refrigerant, and is sent to the outdoor expansion valve 15a through the indoor expansion valves 42a, 42b, 42c, the existing liquid connection pipe 30, and the liquid blocking valve 31a. The liquid refrigerant sent is throttled by the outdoor expansion valve 15a, exchanges heat with outdoor air in the outdoor heat exchanger 14a, evaporates and becomes low-pressure gas refrigerant, and passes through the four-way valve 13a, the four-way valve suction side pipe 23a, and the accumulator 20a. It is sent to the compressor 11a and circulates again. On the heating operation side, the refrigerant in the gas connection pipe has a high pressure and a small specific volume, so the influence of pressure loss is small, and the performance improvement effect by the new connection pipe is small.

  FIG. 2 shows an example of the refrigeration cycle. In FIG. 2, no new indoor gas branch pipes 38 a, 38 b, 38 c are provided, and only the new gas connection pipe 37 is constructed in parallel with the existing gas connection pipe 34. If the construction of a new indoor gas branch pipe is equivalent to the ceiling of the building and takes a lot of time and cost, or if the length of the indoor gas branch pipe is short and the effect on performance is small, only the section of the existing gas connection pipe 34 It is possible to suppress the performance degradation due to the pressure loss. In addition, when the existing gas connection pipe 34 partially enters the back of the ceiling and construction is difficult, the new gas connection pipe 37 may be installed in parallel only in a section where the construction is possible. Similarly, when the work behind the ceiling is possible in a part of the section, the new indoor gas branch pipes 38a, 38b, and 38c are arranged in parallel only in the section that can be constructed in parallel with the existing indoor gas branch pipes 35a, 35b, and 35c. You may construct.

  FIG. 3 is an example of a refrigeration cycle, and is an example in which an outdoor unit 10b is added to FIG. The number of outdoor units connected may be more than two. When the outdoor unit 10a is in the cooling operation, the four-way valves 13a and 13b are on the cooling operation side. When the outdoor unit 10a is in the heating operation, both the four-way valves 13a and 13b are on the heating operation side. The four-way valves 13a and 13b are switched so as to be on the same operation side. The same applies when the outdoor unit is stopped. By aligning the directions of the four-way valves, the refrigerant flow is the same when both the outdoor unit 10a and the outdoor unit 10b are in operation. For example, when both the outdoor units 10a and 10b are in the cooling operation, the flow of the low-pressure gas refrigerant is partly sent to the outdoor unit 10a through the existing outdoor gas branch pipe 33a through the existing gas connection pipe 34. The rest passes through the existing outdoor gas branch pipe 33b and is sent to the outdoor unit 10b. A part that passes through the new gas connection pipe 37 is sent to the outdoor unit 10a through the new outdoor gas branch pipe 36a, and the rest is sent to the outdoor unit 10b through the new outdoor gas branch pipe 36b. Here, similarly to FIG. 2, when it is difficult to construct a part of the new pipe, only the sections that can be constructed may be constructed in parallel. In FIG. 3, the existing outdoor gas branch pipe 33 and the new outdoor gas branch pipe 36 are connected to two gas blocking valves 32 for each outdoor unit, and the respective gas blocking valves 32 are merged inside the outdoor unit. . Thereby, the piping construction man-hour at a site can be reduced and work can be simplified. However, since the number of gas blocking valves increases in the outdoor unit, it may be connected by piping outside the outdoor unit as shown in FIGS.

  FIG. 4 shows an example of the refrigeration cycle, and is an example in which the outdoor unit 10a can be operated simultaneously with cooling and heating, and a cooling / heating switching unit is installed in each gas pipe of the indoor unit. The simultaneous cooling and heating multi is composed of a total of three liquid pipes, low pressure gas pipes, and high and low pressure gas pipes, and is characterized in that the high and low pressure gas pipes are used as low pressure gas flow paths during the cooling operation. Further, the outdoor unit has a mechanism for switching between high and low pressures of the high and low pressure gas pipe, for example, a four-way valve, a three-way valve, a solenoid valve, and the like. Although FIG. 4 shows an example using a four-way valve, a three-way valve or an electromagnetic valve may be used.

  Here, the existing liquid connection pipe 30, the existing gas connection pipe 34, and the existing indoor gas branch pipes 35a, 35b, and 35c have connection pipe diameters that match the refrigerant physical properties of the air conditioner before the update, and are newly introduced air conditioners. Since the refrigerant of 10a has a large gas specific volume, the pressure loss increases and performance deteriorates only with the existing gas connection pipe 34 during cooling operation. However, as a feature of the simultaneous cooling and heating multi-machine, the high and low pressure gas pipes are also used as the low pressure gas flow path during the entire cooling. That is, the new gas connection pipe 37 is constructed between the low pressure gas blocking valve 39a and the low pressure side opening / closing mechanisms 52a, 52b, 52c of the cooling / heating switching units 50a, 50b, 50c, and during the cooling, the low pressure side opening / closing mechanisms 52a, 52b, By opening 52c, the new gas connection pipe 37 can also be used as a low pressure gas flow path. Thereby, the flow-path cross-sectional area of a gas pipe can be increased and cooling performance can be improved. In FIG. 4, the existing gas connection pipe 34 is connected to the high / low pressure gas blocking valve 32a and the new gas connection pipe 37 is connected to the low pressure gas blocking valve 39a. 34 may be connected to the low pressure gas blocking valve 39a, and the new gas connection pipe 37 may be connected to the high and low pressure gas blocking valve 32a. In this case, it is necessary to be careful not to make a mistake in connecting the high / low pressure gas pipe and the low pressure gas pipe to the cooling / heating switching units 50a, 50b, 50c. As in the previous examples, the number of new gas connection pipes 37 may be one, or a plurality of thin gas pipes may be used.

  Next, refrigerant circulation in which the outdoor unit 10a is in the cooling operation and the indoor units 40a, 40b, and 40c are in the cooling operation will be described. For the outdoor unit 10a, the compressor 11a and the outdoor fan 19a are operated, the outdoor expansion valves 15a and 18a are fully opened, the four-way valves 13a and 16a are on the cooling operation side, and the high-pressure side opening and closing of the cooling / heating switching units 50a, 50b, and 50c. The mechanisms 51a, 51b, 51c and the low-pressure side opening / closing mechanisms 52a, 52b, 52c are all open. The high-pressure gas refrigerant compressed by the compressor 11a is sent to the outdoor heat exchangers 14a and 17a by the four-way valves 13a and 16a, respectively, exchanges heat with the outdoor air, condenses into high-pressure liquid refrigerant, and the outdoor expansion valves 15a and 18a. Then, the fluid flows through the liquid blocking valve 31a and the existing liquid connection pipe 30 and is sent to the indoor units 40a, 40b, and 40c. The sent liquid refrigerant is throttled by the indoor expansion valves 42a, 42b, and 42c, exchanges heat with room air and evaporates to become a low-pressure gas refrigerant. The low-pressure gas refrigerant discharged from each indoor unit is sent to the cooling / heating switching units 50a, 50b, 50c. Here, a part of each refrigerant passes through the high-pressure side opening / closing mechanisms 51a, 51b, 51c, is sent to the high / low pressure gas blocking valve 32a through the existing gas connection piping 34, and the four-way valve blocking valve side piping 22a, the four-way valve 13a. The four-way valve suction side pipe 23a and the accumulator 20a are sent to the compressor 11a and circulate again. The remainder of the refrigerant sent to the cooling / heating switching units 50a, 50b, 50c passes through the low pressure side opening / closing mechanisms 52a, 52b, 52c, and passes through the new gas connection pipe 37, the low pressure gas blocking valve 39a, and the accumulator 20a to the compressor 11a. Is circulated again.

  Next, refrigerant circulation when the outdoor unit 10a is in cooling operation or heating operation and the indoor units 40a, 40b, and 40c are mixed in cooling operation and heating operation will be described. For the outdoor unit 10a, the four-way valve 13a switches to the heating operation and supplies the high-pressure gas refrigerant to the existing gas connection pipe 34. Further, the new gas connection pipe 37 is directly connected to the compressor suction side and pulled to a low pressure. Here, the pipe for supplying the high-pressure gas refrigerant to the indoor unit is only the existing gas connection pipe 34, and the pipe for supplying the low-pressure gas pipe is only the new gas connection pipe 37. However, the specific volume of the high-pressure gas refrigerant is small due to the physical properties of the refrigerant and is not easily affected by pressure loss, and there is no problem in performance even with the existing gas connection pipe 34 alone. On the other hand, since the low-pressure gas can select a pipe diameter considering the physical properties of the refrigerant to be renewed, there is no problem even with the new gas connection pipe 37. Also, the cooling load when the cooling operation or heating operation of the indoor unit is mixed is small, the cooling capacity is often not required up to the rated capacity, and the cooling capacity in the cooling / heating mixed period can be provided even with the pipe diameter of the existing gas connection pipe 34 Alternatively, the existing gas connection pipe 34 may be connected to the low-pressure gas blocking valve 39a, and the new gas connection pipe 37 may be connected to the high-low pressure gas blocking valve 32a.

  The four-way valve 16a is switched to a cooling operation or a heating operation according to the indoor cooling / heating load. Thereby, the refrigerant circulation direction in the outdoor unit and the liquid connection pipe changes, but the influence does not change in the refrigerant circulation direction of the high-low pressure gas pipe and the low-pressure gas pipe. In the cooling / heating switching unit, the operations of the high-pressure side opening / closing mechanism and the low-pressure side opening / closing mechanism vary depending on whether the room is in a heating operation, a cooling operation, or a stop. For example, when the indoor unit 40a performs a heating operation, the high-pressure side opening / closing mechanism 51a is opened and the low-pressure side opening / closing mechanism 52a is closed. By this solenoid valve operation, the high-pressure gas refrigerant sent to the existing gas connection pipe 34 is sent to the indoor unit 40a without leaking to the new gas connection pipe 37, and heating operation is possible. When the indoor unit 40b performs a cooling operation, the high-pressure side opening / closing mechanism 51b is closed and the low-pressure side opening / closing mechanism 52b is opened. By operating this solenoid valve and opening the indoor expansion valve 42b, the liquid refrigerant is depressurized and evaporated, and exchanges heat with room air to become a low-pressure gas refrigerant. Then, the low-pressure gas refrigerant is sent to the new gas connection pipe 37 through the low-pressure side opening / closing mechanism 52b. When the indoor unit 40c stops, the high-pressure side opening / closing mechanism 51c is closed and the indoor expansion valve 42c is closed so that the refrigerant does not flow to the indoor unit. The low-pressure side opening / closing mechanism 52c may be closed or open.

  FIG. 5 shows an example of the refrigeration cycle, in which the high-pressure side opening / closing mechanisms 51a, 51b, 51c of the cooling / heating switching units 50a, 50b, 50c are removed from FIG. It is not necessary to operate the indoor units individually at the same time, and in the case of only cooling or heating only, it is suitable for reducing the cost. In the case of all cooling, by opening the low-pressure side opening / closing mechanisms 52a, 52b, 52c, a part of the low-pressure gas refrigerant that has passed through the indoor unit is sent to the outdoor unit through the new gas connection pipe 37, and the rest is the existing gas It passes through the connecting pipe 34 and is sent to the outdoor unit. Thereby, the flow-path cross-sectional area of gas piping can be increased, and cooling performance can be improved. In the case of all heating, by closing the low pressure side opening / closing mechanisms 52a, 52b, 52c, the new gas connection pipe 37 is closed, and the high pressure gas refrigerant discharged from the outdoor unit passes through the existing gas connection pipe 34 to the indoor unit. Sent. The outdoor unit can recognize the cooling / heating switching units 50a, 50b, and 50c by installing the simultaneous cooling and heating multi, and can switch the low-pressure side opening / closing mechanisms 52a, 52b, and 52c by cooling and heating. When a standard machine as shown in FIG. 1 is installed, it is not preferable because it must be made at the time of product development so that the cooling / heating switching unit can be recognized, and the cost and time of product development are required.

  FIG. 6 is an example of a refrigeration cycle, and is an example in which an outdoor unit 10b is added to FIG. The number of outdoor units connected may be more than two. When the outdoor unit is in the cooling only operation, both the four-way valves 13a and 13b are on the cooling operation side. Further, when the outdoor unit is in the cooling / heating simultaneous operation and the heating only operation, both the four-way valves 13a and 13b are on the heating operation side. The four-way valves 13a and 13b are switched so as to be on the same operation side. The same applies when the outdoor unit is stopped. For example, when both the outdoor units 10a and 10b are in the cooling operation, the flow of the low-pressure gas refrigerant is partly sent to the outdoor unit 10a through the existing outdoor gas branch pipe 33a through the existing gas connection pipe 34. The rest passes through the existing outdoor gas branch pipe 33b and is sent to the outdoor unit 10b. A part that passes through the new gas connection pipe 37 is sent to the outdoor unit 10a through the new outdoor gas branch pipe 36a, and the rest is sent to the outdoor unit 10b through the new outdoor gas branch pipe 36b. In this way, even when there are a plurality of outdoor units with simultaneous cooling and heating, the performance during the cooling operation is improved. Further, when the outdoor unit is in the cooling / heating simultaneous operation and the full heating operation, the high-pressure gas refrigerant from the outdoor unit is sent from each of the new outdoor gas branch pipes 36 a and 36 b and sent to the indoor unit through the new gas connection pipe 37. A part of the low-pressure gas refrigerant returning from the indoor unit to the outdoor unit passes through the existing gas connection pipe 34 and is sent to the outdoor unit 10a through the existing outdoor gas branch pipe 33a, and the rest passes through the existing outdoor gas branch pipe 33b. 10b. The pipe for supplying the high-pressure gas refrigerant to the indoor unit is only the existing gas connection pipe 34, and the pipe for supplying the low-pressure gas pipe is only the new gas connection pipe 37. However, the specific volume of the high-pressure gas is small due to the physical properties of the refrigerant and is not easily affected by pressure loss, and there is no problem in performance even with the existing gas connection pipe 34 alone. On the other hand, since the low-pressure gas can select a pipe diameter considering the physical properties of the refrigerant to be renewed, there is no problem even with the new gas connection pipe 37. Further, the heat exchange side pipes of the four-way valves 13a and 13b of the simultaneous cooling and heating outdoor unit are connected to the four-way valve suction side pipes 23a and 23b via the capillary tubes, and are formed as pseudo three-way valves. As a result, the outdoor heat exchangers 14a and 14b are not divided and are switched to high and low pressure by the four-way valves 16a and 16b. By not dividing the outdoor heat exchanger, it is not necessary to divide the gas header of the outdoor heat exchanger, and it is possible to consolidate the liquid side distributor and the outdoor expansion valve into one, thereby reducing the manufacturing cost.

  FIG. 7 shows an example of the refrigeration cycle. In FIG. 7, cooling / heating switching units 50a, 50b, and 50c are installed, and refrigerant leakage detectors 62a, 62b, and 62c are installed in the living rooms 61a, 61b, and 61c, respectively. By installing the switching unit on the gas pipe side, it is possible to prevent all circulating refrigerant from leaking into the room where the indoor unit is installed, and to prevent diseases due to fire, suffocation, and toxicity.

  In addition, like the cooling / heating switching units 50a and 50b, the opening / closing mechanisms 51a and 51b may be respectively installed so as to close the flows of the existing indoor gas branch pipes 35a and 35b and the new indoor gas branch pipes 38a and 38b. The open / close mechanism 51c may be installed so as to close the indoor gas branch pipe as in the cooling / heating switching unit 50c.

  An example of the case where refrigerant leakage is not detected is shown in the room 61a. Each of the opening / closing mechanisms 51a is opened, and the indoor expansion valve is opened / closed depending on the operating state. Next, an example in the case where refrigerant leakage is detected is shown by living rooms 61b and 61c. When the refrigerant leakage is detected, the indoor expansion valve 42b and the opening / closing mechanism 51b of the indoor unit 40b are all closed. Similarly, the indoor expansion valve 42c and the opening / closing mechanism 51c of the indoor unit 40c are all closed. In order to make the opening / closing mechanism fully closed, a bidirectional solenoid valve may be used. Further, an expansion valve may be used when the refrigerant leakage amount of the opening / closing mechanism is small.

  When the living room is a large space and includes all of the indoor units 40a, 40b, 40c, for example, the indoor expansion valves 42a, 42b, 42c and the opening / closing mechanisms 51a, 51b, 51c of the indoor units 40a, 40b, 40c are all closed. .

  Furthermore, the refrigerant leakage detection may be predicted from the refrigeration cycle operation state. If the refrigeration cycle falls short during operation and the cause is not considered other than refrigerant leakage, the indoor expansion valves of all the indoor units and the open / close valves of the cooling / heating switching unit may be closed, and the outdoor unit may be shut down.

  FIG. 8 is an example of a control flow when refrigerant leaks from the indoor unit. Although the opening / closing mechanism is described as an electromagnetic valve, it may be an expansion valve.

  When the refrigerant detector in the living room is activated, it is first determined whether the outdoor unit is in operation or the indoor unit is in operation. Here, when the outdoor unit is stopped or the indoor unit is stopped, the indoor expansion valve and the electromagnetic valve are all controlled to be closed.

  Next, it is determined whether the indoor unit is in a cooling operation or a heating operation. In the cooling operation, the refrigerant flows from the indoor expansion valve to the electromagnetic valve via the indoor heat exchanger. Therefore, the indoor expansion valve is closed and the liquid refrigerant remaining in the indoor heat exchanger or the indoor gas branch pipe is collected in the gas pipe or the outdoor unit via the electromagnetic valve, and then the electromagnetic valve is closed. The cooling-time refrigerant recovery time TsetC to be recovered needs to be determined in advance so that it can be recovered. Care must be taken because the refrigerant leaks from the solenoid valve if it remains open after the liquid refrigerant is collected. For this reason, TsetC may change depending on the degree of refrigerant leakage, liquid pressure, and gas pressure. In the heating operation, the refrigerant flows from the electromagnetic valve to the indoor expansion valve through the indoor heat exchanger. For this reason, the solenoid valve is closed and the indoor expansion valve is kept open until the liquid refrigerant condensed in the indoor heat exchanger is collected in the liquid pipe, and the indoor expansion valve is closed before the refrigerant leaks from the liquid pipe. It is necessary to determine the heating refrigerant recovery time TsetH for recovery so that it can be recovered in advance. Here, the time may vary depending on the degree of refrigerant leakage, the high-pressure gas pressure and the low-pressure gas pressure, and the degree of indoor heat exchange subcooling immediately before the leakage.

  Next, when the indoor unit is not in the cooling operation or the heating operation, the indoor expansion valve and the electromagnetic valve are all controlled to be closed.

  FIG. 9 shows operations of the indoor expansion valve 42a, the high-pressure side opening / closing mechanism 51a, and the low-pressure side opening / closing mechanism 52a when refrigerant leaks from the indoor unit 40a. Here, the refrigerant leak detector 62a is installed in the living room 61a in which the indoor unit 40a is installed. Thereby, it is possible to prevent all the circulating refrigerant from leaking into the living room 61a where the indoor unit 40a is installed, and to prevent diseases due to fire, suffocation, and toxicity. The cooling / heating switching unit 50a is often installed outside the living room 61a, but may be installed in the living room.

  When the refrigerant leaks from the indoor unit 40a, the living room 61a is filled with the refrigerant, and the refrigerant leak detector 62a detects the refrigerant leak. In conjunction with this detection, the indoor expansion valve 42a, the high-pressure side opening / closing mechanism 51a, and the low-pressure side opening / closing mechanism 52a of the indoor unit 40a are all closed. Here, in order to fully close the high pressure side opening / closing mechanism and the low pressure side opening / closing mechanism, a bidirectional solenoid valve may be used. Further, an expansion valve may be used when the refrigerant leakage amount of the opening / closing mechanism is small.

  Further, when the living room is a large space and includes indoor units 40b and 40c, for example, the indoor expansion valves 42b and 42c, the high-pressure side opening / closing mechanisms 51b and 51c, and the low-pressure side opening / closing mechanisms 52b and 52c of the indoor units 40b and 40c are all closed. And

  Furthermore, the refrigerant leakage detection may be predicted from the refrigeration cycle operation state. If the refrigeration cycle falls short during operation and the cause is not considered other than refrigerant leakage, the indoor expansion valves of all the indoor units and the open / close valves of the cooling / heating switching unit may be closed, and the outdoor unit may be shut down.

  FIG. 10 is an example of a control flow when the refrigerant leaks from the indoor unit. The high-pressure side opening / closing mechanism and the low-pressure side opening / closing mechanism are described as electromagnetic valves, but may be expansion valves.

  When the refrigerant detector in the living room is activated, it is first determined whether the outdoor unit is in operation or the indoor unit is in operation. Here, when the outdoor unit is stopped or the indoor unit is stopped, it is considered that the indoor expansion valve, the high pressure solenoid valve, and the low pressure solenoid valve are basically closed. However, when the outdoor unit is in operation and the indoor unit is stopped, the low-pressure solenoid valve may be open, or the valve may be open due to an unexpected situation. Therefore, the indoor expansion valve, high pressure solenoid valve, and low pressure solenoid valve are all controlled to be closed.

  Next, it is determined whether the indoor unit is in a cooling operation or a heating operation. In the cooling operation, the indoor expansion valve is open, the high-pressure solenoid valve is closed, and the low-pressure solenoid valve is open. Therefore, after closing the indoor expansion valve and recovering the liquid refrigerant remaining in the indoor heat exchanger or the indoor gas branch pipe to the outdoor unit side via the low pressure solenoid valve, the low pressure solenoid valve is closed. The cooling-time refrigerant recovery time TsetC to be recovered needs to be determined in advance so that it can be recovered. Care must be taken because the refrigerant leaks from the low-pressure solenoid valve if it remains open after the liquid refrigerant is recovered. For this reason, TsetC may change depending on the degree of refrigerant leakage, liquid pressure, and low-pressure gas pressure. In the heating operation, the indoor expansion valve is open, the high-pressure solenoid valve is open, and the low-pressure solenoid valve is closed. Therefore, after closing the indoor expansion valve and the high-pressure solenoid valve and opening the low-pressure solenoid valve, the liquid refrigerant remaining in the indoor heat exchanger or the indoor gas branch pipe is recovered to the outdoor unit side via the low-pressure solenoid valve, and then the low-pressure solenoid valve is recovered. Close the valve. It is necessary to determine the heating refrigerant recovery time TsetH for recovery so that it can be recovered in advance. Care must be taken because the refrigerant leaks from the low-pressure solenoid valve if it remains open after recovery of the liquid refrigerant. The time may vary depending on the degree of refrigerant leakage, the high-pressure gas pressure and the low-pressure gas pressure, and the degree of indoor heat exchange subcooling immediately before the leakage.

  Next, when the indoor unit is not in the cooling operation or the heating operation, the indoor expansion valve, the high pressure solenoid valve, and the low pressure solenoid valve are all controlled to be closed.

The refrigeration cycle system diagram which shows Example 1 of this invention. The refrigeration cycle system | strain diagram which shows Example 2 of this invention. The refrigeration cycle system diagram which shows Example 3 of this invention. The refrigeration cycle system diagram which shows Example 4 of this invention. The refrigerating-cycle system | strain diagram which shows Example 5 of this invention. The refrigeration cycle system diagram which shows Example 6 of this invention. The refrigeration cycle system diagram which shows Example 7 of this invention. The flowchart which shows the control flow of an indoor expansion valve and the gas side opening / closing mechanism at the time of a refrigerant | coolant leak. The refrigeration cycle system diagram which shows Example 8 of this invention. The flowchart which shows the control flow of an indoor expansion valve at the time of a refrigerant | coolant leak, a high voltage | pressure side opening / closing mechanism, and a low voltage | pressure side opening / closing mechanism.

Explanation of symbols

10a, 10b Outdoor unit 11a, 11b Compressor 12a, 12b Compressor discharge side check valve 13a, 13b, 16a, 16b Four-way valve 14a, 14b, 17a, 17b Outdoor heat exchanger 15a, 15b, 18a, 18b Outdoor expansion valve 19a, 19b Outdoor fans 20a, 20b Accumulators 22a, 22b Four-way valve blocking valve side piping 23a, 23b Four-way valve suction side piping 30 Existing liquid connection piping 31a, 31b Liquid blocking valves 32a, 32b (High / low pressure) Gas blocking valves 33a, 33b Existing outdoor (low pressure) gas branch pipe 34 Existing gas connection pipe 35a, 35b, 35c Existing indoor gas branch pipe 36a, 36b New outdoor (high / low pressure) gas branch pipe 37 New gas connection pipe 38a, 38b, 38c New indoor gas branch pipe 39a, 39b Low pressure gas blocking valves 40a, 40b, 40c indoor units 41a, 41b, 1c Indoor heat exchangers 42a, 42b, 42c Indoor expansion valves 50a, 50b, 50c Cooling / heating switching units 51a, 51b, 51c (high pressure side) opening / closing mechanisms 52a, 52b, 52c Low pressure side opening / closing mechanisms 61a, 61b, 61c Living rooms 62a, 62b 62c Refrigerant leak detector

Claims (10)

A renewal indoor unit having an indoor heat exchanger and an indoor expansion valve, a renewing outdoor unit having a compressor, an outdoor heat exchanger, and an outdoor expansion valve, and a liquid connecting the indoor unit and the outdoor unit An air conditioner that has connection piping and gas connection piping, and reuses the existing liquid connection piping and existing gas connection piping that were used in the air conditioner before the update, as the updated liquid connection piping and gas connection piping, respectively. In
An air conditioner characterized in that a new gas connection pipe is additionally installed in parallel with the existing gas connection pipe, and a gas refrigerant is separately supplied to the existing gas connection pipe and the new additional gas connection pipe. High and low pressure that has an indoor unit for renewal having an indoor heat exchanger and an indoor expansion valve, a compressor, an outdoor heat exchanger, and an outdoor expansion valve that can be switched between the discharge side and the suction side of the compressor A renewal outdoor unit having a pipe and a low-pressure pipe connected to the compressor suction side; A switching unit, a liquid connection pipe connecting the indoor unit and the outdoor unit, an indoor side gas connection pipe connecting the indoor unit and the cooling / heating switching unit, and a high level connecting the cooling / heating switching unit and the high / low pressure piping of the outdoor unit. In the simultaneous cooling and heating multi-type air conditioner including a low-pressure gas connection pipe, and a low-pressure gas connection pipe connecting the cooling / heating switching unit and the low-pressure pipe of the outdoor unit,
The existing liquid connection pipe used in the air conditioner before update is reused as the liquid connection pipe, and the existing gas connection pipe is reused as either the high-low pressure gas connection pipe or the low-pressure gas connection pipe. A cooling / heating simultaneous multi-type air conditioner characterized in that a high-low pressure gas connection pipe or a low-pressure gas connection pipe that is not reused is additionally provided.   The refrigerant leakage detection mechanism according to claim 1, further comprising an opening / closing mechanism on the indoor unit gas piping side, and when refrigerant leakage is detected, the indoor expansion valve and the opening / closing mechanism of the corresponding indoor unit are closed to An air conditioner characterized by preventing refrigerant from leaking.   2. The refrigerant leakage detection mechanism according to claim 1, wherein when the connection pipe on the indoor unit gas pipe side is divided into an existing gas branch pipe and a new gas branch pipe, an opening / closing mechanism is provided for each of the existing gas branch pipe and the new gas branch pipe. When the refrigerant leakage is detected, the indoor expansion valve of the corresponding indoor unit, the open / close mechanism of the existing gas branch pipe, and the open / close mechanism of the new gas branch pipe are closed to prevent leakage of all the refrigerant. An air conditioner characterized by   5. The air conditioner according to claim 3, wherein when refrigerant leakage is detected, the indoor expansion valve and the opening / closing mechanism are closed in the order in which the refrigerant in the indoor unit flows in accordance with the operating state of the indoor unit. .   In any one of Claims 1-5, the refrigerant | coolant used before and behind an update differs, Comprising: In the driving | running state which ensures the same capability, the refrigerant | coolant used after an update is the specific volume of compressor suction gas. An air conditioner characterized by the fact that it becomes larger. It has at least one indoor unit having an indoor heat exchanger and an indoor expansion valve, a compressor, an outdoor heat exchanger, and an outdoor expansion valve, and the connection to the discharge side or suction side of the compressor can be switched. At least one outdoor unit having a high and low pressure pipe, a low pressure pipe connected to the compressor suction side, and a high and low pressure gas connection pipe and a low pressure gas connection pipe drawn from the outdoor unit to the gas pipe of the indoor unit At least one cooling / heating switching unit connected, a liquid connection pipe connecting the indoor unit and the outdoor unit, an indoor gas connection pipe connecting the indoor unit and the cooling / heating switching unit, the cooling / heating switching unit and the outdoor unit A high / low pressure gas connection pipe connecting the high / low pressure pipe and a low pressure gas connection pipe connecting the cooling / heating switching unit and the low pressure pipe of the outdoor unit. Has a closing mechanism on the pipe side, the simultaneous cooling and heating multi-type air conditioner having a refrigerant leakage detection mechanism,
An air conditioner that prevents leakage of all refrigerants by closing an indoor expansion valve and an opening / closing mechanism of a cooling / heating switching unit of an indoor unit in which leakage is detected when refrigerant leakage is detected.   In Claim 7, the indoor unit and the outdoor unit are for renewal, the existing liquid connection pipe used in the air conditioner before renewal is reused as the liquid connection pipe, and the existing gas connection pipe is used as the high and low pressure gas connection pipe. Alternatively, the air conditioner is reused as one of the low-pressure gas connection pipes, and additionally provided on the high-low pressure gas connection pipe or the low-pressure gas connection pipe on the non-reuse side.   9. The air conditioner according to claim 7, wherein a part of the refrigerant in the indoor unit is collected in the outdoor unit through the low-pressure gas pipe according to the operation state of the indoor unit when the refrigerant leaks.   The air conditioner according to any one of claims 7 to 9, wherein the refrigerant used is a refrigerant having slight flammability, flammability, or toxicity.

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