WO2014128970A1

WO2014128970A1 - Air conditioner

Info

Publication number: WO2014128970A1
Application number: PCT/JP2013/054788
Authority: WO
Inventors: 祐治本村; 嶋本　大祐; 孝好本多; 森本　修; 浩二西岡; 小野　達生
Original assignee: 三菱電機株式会社
Priority date: 2013-02-25
Filing date: 2013-02-25
Publication date: 2014-08-28
Also published as: EP2960602A1; JP6095764B2; CN105074359A; JPWO2014128970A1; EP2960602B1; EP2960602A4; US20150369498A1

Abstract

An air conditioner (100) executes either a heat recovery defrost operation mode in which the retained heat capacity of a heating medium is utilized, or a bypass defrost operation mode in which the retained heat capacity of the heating medium is not utilized, when frost adheres to a heat source-side heat exchanger during a heating operation mode.

Description

Air conditioner

The present invention relates to an air conditioner applied to, for example, a building multi air conditioner.

Conventionally, in an air conditioner such as a building multi-air conditioner, a refrigerant is circulated between, for example, an outdoor unit that is a heat source device arranged outside a building and an indoor unit arranged inside a building. And the refrigerant | coolant thermally radiated and absorbed heat, and air-conditioning object space was cooled or heated with the air heated and cooled. As a refrigerant used in such an air conditioner, for example, an HFC (hydrofluorocarbon) refrigerant is often used. In addition, one using a natural refrigerant such as carbon dioxide (CO ₂ ) has been proposed.

Also, in an air conditioner called a chiller, heat or heat is generated by a heat source device arranged outside the building. Then, water, antifreeze, etc. are heated and cooled by a heat exchanger arranged in the heat source machine, and this is transferred to a fan coil unit, a panel heater, etc., which are indoor units, for cooling or heating (for example, Patent Documents) 1).

Also, a waste heat recovery type chiller, which is connected to four water pipes between the heat source unit and the indoor unit, supplies cooled and heated water at the same time, and can freely select cooling or heating in the indoor unit (For example, refer to Patent Document 2).

Also, there is a configuration in which a heat exchanger for the primary refrigerant and the secondary refrigerant is disposed in the vicinity of each indoor unit and the secondary refrigerant is conveyed to the indoor unit (for example, see Patent Document 3).

Also, there is a configuration in which an outdoor unit and a branch unit having a heat exchanger are connected by two pipes and a secondary refrigerant is conveyed to the indoor unit (for example, see Patent Document 4).

Further, in an air conditioner such as a multi air conditioner for buildings, a refrigerant such as water is circulated from the outdoor unit to the repeater and a heat medium such as water is circulated from the repeater to the indoor unit. Some are configured to circulate (see, for example, Patent Document 5).

Japanese Patent Laying-Open No. 2005-140444 (page 4, FIG. 1, etc.) JP-A-5-280818 (4th, 5th page, FIG. 1 etc.) Japanese Patent Laid-Open No. 2001-289465 (pages 5 to 8, FIG. 1, FIG. 2, etc.) JP 2003-343936 A (Page 5, FIG. 1) WO 2010/050002 (pages 11 to 15, FIG. 8 etc.)

In conventional air conditioners such as multi air conditioners for buildings, since the refrigerant is circulated to the indoor unit, the refrigerant may leak into the room. On the other hand, in the air conditioning apparatus as described in Patent Document 1 and Patent Document 2, the refrigerant does not pass through the indoor unit. However, in the air conditioning apparatus as described in Patent Document 1 and Patent Document 2, it is necessary to heat or cool the heat medium in the heat source unit outside the building and transport it to the indoor unit side. For this reason, the circulation path of a heat medium becomes long. Here, if it is going to convey the heat which carries out the work of predetermined heating or cooling with a heat medium, the amount of energy consumption by conveyance power etc. will become higher than a refrigerant. Therefore, when the circulation path becomes long, the conveyance power becomes very large. From this, it can be seen that energy saving can be achieved in the air conditioner if the circulation of the heat medium can be well controlled.

In the air conditioner as described in Patent Document 2, in order to be able to select cooling or heating for each indoor unit, four pipes must be connected from the outdoor side to the indoor side. It was bad. In the air conditioner described in Patent Document 3, since it is necessary to have a secondary medium circulation means such as a pump for each indoor unit, it is not only an expensive system but also a large noise, which is practical. It was not something. In addition, since the heat exchanger is in the vicinity of the indoor unit, the possibility that the refrigerant leaks in a place close to the room could not be excluded.

In the air conditioner as described in Patent Document 4, since the primary refrigerant after heat exchange flows into the same flow path as the primary refrigerant before heat exchange, a plurality of indoor units are connected. In addition, the maximum capacity of each indoor unit could not be demonstrated, resulting in a wasteful configuration. In addition, since the branch unit and the extension pipe are connected by a total of four pipes of two cooling units and two heating units, as a result, the system in which the outdoor unit and the branch unit are connected by four pipes. The system was similar in construction to that of poor workability.

Also, in conventional air conditioners such as multi air conditioners for buildings, frost forms on the surface of the outdoor heat exchanger due to heat exchange with the outside air in the outdoor unit during the heating operation. Therefore, it is necessary to implement defrosting operation mode regularly. However, while the defrosting operation is being performed, the high-temperature and high-pressure refrigerant required for the indoor unit to perform the heating operation cannot be conveyed to the indoor unit, and according to the required indoor heating load. Heating operation could not be performed.

In addition, even if the air conditioner has the function of taking outside air and transporting it to the indoor side for the purpose of ventilation, the blower is stopped during the defrosting operation in order to prevent cold air from entering the room due to outside air taking in. To do. By doing so, the heating operation according to the requested indoor heating load cannot be executed.

In an air conditioner as described in Patent Document 5, a reduction in room temperature can be suppressed by circulating a secondary heat medium through an indoor unit during a defrosting operation. However, the continuation of the heating operation of the indoor unit including ventilation by taking in outside air has not been considered.

The present invention has been made to solve the above-described problems, and an object thereof is to provide an air conditioner having a plurality of defrosting operation modes and maintaining comfort.

An air conditioner according to the present invention includes a compressor, a heat source side heat exchanger, a plurality of expansion devices, a refrigerant side flow path of a plurality of heat exchangers between heat media, and a plurality of refrigerant flow switching devices that switch a refrigerant circulation path. A refrigerant circulation circuit that circulates the heat source side refrigerant by connecting with a refrigerant pipe, a plurality of heat medium transfer devices provided corresponding to each of the plurality of heat exchangers between heat media, and a plurality of use side heat exchangers A heat medium circulation circuit that circulates the heat medium by connecting the heat medium side flow paths of the plurality of heat medium heat exchangers with a heat medium transport pipe, and bypasses at least the heat medium heat exchanger And an air conditioner that includes a bypass pipe installed so that the heat source side refrigerant can be returned to the compressor, and in which the heat source side refrigerant and the heat medium exchange heat in the heat exchanger between heat mediums. The refrigerant flow switching device to the heating side In other words, the heat medium is heated by at least one of the heat exchangers between the heat mediums, and at least one of the heat medium transfer devices is operated and heated to at least one of the use side heat exchangers. In the heating operation mode for supplying the heat medium, and during the heating operation mode, the refrigerant flow switching device is switched to a cooling side to operate at least one of the heat medium transport devices, and the heat exchange between the heat media A heat recovery defrosting operation mode in which the heat source side refrigerant absorbs heat of the heat medium in at least one of the heaters and melts frost formed around the heat source side heat exchanger; and during the heating operation mode, Bypass defrosting operation mode in which frost formed around the heat source side heat exchanger is melted by switching the refrigerant flow switching device to the cooling side and flowing a part or all of the heat source side refrigerant to the bypass pipe. And It is intended to.

Since the air conditioning apparatus according to the present invention has the “heat recovery defrosting operation mode” and the “bypass defrosting operation mode” as the defrosting operation mode, one of the defrosting operation modes is executed. It is possible to maintain comfort.

It is the schematic which shows the example of installation of the air conditioning apparatus which concerns on embodiment of this invention. It is a schematic circuit block diagram which shows an example of the circuit structure of the air conditioning apparatus which concerns on embodiment of this invention. It is a refrigerant circuit diagram which shows the flow of the refrigerant | coolant at the time of the cooling only operation mode of the air conditioning apparatus which concerns on embodiment of this invention. It is a refrigerant circuit diagram which shows the flow of the refrigerant | coolant at the time of the heating only operation mode of the air conditioning apparatus which concerns on embodiment of this invention. It is a refrigerant circuit diagram which shows the flow of the refrigerant | coolant at the time of the air conditioning apparatus which concerns on embodiment of this invention in the air conditioning heating mixed operation mode. It is a refrigerant circuit diagram which shows the flow of the refrigerant | coolant in the "1st heat recovery defrost operation mode (1)" of the air conditioning apparatus which concerns on embodiment of this invention, and the flow of a heat carrier. It is a refrigerant circuit diagram which shows the flow of the refrigerant | coolant in the "1st heat recovery defrost operation mode (2)" of the air conditioning apparatus which concerns on embodiment of this invention, and the flow of a heat carrier. It is a refrigerant circuit diagram which shows the flow of the refrigerant | coolant at the time of "2nd heat recovery defrost operation mode" of the air conditioning apparatus which concerns on embodiment of this invention, and the flow of a heat carrier. It is a refrigerant circuit diagram which shows the flow of the refrigerant | coolant in the "1st bypass defrosting operation mode" of the air conditioning apparatus which concerns on embodiment of this invention, and the flow of a heat carrier. It is a graph which shows an example of the relationship between the air volume of the fan for every difference of the temperature which can reduce a heat medium, and the heat medium temperature holding | maintenance time when heating operation is continued with the air volume. It is a refrigerant circuit diagram which shows the flow of the refrigerant | coolant in the "2nd bypass defrosting operation mode" of the air conditioning apparatus which concerns on embodiment of this invention, and the flow of a heat carrier.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram illustrating an installation example of an air conditioner according to an embodiment of the present invention. Based on FIG. 1, the installation example of an air conditioning apparatus is demonstrated. This air conditioner uses a refrigeration cycle (refrigerant circulation circuit A, heat medium circulation circuit B) that circulates refrigerant (heat source side refrigerant, heat medium) so that each indoor unit can be in the cooling mode or the heating mode as an operation mode. You can choose freely. FIG. 1 schematically shows an entire air conditioner connecting a plurality of indoor units 3. In addition, in the following drawings including FIG. 1, the relationship of the size of each component may be different from the actual one.

In FIG. 1, the air-conditioning apparatus according to the present embodiment includes an outdoor unit (heat source unit) 1, a plurality of indoor units 3, and one relay interposed between the outdoor unit 1 and the indoor unit 3. And a unit 2. The relay unit 2 performs heat exchange between the heat source side refrigerant and the heat medium. The outdoor unit 1 and the relay unit 2 are connected by a refrigerant pipe 4 that conducts the heat source side refrigerant. The relay unit 2 and the indoor unit 3 are connected by a pipe (heat medium transport pipe) 5 that conducts the heat medium. The cold or warm heat generated by the outdoor unit 1 is delivered to the indoor unit 3 via the relay unit 2.

The outdoor unit 1 is usually disposed in an outdoor space 6 that is a space (for example, a rooftop) outside a building 9 such as a building, and supplies cold or hot energy to the indoor unit 3 via the relay unit 2. . The indoor unit 3 is disposed at a position where cooling air or heating air can be supplied to the indoor space 7 that is a space (for example, a living room) inside the building 9, and the cooling air is supplied to the indoor space 7 that is the air-conditioning target space. Alternatively, heating air is supplied. The relay unit 2 is configured as a separate housing from the outdoor unit 1 and the indoor unit 3 so as to be installed at a position different from the outdoor space 6 and the indoor space 7. The refrigerant pipe 4 and the pipe 5 are respectively connected to transmit cold heat or hot heat supplied from the outdoor unit 1 to the indoor unit 3.

The operation of the air conditioner according to the embodiment of the present invention will be briefly described.
The heat source side refrigerant is conveyed from the outdoor unit 1 to the relay unit 2 through the refrigerant pipe 4. The transported heat source side refrigerant exchanges heat with the heat medium in the heat exchanger related to heat medium in the relay unit 2 (heat exchanger 25 described later), and heats or cools the heat medium. That is, hot water or cold water is produced by the heat exchanger between heat media. The hot water or cold water produced by the relay unit 2 is transported to the indoor unit 3 through the pipe 5 by a heat medium transport device (a pump 31 described later), and the indoor unit 3 performs heating operation (warm water). The operation state may be as long as it is necessary) or a cooling operation (as long as the operation state requires cold water).

Examples of the heat source side refrigerant include single refrigerants such as R-22, R-134a, and R-32, pseudo-azeotropic mixed refrigerants such as R-410A and R-404A, and non-azeotropic mixed refrigerants such as R-407C. A refrigerant or mixture thereof containing a double bond in the chemical formula and having a relatively low global warming coefficient such as CF ₃ CF═CH ₂ , or a natural refrigerant such as CO ₂ or propane can be used.

On the other hand, as the heat medium, for example, water, antifreeze, a mixture of water and antifreeze, a mixture of water and an additive having a high anticorrosive effect, or the like can be used.

As shown in FIG. 1, in the air conditioner according to the present embodiment, the outdoor unit 1 and the relay unit 2 use two refrigerant pipes 4, and the relay unit 2 and each indoor unit 3 have two. These pipes 5 are connected to each other. Thus, in the air conditioning apparatus according to the present embodiment, by connecting each unit (outdoor unit 1, indoor unit 3, and relay unit 2) using two pipes (refrigerant pipe 4, pipe 5). Construction is easy.

In FIG. 1, the relay unit 2 is installed in a space such as the back of the ceiling (hereinafter simply referred to as a space 8) that is inside the building 9 but is different from the indoor space 7. An example is shown. Therefore, the relay unit 2 may be installed anywhere as long as it is outside the ceiling or other than the living space and has some ventilation with the outside. It can also be installed in a space that is ventilated. Further, the relay unit 2 can be installed in the vicinity of the outdoor unit 1. However, it should be noted that if the distance from the relay unit 2 to the indoor unit 3 is too long, the transfer power of the heat medium becomes considerably large, so that the effect of energy saving is reduced.

FIG. 1 shows an example in which the outdoor unit 1 is installed in the outdoor space 6, but the present invention is not limited to this. For example, the outdoor unit 1 may be installed in an enclosed space such as a machine room with a ventilation opening. If the waste heat can be exhausted outside the building 9 by an exhaust duct, the outdoor unit 1 may be installed inside the building 9. It may be installed, or may be installed inside the building 9 when the water-cooled outdoor unit 1 is used. Even if the outdoor unit 1 is installed in such a place, no particular problem occurs.

In FIG. 1, the case where the indoor unit 3 is a ceiling cassette type is shown as an example. However, the present invention is not limited to this, and the indoor unit 3 is directly or directly connected to the indoor space 7 such as a ceiling embedded type or a ceiling suspended type. As long as the air for heating or the air for cooling can be blown out, any kind may be used.

Furthermore, the number of connected outdoor units 1, indoor units 3, and relay units 2 is not limited to the number shown in FIG. 1, but according to the building 9 in which the air conditioner according to the present embodiment is installed. What is necessary is just to determine the number.

When a plurality of relay units 2 are connected to one outdoor unit 1, the plurality of relay units 2 may be installed in a shared space in a building such as a building or in a space such as a ceiling. it can. By doing so, an air-conditioning load can be covered with the heat exchanger between heat media in each relay unit 2. In addition, the indoor unit 3 can be installed at a distance or height within the allowable transfer range of the heat medium transfer device in each relay unit 2, and can be arranged on the entire building such as a building. .

FIG. 2 is a schematic circuit configuration diagram showing an example of a circuit configuration of the air conditioning apparatus according to the present embodiment (hereinafter referred to as the air conditioning apparatus 100). Based on FIG. 2, the structure of the air conditioning apparatus 100, ie, the effect | action of each actuator which comprises the refrigerant circuit, is demonstrated in detail. As shown in FIG. 2, the outdoor unit 1 and the relay unit 2 include a heat exchanger related to heat medium (refrigerant-water heat exchanger) 25 a and a heat exchanger related to heat medium (refrigerant—) provided in the relay unit 2. The refrigerant pipe 4 is connected via a water heat exchanger 25b. Moreover, the relay unit 2 and the indoor unit 3 are connected by the piping 5 through the heat exchanger related to heat medium 25a and the heat exchanger related to heat medium 25b.

[Outdoor unit 1]
In the outdoor unit 1, a compressor 10, a first refrigerant flow switching device 11 such as a four-way valve, a heat source side heat exchanger 12, and an accumulator 19 are connected and connected in series through a refrigerant pipe 4. Yes. The outdoor unit 1 is also provided with a refrigerant connection pipe 4a, a refrigerant connection pipe 4b, a check valve 13a, a check valve 13b, a check valve 13c, and a check valve 13d. Regardless of the operation required by the indoor unit 3, relay connection pipe 4a, refrigerant connection pipe 4b, check valve 13a, check valve 13b, check valve 13c, and check valve 13d are provided. The flow of the heat source side refrigerant flowing into the unit 2 can be in a certain direction.

The compressor 10 sucks the heat source side refrigerant, compresses the heat source side refrigerant, and transfers it to the refrigerant circulation circuit A in a high temperature / high pressure state. Good. The first refrigerant flow switching device 11 has a flow of the heat source side refrigerant in the heating operation mode (in the heating only operation mode and the heating main operation mode) and in the cooling operation mode (in the all cooling operation mode and the cooling main operation mode). ) To switch the flow of the heat source side refrigerant.

The heat source side heat exchanger 12 functions as an evaporator during heating operation, functions as a condenser (or radiator) during cooling operation, and fluid such as air supplied from a blower such as a fan (not shown) and the heat source side Heat exchange is performed with the refrigerant, and the heat source side refrigerant is vaporized or condensed and liquefied. The accumulator 19 is provided on the suction side of the compressor 10 and stores excess refrigerant due to a difference between the heating operation and the cooling operation, or excess refrigerant with respect to a transient change in operation.

The check valve 13c is provided in the refrigerant pipe 4 between the relay unit 2 and the first refrigerant flow switching device 11, and the heat source side refrigerant is only in a predetermined direction (direction from the relay unit 2 to the outdoor unit 1). It allows flow. The check valve 13a is provided in the refrigerant pipe 4 between the heat source side heat exchanger 12 and the relay unit 2, and flows the heat source side refrigerant only in a predetermined direction (direction from the outdoor unit 1 to the relay unit 2). It is acceptable. The check valve 13d is provided in the refrigerant connection pipe 4a and causes the heat source side refrigerant discharged from the compressor 10 to flow through the relay unit 2 during the heating operation. The check valve 13b is provided in the refrigerant connection pipe 4b, and causes the heat source side refrigerant returned from the relay unit 2 during the heating operation to flow to the suction side of the compressor 10.

In the outdoor unit 1, the refrigerant connection pipe 4 a includes a refrigerant pipe 4 between the first refrigerant flow switching device 11 and the check valve 13 c, and a refrigerant pipe 4 between the check valve 13 a and the relay unit 2. Are connected to each other. In the outdoor unit 1, the refrigerant connection pipe 4b includes a refrigerant pipe 4 between the check valve 13c and the relay unit 2, a refrigerant pipe 4 between the heat source side heat exchanger 12 and the check valve 13a, Are connected. FIG. 2 shows an example in which the refrigerant connection pipe 4a, the refrigerant connection pipe 4b, the check valve 13a, the check valve 13b, the check valve 13c, and the check valve 13d are provided. However, the present invention is not limited to this, and these are not necessarily provided.

[Indoor unit 3]
Each indoor unit 3 is equipped with a use side heat exchanger 35. The use side heat exchanger 35 is connected to the heat medium flow control device 34 and the second heat medium flow switching device 33 of the relay unit 2 by the pipe 5. The use side heat exchanger 35 exchanges heat between air supplied from a blower such as a fan (not shown) and a heat medium, and supplies heating air or cooling air to be supplied to the indoor space 7. Is to generate

Further, in the indoor unit 3, a duct 43 and the like are attached to the use side heat exchanger 35. And it can also ventilate by taking in outside air via the duct 43 with respect to the indoor space 7 using the air blower which is not illustrated.

FIG. 2 shows an example in which four indoor units 3 are connected to the relay unit 2, which are illustrated as an indoor unit 3 a, an indoor unit 3 b, an indoor unit 3 c, and an indoor unit 3 d from the upper side of the drawing. Yes. In accordance with the indoor unit 3a to the indoor unit 3d, the use side heat exchanger 35 also has a use side heat exchanger 35a, a use side heat exchanger 35b, a use side heat exchanger 35c, and a use side heat exchanger from the upper side of the drawing. It is illustrated as 35d. As in FIG. 1, the number of indoor units 3 connected is not limited to the four shown in FIG. Further, FIG. 2 shows an example in which the duct 43 is connected to the indoor unit 3a. However, the indoor unit 3 to which the duct 43 can be connected is not limited to one, and the indoor unit 3b to the indoor unit can be connected. It may be connected to any of 3d.

[Relay unit 2]
The relay unit 2 includes at least two or more heat exchangers for heat medium 25, two expansion devices 26, two opening / closing devices (opening / closing device 27, opening / closing device 29), and two second refrigerant flow switching. Device 28, two heat medium transfer devices (hereinafter referred to as pump 31), four first heat medium flow switching devices 32, four second heat medium flow switching devices 33, and four heat media A flow rate adjusting device 34 is mounted.

The two heat exchangers for heat medium 25 (heat exchanger for heat medium 25a, heat exchanger for heat medium 25b) are provided with a condenser (when the heat is supplied to the indoor unit 3 in the heating operation). When supplying cold heat to the indoor unit 3 that is in the cooling operation as a radiator, it functions as an evaporator, performs heat exchange between the heat-source-side refrigerant and the heat medium, and is generated by the outdoor unit 1 The cold heat or warm heat stored in the side refrigerant is transmitted to the heat medium. The heat exchanger related to heat medium 25a is provided between the expansion device 26a and the second refrigerant flow switching device 28a in the refrigerant circuit A, and serves to cool the heat medium in the cooling / heating mixed operation mode. is there. Further, the heat exchanger related to heat medium 25b is provided between the expansion device 26b and the second refrigerant flow switching device 28b in the refrigerant circulation circuit A, and serves to heat the heat medium in the cooling / heating mixed operation mode. Is.

The two expansion devices 26 (the expansion device 26a and the expansion device 26b) have functions as pressure reducing valves and expansion valves, and expand the heat source side refrigerant by reducing the pressure. The expansion device 26a is provided on the upstream side of the heat exchanger related to heat medium 25a in the flow of the heat source side refrigerant during the cooling operation. The expansion device 26b is provided on the upstream side of the heat exchanger related to heat medium 25b in the flow of the heat source side refrigerant during the cooling operation. The two expansion devices 26 may be constituted by devices whose opening degree can be variably controlled, for example, electronic expansion valves.

The two opening / closing devices (opening / closing device 27, opening / closing device 29) are configured by electromagnetic valves or the like that can be opened and closed by energization, and open / close the refrigerant pipe 4. That is, the opening and closing of the two opening / closing devices is controlled according to the operation mode, and the flow path of the heat source side refrigerant is switched. The opening / closing device 27 is provided in the refrigerant pipe 4 on the inlet side of the heat-source-side refrigerant (the refrigerant pipe 4 located at the lowest level in the drawing among the refrigerant pipes 4 connecting the outdoor unit 1 and the relay unit 2). The opening / closing device 29 is provided in a pipe (bypass pipe 20) connecting the refrigerant pipe 4 on the inlet side of the heat source side refrigerant and the refrigerant pipe 4 on the outlet side. The opening / closing device 27 and the opening / closing device 29 may be any devices that can switch the refrigerant flow path. For example, an electronic expansion valve or the like that can variably control the opening degree may be used.

The two second refrigerant flow switching devices 28 (second refrigerant flow switching device 28a, second refrigerant flow switching device 28b) are constituted by, for example, a four-way valve or the like, and the heat exchanger related to heat medium according to the operation mode. The flow of the heat source side refrigerant is switched so that 25 acts as a condenser or an evaporator. The second refrigerant flow switching device 28a is provided on the downstream side of the heat exchanger related to heat medium 25a in the flow of the heat source side refrigerant during the cooling operation. The second refrigerant flow switching device 28b is provided on the downstream side of the heat exchanger related to heat medium 25b in the flow of the heat source side refrigerant in the cooling only operation mode.

The two pumps 31 (pump 31a and pump 31b) circulate the heat medium that conducts the pipe 5 to the heat medium circuit B. The pump 31 a is provided in the pipe 5 between the heat exchanger related to heat medium 25 a and the second heat medium flow switching device 33. The pump 31 b is provided in the pipe 5 between the heat exchanger related to heat medium 25 b and the second heat medium flow switching device 33. The two pumps 31 may be configured by, for example, capacity-controllable pumps, and the flow rate thereof may be adjusted according to the load in the indoor unit 3.

The four first heat medium flow switching devices 32 (the first heat medium flow switching device 32a to the first heat medium flow switching device 32d) are configured by three-way valves or the like, and heat the flow of the heat medium. Switching between the heat exchanger for medium 25a and the heat exchanger 25b for heat medium is performed. The number of first heat medium flow switching devices 32 is set according to the number of indoor units 3 installed (here, four). In the first heat medium flow switching device 32, one of the three sides is in the heat exchanger 25a, one of the three is in the heat exchanger 25b, and one of the three is in the heat medium flow rate. Each is connected to the adjustment device 34 and provided on the outlet side of the heat medium flow path of the use side heat exchanger 35. The first heat medium flow switching device 32a, the first heat medium flow switching device 32b, the first heat medium flow switching device 32c, and the first heat medium flow switching corresponding to the indoor unit 3 from the upper side of the drawing. Illustrated as device 32d. The switching of the heat medium flow path includes not only complete switching from one to the other but also partial switching from one to the other.

The four second heat medium flow switching devices 33 (second heat medium flow switching device 33a to second heat medium flow switching device 33d) are configured by three-way valves or the like, and heat the flow of the heat medium. Switching between the heat exchanger for medium 25a and the heat exchanger 25b for heat medium is performed. The second heat medium flow switching device 33 is provided in a number (four in this case) corresponding to the number of indoor units 3 installed. In the second heat medium flow switching device 33, one of the three heat transfer medium heat exchangers 25a, one of the three heat transfer medium heat exchangers 25b, and one of the three heat transfer side heats. Each is connected to the exchanger 35 and provided on the inlet side of the heat medium flow path of the use side heat exchanger 35. In correspondence with the indoor unit 3, the second heat medium flow switching device 33a, the second heat medium flow switching device 33b, the second heat medium flow switching device 33c, and the second heat medium flow switching are performed from the upper side of the drawing. Illustrated as device 33d. The switching of the heat medium flow path includes not only complete switching from one to the other but also partial switching from one to the other.

The four heat medium flow control devices 34 (the heat medium flow control device 34a to the heat medium flow control device 34d) are configured by two-way valves or the like that can control the opening area, and control the flow rate of the heat medium flowing through the pipe 5. To do. The number of the heat medium flow control devices 34 is set according to the number of indoor units 3 installed (four in this case). One of the heat medium flow control devices 34 is connected to the use side heat exchanger 35 and the other is connected to the first heat medium flow switching device 32, and is connected to the outlet side of the heat medium flow channel of the use side heat exchanger 35. Is provided. In other words, the heat medium flow control device 34 adjusts the amount of the heat medium flowing into the indoor unit 3 according to the temperature of the heat medium flowing into the indoor unit 3 and the temperature of the heat medium flowing out, so that the optimum heat according to the indoor load is adjusted. The medium amount can be provided to the indoor unit 3.

It should be noted that, corresponding to the indoor unit 3, the heat medium flow rate adjustment device 34a, the heat medium flow rate adjustment device 34b, the heat medium flow rate adjustment device 34c, and the heat medium flow rate adjustment device 34d are illustrated from the upper side of the drawing. Further, the heat medium flow control device 34 may be provided on the inlet side of the heat medium flow path of the use side heat exchanger 35. Further, the heat medium flow control device 34 may be provided on the inlet side of the heat medium flow path of the use side heat exchanger 35 and between the second heat medium flow switching device 33 and the use side heat exchanger 35. Good. Furthermore, when the indoor unit 3 does not require a load such as stop or thermo OFF, the heat medium supply to the indoor unit 3 can be stopped by fully closing the heat medium flow control device 34.

If the first heat medium flow switching device 32 or the second heat medium flow switching device 33 is added with the function of the heat medium flow control device 34, the heat medium flow control device 34 may be omitted. Is possible.

Further, the relay unit 2 is provided with a temperature sensor 40 (temperature sensor 40a, temperature sensor 40b) for detecting the temperature of the heat medium on the outlet side of the heat exchanger 25 between heat mediums. Information (temperature information) detected by the temperature sensor 40 is sent to a control device 50 that performs overall control of the operation of the air conditioner 100, and the driving frequency of the compressor 10, the rotation speed of the blower not shown, and the first refrigerant. It is used for control such as switching of the flow path switching device 11, driving frequency of the pump 31, switching of the second refrigerant flow path switching device 28, switching of the flow path of the heat medium, adjustment of the heat medium flow rate of the indoor unit 3. become. In addition, although the control device 50 is shown as an example in a state where it is mounted separately from each unit, the present invention is not limited to this. At least one of the outdoor unit 1, the indoor unit 3, and the relay unit 2, or Each unit may be mounted so as to be communicable.

Moreover, the control apparatus 50 is comprised by the microcomputer etc., Based on the detection information in various detection means, and the instruction | indication from a remote control, the drive frequency of the compressor 10, the rotation speed (including ON / OFF) of an air blower, Switching of the first refrigerant flow switching device 11, driving of the pump 31, opening of the throttle device 26, opening / closing of the opening / closing devices (opening / closing device 27, opening / closing device 29), switching of the second refrigerant flow switching device 28, first Each actuator (pump 31, first heat medium flow switching device 32, switching of the heat medium flow switching device 32, switching of the second heat medium flow switching device 33, driving of the heat medium flow control device 34, etc. The driving parts such as the second heat medium flow switching device 33, the expansion device 26, the second refrigerant flow switching device 28, etc.) are controlled, and each operation mode to be described later is executed.

The pipe 5 that conducts the heat medium is composed of one that is connected to the heat exchanger related to heat medium 25a and one that is connected to the heat exchanger related to heat medium 25b. The pipe 5 is branched (here, four branches each) according to the number of indoor units 3 connected to the relay unit 2. The pipe 5 is connected by a first heat medium flow switching device 32 and a second heat medium flow switching device 33. By controlling the first heat medium flow switching device 32 and the second heat medium flow switching device 33, the heat medium from the heat exchanger related to heat medium 25a flows into the use-side heat exchanger 35, or the heat medium Whether the heat medium from the intermediate heat exchanger 25b flows into the use side heat exchanger 35 is determined.

In the air conditioner 100, the compressor 10, the first refrigerant flow switching device 11, the heat source side heat exchanger 12, the switching device 27, the switching device 29, the second refrigerant flow switching device 28, and heat exchange between heat media. The refrigerant flow path, the expansion device 26 and the accumulator 19 of the container 25 are connected by the refrigerant pipe 4 to constitute the refrigerant circulation circuit A. Further, the heat medium flow path of the intermediate heat exchanger 25, the pump 31, the first heat medium flow switching device 32, the heat medium flow control device 34, the use side heat exchanger 35, and the second heat medium flow path. The switching device 33 is connected by the pipe 5 to constitute the heat medium circulation circuit B. That is, a plurality of use side heat exchangers 35 are connected in parallel to each of the heat exchangers 25 between heat mediums, and the heat medium circulation circuit B has a plurality of systems.

Therefore, in the air conditioner 100, the outdoor unit 1 and the relay unit 2 are connected via the heat exchanger related to heat medium 25a and the heat exchanger related to heat medium 25b provided in the relay unit 2, and the relay unit 2 is connected. And the indoor unit 3 are also connected via the heat exchanger related to heat medium 25a and the heat exchanger related to heat medium 25b. That is, in the air conditioner 100, the heat source side refrigerant circulating in the refrigerant circuit A and the heat medium circulating in the heat medium circuit B exchange heat in the intermediate heat exchanger 25a and the intermediate heat exchanger 25b. It is like that. By using such a configuration, the air conditioner 100 can realize an optimal cooling operation or heating operation according to the indoor load.

[Operation mode]
Each operation mode which the air conditioning apparatus 100 performs is demonstrated. The air conditioner 100 can perform a cooling operation or a heating operation in the indoor unit 3 based on an instruction from each indoor unit 3. That is, the air conditioning apparatus 100 can perform the same operation for all the indoor units 3 and can perform different operations for each of the indoor units 3.

The operation mode executed by the air conditioner 100 includes a heating only operation mode in which all the driven indoor units 3 execute the heating operation, and a cooling only operation in which all the driven indoor units 3 execute the cooling operation. There are a heating main operation mode in which the heating load is larger than the cooling load in the mode and the mixed cooling and heating operation mode, and a cooling main operation mode in which the cooling load is larger than the heating load in the cooling and heating mixed operation mode. In the heating only operation mode and the heating main operation mode, there is a defrosting operation mode in which frost attached to the heat source side heat exchanger 12 is removed as a result of heat exchange with the outside air in the heat source side heat exchanger 12. Below, each operation mode is demonstrated with the flow of the heat source side refrigerant | coolant and a heat medium.

[Cooling operation mode]
FIG. 3 is a refrigerant circuit diagram illustrating a refrigerant flow when the air-conditioning apparatus 100 is in the cooling only operation mode. In FIG. 3, the cooling only operation mode will be described by taking as an example a case where a cooling load is generated in all of the use side heat exchangers 35a to 35d. In addition, in FIG. 3, the piping represented by the thick line has shown the piping through which the heat source side refrigerant | coolant flows. In FIG. 3, the flow direction of the heat source side refrigerant is indicated by a solid line arrow, and the flow direction of the heat medium is indicated by a broken line arrow.

3, in the cooling only operation mode shown in FIG. 3, in the outdoor unit 1, the first refrigerant flow switching device 11 is switched so that the heat source side refrigerant discharged from the compressor 10 flows into the heat source side heat exchanger 12.

In the relay unit 2, the pump 31a and the pump 31b are driven, the heat medium flow control devices 34a to 34d are opened, and the heat medium heat exchanger 25a and the heat medium heat exchanger 25b are used respectively. The heat medium circulates between the side heat exchanger 35a and the use side heat exchanger 35d. The second refrigerant flow switching device 28a and the second refrigerant flow switching device 28b are switched to the cooling side, the opening / closing device 27 is open, and the opening / closing device 29 is closed.

First, the flow of the heat source side refrigerant in the refrigerant circuit A will be described.
The low-temperature and low-pressure refrigerant is compressed by the compressor 10 and discharged as a high-temperature and high-pressure gas refrigerant. The high-temperature and high-pressure gas refrigerant discharged from the compressor 10 passes through the heat source side heat exchanger 12 via the first refrigerant flow switching device 11, and is the air in the outdoor space 6 (hereinafter referred to as outside air). Heat exchange is performed to obtain a high-temperature / high-pressure liquid or a two-phase refrigerant, and after passing through the check valve 13a, the refrigerant connection pipe 4a is conducted and flows out of the outdoor unit 1. The high-temperature and high-pressure liquid or two-phase refrigerant that has flowed out of the outdoor unit 1 flows into the relay unit 2 through the refrigerant pipe 4.

The high-temperature / high-pressure liquid or two-phase refrigerant that has flowed into the relay unit 2 passes through the opening / closing device 27, and is branched and expanded by the expansion device 26a and the expansion device 26b to become a low-temperature / low-pressure two-phase refrigerant. . These two-phase refrigerant flows into the heat exchanger related to heat medium 25a and the heat exchanger related to heat medium 25b, evaporates while absorbing heat from the heat medium circulating in the heat medium circuit B, and becomes a low-temperature gas refrigerant. . The gas refrigerant flowing out from the heat exchanger related to heat medium 25a and the heat exchanger related to heat medium 25b flows out from the relay unit 2 through the second refrigerant flow switching device 28a and the second refrigerant flow switching device 28b, and the refrigerant The pipe 4 is conducted, passes through the check valve 13 c, and is sucked again into the compressor 10 through the first refrigerant flow switching device 11 and the accumulator 19.

At this time, the expansion device 26 calculates a value obtained by converting the pressure of the heat-source-side refrigerant flowing between the heat exchanger 25 between the heat medium 25 and the expansion device 26 into a saturation temperature and the temperature on the outlet side of the heat exchanger 25 between the heat media. The opening degree is controlled so that the superheat (superheat degree) obtained as the difference becomes constant. In addition, when the temperature of the intermediate position of the intermediate heat exchanger 25 can be measured, the saturation temperature obtained by converting the temperature at the intermediate position may be used instead. In this case, it is not necessary to install a pressure sensor, and the system can be configured at low cost.

Next, the flow of the heat medium in the heat medium circuit B will be described.
In the cooling only operation mode, the cold heat of the heat source side refrigerant is transmitted to the heat medium in both the

heat exchangers

25a and 25b, and the cooled heat medium is pressurized by the pump 31a and the pump 31b. It flows out and flows into the use side heat exchanger 35a to the use side heat exchanger 35d via the second heat medium flow switching device 33a to the second heat medium flow switching device 33d. The heat medium absorbs heat from the indoor air in the use side heat exchanger 35a to the use side heat exchanger 35d, thereby cooling the indoor space 7.

Then, the heat medium flows out from the use side heat exchanger 35a to the use side heat exchanger 35d and flows into the heat medium flow control device 34a to the heat medium flow control device 34d. At this time, the use side heat exchanger 35a is controlled by the operation of the heat medium flow control device 34a to the heat medium flow control device 34d so that the flow rate of the heat medium is controlled to a flow rate necessary to cover the air conditioning load required in the other room. It flows into the use side heat exchanger 35d. The heat medium flowing out from the heat medium flow control device 34a to the heat medium flow control device 34d passes through the first heat medium flow switching device 32a to the first heat medium flow switching device 32d, and then the heat exchanger related to heat medium 25a. And it flows in into the heat exchanger 25b between heat | fever media, passes the amount of heat | fever for the heat | fever absorbed from the indoor space 7 through the indoor unit 3 to the refrigerant | coolant side, and is sucked into the pump 31a and the pump 31b again.

In the pipe 5 of the use side heat exchanger 35, the heat medium is directed from the second heat medium flow switching device 33 to the first heat medium flow switching device 32 via the heat medium flow control device 34. Flowing. The air conditioning load required in the indoor space 7 is the temperature detected by the temperature sensor 40 or the temperature detected by the temperature sensor 40 and the temperature of the heat medium flowing out from the use side heat exchanger 35. This can be covered by controlling the difference to keep it at the target value. As the outlet temperature of the heat exchanger related to heat medium 25, either the temperature sensor 40a or the temperature sensor 40b may be used, or an average temperature of these may be used.

At this time, the first heat medium flow switching device 32 and the second heat medium flow switching device 33 seem to secure a flow path that flows to both the heat medium heat exchanger 25a and the heat medium heat exchanger 25b. In addition, the opening degree is controlled to an intermediate opening degree or an opening degree corresponding to the heat medium temperature at the outlet of the heat exchanger related to heat medium 25a and the heat exchanger related to heat medium 25b. In addition, the usage-side heat exchanger 35 should be controlled by the temperature difference between the inlet and the outlet, but the temperature of the heat medium on the inlet side of the usage-side heat exchanger 35 is the temperature detected by the temperature sensor 40. The number of temperature sensors can be reduced by using the temperature sensor 40, and the system can be configured at low cost.

When the cooling only operation mode is executed, it is not necessary to flow the heat medium to the use side heat exchanger 35 (including the thermo-off) having no heat load, so the flow path is closed by the heat medium flow control device 34 and the use side The heat medium is prevented from flowing to the heat exchanger 35. In FIG. 3, the heat medium flows because all of the use side heat exchangers 35a to 35d have a heat load. However, when the heat load disappears, the corresponding heat medium flow control device 34 is used. Should be fully closed. Then, when a heat load is generated again, the corresponding heat medium flow control device 34 is opened, and the heat medium is circulated. The same applies to other operation modes described below.

[Heating operation mode]
FIG. 4 is a refrigerant circuit diagram illustrating a refrigerant flow when the air-conditioning apparatus 100 is in the heating only operation mode. In FIG. 4, the heating only operation mode will be described by taking as an example a case where a heating load is generated in all of the use side heat exchanger 35a to the use side heat exchanger 35d. In addition, in FIG. 4, the piping represented by the thick line has shown the piping through which the heat source side refrigerant | coolant flows. In FIG. 4, the flow direction of the heat source side refrigerant is indicated by solid line arrows, and the flow direction of the heat medium is indicated by broken line arrows.

In the heating only operation mode shown in FIG. 4, in the outdoor unit 1, the first refrigerant flow switching device 11 is connected to the relay unit without passing the heat source side refrigerant discharged from the compressor 10 through the heat source side heat exchanger 12. Switch to 2 In the relay unit 2, the pump 31a and the pump 31b are driven, the heat medium flow control devices 34a to 34d are opened, and the heat medium heat exchanger 25a and the heat medium heat exchanger 25b are used respectively. The heat medium circulates between the side heat exchanger 35a and the use side heat exchanger 35d. The second refrigerant flow switching device 28a and the second refrigerant flow switching device 28b are switched to the heating side, the opening / closing device 27 is closed, and the opening / closing device 29 is open.

First, the flow of the heat source side refrigerant in the refrigerant circuit A will be described.
The low-temperature and low-pressure refrigerant is compressed by the compressor 10 and discharged as a high-temperature and high-pressure gas refrigerant. The high-temperature and high-pressure gas refrigerant discharged from the compressor 10 passes through the first refrigerant flow switching device 11, conducts through the refrigerant connection pipe 4 a, passes through the check valve 13 d, and flows out of the outdoor unit 1. The high-temperature and high-pressure gas refrigerant that has flowed out of the outdoor unit 1 flows into the relay unit 2 through the refrigerant pipe 4. The high-temperature and high-pressure gas refrigerant that has flowed into the relay unit 2 is branched and passes through the second refrigerant flow switching device 28a and the second refrigerant flow switching device 28b, and the heat exchanger related to heat medium 25a and heat between the heat media. It flows into each of the exchangers 25b.

The high-temperature and high-pressure gas refrigerant flowing into the heat exchanger related to heat medium 25a and the heat exchanger related to heat medium 25b is condensed and liquefied while dissipating heat to the heat medium circulating in the heat medium circuit B, and becomes a high-pressure liquid refrigerant. . The liquid refrigerant flowing out of the heat exchanger related to heat medium 25a and the heat exchanger related to heat medium 25b is expanded by the expansion device 26a and the expansion device 26b to become a low-temperature, low-pressure two-phase refrigerant. These two-phase refrigerants merge, flow out of the relay unit 2 through the opening / closing device 29, and flow into the outdoor unit 1 again through the refrigerant pipe 4. The refrigerant that has flowed into the outdoor unit 1 is conducted through the refrigerant connection pipe 4b, passes through the check valve 13b, and flows into the heat source side heat exchanger 12 that functions as an evaporator.

The heat source side refrigerant flowing into the heat source side heat exchanger 12 absorbs heat from the outside air in the heat source side heat exchanger 12 and becomes a low-temperature / low-pressure gas refrigerant. The low-temperature and low-pressure gas refrigerant flowing out from the heat source side heat exchanger 12 is again sucked into the compressor 10 via the first refrigerant flow switching device 11 and the accumulator 19.

At this time, the expansion device 26 has a value obtained by converting the pressure of the heat-source-side refrigerant flowing between the heat exchanger related to heat medium 25 and the expansion device 26 into a saturation temperature, and the temperature on the outlet side of the heat exchanger related to heat medium 25. The degree of opening is controlled so that the subcool (degree of supercooling) obtained as a difference from the above becomes constant. In addition, when the temperature of the intermediate position of the heat exchanger 25 between heat media can be measured, you may use it instead of the saturation temperature which converted the temperature in the intermediate position. In this case, it is not necessary to install a pressure sensor, and the system can be configured at low cost.

Next, the flow of the heat medium in the heat medium circuit B will be described.
In the heating only operation mode, the heat of the heat source side refrigerant is transmitted to the heat medium in both the heat exchanger related to heat medium 25a and the heat exchanger related to heat medium 25b, and the heated heat medium is piped 5 by the pump 31a and the pump 31b. The inside will be allowed to flow. The heat medium pressurized and discharged by the pump 31a and the pump 31b passes through the second heat medium flow switching device 33a to the second heat medium flow switching device 33d, and the use side heat exchanger 35a to the use side heat exchange. Flow into the vessel 35d. The indoor space 7 is heated by the heat medium radiating heat to the indoor air by the use side heat exchanger 35a to the use side heat exchanger 35d.

Then, the heat medium flows out from the use side heat exchanger 35a to the use side heat exchanger 35d and flows into the heat medium flow control device 34a to the heat medium flow control device 34d. At this time, the heat medium flow control device 34a to the heat medium flow control device 34d control the flow rate of the heat medium to a flow rate necessary to cover the air conditioning load required indoors, so that the use-side heat exchanger 35a. It flows into the use side heat exchanger 35d. The heat medium flowing out from the heat medium flow control device 34a to the heat medium flow control device 34d passes through the first heat medium flow switching device 32a to the first heat medium flow switching device 32d, and then the heat exchanger related to heat medium 25a. Then, the heat quantity flowing into the heat exchanger related to heat medium 25b and supplied to the indoor space 7 through the indoor unit 3 is received from the refrigerant side and sucked into the pump 31a and the pump 31b again.

[Cooling and heating mixed operation mode]
FIG. 5 is a refrigerant circuit diagram illustrating a refrigerant flow when the air-conditioning apparatus 100 is in the cooling / heating mixed operation mode. In FIG. 5, among the cooling and heating mixed operation in which the thermal load is generated in any one of the use side heat exchangers 35 and the cooling load is generated in the rest of the use side heat exchangers 35. The heating main operation mode will be described. In addition, in FIG. 5, the pipe | tube represented by the thick line has shown the piping through which the heat source side refrigerant | coolant circulates. Further, in FIG. 5, the flow direction of the heat source side refrigerant is indicated by solid line arrows, and the flow direction of the heat medium is indicated by broken line arrows.

In the heating main operation mode shown in FIG. 5, in the outdoor unit 1, the first refrigerant flow switching device 11 is connected to the relay unit without passing the heat source side refrigerant discharged from the compressor 10 through the heat source side heat exchanger 12. Switch to 2 In the relay unit 2, the pump 31a and the pump 31b are driven to open the heat medium flow rate adjusting device 34a to the heat medium flow rate adjusting device 34d, and the heat exchange between the heat medium heat exchanger 25a and the use side heat exchange in which the heat load is generated. The heat medium circulates between the heat exchanger 35 and the heat exchanger 35b between the heat medium and the use side heat exchanger 35 where the heat load is generated. The second refrigerant flow switching device 28a is switched to the cooling side, the second refrigerant flow switching device 28b is switched to the heating side, the expansion device 26a is fully opened, the opening / closing device 27 is closed, and the opening / closing device 29 is closed. ing.

First, the flow of the heat source side refrigerant in the refrigerant circuit A will be described.
The low-temperature and low-pressure refrigerant is compressed by the compressor 10 and discharged as a high-temperature and high-pressure gas refrigerant. The high-temperature and high-pressure gas refrigerant discharged from the compressor 10 passes through the first refrigerant flow switching device 11, conducts through the refrigerant connection pipe 4 a, passes through the check valve 13 d, and flows out of the outdoor unit 1. The high-temperature and high-pressure gas refrigerant that has flowed out of the outdoor unit 1 flows into the relay unit 2 through the refrigerant pipe 4. The high-temperature and high-pressure gas refrigerant that has flowed into the relay unit 2 flows through the second refrigerant flow switching device 28b into the heat exchanger related to heat medium 25b that acts as a condenser.

The gas refrigerant flowing into the heat exchanger related to heat medium 25b is condensed and liquefied while dissipating heat to the heat medium circulating in the heat medium circuit B, and becomes liquid refrigerant. The liquid refrigerant flowing out of the heat exchanger related to heat medium 25b is expanded by the expansion device 26b and becomes a low-pressure two-phase refrigerant. This low-pressure two-phase refrigerant flows into the heat exchanger related to heat medium 25a acting as an evaporator via the expansion device 26a. The low-pressure two-phase refrigerant that has flowed into the heat exchanger related to heat medium 25a evaporates by absorbing heat from the heat medium circulating in the heat medium circuit B, thereby cooling the heat medium. The low-pressure two-phase refrigerant flows out of the heat exchanger related to heat medium 25a, flows out of the relay unit 2 through the second refrigerant flow switching device 28a, and flows into the outdoor unit 1 again through the refrigerant pipe 4.

The low-temperature and low-pressure two-phase refrigerant that has flowed into the outdoor unit 1 flows into the heat source side heat exchanger 12 that acts as an evaporator through the check valve 13b. And the refrigerant | coolant which flowed into the heat source side heat exchanger 12 absorbs heat from external air in the heat source side heat exchanger 12, and turns into a low temperature and low pressure gas refrigerant. The low-temperature and low-pressure gas refrigerant flowing out from the heat source side heat exchanger 12 is again sucked into the compressor 10 via the first refrigerant flow switching device 11 and the accumulator 19.

The opening degree of the expansion device 26b is controlled so that the subcooling (supercooling degree) of the outlet refrigerant of the heat exchanger related to heat medium 25b becomes a target value. Note that the expansion device 26b may be fully opened, and the subcool may be controlled by the expansion device 26a.

Next, the flow of the heat medium in the heat medium circuit B will be described.
In the heating main operation mode, the heat of the heat source side refrigerant is transmitted to the heat medium in the heat exchanger related to heat medium 25b, and the heated heat medium is caused to flow in the pipe 5 by the pump 31b. Further, in the heating main operation mode, the cold heat of the heat source side refrigerant is transmitted to the heat medium by the heat exchanger related to heat medium 25a, and the cooled heat medium is caused to flow in the pipe 5 by the pump 31a. The cooled heat medium that has been pressurized and flowed out by the pump 31a flows into the use-side heat exchanger 35 where the cold load is generated via the second heat medium flow switching device 33, and is pressurized by the pump 31b. The heat medium that has flowed out then flows through the second heat medium flow switching device 33 into the use side heat exchanger 35 where the heat load is generated.

At this time, when the connected indoor unit 3 is in the heating operation mode, the second heat medium flow switching device 33 is switched to the direction in which the heat exchanger related to heat medium 25b and the pump 31b are connected, When the connected indoor unit 3 is in the cooling operation mode, the indoor unit 3 is switched to the direction in which the heat exchanger related to heat medium 25a and the pump 31a are connected. That is, the second heat medium flow switching device 33 can switch the heat medium supplied to the indoor unit 3 between heating and cooling.

In the use side heat exchanger 35, the cooling operation of the indoor space 7 by the heat medium absorbing heat from the room air or the heating operation of the indoor space 7 by the heat medium radiating heat to the room air is performed. At this time, the flow rate of the heat medium is controlled to a flow rate necessary to cover the air conditioning load required indoors by the action of the heat medium flow control device 34 and flows into the use side heat exchanger 35. Yes.

The heat medium that has been used for cooling operation and that has passed through the use-side heat exchanger 35 and has slightly increased in temperature passes through the heat medium flow control device 34 and the first heat medium flow switching device 32, and then the heat exchanger between heat media. It flows into 25a and is sucked into the pump 31a again. The heat medium that has been used for heating operation and has passed through the use-side heat exchanger 35 and has slightly decreased in temperature passes through the heat medium flow control device 34 and the first heat medium flow switching device 32, and then the heat exchanger between heat media. It flows into 25b and is sucked into the pump 31a again. At this time, the first heat medium flow switching device 32 is switched to the direction in which the heat exchanger related to heat medium 25b and the pump 31b are connected when the connected indoor unit 3 is in the heating operation mode, When the connected indoor unit 3 is in the cooling operation mode, the indoor unit 3 is switched to the direction in which the heat exchanger related to heat medium 25a and the pump 31a are connected.

During this time, the warm heat medium and the cold heat medium are not mixed by the action of the first heat medium flow switching device 32 and the second heat medium flow switching device 33, and the use side has a heat load and a heat load, respectively. It is introduced into the heat exchanger 35. As a result, the heat medium used in the heating operation mode receives heat from the refrigerant as a heating application, and the heat medium used in the cooling operation mode receives heat from the heat medium heat exchanger 25b. The

heat exchangers

25a, 25a, 25a, 25a, 25c, 25c, 25c, 25c, and 25b are exchanged with the refrigerant, and then are transferred to the pump 31a and the pump 31b.

In the pipe 5 of the use side heat exchanger 35, the first heat medium flow switching device 32 via the heat medium flow control device 34 from the second heat medium flow switching device 33 on both the heating side and the cooling side. The heat medium is flowing in the direction to The air conditioning load required in the indoor space 7 is the difference between the temperature detected by the temperature sensor 40b on the heating side and the temperature of the heat medium flowing out from the use side heat exchanger 35 on the cooling side. This can be covered by controlling the difference between the temperature of the heat medium flowing out from the use side heat exchanger 35 and the temperature detected by the temperature sensor 40a as a target value.

Further, in the air-conditioning apparatus 100 in FIG. 5, in the cooling / heating mixed operation mode, a cooling load is generated in one of the use side heat exchangers 35, and the remaining heat of the use side heat exchanger 35 is a heating load. Among the mixed operations that are occurring, even in the cooling main operation mode, the flow of the heat source side refrigerant in the refrigerant circuit A and the flow of the heat medium in the heat medium circuit B are the same as in the heating main operation mode.

[Defrost operation mode]
As described above, in the air conditioner 100, when the heating only operation mode or the heating main operation mode is performed, the heat source side heat exchanger 12 in the outdoor unit 1 serves as an evaporator and performs heat exchange with the outside air. Therefore, when the outside air is low, the evaporation temperature of the heat source side heat exchanger 12 becomes lower, and the moisture of the outside air is frosted on the surface of the heat source side heat exchanger 12, which may reduce the heat exchange performance. It is done. Therefore, in the air conditioner 100, the outdoor unit 1 detects the evaporating temperature, for example, and when the detected evaporating temperature becomes too low, the defrosting operation mode for removing the frost on the surface of the heat source side heat exchanger 12 is performed. Like to do. The heating only operation mode and the heating main operation mode correspond to the “heating operation mode” of the present invention.

In the air conditioner 100, when the defrosting operation mode is carried out, the heat capacity that the heat medium had in the previous heating operation can be used. That is, the air conditioner 100 switches the first refrigerant flow switching device 11 to the cooling side during the heating operation mode, operates at least one of the pumps 31, and operates in at least one of the heat exchangers related to heat medium 25. The refrigerant absorbs the heat held by the heat medium and melts the frost formed around the heat source side heat exchanger 12 (heat recovery defrosting operation mode). By carrying out like this, in the air conditioning apparatus 100, it is possible to remove the frost of the surface of the heat source side heat exchanger 12 more rapidly than before. On the other hand, in the air conditioning apparatus 100, the heating operation mode in the use side heat exchanger 35 can be continued.

Further, in the air conditioner 100, during the heating operation mode, the first refrigerant flow switching device 11 is switched to the cooling side, and a part or all of the refrigerant flows through the bypass pipe 20 to surround the heat source side heat exchanger 12. It has a bypass defrosting operation mode that melts frost that has formed on the surface.

In order to perform the operation as described above, in the air conditioning apparatus 100, the temperature of the heat medium is raised through the heat exchanger related to heat medium 25 during the heating operation mode immediately before the defrosting operation mode is performed. And in the air conditioning apparatus 100, after detecting that the temperature of the raised heat medium detected by the temperature sensor 40 is higher than a set temperature (for example, 43 ° C.), the defrosting operation mode is performed. . By carrying out like this, the air conditioning apparatus 100 can ensure the heat capacity | capacitance for utilizing for a defrost operation mode, and the calorie | heat amount for continuing heating operation mode.

Specifically, when the temperature of the heat medium detected by the temperature sensor 40 is higher than a set temperature (for example, 43 ° C.), the air conditioner 100 uses the heat capacity possessed by the heat medium to perform “heat recovery defrosting operation”. Mode ". On the other hand, when the temperature of the heat medium detected by the temperature sensor 40 is lower than a set temperature (for example, 43 ° C.), the air conditioner 100 performs the “bypass defrosting operation mode” that does not use the heat capacity of the heat medium. . The set temperature can be changed to an arbitrary temperature. However, the set temperature may include a usage-side air temperature detection device that detects the temperature of the air that is ventilated to the usage-side heat exchanger 35, and may be a value that is equal to or higher than the temperature detected by the usage-side air temperature detection device. preferable. If the temperature is set to such a temperature, either the “heat recovery defrosting operation mode” or the “bypass defrosting operation mode” can be executed while maintaining comfort.

As described above, the defrosting operation mode performed by the air conditioner 100 includes two types of defrosting operation modes (“heat recovery defrosting operation mode” and “bypass defrosting operation mode” corresponding to the flow of the heat source side refrigerant. ]).
The “heat recovery defrosting operation mode” performed during the heating only operation mode will be referred to as a “first heat recovery defrosting operation mode”.
The “heat recovery defrosting operation mode” performed during the heating main operation mode is referred to as a “second heat recovery defrosting operation mode”.
The “bypass defrosting operation mode” performed during the heating only operation mode will be referred to as a “first bypass defrosting operation mode”.
The “bypass defrosting operation mode” performed during the heating main operation mode is referred to as “second bypass defrosting operation mode”.

[First heat recovery defrosting operation mode]
The “first heat recovery defrosting operation mode” performed during the heating only operation mode of the air-conditioning apparatus 100 further includes two types of defrosting operation modes (“first heat recovery operation” depending on the flow of the heat source side refrigerant. Defrosting operation mode (1) "," first heat recovery defrosting operation mode (2) ").

(First heat recovery defrosting operation mode (1))
FIG. 6 is a refrigerant circuit diagram illustrating a refrigerant flow and a heat medium flow when the air-conditioning apparatus 100 is in the “first heat recovery defrosting operation mode (1)”. In FIG. 6, the “first heat recovery defrosting operation mode (1)” will be described. In addition, in FIG. 6, the piping represented by the thick line has shown the piping through which the heat source side refrigerant | coolant circulates. In FIG. 6, the flow direction of the heat source side cooling is indicated by solid line arrows, and the flow direction of the heat medium is indicated by broken line arrows.

In the “first heat recovery defrosting operation mode (1)”, during the heating only operation mode of the air conditioner 100, moisture in the outside air is frosted on the heat source side heat exchanger 12 in the outdoor unit 1, This is a defrosting operation mode performed when the evaporation temperature is lowered.

In the case of the “first heat recovery defrosting operation mode (1)” shown in FIG. 6, in the outdoor unit 1, heat source side refrigerant discharged from the compressor 10 through the first refrigerant flow switching device 11 is heat exchanged on the heat source side. Switch to flow into vessel 12.

In the relay unit 2, the pump 31a and the pump 31b are driven, the heat medium flow control devices 34a to 34d are opened, and the heat medium heat exchanger 25a and the heat medium heat exchanger 25b are used respectively. The heat medium circulates between the side heat exchanger 35a and the use side heat exchanger 35d. The second refrigerant flow switching device 28a and the second refrigerant flow switching device 28b are switched to the cooling side, the opening / closing device 27 is open, and the opening / closing device 29 is closed. Further, the expansion device 26a and the expansion device 26b are fully opened. The diaphragm device 26a and the diaphragm device 26b do not have to be fully opened.

First, the flow of the heat source side refrigerant in the refrigerant circuit A will be described.
The low-temperature and low-pressure refrigerant is compressed by the compressor 10 and discharged as a high-temperature and high-pressure gas refrigerant. The high-temperature and high-pressure gas refrigerant discharged from the compressor 10 passes through the first refrigerant flow switching device 11 and flows into the heat source side heat exchanger 12. The refrigerant flowing into the heat source side heat exchanger 12 exchanges heat with the frosting part on the heat source side heat exchanger 12. The frosting part on the heat source side heat exchanger 12 is melted by the high-temperature and high-pressure refrigerant. The low-temperature and high-pressure refrigerant that has exchanged heat with the frosting section on the heat source side heat exchanger 12 flows out of the outdoor unit 1 after passing through the check valve 13a. The low-temperature and high-pressure refrigerant that has flowed out of the outdoor unit 1 flows into the relay unit 2 through the refrigerant pipe 4.

The refrigerant that has flowed into the relay unit 2 passes through the opening / closing device 27, is branched, passes through the expansion device 26a and the expansion device 26b, and flows into the intermediate heat exchanger 25a and the intermediate heat exchanger 25b. The low-temperature and high-pressure refrigerant that has flowed into the heat exchanger related to heat medium 25a and the heat exchanger related to heat medium 25b exchanges heat with the heat medium that has been used until now to become a high-temperature and high-pressure refrigerant. The refrigerant flowing out of the heat exchanger related to heat medium 25a and the heat exchanger related to heat medium 25b flows out of the relay unit 2 through the second refrigerant flow switching device 28a and the second refrigerant flow switching device 28b, and is connected to the refrigerant piping. 4, passes through the check valve 13 c, and is sucked again into the compressor 10 through the first refrigerant flow switching device 11 and the accumulator 19.

(First heat recovery defrosting operation mode (2))
FIG. 7 is a refrigerant circuit diagram illustrating a refrigerant flow and a heat medium flow when the air-conditioning apparatus 100 is in the “first heat recovery defrosting operation mode (2)”. In FIG. 7, the “first heat recovery defrosting operation mode (2)” will be described. In addition, in FIG. 7, the piping represented by the thick line has shown the piping through which the heat source side refrigerant | coolant circulates. In FIG. 7, the flow direction of the heat source side cooling is indicated by solid line arrows, and the flow direction of the heat medium is indicated by broken line arrows.

The “first heat recovery defrosting operation mode (2)” is the same as the “first heat recovery defrosting operation mode (1)”. This is a defrosting operation mode that is performed when moisture in the outside air is frosted on the heat source side heat exchanger 12 and the evaporation temperature is lowered. However, in the “first heat recovery defrosting operation mode (2)”, the flow of the heat source side refrigerant is different from that in the “first heat recovery defrosting operation mode (1)”. In the air conditioner 100, either the “first heat recovery defrosting operation mode (1)” or the “first heat recovery defrosting operation mode (2)” can be selected.

In the “first heat recovery defrosting operation mode (2)” shown in FIG. 7, in the outdoor unit 1, the heat source side refrigerant discharged from the compressor 10 is used as the heat source side heat exchange in the first refrigerant flow switching device 11. Switch to flow into vessel 12.

In the relay unit 2, the pump 31a and the pump 31b are driven, the heat medium flow control devices 34a to 34d are opened, and the heat medium heat exchanger 25a and the heat medium heat exchanger 25b are used respectively. The heat medium circulates between the side heat exchanger 35a and the use side heat exchanger 35d. The second refrigerant flow switching device 28a and the second refrigerant flow switching device 28b both maintain the opening direction on the heating side, the opening / closing device 27 is closed, and the opening / closing device 29 is open. Further, the

expansion devices

26a and 26b are fully opened. The diaphragm device 26a and the diaphragm device 26b do not have to be fully opened.

The low-temperature and high-pressure gas refrigerant that has flowed into the relay unit 2 is branched and passes through the second refrigerant flow switching device 28a and the second refrigerant flow switching device 28b, and the heat exchanger related to heat medium 25a and heat between the heat media. It flows into each of the exchangers 25b. The low-temperature and high-pressure refrigerant that has flowed into the heat exchanger related to heat medium 25a and the heat exchanger related to heat medium 25b exchanges heat with the heat medium that has been used until now to become a high-temperature and high-pressure refrigerant. The refrigerant that has flowed out of the heat exchanger related to heat medium 25a and the heat exchanger related to heat medium 25b passes through the expansion device 26a and the expansion device 26b, flows out of the relay unit 2 via the opening / closing device 29, and is conducted through the refrigerant pipe 4. Then, it passes through the check valve 13 c and is sucked again into the compressor 10 through the first refrigerant flow switching device 11 and the accumulator 19.

Next, the flow of the heat medium in the heat medium circuit B in the “first heat recovery defrosting operation mode” will be described. In addition, the flow of the heat medium in the heat medium circuit B includes “first heat recovery defrosting operation mode (1)” shown in FIG. 6 and “first heat recovery defrosting operation mode ( 2) ". Therefore, hereinafter, the flow of the heat medium will be described by taking the “first heat recovery defrosting operation mode (2)” as an example.

In the “first heat recovery defrosting operation mode (2)”, the heat medium exchanges heat with the low-temperature and high-pressure gas refrigerant in both the heat exchangers between

heat exchangers

25a and 25b, It becomes a low-temperature heat medium. The heat medium that has been cooled to a low temperature by the heat exchanger related to heat medium 25a and the heat exchanger related to heat medium 25b is pressurized by the pump 31a and the pump 31b, and the second heat medium flow switching device 33a to the second heat medium flow path. It flows into the use side heat exchanger 35a to the use side heat exchanger 35d via the switching device 33d. At this time, the second heat medium flow switching device 33 has an intermediate opening degree so that the heat medium conveyed from both the heat exchangers between

heat exchangers

25a and 25b can be supplied to the indoor unit 3. Or it adjusts to the opening degree according to the heat medium temperature of the exit of the heat exchanger 25a between heat media, and the heat exchanger 25b between heat media.

Then, the heat medium flows out from the use side heat exchanger 35a to the use side heat exchanger 35d and flows into the heat medium flow control device 34a to the heat medium flow control device 34d. The heat medium flowing out from the heat medium flow control device 34a to the heat medium flow control device 34d passes through the first heat medium flow switching device 32a to the first heat medium flow switching device 32d. At this time, the opening degree of the first heat medium flow switching device 32 is adjusted in the same manner as the second heat medium flow switching device 33, and the heat medium flow control device 34 is fully opened.

The heat medium that has passed through the first heat medium flow switching device 32a to the first heat medium flow switching device 32d flows into the heat exchanger related to heat medium 25a and the heat exchanger related to heat medium 25b, and again heat between the heat medium. Heat exchange is performed with the refrigerant flowing through the exchanger 25a and the heat exchanger related to heat medium 25b, and after supplying heat to the refrigerant side, the refrigerant is sucked into the pump 31a and the pump 31b again.

In addition, the indoor unit 3 that has been performing the heating operation so far in the “first heat recovery defrosting operation mode” receives information that the outdoor unit 1 is in the defrosting operation mode, and uses the heat exchanger on the use side. A blower (hereinafter simply referred to as a fan) for blowing air to 35 is stopped. However, if the indoor air temperature and the indoor unit blown air temperature can be detected, there is no problem even if the fan operation is continued until the indoor unit blown air temperature does not become lower than the indoor air temperature. Further, as long as the heat medium temperature at the outlet of the heat exchanger related to heat medium 25 detected by the temperature sensor 40 does not become lower than the indoor air temperature, the fan operation may be continued.

Thus, during the “first heat recovery defrosting operation mode” of the outdoor unit 1, heat exchange with the heat medium in the heat exchanger related to heat medium 25a and the heat exchanger related to heat medium 25b in the relay unit 2 is performed. By performing, the amount of heat given from the heat medium to the refrigerant side can be supplied to the heat source side heat exchanger 12 of the outdoor unit 1, and the frost melting time can be shortened.

[Second heat recovery defrosting operation mode]
FIG. 8 is a refrigerant circuit diagram illustrating the refrigerant flow and the heat medium flow when the air-conditioning apparatus 100 is in the “second heat recovery defrosting operation mode”. In FIG. 8, the “second heat recovery defrosting operation mode” will be described. In addition, in FIG. 8, the pipe | tube represented by the thick line has shown the piping through which the heat source side refrigerant | coolant circulates. In FIG. 8, the flow direction of the heat source side cooling is indicated by a solid line arrow, and the flow direction of the heat medium is indicated by a broken line arrow.

In the “second heat recovery defrosting operation mode” shown in FIG. 8, in the outdoor unit 1, the heat source side refrigerant discharged from the compressor 10 in the first refrigerant flow switching device 11 is transferred to the heat source side heat exchanger 12. Switch to allow inflow.

In the relay unit 2, the pump 31 a and the pump 31 b are driven, the heat medium flow control device 34 for the indoor unit 3 that is performing the cooling operation is opened, and the cooling operation is performed with the inter-heat medium heat exchanger 25 a. The heat medium circulates between the indoor unit 3 and the use side heat exchanger 35, the heat medium flow control device 34 for the indoor unit 3 that is performing the heating operation is fully opened, and the heat exchanger 25b between heat mediums. The heat medium circulates between the heat exchanger 35 and the use side heat exchanger 35 of the indoor unit 3 performing the heating operation. Further, both the second refrigerant flow switching device 28a and the second refrigerant flow switching device 28b maintain the opening direction on the cooling side, the opening / closing device 27 is open, and the opening / closing device 29 is closed. Further, the expansion device 26a is controlled so that the refrigerant state at the outlet of the heat exchanger related to heat medium 25a becomes gas, and the expansion device 26b is fully opened. The diaphragm device 26b does not have to be fully open.

The refrigerant that has flowed into the relay unit 2 passes through the opening / closing device 27, is branched, passes through the expansion device 26a and the expansion device 26b, and flows into the intermediate heat exchanger 25a and the intermediate heat exchanger 25b. In the heat exchanger related to heat medium 25a, heat exchange with the heat medium is continued by the action of the expansion device 26a, and a low-temperature heat medium for cooling is generated and supplied to the indoor unit 3. On the other hand, the heat source side refrigerant that has lost its heat capacity due to the defrosting of the heat source side heat exchanger 12 is conveyed to the heat exchanger related to heat medium 25b, and heat exchange with the high temperature heat medium that has been in the heating operation until then. By carrying out, it is possible to ensure the heat capacity.

The refrigerant flowing out of the heat exchanger related to heat medium 25a and the heat exchanger related to heat medium 25b flows out of the relay unit 2 through the second refrigerant flow switching device 28a and the second refrigerant flow switching device 28b, and is connected to the refrigerant piping. 4, passes through the check valve 13 c, and is sucked again into the compressor 10 through the first refrigerant flow switching device 11 and the accumulator 19.

Next, the flow of the heat medium in the heat medium circuit B in the “second heat recovery defrosting operation mode” will be described.

In the “second heat recovery defrosting operation mode”, the heat medium lowered in temperature by the intermediate heat exchanger 25a and the heat medium lowered in the intermediate heat exchanger 25b are the pump 31a and the pump 31b. And flows into the use side heat exchanger 35a to the use side heat exchanger 35d via the second heat medium flow switching device 33a to the second heat medium flow switching device 33d. At this time, the second heat medium flow switching device 33 switches to the direction in which the heat exchanger related to heat medium 25b and the pump 31b are connected when the connected indoor unit 3 is in the heating operation mode. When the connected indoor unit 3 is in the cooling operation mode, it is switched to the direction in which the heat exchanger related to heat medium 25a and the pump 31a are connected.

The heat medium flowing into the indoor unit 3 by the pump 31a is cooled by exchanging heat with the indoor air in the indoor space 7 by the use side heat exchanger 35 with respect to the indoor unit 3 that has been performing the cooling operation until then. Continue driving. Then, the heat medium exchanged by the use side heat exchanger 35 passes through the heat medium pipe 5 and the heat medium flow control device 34 and is conveyed into the relay unit 2. The flow rate of the heat medium transported to each indoor unit 3 is adjusted by each heat medium flow control device 34. The heat medium flowing out from the heat medium flow control device 34 passes through the first heat medium flow switching device 32.

At this time, the heat medium flow control device 34 detects the difference between the temperature immediately before the pump 31a and the outlet temperature of the connected indoor unit 3 to adjust the flow rate. The first heat medium flow switching device 32 is switched in the direction in which the heat exchanger related to heat medium 25a and the pump 31a are connected.

On the other hand, the pump 31b is driven, but the fan of the indoor unit 3 that has been in the heating operation mode is stopped, and the heating operation mode is stopped. Moreover, in the 2nd heat-medium flow-path switching apparatus 33 connected to the indoor unit 3 which has been implementing heating operation mode until then, it has faced the opening degree direction to which the pump 31b is connected. Further, the heat medium flow control device 34 after passing through the use side heat exchanger 35 is fully opened, and the first heat medium flow switching device 32 has the same opening as the second heat medium flow switching device 33.

The heat medium transported to the indoor unit 3 that has been in the heating operation mode is not subjected to heat exchange in the use side heat exchanger 35, and is transferred to the heat exchanger related to heat medium 25b through the first heat medium flow switching device 32. It is conveyed. The heat medium flowing into the heat exchanger related to heat medium 25b is again heat-exchanged with the heat source side refrigerant flowing into the heat exchanger related to heat medium 25b, and supplies heat to the refrigerant. Thereafter, the heat medium is again sucked into the pump 31b.

In addition, the indoor unit 3 that has been performing the heating operation so far in the “second heat recovery defrosting operation mode” receives information that the outdoor unit 1 is in the defrosting operation mode, and stops the fan. However, if the indoor air temperature and the indoor unit blown air temperature can be detected, there is no problem even if the fan operation is continued until the indoor unit blown air temperature does not become lower than the indoor air temperature. Further, as long as the heat medium temperature at the outlet of the heat exchanger related to heat medium 25 detected by the temperature sensor 40 does not become lower than the indoor air temperature, the fan operation may be continued.

[First bypass defrosting operation mode]
FIG. 9 is a refrigerant circuit diagram illustrating a refrigerant flow and a heat medium flow when the air-conditioning apparatus 100 is in the “first bypass defrosting operation mode”. In FIG. 9, the “first bypass defrosting operation mode” will be described. In addition, in FIG. 9, the pipe | tube represented by the thick line has shown the piping through which the heat source side refrigerant | coolant circulates. In FIG. 9, the flow direction of the heat source side cooling is indicated by solid line arrows, and the flow direction of the heat medium is indicated by broken line arrows.

The “first bypass defrosting operation mode” is the same as the “first heat recovery defrosting operation mode”, during the heating only operation mode of the air conditioner 100, the heat source side heat exchanger 12 in the outdoor unit 1. However, unlike the “first heat recovery defrosting operation mode”, the heat capacity from the heat medium is reduced to the refrigerant. Is not allowed to receive. The “first bypass defrosting operation mode” is switched and executed in accordance with a change in the set temperature during the execution of the “first heat recovery defrosting operation mode”.

In the “first bypass defrosting operation mode” shown in FIG. 9, in the outdoor unit 1, the heat source side refrigerant discharged from the compressor 10 flows into the heat source side heat exchanger 12 through the first refrigerant flow switching device 11. Switch to let

In the relay unit 2, the pump 31a and the pump 31b are driven, the heat medium flow control devices 34a to 34d are opened, and the heat medium heat exchanger 25a and the heat medium heat exchanger 25b are used respectively. The heat medium circulates between the side heat exchanger 35a and the use side heat exchanger 35d. Further, the second refrigerant flow switching device 28a and the second refrigerant flow switching device 28b maintain the state switched to the cooling side, the opening / closing device 27 is open, and the opening / closing device 29 is open. Further, the expansion device 26a and the expansion device 26b are fully closed.

The refrigerant flowing into the relay unit 2 passes through the switchgear 29 after passing through the switchgear 27. Since the expansion device 26a and the expansion device 26b are fully closed, no refrigerant is conveyed to the intermediate heat exchanger 25a and the intermediate heat exchanger 25b. The refrigerant that has passed through the opening / closing device 29 flows out of the relay unit 2 as it is, and flows into the outdoor unit 1 through the refrigerant pipe 4. The refrigerant flowing into the outdoor unit 1 passes through the check valve 13 c and is sucked into the compressor 10 again through the first refrigerant flow switching device 11 and the accumulator 19.

Next, the flow of the heat medium in the heat medium circuit B in the “first bypass defrosting operation mode” will be described.

The heat medium has been in a heating operation until then, and as described above, the heat medium is temporarily heated in the heat medium heat exchanger 25 before performing the defrosting operation mode. Therefore, the high temperature is maintained. Therefore, even during the defrosting operation mode, a high-temperature heat medium can be conveyed to the use-side heat exchanger 35, that is, the heating operation can be continued in the indoor unit 3.

Specifically, the heat medium is conveyed by the operation of the pump 31a and the pump 31b connected to the heat exchanger related to heat medium 25a and the heat exchanger related to heat medium 25b. Further, the second heat medium flow switching device 33 connected to each indoor unit 3 has an intermediate opening degree. Further, the heat medium flow control device 34 is controlled so that the outlet temperature of the intermediate heat exchanger 25 and the outlet temperature of the use side heat exchanger 35 are constant. The first heat medium flow switching device 32 has the same opening degree as that of the second heat medium flow switching device 33, and the heating operation by the heat medium conveyance can be continued.

In addition, as shown in FIG. 9, even when the indoor unit 3 can be ventilated, a high-temperature heat medium can flow into the use-side heat exchanger 35 during the defrosting operation. Thus, heat exchange with the outside air by the operation of the fan is possible, and the heating operation by hot air blowing can be continued.

When the heating operation is continued by the operation of the fan, the air volume of the fan is reduced as compared with the fan air volume (the set air volume) at the time of the conventional heating operation, so that the use side heat exchanger 35 enters the indoor space. The heat capacity to be released can be limited, and the holding time of the heat capacity of the heat medium can be extended. In addition, the setting air volume which is the air volume of the fan at the time of the conventional heating operation can be changed.

FIG. 10 is a graph showing an example of the relationship between the fan air volume for each temperature difference at which the heat medium can be lowered and the heat medium temperature holdable time when the heating operation is continued with the air volume. As shown in FIG. 10, it is possible to estimate the amount of heat released to the indoor space by the air blown from the fan and the time with respect to the heat capacity that the heat medium can hold. By doing so, it is possible to determine an appropriate air volume ratio and air volume holding time, and to continue the heating operation mode at an appropriate time and temperature in the defrosting operation mode.

[Second bypass defrosting operation mode]
FIG. 11 is a refrigerant circuit diagram illustrating a refrigerant flow and a heat medium flow when the air-conditioning apparatus 100 is in the “second bypass defrosting operation mode”. In FIG. 11, “second bypass defrosting operation mode” will be described. In addition, in FIG. 11, the piping represented by the thick line has shown the piping through which the heat source side refrigerant | coolant circulates. In FIG. 11, the flow direction of the heat source side cooling is indicated by solid line arrows, and the flow direction of the heat medium is indicated by broken line arrows. The “second bypass defrosting operation mode” is switched and executed in accordance with a change in the set temperature during the execution of the “second heat recovery defrosting operation mode”.

In the “second bypass defrosting operation mode” shown in FIG. 11, in the outdoor unit 1, the heat source side refrigerant discharged from the compressor 10 flows into the heat source side heat exchanger 12 through the first refrigerant flow switching device 11. Switch to let

In the relay unit 2, the pump 31a and the pump 31b are driven, the heat medium flow control devices 34a to 34d are opened, and the heat medium heat exchanger 25a and the heat medium heat exchanger 25b are used respectively. The heat medium circulates between the side heat exchanger 35a and the use side heat exchanger 35d. Further, the second refrigerant flow switching device 28a and the second refrigerant flow switching device 28b maintain the state switched to the cooling side, the opening / closing device 27 is open, and the opening / closing device 29 is open. Further, the expansion device 26a is controlled such that the refrigerant state at the outlet of the heat exchanger related to heat medium 25a is gas, and the expansion device 26b is fully closed.

The refrigerant that has flowed into the relay unit 2 passes through the opening / closing device 27 and then branches to pass through the opening / closing device 29 and the expansion device 26a. The refrigerant that has passed through the expansion device 26a flows into the heat exchanger related to heat medium 25a. In the heat exchanger related to heat medium 25a, heat exchange with the heat medium is continued by the action of the expansion device 26a, and a low-temperature heat medium for cooling is generated and supplied to the indoor unit 3. On the other hand, the refrigerant is not conveyed to the heat exchanger related to heat medium 25b, and heat exchange with the high-temperature heat medium that has been performed until then is not performed.

The refrigerant that has passed through the heat exchanger related to heat medium 25a and the switching device 29 flows out of the relay unit 2 after joining. The refrigerant flowing out from the relay unit 2 flows into the outdoor unit through the refrigerant pipe 4. The refrigerant flowing into the outdoor unit 1 passes through the check valve 13 c and is sucked into the compressor 10 again through the first refrigerant flow switching device 11 and the accumulator 19.

Next, the flow of the heat medium in the heat medium circuit B in the “second bypass defrosting operation mode” will be described.

In the “second bypass defrosting operation mode”, the heat medium having a low temperature in the intermediate heat exchanger 25a is pressurized by the pump 31a and corresponds to the indoor unit 3 in the cooling operation mode. It flows into the use side heat exchanger 35a to the use side heat exchanger 35d via the flow path switching device 33a to the second heat medium flow switching device 33d. The heat medium flowing into the indoor unit 3 by the pump 31a is cooled by exchanging heat with the indoor air in the indoor space 7 by the use side heat exchanger 35 with respect to the indoor unit 3 that has been performing the cooling operation until then. Continue driving.

Then, the heat medium exchanged by the use side heat exchanger 35 passes through the heat medium pipe 5 and the heat medium flow control device 34 and is conveyed into the relay unit 2. The flow rate of the heat medium transported to each indoor unit 3 is adjusted by each heat medium flow control device 34. The heat medium flowing out from the heat medium flow control device 34 passes through the first heat medium flow switching device 32. The heat medium that has passed through the first heat medium flow switching device 32 is again heat-exchanged with the heat source side refrigerant flowing into the heat exchanger related to heat medium 25a, and supplies heat to the refrigerant side. Thereafter, the heat medium is again sucked into the pump 31a.

On the other hand, the heat medium flowing into the heat exchanger related to heat medium 25b is heated in the heating operation until then, and as described above, the heat medium is heated in the heat exchanger related to heat medium before performing the defrosting operation mode. Since the heat capacity is secured by temporarily raising the temperature of the medium, the medium is kept at a high temperature. Therefore, even in the defrosting operation mode, the high-temperature heat medium can be conveyed to the use-side heat exchanger 35 by the conveyance of the heat medium, that is, the heating operation can be continued in the indoor unit 3. .

Specifically, the heat medium is conveyed by the operation of the pump 31b connected to the heat exchanger related to heat medium 25b. Further, the second heat medium flow switching device 33 connected to each indoor unit 3 faces the heat exchanger related to heat medium 25b. Furthermore, the heat medium flow control device 34 after passing through the use side heat exchanger 35 is controlled so that the outlet temperature of the heat exchanger related to heat medium 25b and the outlet temperature of the use side heat exchanger are constant. Further, the first heat medium flow switching device 32 has the same opening as the second heat medium flow switching device 33, and the heating operation by heat medium conveyance can be continued.

In addition, as shown in FIG. 11, even when the indoor unit 3 can be ventilated, a high-temperature heat medium can flow into the use-side heat exchanger 35 during the defrosting operation. Thus, heat exchange with the outside air by the operation of the fan is possible, and the heating operation by hot air blowing can be continued.

In addition, as explained based on FIG. 10, when the heating operation is continued by the operation of the fan, the air volume of the fan is reduced as compared with the conventional heating operation, so that the indoor space is used in the use side heat exchanger 35. It is possible to limit the heat capacity to be released to the heat source, and to extend the heat capacity retention time of the heat medium.

As described above, the air-conditioning apparatus 100 exchanges heat between the refrigerant and the heat medium via the relay unit 2 without directly circulating the refrigerant in the room where the indoor unit 3 is installed. Cooling operation and heating operation are realized by conveying to the indoor unit 3. Thereby, the air conditioning apparatus 100 can avoid refrigerant leakage into the room. In addition, the air conditioner 100 can transfer the refrigerant from the outdoor unit 1 to the relay unit 2 so that the relay unit 2 can be installed at an appropriate position, so that the transfer distance of the heat medium can be shortened, and the pump 31a. The power of the pump 31b can be reduced to save energy.

Furthermore, when the air conditioner 100 performs the heating operation at a low outside air temperature, frost formation occurs in the outdoor unit 1, and the frost of the heat source side heat exchanger 12 in the outdoor unit 1 is detected by detection based on the evaporation temperature or the like. It has a defrosting operation mode for removing water. In this defrosting operation mode, the heat exchanged by defrosting and the refrigerant having a low temperature are conveyed to the indoor unit 3 during the heating operation, and heated to a high temperature immediately before the defrosting operation and the heat medium It is exchanged and transported to the outdoor unit 1. By carrying out like this, according to the air conditioning apparatus 100, the heat capacity which a heat carrier has can be utilized for defrosting, and defrosting operation time can be shortened.

Further, the air conditioner 100 reduces the fan air volume and sets the fan operation holding time according to the air volume for the indoor unit 3 that has been performing the heating operation until then in the defrosting operation mode. Appropriate heating operation can be continued. Furthermore, even when the indoor unit 3 can take in the outside air, the air conditioner 100 can exchange heat with the heat medium in the defrosting operation mode and continue the heating operation in the same manner as described above. Can do.

The first heat medium flow switching device 32 and the second heat medium flow switching device 33 described in the present embodiment can switch a three-way flow such as a three-way valve, and can open and close a two-way flow such as an on-off valve. What is necessary is just to be able to switch a flow path, such as combining two things to perform. In addition, the first heat medium can be obtained by combining two things such as a stepping motor drive type mixing valve that can change the flow rate of the three-way flow path and two things that can change the flow rate of the two-way flow path such as an electronic expansion valve. The flow path switching device 32 and the second heat medium flow path switching device 33 may be used. In this case, it is possible to prevent water hammer due to sudden opening and closing of the flow path. Further, in the present embodiment, the case where the heat medium flow control device 34 is a two-way valve has been described as an example, but it is a control valve having a three-way flow path and a bypass pipe that bypasses the use-side heat exchanger 35. You may make it install.

Also, the heat medium flow control device 34 may be a stepping motor driven type that can control the flow rate flowing through the flow path, and may be a two-way valve or a one-way valve with one end closed. Further, as the heat medium flow control device 34, a device that opens and closes a two-way flow path such as an open / close valve may be used, and the average flow rate may be controlled by repeating ON / OFF.

Although the second refrigerant flow switching device 28 is shown as a four-way valve, the present invention is not limited to this, and a plurality of two-way flow switching valves and three-way flow switching valves are used in the same manner. You may comprise so that a refrigerant | coolant may flow.

Moreover, it goes without saying that the same holds true even when only one use-side heat exchanger 35 and one heat medium flow control device 34 are connected. As the heat exchanger 25 between heat mediums and the expansion device 26, Of course, there is no problem even if there are multiple things that move in the same way. Further, the case where the heat medium flow control device 34 is built in the relay unit 2 has been described as an example. However, the heat medium flow control device 34 is not limited to this, and may be built in the indoor unit 3. 3 may be configured separately.

As the heat medium, for example, brine (antifreeze), water, a mixture of brine and water, a mixture of water and an additive having a high anticorrosive effect, or the like can be used. Therefore, in the air conditioning apparatus 100, even if the heat medium leaks into the indoor space 7 through the indoor unit 3, it contributes to the improvement of safety because a highly safe heat medium is used. Become.

In the present embodiment, the case where the air conditioner 100 includes the accumulator 19 has been described as an example, but the accumulator 19 may not be provided. In general, the heat source side heat exchanger 12 and the use side heat exchanger 35 are provided with a blower, and in many cases, condensation or evaporation is promoted by blowing air, but this is not a limitation. For example, the use side heat exchanger 35 can be a panel heater using radiation, and the heat source side heat exchanger 12 is a water-cooled type that moves heat by water or antifreeze. Can also be used. That is, the heat source side heat exchanger 12 and the use side heat exchanger 35 can be used regardless of the type as long as they have a structure capable of radiating heat or absorbing heat.

In the present embodiment, the case where there are four usage-side heat exchangers 35 has been described as an example, but the number is not particularly limited. Moreover, although the case where the number of heat exchangers between heat mediums 25a and the heat exchangers between heat mediums 25b is two has been described as an example, naturally the present invention is not limited to this, so that the heat medium can be cooled or / and heated. If it comprises, you may install how many. Furthermore, the number of

pumps

31a and 31b is not limited to one, and a plurality of small-capacity pumps may be connected in parallel.

1 outdoor unit, 2 relay unit, 3 indoor unit, 3a indoor unit, 3b indoor unit, 3c indoor unit, 3d indoor unit, 4 refrigerant pipe, 4a refrigerant connection pipe, 4b refrigerant connection pipe, 5 heat medium pipe, 6 Outdoor space, 7 indoor space, 8 space, 9 building, 10 compressor, 11 first refrigerant flow switching device, 12 heat source side heat exchanger, 13a check valve, 13b check valve, 13c check valve, 13d check Stop valve, 19 accumulator, 20 bypass pipe, 25 heat exchanger between heat medium, 25a heat exchanger between heat medium, 25b heat exchanger between heat medium, 26 throttle device, 26a throttle device, 26b throttle device, 27 switchgear 28 second refrigerant flow switching device (refrigerant flow switching device), 28a second refrigerant flow switching device (refrigerant flow switching device) ), 28b Second refrigerant flow switching device (refrigerant flow switching device), 29 Opening / closing device, 31 pump, 31a pump, 31b pump, 32 1st heat medium flow switching device, 32a 1st heat medium flow switching device 32b, first heat medium flow switching device, 32c, first heat medium flow switching device, 32d, first heat medium flow switching device, 33, second heat medium flow switching device, 33a, second heat medium flow switching device. 33b, second heat medium flow switching device, 33c, second heat medium flow switching device, 33d, second heat medium flow switching device, 34, heat medium flow control device, 34a, heat medium flow control device, 34b, heat medium flow control. Apparatus, 34c heat medium flow control device, 34d heat medium flow control device, 35 use side heat exchanger, 35a use side heat exchanger, 35b use side heat exchanger, 35c use side heat exchanger, 5d use side heat exchanger, 40 temperature sensor (heat medium temperature detection device), 40a temperature sensor (heat medium temperature detection device), 40b temperature sensor (heat medium temperature detection device), 43 duct, 50 control device, 100 air conditioning Equipment, A refrigerant circulation circuit, B heat medium circulation circuit.

Claims

Heat source side refrigerant by connecting a compressor, a heat source side heat exchanger, a plurality of expansion devices, a refrigerant side flow path of a plurality of heat exchangers between heat mediums, and a plurality of refrigerant flow switching devices for switching a refrigerant circulation path through a refrigerant pipe A refrigerant circulation circuit for circulating
A plurality of heat medium conveying devices provided corresponding to each of the plurality of heat exchangers between heat media, a plurality of use side heat exchangers, and a heat medium side flow path of the plurality of heat exchangers between heat media. A heat medium circulation circuit that circulates the heat medium by connecting with a heat medium conveyance pipe,
A bypass pipe installed so as to bypass at least the heat exchanger between heat media and return the heat source side refrigerant to the compressor;
An air conditioner in which heat is exchanged between the heat source side refrigerant and the heat medium in the intermediate heat exchanger.
The refrigerant flow switching device is switched to a heating side, the heat medium is heated by at least one of the heat exchangers between the heat media, and at least one of the heat medium transport devices is operated, and the use side heat A heating operation mode for supplying the heated heat medium to at least one of the exchangers;
During the heating operation mode, the refrigerant flow switching device is switched to the cooling side to operate at least one of the heat medium transport devices, and at least one of the heat exchangers related to heat medium is changed to the heat source side refrigerant. A heat recovery defrosting operation mode for absorbing heat of the heat medium and melting frost formed around the heat source side heat exchanger;
During the heating operation mode, the refrigerant flow switching device is switched to the cooling side, and frost is formed around the heat source side heat exchanger by flowing a part or all of the heat source side refrigerant to the bypass pipe. A bypass defrosting operation mode for melting the air conditioning apparatus.
In the heat recovery defrosting operation mode,
The heat exchanger related to heat medium that causes the heat source side refrigerant to absorb heat of the heat medium is,
The air conditioner according to claim 1, wherein the heat exchanger is the same as the heat exchanger related to heat medium that heats the heat medium before performing the heat recovery defrosting operation mode.
A heat medium temperature detection device is provided at any position of the flow path on the outlet side of the heat medium of the heat exchanger between heat mediums,
When the temperature of the heat medium detected by the heat medium temperature detection device is higher than a set temperature, the heat recovery defrosting operation mode is performed,
The air conditioner according to claim 1 or 2, wherein the bypass defrosting operation mode is performed when the temperature of the heat medium detected by the heat medium temperature detection device is lower than the set temperature.
A use-side air temperature detection device for detecting the temperature of air ventilated in the use-side heat exchanger;
The set temperature is
The air conditioning apparatus according to claim 3, wherein the air conditioning apparatus has a value equal to or higher than a temperature detected by the use-side air temperature detection apparatus.
The heating operation mode is:
The refrigerant flow switching device is switched to the heating side, the heat medium is heated by all the heat exchangers between the heat mediums, all the heat medium transport devices are operated, and all the use side heat exchangers are operated. A heating-only operation mode for sending out the warm heat medium,
The heat recovery defrosting operation mode is
During the heating only operation mode, the refrigerant flow switching device is switched to a cooling side so that the cold heat medium flows through all of the heat exchangers between heat mediums, and the heat source in all the heat exchangers between heat mediums Having a first heat recovery defrosting operation mode that absorbs heat held by the heat medium in the side refrigerant and melts frost formed around the heat source side heat exchanger;
When the defrosting is performed by switching from the heating only operation mode to the first heat recovery defrosting operation mode, the plurality of expansion devices are set to fully open in the first heat recovery defrosting operation mode. The air conditioning apparatus according to any one of 1 to 4.
The bypass defrosting operation mode is
There is a first bypass defrosting operation mode in which the refrigerant flow switching device is switched to the cooling side, and all the heat medium flows through the bypass pipe to melt frost formed around the heat source side heat exchanger. And
The air conditioner according to claim 5, wherein the defrosting is performed by switching from the first heat recovery defrosting operation mode to the first bypass defrosting.
The heating operation mode is:
Heating by switching the refrigerant flow switching device to the heating side, heating the heat medium in a part of the heat exchanger related to heat medium, and cooling the heat medium using the rest of the heat exchanger related to heat medium It has a main operation mode,
The heat recovery defrosting operation mode is
The refrigerant flow switching device is switched to the cooling side, the cold heat medium is caused to flow through all the heat exchangers between heat mediums, and the heat exchangers between heat mediums that are performing cooling in the heating main operation mode. For the heat exchanger related to heat medium that has been heated in the heating main operation mode while continuing cooling, the heat source side refrigerant absorbs heat held by the heat medium, and the heat source A second heat recovery defrosting operation mode for melting frost formed around the side heat exchanger;
When the defrosting is performed by switching from the heating main operation mode to the second heat recovery defrosting operation mode, the heating was performed in the heating main operation mode in the second heat recovery defrosting operation mode. The air conditioner according to any one of claims 1 to 4, wherein the expansion device corresponding to the heat exchanger related to heat medium is set to be fully open.
The bypass defrosting operation mode is
The refrigerant flow switching device is switched to the cooling side, the cold heat medium is caused to flow through a part of the heat exchanger related to heat medium, and the heat exchanger related to heat medium that has been cooled during the heating main operation The second bypass defrosting operation mode in which a part of the heat medium is allowed to flow through the bypass pipe and the frost formed around the heat source side heat exchanger is melted while continuing cooling.
The air conditioning apparatus according to claim 7, wherein the defrosting is performed by switching from the second heat recovery defrosting operation mode to the second bypass defrosting operation mode.
In the heat recovery defrosting operation mode,
Stop the blower that blows air to the use-side heat exchanger that had been performing the heating operation before entering the defrosting operation,
The air conditioner according to any one of claims 1 to 8, wherein a blower that blows air is operated to the use-side heat exchanger that is performing a cooling operation before entering a defrosting operation.
A plurality of indoor units for accommodating each of the plurality of use side heat exchangers;
At least one outdoor unit that houses the compressor and the heat source side heat exchanger;
And at least one relay unit that houses the plurality of heat exchangers between heat media, the plurality of expansion devices, the plurality of heat medium transfer devices, and the plurality of refrigerant flow switching devices,
The indoor unit, the outdoor unit, and the relay unit are:
The air conditioner according to any one of claims 1 to 9, wherein the air conditioner is configured to be formed separately from each other so that they can be installed at locations apart from each other.
During the bypass defrosting operation mode,
The air conditioning apparatus according to claim 1, wherein the heating operation is continued using the heat capacity of the heat medium that has been used in the heating operation until then.
When continuing the heating operation,
The air conditioner according to claim 11, wherein an air flow rate to the use-side heat exchanger that continues the heating operation is lower than a set air flow rate.
The air conditioning apparatus according to claim 12, wherein warm air can be supplied by a heating operation using the heat medium even when blowing air using outside air taken in for ventilation.