CN102112816A - Air conditioner - Google Patents

Abstract

The invention provides an air conditioner where labor required to select a system is reduced. The air conditioner (100) has at least one intermediate heat exchanger (15) for exchanging heat between a refrigerant and a heat medium; a refrigeration cycle circuit formed by interconnecting a compressor (10), a heat source-side heat exchanger (12), an expansion valve (16e), and a refrigerant-side flow path of the intermediate heat exchanger (15) via refrigerant piping (4) in which the refrigerant flows; and a heat medium circulation circuit formed by interconnecting a heat medium-side flow path of the intermediate heat exchanger (15), a pump (21), and a utilization-side heat exchanger (26) via piping (5) in which the heat medium flows. The compressor (10) and the heat source-side heat exchanger (12) are received in a heat source device (1), the intermediate heat exchanger (15) and the pump (21) are received in a relay unit (3), and the utilization-side heat exchanger (26) is received in an indoor unit (2). An expansion tank (6) for absorbing a change in the volume of the heat medium is connected to the heat medium circulation circuit.

Description

air conditioner

technical field

The present invention relates to an air conditioner suitable for multi-channel air conditioners used in buildings and the like.

Background technique

Conventionally, there is a multi-air conditioner for buildings (for example, refer to Patent Document 1) that applies an air conditioner that circulates a refrigerant between an outdoor unit that is a heat source unit disposed outdoors and an indoor unit disposed indoors. Cooling energy or heating energy is transmitted to air-conditioned areas such as indoors to perform cooling or heating operation. As the refrigerant used in this air conditioner, for example, HFC-based refrigerants are often used. In addition, in recent years, natural refrigerants such as carbon dioxide (CO ₂ ) have also been used.

In addition, there are also air-conditioning apparatuses of other structures typified by chiller systems. In this air conditioner, cold energy or heat energy is generated in a heat source unit arranged outdoors, and the cold energy or heat energy is transferred to a heat medium such as water or antifreeze by a heat exchanger arranged in the outdoor unit, and then transferred Cooling operation or heating operation is performed on indoor units arranged in the air-conditioning target area, that is, fan coil units, panel heaters, etc. (for example, refer to Patent Document 2). In addition, there is also a device that supplies cooling energy and heating energy by connecting four water pipes to a heat source machine, such as a waste heat recovery type refrigerator.

Patent Document 1: Japanese Patent Application Laid-Open No. 2-118372 (page 3, FIG. 1 )

Patent Document 2: Japanese Patent Laid-Open No. 2003-343936 (page 5, FIG. 1 )

Contents of the invention

The problem to be solved by the invention

In the conventional air-conditioning equipment, since the high-pressure refrigerant is sent to the indoor unit, the amount of refrigerant charge becomes very large. When the refrigerant leaks from the refrigerant circuit, for example, it will promote global warming and cause adverse effects on the global environment. Influence. In particular, R410A has a global warming coefficient as high as 1970. When using such a refrigerant, it is very important to reduce the amount of refrigerant charged from the viewpoint of protecting the global environment. In addition, when the refrigerant leaks into the living space, it may have adverse effects on the human body due to the chemical properties of the refrigerant. Therefore, measures such as ventilating more than necessary and installing a leak sensor must be performed, resulting in an increase in cost and power consumption.

The chiller system described in Patent Document 2 can solve these problems. However, since the heat exchange between the refrigerant and the water is performed in the outdoor unit and the water is transferred to the indoor unit, the water transfer power becomes very large, which increases energy consumption. In addition, when using water or the like to supply both the cooling energy and the heating energy, the number of connected pipes must be increased, and the effort, time, and cost of the installation process are increased.

In addition, in the system using water, since the density of water changes with the change of water temperature, it is necessary to have a device to absorb the expansion of water, and an expansion tank must be selected for each system installed. On the other hand, it also took a lot of thought. Usually, the expansion tank has a relatively large shape and cannot be accommodated in the ceiling or the like but must be installed in the machine room. That is, it is necessary to secure a large installation space in which the expansion tank can be installed.

The present invention was made to solve the above-mentioned problems, and its object is to provide an air-conditioning device that is highly energy-saving, does not send high-pressure refrigerant to the indoor unit, prevents the refrigerant from entering the living space, and is easy to perform and saves space. .

Technical solution to the problem

The air conditioner of the present invention has: at least one intermediate heat exchanger for exchanging heat between a refrigerant and a heat medium different from the above refrigerant; a refrigeration cycle circuit through which the refrigerant The circulating piping connects the compressor, the outdoor heat exchanger, at least one expansion valve, and the refrigerant-side passage of the intermediate heat exchanger; The flow path of the heat medium side of the heat exchanger, the pump, and the heat exchanger on the use side; the above-mentioned compressor and the above-mentioned outdoor heat exchanger are housed in the outdoor unit; the above-mentioned intermediate heat exchanger and the above-mentioned pump are housed in the relay unit; the above-mentioned use The side heat exchanger is accommodated in the indoor unit. An expansion absorption device for absorbing volume change of the heat medium is connected to the heat medium circulation circuit.

Invention effect

According to the air-conditioning apparatus of the present invention, it is not necessary to provide expansion absorbing means for each part, and the selection operation of the system can be simplified.

Description of drawings

FIG. 1 is a schematic diagram showing an example of an installed state of an air-conditioning apparatus according to Embodiment 1. FIG.

Fig. 2 is a schematic circuit diagram showing the configuration of the air-conditioning apparatus.

Fig. 3 is a partial circuit configuration diagram showing an example of a circuit configuration to which an expansion tank is connected.

Fig. 4 is a partial circuit configuration diagram showing another example of a circuit configuration to which an expansion tank is connected.

Fig. 5 is an internal perspective view showing a schematic structure of an expansion tank.

Fig. 6 is a graph showing the relationship between the water supply pressure and the capacity of the expansion tank.

7 is a refrigerant circuit diagram showing the flow of refrigerant during a cooling only operation mode of the air-conditioning apparatus.

Fig. 8 is a refrigerant circuit diagram showing the flow of refrigerant in a heating only operation mode of the air-conditioning apparatus.

Fig. 9 is a refrigerant circuit diagram showing the flow of refrigerant during a cooling main operation mode of the air-conditioning apparatus.

Fig. 10 is a refrigerant circuit diagram showing the flow of refrigerant during a heating main operation mode of the air-conditioning apparatus.

FIG. 11 is a circuit diagram showing a circuit configuration of an air-conditioning apparatus according to Embodiment 2. FIG.

Fig. 12 is a refrigerant circuit diagram showing the flow of refrigerant in a cooling only operation mode of the air-conditioning apparatus.

Fig. 13 is a refrigerant circuit diagram showing the flow of refrigerant in a heating only operation mode of the air-conditioning apparatus.

Fig. 14 is a refrigerant circuit diagram showing the flow of refrigerant in a cooling main operation mode of the air-conditioning apparatus.

Fig. 15 is a refrigerant circuit diagram showing the flow of refrigerant during a heating main operation mode of the air-conditioning apparatus.

Explanation of reference signs

1...heat source device (outdoor unit), 2...indoor unit, 2a...indoor unit, 2b...indoor unit, 2c...indoor unit, 2d...indoor unit, 3... Relay unit, 3a...Relay unit, 3b...Relay unit, 4...Refrigerant piping, 4a...1st connection pipe, 4b...2nd connection pipe, 5... Piping, 5a...piping, 5b...piping, 6...outdoor space, 7...living space, 9...building, 10...compressor, 11...four-way valve, 12...heat source side heat exchanger, 13a...check valve, 13b...check valve, 13c...check valve, 13d...check valve, 14...gas-liquid separator , 15...intermediate heat exchanger, 15a...the first intermediate heat exchanger, 15b...the second intermediate heat exchanger, 16...expansion valve, 16a...expansion valve, 16b... Expansion valve, 16c...expansion valve, 16d...expansion valve, 16e...expansion valve, 17...reservoir, 21...pump, 21a...1st pump, 21b...1st pump 2 pumps, 22... flow switching valve, 22a... flow switching valve, 22b... flow switching valve, 22c... flow switching valve, 22d... flow switching valve, 22e. ..Channel switching valve, 22f...Channel switching valve, 23...Channel switching valve, 23a...Channel switching valve, 23b...Channel switching valve, 23c...Channel switching Valve, 23d...flow path switching valve, 23e...flow path switching valve, 23f...flow path switching valve, 24...stop valve, 24a...stop valve, 24b...stop valve, 24c...globe valve, 24d...globe valve, 24e...globe valve, 24f...globe valve, 25...flow regulator, 25a...flow regulator, 25b...flow regulator Valve, 25c...flow regulating valve, 25d...flow regulating valve, 25e...flow regulating valve, 25f...flow regulating valve, 26...use side heat exchanger, 26a...use side Heat exchanger, 26b...use side heat exchanger, 26c...use side heat exchanger, 26d...use side heat exchanger, 26e...use side heat exchanger, 26f...use side Heat exchanger, 27...bypass, 27a...bypass, 27b...bypass, 27c...bypass, 27d...bypass, 27e...bypass, 27f... Bypass, 31...1st temperature sensor, 31a...1st temperature sensor, 31b...1st temperature sensor, 32...2nd temperature sensor, 32a...2nd temperature sensor, 32b. ..2nd temperature sensor, 33...3rd temperature sensor, 33a...3rd temperature sensor, 33b...3rd temperature sensor, 33c...3rd temperature sensor sensor, 34...4th temperature sensor, 34a...4th temperature sensor, 34b...4th temperature sensor, 34c...4th temperature sensor, 35...5th temperature sensor, 36. ..1st pressure sensor, 37...6th temperature sensor, 38...7th temperature sensor, 39...8th temperature sensor, 40...2nd pressure sensor, 42...heating side Expansion tank connection, 43...Cooling side expansion tank connection, 50...Non-residential space, 51...Pipe shaft, 60...Expansion tank, 60a...Heating side expansion tank, 60b Refrigeration Side expansion tank, 61...Expansion valve, 62...Water pipe, 65...Connecting pipe, 65a...Heating side connecting pipe, 65b...Cooling side connecting pipe, 66...Next door, 100 ...air conditioner, 101...outdoor unit, 102...indoor unit, 102a...indoor unit, 102b...indoor unit, 102c...indoor unit, 102d...indoor unit, 102e ...indoor unit, 102f...indoor unit, 103...relay unit, 104...three-way valve, 104a...three-way valve, 104b...three-way valve, 105...heat source Side heat exchanger, 106...expansion valve, 107...two-way valve, 107a...two-way valve, 107b...two-way valve, 107c...two-way valve, 108...refrigerant Piping, 108a...refrigerant piping, 108b...refrigerant piping, 108c...refrigerant piping, 110...compressor, 111...oil separator, 113...check valve, 200 ...air conditioning unit, 203...expansion valve, 203a...expansion valve, 203b...expansion valve, 204...two-way valve, 204a...two-way valve, 204b...two-way valve Valves, 205...two-way valve, 205a...two-way valve, 205b...two-way valve.

Detailed ways

Next, embodiments of the present invention will be described.

Embodiment 1

HFC-based refrigerants such as R410A, R407C, or R404A have a large global warming coefficient, and therefore, when the refrigerant leaks, the burden on the environment is large. For this reason, in recent years, natural refrigerants such as carbon dioxide, ammonia, or hydrocarbons, or refrigerants such as HFO have been considered as refrigerants replacing HFC-based refrigerants. However, these refrigerants are flammable (for example, ammonia, hydrocarbons), or the limit concentration of leakage is small. That is, although these refrigerants have a low global warming coefficient, they are not suitable for use in living spaces in view of their influence on the human body and safety.

Table 1 shows an example of the limit leakage concentration in the living space stipulated by the ISO standard.

Table 1

Refrigerant Limit concentration [kg/m ³ ] R410A 0.44 carbon dioxide 0.07 Ammonia 0.0004 propane 0.008

It can be seen from Table 1 that R410A, one of the HFC refrigerants widely used in direct expansion air conditioners, has a higher leakage limit concentration than other refrigerants, and the impact of leakage is not a problem. On the other hand, the leakage limit concentration of natural refrigerants such as ammonia, propane which is one of hydrocarbons, and carbon dioxide is very small. Therefore, in order to use these refrigerants in air conditioners, for example, it is necessary to take measures to shut off the refrigerant part in case of leakage. Countermeasures such as circuits and water circuits.

FIG. 1 is a schematic diagram illustrating an example of an installed state of an air-conditioning apparatus according to Embodiment 1 of the present invention. A schematic configuration of the air conditioning apparatus will be described with reference to FIG. 1 . This air conditioner performs a cooling operation or a heating operation using a refrigeration cycle (a refrigeration cycle circuit and a heat medium circulation circuit) in which a refrigerant (a heat source side refrigerant and a heat medium (water, antifreeze, etc.)) circulates. In addition, including FIG. 1, in the following drawings, the size relationship of each component may differ from the actual situation.

As shown in FIG. 1 , this air conditioner has one heat source device 1 as a heat source unit, a plurality of indoor units 2 , and a relay unit 3 interposed between the heat source device 1 and the indoor units 2 . The relay unit 3 performs heat exchange between the heat source side refrigerant and the heat medium, and has a first relay unit 3a and a second relay unit 3b. The heat source device 1 and the relay unit 3 are connected by the refrigerant pipe 4 that conducts the heat source side refrigerant, and the relay unit 3 and the indoor unit 2 are connected by the pipe 5 that conducts the heat medium, and the cooling energy generated in the heat source device 1 or Heat energy is distributed to indoor unit 2. In addition, the number of connected heat source devices 1, indoor units 2, and relay units 3 is not limited to the number shown in the figure.

The heat source device 1 is arranged in an outdoor space 6 outside the building 9 such as a building, and supplies cooling or heating energy to the indoor unit 2 through the relay unit 3 . The indoor unit 2 is arranged in a living space 7 such as a living room or a service room inside a building 9 that can transmit cooling air or heating air, and supplies cooling air or heating air to the living space that is an air-conditioning target area. 7. The relay unit 3 is formed separately from the heat source device 1 and the indoor unit 2, and is arranged in a position other than the outdoor space 6 and the living space 7 (hereinafter referred to as a non-residential space 50), and connects the heat source device 1 and the indoor unit 2, and connects the heat source device 1 and the indoor unit 2 to Cooling energy or thermal energy supplied from the heat source device 1 is transferred to the indoor unit 2 .

The outdoor space 6 refers to a place outside the building 9 , such as the roof shown in FIG. 1 . The non-residential space 50 refers to a place such as the upper part of the corridor where there are not always people, such as the ceiling of the common area, a common room with elevators, a mechanical room, a computer room, or a warehouse. In addition, the living space 7 refers to a place where there are always people, or a place where there are many people or a few people temporarily, such as offices, classrooms, conference rooms, cafeterias, service rooms, and the like. In addition, the shaded part shown in FIG. 1 has shown the piping shaft 51 for laying the piping 5. As shown in FIG.

The heat source device 1 and the first relay unit 3 a are connected by two refrigerant pipes 4 . The first relay unit 3 a and the second relay unit 3 b are connected by three refrigerant pipes 4 . Moreover, the 2nd relay unit 3b and each indoor unit 2 are connected by two pipes 5, respectively. In this way, the heat source device 1 and the relay unit 3 are connected by two refrigerant pipes 4, and the indoor unit 2 and the relay unit 3 are connected by two pipes 5, thereby facilitating construction of the air conditioner.

Like this, relay unit 3 is divided into 2 relay units, i.e. the 1st relay unit 3a and the 2nd relay unit 3b, can connect a plurality of the 2nd relay unit 3b to a 1st relay unit 3a (see figure 2). In addition, in Fig. 1, the indoor unit 2 is shown as an example of a ceiling box type, but it is not limited thereto, and can be of any type, as long as it can blow cold energy or heat energy to the living space 7 directly or through pipes, etc. For example, a ceiling-embedded type or a ceiling-suspended type may be used.

In addition, in FIG. 1, the case where the heat source apparatus 1 was installed in the outdoor space 6 was shown as an example, but it is not limited to this. For example, the heat source device 1 may also be installed in a surrounding space such as a machine room with a ventilation opening, or may be installed inside the building 9 if the waste heat can be discharged outside the building 9 through an exhaust duct, or, When the water-cooled heat source device 1 is used, it may be installed inside the building 9 . Even if the heat source device 1 is installed in such a place, no particular problem will occur.

FIG. 2 is a schematic circuit diagram showing the configuration of the air-conditioning apparatus 100 . A specific configuration of the air-conditioning apparatus 100 will be described with reference to FIG. 2 . As shown in FIG. 2, the heat source device 1 and the relay unit 3 are connected via the first intermediate heat exchanger 15a and the second intermediate heat exchanger 15b included in the second relay unit 3b, and the relay unit 3 and the indoor unit 2 are also connected. It is connected via the 1st intermediate heat exchanger 15a and the 2nd intermediate heat exchanger 15b which the 2nd relay unit 3 has. Next, the configuration and function of each component device provided in the air-conditioning apparatus 100 will be described.

[Heat source device 1]

The heat source device 1 accommodates a compressor 10 connected in series by a refrigerant pipe 4 , a four-way valve 11 as a refrigerant flow switching device, a heat source side heat exchanger (outdoor heat exchanger) 12 , and an accumulator 17 . Moreover, the heat source apparatus 1 is provided with the 1st connection piping 4a, the 2nd connection piping 4b, the check valve 13a, the check valve 13b, the check valve 13c, and the check valve 13d. By setting the first connection pipe 4a, the second connection pipe 4b, the check valve 13a, the check valve 13b, the check valve 13c, and the check valve 13d, no matter what operation the indoor unit 2 requires, the flow into the relay unit can be made. 3, the heat source side refrigerant flows in a certain direction.

The compressor 10 sucks the heat source side refrigerant, compresses the heat source side refrigerant to a high temperature and high pressure state, and may be constituted by, for example, a capacity-controllable inverter compressor or the like. The four-way valve 11 is used to switch the flow of the heat source side refrigerant during the heating operation and the flow of the heat source side refrigerant during the cooling operation. The heat source side heat exchanger 12 functions as an evaporator during the heating operation, and functions as a condenser during the cooling operation, between air supplied from a blower such as a fan (not shown in the figure) and the heat source side refrigerant. Heat exchange between the heat source side refrigerant evaporates gasification or condenses liquefaction. The accumulator 17 is provided on the suction side of the compressor 10 for storing excess refrigerant.

The check valve 13d is provided in the refrigerant pipe 4 between the relay unit 3 and the four-way valve 11, and allows the heat source side refrigerant to flow only in a predetermined direction (direction from the relay unit 3 to the heat source device 1). The check valve 13a is provided in the refrigerant pipe 4 between the heat source side heat exchanger 12 and the relay unit 3, and allows the heat source side refrigerant to flow only in a predetermined direction (direction from the heat source device 1 to the relay unit 3). The check valve 13b is provided in the first connecting pipe 4a, and allows only the flow of the heat source side refrigerant from the upstream side of the check valve 13d to the upstream side of the check valve 13a. The check valve 13 is provided in the second connecting pipe 4b, and allows only the flow of the heat source side refrigerant from the downstream side of the check valve 13d to the downstream side of the check valve 13a.

The first connecting pipe 4 a connects the refrigerant pipe 4 on the upstream side of the check valve 13 d and the refrigerant pipe 4 on the upstream side of the check valve 13 a in the heat source device 1 . The second connecting pipe 4 b connects the refrigerant pipe 4 on the downstream side of the check valve 13 d and the refrigerant pipe 4 on the downstream side of the check valve 13 a in the heat source device 1 . In addition, in FIG. 2 , the case where the first connecting pipe 4a, the second connecting pipe 4b, the check valve 13a, the check valve 13b, the check valve 13c, and the check valve 13d are provided as an example is shown, but the As a limitation, it is not necessary to set these components.

[Indoor unit 2]

A use-side heat exchanger 26 is mounted on each of the indoor units 2 . The use-side heat exchanger 26 is connected to the shutoff valve 24 and the flow rate regulating valve 25 of the second relay unit 3 b via the pipe 5 . The use-side heat exchanger 26 performs heat exchange between air supplied from a blower such as a fan (not shown) and a heat medium to generate heating air or cooling air to be supplied to an air-conditioning target area.

In this FIG. 2 , the case where four indoor units 2 are connected to the relay unit 3 is illustrated, and an indoor unit 2 a , an indoor unit 2 b , an indoor unit 2 c , and an indoor unit 2 d are shown from the bottom of the drawing. In addition, the use-side heat exchanger 26 corresponds to the indoor units 2a to 2d, and sequentially shows a use-side heat exchanger 26a, a use-side heat exchanger 26b, a use-side heat exchanger 26c, and a use-side heat exchanger from the bottom of the drawing. switch 26d. In addition, similarly to FIG. 1 , the number of connected indoor units 2 is not limited to four as shown in FIG. 2 .

[Relay unit 3]

The relay unit 3 is composed of sub-frames of the first relay unit 3a and the second relay unit 3b. By employing such a structure, a plurality of second relay units 3b can be connected to one first relay unit 3a. In the first relay unit 3a, a gas-liquid separator 14 and an expansion valve 16e are provided. In the second relay unit 3b, two intermediate heat exchangers 15, four expansion valves 16, two pumps 21, four flow path switching valves 22, four flow path switching valves 23, and four stop valves 24 are provided. And 4 flow regulating valves 25.

Gas-liquid separator 14, one refrigerant pipe 4 connected to heat source device 1, and two refrigerant pipes 4 connected to first intermediate heat exchanger 15a and second intermediate heat exchanger 15b of second relay unit 3b connected to separate the heat source side refrigerant supplied from the heat source device 1 into a vapor refrigerant and a liquid refrigerant. The expansion valve 16e is provided between the refrigerant pipe 4 connecting the expansion valve 16a and the expansion valve 16b and the gas-liquid separator 14, and functions as a pressure reducing valve and a throttling device to decompress and expand the heat source side refrigerant. The expansion valve 16e can be constituted by, for example, an electronic expansion valve whose opening degree can be variably controlled.

The two intermediate heat exchangers 15 (the first intermediate heat exchanger 15a and the second intermediate heat exchanger 15b) function as condensers or evaporators, and the refrigerant and the heat medium exchange heat on the heat source side. The cooling or heating energy generated by 1 is supplied to the indoor unit 2. In the flow of the heat source side refrigerant, the first intermediate heat exchanger 15a is provided between the gas-liquid separator 14 and the expansion valve 16d. In the flow of the heat source side refrigerant, the second intermediate heat exchanger 15b is provided between the expansion valve 16a and the expansion valve 16c.

The four expansion valves 16 (expansion valves 16a to 16d) function as pressure reducing valves and throttling devices, and decompress and expand the heat source side refrigerant. The expansion valve 16a is provided between the expansion valve 16b and the second intermediate heat exchanger 15b. The expansion valve 16b is provided in parallel with the expansion valve 16a. The expansion valve 16c is provided between the second intermediate heat exchanger 15b and the first relay unit 3a. The expansion valve 16d is provided between the first intermediate heat exchanger 15a, the expansion valve 16a, and the expansion valve 16b. The four expansion valves 16 may be composed of, for example, electronic expansion valves whose openings can be variably controlled.

The two pumps 21 (the first pump 21 a and the second pump 21 b ) are composed of pumps and the like, and circulate the heat medium in the conduction pipe 5 . The first pump 21 a is provided in the piping 5 between the first intermediate heat exchanger 15 a and the flow path switching valve 22 . The second pump 21 b is provided in the piping 5 between the second intermediate heat exchanger 15 b and the flow path switching valve 22 . The types of the first pump 21a and the second pump 21b are not particularly limited, and may be constituted by, for example, capacity-controllable pumps or the like.

The four flow path switching valves 22 (flow path switching valves 22 a to 22 d ) are composed of three-way valves, and are used to switch the flow path of the heat medium. The flow path switching valves 22 are provided in a number corresponding to the installed number of the indoor units 2 (here, four). The flow path switching valve 22 is provided on the inlet side of the heat medium flow path of the use side heat exchanger 26, and one of its three-way is connected to the first intermediate heat exchanger 15a, one is connected to the second intermediate heat exchanger 15b, and the other is connected to the second intermediate heat exchanger 15b. Connected to the shut-off valve 24. In addition, corresponding to the indoor unit 2, a flow path switching valve 22a, a flow path switching valve 22b, a flow path switching valve 22c, and a flow path switching valve 22d are shown in order from the bottom of the drawing.

The four flow path switching valves 23 (flow path switching valves 23 a to 23 d ) are composed of three-way valves, and are used to switch the flow path of the heat medium. The flow path switching valves 23 are provided in a number corresponding to the installed number of indoor units 2 (here, four). The flow path switching valve 23 is provided on the outlet side of the heat medium flow path of the use-side heat exchanger 26, and one of its three-way connections is connected to the first intermediate heat exchanger 15a, one is connected to the second intermediate heat exchanger 15b, and the other is connected to the second intermediate heat exchanger 15b. It is connected with the flow regulating valve 25. In addition, corresponding to the indoor unit 2, a flow path switching valve 23a, a flow path switching valve 23b, a flow path switching valve 23c, and a flow path switching valve 23d are shown in order from the bottom of the drawing.

The four stop valves 24 (stop valves 24 a to 24 d ) are composed of two-way valves and are used to open and close the piping 5 . The shutoff valves 24 are provided in a number corresponding to the number of indoor units 2 (here, four). The stop valve 24 is provided on the inlet side of the heat medium flow path of the use-side heat exchanger 26 , and one of its two ports is connected to the use-side heat exchanger 26 , and the other is connected to the flow path switching valve 22 . In addition, corresponding to the indoor unit 2, a shutoff valve 24a, a shutoff valve 24b, a shutoff valve 24c, and a shutoff valve 24d are shown in order from the bottom of the drawing.

The four flow regulating valves 25 (flow regulating valves 25 a to 25 d ) are composed of three-way valves and are used to switch the flow path of the heat medium. The flow path switching valves 25 are provided in a number corresponding to the installed number of the indoor units 2 (here, four). The flow regulating valve 25 is arranged on the outlet side of the heat medium flow path of the use-side heat exchanger 26, and one of its three-way is connected to the use-side heat exchanger 26, one is connected to the bypass 27, and the other is connected to the flow path switching valve 23. connect. In addition, corresponding to the indoor unit 2, the flow rate adjustment valve 25a, the flow rate control valve 25b, the flow rate control valve 25c, and the flow rate control valve 25d are shown in order from the bottom of the figure.

The bypass 27 connects the pipe 5 between the shutoff valve 24 and the use-side heat exchanger 26 and the flow regulating valve 25 . The number of bypasses 27 corresponds to the number of indoor units 2 installed (here, four, namely, bypass 27a, bypass 27b, bypass 27c, and bypass 27d). In addition, corresponding to the indoor unit 2, a bypass 27a, a bypass 27b, a bypass 27c, and a bypass 27d are shown in order from the bottom of the drawing.

In addition, two first temperature sensors 31, two second temperature sensors 32, four third temperature sensors 33, four fourth temperature sensors 34, a fifth temperature sensor 35, and a second relay unit 3b are provided in the second relay unit 3b. 1 pressure sensor 36, sixth temperature sensor 37 and seventh temperature sensor 38. The information detected by these detection means is sent to a control device (not shown) that controls the operation of the air-conditioning apparatus 100, and is used to control the driving frequency of the compressor 10 and the pump 21, and to switch the flow path of the heat medium flowing through the piping 5. wait.

Two first temperature sensors 31 (the first temperature sensor 31a and the first temperature sensor 31b) are used to detect the heat medium flowing out from the intermediate heat exchanger 15, that is, the temperature of the heat medium at the outlet of the intermediate heat exchanger 15, for example, by Thermistor etc. The first temperature sensor 31a is provided in the pipe 5 on the inlet side of the first pump 21a. The second temperature sensor 31b is provided in the piping 5 on the inlet side of the second pump 21b.

Two second temperature sensors 32 (the second temperature sensor 32a and the second temperature sensor 32b) are used to detect the heat medium flowing into the intermediate heat exchanger 15, that is, the temperature of the heat medium at the entrance of the intermediate heat exchanger 15, for example, it can be detected by heat Sensitive resistance and so on. The second temperature sensor 32a is provided in the pipe 5 on the inlet side of the first intermediate heat exchanger 15a. The second temperature sensor 32b is provided in the pipe 5 on the inlet side of the second intermediate heat exchanger 15b.

Four third temperature sensors 33 (third temperature sensors 33a to 33d) are arranged on the inlet side of the heat medium flow path of the use-side heat exchanger 26, and are used to detect the temperature of the heat medium flowing into the use-side heat exchanger 26, which can be determined by Thermistor etc. The third temperature sensors 33 are provided in a number corresponding to the installed number of indoor units 2 (here, four). In addition, corresponding to the indoor unit 2, a third temperature sensor 33a, a third temperature sensor 33b, a third temperature sensor 33c, and a third temperature sensor 33d are shown in order from the bottom of the drawing.

Four fourth temperature sensors 34 (fourth temperature sensors 34a to 34d) are provided on the outlet side of the heat medium flow path of the use-side heat exchanger 26 to detect the temperature of the heat medium flowing out of the use-side heat exchanger 26, It can be composed of a thermistor or the like. The fourth temperature sensors 34 are provided in a number corresponding to the installed number of indoor units 2 (here, four). In addition, corresponding to the indoor unit 2, a fourth temperature sensor 34a, a fourth temperature sensor 34b, a fourth temperature sensor 34c, and a fourth temperature sensor 34d are shown in order from the bottom of the drawing.

The fifth temperature sensor 35 is arranged on the outlet side of the heat source side refrigerant flow path of the first intermediate heat exchanger 15a, and is used to detect the temperature of the heat source side refrigerant flowing out of the first intermediate heat exchanger 15a, which can be controlled by a thermistor or the like. constitute. The first pressure sensor 36 is provided on the outlet side of the heat source side refrigerant passage of the first intermediate heat exchanger 15a, and detects the pressure of the heat source side refrigerant flowing out of the first intermediate heat exchanger 15a.

The sixth temperature sensor 37 is provided on the inlet side of the heat source side refrigerant flow path of the second intermediate heat exchanger 15b, and is used to detect the temperature of the heat source side refrigerant flowing into the second intermediate heat exchanger 15b, and may be formed of a thermistor or the like. . The seventh temperature sensor 38 is arranged on the outlet side of the heat source side refrigerant flow path of the second intermediate heat exchanger 15b, and is used to detect the temperature of the heat source side refrigerant flowing out from the second intermediate heat exchanger 15b, which can be controlled by a thermistor or the like. constitute.

The piping 5 through which the heat medium is conducted is composed of a piping connected to the first intermediate heat exchanger 15a (hereinafter referred to as piping 5a) and a piping connected to the second intermediate heat exchanger 15b (hereinafter referred to as piping 5b). The piping 5a and the piping 5b are branched for each indoor unit 2 connected to the relay unit 3 (here, each is divided into four branches). The pipe 5 a and the pipe 5 b are connected by a flow path switching valve 22 , a flow path switching valve 23 , and a flow rate regulating valve 25 . By controlling the channel switching valve 22 and the channel switching valve 23 , it is determined whether the heat medium in the transfer pipe 5 a flows into the use-side heat exchanger 26 or the heat medium in the transfer pipe 5 b flows into the use-side heat exchanger 26 .

In this air-conditioning apparatus 100, a compressor 10, a four-way valve 11, a heat source side heat exchanger 12, a first intermediate heat exchanger 15a, and a second intermediate heat exchanger 15b are sequentially connected in series through refrigerant piping 4 to constitute Refrigeration cycle. In addition, the first intermediate heat exchanger 15a, the first pump 21a, and the use-side heat exchanger 26 are sequentially connected in series through the piping 5a to constitute a heat medium circulation circuit. Similarly, the second intermediate heat exchanger 15b, the second pump 21b, and the use-side heat exchanger 26 are sequentially connected in series through the pipe 5b to constitute a heat medium circulation circuit. That is, a plurality of use-side heat exchangers 26 are connected in parallel to each intermediate heat exchanger 15 to form a plurality of heat medium circulation circuits.

That is, in the air conditioner 100 , the heat source device 1 and the relay unit 3 are connected via the first intermediate heat exchanger 15 a and the second intermediate heat exchanger 15 b provided in the relay unit 3 . The relay unit 3 and the indoor unit 2 are connected by the first intermediate heat exchanger 15a and the second intermediate heat exchanger 15b, and the heat source side refrigerant as the primary side refrigerant circulating in the refrigeration cycle and the heat source side refrigerant as the primary side refrigerant circulating in the heat medium circulation circuit The heat medium of the secondary-side refrigerant in the intermediate cycle exchanges heat in the first intermediate heat exchanger 15a and the second intermediate heat exchanger 15b.

Here, the types of refrigerants used in the refrigeration cycle and the heat medium cycle will be described.

In the refrigeration cycle, for example, a non-azeotropic mixed refrigerant such as R407C, a quasi-azeotropic mixed refrigerant such as R410A, or a single refrigerant such as R22 can be used. In addition, natural refrigerants such as carbon dioxide and hydrocarbons can also be used. By using natural refrigerant as the heat source side refrigerant, the global warming effect caused by refrigerant leakage can be suppressed. In particular, carbon dioxide, since its high-pressure side performs heat exchange without condensation in a supercritical state, so, as shown in FIG. When the heat medium is in the form of counterflow, the heat exchange performance when heating the heat medium can be improved.

The heat medium circulation circuit is connected to the use-side heat exchanger 26 of the indoor unit 2 as described above. Therefore, in the air-conditioning apparatus 100, it is assumed that a highly safe heat medium is used in consideration of leakage of the heat medium into the room where the indoor unit 2 is installed. Therefore, as the heat medium, for example, water, antifreeze, a mixture of water and antifreeze, or the like can be used. According to this configuration, even at low outdoor air temperature, refrigerant leakage due to freezing and corrosion can be prevented, and high reliability can be obtained. In addition, when the indoor unit 2 is installed in a place where moisture should be avoided, such as a computer room, a fluorine-based inert liquid having high thermal insulation properties may be used as a heat medium.

FIG. 3 is a partial circuit configuration diagram showing an example of a circuit configuration to which an expansion tank 60 is connected. FIG. 4 is a partial circuit configuration diagram showing another example of the circuit configuration to which the expansion tank 60 is connected. FIG. 5 is an internal perspective view showing a schematic structure of the expansion tank 60 . FIG. 6 is a graph showing the relationship between the water supply pressure and capacity of the expansion tank 60 . Referring to FIGS. 3 to 6 , the expansion tank 60 will be described together with installation restrictions of the relay unit 3 . As shown in FIG. 3 or FIG. 4 , in the air-conditioning apparatus 100 , an expansion tank 60 , which is one of expansion absorbers for absorbing a volume change of the heat medium, is connected to the second relay unit 3 b. In addition, the case where the expansion tank 60 is housed in the relay unit 3 will be described as an example. In FIG. 6 , the horizontal axis represents the water supply pressure of city water [MPaG], and the vertical axis represents the capacity [L] of the expansion tank 60 .

A heat medium such as water has a characteristic of increasing in volume when the temperature rises and decreasing in volume when the temperature falls. Therefore, when the flow path of the heat medium is a closed circuit like the air-conditioning apparatus 100 of Embodiment 1, if there is no mechanism for absorbing the volume change, the pipe 5 may rupture due to volume expansion. For this reason, in the air-conditioning apparatus 100, two expansion tanks 60 are provided as devices for absorbing the expansion of the heat medium. The two expansion tanks 60 (the heating side expansion tank 60a and the cooling side expansion tank 60b) are connected by connecting pipes. 65 (heating-side connecting pipe 65 a and cooling-side connecting pipe 65 b ) are respectively connected to the heating-side expansion tank connection port 42 and the cooling-side expansion tank connection port 43 shown in FIG. 2 .

The heating-side expansion tank 60a and the cooling-side expansion tank 60b have a partition wall 66 made of flexible rubber or the like inside, and an air pool is formed in the lower part with the partition wall 66 as a boundary, and the heat medium flows into the upper part. That is, the heating-side connecting pipe 65a is connected to the upper part of the heating-side expansion tank 60a, and the cooling-side connecting pipe 65b is connected to the upper part of the cooling-side expansion tank 60b. When the temperature of the heat medium is low, the partition wall 66 is located at the top, and when the temperature of the heat medium rises and the volume of the heat medium increases, the partition wall 66 bulges downward to absorb volume expansion.

Next, the capacity of the expansion tank 60 will be described.

Assuming that the pressure of the air storage part before the heat medium expands is P0, and the volume of the air storage part is V0, after the heat medium expands, the pressure of the air storage part reaches the limit pressure P1 of the expansion tank 60, the volume of the air storage part decreases, and the air The volume of the storage part becomes V1. Then, according to the Boyle-Charlie law, the following equation (1) holds.

(1) P0*V0=P1*V1

V1＝P0＊V0/P1

Assuming that the expansion amount of the heat medium is Ve, the following formula (2) is established.

(2) Ve=V0-V1=V0-P0*V0/P1=V0*(1-P0/P1)

Therefore, when the required volume of the air storage part is expressed by the expansion amount and pressure of the heat medium, it is expressed by the following formula (3).

(3) V0=Ve/(1-P0/P1)

It can be seen from formula (3) that in order to reduce the volume of the expansion tank 60, P0/P1 must be reduced.

That is, as a specific means for reducing the volume of the expansion tank 60 , means for lowering the minimum pressure of the air storage part, increasing the pressure resistance of the expansion tank 60 , and the like can be considered. In particular, considering the installation situation of the relay unit 3, since the relay unit 3 is often installed in the ceiling, etc., there is a restriction that the height of the relay unit 3 must be kept below 300 mm. Based on such a background, downsizing of the expansion tank 60 is required, that is, reduction of P0/P1 is required.

In order to increase P0 (increase the pressure resistance), it is necessary to increase the wall thickness of the container of the expansion tank 60, which makes the expansion tank 60 heavy and difficult to store in the ceiling. In addition, in order to reduce P1 (decrease the initial pressure), it is necessary to restrict the water supply pressure and restrict the positions of the relay unit 3 and the indoor unit 2 . It can be seen from Fig. 6 that the volume of the expansion tank 60 varies greatly due to the difference of the minimum pressure. That is, as can be seen from FIG. 6 , in order to suppress the volume of the expansion tank 60 to about 5 liters or less, it is necessary to set the minimum pressure to about 100 kPaG.

In addition, in order to prevent the pressure heads of the first pump 21a and the second pump 21b from acting on the expansion tank 60, the connection ports connected to the expansion tank 60 (the heat supply side expansion tank connection port 42 and the cooling side expansion tank connection port 43 ), as shown in Figure 2, must be taken out from the suction side of the first pump 21a and the second pump 21b. In addition, here, the case where the ultimate pressure of the expansion tank 60 is 490 kPaG is demonstrated.

As shown in Fig. 3, when the relay unit 3 is arranged above the indoor unit 2, since there is no pressure head acting on the expansion tank 60, P0 is infinitely close to 0, so the expansion tank 60 can be miniaturized. However, in reality, the relay unit 3 is not necessarily installed above the indoor unit 2 . That is, it is conceivable to install the relay unit 3 and the indoor unit 2 as shown in FIG. 4 . In addition, the water pipe 62 is connected to the heat medium circulation circuit of the air-conditioning apparatus 100 via the expansion valve 61 , and water is injected into the heat medium circulation circuit by the pressure of the water in the water pipe.

That is, in the installation situation shown in FIG. 4 , the pressure of the water pipe water supplied from the water pipe 62 acts on the expansion tank 60 . Therefore, as shown in Figure 4, when the height difference h between the indoor unit 2 and the relay unit 3 is 10m, and the water supply pressure of the water pipe is about 100kPaG, it can be seen from Figure 6 that the volume of the expansion tank 60 can be suppressed to 5 liters Left and right, therefore, it can be made into a size that can be stored in the ceiling. In this way, since the expansion tank 60 is preliminarily provided in the air-conditioning apparatus 100, it is not necessary to install the expansion tank 60 for each component as in the past, and the selection operation of the system can be simplified. In addition, when the expansion tank 60 is not accommodated in the relay unit 3, the height difference h between the indoor unit 2 and the expansion tank 60 is 10 m.

Here, each operation mode performed by the air-conditioning apparatus 100 will be described.

This air-conditioning apparatus 100 can perform cooling operation or heating operation in the indoor unit 2 according to an instruction from each indoor unit 2 . That is, the air-conditioning apparatus 100 may perform the same operation by all the indoor units 2, or may perform different operations by each indoor unit 2. Next, the four operation modes performed by the air-conditioning apparatus 100, that is, the cooling only operation mode in which all driven indoor units 2 perform cooling operation, the heating only operation mode in which all driven indoor units 2 perform heating operation, and the cooling load Flow of the refrigerant in the main cooling operation mode with a large heating load and the main heating operation mode with a large heating load.

[Full cooling operation mode]

FIG. 7 is a refrigerant circuit diagram showing the flow of refrigerant in the cooling only operation mode of the air-conditioning apparatus 100 . In FIG. 7 , the cooling only operation mode will be described by taking a case where cooling loads are generated only in the use-side heat exchanger 26 a and the use-side heat exchanger 26 b as an example. That is, in FIG. 7, the case where the cooling load does not generate|occur|produce in the use-side heat exchanger 26c and the use-side heat exchanger 26d is shown. In addition, in FIG. 7 , piping indicated by bold lines is piping through which refrigerant (heat source side refrigerant and heat medium) circulates. In addition, 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 dotted line arrow.

In the cooling only operation mode shown in FIG. 7 , in the heat source device 1 , the four-way valve 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 3, the first pump 21a is stopped, the second pump 21b is driven, the shutoff valve 24a and the shutoff valve 24b are opened, the shutoff valve 24c and the shutoff valve 24d are closed, and the heat medium is used between the second intermediate heat exchanger 15b and each It circulates between the side heat exchangers 26 (use-side heat exchanger 26a and use-side heat exchanger 26b). In this state, the operation of the compressor 10 is started.

First, the flow of the heat source side refrigerant in the refrigeration cycle will be described.

The low-temperature, low-pressure refrigerant is compressed by the compressor 10 to become a high-temperature, high-pressure gas refrigerant, and then discharged. The high-temperature, high-pressure gas refrigerant discharged from the compressor 10 flows into the heat source side heat exchanger 12 through the four-way valve 11 . Then, in the heat source side heat exchanger 12 , it is condensed and liquefied while dissipating heat to the outdoor air to become a high-pressure liquid refrigerant. The high-pressure liquid refrigerant flowing out of the heat source side heat exchanger 12 flows out of the heat source device 1 through the check valve 13 a, and flows into the first relay unit 3 a through the refrigerant pipe 4 . The high-pressure liquid refrigerant that has flowed into the first relay unit 3a flows into the gas-liquid separator 14, and then flows into the second relay unit 3b through the expansion valve 16e.

The refrigerant flowing into the second relay unit 3b is throttled and expanded by the expansion valve 16a, and becomes a low-temperature, low-pressure gas-liquid two-phase refrigerant. This gas-liquid two-phase refrigerant flows into the second intermediate heat exchanger 15b functioning as an evaporator, absorbs heat from the heat medium circulating in the heat medium circulation circuit, and turns into a low-temperature, low-pressure gas while cooling the heat medium. Refrigerant. The gas refrigerant flowing out of the second intermediate heat exchanger 15b passes through the expansion valve 16c, flows out from the second relay unit 3b and the first relay unit 3a, and flows into the heat source device 1 through the refrigerant pipe 4. The refrigerant that has flowed into the heat source device 1 passes through the check valve 13d, passes through the four-way valve 11 and the accumulator 17, and is sucked into the compressor 10 again. In addition, the expansion valve 16b and the expansion valve 16d have a small opening so that the refrigerant does not flow, and the expansion valve 16c is fully open so that no pressure loss occurs.

Next, the flow of the heat medium in the heat medium circulation circuit will be described.

In the cooling only operation mode, since the first pump 21a is stopped, the heat medium circulates through the piping 5b. The heat medium cooled by the heat source side refrigerant in the second intermediate heat exchanger 15b flows through the pipe 5b by the second pump 21b. The heat medium that is pressurized and flowed out by the second pump 21b passes through the flow path switching valve 22 (the flow path switching valve 22a and the flow path switching valve 22b) and passes through the shutoff valve 24 (the shutoff valve 24a and the shutoff valve 24b) to flow in for use. The side heat exchanger 26 (the use side heat exchanger 26a and the use side heat exchanger 26b). Then, the use-side heat exchanger 26 absorbs heat from the indoor air, and cools an air-conditioned area such as a room where the indoor unit 2 is installed.

Then, the heat medium flowing out from the use-side heat exchanger 26 flows into the flow rate regulating valve 25 (the flow rate regulating valve 25 a and the flow rate regulating valve 25 b ). At this time, with the help of the flow regulating valve 25, only the heat medium of the flow rate required to supply the air-conditioning load required by the air-conditioning target area such as indoors flows into the use-side heat exchanger 26, and the rest of the heat medium passes through the bypass 27 (bypass) The path 27 a and the bypass path 27 b ) flow by bypassing the use-side heat exchanger 26 .

The heat medium passing through the bypass 27 does not participate in heat exchange, but merges with the heat medium passing through the use-side heat exchanger 26, passes through the flow path switching valve 23 (flow path switching valve 23a and flow path switching valve 23b), and flows into the second middle The heat exchanger 15b is then sucked into the second pump 21b. In addition, by controlling and maintaining the temperature difference between the third temperature sensor 33 and the fourth temperature sensor 34 at a target value, the air-conditioning load required for an air-conditioning target area such as a room can be supplied.

At this time, since it is not necessary to flow the heat medium into the use-side heat exchanger 26 with no heat load (including heat stop), the flow path is closed with the stop valve 24 so that the heat medium does not flow into the use-side heat exchanger 26 . In Fig. 7, in the use-side heat exchanger 26a and the use-side heat exchanger 26b, since there is a heat load, the heat medium flows through, and in the use-side heat exchanger 26c and the use-side heat exchanger 26d , there is no heat load, and the corresponding shut-off valve 24c and shut-off valve 24d are set to the closed state. When a cooling load is generated from the use-side heat exchanger 26c or the use-side heat exchanger 26d, the shutoff valve 24c or the shutoff valve 24d may be opened to circulate the heat medium.

[Full heating operation mode]

FIG. 8 is a refrigerant circuit diagram showing the refrigerant flow in the heating only operation mode of the air-conditioning apparatus 100 . In this FIG. 8 , the heating only operation mode will be described by taking as an example a case where a thermal load is generated only in the use-side heat exchanger 26 a and the use-side heat exchanger 26 b. That is, in FIG. 8, the case where thermal load does not generate|occur|produce in the use side heat exchanger 26c and the use side heat exchanger 26d is shown. In addition, in FIG. 8 , pipes indicated by thick lines are pipes through which refrigerant (heat source side refrigerant and heat medium) circulates. In addition, 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 dotted line arrow.

In the heating only operation mode shown in FIG. 8 , in the heat source device 1 , the four-way valve 11 is switched so that the heat source side refrigerant discharged from the compressor 10 flows into the relay unit 3 without passing through the heat source side heat exchanger 12 . . In the relay unit 3, the first pump 21a is driven, the second pump 21b is stopped, the shutoff valve 24a and the shutoff valve 24b are opened, the shutoff valve 24c and the shutoff valve 24d are closed, and the heat medium is used in the first intermediate heat exchanger 15a and each Between the side heat exchangers 26 (use-side heat exchanger 26a and use-side heat exchanger 26b ), switching is performed cyclically. In this state, the operation of the compressor 10 is started.

First, the flow of the heat source side refrigerant in the refrigeration cycle will be described.

The low-temperature, low-pressure refrigerant is compressed by the compressor 10 to become a high-temperature, high-pressure gas refrigerant, and then discharged. The high-temperature, high-pressure gas refrigerant discharged from the compressor 10 passes through the four-way valve 11, flows through the first connecting pipe 4a, and flows out of the heat source device 1 through the check valve 13b. The high-temperature, high-pressure gas refrigerant flowing out of the heat source device 1 flows into the first relay unit 3 a through the refrigerant pipe 4 . The high-temperature, high-pressure gas refrigerant that has flowed into the first relay unit 3a flows into the gas-liquid separator 14, and then flows into the first intermediate heat exchanger 15a after passing through the expansion valve 16e. The high-temperature, high-pressure gas refrigerant flowing into the first intermediate heat exchanger 15a is condensed and liquefied while dissipating heat to the heat medium circulating in the heat medium circuit to become a high-pressure liquid refrigerant.

The high-pressure liquid refrigerant flowing out of the first intermediate heat exchanger 15a is throttled and expanded by the expansion valve 16d, and becomes a low-temperature, low-pressure gas-liquid two-phase state. The gas-liquid two-phase refrigerant throttled by the expansion valve 16 d passes through the expansion valve 16 b , flows through the refrigerant piping 4 , and then flows into the heat source device 1 . The refrigerant flowing into the heat source device 1 passes through the check valve 13d, passes through the second connecting pipe 4b, and flows into the heat source side heat exchanger 12 functioning as an evaporator. Then, the refrigerant flowing into the heat source side heat exchanger 12 absorbs heat from the outdoor air in the heat source side heat exchanger 12 to become a low-temperature, low-pressure gas refrigerant. The low-temperature, low-pressure gas refrigerant flowing out of the heat source side heat exchanger 12 returns to the compressor 10 through the four-way valve 11 and the accumulator 17 . In addition, the expansion valve 16a, the expansion valve 16c, and the expansion valve 16e have a small opening so that the refrigerant does not flow.

Next, the flow of the heat medium in the heat medium circulation circuit will be described.

In the heating only operation mode, since the second pump 21b is stopped, the heat medium circulates through the piping 5b. The heat medium heated by the heat source side refrigerant in the first intermediate heat exchanger 15a flows through the pipe 5a by the first pump 21a. The heat medium that is pressurized and flowed out by the first pump 21a passes through the flow path switching valve 22 (the flow path switching valve 22a and the flow path switching valve 22b) and passes through the shutoff valve 24 (the shutoff valve 24a and the shutoff valve 24b) to flow in for use. The side heat exchanger 26 (the use side heat exchanger 26a and the use side heat exchanger 26b). Then, in the use-side heat exchanger 26, heat is supplied to the indoor air, and heat is supplied to an air-conditioning target area such as a room where the indoor unit 2 is installed.

Then, the heat medium flowing out from the use-side heat exchanger 26 flows into the flow rate regulating valve 25 (the flow rate regulating valve 25 a and the flow rate regulating valve 25 b ). At this time, with the help of the flow regulating valve 25, only the heat medium of the flow rate required to supply the air-conditioning load required by the air-conditioning target area such as indoors flows into the use-side heat exchanger 26, and the rest of the heat medium passes through the bypass 27 (bypass) The path 27 a and the bypass path 27 b ) flow by bypassing the use-side heat exchanger 26 .

The heat medium passing through the bypass 27 does not participate in heat exchange, but merges with the heat medium passing through the use-side heat exchanger 26, passes through the flow path switching valve 23 (flow path switching valve 23a and flow path switching valve 23b), and flows into the first middle The heat exchanger 15a is then sucked into the first pump 21a. In addition, by controlling and maintaining the temperature difference between the third temperature sensor 33 and the fourth temperature sensor 34 at a target value, the air-conditioning load required for an air-conditioning target area such as a room can be supplied.

At this time, since it is not necessary to flow the heat medium into the use-side heat exchanger 26 with no heat load (including heat stop), the flow path is closed with the stop valve 24 so that the heat medium does not flow into the use-side heat exchanger 26 . In Fig. 8, in the use-side heat exchanger 26a and the use-side heat exchanger 26b, since there is a heat load, the heat medium flows through, and in the use-side heat exchanger 26c and the use-side heat exchanger 26d , there is no heat load, and the corresponding shut-off valve 24c and shut-off valve 24d are set to the closed state. When a heat load is generated from the use-side heat exchanger 26c or the use-side heat exchanger 26d, the shutoff valve 24c or the shutoff valve 24d is opened to circulate the heat medium.

[Main cooling operation mode]

FIG. 9 is a refrigerant circuit diagram showing the flow of the refrigerant during the cooling main operation mode of the air-conditioning apparatus 100 . In FIG. 9 , the main cooling operation mode will be described by taking, as an example, a case where a heating load is generated in the use-side heat exchanger 26a and a cooling load is generated in the use-side heat exchanger 26b. That is, in FIG. 9, the case where neither a heating load nor a cooling load occurs in the use side heat exchanger 26c and the use side heat exchanger 26d is shown. In addition, in FIG. 9 , pipes indicated by thick lines are pipes through which refrigerant (heat source side refrigerant and heat medium) circulates. In addition, 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 dotted line arrow.

In the cooling main operation mode shown in FIG. 9 , in the heat source device 1 , the four-way valve 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 3, the first pump 21a and the second pump 21b are driven, the shutoff valve 24a and the shutoff valve 24b are opened, the shutoff valve 24c and the shutoff valve 24d are closed, and the heat medium is heated between the first intermediate heat exchanger 15a and the use side. It circulates between the exchangers 26a, and between the second intermediate heat exchanger 15b and the use-side heat exchanger 26b. In this state, the operation of the compressor 10 is started.

First, the flow of the heat source side refrigerant in the refrigeration cycle will be described.

The low-temperature, low-pressure refrigerant is compressed by the compressor 10 to become a high-temperature, high-pressure gas refrigerant, and then discharged. The high-temperature, high-pressure gas refrigerant discharged from the compressor 10 flows into the heat source side heat exchanger 12 through the four-way valve 11 . Then, in the heat source side heat exchanger 12 , it condenses while dissipating heat to the outdoor air to become a gas-liquid two-phase refrigerant. The gas-liquid two-phase refrigerant flowing out of the heat source side heat exchanger 12 flows out of the heat source device 1 through the check valve 13 a, and flows into the first relay unit 3 a through the refrigerant pipe 4 . The gas-liquid two-phase refrigerant flowing into the first relay unit 3a flows into the gas-liquid separator 14, is separated into gas refrigerant and liquid refrigerant, and flows into the second relay unit 3b.

The gas refrigerant separated in the gas-liquid separator 14 flows into the first intermediate heat exchanger 15a. The gas refrigerant flowing into the first intermediate heat exchanger 15a is condensed and liquefied while dissipating heat to the heat medium circulating in the heat medium circuit, and turns into a liquid refrigerant. The liquid refrigerant flowing out of the second intermediate heat exchanger 15b passes through the expansion valve 16d. On the other hand, the liquid refrigerant separated in the gas-liquid separator 14 passes through the expansion valve 16e, merges with the liquid refrigerant condensed and liquefied in the first intermediate heat exchanger 15a and passed through the expansion valve 16d, and is absorbed by the expansion valve 16a. It is throttled and expanded to become a low-temperature, low-pressure gas-liquid two-phase refrigerant, which flows into the second intermediate heat exchanger 15b.

This gas-liquid two-phase refrigerant absorbs heat from the heat medium circulating in the heat medium circulation circuit in the second intermediate heat exchanger 15b functioning as an evaporator, and turns the heat medium into a low-temperature and low-pressure gas while cooling the heat medium. Refrigerant. The gas refrigerant flowing out of the second intermediate heat exchanger 15b passes through the expansion valve 16c, flows out from the second relay unit 3b and the first relay unit 3a, and flows into the heat source device 1 through the refrigerant pipe 4. The refrigerant flowing into the heat source device 1 passes through the check valve 13d, passes through the four-way valve 11 and the accumulator 17, and is sucked into the compressor 10 again. In addition, the expansion valve 16b has a small opening so that the refrigerant does not flow, and the expansion valve 16c is fully open so that no pressure loss occurs.

Next, the flow of the heat medium in the heat medium circulation circuit will be described.

In the cooling main operation mode, since both the first pump 21a and the second pump 21b are driven, the heat medium circulates through both the piping 5a and the piping 5b. The heat medium heated by the heat source side refrigerant in the first intermediate heat exchanger 15a flows through the pipe 5a by the first pump 21a. In addition, the heat medium cooled by the heat source side refrigerant in the second intermediate heat exchanger 15b flows through the pipe 5b by the second pump 21b.

The heat medium that has been pressurized by the first pump 21a and flowed out passes through the flow path switching valve 22a, passes through the shutoff valve 24a, and flows into the use-side heat exchanger 26a. Then, heat is supplied to the indoor air in the use-side heat exchanger 26a, and heat is supplied to an air-conditioning target area such as a room where the indoor unit 2 is installed. In addition, the heat medium that has been pressurized by the second pump 21b and flowed out passes through the flow path switching valve 22b, passes through the shutoff valve 24b, and flows into the use-side heat exchanger 26b. Then, the use-side heat exchanger 26b absorbs heat from the indoor air, and cools an air-conditioning target area such as a room where the indoor unit 2 is installed.

The heated heat medium flows into the flow regulating valve 25a. At this time, by virtue of the function of the flow regulating valve 25a, only the heat medium of the flow rate required to supply the air-conditioning load required by the air-conditioning target area flows into the use-side heat exchanger 26a, and the rest of the heat medium bypasses through the bypass 27a. It flows through the use side heat exchanger 26a. The heat medium passing through the bypass 27a does not participate in heat exchange, but merges with the heat medium passing through the use-side heat exchanger 26a, passes through the flow path switching valve 23a, flows into the first intermediate heat exchanger 15a, and is sucked into the first pump 21a.

Similarly, the cooled heat medium flows into the flow rate adjustment valve 25b. At this time, with the help of the flow regulating valve 25b, only the heat medium of the flow rate required to supply the air-conditioning load required by the air-conditioning target area flows into the use-side heat exchanger 26b, and the rest of the heat medium bypasses the use side through the bypass 27b. The heat exchanger 26b flows. The heat medium passing through the bypass 27b does not participate in heat exchange, but merges with the heat medium passing through the use-side heat exchanger 26b, passes through the flow path switching valve 23b, flows into the second intermediate heat exchanger 15b, and is sucked into the second pump 21b.

During this period, the hot heat medium (the heat medium used for the heat energy load) and the cold heat medium (the heat medium used for the cold energy load) pass through the flow path switching valve 22 (the flow path switching valve 22a and the flow path switching valve 22b) and the flow path switching valve 23 (flow path switching valve 23a and flow path switching valve 23b), flow into the use-side heat exchanger 26a with thermal energy load and the use-side heat exchanger 26b with cooling energy load without mix. In addition, by controlling and maintaining the temperature difference between the third temperature sensor 33 and the fourth temperature sensor 34 at a target value, the air-conditioning load required for an air-conditioning target area such as a room can be supplied.

At this time, since it is not necessary to let the heat medium flow into the use-side heat exchanger 26 without thermal energy load (including heat stop), the flow path is closed with the stop valve 24 so that the heat medium does not flow into the use-side heat exchanger 26 . In FIG. 9, since there is a heat load in the use-side heat exchanger 26a and the use-side heat exchanger 26b, the heat medium flows, but there is no heat in the use-side heat exchanger 26c and the use-side heat exchanger 26d. Therefore, the corresponding shutoff valve 24c and shutoff valve 24d are closed. When a heating load or a cooling load is generated from the use-side heat exchanger 26c or 26d, the stop valve 24c or the stop valve 24d may be opened to circulate the heat medium.

[Main heating operation mode]

FIG. 10 is a refrigerant circuit diagram showing the flow of refrigerant during the heating main operation mode of the air-conditioning apparatus 100 . In FIG. 10 , the heating-main operation mode will be described by taking, as an example, a case where a heating load is generated in the use-side heat exchanger 26a and a cooling load is generated in the use-side heat exchanger 26b. That is, in FIG. 10 , the case where both the heating load and the cooling load are not generated in the use-side heat exchanger 26c and the use-side heat exchanger 26d is shown. In addition, in FIG. 10 , pipes indicated by thick lines are pipes through which refrigerant (heat source side refrigerant and heat medium) circulates. In addition, 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 dotted line arrow.

In the heating main operation mode shown in FIG. 10 , in the heat source device 1 , the four-way valve 11 is switched so that the heat source side refrigerant discharged from the compressor 10 flows into the relay unit 3 without passing through the heat source side heat exchanger 12 . . In the relay unit 3, the first pump 21a and the second pump 21b are driven, the shutoff valve 24a and the shutoff valve 24b are opened, the shutoff valve 24c and the shutoff valve 24d are closed, and the heat medium exchanges heat with the use side in the first intermediate heat exchanger 15a between the heat exchangers 26a, and between the second intermediate heat exchanger 15b and the use-side heat exchanger 26b. In this state, the operation of the compressor 10 is started.

First, the flow of the heat source side refrigerant in the refrigeration cycle will be described.

The low-temperature, low-pressure refrigerant is compressed by the compressor 10 to become a high-temperature, high-pressure gas refrigerant, and then discharged. The high-temperature, high-pressure gas refrigerant discharged from the compressor 10 passes through the four-way valve 11, flows through the first connecting pipe 4a, passes through the check valve 13b, and flows out of the heat source device 1. The high-temperature, high-pressure gas refrigerant flowing out of the heat source device 1 flows into the first relay unit 3 a through the refrigerant pipe 4 . The high-temperature, high-pressure gas refrigerant flowing into the first relay unit 3a flows into the gas-liquid separator 14, and then flows into the first intermediate heat exchanger 15a through the expansion valve 16e. The high-temperature, high-pressure gas refrigerant that has flowed into the first intermediate heat exchanger 15a is condensed and liquefied while dissipating heat to the heat medium circulating in the heat medium circuit to become a high-pressure liquid refrigerant.

The high-pressure liquid refrigerant flowing out of the first intermediate heat exchanger 15a is throttled and expanded by the expansion valve 16d, and becomes a low-temperature, low-pressure gas-liquid two-phase state. The refrigerant in the gas-liquid two-phase state throttled by the expansion valve 16d is divided into a flow path passing through the expansion valve 16a and a flow path passing through the expansion valve 16b. The refrigerant passing through the expansion valve 16a is further expanded by the expansion valve 16a, becomes a low-temperature, low-pressure gas-liquid two-phase refrigerant, and flows into the second intermediate heat exchanger 15b functioning as an evaporator. Then, the refrigerant flowing into the second intermediate heat exchanger 15b absorbs heat from the heat medium in the second intermediate heat exchanger 15b to become a low-temperature, low-pressure gas refrigerant. The low-temperature, low-pressure gas refrigerant flowing out of the second intermediate heat exchanger 15b passes through the expansion valve 16c.

On the other hand, the refrigerant flowing into the expansion valve 16b after being throttled by the expansion valve 16d merges with the refrigerant passing through the second intermediate heat exchanger 15b and the expansion valve 16c to become a low-temperature, low-pressure refrigerant with a higher dryness. agent. Then, the merged refrigerant flows out from the second relay unit 3 b and the first relay unit 3 a, and flows into the heat source device 1 through the refrigerant pipe 4 . The refrigerant flowing into the heat source device 1 passes through the check valve 13c, flows through the second connecting pipe 4b, and flows into the heat source side heat exchanger 12 functioning as an evaporator. Then, the refrigerant flowing into the heat source side heat exchanger 12 absorbs heat from the outdoor air in the heat source side heat exchanger 12 to become a low-temperature, low-pressure gas refrigerant. The low-temperature, low-pressure gas refrigerant flowing out of the heat source side heat exchanger 12 returns to the compressor 10 through the four-way valve 11 and the accumulator 17 . In addition, the expansion valve 16e has a small opening so that the refrigerant does not flow.

Next, the flow of the heat medium in the heat medium circulation circuit will be described.

In the heating main operation mode, since both the first pump 21a and the second pump 21b are driven, the heat medium circulates through both the piping 5a and the piping 5b. The heat medium heated by the heat source side refrigerant in the first intermediate heat exchanger 15a flows through the pipe 5a by the first pump 21a. In addition, the heat medium cooled by the heat source side refrigerant in the second intermediate heat exchanger 15b flows through the pipe 5b by the second pump 21b.

The heat medium that has been pressurized by the first pump 21a and flowed out passes through the flow path switching valve 22a, passes through the shutoff valve 24a, and flows into the use-side heat exchanger 26a. Then, heat is supplied to the indoor air in the use-side heat exchanger 26a, and heat is supplied to an air-conditioning target area such as a room where the indoor unit 2 is installed. In addition, the heat medium that has been pressurized by the second pump 21b and flowed out passes through the flow path switching valve 22b, passes through the shutoff valve 24b, and flows into the use-side heat exchanger 26b. Then, the use-side heat exchanger 26b absorbs heat from the indoor air, and cools an air-conditioning target area such as a room where the indoor unit 2 is installed.

The heat medium flowing out of the use-side heat exchanger 26a flows into the flow regulating valve 25a. At this time, with the help of the flow regulating valve 25a, only the heat medium of the flow rate required to supply the air-conditioning load required by the air-conditioning target area such as indoors flows into the use-side heat exchanger 26a, and the rest of the heat medium bypasses through the bypass 27a. It flows through the use side heat exchanger 26a. The heat medium passing through the bypass 27a does not participate in heat exchange, but merges with the heat medium passing through the use-side heat exchanger 26a, passes through the flow path switching valve 23a, flows into the first intermediate heat exchanger 15a, and is sucked into the first pump 21a.

Similarly, the heat medium flowing out of the use-side heat exchanger 26b flows into the flow rate adjustment valve 25b. At this time, with the help of the flow regulating valve 25b, only the heat medium of the flow rate required to supply the air-conditioning load required by the air-conditioning target area such as indoors flows into the use-side heat exchanger 26b, and the rest of the heat medium bypasses through the bypass 27b. It flows through the use side heat exchanger 26b. The heat medium passing through the bypass 27b does not participate in heat exchange, but merges with the heat medium passing through the use-side heat exchanger 26b, passes through the flow path switching valve 23b, flows into the second intermediate heat exchanger 15b, and is sucked into the second pump 21b.

During this period, the hot heat medium and the cold heat medium flow through the flow path switching valve 22 (flow path switching valve 22a and flow path switching valve 22b) and the flow path switching valve 23 (flow path switching valve 23a and flow path switching valve Under the action of 23b), it flows into the use-side heat exchanger 26a with thermal energy load and the use-side heat exchanger 26b with cooling energy load without mixing. In addition, by controlling and maintaining the temperature difference between the third temperature sensor 33 and the fourth temperature sensor 34 at a target value, the air-conditioning load required for an air-conditioning target area such as a room can be supplied.

At this time, since it is not necessary to flow the heat medium into the use-side heat exchanger 26 with no heat load (including heat stop), the flow path is closed with the stop valve 24 so that the heat medium does not flow into the use-side heat exchanger 26 . In Fig. 10, in the use-side heat exchanger 26a and the use-side heat exchanger 26b, since there is a heat energy load, the heat medium flows, but in the use-side heat exchanger 26c and the use-side heat exchanger 26d, there is no The thermal energy load makes the corresponding shut-off valve 24c and shut-off valve 24d into a closed state. When a heating load or a cooling load is generated from the use-side heat exchanger 26c or 26d, the stop valve 24c or the stop valve 24d may be opened to circulate the heat medium.

As described above, the gas-liquid separator 14 is provided in the first relay unit 3a to separate the gas refrigerant and the liquid refrigerant, so two refrigerants can be used between the heat source device 1 and the first relay unit 3a. The pipes 4 are connected, and simultaneous cooling and heating operations are performed. In addition, by switching and controlling the flow path switching valve 22, flow path switching valve 23, stop valve 24, and flow regulating valve 25 on the side of the heat supply medium, the cold energy or heat energy generated in the heat source device 1 can be supplied to the load through the heat medium. Therefore, on the load side, cooling energy or heating energy can be freely supplied to each use-side heat exchanger 26 by using two pipes 5 .

In addition, the relay unit 3 (the first relay unit 3a and the second relay unit 3b) is a housing separate from the heat source device 1 and the indoor unit 2, so the relay unit 3 can be installed in a position different from them, As shown in FIG. 1, if the first relay unit 3a and the second relay unit 3b are installed in the non-residential space 50, the heat source side refrigerant and the heat medium can be separated, and the heat source side refrigerant can be prevented from flowing into the residential space 7. , to improve the safety and reliability of the air conditioning device 100 .

In the first intermediate heat exchanger 15a on the heating side, the temperature of the heat medium at the outlet of the first intermediate heat exchanger 15a detected by the first temperature sensor 31a is not higher than the first temperature detected by the second temperature sensor 32a. The temperature of the heat medium at the inlet of the intermediate heat exchanger 15a and the heating amount of the superheated gas region of the heat source side refrigerant are small. Therefore, the temperature of the heat medium at the outlet of the first intermediate heat exchanger 15 a is limited by the condensation temperature obtained approximately from the saturation temperature of the first pressure sensor 36 . In addition, in the second intermediate heat exchanger 15b on the cooling side, the temperature of the heat medium at the outlet of the second intermediate heat exchanger 15b detected by the first temperature sensor 31b is not lower than the temperature of the second intermediate heat exchanger 15b detected by the second temperature sensor 32b. 2The temperature of the heat medium at the inlet of the intermediate heat exchanger 15b.

Therefore, in the air-conditioning apparatus 100, by changing the condensing temperature or the evaporating temperature on the refrigeration cycle side, it is possible to effectively respond to an increase or decrease in heat load on the secondary side (use side). Therefore, it is desirable to change the control target value of the condensation temperature and/or the evaporation temperature of the refrigeration cycle stored in the control device (not shown) according to the magnitude of the heat load on the use side. In this way, it is possible to easily follow a change in the magnitude of the thermal load on the usage side.

The control device connected to the second relay unit 3b performs grasping of the change of the thermal load on the usage side. On the other hand, the control target values of the condensation temperature and the evaporation temperature are stored in a control device connected to the heat source device 1 including the compressor 10 and the heat source side heat exchanger 12 . For this reason, connect the signal line between the control device connected with the 2nd relay unit 3b and the control device connected with the heat source device 1, utilize communication, send the control target value of condensing temperature or/and evaporating temperature, change and store in and The control target value of the condensation temperature or/and evaporation temperature in the control device connected to the heat source device 1 . In addition, a deviation value of the control target value may be communicated to change the control target value.

By performing such control, it is possible to appropriately respond to changes in the heat load on the usage side. That is, the control device can control the driving frequency of the compressor 10 so that the workload of the compressor 10 can be reduced when the heat load on the usage side is reduced. Therefore, more energy-saving operation can be performed in the air-conditioning apparatus 100 . In addition, the control device connected to the second relay unit 3b and the control device connected to the heat source device 1 may be implemented by one control device.

In Embodiment 1, as the heat source side refrigerant, as described above, it was exemplified that pseudo azeotropic mixed refrigerants such as R410A and R404A, non-azeotropic mixed refrigerants such as R407C, and CF3CF= It may be a refrigerant with a relatively small global warming coefficient such as CH2 or a mixture thereof, or a natural refrigerant such as carbon dioxide or propane, but it is not limited to the refrigerants exemplified here. In addition, in Embodiment 1, an example of the case where the accumulator 17 is provided in the heat source device 1 was described, but the same operation can be performed without providing the accumulator 17 , and the same effect can be obtained.

In addition, generally, the heat source side heat exchanger 12 and the use side heat exchanger 26 are provided with an air blower such as a fan to promote condensation or evaporation by air blowing, but the present invention is not limited thereto. For example, a heat exchanger such as a plate heater using radiation can be used as the use-side heat exchanger 26, and a water-cooled heat exchanger that transfers heat through water or antifreeze can be used as the heat source-side heat exchanger 12. It is a structure that can dissipate heat or absorb heat, and any form of heat exchanger can be used.

Although the case where the flow path switching valve 22, the flow path switching valve 23, the stop valve 24, and the flow rate adjustment valve 25 are respectively provided corresponding to each use-side heat exchanger 26 has been described as an example, the present invention is not limited thereto. . For example, it is also possible to connect a plurality of the above-mentioned components to one use-side heat exchanger 26. 24 and the flow regulating valve 25 can perform the same action. In addition, although the case where two intermediate heat exchangers 15 are provided has been described as an example, of course, the number is not limited, and three or more intermediate heat exchangers 15 may be provided as long as the heat medium can be cooled or/and heated.

In addition, the flow regulating valve 25, the third temperature sensor 33, and the fourth temperature sensor 34 are arranged inside the second relay unit 3b, but some or all of them may be arranged in the indoor unit 2. Inside. When they are arranged in the second relay unit 3b, since the valves and pumps on the heat medium side are integrated in the same housing, there is an advantage of easy maintenance. On the other hand, when they are arranged in the indoor unit 2, they can be used in the same way as the expansion valve of the conventional direct expansion indoor unit, so it is easy to use, and since they are installed near the heat exchanger 26 on the use side, , will not be affected by the heat loss of the extension pipe, and the controllability of the heat load in the indoor unit 2 is good.

As described above, the air-conditioning apparatus 100 according to the first embodiment transmits the thermal energy or/and cold energy of the refrigeration cycle to the use-side heat exchanger 26 via the plurality of intermediate heat exchangers 15, so the outdoor frame ( The heat source device 1) is installed in the outdoor space 6 on the outdoor side, the indoor frame (indoor unit 2) is installed in the indoor living space 7, and the heat medium conversion frame (relay unit 3) is installed in the non-residential space 50 , can prevent the heat source side refrigerant from entering the living space 7, and improve the safety and reliability of the system.

In addition, the air-conditioning apparatus 100 makes heat medium such as water and salt water flow in the heat medium circulation circuit, so the amount of refrigerant on the heat source side can be greatly reduced, and the impact on the environment when the refrigerant leaks can be greatly reduced. In addition, in the air conditioner 100, by connecting the relay unit 3 and each of the plurality of indoor units 2 with two heat medium pipes (pipes 5), the transmission power of water can be reduced, saving energy, and the installation process is easy. In addition, the air conditioner 100 can reduce the size of the expansion tank 60 by limiting the relationship between the relay unit 3 and the indoor unit 2 and the water supply pressure of the water pipe 62, and finally the relay unit 3 can be miniaturized and handled easily.

Embodiment 2

FIG. 11 is a circuit diagram showing a circuit configuration of an air-conditioning apparatus 200 according to Embodiment 2 of the present invention. Next, the circuit configuration of the air-conditioning apparatus 200 will be described with reference to FIG. 11 . The air-conditioning apparatus 200 refrigerates using a refrigeration cycle (a refrigeration cycle circuit and a heat medium circulation circuit) that circulates a refrigerant (a heat-source-side refrigerant and a heat medium (water, antifreeze, etc.)) in the same manner as the air-conditioning apparatus 100 . running or heating. This air-conditioning apparatus 200 is different from the air-conditioning apparatus 100 of Embodiment 1 in that the refrigerant piping is a three-pipe system. In addition, in Embodiment 2, the difference from Embodiment 1 will be mainly described, and the same parts as Embodiment 1 will be assigned the same symbols, and the description will be omitted.

As shown in FIG. 11 , the air conditioner 200 has one heat source device 101 as a heat source device, a plurality of indoor units 102 , and a relay unit 103 interposed between the heat source device 101 and the indoor units 102 . The relay unit 103 performs heat exchange between the refrigerant and the heat medium on the heat source side. The heat source device 101 and the relay unit 103 are connected by the refrigerant pipe 108 that conducts the heat source side refrigerant, and the relay unit 103 and the indoor unit 102 are connected by the pipe 5 that conducts the heat medium, and the cooling energy generated in the heat source device 101 or The thermal energy is distributed to the indoor unit 102 . In addition, the number of connected heat source devices 101, indoor units 102, and relay units 103 is not limited to the number shown in the figure.

The heat source device 101 is arranged in the outdoor space 6 as shown in FIG. 1 , and supplies cooling energy or heating energy to the indoor unit 102 through the relay unit 103 . The indoor unit 102 is arranged in the living space 7 as shown in FIG. 1 , and supplies cooling air or heating air to the living space 7 which is an area to be air-conditioned. The relay unit 103 is configured separately from the heat source device 101 and the indoor unit 102, is arranged in the non-residential space 50, connects the heat source device 101 and the indoor unit 102, and transfers the cold energy or heat energy supplied from the heat source device 101 to the indoor unit 102. .

The heat source device 101 and the relay unit 103 are connected by three refrigerant pipes 108 (refrigerant pipes 108a to 108c). In addition, the relay unit 103 and each indoor unit 102 are connected by two pipes 5, respectively. In this way, the construction of the air-conditioning apparatus 200 is easy. That is, the heat source device 101 and the relay unit 103 are connected via the first intermediate heat exchanger 15 a and the second intermediate heat exchanger 15 b included in the relay unit 103 . The relay unit 103 and the indoor unit 102 are also connected via the first intermediate heat exchanger 15a and the second intermediate heat exchanger 15b. Next, the configuration and function of each component device provided in the air-conditioning apparatus 200 will be described.

[Heat source device 101]

In the heat source device 101, a compressor 110 connected by a refrigerant pipe 108, an oil separator 111, a check valve 113, and a three-way valve 104 (three-way valve 104a and three-way valve 104b) serving as a refrigerant flow switching device are accommodated. , heat source side heat exchanger 105 and expansion valve 106 . In addition, the heat source device 101 is provided with two-way valves 107 (two-way valve 107a, two-way valve 107b, and two-way valve 107c). In this heat source device 101, the flow direction of the heat source side refrigerant is determined by controlling the three-way valve 104a and the three-way valve 104b.

The compressor 110 sucks in the heat source side refrigerant, compresses the heat source side refrigerant to a high temperature and high pressure state, and may be constituted by, for example, a capacity-controllable inverter compressor or the like. The oil separator 111 is provided on the discharge side of the compressor 110 and separates refrigerating machine oil contained in the refrigerant discharged from the compressor 110 . Check valve 113 is provided on the downstream side of oil separator 111 and allows only a predetermined direction (direction from oil separator 111 to three-way valve 104 ) of the heat source side refrigerant passing through oil separator 111 .

The three-way valve 104 is used to switch the flow of the heat source side refrigerant during the heating operation and the flow of the heat source side refrigerant during the cooling operation. The three-way valve 104a is provided on one of the refrigerant pipes 108 branched on the downstream side of the check valve 113, one of the three-way is connected to the check valve 113, and the other is connected to the intermediate heat exchanger 15 via the two-way valve 107b. , and one side is connected to the intermediate heat exchanger 15 via the two-way valve 107c. The three-way valve 104b is provided on the other side of the refrigerant piping 108 branched on the downstream side of the check valve 113. One of the three-way valves is connected to the check valve 113, one is connected to the heat source side heat exchanger 105, and the other is connected to the compressor. The refrigerant piping 108 between the machine 110 and the three-way valve 104a and the two-way valve 107c is connected.

The heat source side heat exchanger 105 functions as an evaporator during the heating operation and as a condenser during the cooling operation, and conducts heat transfer between air supplied from a blower such as a fan (not shown) and the heat source side refrigerant. Heat exchange, the refrigerant on the heat source side evaporates into gasification or condenses into liquefaction. The expansion valve 106 is provided on the refrigerant pipe 108 connecting the heat source side heat exchanger 105 and the intermediate heat exchanger 15, and functions as a pressure reducing valve and a throttling device to decompress and expand the heat source side refrigerant. The expansion valve 106 can be composed of, for example, an electronic expansion valve whose opening degree can be variably controlled.

The two-way valve 107 is used to open and close the refrigerant piping 108 . The two-way valve 107a is provided in a refrigerant pipe 108a between the expansion valve 106 and an expansion valve 203 described later. The two-way valve 107b is provided in the refrigerant pipe 108b between the three-way valve 104a and a two-way valve 204b described later. The two-way valve 107c is provided in the refrigerant piping 108c between the three-way valve 104a and a two-way valve 205b described later. The refrigerant pipe 108a is a high-pressure liquid pipe, the refrigerant pipe 108b is a high-pressure gas pipe, and the refrigerant pipe 108c is a low-pressure gas pipe.

[Indoor unit 102]

A use-side heat exchanger 26 is mounted on each indoor unit 102 . The use-side heat exchanger 26 is connected to the shutoff valve 24 and the flow control valve 25 of the relay unit 103 through the pipe 5 . In this Fig. 11, the case where six indoor units 102 are connected to the relay unit 103 is shown as an example, and the indoor unit 102a, the indoor unit 102b, the indoor unit 102c, the indoor unit 102d, the indoor machine 102e, indoor unit 102f.

In addition, the use-side heat exchanger 26 corresponds to the indoor units 102a to 102f, and sequentially shows a use-side heat exchanger 26a, a use-side heat exchanger 26b, a use-side heat exchanger 26c, and a use-side heat exchanger from the bottom of the drawing. Heat exchanger 26d, use-side heat exchanger 26e, and use-side heat exchanger 26f. In addition, similarly to Embodiment 1, the number of connected indoor units 102 is not limited to six as shown in FIG. 11 . In addition, the use-side heat exchanger 26 is the same as the use-side heat exchanger housed in the indoor unit 2 of the air-conditioning apparatus 100 according to the first embodiment.

[relay unit 103]

The relay unit 103 is provided with 2 expansion valves 203, 2 intermediate heat exchangers 15, 2 two-way valves 204, 2 two-way valves 205, 2 pumps 21, 6 flow path switching valves 22, and 6 Flow path switching valve 23 , six cut-off valves 24 and six flow regulating valves 25 . In addition, the intermediate heat exchanger 15, the pump 21, the channel switching valve 22, the channel switching valve 23, the shutoff valve 24, and the flow regulating valve 25 are connected to the second relay unit 3b housed in the air-conditioning apparatus 100 according to the first embodiment. parts are the same.

The two expansion valves 203 (expansion valve 203a and expansion valve 203b) function as pressure reducing valves and throttling devices, and decompress and expand the heat source side refrigerant. The expansion valve 203a is provided between the two-way valve 107a and the first intermediate heat exchanger 15a. The expansion valve 203b is provided in parallel with the expansion valve 203a between the two-way valve 107a and the second intermediate heat exchanger 15b. The two expansion valves 203 may be composed of, for example, electronic expansion valves whose opening degrees can be variably controlled.

The two two-way valves 204 (two-way valve 204 a and two-way valve 204 b ) are used to open and close the refrigerant pipe 108 . The two-way valve 204a is provided in the refrigerant pipe 108b between the two-way valve 107b and the first intermediate heat exchanger 15a. The two-way valve 204b is provided in parallel with the two-way valve 204a on the refrigerant pipe 108b between the two-way valve 107b and the second intermediate heat exchanger 15b. Moreover, the two-way valve 204a is provided in the refrigerant piping 108b branched from the refrigerant piping 108b between the two-way valve 107b and the two-way valve 204b.

The two two-way valves 205 (two-way valve 205 a and two-way valve 205 b ) are used to open and close the refrigerant pipe 108 . The two-way valve 205a is provided in the refrigerant pipe 108c between the two-way valve 107c and the first intermediate heat exchanger 15a. The two-way valve 205b is provided in parallel with the two-way valve 205a on the refrigerant pipe 108c between the two-way valve 107c and the second intermediate heat exchanger 15b. Moreover, the two-way valve 205a is provided in the refrigerant piping 108c branched from the refrigerant piping 108c between the two-way valve 107c and the two-way valve 205b.

In addition, in the relay unit 103, like the second relay unit 3b of the air-conditioning apparatus 100 of Embodiment 1, two first temperature sensors 31, two second temperature sensors 32, and six third temperature sensors are provided. 33. Six fourth temperature sensors 34, fifth temperature sensors 35, first pressure sensors 36, sixth temperature sensors 37, and seventh temperature sensors 38. In addition, the relay unit 103 is provided with an eighth temperature sensor 39 and a second pressure sensor 40 . The information detected by these detection mechanisms is sent to a control device (not shown) that collectively controls the entire air-conditioning apparatus 200, and is used for the driving frequency of the compressor 110 and the pump 21, the flow path switching of the heat medium flowing through the piping 5, and the like. control.

The eighth temperature sensor 39 is provided on the inlet side of the heat-source-side refrigerant flow path of the first intermediate heat exchanger 15a, and is used to detect the temperature of the heat-source-side refrigerant flowing into the first intermediate heat exchanger 15a, and may be composed of a thermistor or the like. . The second pressure sensor 40 is provided on the outlet side of the heat source side refrigerant passage of the second intermediate heat exchanger 15b, and detects the pressure of the heat source side refrigerant flowing out of the second intermediate heat exchanger 15b. In addition, the first pressure sensor 36 functions as a heating pressure sensor, and the second pressure sensor 40 functions as a cooling pressure detection means.

In this air-conditioning apparatus 200, the compressor 110, the oil separator 111, the heat source side heat exchanger 105, the expansion valve 106, the first intermediate heat exchanger 15a, and the second intermediate heat exchanger 15b are connected through the refrigerant piping 108. Connected in series to form a refrigeration cycle. In addition, the first intermediate heat exchanger 15a, the first pump 21a, and the use-side heat exchanger 26 are sequentially connected in series through the piping 5a to constitute a heat medium circulation circuit. Similarly, the second intermediate heat exchanger 15b, the second pump 21b, and the use-side heat exchanger 26 are sequentially connected in series through the piping 5b to constitute a heat medium circulation circuit.

That is, in the air conditioner 200, the heat source device 101 and the relay unit 103 are connected via the first intermediate heat exchanger 15a and the second intermediate heat exchanger 15b provided in the relay unit 103, and the relay unit 103 and the indoor unit 102 Connected by the first intermediate heat exchanger 15a and the second intermediate heat exchanger 15b, the heat source side refrigerant which is the primary side refrigerant circulating in the refrigeration cycle and the secondary side refrigerant which is circulated in the heat medium circuit are connected. The heat medium of the refrigerant exchanges heat between the first intermediate heat exchanger 15a and the second intermediate heat exchanger 15b.

Here, each operation mode performed by the air-conditioning apparatus 200 will be described.

In this air-conditioning apparatus 200, according to instructions from each indoor unit 102, the indoor unit 102 can perform a cooling operation or a heating operation. That is, the air-conditioning apparatus 200 may perform the same operation with all the indoor units 102, or may perform different operations with each indoor unit 102, respectively. Next, the flow of the refrigerant in the four operation modes executed by the air-conditioning apparatus 200 , namely, the cooling only operation mode, the heating only operation mode, the cooling main operation mode, and the heating main operation mode will be described.

[Full cooling operation mode]

FIG. 12 is a refrigerant circuit diagram showing the refrigerant flow in the cooling only operation mode of the air-conditioning apparatus 200 . In FIG. 12 , the cooling only operation mode will be described by taking a case where all the use-side heat exchangers 26a to 26f generate cooling energy loads as an example. In addition, in FIG. 12 , pipes indicated by thick lines are pipes through which refrigerant (heat source side refrigerant and heat medium) circulates. In addition, 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 dotted line arrow.

In the cooling only operation mode shown in FIG. 12, in the heat source device 101, the three-way valve 104b is switched so that the heat-source-side refrigerant discharged from the compressor 110 flows into the heat-source-side heat exchanger 105, and the three-way valve 104a is switched so that The heat source side refrigerant passing through the second intermediate heat exchanger 15b is sucked into the compressor 110, the two-way valve 107a and the two-way valve 107b are opened, and the two-way valve 107c is closed. In the relay unit 103 , the first pump 21 a is stopped, the second pump 21 b is driven, the shutoff valve 24 is opened, and the heat medium circulates between the second intermediate heat exchanger 15 b and each use-side heat exchanger 26 . In this state, the operation of the compressor 110 is started.

First, the flow of refrigerant on the heat source side of the refrigeration cycle will be described.

The low-temperature, low-pressure refrigerant is compressed by the compressor 110 to become a high-temperature, high-pressure gas refrigerant, and then discharged. The high-temperature, high-pressure gas refrigerant discharged from the compressor 110 flows into the heat source side heat exchanger 105 through the three-way valve 104b. Then, in the heat source side heat exchanger 105 , it is condensed and liquefied while dissipating heat to the outdoor air to become a high-pressure liquid refrigerant. The high-pressure liquid refrigerant flowing out of the heat source side heat exchanger 105 flows out of the heat source device 101 through the two-way valve 107a, and flows into the relay unit 103 through the refrigerant pipe 108a. The high-pressure liquid refrigerant flowing into the relay unit 103 is throttled and expanded by the expansion valve 203b to become a low-temperature, low-pressure gas-liquid two-phase refrigerant.

This gas-liquid two-phase refrigerant flows into the second intermediate heat exchanger 15b functioning as an evaporator, absorbs heat from the heat medium circulating in the heat medium circuit, and turns the heat medium into a low-temperature, low-pressure gas refrigerant while cooling the heat medium. . The gas refrigerant flowing out of the second intermediate heat exchanger 15b flows out of the relay unit 103 through the two-way valve 205b, and flows into the heat source device 101 through the refrigerant pipe 108c. The refrigerant that has flowed into the heat source device 101 passes through the two-way valve 107c, passes through the three-way valve 104a, and is sucked into the compressor 110 again.

Next, the flow of the heat medium in the heat medium circulation circuit will be described.

In the cooling only operation mode, since the first pump 21a is stopped, the heat medium circulates through the piping 5b. The heat medium cooled by the heat source side refrigerant in the second intermediate heat exchanger 15b flows through the pipe 5b by the second pump 21b. The heat medium that has been pressurized by the second pump 21 b and flowed out passes through the flow path switching valve 22 , passes through the shutoff valve 24 , and flows into each use-side heat exchanger 26 . Then, the use-side heat exchanger 26 absorbs heat from the indoor air, and cools an air-conditioned area such as a room where the indoor unit 102 is installed.

Then, the heat medium flowing out from each use-side heat exchanger 26 flows into the flow rate adjustment valve 25 . At this time, with the help of the flow regulating valve 25, only the heat medium of the flow rate required to supply the air-conditioning load required by the air-conditioning target area such as indoors flows into the use-side heat exchanger 26, and the rest of the heat medium is bypassed through the bypass 27. Use side heat exchanger 26 to flow. The heat medium passing through the bypass 27 does not participate in heat exchange, but merges with the heat medium passing through the use-side heat exchanger 26, passes through the channel switching valve 23, flows into the second intermediate heat exchanger 15b, and is sucked into the second pump 21b. In addition, by controlling and maintaining the temperature difference between the third temperature sensor 33 and the fourth temperature sensor 34 at a target value, the air-conditioning load required for an air-conditioning target area such as a room can be supplied.

[Full heating operation mode]

FIG. 13 is a refrigerant circuit diagram showing the refrigerant flow in the heating only operation mode of the air-conditioning apparatus 200 . In this FIG. 13 , the heating only operation mode will be described by taking a case where all the use-side heat exchangers 26 a to 26 f generate thermal energy loads as an example. In addition, in FIG. 8 , pipes indicated by thick lines are pipes through which refrigerant (heat source side refrigerant and heat medium) circulates. In addition, 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 dotted line arrow.

In the heating only operation mode shown in FIG. 13, in the heat source device 101, the three-way valve 104a is switched so that the heat source side refrigerant discharged from the compressor 110 flows into the first intermediate heat exchanger 15a, and the three-way valve 104b is switched. , the heat source side refrigerant passing through the heat source side heat exchanger 105 is sucked into the compressor 110, the two-way valve 107a and the two-way valve 107b are opened, and the two-way valve 107c is closed. In the relay unit 103 , the first pump 21 a is driven, the second pump 21 b is stopped, the shutoff valve 24 is opened, and the heat medium circulates between the second intermediate heat exchanger 15 b and each use-side heat exchanger 26 . In this state, the operation of the compressor 110 is started.

First, the flow of refrigerant on the heat source side of the refrigeration cycle will be described.

The low-temperature, low-pressure refrigerant is compressed by the compressor 110 to become a high-temperature, high-pressure gas refrigerant, and then discharged. The high-temperature, high-pressure gas refrigerant discharged from the compressor 110 flows out of the heat source device 101 through the three-way valve 104a and the two-way valve 107b, and flows into the relay unit 103 through the refrigerant pipe 108a. The refrigerant that has flowed into the relay unit 103 flows into the first intermediate heat exchanger 15a through the two-way valve 204a. The high-temperature, high-pressure gas refrigerant that has flowed into the first intermediate heat exchanger 15a is condensed and liquefied while dissipating heat to the heat medium circulating in the heat medium circuit to become a high-pressure liquid refrigerant.

The high-pressure liquid refrigerant flowing out of the first intermediate heat exchanger 15a flows out of the relay unit 103 through the expansion valve 203a, and flows into the heat source device 101 through the refrigerant pipe 108a. The refrigerant that has flowed into the heat source device 101 flows into the expansion valve 106 through the two-way valve 107a, is throttled and expanded by the expansion valve 106, and becomes a low-temperature, low-pressure gas-liquid two-phase state. The refrigerant in the gas-liquid two-phase state throttled by the expansion valve 106 flows into the heat source side heat exchanger 105 functioning as an evaporator. The refrigerant that has flowed into the heat source side heat exchanger 105 absorbs heat from the outdoor air in the heat source side heat exchanger 105 to become a low-temperature, low-pressure gas refrigerant. The low-temperature, low-pressure gas refrigerant flowing out of the heat source side heat exchanger 105 returns to the compressor 110 through the three-way valve 104b.

Next, the flow of the heat medium in the heat medium circulation circuit will be described.

In the heating only operation mode, since the second pump 21b is stopped, the heat medium circulates through the piping 5b. The heat medium heated by the heat source side refrigerant in the first intermediate heat exchanger 15a flows through the pipe 5a by the first pump 21a. The heat medium that has been pressurized by the first pump 21 a and flowed out passes through the flow path switching valve 22 , passes through the shutoff valve 24 , and flows into each use-side heat exchanger 26 . Then, in the use-side heat exchanger 26 , heat is released to the indoor air, and heat is supplied to an air-conditioning target area such as a room where the indoor unit 2 is installed.

Then, the heat medium flowing out of the use-side heat exchanger 26 flows into the flow rate regulating valve 25 . At this time, with the help of the flow regulating valve 25, only the heat medium of the flow rate required to supply the air-conditioning load required by the air-conditioning target area such as indoors flows into the use-side heat exchanger 26, and the rest of the heat medium is bypassed through the bypass 27. Flow using side heat exchanger 26 . The heat medium passing through the bypass 27 does not participate in heat exchange, but merges with the heat medium passing through the use-side heat exchanger 26, passes through the channel switching valve 23, flows into the first intermediate heat exchanger 15a, and is sucked into the first pump 21a. In addition, by controlling and maintaining the temperature difference between the third temperature sensor 33 and the fourth temperature sensor 34 at a target value, the air-conditioning load required for an air-conditioning target area such as a room can be supplied.

[Main cooling operation mode]

FIG. 14 is a refrigerant circuit diagram showing the flow of the refrigerant during the cooling main operation mode of the air-conditioning apparatus 200 . In FIG. 14 , the main cooling operation mode will be described by taking, as an example, a case where heating loads are generated in the use-side heat exchangers 26a and 26b and cooling loads are generated in the use-side heat exchangers 26c to 26f. In addition, in FIG. 14 , pipes indicated by thick lines are pipes through which refrigerant (heat source side refrigerant and heat medium) circulates. In addition, 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 dotted line arrow.

In the main cooling operation mode shown in FIG. 14, in the heat source device 101, the three-way valve 104a is switched so that the heat source side refrigerant discharged from the compressor 110 flows into the first intermediate heat exchanger 15a, and the three-way valve 104b is switched, The heat source side refrigerant discharged from the compressor 110 flows into the heat source side heat exchanger 105, and the two-way valves 107a to 107c are opened. In the relay unit 103, the first pump 21a and the second pump 21b are driven, the shutoff valve 24 is opened, and the heat medium flows between the first intermediate heat exchanger 15a, the use-side heat exchanger 26a, and the use-side heat exchanger 26b. Circulation occurs between the second intermediate heat exchanger 15b and the use-side heat exchangers 26c to 26f. In this state, the operation of the compressor 110 is started.

First, the flow of refrigerant on the heat source side of the refrigeration cycle will be described.

The low-temperature, low-pressure refrigerant is compressed by the compressor 110 to become a high-temperature, high-pressure gas refrigerant, and then discharged. The high-temperature, high-pressure gas refrigerant discharged from the compressor 110 is branched on the downstream side of the check valve 113 . The divided refrigerant flows into the heat source side heat exchanger 105 through the three-way valve 104b. Then, in the heat source side heat exchanger 105, it is condensed and liquefied while radiating heat to the outdoor air, and becomes a high-pressure liquid refrigerant. The high-pressure liquid refrigerant flowing out of the heat source side heat exchanger 105 flows out of the heat source device 101 through the two-way valve 107a, and flows into the relay unit 103 through the refrigerant pipe 108a.

The branched refrigerant flows into the relay unit 103 through the refrigerant pipe 108b via the three-way valve 104a and the two-way valve 107b. The gas refrigerant that has flowed into the relay unit 103 flows into the first intermediate heat exchanger 15a through the two-way valve 204a. The high-temperature, high-pressure gas refrigerant that has flowed into the first intermediate heat exchanger 15a is condensed and liquefied while dissipating heat to the heat medium circulating in the heat medium circuit, and becomes a high-pressure liquid refrigerant. This liquid refrigerant merges with the refrigerant flowing into the relay unit 103 through the refrigerant pipe 108a.

The combined liquid refrigerant is throttled and expanded by the expansion valve 203b, and becomes a low-temperature, low-pressure gas-liquid two-phase refrigerant, and then flows into the second intermediate heat exchanger 15b which acts as an evaporator, and heats up in the second intermediate heat exchanger 15b. The exchanger 15b absorbs heat from the heat medium circulating in the heat medium circuit, and turns the heat medium into a low-temperature, low-pressure gas refrigerant while cooling the heat medium. The gas refrigerant flowing out of the second intermediate heat exchanger 15b flows out of the relay unit 103 through the two-way valve 205b, and flows into the heat source device 101 through the refrigerant pipe 108c. The refrigerant that has flowed into the heat source device 101 is sucked into the compressor 110 again through the two-way valve 107c.

Next, the flow of the heat medium in the heat medium circulation circuit will be described.

In the cooling main operation mode, since both the first pump 21a and the second pump 21b are driven, the heat medium circulates through both the piping 5a and the piping 5b. The heat medium heated by the heat source side refrigerant in the first intermediate heat exchanger 15a flows through the pipe 5a by the first pump 21a. In addition, the heat medium cooled by the heat source side refrigerant in the second intermediate heat exchanger 15b flows through the pipe 5b by the second pump 21b.

The heat medium that is pressurized and flowed out by the first pump 21a passes through the flow path switching valve 22a and the flow path switching valve 22b, passes through the stop valve 24a and the stop valve 24b, and flows into the use-side heat exchanger 26a and the use-side heat exchanger 26b. . Then, in the use-side heat exchanger 26a and the use-side heat exchanger 26b, heat is released to the indoor air, and heat is supplied to an air-conditioning target area such as a room where the indoor unit 102 is installed. In addition, the heat medium that has been pressurized and flowed out by the second pump 21b passes through the flow path switching valves 22c to 22f, passes through the shutoff valves 24c to 24f, and flows into the use side heat exchangers 26c to 26f. Then, the use-side heat exchangers 26c to 26f absorb heat from the indoor air to cool an air-conditioning target area such as a room where the indoor unit 102 is installed.

The heated heat medium flows into the flow rate adjustment valve 25a and the flow rate adjustment valve 25b. At this time, only the heat medium of the flow rate required to supply the air-conditioning load required for the air-conditioning target area flows into the use-side heat exchanger 26a and the use-side heat exchanger 26b by the action of the flow rate adjustment valve 25a and the flow rate adjustment valve 25b, The remaining heat medium flows through the bypass 27a and the bypass 27b, bypassing the use-side heat exchanger 26a and the use-side heat exchanger 26b. The heat medium passing through the bypass 27a and the bypass 27b does not participate in heat exchange, but merges with the heat medium passing through the use-side heat exchanger 26a and the use-side heat exchanger 26b, passes through the flow path switching valve 23a and the flow path switching valve 23b, It flows into the first intermediate heat exchanger 15a, and is sucked into the first pump 21a.

Similarly, the cooled heat medium flows into the flow rate adjustment valves 25c to 25f. At this time, only the flow rate of the heat medium required to supply the air-conditioning load required by the air-conditioning target area flows into the use-side heat exchangers 26c-26f through the action of the flow rate regulating valves 25c-25f, and the rest of the heat medium passes through the bypass 27c. -27f flows by bypassing use side heat exchanger 26c-26f. The heat medium passing through the bypasses 27c-27f does not participate in heat exchange, but merges with the heat medium passing through the use-side heat exchangers 26c-26f, passes through the flow path switching valves 23c-23f, flows into the second intermediate heat exchanger 15b, and is then Inhale the second pump 21b.

During this period, the hot heat medium (the heat medium used for the heat energy load) and the cold heat medium (the heat medium used for the cold energy load) are transferred through the flow path switching valves 22a to 22f and the flow path switching valves 23a to 23f. Functionally, it flows into the use-side heat exchanger 26a and the use-side heat exchanger 26b with the heating energy load, and the use-side heat exchanger 26c to the use-side heat exchanger 26f with the cooling energy load without mixing. In addition, by controlling and maintaining the temperature difference between the third temperature sensor 33 and the fourth temperature sensor 34 at a target value, the air-conditioning load required for an air-conditioning target area such as a room can be supplied.

[Main heating operation mode]

FIG. 15 is a refrigerant circuit diagram showing the refrigerant flow during the heating main operation mode of the air-conditioning apparatus 200 . In FIG. 15 , the heating main operation mode will be described by taking, as an example, a case where heating loads are generated in use-side heat exchangers 26a to 26d and cooling loads are generated in use-side heat exchangers 26e and 26f. In addition, in FIG. 15 , pipes indicated by thick lines are pipes through which refrigerant (heat source side refrigerant and heat medium) circulates. In addition, 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 dotted line arrow.

In the heating main operation mode shown in FIG. 15, in the heat source device 101, the three-way valve 104a is switched so that the heat source side refrigerant discharged from the compressor 110 flows into the first intermediate heat exchanger 15a, and the three-way valve 104b is switched. , the heat source side refrigerant passing through the heat source side heat exchanger 105 is sucked into the compressor 110, and the two-way valves 107a to 107c are opened. In the relay unit 103, the first pump 21a and the second pump 21b are driven, the stop valve 24 is opened, and the heat medium is exchanged between the first intermediate heat exchanger 15a and the use-side heat exchangers 26a to 26d, and in the second intermediate heat exchanger. The heat exchanger 15b circulates between the use-side heat exchanger 26e and the use-side heat exchanger 26f. In this state, the operation of the compressor 110 is started.

First, the flow of refrigerant on the heat source side of the refrigeration cycle will be described.

The low-temperature, low-pressure refrigerant is compressed by the compressor 110 to become a high-temperature, high-pressure gas refrigerant, and then discharged. The high-temperature, high-pressure gas refrigerant discharged from the compressor 110 flows out of the heat source device 101 through the three-way valve 104a and the two-way valve 107b, and flows into the relay unit 103 through the refrigerant pipe 108b. The high-temperature, high-pressure gas refrigerant flowing into the first intermediate heat exchanger 15a is condensed and liquefied while dissipating heat to the heat medium circulating in the heat medium circuit, and becomes a high-pressure liquid refrigerant. The refrigerant flowing out of the first intermediate heat exchanger 15a passes through the fully opened expansion valve 203a, and then is divided into a refrigerant returning to the heat source device 101 through the refrigerant pipe 108a and a refrigerant flowing into the second intermediate heat exchanger 15b.

The refrigerant flowing into the second intermediate heat exchanger 15b expands at the expansion valve 203b, becomes a low-temperature, low-pressure two-phase refrigerant, and then flows into the second intermediate heat exchanger 15b, which acts as an evaporator. The circulating heat medium absorbs heat, and turns the heat medium into a low-temperature, low-pressure gas refrigerant while cooling the heat medium. The gas refrigerant flowing out of the second intermediate heat exchanger 15b flows out of the relay unit 103 through the two-way valve 205b, and flows into the heat source device 101 through the refrigerant pipe 108c.

On the other hand, the refrigerant returning to the heat source device 101 through the refrigerant pipe 108a is decompressed by the expansion valve 106 to become a gas-liquid two-phase refrigerant, and flows into the heat source side heat exchanger 105 functioning as an evaporator. Then, the refrigerant that has flowed into the heat source side heat exchanger 105 absorbs heat from the outdoor air in the heat source side heat exchanger 105 to become a low-temperature, low-pressure gas refrigerant. The gas refrigerant passes through the three-way valve 104b, merges with the low-pressure gas refrigerant flowing into the heat source device 101 through the refrigerant pipe 108c, and is sucked into the compressor 110 again.

Next, the flow of the heat medium in the heat medium circulation circuit will be described.

In the heating main operation mode, since both the first pump 21a and the second pump 21b are driven, the heat medium circulates through both the piping 5a and the piping 5b. The heat medium heated by the heat source side refrigerant in the first intermediate heat exchanger 15a flows through the pipe 5a by the first pump 21a. In addition, the heat medium cooled by the heat source side refrigerant in the second intermediate heat exchanger 15b flows through the pipe 5b by the second pump 21b.

The heat medium that has been pressurized by the first pump 21a and flowed out passes through the flow path switching valves 22a to 22d, passes through the shutoff valves 24a to 24d, and flows into the use side heat exchangers 26a to 26d. Then, the use-side heat exchangers 26a to 26d dissipate heat to the indoor air, thereby supplying heat to an air-conditioning target area such as a room where the indoor unit 102 is installed. In addition, the heat medium that is pressurized and flowed out by the second pump 21b passes through the flow path switching valve 22e and the flow path switching valve 22f, passes through the stop valve 24e and the stop valve 24f, and flows into the use-side heat exchanger 26e and the use-side heat exchanger. device 26f. Then, the use-side heat exchanger 26e and the use-side heat exchanger 26f absorb heat from the indoor air to cool an air-conditioning target area such as a room where the indoor unit 102 is installed.

The heat medium flowing out from the use side heat exchangers 26a to 26d flows into the flow rate adjustment valves 25a to 25d. At this time, only the flow rate of heat medium required to supply the air-conditioning load required by the air-conditioning target area such as indoors flows into the use-side heat exchangers 26a-26d by virtue of the flow rate regulating valves 25a-25d, and the rest of the heat medium passes through the bypass. The passages 27a to 27d flow by bypassing the use side heat exchangers 26a to 26d. The heat medium passing through the bypass paths 27a-27d does not participate in heat exchange, but joins the heat medium passing through the use-side heat exchangers 26a-26d, passes through the flow path switching valves 23a-23d, flows into the first intermediate heat exchanger 15a, and then flows into the first intermediate heat exchanger 15a. It is sucked into the first pump 21a.

Similarly, the heat medium flowing out from the use-side heat exchanger 26e and the use-side heat exchanger 26f flows into the flow rate regulating valve 25e and the flow rate regulating valve 25f. At this time, only the heat medium of the flow rate required to supply the air-conditioning load required for the air-conditioning target area such as indoors flows into the use-side heat exchanger 26e and the use-side heat exchanger by the action of the flow rate adjustment valve 25e and the flow rate adjustment valve 25f. 26f, and the remaining heat medium flows through the bypass 27e and the bypass 27f, bypassing the use-side heat exchanger 26e and the use-side heat exchanger 26f. The heat medium passing through the bypass 27e and the bypass 27f does not participate in heat exchange, but merges with the heat medium that has passed through the use-side heat exchanger 26e and the use-side heat exchanger 26f, and then passes through the flow path switching valve 23e and the flow path switching valve 23f , flows into the second intermediate heat exchanger 15b, and is sucked into the second pump 21b.

During this period, the hot heat medium and the cold heat medium flow into the use-side heat exchanger with thermal energy load through the action of the flow path switching valve 22 (flow path switching valves 22a to 22f) and the flow path switching valves 23a to 23f. 26a to 26d, the use-side heat exchanger 26e and the use-side heat exchanger 26f with cooling energy load are not mixed. In addition, by controlling and maintaining the temperature difference between the third temperature sensor 33 and the fourth temperature sensor 34 at a target value, the air-conditioning load required for an air-conditioning target area such as a room can be supplied.

As mentioned above, the relay unit 103 is a separate frame from the heat source device 101 and the indoor unit 102, so the relay unit 103 can be arranged in a position different from them. As shown in FIG. 1, if the relay unit 103 If it is installed in the non-residential space 50, the refrigerant on the heat source side can be separated from the heat medium, preventing the refrigerant on the heat source side from flowing into the residential space 7, and improving the safety and reliability of the air conditioning device 200.

In the first intermediate heat exchanger 15a on the heating side, the temperature of the heat medium at the outlet of the first intermediate heat exchanger 15a detected by the first temperature sensor 31a is not higher than the first intermediate temperature detected by the second temperature sensor 32a. The temperature of the heat medium at the inlet of the heat exchanger 15a and the heating amount of the superheated gas region of the heat source side refrigerant are small. Therefore, the temperature of the heat medium at the outlet of the first intermediate heat exchanger 15 a is limited by the condensation temperature obtained approximately from the saturation temperature of the first pressure sensor 36 . In addition, in the second intermediate heat exchanger 15b on the cooling side, the temperature of the heat medium at the outlet of the second intermediate heat exchanger 15b detected by the first temperature sensor 31b is not lower than the temperature of the second intermediate heat exchanger 15b detected by the second temperature sensor 32b. 2The temperature of the heat medium at the inlet of the intermediate heat exchanger 15b.

Therefore, in the air-conditioning apparatus 200, by changing the condensing temperature or the evaporating temperature on the refrigeration cycle side, it is possible to effectively respond to an increase or decrease in heat load on the secondary side (use side). Therefore, it is desirable to change the control target value of the condensation temperature and/or the evaporation temperature of the refrigeration cycle stored in the control device (not shown) according to the magnitude of the heat load on the use side. In this way, it is possible to easily follow changes in the magnitude of the thermal load on the usage side.

The control device connected to the second relay unit 3b performs grasping of the change of the thermal load on the usage side. On the other hand, the control target values of the condensation temperature and the evaporation temperature are stored in a control device connected to the heat source device 101 including the compressor 110 and the heat source side heat exchanger 105 . For this reason, connect the signal line between the control device connected with the 2nd relay unit 3b and the control device connected with the heat source device 101, utilize communication, send the control target value of condensing temperature or/and evaporating temperature, change and store in and The control target value of the condensation temperature or/and evaporation temperature in the control device connected to the heat source device 101 . In addition, a deviation value of the control target value may be communicated to change the control target value.

By performing such control, it is possible to appropriately respond to changes in the heat load on the usage side. That is, the control device can control the driving frequency of the compressor 110 so as to reduce the workload of the compressor 110 when the heat load on the usage side is reduced. Therefore, more energy-saving operation can be performed in the air-conditioning apparatus 200 . In addition, the control device connected to the second relay unit 3b and the control device connected to the heat source device 101 may be implemented by one control device.

In addition, in the air-conditioning apparatus 200 of Embodiment 2, the expansion tank 60 described in Embodiment 1 is connected via the heating-side expansion tank connection port 42 and the cooling-side expansion tank connection port 43 as shown in FIG. 11 . In addition, in Embodiment 2, the case where the three-way valve was used was demonstrated as an example, but it is not limited to this, For example, it is also possible to combine a four-way valve, a solenoid valve, etc., and to have the same function. In addition, usable heat source side refrigerants and heat mediums are also the same as those described in Embodiment 1.

Claims (10)

1. conditioner is characterized in that having:

At least one intermediate heat exchanger, this intermediate heat exchanger carries out heat exchange with cold-producing medium with the thermal medium different with above-mentioned cold-producing medium;

Freeze cycle loop, this freeze cycle loop connect the refrigerant side stream of compressor, outdoor heat converter, at least one expansion valve and above-mentioned intermediate heat exchanger via the pipe arrangement of above-mentioned cold-producing medium circulation; And

The thermal medium closed circuit, this thermal medium closed circuit connects thermal medium effluent road, the pump of above-mentioned intermediate heat exchanger and uses the side heat exchanger via the pipe arrangement of above-mentioned medium passing;

Above-mentioned compressor and above-mentioned outdoor heat converter are housed in the off-premises station;

Above-mentioned intermediate heat exchanger and said pump are housed in the TU Trunk Unit;

Above-mentioned use side heat exchanger is housed in the indoor set;

At above-mentioned thermal medium closed circuit, be connected with the expansion absorption device of the Volume Changes that is used to absorb above-mentioned thermal medium.

2. conditioner as claimed in claim 1 is characterized in that,

As above-mentioned intermediate heat exchanger, have the intermediate heat exchanger and the intermediate heat exchanger that is used for the cooling of above-mentioned thermal medium of the heating that is used for above-mentioned thermal medium.

3. conditioner as claimed in claim 1 or 2 is characterized in that,

Above-mentioned TU Trunk Unit is divided into the 1st TU Trunk Unit and the 2nd TU Trunk Unit;

The gas-liquid separator that is used for cold-producing medium is separated into gas and liquid is housed in above-mentioned the 1st TU Trunk Unit;

Above-mentioned intermediate heat exchanger and said pump are housed in above-mentioned the 2nd TU Trunk Unit.

4. conditioner as claimed in claim 3 is characterized in that,

Connect above-mentioned off-premises station and above-mentioned the 1st TU Trunk Unit by 2 pipe arrangements as the reciprocal path of cold-producing medium;

Connect above-mentioned the 2nd TU Trunk Unit and each above-mentioned indoor set by 2 pipe arrangements as the reciprocal path of thermal medium.

5. conditioner as claimed in claim 1 or 2 is characterized in that,

Connect above-mentioned off-premises station and above-mentioned TU Trunk Unit by at least 3 pipe arrangements as the reciprocal path of cold-producing medium;

Connect above-mentioned TU Trunk Unit and each above-mentioned indoor set by 2 pipe arrangements as the reciprocal path of thermal medium.

6. as each described conditioner in the claim 1 to 5, it is characterized in that, to be connected above-mentioned expansion absorption device with mode that the attraction side of said pump is communicated with.

7. as each described conditioner in the claim 1 to 6, it is characterized in that above-mentioned expansion absorption device is an expansion tank.

8. conditioner as claimed in claim 7 is characterized in that, the volume of above-mentioned expansion tank is below 5 liters.

9. as claim 7 or 8 described conditioners, it is characterized in that be configured in than above-mentioned indoor set in the conditioner of upside at above-mentioned expansion tank, the difference in height of above-mentioned expansion tank and above-mentioned indoor set is below 10m.

10. as each described conditioner in the claim 1 to 9, it is characterized in that the pressure of the thermal medium when above-mentioned thermal medium closed circuit is supplied with is set to 100kPaG.

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