GB2573224A

GB2573224A - Air conditioner

Info

Publication number: GB2573224A
Application number: GB1909669.2A
Authority: GB
Inventors: okochi Kazuki; Motomura Yuji; Morimoto Osamu
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2017-02-06
Filing date: 2017-02-06
Publication date: 2019-10-30
Anticipated expiration: 2037-02-06
Also published as: GB2573224B; GB201909669D0; WO2018142607A1; JPWO2018142607A1

Abstract

An air conditioner according to the present invention is configured with a heat-source-side refrigerant circulation circuit through which a heat-source-side refrigerant circulates and a heat medium circulation circuit through which a heat medium circulates, wherein: a compressor, a first refrigerant flow path switching device, and a heat-source-side heat exchanger are housed in an outdoor unit; an inter-heat medium heat exchanger and a throttle device are housed in a heat exchange unit; and a use-side heat exchanger is housed in an indoor unit, the air conditioner being provided with a refrigerant-circuit-side flow path switching unit that is connected through piping between the outdoor unit and the heat exchange unit, that is removably installed, and that has a second refrigerant flow path switching device for switching the circulation path of the heat-source-side refrigerant in the heat-source-side refrigerant circulation circuit, and provided with a heat-medium-circuit-side switching unit that is connected through piping between the heat exchange unit and the indoor unit, that is removably installed, and that has a heat medium flow path switching device for switching the circulation path of the heat medium in the heat medium circulation circuit.

Description

DESCRIPTION

Title of Invention

AIR-CONDITIONING DEVICE

Technical Field [0001]

The present invention relates to an air-conditioning device applied, for example, to variable refrigerant flow systems and other similar apparatuses. Background Art [0002]

For example, there is an air-conditioning device that includes a refrigeration cycle circuit (refrigerant cycle circuit) configured to circulate heat source side refrigerant by connecting an outdoor unit and relay unit by pipes, the circulated heat source side refrigerant, and a heat medium cycle circuit configured to circulate a heat medium (indoor side refrigerant) by connecting the relay unit and indoor units by pipes. In the heat source side refrigerant cycle circuit, the outdoor unit and relay unit are connected by pipes, and in the heat medium cycle circuit, the relay unit and plural indoor units are connected by pipes. Then, through heat exchange between the heat source side refrigerant and the heat medium in a heat medium heat exchanger of the relay unit, the heat medium supplies heating energy or cooling energy to an indoor side for air-conditioning. Here, for application, for example, to variable refrigerant flow systems and other similar apparatuses, an air-conditioning device designed to save energy by reducing heat medium transport power has been proposed (see, for example, Patent Literature 1). The reason why the air-conditioning device includes two cycle circuits is to use water or other refrigerant that will not adversely affect the health of users in the building as a heat medium circulating on an indoor side.

Citation List

Patent Literature [0003]

Patent Literature 1: International Publication No. WO 2010/049998 Summary of Invention Technical Problem [0004]

Here, the air-conditioning device of Patent Literature 1 described above includes a heat medium side switching device in the relay unit to switch flow paths of the heat medium. This configuration limits the number of indoor units in the heat medium circuit, making expansion difficult.

[0005]

Also, the air-conditioning device of Patent Literature 1 described above is capable of cooling and heating mixed operation, whereby some of the plural indoor units perform cooling while part or all of the remaining indoor units perform heating. Here, from an energy saving (such as described above), safety, or other perspective, an air-conditioning device such as described in Patent Literature 1 may be required, for example, for facilities that do not need cooling and heating mixed operation to be performed.

[0006]

However, if an air-conditioning device such as described in Patent Literature 1 is installed as it is in facilities that do not need cooling and heating mixed operation to be performed, some of components included in the air-conditioning device will be unnecessary.

[0007]

The present invention has been made to solve the above problem and has an object to provide an air-conditioning device having a circuit configuration that is readily changed depending on application.

Solution to Problem [0008]

An air-conditioning device according to an embodiment of the present invention includes a heat source side refrigerant cycle circuit configured to circulate heat source side refrigerant, the heat source side refrigerant cycle circuit including a compressor configured to compress the heat source side refrigerant, a first refrigerant flow switching device configured to switch circulation paths of the heat source side refrigerant, a heat source side heat exchanger configured to make the heat source side refrigerant exchange heat, an expansion device configured to adjust pressure of the heat source side refrigerant, and an intermediate heat exchanger configured to exchange heat between the heat source side refrigerant and a heat medium different from the heat source side refrigerant, the compressor, the first refrigerant flow switching device, the heat source side heat exchanger, the expansion device, and the intermediate heat exchanger being connected by pipes; and a heat medium cycle circuit configured to circulate the heat medium, the heat medium cycle circuit including the intermediate heat exchanger, a pump configured to pressurize the heat medium, and a use side heat exchanger configured to exchange heat between the heat medium and air in an air-conditioned space, the intermediate heat exchanger, the pump, and the use side heat exchanger being connected by pipes. The compressor, the first refrigerant flow switching device, and the heat source side heat exchanger are housed in an outdoor unit, the intermediate heat exchanger and the expansion device are housed in a heat exchange unit, and the use side heat exchanger is housed in an indoor unit. The air-conditioning device further includes a refrigerant circuit side flow switching unit connected between the outdoor unit and the heat exchange unit by pipes, installed in such a manner that the refrigerant circuit side flow switching unit is allowed to be removed, and provided with a second refrigerant flow switching device configured to switch circulation paths of the heat source side refrigerant in the heat source side refrigerant cycle circuit; and a heat medium circuit side flow switching unit connected between the heat exchange unit and the indoor unit by pipes, installed in such a manner that the heat medium circuit side flow switching unit is allowed to be removed, and provided with a heat medium flow switching device configured to switch circulation paths of the heat medium in the heat medium cycle circuit.

Advantageous Effects of Invention [0009]

According to an embodiment of the present invention, in the air-conditioning device that implements air-conditioning by being provided with the heat source side refrigerant cycle circuit and the heat medium cycle circuit, as the refrigerant circuit side flow switching unit configured to switch the circulation paths of the heat source side refrigerant between the outdoor unit and the heat exchange unit and the heat medium circuit side flow switching unit configured to switch the circulation paths of the heat medium between the heat exchange unit and the indoor unit are installed, in such a manner that the refrigerant circuit side flow switching unit and the heat medium circuit side flow switching unit are each allowed to be removed, the circuit configuration and other features can be changed readily depending on necessary operating functions and other factors.

Brief Description of Drawings [0010] [Fig. 1] Fig. 1 is a diagram showing an outline of an installation example of an air-conditioning device according to Embodiment 1 of the present invention.

[Fig. 2] Fig. 2 is a diagram showing a configuration example of the air-conditioning device according to Embodiment 1 of the present invention.

[Fig. 3] Fig. 3 is a diagram showing flows of refrigerant in heating only operation mode of the air-conditioning device according to Embodiment 1 of the present invention.

[Fig. 4] Fig. 4 is a diagram showing flows of refrigerant in heating main operation mode of the air-conditioning device according to Embodiment 1 of the present invention.

[Fig. 5] Fig. 5 is a diagram showing flows of refrigerant in cooling only operation mode of the air-conditioning device according to Embodiment 1 of the present invention.

[Fig. 6] Fig. 6 is a diagram showing flows of refrigerant in cooling main operation mode of the air-conditioning device according to Embodiment 1 of the present invention.

[Fig. 7] Fig. 7 is a diagram illustrating another form of the air-conditioning device according to Embodiment 1 of the present invention.

[Fig. 8] Fig. 8 is a diagram showing flows of refrigerant in heating operation mode of the other form of the air-conditioning device according to Embodiment 1 of the present invention.

[Fig. 9] Fig. 9 is a diagram showing flows of refrigerant in cooling operation mode of the other form of the air-conditioning device according to Embodiment 1 of the present invention.

[Fig. 10] Fig. 10 is a diagram showing a configuration of another air-conditioning device according to Embodiment 1 of the present invention.

[Fig. 11] Fig. 11 is a diagram showing a configuration of an air-conditioning device according to Embodiment 2 of the present invention.

[Fig. 12] Fig. 12 is a diagram showing a configuration of another air-conditioning device according to Embodiment 2 of the present invention.

Description of Embodiments [0011]

Air-conditioning devices according to embodiments of the present invention will be described below with reference to the drawings. In the following drawings, the same components or equivalent components are denoted by the same reference signs and are common throughout the entire text of the embodiments described below. Also, in the drawings, components may not be shown in their true size relations. The forms of the components described throughout the entire text of the specification are strictly exemplary, and the components are not limited to the forms described herein. In particular, combinations of components are not limited to those described in any of the embodiments, and components described in one embodiment may be applied to another embodiment. Also, magnitudes of pressures and temperatures are not determined in relation to absolute values, in particular, but are determined on a relative basis depending on conditions, operations, and other factors of components. Besides, plural units of the same components distinguished by subscripts may be described without the subscripts when there is no need to distinguish or identify the units from one another.

[0012]

Embodiment 1

Fig. 1 is a diagram showing an outline of an installation example of an air-conditioning device according to Embodiment 1 of the present invention. An installation example of the air-conditioning device according to Embodiment 1 will be described with reference to Fig. 1. The air-conditioning device includes a refrigerant cycle circuit configured to circulate heat source side refrigerant and a heat medium cycle circuit configured to circulate a heat medium such as water, and cools or heats rooms. Each indoor unit 3 allows cooling or heating to be selected freely.

[0013]

In Fig. 1, the air-conditioning device according to Embodiment 1 includes one outdoor unit 1 serving as a heat source device, plural indoor units 3, a relay unit 2, a heat medium circuit side flow switching unit 23, and a heat medium adjustment unit 24. As described later, the relay unit 2 includes a refrigerant circuit side flow switching unit 21 and a heat exchange unit 22 including heat medium heat exchangers 25 and is configured to relay heat transfer between heat source side refrigerant circulating through the refrigerant cycle circuit and a heat medium circulating through the heat medium cycle circuit. The outdoor unit 1 and relay unit 2 are connected with each other via refrigerant pipes 4 serving as flow paths for the heat source side refrigerant. Also, the relay unit 2 is connected to each of the indoor units 3 via heat medium pipes 5 serving as flow paths for the heat medium.

[0014]

Here, plural relay units 2 can be connected to one outdoor unit 1. Also, for example, plural heat medium circuit side flow switching units 23 and heat medium adjustment units 24 can be connected to the relay unit 2. Besides, the refrigerant circuit side flow switching unit 21 and heat exchange unit 22 are combined to make up the relay unit 2 here, but the refrigerant circuit side flow switching unit 21 and heat exchange unit 22 may be provided as separate units.

[0015]

Examples of refrigerants available for use as the heat source side refrigerant circulating through the refrigerant cycle circuit include single refrigerants such as R-22 and R-134a, near-azeotropic refrigerant mixtures such as R-410Aand R-404A, non-azeotropic refrigerant mixtures such as R-407C, refrigerants such as CF3CF=CH2 having a double bond in their chemical formulae and having a relatively low global warming potential or a combination of the refrigerants, and natural refrigerants such as CO2 and propane.

[0016]

Examples of fluids available for use as the heat medium circulating through the heat medium cycle circuit include brine (antifreeze solution) or water, a mixture of brine and water, and a mixture of water and an additive with a high anticorrosive effect. In this manner, the air-conditioning device of Embodiment 1 can use a safe fluid for a heat medium. Consequently, the air-conditioning device according to Embodiment 1 is safe even if, for example, the heat medium leaks into indoor space 7 through the indoor unit 3.

[0017]

Next, operation of the air-conditioning device will be described with reference to Fig. 1. The outdoor unit 1 circulates the heat source side refrigerant between the outdoor unit 1 and relay unit 2 through the refrigerant pipes 4. In so doing, the heat source side refrigerant exchanges heat with the heat medium in the heat medium heat exchangers 25 in the relay unit 2 described later. The heat medium is heated or cooled through the heat exchange.

[0018]

The heat medium heated or cooled in the relay unit 2 is circulated between the relay unit 2 and the indoor units 3 through the heat medium pipes 5 by pumps 31 described later. In so doing, the heat medium exchanges heat with air in a use side heat exchanger 35 of each of the indoor units 3 described later. After exchanging heat with the heat medium, the air is used to heat or cool the indoor space 7.

[0019]

Fig. 2 is a diagram showing a configuration example of the air-conditioning device according to Embodiment 1 of the present invention. A configuration of the air-conditioning device will be described with reference to Fig. 2. As described above, the outdoor unit 1 and relay unit 2 are connected with each other via the refrigerant pipes 4. Also, the relay unit 2 is connected to each of the indoor units 3 via the heat medium pipes 5.

[0020] [Outdoor unit 1]

The outdoor unit 1 has a compressor 10, a first refrigerant flow switching device 11, a heat source side heat exchanger 12, and an accumulator 19 in a housing. The compressor 10, first refrigerant flow switching device 11, heat source side heat exchanger 12, and accumulator 19 are installed by being connected by the refrigerant pipes 4. The compressor 10 suctions and compresses the heat source side refrigerant and discharges the refrigerant in a high-temperature, high-pressure state. Here, the compressor 10 can be, for example, a capacity-controllable inverter compressor. Also, the first refrigerant flow switching device 11, such as a four-way valve, switches between a flow of heat source side refrigerant in the refrigerant cycle circuit in heating operation mode (heating only operation mode or heating main operation mode) and a flow of heat source side refrigerant in the refrigerant cycle circuit in cooling operation mode (cooling only operation mode or cooling main operation mode) as described later.

[0021]

The heat source side heat exchanger 12 exchanges heat, for example, between air supplied from an outdoor side fan (not shown) and the heat source side refrigerant. In heating operation mode, the heat source side heat exchanger 12 serves as an evaporator and makes the heat source side refrigerant receive heat.

On the other hand, in cooling operation mode, the heat source side heat exchanger 12 serves as a condenser or radiator and makes the heat source side refrigerant reject heat. The accumulator 19 is provided close to a suction port of the compressor 10. The accumulator 19 accumulates, for example, surplus refrigerant generated during transitional periods and other periods in which operation changes to cause differences between heating operation mode and cooling operation mode.

[0022]

Also, the outdoor unit 1 includes a first connecting pipe 4a, a second connecting pipe 4b, and check valves 13a to 13d. Installation of the first connecting pipe 4a, second connecting pipe 4b, and check valves 13a to 13d makes a portion of the refrigerant pipes 4 through which the heat source side refrigerant flows from the outdoor unit 1 to the relay unit 2 always the same and another portion of the refrigerant pipes 4 through which the heat source side refrigerant flows from the relay unit 2 to the outdoor unit 1 always the same, regardless of operation mode. The first connecting pipe 4a, second connecting pipe 4b, and check valves 13a to 13d are not essential components of the air-conditioning device of Embodiment 1, and thus can be omitted.

[0023] [Indoor unit 3]

The indoor units 3 each have the use side heat exchanger 35 in the housing. The use side heat exchanger 35 is connected with the heat medium pipes 5 to pass the heat medium through the use side heat exchanger 35. The use side heat exchanger 35 exchanges heat between the air supplied from an indoor side fan (not shown) and the heat medium. When the heat medium passing through the use side heat exchanger 35 is hot, the air is heated, heating the indoor space 7. When the heat medium passing through the use side heat exchanger 35 is cold, the air is cooled, cooling the indoor space 7.

[0024]

Here, Fig. 2 shows an example in which the four indoor units 3 and the relay unit 2 are connected with each other. An indoor unit 3a, indoor unit 3b, indoor unit 3c, and indoor unit 3d are illustrated starting from top of Fig. 2. The use side heat exchangers 35, namely a use side heat exchanger 35a, use side heat exchanger 35b, use side heat exchanger 35c, and use side heat exchanger 35d corresponding to the indoor units 3a to 3d, are illustrated starting from top of Fig. 2. Here, as with Fig. 1, the number of the indoor units 3 connected to the relay unit 2 is not limited to four, which is illustrated in Fig. 2.

[0025] [Relay unit 2]

Next, a configuration of the relay unit 2 will be described. As described above, the relay unit 2 includes the refrigerant circuit side flow switching unit 21 and heat exchange unit 22. The refrigerant circuit side flow switching unit 21 is a modularized device configured to switch the flow paths of the heat source side refrigerant passing through the relay unit 2. The refrigerant circuit side flow switching unit 21 includes open-close devices 27 and 29 as well as second refrigerant flow switching devices 28 (second refrigerant flow switching devices 28a and 28b). The open-close devices 27 and 29 are, for example, devices such as solenoid valves capable of opening and closing action depending on whether or not the devices are energized and configured to switch refrigerant flow paths in the refrigerant cycle circuit by being subjected to open-close control depending on operation mode. The open-close device 27 is provided in the refrigerant pipes 4 at a flow inlet of the heat source side refrigerant in the relay unit 2. On the other hand, the open-close device 29 is provided in a pipe (bypass pipe) connecting the refrigerant pipes 4 at the flow inlet of the heat source side refrigerant with the refrigerant pipes 4 at a flow outlet of the relay unit 2. The two second refrigerant flow switching devices 28 (second refrigerant flow switching devices 28a and 28b) are, for example, four-way valves. The second refrigerant flow switching devices 28 switch the flow paths of heat source side refrigerant depending on operation mode in such a manner that the heat medium heat exchangers 25 can be used as condensers or evaporators. The second refrigerant flow switching device 28a is provided downstream of the heat medium heat exchanger 25a along the flow of heat source side refrigerant in cooling operation mode. On the other hand, the second refrigerant flow switching device 28b is provided downstream of the heat medium heat exchanger 25b along the flow of heat source side refrigerant in cooling only operation mode.

[0026]

The heat exchange unit 22 includes components involved in heat transfer between the heat source side refrigerant circulating through the refrigerant cycle circuit and the heat medium circulating through the heat medium cycle circuit. The heat exchange unit 22 includes two heat medium heat exchangers 25 (heat medium heat exchanger 25a and heat medium heat exchanger 25b), two expansion devices 26 (expansion device 26a and expansion device 26b), and two pumps 31 (pump 31a and pump 31b).

[0027]

The heat medium heat exchangers 25 (heat medium heat exchanger 25a and heat medium heat exchanger 25b) exchange heat between the heat source side refrigerant and heat medium and thereby transfer heat from the heat source side refrigerant to the heat medium. To heat the heat medium, the heat medium heat exchangers 25 serve as condensers or radiators and make the heat source side refrigerant reject heat. On the other hand, to cool the heat medium, the heat medium heat exchangers 25 serve as evaporators and make the heat source side refrigerant receive heat.

[0028]

Here, the heat medium heat exchanger 25a is provided between the expansion device 26a and second refrigerant flow switching device 28a in the refrigerant cycle circuit. The heat medium heat exchanger 25a serves as an evaporator and cools the heat medium in cooling only operation mode and in cooling and heating mixed operation mode (cooling main operation mode or heating main operation mode). In heating only operation mode, the heat medium heat exchanger 25a serves as a condenser or radiator and heats the heat medium. On the other hand, the heat medium heat exchanger 25b is provided between the expansion device 26b and second refrigerant flow switching device 28b in the refrigerant cycle circuit. In heating only operation mode and cooling and heating mixed operation mode, the heat medium heat exchanger 25b serves as a condenser or radiator and heats the heat medium. In cooling only operation mode, the heat medium heat exchanger 25b serves as an evaporator and cools the heat medium.

[0029]

Also, the two expansion devices 26 (expansion device 26a and expansion device 26b) serve as pressure reducing valves and expansion valves and depressurize and expand the heat source side refrigerant. The expansion device 26a is provided upstream of the heat medium heat exchanger 25a along the flow of heat source side refrigerant in cooling operation mode. On the other hand, the expansion device 26b is provided upstream of the heat medium heat exchanger 25b along the flow of heat source side refrigerant during cooling operation. Here, advisably the expansion devices 26 are, for example, electronic expansion valves or other devices each capable of controlling an opening degree to any desired value and adjusting a flow rate of the heat source side refrigerant and other parameters of the heat source side refrigerant as desired.

[0030]

The two pumps 31 (pump 31a and pump 31b) suction and pressurize the heat medium and circulate the heat medium through the heat medium cycle circuit. The pump 31a is provided on the heat medium pipes 5 and between the heat medium heat exchanger 25a and second heat medium flow switching devices 33. The pump 31b is provided on the heat medium pipes 5 and between the heat medium heat exchanger 25b and the second heat medium flow switching devices 33. Here, advisably the pumps 31 are, for example, capacity-controllable pumps and capable of adjusting a flow rate of the heat medium depending on the magnitude of thermal loads of the indoor units 3.

[0031] [Heat medium circuit side flow switching unit 23]

The heat medium circuit side flow switching unit 23 is a modularized device configured to switch the flow paths of the heat medium passing through the relay unit 2. The heat medium circuit side flow switching unit 23 of Embodiment 1 includes four first heat medium flow switching devices 32 (first heat medium flow switching device 32a to first heat medium flow switching device 32d) and the four second heat medium flow switching devices 33 (second heat medium flow switching device 33a to second heat medium flow switching device 33d).

[0032]

The first heat medium flow switching devices 32 are, for example, three-way valves. The first heat medium flow switching devices 32 switch the flow paths of the heat medium in the heat medium cycle circuit in conjunction with the second heat medium flow switching devices 33. The first heat medium flow switching devices 32 are connected with the respective use side heat exchangers 35 of the indoor units 3 via heat medium flow control devices 34 and are connected with the heat medium heat exchanger 25a and the heat medium heat exchanger 25b. Also, the first heat medium flow switching devices 32 are provided to heat medium outlets of the use side heat exchangers 35. The first heat medium flow switching devices 32 are switched in such a manner that the heat medium flowing out of the indoor units 3 flows to the heat medium heat exchanger 25a or heat medium heat exchanger 25b. Here, the first heat medium flow switching devices 32 are installed for the respective indoor units 3. The four first heat medium flow switching devices 32, namely the first heat medium flow switching device 32a, first heat medium flow switching device 32b, first heat medium flow switching device 32c, and first heat medium flow switching device 32d for the respective indoor units 3, are illustrated starting from top of Fig. 2. Also, the flow path switching by the first heat medium flow switching devices 32 includes not only alternative switching between the heat medium heat exchanger 25a and heat medium heat exchanger 25b, but also flow ratio switching.

[0033]

The second heat medium flow switching devices 33 are, for example, three-way valves. The second heat medium flow switching devices 33 switch the flow paths of the heat medium in the heat medium cycle circuit in conjunction with the first heat medium flow switching devices 32. The second heat medium flow switching devices 33 are connected with the heat medium heat exchanger 25a, heat medium heat exchanger 25b, and the respective use side heat exchangers 35 of the indoor units 3 and are provided to heat medium inlets of the use side heat exchangers 35. The second heat medium flow switching devices 33 are switched in such a manner that the heat medium flowing out of the heat medium heat exchangers 25a and 25b flows into the indoor units 3. Here, the second heat medium flow switching devices 33 are installed for the respective indoor units 3. The four second heat medium flow switching devices 33, namely the second heat medium flow switching device 33a, second heat medium flow switching device 33b, second heat medium flow switching device 33c, and second heat medium flow switching device 33d for the respective indoor units 3, are illustrated starting from top of Fig. 2. Also, the flow path switching by the second heat medium flow switching devices 33 includes not only alternatively switching the inflow of heat medium from the heat medium heat exchanger 25a or heat medium heat exchanger 25b, but also inflow ratio switching.

[0034] [Heat medium adjustment unit 24]

The heat medium adjustment unit 24 is a modularized device configured to adjust a flow rate of the heat medium passing through the relay unit 2 and flowing in and out of the indoor units 3. The heat medium adjustment unit 24 of Embodiment 1 includes four heat medium flow control devices 34 (heat medium flow control device 34a to heat medium flow control device 34d).

[0035]

The heat medium flow control devices 34 are two-way valves or other devices each having a controllable opening area. The heat medium flow control devices 34 control flow rates of the heat medium flowing through the heat medium pipes 5. The heat medium flow control devices 34 are connected between the respective use side heat exchangers 35 and first heat medium flow switching devices 32. The heat medium flow control devices 34 adjust a flow rate of the heat medium passing through the indoor units 3 depending on temperatures of the heat medium flowing into the indoor units 3 and temperatures of the heat medium flowing out of the indoor units 3 and thereby allow the use side heat exchangers 35 to exchange heat depending on indoor load. Here, heat medium flow control devices 34 are installed for the respective indoor units 3. The heat medium flow control device 34a, heat medium flow control device 34b, heat medium flow control device 34c, and heat medium flow control device 34d for the respective indoor units 3 are illustrated starting from top of Fig. 2. Also, when no load is required by one of the indoor units 3 such as when the one of the indoor units 3 is in a stopped state or a thermo-off state, the corresponding one of the heat medium flow control devices 34 can stop heat medium supply to the one of the indoor units 3 by closing itself fully. Furthermore, the heat medium flow control devices 34 may be provided between the respective use side heat exchangers 35 and second heat medium flow switching devices 33. When the first heat medium flow switching devices 32 or second heat medium flow switching devices 33 can take over functions of the heat medium flow control devices 34, installation of the heat medium flow control devices 34 may be omitted.

[0036]

Also, the relay unit 2 is provided with two temperature sensors 40 (temperature sensor 40a and temperature sensor 40b). Information obtained (information on temperature measured) by the temperature sensors 40 is sent to a controller (not shown) configured to centrally control operation of the air-conditioning device and is used to control driving frequency of the compressor 10, rotation speed of a non-i I lustrated fan, switching of the first refrigerant flow switching device 11, driving frequencies of the pumps 31, switching of the second refrigerant flow switching devices 28, switching of the heat medium flow paths, adjustment of heat medium flow rates of the indoor units 3, and other parameters. The two temperature sensors 40 are designed to measure temperatures of the heat medium flowing out of the heat medium heat exchangers 25, that is, temperatures of the heat medium at outlets of the heat medium heat exchangers 25, and are advisably thermistors or other similar devices. The temperature sensor 40a is provided on the heat medium pipes 5 at an inlet of the pump 31 a. The temperature sensor 40b is provided on the heat medium pipes 5 at an inlet of the pump 31 b.

[0037]

Fig. 3 is a diagram showing flows of refrigerant in heating only operation mode of the air-conditioning device according to Embodiment 1 of the present invention.

An example in which all the indoor units 3 are in heating mode will be described in Fig. 3. Here, in Fig. 3, the thick lines in the refrigerant cycle circuit represent portions of the refrigerant pipes 4 through which the heat source side refrigerant passes in heating only operation mode. Also, directions in which the heat source side refrigerant flows are represented by solid arrows and directions in which the heat medium flows are represented by dashed arrows.

[0038]

The compressor 10 compresses the heat source side refrigerant and discharges high-temperature, high-pressure gaseous heat source side refrigerant.

The discharged high-temperature, high-pressure refrigerant flows out of the outdoor unit 1 through the first refrigerant flow switching device 11 and check valve 13c and flows into the relay unit 2 through a portion of the refrigerant pipes 4 that is outside the outdoor unit 1. Here, the first refrigerant flow switching device 11 is switched in such a manner that the high-temperature, high-pressure gaseous refrigerant discharged from the compressor 10 flows out of the outdoor unit 1 without passing through the heat source side heat exchanger 12 in the outdoor unit 1.

[0039]

The gaseous heat source side refrigerant flowing into the relay unit 2 is branched and flows into the second refrigerant flow switching device 28a and second refrigerant flow switching device 28b. Here, the second refrigerant flow switching devices 28a and 28b are switched for heating. The open-close device 27 is closed. Flows of the gaseous heat source side refrigerant passing through the second refrigerant flow switching devices 28a and 28b, respectively, then pass through the heat medium heat exchangers 25a and 25b while exchanging heat with the heat medium. The heat source side refrigerant passing through the heat medium heat exchangers 25a and 25b becomes high-temperature, high-pressure liquid refrigerant. The heat source side refrigerant that has become high-temperature, high-pressure liquid refrigerant is depressurized by passing through the expansion devices 26a and 26b to become low-temperature, low-pressure two-phase gas-liquid refrigerant. The flows of low-temperature, low-pressure, two-phase gas-liquid, heat source side refrigerant passing through the expansion devices 26a and 26b join together and flow out of the relay unit 2. In so doing, the open-close device 29 is closed.

[0040]

After flowing out of the relay unit 2, the heat source side refrigerant passes through a portion of the refrigerant pipes 4 that is outside and flows into the outdoor unit 1. After flowing into the outdoor unit 1, the low-temperature, low-pressure, heat source side refrigerant passes through the check valve 13b and then through the heat source side heat exchanger 12. In so doing, the heat source side refrigerant exchanges heat with air in outdoor space 6 and becomes low-temperature, low-pressure, gaseous heat source side refrigerant. The heat source side refrigerant is suctioned into the compressor 10 by passing through the first refrigerant flow switching device 11 and accumulator 19.

[0041]

Next, flows of heat medium in heating only operation mode will be described.

As described above, the heat medium exchanges heat with high-temperature, high-pressure gaseous refrigerant in the heat medium heat exchangers 25a and 25b and becomes a high-temperature heat medium. The heat medium turned into the high-temperature heat medium in the heat medium heat exchangers 25a and 25b is transported to the indoor units 3 by the pumps 31a and 31b connected to the heat medium heat exchangers 25a and 25b, respectively. The transported heat medium passes through the second heat medium flow switching devices 33 of the heat medium circuit side flow switching unit 23 connected to the respective indoor units 3. Then, flow rates of the heat medium flowing into the indoor units 3 are adjusted by the respective heat medium flow control devices 34. In so doing, the second heat medium flow switching devices 33 adjust the opening degrees to intermediate opening degrees or opening degrees suitable for temperatures of the heat medium at heat medium flow outlets of the heat medium heat exchangers 25a and 25b in such a manner that the heat medium transported from both the heat medium heat exchangers 25a and 25b can be supplied to the heat medium flow control devices 34 and indoor units 3. The heat medium flowing into the indoor units 3 connected by the heat medium pipes 5 exchanges heat with indoor air in the indoor space 7 at the use side heat exchangers 35 to heat the indoor space 7. After exchanging heat at the use side heat exchangers 35, the heat medium is transported into the relay unit 2 through the heat medium pipes 5 and heat medium flow control devices 34. The transported heat medium flows into the heat medium heat exchangers 25a and 25b through the first heat medium flow switching devices 32 of the heat medium circuit side flow switching unit 23 and receives heat from the refrigerant by amounts corresponding to the heat supplied to the indoor space 7 at the indoor units 3. Then, the heat medium is transported to the pumps 31a and 31b again.

[0042]

Fig. 4 is a diagram showing flows of refrigerant in heating main operation mode of the air-conditioning device according to Embodiment 1 of the present invention. Here, in Fig. 4, the thick lines in the refrigerant cycle circuit represent portions of the refrigerant pipes 4 through which the heat source side refrigerant passes in heating only operation mode. Also, directions in which the heat source side refrigerant flows are represented by solid arrows and directions in which the heat medium flows are represented by dashed arrows.

[0043]

The discharged high-temperature, high-pressure refrigerant flows out of the outdoor unit 1 through the first refrigerant flow switching device 11 and check valve 13c and flows into the relay unit 2 through the portion of the refrigerant pipes 4 that is outside the outdoor unit 1. The first refrigerant flow switching device 11 is switched in such a manner that the high-temperature, high-pressure gaseous refrigerant discharged from the compressor 10 flows out of the outdoor unit 1 without passing through the heat source side heat exchanger 12 in the outdoor unit 1.

[0044]

After flowing into the relay unit 2 and passing through the second refrigerant flow switching device 28b, the high-temperature, high-pressure gaseous refrigerant flows into the heat medium heat exchanger 25b and exchanges heat with the heat medium. In so doing, the heat source side refrigerant becomes high-temperature, high-pressure liquid refrigerant and heats the heat medium. After becoming the high-temperature, high-pressure liquid refrigerant, the heat source side refrigerant is depressurized by passing through the expansion device 26b to become low-temperature, low-pressure two-phase gas-liquid refrigerant. In so doing, the expansion device 26b is controlled in such a manner that a degree of subcooling of the refrigerant at an outlet of the heat medium heat exchanger 25b will reach a target value. After becoming the low-temperature, low-pressure two-phase refrigerant, the heat source side refrigerant passes through the expansion device 26a, flows into the heat medium heat exchanger 25a, exchanges heat with the heat medium, and thereby cools the heat medium. In so doing, the expansion device 26a is fully open. On the other hand, the open-close device 29 and open-close device 27 are closed. Then, the refrigerant passes through the second refrigerant flow switching device 28a and flows out of the relay unit 2.

[0045]

After flowing out of the relay unit 2, the heat source side refrigerant passes through the portion of the refrigerant pipes 4 that is outside and flows into the outdoor unit 1. After flowing into the outdoor unit 1, the low-temperature, low-pressure, heat source side refrigerant passes through the check valve 13b and then through the heat source side heat exchanger 12. In so doing, the heat source side refrigerant exchanges heat with air in the outdoor space 6 and becomes low-temperature, low-pressure, gaseous heat source side refrigerant. The heat source side refrigerant is suctioned into the compressor 10 by passing through the first refrigerant flow switching device 11 and accumulator 19.

[0046]

Next, flows of heat medium in heating main operation mode will be described. As described above, the heat medium is cooled in the heat medium heat exchanger 25a and heated in the heat medium heat exchanger 25b. After being cooled in the heat medium heat exchanger 25a, the heat medium is transported by the pump 31a. Also, after being heated in the heat medium heat exchanger 25b, the heat medium is transported by the pump 31 b. The transported heat medium passes through the second heat medium flow switching devices 33 connected to the respective indoor units 3. In so doing, flow rates of the heat medium flowing into the indoor units 3 are adjusted in the respective heat medium flow control devices 34. Here, when the corresponding indoor units 3 are in heating mode, the second heat medium flow switching devices 33 are switched in such a manner that a flow path connected with the heat medium heat exchanger 25b and pump 31 b is communicated. On the other hand, when the corresponding indoor units 3 are in cooling mode, the second heat medium flow switching devices 33 are switched in such a manner that a flow path connected with the heat medium heat exchanger 25a and pump 31a is communicated. Then, the heat medium flows out of the relay unit 2 and then flows into the indoor units 3 through portions of the heat medium pipes 5 that are outside the relay unit 2.

[0047]

After flowing into the indoor units 3, the heat medium exchanges heat with air in the indoor space 7 at the use side heat exchangers 35. The heat-exchanged air in the indoor space 7 heats or cools rooms. The heat-exchanged heat medium flows out of the indoor units 3. After flowing out of the indoor units 3, the heat medium flows into the relay unit 2 through portions of the heat medium pipes 5 that are outside the relay unit 2.

[0048]

After flowing into the relay unit 2, the heat medium passes through the first heat medium flow switching devices 32. Here, when the corresponding indoor units 3 are in heating mode, the first heat medium flow switching devices 32 are switched in such a manner that the flow path connected with the heat medium heat exchanger 25b and pump 31 b is communicated. On the other hand, when the corresponding indoor units 3 are in cooling mode, the first heat medium flow switching devices 32 are switched in such a manner that the flow path connected with the heat medium heat exchanger 25a and pump 31 a is communicated. After passing through the flow paths, the heat medium is heated or cooled by exchanging heat in the heat medium heat exchangers 25.

[0049]

Fig. 5 is a diagram showing flows of refrigerant in cooling only operation mode of the air-conditioning device according to Embodiment 1 of the present invention.

An example in which all the indoor units 3 are in cooling mode will be described in Fig. 5. Here, in Fig. 5, the thick lines in the refrigerant cycle circuit represent portions of the refrigerant pipes 4 through which the heat source side refrigerant passes in heating only operation mode. Also, directions in which the heat source side refrigerant flows are represented by solid arrows and directions in which the heat medium flows are represented by dashed arrows.

[0050]

The discharged high-temperature, high-pressure refrigerant passes through the first refrigerant flow switching device 11 and then through the heat source side heat exchanger 12. By passing through the heat source side heat exchanger 12, the heat source side refrigerant exchanges heat with air in the outdoor space 6. The heat source side refrigerant becomes liquid refrigerant. After passing through the heat source side heat exchanger 12, the heat source side refrigerant flows out of the outdoor unit 1 through the check valve 13a. After flowing out of the outdoor unit 1, the heat source side refrigerant flows into the relay unit 2 through the portion of the refrigerant pipes 4 that is outside the outdoor unit 1. Here, the first refrigerant flow switching device 11 is switched in such a manner that the high-temperature, high-pressure gaseous heat source side refrigerant discharged from the compressor 10 passes through the heat source side heat exchanger 12.

[0051]

After flowing into the relay unit 2, the heat source side refrigerant passes through the open-close device 27, then branches, and passes through the expansion devices 26a and 26b. After passing through the expansion devices 26a and 26b, the heat source side refrigerant is depressurized to become low-temperature, low-pressure two-phase gas-liquid refrigerant and passes through the heat medium heat exchangers 25a and 25b. By passing through the heat medium heat exchangers 25a and 25b, the heat source side refrigerant exchanges heat with the heat medium. In so doing, the expansion devices 26a and 26b are controlled in such a manner that degrees of superheat of the heat source side refrigerant at heat medium outlets of the heat medium heat exchangers 25a and 25b will reach target values. The open-close device 29 is closed. After passing through the heat medium heat exchangers 25a and 25b, the heat source side refrigerant passes through the second refrigerant flow switching devices 28a and 28b, then joins together, and flows out of the relay unit 2. Here, the second refrigerant flow switching devices 28a and 28b are switched for cooling.

[0052]

After flowing out of the relay unit 2, the heat source side refrigerant passes through the portion of the refrigerant pipes 4 that is outside and flows into the outdoor unit 1. After flowing into the outdoor unit 1, the low-temperature, low-pressure, heat source side refrigerant, after flowing into the outdoor unit 1, the low-temperature, low-pressure, heat source side refrigerant, is suctioned into the compressor 10 by passing through the check valve 13c, first refrigerant flow switching device 11, and accumulator 19.

[0053]

Next, flows of heat medium in cooling only operation mode will be described.

As described above, the heat medium exchanges heat with low-temperature, low-pressure, heat source side refrigerant in the heat medium heat exchangers 25a and 25b and becomes a low-temperature heat medium. The heat medium turned into the low-temperature heat medium in the heat medium heat exchangers 25a and 25b is transported to the indoor units 3 by the pumps 31 a and 31 b connected to the heat medium heat exchangers 25a and 25b, respectively. The transported heat medium passes through the second heat medium flow switching devices 33 of the heat medium circuit side flow switching unit 23 connected to the respective indoor units 3. Then, flow rates of the heat medium flowing into the indoor units 3 are adjusted by the respective heat medium flow control devices 34. In so doing, the second heat medium flow switching devices 33 adjust the opening degrees to intermediate opening degrees or opening degrees suitable for temperatures of the heat medium at heat medium flow outlets of the heat medium heat exchangers 25a and 25b in such a manner that the heat medium transported from both the heat medium heat exchangers 25a and 25b can be supplied to the heat medium flow control devices 34 and indoor units 3. The heat medium flowing into the indoor units 3 connected by the heat medium pipes 5 exchanges heat with indoor air in the indoor space 7 at the use side heat exchangers 35 to cool the indoor space 7. After exchanging heat at the use side heat exchangers 35, the heat medium is transported into the relay unit 2 through the heat medium pipes 5 and heat medium flow control devices 34. The transported heat medium flows into the heat medium heat exchangers 25a and 25b through the first heat medium flow switching devices 32 of the heat medium circuit side flow switching unit 23 and receives heat from the refrigerant by amounts corresponding to the heat supplied to the indoor space 7 at the indoor units 3. Then, the heat medium is transported to the pumps 31a and 31b again.

[0054]

Fig. 6 is a diagram showing flows of refrigerant in cooling main operation mode of the air-conditioning device according to Embodiment 1 of the present invention. Here, in Fig. 6, the thick lines in the refrigerant cycle circuit represent portions of the refrigerant pipes 4 through which the heat source side refrigerant passes in heating only operation mode. Also, directions in which the heat source side refrigerant flows are represented by solid arrows and directions in which the heat medium flows are represented by dashed arrows.

[0055]

[0056]

After flowing into the relay unit 2, the heat source side refrigerant passes through the second refrigerant flow switching device 28b, and flows into the heat medium heat exchanger 25b. In so doing, the second refrigerant flow switching device 28a is switched to a flow path for cooling. On the other hand, the second refrigerant flow switching device 28b is switched to a flow path for heating. After flowing into the heat medium heat exchanger 25b, the heat source side refrigerant exchanges heat with the heat medium. The heat source side refrigerant becomes high-temperature, high-pressure liquid refrigerant and heats the heat medium. After becoming the high-temperature, high-pressure liquid refrigerant, the heat source side refrigerant is depressurized by passing through the expansion device 26b to become low-temperature, low-pressure two-phase gas-liquid refrigerant. In so doing, the expansion device 26b is controlled in such a manner that a degree of superheat of the heat medium at a heat medium flow outlet of the heat medium heat exchanger 25a will reach a target value. After becoming the low-temperature, low-pressure two-phase refrigerant, the refrigerant passes through the heat medium heat exchanger 25a, exchanges heat with the heat medium in a refrigerant-water heat exchanger, and then flows out of the relay unit 2. Here, the open-close device 29 is closed.

[0057]

[0058]

Next, flows of heat medium in cooling main operation mode will be described. As described above, the heat medium is cooled in the heat medium heat exchanger 25a and heated in the heat medium heat exchanger 25b. After being cooled in the heat medium heat exchanger 25a, the heat medium is transported by the pump 31a. Also, after being heated in the heat medium heat exchanger 25b, the heat medium is transported by the pump 31 b. The transported heat medium passes through the second heat medium flow switching devices 33 connected to the respective indoor units 3. In so doing, flow rates of the heat medium flowing into the indoor units 3 are adjusted in the respective heat medium flow control devices 34. Here, when the corresponding indoor units 3 are in heating mode, the second heat medium flow switching devices 33 are switched in such a manner that the flow path connected with the heat medium heat exchanger 25b and pump 31 b is communicated. On the other hand, when the corresponding indoor units 3 are in cooling mode, the second heat medium flow switching devices 33 are switched in such a manner that the flow path connected with the heat medium heat exchanger 25a and pump 31a is communicated. Then, the heat medium flows out of the relay unit 2 and then flows into the indoor units 3 through the portions of the heat medium pipes 5 that are outside the relay unit 2.

[0059]

After flowing into the indoor units 3, the heat medium exchanges heat with air in the indoor space 7 at the use side heat exchangers 35. The heat-exchanged air in the indoor space 7 heats or cools rooms. The heat-exchanged heat medium flows out of the indoor units 3. After flowing out of the indoor units 3, the heat medium flows into the relay unit 2 through the portions of the heat medium pipes 5 that are outside the relay unit 2.

[0060]

[0061]

Fig. 7 is a diagram illustrating another form of the air-conditioning device according to Embodiment 1 of the present invention. To obtain an air-conditioning device that does not need to perform cooling and heating mixed operation while maintaining a configuration containing the refrigerant cycle circuit and heat medium cycle circuit, the air-conditioning device as shown in Fig. 7 can be used. Here, in Fig. 7, description will be given of a case in which a heat exchange unit 22 containing one heat medium heat exchanger 25 and one expansion device 26 is provided in the relay unit 2.

[0062]

The relay unit 2 of the air-conditioning device of Fig. 7 has a configuration that does not include the refrigerant circuit side flow switching unit 21, which is installed in the air-conditioning device of Fig. 2. Consequently, in the refrigerant cycle circuit, portions of the refrigerant pipes 4 that are outside the relay unit 2 are connected directly to the heat medium heat exchanger 25 and expansion device 26 of the heat exchange unit 22. In the heat medium cycle circuit, the heat medium circuit side flow switching unit 23, which is installed in the air-conditioning device of Fig. 2, is not provided. Consequently, in the refrigerant cycle circuit, portions of the refrigerant pipes 4 that are outside the heat medium adjustment unit 24 and relay unit 2 are connected directly to the heat medium heat exchanger 25 and pump 31 of the heat exchange unit 22. Installation of the first connecting pipe 4a, second connecting pipe 4b, and checkvalves 13a to 13d in the outdoor unit 1 is omitted.

[0063]

As the relay unit 2 includes units that are necessary for operating specifications, application, and other features of air-conditioning devices, components can be shared among the air-conditioning devices differing in the specifications, application, and other features. Also, as heat medium transport power can be reduced, energy can be saved. Furthermore, the use of a heat medium such as water is consideration given to safety of users.

[0064]

Fig. 8 is a diagram showing flows of refrigerant in heating operation mode of the other form of the air-conditioning device according to Embodiment 1 of the present invention. Here, in Fig. 8, directions in which the heat source side refrigerant flows are represented by solid arrows and directions in which the heat medium flows are represented by dashed arrows.

[0065]

The discharged high-temperature, high-pressure refrigerant flows out of the outdoor unit 1 through the first refrigerant flow switching device 11 and flows into the relay unit 2 through the portion of the refrigerant pipes 4 that is outside the outdoor unit 1.

Here, the first refrigerant flow switching device 11 is switched in such a manner that the high-temperature, high-pressure gaseous refrigerant discharged from the compressor 10 flows out of the outdoor unit 1 without passing through the heat source side heat exchanger 12 in the outdoor unit 1.

[0066]

The gaseous heat source side refrigerant flowing into the relay unit 2 passes through the heat medium heat exchanger 25a. In so doing, the heat source side refrigerant exchanges heat with the heat medium. After passing through the heat medium heat exchanger 25a, the heat source side refrigerant becomes high-temperature, high-pressure liquid refrigerant. After becoming the high-temperature, high-pressure liquid refrigerant, the heat source side refrigerant is depressurized by passing through the expansion device 26a and thereby becomes low-temperature, low-pressure two-phase gas-liquid refrigerant. After passing through the expansion device 26a, the low-temperature, low-pressure, two-phase gas-liquid, heat source side refrigerant flows out of the relay unit 2.

[0067]

After flowing out of the relay unit 2, the heat source side refrigerant passes through the portion of the refrigerant pipes 4 that is outside and flows into the outdoor unit 1. After flowing into the outdoor unit 1, the low-temperature, low-pressure, heat source side refrigerant passes through the heat source side heat exchanger 12. In so doing, the heat source side refrigerant exchanges heat with air in the outdoor space 6 and becomes low-temperature, low-pressure, gaseous heat source side refrigerant. The heat source side refrigerant is suctioned into the compressor 10 by passing through the first refrigerant flow switching device 11 and accumulator 19. [0068]

Next, flows of heat medium in heating operation mode will be described. As described above, the heat medium exchanges heat with high-temperature, high-pressure gaseous refrigerant in the heat medium heat exchangers 25a and 25b and becomes a high-temperature heat medium. The heat medium turned into the high-temperature heat medium in the heat medium heat exchangers 25a and 25b is transported to the indoor units 3 by the pumps 31a and 31b connected to the heat medium heat exchangers 25a and 25b, respectively. In so doing, flow rates of the heat medium flowing into the indoor units 3 are adjusted by the respective heat medium flow control devices 34. The heat medium flowing into the indoor units 3 connected by the heat medium pipes 5 exchanges heat with indoor air in the indoor space 7 at the use side heat exchangers 35 to heat the indoor space 7. After exchanging heat at the use side heat exchangers 35, the heat medium is transported into the relay unit 2 through the heat medium pipes 5 and heat medium flow control devices 34. The refrigerant sent to the relay unit 2, the transported heat medium is heated by passing through the heat medium heat exchangers 25a and 25b and is transported by the pumps 31 a and 31 b again.

[0069]

Fig. 9 is a diagram showing flows of refrigerant in cooling operation mode of the other form of the air-conditioning device according to Embodiment 1 of the present invention. Here, in Fig. 9, directions in which the heat source side refrigerant flows are represented by solid arrows and directions in which the heat medium flows are represented by dashed arrows.

[0070]

The discharged high-temperature, high-pressure refrigerant passes through the first refrigerant flow switching device 11 and then through the heat source side heat exchanger 12. By passing through the heat source side heat exchanger 12, the heat source side refrigerant exchanges heat with air in the outdoor space 6. The heat source side refrigerant becomes liquid refrigerant. After passing through the heat source side heat exchanger 12, the heat source side refrigerant flows out of the outdoor unit 1. After flowing out of the outdoor unit 1, the heat source side refrigerant flows into the relay unit 2 through the portion of the refrigerant pipes 4 that is outside the outdoor unit 1. Here, the first refrigerant flow switching device 11 is switched in such a manner that the high-temperature, high-pressure gaseous heat source side refrigerant discharged from the compressor 10 passes through the heat source side heat exchanger 12.

[0071]

The heat source side refrigerant flowing into the relay unit 2 passes through the expansion device 26a. After passing through the expansion device 26a, the heat source side refrigerant is depressurized to become low-temperature, low-pressure two-phase gas-liquid refrigerant and passes through the heat medium heat exchanger 25a. The heat source side refrigerant passing through the heat medium heat exchanger 25a exchanges heat with the heat medium. In so doing, the expansion device 26a is controlled in such a manner that a degree of superheat of the heat source side refrigerant at the heat medium outlet of the heat medium heat exchanger 25a will reach a target value. After passing through the heat medium heat exchanger 25a, the heat source side refrigerant flows out of the relay unit 2.

[0072]

After flowing out of the relay unit 2, the heat source side refrigerant passes through the portion of the refrigerant pipes 4 that is outside and flows into the outdoor unit 1. After flowing into the outdoor unit 1, the low-temperature, low-pressure, heat source side refrigerant, after flowing into the outdoor unit 1, the low-temperature, low-pressure, heat source side refrigerant, is suctioned into the compressor 10 by passing through the first refrigerant flow switching device 11 and accumulator 19.

[0073]

Next, flows of heat medium in cooling operation mode will be described. As described above, the heat medium exchanges heat with low-temperature, low-pressure gaseous refrigerant in the heat medium heat exchangers 25a and 25b and becomes a low-temperature heat medium. The heat medium turned into the low-temperature heat medium in the heat medium heat exchangers 25a and 25b is transported to the indoor units 3 by the pumps 31a and 31b connected to the heat medium heat exchangers 25a and 25b, respectively. In so doing, flow rates of the heat medium flowing into the indoor units 3 are adjusted by the respective heat medium flow control devices 34. The heat medium flowing into the indoor units 3 connected by the heat medium pipes 5 exchanges heat with indoor air in the indoor space 7 at the use side heat exchangers 35 to cool the indoor space 7. After exchanging heat at the use side heat exchangers 35, the heat medium is transported into the relay unit 2 through the heat medium pipes 5 and heat medium flow control devices 34. The refrigerant sent to the relay unit 2, the transported heat medium is cooled by passing through the heat medium heat exchangers 25a and 25b and is transported by the pumps 31 a and 31 b again.

[0074]

As described above, with the air-conditioning device of Embodiment 1, in which the relay unit 2 includes the modularized refrigerant circuit side flow switching unit 21, heat exchange unit 22, heat medium circuit side flow switching unit 23, and heat medium adjustment unit 24 and the units are configured to be mounted and demounted depending on the operating form and other conditions of the air-conditioning device, circuit configuration can be changed depending on application. Because there is no need to install units unnecessary for the configuration, installation area, and cost can be reduced.

[0075]

Fig. 10 is a diagram showing a configuration of another air-conditioning device according to Embodiment 1 of the present invention. Furthermore, with the heat medium circuit side flow switching units 23 and heat medium adjustment units 24 being provided separately from the relay unit 2, in cooling and heating mixed operation, the number of the indoor units 3 can be increased by connecting plural heat medium circuit side flow switching units 23a and heat medium circuit side flow switching units 23b in parallel and connecting heat medium adjustment units 24a and heat medium adjustment units 24b in parallel.

[0076]

Furthermore, as the heat medium rather than the heat source side refrigerant circulates in the indoor units 3 used to heat or cool the air in the indoor space 7, leakage of the heat source side refrigerant into indoor space 7 can be inhibited, which results in increased safety. Also, because pipes for circulation of the heat medium can be reduced compared to those of an air-conditioning device such as a chiller, transport power can be reduced.

[0077]

Embodiment 2

Fig. 11 is a diagram showing a configuration of an air-conditioning device according to Embodiment 2 of the present invention. In the air-conditioning device of Embodiment 1 described above that does not need to perform cooling and heating mixed operation, a heat exchange unit 22 containing one heat medium heat exchanger 25 and one expansion device 26 is provided in the relay unit 2. In the air-conditioning device of Embodiment 2, a heat exchange unit 22 containing two heat medium heat exchangers 25 and two expansion devices 26 are provided in the relay unit 2.

[0078]

The provision of two heat medium heat exchangers 25 and two expansion devices 26 in the relay unit 2 makes it possible to increase heat exchange capacity of the heat medium heat exchangers 25. Consequently, a greater amount of heat can be supplied from the refrigerant cycle circuit to the heat medium cycle circuit. This configuration makes it possible to increase the number of the indoor units 3 in the heat medium cycle circuit.

[0079]

Fig. 12 is a diagram showing a configuration of another air-conditioning device according to Embodiment 2 of the present invention. As shown in Fig. 12, when the refrigerant circuit side flow switching unit 21 is provided, the first connecting pipe 4a, second connecting pipe 4b, and check valves 13a to 13d may be kept mounted in the outdoor unit 1. This configuration makes it possible to obtain the air-conditioning device without changing the configuration of the outdoor unit 1.

Reference Signs List [0080] 1 outdoor unit 2 relay unit 3, 3a, 3b, 3c, 3d indoor unit 4 refrigerant pipe 4a first connecting pipe 4b second connecting pipe 5 heat medium pipe 6 outdoor space 7 indoor space 10 compressor 11 first refrigerant flow switching device 12 heat source side heat exchanger 13a, 13b, 13c, 13d checkvalve 19 accumulator 21 refrigerant circuit side flow switching unit 22 heat exchange unit 23, 23a, 23b heat medium circuit side flow switching unit 24, 24a, 24b heat medium adjustment unit 25, 25a, 25b heat medium heat exchanger 26, 26a, 26b expansion device 27, 29 open-close device 28, 28a, 28b second refrigerant flow switching device 31,31a, 31b pump 32, 32a, 32b, 32c, 32d first heat medium flow switching device33, 33a, 33b, 33c, 33d second heat medium flow switching device 34, 34a, 34b, 34c, 34d heat medium flow control device 35, 35a, 35b, 35c, 35d use side heat exchanger 40, 40a, 40b temperature sensor

Claims

CLAIMS [Claim 1] An air-conditioning device, comprising: a heat source side refrigerant cycle circuit configured to circulate heat source side refrigerant, the heat source side refrigerant cycle circuit including a compressor configured to compress the heat source side refrigerant, a first refrigerant flow switching device configured to switch circulation paths of the heat source side refrigerant, a heat source side heat exchanger configured to make the heat source side refrigerant exchange heat, an expansion device configured to adjust pressure of the heat source side refrigerant, and an intermediate heat exchanger configured to exchange heat between the heat source side refrigerant and a heat medium different from the heat source side refrigerant, the compressor, the first refrigerant flow switching device, the heat source side heat exchanger, the expansion device, and the intermediate heat exchanger being connected by pipes; and a heat medium cycle circuit configured to circulate the heat medium, the heat medium cycle circuit including the intermediate heat exchanger, a pump configured to pressurize the heat medium, and a use side heat exchanger configured to exchange heat between the heat medium and air in an air-conditioned space, the intermediate heat exchanger, the pump, and the use side heat exchanger being connected by pipes, the compressor, the first refrigerant flow switching device, and the heat source side heat exchanger being housed in an outdoor unit, the intermediate heat exchanger and the expansion device being housed in a heat exchange unit, the use side heat exchanger being housed in an indoor unit, the air-conditioning device further comprising: a refrigerant circuit side flow switching unit connected between the outdoor unit and the heat exchange unit by pipes, installed in such a manner that the refrigerant circuit side flow switching unit is allowed to be removed, and provided with a second refrigerant flow switching device configured to switch circulation paths of the heat source side refrigerant in the heat source side refrigerant cycle circuit; and a heat medium circuit side flow switching unit connected between the heat exchange unit and the indoor unit by pipes, installed in such a manner that the heat medium circuit side flow switching unit is allowed to be removed, and provided with a heat medium flow switching device configured to switch circulation paths of the heat medium in the heat medium cycle circuit. [Claim 2] The air-conditioning device of claim 1, wherein a plurality of the heat medium circuit side flow switching units are connected with the heat exchange unit by pipes in parallel to one another.