AIR-CONDITIONING APPARATUS

TECHNICAL FIELD

The present disclosure relates to an air-conditioning apparatus that causes heat exchange to be performed between refrigerant that circulates in a refrigerant circuit and a heat medium that circulates in a heat medium circuit.

BACKGROUND ART

In the past, an air-conditioning composite system has been proposed that can simultaneously condition air and supply hot water (see Patent Literature 1, for example). In the air conditioning composite system that simultaneously condition air and supply hot water, generally, an air-conditioning apparatus and a water heater are connected in parallel, and an air-conditioning temperature and a hot water supply temperature can be set individually.

CITATION LIST
Patent Literature

Patent Literature 1: Japanese Unexamined Patent Application Publication No. 4-263758

SUMMARY OF INVENTION
Technical Problem

However, as described in Patent Literature 1, in the case where the air-conditioning apparatus and the water heater are connected in parallel, a large amount of heat remains in return water that flows out from the air-conditioning apparatus and the water heater. In an existing air-conditioning composite system, for example, heat recovered by an air-conditioning apparatus cannot be used in a water heater, that is, heat remaining in return water cannot be effectively used. Therefore, the energy efficiency for energy savings in the entire system is reduced.

The present disclosure is applied to solve the above problem of the existing air-conditioning composite system, and relates to an air-conditioning apparatus that can improve an energy efficiency of the entire system for energy savings.

Solution to Problem

An air-conditioning apparatus according to an embodiment of the present disclosure includes a cooling device, a heating device, and a heat-medium circulation circuit in which a heat medium circulates. The cooling device includes a cooling refrigerant circuit in which cooling refrigerant circulates, and a cooling-side intermediate heat exchanger that causes heat exchange to be performed between the cooling refrigerant that flows in the cooling refrigerant circuit and the heat medium, and also operates as a condenser in the cooling refrigerant circuit. The heating device includes a heating refrigerant circuit in which heating refrigerant circulates, and a heating-side intermediate heat exchanger that causes heat exchange to be performed between the heat medium and the heating refrigerant that flows in the heating refrigerant circuit, and also operates as an evaporator in the heating refrigerant circuit. The cooling device and the heating device are connected in series in the heat-medium circulation circuit.

Advantageous Effects of Invention

According to embodiments of the present disclosure, a cooling device and a heating device are connected in series, a heat medium is caused to flow in the cooling device and the heating device, and the cooling device and the heating device use exhaust heat recovered by the cooling device and the heating device. It is therefore possible to improve an energy efficiency for energy saving.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic view illustrating an example of the configuration of an air-conditioning apparatus according to Embodiment 1.

FIG. 2 is a schematic view illustrating an example of the configuration of an indoor unit as illustrated in FIG. 1.

FIG. 3 is a functional block diagram illustrating an example of the configuration of a controller as illustrated in FIG. 1.

FIG. 4 is a top cross-sectional view illustrating an example of the configuration of a heat-medium flow adjusting valve as illustrated in FIG. 1.

FIG. 5 is a top cross-sectional view schematically illustrating a first state of the heat-medium flow adjusting valve as illustrated in FIG. 4.

FIG. 6 is a top cross-sectional view schematically illustrating a second state of the heat-medium flow adjusting valve as illustrated in FIG. 4.

FIG. 7 is a top cross-sectional view schematically illustrating a third state of the heat-medium flow adjusting valve as illustrated in FIG. 4.

FIG. 8 is a top cross-sectional view schematically illustrating a fourth state of the heat-medium flow adjusting valve as illustrated in FIG. 4

FIG. 9 is a top cross-sectional view schematically illustrating a fifth state of the heat-medium flow adjusting valve as illustrated in FIG. 4.

FIG. 10 is a top cross-sectional view schematically illustrating a sixth state of the heat-medium flow adjusting valve as illustrated in FIG. 4.

FIG. 11 is a schematic view for explaining the flow of a heat medium.

FIG. 12 is a schematic view indicating opening degrees of heat-medium flow adjusting valves that are associated with the FCUs of a system #1 as illustrated in FIG. 11.

FIG. 13 is a schematic view indicating the opening degrees of the heat-medium flow adjusting valves 22 in the case where a FCU is made to be in a thermo-off state.

FIG. 14 is a schematic view indicating the opening degrees of the heat-medium flow adjusting valves in the case where the FCU performance of a FCU, which is a representative FCU, varies.

FIG. 15 is a schematic view illustrating an example of the configuration of an air-conditioning apparatus according to Embodiment 2.

FIG. 16 is a schematic view illustrating an example of the configuration of an air-conditioning apparatus according to Embodiment 3.

FIG. 17 is a schematic view indicating a first example of the opening degrees of the heat-medium flow adjusting valves in the case where representative FCUs in systems #1 to #3 have different FCU performance.

FIG. 21 is a schematic view illustrating an example of the configuration of an air-conditioning apparatus according to Embodiment 4.

FIG. 22 is a schematic view illustrating an example of the configuration of an air-conditioning apparatus according to Embodiment 5.

FIG. 23 is a flowchart illustrating an example of the flow of processing in the case where heat recovery by a cooling-side intermediate heat exchanger and that by a heating-side intermediate heat exchanger in Embodiment 5 are not balanced.

DESCRIPTION OF EMBODIMENTS
Embodiment 1

An air-conditioning apparatus according to Embodiment 1 of the present disclosure will be described. FIG. 1 is a schematic view illustrating an example of the configuration of an air-conditioning apparatus 100 according to Embodiment 1. As illustrated in FIG. 1, the air-conditioning apparatus 100 includes an outdoor unit 1, indoor units 2a to 2c, and a relay unit 3. The outdoor unit 1 and the relay unit 3 are connected by a refrigerant pipe 10, whereby a refrigerant circuit is formed. The indoor units 2a to 2c and the relay unit 3 are connected by a heat medium pipe 20, whereby a heat medium circuit is formed. The indoor units 2a to 2c are connected in series.

[Configuration of Air-Conditioning Apparatus 100]
(Outdoor Unit 1)

The outdoor unit 1 includes a compressor 11, a refrigerant-flow switching device 12, a heat-source-side heat exchanger 13, and an accumulator 14. The compressor 11 sucks low-temperature, low pressure refrigerant, compresses the sucked refrigerant into high-temperature, high-pressure refrigerant, and discharges the high-temperature, high-pressure refrigerant. For example, the compressor 11 is, for example, an inverter compressor the capacity of which is controlled by changing its operating frequency. It should be noted that this capacity is the amount of refrigerant that is discharged per unit time. The operating frequency of the compressor 11 is controlled by a controller 4 provided in the relay unit 3, which will be described later.

The refrigerant-flow switching device 12 is, for example, a four-way valve, and switches the flow direction of refrigerant to switch the operation to be performed between a cooling operation and a heating operation. During the cooling operation, a flow passage in the refrigerant-flow switching device 12 is switched such that the discharge side of the compressor 11 and the heat-source-side heat exchanger 13 are connected to each other as indicated by a solid line in FIG. 1. During the heating operation, the flow passage in the refrigerant-flow switching device 12 is switched such that the discharge side of the compressor 11 and the relay unit 3 are connected to each other as indicated by a broken line in FIG. 1. Switching of the flow passage in the refrigerant-flow switching device 12 is controlled by the controller 4.

The heat-source-side heat exchanger 13 causes heat exchange to be performed between refrigerant and outdoor air that is supplied by, for example, a fan (not illustrated). During the cooling operation, the heat-source-side heat exchanger 13 operates as a condenser that transfers heat of the refrigerant to outdoor air to condense the refrigerant. During the heating operation, the heat-source-side heat exchanger 13 operates as an evaporator that evaporates the refrigerant to cool the outdoor air by heat of vaporization produced when the refrigerant is evaporated.

The accumulator 14 is provided on a low-pressure side of the compressor 11 that is a suction side of the compressor 11. The accumulator 14 separates surplus refrigerant the amount of which corresponds to the difference between the amount of the refrigerant that flows during the cooling operation and the amount of the refrigerant that flows during the heating operation, or surplus refrigerant the amount of which corresponds to the difference between the amount of the refrigerant that flows after a transient change of the operation and the amount of the refrigerant that flows before the transient change of the operation, into gas refrigerant and liquid refrigerant, and then stores the liquid refrigerant.

(Indoor Units 2a to 2c)

FIG. 2 is a schematic view illustrating an example of the configuration of the indoor unit 2a to 2c as illustrated in FIG. 1. As illustrated in FIG. 2, each of the indoor units 2a to 2c includes a fan coil unit (hereinafter referred to as “FCU”) 21 and a heat-medium flow adjusting valve 22.

The FCU 21 includes a use-side heat exchanger 121 and a fan 122. The use-side heat exchanger 121 causes heat exchange to be performed between water and indoor air that is supplied by the fan 122. As a result, cooling air or heating air is generated as conditioned air to be supplied into an indoor space. The fan 122 supplies air to the use-side heat exchanger 121. The rotation speed of the fan 122 is controlled by the controller 4. The amount of air that is supplied to the use-side heat exchanger 121 is controlled by controlling the rotation speed.

The heat-medium flow adjusting valve 22 is, for example, an electric three-way valve having an inflow port 22a, a first outflow port 22b, and a second outflow port 22c, and is provided on a water inflow side of the FCU 21. The heat-medium flow adjusting valve 22 is provided to divide water that has flowed into the heat-medium flow adjusting valve 22. The first outflow port 22b of the heat-medium flow adjusting valve 22 is connected to the water inflow side of the FCU 21. The second outflow port 22c is connected to the water outflow side of the FCU 21 by an indoor-side bypass pipe 23. Therefore, the second outflow port 22c of the heat-medium flow adjusting valve 22 and the water outflow side of the FCU 21 are connected.

In this example, in the indoor unit 2a to 2c, respective indoor-side bypass pipes 23 are provided. This, however, is not limiting. The indoor-side bypass pipes 23 may be provided outside the indoor unit 2a to 2c, and connected to the indoor unit 2a to 2c by, for example, connection fittings. In such a configuration, the length of the indoor-side bypass pipe 23 is smaller than that in the case where the indoor-side bypass pipe 23 is provided in the indoor unit. It is therefore possible to reduce a loss caused by heat radiation that occurs when water flows through the pipe. Furthermore, it is not necessarily indispensable that the indoor-side bypass pipes 23 are provided in all the indoor units 2a to 2c. For example, of the FCUs 21, a FCU 21 or FCUs 21 may be provided with an indoor-side bypass pipe or pipes 23 in the case where the FCU 21 or FCUs 21 do not need to cause water to flow therethrough.

In the case where the heat-medium flow adjusting valve 22 includes at least the inflow port 22a, the first outflow port 22b, and the second outflow port 22c, the heat-medium flow adjusting valve 22 may be a multi-way valve such as a four-way valve. To be more specific, for example, as the heat-medium flow adjusting valve 22, a four-way valve may be used, and the four-way valve may be used as a pseudo three-way valve by using an outflow port other than the first outflow port 22b and the second outflow port 22c, for other applications, or by closing the outflow port other than the first outflow port 22b and the second outflow port 22c in order to inhibit use of the outflow port. It should be noted that as in Embodiment 1, it is optimal that the heat-medium flow adjusting valve 22 is a three-way valve having a flow rate control function and a block function that can be fulfilled by adjusting the opening degree of the valve, that is, can divide water that flows into the heat-medium flow adjusting valve 22, while adjusting the flow rate of the water, and that can block each of the divided water. Instead of using the heat-medium flow adjusting valve 22, it may be possible to use, for example, a combination of a three-way valve that controls the flow rate and an expansion device that blocks flowing water. Alternatively, for example, at a location between a branch point and a junction of a pipe provided on the inflow side of the FCU 21 and at the indoor-side bypass pipe 23, respective expansion units may be provided.

Furthermore, each of the indoor units 2a to 2c includes an inlet temperature sensor 24, an outlet temperature sensor 25, and a suction temperature sensor 26. The inlet temperature sensor 24 is provided on the water inflow side of the FCU 21 to detect the temperature of water that flows into the FCU 21. The outlet temperature sensor 25 is provided on a water outflow side of the FCU 21 to detect the temperature of water that flows out of the FCU 21. The suction temperature sensor 26 is provided on an air suction side of the FCU 21 to detect information on the temperature of air sucked into the FCU 21.

(Relay Unit 3)

The relay unit 3 as illustrated in FIG. 1 includes an expansion valve 31, an intermediate heat exchanger 32, a pump 33, and the controller 4. The expansion valve 31 causes refrigerant to expand. The expansion valve 31 is a valve whose opening degree can be controlled, for example, an electronic expansion valve. The opening degree of the expansion valve 31 is controlled by the controller 4.

The intermediate heat exchanger 32 operates as a condenser or an evaporator, and causes heat exchange to be performed between refrigerant that flows in the refrigerant circuit connected with a refrigerant-side flow passage and a heat medium that flows in the heat medium circuit connected with a heat-medium-side flow passage. During the cooling operation, the intermediate heat exchanger 32 operates as an evaporator that evaporates refrigerant to cool a heat medium by heat of vaporization produced when the refrigerant is evaporated. During the heating operation, the intermediate heat exchanger 32 operates as a condenser that condenses refrigerant by transferring heat of the refrigerant to the heat medium.

The pump 33 is driven by a motor (not illustrated), and circulates water that flows through the heat medium pipe 20 and that is a heat medium. For example, the pump 33 is a pump whose capacity can be controlled. The flow rate of the water that is circulated by the pump 33 can be controlled in accordance with the load on each of the indoor unit 2a to 2c. The driving of the pump 33 is controlled by the controller 4. More specifically, the pump 33 is controlled by the controller 4 such that the greater the above load, the higher the flow rate of water, and the smaller the load, the lower the flow rate of water.

(Controller 4)

The controller 4 controls the operation of the entire air-conditioning apparatus 100 that includes the outdoor unit 1, the indoor units 2a to 2c, and the relay unit 3, based on various information that is transmitted from respective units, for example, temperatures at locations upstream and downstream of respective use-side heat exchangers 121 in the air-conditioning apparatus 100, and pressures of a heat medium at locations upstream and downstream of the pump 33. More specifically, the controller 4 controls the operating frequency of the compressor 11, the driving of the pump 33, the opening degrees of the heat-medium flow adjusting valves 22, the opening degree of the expansion valve 31, etc. Particularly, in Embodiment 1, the controller 4 controls the driving of the pump 33 and the opening degrees of the heat-medium flow adjusting valves 22 based on the performance of the FCUs 21.

The controller 4 is hardware, such as a circuit device, that fulfills various functions, or that fulfills various functions by executing software on an arithmetic unit such as a microcomputer. In this example, the controller 4 is provided in the relay unit 3. This, however, is not limiting. The controller 4 may be provided in any one of the outdoor unit 1 and the indoor units 2a to 2c. Alternatively, the outdoor unit 1 and the indoor units 2a to 2c may be provided with respective controllers 4.

FIG. 3 is a functional block diagram illustrating an example of the configuration of the controller 4 as illustrated in FIG. 1. As illustrated in FIG. 3, the controller 4 includes an FCU performance calculation unit 41, a valve opening-degree determination unit 42, a valve control unit 43, a heat-medium flow-rate determination unit 44, a pump control unit 45, and a storage unit 46.

The FCU performance calculation unit 41 calculates FCU performance that each of the FCUs 21 is currently required to achieve. The FCU performance is the operating performance [kW] of the FCU 21 that is required to condition air such that the temperature of the air reaches a set temperature. The FCU performance is calculated based on various temperatures detected by the inlet temperature sensor 24, the outlet temperature sensor 25, and the suction temperature sensor 26, and set FCU performance, a set outlet/inlet temperature difference, and a set water/air temperature difference that are stored in the storage unit 46.

The set FCU performance is FCU performance set in advance for the FCU 21. The set outlet/inlet temperature difference is a set temperature difference between the outlet temperature of water that flows out of the FCU 21 and the inlet temperature of water that flows into the FCU 21. The set water/air temperature difference is a set temperature difference between the temperature of air that is sucked into the FCU 21 and the inlet temperature of water that flows into the FCU 21.

Based on the calculated FCU performance of each FCU 21, the valve opening-degree determination unit 42 determines the opening degree of an associated heat-medium flow adjusting valve 22. The valve control unit 43 produces a control signal for controlling the opening degree of the above associated heat-medium flow adjusting valve 22 based on the opening degree determined by the valve opening-degree determination unit 42, and the valve control unit 43 sends the control signal to the heat-medium flow adjusting valve 22.

The heat-medium flow-rate determination unit 44 determines the flow rate of water that flows into each FCU 21 based on the calculated FCU performance of each FCU 21. To be more specific, the heat-medium flow-rate determination unit 44 determines the flow rate of water such that the higher the FCU performance, the higher the flow rate of water that is made to flow into the FCU 21, and the lower the FCU performance, the lower the flow rate of water that is made to flow into the FCU 21. The pump control unit 45 produces a control signal for controlling the driving of the pump 33 based on the flow rate of water determined by the heat-medium flow-rate determination unit 44, and the pump control unit 45 sends the control signal to the pump 33.

The set FCU performance, the set outlet/inlet temperature difference, and the set water/air temperature differences which are all referred to by the FCU performance calculation unit 41, are stored in advance in the storage unit 46.

[Configuration of Heat-Medium Flow Adjusting Valve 22]

FIG. 4 is a top cross-sectional view illustrating an example of the configuration of the heat-medium flow adjusting valve 22 as illustrated in FIG. 1. As illustrated in FIG. 4, the heat-medium flow adjusting valve 22 includes a body 22d having a hollow columnar shape, and the inflow port 22a that is located at a center portion of an upper surface or a bottom surface of the body 22d. The inflow port 22a is a port through which a heat medium flows into the heat-medium flow adjusting valve 22. Furthermore, in a side surface of the body 22d of the heat-medium flow adjusting valve 22, the first outflow port 22b and the second outflow port 22c through which the heat medium flows out are provided.

The first outflow port 22b is connected with the FCU 21, and the second outflow port 22c is connected with the indoor-side bypass pipe 23. In the case where the side surface of the body 22d is divided into regions arranged at an intervals of an angle of 120 degrees, that is, regions each curved through an angle of 120 degrees about the center axis, which is the normal to the upper surface or the bottom surface of the body 22d, the side surface of the body 22d is divided into the following three regions: a first region curved from a position corresponding to 0 degree to a position corresponding to 120 degrees; a second region curved from the position corresponding to 120 degrees to a position corresponding to 240 degrees; and a third region curved from the position corresponding to 240 degrees to a position corresponding to 360 degrees. The first outflow port 22b is formed in the first region of the above three regions of the side surface. The second outflow port 22c is formed in the second region of the three regions of the side surface.

An opening-degree adjusting valve 22e having a cylindrical shape is provided in the internal space of the body 22d. The opening-degree adjusting valve 22e has an opening portion 22h, which is an opening formed in part of the opening-degree adjusting valve 22e that corresponds to part of an arc cross section thereof, and the opening portion 22h has a C-shaped cross section. The opening portion 22h extends in such a manner to curve about the center axis through 120 degrees.

In the heat-medium flow adjusting valve 22, a side wall 22f is provided on an inner periphery of a side surface located in the third region of the above divided regions, that is, the first to third regions, such that the side wall 22f has a greater thickness than side surfaces provided in the first and second regions. The side wall 22f is provided in such a manner as to contact an outer periphery of the opening-degree adjusting valve 22e. Furthermore, a partition wall 22g is provided on an inner periphery of a side surface located at a boundary portion between the first region and the second region such that the partition wall 22g contacts the opening-degree adjusting valve 22e. The partition wall 22g divides water that has flowed into the heat-medium flow adjusting valve 22 through the inflow port 22a such that the divided water flows out from the first outflow port 22b and also flows out from the second outflow port 22c.

The opening-degree adjusting valve 22e is rotated along the side wall 22f and the partition wall 22g about the center axis. Since the heat-medium flow adjusting valve 22 is formed in the above manner, flow passages that each allows water to flow therethrough in accordance with a rotation state of the opening-degree adjusting valve 22e are provided between the inflow port 22a and the first outflow port 22b and between the inflow port 22a and the second outflow port 22c.

FIGS. 5 to 10 are top cross-sectional views schematically illustrating respective states in which the opening-degree adjusting valve 22e of the heat-medium flow adjusting valve 22 as illustrated in FIG. 4 is rotated. It should be noted that the opening degree of the opening-degree adjusting valve 22e that is opened to allow the inflow port 22a and the first outflow port 22b to communicate with each other and thus allow water to flow from the inflow port 22a to the first outflow port 22b will be referred to as “FCU opening degree”. Furthermore, the opening degree of the opening-degree adjusting valve 22e that is opened to allow the inflow port 22a and the second outflow port 22c to communicate with each other and thus allow water to flow to the second outflow port 22c through the inflow port 22a will be referred to as “bypass opening degree”.

FIG. 5 is a top cross-sectional view schematically illustrating a first state of the heat-medium flow adjusting valve 22 as illustrated in FIG. 4. In the first state, the location of the opening portion 22h of the opening-degree adjusting valve 22e coincides with that of a region between one end portion of the side wall 22f and the partition wall 22g. In this case, the opening degree of the heat-medium flow adjusting valve 22 is set such that the FCU opening degree is 100% and the bypass opening degree is 0%. That is, the flow rate of water that flows out through the first outflow port 22b is 100% of the flow rate of water that flows into the inflow port 22a.

FIG. 6 is a top cross-sectional view schematically illustrating a second state of the heat-medium flow adjusting valve 22 as illustrated in FIG. 4. The second state is a state to which the state of the opening-degree adjusting valve 22e is changed from the first state when the opening-degree adjusting valve 22e is rotated from the position thereof in the first state in a clockwise direction such that the opening portion 22h of the opening-degree adjusting valve 22e faces the partition wall 22g. In this case, the opening degree of the heat-medium flow adjusting valve 22 is set such that the FCU opening degree is X % and the bypass opening degree is (100−X) %. That is, the flow rate of water that flows out through the first outflow port 22b is X % of the flow rate of water that flows into the inflow port 22a. Furthermore, the flow rate of water that flows out through the second outflow port 22c is (100−X) % of the flow rate of water that flows into the inflow port 22a.

FIG. 7 is a top cross-sectional view schematically illustrating a third state of the heat-medium flow adjusting valve 22 as illustrated in FIG. 4. The third state is a state to which the state of the opening-degree adjusting valve 22e is changed from the second state when the opening-degree adjusting valve 22e is rotated from the position thereof in the second state in the clockwise direction, and in which the location of the opening portion 22h of the opening-degree adjusting valve 22e coincides with that of a region between the partition wall 22g and the other end portion of the side wall 22f. In this case, the opening degree of the heat-medium flow adjusting valve 22 is set such that the FCU opening degree is 0% and the bypass opening degree is X %. That is, the flow rate of water that flows out through the second outflow port 22c is 100% of the flow rate of water that flows into the inflow port 22a.

FIG. 8 is a top cross-sectional view schematically illustrating a fourth state of the heat-medium flow adjusting valve 22 as illustrated in FIG. 4. The fourth state is a state to which the state of the opening-degree adjusting valve 22e is changed from the third state when the opening-degree adjusting valve 22e is rotated from the position thereof in the third state in the clockwise direction, and the opening portion 22h of the opening-degree adjusting valve 22e faces the other end portion of the side wall 22f. In this case, the opening degree of the heat-medium flow adjusting valve 22 is set such that the FCU opening degree is 0% and the bypass opening degree is X %. That is, the flow rate of water that flows out through the second outflow port 22c is X % of the flow rate of water that flows into the inflow port 22a.

FIG. 9 is a top cross-sectional view schematically illustrating a fifth state of the heat-medium flow adjusting valve 22 as illustrated in FIG. 4. The fifth state is a state to which the state of the opening-degree adjusting valve 22e is changed from the fourth state when the opening-degree adjusting valve 22e is rotated from the position thereof in the fourth state in the clockwise direction, and in which the location of the opening portion 22h of the opening-degree adjusting valve 22e coincides with that of a region between the above one end portion and the other end portion of the side wall 22f. In this case, the opening degree of the heat-medium flow adjusting valve 22 is set such that the FCU opening degree is 0% and the bypass opening degree is 0%. That is, water that flows into the inflow port 22a is completely blocked, that is, completely inhibited from flowing out. For example, when space where an indoor unit 2 including a FCU 21 is installed does not need to be air-conditioned, the flow of water to the indoor unit 2 is blocked by setting the opening degree of the heat-medium flow adjusting valve 22 as illustrated in FIG. 9. Therefore, the load on the pump 33 can be reduced.

FIG. 10 is a top cross-sectional view schematically illustrating a sixth state of the heat-medium flow adjusting valve 22 as illustrated in FIG. 4. The sixth state is a state to which the state of the opening-degree adjusting valve 22e is changed from the fifth state when the opening-degree adjusting valve 22e is rotated from the position thereof in the fifth state in the clockwise direction, and in which the opening portion 22h of the opening-degree adjusting valve 22e face the above one end portion of the side wall 22f. In this case, the opening degree of the heat-medium flow adjusting valve 22 is set such that the FCU opening degree is X % and the bypass opening degree is 0%. That is, the flow rate of water that flows out through the first outflow port 22b is X % of the flow rate of water that flows into the inflow port 22a.

In the above manner, the heat-medium flow adjusting valve 22 is controlled in opening degree, thereby allowing water that has flowed into the inflow port 22a to flow out from both the first outflow port 22b and the second outflow port 22c at a controlled flow rate.

[Operation of Air-Conditioning Apparatus 100]

Next, the operation of the air-conditioning apparatus 100 having the above configuration will be described. In the following explanation, the flow of water serving as a heat medium that circulates in the heat medium circuit and a flow-rate control process in the indoor unit 2a to 2c are described.

(Flow of heat medium)

FIG. 11 is a schematic view for explaining the flow of a heat medium. Referring to FIG. 11, three indoor units 2 are connected in series in the air-conditioning apparatus 100. It should be noted that a group including the indoor units 2 connected in series will be referred to as “system”. That is, the air-conditioning apparatus 100 as illustrated in FIG. 11 is configured such that a system #1 includes the indoor units 2a to 2c connected in series, and the system #1 is connected parallel to the relay unit 3.

In the indoor unit 2a of the system #1, water that has flowed into the indoor unit 2a flows through an FCU 21a or the indoor-side bypass pipe 23 at a flow rate that depends on the set opening degree of the heat-medium flow adjusting valve 22. The water that has flowed into the FCU 21a exchanges heat with indoor air to receive heat from or transfer heat to the indoor air, thereby cooling or heating the indoor air, and the water then flows out from the FCU 21a. The water that has flowed out of the FCU 21a and the water that has flowed through the indoor-side bypass pipe 23 joins each other at a location downward of the FCU 21a, and flows into the indoor unit 2b that is provided downstream of the indoor unit 2a.

In the indoor unit 2b, the water that has flowed into the indoor unit 2b flows through an FCU 21b or the indoor-side bypass pipe 23 at a flow rate that depends on the set opening degree of the heat-medium flow adjusting valve 22. The water that has flowed into the FCU 21b exchanges heat with indoor air to receive heat from or transfer heat to the indoor air, thereby cooling or heating the indoor air, and the water then flows out of the FCU 21b. The water that has flowed out of the FCU 21b and the water that flows in the indoor-side bypass pipe 23 join each other at a location downstream of the FCU 21b, and flow into the indoor unit 2c that is provided downstream of the indoor unit 2b.

In the indoor unit 2c, the water that has flowed into the indoor unit 2c flows through an FCU 21c or the indoor-side bypass pipe 23 at a flow rate that depends on the set opening degree of the heat-medium flow adjusting valve 22. The water that has flowed into the FCU 21c exchanges heat with indoor air to receive heat from or transfer heat to the indoor air, thereby cooling or heating the indoor, and the water then flows out of the FCU 21c. The water that has flowed out of the FCU 21c and the water that flows in the indoor-side bypass pipe 23 join each other at a location downstream of the FCU 21c, and then flow out of the indoor unit 2c.

The water that has flowed out of the indoor unit 2c flows into the relay unit 3 through the heat medium pipe 20. The water that has flowed into the relay unit 3 flows into the intermediate heat exchanger 32 via the pump 33. Thereafter, the above circulation is repeated.

(Flow-Rate Control Process)

The following description is made regarding a flow-rate control process of adjusting the flow rate of water that flows into the FCU 21 of each of the indoor units 2a to 2c. When water flows into the FCU 21 at a rate such that the water causes an air conditioning performance to be higher than a required FCU performance, heat of water cannot be fully used, and heat remains in water that has passed through the FCU 21. Therefore, a heat usage efficiency for transfer power is reduced.

In view of the above, in Embodiment 1, the air-conditioning apparatus 100 performs the flow-rate control process of adjusting the flow rate of water for each FCU 21 in the system #1 to cause water to flow into each FCU 21 at a required flow rate. In the flow-rate control process, the opening degrees of the heat-medium flow adjusting valves 22 that are associated with the respective FCUs 21 are controlled to adjust the flow rates of water for the FCUs 21.

The flow rate of water that flows into the FCU 21 can be calculated based on the difference between the pressure of water before passage of the water through the heat-medium flow adjusting valve 22 and that after passage of the water through the heat-medium flow adjusting valve 22 and a Cv value indicating characteristics of the heat-medium flow adjusting valve 22. The Cv value is a value determined based on the type of the heat-medium flow adjusting valve 22 and the diameter of a port of the heat-medium flow adjusting valve 22, and is a capacity coefficient of the heat-medium flow adjusting valve 22. The Cv value is a numerical value indicating the flow rate of a fluid that passes through the heat-medium flow adjusting valve 22 at a certain differential pressure. The flow rate of water increases as the Cv value increases. The flow rate of water decreases as the Cv value decreases.

The FCU performance calculation unit 41 calculates FCU performance that the FCUs 21 in the system #1 are currently required to achieve. The FCU performance of each FCU 21 is calculated based on formula (1) using set FCU performance set in advance for each FCU 21, an inlet temperature of water that flows into the FCU 21, an outlet temperature of water that flows out of the FCU 21, and the temperature of indoor air sucked by the fan 122.

FCU performance=set FCU performance×(outlet/inlet temperature difference/set outlet/inlet temperature difference)×(water/air temperature difference/set water/air temperature difference) (1)

In formula (1), the outlet/inlet temperature difference is the temperature difference between a current outlet temperature of water that flows out of the FCU 21 and a current inlet temperature of water that flows into the FCU 21. The water/air temperature difference is the temperature difference between a current temperature of air that is sucked into the FCU 21 and a current inlet temperature of water that flows into the FCU 21.

Next, the valve opening-degree determination unit 42 determines, as a representative FCU of the system #1, a FCU 21 having the highest calculated FCU performance among the FCUs 21 in the system #1. Then, the valve opening-degree determination unit 42 determines the opening degree of the heat-medium flow adjusting valve 22 that is associated with the representative FCU such that the opening degree is set to the opening degree of the heat-medium flow adjusting valve 22 opened such that the heat-medium flow adjusting valve 22 is fully opened toward the FCU 21. The valve opening-degree determination unit 42 also determines the opening degrees of the heat-medium flow adjusting valves 22 that are associated with the FCUs 21 other than the representative FCU based on the ratios of the performance of the FCUs 21 other than the representative FCU to that of the representative FCU.

FIG. 12 is a schematic view illustrating the opening degrees of the heat-medium flow adjusting valves 22 that are associated with the FCUs 21a to 21c of the system #1 as illustrated in FIG. 11. The FCU number indicated in FIG. 12 is a number assigned to each FCU 21 in the system #1. In the figure, reference sings denoting the respective FCUs 21 in the system #1 are indicated; the FCU performance is the FCU performance of each FCU 21; and the opening degree of the heat-medium flow adjusting valve is the opening degree of each of the heat-medium flow adjusting valves 22 that are associated with the respective FCUs 21, and the opening degrees for the FCU 21 and for the indoor-side bypass pipe 23 are also indicated.

As illustrated in FIG. 12, of the FCU performance of the FCUs 21a to 21c in the system #1, the FCU performance of the FCU 21c is 5 kW, which is the highest FCU performance in the system #1. Therefore, the valve opening-degree determination unit 42 determines the FCU 21c as the representative FCU of the system #1. Then, the valve opening-degree determination unit 42 sets the FCU opening degree of the heat-medium flow adjusting valve 22 that is associated with the FCU 21c to 100%, which is the opening degree of the valve opening-degree determination unit 42 opened such that the heat-medium flow adjusting valve 22 is fully opened toward the FCU 21c.

On the other hand, the FCU performance of each of the FCU 21a and the FCU 21b is 1 kW, which is ⅕ of the FCU performance of the FCU 21c. Therefore, based on the performance ratio of the FCU performance of each of the FCU 21a and 21b to that of the FCU 21c, the valve opening-degree determination unit 42 determines that the FCU opening degrees of the heat-medium flow adjusting valves 22 that are associated with the respective FCUs 21a and 21b are 20% (=100% x⅕), and the bypass opening degrees of the heat-medium flow adjusting valves 22 are 80%.

The following description is made with respect to the case where any of the FCUs 21 in the system #1 is made to be in a thermo-off state or the case where the FCU performance of the FCU 21 varies. The case where the FCU 21 is made to be in the thermo-off state is the case where the fan 122 of the FCU 21 is stopped. To be more specific, for example, when an indoor temperature exceeds the set temperature during heating operation, or when an indoor temperature falls below the set temperature during cooling operation, the FCU 21 is made to be in the thermo-off state. When the FCU 21 is made to be in the thermo-off state or when the FCU performance varies, the controller 4 controls the opening degree of the heat-medium flow adjusting valve 22 in accordance with the thermo-off state or the variation of FCU performance.

FIG. 13 is a schematic view indicating the opening degrees of the heat-medium flow adjusting valves 22 in the case where the FCU 21b is made to be in the thermo-off state. FIG. 14 is a schematic view indicating the opening degrees of the heat-medium flow adjusting valves 22 in the case where the FCU performance of the FCU 21c, which is the representative FCU, varies.

When the FCU 21b is made to be in the thermo-off state, it is unnecessary to cause water to flow into the FCU 21b. Therefore, as indicated in FIG. 13, the valve opening-degree determination unit 42 determines the FCU opening degree of the heat-medium flow adjusting valve 22 associated with the FCU 21b as 0%, and determines that the bypass opening degree of the heat-medium flow adjusting valve 22 as 100%. In this case, the FCU performance of the FCU 21c, which is the representative FCU, does not vary, and only the opening degree of the heat-medium flow adjusting valve 22 associated with the FCU 21b, which is made to be in the thermo-off state, is changed.

By contrast, when the FCU performance of the FCU 21c, which is the representative FCU, varies, the performance ratio of the FCU performance of the FCU 21a to that of the FCU 21c and the performance ratio of the FCU performance of the FCU 21b to that of the FCU 21c vary. In the example indicated in FIG. 14, the FCU performance of the FCU 21c, which is the representative FCU, varies from 5 to 3 kW, and as a result at that time, the FCU performance of the FCU 21a and the FCU performance of the FCU 21b are ⅓ of the FCU performance of the FCU 21c.

Therefore, the valve opening-degree determination unit 42 determines the FCU opening degrees of the heat-medium flow adjusting valves 22 associated with the FCU 21a and the FCU 21b as 33% (≈100%×⅓), and determines the bypass opening degrees of the heat-medium flow adjusting valves 22 as 67%. As described above, when the FCU performance of the FCU 21c, which is the representative FCU, varies, the opening degrees of the heat-medium flow adjusting valves 22 associated with the FCU 21a and the FCU 21b, which are FCUs other than the representative FCU, are changed.

In this example, the FCU performance that the FCU is currently required to achieved is used as the FCU performance for controlling the opening degree of the heat-medium flow adjusting valve 22. This, however, is not limiting. For example, a set FCU performance determined in advance for each FCU 21 may be used without any change. In this case, it is not necessary to calculate FCU performance that the FCUs 21 are required to currently achieve, and it is therefore possible to simplify the configuration related to the control of the opening degrees of the heat-medium flow adjusting valves 22.

As described above, in Embodiment 1, the representative FCU in the system is determined, and in accordance with the performance ratio between the FCU performance of the representative FCU and the FCU performance of each of the FCUs 21 other than the representative FCU, the opening degree of the heat-medium flow adjusting valve 22 associated with each FCU is determined. Thus, water flows into each FCU 21 at a required rate, and heat of water can be efficiently used.

In this example, the representative FCU of each system is determined based on FCU performance of the FCUs 21. This, however, is not limiting. For example, the representative FCU of each system may be determined in advance. In the case where the representative FCU is determined in advance, as described above, the indoor-side bypass pipe 23 of the indoor unit 2 that is associated with the representative FCU can be omitted. Furthermore, in an indoor unit 2 from which the indoor-side bypass pipe 23 is omitted, the heat-medium flow adjusting valve 22 does not need to have a plurality of outflow ports, and has only to have a function of adjusting the flow rate of water that flows into the heat-medium flow adjusting valve 22 and then causing the water to flow out therefrom.

As described above, in the air-conditioning apparatus 100 according to Embodiment 1, the indoor units 2 that include respective indoor-side bypass pipe 23 are connected in series. A heat medium subjected to heat exchange with indoor air is caused to flow into the heat exchangers connected in series. Thus, since heat of the heat medium is used by the plurality of indoor units 2, the amount of residual heat of the heat medium can be reduced. In the case where the heat medium is water, a phase change in the heat medium circuit is small, and a change in temperature of the heat medium is smaller than that of refrigerant. Thus, the plurality of indoor units 2 can be connected in series.

Each of the indoor units 2a to 2c includes the heat-medium flow adjusting valve 22 that can control the flow rate, the use-side heat exchanger 121 connected with the first outflow port 22b of the heat-medium flow adjusting valve 22, and the indoor-side bypass pipe 23 connected with the second outflow port 22c of the heat-medium flow adjusting valve 22. Furthermore, in the air-conditioning apparatus 100, the indoor units 2 are connected in series. Thus, since a necessary amount of water flows into the FCU 21, and heat of water can be efficiently used.

Furthermore, the air-conditioning apparatus 100 includes the controller 4 that controls the opening degrees of the heat-medium flow adjusting valves 22 based on the performance of the respective FCUs 21 of the indoor units 2a to 2c. The controller 4 includes the valve opening-degree determination unit 42 that controls the opening degrees of the heat-medium flow adjusting valves 22 based on the performance ratios between the FCU performance of the representative FCU having the highest CPU performance among the FCU performances of the FCUs 21 of the indoor units 2 and the FCU performance of the other FCUs 21. Thus, it is possible to supply a necessary amount of water to each of the FCUs 21.

Furthermore, the controller 4 also includes the FCU performance calculation unit 41 that calculates the FCU performance of each of the plurality of the FCUs 21 based on a temperature at the inlet of each FCU 21, a temperature at the outlet thereof, and the temperature of air sucked into the FCU 21. It is therefore possible to calculate the FCU performance that each of the FCUs 21 is currently required to achieve.

Embodiment 2

Next, an air-conditioning apparatus according to Embodiment 2 of the present disclosure will be described. In Embodiment 2, the system #1 including the indoor units 2a to 2c connected in series and a system #2 including a plurality of indoor units 2d to 2f connected in series are connected parallel to each other. In this regard, Embodiment 2 is different from Embodiment 1. Regarding Embodiment 2, components that are the same as those in Embodiment 1 will be denoted by the same reference signs, and their detailed descriptions will thus be omitted.

[Configuration of Air-Conditioning Apparatus 200]

FIG. 15 is a schematic view illustrating an example of the configuration of an air-conditioning apparatus 200 according to Embodiment 2. As illustrated in FIG. 15, the air-conditioning apparatus 200 includes the outdoor unit 1, the plurality of indoor units 2a to 2f, and the relay unit 3. The outdoor unit 1 and the relay unit 3 are connected by the refrigerant pipe 10, whereby a refrigerant circuit is formed. The indoor units 2a to 2f and the relay unit 3 are connected by the heat medium pipe 20, whereby a heat medium circuit is formed. The indoor units 2a to 2c are connected in series, thus forming the system #1. The indoor units 2d to 2f are connected in series, thus forming the system #2. The indoor units 2a to 2c of the system #1 and the indoor units 2d to 2f of the system #2 are connected in parallel.

[Operation of Air-Conditioning Apparatus 200]

Next, the operation of the air-conditioning apparatus 200 having the above configuration will be described. The following description is made with respect to the flow of water serving as a heat medium that circulates in the heat medium circuit. The flow-rate control process in the indoor unit 2a to 2f is the same as that in Embodiment 1, and its description will thus be omitted.

(Flow of Heat Medium)

Referring to FIG. 15, in the air-conditioning apparatus 200, the system #1 including the indoor units 2a to 2c connected in series and the system #2 including the indoor units 2d to 2f connected in series are connected parallel to the relay unit 3.

In the relay unit 3, water that has flowed out from the intermediate heat exchanger 32 flows out of the relay unit 3 through the heat medium pipe 20. The water that has flowed out of the relay unit 3 branches off and flows into two systems #1 and #2. The water flows into the indoor unit 2a, which is the indoor unit located at the most upstream side in the system #1, and also into the indoor unit 2d, which is the indoor unit located on the most upstream side in the system #2. The flow of water in the system #1 is the same as that of Embodiment 1, and its description will thus be omitted.

In the indoor unit 2d of the system #2, the water that has flowed into the indoor unit 2d flows through the FCU 21d or an indoor-side bypass pipe 23 of the indoor unit 2d at a flow rate that depends on the set opening degree of the heat-medium flow adjusting valve 22. The water that has flowed into the FCU 21d exchanges heat with indoor air to receive or transfer heat, thereby cooling or heating the indoor air, and the water then flows out of the FCU 21d. The water that has flowed out of the FCU 21d and the water that flows through the indoor-side bypass pipe 23 joins each other at a location downstream of the FCU 21d, and flows into the indoor unit 2e, which is an indoor unit located downstream of the indoor unit 2d.

In the indoor unit 23e, the water that has flowed into the indoor unit 2e flows through an FCU 21e or an indoor-side bypass pipe 23 of the indoor unit 2e at a flow rate that depends on the set opening degree of the heat-medium flow adjusting valve 22. The water that has flowed into the FCU 21e exchanges heat with indoor air to receiver or transfer heat from or to the indoor air, thereby cooling or heating the indoor air, and the water then flows out of the FCU 21e. The water that has flowed out of the FCU 21e and the water that flows through the indoor-side bypass pipe 23 join each other at a location downstream of the FCU 21e, and flows into the indoor unit 2f, which is an indoor unit located downstream of the indoor unit 2e.

In the indoor unit 2f, the water that has flowed into the indoor unit 2f flows through an FCU 21f or an indoor-side bypass pipe 23 of the indoor unit 2f at a flow rate that depends on the set opening degree of the heat-medium flow adjusting valve 22. The water that has flowed into the FCU 21f exchanges heat with indoor air to receive or transfer heat from or to the indoor air, thereby cooling or heating the indoor air, and the water flows out of the FCU 21f. The water that has flowed out of the FCU 21f and the water that flows through the indoor-side bypass pipe 23 join each other at a location downstream of the FCU 21f, and flows out of the indoor unit 2f.

The water that has flowed out of the indoor unit 2c, which is the indoor unit located on the most downstream side in the system #1, and the water that has flowed out of the indoor unit 2f, which is the indoor unit located on the most downstream side in the system #2, join each other, and flow into the relay unit 3 through the heat medium pipe 20. The water that has flowed into the relay unit 3 flows into the intermediate heat exchanger 32 via the pump 33. Thereafter, the above circulation is repeated.

As described above, the air-conditioning apparatus 200 according to Embodiment 2 includes the plurality of systems each of which includes the plurality of indoor units 2 connected in series, and the plurality of systems are connected in parallel. Even in the case where the plurality of systems, each of which includes the plurality of indoor units 2 connected in series, are provided in the above manner, a necessary amount of water flows into each of the FCUs 21, and heat of water can be efficiently used, as in Embodiment 1.

Embodiment 3

Next, an air-conditioning apparatus according to Embodiment 3 of the present disclosure will be described. In Embodiment 3, the system #1 including the indoor units 2a to 2c connected in series, the system #2 including the plurality of indoor units 2d to 2f connected in series, and a system #3 including a plurality of indoor units 2g to 2i connected in series are connected in parallel. In this regard, Embodiment 3 is different from Embodiments 1 and 2. Regarding Embodiment 3, components that are the same as those in any of Embodiments 1 and 2 will be denoted by the same reference signs, and their detailed descriptions will thus be omitted.

[Configuration of Air-Conditioning Apparatus 300]

FIG. 16 is a schematic view illustrating an example of the configuration of an air-conditioning apparatus 300 according to Embodiment 3. As illustrated in FIG. 16, the air-conditioning apparatus 300 includes the outdoor unit 1, the plurality of indoor units 2a to 2i, and the relay unit 3. The outdoor unit 1 and the relay unit 3 are connected by the refrigerant pipe 10, whereby a refrigerant circuit is formed. The plurality of indoor units 2a to 2i and the relay unit 3 are connected by the heat medium pipe 20, whereby a heat medium circuit is formed. Furthermore, the indoor units 2a to 2c are connected in series, thus forming the system #1. The indoor units 2d to 2f are connected in series, thus forming the system #2. The indoor units 2g to 2i are connected in series, thus forming the system #3. The indoor units 2a to 2c of the system #1, the indoor units 2d to 2f of the system #2, and the indoor units 2g to 2i of the system #3 are connected in parallel.

[Operation of Air-Conditioning Apparatus 300]

Next, the operation of the air-conditioning apparatus 300 having the above configuration will be described. The following description is made with respect to the flow of water serving as a heat medium that circulates through the heat medium circuit and the control of the flow rate of water for each of the systems #1 to #3.

(Flow of Heat Medium)

Referring to FIG. 16, in the air-conditioning apparatus 300, the system #1 including the indoor units 2a to 2c connected in series, the system #2 including the indoor units 2d to 2f connected in series, the system #3 including the indoor units 2g to 2i connected in series are connected parallel to the relay unit 3.

In the relay unit 3, water that has flowed out of the intermediate heat exchanger 32 flows out of the relay unit 3 through the heat medium pipe 20. The water that has flowed out of the relay unit 3 branches off and flows into three systems #1 to #3. The water flows into the indoor unit 2a, which is the indoor unit located on the most upstream side in the system #1, into the indoor unit 2d, which is the indoor unit located on the most upstream side in the system #2, and into the indoor unit 2g, which is the indoor unit located on the most upstream side in the system #3. The flow of water in the systems #1 and #2 is the same as that in Embodiment 2, and its description will thus be omitted.

In the indoor unit 2g of the system #3, the water that has flowed into the indoor unit 2g flows through an FCU 21g or an indoor-side bypass pipe 23 of the indoor unit 2g at a flow rate that depends on the set opening degree of the heat-medium flow adjusting valve 22. The water that has flowed into the FCU 21g exchanges heat with indoor air to receive or transfer heat from or to the indoor air, thereby cooling or heating the indoor air, and the water flows out of the FCU 21g. The water that has flowed out of the FCU 21g and the water that flows through the indoor-side bypass pipe 23 join each other at a location downstream of the FCU 21g, and flow into the indoor unit 2h, which is the indoor unit located downstream of the indoor unit 2g.

In the indoor unit 2, the water that has flowed into the indoor unit 2h flows through an FCU 21h or an indoor-side bypass pipe 23 of the indoor unit 2h at a flow rate that depends on the set opening degree of the heat-medium flow adjusting valve 22. The water that has flowed into the FCU 21h exchanges heat with indoor air to receive or transfer heat from or to the indoor air, thereby cooling or heating the indoor air, and the water flows out of the FCU 21h. The water that has flowed out of the FCU 21h and the water that flows through the indoor-side bypass pipe 23 join each other at a location downstream of the FCU 21h, and flow into the indoor unit 2i, which is the indoor unit located downstream of the indoor unit 2h.

In the indoor unit 2i, the water that has flowed into the indoor unit 2i flows through an FCU 21i or an indoor-side bypass pipe 23 of the FCU 21i at a flow rate that depends on the set opening degree of the heat-medium flow adjusting valve 22. The water that has flowed into the FCU 21i exchanges heat with indoor air to receive or transfer heat from or to the indoor air, thereby cooling or heating the indoor air, and the water flows out of the FCU 21i. The water that has flowed out of the FCU 21i and the water that flows through the indoor-side bypass pipe 23 join each other at a location downstream of the FCU 21i, and flow out of the indoor unit 2i.

The water that has flowed out of the indoor unit 2c, which is the indoor unit located on the most downstream side in the system #1, the water that has flowed out of the indoor unit 2f, which is the indoor unit located on the most downstream side in the system #2, and the water that has flowed out of the indoor unit 2i, which is the indoor unit located on the most downstream side in the system #3, join together, and flow into the relay unit 3 through the heat medium pipe 20. The water that has flowed into the relay unit 3 flows into the intermediate heat exchanger 32 via the pump 33. Thereafter, the above circulation is repeated.

(Control of Flow Rates of Water for Systems #1 to #3)

Next, the control of the flow rates of water for the systems #1 to #3 will be described. The following is made with respect to the control of the flow rates of water in the case where the representative FCUs in the systems #1 to #3 have different FCU performance. FIGS. 17 to 20 are schematic views indicating the opening degrees of the heat-medium flow adjusting valves 22 in the case where the representative FCUs in the respective systems #1 to #3 have different FCU performance. In FIGS. 17 to 20, the FCUs 21 indicated by bold lines are the representative FCUs in the systems #1 to #3.

FIG. 17 is a schematic view indicating a first example of the opening degrees of the heat-medium flow adjusting valves in the case where the representative FCUs in the systems #1 to #3 have different FCU performance. The first example indicated in FIG. 17 is an example in which the FCU opening degree of the heat-medium flow adjusting valve 22 that depends on the representative FCU in each of all systems #1 to #3 is set to 100% regardless of the FCU performance of the representative FCU.

In the first example, the representative FCUs of the systems #1 to #3 are the FCUs 21c, 21e and 21g, respectively. Therefore, the heat-medium flow adjusting valves 22 associated with the FCUs 21c, 21e and 21g are set as illustrated in FIG. 5. In this case, water flows equally in the systems #1 to #3, and the FCU opening degree of the heat-medium flow adjusting valve 22 that depends on the representative FCU of each of the systems #1 to #3 is 100%. It is therefore possible to simplify the control of the heat-medium flow adjusting valves 22 associated with the representative FCUs.

In this example, the representative FCU of the system #2 has the highest FCU performance, and in the systems #1 and #3, water flows at a flow rate equivalent to that in the system #2. Therefore, the performance of each of the systems #1 and #3 is excessively high, and thus an indoor space may be excessively cooled or heated. Thus, in this case, it is appropriate that the FCU in each of the systems #1 and #3 is made to be in the thermos-off state, to thereby prevent excessive cooling or excessive heating.

To be more specific, the valve opening-degree determination unit 42 sets the bypass opening degree of the heat-medium flow adjusting valve 22 associated with the FCU 21a in the system #1 to 100%, and causes the FCU 21a to be in the thermo-off state. Furthermore, the valve opening-degree determination unit 42 sets the bypass opening degree of the heat-medium flow adjusting valve 22 associated with the FCU 21i in the system #3 to 100%, and causes the FCU 21i to be in the thermo-off state.

FIG. 18 is a schematic view illustrating a second example of the opening degrees of the heat-medium flow adjusting valves in the case where the representative FCUs of systems #1 to #3 have difference FCU performance. The second example indicated in FIG. 18 is an example in which in order to reduce excessively high performance in the first example, expansion devices for controlling the flow rate are provided at respective positions immediately after the heat medium pipes in the respective systems #1 to #3 branch off, that is, on the most upstream sides of the respective systems #1 to #3. Thus, a necessary amount of water for each of the systems #1 to #3 is supplied to each system.

In the second example, the FCU performance of the FCU 21e, which is the representative FCU of the system #2, is 7 kW, and the FCU 21e has the highest FCU performance. Thus, the controller 4 sets the opening degree of the expansion device of the system #2 such that the expansion device of the system #2 is made to be in a fully opened state, and determines the opening degrees of the expansion devices of the systems #1 and #3 based on the FCU performance of the representative FCU of the system #2. In this case, the FCU performance of the FCU 21c, which is the representative FCU of the system #1, is 5 kW, and the opening degree of the expansion device of the system #1 is thus determined as 71% (≈5 kW/7 kW×100%). The FCU performance of the FCU 21g, which is the representative FCU of the system #3, is 4 kW and the opening degree of the expansion device of the system #3 is thus determined as 57% (≈4 kW/7 kW×100%).

In the case where a FCU 21 to be caused to be in the thermo-off state is present in a system, the heat-medium flow adjusting valve 22 associated with the FCU 21 may be set as illustrated in FIG. 8. That is, the FCU opening degree of the heat-medium flow adjusting valve 22 is set to 0%, and the bypass opening degree is set to the set opening degree. When the opening degree of the heat-medium flow adjusting valve 22 is set as illustrated in FIG. 8, the heat-medium flow adjusting valve 22 serves as an expansion device, whereby the flow rate of water that flows into the FCUs 21 following the above associated FCU 21 is controlled. Therefore, the flow rate of water that flows through each of the systems #1 to #3 can be controlled without providing the expansion devices described above.

FIG. 19 is a schematic view illustrating a third example of the opening degrees of the heat-medium flow adjusting valves in the case where the representative FCUs in the respective systems #1 to #3 have difference FCU performance. The third example indicated in FIG. 19 is an example in which the heat-medium flow adjusting valves 22 associated with the representative FCUs in the systems #1 to #3 are made to have different FCU opening degrees in accordance with the FCU performance of the representative FCUs.

In the third example, the FCU opening degree of the heat-medium flow adjusting valve 22 associated with the representative FCU having the highest FCU performance among the FCU performances of the representative FCUs in the respective systems #1 to #3 is determined as 100%. The FCU opening degrees of the heat-medium flow adjusting valves 22 associated with the representative FCUs other than the above representative FCU are determined based on respective performance ratios.

More specifically, the FCU performance of the FCU 21e, which is the representative FCU of the system #2, is 7 kW and the highest in the FCUs. Thus, the controller 4 sets the FCU opening degree of the heat-medium flow adjusting valve 22 associated with the representative FCU of the system #2 to 100%. Then, the controller 4 determines the FCU opening degrees of the heat-medium flow adjusting valves 22 associated with the representative FCUs of the systems #1 and #3 based on the respective ratios of the FCU performance of the representative FCUs to the above set FCU opening degree of the heat-medium flow adjusting valve 22.

In this case, the FCU performance of the FCU 21c, which is the representative FCU of the system #1, is 5 kW. Therefore, based on the performance ratio between the FCU performance of the FCU 21c and the FCU performance of the representative FCU in the system #2, it is determined that the FCU opening degree of the heat-medium flow adjusting valve 22 associated with the representative FCU of the system #1 is 71% (≈5 kW/7 kW×100%). The FCU performance of the FCU 21g, which is the representative FCU of the system #3, is 4 kW. Therefore, based on the performance ratio between the FCU performance of the FCU 21g and the FCU performance of the representative FCU in the system #2, it is determined that the FCU opening degree of the heat-medium flow adjusting valve 22 associated with the representative FCU of the system #3 is 57% (≈4 kW/7 kW×100%).

As described above, by setting the opening degrees of the heat-medium flow adjusting valves 22 to different values based on the respective FCU performance of the representative FCUs of the respective systems #1 to #3, it is possible to perform a fine control such that air conditioning performance is controlled for respective air-conditioned spaces where the indoor units 2 of the systems #1 to #3 are provided. Furthermore, it is possible to reduce the flow rate of water into the FCU 21 at a flow rate higher than a required flow rate, and heat can be more efficiently used.

In the third example, the FCUs 21 can achieve required FCU performance, and the flow rates at which water flows through the respective systems #1 to #3 are equivalent to each other. Thus, water flows into each of the systems #1 and #3 at an excessively high flow rate.

FIG. 20 is a schematic view illustrating a fourth example of the opening degrees of the heat-medium flow adjusting valves in the case where the representative FCUs in the respective systems #1 to #3 have difference FCU performance. The fourth example indicated in FIG. 20 is an example where the opening degrees of the heat-medium flow adjusting valves 22 associated with the representative FCUs of the systems other than the system including the representative FCU having the highest performance are adjusted in order to reduce the flow rate of water that flows at an excessively high flow rate in the third example.

In the fourth example, as in the third example, the valve opening-degree determination unit 42 sets the FCU opening degree of the heat-medium flow adjusting valve 22 associated with the FCU 21e, which is the representative FCU of the system #2, to 100%. Furthermore, the valve opening-degree determination unit 42 sets the opening degrees of the heat-medium flow adjusting valves 22 associated with the FCU 21c and the FCU 21g, which are the representative FCUs of the systems #1 and #3 that are systems other than the system #2, as illustrated in FIG. 10. The opening degrees of the heat-medium flow adjusting valves 22 are set as illustrated in FIG. 10, whereby the flow rate of water that flows into the FCUs 21 following the above associated FCU 21 is adjusted.

That is, the FCU opening degrees of the heat-medium flow adjusting valves 22 associated with the representative FCUs of the systems #1 and #3 are set based on the ratio of the FCU performance of the representative FCU to the FCU opening degree of the heat-medium flow adjusting valve 22 associated with the representative FCU of the system #2. Furthermore, at this time, the bypass opening degrees of the heat-medium flow adjusting valves 22 are set to 0%.

More specifically, the heat-medium flow adjusting valve 22 associated with the FCU 21c, which is the representative FCU of the system #1, is set such that the FCU opening degree is 71% and the bypass opening degree is 0%. Furthermore, the heat-medium flow adjusting valve 22 associated with the FCU 21g, which is the representative FCU of the system #3, is set such that the FCU opening degree is 57% and the bypass opening degree is 0%.

As described above, the opening degrees of the heat-medium flow adjusting valves 22 are set such that the bypass opening degrees of the heat-medium flow adjusting valves 22 associated with the representative FCUs of the systems other than the system including the representative FCU having the highest performance are 0%, whereby the flow rates of water for the respective systems #1 to #3 can be adjusted.

As described above, in the air-conditioning apparatus 300 according to Embodiment 3, the valve opening-degree determination unit 42 sets the opening degrees of the heat-medium flow adjusting valves 22 associated with the representative FCUs of the respective systems such that the heat-medium flow adjusting valves 22 are made to be in the fully opened state. Furthermore, the valve opening-degree determination unit 42 determines the opening degrees of the heat-medium flow adjusting valves 22 associated with other FCUs based on the respective performance ratios. Therefore, it is possible to simplify the control of the opening degrees of the heat-medium flow adjusting valves 22 in the respective systems.

Moreover, the expansion devices are provided on the most upstream sides of the respective systems, and the controller 4 determines the opening degrees of the expansion devices of the respective systems based on the performance ratios of the representative FCUs of the respective systems. Therefore, it is possible to supply a required amount of water to each of the systems.

The valve opening-degree determination unit 42 sets the opening degree of the heat-medium flow adjusting valve 22 connected to the representative FCU having the highest FCU performance among the representative FCUs of all the systems such that the heat-medium flow adjusting valve 22 is made to be in the fully opened state. Furthermore, the valve opening-degree determination unit 42 determines the opening degree of the heat-medium flow adjusting valve 22 connected to another representative FCU based on the performance ratio of the FCU performance of the above other representative FCU to the FCU performance of the representative FCU having the highest performance. Then, the valve opening-degree determination unit 42 determines the opening degree of the heat-medium flow adjusting valve 22 associated with the above other representative FCU such that the heat-medium flow adjusting valve 22 allows the heat-medium outflow side of the other representative FCU to communicate with the second outflow port 22c. As a result, the flow rate of water for each system is appropriately set, and unnecessary transfer power can be reduced.

Embodiment 4

Next, an air-conditioning apparatus according to Embodiment 4 of the present disclosure will be described. In Embodiment 4, the indoor units 2a to 2i are provided with respective indoor-side controllers. In this regard, Embodiment 4 is different from Embodiments 1 to 3. Regarding Embodiment 4, components that are the same as those of any of Embodiments 1 to 3 will be denoted by the same reference signs, and their detailed descriptions will thus be omitted.

[Configuration of Air-Conditioning Apparatus 400]

FIG. 21 is a schematic view illustrating an example of the configuration of an air-conditioning apparatus 400 according to Embodiment 4. As illustrated in FIG. 21, the air-conditioning apparatus 400 includes the outdoor unit 1, the plurality of indoor units 2a to 2i, and the relay unit 3. The outdoor unit 1 and the relay unit 3 are connected by the refrigerant pipe 10, whereby a refrigerant circuit is formed. The plurality of indoor units 2a to 2i and the relay unit 3 are connected by the heat medium pipe 20, whereby a heat medium circuit is formed. The indoor units 2a to 2c are connected in series, thus forming the system #1. The indoor units 2d to 2f are connected in series, thus forming the system #2. The indoor units 2g to 2i are connected in series, thus forming the system #3. The indoor units 2a to 2c of the system #1, the indoor units 2d to 2f of the system #2, and the indoor units 2g to 2i of the system #3 are connected in parallel, respectively.

In Embodiment 4, as illustrated in FIG. 21, each of the indoor units 2a to 2i includes an indoor-side controller 27 in addition to the configuration as illustrated in FIG. 2. The indoor-side controller 27 controls components in an indoor unit 2 in which the indoor-side controller 27 is provided. Of various controls by the controller 4 of each of Embodiment 1 to 3, a control related to the indoor unit 2 in which the indoor-side controller 27 is provided is performed by the indoor-side controller 27. To be more specific, the indoor-side controller 27 controls calculation of the FCU performance of the FCU 21, the opening degree of the heat-medium flow adjusting valve 22 based on the calculated FCU performance, etc.

The indoor-side controller 27 communicates with indoor-side controllers 27 provided in the other indoor units 2 and with the controller 4 provided in the relay unit 3. For example, the indoor-side controllers 27 exchanges information with each other, which is, for example, information from sensors including the inlet temperature sensor 24, the outlet temperature sensor 25, the suction temperature sensor 26 and other sensors, and information related to the control of the opening degree of the heat-medium flow adjusting valve 22.

As described above, the indoor units 2a to 2i are provided with the respective indoor-side controllers 27, whereby it is possible to perform an interlocking control between the outdoor unit 1, the indoor units 2 and the relay unit 3. Furthermore, it is possible to easily replace each indoor unit 2 solely with a new one.

Embodiment 5

Next, an air-conditioning apparatus according to Embodiment 5 of the present disclosure will be described. In Embodiment 5, a cooling device and a heating device are provided in the air-conditioning apparatus. In this regard, Embodiment 4 is different from Embodiments 1 to 4. Regarding Embodiment 5, components that are the same as those in any of Embodiments 1 to 4 will be denoted by the same reference signs, and their detailed descriptions will thus be omitted.

[Configuration of Air-Conditioning Apparatus 500]

FIG. 22 is a schematic view illustrating an example of the configuration of an air-conditioning apparatus 500 according to Embodiment 5. As illustrated in FIG. 22, the air-conditioning apparatus 500 includes the outdoor unit 1, the indoor units 2a to 2c, the relay unit 3, a cooling device 5, and a heating device 6. The following description is made by referring to by way of example the case where the indoor units 2 form the system #1 only. This, however, is not limiting. The indoor units 2 may form a plurality of systems. Alternatively, the indoor units 2 may not be provided.

The outdoor unit 1 and the relay unit 3 are connected by the refrigerant pipe 10, whereby a refrigerant circuit is formed. The indoor units 2a to 2c, the cooling device 5, the heating device 6, and the relay unit 3 are connected by the heat medium pipe 20, whereby a heat medium circuit is formed. The indoor units 2a to 2c are connected in series, thus forming the system #1. The cooling device 5 and the heating device 6 are connected in series, thus forming a system #4. The indoor units 2a to 2c of the system #1 and the cooling device 5 and the heating device 6 of the system #4 are connected in parallel.

(Cooling Device 5)

The cooling device 5 is a device that generates cooling energy. For example, the cooling device 5 is provided in a room where heat is generated at all time, such as a refrigerator room, a freezer room, or a computer room. The cooling device 5 is provided to cool the inside of the room. The cooling device 5 includes a cooling-side intermediate heat exchanger 51, a cooling-side heat-medium flow adjusting valve 52, a compressor 53, an expansion valve 54, and a use-side heat exchanger 55.

The cooling-side intermediate heat exchanger 51 causes heat exchange to be performed between a heat medium that flows in the heat medium circuit connected with a heat-medium-side flow passage and cooling refrigerant that flows in the cooling refrigerant circuit connected with a refrigerant-side flow passage. The cooling-side intermediate heat exchanger 51 operates as a condenser that transfers heat of the cooling refrigerant to the heat medium to condense the cooling refrigerant.

The cooling-side heat-medium flow adjusting valve 52 is an electric three-way valve having an inflow port 52a, a first outflow port 52b, and a second outflow port 52c, and is provided on a water inflow side of the cooling-side intermediate heat exchanger 51. The cooling-side heat-medium flow adjusting valve 52 is provided to cause water that flows thereinto to branch off. In the cooling-side heat-medium flow adjusting valve 52, the first outflow port 52b is connected to the water inflow side of the cooling-side intermediate heat exchanger 51, and the second outflow port 52c is connected to the water outflow side of the cooling-side intermediate heat exchanger 51 by a cooling-side bypass pipe 50. Thus, the second outflow port 52c of the cooling-side heat-medium flow adjusting valve 52 and the water outflow side of the cooling-side intermediate heat exchanger 51 are connected.

The cooling-side heat-medium flow adjusting valve 52 has a configuration similar to that of the heat-medium flow adjusting valve 22. To be more specific, the opening degree of the cooling-side heat-medium flow adjusting valve 52 is controlled in opening degree by the controller 4 to allow water that has flowed into the inflow port 52a to flow out from both the first outflow port 52b and the second outflow port 52c at an adjusted flow rate.

In this example, the cooling-side bypass pipe 50 is provided in the cooling device 5. This, however, is not limiting. The cooling-side bypass pipe 50 may be provided outside the cooling device 5 and connected to the cooling device 5 by, for example, a connection fitting. Thus, the length of the cooling-side bypass pipe 50 is shortened, and it is therefore possible to reduce a loss caused by radiation of heat at the time when water flows through the pipe.

The compressor 53 sucks low-temperature, low-pressure cooling refrigerant, compresses the sucked refrigerant into high-temperature, high-pressure cooling refrigerant, and discharges the high-temperature, high-pressure refrigerant. The compressor 53 is, for example, an inverter compressor. The operating frequency of the compressor 53 is controlled by the controller 4.

The expansion valve 54 causes the cooling refrigerant to expand. The expansion valve 54 is a valve whose opening degree can be controlled by, for example, an electronic expansion valve. The opening degree of the expansion valve 54 is controlled by a controller of the cooling device 5 (not illustrated). The use-side heat exchanger 55 causes heat exchange to be performed between the cooling refrigerant and indoor air supplied by a fan (not illustrated). As a result, cooling air is generated as conditioned air to be supplied into an indoor space.

The cooling device 5 includes an inlet temperature sensor 56, an outlet temperature sensor 57, and a suction temperature sensor 58. The inlet temperature sensor 56 is provided on the water inflow side of the cooling-side intermediate heat exchanger 51 to detect the temperature of water that flows into the cooling-side intermediate heat exchanger 51. Also, the inlet temperature sensor 56 detects an inlet temperature of water in the system #4. The outlet temperature sensor 57 is provided on the water outflow side of the cooling-side intermediate heat exchanger 51 to detect the temperature of water that flows out of the cooling-side intermediate heat exchanger 51. The suction temperature sensor 58 is provided on an air suction side of the cooling-side intermediate heat exchanger 51 to detect the temperature of air that is sucked into the cooling-side intermediate heat exchanger 51.

(Heating Device 6)

The heating device 6 generates heating energy. For example, the heating device 6 is provided in a room that uses a radiant heating such as floor heating, or in a greenhouse for use in cultivation of a tropical plant, etc., or in a room where hot water is used, such as a kitchenette. The heating device 6 is provided to generate and store hot water. The heating device 6 includes a heating-side intermediate heat exchanger 61, a heating-side heat-medium flow adjusting valve 62, a compressor 63, an expansion valve 64, a water heat exchanger 65, a hot water storage tank 71, and a water supply pump 72.

The heating-side intermediate heat exchanger 61 causes heat exchange to be performed between a heat medium that flows in the heat medium circuit connected with the heat-medium-side flow passage and heating refrigerant that flows in the heating refrigerant circuit connected with the refrigerant-side flow passage. The heating-side intermediate heat exchanger 61 operates as an evaporator that evaporates the heating refrigerant to cool the heat medium by heat of vaporization that is produced when the heating refrigerant is evaporated.

The heating-side heat-medium flow adjusting valve 62 is an electric three-way valve having an inflow port 62a, a first outflow port 62b, and a second outflow port 62c, and is provided on the water inflow side of the heating-side intermediate heat exchanger 61. The heating-side heat-medium flow adjusting valve 62 is provided to cause water that flows thereinto to branch off. The first outflow port 62b of the heating-side heat-medium flow adjusting valve 62 is connected to the water inflow side of the heating-side intermediate heat exchanger 61. The second outflow port 62c is connected to the water outflow side of the heating-side intermediate heat exchanger 61 by a heating-side bypass pipe 60. Thus, the second outflow port 62c of the heating-side heat-medium flow adjusting valve 62 and the water outflow side of the heating-side intermediate heat exchanger 61 are connected.

The heating-side heat-medium flow adjusting valve 62 has a configuration similar to that of the heat-medium flow adjusting valve 22 and the cooling-side heat-medium flow adjusting valve 52. To be more specific, the heating-side heat-medium flow adjusting valve 62 is controlled in opening degree by the controller 4 to allow water that has flowed into the inflow port 62a to flow out from both the first outflow port 62b and the second outflow port 62c at an adjusted flow rate.

In this example, the heating-side bypass pipe 60 is provided in the heating device 6. This, however, is not limiting. The heating-side bypass pipe 60 may be provided outside the heating device 6 and connected to the heating device 6 by, for example, a connection fitting. Thus, the length of the heating-side bypass pipe 60 is shortened, and it is therefore possible to reduce a loss caused by, for example, radiation of heat at the time when water flows through the pipe.

The compressor 63 sucks low-temperature, low-pressure heating refrigerant, compresses the sucked refrigerant into high-temperature, high-pressure heating refrigerant, and discharges the high-temperature, high-pressure refrigerant. The compressor 63 is, for example, an inverter compressor. The operating frequency of the compressor 63 is controlled by the controller 4.

The expansion valve 64 causes the heating refrigerant to expand. The expansion valve 64 is a valve whose opening degree can be controlled by, for example, an electronic expansion valve. The opening degree of the expansion valve 64 is controlled by a controller of the heating device 6 (not illustrated). The water heat exchanger 65 causes heat exchange to be performed between heating refrigerant and a heat medium, for example, water that is stored in the hot water storage tank 71.

The hot water storage tank 71 stores water supplied from the outside. The hot water storage tank 71 has a water supply port and an outflow port that are located in a lower portion of the hot water storage tank 71, and also has an inflow port that is located in an upper portion of the hot water storage tank 71. Water is supplied to the hot water storage tank 71 from the outside through the water supply port, and the hot water storage tank 71 stores supplied unheated water. The unheated water stored in the hot water storage tank 71 flows out through the outflow port, and is supplied to the water heat exchanger 65.

The hot water storage tank 71 is supplied with water heated at the water heat exchanger 65 through the inflow port, and stores the supplied heated water. The heated water stored in the hot water storage tank 71 is discharged to the outside, and used as hot water for, for example, a shower.

The water supply pump 72 is driven by a motor (not illustrated), and supplies water that has flowed out of the hot water storage tank 71 to the water heat exchanger 65. The driving of the water supply pump 72 is controlled by a controller of the heating device 6 (not illustrated).

The heating device 6 includes an inlet temperature sensor 66, an outlet temperature sensor 67, and a heat medium temperature sensor 68. The inlet temperature sensor 66 is provided on the water inflow side of the heating-side intermediate heat exchanger 61 to detect the temperature of water that flows into the heating-side intermediate heat exchanger 61. The outlet temperature sensor 67 is provided on the water outflow side of the heating-side intermediate heat exchanger 61 to detect the temperature of water that flows out of the heating-side intermediate heat exchanger 61. Also, the outlet temperature sensor 67 detects an outlet temperature of water in the system #4. The heat medium temperature sensor 68 is provided close to the heating-side intermediate heat exchanger 61 to detect the temperature of the heat medium at a position close to the heating-side intermediate heat exchanger 61.

[Operation of Air-Conditioning Apparatus 500]

Next, the operation of the air-conditioning apparatus 500 having the above configuration will be described. The following description is made with respect to the flow of water that is a heat medium that circulates in the heat medium circuit. Referring to FIG. 22, in the air-conditioning apparatus 200, the system #1 includes the indoor units 2a to 2c connected in series, and the system #4 includes the cooling device 5 and the heating device 6 that are connected in series; and the system #1 and the system #4 are connected parallel to the relay unit 3.

In the relay unit 3, water that has flowed out of the intermediate heat exchanger 32 flows out of the relay unit 3 through the heat medium pipe 20. The water that has flowed out of the relay unit 3 branches off and flows into two systems #1 and #4, and then flows into the indoor unit 2a, which is located on the most upstream side in the system #1, and into the cooling device 5 in the system #4. The flow of water in the system #1 is the same as that in Embodiment 1, and its description will thus be omitted.

The water that has flowed into the cooling device 5 in the system #4 flows through the cooling-side intermediate heat exchanger 51 or the cooling-side bypass pipe 50 at a flow rate that depends on the set opening degree of the cooling-side heat-medium flow adjusting valve 52. The water that has flowed into the cooling-side intermediate heat exchanger 51 exchanges heat with the cooling refrigerant to cool the refrigerant, and flows out of the cooling-side intermediate heat exchanger 51. The water that has flowed out of the cooling-side intermediate heat exchanger 51 and the water that flows through the cooling-side bypass pipe 50 join each other at a location downstream of the cooling-side intermediate heat exchanger 51, and flow into the heating device 6, which is located downstream of the cooling device 5.

The water that has flowed into the heating device 6 flows through the heating-side intermediate heat exchanger 61 or the heating-side bypass pipe 60 at a flow rate that depends on the set opening degree of the heating-side heat-medium flow adjusting valve 62. The water that has flowed into the heating-side intermediate heat exchanger 61 exchanges heat with the heating refrigerant to heat the refrigerant, and flows out of the heating-side intermediate heat exchanger 61. The water that has flowed out of the heating-side intermediate heat exchanger 61 and the water that flows through the heating-side bypass pipe 60 join each other at a location downstream of the heating-side intermediate heat exchanger 61, and flow out of the heating device 6.

The water that has flowed out of the indoor unit 2c, which is located on the most downstream side in the system #1 and the water that has flowed out of the heating device 6 in the system #4 join each other, and then flow into the relay unit 3 through the heat medium pipe 20. The water that has flowed into the relay unit 3 flows into the intermediate heat exchanger 32 via the pump 33. Thereafter, the above circulation is repeated.

On the other hand, in the cooling device 5, the cooling refrigerant that flows through the cooling refrigerant circuit is compressed by compressor 53 and then discharged from the compressor 53. The cooling refrigerant discharged from the compressor 53 flows into the cooling-side intermediate heat exchanger 51. The cooling refrigerant that has flowed into the cooling-side intermediate heat exchanger 51 exchanges heat with water that flows through the heat medium circuit, and is condensed while transferring heat to the water to heat the water. Then, the cooling refrigerant flows out of the cooling-side intermediate heat exchanger 51

The cooling refrigerant that has flowed out of the cooling-side intermediate heat exchanger 51 is reduced in pressure and expanded by the expansion valve 54, and flows out of the expansion valve 54. The cooling refrigerant that has flowed out of the expansion valve 54 flows into the use-side heat exchanger 55. The cooling refrigerant that has flowed into the use-side heat exchanger 55 exchanges heat with indoor air to receive heat from the indoor air and evaporate, and then flows out of the use-side heat exchanger 55. The cooling refrigerant that has flowed out of the use-side heat exchanger 55 is sucked into the compressor 53. Thereafter, the cooling refrigerant repeats the above circulation.

In the heating device 6, the heating refrigerant that flows through the heating refrigerant circuit is compressed by the compressor 63 and discharged from the compressor 63. The heating refrigerant discharged from the compressor 63 flows into the water heat exchanger 65. The heating refrigerant that has flowed into the water heat exchanger 65 exchanges heat with unheated water that has flowed out of the hot water storage tank 71, and is condensed while transferring heat to the unheated water to heat the water. Then, the heating refrigerant flows out of the water heat exchanger 65.

The heating refrigerant that has flowed out of the water heat exchanger 65 is reduced in pressure and expanded by the expansion valve 64, and then flows out of the expansion valve 64. The heating refrigerant that has flowed out of the expansion valve 64 flows into the heating-side intermediate heat exchanger 61. The heating refrigerant that has flowed into the heating-side intermediate heat exchanger 61 exchanges heat with water that flows through the heat medium circuit to receive heat from the water and evaporate, and then flows out of the heating-side intermediate heat exchanger 61. The heating refrigerant that has flowed out of the heating-side intermediate heat exchanger 61 is sucked into the compressor 63. Thereafter, the heating refrigerant repeats the above circulation.

Furthermore, when the water supply pump 72 is driven, unheated water flows out from the outflow port provided in the lower portion of the hot water storage tank 71. The unheated water that has flowed out of the hot water storage tank 71 flows into the water heat exchanger 65. The unheated water that has flowed into the water heat exchanger 65 exchanges heat with the heating refrigerant and is thus heated. Then, the heated water flows out of the water heat exchanger 65. The heated water that has flowed out of the water heat exchanger 65 flows into the hot water storage tank 71 from the inflow port provided in the upper portion of the hot water storage tank 71, and is stored in the hot water storage tank 71. Thereafter, the unheated water in the hot water storage tank 71 repeats the above circulation.

It should be noted that in the system #4, in the case where one of the cooling device 5 and the heating device 6 is in the stopped state, the controller 4 controls the opening degree of one of the cooling-side heat-medium flow adjusting valve 52 and the heating-side heat-medium flow adjusting valve 62 that is associated with the above one of the cooling device 5 and the heating device 6 that is in the stopped state. Under such a control, the cooling-side intermediate heat exchanger 51 or the heating-side intermediate heat exchanger 61 that is associated with the device being in the stopped state is bypassed. Furthermore, in the system #4, in the case where both the cooling device 5 and the heating device 6 of the system #4 are in the stopped state, the controller 4 performs a control of causing at least one of the cooling-side heat-medium flow adjusting valve 52 and the heating-side heat-medium flow adjusting valve 62 to be closed, thereby stopping the supply of water to the system #4.

(Use of Exhaust Heat)

In Embodiment 5, when flowing into the cooling-side intermediate heat exchanger 51 of the cooling device 5, cooled water recovers exhaust heat from the cooling device 5, and is thus heated. Then, the water flows out of the cooling-side intermediate heat exchanger 51. The water that has flowed out of the cooling-side intermediate heat exchanger 51 flows into the heating-side intermediate heat exchanger 61 of the heating device 6, while being in the heated state.

Furthermore, when the water that has flowed out of the cooling-side intermediate heat exchanger 51 flows into the heating-side intermediate heat exchanger 61, the water recovers exhaust heat from the heating device 6, and is thus cooled. Then, the water flows out of the heating-side intermediate heat exchanger 61. The water that has flowed out of the heating-side intermediate heat exchanger 61 flows into the relay unit 3 as return water, while being in the cooled state.

As described above, in the system #4 in which the cooling device 5 and the heating device 6 are connected in series, exhaust heat from the cooling device 5 is used by the heating device 6. Thus, the heat exchange efficiency of the heating device 6 is improved. Furthermore, exhaust heat from the heating device 6 cools return water to the relay unit 3, thus assisting cooling of water in the relay unit 3 and improving the energy efficiency of the entire system for energy saving.

In the case where the cooling device 5 cannot achieve required operating performance only with heat exchange performed by the cooling-side intermediate heat exchanger 51, a cooling-side auxiliary heat exchanger may be provided upstream or downstream of the cooling-side intermediate heat exchanger 51 in the cooling refrigerant circuit such that the cooling-side auxiliary heat exchanger is connected in series to the cooling-side intermediate heat exchanger 51. Because of provision of such a configuration, the amount of heat exchange that is insufficient in the case where the heat exchange is performed at the cooling-side intermediate heat exchanger 51 only is compensated for the amount of heat exchange at the cooling-side auxiliary heat exchanger, and the cooling device 5 can thus achieve the required operating performance.

However, in the case where the cooling-side auxiliary heat exchanger is provided upstream of the cooling-side intermediate heat exchanger 51, and the cooling device 5 can achieve the required operating performance only with the cooling-side intermediate heat exchanger 51, it is preferable that a cooling-side auxiliary bypass pipe that bypasses the cooling-side auxiliary heat exchanger be provided. This is because when heat exchange is not performed using the cooling-side auxiliary heat exchanger, the amount of heat transferred to water during heat exchange performed using the cooling-side intermediate heat exchanger 51 is increased, and use of exhaust heat by the heating device 6, which is located downstream of the cooling device 5, can be improved.

On the other hand, in the case where the cooling-side auxiliary heat exchanger is provided downstream of the cooling-side intermediate heat exchanger 51, it is not necessary to provide the cooling-side auxiliary bypass pipe. That is, in the case where the shortage of the amount of heat exchange performed using the cooling-side intermediate heat exchanger 51 is compensated for the amount of heat exchange using the cooling-side auxiliary heat exchanger, the cooling-side auxiliary heat exchanger may be used.

Furthermore, in the case where the heating device 6 cannot achieve the required operating performance only with heat exchange performed using the heating-side intermediate heat exchanger 61, a heating-side auxiliary heat exchanger may be provided upstream or downstream of the heating-side intermediate heat exchanger 61 such that the heating-side auxiliary heat exchanger is connected in series to the heating-side intermediate heat exchanger 61. Because of provision of such a configuration, the amount of heat exchange that is insufficient in the case where the heat exchange is performed using the heating-side intermediate heat exchanger 61 only is compensated for the amount of heat exchange using the heating-side auxiliary heat exchanger, and the heating device 6 can thus achieve the required operating performance.

However, in the case where the heating-side auxiliary heat exchanger is provided upstream of the heating-side intermediate heat exchanger 61, and the heating device 6 can achieve the required operating performance using the heating-side intermediate heat exchanger 61 only, it is preferable that a heating-side auxiliary bypass pipe that bypasses the heating-side auxiliary heat exchanger be provided. This is because in the case where heat exchange is not performed using the heating-side auxiliary heat exchanger, the amount of heat transferred to water during heat exchange performed using the heating-side intermediate heat exchanger 61 is increased, and use of exhaust heat in return water can be improved.

On the other hand, in the case where heating-side auxiliary heat exchanger is provided downstream of the heating-side intermediate heat exchanger 61, it is not necessary to provide the heating-side auxiliary bypass pipe. That is, in the case where the shortage of the amount of heat exchange performed using the heating-side intermediate heat exchanger 61 is compensated for the amount of heat exchange performed using the heating-side auxiliary heat exchanger, the heating-side auxiliary heat exchanger may be used.

(Case where Heat Recovery and Another Heat Recovery are Balanced)

The balance between heat recovery by the cooling-side intermediate heat exchanger 51 and that by the heating-side intermediate heat exchanger 61 will be described. In the case where a water circulation passage in which only the system #4 is connected to the relay unit 3 is provided by, for example, a control of inhibiting water from flowing into the system #1, when heat recovered by the cooling-side intermediate heat exchanger 51 and heat recovered by the heating-side intermediate heat exchanger 61 are balanced, the operation of the outdoor unit 1 may be stopped. That is, heat exchange between the cooling device 5 and the heating device 6 can be carried out simply by an operation of driving the pump 33 of the heat medium circuit to cause water to circulate in the system #4, and an energy saving operation can thus be performed. It should be noted that the case where “heat recovery and another heat recovery are balanced” is not limited to the case where the inlet temperature and the outlet temperature of water are equal to each other in a system where the cooling device 5 and the heating device 6 are connected in series. For example, the above case also covers the case where heat recovery and another heat recovery are substantially balanced as in the case where the difference between the temperature of water that flows into the system #4 and the temperature of water that flows out of the system #4 is not great, and the influence of a change in temperature is thus small in the entire heat medium circuit. Furthermore, the above case also covers the case where the heat recovery and another heat recovery are balanced even in the case where the temperature of water changes at any portion of the heat medium circuit, for example, in the case where the temperature of water changes because of heat exchange between outside air and water during circulation of the water through the heat medium pipe 20.

(Case where Heat Recovery and Another Heat Recovery are not Balanced)

For example, when the indoor units 2 of the system #1 perform the heating operation, and the amount of heat transferred to water at the cooling-side intermediate heat exchanger 51 is larger than the amount of heat received from water at the heating-side intermediate heat exchanger 61, water that flows out of the system #4 has a high temperature. That is, when the temperature of water that flows out of the system #4 is higher than the temperature of water that flows into the system #4, return water to the relay unit 3 has a high temperature. Therefore, the operating frequency of the compressor 11 or the rotation speed of a fan that sends air to the heat-source-side heat exchanger 13 may be reduced to reduce the load on the outdoor unit 1.

On the other hand, when the indoor units 2 of the system #1 perform the cooling operation, and the temperature of water that flows out of the system #4 is higher than the temperature of water that flows into the system #4, return water to the relay unit 3 has a high temperature. It is therefore necessary to increase the load on the outdoor unit 1. As described above, in order to maintain the operating state of the system #1, it is necessary to control the load on the outdoor unit 1 based on the operating state of the indoor units 2 of the system #1 and the temperatures of water that flows into and flows out of the system #4.

In view of the above, in Embodiment 5, when heat recovery by the cooling-side intermediate heat exchanger 51 and that by the heating-side intermediate heat exchanger 61 are not balanced, the load on the outdoor unit 1 is adjusted based on the operating states of the indoor units 2 of the system #1 and the temperatures of water that flows into and flows out of the system #4.

FIG. 23 is a flowchart illustrating an example of the flow of processing in the case where heat recovery by the cooling-side intermediate heat exchanger 51 and that by the heating-side intermediate heat exchanger 61 in Embodiment 5 are not balanced. First, in step S1, the controller 4 determines whether or not the indoor units 2 of the system #1 are in the heating operation.

In the case where the indoor units 2 are in the heating operation (Yes in step S1), in step S2, the controller 4 compares the inlet temperature of water in the system #4 that is detected by the inlet temperature sensor 56 and the outlet temperature of water in the system #4 that is detected by the outlet temperature sensor 67 with each other. As the result of the comparison, when the inlet temperature in the system #4 is higher than the outlet temperature in the system #4 (Yes in step S2), in step S3, the controller 4 controls components in the outdoor unit 1, such as the compressor 11, and components in the relay unit 3, to increase the load on the outdoor unit 1 in order to increase the amount of heat exchange at the intermediate heat exchanger 32. By contrast, when the inlet temperature in the system #4 is lower than or equal to the outlet temperature in the system #4 (No in step S2), the state of return water that flows out of the system #4 is a state in which heat is accumulated in the return water. Therefore, in step S4, the controller 4 controls the components of the outdoor unit 1 and the relay unit 3 to reduce the load on the outdoor unit 1 in order to reduce the amount of heat exchange at the intermediate heat exchanger 32.

Furthermore, in step S1, when the indoor units 2 are in cooling operation (No in step S1, in step S5, the controller 4 compares the inlet temperature of water in the system #4 and the outlet temperature of water in the system #4 with each other. As the result of the comparison, when the inlet temperature in the system #4 is lower than or equal to the outlet temperature in the system #4 (No in step S5), the controller 4 controls in step S6, the components in the outdoor unit 1 and in the relay unit 3 to increase the load on the outdoor unit 1 in order to increase the amount of heat exchange in the intermediate heat exchanger 32. By contrast, when the inlet temperature in the system #4 is higher than the outlet temperature in the system #4 (Yes in step S5), the state of return water that flows out of the system #4 is a state where heat is accumulated in the return water. Therefore, in step S7, the controller 4 controls the components in the outdoor unit 1 and in the relay unit 3 to reduce the load on the outdoor unit 1 in order to reduce the amount of heat exchange in the intermediate heat exchanger 32.

Next, in step S3 or step S6, in the case where the load on the outdoor unit 1 is increased, in step S8, the controller 4 makes a comparison between the amount of increase in electric power in the outdoor unit 1 that is caused by increase in the load and the amount of decrease in electric power in the heat medium circuit, i.e., in the cooling device 5 and the heating device 6 that is caused by use of exhaust heat in the system #4. As the result of the comparison, when the amount of increase in electric power in the outdoor unit 1 is larger than the amount of decrease in electric power in the heat medium circuit (Yes in step S8), in step S9, the controller 4 returns the load on the outdoor unit 1 that is increased in step S3 or step S6 to an original load. Then, in step S10, the controller 4 controls the opening degree of the cooling-side heat-medium flow adjusting valve 52 or the heating-side heat-medium flow adjusting valve 62 to cause the cooling-side intermediate heat exchanger 51 or the heating-side intermediate heat exchanger 61 in the system #4 to be bypassed.

To be more specific, when the load on the outdoor unit 1 is increased (step S3) because the indoor units 2 are in heating operation and the inlet temperature of water in the system #4 is higher than the outlet temperature of water in the system #4, the controller 4 controls the opening degree of the heating-side heat-medium flow adjusting valve 62 to cause the heating-side intermediate heat exchanger 61 to be bypassed. As described above, when the outlet temperature is low during heating operation, the heating-side intermediate heat exchanger 61 is bypassed to reduce heat to be received, while maintaining heat to be transferred. Furthermore, when the load on the outdoor unit 1 is increased (S6) because the indoor units 2 are in cooling operation and the inlet temperature of water in the system #4 is lower than or equal to the outlet temperature of water in the system #4, the controller 4 controls the opening degree of the cooling-side heat-medium flow adjusting valve 52 to cause the cooling-side intermediate heat exchanger 51 to be bypassed.

On the other hand, when the amount of increase in electric power in the outdoor unit 1 is lower than or equal to the amount of decrease in electric power in the heat medium circuit (No in step S8), in step S11, the controller 4 maintains the load on the outdoor unit 1 increased in step S3 or step S6.

As described above, in Embodiment 5, the load on the outdoor unit 1 is adjusted based on the operating states of the indoor units 2, the temperature of water that flows into the system #4, and the temperature of water that flows out of the system #4. It is therefore possible to cause the cooling device 5 and the heating device 6 to sufficiently achieve operating performance, and also possible to reduce electric power required for the operation of the entire air-conditioning apparatus 500. In this case, steps S8 to S11 are not indispensable. As indicated in FIG. 23, the load on the outdoor unit is controlled only based on the comparison between the inlet temperature and the outlet temperature in the system #4, but may be controlled also in consideration of the difference between temperatures of water in another system or a change in temperature of water in the pipe.

Regarding this example, although it is described above that when the amount of increase in electric power in the outdoor unit 1 is larger than the amount of decrease in electric power in the heat medium circuit, the cooling-side intermediate heat exchanger 51 or the heating-side intermediate heat exchanger 61 is bypassed in step S10. This, however, is not limiting. For example, the cooling-side intermediate heat exchanger 51 or the heating-side intermediate heat exchanger 61 may not be bypassed.

In the case where the cooling-side intermediate heat exchanger 51 or the heating-side intermediate heat exchanger 61 is bypassed, an increase in electric power in the entire air-conditioning apparatus 500 is reduced. This is thus effective from an electrical point of view. By contrast, in the case where the cooling-side intermediate heat exchanger 51 or the heating-side intermediate heat exchanger 61 is not bypassed, exhaust heat in the cooling device 5 can be used by the heating device 6. This is thus effective from a thermal point of view. Therefore, whether the cooling-side intermediate heat exchanger 51 or the heating-side intermediate heat exchanger 61 is bypassed or not may be determined as appropriate in consideration of a desired advantage to be obtained when the cooling-side intermediate heat exchanger 51 or the heating-side intermediate heat exchanger 61 is bypassed or not bypassed. Furthermore, water may be partially caused to bypass the cooling-side intermediate heat exchanger 51 or the heating-side intermediate heat exchanger 61. That is, in order to reduce the difference between the inlet temperature of water in the system #4 and the outlet temperature of water in the system #4, the distribution of water to the intermediate heat exchanger and the bypass passage may be controlled by the cooling-side heat-medium flow adjusting valve 52 or the heating-side heat-medium flow adjusting valve 62. In this case, it is possible to recover exhaust heat while reducing an increase in electric power in the outdoor unit 1.

In the case where the cooling-side intermediate heat exchanger 51 is bypassed, the cooling refrigerant in the cooling device 5 is not sufficiently condensed, and thus, as described above, it is necessary to provide and connect the cooling-side auxiliary heat exchanger in series to the cooling-side intermediate heat exchanger 51. Furthermore, in the case where the heating-side intermediate heat exchanger 61 is bypassed, the heating refrigerant in the heating device 6 is not sufficiently evaporated, and thus, as described above, it is necessary to provide and connect the heating-side auxiliary heat exchanger in series to the heating-side intermediate heat exchanger 61.

Moreover, in this example, whether the changed load on the outdoor unit 1 is returned or not is determined based on the comparison between the amount of increase in electric power in the outdoor unit 1 and the amount of decrease in electric power in the heat medium circuit. In addition to this, the amount of change in electric power in the cooling device 5 and the heating device 6 may be considered.

Although it is not referred to in the above description, in the air-conditioning apparatus 500, as in Embodiments 1 to 4, a flow-rate control process is performed to cause water to flow at a required flow rate, through the FCUs 21a to 21c, the cooling device 5, and the heating device 6. That is, in the air-conditioning apparatus 500, the opening degrees of the heat-medium flow adjusting valves 22, the cooling-side heat-medium flow adjusting valve 52 and the heating-side heat-medium flow adjusting valve 62 that are associated with the FCUs 21a to 21c, respectively, are controlled. Thus, the flow rates of water for the FCU 21a to 21c, the cooling-side intermediate heat exchanger 51 and the heating-side intermediate heat exchanger 61 are adjusted based on required performance for the FCUs 21a to 21c, the cooling-side intermediate heat exchanger 51 and the heating-side intermediate heat exchanger 61.

In Embodiment 5, the cooling device 5 and the heating device 6 in the system #4 may be interchanged with each other. To be more specific, the heating device 6 may be provided on the upstream side in the flow of water in the system #4, and the cooling device 5 may be provided on the downstream side in the flow of water in the system #4. Furthermore, the numbers of cooling devices 5 and heating devices 6 connected in series in the system #4 are not limited to the numbers described above regarding this embodiment, and a plurality of cooling devices 5 and a plurality of heating devices 6 may be connected in series.

Furthermore, the cooling-side bypass pipe 50 of the cooling device 5 and the heating-side bypass pipe 60 of the heating device 6 can be omitted. In this case, when water is caused to flow through the cooling-side intermediate heat exchanger 51, with the cooling device 5 being in the stopped state, water flows through the cooling-side intermediate heat exchanger 51 without exchanging heat. Thus, it is possible to obtain an advantage equivalent to that in the case where the cooling-side intermediate heat exchanger 51 is bypassed. Also, when water is caused to flow through the heating-side intermediate heat exchanger 61, with the heating device 6 being in the stopped state, water flows through the heating-side intermediate heat exchanger 61 without exchanging heat. Thus, it is possible to obtain an advantageous effect substantially equal to an advantage equivalent to that in the case where the heating-side intermediate heat exchanger 61 is bypassed.

However, when water passes through the cooling-side intermediate heat exchanger 51 or the heating-side intermediate heat exchanger 61, some loss and pressure loss due to transfer of heat occur at the cooling-side intermediate heat exchanger 51 and the heating-side intermediate heat exchanger 61. Therefore, it is preferable that the cooling-side bypass pipe 50 and the heating-side bypass pipe 60 be provided.

In the cooling device 5 from which the cooling-side bypass pipe 50 is omitted, the cooling-side heat-medium flow adjusting valve 52 does not need to have a plurality of outflow ports, and has only to have a function of adjusting the flow rate of water that flows into the cooling-side heat-medium flow adjusting valve 52 and allowing the water to flow out at the adjusted flow rate. Similarly, in the heating device 6 from which the heating-side bypass pipe 60 is omitted, the heating-side heat-medium flow adjusting valve 62 does not need to have a plurality of outflow ports, and has only to have a function of adjusting the flow rate of water that flows into the heating-side heat-medium flow adjusting valve 62 and allowing the water to flow out at the adjusted flow rate.

In this example, the system #4 includes the cooling device 5 and the heating device 6 that are connected in series, and the system #4 is connected parallel to the system #1. This, however, is not limiting. For example, the system #4 may include the cooling device 5 only. In this case, the load on the outdoor unit 1 and the flow of water in the system #4 are controlled based on the operating state of the system #1.

In the case where the indoor units 2 of the system #1 are in heating operation, the temperature of water that flows out of the cooling device 5 of the system #4 is higher than the temperature of water that flows into the cooling device 5 and return water to the relay unit 3 thus has a high temperature. Therefore, the load on the outdoor unit 1 may be reduced. Thus, the controller 4 performs a control of causing the load on the outdoor unit 1 to be reduced. Therefore, the electric power required for the entire air-conditioning apparatus 500 can be reduced.

By contrast, in the case where the indoor units 2 of the system #1 are in cooling operation, the temperature of water that flows out of the cooling device 5 of the system #4 is higher than the temperature of water that flows into the cooling device 5 and return water to the relay unit 3 thus has a high temperature. Therefore, it is necessary to increase the load on the outdoor unit 1. However, when the control of increasing the load is performed, the electric power required for the entire air-conditioning apparatus 500 is increased. In view of the above, in this case, water that flows into the cooling device 5 is blocked. Thus, the load on the pump 33 is reduced and the energy efficiency can thus be improved for energy saving.

In such a case, in the cooling device 5, cooling refrigerant cannot be condensed by the cooling-side intermediate heat exchanger 51. Therefore, as described above, the cooling-side auxiliary heat exchanger is connected in series to the cooling-side intermediate heat exchanger 51, and cooling refrigerant is condensed by the cooling-side auxiliary heat exchanger.

A control depending on whether the above cooling-side auxiliary heat exchanger is provided or not may be performed. That is, as indicated in FIG. 23, when the indoor units 2 are in heating operation (Yes in step S1), the controller 4 compares the temperature of water that is detected by the inlet temperature sensor 56 of the cooling device 5 and the temperature of refrigerant that is detected by a discharge temperature sensor provided in the compressor. In the case where the cooling device 5 includes a cooling-side auxiliary condenser, when the temperature of water is higher than the temperature of refrigerant, the controller 4 may perform a control of causing water to flow through the cooling-side bypass pipe 50 to allow the cooling device 5 to be operated substantially by the cooling-side auxiliary condenser only. By contrast, in the case where the cooling device 5 does not include the cooling-side auxiliary condenser, the cooling device 5 cannot condense refrigerant. Therefore, when the temperature of water is higher than the temperature of refrigerant, the controller 4 may cause the outdoor unit 1 to be in the stopped state. Because of provision of such a configuration, it is possible to prevent occurrence of a problem in which heat cannot be transferred from the refrigerant to water in the cooling-side intermediate heat exchanger 51 when the temperature of the water is higher than the temperature of refrigerant during heating operation.

Furthermore, in Embodiment 5, the system #4 may include the heating device 6 only, and may be connected parallel to the system #1. Also in this case, the load on the outdoor unit 1 and the flow of water in the system #4 are controlled based on the operating state of the system #1.

In the case where the indoor units 2 of the system #1 are in heating operation, the temperature of water that flows out of the heating device 6 of the system #4 is lower than the temperature of water that flows into the heating device 6, and return water to the relay unit 3 thus has a low temperature. Therefore, it is necessary to increase the load on the outdoor unit 1. However, when the control of increasing the load is performed, the electric power required for the entire air-conditioning apparatus 500 is increased. In view of the above, in this case, water that flows into the heating device 6 is blocked. Thus, the load on the pump 33 is reduced and the energy efficiency can be improved for energy saving.

By contrast, in the case where the indoor units 2 of the system #1 are in cooling operation, the temperature of water that flows out of the heating device 6 of the system #4 is lower than the temperature of water that flows into the heating device 6 and return water to the relay unit 3 thus has a low temperature. Therefore, the load on the outdoor unit 1 may be reduced. Accordingly, the controller 4 performs a control of reducing the load on the outdoor unit 1. Thus, the electric power required for the entire air-conditioning apparatus 500 can be reduced.

In such a case, in the heating device 6, heating refrigerant cannot be evaporated by the heating-side intermediate heat exchanger 61. Therefore, as described above, the heating-side auxiliary heat exchanger is connected in series to the heating-side intermediate heat exchanger 61 of the heating device 6, and heating refrigerant is evaporated by the heating-side auxiliary heat exchanger.

In this case, the control depending on whether the heating-side auxiliary heat exchanger is provided or not may be performed during the above cooling operation. That is, in the case where the indoor units 2 are in cooling operation (No in step S1), the controller 4 compares the temperature of water that is detected by the inlet temperature sensor 66 of the heating device 6 and the temperature of refrigerant that is detected by the suction temperature sensor provided in the compressor. In the case where the heating device 6 includes a heating-side auxiliary condenser, when the temperature of water is lower than the temperature of refrigerant, the controller 4 may perform a control of causing water to flow through the heating-side bypass pipe 60 to cause the heating device 6 to be operated substantially by the heating-side auxiliary condenser only. By contrast, in the case where the heating device 6 does not include the heating-side auxiliary condenser, the heating device 6 cannot evaporate refrigerant. Therefore, when the temperature of water is lower than the temperature of refrigerant, the controller 4 may cause the outdoor unit 1 to be in the stopped state. Therefore, it is possible to prevent occurrence of a problem in which heat cannot be transferred from the refrigerant to the water in the cooling-side intermediate heat exchanger 51 when the temperature of water is lower than the temperature of refrigerant during cooling operation.

Furthermore, in Embodiment 5, the cooling device 5 and the heating device 6 may be included in respective systems, and the systems may be connected parallel to the system #1. Also in this case, the load on the outdoor unit 1 and the flow of water in each system are controlled based on the operating state of the system #1.

In the case where the indoor units 2 of the system #1 are in heating operation, the temperature of water that flows out of the system of the cooling device 5 is higher than the temperature of water that flows into the system of the cooling device 5 and return water to the relay unit 3 thus has a high temperature. Furthermore, the temperature of water that flows out of the system of the heating device 6 is lower than the temperature of water that flows into the system of the heating device 6, and return water to the relay unit 3 thus has a low temperature. Therefore, the controller 4 performs a control of reducing the load on the outdoor unit 1, and shutting out the flow of the water into the system of the heating device 6 or causing the water to bypass the heating-side intermediate heat exchanger 61.

By contrast, in the case where the indoor units 2 of the system #1 are in cooling operation, the temperature of water that flows out of the system of the cooling device 5 is higher than the temperature of water that flows into the system of the cooling device 5, and return water to the relay unit 3 thus has a high temperature. Furthermore, the temperature of water that flows out of the system of the heating device 6 is lower than the temperature of water that flows into the system of the heating device 6, and return water to the relay unit 3 thus has a low temperature. Therefore, the controller 4 performs a control of reducing the load on the outdoor unit 1, and blocking the flow of the water into the system of the cooling device 5 or causing the water to bypass the cooling-side intermediate heat exchanger 51.

In such a manner, the load on the outdoor unit 1 and the flow of water in each system are controlled based on the operating states of the indoor units 2 of the system #1, whereby the electric power required for the entire air-conditioning apparatus 500 can be reduced, the load on the pump 33 can be reduced, and the energy efficiency can be improved for energy saving. Also in this case, in the cooling device 5, the cooling refrigerant is condensed by the cooling-side auxiliary heat exchanger, and in the heating device 6, the heating refrigerant is evaporated by the heating-side auxiliary heat exchanger.

As described above, in the air-conditioning apparatus 500 according to Embodiment 5, the cooling device 5 and the heating device 6 are connected in series. Because of such a configuration, exhaust heat from the cooling device 5 is used by the heating device 6, and the heat exchange efficiency of the heating device 6 can thus be improved. Furthermore, since return water is cooled by exhaust heat from the heating device 6, and the energy efficiency of the entire system can be improved for energy saving.

The cooling device 5 further includes the cooling-side bypass pipe 50 that bypasses the cooling-side intermediate heat exchanger 51. Thus, when the cooling-side intermediate heat exchanger 51 does not cause heat exchange between water and the cooling refrigerant, water passes through the cooling-side bypass pipe 50. Therefore, the pressure loss and the loss due to transfer of heat can be reduced, compared with the case where water passes through the cooling-side intermediate heat exchanger 51.

Furthermore, the cooling-side bypass pipe 50 is provided to extend through a region located outside of the cooling device 5. Thus, since the length of the cooling-side bypass pipe 50 is shortened, it is possible to reduce the loss caused by transfer of heat, etc., when water flows through the pipe.

Also, the heating device 6 includes the heating-side bypass pipe 60 that bypasses the heating-side intermediate heat exchanger 61. Thus, when the heating-side intermediate heat exchanger 61 does not cause heat exchange to be performed between water and the heating refrigerant, water passes through the heating-side bypass pipe 60. Therefore, it is possible to reduce the pressure loss and the loss caused by transfer of heat, compared with the case where water passes through the heating-side intermediate heat exchanger 61.

Furthermore, the heating-side bypass pipe 60 is provided to extend through a region located outside the heating device 6. Thus, since the length of the heating-side bypass pipe 60 is shortened, it is possible to reduce the loss caused by transfer of heat when water flows through the pipe.

The cooling device 5 further includes a cooling-side auxiliary heat exchanger connected in series to the cooling-side intermediate heat exchanger 51 at a location upstream or downstream of the cooling-side intermediate heat exchanger 51 in the cooling refrigerant circuit. With such a configuration, the amount of heat exchange that is insufficient when the heat exchange is performed by the cooling-side intermediate heat exchanger 51 only is compensated for, and the cooling refrigerant can thus be sufficiently condensed.

The cooling device 5 further includes a cooling-side auxiliary bypass pipe that bypasses the cooling-side auxiliary heat exchanger that is provided upstream of the cooling-side intermediate heat exchanger 51. Thus, when the cooling device 5 can achieve required operating performance using the cooling-side intermediate heat exchanger 51 only, the cooling-side auxiliary heat exchanger can be bypassed.

The heating device 6 further includes a heating-side auxiliary heat exchanger connected in series to the heating-side intermediate heat exchanger 61 at a location upstream or downstream of the heating-side intermediate heat exchanger 61 in the heating refrigerant circuit. Thus, the amount of heat exchange that is insufficient when the heat exchange is performed at the heating-side intermediate heat exchanger 61 only is compensated for, and the heating refrigerant can thus be sufficiently evaporated.

The heating device 6 further includes a heating-side auxiliary bypass pipe that bypasses the heating-side auxiliary heat exchanger that is provided upstream of the heating-side intermediate heat exchanger 61. Thus, in the case where the heating device 6 can achieve required operating performance using the heating-side intermediate heat exchanger 61 only, the heating-side auxiliary heat exchanger can be bypassed.

The air-conditioning apparatus 500 further includes the controller 4 that adjusts the load on the outdoor unit 1 based on the operating states of the indoor units 2 of the system #1 and the temperatures of water that flows into and flows out of the system #4 in which the cooling device 5 and the heating device 6 are connected. When the indoor units 2 are in heating operation, and the inlet temperature of water that flows into the system #4 is higher than the outlet temperature of water that flows out of the system #4, or when the indoor units 2 are in cooling operation, and the outlet temperature in the system #4 is higher than or equal to the inlet temperature in the system #4, the controller 4 increases the load on the outdoor unit 1. Furthermore, when the indoor units 2 are in heating operation, and the outlet temperature in the system #4 is higher than or equal to the inlet temperature in the system #4, or when the indoor units 2 are in cooling operation, and the inlet temperature in the system #4 is higher than the outlet temperature in the system #4, the controller 4 reduces the load on the outdoor unit 1. Because of provision of such a configuration, it is possible to cause the cooling device 5 and the heating device 6 to sufficiently achieve operating performance, and also possible to reduce the electric power required for the operation of the entire air-conditioning apparatus 500.

Embodiment 6

Next, an air-conditioning apparatus according to Embodiment 6 of the present disclosure will be described. In Embodiment 6, the opening degree of the heat-medium flow adjusting valves 22 are controlled to reduce the degree of deficiency in the starting performance of the indoor units 2a to 2i at the time when the indoor units 2a to 2i start their operation from the stopped state. Regarding Embodiment 6, components that are the same as Embodiment 1 will be denoted by the same reference signs, and their detailed descriptions will thus be omitted.

In Embodiment 6, the valve opening-degree determination unit 42 set the opening degrees of the heat-medium flow adjusting valves 22 in the indoor units 2a to 2i such that when all the indoor units 2a to 2i are in the stopped state, the heat-medium flow adjusting valves 22 allow water that circulates in the heat medium circuit to flow through the indoor-side bypass pipes 23. To be more specific, the valve opening-degree determination unit 42 sets the opening degrees of all the heat-medium flow adjusting valves 22 such that the bypass opening degrees are 100%, thereby causing the second outflow ports 22c to communicate with the water outflow sides of the FCUs 21.

In such a manner, by controlling the opening degrees of the heat-medium flow adjusting valves 22 such that water that circulates in the heat medium circuit flows through the indoor-side bypass pipes 23, heat is accumulated in water that is a heat medium. Thus, it is possible to perform precooling or preheating such that the temperature of water that circulates in the heat medium circuit reaches a temperature suitable for air conditioning, and it is therefore possible to reduce the degree of deficiency in the starting performance of the indoor units 2a to 2i at the time when the indoor units 2a to 2i start their operations from the stopped state.

As described above, in the air-conditioning apparatus 100 according to Embodiment 6, the valve opening-degree determination unit 42 sets the opening degrees of all the heat-medium flow adjusting valves 22 such that when the indoor units 2a to 2i are in the stopped state, the heat-medium flow adjusting valves 22 allow the second outflow ports 22c and the water outflow sides of the FCUs 21 to communicate with each other. Thus, heat is accumulated in water serving as the heat medium, and it is therefore possible to reduce the degree of deficiency in the starting performance of the indoor units 2a to 2i at the time when the indoor units 2a to 2i start their operation from the stopped state.

Although the above descriptions are made with respect to Embodiments 1 to 6 of the present disclosure, they are not limiting, and various modifications and applications can be made without departing from the scope of the present disclosure. For example, it is explained above that the outdoor unit 1 and the relay unit 3 are formed as separate units, but such an explanation is not limiting. The outdoor unit 1 and the relay unit 3 may be formed as a single body. Furthermore, Embodiments 1 to 6 can be combined as appropriate.

Furthermore, it is explained above that the opening degree of the heat-medium flow adjusting valve 22 is determined based on FCU performance, which can be found from various temperature information. However, this is also true of other examples. For example, the opening degree of the heat-medium flow adjusting valve 22 may be determined based on information on whether each of the indoor units 2 is in the thermos-on state or the thermos-off state.

Moreover, a radiant panel may be used as a load-side unit. At the radiant panel, when a heat medium flows through a pipe of the radiant panel, heat exchange is performed. Therefore, in the thermo-off state, the heat medium is caused to flow through a bypass pipe to inhibit the heat medium from flowing through the pipe of the radiant panel.

Furthermore, although it is described above that the pump 33 is provided in the relay unit 3, the description is not limiting. The pump 33 may be formed separate from the relay unit 3 as a pump unit, for example.

REFERENCE SIGNS LIST

- 1 outdoor unit 2, 2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h, 2i indoor unit 3 relay unit 4 controller 5 cooling device 6 heating device 10 refrigerant pipe
- 11 compressor 12 refrigerant-flow switching device 13 heat-source-side heat exchanger 14 accumulator 20 heat medium pipe 21, 21a, 21b, 21c, 21d, 21e, 21f, 21g, 21h, 21i fan coil unit 22 heat-medium flow adjusting valve 22a inflow port 22b first outflow port 22c second outflow port
- 22
  d body 22e opening-degree adjusting valve 22f side wall 22g partition wall 22h opening port 23 indoor-side bypass pipe 24 inlet temperature sensor 25 outlet temperature sensor 26 suction temperature sensor 27 indoor-side controller 31 expansion valve 32 intermediate heat exchanger 33 pump 41 FCU performance calculation unit 42 valve opening-degree determination unit 43 valve control unit 44 heat-medium flow-rate determination unit 45 pump control unit 46 storage unit 50 cooling-side bypass pipe 51 cooling-side intermediate heat exchanger 52 cooling-side heat-medium flow adjusting valve 52a inflow port 52b first outflow port 52c second outflow port 53 compressor 54 expansion valve 55 use-side heat exchanger 56 inlet temperature sensor
- 57 outlet temperature sensor 58 suction temperature sensor 60 heating-side bypass pipe 61 heating-side intermediate heat exchanger 62 heating-side heat-medium flow adjusting valve 62a inflow port 62b first outflow port 62c second outflow port 63 compressor 64 expansion valve 65 water heat exchanger 66 inlet temperature sensor 67 outlet temperature sensor 68 heat medium temperature sensor 71 hot water storage tank 72 water supply pump 100, 200, 300, 400, 500 air-conditioning apparatus 121 use-side heat exchanger 122 fan

AIR-CONDITIONING APPARATUS

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