JP7826808B2 - air conditioner - Google Patents

Description

The technology disclosed herein relates to air conditioners.

Air conditioners are known that perform an internal cleaning operation after cooling operation, in which the indoor heat exchanger is heated while maintaining condensation on its surface (Patent Document 1). Such air conditioners can sterilize the indoor heat exchanger by heating it, and can dry it so that mold growth is suppressed.

Japanese Patent Application Laid-Open No. 2020-115063

Air conditioners are known that include a primary circuit through which a refrigerant circulates and exchanges heat with outdoor air, a secondary circuit through which water circulates and exchanges heat with indoor air, and a heat exchanger that exchanges heat between the refrigerant and water (or other refrigerant). When performing interior cleaning operation after cooling operation, such air conditioners need to heat water to the temperature required to disinfect and dry the indoor heat exchanger, which presents a problem: it takes time to heat the water.

The disclosed technology was developed in light of these issues, and aims to provide an air conditioner that can quickly change the temperature of the refrigerant that exchanges heat with a different working fluid.

An air conditioner according to one aspect of the present disclosure includes a first circuit through which a first refrigerant circulates, a second circuit through which a second refrigerant different from the first refrigerant circulates, a heat exchanger that exchanges heat between the first refrigerant and the second refrigerant, an indoor heat exchanger that exchanges heat between the second refrigerant and indoor air, a heat storage tank in which a portion of the second refrigerant is stored, a valve that connects the heat storage tank to the second circuit and disconnects the heat storage tank from the second circuit, and a control unit that controls the valve.

The disclosed air conditioner can change the temperature of the refrigerant that exchanges heat with a different working fluid in a short period of time.

FIG. 1 is a circuit diagram showing an air conditioner according to a first embodiment. FIG. 2 is a block diagram showing the air conditioner of the first embodiment. FIG. 3 is a circuit diagram showing an air conditioner according to a second embodiment.

An air conditioner according to an embodiment disclosed in this application will be described in detail below with reference to the drawings. Note that the following description does not limit the technology of this disclosure. Furthermore, in the following description, identical components will be assigned the same reference numerals, and duplicate explanations will be omitted.

Figure 1 is a circuit diagram showing an air conditioner 1 of Example 1. The air conditioner 1 includes an outdoor unit 2 and an indoor unit 3. The outdoor unit 2 is installed outdoors. The indoor unit 3 is installed in a room that is cooled or heated by the air conditioner 1. The air conditioner 1 further includes a refrigerant circuit 5 (first circuit) through which a refrigerant (e.g., R32 or R290) serving as a first refrigerant circulates, and a water circuit 6 (second circuit) through which water (e.g., antifreeze) serving as a second refrigerant circulates. The refrigerant circuit 5 is located inside the outdoor unit 2. The refrigerant circuit 5 includes a compressor 11, a four-way valve 12, an outdoor heat exchanger 14, an expansion valve 15, and an intermediate heat exchanger 16.

The compressor 11 is equipped with a suction pipe 17 and a discharge pipe 18. The compressor 11 compresses the low-temperature, low-pressure gas-phase refrigerant supplied via the suction pipe 17 in accordance with its rotational speed, and discharges the high-temperature, high-pressure gas-phase refrigerant produced by the compression of the low-temperature, low-pressure gas-phase refrigerant into the discharge pipe 18.

The four-way valve 12 has a first connection port 121, a second connection port 122, a third connection port 123, and a fourth connection port 124. The first connection port 121 is connected to the suction pipe 17 and is connected to the compressor 11 via the suction pipe 17. The second connection port 122 is connected to the discharge pipe 18 and is connected to the compressor 11 via the discharge pipe 18. The third connection port 123 is connected to the outdoor heat exchanger 14. The fourth connection port 124 is connected to the intermediate heat exchanger 16. The four-way valve 12 can be switched to a heating position or a cooling position. When the four-way valve 12 is switched to the heating position, the second connection port 122 is connected to the fourth connection port 124, and the third connection port 123 is connected to the first connection port 121. When the four-way valve 12 is switched to the cooling position, the second connection port 122 is connected to the third connection port 123, and the fourth connection port 124 is connected to the first connection port 121.

One of the outdoor heat exchanger 14's inlet and outlet ports is connected to the third connection port 123, and the other is connected to the expansion valve 15. One of the intermediate heat exchanger 16's inlet and outlet ports is connected to the fourth connection port 124, and the other is connected to the expansion valve 15.

The water circuit 6 includes a pump 21 and an indoor heat exchanger 22. The pump 21 is located inside the outdoor unit 2. The suction side of the pump 21 is connected to the intermediate heat exchanger 16, and the discharge side is connected to the indoor heat exchanger 22. The pump 21 circulates water through the water circuit 6 by discharging water supplied from the intermediate heat exchanger 16 to the indoor heat exchanger 22. Note that a heat medium other than water may also be used in the water circuit 6. An example of a heat medium is antifreeze. The indoor heat exchanger 22 is located inside the indoor unit 3. The indoor heat exchanger 22 is connected to the intermediate heat exchanger 16 via a water circuit on-off valve 42, which will be described later.

The water circuit 6 further includes an indoor heat exchanger circulating water temperature sensor 23 (second temperature sensor) and an intermediate heat exchanger circulating water temperature sensor 24 (second temperature sensor). The indoor heat exchanger circulating water temperature sensor 23 is provided near the indoor heat exchanger 22 in the piping connecting the pump 21 and the indoor heat exchanger 22, and measures the temperature of the water flowing from the pump 21 to the indoor heat exchanger 22. The intermediate heat exchanger circulating water temperature sensor 24 is provided near the intermediate heat exchanger 16 in the piping connecting the indoor heat exchanger 22 and the intermediate heat exchanger 16, and measures the temperature of the water flowing from the indoor heat exchanger 22 to the intermediate heat exchanger 16.

The air conditioner 1 further includes a heat storage tank circuit 31. The heat storage tank circuit 31 is disposed inside the outdoor unit 2. A heat storage flow path 32 is formed in the heat storage tank circuit 31. One end of the heat storage flow path 32 is connected to an upstream branch point 34 formed in a flow path 33 of the water circuit 6 between the pump 21 and the indoor heat exchanger 22. The other end of the heat storage flow path 32 is connected to a downstream branch point 35 formed in the flow path 33 between the upstream branch point 34 and the intermediate heat exchanger 16.

The thermal storage tank circuit 31 includes a hot water thermal storage tank 41 (thermal storage tank), a water circuit on-off valve 42 (valve), an upstream on-off valve 43 (valve), and a downstream on-off valve 44 (valve). The hot water thermal storage tank 41 is provided midway along the thermal storage flow path 32 and stores the water flowing through the thermal storage flow path 32. The water circuit on-off valve 42 is provided midway along a flow path 45 that connects the upstream branch point 34 and the downstream branch point 35 of the flow path 33. The water circuit on-off valve 42 connects the upstream branch point 34 and the downstream branch point 35 to allow water to flow through the flow path 45, or blocks the flow path 45 to prevent water from flowing through it. The upstream on-off valve 43 is provided between the upstream branch point 34 of the thermal storage flow path 32 and the hot water thermal storage tank 41. The upstream on-off valve 43 connects the upstream branch point 34 and the hot water thermal storage tank 41 to allow water to flow into the thermal storage flow path 32, and blocks the thermal storage flow path 32 to prevent water from flowing into the flow path 33. The downstream on-off valve 44 is provided in the thermal storage flow path 32 between the hot water thermal storage tank 41 and the downstream branch point 35. The downstream on-off valve 44 connects the hot water thermal storage tank 41 and the downstream branch point 35 to allow water to flow into the thermal storage flow path 32, and blocks the thermal storage flow path 32 to prevent water from flowing into the thermal storage flow path 32.

The heat storage tank circuit 31 further includes a stored water temperature sensor 46 (first temperature sensor). The stored water temperature sensor 46 measures the temperature of the water stored in the hot water heat storage tank 41.

Figure 2 is a block diagram showing the air conditioner 1 of Example 1. The air conditioner 1 further includes a control device 51 (control unit). The control device 51 is a computer, and includes a storage device 52 and a CPU (Central Processing Unit) 53 (not shown). The storage device 52 stores computer programs installed in the control device 51 and stores information used by the CPU 53. The CPU 53 processes information and controls the storage device 52 by executing the computer programs installed in the control device 51.

The control device 51 also controls the compressor 11, four-way valve 12, pump 21, indoor heat exchanger circulating water temperature sensor 23, intermediate heat exchanger circulating water temperature sensor 24, pooled water temperature sensor 46, water circuit on-off valve 42, upstream on-off valve 43, and downstream on-off valve 44. The temperature difference threshold and replacement time are recorded in the memory device 52.

The operations performed by the air conditioner 1 include heating operation, cooling operation, and interior cleaning operation.

[Heating operation]
The heating operation is performed, for example, when the air conditioner 1 is operated by a user. When the air conditioner 1 performs the heating operation, the control device 51 switches the four-way valve 12 to the heating position. The control device 51 controls the compressor 11 to compress the low-temperature, low-pressure gas-phase refrigerant supplied via the suction pipe 17. The low-temperature, low-pressure gas-phase refrigerant changes state to high-temperature, high-pressure gas-phase refrigerant by being compressed by the compressor 11. The compressor 11 discharges the high-temperature, high-pressure gas-phase refrigerant to the discharge pipe 18. Because the four-way valve 12 is switched to the heating position, it supplies the high-temperature, high-pressure gas-phase refrigerant discharged to the discharge pipe 18 to the intermediate heat exchanger 16.

The intermediate heat exchanger 16 exchanges heat between the high-temperature, high-pressure gas-phase refrigerant supplied from the four-way valve 12 and the water circulating through the water circuit 6, heating the water and cooling the high-temperature, high-pressure gas-phase refrigerant. The high-temperature, high-pressure gas-phase refrigerant is cooled by the intermediate heat exchanger 16, changing its state to a supercooled high-temperature, high-pressure liquid-phase refrigerant. In other words, the intermediate heat exchanger 16 functions as a condenser when the air conditioner 1 performs heating operation. The high-temperature, high-pressure liquid-phase refrigerant is supplied to the expansion valve 15.

The expansion valve 15 adjusts the flow rate of refrigerant flowing from the intermediate heat exchanger 16 to the outdoor heat exchanger 14, reducing the pressure of the high-temperature, high-pressure liquid-phase refrigerant supplied from the outdoor heat exchanger 14. By reducing the pressure, the high-temperature, high-pressure liquid-phase refrigerant changes state to a low-temperature, low-pressure, two-phase gas-liquid refrigerant with a high humidity level. The low-temperature, low-pressure, two-phase gas-liquid refrigerant with a high humidity level is supplied to the outdoor heat exchanger 14.

The outdoor heat exchanger 14 exchanges heat between the low-temperature, low-pressure, two-phase gas-liquid refrigerant supplied from the expansion valve 15 and the outside air, heating the low-temperature, low-pressure, two-phase gas-liquid refrigerant and cooling the outside air. When the low-temperature, low-pressure, two-phase gas-liquid refrigerant is heated, it changes state to low-temperature, low-pressure, gas-phase refrigerant. In other words, the outdoor heat exchanger 14 functions as an evaporator when the air conditioner 1 performs heating operation. The low-temperature, low-pressure, gas-phase refrigerant is supplied to the four-way valve 12. When the four-way valve 12 is switched to the heating position, it supplies the low-temperature, low-pressure, gas-phase refrigerant supplied from the outdoor heat exchanger 14 to the suction pipe 17, which then supplies the low-temperature, low-pressure, gas-phase refrigerant to the compressor 11 via the suction pipe 17.

When the air conditioner 1 performs heating operation, the control device 51 opens the water circuit on-off valve 42 and connects the upstream branch point 34 and the downstream branch point 35 so that water flows into the flow path 45. The control device 51 also closes the upstream on-off valve 43 and the downstream on-off valve 44 to block the heat storage flow path 32 so that water does not flow into the heat storage flow path 32. In other words, when the air conditioner 1 performs heating operation, the control device 51 controls the opening and closing of the water circuit on-off valve 42, the upstream on-off valve 43, and the downstream on-off valve 44, and isolates the hot water heat storage tank 41 from the water circuit 6 so that water circulating through the water circuit 6 is not supplied to the hot water heat storage tank 41, and water stored in the hot water heat storage tank 41 is not supplied to the water circuit 6. When the hot water thermal storage tank 41 is separated from the water circuit 6, heat from the outside air is transferred to the water stored in the hot water thermal storage tank 41, and the temperature of the water stored in the hot water thermal storage tank 41 approaches the temperature of the outside air.

After the hot water thermal storage tank 41 is separated from the water circuit 6, the control device 51 controls the pump 21 to supply the water supplied from the intermediate heat exchanger 16 to the indoor heat exchanger 22 so that the water circulates through the water circuit 6. The indoor heat exchanger 22 exchanges heat between the water supplied from the pump 21 and the air in the room where the indoor unit 3 is installed, cooling the water and heating the air in the room. The water cooled by the indoor heat exchanger 22 is supplied to the intermediate heat exchanger 16. The indoor unit 3 heats the room by the indoor heat exchanger 22 cooling the air in the room.

When the air conditioner 1 is performing heating operation, the hot water thermal storage tank 41 is separated from the water circuit 6, so the refrigerant in the refrigerant circuit 5 does not heat the water stored in the hot water thermal storage tank 41, but rather the refrigerant in the refrigerant circuit 5 heats only the water circulating through the water circuit 6. By using the refrigerant in the refrigerant circuit 5 to heat only the water circulating through the water circuit 6, the air conditioner 1 can quickly increase the temperature of the water circulating through the water circuit 6. By quickly increasing the temperature of the water circulating through the water circuit 6, the air conditioner 1 can shorten the time from when heating operation is started until the room is heated.

[Cooling operation]
The cooling operation is performed, for example, when the air conditioner 1 is operated by a user. When the air conditioner 1 performs the cooling operation, the control device 51 controls the four-way valve 12 and switches the four-way valve 12 to the cooling position. The control device 51 controls the compressor 11 to compress the low-temperature, low-pressure gas-phase refrigerant supplied via the suction pipe 17. The low-temperature, low-pressure gas-phase refrigerant changes state to high-temperature, high-pressure gas-phase refrigerant by being compressed by the compressor 11. The compressor 11 discharges the high-temperature, high-pressure gas-phase refrigerant to the discharge pipe 18. Because the four-way valve 12 is switched to the cooling position, the high-temperature, high-pressure gas-phase refrigerant discharged to the discharge pipe 18 is supplied to the outdoor heat exchanger 14.

The outdoor heat exchanger 14 exchanges heat between the high-temperature, high-pressure gas refrigerant supplied from the four-way valve 12 and outside air, cooling the high-temperature, high-pressure gas refrigerant and heating the outside air. By being cooled, the high-temperature, high-pressure gas refrigerant changes state to a supercooled high-temperature, high-pressure liquid refrigerant. In other words, the outdoor heat exchanger 14 functions as a condenser when the air conditioner 1 performs cooling operation. The high-temperature, high-pressure liquid refrigerant is supplied to the expansion valve 15.

The expansion valve 15 adjusts the flow rate of refrigerant flowing from the outdoor heat exchanger 14 to the intermediate heat exchanger 16, reducing the pressure of the high-temperature, high-pressure liquid-phase refrigerant supplied from the outdoor heat exchanger 14. By reducing the pressure, the high-temperature, high-pressure liquid-phase refrigerant changes state to a low-temperature, low-pressure, two-phase gas-liquid refrigerant. The low-temperature, low-pressure, two-phase gas-liquid refrigerant is supplied to the intermediate heat exchanger 16.

The intermediate heat exchanger 16 exchanges heat between the low-temperature, low-pressure, two-phase gas-liquid refrigerant supplied from the expansion valve 15 and the water circulating through the water circuit 6, cooling the water and heating the low-temperature, low-pressure, two-phase gas-liquid refrigerant. The low-temperature, low-pressure, two-phase gas-liquid refrigerant changes state to low-temperature, low-pressure, gas-phase refrigerant when heated by the intermediate heat exchanger 16. In other words, the intermediate heat exchanger 16 functions as an evaporator when the air conditioner 1 performs cooling operation. The low-temperature, low-pressure, gas-phase refrigerant is supplied to the four-way valve 12. Because the four-way valve 12 is switched to the cooling position, the low-temperature, low-pressure, gas-phase refrigerant supplied from the intermediate heat exchanger 16 is supplied to the compressor 11 via the suction pipe 17.

When the air conditioner 1 performs cooling operation, the control device 51 opens the water circuit on-off valve 42 and connects the upstream branch point 34 and the downstream branch point 35 so that water flows into the flow path 45. The control device 51 also closes the upstream on-off valve 43 and the downstream on-off valve 44 to block the heat storage flow path 32 so that water does not flow into the heat storage flow path 32. In other words, when the air conditioner 1 performs cooling operation, the control device 51 controls the opening and closing of the water circuit on-off valve 42, the upstream on-off valve 43, and the downstream on-off valve 44, and isolates the hot water heat storage tank 41 from the water circuit 6 so that water circulating through the water circuit 6 is not supplied to the hot water heat storage tank 41, and water stored in the hot water heat storage tank 41 is not supplied to the water circuit 6. When the hot water thermal storage tank 41 is separated from the water circuit 6, heat from the outside air is transferred to the water stored in the hot water thermal storage tank 41, and the temperature of the water stored in the hot water thermal storage tank 41 approaches the temperature of the outside air.

After the hot water thermal storage tank 41 is separated from the water circuit 6, the control device 51 controls the pump 21 to supply the water supplied from the intermediate heat exchanger 16 to the indoor heat exchanger 22 so that the water circulates through the water circuit 6. The indoor heat exchanger 22 exchanges heat between the water supplied from the pump 21 and the air in the room where the indoor unit 3 is installed, heating the water and cooling the air in the room. The water heated by the indoor heat exchanger 22 is supplied to the intermediate heat exchanger 16. The indoor unit 3 cools the room by the indoor heat exchanger 22 cooling the air in the room.

When the air conditioner 1 is operating in cooling mode, the hot water thermal storage tank 41 is separated from the water circuit 6, so that the refrigerant in the refrigerant circuit 5 does not cool the water stored in the hot water thermal storage tank 41, but rather the refrigerant in the refrigerant circuit 5 cools only the water circulating through the water circuit 6. By having the refrigerant in the refrigerant circuit 5 cool only the water circulating through the water circuit 6, the air conditioner 1 can quickly lower the temperature of the water circulating through the water circuit 6. By quickly lowering the temperature of the water circulating through the water circuit 6, the air conditioner 1 can shorten the time from when cooling mode is started until the room is cooled.

[Internal clean operation]
The interior cleaning operation is performed, for example, when the air conditioner 1 is operated by a user, or automatically after the cooling operation has ended. Before the interior cleaning operation is started, the control device 51 controls the pump 21 to supply water from the intermediate heat exchanger 16 to the indoor heat exchanger 22 so that the water circulates through the water circuit 6. The control device 51 also measures the stored water temperature using the stored water temperature sensor 46, and measures the circulating water temperature using the indoor heat exchanger circulating water temperature sensor 23 or the intermediate heat exchanger circulating water temperature sensor 24. The stored water temperature indicates the temperature of the water stored in the hot water thermal storage tank 41. The circulating water temperature indicates the temperature of the water circulating through the water circuit 6.

The control device 51 determines whether the temperature difference obtained by subtracting the circulating water temperature from the stored water temperature is greater than the temperature difference threshold stored in the memory device 52. When the temperature difference is greater than the temperature difference threshold, the control device 51 opens the upstream on-off valve 43 and the downstream on-off valve 44 to allow water to flow into the heat storage flow path 32, and closes the water circuit on-off valve 42 to block flow path 45 so that water does not flow into it. That is, the control device 51 controls the opening and closing of the water circuit on-off valve 42, the upstream on-off valve 43, and the downstream on-off valve 44 to connect the hot water heat storage tank 41 to the water circuit 6 so that water circulating through the water circuit 6 flows through the hot water heat storage tank 41. Because the hot water heat storage tank 41 is connected to the water circuit 6, the water circulating through the water circuit 6 flows from the upstream branch point 34 into the heat storage flow path 32 and is stored in the hot water heat storage tank 41. When water circulating through the water circuit 6 flows into the heat storage flow path 32, the water stored in the hot water thermal storage tank 41 is pushed out of the hot water thermal storage tank 41 by the water supplied to the hot water thermal storage tank 41 and supplied to the water circuit 6. When the replacement time recorded in the memory device 52 has elapsed since the hot water thermal storage tank 41 was connected to the water circuit 6, the change in water temperature caused by the supply of water from the hot water thermal storage tank 41 to the water circuit 6 settles down. Here, the replacement time recorded in the memory device 52 is a value determined in advance through testing, etc.

When the replacement time has elapsed since the hot water thermal storage tank 41 was connected to the water circuit 6, the control device 51 opens the water circuit on-off valve 42 to allow water to flow through the flow path 45, and closes the upstream on-off valve 43 and downstream on-off valve 44 to prevent water from flowing through the thermal storage flow path 32. In other words, when the replacement time has elapsed since the hot water thermal storage tank 41 was connected to the water circuit 6, the control device 51 controls the opening and closing of the water circuit on-off valve 42, upstream on-off valve 43, and downstream on-off valve 44 to isolate the hot water thermal storage tank 41 from the water circuit 6.

Internal clean operation is initiated when the temperature difference between the stored water temperature and the circulating water temperature is smaller than the temperature difference threshold, or after the replacement time has elapsed since the hot water thermal storage tank 41 was connected to the water circuit 6, and after the hot water thermal storage tank 41 is separated from the water circuit 6. When internal clean operation is initiated, the control device 51 controls the compressor 11 to compress the low-temperature, low-pressure gas-phase refrigerant supplied via the suction pipe 17. The low-temperature, low-pressure gas-phase refrigerant is compressed by the compressor 11, changing its state to high-temperature, high-pressure gas-phase refrigerant. The compressor 11 discharges the high-temperature, high-pressure gas-phase refrigerant to the discharge pipe 18. Because the four-way valve 12 is switched to the heating position, the high-temperature, high-pressure gas-phase refrigerant discharged to the discharge pipe 18 is supplied to the intermediate heat exchanger 16.

The intermediate heat exchanger 16 exchanges heat between the high-temperature, high-pressure gas-phase refrigerant supplied from the four-way valve 12 and the water circulating through the water circuit 6, heating the water and cooling the high-temperature, high-pressure gas-phase refrigerant. The high-temperature, high-pressure gas-phase refrigerant is cooled by the intermediate heat exchanger 16, changing its state to a supercooled high-temperature, high-pressure liquid-phase refrigerant. In other words, the intermediate heat exchanger 16 functions as a condenser when the air conditioner 1 performs internal clean operation. The high-temperature, high-pressure liquid-phase refrigerant is supplied to the expansion valve 15.

The expansion valve 15 adjusts the flow rate of refrigerant flowing from the intermediate heat exchanger 16 to the outdoor heat exchanger 14, reducing the pressure of the high-temperature, high-pressure liquid-phase refrigerant supplied from the outdoor heat exchanger 14. By reducing the pressure, the high-temperature, high-pressure liquid-phase refrigerant changes state to a low-temperature, low-pressure, two-phase gas-liquid refrigerant with a high humidity level. The low-temperature, low-pressure, two-phase gas-liquid refrigerant with a high humidity level is supplied to the outdoor heat exchanger 14.

The outdoor heat exchanger 14 exchanges heat between the low-temperature, low-pressure, two-phase gas-liquid refrigerant supplied from the expansion valve 15 and outside air, heating the low-temperature, low-pressure, two-phase gas-liquid refrigerant and cooling the outside air. When the low-temperature, low-pressure, two-phase gas-liquid refrigerant is heated, it changes state to low-temperature, low-pressure, gas-phase refrigerant. In other words, the outdoor heat exchanger 14 functions as an evaporator when the air conditioner 1 performs internal clean operation. The low-temperature, low-pressure, gas-phase refrigerant is supplied to the four-way valve 12. When the four-way valve 12 is switched to the heating position, the low-temperature, low-pressure, gas-phase refrigerant supplied from the outdoor heat exchanger 14 is supplied to the suction pipe 17, which then supplies the low-temperature, low-pressure, gas-phase refrigerant to the compressor 11 via the suction pipe 17. In other words, when internal clean operation is being performed, refrigerant circulates through the refrigerant circuit 5 in the same way as when heating operation is being performed.

Water heated by the intermediate heat exchanger 16 is supplied to the indoor heat exchanger 22 as the water circulates through the water circuit 6. The indoor heat exchanger 22 is heated by supplying heated water to the indoor heat exchanger 22. Condensed water that condenses on the indoor heat exchanger 22 during cooling operation is heated by heating the indoor heat exchanger 22. Bacteria and mold adhering to the indoor unit 3 are sterilized by heating the condensed water. After sterilization, the indoor unit 3 is dried by heating the indoor heat exchanger 22. By drying the indoor unit 3, the air conditioner 1 can prevent the growth of bacteria and mold in the indoor unit 3.

In other words, when the air conditioner 1 is performing internal cleaning operation and warm water is stored in the hot water thermal storage tank 41, it can supply that warm water to the water circuit 6, thereby raising the temperature of the water circulating through the water circuit 6 in a short period of time. When the air conditioner 1 is performing internal cleaning operation, it can reduce the power consumed to raise the temperature of the water circulating through the water circuit 6. Furthermore, by raising the temperature of the water circulating through the water circuit 6 in a short period of time, the air conditioner 1 can shorten the time from when the internal cleaning operation is started until the indoor heat exchanger 22 is heated.

[Effects of the air conditioner 1 according to the first embodiment]
The air conditioner 1 of Example 1 includes a refrigerant circuit 5, a water circuit 6, an intermediate heat exchanger 16, an indoor heat exchanger 22, a hot water thermal storage tank 41, a water circuit on-off valve 42, an upstream on-off valve 43, a downstream on-off valve 44, and a control device 51. Refrigerant circulates through the refrigerant circuit 5. Water circulates through the water circuit 6. The intermediate heat exchanger 16 exchanges heat between the refrigerant and the water. The indoor heat exchanger 22 exchanges heat between the water and indoor air. Water is stored in the hot water thermal storage tank 41. The water circuit on-off valve 42, the upstream on-off valve 43, and the downstream on-off valve 44 connect the hot water thermal storage tank 41 and the water circuit 6 or disconnect the hot water thermal storage tank 41 and the water circuit 6. The control device 51 controls the opening and closing of the water circuit on-off valve 42, the upstream on-off valve 43, and the downstream on-off valve 44.

By connecting the hot water thermal storage tank 41 to the water circuit 6, the air conditioner 1 of Example 1 supplies water stored in the hot water thermal storage tank 41 to the water circuit 6, and can raise or lower the temperature of the water circulating through the water circuit 6 without using the heat of the refrigerant to heat or cool the water in the water circuit 6. By separating the hot water thermal storage tank 41 from the water circuit 6, the air conditioner 1 of Example 1 uses the refrigerant in the refrigerant circuit 5 to heat or cool only the water circulating through the water circuit 6, without heat exchange between the refrigerant in the refrigerant circuit 5 and the water stored in the hot water thermal storage tank 41. By exchanging heat between the refrigerant in the refrigerant circuit 5 and only the water circulating through the water circuit 6, the air conditioner 1 of Example 1 can raise or lower the temperature of the water circulating through the water circuit 6 in a short period of time. By raising or lowering the temperature of the water circulating through the water circuit 6 in a short period of time, the air conditioner 1 of Example 1 can reduce power consumption.

Furthermore, when switching from cooling operation to internal cleaning operation, the control device 51 of the air conditioner 1 of Example 1 controls the opening and closing of the water circuit on-off valve 42, the upstream on-off valve 43, and the downstream on-off valve 44 so that the hot water thermal storage tank 41 and the water circuit 6 are connected. The air conditioner 1 of Example 1 can increase the temperature of the water circulating through the water circuit 6 in a short period of time by supplying hot water stored in the hot water thermal storage tank 41 to the water circuit 6. The air conditioner 1 of Example 1 can shorten the operating time during which internal cleaning operation is performed by increasing the temperature of the water circulating through the water circuit 6 in a short period of time.

Furthermore, the control device 51 of the air conditioner 1 of Example 1 controls the opening and closing of the water circuit on-off valve 42, the upstream on-off valve 43, and the downstream on-off valve 44 so that the hot water thermal storage tank 41 and the water circuit 6 are shut off when the internal cleaning operation is performed. Because the hot water thermal storage tank 41 is separated from the water circuit 6, the air conditioner 1 of Example 1 does not heat the water stored in the hot water thermal storage tank 41 using the refrigerant in the refrigerant circuit 5, but instead uses the refrigerant in the refrigerant circuit 5 to heat only the water circulating through the water circuit 6. Because the air conditioner 1 of Example 1 uses the refrigerant in the refrigerant circuit 5 to heat only the water circulating through the water circuit 6, the temperature of the water circulating through the water circuit 6 can be raised in a short period of time. Because the temperature of the water circulating through the water circuit 6 rises in a short period of time, the air conditioner 1 of Example 1 can shorten the operating time during which the internal cleaning operation is performed.

The air conditioner 1 of Example 1 also includes a stored water temperature sensor 46 that measures the temperature of water stored in the hot water thermal storage tank 41, and an indoor heat exchanger circulating water temperature sensor 23 and an intermediate heat exchanger circulating water temperature sensor 24 that measure the temperature of water circulating through the water circuit 6. When the temperature difference is greater than the temperature difference threshold, the control device 51 controls the opening and closing of the water circuit on-off valve 42, the upstream on-off valve 43, and the downstream on-off valve 44 so that water stored in the hot water thermal storage tank 41 is supplied to the water circuit 6. This temperature difference represents the value obtained by subtracting the circulating water temperature measured by the indoor heat exchanger circulating water temperature sensor 23 or the intermediate heat exchanger circulating water temperature sensor 24 from the stored water temperature measured by the stored water temperature sensor 46. When the temperature difference is smaller than the temperature difference threshold, the control device 51 controls the opening and closing of the water circuit on-off valve 42, the upstream on-off valve 43, and the downstream on-off valve 44 so as to cut off the connection between the hot water thermal storage tank 41 and the water circuit 6.

The temperature of the water circulating through the water circuit 6 does not change significantly when the water stored in the hot water thermal storage tank 41 replaces the water circulating through the water circuit 6 when the temperature difference is smaller than the temperature difference threshold. The air conditioner 1 of Example 1 replaces the water circulating through the water circuit 6 with the water stored in the hot water thermal storage tank 41 only when the temperature difference is larger than the temperature difference threshold, thereby enabling the temperature of the water circulating through the water circuit 6 to change significantly in a short period of time and reducing power consumption.

Incidentally, the hot water thermal storage tank 41 of the air conditioner 1 of Example 1 described above is separated from the water circuit 6 when heating or cooling operation is performed, but it may also be connected to the water circuit 6 before heating or cooling operation is performed. For example, when heating operation is started and the stored water temperature is higher than the circulating water temperature, the air conditioner replaces the water circulating through the water circuit 6 with the water stored in the hot water thermal storage tank 41. After the water circulating through the water circuit 6 is replaced with the water stored in the hot water thermal storage tank 41, the air conditioner separates the hot water thermal storage tank 41 from the water circuit 6. After the hot water thermal storage tank 41 is separated from the water circuit 6, the air conditioner performs heating operation, similar to the air conditioner 1 of Example 1 described above. At this time, the air conditioner replaces the water circulating through the water circuit 6 with the water stored in the hot water thermal storage tank 41, thereby enabling the temperature of the water circulating through the water circuit 6 to rise to a predetermined temperature or higher in a short period of time. The air conditioner 1 can reduce the power consumed to heat the water circulating through the water circuit 6. Furthermore, by quickly raising the temperature of the water circulating through the water circuit 6, the air conditioner 1 can shorten the time it takes for the room to be heated after heating operation is started.

Furthermore, when cooling operation is initiated and the stored water temperature is lower than the circulating water temperature, the air conditioner replaces the water circulating through the water circuit 6 with the water stored in the hot water thermal storage tank 41. After the water circulating through the water circuit 6 has been replaced with the water stored in the hot water thermal storage tank 41, the air conditioner separates the hot water thermal storage tank 41 from the water circuit 6. After the hot water thermal storage tank 41 has been separated from the water circuit 6, the air conditioner performs cooling operation, similar to the air conditioner 1 of Example 1 described above. At this time, by replacing the water circulating through the water circuit 6 with the water stored in the hot water thermal storage tank 41, the air conditioner can quickly lower the temperature of the water circulating through the water circuit 6 to below a predetermined temperature. The air conditioner 1 can reduce the power consumed to lower the temperature of the water circulating through the water circuit 6. Furthermore, the air conditioner 1 reduces the temperature of the water circulating through the water circuit 6 in a short time, thereby shortening the time it takes for the room to be cooled after cooling operation begins.

Incidentally, the air conditioner 1 of the above-described first embodiment uses the replacement time to determine the timing to separate the hot water thermal storage tank 41 from the water circuit 6 before the internal cleaning operation is started. However, this timing may be determined without using the replacement time. For example, the control device 51 separates the hot water thermal storage tank 41 from the water circuit 6 when the circulating water temperature measured by the indoor heat exchanger circulating water temperature sensor 23 becomes higher than the stored water temperature measured by the stored water temperature sensor 46. Even when the hot water thermal storage tank 41 is separated from the water circuit 6 at this timing, the air conditioner 1 can quickly increase the temperature of the water circulating through the water circuit 6, thereby shortening the operating time during which the internal cleaning operation is performed.

Incidentally, the water circuit on-off valve 42, upstream on-off valve 43, and downstream on-off valve 44 of the air conditioner 1 in the previously described first embodiment are formed from on-off valves, but they may also be formed from a single four-way valve. Even if the water circuit on-off valve 42, upstream on-off valve 43, and downstream on-off valve 44 are formed from a single four-way valve, the air conditioner 1 can similarly increase the temperature of the water circulating through the water circuit 6 in a short period of time.

Figure 3 is a circuit diagram showing an air conditioner 61 of Example 2. The air conditioner 61 of Example 2 is identical to the air conditioner 1 of Example 1 described above, except that the heat storage tank circuit 31 of the air conditioner 1 of Example 1 described above is replaced with another heat storage tank circuit 62. The heat storage tank circuit 62 is disposed inside the outdoor unit 2. The heat storage tank circuit 62 includes a heat storage tank circuit branch 63, an upstream flow path 64, a hot-side flow path 65, and a cold-side flow path 66. One end of the upstream flow path 64 is connected to the upstream branch point 34. The other end of the upstream flow path 64 is connected to the heat storage tank circuit branch 63. One end of the hot-side flow path 65 is connected to the heat storage tank circuit branch 63. The other end of the hot-side flow path 65 is connected to the downstream branch point 35. One end of the cold-side flow path 66 is connected to the heat storage tank circuit branch 63. The other end of the cold-side flow path 66 is connected to the downstream branch point 35.

The heat storage tank circuit 62 includes a hot tank 71 (heat storage tank), a cold tank 72 (another heat storage tank), an upstream on-off valve 73, a hot-side on-off valve 74 (valve), and a cold-side on-off valve 75 (another valve). The hot tank 71 is located midway along the hot-side flow path 65 and stores water flowing through the hot-side flow path 65. The cold tank 72 is located midway along the cold-side flow path 66 and stores water flowing through the cold-side flow path 66. The cold tank 72 includes insulation 77. The insulation 77 surrounds the cold tank 72 and prevents heat from the outside air from being transferred to the water stored in the cold tank 72. The hot tank 71 does not include insulation. For this reason, the insulating performance of the cold tank 72, which prevents the heat of the outside air from being transferred to the water stored in the cold tank 72, is higher than the insulating performance of the hot tank 71, which prevents the heat of the outside air from being transferred to the water stored in the hot tank 71. In other words, the heat transfer performance of the hot tank 71, which transfers the heat of the outside air to the water stored in the hot tank 71, is higher than the heat transfer performance of the cold tank 72, which transfers the heat of the outside air to the water stored in the cold tank 72.

The upstream on-off valve 73 is provided midway along the upstream flow path 64. The upstream on-off valve 73 connects the upstream branch point 34 and the heat storage tank circuit branch point 63 to allow water to flow into the upstream flow path 64, and blocks the upstream flow path 64 to prevent water from flowing into it. The hot side on-off valve 74 is provided midway along the hot side flow path 65. The hot side on-off valve 74 connects the heat storage tank circuit branch point 63 and the downstream branch point 35 to allow water to flow into the hot side flow path 65, and blocks the hot side flow path 65 to prevent water from flowing into it. The cold side on-off valve 75 is provided midway along the cold side flow path 66. The cold side on-off valve 75 connects the heat storage tank circuit branch point 63 and the downstream branch point 35 to allow water to flow into the cold side flow path 66, and blocks the cold side flow path 66 to prevent water from flowing into it.

When the air conditioner 61 performs heating operation, the control device 51 controls the compressor 11, four-way valve 12, and pump 21 in the same manner as when the air conditioner 1 of Example 1 performs heating operation. When the air conditioner 61 performs heating operation, the water stored in the thermal tank 71 is cooled to approach the temperature of the outside air by heat transfer from the outside air. When the air conditioner 61 performs cooling operation, the control device 51 controls the compressor 11, four-way valve 12, and pump 21 in the same manner as when the air conditioner 1 of Example 1 performs cooling operation. When the air conditioner 61 performs cooling operation, the water stored in the thermal tank 71 is heated to approach the temperature of the outside air by heat transfer from the outside air.

When switching from cooling operation to internal cleaning operation and before internal cleaning operation is performed, the control device 51 controls the pump 21 to supply water supplied from the intermediate heat exchanger 16 to the indoor heat exchanger 22 so that the water circulates through the water circuit 6. The control device 51 opens the upstream on-off valve 73 and the cold side on-off valve 75 to allow the cold water circulating through the water circuit 6 to flow into the cold side flow path 66. The control device 51 closes the hot side on-off valve 74 to block the hot side flow path 65 so that the cold water circulating through the water circuit 6 does not flow into the hot side flow path 65. The control device 51 closes the water circuit on-off valve 42 to block flow path 45 so that the cold water circulating through the water circuit 6 does not flow into flow path 45. That is, the control device 51 controls the opening of the water circuit on-off valve 42, the upstream on-off valve 73, the hot side on-off valve 74, and the cold side on-off valve 75 to separate the hot tank 71 from the water circuit 6 and connect the cold tank 72 to the water circuit 6. By connecting the cold tank 72 to the water circuit 6, the cold water circulating through the water circuit 6 is stored in the cold tank 72, and the water stored in the cold tank 72 is pushed out of the cold tank 72 by the cold water and supplied to the water circuit 6.

After the cold water circulating through the water circuit 6 is stored in the cold tank 72, the control device 51 opens the upstream on-off valve 73 and the hot side on-off valve 74, allowing the water circulating through the water circuit 6 to flow into the hot side flow path 65. The control device 51 closes the cold side on-off valve 75 and blocks the cold side flow path 66 so that the water circulating through the water circuit 6 does not flow into it. That is, the control device 51 controls the opening and closing of the water circuit on-off valve 42, the upstream on-off valve 73, the hot side on-off valve 74, and the cold side on-off valve 75 to connect the hot tank 71 to the water circuit 6 and separate the cold tank 72 from the water circuit 6. By connecting the hot tank 71 to the water circuit 6, the water circulating through the water circuit 6 is stored in the hot tank 71, and the hot water stored in the hot tank 71 is pushed out of the hot tank 71 by the water circulating through the water circuit 6 and supplied to the water circuit 6.

After the hot water stored in the hot bath 71 is supplied to the water circuit 6, the control device 51 opens the water circuit on-off valve 42, allowing the water circulating through the water circuit 6 to flow into the flow path 45. The control device 51 closes the upstream on-off valve 73, the hot side on-off valve 74, and the cold side on-off valve 75, blocking the hot side flow path 65 and the cold side flow path 66 so that the water circulating through the water circuit 6 does not flow into these paths. In other words, the control device 51 controls the opening and closing of the water circuit on-off valve 42, the upstream on-off valve 73, the hot side on-off valve 74, and the cold side on-off valve 75, isolating the hot bath 71 and the cold bath 72 from the water circuit 6.

The internal cleaning operation is performed after the hot tank 71 and cold tank 72 are separated from the water circuit 6. When the air conditioner 61 performs the internal cleaning operation, the control device 51 controls the compressor 11, four-way valve 12, and pump 21 in the same way as when the air conditioner 1 of the first embodiment performs the internal cleaning operation.

Before the internal cleaning operation is performed, the air conditioner 61 supplies the hot water stored in the thermal tank 71 to the water circuit 6, thereby quickly raising the temperature of the water circulating through the water circuit 6. The air conditioner 61 can reduce the power consumed to raise the temperature of the water circulating through the water circuit 6 when the internal cleaning operation is performed. Furthermore, by quickly raising the temperature of the water circulating through the water circuit 6, the air conditioner 61 can shorten the time from when the internal cleaning operation is started until the indoor heat exchanger 22 is heated.

When switching from internal cleaning operation to cooling operation, the control device 51 opens the upstream on-off valve 73 and the hot side on-off valve 74, allowing the water circulating through the water circuit 6 to flow into the hot side flow path 65. The control device 51 closes the cold side on-off valve 75 and blocks the cold side flow path 66 so that the water circulating through the water circuit 6 does not flow into it. That is, the control device 51 controls the opening and closing of the water circuit on-off valve 42, the upstream on-off valve 73, the hot side on-off valve 74, and the cold side on-off valve 75 to connect the hot tank 71 to the water circuit 6 and separate the cold tank 72 from the water circuit 6. By connecting the hot tank 71 to the water circuit 6, the water circulating through the water circuit 6 is stored in the hot tank 71, and the water stored in the hot tank 71 is pushed out of the hot tank 71 by the water circulating through the water circuit 6 and supplied to the water circuit 6.

After the water circulating through the water circuit 6 is stored in the hot tank 71, the control device 51 opens the upstream on-off valve 73 and the cold side on-off valve 75, allowing the water circulating through the water circuit 6 to flow into the cold side flow path 66. The control device 51 opens the hot side on-off valve 74 and shuts off the hot side flow path 65 so that the water circulating through the water circuit 6 does not flow into it. That is, the control device 51 controls the opening and closing of the water circuit on-off valve 42, the upstream on-off valve 73, the hot side on-off valve 74, and the cold side on-off valve 75 to separate the hot tank 71 from the water circuit 6 and connect the cold tank 72 to the water circuit 6. By connecting the cold tank 72 to the water circuit 6, the water circulating through the water circuit 6 is stored in the cold tank 72, and the cold water stored in the cold tank 72 is pushed out of the cold tank 72 by the water circulating through the water circuit 6 and supplied to the water circuit 6.

The cooling operation, which is performed immediately after the internal cleaning operation, is performed after the hot tank 71 and cold tank 72 are separated from the water circuit 6. When the air conditioner 61 performs the cooling operation, the control device 51 controls the compressor 11, four-way valve 12, and pump 21 in the same way as when the air conditioner 1 of the first embodiment described above performs the cooling operation.

Before cooling operation begins, the air conditioner 61 supplies cold water stored in the cold tank 72 to the water circuit 6, thereby quickly lowering the temperature of the water circulating through the water circuit 6. When cooling operation begins, the air conditioner 61 can reduce the power consumed to lower the temperature of the water circulating through the water circuit 6. Furthermore, by quickly lowering the temperature of the water circulating through the water circuit 6, the air conditioner 61 can shorten the time it takes for the room to be cooled after cooling operation begins.

Incidentally, the water circuit on-off valve 42, upstream on-off valve 73, hot side on-off valve 74, and cold side on-off valve 75 of the air conditioner 61 in the previously described second embodiment are formed from on-off valves, but they may also be formed from two four-way valves. Even if the water circuit on-off valve 42, upstream on-off valve 73, hot side on-off valve 74, and cold side on-off valve 75 are formed from two four-way valves, the air conditioner 61 can similarly change the temperature of the water circulating through the water circuit 6 in a short period of time.

Although the embodiments have been described above, the embodiments are not limited to the above content. Furthermore, the components described above include those that would be easily conceivable by a person skilled in the art, those that are substantially the same, and those that are within the scope of what is known as equivalents. Furthermore, the components described above can be combined as appropriate. Furthermore, at least one of various omissions, substitutions, and modifications of the components can be made without departing from the spirit of the embodiments.

1: Air conditioner 5: Refrigerant circuit (first circuit)
6: Water circuit (second circuit)
11: Compressor 12: Four-way valve 14: Outdoor heat exchanger 15: Expansion valve 16: Intermediate heat exchanger 21: Pump 22: Indoor heat exchanger 23: Indoor heat exchanger circulating water temperature sensor (second temperature sensor)
24: Intermediate heat exchanger circulating water temperature sensor (second temperature sensor)
41: Hot water heat storage tank (heat storage tank)
42: Water circuit on-off valve (valve)
43: Upstream on-off valve (valve)
44: Downstream on-off valve (valve)
46: Reservoir water temperature sensor (first temperature sensor)
51: Control device (control unit)
61: Air conditioner 71: Heat tank (heat storage tank)
72: Cold and heat tank (other heat storage tank)
73: Upstream on-off valve (valve)
74: Heating side opening/closing valve (valve)
75: Cold side opening/closing valve (other valve)

Claims (7)

a first circuit through which a first refrigerant circulates;
a second circuit in which a second refrigerant different from the first refrigerant circulates;
a heat exchanger that exchanges heat between the first refrigerant and the second refrigerant;
an indoor heat exchanger that exchanges heat between the second refrigerant and indoor air;
a heat storage tank in which a portion of the second refrigerant is stored;
a valve that connects the heat storage tank and the second circuit and that disconnects the heat storage tank and the second circuit;
a control unit that controls the valve,
The control unit controls the valve so that the heat storage tank and the second circuit are connected when switching from a cooling operation in which the indoor air is cooled to an interior cleaning operation in which the indoor heat exchanger is heated. The air conditioner according to claim 1, wherein the control unit controls the valve so that the heat storage tank and the second circuit are disconnected when the interior cleaning operation is performed. The air conditioner according to claim 1 or 2, wherein the control unit controls the valve so that the heat storage tank and the second circuit are connected when switching from the interior cleaning operation to the cooling operation. The air conditioner according to claim 3 , wherein the control unit controls the valve so that the heat storage tank and the second circuit are disconnected when the cooling operation is performed. a first temperature sensor that measures a first temperature of a portion of the second refrigerant stored in the heat storage tank;
a second temperature sensor that measures a second temperature of a portion of the second refrigerant circulating through the second circuit;
5. The air conditioner according to claim 1, wherein the control unit controls the valve to supply the second refrigerant stored in the heat storage tank to the second circuit when a temperature difference between the first temperature and the second temperature is greater than a threshold value, and to disconnect the heat storage tank from the second circuit when the temperature difference is smaller than the threshold value. Another heat storage tank in which a portion of the second refrigerant is stored;
further comprising another valve that connects the other heat storage tank to the second circuit or cuts off the connection between the other heat storage tank and the second circuit,
The air conditioner according to any one of claims 1 to 5, wherein the control unit further controls the other valves. 7. The air conditioner according to claim 6, wherein the heat transfer performance of the other heat storage tank that transfers the heat of outside air to a portion of the second refrigerant stored in the other heat storage tank is higher than the heat transfer performance of the heat storage tank that transfers the heat of outside air to a portion of the second refrigerant stored in the heat storage tank.