Heat storage tank and heat storage air conditioning and hot water supply system

Abstract

Provided is a heat storage tank comprising: a heat medium tank storing a heat medium; high-temperature piping connected to an upper portion of the heat medium tank; low-temperature piping connected to a lower portion of the heat medium tank; medium-temperature piping connected to the heat medium tank between the high-temperature piping and the low-temperature piping; a first heat medium pump connected to the high-temperature piping; a second heat medium pump connected to the low-temperature piping; first piping that connects the high-temperature piping with the medium-temperature piping; second piping that connects the first piping with the low-temperature piping; a first channel switching valve connected to the first piping and the second piping; and a second channel switching valve connected to the second piping and the low-temperature piping, wherein low-temperature heat storage operation, high-temperature heat storage operation, heat radiation operation, and simultaneous operation of each of the above are switched by using the first channel switching valve and the second channel switching valve to switch channels of the heat medium flowing inside the high-temperature piping, the medium-temperature piping, and the low-temperature piping.

Description

Heat storage tank and heat storage air conditioning and hot water supply system

[0001] The present disclosure relates to a heat storage tank and a heat storage air conditioning and hot water supply system in the fields of air conditioners, hot water supply equipment, etc.

[0002] Conventionally, there is a thermal storage air conditioning hot water supply system that includes a heat pump refrigeration cycle, a hot water tank, and a cold water tank (see, for example, Patent Document 1). The thermal storage air conditioning hot water supply system of Patent Document 1 stores hot exhaust heat during cooling operation and uses it for hot water supply, or stores cold exhaust heat during hot water heating and uses it for cooling operation, thereby utilizing heat that would be wasted in conventional air conditioners and reducing power consumption.

[0003] Japanese Patent Application Laid-Open No. 2007-255779

[0004] The heat storage air conditioning and hot water supply system of Patent Document 1 requires two pipes each for the forward and return of the heat medium connecting the cold water tank and the hot water tank to the heat source, i.e., a total of four pipes. Due to the large number of pipes and the many construction procedures required for installation, installation was not easy.

[0005] The present disclosure is intended to solve the above-mentioned problems, and aims to provide a heat storage tank and a heat storage air conditioning and hot water supply system that reduces the number of pipes in the heat storage air conditioning and hot water supply system and makes installation easier.

[0006] The heat storage tank according to the present disclosure includes a heat medium tank for storing a heat medium, piping through which the heat medium flows, including a high-temperature piping connected to the top of the heat medium tank, a low-temperature piping connected to the bottom of the heat medium tank, and a medium-temperature piping connected to the heat medium tank between the high-temperature piping and the low-temperature piping in the vertical direction of the heat medium tank, a first heat medium pump connected to the high-temperature piping and causing the heat medium to flow into the heat medium tank and to flow out of the heat medium tank, and a second heat medium pump connected to the low-temperature piping and causing the heat medium to flow into the heat medium tank and to flow out of the heat medium tank. The system includes a pump, a first pipe connecting a high-temperature pipe and a medium-temperature pipe, a second pipe connecting the first pipe and a low-temperature pipe, a first flow path switching valve connected to the first pipe and the second pipe and switching the flow path through which the heat medium flows, and a second flow path switching valve connected to the second pipe and the low-temperature pipe and switching the flow path through which the heat medium flows.The first flow path switching valve and the second flow path switching valve are used to switch the flow path of the heat medium flowing inside the high-temperature pipe, the medium-temperature pipe, and the low-temperature pipe, thereby switching between low-temperature heat storage operation, high-temperature heat storage operation, heat release operation, and simultaneous operation of each.

[0007] The heat storage air conditioning and hot water supply system according to the present disclosure includes the heat storage tank of the above configuration, a plurality of indoor units each having a use-side heat exchanger that exchanges heat between air and a heat medium, a heat medium circulation circuit including at least one of the plurality of indoor units and the heat storage tank, a heating inter-heat medium heat exchanger that heats the heat medium by exchanging heat between a heat source fluid of the heat source unit and the heat medium circulating in the heat medium circulation circuit, a cooling inter-heat medium heat exchanger that cools the heat medium by exchanging heat between the heat source fluid of the heat source unit and the heat medium circulating in the heat medium circulation circuit, a first heat medium circulation pump provided in the heat medium circulation circuit corresponding to the heating inter-heat medium heat exchanger, and a second heat medium circulation pump provided in the heat medium circulation circuit corresponding to the cooling inter-heat medium heat exchanger, and a heat medium circulation pump that connects the indoor units, the heat storage tank, and the heating inter-heat medium heat exchanger and the cooling inter-heat medium heat exchanger. a plurality of heat medium flow switching valves provided in the circuit for switching the connection destination of the indoor unit and the heat storage tank with respect to the heating inter-heat medium heat exchanger and the cooling inter-heat medium heat exchanger; a plurality of heat medium flow control devices provided in the heat medium circulation circuit connecting the indoor unit and the heat storage tank with the heating inter-heat medium heat exchanger and the cooling inter-heat medium heat exchanger and for controlling the flow rate of the heat medium; a plurality of heat medium temperature detection sensors provided in the heat medium circulation circuit connecting the indoor unit and the heat storage tank with the heating inter-heat medium heat exchanger and the cooling inter-heat medium heat exchanger and for detecting the temperature of the heat medium, and based on detection information from the plurality of heat medium temperature detection sensors, the plurality of heat medium flow switching valves and the plurality of heat medium flow control devices are controlled to select cooling, heating, cold heat storage, hot heat storage, hot water supply, or a combination thereof.

[0008] The thermal storage tank and thermal storage air conditioning hot water supply system according to the present disclosure use a first flow path switching valve and a second flow path switching valve to switch the flow path of the heat medium flowing through the high-temperature pipe, the medium-temperature pipe, and the low-temperature pipe, thereby switching between low-temperature heat storage operation, high-temperature heat storage operation, heat release operation, and simultaneous operation of each. Conventionally, thermal storage tanks and thermal storage air conditioning hot water supply systems require two pipes each for the forward and return of the heat medium for low-temperature and high-temperature heat storage and release, i.e., a total of four pipes. The thermal storage tank and thermal storage air conditioning hot water supply system according to the present disclosure uses a high-temperature pipe, a medium-temperature pipe, and a low-temperature pipe, thereby integrating the flow path of the medium-temperature heat medium after heat storage and release into one, thereby reducing the number of pipes. In thermal storage air conditioning hot water supply systems, the thermal storage tank, heat source unit, and heat medium converter are often installed separately, and reducing the number of connecting pipes simplifies and facilitates installation of the thermal storage tank and thermal storage air conditioning hot water supply system.

[0009] FIG. 1 is a schematic diagram showing a heat storage tank according to embodiment 1. FIG. 2 is a circuit diagram showing the flow direction of a circulating medium when storing cold heat in the heat storage tank according to embodiment 1. FIG. 3 is a circuit diagram showing the flow direction of a circulating medium when storing hot heat in the heat storage tank according to embodiment 1. FIG. 4 is a circuit diagram showing the flow direction of a circulating medium when storing hot heat in the heat storage tank according to embodiment 1. FIG. 5 is a circuit diagram showing the flow direction of a circulating medium when simultaneously storing cold and hot heat in the heat storage tank according to embodiment 1. FIG. 6 is a circuit diagram showing the flow direction of a circulating medium when the heat storage tank according to embodiment 1 is operating in hot water supply mode. FIG. 7 is a schematic diagram showing a heat storage tank according to embodiment 2. FIG. 8 is a circuit diagram showing the flow direction of a circulating medium when storing cold heat in the heat storage tank according to embodiment 2. FIG. 9 is a circuit diagram showing the flow direction of a circulating medium when storing hot heat in the heat storage tank according to embodiment 2. FIG. 10 is a circuit diagram showing the flow direction of a circulating medium when storing hot heat in the heat storage tank according to embodiment 2. FIG. 11 is a circuit diagram showing the flow direction of a circulating medium when simultaneously storing cold and hot heat in the heat storage tank according to embodiment 2. FIG. 12 is a circuit diagram showing the flow direction of a circulating medium when simultaneously storing cold and hot heat in the heat storage tank according to embodiment 2. FIG. 13 is a circuit diagram showing the flow direction of a circulating medium when simultaneously storing cold and hot heat in the heat storage tank according to embodiment 2. FIG. 14 is a circuit diagram showing the flow direction of a circulating medium when the heat storage tank according to embodiment 3 is operating in hot water supply mode. FIG. 15 is a schematic diagram showing a heat storage tank according to embodiment 3. Fig. 1 is a schematic diagram of a first example of a heat storage air conditioning and hot water supply system according to embodiment 4. Fig. 2 is a schematic diagram of a second example of a heat storage air conditioning and hot water supply system according to embodiment 4. Fig. 3 is a circuit diagram showing the flow direction of a circulating medium during heat storage utilization heating and cooling operation of a heat storage air conditioning and hot water supply system according to embodiment 4. Fig. 4 is a circuit diagram showing the flow direction of a circulating medium during simultaneous cold and hot heat storage operation of a heat storage air conditioning and hot water supply system according to embodiment 4. Fig. 5 is a circuit diagram showing the flow direction of a circulating medium during simultaneous cold and hot heat storage and simultaneous cooling and heating operation of a heat storage air conditioning and hot water supply system according to embodiment 4.

[0010] Hereinafter, embodiments for carrying out the present disclosure will be described with reference to the drawings. Hereinafter, in the following drawings, including FIG. 1, components denoted with the same reference numerals are identical or equivalent, and are common throughout the following embodiments. In each embodiment, components that are identical or equivalent to those described in the preceding embodiment may be denoted with the same reference numerals, and their description may be omitted. The forms of components shown throughout the specification are merely examples and are not limited to the forms described in the specification. Furthermore, the following embodiments may be partially combined with each other, even if not specifically stated, as long as there is no particular problem with the combination.

[0011] Embodiment 1. [Heat Storage Tank 6] Figure 1 is a schematic diagram showing a heat storage tank 6 according to Embodiment 1. The heat storage tank 6 stores heat generated by a heat source unit. As an example, the heat storage tank 6 is used in a heat storage air conditioning and hot water supply system 200 (see Figure 14), which will be described later. The heat storage tank 6 includes a heat medium tank 72, a high-temperature pipe 81, a low-temperature pipe 83, a medium-temperature pipe 82, a hot water supply heat exchanger 74, a first heat medium pump 31c1, a second heat medium pump 31c2, a first pipe 86, and a second pipe 87. The heat storage tank 6 also includes a first flow path switching valve 32a1 and a second flow path switching valve 32a2. Each component of the heat storage tank 6 described above is described below.

[0012] The heat storage tank 6 includes a heat medium tank 72 that stores a heat medium 91. The heat medium tank 72 stores the heat medium 91 that stores and releases heat. The heat medium 91 can be water, antifreeze, an ethylene glycol solution, or the like. An upper portion 72a of the heat medium tank 72 is a high-temperature heat medium portion where the high-temperature heat medium 91 is stored. A central portion 72b of the heat medium tank 72 is a medium-temperature heat medium portion where the medium-temperature heat medium 91 is stored. A lower portion 72c of the heat medium tank 72 is a low-temperature heat medium portion where the low-temperature heat medium 91 is stored. Normally, natural convection causes high-temperature fluid to rise and low-temperature fluid to descend inside the heat medium tank 72, resulting in the stored heat medium 91 having different temperature distributions depending on the vertical height.

[0013] The heat storage tank 6 includes a high-temperature pipe 81 connected to the upper part 72a of the heat medium tank 72 and a low-temperature pipe 83 connected to the lower part 72c of the heat medium tank 72. The heat storage tank 6 also includes a medium-temperature pipe 82, through which the heat medium 91 flows, connected to the heat medium tank 72 between the high-temperature pipe 81 and the low-temperature pipe 83 in the vertical direction of the heat medium tank 72.

[0014] The high-temperature pipe 81, the medium-temperature pipe 82, and the low-temperature pipe 83 are pipes through which the heat medium 91 flows. The high-temperature pipe 81, the medium-temperature pipe 82, and the low-temperature pipe 83 are connected to three different height positions in the heat medium tank 72. Inside the heat storage tank 6, the high-temperature pipe 81 is connected to the upper part 72a of the heat medium tank 72, the medium-temperature pipe 82 is connected to the central part 72b of the heat medium tank 72, and the low-temperature pipe 83 is connected to the lower part 72c of the heat medium tank 72.

[0015] One end of the high-temperature pipe 81 is connected to the upper portion 72a of the heat medium tank 72, and the other end is connected to a pipe of the heat medium relay unit 3 (described later) (see FIG. 14 ). The high-temperature pipe 81 is connected to the hot water supply heat exchanger 74 and the first heat medium pump 31c1 midway along its length. The high-temperature pipe 81 is branched midway along its length by a first pipe 86 (described later), and is connected to the medium-temperature pipe 82 via the first pipe 86 and a first flow path switching valve 32a1 (described later). The high-temperature pipe 81 is also connected to the low-temperature pipe 83 via the first pipe 86, the first flow path switching valve 32a1, a second pipe 87, and a second flow path switching valve 32a2 (described later).

[0016] One end of the medium-temperature pipe 82 is connected to the center 72b of the heat medium tank 72, and the other end is connected to a pipe of the heat medium relay unit 3 (described later) (see FIG. 14 ). The medium-temperature pipe 82 is branched midway through by a first pipe 86 (described later), and is connected to the high-temperature pipe 81 via the first pipe 86 and a first flow path switching valve 32a1 (described later).

[0017] One end of the low-temperature pipe 83 is connected to the lower portion 72c of the heat medium tank 72, and the other end is connected to the pipe of the heat medium relay unit 3 (described later) (see FIG. 14 ). The low-temperature pipe 83 is also connected to a second flow path switching valve 32a2 and a second heat medium pump 31c2 in the middle of the pipe. The low-temperature pipe 83 is connected to the high-temperature pipe 81 via a first pipe 86, a first flow path switching valve 32a1, a second pipe 87, and a second flow path switching valve 32a2 (described later).

[0018] The heat storage tank 6 is equipped with a hot water heat exchanger 74 that is connected to a high-temperature pipe 81 and a water pipe 78 through which water flows, and that exchanges heat between a heat medium 91 flowing through the high-temperature pipe 81 and the water flowing through the water pipe 78. The hot water heat exchanger 74 is connected to the high-temperature pipe 81. In other words, the hot water heat exchanger 74 is provided in the high-temperature pipe 81. The hot water heat exchanger 74 is also connected to the water pipe 78. The hot water heat exchanger 74 exchanges heat between water flowing through the water pipe 78 that flows in from a water supply port 76 and the heat medium 91 that flows in from the high-temperature pipe 81, heating the water to a hot water supply temperature, and then flows out of the hot water supply port 77 to supply hot water via the water pipe 78. The water is, for example, city water. The hot water supply temperature is a temperature suitable for use by a user, for example, 40°C.

[0019] The heat storage tank 6 is equipped with a first heat medium pump 31c1 that causes the heat medium 91 to flow into the heat medium tank 72 and causes the heat medium 91 to flow out from the heat medium tank 72. The first heat medium pump 31c1 is connected to the high-temperature pipe 81. In other words, the first heat medium pump 31c1 is provided on the high-temperature pipe 81. The first heat medium pump 31c1 circulates the heat medium 91 stored inside the heat medium tank 72 within a circuit through which the heat medium 91 flows.

[0020] The heat storage tank 6 is equipped with a second heat medium pump 31c2 that causes the heat medium 91 to flow into the heat medium tank 72 and causes the heat medium 91 to flow out from the heat medium tank 72. The second heat medium pump 31c2 is connected to the low-temperature pipe 83. In other words, the second heat medium pump 31c2 is provided in the low-temperature pipe 83. The second heat medium pump 31c2 circulates the heat medium 91 stored inside the heat medium tank 72 within a circuit through which the heat medium 91 flows.

[0021] The first heat medium pump 31c1 and the second heat medium pump 31c2 are devices that are driven by, for example, a motor (not shown) and pump the heat medium 91 by pressure. The heat medium 91 is circulated through the piping by the first heat medium pump 31c1 and the second heat medium pump 31c2. Note that the heat storage tank 6 may have at least the first heat medium pump 31c1 and may not have the second heat medium pump 31c2. In this case, the heat medium 91 is circulated through the piping by the first heat medium pump 31c1, a first heat medium circulation pump 31a (described later), or a second heat medium circulation pump 31b (described later) (see FIG. 14 ).

[0022] The heat storage tank 6 includes a first pipe 86 that connects the high-temperature pipe 81 and the medium-temperature pipe 82 at a position on the high-temperature pipe 81 opposite the side where the heat medium tank 72 is located with respect to the hot water supply heat exchanger 74. One end of the first pipe 86 is connected to the high-temperature pipe 81, and the other end is connected to the medium-temperature pipe 82. A first flow path switching valve 32a1 is connected to the first pipe 86 midway through the pipeline. The heat storage tank 6 includes a second pipe 87 that connects the first pipe 86 and the low-temperature pipe 83. One end of the second pipe 87 is connected to the first pipe 86 via the first flow path switching valve 32a1, and the other end is connected to the low-temperature pipe 83 via the second flow path switching valve 32a2.

[0023] The heat storage tank 6 is connected to the first pipe 86 and the second pipe 87 and includes a first flow path switching valve 32a1 that switches the flow path through which the heat medium 91 flows. The heat storage tank 6 is also connected to the second pipe 87 and the low-temperature pipe 83 and includes a second flow path switching valve 32a2 that switches the flow path through which the heat medium 91 flows. The first flow path switching valve 32a1 and the second flow path switching valve 32a2 switch the flow direction of the heat medium 91 in the circuit through which the heat medium 91 flows.

[0024] The first flow path switching valve 32a1 and the second flow path switching valve 32a2 are, for example, three-way valves. The flow direction of the heat medium 91 is controlled by the first flow path switching valve 32a1 and the second flow path switching valve 32a2.

[0025] The first flow path switching valve 32a1 and the second flow path switching valve 32a2 switch, for example, between a circuit in which the heat medium 91 circulates between the upper part 72a and the central part 72b of the heat medium tank 72, and a circuit in which the heat medium 91 circulates between the upper part 72a and the lower part 72c.

[0026] The heat storage tank 6 uses the first flow path switching valve 32a1 and the second flow path switching valve 32a2 to switch the flow path of the heat medium 91 flowing inside the high-temperature pipe 81, the medium-temperature pipe 82, and the low-temperature pipe 83. The heat storage tank 6 switches between low-temperature heat storage operation, high-temperature heat storage operation, heat release operation, and simultaneous operation thereof, by switching the flow path of the heat medium 91 using the first flow path switching valve 32a1 and the second flow path switching valve 32a2. That is, the heat storage tank 6 switches between low-temperature heat storage operation, high-temperature heat storage operation, heat release operation, and simultaneous operation thereof, by switching the flow direction of the heat medium 91 using the first flow path switching valve 32a1 and the second flow path switching valve 32a2.

[0027] Fig. 2 is a circuit diagram showing the flow direction of the circulating medium during cold heat storage in the heat storage tank 6 according to the first embodiment. The arrows in Fig. 2 indicate the flow direction of the heat medium 91 during low-temperature heat storage operation. The heat medium 91 in the heat medium tank 72 flows out of the heat storage tank 6 through the medium-temperature piping 82 and is cooled by a cold heat source 101 of the heat-storage air-conditioning and hot water supply system 200 (described later) (see Fig. 14). The heat medium 91 cooled by the cold heat source 101 flows into the lower part 72c of the heat medium tank 72 through the low-temperature piping 83.

[0028] When performing cooling operation using thermal storage, the flow direction of the heat medium 91 is reversed, and the heat medium 91 flowing out of the low-temperature pipe 83 is supplied to the indoor unit 2b instead of the cold heat source 101 (see FIG. 14 ). Operation using thermal storage is referred to as heat dissipation operation. The thermal storage tank 6 and the thermal storage air conditioning and hot water supply system 200 perform cooling operation by supplying the low-temperature heat medium 91 from the thermal storage tank 6 to the indoor unit 2b and exchanging heat between the heat medium 91 and the indoor air using the use-side heat exchanger 30a.

[0029] Fig. 3 is a circuit diagram showing the flow direction of the circulating medium during hot heat storage in the heat storage tank 6 according to the first embodiment. The arrows in Fig. 3 indicate the flow direction of the heat medium 91 during high-temperature heat storage operation. The heat medium 91 flows out of the lower part 72c of the heat medium tank 72, passes through the low-temperature piping 83, and leaves the heat storage tank 6, where it is heated by the heat source 100 of the heat-storage air-conditioning and hot water supply system 200 (described later) (see Fig. 14). The heat medium 91 heated by the heat source 100 flows through the high-temperature piping 81 and into the upper part 72a of the heat medium tank 72. The heat medium 91 that passes through the inside of the heat medium tank 72 flows out of the lower part 72c of the heat medium tank 72.

[0030] When performing heating operation using thermal storage, the flow direction of the heat medium 91 is reversed, and the heat medium 91 flowing out of the high-temperature pipe 81 is supplied to the indoor unit 2a instead of the heat source 100 (see FIG. 14 ). As described above, operation using thermal storage is called heat dissipation operation. The thermal storage tank 6 and the thermal storage air conditioning and hot water supply system 200 perform heating operation by supplying high-temperature heat medium 91 from the thermal storage tank 6 to the indoor unit 2a and exchanging heat between the heat medium 91 and the indoor air using the use-side heat exchanger 30a.

[0031] Furthermore, in the thermal storage tank 6 and the thermal storage air conditioning and hot water supply system 200, the heat medium 91 flows in the same direction as in Figure 3 even during cold energy utilization hot heat storage operation. The heat medium 91 flowing out from the low-temperature piping 83 of the thermal storage tank 6 passes through the indoor unit 2a to cool the air, and after flowing out of the indoor unit 2a, is supplied to the heat source 100 (see Figure 14). The heat medium 91 heated by the heat source 100 flows through the high-temperature piping 81 into the upper part 72a of the heat medium tank 72.

[0032] Fig. 4 is a circuit diagram showing the flow direction of the circulating medium when storing hot heat in the heat storage tank 6 according to embodiment 1. The arrows in Fig. 4 indicate the flow direction of the heat medium 91. When storing hot heat, the heat storage tank 6 performs high-temperature heat storage operation as shown in Fig. 4. The heat medium 91 flowing out of the heat medium tank 72 passes through the medium-temperature piping 82 and is heated by the heat source 100 of the heat-storage air-conditioning and hot water supply system 200 (see Fig. 14).

[0033] The heated heat medium 91 flows through the high-temperature pipe 81 into the upper part 72a of the heat medium tank 72. The heat medium 91 that has passed through the inside of the heat medium tank 72 flows out from the medium-temperature pipe 82 in the center part 72b of the heat medium tank 72. This enables the heat storage tank 6 and the heat-storage air-conditioning and hot water supply system 200 to perform high-temperature heat storage operation while maintaining the lower part 72c of the heat medium tank 72 at a low temperature.

[0034] Fig. 5 is a circuit diagram showing the flow direction of the circulating medium during simultaneous cold and hot heat storage in the heat storage tank 6 according to embodiment 1. The arrows in Fig. 5 indicate the flow direction of the heat medium 91 during simultaneous cold and hot heat storage operation. The heat medium 91 flowing out of the heat medium tank 72 passes through the medium-temperature piping 82, and part of it is supplied to the heat source 100 of the heat-storage air-conditioning and hot water supply system 200, and the rest is supplied to the cold heat source 101 of the heat-storage air-conditioning and hot water supply system 200 (see Fig. 14).

[0035] A portion of the heat medium 91 is heated by the heat source 100 and then flows through the high-temperature pipe 81 into the upper portion 72a of the heat medium tank 72. Meanwhile, the remaining heat medium 91 is cooled by the cold heat source 101 and then flows through the low-temperature pipe 83 into the lower portion 72c of the heat medium tank 72. As described above, the heat storage tank 6 and the heat-storage air-conditioning and hot water supply system 200 are capable of simultaneous cold and hot heat storage operation, in which high-temperature heat is stored using a portion of the heat medium 91 inside the heat medium tank 72, and low-temperature heat is stored using the remaining heat medium 91.

[0036] On the other hand, the heat storage tank 6 and the heat storage air conditioning and hot water supply system 200 can perform simultaneous cooling and heating operations by using stored heat, by reversing the flow direction of the heat medium 91 in Fig. 5. The heat medium 91 flowing out of the heat medium tank 72 passes through the high-temperature pipe 81 and the low-temperature pipe 83 and is supplied to the indoor units 2a and 2b, rather than to the heat source 100 and the cold heat source 101.

[0037] The heat storage tank 6 and the heat storage air conditioning and hot water supply system 200 are capable of simultaneous heating and cooling operation by supplying the indoor units 2a and 2b with the low-temperature heat medium 91 flowing out from the low-temperature pipe 83 and the high-temperature heat medium 91 flowing out from the high-temperature pipe 81. The heat medium 91 that has exchanged heat in the user-side heat exchangers 30a of the indoor units 2a and 2b join together and flow from the medium-temperature pipe 82 into the center section 72b of the heat medium tank 72.

[0038] Fig. 6 is a circuit diagram showing the flow direction of the circulating medium during hot water supply operation of the heat storage tank 6 according to the first embodiment. The arrows in Fig. 6 indicate the flow direction of the heat medium 91 during hot water supply operation using stored heat. The heat medium 91 flowing out of the upper portion 72a of the heat medium tank 72 exchanges heat with water in the water pipe 78 by the hot water supply heat exchanger 74. The water flowing into the heat storage tank 6 from the water supply port 76 is heated to a hot water supply temperature by the hot water supply heat exchanger 74 and then flows out from the hot water supply port 77.

[0039] When the water temperature is high (for example, 30°C), such as in summer, the heat medium 91 that has exchanged heat with the water and been cooled in the hot water supply heat exchanger 74 is at a medium temperature of, for example, 40°C, and therefore flows through the first pipe 86, the medium temperature pipe 82, and into the central portion 72b of the heat medium tank 72. Here, the flow path of the heat medium 91 is switched by the first flow path switching valve 32a1, and the heat medium 91 circulates through the high temperature pipe 81, the first pipe 86, the medium temperature pipe 82, and the heat medium tank 72.

[0040] On the other hand, when the water temperature is low (for example, 10°C), such as in winter, the temperature of the heat medium 91 cooled by the hot water heat exchanger 74 drops. After the temperature drops, the heat medium 91 preferably flows into the lower portion 72c of the heat medium tank 72 rather than the central portion 72b, and stores heat in the lower portion 72c of the heat medium tank 72. This is because the heat medium 91 stored inside the heat medium tank 72 has a temperature distribution that varies depending on the vertical height. Here, the flow path of the heat medium 91 is switched by the first flow path switching valve 32a1 and the second flow path switching valve 32a2, and the heat medium 91 circulates through the high-temperature pipe 81, the first pipe 86, the second pipe 87, the low-temperature pipe 83, and the heat medium tank 72.

[0041] [Effects of Heat Storage Tank 6] The heat storage tank 6 includes a heat medium tank 72 that stores a heat medium 91, a high-temperature pipe 81 connected to an upper portion 72a of the heat medium tank 72, and a low-temperature pipe 83 connected to a lower portion 72c of the heat medium tank 72. The heat storage tank 6 also includes a medium-temperature pipe 82 that is connected to the heat medium tank 72 between the high-temperature pipe 81 and the low-temperature pipe 83 in the vertical direction of the heat medium tank 72.

[0042] The heat storage tank 6 is also connected to the high-temperature pipe 81 and includes a first heat medium pump 31c1 that causes the heat medium 91 to flow into the heat medium tank 72 and causes the heat medium 91 to flow out from the heat medium tank 72. The heat storage tank 6 is also connected to the low-temperature pipe 83 and includes a second heat medium pump 31c2 that causes the heat medium 91 to flow into the heat medium tank 72 and causes the heat medium 91 to flow out from the heat medium tank 72. The heat storage tank 6 is also equipped with a first pipe 86 that connects the high-temperature pipe 81 and the medium-temperature pipe 82, and a second pipe 87 that connects the first pipe 86 and the low-temperature pipe 83.

[0043] The heat storage tank 6 is also connected to the first pipe 86 and the second pipe 87 and includes a first flow path switching valve 32a1 that switches the flow path through which the heat medium 91 flows. The heat storage tank 6 is also connected to the second pipe 87 and the low-temperature pipe 83 and includes a second flow path switching valve 32a2 that switches the flow path through which the heat medium 91 flows.

[0044] The heat storage tank 6 uses the first flow path switching valve 32a1 and the second flow path switching valve 32a2 to switch the flow path of the heat medium 91 flowing inside the high-temperature pipe 81, the medium-temperature pipe 82, and the low-temperature pipe 83. The heat storage tank 6 switches between low-temperature heat storage operation, high-temperature heat storage operation, heat release operation, and simultaneous operation of each of these, by switching the flow path of the heat medium 91 flowing inside the high-temperature pipe 81, the medium-temperature pipe 82, and the low-temperature pipe 83.

[0045] Conventionally, a heat storage tank requires two pipes for the forward and return of the heat medium to store and release low-temperature and high-temperature heat, i.e., a total of four pipes. The heat storage tank 6 according to the first embodiment uses a high-temperature pipe 81, a medium-temperature pipe 82, and a low-temperature pipe 83, thereby integrating the flow path of the medium-temperature heat medium 91 after heat storage and release into a single path, thereby reducing the number of pipes. In the heat storage air-conditioning and hot water supply system 200, the heat storage tank 6, the heat source unit 1a, and the heat medium converter 3 are often installed separately. Reducing the number of connecting pipes simplifies the installation of the heat storage tank 6 and the heat storage air-conditioning and hot water supply system 200, facilitating installation. Furthermore, the heat storage tank 6, with its above-described configuration, can form a temperature distribution within a single heat medium tank 72 and store both high and low temperatures. Therefore, reducing the number of tanks for heat storage reduces the number of components.

[0046] The heat storage tank 6 is also equipped with a hot water heat exchanger 74 that is connected to the high-temperature pipe 81 and the water pipe 78 through which water flows, and that exchanges heat between the heat medium 91 flowing in the high-temperature pipe 81 and the water flowing in the water pipe 78. Because the heat storage tank 6 and the heat storage air conditioning and hot water supply system 200 are equipped with the hot water heat exchanger 74, hot water supply operation can be performed using the hot water heat exchanger 74. Therefore, the heat storage tank 6 and the heat storage air conditioning and hot water supply system 200 can perform hot water supply operation while performing cooling operation or heating operation using the outdoor unit 1 and the heat medium converter 3 at the same time.

[0047] Second Embodiment Fig. 7 is a schematic diagram showing a heat storage tank 6 according to a second embodiment. Note that parts having the same configuration as those in the heat storage tank 6 of Figs. 1 to 6 are given the same reference numerals, and their description will be omitted. The heat storage tank 6 according to the second embodiment differs from the heat storage tank 6 according to the first embodiment in that it has a high-temperature heat storage tank 71 and a low-temperature heat storage tank 73. The following description will focus on the configuration of the heat storage tank 6 according to the second embodiment that differs from the heat storage tank 6 according to the first embodiment, and the configuration not described in the second embodiment is the same as that according to the first embodiment.

[0048] The heat storage tank 6 includes a high-temperature heat storage tank 71 connected in the high-temperature piping 81 between the hot water supply heat exchanger 74 and the heat medium tank 72, and a low-temperature heat storage tank 73 connected in the low-temperature piping 83 between the second flow path switching valve 32a2 and the heat medium tank 72. The high-temperature heat storage tank 71 is connected in the high-temperature piping 81 between the connection portion of the first piping 86 and the heat medium tank 72.

[0049] The high-temperature heat storage tank 71 contains therein a high-temperature heat storage material 90a that exchanges heat with the heat medium 91 and has a larger heat storage capacity per unit volume than the heat medium 91, and a high-temperature heat storage heat exchanger 75a through which the heat medium 91 circulates and exchanges heat with the high-temperature heat storage material 90a. The low-temperature heat storage tank 73 contains therein a low-temperature heat storage material 90b that exchanges heat with the heat medium 91 and has a larger heat storage capacity per unit volume than the heat medium 91, and a low-temperature heat storage heat exchanger 75b through which the heat medium 91 circulates and exchanges heat with the low-temperature heat storage material 90b. The heat storage tank 6 has the high-temperature heat storage tank 71, the heat medium tank 72, and the low-temperature heat storage tank 73 connected in series via piping.

[0050] The high-temperature heat storage tank 71 and the low-temperature heat storage tank 73 are filled with a latent heat storage material 90, and contain a heat storage heat exchanger 75 that exchanges heat between the latent heat storage material 90 and a heat medium 91. The latent heat storage material 90 is a high-temperature heat storage material 90a and a low-temperature heat storage material 90b. The heat storage heat exchangers 75 are a high-temperature heat storage heat exchanger 75a and a low-temperature heat storage heat exchanger 75b. The high-temperature heat storage tank 71 is filled with a high-temperature heat storage material 90a, and contains a high-temperature heat storage heat exchanger 75a that exchanges heat between the high-temperature heat storage material 90a and the heat medium 91. The low-temperature heat storage tank 73 is filled with a low-temperature heat storage material 90b, and contains a low-temperature heat storage heat exchanger 75b that exchanges heat between the low-temperature heat storage material 90b and the heat medium 91.

[0051] 7, a high-temperature heat storage tank 71, a heat medium tank 72, and a low-temperature heat storage tank 73 are connected in series in this order inside the heat storage tank 6. Normally, inside the heat medium tank 72, high-temperature fluid rises and low-temperature fluid tends to descend due to natural convection, so by arranging the high-temperature heat storage tank 71 above the heat medium tank 72 and the low-temperature heat storage tank 73 below the heat medium tank 72, it becomes easy to keep the high-temperature heat storage tank 71 at a high temperature and the low-temperature heat storage tank 73 at a low temperature.

[0052] As an example, the heat medium 91 that has exchanged heat with the low-temperature heat storage material 90b in the low-temperature heat storage tank 73 flows out from the low-temperature piping 83 connected to the upper part of the low-temperature heat storage tank 73 and flows into the lower part 72c (see FIG. 1) of the heat medium tank 72. Then, the heat medium 91 that has flowed out from the high-temperature piping 81 connected to the upper part 72a (see FIG. 1) of the heat medium tank 72 flows into the high-temperature heat storage tank 71 and exchanges heat with the high-temperature heat storage material 90a by the high-temperature heat storage heat exchanger 75a.

[0053] The high-temperature heat storage tank 71 can store heat in a high-temperature heat storage material 90a that has exchanged heat with a heat medium 91 in a high-temperature heat storage heat exchanger 75a. For the high-temperature heat storage material 90a, which is the latent heat storage material 90 in the high-temperature heat storage tank 71, a material having a melting point at a temperature (for example, 40 to 80°C) higher than the hot water supply temperature can be used, and for example, paraffin or sodium acetate trihydrate can be used.

[0054] The low-temperature heat storage tank 73 can store heat in a low-temperature heat storage material 90b that has exchanged heat with a heat medium 91 in a low-temperature heat storage heat exchanger 75b. For the low-temperature heat storage material 90b, which is the latent heat storage material 90 in the low-temperature heat storage tank 73, a material having a melting point between 0°C and 20°C can be used, for example, such as ice, a TBAB aqueous solution, or pentadecane.

[0055] The heat storage tank 6 has a high-temperature pipe 81 connected to the high-temperature heat storage tank 71, a low-temperature pipe 83 connected to the low-temperature heat storage tank 73, and a heat medium tank 72 connected to the high-temperature pipe 81, the medium-temperature pipe 82, and the low-temperature pipe 83.

[0056] The high-temperature pipe 81 is connected to the hot water supply heat exchanger 74, the first heat medium pump 31c1, and the high-temperature heat storage tank 71. The low-temperature pipe 83 is connected to the second flow path switching valve 32a2, the second heat medium pump 31c2, and the low-temperature heat storage tank 73. As described above, the heat storage tank 6 may have at least the first heat medium pump 31c1 and may not have the second heat medium pump 31c2. In this case, the heat medium 91 is circulated through the pipe by the first heat medium pump 31c1, a first heat medium circulation pump 31a (described later), or a second heat medium circulation pump 31b (described later) (see FIG. 15 ).

[0057] Fig. 8 is a circuit diagram showing the flow direction of the circulating medium during cold heat storage in the heat storage tank 6 according to embodiment 2. The arrows in Fig. 8 indicate the flow direction of the heat medium 91 during low-temperature heat storage operation. The heat medium 91 in the heat medium tank 72 flows out of the medium-temperature pipe 82 and is cooled by the cold heat source 101 of the heat-storage air-conditioning and hot water supply system 200 (described later) (see Fig. 15).

[0058] The heat medium 91 cooled by the cold heat source 101 flows through the low-temperature piping 83 into the low-temperature heat storage tank 73. The heat medium 91 that has flowed into the low-temperature heat storage tank 73 passes through the low-temperature heat storage heat exchanger 75b, cools the low-temperature heat storage material 90b, and then flows into the lower part 72c of the heat medium tank 72 (see FIG. 1).

[0059] When performing cooling operation using the thermal storage, the flow direction of the heat medium 91 is reversed, and the heat medium 91 flowing out of the low-temperature pipe 83 is supplied to the indoor unit 2b instead of the cold heat source 101 (see FIG. 15 ). The thermal storage tank 6 and the thermal storage air conditioning and hot water supply system 200 perform cooling operation by supplying the low-temperature heat medium 91 from the thermal storage tank 6 to the indoor unit 2b and exchanging heat between the heat medium 91 and the indoor air by the use-side heat exchanger 30a.

[0060] Fig. 9 is a circuit diagram showing the flow direction of the circulating medium during hot heat storage in the heat storage tank 6 according to embodiment 2. The arrows in Fig. 9 indicate the flow direction of the heat medium 91 during high-temperature heat storage operation. The heat medium 91 flows out of the lower part 72c of the heat medium tank 72 (see Fig. 1), passes through the low-temperature heat storage tank 73, and then flows out of the low-temperature heat storage tank 73, passes through the low-temperature piping 83, and flows out of the heat storage tank 6, and is heated by the heat source 100 of the heat-storage air-conditioning and hot water supply system 200 (described later) (see Fig. 15).

[0061] The heat medium 91 heated by the heat source 100 flows through the high-temperature pipe 81 into the high-temperature heat storage tank 71. The heat medium 91 that has flowed into the high-temperature heat storage tank 71 passes through the high-temperature heat storage heat exchanger 75a in the high-temperature heat storage tank 71, heats the high-temperature heat storage material 90a, and then flows into the upper part 72a (see FIG. 1 ) of the heat medium tank 72. The heat medium 91 that has passed through the inside of the heat medium tank 72 flows out from the lower part 72c of the heat medium tank 72 and flows into the low-temperature heat storage tank 73.

[0062] When performing heating operation using the stored heat, the flow direction of the heat medium 91 is reversed, and the heat medium 91 flowing out of the high-temperature pipe 81 is supplied to the indoor unit 2a instead of the heat source 100 (see FIG. 15 ). The heat storage tank 6 and the heat storage air conditioning and hot water supply system 200 perform heating operation by supplying high-temperature heat medium 91 from the heat storage tank 6 to the indoor unit 2a and exchanging heat between the heat medium 91 and the indoor air by the use-side heat exchanger 30a.

[0063] Furthermore, in the heat storage tank 6 and the heat storage air conditioning and hot water supply system 200, the heat medium 91 flows in the same direction as in Fig. 9 even during cold energy utilization hot heat storage operation. The heat medium 91 flowing out from the low-temperature piping 83 of the heat storage tank 6 passes through the indoor unit 2a to cool the air, and after flowing out of the indoor unit 2a, is supplied to the heat source 100 (see Fig. 15). The heat medium 91 heated by the heat source 100 flows through the high-temperature piping 81 into the high-temperature heat storage tank 71, and then flows into the upper part 72a of the heat medium tank 72 (see Fig. 1).

[0064] Fig. 10 is a circuit diagram showing the flow direction of the circulating medium when storing hot heat in the heat storage tank 6 according to embodiment 2. The arrows in Fig. 10 indicate the flow direction of the heat medium 91. When storing hot heat, the heat storage tank 6 performs the high-temperature heat storage operation shown in Fig. 10. The heat medium 91 flowing out of the heat medium tank 72 passes through the medium-temperature piping 82 and is heated by the heat source 100 of the heat-storage air-conditioning and hot water supply system 200 (see Fig. 15).

[0065] The heated heat medium 91 flows into the high-temperature heat storage tank 71 through the high-temperature piping 81. The heat medium 91 that flows into the high-temperature heat storage tank 71 passes through the high-temperature heat storage heat exchanger 75a in the high-temperature heat storage tank 71, heats the high-temperature heat storage material 90a, and then flows into the upper part 72a of the heat medium tank 72. The heat medium 91 that passes through the inside of the heat medium tank 72 flows out from the medium-temperature piping 82 in the center part 72b of the heat medium tank 72. As a result, the heat storage tank 6 and the heat-storage air-conditioning and hot water supply system 200 are able to perform high-temperature heat storage operation while maintaining the inside of the low-temperature heat storage tank 73 at a low temperature, because the heat medium 91 does not pass through the inside of the low-temperature heat storage tank 73 and heat exchange between the heat medium 91 and the low-temperature heat storage material 90b does not occur.

[0066] Fig. 11 is a circuit diagram showing the flow direction of the circulating medium during simultaneous cold and hot heat storage in the heat storage tank 6 according to embodiment 2. The arrows in Fig. 11 indicate the flow direction of the heat medium 91 during simultaneous cold and hot heat storage operation. The heat medium 91 flowing out of the heat medium tank 72 passes through the medium-temperature piping 82, and part of it is supplied to the heat source 100 of the heat-storage air-conditioning and hot water supply system 200, and the rest is supplied to the cold heat source 101 of the heat-storage air-conditioning and hot water supply system 200 (see Fig. 15).

[0067] A portion of the heat medium 91 is heated by the heat source 100, and then flows through the high-temperature pipe 81 into the high-temperature heat storage tank 71. The heat medium 91 that has flowed into the high-temperature heat storage tank 71 passes through the high-temperature heat storage heat exchanger 75a in the high-temperature heat storage tank 71, heats the high-temperature heat storage material 90a, and then flows into the upper portion 72a of the heat medium tank 72 (see FIG. 1 ).

[0068] Meanwhile, the remaining heat medium 91 is cooled by the cold heat source 101, and then flows into the low-temperature heat storage tank 73 through the low-temperature piping 83. The heat medium 91 that has flowed into the low-temperature heat storage tank 73 passes through the low-temperature heat storage heat exchanger 75b in the low-temperature heat storage tank 73 to cool the low-temperature heat storage material 90b, and then flows into the lower part 72c of the heat medium tank 72 (see FIG. 1 ). As described above, the heat storage tank 6 and the heat-storage air-conditioning and hot water supply system 200 are capable of simultaneous cold and hot heat storage operation, in which high-temperature heat is stored using part of the heat medium 91 inside the heat medium tank 72, and low-temperature heat is stored using the remaining heat medium 91.

[0069] On the other hand, the heat storage tank 6 and the heat storage air conditioning and hot water supply system 200 can perform simultaneous cooling and heating operation by using stored heat, by reversing the flow direction of the heat medium 91 in Fig. 11. The heat medium 91 flowing out of the heat medium tank 72 passes through the high-temperature pipe 81 and the low-temperature pipe 83 and is supplied to the indoor units 2a and 2b, rather than to the heat source 100 and the cold heat source 101.

[0070] The heat storage tank 6 and the heat storage air conditioning and hot water supply system 200 are capable of simultaneous heating and cooling operation by supplying the indoor units 2a and 2b with the low-temperature heat medium 91 flowing out from the low-temperature pipe 83 and the high-temperature heat medium 91 flowing out from the high-temperature pipe 81. The heat medium 91 that has exchanged heat in the user-side heat exchangers 30a of the indoor units 2a and 2b join together and flow from the medium-temperature pipe 82 into the center section 72b of the heat medium tank 72.

[0071] Fig. 12 is a circuit diagram showing the flow direction of the circulating medium during hot water supply operation of the heat storage tank 6 according to the second embodiment. The arrows in Fig. 12 indicate the flow direction of the heat medium 91 and water during hot water supply operation using heat storage. The heat medium 91 flows out of the upper portion 72a of the heat medium tank 72, passes through the high-temperature heat storage tank 71, and then flows out of the high-temperature heat storage tank 71, where it exchanges heat with water in the water pipe 78 by the hot water supply heat exchanger 74. The water that flows into the heat storage tank 6 from the water supply port 76 is heated to a hot water supply temperature by the hot water supply heat exchanger 74, and then flows out of the hot water supply port 77.

[0072] When the water temperature is high (for example, 30°C), such as in summer, the heat medium 91 that has exchanged heat with the water and been cooled in the hot water supply heat exchanger 74 is at a medium temperature of, for example, 40°C, and therefore flows through the first pipe 86, the medium temperature pipe 82, and into the central portion 72b of the heat medium tank 72. Here, the flow path of the heat medium 91 is switched by the first flow path switching valve 32a1, and the heat medium 91 circulates through the high temperature pipe 81, the first pipe 86, the medium temperature pipe 82, and the heat medium tank 72.

[0073] On the other hand, when the water temperature is low (for example, 10°C), such as in winter, the temperature of the heat medium 91 cooled by the hot water heat exchanger 74 drops. After the temperature drops, the heat medium 91 preferably flows into the lower portion 72c of the heat medium tank 72, rather than into the central portion 72b, and stores heat in the lower portion 72c of the heat medium tank 72. This is because the heat medium 91 stored inside the heat medium tank 72 has a temperature distribution that varies depending on the vertical height. Here, the flow path of the heat medium 91 is switched by the first flow path switching valve 32a1 and the second flow path switching valve 32a2, and the heat medium 91 circulates through the high-temperature pipe 81, the first pipe 86, the second pipe 87, the low-temperature pipe 83, the low-temperature heat storage tank 73, and the heat medium tank 72.

[0074] [Function and Effect of Heat Storage Tank 6] The heat storage tank 6 includes a high-temperature heat storage tank 71 connected in the high-temperature piping 81 between the connection portion of the first piping 86 and the heat medium tank 72, and a low-temperature heat storage tank 73 connected in the low-temperature piping 83 between the second flow path switching valve 32a2 and the heat medium tank 72. The high-temperature heat storage tank 71 includes therein a high-temperature heat storage material 90a that exchanges heat with the heat medium 91 and has a larger heat storage amount per unit volume than the heat medium 91, and a high-temperature heat storage heat exchanger 75a through which the heat medium 91 circulates and exchanges heat with the high-temperature heat storage material 90a. The low-temperature heat storage tank 73 includes therein a low-temperature heat storage material 90b that exchanges heat with the heat medium 91 and has a larger heat storage amount per unit volume than the heat medium 91, and a low-temperature heat storage heat exchanger 75b through which the heat medium 91 circulates and exchanges heat with the low-temperature heat storage material 90b. The heat storage tank 6 has a high-temperature heat storage tank 71, a heat medium tank 72, and a low-temperature heat storage tank 73 connected in series. The heat storage tank 6 of the second embodiment uses heat storage materials such as a high-temperature heat storage material 90a and a low-temperature heat storage material 90b that have a larger heat storage capacity per unit volume than the heat medium 91, thereby making it possible to reduce the size of the heat medium tank 72 and the heat storage tank 6. Furthermore, the heat storage tank 6 of the second embodiment has the same structure as the heat storage tank 6 of the first embodiment, and therefore can achieve the same effects as the heat storage tank 6 of the first embodiment.

[0075] Embodiment 3. Figure 13 is a schematic diagram showing a heat storage tank 6 according to embodiment 3. Note that parts having the same configuration as those in the heat storage tank 6 of Figures 1 to 12 are given the same reference numerals, and their description will be omitted. The heat storage tank 6 according to embodiment 3 differs from the heat storage tank 6 according to embodiments 1 and 2 in the configuration of the medium-temperature piping 82. The following description will focus on the configuration of the heat storage tank 6 according to embodiment 3 that differs from the heat storage tank 6 according to embodiments 1 and 2, and the configuration not described in embodiment 3 is the same as in embodiments 1 and 2.

[0076] The medium-temperature pipe 82 of the heat storage tank 6 according to the third embodiment branches into at least two pipes and connects to the heat medium tank 72. The medium-temperature pipe 82 has a medium-temperature pipe switching valve 84a at the branched portion. The heat storage tank 6 and the heat-storage air-conditioning and hot water supply system 200 can adjust the amount of low-temperature heat storage and the amount of high-temperature heat storage by changing the volume of the flow path of the heat medium 91 during heat storage operation using the medium-temperature pipe switching valve 84a according to the amount of heat storage at the required temperature.

[0077] The medium temperature pipe 82 is connected to two different locations in the heat medium tank 72 by a medium temperature pipe switching valve 84a. The medium temperature pipe switching valve 84a is, for example, a three-way valve. Note that the medium temperature pipe switching valve 84a is not limited to a three-way valve, and the configuration of the switching valve is determined by the number of branches of the medium temperature pipe 82.

[0078] For example, in the summer when cold energy usage is high, the thermal storage air conditioning and hot water supply system 200 uses the medium temperature pipe switching valve 84a to cause the heat medium 91 to flow out from the upper side of the heat medium tank 72 during cold energy storage, thereby allowing most of the heat medium 91 in the heat medium tank 72 to be used for cold energy storage. On the other hand, in the intermediate seasons when cold energy usage is low, the thermal storage air conditioning and hot water supply system 200 uses the medium temperature pipe switching valve 84a to cause the heat medium 91 to flow out from the lower side of the heat medium tank 72 and performs cold energy storage, allowing most of the heat medium 91 in the upper side of the heat medium tank 72 to be used for hot energy storage.

[0079] [Effects of the Heat Storage Tank 6] The medium-temperature pipe 82 of the heat storage tank 6 branches into at least two pipes connected to the heat medium tank 72, and the branched portion has a medium-temperature pipe switching valve 84a. The heat storage tank 6 adjusts the amount of low-temperature heat storage and the amount of high-temperature heat storage by changing the volume of the heat medium 91 flow path during heat storage operation using the medium-temperature pipe switching valve 84a according to the amount of heat storage at the required temperature. This configuration of the medium-temperature pipe 82 in the heat storage tank 6 allows the temperature distribution of the heat medium 91 to be adjusted to a high or low temperature when the required temperature range for heat storage differs, such as in winter or summer. This allows the heat medium tank 72 to be made smaller, and therefore the heat storage tank 6 can be made smaller. In other words, the medium-temperature pipe 82 with the medium-temperature pipe switching valve 84a allows the heat storage amounts of cold and hot heat to be adjusted according to the utilization rates, thereby making effective use of the space in the heat storage tank 6 and making the entire system more compact. Furthermore, the heat storage tank 6 of the third embodiment has the same structure as the heat storage tank 6 of the first and second embodiments, and therefore can achieve the same effects as the heat storage tank 6 of the first and second embodiments.

[0080] Embodiment 4. Figure 14 is a schematic diagram of a first example of a heat storage air conditioning and hot water supply system 200 according to embodiment 4. Figure 15 is a schematic diagram of a second example of a heat storage air conditioning and hot water supply system 200 according to embodiment 4. The heat storage air conditioning and hot water supply system 200 of the first example shown in Figure 14 is a heat storage air conditioning and hot water supply system 200 equipped with the heat storage tank 6 of embodiment 1. The heat storage air conditioning and hot water supply system 200 of the second example shown in Figure 15 is a heat storage air conditioning and hot water supply system 200 equipped with the heat storage tank 6 of embodiment 2. Note that the heat storage air conditioning and hot water supply system 200 according to embodiment 4 may be equipped with the heat storage tank 6 according to embodiment 3.

[0081] In the description of the heat storage air conditioning and hot water supply system 200, parts having the same configuration as the heat storage tank 6 in Figures 1 to 13 are denoted by the same reference numerals, and their description will be omitted. Below, the heat storage air conditioning and hot water supply system 200 of embodiment 4 will be described, and the configuration not described in embodiment 4 is the same as in embodiments 1 to 3.

[0082] The heat storage air conditioning and hot water supply system 200 includes a heat storage tank 6, a plurality of indoor units 2, a heat medium circulation circuit 10b, a heating intermediate heat medium heat exchanger 14a, a cooling intermediate heat medium heat exchanger 14b, a first heat medium circulation pump 31a, and a second heat medium circulation pump 31b. The heat storage air conditioning and hot water supply system 200 also includes a plurality of heat medium flow path switching valves 32a, a plurality of heat medium flow rate control devices 34a, and a plurality of heat medium temperature detection sensors 35a.

[0083] The heat storage air conditioning and hot water supply system 200 controls the heat medium flow switching valves 32a and the heat medium flow control devices 34a based on detection information from the heat medium temperature detection sensors 35a. The heat storage air conditioning and hot water supply system 200 selects cooling, heating, cold heat storage, hot heat storage, hot water supply, or a combination thereof by controlling the heat medium flow switching valves 32a and the heat medium flow control devices 34a.

[0084] More specifically, the heat storage air conditioning and hot water supply system 200 includes an outdoor unit 1 which is a heat source unit 1a, a heat medium converter 3 which heats and cools a heat medium 91 and switches the flow path of the heat medium 91, and at least one indoor unit 2 which supplies conditioned air. The heat storage air conditioning and hot water supply system 200 further includes a heat storage tank 6 which stores the heat of the heat medium 91 and exchanges heat between the heat medium 91 and water flowing through a water pipe 78.

[0085] The outdoor unit 1 serves as a heat source for the thermal storage air conditioning and hot water supply system 200. The outdoor unit 1 includes a compressor 10, a refrigerant flow switching device 11, an air heat exchanger 12, and an accumulator 16. The outdoor unit 1 also includes an outdoor air temperature detection sensor 37.

[0086] The compressor 10 is provided in a refrigerant circulation circuit 10a (described later) and compresses and discharges the drawn refrigerant. The compressor 10 draws in low-temperature, low-pressure refrigerant, compresses the drawn refrigerant, and discharges high-temperature, high-pressure refrigerant. The refrigerant flow switching device 11 switches the flow direction of the refrigerant in the refrigerant circulation circuit 10a. The refrigerant flow switching device 11 is, for example, a four-way valve. The refrigerant flow switching device 11 switches the valve corresponding to the cooling / heating operation mode based on instructions from a control device 50 (described later) and switches the refrigerant circulation circuit.

[0087] The air heat exchanger 12 is provided in the refrigerant circulation circuit 10a and performs heat exchange between the air and the refrigerant. More specifically, the air heat exchanger 12 performs heat exchange between the air surrounding the air heat exchanger 12 and the refrigerant flowing inside the air heat exchanger 12.

[0088] The air heat exchanger 12 functions as an evaporator or a condenser depending on the switching of the refrigerant circulation circuit 10a by the refrigerant flow switching device 11. The accumulator 16 has a refrigerant storage function for storing excess refrigerant and a gas-liquid separation function for storing liquid refrigerant that is temporarily generated when the operating state changes. The outside air temperature detection sensor 37 detects the outside air temperature.

[0089] The heat medium relay unit 3 includes a heating intermediate heat exchanger 14a, a cooling intermediate heat exchanger 14b, a first expansion device 15a, a second expansion device 15b, a first heat medium circulation pump 31a, and a second heat medium circulation pump 31b. The heat medium relay unit 3 also includes a plurality of heat medium flow switching valves 32a, a plurality of heat medium flow control devices 34a, and a plurality of heat medium temperature detection sensors 35a.

[0090] The heating intermediate heat exchanger 14a and the cooling intermediate heat exchanger 14b are provided in the refrigerant circulation circuit 10a and the heat medium circulation circuit 10b, and perform heat exchange between the refrigerant flowing in the refrigerant circulation circuit 10a and the heat medium 91 flowing in the heat medium circulation circuit 10b. The heating intermediate heat exchanger 14a and the cooling intermediate heat exchanger 14b perform heat exchange between the refrigerant flowing in the refrigerant circulation circuit 10a and the heat medium 91 flowing in the heat medium circulation circuit 10b, thereby heating or cooling the heat medium 91.

[0091] The heating intermediate heat exchanger 14a exchanges heat between the heat source fluid of the heat source unit 1a and the heat medium 91 circulating in the heat medium circuit 10b to heat the heat medium 91. The cooling intermediate heat exchanger 14b exchanges heat between the heat source fluid of the heat source unit 1a and the heat medium 91 circulating in the heat medium circuit 10b to cool the heat medium 91.

[0092] The heat medium 91 is heated by the heating intermediate heat exchanger 14a and cooled by the cooling intermediate heat exchanger 14b in the heat medium relay unit 3. The heating intermediate heat exchanger 14a and the cooling intermediate heat exchanger 14b function as a condenser or an evaporator.

[0093] In the heat storage air conditioning and hot water supply system 200, the heating intermediate heat exchanger 14a serves as the heat source 100, and heats the heat medium 91 to store hot heat in the heat storage tank 6. In the heat storage air conditioning and hot water supply system 200, the cooling intermediate heat exchanger 14b serves as the cold heat source 101, and cools the heat medium 91 to store cold heat in the heat storage tank 6.

[0094] The first expansion device 15a and the second expansion device 15b are provided in the refrigerant circuit 10a and are pressure reducing devices that reduce the pressure of the refrigerant flowing through the refrigerant circuit 10a. The first expansion device 15a and the second expansion device 15b are, for example, electronic expansion valves that can adjust the aperture of their throttling, and by adjusting the aperture, the pressure of the refrigerant flowing into the air heat exchanger 12, the heating intermediate heat exchanger 14a, or the cooling intermediate heat exchanger 14b is controlled.

[0095] The first heat medium circulation pump 31a and the second heat medium circulation pump 31b are devices that are driven by, for example, a motor (not shown) and use pressure to send the heat medium 91. The first heat medium circulation pump 31a and the second heat medium circulation pump 31b change the flow rate (discharge flow rate) of the heat medium 91 by changing the rotation speed of the built-in motor (not shown) within a certain range.

[0096] The first heat medium circulation pump 31a is provided in the heat medium circulation circuit 10b corresponding to the heating intermediate heat exchanger 14a. The second heat medium circulation pump 31b is provided in the heat medium circulation circuit 10b corresponding to the cooling intermediate heat exchanger 14b.

[0097] The heat medium 91 is circulated through the thermal storage air-conditioning and hot water supply system 200 by the first heat medium circulation pump 31a and the second heat medium circulation pump 31b in the heat medium relay unit 3. The heat medium 91 is circulated through the piping that constitutes the heat medium circulation circuit 10b by the first heat medium circulation pump 31a and the second heat medium circulation pump 31b.

[0098] The plurality of heat medium flow switching valves 32a are provided in the heat medium circulation circuit 10b that connects the indoor units 2 and the heat storage tank 6 with the heating intermediate heat exchanger 14a and the cooling intermediate heat exchanger 14b. The plurality of heat medium flow switching valves 32a switch the connection destinations of the indoor units 2 and the heat storage tank 6 with respect to the heating intermediate heat exchanger 14a and the cooling intermediate heat exchanger 14b in the heat medium circulation circuit 10b.

[0099] The plurality of heat medium flow switching valves 32a are, for example, three-way valves. The flow direction of the heat medium 91 is controlled by the plurality of heat medium flow switching valves 32a. In the heat storage air conditioning and hot water supply system 200, the plurality of heat medium flow switching valves 32a switch the flow direction of the heat medium 91 by controlling the valves, and also switch the flow path through which the heat medium 91 flows. In the heat storage air conditioning and hot water supply system 200, the plurality of connection heat medium pipes 5 connected to the indoor units 2 are each provided with a heat medium flow switching valve 32a, and the flow of the heat medium 91 is changed by switching between heating and cooling, for example, by switching the flow path using the heat medium flow switching valve 32a.

[0100] The plurality of heat medium flow switching valves 32a, e.g., three-way valves, are each connected to the heat medium inlet ports of the use-side heat exchangers 30a through pipes, and switch the flow paths at the inlet side (heat medium inlet side) of the use-side heat exchangers 30a. The plurality of heat medium flow switching valves 32a, e.g., three-way valves, are each connected to the heat medium outlet side of the use-side heat exchangers 30a through pipes, and switch the flow paths at the outlet side (heat medium outlet side) of the use-side heat exchangers 30a. These heat medium flow switching valves 32a switch the heat medium circulation circuit 10b to circulate either the heat medium 91 heated or cooled in the cooling intermediate heat exchanger 14b or the heating intermediate heat exchanger 14a to the use-side heat exchanger 30a.

[0101] The plurality of heat medium flow control devices 34a are provided in the heat medium circulation circuit 10b that connects the indoor unit 2 and the heat storage tank 6 to the heating-intermediate heat exchanger 14a and the cooling-intermediate heat exchanger 14b, and control the flow rate of the heat medium 91 flowing through the heat medium circulation circuit 10b.

[0102] The heat medium flow control devices 34a are, for example, two-way valves. The heat medium flow control devices 34a adjust the flow rate of the heat medium 91 flowing through the heat medium circulation circuit 10b in the heat storage air conditioning hot water supply system 200. The heat medium flow control devices 34a are connected to the connection heat medium pipes 5 connected to the use-side heat exchanger 30a (described later) and the connection heat medium pipes 5 connected to the high-temperature pipe 81 and the low-temperature pipe 83 of the heat storage tank 6.

[0103] For example, each of the plurality of heat medium flow control devices 34a, which are two-way valves, adjusts the flow rate of the heat medium 91 flowing into the use-side heat exchanger 30a. Also, the plurality of heat medium flow control devices 34a adjusts the flow rate of the heat medium 91 flowing into the heat storage tank 6.

[0104] The plurality of heat medium temperature detection sensors 35a detect the temperature of the heat medium 91 flowing through the heat medium circulation circuit 10b. The plurality of heat medium temperature detection sensors 35a are provided in the heat medium circulation circuit 10b, which connects the indoor unit 2 and the heat storage tank 6 with the heating intermediate heat exchanger 14a and the cooling intermediate heat exchanger 14b, and detect the temperature of the heat medium 91 flowing through the heat medium circulation circuit 10b.

[0105] A heat medium temperature detection sensor 35a is provided on each of the connecting heat medium pipes 5 connected to the user-side heat exchanger 30a of the indoor unit 2. The heat medium temperature detection sensor 35a measures the temperature of the heat medium 91 flowing to and from the indoor unit 2. That is, the heat medium temperature detection sensor 35a measures the temperature of the heat medium 91 flowing from the heat medium relay unit 3 to the indoor unit 2. The heat medium temperature detection sensor 35a also measures the temperature of the heat medium 91 returning from the indoor unit 2 to the heat medium relay unit 3.

[0106] A heat medium temperature detection sensor 35a is provided on each of the connecting heat medium pipes 5 connected to the high-temperature pipe 81, the medium-temperature pipe 82, and the low-temperature pipe 83 of the heat storage tank 6. The heat medium temperature detection sensor 35a measures the temperature of the heat medium 91 flowing to and from the heat storage tank 6. That is, the heat medium temperature detection sensor 35a measures the temperature of the heat medium 91 flowing from the heat medium relay unit 3 to the heat storage tank 6. The heat medium temperature detection sensor 35a also measures the temperature of the heat medium 91 returning from the heat storage tank 6 to the heat medium relay unit 3.

[0107] The indoor unit 2 has a user-side heat exchanger 30a that exchanges heat between the air and the heat medium 91. Note that Figs. 14 and 15 show indoor unit 2a and indoor unit 2b as examples of the indoor unit 2. The indoor unit 2 is a general term for the indoor unit 2a, indoor unit 2b, etc. Figs. 14 and 15 show two indoor units 2, the indoor unit 2a and the indoor unit 2b, but the heat storage air conditioning and hot water supply system 200 may have three or more indoor units. It is sufficient that the heat storage air conditioning and hot water supply system 200 includes at least one indoor unit 2.

[0108] The use-side heat exchanger 30a is provided in the heat medium circulation circuit 10b, and performs heat exchange between the air and the heat medium 91. More specifically, the use-side heat exchanger 30a performs heat exchange between the indoor air surrounding the use-side heat exchanger 30a and the heat medium 91 flowing inside the use-side heat exchanger 30a. In each indoor unit 2, the use-side heat exchanger 30a performs heat exchange between the heat medium 91 and the air in the air-conditioned space, thereby heating or cooling the air in the air-conditioned space.

[0109] In the heat storage air conditioning and hot water supply system 200, the heat medium 91 is supplied to a plurality of indoor units 2, and the air in the air-conditioned space is heated or cooled by the use-side heat exchanger 30a, thereby performing heating or cooling operation of the air-conditioned space.

[0110] The thermal storage air-conditioning and hot water supply system 200 heats or cools the heat medium 91 flowing through the heat medium circulation circuit 10b by performing heat exchange between the refrigerant flowing through the refrigerant circulation circuit 10a of the outdoor unit 1 and the heat medium 91 flowing through the heat medium circulation circuit 10b. The refrigerant is an example of a heat source fluid that flows through the outdoor unit 1, which is the heat source unit 1a of the thermal storage air-conditioning and hot water supply system 200.

[0111] The refrigerant circulation circuit 10a is formed by sequentially connecting the compressor 10, the refrigerant flow switching device 11, the air heat exchanger 12, the first expansion device 15a, the cooling intermediate heat exchanger 14b, the second expansion device 15b, the heating intermediate heat exchanger 14a, and the accumulator 16. The refrigerant circulation circuit 10a forms a flow path through which the refrigerant flows. The refrigerant circulation circuit 10a is a closed circuit formed in a ring shape. The refrigerant flows so as to circulate inside the refrigerant circulation circuit 10a.

[0112] The thermal storage air conditioning and hot water supply system 200 has a refrigerant piping 18, and a refrigerant circulation circuit 10a is formed by the refrigerant piping 18 and various devices such as the compressor 10 connected to the refrigerant piping 18. The compressor 10, the refrigerant flow switching device 11, the air heat exchanger 12, the first expansion device 15a, the cooling intermediate heat exchanger 14b, the second expansion device 15b, the heating intermediate heat exchanger 14a, and the accumulator 16 are connected by the refrigerant piping 18.

[0113] An example of operation of the refrigerant circulation circuit 10a is shown. In the refrigerant circulation circuit 10a, the refrigerant compressed by the compressor 10 flows from the outdoor unit 1 into the relay unit 3 and is supplied to the heating intermediate heat exchanger 14a, where it heats the heat medium 91. In the refrigerant circulation circuit 10a, the refrigerant that has heated the heat medium 91 is expanded by the second expansion device 15b and cooled by the cooling intermediate heat exchanger 14b. The refrigerant then returns from the relay unit 3 to the outdoor unit 1.

[0114] The heat medium circulation circuit 10b is formed by connecting the heating intermediate heat exchanger 14a, the first heat medium circulation pump 31a, the heat medium flow switching valve 32a, the heat medium flow control device 34a, the use-side heat exchanger 30a of the indoor unit 2, and the heat storage tank 6. The heat medium circulation circuit 10b is also formed by connecting the cooling intermediate heat exchanger 14b, the second heat medium circulation pump 31b, the heat medium flow switching valve 32a, the heat medium flow control device 34a, the use-side heat exchanger 30a of the indoor unit 2, and the heat storage tank 6. The heat medium circulation circuit 10b includes at least one of the multiple indoor units 2 and the heat storage tank 6.

[0115] The heat medium circulation circuit 10b forms a flow path through which the heat medium 91 flows. The heat medium circulation circuit 10b is formed in a ring shape. The heat medium 91 flows so as to circulate within the heat medium circulation circuit 10b. The thermal storage air-conditioning and hot water supply system 200 has a heat medium piping 28, and the heat medium circulation circuit 10b is configured by the heat medium piping 28 and various devices such as the heating related heat medium heat exchanger 14a and the cooling related heat medium heat exchanger 14b connected to the heat medium piping 28.

[0116] The heating intermediate heat exchanger 14a, the first heat medium circulation pump 31a, the heat medium flow switching valve 32a, the heat medium flow control device 34a, the user-side heat exchanger 30a of the indoor unit 2, and the heat storage tank 6 are connected by heat medium piping 28. The cooling intermediate heat exchanger 14b, the second heat medium circulation pump 31b, the heat medium flow switching valve 32a, the heat medium flow control device 34a, the user-side heat exchanger 30a of the indoor unit 2, and the heat storage tank 6 are connected by heat medium piping 28.

[0117] In other words, the heat storage air-conditioning and hot water supply system 200 has a heat medium circulation circuit 10b, through which the heat medium 91 circulates, configured between the heat medium relay unit 3 and the user-side heat exchanger 30a. In the heat storage air-conditioning and hot water supply system 200, the refrigerant circulating in the refrigerant circulation circuit 10a and the heat medium 91 circulating in the heat medium circulation circuit 10b exchange heat with each other in the heating intermediate heat exchanger 14a and the cooling intermediate heat exchanger 14b.

[0118] The heat source unit 1a and the heat medium relay unit 3 are connected by a connecting refrigerant pipe 4. The heat medium relay unit 3 is also connected to the indoor units 2a and 2b via a connecting heat medium pipe 5. That is, the indoor units 2 are connected to the heating intermediate heat exchanger 14a and the cooling intermediate heat exchanger 14b via the connecting heat medium pipe 5. In the thermal storage air conditioning and hot water supply system 200, the flow rate of the heat medium 91 that flows through the connecting heat medium pipe 5 and is supplied to the indoor units 2 is adjusted by a heat medium flow control device 34a. The connecting refrigerant pipe 4 is part of the pipe that constitutes the refrigerant pipe 18, and the connecting heat medium pipe 5 is part of the pipe that constitutes the heat medium pipe 28.

[0119] The heat storage tank 6 and the heat medium relay unit 3 are connected by a high-temperature pipe 81, a medium-temperature pipe 82, and a low-temperature pipe 83 via the connecting heat medium pipe 5. That is, the heat storage tank 6 is connected to the heating intermediate heat exchanger 14a and the cooling intermediate heat exchanger 14b via the high-temperature pipe 81, the medium-temperature pipe 82, and the low-temperature pipe 83. In the heat-storage air-conditioning and hot water supply system 200, the flow rate of the heat medium 91 that flows through the high-temperature pipe 81 and the low-temperature pipe 83 and is supplied to the heat storage tank 6 is adjusted by the heat medium flow control device 34a. The high-temperature pipe 81, the medium-temperature pipe 82, and the low-temperature pipe 83 are part of the pipes that make up the heat medium pipe 28.

[0120] The heat storage air conditioning and hot water supply system 200 has a control device 50 that controls the entire heat storage air conditioning and hot water supply system 200. The control device 50 controls the heat storage air conditioning and hot water supply system 200 by controlling various devices that make up the heat storage air conditioning and hot water supply system 200.

[0121] The control device 50 is configured by dedicated hardware or a CPU (Central Processing Unit, also called a central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, or processor) that executes programs stored in memory.

[0122] When the control device 50 is dedicated hardware, the control device 50 may be, for example, a single circuit, a composite circuit, an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a combination thereof. Each functional unit realized by the control device 50 may be realized by a separate piece of hardware, or each functional unit may be realized by a single piece of hardware.

[0123] When the control device 50 is a CPU, each function executed by the control device 50 is realized by software, firmware, or a combination of software and firmware. The software or firmware is written as a program and stored in memory. The CPU realizes each function of the control device 50 by reading and executing the program stored in memory. Here, the memory is, for example, a non-volatile or volatile semiconductor memory such as RAM, ROM, flash memory, EPROM, or EEPROM.

[0124] It should be noted that some of the functions of the control device 50 may be realized by dedicated hardware, and other functions may be realized by software or firmware.

[0125] The control device 50 controls the heat storage air conditioning and hot water supply system 200 based on preset settings. Alternatively, the control device 50 controls the heat storage air conditioning and hot water supply system 200 based on settings set by the user. The control device 50 also communicates with the outside air temperature detection sensor 37 and the heat medium temperature detection sensor 35a, and controls the heat storage air conditioning and hot water supply system 200 based on the outside air temperature detection sensor 37 and the heat medium temperature detection sensor 35a.

[0126] The control device 50 controls the compressor 10 by controlling the frequency of the compressor 10. The control device 50 controls the refrigerant flow switching device 11 to control the direction of refrigerant flow in the refrigerant circulation circuit 10a. The control device 50 controls the valve openings of the first expansion device 15a and the second expansion device 15b. The control device 50 may also control the first heat medium circulation pump 31a, the second heat medium circulation pump 31b, the first heat medium pump 31c1, the second heat medium pump 31c2, etc. to control the amount of heat medium 91 delivered.

[0127] The control device 50 controls the heat medium flow path switching valve 32a, the first flow path switching valve 32a1, and the second flow path switching valve 32a2 to switch the flow path of the heat medium circuit 10b and to switch the flow direction of the heat medium 91. The control device 50 controls the valve opening of the heat medium flow control device 34a to control the flow rate of the heat medium 91 flowing through the heat medium circuit 10b. For example, the control device 50 selects cooling, heating, cold heat storage, hot heat storage, hot water supply, or a combination thereof by controlling the multiple heat medium flow control devices 34a and the multiple heat medium flow path switching valves 32a based on detection information from the multiple heat medium temperature detection sensors 35a.

[0128] Fig. 16 is a circuit diagram showing the direction of flow of the circulating medium during thermal storage-based cooling and heating operation of the thermal storage air conditioning hot water supply system 200 according to embodiment 4. Fig. 17 shows the flow of the heat medium 91 during simultaneous cooling and heating operation using the thermal storage tank 6 in the thermal storage air conditioning hot water supply system 200. An example of an operating pattern of the thermal storage air conditioning hot water supply system 200 will be described using Fig. 16. Note that some of the reference numerals in Fig. 16 have been omitted to illustrate the flow of the heat medium 91.

[0129] While FIG. 16 explains the flow of the heat medium 91 using FIG. 15 , the same flow of the heat medium 91 also occurs in the thermal storage air-conditioning and hot water supply system 200 shown in FIG. 14 . The dotted arrows indicate the flow direction of the heat medium 91 for cooling, and the solid arrows indicate the flow direction of the heat medium 91 for heating. Furthermore, in FIG. 16 , the heat medium circulation circuit 10b shown in FIG. 15 is divided into fine dotted lines, coarse dotted lines, dashed-dotted lines, thin solid lines, and thick solid lines to clearly show the flow path and branching of the heat medium 91. In the case of the thermal storage air-conditioning and hot water supply system 200 shown in FIG. 14 , the high-temperature heat storage tank 71, described below, is the upper part 72a of the heat medium tank 72, and the low-temperature heat storage tank 73 is the lower part 72c of the heat medium tank 72 (see FIG. 1 ).

[0130] In the heat-storage air-conditioning and hot water supply system 200, a high-temperature heat medium 91 flows out of a high-temperature heat storage tank 71, passes through a high-temperature pipe 81 and a connecting heat medium pipe 5, and flows into the heat medium relay unit 3. The heat medium 91 is then sent to the user-side heat exchanger 30a of the indoor unit 2a that performs heating, heats the indoor air, and then flows into the heat medium tank 72 through the connecting heat medium pipe 5 and the medium-temperature pipe 82.

[0131] On the other hand, in the heat-storage air-conditioning and hot water supply system 200, the low-temperature heat medium 91 flowing out of the low-temperature heat storage tank 73 passes through the low-temperature pipe 83 and the connecting heat medium pipe 5 and flows into the heat medium relay unit 3. The heat medium 91 is then sent to the user-side heat exchanger 30a of the indoor unit 2b that performs cooling, cools the indoor air, and then flows into the heat medium tank 72 through the connecting heat medium pipe 5 and the medium-temperature pipe 82.

[0132] Fig. 17 is a circuit diagram showing the direction of flow of the circulating medium during simultaneous cold and hot heat storage operation of the heat storage air conditioning and hot water supply system 200 according to embodiment 4. Fig. 17 shows the flow of the heat medium 91 when cold heat and hot heat are stored simultaneously in the heat storage tank 6. An example of an operation pattern of the heat storage air conditioning and hot water supply system 200 will be described using Fig. 17. Note that in Fig. 17, some of the reference numerals are omitted in order to explain the flow of the heat medium 91.

[0133] While FIG. 17 explains the flow of the heat medium 91 using FIG. 15 , the heat medium 91 also flows in the heat-storage air-conditioning and hot water supply system 200 shown in FIG. 14 in a similar manner. The dotted arrows indicate the flow direction of the heat medium 91 that stores low-temperature heat, and the solid arrows indicate the flow direction of the heat medium 91 that stores high-temperature heat. Furthermore, in FIG. 17 , the heat medium circulation circuit 10b shown in FIG. 15 is shown using dotted lines, dashed lines, thin solid lines, and thick solid lines to clearly show the flow path and branching of the heat medium 91. In the case of the heat-storage air-conditioning and hot water supply system 200 shown in FIG. 14 , the high-temperature heat storage tank 71 described below is the upper portion 72a of the heat medium tank 72, and the low-temperature heat storage tank 73 is the lower portion 72c of the heat medium tank 72 (see FIG. 1 ).

[0134] In the heat storage air conditioning and hot water supply system 200, a portion of the heat medium 91 that flows out of the heat medium tank 72 and passes through the medium-temperature pipe 82 and the connecting heat medium pipe 5 is supplied to the heating intermediate heat exchanger 14a. The heat medium 91 heated by the heating intermediate heat exchanger 14a flows into the high-temperature heat storage tank 71 through the connecting heat medium pipe 5 and the high-temperature pipe 81.

[0135] In the heat storage air conditioning and hot water supply system 200, the remaining heat medium 91 out of the heat medium tank 72 and passing through the medium-temperature pipe 82 and the connecting heat medium pipe 5 is supplied to the cooling intermediate heat exchanger 14b. The heat medium 91 cooled by the cooling intermediate heat exchanger 14b flows into the low-temperature heat storage tank 73 through the connecting heat medium pipe 5 and the low-temperature pipe 83. The amount of heat medium 91 supplied to each of the heating intermediate heat exchanger 14a and the cooling intermediate heat exchanger 14b is adjusted by a heat medium flow control device 34a provided on the connecting heat medium pipe 5 connected to the high-temperature pipe 81 and the low-temperature pipe 83.

[0136] Fig. 18 is a circuit diagram showing the direction of flow of the circulating medium during simultaneous cold and hot heat storage and simultaneous cooling and heating operation of the heat storage air conditioning and hot water supply system 200 according to embodiment 4. Fig. 18 shows the flow of the heat medium 91 in an operation pattern in which cooling, heating, cold heat storage, and hot heat storage are performed simultaneously. An example of an operation pattern of the heat storage air conditioning and hot water supply system 200 will be described using Fig. 18. Note that some of the reference numerals in Fig. 18 are omitted to illustrate the flow of the heat medium 91.

[0137] While FIG. 18 explains the flow of the heat medium 91 using FIG. 15 , the same flow of the heat medium 91 also occurs in the heat-storage air-conditioning and hot water supply system 200 shown in FIG. 14 . The dotted arrows indicate the flow direction of the heat medium 91 that stores low-temperature heat and performs cooling, while the solid arrows indicate the flow direction of the heat medium 91 that stores high-temperature heat and performs heating. Furthermore, in FIG. 18 , the heat medium circulation circuit 10b shown in FIG. 15 is divided into fine dotted lines, coarse dotted lines, dashed dotted lines, thin solid lines, and thick solid lines to clearly show the flow path and branching of the heat medium 91. In the case of the heat-storage air-conditioning and hot water supply system 200 shown in FIG. 14 , the high-temperature heat storage tank 71 described below is the upper part 72a of the heat medium tank 72, and the low-temperature heat storage tank 73 is the lower part 72c of the heat medium tank 72 (see FIG. 1 ).

[0138] The heat storage air conditioning and hot water supply system 200 is configured so that a portion of the heat medium 91 heated by the heating intermediate heat exchanger 14a is supplied to the user-side heat exchanger 30a of the indoor unit 2a that performs heating, heats the air in the air-conditioned space, and then returns to the heating intermediate heat exchanger 14a.

[0139] The heat-storage air-conditioning and hot water supply system 200 is configured so that the remaining heat medium 91 heated by the heating intermediate heat exchanger 14a flows through the connecting heat medium piping 5 and the high-temperature piping 81 into the high-temperature heat storage tank 71 in the heat storage tank 6. The heat medium 91 that flows into the high-temperature heat storage tank 71 exchanges heat with the high-temperature heat storage material 90a in the high-temperature heat storage tank 71, then passes through the heat medium tank 72 and flows out of the heat medium tank 72, passes through the medium-temperature piping 82 and the connecting heat medium piping 5, and returns to the heating intermediate heat exchanger 14a again.

[0140] The heat storage air conditioning and hot water supply system 200 is configured so that a portion of the heat medium 91 cooled by the cooling intermediate heat exchanger 14b is supplied to the user-side heat exchanger 30a of the indoor unit 2b that performs cooling, cools the air in the air-conditioned space, and then returns to the cooling intermediate heat exchanger 14b.

[0141] The heat storage air conditioning and hot water supply system 200 is configured so that the remaining cooled heat medium 91 of the heat medium 91 cooled by the cooling intermediate heat exchanger 14b flows through the connecting heat medium piping 5 and the low-temperature piping 83 into the low-temperature heat storage tank 73 in the heat storage tank 6. The heat medium 91 that flows into the low-temperature heat storage tank 73 exchanges heat with the low-temperature heat storage material 90b in the low-temperature heat storage tank 73, then passes through the heat medium tank 72 and flows out of the heat medium tank 72, passes through the medium-temperature piping 82 and the connecting heat medium piping 5, and returns to the cooling intermediate heat exchanger 14b again.

[0142] 14 and 15 can perform hot water supply operation using the hot water heat exchanger 74 as described above by circulating the heat medium 91 using the first heat medium pump 31c1 provided in the heat storage tank 6. Therefore, the heat storage air conditioning and hot water supply system 200 can perform hot water supply operation while simultaneously performing cooling or heating operation using the outdoor unit 1 and the heat medium relay unit 3.

[0143] [Operation and Effect of the Thermal Storage Air Conditioning and Hot Water Supply System 200] The thermal storage air conditioning and hot water supply system 200 includes the thermal storage tank 6 according to any one of the first to third embodiments, a plurality of indoor units 2 having a user-side heat exchanger 30a that exchanges heat between air and a heat medium 91, and a heat medium circulation circuit 10b that includes at least one of the indoor units 2 and the thermal storage tank 6. The thermal storage air conditioning and hot water supply system 200 also includes a heating-intermediate heat exchanger 14a that exchanges heat between the heat source fluid of the heat source unit 1a and the heat medium 91 circulating in the heat medium circulation circuit 10b to heat the heat medium 91. The thermal storage air conditioning and hot water supply system 200 also includes a cooling-intermediate heat exchanger 14b that exchanges heat between the heat source fluid of the heat source unit 1a and the heat medium 91 circulating in the heat medium circulation circuit 10b to cool the heat medium 91.

[0144] The heat storage air conditioning and hot water supply system 200 includes a first heat medium circulation pump 31a provided in a heat medium circulation circuit 10b corresponding to the heating intermediate heat exchanger 14a and a second heat medium circulation pump 31b provided in a heat medium circulation circuit 10b corresponding to the cooling intermediate heat exchanger 14b. The heat storage air conditioning and hot water supply system 200 also includes a plurality of heat medium flow switching valves 32a provided in the heat medium circulation circuit 10b for switching the connection destinations of the indoor units 2 and the heat storage tank 6 with respect to the heating intermediate heat exchanger 14a and the cooling intermediate heat exchanger 14b. The heat storage air conditioning and hot water supply system 200 also includes a plurality of heat medium flow control devices 34a provided in the heat medium circulation circuit 10b for controlling the flow rate of the heat medium 91 and a plurality of heat medium temperature detection sensors 35a for detecting the temperature of the heat medium 91.

[0145] The thermal storage air conditioning and hot water supply system 200 selects cooling, heating, cold heat storage, hot heat storage, hot water supply, or a combination of these modes by controlling multiple heat medium flow selector valves 32a and multiple heat medium flow rate regulators 34a based on detection information from the heat medium temperature detection sensor 35a. Conventional thermal storage air conditioning and hot water supply systems that do not include a thermal storage tank 6 require the operation of a heat source unit when air conditioning is required. In contrast, the thermal storage air conditioning and hot water supply system 200 can perform air conditioning using heat stored in the thermal storage tank 6, thereby storing inexpensive nighttime electricity or low-temperature exhaust heat from heating operation to provide cooling when needed. This allows the thermal storage air conditioning and hot water supply system 200 to reduce the power consumption costs required for air conditioning compared to conventional thermal storage air conditioning and hot water supply systems that do not include a thermal storage tank 6. Furthermore, because the thermal storage air conditioning and hot water supply system 200 includes a thermal storage tank 6, it exhibits the same effects as the thermal storage tank 6 of the first to third embodiments.

[0146] REFERENCE SIGNS LIST 1 outdoor unit, 1a heat source unit, 2 indoor unit, 2a indoor unit, 2b indoor unit, 3 heat medium converter, 4 connecting refrigerant piping, 5 connecting heat medium piping, 6 heat storage tank, 10 compressor, 10a refrigerant circulation circuit, 10b heat medium circulation circuit, 11 refrigerant flow switching device, 12 air heat exchanger, 14a heating heat medium heat exchanger, 14b cooling heat medium heat exchanger, 15a first expansion device, 15b second expansion device, 16 accumulator, 18 refrigerant piping, 28 heat medium piping, 30a use side heat exchanger, 31a first heat medium circulation pump, 31b second heat medium circulation pump, 31c1 first heat medium pump, 31c2 second heat medium pump, 32a heat medium flow switching valve, 32a1 first flow switching valve, 32a2 second flow switching valve, 34a Heat medium flow rate control device, 35a heat medium temperature detection sensor, 37 outdoor air temperature detection sensor, 50 control device, 71 high temperature heat storage tank, 72 heat medium tank, 72a upper part, 72b central part, 72c lower part, 73 low temperature heat storage tank, 74 hot water supply heat exchanger, 75 heat storage heat exchanger, 75a high temperature heat storage heat exchanger, 75b low temperature heat storage heat exchanger, 76 water supply port, 77 hot water supply port, 78 water piping, 81 high temperature piping, 82 medium temperature piping, 83 low temperature piping, 84a medium temperature piping switching valve, 86 first piping, 87 second piping, 90 latent heat storage material, 90a high temperature heat storage material, 90b low temperature heat storage material, 91 heat medium, 100 heat source, 101 cold heat source, 200 heat storage air conditioning hot water supply system.

Claims

a first heat medium pump connected to the high-temperature pipe and causing the heat medium to flow into the heat medium tank and to flow out of the heat medium tank; a second heat medium pump connected to the low-temperature pipe and causing the heat medium to flow into the heat medium tank and to flow out of the heat medium tank; a first pipe connecting the high-temperature pipe and the medium-temperature pipe; a second pipe connecting the first pipe and the low-temperature pipe; a first flow path switching valve connected to the first pipe and the second pipe and switching the flow path through which the heat medium flows; A heat storage tank that switches between low-temperature heat storage operation, high-temperature heat storage operation, heat release operation, and simultaneous operation of each of the low-temperature heat storage operation, high-temperature heat storage operation, and heat release operation, by using the first flow path switching valve and the second flow path switching valve to switch the flow path of the heat medium flowing inside the high-temperature pipe, the medium-temperature pipe, and the low-temperature pipe.

2. The heat storage tank according to claim 1, further comprising: a high-temperature heat storage tank connected in the high-temperature piping between a connection portion of the first piping and the heat medium tank; and a low-temperature heat storage tank connected in the low-temperature piping between the second flow path switching valve and the heat medium tank, wherein the high-temperature heat storage tank has therein a high-temperature heat storage material that exchanges heat with the heat medium and has a larger heat storage amount than the heat medium, and a high-temperature heat storage heat exchanger through which the heat medium circulates and exchanges heat with the high-temperature heat storage material, and the low-temperature heat storage tank has therein a low-temperature heat storage material that exchanges heat with the heat medium and has a larger heat storage amount than the heat medium, and a low-temperature heat storage heat exchanger through which the heat medium circulates and exchanges heat with the low-temperature heat storage material, and wherein the high-temperature heat storage tank, the heat medium tank, and the low-temperature heat storage tank are connected in series.

3. A heat storage tank as described in claim 1 or 2, wherein the medium temperature piping is branched into at least two and connected to the heat medium tank, and the medium temperature piping has a medium temperature piping switching valve at the branched portion, and the medium temperature piping switching valve is used to change the volume in the heat medium flow path during heat storage operation according to the amount of heat stored at a required temperature, thereby adjusting the amount of low temperature heat storage and the amount of high temperature heat storage.

4. A heat storage tank as described in any one of claims 1 to 3, comprising a hot water heat exchanger connected to the high-temperature pipe and a water pipe through which water flows, and which exchanges heat between the heat medium flowing through the high-temperature pipe and the water flowing through the water pipe.

5. A heat storage tank according to any one of claims 1 to 4; a plurality of indoor units having a user side heat exchanger that exchanges heat between air and the heat medium; a heat medium circulation circuit including at least one of the plurality of indoor units and the heat storage tank; a heating inter-heat medium heat exchanger that exchanges heat between a heat source fluid of a heat source unit and the heat medium circulating in the heat medium circulation circuit to heat the heat medium; a cooling inter-heat medium heat exchanger that exchanges heat between the heat source fluid of the heat source unit and the heat medium circulating in the heat medium circulation circuit to cool the heat medium; a first heat medium circulation pump provided in the heat medium circulation circuit corresponding to the heating inter-heat medium heat exchanger; and a second heat medium circulation pump provided in the heat medium circulation circuit corresponding to the cooling inter-heat medium heat exchanger. a plurality of heat medium flow path switching valves that are provided in the heat medium circulation circuit connecting the indoor unit and the heat storage tank to the heating inter-heat medium heat exchanger and the cooling inter-heat medium heat exchanger, and switch the connection destination of the indoor unit and the heat storage tank to the heating inter-heat medium heat exchanger and the cooling inter-heat medium heat exchanger; a plurality of heat medium flow rate adjustment devices that are provided in the heat medium circulation circuit connecting the indoor unit and the heat storage tank to the heating inter-heat medium heat exchanger and the cooling inter-heat medium heat exchanger, and control the flow rate of the heat medium; a plurality of heat medium temperature detection sensors that are provided in the heat medium circulation circuit connecting the indoor unit and the heat storage tank to the heating inter-heat medium heat exchanger and the cooling inter-heat medium heat exchanger, and detect the temperature of the heat medium; A heat storage air conditioning and hot water supply system that selects cooling, heating, cold heat storage, hot heat storage, hot water supply, or a combination of these operations by controlling the multiple heat medium flow path switching valves and the multiple heat medium flow rate control devices based on detection information from the multiple heat medium temperature detection sensors.

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