Storage tank unit

Abstract

A storage tank unit (50) comprises a storage tank (51) that stores fluid, a first partition (81a) disposed inside the storage tank (51), and a second partition (81b) disposed on the inside of the first partition (81a). A first flow path (43) having an annular horizontal cross section is formed between the first partition (81a) and the second partition (81b). A second flow path (44) having an annular horizontal cross section is formed between the first partition (81a) and the inner surface of the side walls (56) of the storage tank (51). The storage tank unit (50) is provided with heating units (52a, 52b, 52d, 52e) that heat the fluid in the first flow path (43).

Description

Technical Field

[0001] The present disclosure relates to a storage tank unit.

Background Art

[0002] Conventionally, a storage tank unit having a storage tank for storing water and a heat exchanger provided inside the storage tank is known. For example, the storage tank disclosed in Patent Document 1 includes a heat exchanger formed in a spiral shape and a baffle plate. Water near the heat exchanger is heated, causing convection of water in the storage tank. The baffle plate provided inside the heat exchanger promotes the convection of water.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a user wants to supply hot water from the storage tank to a hot water supply object such as a bathtub, it is desirable to efficiently raise the temperature of the water in the tank.

[0005] An object of the present disclosure is to provide a storage tank unit that can efficiently raise the temperature of the fluid in the storage tank.

Means for Solving the Problems

[0006] A first aspect of the present disclosure is a storage tank unit comprising a storage tank (51) for storing a fluid, a first partition (81a) disposed inside the storage tank (51) and extending in a direction along the side wall (56) of the storage tank (51), and a second partition (81b) disposed inside the first partition (81a) and extending in a direction along the side wall (56) of the storage tank (51), wherein the first partition (81a) and the second partition (81b) The device is characterized by having heating sections (52a, 52b, 52d, 52e) that heat the fluid in the first passage (43), which is heated by heating

[0007] In the first embodiment, in the storage tank (51), the fluid in the first channel (43) is heated by the heating section (52a, 52b, 52d, 52e). As a result, an upward flow is formed in the first channel (43). The first channel (43) is formed to extend in a direction along the side wall (56) of the storage tank (51). This increases the flow velocity of the upward flow in the first channel (43), thereby promoting heat transfer from the heating section (51a, 52b, 52d, 52e) to the fluid. The first partition (81a) and the second partition (81b) are positioned spaced apart from the bottom surface of the storage tank (51). As a result, in the second channel (44), a downward flow is formed flowing from the lower end of the second channel (44) into the first channel (43). The second channel (44) is formed outside the first channel (43). Therefore, obstruction of the upward flow in the first channel (43) by the downward flow in the second channel (44) can be suppressed. This makes it possible to increase the flow velocity of the upward flow in the first channel (43). Here, the first partition (81a) also includes cases where there is a gap between the inside and outside of the first partition (81a) through which fluid can flow in and out. The second partition (81b) also includes cases where there is a gap between the inside and outside of the second partition (81b) through which fluid can flow in and out.

[0008] A second aspect of the present disclosure is, in the first aspect, that the heating section (52a, 52b, 52d, 52e) is a heat exchanger (52a, 52b) having spiral heat transfer tubes (53), and at least one of the first partition section (81a) and the second partition section (81b) also serves as a heat exchanger (52a, 52b).

[0009] In the second embodiment, the first flow path (43) is formed between the first partition (81a) and the second partition (81b). The partitions (81a, 81b) themselves act as heat exchangers (52a, 52b), allowing the first flow path (43) to be heated while rectifying the flow from its lower end to its upper end. This increases the flow velocity of the upward flow in the first flow path (43), and consequently promotes heat transfer from the heat exchangers (52a, 52b) to the fluid.

[0010] A third aspect of the present disclosure is characterized in that, in the second aspect, the first partition (81a) and the second partition (81b) are heat exchangers (52a, 52b) having spiral heat transfer tubes (53).

[0011] In the third embodiment, the fluid in the first channel (43) is heated by the first partition (81a) and the second partition (81b), which are heat exchangers (52a, 52b). This allows the fluid in the first channel (43) to be heated efficiently.

[0012] A fourth aspect of the present disclosure is characterized in that, in the second or third aspect, the heat transfer tube (53) comprises a plurality of heat transfer sections (57, 57, ...) arranged in the vertical direction, wherein the first distance (D1) between adjacent heat transfer sections (57, 57) in the vertical direction is smaller than the second radial distance (D2) between the first partition section (81a) and the second partition section (81b).

[0013] In the fourth embodiment, the flow of fluid between adjacent heat transfer sections (57, 57) in the vertical direction can be suppressed. This suppresses the attenuation of the flow velocity of the upward flow of fluid.

[0014] A fifth aspect of the present disclosure is, in the first aspect, a heat exchanger (52d, 52e) having spiral heat transfer tubes (53) arranged between the first partition (82a) and the second partition (81b), and having spiral heat transfer tubes (53) arranged along the first partition (82a) and the second partition (82b).

[0015] In the fifth embodiment, the first flow path (43) is a space partitioned by a first partition plate (82a) and a second partition plate (82b). The heat exchangers (52d, 52e) are placed within the first flow path (43). This allows heating while rectifying the upward flow in the first flow path (43). As a result, the flow velocity of the upward flow in the first flow path (43) can be increased, and consequently, heat transfer from the heat exchangers (52d, 52e) to the fluid can be promoted.

[0016] A sixth aspect of the present disclosure is, in the fifth aspect, the heat transfer tube (53) comprises a plurality of heat transfer sections (57, 57, ...) arranged in the vertical direction, wherein the first distance (D1) between adjacent heat transfer sections (57, 57) in the vertical direction is smaller than the third radial distance (D3) between the first partition plate (82a) and the heat transfer tube (53), and the fourth radial distance (D4) between the second partition plate (82b) and the heat transfer tube (53).

[0017] In the sixth embodiment, the upward flow of the first flow path (43) can be suppressed from flowing between adjacent heat transfer sections (57, 57) in the vertical direction. This suppresses the attenuation of the flow velocity of the upward flow of the fluid.

[0018] A seventh aspect of the present disclosure, in the second, third, or fifth aspect, is characterized in that the heat transfer tube (53) comprises a plurality of heat transfer sections (57, 57, ...) arranged in the vertical direction, wherein adjacent heat transfer sections (57, 57) in the vertical direction are in contact with each other.

[0019] In the seventh aspect, it is possible to prevent the upward flow of the first flow path (43) from flowing between the heat transfer portions (57, 57) adjacent to each other in the vertical direction. By this, it is possible to suppress the attenuation of the flow velocity of the upward flow of the fluid.

[0020] In the eighth aspect of the present disclosure, in any one of the second to seventh aspects, an inlet (59) of the heat transfer tube (53) is provided at an upper end of the heat transfer tube (53), and an outlet (60) of the heat transfer tube (53) is provided at a lower end of the heat transfer tube (53).

[0021] In the eighth aspect, the heat medium flowing through the heat transfer tube (53) and the fluid flowing through the first flow path (43) are substantially in a countercurrent flow. Therefore, the fluid in the first flow path (43) can be efficiently heated.

[0022] In the ninth aspect of the present disclosure, in any one of the second to eighth aspects, in a cross-sectional view perpendicular to the axis of the heat transfer tube (53), a vertical length (H) from the lower end to the upper end of the heat transfer tube (53) is longer than a horizontal length (W) between side ends on both sides of the heat transfer tube (53).

[0023] In the ninth aspect, in the first flow path (43), it is possible to increase the contact area with the ascending fluid, and promote heat transfer from the heat transfer tube (53) to the fluid.

[0024] In the tenth aspect of the present disclosure, in any one of the first to seventh aspects, a rectifying plate (71) is provided above the first flow path (43) and guides the fluid ascending through the first flow path (43) toward the center side of the storage tank (51).

[0025] In the tenth aspect, the rectifying plate can suppress the collision between the upward flow generated in the first flow path (43) and the downward flow close to the side wall (56) of the storage tank (51).

[0026] In the eleventh aspect of the present disclosure, in any one of the first to tenth aspects, the first partition portion (81a), the second partition portion (81b), and the heating portions (52a, 52b, 52d, 52e) are provided only at the lower part of the storage tank (51).

[0027] In the eleventh aspect, a space where fluid can对流 is secured above the storage tank (51).

[0028] The twelfth aspect of the present disclosure is a water supply device (20) provided with a storage tank unit for storing water, characterized by including the storage tank unit (50) according to any one of the first to eleventh aspects.

Brief Description of the Drawings

[0029] [Figure 1] FIG. 1 is a piping system diagram showing the overall configuration of a storage tank unit according to an embodiment. [Figure 2] FIG. 2 is a view showing a cross-section perpendicular to the axis of a part of a heat transfer pipe. [Figure 3] FIG. 3 is a schematic diagram showing the flow of fluid in a storage tank heated by a heat exchanger. [Figure 4] FIG. 4 is a view corresponding to FIG. 3 according to Modification 1 of the embodiment. [Figure 5] FIG. 5 is a view corresponding to FIG. 3 according to Modification 2 of the embodiment. [Figure 6] FIG. 6 is a view corresponding to FIG. 3 according to Modification 3 of the embodiment. [Figure 7] FIG. 7 is a view corresponding to FIG. 3 according to Modification 4 of the embodiment. [Figure 8] FIG. 8 is a view corresponding to FIG. 3 according to Modification 5 of the embodiment. [Figure 9] FIG. 9 is a view corresponding to FIG. 2 showing an embodiment different from the embodiment. [Figure 10] FIG. 10 is a view corresponding to FIG. 2 showing an embodiment different from the embodiment. [[ID=​​​

[0030] 《Embodiment》 The hot water supply system (20) of this disclosure applies to a heat pump type hot water supply unit (1). The hot water supply unit (1) heats water supplied from a water source (S) and stores the heated hot water in a storage tank (51). The hot water in the storage tank (51) is supplied to a predetermined hot water supply target (T). The water source (S) is a line from which water is supplied, including a public water supply. The hot water supply target (T) is an object from which hot water is used, including showers, faucets, bathtubs, etc.

[0031] As shown in Figure 1, the hot water supply unit (1) has a heat source device (10) and a hot water supply device (20). The heat source device (10) has a refrigerant circuit (11). The hot water supply device (20) has a heating channel (30) and a hot water supply channel (40). The heating channel (30) is a channel through which water, which is the heat transfer medium, flows. The hot water supply channel (40) is a water channel formed between the water source (S) and the object to be supplied with hot water (T). The hot water supply unit (1) has a water heat exchanger (13). The refrigerant circuit (11) and the heating channel (30) are connected to each other via the water heat exchanger (13).

[0032] <Heat source device> The heat source device (10) is a heat source for generating hot water. The refrigerant circuit (11) of the heat source device (10) is filled with a refrigerant. As the refrigerant, for example, a fluorocarbon refrigerant or a natural refrigerant such as propane is used. In the refrigerant circuit (11), a vapor compression type refrigeration cycle is carried out by the circulation of the refrigerant.

[0033] The refrigerant circuit (11) includes a compressor (12), a water heat exchanger (13), an expansion valve (14), and an air heat exchanger (15).

[0034] The compressor (12) draws in low-pressure refrigerant and compresses it. The compressor (12) discharges the refrigerant that has been compressed to high pressure.

[0035] The water heat exchanger (13) heats the water in the heating channel (30). The water heat exchanger (13) has a refrigerant channel (13a) and a water channel (13b). The water heat exchanger (13) exchanges heat between the refrigerant flowing through the refrigerant channel (13a) and the water, which is the heat transfer medium, flowing through the water channel (13b). The water heat exchanger (13) constitutes a heat exchanger (condenser) from which the refrigerant releases heat.

[0036] The expansion valve (14) constitutes a pressure reduction mechanism that reduces the pressure of the refrigerant. The expansion valve (14) reduces the pressure of the high-pressure refrigerant to a low-pressure refrigerant. The expansion valve (14) is composed of, for example, an electronic expansion valve.

[0037] The air heat exchanger (15) exchanges heat between air and refrigerant. The air heat exchanger (15) is installed outdoors. An outdoor fan (16) is installed near the air heat exchanger (15). The air transported by the outdoor fan (16) passes through the air heat exchanger (15). In the air heat exchanger (15), the refrigerant absorbs heat from the outdoor air and evaporates. The air heat exchanger (15) constitutes an evaporator.

[0038] <Hot water supply system> The hot water supply system (20) includes a heating channel (30), a hot water supply channel (40), and a storage tank unit (50).

[0039] <Heating channel> The heating channel (30) includes a water heat exchanger (13), a storage tank unit (50), an inlet pipe (31), an outlet pipe (32), and a pump (33).

[0040] The storage tank unit (50) comprises a storage tank (51), a first partition (81a), a second partition (81b), and heating units (52a, 52b). The storage tank (51) stores water, which is a fluid, inside. The first partition (81a) is located inside the storage tank (51). The first partition (81a) is formed in a cylindrical shape extending along the side wall (56) of the storage tank (51). The second partition (81b) is located inside the first partition (81a). The second partition (81b) is formed in a cylindrical shape extending along the side wall (56) of the storage tank (51). A first flow channel (43) with an annular horizontal cross-section is formed between the first partition (81a) and the second partition (81b). The water in the storage tank (51) is heated in the first flow path (43) by the heating sections (52a, 52b).

[0041] The outflow pipe (32) is a pipe that sends the water in the heat transfer tubes (53), which has absorbed heat in the storage tank (51), to the water heat exchanger (13). The inflow end of the outflow pipe (32) is connected to the outflow end of the heat transfer tubes (53). The outflow end of the outflow pipe (32) is connected to the inflow end of the water flow path (13b) of the water heat exchanger.

[0042] The water heat exchanger (13) is equipped with a water flow path (13b). In the water heat exchanger (13), the water flowing in from the outlet pipe (32) is heated by the refrigerant.

[0043] The inlet pipe (31) is a pipe that sends water heated by the water heat exchanger (13) to the storage tank (51). The inlet end of the inlet pipe (31) is connected to the outlet end of the water channel (13b). The outlet end of the inlet pipe (31) is connected to the inlet end of the heat transfer tube (53) inside the storage tank (51).

[0044] The pump (33) is a conveying device that transports water in the heating channel (30). The pump (33) is installed in the outlet pipe (32).

[0045] <Hot water supply flow path> The hot water supply channel (40) includes a water supply pipe (41) and a hot water supply pipe (42).

[0046] The water supply pipe (41) is an inflow channel that connects the water source (S) and the storage tank (51). The upstream end of the water supply pipe (41) is connected to, for example, the water supply piping. The downstream end of the water supply pipe (41) is connected to the bottom (54) of the storage tank (51). The water supply pipe (41) supplies cold water from the water source (S) to the storage tank (51) as needed. Specifically, when water from the storage tank (51) is supplied to the hot water supply target (T), the internal pressure of the storage tank (51) decreases. Consequently, the water supply pipe (41) and the storage tank (51) As the pressure difference increases, cold water from the water source (S) is supplied to the storage tank (51) via the water supply pipe (41).

[0047] The hot water supply pipe (42) is an outflow channel that connects the storage tank (51) and the hot water supply target (T). The upstream end of the hot water supply pipe (42) is connected to the top (55) of the storage tank (51).

[0048] Water flowing from the water supply pipe (41) into the storage tank (51) is heated inside the storage tank (51) and flows out into the hot water supply pipe (42). The water in the hot water supply pipe (42) passes through the hot water supply pipe (42) and is supplied to the hot water supply target (T).

[0049] -Storage Tank Unit- The storage tank unit (50) includes a storage tank (51), a first partition (81a), a second partition (81b), and heating sections (52a, 52b). In this embodiment, the first partition (81a) and the second partition (81b) also serve as the heating sections (52a, 52b). The heating sections (52a, 52b) are heat exchangers (52a, 52b) having spiral heat transfer tubes (53).

[0050] <Storage Tank> The storage tank (51) is formed in a vertically elongated cylindrical shape. The storage tank (51) has a cylindrical side wall (56), a bottom (54) that closes the lower end of the side wall (56), and a top (55) that closes the upper end of the side wall (56). Water, which is a fluid, is stored inside the storage tank (51).

[0051] <Heat exchanger> The first partition (81a) also serves as the first heat exchanger (52a). The heat transfer tubes (53) of the first heat exchanger (52a) are formed in a roughly cylindrical shape. Specifically, the heat transfer tubes (53) of the first heat exchanger (52a) are formed in a spiral shape along the inner circumference of the storage tank (51).

[0052] The second partition (81b) also serves as the second heat exchanger (52b). The heat transfer tubes (53) of the second heat exchanger (52b) are formed in a roughly cylindrical shape. Specifically, the heat transfer tubes (53) of the second heat exchanger (52b) are positioned inside the first heat exchanger (52a) and are formed in a spiral shape. The central axes of the heat transfer tubes (53) of the first heat exchanger (52a) and the heat transfer tubes (53) of the second heat exchanger (52b) coincide.

[0053] Both heat exchangers (52a, 52b) are installed only at the bottom of the storage tank (51). Both heat exchangers (52a, 52b) are positioned spaced apart from the bottom surface of the storage tank (51).

[0054] As shown in Figure 2, the heat transfer tube (53) is composed of multiple heat transfer sections (57, 57, ...) that are adjacent to each other in the vertical direction. Each heat transfer section (57) is a single turn of the heat transfer tube (53). A gap is formed between the heat transfer sections (57, 57) that are adjacent to each other in the vertical direction. Water, which is a fluid, flows through this gap, and the heat transfer tube (53) encourages the flow direction of the water in the first flow path (43) and the second flow path (44), which will be described later, to be vertical. Specifically, the distance between the heat transfer sections (57, 57) that are adjacent to each other in the vertical direction is defined as the first distance (D1). The radial distance between the first heat exchanger (52a) and the second heat exchanger (52b) is defined as the second distance (D2). The second distance (D2) is the radial distance between the inner end of the heat transfer tube (53) of the first heat exchanger (52a) and the outer end of the heat transfer tube (53) of the second heat exchanger (52b). The first distance (D1) is smaller than the second distance (D2).

[0055] Inlets (59, 59) into which the heat transfer medium flows are formed in the heat transfer tubes (53) of the first heat exchanger (52a) and the heat transfer tubes (53) of the second heat exchanger (52b). Each inlet (59) is located at the upper end of each heat transfer tube (53). The inlets (59) of the first heat exchanger (52a) and the inlets (59) of the second heat exchanger (52b) are connected to the outlet end of the inlet pipe (31).

[0056] Outlets (60,60) for the heat transfer medium are formed in the heat transfer tubes (53) of the first heat exchanger (52a) and the heat transfer tubes (53) of the second heat exchanger (52b). Each outlet (60) is located at the lower end of each heat transfer tube (53). The outlet (60) of the first heat exchanger (52a) and the outlet (60) of the second heat exchanger (52b) are connected to the outlet end of the outlet pipe (32).

[0057] <First channel, second channel, and surrounding space> A first flow path (43) is formed between the first heat exchanger (52a) and the second heat exchanger (52b). The first flow path (43) is a fluid flow path. Specifically, the inner circumferential surface of the first heat exchanger (52a) and the second A first flow channel (43) is formed between the outer circumferential surfaces of two heat exchangers (52b). The first flow channel (43) extends in a direction along the side wall of the storage tank (51). The horizontal cross-section of the first flow channel (43) is annular.

[0058] A second flow path (44) is formed between the first heat exchanger (52a) and the inner surface of the side wall (56) of the storage tank (51). The second flow path (44) is a fluid flow path. Specifically, the second flow path (44) is formed between the outer surface of the first heat exchanger (52a) and the inner surface of the side wall (56) of the storage tank (51). The second flow path (44) extends in a direction along the side wall of the storage tank (51). The horizontal cross-section of the second flow path (44) is annular.

[0059] An internal space (45) is formed inside the heat transfer tubes (53) of the second heat exchanger (52b). A bottom space (46) is formed between the bottoms of both heat exchangers (52a, 52b) and the storage tank (51). An upper space (47) is formed above both heat exchangers (52a, 52b).

[0060] -Operation- The hot water supply unit (1) performs a heating operation to heat the water in the storage tank (51) and a hot water supply operation to supply the heated water from the storage tank (51) to the hot water supply target (T).

[0061] During heating operation, the heat source device (10) shown in Figure 1 is operated and the pump (33) is turned ON. When the heat source device (10) is operating during heating operation, the compressor (12) is driven and the opening degree of the expansion valve (14) is adjusted.

[0062] In the refrigerant circuit (11), a refrigeration cycle takes place. Specifically, the refrigerant compressed by the compressor (12) flows through the refrigerant passage (13a) of the water heat exchanger (13). In the water heat exchanger (13), the water in the refrigerant passage (13a) dissipates heat to the water in the water passage (13b). As a result, the refrigerant in the refrigerant passage (13a) condenses. The refrigerant that has dissipated heat in the water heat exchanger (13) is depressurized by the expansion valve (14) and then flows through the air heat exchanger (15). In the air heat exchanger (15), the refrigerant evaporates. The evaporated refrigerant is then drawn into the compressor (12).

[0063] The water in the water channel (13b) heated by the water heat exchanger (13) flows through the inlet pipe (31) and into the inlets (59) of the first heat exchanger (52a) and the second heat exchanger (52b). The water that flows into each inlet (59) is divided and flows into the first heat exchanger (52a) and the second heat exchanger (52b), and flows through the respective heat transfer tubes (53). After that, the water flows out from each outlet (60) into the outlet pipe (32). The water in the outlet pipe (32) flows back into the water heat exchanger (13) and is heated by the refrigerant channel (13a) of the water channel (13b).

[0064] During hot water supply operation, water from the storage tank (51) is supplied to the hot water supply target (T). When the water level in the storage tank (51) decreases, water is supplied to the storage tank (51) from the water source (S).

[0065] The water supplied to the storage tank (51) lowers the water temperature inside the storage tank (51). Therefore, the water in the storage tank (51) is heated by the heating operation.

[0066] -Water flow inside the storage tank- Next, we will explain the flow of fluid water in the storage tank (51).

[0067] As shown in Figure 3, in the first flow path (43), the fluid is heated by the first heat exchanger (52a) and the second heat exchanger (52b). As a result, an upward flow is formed in the first flow path (43).

[0068] In the second channel (44), the rise in fluid temperature is suppressed by heat dissipation from the side wall (56) of the storage tank (51). Therefore, the fluid in the second channel (44) is drawn into the first channel (43) via the bottom space (46) by the rising flow in the first channel (43). As a result, a downward flow is formed in the second channel (44). The rising flow in the first channel (43) flows into the upper space (47) of the storage tank (51). Subsequently, the rising flow is folded back downward from the top (55), forming a downward flow. This downward flow merges with the downward flow in the second channel (44).

[0069] The fluid near the center of the internal space (45) is at a lower temperature than the fluid in the first channel (43). Therefore, a portion of the upward flow in the first channel (43) flows towards the center of the second heat exchanger (52b). This flow then becomes a downward flow and flows out into the bottom space (46). The fluid in the bottom space (46) flows into the first channel (43). It is heated again within the first channel (43) and becomes an upward flow.

[0070] As described above, natural convection is formed inside the storage tank (51).

[0071] -Effects of the embodiment- In this embodiment, the hot water supply device (20) includes a storage tank (51) for storing fluid, a first partition (81a) disposed inside the storage tank (51) and extending in a direction along the side wall (56) of the storage tank (51), and a second partition (81b) disposed inside the first partition (81a) and extending in a direction along the side wall (56) of the storage tank (51). The first partition (81a) and the second partition (81b) are spaced apart from the bottom surface of the storage tank (51), and a first flow path (43) with an annular horizontal cross-section is formed between the first partition (81a) and the second partition (81b). Between the first partition (81a) and the inner surface of the side wall (56) of the storage tank (51), a second flow channel (44) with an annular horizontal cross-section is formed and is provided with heating sections (52a, 52b, 52d, 52e) for heating the fluid in the first flow channel (43).

[0072] The fluid in the first channel (43) is heated by the heating sections (52a, 52b). As a result, the fluid in the first channel (43) heats up and forms an upward flow, causing a pressure decrease at the bottom of the first channel. The fluids in the second channel (44), the internal space (45), and the bottom space (46) are drawn into the interior of the first channel (43) from the lower end. In this embodiment, natural convection can be promoted by utilizing the so-called chimney effect caused by the upward flow in the first channel (43). As a result, heat transfer from the heating sections (52a, 52b) to the fluid can be promoted.

[0073] In addition, the first channel (43) has a ring-shaped horizontal cross-section. Therefore, the cross-sectional area of ​​the first channel (43) can be reduced compared to, for example, a channel with a circular horizontal cross-section. This makes it possible to increase the flow velocity of the upward flow in the first channel (43).

[0074] In addition, since the second channel (44) is formed outside the first channel (43), the downflow flows through the second channel (44). Therefore, obstruction of the upflow in the first channel (43) by the downflow in the second channel (44) can be suppressed. As a result, the flow velocity of the upflow in the first channel (43) can be further increased.

[0075] In addition, as the upward flow in the first channel (43) increases, natural convection in the storage tank (51) can be promoted. As a result, the temperature of the fluid in the storage tank (51) can be quickly made uniform. This eliminates the need to install a separate stirring device. Consequently, the operation of the hot water supply device (20) is made easier, and manufacturing costs can be reduced.

[0076] In this embodiment, the first partition (81a) and the second partition (81b) also serve as a heat exchanger (52a, 52b) having spiral heat transfer tubes (53).

[0077] The fluid in the first channel (43) is heated from the lower end to the upper end of the first channel (43). Furthermore, the fluid in the first channel (43) is heated from the inner and outer sides of the first channel (43) by the first heat exchanger (52a) and the second heat exchanger (52b). This allows the upward flow in the first channel (43) to be heated while being straightened, and consequently, the flow velocity of the upward flow in the first channel (43) can be increased. As a result, heat transfer from the heat exchangers (52a, 52b) to the fluid can be promoted.

[0078] In this embodiment, the heat transfer tube (53) comprises a plurality of heat transfer sections (57, 57, ...) arranged in the vertical direction, and the first distance (D1) between adjacent heat transfer sections (57, 57) in the vertical direction is smaller than the second radial distance (D2) between the heat transfer tube (53) of the first heat exchanger (52a) and the heat transfer tube (53) of the second heat exchanger (52b).

[0079] This configuration prevents the fluid that has formed an upward flow in the first channel (43) from flowing between adjacent heat transfer sections (57, 57) in the vertical direction. This suppresses the attenuation of the fluid velocity in the upward flow and allows the fluid in the first channel (43) to be heated efficiently.

[0080] In addition, as the flow velocity of the upward flow of fluid in the first channel (43) increases, natural convection of the fluid can be promoted.

[0081] In addition, because the first distance (D1) is small, both heat exchangers (52a, 52b) can be made smaller in the vertical direction. This increases the volume of the upper space of the storage tank (51) and promotes natural convection in the upper space (47).

[0082] In addition, the number of turns in the spiral heat transfer tube (53) can be increased. Specifically, the number of heat transfer sections (57) can be increased. As a result, the contact area between the fluid in the first flow path (43) and the heat transfer tube (53) increases. This promotes heat exchange from the heat transfer tube (53) to the fluid.

[0083] In this embodiment, the inlet (59) of the heat transfer tube (53) is provided at the upper end of the heat transfer tube (53), and the outlet (60) of the heat transfer tube (53) is provided at the lower end of the heat transfer tube (53).

[0084] Specifically, the heat transfer medium heated by the water heat exchanger (13) passes through the inlet pipe (31) and flows into the inlet (59) of the first heat exchanger (52a) and the inlet (59) of the second heat exchanger (52b). The heat transfer medium flows downward through the heat transfer tubes (53) of the first heat exchanger (52a) and the second heat exchanger (52b), and flows out into the outlet pipe (32) from the outlets (60,60) at the lower ends of both heat transfer tubes (53,53). In other words, the heat transfer medium flows from the upper end to the lower end of each heat transfer tube (53). As a result, within the first flow path (43), the flow of the heat transfer medium is substantially counterflowing against the upward flow of the heated fluid. This allows the fluid within the first flow path (43) to be heated efficiently.

[0085] In this embodiment, the first partition (81a), the second partition (81b), and the heating sections (52a, 52b) are provided only in the lower part of the storage tank (51).

[0086] This ensures that a space is available above the storage tank (51) for the fluid, which has formed an upward flow through the heat transfer tubes (53), to flow through. Specifically, the upward flow in the first channel (43) flows into the upper space (47). The fluid then folds back at the top (55) to form a downward flow. This downward flow merges with the second channel (44). Thus, natural convection of the fluid can be promoted.

[0087] -Modified Embodiments- <Variation 1> As shown in Figure 4, in Modification 1 of this embodiment, a third heat exchanger (52c) is provided inside the storage tank (51).

[0088] The third heat exchanger (52c) has heat transfer tubes (53). The third heat exchanger (52c) is located inside the second heat exchanger (52b). In other words, three rows of heat transfer tubes (53, 53, 53) are provided inside the storage tank (51).

[0089] The radial distance between the outer end of the heat transfer tube (53) of the third heat exchanger (52c) and the inner end of the heat transfer tube (53) of the second heat exchanger (52b) is the same as the second distance (D2). A third flow path (48) is formed between the third heat exchanger (52c) and the second heat exchanger (52b).

[0090] The fluid in the first channel (43) is heated by the first heat exchanger (52a) and the second heat exchanger (52b). The fluid in the third channel (48) is heated by the second heat exchanger (52b) and the third heat exchanger (52c). As a result, an upward flow is formed in the first channel (43) and the third channel (48).

[0091] Thus, according to Modification 1, by arranging the heat transfer tubes (53, 53, 53) in multiple rows, the heat exchanger (52a, 52b, 52c) can be made smaller in the vertical direction. This increases the volume of the upper space (47) of the storage tank (51), and consequently promotes natural convection in the upper space (47).

[0092] In addition, the first channel (43) and the third channel (48) have annular horizontal cross-sections. The channel cross-sectional areas of the first channel (43) and the third channel (48) are relatively small. As a result, the flow velocity of the upward flow can be increased.

[0093] In addition, as the flow rate and velocity of the upward flow in the first channel (43) and the third channel (48) increase, the velocity of the downward flow in the second channel (44) and the internal space (45) can be increased. This promotes fluid convection.

[0094] <Variation 2> As shown in Figure 5, in the modified example 2 of this embodiment, a flow straightening plate (71) is provided inside the storage tank (51).

[0095] The rectifier plate (71) is located inside the storage tank (51) and is fixed above the heat transfer tubes (53) of the first heat exchanger (52a). The rectifier plate (71) guides the fluid rising in the first flow path (43) toward the center of the storage tank (51). Specifically, the rectifier plate (71) is a plate member formed in the shape of a frustoconical cylinder with an open top and bottom. The rectifier plate (71) is positioned to incline upward toward the radially inward direction of the storage tank (51) from near the upper end of the heat transfer tubes (53) of the first heat exchanger (52a). The opening center of the rectifier plate (71) coincides with the central axis of the heat transfer tubes (53).

[0096] Thus, according to Modification 2, the collision between the upward flow in the first channel (43) and the downward flow flowing from the upper space (47) near the upper end of the heat transfer tube (53) can be suppressed. This promotes natural convection of the fluid.

[0097] <Variation 3> As shown in Figure 6, in Modification 3 of this embodiment, the storage tank (51) is provided with a flow straightening plate (71) that is different in shape from the flow straightening plate (71) in Modification 2.

[0098] Specifically, the rectifier plate (71) is formed in the shape of a cylindrical inverted truncated cone. The rectifier plate (71) is formed to slope downward from above the heat transfer tubes (53) of the second heat exchanger (52b) toward the radially inward direction of the storage tank (51).

[0099] Thus, according to Modification 3, it is possible to suppress the collision of the upward flow in the first channel (43) and the downward flow flowing from the upper space (47) near the upper end of the heat transfer tube (53). This promotes natural convection of the fluid.

[0100] <Variation 4> As shown in Figure 7, in modified example 4, the first partition (81a) is a cylindrical first partition plate (82a). The second partition (81b) is a cylindrical second partition plate (82b). The heating section (52d) is a fourth heat exchanger (52d).

[0101] A first flow channel (43) is formed between the first partition plate (82a) and the second partition plate (82b). In other words, the first partition plate (82a) is positioned on the outer circumference side of the first flow channel (43), and the second partition plate (82b) is positioned on the inner circumference side of the first flow channel (43).

[0102] A second flow path (44) is formed between the outer surface of the first partition plate (82a) and the inner surface of the side wall (56) of the storage tank (51).

[0103] The fourth heat exchanger (52d) heats the fluid in the first flow path (43). The fourth heat exchanger (52d) is positioned between the first partition plate (82a) and the second partition plate (82b). The fourth heat exchanger (52d) has spiral heat transfer tubes (53) formed along the first partition plate (82a) and the second partition plate (82b).

[0104] The third distance (D3) is defined as the radial distance between the first partition plate (82a) and the heat transfer tube (53). Specifically, the third distance (D3) is the radial distance between the inner circumferential surface of the first partition plate (82a) and the outer circumferential end of the heat transfer tube (53) of the fourth heat exchanger (52d). The fourth distance (D4) is defined as the radial distance between the second partition plate (82b) and the heat transfer tube (53). Specifically, the fourth distance (D4) is the radial distance between the outer circumferential surface of the second partition plate (82b) and the inner circumferential end of the heat transfer tube (53) of the fourth heat exchanger (52d). The first distance (D1), which is the distance between vertically adjacent heat transfer sections (57, 57) of the fourth heat exchanger (52d), is smaller than the third distance (D3) and the fourth distance (D4).

[0105] In the first flow path (43), an outer flow path (43a) is formed between the first partition plate (82a) and the fourth heat exchanger (52d), and an inner flow path (43b) is formed between the second partition plate (82b) and the fourth heat exchanger (52d).

[0106] When the fluid in the first channel (43) is heated by the fourth heat exchanger (52d), an upward flow is formed in the outer channel (43a) and the inner channel (43b). As a result, the pressure in the lower part of the first channel (43) decreases. The fluids in the second channel (44), the internal space (45), and the bottom space (46) are drawn into the interior of the first channel (43).

[0107] Thus, according to Modification 4, natural convection can be promoted by utilizing the chimney effect caused by the upward flow in the outer channel (43a) and inner channel (43b) of the first channel (43). As a result, heat transfer from the fourth heat exchanger (52d) to the fluid can be promoted.

[0108] In addition, the first channel (43) is composed of an outer channel (43a) and an inner channel (43b). The outer channel (43a) and the inner channel (43b) have annular horizontal cross-sections. The channel cross-sectional areas of the outer channel (43a) and the inner channel (43b) are relatively small. As a result, the flow velocity of the upward flow can be increased.

[0109] In addition, the second channel (44) has a ring-shaped horizontal cross-section formed by the outer surface of the first partition plate (82a) and the inner surface of the side wall (56) of the storage tank (51). Since the second channel (44) is formed outside the first channel (43), a downward flow is formed in the second channel (44). Therefore, obstruction of the upward flow in the first channel (43) by the downward flow in the second channel (44) can be suppressed. As a result, the flow velocity of the upward flow in the first channel (43) can be further increased.

[0110] In addition, in the first flow path (43), it is possible to suppress the flow of the upward flow in the outer flow path (43a) and the upward flow in the inner flow path (43b) between adjacent heat transfer sections (57, 57) in the vertical direction. This suppresses the attenuation of the flow velocity of the upward flow in the outer flow path (43a) and the upward flow in the inner flow path (43b), and also allows the fluid in the first flow path (43) to be heated efficiently.

[0111] <Variation 5> As shown in Figure 8, in Modification 5 of this embodiment, the fourth heat exchanger (52d) and the fifth heat exchanger (52e) are arranged between the first partition plate (82a) and the second partition plate (82b) of Modification 4.

[0112] The fifth heat exchanger (52e) is a heating section (52e) that heats the fluid in the first flow path (43). The fifth heat exchanger (52e) is located on the outer circumference side of the fourth heat exchanger (52d) and on the inner circumference side of the first partition plate (82a). The fifth heat exchanger (52e) has a spiral heat transfer tube (53) formed to run along the fourth heat exchanger (52d) and the first partition plate (82a).

[0113] The radial distance between the first partition plate (82a) and the heat transfer tube (53) of the fifth heat exchanger (52e) is defined as the fifth distance (D5). Specifically, the fifth distance (D5) is the radial distance between the inner circumferential surface of the first partition plate (82a) and the outer circumferential end of the heat transfer tube (53) of the fifth heat exchanger (52e). The radial distance between the heat transfer tube (53) of the fourth heat exchanger (52d) and the heat transfer tube (53) of the fifth heat exchanger (52e) is defined as the sixth distance (D6). Specifically, the sixth distance (D6) is the radial distance between the outer circumferential end of the heat transfer tube (53) of the fourth heat exchanger (52d) and the outer circumferential end of the heat transfer tube (53) of the fifth heat exchanger (52e). The first distance (D1), which is the distance between vertically adjacent heat transfer sections (57, 57) of the fourth heat exchanger (52d) and the fifth heat exchanger (52e), is smaller than the fifth distance (D5) and the sixth distance (D6).

[0114] The first flow path (43) includes an outer flow path (43a) between the first partition plate (82a) and the fourth heat exchanger (52d), an intermediate flow path (43c) between the fourth heat exchanger (52d) and the fifth heat exchanger (52e), and an inner flow path (43b) between the second partition plate (82b) and the fifth heat exchanger (52e).

[0115] When the fluid in the first channel (43) is heated by the fourth heat exchanger (52d) and the fifth heat exchanger (52e), it rises in the outer channel (43a), the intermediate channel (43c), and the inner channel (43b), respectively. A flow is formed. As a result, the pressure decreases in the lower part of the first flow channel (43). The fluids in the second flow channel (44), the internal space (45), and the bottom space (46) are drawn into the interior of the first flow channel (43). In this way, in this embodiment, natural convection can be promoted by utilizing the chimney effect caused by the upward flow in the outer flow channel (43a), intermediate flow channel (43c), and inner flow channel (43b) of the first flow channel (43). As a result, heat transfer from the fourth heat exchanger (52d) and the fifth heat exchanger (52e) to the fluid can be promoted.

[0116] Thus, according to Modification 5, the fluid in the first channel (43) is heated by the fourth heat exchanger (52d) and the fifth heat exchanger (52e). Therefore, the fluid in the first channel (43) can be heated more efficiently.

[0117] In addition, the first channel (43) is composed of an outer channel (43a), an intermediate channel (43c), and an inner channel (43b). The outer channel (43a), intermediate channel (43c), and inner channel (43b) have annular horizontal cross-sections. The channel cross-sectional areas of the outer channel (43a), intermediate channel (43c), and inner channel (43b) are relatively small. As a result, the flow velocity of the upward flow can be further increased.

[0118] In addition, in the first flow path (43), the upward flow in the outer flow path (43a), the intermediate flow path (43c), and the inner flow path (43b) can be suppressed from flowing between the vertically adjacent heat transfer sections (57, 57) of the fourth heat exchanger (52d) and the fifth heat exchanger (52e). This suppresses the attenuation of the flow velocity of the upward flow in the first flow path (43) and allows the fluid in the first flow path (43) to be heated more efficiently.

[0119] Other embodiments The above embodiment may also have the following configuration.

[0120] As shown in Figure 9, in the heat transfer tubes (53) of the first heat exchanger (52a) and the second heat exchanger (52b) of the above embodiment, adjacent heat transfer sections (57, 57) in the vertical direction may be in contact with each other. Similarly, in the heat transfer tubes (53) of the third heat exchanger (52c), fourth heat exchanger (52d), and fifth heat exchanger (52e) of the above modified example, adjacent heat transfer sections (57, 57) in the vertical direction may be in contact with each other. This prevents the fluid from flowing between adjacent heat transfer sections (57, 57) in the vertical direction. Therefore, the attenuation of the flow velocity of the upward flow can be suppressed. In addition, the heat exchanger can be made smaller in the vertical direction. This allows for a wider upper space (47) to be secured, and consequently, natural convection of the fluid can be promoted. In addition, the number of turns of the spiral heat transfer tube (53) can be increased. This increases the area in contact with the heat transfer tube (53) by the upward flow. Therefore, heat exchange between the heat transfer tube (53) and the fluid can be promoted.

[0121] As shown in Figure 10, the heat transfer tubes (53) of each embodiment described above may be formed such that, in a cross-sectional view perpendicular to the axis of the heat transfer tube (53), the vertical length (H) from the lower end to the upper end of the heat transfer tube (53) is longer than the horizontal length (W) between the two side ends of the heat transfer tube (53). For example, the heat transfer tube (53) may be formed as an elliptical or flattened tube. This increases the contact area between the heat transfer tube (53) and the fluid rising inside the heat transfer tube (53) compared to, for example, a circular heat transfer tube. As a result, heat exchange between the heat transfer tube (53) and the fluid can be promoted. In addition, the resistance of the upward flow in the first flow path (43) can be reduced. As a result, the flow velocity of the upward flow can be increased, and consequently, natural convection in the storage tank (51) can be promoted.

[0122] In this embodiment, both the first partition (81a) and the second partition (81b) are composed of heat exchangers (52a, 52b). However, one of the first partition (81a) and the second partition (81b) may also serve as a heat exchanger (52a, 52b), while the other is a cylindrical partition plate. Here, the distance between adjacent heat transfer sections (57, 57) of one heat exchanger (52a, 52b) is defined as the first distance (D1). The distance between the heat transfer tubes (53) of one heat exchanger (52a, 52b) and the partition plate of the other is defined as the second distance (D2). In this case as well, it is preferable to make the first distance (D1) smaller than the second distance (D2).

[0123] In each of the above embodiments, the heat transfer medium flowing through the heating channel (30) and the heat transfer tube (53) may be a refrigerant or brine.

[0124] In each of the above embodiments, the storage tank (51) may be an open-type storage tank with an open top.

[0125] While embodiments and modifications have been described above, it will be understood that a variety of changes in form and details are possible without departing from the spirit and scope of the claims. Furthermore, these embodiments and modifications may be combined or substituted as appropriate, as long as they do not impair the functions of the subject matter of this disclosure. The terms "first," "second," "third," etc., used above are used to distinguish the phrases to which these terms are assigned, and do not limit the number or order of such phrases. [Industrial applicability]

[0126] As described above, this disclosure is useful for storage tank units. [Explanation of Symbols]

[0127] 20 Hot water supply system 30 Storage tanks 43 First channel 44 Second channel 50 Tank Units 51 Storage tank 52a 1st heat exchanger (heating section) 52b 2nd heat exchanger (heating section) 52d 4th heat exchanger (heating section) 52e 5th heat exchanger (heating section) 53 Heat transfer tubes 56 Side wall 57 Heat transfer section 59 Inlet 60 Outlet 71 Rectifier plate 81a First partition section 81b Second partition section 82a First partition plate 82b Second partition plate H is the vertical length. W: Horizontal length D1 1st distance D2 2nd distance D3 3rd distance D4 4th distance

Claims

1. A storage tank unit, A storage tank (51) for storing fluid, A first partition (81a) is located inside the storage tank (51) and extends in a direction along the side wall (56) of the storage tank (51), The first partition (81a) is positioned inside the second partition (81b) which extends in a direction along the side wall (56) of the storage tank (51), The first partition (81a) and the second partition (81b) are, It is positioned spaced apart from the bottom surface of the aforementioned storage tank (51), Between the first partition (81a) and the second partition (81b), a first flow channel (43) having an annular horizontal cross-section is formed. Between the first partition (81a) and the inner surface of the side wall (56) of the storage tank (51), a second flow channel (44) with an annular horizontal cross-section is formed. The device includes heating sections (52a, 52b, 52d, 52e) for heating the fluid in the first flow path (43), As the heating section (52a, 52b, 52d, 52e) heats the fluid, an upward flow is formed in the first flow path (43) and a downward flow is formed in the second flow path (44). The heating section (52a, 52b, 52d, 52e) is a heat exchanger (52a, 52b) having spiral heat transfer tubes (53), The first partition (81a) and the second partition (81b) also serve as the heat exchanger (52a, 52b), The heat transfer tube (53) comprises a plurality of heat transfer sections (57, 57, ...) arranged in the vertical direction. There is a gap between the heat transfer sections (57, 57) that are adjacent to each other in the vertical direction. The first distance (D1) between adjacent heat transfer sections (57, 57) in the vertical direction is smaller than the second radial distance (D2) between the first partition section (81a) and the second partition section (81b). A storage tank unit characterized by the following features.

2. In claim 1, The inlet (59) of the heat transfer tube (53) is provided at the upper end of the heat transfer tube (53). The outlet (60) of the heat transfer tube (53) is provided at the lower end of the heat transfer tube (53). A storage tank unit characterized by the following features.

3. In claim 1 or 2, A storage tank unit characterized in that, in a cross-sectional view perpendicular to the axis of the heat transfer tube (53), the vertical length (H) from the lower end to the upper end of the heat transfer tube (53) is longer than the horizontal length (W) between the two side ends of the heat transfer tube (53).

4. In any one of claims 1 to 3, The system includes a flow straightening plate (71) positioned above the first flow path (43) that guides the fluid rising in the first flow path (43) toward the center of the storage tank (51). A storage tank unit characterized by the following features.

5. In any one of claims 1 to 4, A storage tank unit characterized in that the first partition (81a), the second partition (81b), and the heating sections (52a, 52b, 52d, 52e) are provided only in the lower part of the storage tank (51).

6. A hot water supply system (20) equipped with a tank unit for storing water, A storage tank unit characterized by comprising one of the storage tank units (50) according to any one of claims 1 to 5.

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