STORAGE TYPE HOT WATER SUPPLYING APPARATUS

Abstract

A storage type hot water supplying apparatus according to the present disclosure includes a hot water storage tank, and a condenser located at the hot water storage tank, the condenser including a helical refrigerant pipe centered on a vertical line. The condenser has an upper part and a lower part located lower than the upper part. A vertical length of a vertical cross-sectional shape of the refrigerant pipe in the lower part of the condenser is shorter than a vertical length of a vertical cross-sectional shape of the refrigerant pipe in the upper part of the condenser. A pitch of a helix formed by the refrigerant pipe in the lower part of the condenser may be smaller than a pitch of a helix formed by the refrigerant pipe in the upper part of the condenser.

Description

TECHNICAL FIELD

The present disclosure relates to a storage type hot water supplying apparatus.

BACKGROUND ART

PTL 1 described below discloses a water heater including a water tank with a wall part formed from a material having heat transfer properties, a pipe mounted on the outer peripheral portion of the wall part of the water tank to carry refrigerant, a heat-transfer material coextensive with the length of the pipe and allowing the pipe to be in heat-transfer contact with the wall part of the water tank, and at least one material layer tightly wrapped about the wall part of the water tank and the pipe.

CITATION LIST

Patent Literature

• • [PTL 1] JP 2006-521528 T

SUMMARY OF THE INVENTION

Problem to be Solved by the Invention

The water heater disclosed in PTL 1 has a problem that when liquid refrigerant collects in a refrigerant pipe on the water tank, that is, in the refrigerant pipe in the lower part of the hot water storage tank, the lower part of the hot water storage tank has a large region at a low water temperature and hence, it is difficult to increase the amount of heat storage of the hot water storage tank.

The present disclosure has been made to solve the above-described problem, and it is an object of the present disclosure to provide a storage type hot water supplying apparatus that has an advantage in increasing the amount of heat storage of the hot water storage tank.

Solution to Problem

A storage type hot water supplying apparatus according to the present disclosure includes: a hot water storage tank; and a condenser located at the hot water storage tank. The condenser includes a helical refrigerant pipe centered on a vertical line. The condenser has an upper part and a lower part located lower than the upper part. A vertical length of a vertical cross-sectional shape of the refrigerant pipe in the lower part of the condenser is shorter than a vertical length of a vertical cross-sectional shape of the refrigerant pipe in the upper part of the condenser.

Advantageous Effects of the Invention

According to the present disclosure, it is possible to provide a storage type hot water supplying apparatus that has an advantage in increasing the amount of heat storage of a hot water storage tank.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram showing a storage type hot water supplying apparatus according to an embodiment 1.

FIG. 2 is a graph showing distribution of temperature along a vertical direction within a hot water storage tank during a hot water storage operation.

FIG. 3 is a schematic cross-sectional side view illustrating distribution of water temperature in the hot water storage tank.

FIG. 4 is a cross-sectional view showing an example of a vertical cross-sectional shape of a refrigerant pipe of a condenser of the storage type hot water supplying apparatus according to the embodiment 1.

FIG. 5 is a cross-sectional view showing another example of a vertical cross-sectional shape of the refrigerant pipe of the condenser of the storage type hot water supplying apparatus according to the embodiment 1.

FIG. 6 is a cross-sectional view showing another example of a vertical cross-sectional shape of the refrigerant pipe of the condenser of the storage type hot water supplying apparatus according to the embodiment 1.

FIG. 7 is a schematic cross-sectional side view illustrating a storage type hot water supplying apparatus according to a embodiment 2.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments will be described with reference to drawings. In the respective drawings, the identical or corresponding elements are given the same reference symbols, and the description of such elements will be simplified or omitted. In the description made hereinafter, in principle, the term “water” or “hot water” means liquid water, and may include cold water and boiling water. The configurations shown in the embodiments described below merely show examples of the technical concept of the present disclosure, and may be combined with other known techniques, or a plurality of technical concepts described in the present disclosure may be combined. Further, some of the configurations may be omitted or changed without departing from the gist of the present disclosure.

Embodiment 1

FIG. 1 is a diagram showing a storage type hot water supplying apparatus 1 according to an embodiment 1. As shown in FIG. 1, the storage type hot water supplying apparatus 1 according to the embodiment 1 includes a heat source machine 2 and a tank unit 3. The heat source machine 2 is disposed outdoors. The tank unit 3 may be disposed outdoors, or may be disposed in the room. The heat source machine 2 and the tank unit 3 are connected to each other via an extension pipe 4, an extension pipe 5, and an electric cable (not shown in the drawing). The storage type hot water supplying apparatus 1 may be a household hot water supplying apparatus or a commercial hot water supplying apparatus.

A hot water storage tank 6 is provided in a housing of the tank unit 3. The hot water storage tank 6 in the present embodiment has a cylindrical outer shape. When the tank unit 3 is installed in an installation location, the center axis of the hot water storage tank 6 is substantially parallel to the vertical line. In the present disclosure, the description will be made assuming that the center axis of the hot water storage tank 6 is parallel to the vertical line. The hot water storage tank 6 may be made of metal, such as stainless steel, for example. A heat insulating material (not shown in the drawing) is provided in the housing of the tank unit 3, the heat insulating material covering a condenser 17, which will be described later, and the hot water storage tank 6.

A feed water inlet 7 is located at the lower part of the hot water storage tank 6. A hot water outlet 8 is located at the upper part of the hot water storage tank 6. A feed water pipe 9 is connected to the feed water inlet 7. A hot water supply pipe 10 is connected to the hot water outlet 8. The downstream end of the hot water supply pipe 10 is connected to a hot water supply terminal (not shown in the drawing) installed in the building. The hot water supply terminal may include, for example, at least one of a faucet, a shower, and a bathtub.

Water supplied from a water source, such as a water supply, for example, flows into the lower part of the hot water storage tank 6 through the feed water pipe 9, so that the inside of the hot water storage tank 6 is always maintained in a state of being fully filled with water. In performing a hot water supply action that supplies hot water to the hot water supply terminal, hot water in the hot water storage tank 6 flows out to the hot water supply pipe 10 from the hot water outlet 8 due to a water pressure from the feed water pipe 9. With such outflow of hot water, the same amount of water flows into the lower part of the hot water storage tank 6 from the feed water pipe 9 through the feed water inlet 7. As described above, the hot water supply action is an action that allows hot water in the hot water storage tank 6 to flow out from the hot water outlet 8, and that allows water to flow into the hot water storage tank 6 from the feed water inlet 7.

The heat source machine 2 is provided with an evaporator 11, a compressor 12, an expansion valve 13, and control circuitry 14, the evaporator 11 evaporating refrigerant, the compressor 12 compressing the refrigerant flowing out from the evaporator 11. The evaporator 11 in the present embodiment evaporates refrigerant by exchanging heat between outdoor air and refrigerant. In the example shown in the drawing, the heat source machine 2 further includes a blower 15 for sending outdoor air to the evaporator 11.

The storage type hot water supplying apparatus 1 further includes a condenser 17 located at the hot water storage tank 6. The condenser 17 condenses refrigerant by exchanging heat between refrigerant compressed by the compressor 12 and water in the hot water storage tank 6. The condenser 17 includes a refrigerant pipe 18 centered on the vertical line, the refrigerant pipe 18 having a helical shape or a coil shape. In the present embodiment, the refrigerant pipe 18 is wound around the hot water storage tank 6 in a helical shape or a coil shape at a position between the heat insulating material (not shown in the drawing) and the surface of the hot water storage tank 6, the heat insulating material covering the outer periphery of the hot water storage tank 6. The refrigerant pipe 18 is in heat conductive contact with the outer wall of the hot water storage tank 6. The heat of refrigerant flowing through the refrigerant pipe 18 is transferred to the peripheral wall of the hot water storage tank 6. The heat transferred to the peripheral wall of the hot water storage tank 6 is transferred to water in the hot water storage tank 6, so that the water in the hot water storage tank 6 is heated. The refrigerant pipe 18 is disposed such that the position of the refrigerant pipe 18 gradually descends from the upstream side toward the downstream side of the refrigerant pipe 18 while winding around the outer periphery of the hot water storage tank 6. The center axis of the helix or coil formed by the refrigerant pipe 18 aligns with the center axis of the hot water storage tank 6.

The refrigerant pipe 18 may be made of metal. The material of the refrigerant pipe 18 may be, for example, copper, copper alloy, aluminum, or aluminum alloy.

The condenser 17 has an upper part 17A and a lower part 17B. The lower part 17B is located lower than the upper part 17A. A configuration is adopted in which refrigerant flows from the refrigerant pipe 18 in the upper part 17A of the condenser 17 to the refrigerant pipe 18 in the lower part 17B of the condenser 17. A vertical dimension LA of the upper part 17A of the condenser 17 is a distance from the upper end of the upper part 17A to the lower end of the upper part 17A in the vertical direction. A vertical dimension LB of the lower part 17B of the condenser 17 is a distance from the upper end of the lower part 17B to the lower end of the lower part 17B in the vertical direction. The vertical dimension LA of the upper part 17A of the condenser 17 is larger than the vertical dimension LB of the lower part 17B of the condenser 17.

The extension pipe 4 forms a refrigerant passage that couples the outlet of the compressor 12 to the inlet of the upper part 17A of the condenser 17. The extension pipe 5 forms a refrigerant passage that couples the outlet of the lower part 17B of the condenser 17 to the inlet of the expansion valve 13. Refrigerant compressed by the compressor 12 moves from the heat source machine 2 to the tank unit 3 through the extension pipe 4, and flows into the inlet of the upper part 17A of the condenser 17. After passing through the refrigerant pipe 18 in the upper part 17A of the condenser 17, the refrigerant flows into the refrigerant pipe 18 in the lower part 17B of the condenser 17. After flowing out from the outlet of the lower part 17B of the condenser 17, the refrigerant returns to the heat source machine 2 from the tank unit 3 through the extension pipe 5, and then flows into the expansion valve 13.

The expansion valve 13 expands refrigerant flowing out from the condenser 17. The refrigerant is reduced in pressure when passing through the expansion valve 13. The expansion valve 13 may be a linear expansion valve the opening degree of which can be continuously controlled. After passing through the expansion valve 13, the refrigerant flows into the evaporator 11. The refrigerant evaporated by the evaporator 11 flows into the compressor 12, and is compressed.

The control circuitry 14 controls a hot water storage operation. The hot water storage operation is an operation that supplies high-temperature and high-pressure refrigerant to the condenser 17 from the compressor 12 so as to heat water in the hot water storage tank 6 with the high-temperature and high-pressure refrigerant flowing through the refrigerant pipe 18 of the condenser 17. The control circuitry 14 may include at least one processor and at least one memory. At least one processor may achieve the respective functions of the control circuitry 14 by reading and executing a program stored in at least one memory. The control circuitry 14 may include at least one dedicated hardware. The control circuitry 14 may be, for example, single circuitry, composite circuitry, a programmed processor, a parallel-programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination of the above.

In the example shown in the drawing, the control circuitry 14 is disposed in the heat source machine 2. However, as a modification, the control circuitry 14 may be disposed in the tank unit 3. The functions of the control circuitry 14 may be achieved by a controller disposed in the heat source machine 2 and a controller disposed in the tank unit 3 mutually communicating to cooperate with each other. At least some functions of the control circuitry 14 may be achieved by a cloud server connected via a network, such as the internet.

During the hot water storage operation, the control circuitry 14 controls the action of the compressor 12 and the opening degree of the expansion valve 13. The action speed of the compressor 12 may be variable. The control circuitry 14 may variably control the action speed of the compressor 12 by allowing the operating frequency of an electric motor included in the compressor 12 to be variably controlled by inverter control. A higher operating frequency of the compressor 12 causes a higher action speed of the compressor 12. A higher action speed of the compressor 12 causes a larger circulation amount of refrigerant, leading to a higher heating capacity. A heating capacity is the quantity of heat applied per unit time period to water in the hot water storage tank 6 from refrigerant, and the unit of the heating capacity is the watt.

The control circuitry 14 may communicate with a user interface 19 via wired communication or wireless communication. The user interface 19 may be, for example, a remote control device installed on the wall of the room. Alternatively, the user interface 19 may be, for example, a mobile device, such as a smartphone.

Hereinafter, the temperature of water in the hot water storage tank 6 may be referred to as “tank water temperature”. FIG. 2 is a graph showing distribution of temperature along the vertical direction within the hot water storage tank 6 during the hot water storage operation. The vertical axis in FIG. 2 shows the vertical position in the hot water storage tank 6 as expressed by the volume of water from the lowermost part of the hot water storage tank 6. In FIG. 2. “distribution of water temperature” indicates distribution of tank water temperature. In FIG. 2. “tank wall surface temperature” indicates distribution of temperature of the wall surface of the hot water storage tank 6. In FIG. 2. “refrigerant temperature” indicates distribution of temperature of refrigerant in the condenser 17.

In the graph shown in FIG. 2, a refrigerant temperature is substantially constant along the vertical direction in a vertical region, and the refrigerant temperature in the vertical region corresponds to the condensation temperature. In this vertical region, refrigerant is in a gas-liquid two-phase state. Refrigerant at the inlet of the condenser 17 has a temperature higher than the condensation temperature, that is, is in a superheated gas state. The difference between the temperature of refrigerant in a superheated gas state and the condensation temperature is referred to as the degree of superheat. In the upper part 17A of the condenser 17, refrigerant is in a superheated gas state in some regions close to the inlet, and refrigerant is in a gas-liquid two-phase state in other regions.

In the graph shown in FIG. 2, a vertical region SC in which a refrigerant temperature is lower than the condensation temperature corresponds to the lower part 17B of the condenser 17. In the vertical region SC, that is, in the lower part 17B of the condenser 17, refrigerant is condensed to be in a liquid phase state. That is, the vertical region SC, corresponding to the lower part 17B of the condenser 17, is filled with liquid refrigerant being refrigerant in a liquid phase. The temperature of liquid refrigerant is lower than the condensation temperature. The difference between the condensation temperature and the temperature of liquid refrigerant is referred to as “degree of subcooling”. In general, the degree of subcooling is also referred to as “subcooling”. Liquid refrigerant at a temperature lower than the condensation temperature flows out from the condenser 17. Such liquid refrigerant flows into the expansion valve 13 through the extension pipe 5.

In the vertical region in which a refrigerant temperature is equal to the condensation temperature, the tank wall surface temperature is substantially constant along the vertical direction at a temperature slightly lower than the condensation temperature. In a vertical region in which refrigerant is in a superheated gas state, the tank wall surface temperature is higher than the tank wall surface temperature in the vertical region in which the refrigerant temperature is equal to the condensation temperature. In a vertical region above the vertical region in which refrigerant is in a superheated gas state, the tank wall surface temperature gradually decreases toward the upper side, and reaches a temperature equal to the tank water temperature. The reason is that, in a vertical region above the upper end of the condenser 17, the wall of the hot water storage tank 6 is not heated.

Heat of refrigerant passing through the refrigerant pipe 18 of the condenser 17 is transferred to the wall of the hot water storage tank 6, and is further transferred to water that is in contact with the inner wall of the hot water storage tank 6. When the water that is in contact with the inner wall of the hot water storage tank 6 is heated, the density of the water decreases and hence, the water gains buoyancy to move upward in the hot water storage tank 6. As a result, spontaneous convection heat transfer occurs between the water and the inner wall of the hot water storage tank 6. Further, spontaneous convection is generated in the hot water storage tank 6. Water in the hot water storage tank 6 is stirred by such spontaneous convection and hence, as shown in distribution of water temperature in FIG. 2, the tank water temperature achieves a substantially uniform distribution along the vertical direction in a region ranging from the vertical region in which the refrigerant temperature is equal to the condensation temperature to the uppermost part of the hot water storage tank 6. That is, the tank water temperature achieves a substantially uniform distribution along the vertical direction in the region ranging from the boundary between the upper part 17A and the lower part 17B of the condenser 17 to the uppermost part of the hot water storage tank 6.

In the vertical region SC corresponding to the lower part 17B of the condenser 17, the refrigerant temperature is lower than the condensation temperature and hence, the tank wall surface temperature is also low. Thus, the tank water temperature is also low. As a result, as shown in distribution of water temperature in FIG. 2, in a region ranging from the boundary between the upper part 17A and the lower part 17B of the condenser 17 to the lowermost part of the hot water storage tank 6, the tank water temperature is lower than the tank water temperature in the vertical region located above such a region.

FIG. 3 is a schematic cross-sectional side view illustrating distribution of water temperature in the hot water storage tank 6. A diagram on the right side in FIG. 3 corresponds to the storage type hot water supplying apparatus 1 according to the embodiment 1. A diagram on the left side in FIG. 3 corresponds to a comparison example. As shown in the diagram on the right side in FIG. 3, in the present embodiment, a vertical length V of the vertical cross-sectional shape of the refrigerant pipe 18 in the lower part 17B of the condenser 17 is shorter than a vertical length V of the vertical cross-sectional shape of the refrigerant pipe 18 in the upper part 17A of the condenser 17. In contrast, in the comparison example, a vertical length V of the vertical cross-sectional shape of the refrigerant pipe 18 is constant across the entire condenser 17. The vertical cross-sectional shape of the refrigerant pipe 18 is a shape of the refrigerant pipe 18 in cross section taken along a plane including the vertical line forming the center of the helix formed by the refrigerant pipe 18. In other words, the vertical cross-sectional shape of the refrigerant pipe 18 is the shape of the refrigerant pipe 18 in cross section taken along a plane including the center axis of the hot water storage tank 6. The vertical length V corresponds to a distance from the uppermost part to the lowermost part of the vertical cross-sectional shape in the vertical direction.

During the hot water storage operation, the control circuitry 14 controls the action of the compressor 12 and the action of the expansion valve 13 such that the refrigerant pipe 18 in the lower part 17B of the condenser 17 is filled with liquid refrigerant, and the refrigerant pipe 18 in the upper part 17A of the condenser 17 is filled with refrigerant in a superheated gas state or refrigerant in a gas-liquid two-phase state. When the refrigerant pipe 18 in the lower part 17B of the condenser 17 is filled with liquid refrigerant, it is possible to surely prevent a situation in which refrigerant at the inlet of the expansion valve 13 is in a gas-liquid two-phase state and hence, ease of control of the heat source machine 2 is enhanced.

As described with reference to FIG. 2, the vertical region SC corresponding to the lower part 17B of the condenser 17 has a low tank water temperature, the refrigerant pipe 18 in the lower part 17B of the condenser 17 being filled with liquid refrigerant. Therefore, to increase the amount of heat storage of the hot water storage tank 6, a configuration having a smaller vertical region SC is more advantageous, the vertical region SC corresponding to the lower part 17B of the condenser 17. In the present embodiment, the vertical length V of the vertical cross-sectional shape of the refrigerant pipe 18 in the lower part 17B of the condenser 17 is shorter than the vertical length V of the vertical cross-sectional shape of the refrigerant pipe 18 in the upper part 17A of the condenser 17 and hence, the present embodiment has an advantage in reducing the vertical dimension LB of the lower part 17B of the condenser 17. As a result, the hot water storage tank 6 has a small vertical region in which the tank water temperature is low and hence, it is possible to increase the amount of heat storage of the hot water storage tank 6.

In contrast, in the comparison example shown in the diagram on the left side in FIG. 3, a vertical dimension LC of the lower part of the condenser 17 is larger than that in the present embodiment, the refrigerant pipe 18 in the lower part of the condenser 17 being filled with liquid refrigerant. Therefore, the hot water storage tank 6 has a larger vertical region in which the tank water temperature is low than that in the present embodiment and hence, the amount of heat storage of the hot water storage tank 6 is smaller than that in the present embodiment.

FIG. 3 is a schematic view, and is illustrated in a simplified manner. In FIG. 3, the size of the vertical cross-sectional shape of the refrigerant pipe 18 is drawn in an exaggerated manner compared with the size of the hot water storage tank 6. In FIG. 3, the number of turns of the helix formed by the refrigerant pipe 18 in the upper part 17A of the condenser 17 is two. However, in practice, the number of turns of the helix formed by the refrigerant pipe 18 in the upper part 17A of the condenser 17 may be three or more. In FIG. 3, the number of turns of the helix formed by the refrigerant pipe 18 in the lower part 17B of the condenser 17 is two. However, in practice, the number of turns of the helix formed by the refrigerant pipe 18 in the lower part 17B of the condenser 17 may be three or more.

In the present embodiment, the vertical length V of the vertical cross-sectional shape of the refrigerant pipe 18 in the upper part 17A of the condenser 17 is preferably 1.1 times or more, and is more preferably 1.3 times or more the vertical length V of the vertical cross-sectional shape of the refrigerant pipe 18 in the lower part 17B of the condenser 17. The vertical length V of the vertical cross-sectional shape of the refrigerant pipe 18 in the upper part 17A of the condenser 17 is preferably 3 times or less, and is more preferably 2.5 times or less the vertical length V of the vertical cross-sectional shape of the refrigerant pipe 18 in the lower part 17B of the condenser 17. A configuration that satisfies the above-mentioned relationships has an advantage in increasing the amount of heat storage of the hot water storage tank 6.

In the present embodiment, the vertical dimension LA of the upper part 17A of the condenser 17 is preferably 1.2 times or more, and is more preferably 1.5 times or more the vertical dimension LB of the lower part 17B of the condenser 17. The vertical dimension LA of the upper part 17A of the condenser 17 is preferably 20 times or less, and is more preferably 15 times or less the vertical dimension LB of the lower part 17B of the condenser 17. A configuration that satisfies the above-mentioned relationships has an advantage in increasing the amount of heat storage of the hot water storage tank 6.

FIG. 4 is a cross-sectional view showing an example of the vertical cross-sectional shape of the refrigerant pipe 18 of the condenser 17 of the storage type hot water supplying apparatus 1 according to the embodiment 1. The vertical cross-sectional shape of the refrigerant pipe 18 shown in FIG. 4 is a cocoon shape. The vertical length V of the vertical cross-sectional shape of the refrigerant pipe 18 shown in FIG. 4 is longer than a horizontal length H of the vertical cross-sectional shape. The horizontal length H corresponds to a distance from the left end to the right end of the vertical cross-sectional shape in the horizontal direction. The cocoon-shaped refrigerant pipe 18 shown in FIG. 4 includes a recessed portion 18a formed between a bulge at the upper portion of the vertical cross-sectional shape and a bulge at the lower portion of the vertical cross-sectional shape. As in the example shown in FIG. 4, the refrigerant pipe 18 may include a flat part 18b at a portion that is joined to the wall surface of the hot water storage tank 6. The flat part 18b is where the pipe wall of the refrigerant pipe 18 forms a flat region. When the refrigerant pipe 18 includes the flat part 18b, the contact area between the wall surface of the hot water storage tank 6 and the refrigerant pipe 18 is increased, and contact thermal resistance is reduced and hence, it is possible to increase the amount of heat exchange. When the amount of heat exchange of the condenser 17 increases, the discharge pressure of the compressor 12 can be reduced and hence, it is possible to reduce power consumption of the storage type hot water supplying apparatus 1. As in the example shown in FIG. 4, a heat-conductive material 20 may be provided between the wall surface of the hot water storage tank 6 and the refrigerant pipe 18. The heat-conductive material 20 may be, for example, a solder, a brazing filler metal, or weld metal.

Instead of the refrigerant pipe 18 having the cocoon-shaped vertical cross-sectional shape shown in FIG. 4, a refrigerant pipe 18 may be used that has an elliptical vertical cross-sectional shape having no recessed portion 18a.

FIG. 5 is a cross-sectional view showing another example of the vertical cross-sectional shape of the refrigerant pipe 18 of the condenser 17 of the storage type hot water supplying apparatus 1 according to the embodiment 1. Points that make the example shown in FIG. 5 different from the example shown in FIG. 4 will be described. The vertical cross-sectional shape of the refrigerant pipe 18 shown in FIG. 5 is a D shape. The refrigerant pipe 18 having such a D-shaped vertical cross-sectional shape has one bulge on the side opposite to the flat part 18b.

Hereinafter, the value of V/H, obtained by dividing the vertical length V of the vertical cross-sectional shape of the refrigerant pipe 18 by the horizontal length H of the vertical cross-sectional shape, is referred to as “aspect ratio”. The aspect ratio V/H of the refrigerant pipe 18 having a D-shaped vertical cross-sectional shape shown in FIG. 5 is smaller than the aspect ratio V/H of the refrigerant pipe 18 having a cocoon-shaped vertical cross-sectional shape shown in FIG. 4.

FIG. 6 is a cross-sectional view showing another example of the vertical cross-sectional shape of the refrigerant pipe 18 of the condenser 17 of the storage type hot water supplying apparatus 1 according to the embodiment 1. Points that make the example shown in FIG. 6 different from the example shown in FIG. 4 will be described. The vertical cross-sectional shape of the refrigerant pipe 18 shown in FIG. 6 is a C shape. The refrigerant pipe 18 having such a C-shaped vertical cross-sectional shape includes, on the side opposite to the flat part 18b, an upper protruding part 18c, a lower protruding part 18d, and a groove part 18e, the upper protruding part 18c protruding outward in the radial direction of the hot water storage tank 6, the lower protruding part 18d protruding outward in the radial direction of the hot water storage tank 6, the groove part 18e formed between the upper protruding part 18c and the lower protruding part 18d. The groove part 18e is located below the upper protruding part 18c. The lower protruding part 18d is located below the groove part 18e. The depth of the groove part 18e is larger than the depth of the recessed portion 18a of the refrigerant pipe 18 having a cocoon-shaped vertical cross-sectional shape shown in FIG. 4. The aspect ratio V/H of the refrigerant pipe 18 having a C-shaped vertical cross-sectional shape shown in FIG. 6 is smaller than the aspect ratio V/H of the refrigerant pipe 18 having a cocoon-shaped vertical cross-sectional shape shown in FIG. 4.

Although the illustration is omitted, the vertical cross-sectional shape of the refrigerant pipe 18 of the condenser 17 of the storage type hot water supplying apparatus 1 according to the embodiment 1 may be a circular shape.

In the present embodiment, it is desirable that the aspect ratio V/H of the refrigerant pipe 18 in the lower part 17B of the condenser 17 be smaller than the aspect ratio V/H of the refrigerant pipe 18 in the upper part 17A of the condenser 17. With such a configuration, it is possible to easily achieve a configuration in which the vertical length V of the vertical cross-sectional shape of the refrigerant pipe 18 in the lower part 17B of the condenser 17 is shorter than the vertical length V of the vertical cross-sectional shape of the refrigerant pipe 18 in the upper part 17A of the condenser 17.

In the present embodiment, the vertical cross-sectional shape of the refrigerant pipe 18 in the upper part 17A of the condenser 17 may be a cocoon shape described above or an elliptical shape, for example. When the vertical cross-sectional shape of the refrigerant pipe 18 in the upper part 17A of the condenser 17 is a cocoon shape or an elliptical shape, the contact area between the wall surface of the hot water storage tank 6 and the refrigerant pipe 18 increases and hence, the amount of heat exchange of the condenser 17 is increased. A cocoon-shaped or elliptical vertical cross-sectional shape has a relatively small cross-sectional area and hence, the upper part 17A of the condenser 17 has a relatively small inner volume. As a result, it is possible to reduce the required amount of refrigerant for the refrigerant circuit as a whole.

The vertical cross-sectional shape of the refrigerant pipe 18 in the lower part 17B of the condenser 17 may be, for example, a D shape described above, a circular shape, or a C shape. When the vertical cross-sectional shape of the refrigerant pipe 18 in the lower part 17B of the condenser 17 is a D shape, a circular shape, or a C shape, the aspect ratio V/H is relatively small and hence, it is possible to easily reduce the vertical length V of the vertical cross-sectional shape.

Further, when the vertical cross-sectional shape of the refrigerant pipe 18 in the lower part 17B of the condenser 17 is a D shape or a C shape, the refrigerant pipe 18 has a smaller cross-sectional area than a refrigerant pipe 18 having a circular cross-sectional shape and hence, the lower part 17B of the condenser 17 has a relatively small inner volume. As a result, it is possible to reduce the required amount of refrigerant for the refrigerant circuit as a whole.

A configuration may be adopted in which the vertical cross-sectional shape of the refrigerant pipe 18 in the upper part 17A of the condenser 17 differs from the vertical cross-sectional shape of the refrigerant pipe 18 in the lower part 17B of the condenser 17. For example, a configuration may be adopted in which the vertical cross-sectional shape of the refrigerant pipe 18 in the upper part 17A of the condenser 17 is a cocoon shape or an elliptical shape, and the vertical cross-sectional shape of the refrigerant pipe 18 in the lower part 17B of the condenser 17 is a D shape, a circular shape, or a C shape.

A configuration may be adopted in which the refrigerant pipe 18 in the upper part 17A of the condenser 17 and the refrigerant pipe 18 in the lower part 17B of the condenser 17 have the same vertical cross-sectional shape, but have different aspect ratios V/H. For example, a configuration may be adopted in which each of the vertical cross-sectional shape of the refrigerant pipe 18 in the upper part 17A of the condenser 17 and the vertical cross-sectional shape of the refrigerant pipe 18 in the lower part 17B of the condenser 17 is a D shape, and the aspect ratio V/H of the refrigerant pipe 18 in the lower part 17B of the condenser 17 is smaller than the aspect ratio V/H of the refrigerant pipe 18 in the upper part 17A of the condenser 17.

In the present embodiment, it is preferable that the number of turns of the helix formed by the refrigerant pipe 18 in the upper part 17A of the condenser 17 be larger than the number of turns of the helix formed by the refrigerant pipe 18 in the lower part 17B of the condenser 17. When the helix formed by the refrigerant pipe 18 in the upper part 17A, in which refrigerant has a high temperature, has a relatively large number of turns, and when the helix formed by the refrigerant pipe 18 in the lower part 17B, in which refrigerant has a relatively low temperature, has a relatively low number of turns, this configuration has an advantage in increasing the amount of heat storage of the hot water storage tank 6.

Embodiment 2

Next, an embodiment 2 will be described with reference to FIG. 7. However, the description will be mainly made for points that make the embodiment 2 different from the above-described embodiment 1, and the repeated description will be simplified or omitted. Further, elements identical or corresponding to the above-described elements are given the same reference symbols.

FIG. 7 is a schematic cross-sectional side view illustrating a storage type hot water supplying apparatus 1 according to the embodiment 2. A diagram on the right side in FIG. 7 corresponds to the storage type hot water supplying apparatus 1 according to the embodiment 2. As shown in the diagram on the right side in FIG. 7, in the storage type hot water supplying apparatus 1 according to the embodiment 2, a pitch P of the helix formed by a refrigerant pipe 18 in a lower part 17B of a condenser 17 is smaller than a pitch P of the helix formed by a refrigerant pipe 18 in an upper part 17A of the condenser 17. In cross section taken along a plane including the center axis of a hot water storage tank 6, the pitch P of the helix formed by the refrigerant pipe 18 corresponds to a distance between the centers of two refrigerant pipes 18 disposed adjacent to each other.

A diagram on the left side in FIG. 7 shows an example in which the pitch P of the helix formed by the refrigerant pipe 18 in the lower part 17B of the condenser 17 is equal to the pitch P of the helix formed by the refrigerant pipe 18 in the upper part 17A of the condenser 17. Compared with this example, the pitch P of the helix formed by the refrigerant pipe 18 in the lower part 17B of the condenser 17 is smaller than the pitch P of the helix formed by the refrigerant pipe 18 in the upper part 17A of the condenser 17 in the embodiment 2 and hence, it is possible to further reduce the vertical dimension LB of the lower part 17B of the condenser 17 in the embodiment 2. As a result, the hot water storage tank 6 has an even smaller vertical region in which the tank water temperature is low and hence, it is possible to further increase the amount of heat storage of the hot water storage tank 6.

In the embodiments 1 and 2 described above, the examples have been described in which the refrigerant pipe 18 of the condenser 17 is wound around the outer periphery of the hot water storage tank 6. However, as a modification, the refrigerant pipe 18 of the condenser 17 may be provided in the hot water storage tank 6. For example, the refrigerant pipe 18 having a helical shape or a coil shape may be disposed in a state of being in contact with the inner wall surface of the hot water storage tank 6. Alternatively, the refrigerant pipe 18 having a helical shape or a coil shape may be disposed in such a way as to be immersed in the water in the hot water storage tank 6 without being in contact with the inner wall surface of the hot water storage tank 6.

Of the features of the plurality of embodiments described above, two or more features that can be combined may be implemented in combination.

REFERENCE SIGNS LIST

• • 1 storage type hot water supplying apparatus
  • 2 heat source machine
  • 3 tank unit
  • 4 extension pipe
  • 5 extension pipe
  • 6 hot water storage tank
  • 7 feed water inlet
  • 8 hot water outlet
  • 9 feed water pipe
  • 10) hot water supply pipe
  • 11 evaporator
  • 12 compressor
  • 13 expansion valve
  • 14 control circuitry
  • 15 blower
  • 17 condenser
  • 17A upper part
  • 17B lower part
  • 18 refrigerant pipe
  • 18 a recessed portion
  • 18 b flat part
  • 18 c upper protruding part
  • 18 d lower protruding part
  • 18 e groove part
  • 19 user interface
  • 20 heat-conductive material

Claims

1. A storage type hot water supplying apparatus, comprising: a hot water storage tank; anda condenser located at the hot water storage tank and including a refrigerant pipe that is centered on a vertical line and that has a helical shape,wherein the condenser has an upper part and a lower part located lower than the upper part,and wherein a vertical length of a vertical cross-sectional shape of the refrigerant pipe in the lower part of the condenser is shorter than a vertical length of a vertical cross-sectional shape of the refrigerant pipe in the upper part of the condenser.

2. The storage type hot water supplying apparatus according to claim 1, wherein a pitch of a helix formed by the refrigerant pipe in the lower part of the condenser is smaller than a pitch of a helix formed by the refrigerant pipe in the upper part of the condenser.

3. The storage type hot water supplying apparatus according to claim 1, wherein the vertical length of the vertical cross-sectional shape of the refrigerant pipe in the upper part of the condenser is 1.1 times or more and 3 times or less the vertical length of the vertical cross-sectional shape of the refrigerant pipe in the lower part of the condenser.

4. The storage type hot water supplying apparatus according to claim 1, wherein a vertical dimension of the upper part of the condenser is 1.2 times or more and 20 times or less a vertical dimension of the lower part of the condenser.

5. The storage type hot water supplying apparatus according to claim 1, wherein the number of turns of a helix formed by the refrigerant pipe in the upper part of the condenser is larger than the number of turns of a helix formed by the refrigerant pipe in the lower part of the condenser.

6. The storage type hot water supplying apparatus according to claim 1, wherein the refrigerant pipe is wound around the hot water storage tank at a position between a heat insulating material and a surface of the hot water storage tank, the heat insulating material covering an outer periphery of the hot water storage tank.

7. The storage type hot water supplying apparatus according to claim 1, wherein a value obtained by dividing the vertical length of the vertical cross-sectional shape of the refrigerant pipe by a horizontal length of the vertical cross-sectional shape of the refrigerant pipe is used as an aspect ratio, and an aspect ratio of the refrigerant pipe in the lower part of the condenser is smaller than an aspect ratio of the refrigerant pipe in the upper part of the condenser.

8. The storage type hot water supplying apparatus according to claim 1, comprising: a compressor configured to compress refrigerant; anda refrigerant passage configured to couple the compressor to the condenser, whereinthe refrigerant flows from the refrigerant pipe in the upper part of the condenser to the refrigerant pipe in the lower part of the condenser.

9. The storage type hot water supplying apparatus according to claim 8, wherein, during a hot water storage operation, being an operation that supplies the refrigerant from the compressor to the condenser, the refrigerant pipe in the lower part of the condenser is filled with refrigerant in a liquid phase, and the refrigerant pipe in the upper part of the condenser is filled with refrigerant in a superheated gas state or refrigerant in a gas-liquid two-phase state.

10. The storage type hot water supplying apparatus according to claim 1, wherein the vertical cross-sectional shape of the refrigerant pipe in the upper part of the condenser is a cocoon shape or an elliptical shape.

11. The storage type hot water supplying apparatus according to claim 1, wherein the vertical cross-sectional shape of the refrigerant pipe in the lower part of the condenser is a D shape, a circular shape, or a C shape.