JP2021004710A - Hot water storage type hot water supply device - Google Patents

Abstract

To provide a hot water storage type hot water supply device that is advantageous for improving durability of pipes connected to a hot water storage tank while reducing manufacturing costs.SOLUTION: A hot water storage type hot water supply device 100 comprises: a hot water storage tank 10 made of metal; dissimilar metal pipes (a water supply pipe 2, a tank lower part pipe 40, and a lower part return pipe 44) connected to the hot water storage tank 10, and made of metal of a kind different from that of the hot water storage tank 10; and insulation joints (a water supply connection part 81, a tank lower part pipe connection part 82, and a lower part return pipe connection part 83) interposed between the hot water storage tank 10 and the dissimilar metal pipes, and electrically insulating the hot water storage tank 10 from the dissimilar metal pipes.SELECTED DRAWING: Figure 1

Description

The present invention relates to a hot water storage type hot water supply device.

In the water heater disclosed in Patent Document 1 below, a hot water supply unit and a water supply unit are provided in a tank housed inside an outer cylinder via a heat insulating material, and a hot water supply port body and a water supply port body are provided in the outer cylinder. Is connected to the hot water supply port body and between the water supply unit and the water supply port body by a pipe made of rubber or synthetic resin which is flexible and has high electrical insulation. This pipe is arranged so as to wind a tongue with a margin in length.

Jitsukosho 48-011956

The pressure inside the hot water storage tank becomes high due to the pressure from the water source. Therefore, the pressure inside the pipe connected to the hot water storage tank also becomes high. The technique of Patent Document 1 has a problem of low durability because a pipe made of rubber or synthetic resin and having low strength against pressure is extended for a long time.

On the other hand, when a high-strength metal pipe is connected to the hot water storage tank, metal corrosion may occur, so that the durability may not be sufficiently improved.

The present invention has been made to solve the above-mentioned problems, and provides a hot water storage type hot water supply device which is advantageous in improving the durability of the piping connected to the hot water storage tank while suppressing the manufacturing cost. The purpose is to do.

The hot water storage type hot water supply device according to the present invention is connected to a metal hot water storage tank and a dissimilar metal pipe made of a different type of metal from the hot water storage tank, and between the hot water storage tank and the dissimilar metal pipe. It is provided with an insulating joint that is interposed and electrically insulates the hot water storage tank from dissimilar metal pipes.

According to the present invention, it is possible to provide a hot water storage type hot water supply device which is advantageous in improving the durability of a pipe connected to a hot water storage tank while suppressing a manufacturing cost.

It is a figure which shows the hot water storage type hot water supply apparatus by Embodiment 1. FIG. It is a figure which shows the hot water storage type hot water supply apparatus by Embodiment 2.

Hereinafter, embodiments will be described with reference to the drawings. The common or corresponding elements in the drawings are designated by the same reference numerals to simplify or omit the common description.

Embodiment 1.
FIG. 1 is a diagram showing a hot water storage type hot water supply device 100 according to the first embodiment. As shown in FIG. 1, the hot water storage type hot water supply device 100 includes a hot water storage unit 1 and a heat pump unit 60 configured to utilize a heat pump cycle. The hot water storage unit 1 and the heat pump unit 60 are connected via a heat pump inlet pipe 41, a heat pump outlet pipe 42, and electrical wiring (not shown).

The hot water storage unit 1 has a built-in control unit 70. Electrical devices such as various sensors and actuators included in the hot water storage unit 1 and the heat pump unit 60 are electrically connected to the control unit 70. The control unit 70 corresponds to a control means for controlling the operation of the hot water storage type hot water supply device 100. The control unit 70 may have, for example, at least one memory and at least one processor.

Bidirectional communication is possible between the control unit 70 and the remote controller 71 by wired communication or wireless communication. The control unit 70 and the remote controller 71 may be able to communicate with each other via a network. The remote controller 71 is an example of a user interface. The remote controller 71 has an operation unit operated by a person and a display unit for displaying information. By operating the remote controller 71, a person such as a user can remotely control the hot water storage type hot water supply device 100 and make various settings. The display unit of the remote controller 71 has a function as a notification means for notifying a person such as a user of information. The remote controller 71 may be provided with other notification means such as a voice guidance device. The remote controller 71 may be installed on a wall such as a kitchen, a living room, or a bathroom. A plurality of remote controllers 71 may be able to communicate with the control unit 70. Instead of or in addition to the remote control 71, a mobile terminal such as a smartphone may be available as a user interface.

The control unit 70 may be able to communicate with other devices such as a home energy management system. Further, the control unit 70 may be able to communicate with an external server, for example, via a communication line such as the Internet.

The heat pump unit 60 corresponds to a water heating means for heating the water led from the hot water storage unit 1. The heat pump unit 60 has a refrigerant circuit in which a compressor 61, a heating heat exchanger 62, an expansion valve 63, and an air heat exchanger 64 are cyclically connected by a refrigerant circulation pipe 65, and the refrigerating cycle, that is, the refrigerating cycle, that is, is performed by the refrigerant circuit. The heat pump cycle can be operated. The boiling heat exchanger 62 exchanges heat between the refrigerant compressed by the compressor 61 and the water derived from the hot water storage unit 1. The HP outlet side thermistor 66 provided in the heat pump outlet pipe 42 is a temperature sensor for detecting the temperature of the hot water flowing out from the boiling heat exchanger 62 (hereinafter, referred to as “heat pump outlet temperature”). The heat pump unit 60 further includes an outside air temperature thermistor 67, which is a temperature sensor for detecting the outside air temperature. In order to obtain high temperature water in the heat pump unit 60, it is advantageous that the heat pump cycle uses, for example, carbon dioxide as a refrigerant and operates at a pressure exceeding the critical pressure.

The hot water storage unit 1 contains the following various parts and pipes. The hot water storage tank 10 is for storing hot water. The hot water storage tank 10 is made of metal. The hot water storage tank 10 may be made of, for example, stainless steel. The hot water storage tank 10 is covered with a heat insulating material (not shown) in order to keep the hot water warm. Typically, the hot water storage tank 10 has a cylindrical outer shape having a central axis parallel to the vertical line. Each of the top and bottom of the hot water storage tank 10 may have a bowl-shaped or hemispherical shape having an outer surface having a convex curved surface.

A water supply pipe 2 for flowing low-temperature water supplied from a water source such as city water into the hot water storage tank 10 is connected to the lower part of the hot water storage tank 10. One end of the tank upper pipe 43 is connected to the upper part of the hot water storage tank 10. The hot water supply pipe 3 branches from the branch portion 48 formed in the middle of the tank upper pipe 43. The water supply temperature thermistor 7 installed in the water supply pipe 2 is a temperature sensor that detects the water supply temperature, which is the temperature of the water in the water supply pipe 2. The high-temperature water heated by the heat pump unit 60 flows into the upper part of the hot water storage tank 10 from the tank upper pipe 43. The low temperature water from the water supply pipe 2 flows into the lower part of the hot water storage tank 10. In the hot water storage tank 10, hot water is stored so that a temperature stratification occurs in which the upper side is high temperature and the lower side is low temperature because the specific gravity of water differs depending on the temperature.

The hot water supply pipe 3 and the water supply pipe 4 branched from the water supply pipe 2 are connected to the hot water supply mixing valve 33. The hot water supply mixing valve 33 adjusts the hot water supply temperature by adjusting the mixing ratio of the hot water from the hot water supply pipe 3 and the water from the water supply pipe 4. The hot water mixed by the hot water supply mixing valve 33 is supplied to an external hot water supply destination such as a hot water supply tap through the hot water supply pipe 5. The hot water supply temperature thermistor 6 is a temperature sensor that detects the temperature of hot water passing through the hot water supply pipe 5. The hot water supply flow rate sensor 8 detects the flow rate of hot water passing through the hot water supply pipe 5.

A circulation pump 21 and a user-side heat exchanger 22 are provided in the hot water storage unit 1. The circulation pump 21 is a pump for circulating hot water through various pipes in the hot water storage unit 1. The user side heat exchanger 22 is a heat exchanger for heating the fluid to be heated on the secondary side by using the high temperature water supplied from the hot water storage tank 10 or the heat pump unit 60. The fluid to be heated is, for example, bathtub water circulating from the bathtub 50, a heat medium for heating, or the like. In the present embodiment, as a configuration on the secondary side of the user-side heat exchanger 22, a bathtub water circulation circuit 51 that circulates bathtub water flowing out of the bathtub 50 will be described as an example. The user-side heat exchanger 22 is installed in the middle of the bathtub water circulation circuit 51. Further, in the middle of the bathtub water circulation circuit 51, a secondary side circulation pump 52 for circulating the bathtub water and a bathtub outlet side thermista 53 which is a temperature sensor for detecting the temperature of the bathtub water discharged from the bathtub 50. , The water flow detection switch 54 that detects the presence or absence of water flow in the bathtub water circulation circuit 51, and the bathtub inlet side thermista 55 that is a temperature sensor for detecting the temperature of the bathtub water returning from the user side heat exchanger 22 to the bathtub 50. is set up.

The hot water storage unit 1 includes a three-way valve 31 and a four-way valve 200. The three-way valve 31 is a flow path switching means having two inlets, a port and b port, from which hot water flows in, and a c port, which is one outlet from which hot water flows out, and is either a port or b port. It is configured so that the hot water route can be switched so that hot water flows in from. The four-way valve 200 is a flow path switching means having two inlets, b port and c port, from which hot water flows in, and a port and d port, which are two outlets from which hot water flows out, and is between a and b ports. The flow path form can be switched between three routes: a route in which the ports communicate with each other, a route in which the a-c ports communicate with each other, and a route in which the cd ports communicate with each other.

The hot water storage unit 1 further includes a tank lower pipe 40, a lower return pipe 44, a user side heat exchanger primary side inlet pipe 45, a user side heat exchanger primary side outlet pipe 46, and a bypass pipe 47. The tank lower pipe 40 connects the lower part of the hot water storage tank 10 with the a port of the three-way valve 31. The heat pump inlet pipe 41 connects the c port of the three-way valve 31 and the water inlet of the boiling heat exchanger 62. A circulation pump 21 is connected in the middle of the heat pump inlet pipe 41. The heat pump outlet pipe 42 connects the water outlet of the boiling heat exchanger 62 and the c port of the four-way valve 200. The other end of the tank upper pipe 43 is connected to the d port of the four-way valve 200. The lower return pipe 44 connects the a port of the four-way valve 200 and the lower part of the hot water storage tank 10. The user-side heat exchanger primary side inlet pipe 45 branches from a branch portion 49 formed in the middle of the tank upper pipe 43 and is connected to the user-side heat exchanger 22 primary side inlet. The user side heat exchanger primary side outlet pipe 46 connects the primary side outlet of the user side heat exchanger 22 and the b port of the three-way valve 31. The bypass pipe 47 branches from the branch portion 56 formed in the heat pump inlet pipe 41 downstream of the circulation pump 21 and is connected to the b port of the four-way valve 200.

On the surface of the hot water storage tank 10, a plurality of hot water storage temperature sensors 11 and 12 are attached at different height positions. By detecting the temperature distribution of the hot water in the hot water storage tank 10 in the vertical direction by the hot water storage temperature sensors 11 and 12, the control unit 70 can calculate the amount of hot water stored and the amount of heat stored in the hot water storage tank 10. The control unit 70 starts and ends the boiling operation described later according to the amount of hot water stored or the amount of heat stored.

In the illustrated example, two hot water storage temperature sensors 11 and 12 are attached, but a larger number of hot water storage temperature sensors may be provided. The hot water storage temperature sensor 11 detects the temperature of the hot water stored in the upper part of the hot water storage tank 10. The hot water storage temperature sensor 12 detects the temperature of the hot water stored in the lower part of the hot water storage tank 10. In the following description, the water temperature detected by the hot water storage temperature sensor 12 is referred to as "tank lower temperature".

The hot water storage type hot water supply device 100 can execute a boiling operation in which the water stored in the hot water storage tank 10 is heated by the heat pump unit 60. The control unit 70 controls the boiling operation as follows. The heat pump unit 60 and the circulation pump 21 are operated. The lower water in the hot water storage tank 10 is sent to the heat pump unit 60 through the tank lower pipe 40, the three-way valve 31, and the heat pump inlet pipe 41. The hot water heated by the heat pump unit 60 flows into the upper part of the hot water storage tank 10 through the heat pump outlet pipe 42, the four-way valve 200, and the tank upper pipe 43. The control unit 70 may control the operation of at least one of the heat pump unit 60 and the circulation pump 21 so that the heat pump outlet temperature detected by the HP outlet side thermistor 66 becomes equal to the target temperature. When the amount of heat stored in the hot water storage tank 10 reaches the target amount of heat storage, the control unit 70 may end the boiling operation.

The hot water storage type hot water supply device 100 can execute a lower return operation of returning the water that has passed through the heat pump unit 60 to the lower part of the hot water storage tank 10. At the time of lower return operation, it becomes as follows. The lower water in the hot water storage tank 10 is sent to the heat pump unit 60 through the tank lower pipe 40, the three-way valve 31, and the heat pump inlet pipe 41. The water that has passed through the heat pump unit 60 flows into the lower part of the hot water storage tank 10 through the heat pump outlet pipe 42, the four-way valve 200, and the lower return pipe 44. The control unit 70 may execute the lower return operation at the start of the boiling operation. Immediately after the heat pump unit 60 is started, the temperatures of the compressor 61 and the boiling heat exchanger 62 are low, so it takes time for the heat pump outlet temperature to rise. The control unit 70 may execute the lower return operation while the heat pump outlet temperature rises, and after the heat pump outlet temperature has risen sufficiently, shift to the boiling operation by switching the four-way valve 200. As a result, it is possible to reliably prevent the temperature of the upper part of the hot water storage tank 10 from dropping at the start of the boiling operation.

Each of the water supply pipe 2, the tank lower pipe 40, and the lower return pipe 44 corresponds to a dissimilar metal pipe made of a different type of metal from the hot water storage tank 10. It is desirable that the dissimilar metal pipes are made of a metal (for example, copper) that is easier to bend than stainless steel. In general, since the route of the pipe inside the water heater is narrow, it is necessary to use a pipe having a large bend or a pipe having a plurality of bends. In the present embodiment, each of the water supply pipe 2, the tank lower pipe 40, and the lower return pipe 44 is made of a metal that can be easily bent, such as copper, to reduce the processing cost of these pipes. can do.

The water supply pipe 2 is connected to the hot water storage tank 10 via a water supply connection portion 81 having electrical insulation. The water supply connection portion 81 has one end connected to the hot water storage tank 10 and the other end connected to the water supply pipe 2. The water supply pipe 2 is not in contact with the hot water storage tank 10.

The tank lower pipe 40 is connected to the hot water storage tank 10 via a tank lower pipe connecting portion 82 having electrical insulation. The tank lower pipe connection portion 82 has one end connected to the hot water storage tank 10 and the other end connected to the tank lower pipe 40. The tank lower pipe 40 is not in contact with the hot water storage tank 10.

The lower return pipe 44 is connected to the hot water storage tank 10 via a lower return pipe connection portion 83 having electrical insulation. The lower return pipe connecting portion 83 has one end connected to the hot water storage tank 10 and the other end connected to the lower return pipe 44. The lower return pipe 44 is not in contact with the hot water storage tank 10.

Each of the water supply connection portion 81, the tank lower pipe connection portion 82, and the lower return pipe connection portion 83 is interposed between the hot water storage tank 10 and the dissimilar metal pipes to electrically insulate the hot water storage tank 10 from the dissimilar metal pipes. Corresponds to a joint. The insulating joint may be made of resin such as plastic or ceramics, for example. The connecting means for connecting the dissimilar metal pipes to the insulating joint or the connecting means for connecting the insulating joint to the port formed in the hot water storage tank 10 may have any configuration, for example, a quick fastener by a leaf spring, a fixing band, or the like. Fixtures may be used, or flanges formed on both sides may be connected to each other with bolts.

If the dissimilar metal pipe is in contact with the hot water storage tank 10, contact corrosion of dissimilar metals may occur. Galvanic corrosion of dissimilar metals is also called galvanic corrosion. Galvanic corrosion occurs by joining metals with different ionization tendencies. At this junction, a local battery is formed by the potential difference, and a current flows due to the electromotive force of the local battery, so that the metal is corroded.

On the other hand, in the present embodiment, by providing the above-mentioned insulating joint, contact corrosion of dissimilar metals can be reliably prevented. Therefore, it is advantageous in improving the durability of the water supply pipe 2, the tank lower pipe 40, the lower return pipe 44, and the hot water storage tank 10.

The pressure from the water source acts on the hot water storage tank 10 via the water supply pipe 2, so that the inside of the hot water storage tank 10 becomes high pressure. Therefore, the pressure inside the pipe connected to the hot water storage tank 10 also becomes high. If the water supply pipe 2, the tank lower pipe 40, and the lower return pipe 44 are made of rubber or synthetic resin, it becomes difficult for these pipes to exhibit sufficient strength against high pressure for a long period of time, and the durability is improved. Hard to improve. On the other hand, in the present embodiment, since the water supply pipe 2, the tank lower pipe 40, and the lower return pipe 44 are made of metal, these pipes can exhibit sufficient strength against high pressure for a long period of time and are durable. It is advantageous in improving the sex.

Dissolved oxygen is contained in the low-temperature water flowing from the water supply pipe 2 into the hot water storage tank 10. Dissolved oxygen accelerates metal corrosion. When the low-temperature water is heated by the heat pump unit 60 to become high-temperature water, the amount of dissolved oxygen decreases. Since high-temperature water having a small amount of dissolved oxygen is often stored in the upper part of the hot water storage tank 10, the metal is less likely to corrode. In contrast, low-temperature water having a large amount of dissolved oxygen is often stored in the lower part of the hot water storage tank 10, so that metal corrosion is likely to be promoted. On the other hand, in the present embodiment, the insulating joint is provided between each of the water supply pipe 2, the tank lower pipe 40, and the lower return pipe 44 connected to the lower part of the hot water storage tank 10 and the hot water storage tank 10. By interposing, it is possible to surely prevent the occurrence of metal corrosion even if the amount of dissolved oxygen is large.

The height H1 in FIG. 1 is the height at the position where the water supply pipe 2 is connected to the hot water storage tank 10. The position of the intersection of the center line of either the end of the water supply pipe 2 and the water supply connection portion 81 or its extension line with the outer wall surface of the hot water storage tank 10 is the position where the water supply pipe 2 is connected to the hot water storage tank 10. You may consider it.

The height H2 in FIG. 1 is the height at the position where the lower return pipe 44 is connected to the hot water storage tank 10. The lower return pipe 44 connects the center line of either the end of the lower return pipe 44 and the lower return pipe connection portion 83 or an extension line thereof to the position of the intersection of the outer wall surface of the hot water storage tank 10 with the hot water storage tank 10. It may be regarded as the position.

The height H3 in FIG. 1 is the height at the position where the tank lower pipe 40 is connected to the hot water storage tank 10. The tank lower pipe 40 connects the hot water storage tank 10 to the position of the intersection of the center line or the extension line of either the end of the tank lower pipe 40 and the tank lower pipe connection portion 82 and the outer wall surface of the hot water storage tank 10. It may be regarded as the position.

In the present embodiment, the height H2 at the position where the lower return pipe 44 is connected to the hot water storage tank 10 is lower than the height H1 at the position where the water supply pipe 2 is connected to the hot water storage tank 10. Further, the height H3 at the position where the tank lower pipe 40 is connected to the hot water storage tank 10 is lower than the height H2 at the position where the lower return pipe 44 is connected to the hot water storage tank 10. In the illustrated example, the height H3 corresponds to the bottom of the hot water storage tank 10.

In the following description, the pipe connected to the hot water storage tank 10 at a height lower than the height H1 at the position where the water supply pipe 2 is connected to the hot water storage tank 10 is referred to as a lower pipe. Each of the tank lower pipe 40 and the lower return pipe 44 corresponds to the lower pipe. Further, the tank lower pipe 40 corresponds to the first lower pipe, and the lower return pipe 44 corresponds to the second lower pipe. In the hot water storage tank 10, the lower the height, the lower the water temperature and the larger the dissolved oxygen amount. Therefore, assuming that the lower pipe is directly connected to the hot water storage tank 10, contact corrosion of dissimilar metals is likely to occur. On the other hand, in the present embodiment, by providing the insulating joints for each of the tank lower pipe 40 and the lower return pipe 44, it is possible to more reliably prevent the occurrence of galvanic corrosion of dissimilar metals.

In the present embodiment, the tank upper pipe 43 is made of a metal different from that of the hot water storage tank 10, for example, copper. By making the tank upper pipe 43 made of a metal such as copper that can be easily bent, the processing cost of the pipe can be reduced. The tank upper pipe 43 is connected to the hot water storage tank 10 without an insulating joint. Since high-temperature water having a small amount of dissolved oxygen is often stored in the upper part of the hot water storage tank 10, the metal is less likely to corrode. Therefore, even if the tank upper pipe 43 is connected to the hot water storage tank 10 without an insulating joint, it is possible to reliably prevent the occurrence of galvanic corrosion of dissimilar metals. The tank upper pipe 43 corresponds to an upper pipe connected to the hot water storage tank 10 without an insulating joint at a position higher than the position H1 in which the water supply pipe 2 is connected to the hot water storage tank 10. In the present embodiment, since the upper pipe is connected to the hot water storage tank 10 without an insulating joint, it is possible to prevent an increase in the number of parts and an increase in the assembly process, and it is possible to reduce the manufacturing cost. Will be advantageous. The upper pipe is not limited to the one connected to the upper part of the hot water storage tank 10, but may be connected to the body of the hot water storage tank 10.

It is known that water quality varies from region to region. Different water qualities are more susceptible to metal corrosion. In the following description, an area with water quality that is relatively less corrosive to metals is referred to as a "general area", and an area with water quality that is more corrosive than general areas is referred to as a "specific area". For example, an area of water quality in which the dissolved oxygen concentration is higher than that of a general area corresponds to a specific area. Further, the more a substance having a high conductivity is contained in water, the more easily the metal is corroded. Therefore, the area of water quality where the concentration of the substance is higher than that of the general area corresponds to a specific area. The control unit 70 may store information about a general area and a specific area in a memory, or may receive information from another device by communication.

The hot water storage type hot water supply device 100 may include an input means for inputting information on the area where the hot water storage type hot water supply device 100 is installed, that is, information on the location of the hot water storage type hot water supply device 100 to the control unit 70. For example, the remote controller 71 may be used as an input means so that the user or other person can input the location information of the hot water storage type hot water supply device 100 to the control unit 70 by operating the remote controller 71. Further, the control unit 70 may receive information on the location of the hot water storage type hot water supply device 100 from another device by communication. The control unit 70 determines whether the hot water storage type hot water supply device 100 is installed in the general area or the specific area based on the information on the general area and the specific area and the information on the location of the hot water storage type hot water supply device 100. can do.

In the control unit 70, when the hot water storage type hot water supply device 100 is installed in a specific area, the hot water temperature at the lower part of the hot water storage tank 10 becomes higher than when the hot water storage type hot water supply device 100 is installed in a general area. The lower heating control that performs the boiling operation may be executed as described above. In this lower heating control, the control unit 70 may execute the boiling operation until the tank lower temperature detected by the hot water storage temperature sensor 12 becomes equal to or higher than a predetermined temperature. According to this lower heating control, the temperature of the lower part of the hot water storage tank 10 increases, so that the dissolved oxygen concentration in the lower part of the hot water storage tank 10 decreases. As a result, even in the hot water storage type hot water supply device 100 installed in a specific area, it is possible to more reliably prevent corrosion of the water supply pipe 2, the tank lower pipe 40, the lower return pipe 44, and the like.

The control unit 70 may prohibit the boiling operation when the information of the area where the hot water storage type hot water supply device 100 is installed is not input. As a result, it is possible to urge the user or other person to input information on the area where the hot water storage type hot water supply device 100 is installed.

The hot water storage type hot water supply device 100 includes a hot water supply usage amount detecting means for detecting the hot water supply usage amount. In the present embodiment, the hot water supply temperature thermistor 6 and the hot water supply flow rate sensor 8 correspond to the hot water supply usage amount detecting means. The control unit 70 can calculate the amount of hot water used based on the detected value of the hot water temperature thermistor 6 and the detected value of the hot water flow rate sensor 8. For example, the control unit 70 may calculate the amount of heat of the hot water supplied through the hot water supply pipe 5 as the amount of hot water used, or the volume obtained by converting the amount of heat into the amount of hot water at the reference hot water supply temperature as the amount of hot water used. You may calculate.

As the amount of hot water used increases, the amount of low-temperature water flowing from the water supply pipe 2 into the hot water storage tank 10 increases, so that the amount of dissolved oxygen flowing into the hot water storage tank 10 together with the low-temperature water also increases. Therefore, it can be said that the larger the amount of hot water used, the larger the amount of dissolved oxygen in the hot water storage tank 10, and the greater the possibility of corrosion. In view of this, in the boiling operation, when the amount of hot water used since the previous boiling operation is relatively large, the hot water storage tank 10 is more than when the amount of hot water used is relatively small. The lower heating control may be executed in which the boiling operation is performed so that the temperature of the lower part of the water heater becomes high. In this lower heating control, the control unit 70 may execute the boiling operation until the tank lower temperature detected by the hot water storage temperature sensor 12 becomes equal to or higher than a predetermined temperature. According to this lower heating control, the temperature of the lower part of the hot water storage tank 10 increases, so that the dissolved oxygen concentration in the lower part of the hot water storage tank 10 decreases. As a result, even when the amount of hot water used is large, it is possible to more reliably prevent corrosion of the water supply pipe 2, the tank lower pipe 40, the lower return pipe 44, and the like.

The hot water storage type hot water supply device 100 may include a notification means for notifying information regarding whether or not lower heating control is executed. For example, the user or the like may be notified by displaying information on whether or not the lower heating control is executed on the display unit of the remote controller 71. As a result, convenience can be improved.

Embodiment 2.
Next, the second embodiment will be described with reference to FIG. 2, but the differences from the first embodiment will be mainly described, and the elements common to or corresponding to the above-mentioned elements have the same reference numerals. Is added to simplify or omit the common description. FIG. 2 is a diagram showing a hot water storage type hot water supply device 100 according to the second embodiment. As shown in FIG. 2, the hot water storage type hot water supply device 100 of the present embodiment includes a lower heater 85 arranged at the lower part in the hot water storage tank 10. The lower heater 85 corresponds to a lower heating means for heating the water in the lower part of the hot water storage tank 10. The control unit 70 controls the on / off of the lower heater 85.

The control unit 70 executes lower heating control to operate the lower heater 85 when a hot water storage type hot water supply device is installed in a specific area during the boiling operation, and the hot water storage type hot water supply device is installed in a general area. If so, the lower heater 85 may not be operated. In this lower heating control, the control unit 70 heats the water in the lower part of the hot water storage tank 10 by turning on the lower heater 85 after the boiling operation is completed, and the tank lower temperature detected by the hot water storage temperature sensor 12 is a predetermined temperature. When the above is reached, the lower heater 85 may be turned off. According to this lower heating control, the temperature of the lower part of the hot water storage tank 10 increases, so that the dissolved oxygen concentration in the lower part of the hot water storage tank 10 decreases. As a result, even in the hot water storage type hot water supply device 100 installed in a specific area, it is possible to more reliably prevent corrosion of the water supply pipe 2, the tank lower pipe 40, the lower return pipe 44, and the like.

In the present embodiment, by providing the lower heater 85, the temperature of the lower part of the hot water storage tank 10 can be raised more reliably. Further, since it is not necessary to raise the temperature of the hot water at the lower part of the hot water storage tank 10 by the boiling operation, it is possible to prevent the temperature of water entering the heat pump unit 60 from rising during the boiling operation. Therefore, it is possible to prevent a decrease in the coefficient of performance of the heat pump unit 60 due to an increase in the water entry temperature.

In the illustrated example, the lower heater 85 is arranged in a height region including the heights H1, H2, and H3 described in the first embodiment. As in this example, at least a part of the lower heater 85 is located at a position where at least one of the water supply pipe 2, the tank lower pipe 40, and the lower return pipe 44 is connected to the hot water storage tank 10. It is desirable that they are at the same height. As a result, the hot water temperature at the position where the dissimilar metal pipe is connected to the hot water storage tank 10 can be raised more reliably, so that corrosion can be prevented more reliably.

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

1 Hot water storage unit, 1 User side heat exchanger, 2 Water supply pipe, 3 Hot water supply pipe, 4 Water supply pipe, 5 Hot water supply pipe, 6 Hot water supply temperature thermistor, 7 Water supply temperature thermista, 8 Hot water supply flow sensor, 10 Hot water storage tank, 11, 12 Hot water storage Temperature sensor, 21 Circulation pump, 22 User side heat exchanger, 31 Three-way valve, 33 Hot water supply mixing valve, 40 Tank lower piping, 41 Heat pump inlet piping, 42 Heat pump outlet piping, 43 Tank upper piping, 44 Lower return piping, 45 Utilization Side heat exchanger primary side inlet piping, 46 User side heat exchanger primary side outlet piping, 47 Bypass piping, 48 branching section, 49 branching section, 50 tub, 51 tub water circulation circuit, 52 Secondary side circulation pump, 53 Bath outlet side thermister, 54 Water flow detection switch, 55 Bath inlet side thermister, 56 Branch, 60 Heat pump unit, 61 Compressor, 62 Boiling heat exchanger, 63 Expansion valve, 64 Air heat exchanger, 65 Coolant circulation piping , 66 Outlet side thermistor, 67 Outside air temperature thermistor, 70 Control unit, 71 Remote control, 81 Water supply connection part, 82 Tank lower pipe connection part, 83 Lower return pipe connection part, 85 Lower heater, 100 Hot water storage type hot water supply device, 200 Four-way valve

Claims (13)

With a metal hot water storage tank
Dissimilar metal piping connected to the hot water storage tank and made of a different type of metal from the hot water storage tank,
An insulating joint that is interposed between the hot water storage tank and the dissimilar metal pipe and electrically insulates the hot water storage tank from the dissimilar metal pipe.
A hot water storage type hot water supply device equipped with. Equipped with a water supply pipe that allows water supplied from the water source to flow into the hot water storage tank.
The hot water storage type hot water supply device according to claim 1, wherein the water supply pipe corresponds to the dissimilar metal pipe. A lower pipe connected to the hot water storage tank is provided at a position lower than the position where the water supply pipe is connected to the hot water storage tank.
The hot water storage type hot water supply device according to claim 2, wherein the lower pipe corresponds to the dissimilar metal pipe. Water heating means to heat water and
The first lower pipe corresponding to the lower pipe and
With
The hot water storage type hot water supply device according to claim 3, wherein the water in the hot water storage tank can be supplied to the water heating means through the first lower pipe. A second lower pipe corresponding to the lower pipe is provided.
The hot water storage type hot water supply device according to claim 4, wherein the water that has passed through the water heating means can flow into the hot water storage tank through the second lower pipe. At a position higher than the position where the water supply pipe is connected to the hot water storage tank, an upper pipe connected to the hot water storage tank without passing through the insulating joint is provided.
The hot water storage type hot water supply device according to any one of claims 2 to 5, wherein the upper pipe is made of a metal of a type different from that of the hot water storage tank. Water heating means to heat water and
A control means for controlling a boiling operation in which the water stored in the hot water storage tank is heated by the water heating means, and
With
When the hot water storage type hot water supply device is installed in a specific area of water quality having higher corrosiveness than the general area, the control means is more than when the hot water storage type hot water supply device is installed in the general area. The hot water storage type hot water supply device according to any one of claims 1 to 6, wherein the lower heating control for performing the boiling operation is performed so that the temperature of the lower part of the hot water storage tank becomes high. Water heating means to heat water and
A control means for controlling a boiling operation in which the water stored in the hot water storage tank is heated by the water heating means, and
A lower heating means for heating the water in the lower part of the hot water storage tank, and
With
The control means is a lower heating control that operates the lower heating means when the hot water storage type hot water supply device is installed in a specific area of water quality having higher corrosiveness than a general area during the boiling operation. The hot water storage type hot water supply device according to any one of claims 1 to 6, wherein the lower heating means is not operated when the hot water storage type hot water supply device is installed in the general area. The hot water storage type hot water supply device according to claim 8, wherein at least a part of the lower heating means is at a position at the same height as a position where the dissimilar metal pipe is connected to the hot water storage tank. Water heating means to heat water and
A control means for controlling a boiling operation in which the water stored in the hot water storage tank is heated by the water heating means, and
Hot water usage detection means for detecting hot water usage and
With
When the amount of hot water supplied since the previous boiling operation is relatively large during the boiling operation, the control means lowers the hot water in the hot water storage tank as compared with the case where the amount of hot water used is relatively small. The hot water storage type hot water supply device according to any one of claims 1 to 6, which executes the lower heating control that performs the boiling operation so that the temperature becomes high. The hot water storage type hot water supply device according to any one of claims 7 to 9, further comprising an input means for inputting information on the area where the hot water storage type hot water supply device is installed into the control means. The hot water storage type hot water supply device according to claim 11, wherein the control means prohibits the boiling operation when the information of the area is not input. The hot water storage type hot water supply device according to any one of claims 7 to 10, further comprising a notification means for notifying information regarding the presence / absence of execution of the lower heating control.

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