Hot water supply system

Abstract

Even when the enclosure is divided into a heating side enclosure and a tank side enclosure, the drainage operation from the tank can be performed with good operability. [Solution] The housing 100 of the heat pump heat source unit 1 is divided into a lower frame 102 that houses at least the tank body 20 and an upper frame 101 that houses at least the heat pump unit 2, and the upper frame 101 is placed on top of the lower frame 102 and joined together. The pressure relief pipe 58 and the pressure relief valve 59 are provided on the lower frame 102, and by opening the first solenoid valve 36 and the pressure relief valve 59 using the heat source unit controller, it is possible to discharge the hot water from the tank body 20.

Description

Technical Field

[0001] The present disclosure relates to a hot water supply device that heats water with a heating means such as a heat pump, stores the hot water in a tank, and enables hot water to be discharged from the tank.

Background Art

[0002] There is known a hot water supply device that heats water to a predetermined temperature using a heating means such as a heat pump, stores the hot water in a tank, and enables hot water to be discharged to the outside. For example, Patent Document 1 discloses an invention of a hot water storage and supply device that circulates and heats the water in a hot water storage tank with a heat pump type heat source machine, keeps it warm at a predetermined temperature, and enables hot water to be discharged. In this hot water storage and supply device, a drain valve is provided in a drain passage connected to the lower part of the hot water storage tank. When the drain mode is set with a remote control, the control unit sets each valve member to a drainable state corresponding to the drain mode and opens the drain valve to drain the water. Further, Patent Document 2 discloses an invention of a hot water supply machine in which a relief valve that can be opened and closed by an operation lever is provided in a drain hose connected to the upper part of the tank, the relief valve is opened by the operation lever, and the water in the tank can be discharged by operating a three-way valve at the lower part of the tank to switch the water in the tank to the water distribution pipe side.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In some hot water supply systems, the heating means, such as a heat pump, and the tank are housed in separate enclosures, dividing the system into a heating-side enclosure and a tank-side enclosure, and the piping is connected between the enclosures to form a unit. In this case, for example, if the heating-side enclosure is placed on top of the tank-side enclosure, it can be installed in a space-saving manner and offers greater flexibility in layout. However, with this type of segmented configuration, it is difficult to adopt a fully automated system for draining the water from the tank, as shown in Patent Document 1. Therefore, a system for manually draining the water from the tank, as shown in Patent Document 2, is adopted. However, depending on the layout of the housing, the operating lever may be in an inconvenient position or at an inconvenient height, which could lead to poor operability in the draining operation.

[0005] Therefore, the purpose of this disclosure is to provide a hot water supply device that allows for easy drainage from the tank even when the housing is divided into a heating-side housing and a tank-side housing. [Means for solving the problem]

[0006] To achieve the above objective, this disclosure provides a hot water supply system, A housing equipped with a water inlet and a hot water outlet, A tank for storing hot water, A heating means for heating the hot water in the tank, A water supply pipe connected to the water inlet, A hot water outlet pipe is connected between the top of the tank and the hot water outlet, and the downstream end of the water supply pipe is connected to it. A mixing valve is provided at the connection point between the water supply pipe and the hot water outlet pipe, A pressure relief pipe is connected between the upstream end of the hot water outlet pipe and the mixing valve, A pressure relief valve is provided in the aforementioned pressure relief pipe and can be opened and closed by manual operation, A drain pipe connected to the bottom of the tank, A solenoid valve is provided in the drain pipe and is capable of opening and closing the internal flow path, The system includes a controller that controls the opening and closing of the solenoid valve. Furthermore, the housing is divided into at least a tank-side housing that houses the tank and at least a heating-side housing that houses the heating means, and the heating-side housing is mounted on top of the tank-side housing and joined together. The pressure relief pipe and the pressure relief valve are provided in the tank-side housing, The controller opens the solenoid valve and the pressure relief valve, thereby enabling the discharge of hot water from the tank. Another aspect of the present disclosure is the configuration described above, wherein the pressure relief valve has a lever for opening and closing, and the lever is rotatable to a retracted position where it is housed within the tank-side housing when the valve is closed, and to a protruding position where it protrudes from the tank-side housing when the valve is open. The outer surface of the tank-side housing is provided with a panel having a window overlooking the lever, and the window is provided with an openable and closable lid. The lever is characterized in that it can be opened and closed through the window when the lid is open, and in the protruding position, it penetrates the window and protrudes outward from the panel. Another aspect of the present disclosure is characterized in that, in the above configuration, a branch section is provided upstream of the solenoid valve in the drain pipe, a branch pipe is connected to the branch section, and a manually operated drain plug is provided at the downstream end of the branch pipe. Another aspect of the present disclosure is characterized in that, in the above configuration, the heating means is a heat pump, and a circulation path is provided between the tank and the water heat exchanger of the heat pump for circulating the hot water in the tank to and from the water heat exchanger. [Effects of the Invention]

[0007] According to this disclosure, since a manually operated pressure relief valve is provided in the lower housing, even if the housing is divided into an upper housing and a lower housing, the drainage operation from the tank can be performed with good operability. In addition, since all components except the heating means and its peripheral equipment can be concentrated in the lower housing, piping connection work during manufacturing and maintenance becomes easier. According to another aspect of this disclosure, in addition to the above effects, the lever for opening and closing the pressure relief valve protrudes beyond the panel through the window when in the open position, making it easy to drain the water using the lever, and the configuration for draining the water is simple because no solenoid valve is used. Furthermore, since the cover cannot be closed by the lever when the pressure relief valve is open, it is possible to reliably prevent forgetting to close the pressure relief valve after draining the water. According to another aspect of this disclosure, in addition to the above effects, a branch section is provided upstream of the solenoid valve in the drain pipe, a branch pipe is connected to the branch section, and a manually operated drain plug is provided at the downstream end of the branch pipe. Therefore, even if the solenoid valve cannot be opened due to a power outage or malfunction, the water in the tank can be drained by opening the drain plug. According to another aspect of this disclosure, in addition to the above effects, the heating means is a heat pump, and a circulation path is provided between the tank and the heat exchanger of the heat pump to circulate the hot water in the tank to the heat exchanger. Therefore, compared to a heat source that uses fuel gas, the running costs are lower and carbon dioxide emissions are reduced. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram of a hot water supply system consisting of a heat pump heat source unit and a water heater. [Figure 2] This is a front view of a heat pump heat source unit (the front panel is omitted). [Figure 3] This is a right-side view of a heat pump heat source unit. [Figure 4] This is a cross-sectional view along line AA in Figure 3. [Figure 5] This is an enlarged view of the pressure relief valve section in Figure 4. [Figure 6] This is a right-side view of the pressure relief valve section with the window removed. [Figure 7] This is a magnified view of the pressure relief valve section with the lever in the open position. [Modes for carrying out the invention]

[0009] Hereinafter, embodiments of the present disclosure will be described based on the drawings. FIG. 1 is a schematic diagram showing a hot water supply system S including a heat pump heat source machine (hereinafter simply referred to as "heat source machine") 1 which is an example of the hot water supply device of the present disclosure, and a hot water heater 70 connected to the heat source machine 1. The heat source machine 1 includes a heat pump unit 2, a tank unit 3, a tank drain pipe 4, a heat source side water supply pipe 5, a heat source side hot water pipe 6, and a heat source machine controller 7. The heat pump unit 2 includes a compressor 10, a water heat exchanger 11, an expansion valve 12, a heat absorption unit 13, and a loop-shaped circulation path 14 connecting these in series. A heat medium (for example, alternative refrigerant) can circulate through the circulation path 14. The heat pump unit 2 is an example of a heat pump which is the heating means of the present disclosure. The compressor 10 compresses the heat medium absorbed by the heat absorption unit 13, makes it high-temperature and high-pressure, and sends it to the water heat exchanger 11. The water heat exchanger 11 includes a heat side pipe 15 and a water side pipe 16. The heat side pipe 15 is incorporated in the circulation path 14. The water side pipe 16 is incorporated in a tank circulation path 28 described later. The expansion valve 12 decompresses the heat medium whose heat has been taken away by the water heat exchanger 11, makes it low-temperature and low-pressure, and sends it to the heat absorption unit 13. The heat absorption unit 13 has a fan 17 and performs heat exchange between the outside air and the heat medium.

[0010] The tank unit 3 includes a tank body 20, a tank forward pipe 21, and a tank return pipe 22. The tank body 20 can store hot water of a predetermined capacity (for example, 25 L), and a tank temperature sensor 23 for detecting the temperature of the hot water is provided inside. The tank body 20 is an example of the tank of the present disclosure. The tank forward pipe 21 is connected to the upper part of the tank body 20. The tank forward pipe 21 is connected to the downstream end of the water side pipe 16 of the water heat exchanger 11 of the heat pump unit 2. A forward temperature sensor 24 for detecting the temperature of the hot water is provided on the tank forward pipe 21. The tank return pipe 22 is connected to the lower part of the tank body 20. The tank return pipe 22 is connected to the upstream end of the water side piping 16. The tank return pipe 22 is equipped with a pump 25, a flow switch 26 for detecting water flow, and a return temperature sensor 27 for detecting the temperature of the hot and cold water. The tank supply pipe 21, tank return pipe 22, and water side pipe 16 form a tank circulation path 28 through which the hot water inside the tank body 20 circulates. Upstream of the pump 25, a drain pipe 29 for the return pipe is connected to the tank return pipe 22. A drain plug 30 is provided at the downstream end of the drain pipe 29 for the return pipe.

[0011] The tank drain pipe 4 is connected to the bottom of the tank body 20. The tank drain pipe 4 is provided with, in order from the upstream side, a throttling section 35 for flow rate control and a first solenoid valve 36 for opening and closing the flow path. A branch section 4a is provided between the throttling section 35 and the first solenoid valve 36, and a branch pipe 4b is connected to the branch section 4a. A drain plug 37 is provided at the outlet of the branch pipe 4b. The tank drain pipe 4 is an example of a drain pipe of the present disclosure. The first solenoid valve 36 is an example of a solenoid valve of the present disclosure. The drain plug 37 is an example of a drain plug of the present disclosure. The upstream end of the heat source side water supply pipe 5 is connected to a water inlet 38 provided in the housing. An external water pipe (not shown) is connected to the water inlet 38. The heat source side water supply pipe 5 is equipped with a pressure reducing valve 39 for adjusting the water inlet pressure to the tank body 20, a heat source side flow sensor 40 for detecting the amount of water flowing, and a heat source side inlet water temperature sensor 41 for detecting the water temperature, starting from the upstream side. The heat source side water supply pipe 5 is an example of a water supply pipe in this disclosure.

[0012] Downstream of the heat source side inlet water temperature sensor 41, the heat source side water supply pipe 5 branches into a first water supply branch pipe 42 and a second water supply branch pipe 43. The first water supply branch pipe 42 is connected to a mixing valve 56, which will be described later, provided on the heat source side outlet pipe 6. The first water supply branch pipe 42 is equipped with a check valve 44 and a throttling section 45 for flow control. A water supply pipe drain pipe 46 is connected between the check valve 44 and the throttling section 45. A drain plug 47 is provided at the downstream end of the water supply pipe drain pipe 46. The second water supply branch pipe 43 is connected to the bottom of the tank body 20. The second water supply branch pipe 43 is equipped with a second solenoid valve 48 for opening and closing the flow path and a check valve 49, starting from the upstream side.

[0013] The heat source side outlet pipe 6 includes a first section pipe 55, a mixing valve 56, and a second section pipe 57. The heat source side outlet pipe 6 is an example of an outlet pipe of this disclosure. The first section pipe 55 has its upstream end connected to the top of the tank body 20 and its downstream end connected to the first inlet of the mixing valve 56. A pressure relief pipe 58 is connected to the first section pipe 55. A pressure relief valve 59 is provided in the pressure relief pipe 58. Downstream of the pressure relief pipe 58, the first section pipe 55 is equipped with an upstream temperature sensor 60 for detecting the hot water temperature at the outlet of the first section pipe 55. The mixing valve 56 is electrically operated, with the valve body of the T-port motor-driven to switch the flow path and adjust the opening degree of the flow path. The downstream end of the first water supply branch pipe 42 is connected to the second inlet of the mixing valve 56. The upstream end of the second section pipe 57 is connected to the outlet of the mixing valve 56. The second section pipe 57 is equipped with a downstream temperature sensor 61 for detecting the hot water temperature at the outlet of the second section pipe 57. A hot water outlet 62 is provided at the downstream end of the second section pipe 57.

[0014] The heat source controller 7 includes a CPU and memory connected to the CPU. The heat source controller 7 is electrically connected to the compressor 10, expansion valve 12, fan 17, and temperature sensors (not shown) located in the circulation path 14 of the heat pump unit 2. The heat source controller 7 is electrically connected to the pump 25, the first and second solenoid valves 36 and 48, and the mixing valve 56, and controls the operation of each component, while also receiving detection signals from each sensor and switch. The heat source controller 7 is an example of the controller of this disclosure. The heat source controller 7 controls the operation of the heat pump unit 2 and the hot water supply operation in the tank body 20, based on the operation commands set by the remote control 74 (described later) and each detection signal, according to a program stored in a non-temporary computer-readable storage medium including memory connected to the CPU. Note that the first solenoid valve 36 of the tank drain pipe 4 is closed during hot water supply operation.

[0015] The water heater 70 includes a gas burner 71, a heat exchanger 72, a water heater controller 73, and a remote control 74. A water supply pipe 75 is connected to the inlet end of the heat transfer tubes of the heat exchanger 72. The upstream end of the water supply pipe 75 is connected to the hot water outlet 62 of the heat source unit 1 via a connecting pipe 76. A hot water outlet pipe 77 is connected to the outlet end of the heat exchanger 72. An external pipe 78 is connected to the downstream end of the hot water outlet pipe 77. A hot water tap 79 is provided on the external pipe 78. A bypass pipe 80 that bypasses the heat exchanger 72 is connected between the water supply pipe 75 and the hot water outlet pipe 77. Upstream of the bypass pipe 80, the water supply pipe 75 is equipped with a flow sensor 81 for detecting water flow, an inlet water temperature sensor 82 for detecting water temperature, and a water flow control valve 83 for controlling the flow rate in the water supply pipe 75. The hot water outlet pipe 77 is equipped with an outlet water temperature sensor 84 for detecting the outlet water temperature. The bypass pipe 80 is equipped with a bypass control valve 85 for controlling the bypass amount. The gas pipe supplying fuel gas to the gas burner 71 is equipped with a main valve, a proportional valve, and a main valve (none of which are shown) from the upstream side.

[0016] The water heater controller 73 consists of a CPU and memory connected to the CPU. The water heater controller 73 is electrically connected to the water volume control valve 83, the bypass control valve 85, the valves of the gas pipe and the igniter for ignition, and a fan (not shown), and controls the operation of each component, and also receives detection signals from each sensor. The water heater controller 73 controls the operation of the water heater 70 according to a program stored in a non-temporary computer-readable storage medium, including memory connected to the CPU, based on the operation commands set by the remote control 74 and each detection signal. The water heater controller 73 is electrically connected to the heat source unit controller 7, enabling them to communicate with each other. The remote control 74 allows the hot water supply system S to be controlled by switches (not shown) to perform both a heat retention operation and a hot water supply operation. The heat retention operation is the operation of the heat pump unit 2 to heat and maintain the temperature of the hot water in the tank body 20. The hot water supply operation is the operation of supplying the hot water in the tank body 20 via the water heater 70.

[0017] In the hot water supply system S configured as described above, when the heat source controller 7 receives an instruction from the remote control 74 to perform a heat retention operation for the heat pump unit 2, it activates the compressor 10 and expansion valve 12 of the heat pump unit 2 and the pump 25 of the tank unit 3. Then, in the heat pump unit 2, the heat transfer medium is compressed by the compressor 10 to become high temperature and high pressure, dissipates heat in the water heat exchanger 11, becomes low temperature and low pressure in the expansion valve 12, and circulates through the circulation path 14 while absorbing heat in the heat absorption section 13. Meanwhile, in the tank unit 3, the operation of the pump 25 causes the hot water in the tank body 20 to circulate through the tank circulation path 28. That is, the hot water circulates from the tank return pipe 22 through the water-side pipe 16 of the water heat exchanger 11 and back to the tank body 20 from the tank supply pipe 21. As a result, heat exchange takes place in the water heat exchanger 11 between the heat transfer medium flowing through the heat-side pipe 15 and the hot water flowing through the water-side pipe 16, heating the hot water in the tank body 20. After the hot water in the tank body 20 is heated to a high temperature (e.g., 75°C), the compressor 10 is controlled ON / OFF based on the temperature detected by the return temperature sensor 27 to maintain a predetermined temperature (e.g., 65°C).

[0018] Then, when hot water operation is selected on the remote control 74, the heat source unit controller 7 opens the second solenoid valve 48 while keeping the first solenoid valve 36 closed, and switches the mixing valve 56 to a state where the first section pipe 55 and the second section pipe 57 are in communication. When the hot water tap 79 is opened in this state, tap water is supplied from the water inlet 38 to the heat source side water supply pipe 5. This tap water is supplied from the second water supply branch pipe 43 to the lower part of the tank body 20. Then, due to this supply pressure, the hot water in the tank body 20 is pushed out into the first section pipe 55 of the heat source side hot water outlet pipe 6, and flows through the mixing valve 56 to the second section pipe 57. The hot water flowing through the second section pipe 57 then flows through the connecting pipe 76 to the water supply pipe 75 of the water heater 70, and is discharged from the hot water tap 79 after passing through the heat exchanger 72, the hot water outlet pipe 77, and the external piping 78.

[0019] If the hot water temperature detected by the hot water temperature sensor 84 is lower than the set temperature set by the remote control 74, the water heater controller 73 opens the main valve and the main valve to ignite the gas burner 71 and heat the hot water passing through the heat exchanger 72. At the same time, based on the inlet water temperature obtained from the inlet water temperature sensor 82, it adjusts the opening of the water volume control valve 83, the bypass control valve 85, and the proportional valve to perform hot water temperature control to match the hot water temperature to the set temperature. On the other hand, if the hot water temperature is higher than the set temperature, the heat source controller 7 switches the mixing valve 56 to a state where the first section pipe 55, the second section pipe 57, and the first water supply branch pipe 42 are in communication, thereby increasing the amount of water supplied from the first water supply branch pipe 42. When the hot water tap 79 is closed and the flow sensor 81 detects that water has stopped flowing through the water heater 70, the water heater controller 73 closes the main valve and the source valve to stop the combustion of the gas burner 71.

[0020] Furthermore, if the heat source unit 1 is not used for an extended period, such as during winter, the water in the tank body 20 is drained. This draining process involves opening the first solenoid valve 36 of the tank drain pipe 4 and opening the pressure relief valve 59 of the pressure relief pipe 58. This pressure relief valve 59 can be opened and closed manually. The following describes the specific structure of the heat source unit 1 and the operation of opening and closing the pressure relief valve 59. Figure 2 is a front view of the heat source unit 1, Figure 3 is a right side view of the heat source unit 1, and Figure 4 is a cross-sectional view taken along line AA of Figure 3. The housing 100 of the heat source unit 1 has a rectangular parallelepiped shape that extends vertically. However, the housing 100 is divided into a cubic frame-shaped upper frame 101 and a lower frame 102. Here, the upper frame 101 and the lower frame 102 are stacked vertically and joined together with bolts to form a single unit. A partition plate 103 is provided on the lower surface of the upper frame 101, and a bottom plate 104 and legs 105, 105 are provided on the lower surface of the lower frame 102. The front, rear, left, right, and top surfaces of the housing 100 are closed off by panels 106. As shown in Figure 3, the front panel 106 has an intake port 107 for outside air from the fan 17 of the heat absorption unit 13. In Figure 2, the front panel 106 is omitted.

[0021] In this configuration, the heat pump unit 2 is housed in the upper frame 101, and the tank unit 3 is housed in the lower frame 102. In the upper frame 101, the heat absorption unit 13 is located on the left side, with the fan 17 facing forward. To the right of the heat absorption unit 13 is the heat source controller 7. To the right of the heat source controller 7 is the water heat exchanger 11. Behind the heat source controller 7 are the compressor 10 and the expansion valve 12. The upper frame 101 is an example of the heating side housing of this disclosure. In the lower frame 102, the tank body 20 is positioned on the left side. The tank body 20 is fixed to the bottom plate 104 via a support base 108 provided on the bottom surface, and fixed to the partition plate 103 via a fitting (not shown) provided on the top surface. The outer periphery of the tank body 20 is covered with an insulating material (e.g., expanded polystyrene) 109. The lower frame 102 is an example of a tank-side housing of the present disclosure. The tank supply pipe 21 is connected to the right side of the tank body 20 and routed upward, passing through the partition plate 103 and entering the upper frame 101, where it is connected to the top of the water heat exchanger 11. The tank return pipe 22 is connected to the center of the bottom of the tank body 20 and routed out to the right side of the tank body 20. The tank return pipe 22 is then routed upward via the pump 25, passing through the partition plate 103 and entering the upper frame 101, where it is connected to the bottom of the water heat exchanger 11.

[0022] A pipe connection section 110 is provided at the bottom of the right-side panel 106 (hereinafter referred to as "106A" for distinction) of the lower frame 102. In addition to a water inlet 38 and a hot water outlet 62, the pipe connection section 110 is equipped with a drain outlet 111 from the pressure relief pipe 58, drain plugs 30, 37, and 47, and a drain outlet 112 from the tank drain pipe 4. Of these, the drain plug 37, which is branched and connected to the branch pipe 4b of the tank drain pipe 4, and the drain outlet 112 from the tank drain pipe 4 are located at the very bottom of the pipe connection section 110. The pipe connection section 110 is covered by a cover 113 attached to panel 106A. The cover 113 has an opening 114 on its rear side, and the pipes and electrical wiring connected to the pipe connection section 110 are routed out to the rear through the opening 114.

[0023] The pressure relief valve 59, located in the pressure relief pipe 58, is positioned on the right side of the lower frame 102, above the cover 113. As shown in Figures 5 and 6, the panel 106A has a window 115 that opens to the right of the pressure relief valve 59. Above the cover 113, the panel 106A has a rectangular recess 116 that extends vertically in a side view, and the window 115 is formed as a slightly smaller rectangular opening at the bottom of the recess 116 in a side view. However, the window 115 is closed by a lid 117 that is substantially the same shape as the recess 116. The lid 117 is attached by locking its upper end in the recess 116 above the window 115 and fixing its lower end in the recess 116 below the window 115 with a screw 118. Therefore, by loosening the screw 118 and removing the lid 117, the pressure relief valve 59 can be exposed through the window 115, as shown in Figure 6. The pressure relief valve 59 is provided with a lever 63 for opening and closing operation. When the pressure relief valve 59 is closed, the lever 63 is in a downward position, extending downward to the right of the pressure relief valve 59, as shown in Figures 5 and 6. From here, as shown in Figure 7, if the lever 63 is rotated to the right to a sideways position, the pressure relief valve 59 will be opened. In this sideways position, the end of the lever 63 protrudes to the right of the outer surface of the panel 106A, passing through the window 115 and the recess 116. The downward position of the lever 63 is an example of the retracted position of the present disclosure, and the sideways position is an example of the protruding position of the present disclosure. Panel 106A is an example of a panel with a window of the present disclosure.

[0024] Therefore, when draining the tank body 20, the worker selects "Start Tank Draining" by operating the heat source controller 7. This opens the first solenoid valve 36 of the tank drain pipe 4. The worker then removes the lid of panel 106A to expose the pressure relief valve 59 and rotates the lever 63 to a sideways position. This opens the pressure relief valve 59. As a result, the water stored in the first section pipe 55 and the pressure relief pipe 58 is discharged to the outside through the drain port 111, and the inside of the tank body 20 is released to the atmosphere. Consequently, the water inside the tank body 20 is discharged to the outside through the tank drain pipe 4 and the drain port 112.

[0025] When the draining of water from the tank body 20 is complete, the first solenoid valve 36 closes. This can be done by having the operator select "Tank water draining complete" using the heat source controller 7, or the heat source controller 7 can automatically close the valve by counting up the pre-set time required for water draining to complete. Next, the worker rotates the lever 63 downwards. This closes the pressure relief valve 59, and the work is completed by screwing the cover 117 into the recess 116. At this time, if the operator forgets to close the valve using lever 63 and attempts to attach the lid 117, the lever 63, in its sideways position, will protrude to the outside of panel 106A through window 115. Therefore, the lid 117 cannot be attached in this state, and the operator must rotate lever 63 to a downward position before attaching the lid 117.

[0026] The heat source unit 1 in the above configuration includes a housing 100, a tank body 20 for storing hot water, a heat pump unit 2 for heating the hot water in the tank body 20, a heat source side water supply pipe 5 connected to a water inlet 38, a heat source side hot water outlet pipe 6 connected between the upper part of the tank body 20 and the hot water outlet 62, to which the downstream end of the heat source side water supply pipe 5 is connected, a mixing valve 56 provided at the connection between the heat source side water supply pipe 5 and the heat source side hot water outlet pipe 6, a pressure relief pipe 58 connected between the upstream end of the heat source side hot water outlet pipe 6 and the mixing valve 56, a pressure relief valve 59 provided on the pressure relief pipe 58 that can be opened and closed manually, a tank drain pipe 4 connected to the lower part of the tank body 20, a first solenoid valve 36 provided on the tank drain pipe 4 that can open and close an internal flow path, and a heat source unit controller 7 that controls the opening and closing of the first solenoid valve 36. The housing 100 is divided into a lower frame 102 that houses at least the tank body 20 and an upper frame 101 that houses at least the heat pump unit 2, with the upper frame 101 placed on top of the lower frame 102 and joined together. The pressure relief pipe 58 and pressure relief valve 59 are provided on the lower frame 102, and by opening the first solenoid valve 36 and the pressure relief valve 59 using the heat source controller 7, it is possible to discharge the hot water from the tank body 20.

[0027] With this configuration, since the manually operated pressure relief valve 59 is provided on the lower frame 102, even if the housing 100 is divided into an upper frame 101 and a lower frame 102, drainage from the tank body 20 can be performed with good operability. In addition, since everything except the heat pump unit 2 and its peripheral equipment can be gathered on the lower frame 102, piping connection work during manufacturing and maintenance becomes easier. In particular, since the tank unit 3 and piping can be separated from the upper heat source controller 7, the risk of water splashing onto the heat source controller 7 is reduced.

[0028] The pressure relief valve 59 has a lever 63 for opening and closing operations. The lever 63 is rotated to a downward position where it is contained within the lower frame 102 when the valve is closed, and to a sideways position where it protrudes from the lower frame 102 when the valve is open. The outer surface of the lower frame 102 is provided with a panel 106A that has a window 115 overlooking the lever 63. The window 115 is provided with an openable and closable cover 117. The lever 63 can be opened and closed through the window 115 when the cover 117 is open, and in the sideways position, it protrudes outward beyond the panel 106A by passing through the window 115. Therefore, the draining operation can be easily performed using the lever 63, and since no solenoid valve is used, the configuration for draining the water is simple. In addition, since the lid 117 cannot be closed by the lever 63 when the pressure relief valve 59 is open, it is possible to reliably prevent forgetting to close the pressure relief valve 59 after draining the water.

[0029] Upstream of the first solenoid valve 36 in the tank drain pipe 4, a branch section 4a is provided, and a branch pipe 4b is connected to the branch section 4a. A drain plug 37, which can be opened manually, is provided at the downstream end of the branch pipe 4b. Therefore, even if the first solenoid valve 36 cannot be opened due to a power outage or malfunction, the water in the tank body 20 can be drained by opening the drain plug 37. The heating means is a heat pump unit 2, and a circulation path 14 is provided between the tank body 20 and the water heat exchanger 11 of the heat pump unit 2 to circulate the hot water in the tank body 20 to the water heat exchanger 11. Therefore, by adopting the heat pump unit 2, running costs are lower and carbon dioxide emissions are reduced compared to heat source equipment that uses fuel gas.

[0030] The following describes examples of changes to this disclosure. The pressure relief valve may be located lower or further back than the configuration described above, as long as it is situated on the tank-side housing. Furthermore, the pressure relief valve is not limited to the right side; it may also be located on the left side or the front side, provided there is no interference with the tank. The lever of the pressure relief valve may be in an upward position when the valve is closed and in a sideways position when the valve is open. Furthermore, the lever is not limited to being operated by rotation in the vertical direction, but may also be operated by rotation in the horizontal direction, so that it is in a forward or backward position when the valve is closed and retracts into the lower housing, and is in a protruding position when the valve is open. The shape of the window is not limited to the rectangular shape described above; it may also be square, circular, or other shapes. The lid may be detachable from the window without using screws. Furthermore, the lid is not limited to being removable from the window; it may also be attached with a hinge mechanism to allow opening and closing. The lid may also be designed to slide left and right or up and down to open and close the window. A detection means may be provided to detect the closed state of the lid. The detection means may be a contact type such as a microswitch or a non-contact type such as a proximity sensor. In this case, if the controller cannot confirm the closed state of the lid by the detection means, it will perform control such as issuing a notification or prohibiting operation. In the above configuration, the solenoid valve is opened by operating the heat source controller to drain the water from the tank. However, opening the solenoid valve is not limited to the heat source controller. For example, it may be done by operating a remote control connected to the controller, or a dedicated controller may be provided with a switch to open and close the solenoid valve.

[0031] The heating method is not limited to a heat pump. The heating method may also be a gas combustion type, such as a water heater. Either the heat source controller or the water heater controller can be omitted, and the entire hot water supply system can be controlled by a single controller. The tank capacity is not limited to 25L as described above; it may be increased or decreased as appropriate. The heat exchanger of a water heater may consist of a primary heat exchanger that recovers sensible heat and a secondary heat exchanger that recovers latent heat. Alternatively, a drop-in pipe connected to the bathtub may be branched off from the hot water outlet pipe of the water heater, and a valve installed in the drop-in pipe may be used to fill the bathtub with hot water. In this case, a bath heating unit may be installed alongside the hot water supply unit so that the water in the bathtub can be reheated by the bath heating unit. The external heat source connected to the hot water outlet is not limited to a water heater. This disclosure is not limited to a hot water supply system consisting of a hot water supply device and an external heat source, but may also apply to configurations in which an external heat source is not connected to the hot water outlet. [Explanation of symbols]

[0032] 1. Heat pump heat source unit, 2. Heat pump unit, 3. Tank unit, 4. Tank drain pipe, 4a. Branch section, 4b. Branch pipe, 5. Heat source side water supply pipe, 6. Heat source side hot water outlet pipe, 7. Heat source unit controller, 14. Circulation path, 20. Tank, 25. Pump, 28. Tank circulation path, 36. First solenoid valve, 38. Water inlet, 42. First water supply branch pipe, 43. Second water supply Branch pipe, 48... Second solenoid valve, 55... First section pipe, 56... Mixing valve, 57... Second section pipe, 58... Pressure relief pipe, 59... Pressure relief valve, 62... Hot water outlet, 63... Lever, 70... Water heater, 100... Housing, 101... Upper frame, 102... Lower frame, 110... Pipe connection, 111, 112... Drain outlet, 115... Window, 117... Cover, 118... Screw, S... Hot water supply system.

Claims

1. A housing equipped with a water inlet and a hot water outlet, A tank for storing hot water, A heating means for heating the hot water in the tank, A water supply pipe connected to the water inlet, A hot water outlet pipe is connected between the top of the tank and the hot water outlet, and the downstream end of the water supply pipe is connected to it. A mixing valve is provided at the connection point between the water supply pipe and the hot water outlet pipe, A pressure relief pipe is connected between the upstream end of the hot water outlet pipe and the mixing valve, A pressure relief valve is provided in the aforementioned pressure relief pipe and can be opened and closed by manual operation, A drain pipe connected to the bottom of the tank, A solenoid valve is provided in the drain pipe and is capable of opening and closing the internal flow path, Includes a controller that controls the opening and closing of the solenoid valve, The housing is divided into at least a tank-side housing that houses the tank and at least a heating-side housing that houses the heating means, and the heating-side housing is mounted on the tank-side housing and joined together. The pressure relief pipe and the pressure relief valve are provided in the tank-side housing, A hot water supply system in which the controller opens the solenoid valve and the pressure relief valve, thereby enabling the discharge of hot water from the tank.

2. The pressure relief valve has a lever for opening and closing, and the lever can be rotated to a retracted position where it is housed within the tank-side housing when the valve is closed, and to a protruding position where it protrudes from the tank-side housing when the valve is open. The outer surface of the tank-side housing is provided with a panel having a window overlooking the lever, and the window is provided with an openable and closable lid. The hot water supply device according to claim 1, wherein the lever can be opened and closed through the window when the lid is open, and in the protruding position, it penetrates the window and protrudes outward from the panel.

3. The hot water supply device according to claim 2, wherein a branch section is provided upstream of the solenoid valve in the drain pipe, a branch pipe is connected to the branch section, and a manually operated drain plug is provided at the downstream end of the branch pipe.

4. The hot water supply device according to any one of claims 1 to 3, wherein the heating means is a heat pump, and a circulation path is provided between the tank and the water heat exchanger of the heat pump for circulating the hot water in the tank between the tank and the water heat exchanger.

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