Hot water supply system

Abstract

Even when a bottom section of the hot water outlet pipe is formed where water cannot be drained, the hot water outlet pipe can be drained effectively. [Solution] The heat pump heat source unit 1 includes a tank body 20, a heat pump unit 2, a heat source side hot water outlet pipe 6, a heat source side water supply pipe 5, a housing 100, and a pipe connection section 110. The pipe connection section 110 is located at the bottom of the housing 100, and the mixing valve 56 is located above the pipe connection section 110. The first section 55 of the heat source side hot water outlet pipe 6 has an inner pipe section 116 that is connected to the tank body 20 at a position below the mixing valve 56 and whose downstream end bends upward, and an outer pipe section 117 that is connected to the inner pipe section 116, extends horizontally to the outside of the tank body 20, then bends upward and is connected to the mixing valve 56. A drain pipe 63 for the hot water outlet is connected to the lowest part of the outer pipe section 117, and the downstream end of the drain pipe 63 is connected to a drain plug 64 for the hot water outlet provided on the pipe connection section 110 at a position below the lowest part.

Description

Technical Field

[0001] The present disclosure relates to a hot water supply device that heats water using a heating means such as a heat pump, stores the heated 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 heated 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 supply machine including a heat pump unit and a hot water storage device. In this hot water storage device, inside a casing (housing), there are provided a tank, a water supply pipe for supplying raw water to the tank, a hot water supply pipe (hot water discharge pipe) for discharging hot water in the tank, a mixing valve for mixing the raw water in the water supply pipe and the hot water in the hot water supply pipe, and a drain pipe for discharging the hot water and water in the tank. At the lower part of the casing, there are provided joints (connection ports) for connecting each pipe and a drain port of the drain pipe.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above hot water supply machine, when the connection ports and drain ports of each pipe are concentrated and arranged at the lower part, the surplus space at the lower part inside the casing becomes less, so each valve including the mixing valve is arranged above the arrangement space of the connection port inside the casing. On the other hand, when minimizing the height of the casing to make it more compact, the tank is formed to the full height of the casing's interior dimensions in order to secure the necessary capacity, so the hot water outlet pipe is connected to the tank's body for easier connection. In this case, the hot water outlet pipe drawn from the tank is bent upward toward the mixing valve located above the connection point to the tank, while the end of the hot water outlet pipe inside the tank is bent upward to dispense the hotter water from the upper part. As a result, the bottom of the hot water outlet pipe is formed in a way that prevents draining, and there is a risk of the hot water outlet pipe being damaged by freezing in winter.

[0005] Therefore, the present disclosure aims to provide a hot water supply system that allows for efficient draining of the hot water outlet pipe even when a bottom section of the outlet pipe is formed that cannot be drained. [Means for solving the problem]

[0006] To achieve the above objective, this disclosure provides a hot water supply system comprising a tank for storing hot water, A heating means for heating the hot water in the tank, A hot water outlet pipe for discharging hot water from the tank, A water supply pipe is connected to the hot water outlet pipe via a mixing valve and supplies tap water to the hot water outlet pipe, A housing that accommodates the aforementioned tank and each of the pipes, The housing includes a pipe connection section to which each of the pipes is connected, The aforementioned piping connection section is located at the bottom of the housing, The mixing valve is positioned above the pipe connection portion within the housing. Furthermore, the hot water outlet pipe includes a first section connected to the upstream side of the mixing valve and a second section connected to the downstream side of the mixing valve, and the first section has an inner pipe section that is horizontally connected to the tank at a position below the mixing valve and protrudes into the tank, then bends upward so that its upstream end opens into the tank, and an outer pipe section that is connected to the inner pipe section and extends horizontally to the outside of the tank, then bends upward so that its downstream end is connected to the mixing valve. A drain pipe for the hot water outlet pipe is connected to the lowest part of the outer pipe section, and the downstream end of the drain pipe for the hot water outlet pipe is connected to a drain plug provided at the pipe connection section at a position lower than the lowest part. [Effects of the Invention]

[0007] According to this disclosure, since a drain pipe for the hot water outlet pipe is connected to the lowest part of the outer pipe section of the first section pipe, water can be drained from a drain plug provided at the pipe connection. Therefore, even if a lowest part of the hot water outlet pipe is formed where water cannot be drained, the hot water outlet pipe can be drained effectively. [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 (side panels are omitted). [Figure 4] This is a cross-sectional view along line AA in Figure 3. [Figure 5] Figure 3 is a cross-sectional view along line BB. [Figure 6] Figure 5 is a cross-sectional view along the CC line. [Modes for carrying out the invention]

[0009] The embodiments of this disclosure will be described below with reference to the drawings. Figure 1 is a schematic diagram showing a hot water supply system S consisting of a heat pump heat source unit (hereinafter simply referred to as "heat source unit") 1, which is an example of a hot water supply device of this disclosure, and a water heater 70 connected to the heat source unit 1. The heat source unit 1 comprises 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 outlet pipe 6, and a heat source unit controller 7. The heat pump unit 2 comprises a compressor 10, a water heat exchanger 11, an expansion valve 12, a heat absorption section 13, and a loop-shaped circulation path 14 connecting these in series. A heat transfer medium (e.g., a refrigerant substitute) can circulate through the circulation path 14. The compressor 10 compresses the heat transfer medium absorbed in the heat absorption section 13, making it high temperature and high pressure, and sends it to the water heat exchanger 11. The water heat exchanger 11 is equipped with a heat-side pipe 15 and a water-side pipe 16. The heat-side pipe 15 is incorporated into the circulation path 14. The water-side pipe 16 is incorporated into the tank circulation path 28, which will be described later. The expansion valve 12 depressurizes the heat transfer medium from which heat has been removed in the water heat exchanger 11, making it low temperature and low pressure, and sends it to the heat absorption section 13. The heat absorption section 13 has a fan 17 and performs heat exchange between the outside air and the heat transfer medium.

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

[0011] The drain pipe 4 for the tank is connected to the lowermost part of the tank body 20. The drain pipe 4 for the tank is provided with a throttle portion 35 for flow control and a first solenoid valve 36 for opening and closing the flow path in order from the upstream side. A branch portion 4a is provided between the throttle portion 35 and the first solenoid valve 36, and a branch pipe 4b is connected to the branch portion 4a. A drain plug 37 for the branch pipe is provided at the outlet of the branch pipe 4b. The water supply pipe 5 on the heat source side has its upstream end connected to a water inlet 38 provided in the housing. An external water pipe (not shown) is connected to the water inlet 38. The water supply pipe 5 on the heat source side is provided 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 water flow rate, and a heat source side inlet water temperature sensor 41 for detecting the water temperature from the upstream side.

[0012] Downstream of the heat source side inlet water temperature sensor 41, the water supply pipe 5 on the heat source side 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 (to be described later) provided in the heat source side hot water supply pipe 6. The first water supply branch pipe 42 is provided with a check valve 44 and a throttle portion 45 for flow control. A drain pipe 46 for the water supply pipe is connected between the check valve 44 and the throttle portion 45. A drain plug 47 for the water supply pipe is provided at the downstream end of the drain pipe 46 for the water supply pipe. The second water supply branch pipe 43 is connected to the lowermost part of the tank body 20. The second water supply branch pipe 43 is provided with a second solenoid valve 48 for opening and closing the flow path and a check valve 49 from the upstream side.

[0013] The heat source side hot water supply pipe 6 includes a first partial pipe 55, a mixing valve 56, and a second partial pipe 57. The upstream end of the first partial pipe 55 is connected to the upper part of the tank body 20, and the downstream end is connected to the first inlet of the mixing valve 56. A pressure relief pipe 58 is connected to the first partial pipe 55. A pressure relief valve 59 is provided in the pressure relief pipe 58. An upstream temperature sensor 60 for detecting the hot water temperature in the first partial pipe 55 is provided in the first partial pipe 55 downstream of the pressure relief pipe 58. The mixing valve 56 is an electric type that drives the valve body by a motor within the flow path of the T-port, enabling adjustment of the opening degree of the flow path along with switching 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 partial pipe 57 is connected to the outlet of the mixing valve 56. A downstream temperature sensor 61 for detecting the outlet water temperature in the second partial pipe 57 is provided on the second partial pipe 57. A hot water outlet 62 is provided at the downstream end of the second partial pipe 57. An outlet water pipe drain pipe 63 is connected to the first partial pipe 55 upstream of the mixing valve 56. An outlet water pipe drain plug 64 is provided at the downstream end of the outlet water pipe drain pipe 63.

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

[0015] The water heater 70 has a gas burner 71, a heat exchanger 72, a water heater controller 73, and a remote controller 74. A water supply pipe 75 is connected to the inlet end of the heat transfer pipe 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 machine 1 via the connection 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 supply pipe 21 through the water-side pipe 16 of the heat exchanger 11 and back to the tank body 20 through the return pipe 22. As a result, heat exchange takes place in the 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 supply 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] Next, the specific structure of the heat source unit 1 will be described. Figure 2 is a front view of the heat source unit 1. Figure 3 is a side view of the heat source unit 1, Figure 4 is a cross-sectional view along line AA of Figure 3, Figure 5 is a cross-sectional view along line BB of Figure 3, and Figure 6 is a cross-sectional view along line CC of Figure 5. 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. 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. In the lower frame 102, the tank body 20 is positioned on the left side. The lower part of the tank body 20 is fixed to the bottom plate 104 via a support base 107. The upper part of the tank body 20 is fixed to the partition plate 103 via an upper support bracket 108. The outer perimeter of the tank body 20 is covered with insulation material 109. The insulation material 109 is made of, for example, expanded polystyrene. The supply pipe 21 is branched and connected to the tank drain pipe 4, which is connected to the center of the bottom surface of the tank body 20, and its upstream end is shared with the tank drain pipe 4. The supply pipe 21 is drawn out to the right side of the tank body 20, routed upward via the pump 25, passes through the partition plate 103 and enters the upper frame 101, and is connected to the lower part of the water heat exchanger 11. The return pipe 22 is connected to the right side of the tank body 20 and routed upward, passes through the partition plate 103 and enters the upper frame 101, and is connected to the upper part of the water heat exchanger 11.

[0022] A pipe connection section 110 is provided at the bottom of the right-side panel 106 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 a pressure relief pipe 58, drain plugs 30, 37, 47, and 64, and a drain outlet 112 from the tank drain pipe 4. Of these, the branch pipe 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 hot water outlet pipe drain plug 64 is located below the water supply pipe drain plug 47. The pipe connection section 110 is covered by a cover 113 attached to the panel 106. The cover 113 has an opening 114 on its rear side, and external piping and electrical wiring connected to the pipe connection section 110 are routed out to the rear through the opening 114. In this way, each pipe is brought together and connected to the pipe connection section 110 at the bottom of the lower frame 102, so that the mixing valve 56 is located in the upper part of the lower frame 102 and above the cylindrical body 20a of the tank body 20.

[0023] The first section 55 of the heat source side outlet pipe 6 penetrates the body 20a of the tank body 20 in the left-right direction. The first section 55 consists of a joint pipe section 115, an inner pipe section 116, and an outer pipe section 117. The joint pipe section 115 is attached to the body 20a and protrudes radially outward, penetrating the insulation material 109 and the body 20a. The inner pipe section 116 is connected to the inner end of the joint pipe section 115 within the tank body 20 and extends horizontally radially inward of the tank body 20, then bends upward in the center of the tank body 20, forming an L-shape in front view. The upstream end of the upwardly protruding inner pipe section 116 opens above the body 20a. In the inner pipe section 116, a communication hole 118, which is an elongated hole extending left and right, is formed on the lower surface of the horizontal portion. The lowermost part of the inner pipe section 116 is in communication with the inside of the tank body 20 through the communication hole 118. The outer pipe section 117 is connected to the outer end of the joint pipe section 115, extends horizontally radially outward from the tank body 20, then bends upward and is connected to the mixing valve 56. The hot water outlet drain pipe 63 is connected to the lower part of the horizontal section of the outer pipe section 117 and extends downward, and is connected to the hot water outlet drain plug 64 of the piping connection section 110.

[0024] Therefore, when draining the water from the tank body 20, the remote control 74 is operated to command the heat source controller 7 to drain the water, and the heat source controller 7 opens the first solenoid valve 36. Then, the hot water in the tank body 20 is discharged to the outside through the drain port 112 via the tank drain pipe 4. At this time, the hot water in the horizontal portions of the inner pipe section 116 and outer pipe section 117 of the first branch pipe 55 is discharged into the tank body 20 via the communication hole 118, so that no hot water remains in the first branch pipe 55. If the first solenoid valve 36 malfunctions or does not open, the water in the tank body 20 can be drained from the branch pipe drain plug 37 by manually opening the branch pipe drain plug 37 of the branch pipe 4b at the piping connection section 110. On the other hand, by manually opening the hot water outlet drain valve 64 at the pipe connection section 110, the hot water in the horizontal sections of the inner pipe section 116 and outer pipe section 117 of the first section pipe 55 can be discharged to the outside through the hot water outlet drain valve 64 via the hot water outlet drain pipe 63.

[0025] (Effect of disclosing the formation of a communication hole at the lowest part of the inner tube section) The heat source unit 1 in the above configuration includes a tank body 20 (tank) for storing hot water, a heat pump unit 2 (heating means) for heating the hot water in the tank body 20, a heat source side outlet pipe 6 (outlet pipe) for discharging the hot water from the tank body 20, a heat source side water supply pipe 5 (water supply pipe) connected to the heat source side outlet pipe 6 via a mixing valve 56 and supplying tap water to the heat source side outlet pipe 6, a tank drain pipe 4 (drain pipe) for discharging the hot water from the tank body 20, a housing 100 that houses the tank body 20 and each pipe, and a pipe connection section 110 provided in the housing 100 to which each pipe is connected. The piping connection section 110 is located at the bottom of the housing 100, while the mixing valve 56 is located above the piping connection section 110 within the housing 100. The heat source side outlet pipe 6 consists of a first section pipe 55 connected to the upstream side of the mixing valve 56 and a second section pipe 57 connected to the downstream side of the mixing valve 56. The first section pipe 55 has an inner pipe section 116 that is horizontally connected to the tank body 20 at a position below the mixing valve 56, protrudes into the tank body 20, then bends upward so that its upstream end opens into the tank body 20, and an outer pipe section 117 that is connected to the inner pipe section 116, extends horizontally to the outside of the tank body 20, then bends upward so that its downstream end is connected to the mixing valve 56. A communication hole 118 that communicates with the inside of the tank body 20 is formed at the lowest part of the inner pipe section 116.

[0026] With this configuration, a communication hole 118 is formed at the bottom of the inner pipe section 116. Therefore, when draining the tank body 20, the hot water in the inner pipe section 116 is discharged through the communication hole 118 along with the hot water in the tank body 20. Thus, even if the bottom of the heat source side outlet pipe 6 is formed where draining is not possible, the water in the heat source side outlet pipe 6 can be drained effectively.

[0027] The disclosure of forming a communication hole at the lowest part of the inner tube section can be modified as follows: The shape of the communication holes in the inner tube can be modified as appropriate, provided that water drainage is possible. There may be multiple communication holes. The inner pipe section is not limited to being bent straight up (90°) in the center of the tank body. The bending angle may be obtuse or acute with respect to the horizontal section. In the above configuration, the first section of the pipe is formed by connecting the inner pipe section and the outer pipe section at the joint pipe section. However, the joint pipe section may be omitted, and the inner pipe section and the outer pipe section may be directly connected. Alternatively, the inner pipe section and the outer pipe section may be formed integrally. Depending on the installation position of the tank body within the enclosure, the first section of the pipe may be connected to the tank body in reverse (left-right or right-back) or front-to-back. In this disclosure, it is not necessary to provide a drain pipe for the hot water outlet pipe in the outer pipe section.

[0028] (Effect of disclosing the connection of a drain pipe for the hot water outlet pipe to the lowest part of the outer pipe section) The heat source unit 1 in the above configuration includes a tank body 20 (tank) for storing hot water, a heat pump unit 2 (heating means) for heating the hot water in the tank body 20, a heat source side outlet pipe 6 (outlet pipe) for discharging the hot water from the tank body 20, a heat source side water supply pipe 5 (water supply pipe) connected to the heat source side outlet pipe 6 via a mixing valve 56 and supplying tap water to the heat source side outlet pipe 6, a housing 100 for housing the tank body 20 and each pipe, and a pipe connection section 110 provided in the housing 100 to which each pipe is connected. The piping connection section 110 is located at the bottom of the housing 100, while the mixing valve 56 is located above the piping connection section 110 within the housing 100. The heat source side outlet pipe 6 consists of a first section pipe 55 connected to the upstream side of the mixing valve 56 and a second section pipe 57 connected to the downstream side of the mixing valve 56. The first section pipe 55 has an inner pipe section 116 that is horizontally connected to the tank body 20 at a position below the mixing valve 56, protrudes into the tank body 20, then bends upward so that its upstream end opens into the tank body 20, and an outer pipe section 117 that is connected to the inner pipe section 116, extends horizontally to the outside of the tank body 20, then bends upward so that its downstream end is connected to the mixing valve 56. Furthermore, a drain pipe 63 for the hot water outlet pipe is connected to the lowest part of the outer pipe section 117, and the downstream end of the drain pipe 63 for the hot water outlet pipe is connected to a drain valve 64 (drain valve) for the hot water outlet pipe, which is located at a position lower than the lowest part of the outer pipe section 110.

[0029] With this configuration, since the drain pipe 63 for the hot water outlet pipe is connected to the lowest part of the outer pipe section 117, water can be drained from the drain plug 64 for the hot water outlet pipe provided at the pipe connection section 110. Therefore, even if a lowest part is formed in the heat source side hot water outlet pipe 6 where water cannot be drained, the water in the heat source side hot water outlet pipe 6 can be drained effectively.

[0030] Regarding the disclosure of connecting a drain pipe for the hot water outlet pipe to the lowest part of the outer pipe section, the following modifications are possible. The connection position of the drain pipe for the hot water outlet pipe is not limited to the above configuration, as long as it is at the lowest point of the outer pipe section. Similarly, the position of the drain valve for the hot water outlet pipe is not limited to the above configuration, as long as it is located below the lowest point of the outer pipe section. Depending on the installation position of the tank body within the enclosure, the first section of the pipe may be connected to the tank body in reverse (left-right or right-back) or front-to-back. In this disclosure, it is not necessary to provide a communication hole at the lowest part of the inner tube.

[0031] The following describes examples of changes common to each disclosure. The heating means is not limited to a heat pump. The heating means may also be a gas combustion type, such as a water heater. In this case, the housing does not have to be divided vertically into the heating means side and the tank side; it may be divided horizontally, or the heating means and the tank may be housed in a single housing. 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, 20a. Body section, 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... Drain pipe for hot water outlet, 64... Drain plug and lever for hot water outlet, 70... Water heater, 100... Housing, 101... Upper frame, 102... Lower frame, 103... Partition plate, 104... Bottom plate, 109... Insulation material, 110... Pipe connection section, 115... Joint pipe section, 116... Inner pipe section, 117... Outer pipe section, 118... Communication hole, S... Hot water supply system.

Claims

[Claim 1] A tank for storing hot water, A heating means for heating the hot water in the tank, A hot water outlet pipe for discharging hot water from the tank, A water supply pipe is connected to the hot water outlet pipe via a mixing valve and supplies tap water to the hot water outlet pipe, A housing that accommodates the aforementioned tank and each of the pipes, The housing includes a pipe connection section to which each of the pipes is connected, The aforementioned piping connection section is located at the bottom of the housing, The mixing valve is positioned above the pipe connection portion within the housing, The hot water outlet pipe includes a first section connected to the upstream side of the mixing valve and a second section connected to the downstream side of the mixing valve, and the first section has an inner pipe section that is horizontally connected to the tank at a position below the mixing valve and protrudes into the tank, then bends upward so that its upstream end opens into the tank, and an outer pipe section that is connected to the inner pipe section and extends horizontally to the outside of the tank, then bends upward so that its downstream end is connected to the mixing valve. A hot water supply device in which a drain pipe for the hot water outlet pipe is connected to the lowest part of the outer pipe section, and the downstream end of the drain pipe for the hot water outlet pipe is connected to a drain plug provided at the pipe connection section at a position lower than the lowest part.

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