JP5598025B2 - Hot water storage water heater - Google Patents

Description

  The present invention relates to a hot water storage type hot water supply apparatus, and more particularly to a technique for suppressing the impurity concentration in a hot water storage tank.

  During late-night power hours, water is boiled with an electric water heater or heat pump water heater and stored in a tank. The hot water stored in the tank (high temperature) is mixed with city water (low temperature) as needed to use hot water. Hot water storage type hot water supply equipment is in practical use. In such a technology, the city water is once supplied to the lower part of the hot water storage tank, and the heating part such as an electric water heater or a heat pump type hot water heater is heated and returned to the upper part of the hot water storage tank to continue the process. Hot water is stored inside. And when using warm water, hot hot water is sent out from the hot water storage tank upper part, this is mixed with city water, adjusted to desired temperature, and hot water is supplied.

  When using hot water, the hot water used for hot water supply is always supplied from the upper part of the hot water storage tank. Therefore, impurities such as so-called precipitates of sediment accumulate in the vicinity of the heating part where hot water flows from the bottom of the hot water storage tank or the lower part of the hot water storage tank. When the impurities are deposited, there is a problem that the flow rate from the hot water storage tank to the heating unit is reduced, and the heating efficiency is reduced. Techniques for solving such problems are disclosed in Patent Documents 1-4 listed below.

JP 2008-045821 A JP 2004-332999 A Japanese Utility Model Publication No. 62-156755 Japanese Utility Model Publication No. 5-032965

  For example, in the technique disclosed in Patent Document 1, there is an inlet of a pipe flowing to the heating unit at a position higher than the bottom of the hot water storage tank, and a drain pipe is connected to the bottom. Thereby, the inflow of impurities and the like to the heating unit is avoided, and the accumulated impurities and the like are discharged from the drain pipe. Moreover, in the technique disclosed in Patent Document 2, a cleaning unit is provided in the flow path between the hot water storage tank and the heating unit to perform periodic cleaning. Furthermore, the techniques disclosed in Patent Documents 3 and 4 are drained in a timely manner after accumulating impurities.

  As a means for confirming the accumulation of impurities, for example, in the technique disclosed in Patent Document 3, the electric drain valve provided at the bottom of the hot water storage tank satisfies a drainage condition (time / transparency) for a predetermined time. Open to discharge impurities to the drain. In the technique disclosed in Patent Document 4, a projector and a light receiver are disposed opposite to each other at the bottom of a hot water storage tank, and when the output of the light receiver becomes equal to or less than a predetermined reference value, the light is discharged to a drain pipe.

  Thus, in order to confirm the accumulation of impurities, an apparatus as disclosed in Patent Documents 3 and 4 is necessary, and the manufacturing cost is high. Also, draining hot water in the hot water storage tank together with impurities is not desirable from the viewpoint of saving energy and water resources.

  In view of the above problems, an object of the present invention is to provide a technique for saving energy and water resources while suppressing manufacturing costs in a hot water storage type hot water supply apparatus.

  In order to solve the above problems, a first aspect of a hot water storage type hot water supply apparatus according to the present invention includes a hot water storage tank (2) and a heating unit for heating hot water in the hot water storage tank sucked from a lower part of the hot water storage tank. (4), a pipe (6) through which hot water heated by the heating unit flows to the upper part of the hot water storage tank, and a first water pipe connected to the upper part of the hot water storage tank to send out hot water in the hot water storage tank (8A, 8B), a second water pipe (10) connected to the lowermost part of the hot water storage tank, and a mixed water obtained by mixing hot water fed from each of the first water pipe and the second water pipe. It is a hot water storage type hot water supply apparatus (30a, 30b, 30c) provided with the 3rd water pipe (12A, 12B) to send out.

  The 2nd aspect of the hot water storage type hot water supply apparatus which concerns on this invention is the 1st aspect, Comprising: The water supply pipe | tube (14) which supplies water to the lower part of the said hot water storage tank (2), and branched from the said water supply pipe | tube A fourth water pipe (16, 16a, 16b) connected to the second water pipe (10), and a valve for switching whether or not the water fed from the fourth water pipe flows through the second water pipe. (18B, 18C).

  The 3rd aspect of the hot water storage type hot-water supply apparatus which concerns on this invention is the 2nd aspect, Comprising: The said 3rd water supply pipe | tube (12A, 12B) sends out the said mixed water to a bathtub (20A). (12A) and a faucet hot water supply pipe (12B) for sending the mixed water to the hot water supply faucet (20B), and the mixed water supplied from the bathtub hot water supply pipe is always hot water at the bottom of the hot water storage tank. The mixed water mixed with the hot water supplied from the first water supply pipe (8B) is connected to the water supply pipe (14) in the hot water storage tank (2). When the temperature at the bottom of the tank, which is the temperature of the hot water near the height of the hot water, is equal to or lower than a predetermined threshold value, a mixed water in which the hot water at the bottom of the hot water storage tank and the hot water supplied from the first water supply pipe are mixed is used. When the temperature is higher than the threshold, the fourth transmission And mixed water obtained by mixing the hot water that is water from the first water supply pipe and the water is water from the tube.

  The 4th aspect of the hot water storage type hot water supply apparatus which concerns on this invention is the 2nd or 3rd aspect, Comprising: The operation command to the said valve (18B, 18C) is received from a user, According to the received operation command And a controller (24, 24a) for controlling the operation of the valve.

  According to the 1st aspect of the hot water storage type hot water supply apparatus which concerns on this invention, since the hot water of the lowest part of a hot water storage tank is supplied to hot water supply, the increase in the impurity inside a hot water storage tank can be suppressed. Accordingly, it is possible to avoid or suppress the accumulation of impurities in the heating unit. In addition, the number of operations for cleaning and draining the tank using a cleaning agent can be reduced, which contributes to energy saving and water resource saving. In addition, since accumulation of impurities inside the hot water storage tank can be avoided or suppressed, it is not necessary to provide components related to detection of accumulated impurities, which contributes to cost reduction.

  As water supplied from the water supply pipe, city water having a temperature lower than that of hot water stored in the hot water storage tank is adopted. According to the second aspect of the hot water storage type hot water supply apparatus of the present invention, hot water having a temperature lower than that of the hot water in the lowermost part of the hot water storage tank can be supplied.

  When hot water is filled in the bathtub, the amount of hot water supplied from the bathtub hot water pipe is relatively large. Therefore, even when the hot water temperature immediately after the start of the hot water filling is higher than the hot water set temperature, the hot water from the first water supply pipe and the water from the fourth water supply pipe are appropriately mixed thereafter, so that the hot water filling is completed. The amount of heat in the bathtub can be adjusted to the amount of heat corresponding to the set temperature. On the other hand, the amount of hot water supplied from the faucet hot water supply pipe is relatively small, and the amount of hot water supply is not always set in advance. For this reason, it is difficult to adjust the amount of heat as a whole as in hot water filling. According to the 3rd aspect of the hot water storage type hot water supply apparatus which concerns on this invention, it can respond also when the temperature calculated | required at the time of the hot water supply start from a faucet hot water supply pipe | tube is low.

  According to the 4th aspect of the hot water storage type hot water supply apparatus which concerns on this invention, it can be arbitrarily selected whether the hot water of the lowest part of a hot water storage tank is used for hot water supply.

It is a schematic diagram which shows the piping system of the hot water storage type hot water supply apparatus which concerns on 1st Embodiment of this invention. It is a schematic diagram which shows the piping system of the hot water storage type hot water supply apparatus which concerns on 2nd Embodiment of this invention. It is a schematic diagram which shows the piping system of the hot water storage type hot water supply apparatus which concerns on 3rd Embodiment of this invention.

  Preferred embodiments of the present invention will be described below with reference to the drawings. In the following drawings including FIG. 1, only elements related to the present invention are shown.

<First Embodiment>
As shown in FIG. 1, the hot water storage type hot water supply apparatus 30 a according to the first embodiment of the present invention first includes a hot water storage tank 2, a heating unit 4, and a pipe 6. And the hot water water pipe (equivalent to "the 1st water pipe" in the means for solving a problem) 8A and 8B which sends the hot water in the hot water storage tank 2, and the low temperature water water pipe (means for solving a problem) 10) and a bathtub hot water supply pipe (corresponding to one of the “third water supply pipe” in the means for solving the problem) 12A and a faucet hot water supply pipe (in the means for solving the problem) Equivalent to one of the “third water pipe”) 12B. In addition, 12 A of bathtub hot-water supply pipes and the tap hot-water supply pipe 12B are provided with two or more according to the number of bathtubs and hot-water supply faucets (a kitchen, a washroom, a shower, etc.), respectively.

  The hot water storage tank 2 receives and stores water supplied from the outside such as city water, and stores hot water heated by the heating unit 4. Connected to the lower part of the hot water storage tank 2 is an outgoing pipe 3 that sends hot water in the hot water storage tank 2 to the inlet 4 </ b> A of the heating unit 4. In addition, as for the hot water storage tank 2, for example, the lower part exhibits a hemispherical shape, and it is desirable that the position where the forward pipe 3 is connected is not the bottom of the hot water storage tank 2. This is because impurities are likely to accumulate at the bottom of the hot water storage tank 2, and the impurities may block the outgoing pipe 3, leading to a decrease in flow rate to the heating unit 4, and thus a decrease in heating efficiency.

  For example, a heat pump unit having a pump 5 is employed as the heating unit 4. The hot water in the hot water storage tank 2 supplied from the outward pipe 3 to the inlet 4A is sent out at a predetermined flow rate. Hot water sent out by the pump 5 is heated by exchanging heat with a heat medium such as carbon dioxide in a heating path (not shown) in the heating unit 4. A pipe 6 is connected between the outlet 4 </ b> B of the heating path and the upper part of the hot water storage tank 2. Hot water heated by the heating unit 4 flows through the pipe 6 to the upper part of the hot water storage tank 2.

  That is, the hot water in the hot water storage tank 2 is supplied to the heating unit 4 through the forward pipe 3, and the hot water heated by the heating unit 4 returns to the hot water storage tank 2 through the pipe 6 (hereinafter, the pipe 6 corresponds to the forward pipe 3. Also referred to as “return pipe 6”). Accordingly, in the hot water storage tank 2, relatively hot water is stored in the upper layer portion, and relatively low temperature hot water is stored hierarchically in the lower layer portion.

  The hot water in the hot water storage tank 2 is heated to a predetermined desired temperature by repeating the process in which the hot water in the lower part of the hot water storage tank 2 is heated by the heating unit 4 and circulated to the upper part of the hot water storage tank 2. More specifically, for example, the heating / circulation process until the temperature of the hot water stored in the upper layer of the hot water in the hot water storage tank 2 is 85 degrees Celsius and the temperature of the hot water stored in the lower layer of the hot water storage tank 2 is 60 degrees Celsius. repeat. Whether or not the hot water in the hot water storage tank 2 has been boiled to a predetermined temperature is determined by the temperature detected by a thermistor (not shown) provided on the side surface of the hot water storage tank 2.

  Two high-temperature water water supply pipes 8A and 8B are connected to the upper part of the hot water storage tank 2 to deliver boiling hot water. Hot water sent from one high-temperature water feed pipe 8A is supplied to hot water supplied to the bathtub 20A, and hot water sent from the other high-temperature water feed pipe 8B is supplied to hot water supplied to the hot-water tap 20B. Below, the hot water sent out from the high temperature water pipe 8A, 8B is also simply referred to as “high temperature water”.

  In the hot water storage tank 2, a low temperature water supply pipe 10 is connected to a position lower than the position where the forward path pipe 3 is connected, for example, at the lowermost part. Of the hot water stored in the hot water storage tank 2, the low temperature water pipe 10 is stored at the bottom of the hot water storage tank 2 and sends out relatively low temperature hot water. One end of the low temperature water supply pipe 10 is connected to the lowermost part of the hot water storage tank 2, and the other end of the low temperature water supply pipe 10 is connected to the first mixing valve 9A. The first mixing valve 9A is connected to a hot water supply pipe 8A and a bathtub hot water supply pipe 12A. High temperature water delivered from the high temperature water feed pipe 8A and low temperature hot water delivered from the low temperature water feed pipe 10 (hereinafter also simply referred to as “low temperature water”) are appropriately mixed by the first mixing valve 9A, or low temperature. Only water is selected and sent to the bathtub hot water supply pipe 12A, and hot water is supplied to the bathtub 20A (so-called hot water filling). Here, if the heat amount of the mixed water supplied to the bathtub 20A is grasped by providing a thermometer and a flow meter in the bathtub hot water supply pipe 12A, the hot water temperature and the hot water amount when the hot water filling is completed can be controlled. Note that a thermometer, a flow meter, and a control system that controls the amount of heat of the mixed water supplied to the bathtub 20A are not shown.

  A tank water supply pipe 14 for supplying water to the hot water storage tank 2 from the outside, such as city water, is connected to the lower part of the hot water storage tank 2 (however, a position higher than the position where the low temperature water supply pipe 10 is connected). . Specifically, for example, a tank water supply pipe 14 is connected between the city water supply valve 11 for switching the supply of city water and the lower part of the hot water storage tank 2. In addition, the height (the height from the lowest part of the hot water storage tank 2) where the tank water supply pipe 14 is connected is the same as the height where the forward pipe 3 is connected, or the position where the forward pipe 3 is connected. It is desirable that it is higher than the height of. This is to avoid or suppress the city water supplied from the tank water supply pipe 14 from staying in the lowermost part of the hot water storage tank 2.

  When the hot water storage hot water supply device 30a starts operation, the hot water storage tank 2 is filled with water supplied from the tank water supply pipe. During the subsequent operation, water is appropriately supplied from the tank water supply pipe 14, and the state where the hot water storage tank 2 is filled with hot water is maintained as needed. Therefore, when hot water supply to the bathtub 20A or hot water supply from the hot water supply tap 20B described later is started, city water is supplied from the tank water supply pipe 14 as hot water in the hot water storage tank 2 is consumed. In addition, the hot water supply to the bathtub 20A is started by operation from an operation part (illustration omitted). Moreover, hot water supply from the hot water supply tap 20B is started by operating the knob 21B.

  The hot water filling has a larger amount of hot water supply than the amount of hot water supplied from the hot water supply faucet 20B, such as storing 200 liters of hot water at 42 degrees Celsius in the bathtub 20A. Moreover, the user does not use the supplied hot water until the hot water filling is completed (for example, about 30 minutes). When the hot water in the hot water storage tank 2 has just been boiled, the temperature of the hot water stored in the vicinity of the low temperature water supply pipe 10 reaches 60 degrees Celsius. That is, if hot water is sent out from the low-temperature water pipe 10 in this state, the temperature of the low-temperature water at the start of sending is 60 degrees Celsius. This is unsuitable for hot water filling, but when low-temperature water delivery is started, city water is supplied from the tank water supply pipe 14 in order to fill the hot water storage tank 2 with hot water. The temperature of hot water stored in the lower layer of the water drops. That is, the temperature of the low temperature water also decreases.

  That is, low temperature water is unsuitable for high temperature at the start of hot water filling, but the temperature is lowered to the temperature suitable for hot water filling before the hot water filling is completed. Therefore, low temperature water can be used for hot water filling. A technique for avoiding that hot water of 60 degrees Celsius or more is supplied to the bathtub 20A immediately after the start of hot water filling will be described in a later embodiment.

  When hot water is supplied to the bathtub 20A, a large amount of hot water is stored in the bathtub 20A before use (that is, the hot water supply amount is set in advance). On the other hand, when hot water is supplied from the faucet hot water supply pipe 12B, the amount of hot water used at a time is less than the amount of hot water stored in the bathtub 20A, and the amount of hot water supplied is not set in advance. In addition, when hot water is supplied from the faucet hot water supply pipe 12B, it is often used with running water, and it is difficult to use if the temperature is higher than the expected temperature. Therefore, when hot water is supplied from the faucet hot water supply pipe 12B, it is required that hot water at least at an appropriate temperature (for example, 40 degrees Celsius) or less be supplied immediately after the start of hot water supply.

  Therefore, in addition to the tank water supply pipe 14, one end of a faucet water supply pipe (“fourth water supply pipe” in the means for solving the problem) 16 is connected to the city water supply valve 11. The other end of the faucet water supply pipe 16 is connected to the second mixing valve 9B. A high temperature water supply pipe 8B and a faucet hot water supply pipe 12B are connected to the second mixing valve 9B. High temperature hot water sent from the high temperature water feed pipe 8B and water sent from the tap water supply pipe 16 are appropriately mixed by the second mixing valve 9B and sent to the tap water supply pipe 12B to supply hot water to the hot water tap 20B. Is done. Since the temperature of the water sent out from the faucet water supply pipe 16 (that is, city water) is lower than the temperature of the hot water sent out from the low temperature water water pipe 10, the hot water supply from the hot water supply faucet 20B is controlled by controlling the second mixing valve 9B. Can control the temperature of hot water. Alternatively, only the water sent from the tap water supply pipe 16 may be sent to the tap water supply pipe 12B.

  In addition, the hot water storage hot water supply device 30a is provided with a drain (for example, a low-temperature water pipe) for draining hot water in the hot water storage tank 2 in preparation for cleaning the hot water storage tank 2 or not using the hot water storage hot water supply device 30a for a long period of time. 10 is provided, but is not shown.

  In this way, the low temperature water pipe 10 is connected to the lowermost part of the hot water storage tank 2, and the hot water stored in the lower layer of the hot water storage tank 2 is used for hot water supply to the bathtub 20A, thereby increasing the impurities inside the hot water storage tank 2. Can be suppressed. Therefore, it is possible to avoid or suppress the accumulation of impurities in the heating unit 4. Further, since the number of times of washing and draining the hot water storage tank 2 using a cleaning agent or the like can be reduced, it contributes to energy saving and water resource saving. In addition, since it is not necessary to detect the accumulation of impurities inside the hot water storage tank 2, it is not necessary to provide components related to the detection of accumulated impurities, which contributes to cost reduction.

Second Embodiment
In the said 1st Embodiment, when filling the bathtub 20A, the aspect which always supplies the hot water sent from the low-temperature water water pipe 10 was demonstrated, However, In this embodiment, the filling of the bathtub 20A is carried out as needed. An aspect of providing city water when doing this will be described with reference to the drawings. In addition, about the structure which has the function similar to the structure demonstrated in the said 1st Embodiment, the same code | symbol is attached | subjected to drawing and the description is abbreviate | omitted.

  As shown in FIG. 2, the hot water storage type hot water supply device 30b according to the second embodiment of the present invention includes, for example, a flow path selection valve (for solving the problem) in the hot water storage type hot water supply device 30a shown in the first embodiment. 18B) and a control unit 24 that receives an operation command to the flow path selection valve 18B and controls them.

  A pipe 17 is branched from the faucet water supply pipe 16 between the city water supply valve 11 and the second mixing valve 9B. The pipe 17 is connected to the flow path selection valve 18B. The flow path selection valve 18B is provided between the lowermost part of the hot water storage tank 2 and the first mixing valve 9A in the low-temperature water feed pipe 10. However, here, the low-temperature water water pipe 10 provided between the first mixing valve 9A and the flow path selection valve 18B is grasped as the water pipe 10a. The flow path selection valve 18B switches whether low temperature water is sent to the water supply pipe 10a or city water sent from the faucet water supply pipe 16 is sent. The water supply pipe 10a sends low temperature water or city water sent from the flow path selection valve 18B to the first mixing valve 9A.

  The control unit 24 receives an operation command to the flow path selection valve 18B, and controls the operation of the flow path selection valve 18B according to the received operation command. Specifically, the operation command received by the control unit 24 is whether or not to use low temperature water for filling the bathtub 20A. Whether low temperature water or city water is supplied to the hot water supply to the bathtub 20 </ b> A is received by an operation input to the control unit 24, for example. In FIG. 2, the path (control path) from the control unit 24 to the flow path selection valve 18B is indicated by a broken line so as to be distinguished from the hot water path.

  When the user selects to supply low temperature water to the hot water supply to the bathtub 20A and the control unit 24 receives an operation command corresponding to the selection, the flow path selection valve 18B supplies only the low temperature water to the first mixing valve 9A. Send it out. That is, low temperature water flows through the water pipe 10a. Therefore, in the first mixing valve 9A, the high temperature water and the low temperature water are mixed and sent to the bathtub hot water supply pipe 12A.

  When the user selects that low temperature water is not supplied to the hot water supply to the bathtub 20A and the control unit 24 receives an operation command corresponding to the selection, the flow path selection valve 18B connects the pipe 17 from the faucet water supply pipe 16 to the pipe 17. Only the city water that is sent through is sent to the first mixing valve 9A. That is, city water flows through the water pipe 10a. Therefore, in the first mixing valve 9A, the high-temperature water and city water are mixed and sent out to the bathtub hot water supply pipe 12A. The flow path selection valve 18B may send both city water sent from the faucet water supply pipe 16 through the pipe 17 and low temperature water to the first mixing valve 9A.

  As described above, if the flow path selection valve 18B is provided, low temperature water can be supplied to the bathtub 20A. Moreover, since the control part 24 is provided, it can be arbitrarily selected whether low temperature water is used for hot water supply.

<Third Embodiment>
In the first and second embodiments, the mode in which the low-temperature water is supplied only to the hot water filling of the bathtub 20A has been described. While explaining.

  As shown in FIG. 3, the hot water storage type hot water supply device 30c according to the third embodiment of the present invention includes, for example, a channel selection valve 18C and a channel selection valve in the hot water storage type hot water supply device 30a shown in the first embodiment. A control unit 24a that receives and controls an operation command to 18C and a temperature detection unit 22 are further provided. However, instead of the tap water supply pipe 16 of the first embodiment, a first tap water supply pipe 16a and a second tap water supply pipe 16b are provided. The flow path selection valve 18C is provided between the lowest part of the hot water storage tank 2 and the first mixing valve 9A in the low-temperature water feed pipe 10. However, here, the low temperature water pipe 10 provided between the flow path selection valve 18C and the first mixing valve 9A is grasped as the water pipe 10b.

  The first faucet water supply pipe 16a has one end connected to the city water supply valve 11 and the other end connected to the flow path selection valve 18C. The flow path selection valve 18C sends low-temperature water or city water to the water pipe 10b. Hot water (low temperature water or city water) sent from the water supply pipe 10b is sent to the second faucet water supply pipe 16b and / or the first mixing valve 9A. The second faucet water supply pipe 16b sends out hot water branched and sent from the water supply pipe 10b to the second mixing valve 9B. Thereby, low temperature water or city water can be sent out to both the 1st and 2nd mixing valves 9A and 9B.

  The temperature detection unit 22 employs, for example, a thermocouple, platinum resistance, or the like, and detects a tank lower temperature that is a temperature of hot water stored in the lower part of the hot water storage tank 2. Specifically, the tank lower temperature is the temperature of hot water near the height of the hot water storage tank 2 where the water supply pipe 14 is connected. Here, the temperature of the low temperature water is lower than the temperature of the hot water near the water supply pipe 14. The detected tank lower part temperature is transmitted to the control unit 24a. The control unit 24a receives an operation command to the flow path selection valve 18C, and controls the operation of the flow path selection valve 18C according to the received operation command. In particular, the operation of the flow path selection valve 18C is controlled after comparing the tank lower part temperature detected by the temperature detection unit 22 with a predetermined threshold value. Specifically, as the threshold value, the temperature of the hot water that the user wants to send out from the hot water tap 20B (hereinafter also referred to as “temperature threshold value”. The temperature threshold value is, for example, 40 degrees Celsius, and does not exceed the temperature of the hot water. If the temperature of the low temperature water is equal to or lower than the temperature threshold, the low temperature water is also supplied to the hot water supply from the hot water supply faucet 20B. The temperature threshold value may be a predetermined fixed value or a movable value that can be arbitrarily set.

  More specifically, when the hot water supply from the hot water supply tap 20B is started when the temperature of the low temperature water is equal to or lower than the temperature threshold, the flow path selection valve 18C sends the low temperature water to the second tap water supply pipe 16b. . Therefore, in the 2nd mixing valve 9B, high temperature water and low temperature water are mixed and it sends out to faucet hot water supply pipe | tube 12B. By controlling the mixing ratio in the second mixing valve 9B, hot water at a temperature between the temperature of the high temperature water and the temperature of the low temperature water is supplied from the hot water supply tap 20B.

  Only using high temperature water and low temperature water cannot supply hot water having a temperature below the temperature threshold. Therefore, when the hot water supply from the hot water supply faucet 20B is requested when the temperature of the low-temperature water is higher than the temperature threshold (specifically, when the knob 21B is operated), the flow path selection valve 18C sets the first faucet water supply. The city water sent from the pipe 16a is sent to the second mixing valve 9B through the water pipe 10b. Therefore, in the second mixing valve 9B, hot water and city water (or even cold water) are mixed and hot water is supplied from the hot water supply tap 20B.

  When hot water is supplied to the bathtub 20A during hot water supply from the hot water supply tap 20B, for example, the operation differs depending on the temperature of the low temperature water. When the temperature of the low-temperature water is equal to or lower than the temperature threshold (that is, when low-temperature water is supplied to the hot water supply from the hot water supply faucet 20B), the low-temperature water is supplied to both the hot water supply from the hot water supply faucet 20B and the hot water supply to the bathtub 20A.

  When hot water is supplied from the hot water supply tap 20B when the temperature of the low-temperature water is higher than the temperature threshold and hot water is supplied to the bathtub 20A during the hot water supply, for example, until the hot water supply from the hot water supply tap 20B is finished, City water is sent out to both of the faucet water supply pipes 16b. And after the hot water supply from hot water supply tap 20B is complete | finished, low temperature water is sent out to 9 A of 1st mixing valves. Specifically, the flow path selection valve 18C sends low-temperature water sent from the low-temperature water water pipe 10 to the water pipe 10b.

  Moreover, when hot water is filled in the bathtub 20A, the amount of hot water supplied from the bathtub hot water supply pipe 12A is relatively large. Therefore, even when the hot water temperature is higher than the hot water set temperature immediately after the start of hot water filling, hot water filling is performed by appropriately mixing hot water from the high temperature water supply pipe and city water from the first faucet water supply pipe 16a thereafter. When completed, the amount of heat in the bathtub 20A can be adjusted to the amount of heat corresponding to the desired hot water temperature. On the other hand, the amount of hot water supplied from the faucet hot water supply pipe 12B should not be adjusted as a whole of the amount of hot water supplied in one hot water supply, and a desired temperature is required at each time point (in real time). . According to the above configuration, when the temperature required at the start of hot water supply from the faucet hot water supply pipe 12B is higher than the temperature of the low temperature water, low temperature water can be supplied to the hot water supplied from the hot water tap 20B. If low temperature water is supplied to the hot water supply from the hot water supply tap 20B, for example, even when the shower 20 is used without using the bathtub 20A in the summer, the low temperature water is supplied to the hot water supply from the shower hot water supply tap (not shown). Can be provided. Accordingly, accumulation of impurities in the hot water storage tank 2 can be avoided or suppressed.

2 Hot water storage tank 4 Heating section 6 Piping (return pipe)
8A, 8B 1st water pipe (high temperature water pipe)
10 Second water pipe (low temperature water pipe)
12A, 12B 3rd water pipe (tub hot water pipe and faucet hot water pipe)
14 Water supply pipe (tank water supply pipe)
16, 16a, 16b 4th water pipe (faucet water supply pipe)
18B, 18C valve (flow path selection valve)
20A Bathtub 20B Hot water tap 24, 24a Control unit 30a, 30b, 30c Hot water storage type hot water supply device

Claims (4)

A hot water storage tank (2),
A heating unit (4) for heating hot water in the hot water storage tank sucked from the lower part of the hot water storage tank;
A pipe (6) in which hot water heated by the heating section flows to an upper part of the hot water storage tank;
A first water pipe (8A, 8B) connected to the upper part of the hot water storage tank for sending hot water in the hot water storage tank;
A second water pipe (10) connected to the lowermost part of the hot water storage tank;
A hot water storage type hot water supply device (30a, 30b, 30c) comprising a third water supply pipe (12A, 12B) for sending mixed water mixed with hot water supplied from each of the first water supply pipe and the second water supply pipe. . A water supply pipe (14) for supplying water to the lower part of the hot water storage tank (2);
A fourth water pipe (16, 16a, 16b) branched from the water pipe and connected to the second water pipe (10);
A valve (18B, 18C) for switching whether or not to flow water supplied from the fourth water pipe to the second water pipe;
The hot water storage type hot water supply device (30a, 30b, 30c) according to claim 1. The third water pipe (12A, 12B)
A bathtub hot water supply pipe (12A) for sending the mixed water to the bathtub (20A);
A faucet hot water supply pipe (12B) for sending the mixed water to the hot water faucet (20B),
The mixed water supplied from the bathtub hot water supply pipe is always a mixed water in which the hot water at the bottom of the hot water storage tank and the hot water supplied from the first water supply pipe (8B) are mixed,
The mixed water supplied from the faucet hot water supply pipe has a tank lower temperature which is the temperature of hot water near the position where the water supply pipe (14) is connected in the hot water storage tank (2) below a predetermined threshold value. When the temperature is higher than the threshold, the water supplied from the fourth water supply pipe is a mixed water in which the hot water at the bottom of the hot water storage tank and the hot water supplied from the first water supply pipe are mixed. A mixed water mixed with hot water fed from the first water pipe,
The hot water storage type hot water supply device (30c) according to claim 2. A control unit (24, 24a) that receives an operation command to the valve (18B, 18C) from a user and controls the operation of the valve according to the received operation command;
The hot water storage type hot water supply device (30b, 30c) according to claim 2 or claim 3.

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