Hot water storage type water heater

Abstract

To prevent unnecessary air bleeding operation.SOLUTION: In a hot water storage type water heater including a water supply temperature sensor 49 for detecting a water supply temperature, a heat temperature sensor for detecting a heat temperature of water boiled by heating means 18, a pressure reducing valve 26 provided in the middle of a water supply pipe 6 to adjust a water supply pressure, and control device 34 for controlling an air bleeding operation of sending air accumulated in a hot water storage tank 2 together with hot water supply to the outside of the hot water storage tank 2 during hot water supply operation, the control device 34 is provided with determination means 38 for determining whether the air bleeding operation is necessary on the basis of the water supply temperature, and the heat temperature or target temperature, and the control device 34 executes the air bleeding operation during hot water supply in the case that the determination means 38 determines that the air bleeding operation is necessary, and prevents the air bleeding operation from being executed in the case that the determination means 38 determines that the air bleeding operation is unnecessary.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This invention relates to a storage water heater equipped with heating means.

Background Art

[0002] Conventionally, in this type of storage water heater, a storage tank and heating means are provided, and a heating forward pipe that sends water from the lower part of the storage tank to the heating means and a heating return pipe that sends water from the heating means to the storage tank are used to connect the storage tank and the heating means to form a heating circulation circuit. A circulation pump provided in the heating circulation circuit circulates the hot water in the storage tank and the heating means to heat the water in the storage tank. The heated hot water is stored in the storage tank, and hot water at a set temperature is supplied while sequentially mixing the high-temperature water and the supply water in the storage tank to achieve economical hot water supply.

[0003] Also, by arranging a pressure relief valve that opens when the pressure in the storage water heater exceeds a predetermined pressure at a position where cold water flows, when discharging the pressure outside the storage water heater, cold water is discharged, so it has been known to prevent the high-temperature water stored in the storage tank from being discharged outside the storage water heater (for example, Patent Document 1).

[0004] Also, in order to release the air accumulated in the storage tank to the hot water supply use terminal, it has been known to open the high-temperature side of the opening degree of the medium-temperature water mixing valve to facilitate air escape (for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, by arranging a pressure relief valve in the water supply pipe as in Patent Document 1, it is possible to prevent the discharge of high-temperature water when the pressure in the hot water storage tank becomes high during the boiling operation. However, since the pressure relief valve is arranged at the lower part of the hot water storage tank, there is a problem that it is impossible to discharge the air that has been discharged together with the pressure that accumulates in the upper part of the hot water storage tank.

[0007] Also, as in Patent Document 2, regardless of the presence or absence of air accumulated in the upper part of the hot water storage tank, if the high-temperature side of the opening degree of the medium-temperature water mixing valve is opened during hot water supply, when there is no air accumulated in the upper part of the hot water storage tank, the consumption of medium-temperature water is reduced accordingly. However, if there is still medium-temperature water during the boiling operation, there is a problem that the boiling efficiency will decrease.

Means for Solving the Problems

[0008] According to the present invention, in a hot water storage type water supply device including a hot water storage tank for storing hot water, heating means for boiling the hot and cold water in the hot water storage tank to a target temperature, high-temperature water taken out from the upper part of the hot water storage tank, a medium-temperature water mixing valve for mixing the high-temperature water taken out from the upper part of the hot water storage tank and the medium-temperature water taken out from the middle part of the hot water storage tank, a water supply pipe connected to the lower part of the hot water storage tank for supplying water to the hot water storage tank, water supply temperature detection means for detecting the water supply temperature, heating temperature detection means for detecting the heating temperature of the water boiled by the heating means, a pressure reducing valve provided in the middle of the water supply pipe for adjusting the water supply pressure, and a control device for controlling an air venting operation of opening the opening degree of the high-temperature water side of the medium-temperature water mixing valve wide to send out the air accumulated in the hot water storage tank to the outside of the hot water storage tank together with the hot water supply during the hot water supply operation, the control device is provided with determination means for determining the necessity of the air venting operation based on the water supply temperature and the heating temperature or the target temperature, and when the determination means determines that the air venting operation is necessary, the control device executes the air venting operation during the hot water supply, and when the determination means determines that the air venting operation is unnecessary, the control device does not execute the air venting operation.

[0009] Further, the control device controls a hot water filling operation for supplying the hot water in the hot water storage tank to the bathtub, and when the determination means determines that the air bleeding operation is necessary, the air bleeding operation is executed when performing the hot water filling operation.

Advantages of the Invention

[0010] According to the present invention, when the determination means determines that air has accumulated in the upper part of the hot water storage tank, the opening degree of the medium-temperature water mixing valve is set to the side where more high-temperature water in the upper part of the hot water storage tank is used to supply hot water and perform the air bleeding operation. When the determination means determines that no air has accumulated in the upper part of the hot water storage tank, by setting the opening degree of the medium-temperature water mixing valve to the side where more medium-temperature water in the middle part of the hot water storage tank is used, the amount of medium-temperature water can be reduced.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0012] Next, a storage type hot water supply device according to an embodiment of the present invention will be described with reference to the drawings. Reference numeral 1 denotes a hot water storage tank unit, which includes a hot water storage tank 2 for storing hot water and cold water inside, a high-temperature side hot water outlet pipe 3 connected to the upper part of the hot water storage tank 2, a medium-temperature side hot water outlet pipe 4 connected to the middle part of the hot water storage tank 2, a medium-temperature water mixing valve 5 for mixing the high-temperature water from the high-temperature side hot water outlet pipe 3 and the medium-temperature water from the medium-temperature side hot water outlet pipe 4, a water supply pipe 6 connected to the lower part of the hot water storage tank 2, a hot water supply mixing valve 8 for mixing the mixed water from the medium-temperature water mixing valve 5 and the low-temperature water from a water supply bypass pipe 7 branched from the water supply pipe 6, a hot water supply temperature sensor 10 provided in a hot water supply pipe 9 connected to the downstream of the hot water supply mixing valve 8, and a hot water supply flow sensor 11 for detecting the hot water supply flow rate.

[0013] Reference numeral 12 denotes a heat pump unit, which includes a heat pump type heating means 18 composed of a compressor 13, a water-cooled refrigerant heat exchanger 14 as a condenser, an electronic expansion valve 15, an outdoor fan 16, and an air heat exchanger 17 as an evaporator for exchanging heat with air, a circulation pump 22 for circulating the hot water in the hot water storage tank 2 through a heating circulation circuit 21 composed of a heating supply pipe 19 and a heating return pipe 20 to the heating means 18, and a heat pump control unit 23 for controlling their driving. Carbon dioxide is used as the refrigerant in the heating means 18 to form a transcritical heat pump cycle. Also, since carbon dioxide is used as the refrigerant, it is possible to boil low-temperature water up to a high temperature of about 90°C without an electric water heater.

[0014] Here, the water-cooled refrigerant heat exchanger 14 employs a counterflow method in which the refrigerant and the hot water in the hot water storage tank 2 as the water to be heated flow counter to each other. In the transcritical heat pump cycle, since the refrigerant is condensed while remaining in the supercritical state during heat exchange, the water to be heated can be efficiently heated to a high temperature. By controlling the expansion valve 15 or the compressor 13 so that the temperature difference between the inlet temperature of the water-cooled refrigerant heat exchanger 14 of the water to be heated and the outlet temperature of the refrigerant becomes constant, it is possible to heat the water to be heated in a state where the COP (energy consumption efficiency) is very good when the inlet temperature of the water-cooled refrigerant heat exchanger 14 of the water to be heated is a relatively low temperature of about 5 to 20°C.

[0015] An inlet temperature sensor 45 for detecting the inlet temperature is provided on the water inlet side of the water-cooled refrigerant heat exchanger 14 of the heating circulation circuit 21, and an outlet temperature sensor 46 as a heating temperature detection means is provided on the outlet side for detecting the heating temperature after heating.

[0016] In addition, a heating bypass valve 24 is provided in the middle of the heating return pipe 20. When preventing freezing, the heating bypass valve 24 is switched to communicate with the heating bypass pipe 25 side, which is a heating bypass path connected to the water supply pipe 6 at the lower part of the hot water storage tank 2, so as to prevent freezing by circulating as a short - circuit through the lower part inside the hot water storage tank 2. This heating bypass valve 24 is arranged at the branch position from the heating return pipe 20 to the heating bypass pipe 25.

[0017] Also, when circulating warm water that is not sufficiently heated at the initial stage of heating by the heating means 18, the hot water is not returned to the upper part of the hot water storage tank 2, but is returned to the lower part of the hot water storage tank 2 through the bypass circulation path via the heating bypass pipe 25. When circulating hot water that has been sufficiently heated thereafter, the heating bypass valve 24 is switched to the upper part side of the hot water storage tank 2.

[0018] 26 is a pressure - reducing valve provided in the water supply pipe 6 for adjusting the water supply pressure.

[0019] 27 is a pressure - relief valve provided in the heating bypass pipe 25 for relieving the pressure in the hot water storage tank 2 and the heating circulation circuit 21.

[0020] This pressure - relief valve 27 opens when the hot water in the hot water storage tank 2 and the heating circulation circuit 21 becomes high - temperature due to the boiling - up operation, the pressure in the storage - type water heater rises, and exceeds a predetermined pressure higher than the water supply pressure. Along with the pressure, the hot water is discharged outside the storage - type water heater.

[0021] 28 is a bath mixing valve for mixing the mixed water from the medium - warm water mixing valve 5 and the low - temperature water from the water supply bypass pipe 7 branched from the water supply pipe 6.

[0022] In addition, 29 is a water - filling valve for communicating the water - filling pipe 30 with the bathtub 31 to supply hot water to the bathtub 31, 32 is a water - filling temperature sensor for detecting the water - filling temperature supplied to the bath, and 33 is a bath flow sensor for detecting the flow rate passing through the water - filling pipe 30. Also, the water - filling path is a path for supplying hot water to the bathtub 31 in the order of the hot water storage tank 2, the medium - warm water mixing valve 5, the bath mixing valve 28, and the water - filling pipe 30.

[0023] 47 is a hot water storage temperature sensor provided outside the hot water storage tank 2, and is provided at predetermined intervals from the upper part to the lower part of the hot water storage tank 2. They are, from top to bottom, the upper hot water storage temperature sensor 47a, the middle hot water storage temperature sensor 47b, the second middle hot water storage temperature sensor 47c, and the lower hot water storage temperature sensor 47d. The middle hot water storage temperature sensor 47b detects the temperature of the medium-temperature water in the hot water storage tank 2.

[0024] 48 is a mixed water temperature sensor that detects the temperature of the mixed water from the medium-temperature water mixing valve 5, and 49 is a water supply temperature sensor that is a water supply temperature detection means for detecting the water supply temperature provided in the water supply pipe 6.

[0025] 34 is a control device composed of a microcomputer or the like, which controls the heat pump control unit 23 to perform temperature control of hot water supply such as boiling-up operation and boiling-up increase operation of the hot water storage tank 2 by the heating circulation circuit 21, and operation control such as filling the bathtub, reheating, and heat preservation.

[0026] Further, the control device 34 is provided with an opening degree control means 35 for controlling the opening degrees of the medium-temperature water mixing valve 5 and the bathtub mixing valve 28. Specifically, the opening degree control means 35 calculates the opening degrees of the medium-temperature water mixing valve 5 and the bathtub mixing valve 28, and drives the valve so as to achieve the calculated opening degrees.

[0027] For example, the opening degree control means 35 can fix the opening degree by instructing the ratio of the opening degree on the high-temperature side to the opening degree on the low-temperature side of the medium-temperature water mixing valve 5 and the bathtub mixing valve 28.

[0028] Further, the opening degree control means 35 can also use the feed-forward opening degree calculated as the control of the opening degree. For example, regarding the bathtub mixing valve 28, the opening degree control means 35 calculates the feed-forward opening degree of the bathtub mixing valve 28 according to the mixed water temperature detected by the mixed water temperature sensor 48, the water supply temperature detected by the water supply temperature sensor 49, and a predetermined filling set temperature, and controls the opening degree of the bathtub mixing valve 28 so as to achieve the calculated feed-forward opening degree.

[0029] Next, regarding the description of the medium-temperature water mixing valve 5, the opening control means 35 calculates the feed-forward opening of the medium-temperature water mixing valve 5 according to the temperatures detected by the upper hot water storage temperature sensor 47a and the intermediate hot water storage temperature sensor 47b provided outside the hot water storage tank 2 and the mixed water set temperature, which is the set temperature of the mixed water mixed by the medium-temperature water mixing valve 5, and controls the opening of the medium-temperature water mixing valve 5 so as to achieve the calculated feed-forward opening.

[0030] Also, the feed-forward opening is calculated according to the temperatures detected by the upper hot water storage temperature sensor 47a and the intermediate hot water storage temperature sensor 47b to obtain the opening of the medium-temperature water mixing valve 5. When the temperature near the medium-temperature side hot water outlet pipe 4 detected by the intermediate hot water storage temperature sensor 47b is higher than the hot water supply set temperature or the water filling set temperature, the medium-temperature water mixing valve 5 is set to 100% opening on the medium-temperature side. When the temperature detected by the intermediate hot water storage temperature sensor 47b is lower than the hot water supply set temperature or the water filling set temperature, the medium-temperature water mixing valve 5 opens the high-temperature side so that the mixed water temperature detected by the mixed water temperature sensor 48 becomes equal to or higher than the hot water supply set temperature or the water filling set temperature. In this way, the medium-temperature water is used more actively than the high-temperature water at the upper part of the hot water storage tank 2 by the feed-forward control of the medium-temperature water mixing valve 5.

[0031] In addition, the opening control means 35 can also use the feedback opening calculated as the control of the opening. For example, regarding the description of the bath mixing valve 28, the feedback opening is calculated so that the actual water filling temperature mixed by the bath mixing valve 28 becomes the water of the preset water filling set temperature, and the feedback opening is controlled so that the temperature detected by the water filling temperature sensor 32 becomes the water of the preset water filling set temperature.

[0032] Further, the control device 34 is provided with a water filling operation control means 36 for controlling the water filling operation described later, a boiling operation control means 37 for controlling the boiling operation described later, and a determination means 38 for determining the necessity of the air bleeding operation described later based on the feed water temperature, the heating temperature or the boiling target temperature.

[0033] Furthermore, the remote controller 39 has a temperature setting switch 40 for setting the hot water supply set temperature, a water filling switch 41 for instructing water filling into the bathtub 31, and a water filling amount setting switch 42 for setting the water filling amount. Furthermore, it is provided with a display unit 43 composed of a dot matrix type fluorescent display tube, and a remote controller control unit 44 composed of a microcomputer that controls the display unit 43 and communicates with the control device 34.

[0034] Next, the boiling operation will be described. When there is a decrease in the stored hot water amount or a boiling requirement during the late-night time zone, the boiling operation control means 37 puts the heating bypass valve 24 in a state of communicating with the lower side of the hot water storage tank 2, and the control device 34 drives the circulation pump 22 located in the middle of the pipe connecting the hot water storage tank 2 and the heating means 18 to pump water up from the lower part inside the hot water storage tank 2, warm it with the heating means 18, and return it to the lower part of the hot water storage tank 2. Then, it is put in a state of communicating with the upper side of the hot water storage tank 2, and by continuing the operation of returning to the upper part of the hot water storage tank 2, the water inside the hot water storage tank 2 is gradually boiled up to high-temperature water.

[0035] Also, the boiling operation control means 37 terminates the boiling operation when the lower hot water storage temperature sensor 47d continuously detects the boiling target temperature after the boiling operation by the heating means 18. Also, in the embodiment, when the lower hot water storage temperature sensor 47d continuously detects the boiling target temperature, the boiling operation is terminated. However, the stored hot water amount may be calculated from the stored hot water temperature detected by the stored hot water temperature sensor 47, and the boiling operation may be terminated when the target stored hot water amount is reached during the boiling operation.

[0036] Also, by performing the boiling operation, the water inside the hot water storage tank 2 becomes high temperature and the pressure inside the hot water storage tank 2 rises. Therefore, during the boiling operation, the hot water is discharged outside the stored hot water type hot water supply device together with the pressure from the pressure relief valve 27, and the pressure inside the hot water storage tank 2 becomes the set pressure of the pressure relief valve 27 (here, 200 kPa). At this time, the air dissolved in the water accumulates in the upper part of the hot water storage tank 2.

[0037] Next, the hot water supply operation will be described. When the hot water tap is opened, water is supplied from the water supply pipe 6 and flows into the lower part of the hot water storage tank 2. At the same time, it passes through the water supply bypass pipe 7 on the side of the hot water mixing valve 8, and the high-temperature water pushed out from the upper part of the hot water storage tank 2 and the medium-temperature water pushed out from the middle part of the hot water storage tank 2 are mixed by the medium-temperature water mixing valve 5. The mixed water mixed by the medium-temperature water mixing valve 5 and the water supply from the water supply bypass pipe 7 on the side of the hot water mixing valve 8 are mixed by the hot water mixing valve 8, and hot water adjusted so that the set hot water temperature is the same as the temperature detected by the hot water temperature sensor 10 is supplied from the hot water tap.

[0038] Next, the hot water filling operation will be described. When the hot water filling switch 41 of the remote control 39 or an automatic operation switch (not shown) is pressed, the hot water filling operation control means 36 opens the hot water filling valve 29, supplies water from the water supply pipe 6, and flows into the lower part of the hot water storage tank 2. At the same time, it passes through the water supply bypass pipe 7 on the side of the bath mixing valve 28, and the high-temperature water pushed out from the upper part of the hot water storage tank 1 and the water supply from the water supply bypass pipe 7 on the side of the bath mixing valve 28 are mixed by the bath mixing valve 28. Hot water adjusted so that the set hot water filling temperature is the same as the temperature detected by the hot water filling temperature sensor 32 flows into the bathtub 31, and the hot water filling starts. Then, the flow rate flowing through the bath flow sensor 33 is detected, and when the total integrated value of the flowing flow rate is divided by the set hot water filling amount, the hot water filling operation control means 36 closes the hot water filling valve 29 to end the hot water filling operation.

[0039] Also, after the boiling operation is completed, when the hot water tap is opened for the hot water supply operation, or when the hot water filling valve 29 is opened during the hot water filling operation, the pressure in the hot water storage tank 2 is released from the pressure that remained at the set pressure of the pressure relief valve 27, and the pressure in the hot water storage tank 2 drops to the set pressure of the pressure reducing valve 26 (here, 170 kPa).

[0040] Next, the operation of the determination means 38 for determining the necessity of the air bleeding operation will be described. Since the water flowing into the hot water storage tank 2 is mainly tap water, generally, oxygen in an amount saturated under atmospheric pressure is dissolved. The determination means 38 estimates whether the dissolved oxygen contained in the water has been released into the hot water storage tank 2 by the water at the feed water temperature detected by the feed water temperature sensor 49 flowing into the hot water storage tank 2 and being boiled up to the heating temperature by the heating means 18 under the set pressure of the pressure reducing valve 26, and determines whether an air venting operation is necessary.

[0041] Also, as the timing for the determination means 38 to determine whether an air venting operation is necessary, it is preferably performed after the completion of the early morning boiling operation, and the necessity of the air venting operation is stored in the control device 34. Note that for the detection of the feed water temperature, it is preferable to use the feed water temperature based on the average value of the feed water temperature of the previous day, and for the heating temperature, it is preferable to use the maximum temperature of the outlet temperature sensor 46 which is the heating temperature detection means during the boiling operation.

[0042] Next, an explanation will be given based on FIG. 2 which is a graph showing the relationship between the water temperature and the saturated dissolved oxygen amount for each pressure, and FIG. 3 which is a table stored in the control device 34 in a more simplified form based on the relationship of FIG. 2. In the microcomputer provided in the control device 34, the table of FIG. 3 is stored in advance, and the feed water temperature and the heating temperature or the boiling target temperature are applied, and it is determined whether an air venting operation is necessary based on whether it is above the determination value.

[0043] For example, when the feed water temperature detected by the feed water temperature sensor 49 is 10°C, the water supplied contains a maximum of 11.29 mg / L of oxygen, and as the feed water temperature rises, the saturated dissolved oxygen amount decreases (line A). Also, line B is the saturated dissolved oxygen amount when under the set pressure of the pressure reducing valve 26 (here, 170 kPa).

[0044] The supplied water (supply water temperature: 10°C, saturated dissolved oxygen content: 11.29 mg / L) is under pressure in the hot water storage tank 2. Even when the temperature of the water is raised by the heating means 18, the air dissolved in the water does not form bubbles until it exceeds line B under the set pressure of the pressure reducing valve 26. However, when it exceeds line B under the set pressure of the pressure reducing valve 26, it forms bubbles and accumulates in the upper part of the hot water storage tank 2. For example, when the supplied water (supply water temperature: 10°C, saturated dissolved oxygen content: 11.29 mg / L) exceeds 37°C, the air dissolved in the water forms bubbles and accumulates in the upper part of the hot water storage tank 2.

[0045] Therefore, when the supply water temperature is 10°C, the determination means 38 determines that an air bleeding operation is necessary based on the stored Figure 3 when the heating temperature or the boiling-up target temperature is 37°C or higher.

[0046] In this way, the determination means 38 determines whether an air bleeding operation is necessary based on whether bubbles are generated from the water supplied into the hot water storage tank 2 based on the supply water temperature and the heating temperature when heated by the heating means 18 under the pressure in the hot water storage tank 2.

[0047] Note that since the pressure in the hot water storage tank 2 also changes according to the set pressure of the pressure reducing valve 26, when the set pressure of the pressure reducing valve 26 is 260 kPa (line C), bubbles will not be generated unless the supplied water (supply water temperature: 10°C, saturated dissolved oxygen content: 11.29 mg / L) is boiled up to 65°C or higher by the heating means 18. Therefore, when the supply water temperature is 10°C, the determination means 38 determines that an air bleeding operation is necessary when the heating temperature or the boiling-up target temperature is 65°C or higher.

[0048] Also, the air bleeding operation will be described. When the determination means 38 determines based on the supply water temperature and the heating temperature that air has accumulated in the upper part of the hot water storage tank 2 and an air bleeding operation is necessary, the control device 34 sets the medium-temperature water mixing valve 5 to 100% on the high-temperature side at the initial stage of starting the hot water filling operation, performs a predetermined amount of hot water filling and discharges it into the bathtub 31, and at the same time performs the hot water filling operation. When it is determined that the air bleeding operation is not necessary, the control device 34 performs the hot water filling operation with the medium-temperature water mixing valve 5 in a feed-forward control manner at an opening degree that actively uses the medium-temperature water during the hot water filling operation.

[0049] Next, the air bleeding operation of the air accumulated in the upper part of the hot water storage tank 2 will be described in detail based on the flowchart of FIG. 3. When the determination means 38 determines that the air bleeding operation is necessary (S1 is Yes), when the hot water filling switch 41 of the remote controller 39 or an automatic operation switch (not shown) is pressed, the control device 34 performs the air bleeding operation, and the hot water filling operation control means 36 starts the hot water filling operation (S2 is Yes).

[0050] When S2 is Yes, the opening degree control means 35 sets the high temperature side connected to the upper part of the hot water storage tank 2 of the medium temperature water mixing valve 5 to 100%, and controls the opening degree of the medium temperature side connected to the middle part of the hot water storage tank 2 at a ratio of 0% (S3), and the opening degree of the bath mixing valve 28 is controlled at the feedback opening degree according to the detected temperature of the hot water filling temperature sensor 32 (S4), and a hot water filling operation of a predetermined amount (here, 10 L) is started (S5). Then, when the hot water filling operation of the predetermined amount (here, 10 L) is completed (S6 is Yes), it proceeds to S7.

[0051] Also, when the determination means 38 determines that the air bleeding operation is not necessary (S1 is No), when the hot water filling switch 41 of the remote controller 39 or an automatic operation switch (not shown) is pressed, the control device 34 performs the air bleeding operation, and the hot water filling operation control means 36 starts the hot water filling operation (S12 is Yes), and proceeds to S7.

[0052] The opening degree control means 35 switches the medium temperature water mixing valve 5 to an opening degree for actively using medium temperature water (here, the feed-forward opening degree) (S7), and sets the opening degree of the bath mixing valve 28 to the feed-forward opening degree (S8).

[0053] The hot water filling operation control means 36 starts a hot water filling operation of 170 L obtained by subtracting the previously filled amount (here, 10 L) so as to reach a predetermined bath setting amount (here, 180 L). When the hot water filling of the predetermined amount has not been performed, a hot water filling operation of the bath setting amount of 180 L is started (S9).

[0054] When the hot water filling operation control means 36 determines that the bathtub 31 has reached the bath set quantity and the bath set temperature (S10 is Yes), it completes the hot water filling operation (S11).

[0055] In this way, when the determination means 38 determines that air has accumulated in the upper part of the hot water storage tank 2, the opening degree of the medium-temperature side of the medium-temperature water mixing valve 5 that does not contribute to the discharge of air is set to 0%, and the opening degree of the high-temperature side of the medium-temperature water mixing valve 5 that enables the discharge of air is set to 100%. In this way, the air in the hot water storage tank 2 can be efficiently discharged into the bathtub 31. When the determination means 38 determines that no air has accumulated in the upper part of the hot water storage tank 2, the amount of medium-temperature water can be reduced by actively using the medium-temperature water by adjusting the opening degree of the medium-temperature water mixing valve 5.

[0056] Also, at the initial stage of the hot water filling operation, only the air accumulated in the upper part of the hot water storage tank 2 is sent out from the medium-temperature water mixing valve 5, and the temperature detected by the hot water filling temperature sensor 32 becomes the temperature of the water supply from the water supply bypass pipe 7. Therefore, by controlling the opening degree of the bath mixing valve 28 with the feedback opening degree, since the hot water filling temperature detected by the hot water filling temperature sensor 32 is less than the bath set temperature, the opening degree of the medium-temperature water mixing side of the bath mixing valve 28 opens wide, and the air accumulated in the upper part of the hot water storage tank 2 can be easily discharged from the medium-temperature water mixing valve 5.

[0057] Also, since the air accumulated in the upper part of the hot water storage tank 2 can be discharged into the bathtub 31 during the initial predetermined amount of the hot water filling operation, the air can be safely discharged into the bathtub 31 at the initial stage of the hot water filling operation when there is still no one in the bathtub 31, and the air accumulated in the upper part of the hot water storage tank 2 can be completely discharged at the initial stage of the hot water filling operation.

[0058] Also, by setting the opening degree of the medium-temperature water mixing valve 5 to 100% on the high-temperature side and setting the bath mixing valve 28 to the feedback opening degree, the air accumulated in the upper part of the hot water storage tank 2 can be quickly removed.

[0059] Note that the present invention is not limited to the embodiments, and modifications are not precluded as long as the gist is not changed. For example, in the embodiments, the feed water temperature detection means has been described as the feed water temperature sensor 49, but the lower hot water storage temperature sensor 47d or the incoming water temperature sensor 45 may be used to detect the feed water temperature. Similarly, although the heating temperature detection means has been described as the outlet temperature sensor 46, the upper hot water storage temperature sensor 47a flowing out into the hot water storage tank 2 may also be used, or the target temperature of the boiling-up operation instructed by the control device 34 may be used instead of the heating temperature.

[0060] Also, in the embodiments, the heat pump type heating means 18 has been described, but an electric heater or a combustion type heating means 18 may also be used. As long as the determination means 38 can estimate the generation of bubbles based on the feed water temperature and the heating temperature when heated by the heating means 18 and determine the necessity of the air venting operation, it is acceptable.

[0061] Also, when the hot water supply faucet is opened with air accumulated in the upper part of the hot water storage tank 2, hot water is supplied together with the air. Therefore, from the viewpoint of being discharged in an unexpected direction, the air venting operation is performed during the hot water filling operation. However, it may be selected to perform the air venting operation during the hot water supply operation depending on the user's choice.

[0062] Also, although the graphs in FIG. 2 and the tables in FIG. 3 have been described based on the saturated dissolved oxygen amount that can be dissolved, graphs and tables may be created based on the average dissolved amount assuming that nitrogen, carbon dioxide, etc. other than oxygen are also dissolved in water, and the graphs and tables may be stored in the microcomputer of the control device 34 based on the average dissolved amount, and the necessity of the air venting operation may be determined based on the feed water temperature and the heating temperature.

Explanation of Reference Numerals

[0063] 2 Hot water storage tank 6 Feed water pipe 8 Hot water supply mixing valve 18 Heating means 26 Pressure reducing valve 28 Bath mixing valve 29 Hot water filling valve 30 Hot water filling pipe 31 Bathtub 34 Control device 35 Opening control means 36 Overflow operation control means 38 Judgment means 45 Inlet water temperature sensor (feed water temperature detection means) 46 Outlet temperature sensor (heating temperature detection means) 47 Hot water storage temperature sensor 47a Upper hot water storage temperature sensor (heating temperature detection means) 47d Lower hot water storage temperature sensor (feed water temperature detection means) 49 Feed water temperature sensor (feed water temperature detection means)

Claims

1. A hot water storage tank for storing hot water, heating means for boiling the hot water in the hot water storage tank to a target temperature, a medium-temperature hot water mixing valve for mixing the high-temperature water taken out from the upper part of the hot water storage tank and the medium-temperature hot water taken out from the middle part of the hot water storage tank, a water supply pipe connected to the lower part of the hot water storage tank for supplying water to the hot water storage tank, water supply temperature detection means for detecting the water supply temperature, heating temperature detection means for detecting the heating temperature of the water boiled up by the heating means, a pressure reducing valve provided in the middle of the water supply pipe for adjusting the water supply pressure, In a hot water storage type water supply device comprising a control device for controlling an air bleeding operation of opening the high-temperature water side opening degree of the medium-temperature hot water mixing valve wide to send out the air accumulated in the hot water storage tank to the outside of the hot water storage tank together with the hot water supply during the hot water supply operation, the control device is provided with determination means for determining the necessity of the air bleeding operation based on the water supply temperature and the heating temperature or the target temperature, the control device, when the determination means determines that the air bleeding operation is necessary, the air bleeding operation is executed during the hot water supply, when the determination means determines that the air bleeding operation is unnecessary, the air bleeding operation is not executed. The hot water storage type water supply device is characterized by this.

2. the control device controls a hot water filling operation of supplying the hot water in the hot water storage tank to a bathtub, when the determination means determines that the air bleeding operation is necessary, the air bleeding operation is executed when the hot water filling operation is performed. The hot water storage type water supply device according to Claim 1 is characterized by this.

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