Hot water storage type water heater

Abstract

To provide a hot water storage type water heater capable of suppressing hot water shortage and useless boiling-up.SOLUTION: A hot water storage type water heater includes: a hot water storage tank unit incorporating a hot water storage tank; heating means for heating water in the hot water storage tank; time zone dividing means for dividing one day into a plurality of time zones; hot water supply level setting means for making a hot water supply amount estimated in every time zone divided by the time zone dividing means correspond to the divided time zone, and setting as a hot water supply level in the time zone; a control section for operating the heating means and controlling boiling-up operation of storing hot water in the hot water storage tank; and boiling-up termination condition setting means for setting a condition of the boiling-up operation so as to complete the boiling-up operation corresponding to the hot water supply level set by the hot water supply level setting means until the start of the time zone. The control section executes the boiling-up operation according to the condition set by the boiling-up termination condition setting means.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a storage type water heater. [Background technology]

[0002] Conventionally, storage-type water heaters operate to boil hot water during the late night hours when electricity rates are cheaper in order to ensure the amount of hot water expected for the next day's daytime supply, and during the daytime hours they operate to prevent running out of hot water.

[0003] Patent Document 1 discloses a technique for controlling boiling during daytime and late-night hours. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-76341 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventional storage-type water heaters are designed to provide hot water during the daytime but not during the night, but this creates the problem of running out of hot water or unnecessary boiling when hot water is provided during the night but not during the daytime.

[0006] The present disclosure has been made to solve the above-mentioned problems. An object of the present disclosure is to provide a storage type hot water heater that can prevent hot water shortages and unnecessary boiling. [Means for solving the problem]

[0007] The hot water storage type water heater of the present disclosure comprises a hot water storage tank unit incorporating a hot water storage tank, a heating means for heating water in the hot water storage tank, a time zone division means for dividing a day into a plurality of time zones, a hot water supply level setting means for matching the amount of hot water supply predicted for each time zone divided by the time zone division means to the divided time zone and setting the hot water supply level for that time zone, a control unit for operating the heating means to control the boiling operation of storing hot water in the hot water storage tank, and a boiling end condition setting means for setting the conditions for the boiling operation so that the boiling operation corresponding to the hot water supply level set by the hot water supply level setting means is completed by the start of the time zone, and the control unit carries out the boiling operation in accordance with the conditions set by the boiling end condition setting means. In addition, the hot water storage type water heater of the present disclosure comprises a hot water storage tank unit incorporating a hot water storage tank, a heating means for heating water in the hot water storage tank, a hot water supply level setting means for setting the hot water supply amount predicted for each time period of the day as the hot water supply level for that time period, a time zone division means for dividing a day into multiple time zones based on the differences in the hot water supply levels set by the hot water supply level setting means, a control unit for operating the heating means to control the boiling operation to store hot water in the hot water storage tank, and a boiling end condition setting means for setting the conditions for the boiling operation so that the boiling operation corresponding to the hot water supply level set by the hot water supply level setting means is completed by the start of the time period divided by the time zone division means, and the control unit carries out the boiling operation in accordance with the conditions set by the boiling end condition setting means. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to obtain a storage type water heater that can perform boiling operation depending on the usage situation of the storage type water heater. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram showing a storage type hot water heater according to a first embodiment. [Figure 2] 4 is a flowchart showing a control operation of the first embodiment. [Figure 3] 10 is a flowchart showing a control operation of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments will be described with reference to the drawings. Common or corresponding elements in each drawing are designated by the same reference numerals, and descriptions thereof will be simplified or omitted. In the following description, terms such as "water," "hot water," "warm water," and "hot water" generally refer to liquid water, and may include anything from cold water to boiling water. Furthermore, the configurations shown in the following embodiments are examples of the technical ideas of the present disclosure, and may be combined with other known technologies, or multiple technical ideas described in the present disclosure may be combined. Furthermore, parts of the configurations may be omitted or modified without departing from the spirit of the present disclosure.

[0011] Embodiment 1 FIG. 1 is a diagram showing a storage-type hot water heater according to a first embodiment. In this embodiment, the calorific value of hot water is calculated, for example, as the difference from the calorific value of water at a temperature supplied from a water source. In addition, in this embodiment, when describing the calorific value of hot water, the calorific value is described in units of the amount of hot water [L] when converted into the calorific value of hot water at a predetermined reference hot water temperature. The value of the reference hot water temperature may be, for example, 40°C.

[0012] As shown in FIG. 1, the hot water storage tank unit 40 has a built-in hot water storage tank 1. The hot water storage tank 1 is connected to a heat pump unit 2, which is a heating means for heating the water in the hot water storage tank 1, by a heating circulation circuit 3. The heat pump unit 2 includes a heat pump circuit in which a compressor, a hot water supply heat exchanger, an expansion valve, and an air heat exchanger are connected in sequence by refrigerant piping. The heating circulation circuit 3 connects the top and bottom of the hot water storage tank 1 to the heat pump unit 2. An HP circulation pump 4 is provided in the piping section connecting the bottom of the hot water storage tank 1 to the heat pump unit 2. The HP circulation pump 4 guides water taken from the bottom of the hot water storage tank 1 into the heat pump unit 2, where it is boiled to high temperature water and returned to the top of the hot water storage tank 1.

[0013] First to sixth temperature sensors 5a to 5f are provided around the outer periphery of the hot water storage tank 1 at positions corresponding to the hot water storage tank's volume of 50 L, 100 L, 150 L, 170 L, 220 L, and 270 L from the top of the hot water storage tank 1. A seventh temperature sensor 5g is provided on the side of the heating circulation circuit 3 that connects to the bottom of the hot water storage tank 1. The first to seventh temperature sensors 5a to 5g function as residual hot water heat quantity detection means that detect the residual hot water heat quantity in the hot water storage tank 1, and detect the temperature of the hot water at those positions. The hot water storage tank temperature sensor 6 is provided at the top of the hot water storage tank 1, and detects the temperature of the hot water that is heated by the heat pump unit 2 and returned to the top of the hot water storage tank 1.

[0014] The hot water storage tank unit 40 further includes an HP circulation pump 4, a general hot water supply side electric mixing valve 7, high temperature piping 8, a water supply pipe 9, a bath hot water supply side electric mixing valve 11, a bath opening / closing valve 13, a bath circulation pump 14, a water inlet switching valve 17, a hot water supply flow rate sensor 19, a hot water supply temperature sensor 20, a bath flow rate sensor 21, a bath temperature sensor 22, a water supply temperature sensor 23, a hot water outlet switching valve 26, a medium temperature return switching valve 27, a medium temperature extraction switching valve 28, and a medium temperature piping 30.

[0015] The upstream side of water supply pipe 9 is connected to a water source such as a water pipe. The downstream side of water supply pipe 9 branches into water supply pipe 9a and water supply pipe 9b. Water supply pipe 9a is connected to the bottom of hot water storage tank 1. Low-temperature water supplied from the water source flows from water supply pipe 9a into the bottom of hot water storage tank 1, thereby keeping the hot water storage tank 1 full of water.

[0016] The medium-temperature extraction switching valve 28 has a medium-temperature inlet 28a, a low-temperature inlet 28b, and a water outlet 28c. A water supply pipe 9b is connected to the low-temperature inlet 28b. One end of a medium-temperature piping 30 is connected to the medium-temperature inlet 28a. The upstream portion of the high-temperature piping 8 communicates with the inside of the hot water storage tank 1 at a first position 1a located at the top of the hot water storage tank 1. The other end of the medium-temperature piping 30 communicates with the inside of the hot water storage tank 1 at a second position 1b located lower than the first position 1a. The second position 1b is located higher than the lower part of the hot water storage tank 1 to which the water supply pipe 9a is connected. In other words, the second position 1b is located midway between the top and bottom of the hot water storage tank 1.

[0017] Medium-temperature water supplied from the hot water storage tank 1 through the medium-temperature piping 30 flows into the medium-temperature inlet 28a. Low-temperature water that is at a lower temperature than the medium-temperature water flows into the low-temperature inlet 28b. In this embodiment, low-temperature water supplied from the water source through the water supply pipe 9b flows into the low-temperature inlet 28b. The medium-temperature extraction switching valve 28 can switch its flow path between a "medium-temperature position" and a "low-temperature position." In the "medium-temperature position," the medium-temperature inlet 28a is connected to the water outlet 28c, and the low-temperature inlet 28b is blocked. In the "medium-temperature position," the medium-temperature water from the medium-temperature piping 30 flows into the water outlet 28c. In the "low-temperature position," the low-temperature inlet 28b is connected to the water outlet 28c, and the medium-temperature inlet 28a is blocked. In the "low-temperature position," the low-temperature water from the water supply pipe 9b flows into the water outlet 28c.

[0018] The general hot water supply side electric mixing valve 7 has a hot water side inlet 7a, a cold water side inlet 7b, and a hot water outlet 7c. The bath hot water supply side electric mixing valve 11 has a hot water side inlet 11a, a cold water side inlet 11b, and a hot water outlet 11c. The downstream portion of the high-temperature piping 8 is connected to each of the hot water side inlet 7a and the hot water side inlet 11a. The water outlet 28c of the medium-temperature extraction switching valve 28 is connected to each of the cold water side inlet 7b and the cold water side inlet 11b.

[0019] One end of the first hot water supply pipe 10 is connected to the hot water outlet 7c. The general hot water supply side electric mixing valve 7 mixes high-temperature hot water supplied from the hot water storage tank 1 through the high-temperature piping 8 with water from the water outlet 28c of the medium-temperature extraction switching valve 28, and adjusts the temperature. The temperature-adjusted hot water flows into the first hot water supply pipe 10. The hot water passing through the first hot water supply pipe 10 is supplied to, for example, a faucet, a shower, etc.

[0020] One end of the second hot water supply pipe 18 is connected to the hot water outlet 11c. The bath hot water supply side electric mixing valve 11 mixes high-temperature hot water supplied from the hot water storage tank 1 through the high-temperature piping 8 with water from the water outlet 28c of the medium-temperature extraction switching valve 28, and adjusts the temperature. The temperature-adjusted hot water flows into the second hot water supply pipe 18.

[0021] A water supply temperature sensor 23 is provided in the water supply pipe 9. The water supply temperature sensor 23 detects the water supply temperature, which is the temperature of the water flowing through the water supply pipe 9. A hot water supply flow rate sensor 19 and a hot water supply temperature sensor 20 are provided in the first hot water supply pipe 10. The hot water supply flow rate sensor 19 detects the flow rate of hot water flowing through the first hot water supply pipe 10. The hot water supply temperature sensor 20 detects the first hot water temperature, which is the temperature of the hot water flowing through the first hot water supply pipe 10. A bath opening / closing valve 13, a bath flow rate sensor 21, and a bath temperature sensor 22 are provided in the second hot water supply pipe 18. The bath flow rate sensor 21 detects the flow rate of hot water flowing through the second hot water supply pipe 18. The bath temperature sensor 22 detects the second hot water temperature, which is the temperature of the hot water flowing through the second hot water supply pipe 18.

[0022] The second hot water supply pipe 18 is connected to the bath-side circulation circuit 12. A heat exchanger 15 is arranged inside the hot water storage tank unit 40. The bath-side circulation circuit 12 is connected to a bathtub (not shown) in the bathroom outside the hot water storage tank unit. In the following explanation, the hot water stored in the bathtub may be referred to as "bath water." The bath-side circulation circuit 12 is a path that can draw bath water from the bathtub and return it to the bathtub after passing through the heat exchanger 15. When the bath circulation pump 14 connected midway along the bath-side circulation circuit 12 is operated, the bath water from the bathtub passes through the bath-side circulation circuit 12 and circulates back to the bathtub.

[0023] The second hot water supply pipe 18 forms a passage for hot water supplied to the bathtub from the hot water outlet 11c of the bath hot water supply side electric mixing valve 11. The bath on / off valve 13 opens and closes the passage of the second hot water supply pipe 18. Except when hot water is being supplied to the bathtub, the bath on / off valve 13 is closed and hot water does not flow to the second hot water supply pipe 18. When hot water is being poured into the bathtub from the hot water storage tank unit 40, the following occurs: The bath on / off valve 13 is opened and hot water flows into the second hot water supply pipe 18. The bath hot water supply side electric mixing valve 11 is controlled so that the temperature of the hot water flowing through the second hot water supply pipe 18 is equal to the target temperature. The hot water that passes through the second hot water supply pipe 18 flows into the bathtub through the bath side circulation circuit 12. Closing the bath on / off valve 13 stops the pouring of hot water into the bathtub. In the following explanation, the action of filling the bathtub with hot water as described above is referred to as "filling the bathtub."

[0024] The water inlet switching valve 17 is a flow path switching means having inlet ports a and b and outlet port c. The water inlet switching valve 17 is configured to be able to switch the flow path between two paths, ac and bc.

[0025] The hot water outlet switching valve 26 is a flow path switching means having inlet ports a and b and outlet ports c and d. The hot water outlet switching valve 26 is configured to be able to switch the flow path among four paths: ac, ad, bc, and bd.

[0026] The medium-temperature return switching valve 27 is a flow path switching means having an inlet port a and outlet ports b, c, and d. The medium-temperature return switching valve 27 is configured to be able to switch the flow path among three paths ab, ac, and ad.

[0027] The hot water storage tank unit 40 has a low-temperature pipe 41, a first water supply pipe 42, a first hot water pipe 43, a bath heat recovery pipe 32, a third hot water pipe 45, a fourth hot water pipe 46, and a medium-temperature return pipe 29. The low-temperature pipe 41 connects the bottom of the hot water storage tank 1 to the a port of the water inlet switching valve 17. The first water supply pipe 42 connects the c port of the water inlet switching valve 17 to the inlet of the HP circulation pump 4. The HP supply pipe 48 connects the outlet of the HP circulation pump 4 to the inlet of the heat pump unit 2. The HP return pipe 49 connects the outlet of the heat pump unit 2 to the b port of the hot water outlet switching valve 26. The first hot water pipe 43 connects the d port of the hot water outlet switching valve 26 to the a port of the medium-temperature return switching valve 27. The bath heat recovery pipe 32 connects the c port of the hot water outlet switching valve 26 to the bottom of the hot water storage tank 1. The third hot water pipe 45 connects the b port of the medium temperature return switching valve 27 and the hot water inlet outlet 1c at the top of the hot water storage tank 1. The fourth hot water pipe 46 connects the d port of the medium temperature return switching valve 27 and a position midway along the high temperature pipe 8. The medium temperature return pipe 29 connects the c port of the medium temperature return switching valve 27 and the hot water inlet 1d provided between the top and middle of the hot water storage tank 1.

[0028] The first tank circulation piping 16 connects between a midpoint on the third hot water piping 45 and the tank water inlet of the heat exchanger 15. The second tank circulation piping 50 connects between the tank water outlet of the heat exchanger 15 and port b of the water inlet switching valve 17. The second water supply piping 51 branches off from the HP supply piping 48 between the HP circulation pump 4 and the inlet of the heat pump unit 2, and is connected to port a of the hot water outlet switching valve 26. The bath heat recovery piping 31 branches off from a midpoint on the second tank circulation piping 50 and is connected to a midpoint on the medium temperature piping 30.

[0029] The storage type water heater of this embodiment is equipped with a control unit 24 as a control means. The control unit 24 is electrically connected to each of the actuators and sensors described above. The control unit 24 controls the boiling operation of the storage type water heater. The boiling operation is an operation in which the heat pump unit 2 is operated to store hot water in the hot water storage tank 1.

[0030] The control unit 24 and the remote control 25 can communicate bidirectionally via wired or wireless communication. The control unit 24 and the remote control 25 may also be able to communicate via a network. The remote control 25 is an example of a user interface. The remote control 25 has an operation unit operated by the user and a display unit 25a that displays information. The remote control 25 may also have a touch screen that functions as both the operation unit and the display unit 25a. By operating the remote control 25, the user can remotely control the hot water storage type water heater and perform various settings. The display unit 25a of the remote control 25 functions as a notification means that notifies the user of information. The remote control 25 in this embodiment has the display unit 25a as a notification means, but as a variant, it may also have other notification means, such as a voice guidance device.

[0031] In this embodiment, the remote control 25 may be installed on a wall in the kitchen, living room, bathroom, etc. Alternatively, a mobile information terminal such as a smartphone may be configured to have a function as a user interface like the remote control 25. A plurality of remote controls 25 may be capable of communicating with the control unit 24.

[0032] The control unit 24 is electrically connected to each of the heat pump unit 2, HP circulation pump 4, first to seventh temperature sensors 5a to 5g, hot water storage tank temperature sensor 6, general hot water supply side electric mixing valve 7, bath hot water supply side electric mixing valve 11, bath opening / closing valve 13, bath circulation pump 14, water inlet switching valve 17, hot water supply flow sensor 19, hot water supply temperature sensor 20, bath flow sensor 21, bath temperature sensor 22, water supply temperature sensor 23, and remote control 25, and controls the operation of each.

[0033] The control unit 24 is equipped with a heat requirement prediction unit 24a. Based on the user's past hot water load data, the heat requirement prediction unit 24a predicts the amount of heat storage required to avoid a hot water shortage for the hot water load. The calculation method involves storing the hot water load data for each specified time period on a daily basis based on information from the timer, the hot water temperature sensor 20, the hot water flow rate sensor 19, the bath temperature sensor 22 (which measures the bath temperature), and the bath flow rate sensor 21. The heat requirement prediction unit 24a predicts the amount of heat required to avoid a hot water shortage for the stored hot water load, taking into account simultaneous boiling operation at a specified boiling capacity. The heat requirement can be calculated by subtracting the amount of heat that can be generated during a specified time interval from the total load during that time interval. The most reliable heat requirement can be determined by calculating the heat requirement for all possible start and end times for a specified time interval and then determining the maximum value.

[0034] The control unit 24 determines that the hot water is out of water when the amount of hot water stored in the hot water storage tank 1 is insufficient to supply hot water to the faucet or bathtub. For example, when the temperature measured by the first temperature sensor 5a installed on the top level of the hot water storage tank 1 drops below a predetermined temperature, the control unit 24 generates an out-of-hot water error.

[0035] The control unit 24 further includes a time zone division means 24b, a hot water supply level setting means 24c, and a boiling end condition setting means 24d. The time zone division means 24b divides a day into a plurality of time zones. The hot water supply level setting means 24c corresponds the amount of hot water predicted for each time zone divided by the time zone division means 24b to the divided time zone and sets the hot water supply level for that time zone. The boiling end condition setting means 24d sets end conditions for the boiling operation so that the boiling operation corresponding to the hot water supply level set by the hot water supply level setting means 24c is completed by the start of the relevant time zone. In other words, the boiling end condition setting means 24d sets end conditions for the boiling operation so that the amount of hot water stored in the hot water storage tank 1 corresponding to the hot water supply level set by the hot water supply level setting means 24c is secured by the start of the relevant time zone. The control unit 24 performs the boiling operation in accordance with the conditions set by the boiling end condition setting means 24d.

[0036] The hot water supply level is a broad classification into several stages according to the predicted amount of hot water supply. For example, Hot water level 1: Estimated hot water supply volume is 0L to 100L Hot water level 2: Estimated hot water supply volume is 100L to 200L Hot water level 3: Estimated hot water supply volume is 200L to 300L It may also be possible to use the following. In the above example, the amounts are classified in 100L intervals, but the amounts of hot water supplied may also be classified in smaller intervals.

[0037] The conditions for ending the boiling operation include information about the scheduled time to end the boiling operation and information about the amount of hot water stored at the time of ending the boiling operation. The control unit 24 starts the boiling operation in advance so that the amount of hot water stored in the hot water storage tank 1 can be secured by the scheduled time.

[0038] 2 is a flowchart showing the control operation of the first embodiment. The following description will be made with reference to FIG.

[0039] In step S100 of Fig. 2, a day is divided into multiple time slots based on past hot water usage, etc., and it is determined whether the hot water supply level, which is the amount of hot water to be supplied for each time slot, has been automatically set by the time slot division means 24b and the hot water supply level setting means 24c of the control unit 24. If the level has been automatically set, the process proceeds to step S101, and the hot water supply level control from step S130 onwards is performed using the setting. If the level has not been automatically set, the setting is performed in the procedure of steps S110 to S122, and the hot water supply control from step S130 onwards is then performed. This makes it possible to perform the hot water supply control from step S130 onwards even when there is no information on past hot water usage, etc., and automatic setting is not possible.

[0040] In step S110, a method for dividing a day into multiple time periods is determined. In step S111, the user divides a day into multiple time periods with variable times using the remote control 25 or the like. This allows the user to set any time period that suits their actual usage, improving convenience. In step S112, a day is divided into multiple time periods with predetermined fixed times. This makes it possible to divide a day into multiple time periods even if the user is unable to set the time period division or has forgotten to set it.

[0041] In step S120, a method for setting the hot water supply level, which is the amount of hot water predicted for each divided time period, is determined. If the user has set the hot water supply level, the process proceeds to step S121. In step S121, the hot water supply level setting means 24c allows the user to set the hot water supply level for each time period via remote control 25 or the like. In this way, the hot water supply level setting means 24c may be configured so that the user can change the hot water supply level for each time period. This allows the user to set the hot water supply level as desired according to their actual usage, improving convenience.

[0042] The hot water supply level setting means 24c may be configured to allow the user to select the hot water supply level for each time period from a plurality of preset fixed values, thereby enabling the user to easily set the hot water supply level.

[0043] If the user has not set the hot water supply level in step S120, the process proceeds to step S122. In step S122, the hot water supply level setting means 24c sets a predetermined hot water supply level for each time period. This allows operation even when the user is unable to set the level or has forgotten to set it. In this way, the hot water supply level setting means 24c corresponds the amount of hot water to be supplied for each time period divided by the time period dividing means 24b to the divided time period, and sets the hot water supply level for that time period.

[0044] In step S130, a selection is made between using the hot water level boiling control of this embodiment, which is the boiling control, or using conventional boiling control using late-night power. If the remote control 25 or other device is set to use the hot water level boiling control, the process proceeds to step S140. If the remote control 25 or other device is set to use the conventional boiling control using late-night power, the process proceeds to step S131. In step S131, conventional boiling control using late-night power is implemented. This allows for easy switching to conventional boiling control using late-night power when hot water usage conditions change significantly, for example, when concentrated hot water usage shifts from mainly late-night to mainly daytime, thereby eliminating the need to replace the hot water storage type water heater. The processing in step S130 corresponds to a switching means that can switch between a "day / night-independent boiling operation mode" and a "nighttime power boiling operation mode" that performs boiling operation during late-night hours depending on the hot water supply level during daytime hours.

[0045] In steps S140 to S143, the boiling end conditions are set based on the day of the week information and hot water supply level for the next time period. In step S140, the boiling end condition setting means 24d determines what day of the week and hot water supply level for the next time period are. If it is Monday and hot water supply level 1, the boiling end condition setting means 24d sets the boiling end conditions corresponding to Monday and hot water supply level 1 (step S141). If it is Monday and hot water supply level 2, the boiling end conditions corresponding to Monday and hot water supply level 2 are set (step S142). If it is Monday and hot water supply level 3, the boiling end conditions corresponding to Monday and hot water supply level 3 are set (step S143). The same applies to Tuesdays and onwards.

[0046] As described above, the control unit 24 has a calendar function for identifying the day of the week. The boiling end condition setting means 24d recognizes the hot water supply level for each time period, divided by day of the week. The control unit 24 performs boiling operation according to the conditions set according to the hot water supply level divided by day of the week. This makes it possible to suppress unnecessary boiling operation, for example, when a hot water storage type water heater is used for business purposes, even when the operating conditions are different from normal conditions, such as on a closed day.

[0047] In step S150, it is determined whether or not to operate the heat pump unit 2, which is the heating means. If the boiling end condition for the current time period is met, the heating means is not operated (step S151). If the condition is not met, the heating means is operated (step S152). This makes it possible to prevent unnecessary boiling operation in which the heating means is operated even though the boiling end condition is met.

[0048] As explained above, in this embodiment, a day is divided into multiple time periods, and the end condition for the boiling operation is set based on the hot water supply level, which is the amount of hot water predicted for the next time period, so it is possible to perform boiling operation according to the usage status of the hot water storage type water heater regardless of whether it is daytime or late at night. Therefore, it is possible to prevent hot water shortages and unnecessary boiling.

[0049] Embodiment 2 Next, a second embodiment will be described with reference to Fig. 3. The differences from the first embodiment will be mainly described, and the description of the commonalities will be simplified or omitted. Elements that are common to or correspond to the elements described above will be given the same reference numerals. Fig. 3 is a flowchart showing the control operation of the second embodiment.

[0050] In the second embodiment, the hot water supply level setting means 24c sets the amount of hot water supply predicted for each time period of the day as the hot water supply level for that time period. The time period division means 24b divides a day into multiple time periods based on the differences in the hot water supply levels set by the hot water supply level setting means 24c. The boiling end condition setting means 24d sets the end conditions for the boiling operation so that the boiling operation corresponding to the hot water supply level set by the hot water supply level setting means 24c is completed by the start of the time period divided by the time period division means 24b. In other words, the boiling end condition setting means 24d sets the end conditions for the boiling operation so that the amount of hot water stored in the hot water storage tank 1 corresponding to the hot water supply level set by the hot water supply level setting means 24c is secured by the start of the time period.

[0051] In step S200 of Fig. 3, it is determined whether time periods for each hot water supply level have been automatically set by the time period dividing means 24b and the hot water supply level setting means 24c of the control unit 24 based on past hot water usage, etc. If they have been automatically set, the boiling control from step S130 onwards is performed using those settings, and if they have not been set, the boiling control from step S130 onwards is performed after setting them in the procedure of steps S210 to S221. This makes it possible to perform boiling control from step S130 onwards even when there is no information on past hot water usage, etc., and automatic setting is not possible.

[0052] In step S210, a method for setting a time zone for each hot water supply level is determined. That is, in step S210, it is determined whether the user sets a time zone for each hot water supply level. If the user sets a time zone for each hot water supply level, the process proceeds to step S211. In step S211, the hot water supply level setting means 24c prompts the user to set a time zone for each hot water supply level via the remote control 25 or the like. This allows the user to set any time zone according to their actual usage, improving convenience. On the other hand, if the user does not set a time zone for each hot water supply level, the process proceeds to step S212. In step S212, the hot water supply level setting means 24c sets a predetermined time zone for each hot water supply level. This allows operation even if the user is unable to set or forgets to set it. As described above, in step S211 or step S212, the hot water supply level setting means 24c sets the hot water supply amount predicted for each time zone of the day as the hot water supply level for that time zone. In step S211, the hot water supply level setting means 24c may be configured to allow the user to change the hot water supply level for each time period, thereby enabling any setting according to the actual usage situation of the user, thereby improving convenience.

[0053] The process proceeds from step S211 or step S212 to step S221. In step S221, time zone dividing means 24b divides one day into multiple time zones based on the differences in the hot water supply levels set by hot water supply level setting means 24c. For example, if hot water supply level 1 is set to midnight to 6:00, hot water supply level 2 is set to 6:00 to 9:00, hot water supply level 3 is set to 9:00 to 17:30, and hot water supply level 2 is set to 17:30 to midnight, one day is divided into four time zones: midnight to 6:00, 6:00 to 9:00, 9:00 to 17:30, and 17:30 to midnight. This eliminates the need to divide time zones when the hot water supply level crosses over specified time zones, simplifies control operations, and allows consistent boiling operation, improving convenience and efficiency.

[0054] After step S211, the process proceeds to step S130. The processes from step S130 onwards are the same as those in the first embodiment, and therefore the explanation will be omitted.

[0055] As explained above, in this embodiment, the day is divided into multiple time periods based on the hot water supply level, which is the amount of hot water predicted for each time period, and the conditions for ending the hot water supply operation are set, so it is possible to perform hot water supply operation that suits the usage situation of the hot water storage type water heater regardless of whether it is daytime or late at night. Therefore, it is possible to prevent hot water shortages and unnecessary boiling.

[0056] The hot water storage type water heater of the present disclosure has been described above using embodiments, but as mentioned above, the present disclosure is not limited to the above embodiments. For example, with regard to hot water supply levels, although the first and second embodiments have been described mainly on the case where there are three or more hot water supply levels, it is also possible to configure the hot water supply with two levels, for example, hot water supply level 0 for non-business hours and hot water supply level 1 for business hours.

[0057] Various aspects of the present disclosure are summarized below as appendices.

[0058] (Appendix 1) a hot water storage tank unit with a built-in hot water storage tank; a heating means for heating the water in the hot water storage tank; a time zone dividing means for dividing a day into a plurality of time zones; a hot water supply level setting means for setting the hot water supply amount predicted for each of the time periods divided by the time period dividing means as the hot water supply level for the time period; a control unit that operates the heating means to control a boiling operation for storing hot water in the hot water storage tank; A boiling end condition setting means for setting conditions for the boiling operation so that the boiling operation corresponding to the hot water supply level set by the hot water supply level setting means is completed by the start of the time period; Equipped with The control unit performs the boiling operation in accordance with the conditions set by the boiling end condition setting means. (Appendix 2) a hot water storage tank unit with a built-in hot water storage tank; a heating means for heating the water in the hot water storage tank; a hot water supply level setting means for setting the hot water supply amount predicted for each time period of the day as the hot water supply level for that time period; a time zone dividing means for dividing one day into a plurality of time zones according to the difference in the hot water supply level set by the hot water supply level setting means; a control unit that operates the heating means to control a boiling operation for storing hot water in the hot water storage tank; A boiling end condition setting means for setting conditions for the boiling operation so that the boiling operation corresponding to the hot water supply level set by the hot water supply level setting means is completed by the start of the time period divided by the time period dividing means; Equipped with The control unit performs the boiling operation in accordance with the conditions set by the boiling end condition setting means. (Appendix 3) 2. The hot water storage type water heater according to claim 1, wherein the time zone dividing means is capable of dividing a day into fixed time periods. (Appendix 4) 2. The hot water storage type water heater according to claim 1, wherein the time zone dividing means is capable of dividing a day into variable time periods set by a user. (Appendix 5) A hot water storage type water heater according to any one of appendices 1 to 4, wherein the hot water supply level setting means allows the hot water supply level for each time period to be selected from a plurality of preset fixed values. (Appendix 6) 6. The hot water storage type water heater according to any one of appendices 1 to 5, wherein the hot water supply level setting means allows a user to change the hot water supply level for each time period. (Appendix 7) A hot water storage type water heater as described in any one of Appendix 1 to Appendix 6, equipped with a switching means that can switch between a ``boiling operation mode regardless of day or night'' that uses the boiling operation conditions set by the boiling end condition setting means, and a ``boiling operation mode using late-night power'' that performs the boiling operation during late-night hours depending on the hot water supply level during daytime hours. (Appendix 8) Equipped with a calendar function that keeps track of the days of the week, The boiling end condition setting means recognizes the hot water supply level for each time period separately for each day of the week, A hot water storage type water heater described in any one of Appendix 1 to Appendix 7, wherein the control unit performs the boiling operation in accordance with the conditions set according to the hot water supply level divided by the day of the week. [Explanation of symbols]

[0059] 1 hot water storage tank, 1a first position, 1b second position, 1c hot water inlet outlet, 1d hot water inlet, 2 heat pump unit, 3 heating circulation circuit, 4 HP circulation pump, 5a first temperature sensor, 5b second temperature sensor, 5c third temperature sensor, 5d fourth temperature sensor, 5e fifth temperature sensor, 5f sixth temperature sensor, 5g seventh temperature sensor, 6 hot water storage tank temperature sensor, 7 general hot water supply side electric mixing valve, 7a hot water side inlet, 7b cold water side inlet, 7c hot water outlet, 8 high temperature piping, 9 water supply pipe, 9a water supply pipe, 9b water supply pipe, 10 first hot water supply pipe, 11 bath hot water supply side electric mixing valve, 11a hot water side inlet, 11b cold water side inlet, 11c hot water outlet, 12 bath side circulation circuit, 13 Bath on / off valve, 14 bath circulation pump, 15 heat exchanger, 16 first tank circulation piping, 17 water inlet switching valve, 18 second hot water supply pipe, 19 hot water supply flow rate sensor, 20 hot water supply temperature sensor, 21 bath flow rate sensor, 22 bath temperature sensor, 23 water supply temperature sensor, 24 control unit, 24a required heat quantity prediction means, 24b time zone division means, 24c hot water supply level setting means, 24d boiling end condition setting means, 25 remote control, 25a display unit, 26 hot water outlet switching valve, 27 medium temperature return switching valve, 28 medium temperature extraction switching valve, 28a medium temperature inlet, 28b low temperature inlet, 28c water outlet, 29 medium temperature return piping, 30 medium temperature piping, 31 bath heat recovery piping, 32 Bath heat recovery piping, 40 hot water storage tank unit, 41 low-temperature piping, 42 first water supply piping, 43 first hot water piping, 45 third hot water piping, 46 fourth hot water piping, 48 HP supply piping, 49 HP return piping, 50 second tank circulation piping, 51 second water supply piping

Claims

1. a hot water storage tank unit with a built-in hot water storage tank; a heating means for heating the water in the hot water storage tank; a time zone dividing means for dividing one day into a plurality of time zones; a hot water supply level setting means for setting the hot water supply amount predicted for each of the time periods divided by the time period dividing means as the hot water supply level for the time period; a control unit that operates the heating means to control a boiling operation for storing hot water in the hot water storage tank; A boiling end condition setting means for setting conditions for the boiling operation so that the boiling operation corresponding to the hot water supply level set by the hot water supply level setting means is completed by the start of the time period; Equipped with The control unit performs the boiling operation in accordance with the conditions set by the boiling end condition setting means.

2. a hot water storage tank unit with a built-in hot water storage tank; a heating means for heating the water in the hot water storage tank; a hot water supply level setting means for setting the hot water supply amount predicted for each time period of the day as the hot water supply level for that time period; a time zone dividing means for dividing one day into a plurality of time zones according to the difference in the hot water supply level set by the hot water supply level setting means; a control unit that operates the heating means to control a boiling operation for storing hot water in the hot water storage tank; A boiling end condition setting means for setting conditions for the boiling operation so that the boiling operation corresponding to the hot water supply level set by the hot water supply level setting means is completed by the start of the time period divided by the time period dividing means; Equipped with The control unit performs the boiling operation in accordance with the conditions set by the boiling end condition setting means.

3. 2. The hot water storage type water heater according to claim 1, wherein the time zone dividing means is capable of dividing a day into fixed time periods.

4. 2. The hot water storage type water heater according to claim 1, wherein the time zone dividing means is capable of dividing a day into variable time periods set by a user.

5. 5. The hot water storage type water heater according to claim 1, wherein the hot water supply level setting means allows the hot water supply level for each time period to be selected from a plurality of preset fixed values.

6. 5. The hot water storage type water heater according to claim 1, wherein the hot water supply level setting means allows a user to change the hot water supply level for each time period.

7. A hot water storage type water heater as described in any one of claims 1 to 4, which is equipped with a switching means that can switch between a ``boiling operation mode regardless of day or night'' that uses the boiling operation conditions set by the boiling end condition setting means, and a ``boiling operation mode using late-night power'' that performs the boiling operation during late-night hours depending on the hot water supply level during daytime hours.

8. Equipped with a calendar function that keeps track of the days of the week, The boiling end condition setting means recognizes the hot water supply level for each time period separately for each day of the week, A hot water storage type water heater as described in any one of claims 1 to 4, wherein the control unit performs the boiling operation in accordance with the conditions set according to the hot water supply level divided by the day of the week.

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