Storage-type hot water heater

Abstract

To solve problems in a storage type hot water supply device that in a method of boiling up a small amount of water at night so as to secure hot water before a time when a daytime boiling-up operation is executed, a daytime boiling-up operation factor is degraded, as a boiling-up amount in the boiling-up operation utilizing photovoltaic power generation is reduced in a case of using hot water not so much, and further a risk of running-out of hot water is generated when the boiling-up operation at night is stopped without thinking.SOLUTION: A control device 29 is provided with demand determination means 34 for determining whether or not it is necessary to boil up a night boiling-up amount before a daytime start time, and when the demand determination means 34 determines unnecessity of boiling-up, the control device 29 inhibits the boiling-up operation before the daytime start time regardless of the set night time boiling-up amount, thus a daytime boiling-up operation factor can be improved while suppressing a risk of running-out of hot water.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to improving the operating efficiency of a storage type hot water heater having a solar power generation system. [Background technology]

[0002] BACKGROUND ART Conventionally, a hot water storage type water heater linked to a solar power generation system is known to efficiently heat water during the daytime using the electricity generated by the solar power generation system.

[0003] In recent years, electricity rate plans that make the electricity rates the same during the daytime and at night (late at night) have become known for users who install solar power generation systems and hot water storage systems.Hot water storage systems that work in conjunction with solar power generation systems perform heating operation using electricity generated by the solar power generation system during the daytime when the sun is up, and also perform heating operation during the daytime when the sun is not up at the same electricity rate as heating operation during the nighttime (late at night).As a result, daytime operation hot water storage systems are known that can reduce electricity bills by using electricity generated by the solar power generation system to heat water during the daytime when the sun is up,

[0004] Furthermore, in a storage-type hot water supply device with a solar power generation system that performs heating operation during the daytime, as in Patent Document 1, even if hot water is needed before the daytime heating operation (for example, early in the morning), there is a possibility that sufficient hot water may not be secured before the heating operation begins, so a control method has been known in which a small amount of hot water is heated during the nighttime (late at night). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-67381 Summary of the Invention [Problem to be solved by the invention]

[0006] However, with this type of daytime operation hot water storage type water heater, there is a method of heating a small amount of water at night to secure hot water before the daytime heating operation.However, during times when not much hot water is used, the amount of water heated by the solar power generation heating operation is reduced, which creates an issue where the daytime heating operation rate is poor.

[0007] Furthermore, if the rate of daytime heating operation is reduced simply in order to increase the rate of daytime heating operation, there is a problem that if the hot water in the hot water storage tank is used before the daytime heating operation, the hot water may run out depending on the amount of usage. Therefore, improving the rate of daytime heating operation and reducing the risk of running out of hot water have become issues. [Means for solving the problem]

[0008] The hot water storage type hot water supply device according to the present invention includes a hot water storage tank for storing hot water, a heating means capable of heating the hot water using privately generated electricity obtained from a solar power generation system, a control device for controlling a boiling operation in which the heating means heats the hot water in the hot water storage tank, a target boiling amount calculation means for calculating a target boiling amount to be boiled by the end of a daytime period on the following day based on the amount of hot water storage required on the following day, and a specific amount of hot water stored in the hot water storage tank before the start of the daytime period that is a period from before the start of the daytime period to before the end of the daytime period. In a hot water storage type hot water supply device equipped with a nighttime boiling amount calculation means for calculating a nighttime boiling amount that boils a portion of the target boiling amount before the start time of the daytime period so that the amount of hot water used is equal to or greater than the amount based on past usage records during that period, the control device is provided with a demand determination means for determining whether or not the nighttime boiling amount needs to be boiled before the start time of the daytime period, and if the demand determination means determines that boiling is not necessary, the control device does not perform boiling operation before the start time of the daytime period regardless of the set nighttime boiling amount.

[0009] In addition, the control device is capable of acquiring the detection value of an outdoor air temperature sensor that detects the outdoor air temperature, and if the outdoor air temperature is equal to or higher than a predetermined outdoor air temperature and the amount of hot water based on past usage during the specific period is equal to or less than a predetermined amount, the demand determination means determines that there is no need to heat the water, and the control device does not perform heating operation before the start time of the daytime period.

[0010] In addition, the control device is capable of acquiring the detection value of a water supply temperature sensor that detects the water supply temperature, and if the water supply temperature is higher than a predetermined water temperature and the amount of hot water based on past usage during the specific period is lower than a predetermined amount, the demand determination means determines that there is no need to heat the water, and the control device does not perform heating operation before the start time of the daytime period. [Effects of the Invention]

[0011] In the storage-type hot water supply device of the present invention, when the demand determination means determines that the demand for hot water is low, the control device does not perform nighttime boiling operation regardless of the nighttime boiling amount calculated by the nighttime boiling amount calculation means, and instead increases the daytime boiling amount, thereby reducing the risk of running out of hot water while improving the daytime boiling operation rate. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a system configuration diagram of a hot water supply system including a storage type hot water supply device according to an embodiment of the present invention. [Figure 2] A table showing the setting conditions for the end-of-boiling TH level for nighttime boiling volume. [Figure 3] 10 is a flowchart illustrating processing executed by a nighttime boiling amount calculation means and a demand determination means. [Figure 4] 4 is a flowchart illustrating control of the heating operation executed by the control device. DETAILED DESCRIPTION OF THE INVENTION

[0013] An embodiment of a hot water storage type water heater 1 according to the present invention will be described with reference to the accompanying drawings.

[0014] FIG. 1 is a system configuration diagram of a hot water supply system 100 including a storage type hot water supply device 1 in this embodiment.

[0015] The hot water supply system 100 includes a distribution board 2, a solar power generation system 3, and a storage type hot water supply device 1 (hereinafter simply referred to as "hot water supply device 1").

[0016] The distribution board 2 is installed in a building such as a house (hereinafter simply referred to as "the house") together with the solar power generation system 3 and the hot water supply system 1. The distribution board 2 is connected to a commercial power source 2a and the solar power generation system 3. The distribution board 2 supplies commercial power supplied from the commercial power source 2a and privately generated power generated by the solar power generation system 3 to the hot water supply system 1 used in the house and to electrical load devices in the house other than the hot water supply system 1, such as an air conditioner (hereinafter simply referred to as "air conditioner, etc. 6" in the following explanation and in FIG. 1).

[0017] The solar power generation system 3 includes a solar power generation panel 4 and an inverter 5. The solar power generation panel 4 is installed on the roof of a house or the like. The inverter 5 converts the power generated by the solar power generation panel 4 into AC power.

[0018] The hot water supply device 1 includes a hot water storage tank 7, a heat pump unit 16, a circulation circuit 24, a remote control 30, and a control device 29.

[0019] The hot water storage tank 7 stores hot water to be supplied to hot water supply terminals such as a bath, a kitchen, etc. The hot water storage tank 7 has a water supply pipe 8, a hot water outlet pipe 9, a water supply bypass pipe 10, a hot water supply pipe 12, and a hot water temperature sensor 15.

[0020] A water supply pipe 8 is connected to the hot water storage tank 7 at its bottom and supplies water to the hot water storage tank 7. A hot water outlet pipe 9 is connected to the hot water storage tank 7 at its top and outputs hot water from the hot water storage tank 7. A water supply bypass pipe 10 is a pipe branching off from the water supply pipe 8 and is connected to the hot water outlet pipe 9 via a mixing valve 11. The mixing valve 11 mixes the hot water from the hot water outlet pipe 9 and the water from the water supply bypass pipe 10 to reach the hot water supply setting temperature set by the remote control 30.

[0021] Hot water supply pipe 12 supplies hot water supplied via mixing valve 11 to a hot water supply terminal. Hot water supply pipe 12 has hot water supply flow rate sensor 13 and hot water supply temperature sensor 14. Hot water supply flow rate sensor 13 detects the hot water supply flow rate and outputs a corresponding detection signal to control device 29. Hot water supply temperature sensor 14 detects the hot water supply temperature and outputs a corresponding detection signal.

[0022] The hot water temperature sensor 15 detects the temperature of the hot water in the hot water tank 7 and outputs a corresponding detection signal to the control device 29. A plurality of hot water temperature sensors 15 are provided at different height positions on the side of the hot water tank 7. When each of these hot water temperature sensors 15 detects a hot water temperature equal to or higher than a predetermined threshold value that is set in advance corresponding to the temperature of hot water in a sufficiently heated state, it outputs a corresponding detection signal to the control device 29. The control device 29 detects the amount of hot water in the hot water tank 7 that is in a sufficiently heated state (i.e., the amount of hot water stored) based on the number of hot water temperature sensors 15 that output detection signals (here, seven sensors TH1 to TH7 are provided).

[0023] The heat pump unit 16 is a heating means that operates using privately generated electricity and commercial electricity and exchanges heat with hot water to boil the water. The heat pump unit 16 includes a compressor 17, a water-refrigerant heat exchanger 18, an expansion valve 19, an air heat exchanger 20, a refrigerant pipe 23, and a blower 21.

[0024] The compressor 17 compresses the refrigerant to a high temperature and high pressure and transports it. The water-refrigerant heat exchanger 18 exchanges heat between the high temperature, high pressure refrigerant and water from the hot water storage tank 7. The expansion valve 19 decompresses and expands the refrigerant that has undergone heat exchange in the water-refrigerant heat exchanger 18. The air heat exchanger 20 exchanges heat between outside air and the low pressure refrigerant, evaporating the low pressure refrigerant. The refrigerant pipe 23 circulates the refrigerant through the compressor 17, the water-refrigerant heat exchanger 18, the expansion valve 19, and the air heat exchanger 20. The blower 21 blows outside air to the air heat exchanger 20.

[0025] The heat pump unit 16 also has a discharge temperature sensor 22 and an outside air temperature sensor 28. The discharge temperature sensor 22 detects the temperature of the refrigerant discharged from the compressor 17 and outputs a corresponding detection signal to the control device 29. The outside air temperature sensor 28 detects the outside air temperature and outputs a corresponding detection signal to the control device 29.

[0026] The circulation circuit 24 circulates the hot water in the hot water storage tank 7 between the hot water storage tank 7 and the water-refrigerant heat exchanger 18. The circulation circuit 24 has a heating supply pipe 25a, a heating return pipe 25b, a heating circulation pump 26, and a boiling temperature sensor 27.

[0027] Heating supply pipe 25a connects the bottom of hot water storage tank 7 with the water-side inlet of water-refrigerant heat exchanger 18. Heating return pipe 25b connects the water-side outlet of water-refrigerant heat exchanger 18 with the top of hot water storage tank 7. Heating circulation pump 26 is arranged on heating supply pipe 25a and circulates hot water. Boiling temperature sensor 27 is arranged on heating return pipe 25b and outputs a detection signal to control device 29.

[0028] Remote control 30 receives instructions from the user regarding water heating device 1, such as the set temperature of hot water to be supplied to the water heating terminal.

[0029] Control device 29 has a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc., and stores various programs and data necessary for controlling control device 29. Control device 29 controls the operation of water heating apparatus 1 overall in accordance with the various programs. Control device 29 is connected to remote control 30 and communicates with remote control 30 bidirectionally.

[0030] The control device 29 controls the boiling operation for boiling the hot water in the hot water storage tank 7 based on information learned from the calculation means and determination means described below and the history of the amount of hot water used.

[0031] Next, the time periods for water heating operation will be explained. First, a day is divided into the morning and afternoon period from 7:00 to 17:00 (hereinafter simply referred to as the daytime period), the nighttime period from 17:00 to 23:00, and the late-night period from 23:00 to 7:00. The daytime water heating operation period is set to 9:00 to 17:00 (this can vary depending on the season), taking into account power generation using solar light. The nighttime water heating operation period is set to 23:00 to 7:00, a time period when electricity usage is low.

[0032] The control device 29 includes a target boiling amount calculation means 31, a usage amount record learning unit 32, a nighttime boiling amount calculation means 33, and a demand determination means .

[0033] The target boiling amount calculation means 31 calculates the target boiling amount, which is the total amount to be boiled from the start time (7:00 in this example) to the end time (17:00 in this example) of the daytime period, based on the amount of hot water storage required for the next day from the hot water usage record learned by the usage record learning unit 32. The control device 29 calculates the time required to perform the boiling operation during this daytime period, and controls the operation so that the boiling operation is completed as late as possible. The user may also use the remote control 30 to arbitrarily set the start time or end time of the boiling operation.

[0034] The usage record learning unit 32 receives the detection signal (indicating the amount of hot water supplied) from the hot water supply flow rate sensor 13, the detection signal (indicating the hot water supply temperature) from the hot water supply temperature sensor 14, and the detection signal (indicating the water supply temperature) from the water supply temperature sensor (not shown), converts the input hot water supply amount into a usage amount at a predetermined temperature (e.g., 43°C) while corresponding to the hot water supply temperature, and learns the amount of hot water used by the user each day over a predetermined period of the past (e.g., seven days) and the amount of hot water used by the user during a specific period from before the start of the daytime period to before the end of the daytime period (3:00 to 15:00 in this example). The learning also includes information about hot water usage, such as whether a large amount of hot water in the hot water storage tank 7 was used during the specific period to fill a bathtub (not shown) with hot water or whether a reheating operation was performed to heat the bathtub by exchanging heat with the hot water in the hot water storage tank 7.

[0035] The nighttime boiling amount calculation means 33 calculates a nighttime boiling amount by boiling a portion of the target boiling amount before the start of the daytime period so that the amount of hot water stored in the hot water storage tank 7 before the start of the daytime period is equal to or greater than the amount of hot water based on the user's past usage during a specific period learned by the usage amount history learning unit 32. Before the start of the daytime period means the start of the daytime period (7:00 in this case), and taking into account the heat radiation from the hot water storage tank 7, it is appropriate to complete the nighttime boiling operation slightly before the start of the daytime period (approximately 6:00 to 6:30). Also, although it is stated that the start of the daytime period is before the start of the daytime period (approximately 6:00 to 6:30), if the usage amount history learning unit 32 has learned that hot water was used earlier (at 5:00), the nighttime boiling operation may be performed earlier to be in time for the hot water usage.

[0036] In addition, if boiling operation is performed at night, the remaining boiling amount obtained by subtracting the nighttime boiling amount from the target boiling amount is set as the daytime boiling amount, and boiling operation is performed during the daytime for the daytime boiling amount.If boiling operation is not performed at night, the target boiling amount is set as the daytime boiling amount, and boiling operation is performed during the daytime for the daytime boiling amount (target boiling amount).

[0037] Furthermore, the nighttime boiling amount calculation means 33 appropriately changes and sets the boiling end TH level of the hot water storage tank 7 based on the calculated nighttime boiling amount. This boiling end TH indicates which of the hot water storage temperature sensors 15, TH1 to TH7, detects a hot water temperature equal to or higher than a predetermined threshold value to stop the boiling operation.

[0038] The details will be explained with reference to FIG. If the usage amount record learning unit 32 has learned that there has been a history of hot water filling or reheating, the nighttime boiling amount calculation means 33 sets the boiling end TH level to level 1. In the case of level 1, as shown in the distribution of boiling amounts in Figure 2, the hot water storage temperature sensor 15 that will end the boiling operation when it detects a predetermined high temperature is selected and set from the hot water storage temperature sensors 15 installed above and below the hot water storage tank 7, in order to boil 3 / 7 of the target boiling amount (up to TH5) during the night.

[0039] Furthermore, if the usage amount history learning unit 32 determines that the amount of hot water is equal to or greater than a first predetermined usage amount (e.g., 200 L), the nighttime boiling amount calculation means 33 sets the boiling end TH level to level 1, and if the usage amount history learning unit 32 determines that the amount of hot water is equal to or greater than a second predetermined usage amount (e.g., 100 L) and less than the first predetermined usage amount, the nighttime boiling amount calculation means 33 sets the boiling end TH level to level 2. In the case of level 2, as shown in the distribution of boiling amounts in Figure 2, the hot water storage temperature sensor 15 that terminates boiling operation when it detects a predetermined high temperature is selected and set from the hot water storage temperature sensors 15 provided above and below the hot water storage tank 7, in order to boil 2 / 7 of the target boiling amount (up to TH6) during the night.

[0040] Furthermore, if the usage amount history learning unit 32 determines that the amount of hot water used is less than a second predetermined usage amount (for example, 100 L), the end-of-boiling TH level is set to level 3. In the case of level 3, as shown in the distribution of boiling amounts in Fig. 2, a hot water storage temperature sensor 15 that terminates the boiling operation when it detects a predetermined high temperature is selected and set from the hot water storage temperature sensors 15 provided above and below the hot water storage tank 7, in order to boil 1 / 7 of the target boiling amount (up to TH7) during the night.

[0041] The demand determination means 34 determines whether or not it is necessary to heat the nighttime boiling amount before the start of the daytime period, and based on the determination result, the control device 29 determines whether or not to perform the nighttime boiling operation.

[0042] The conditions for the judgment by the demand judgment means 34 are to judge whether or not the nighttime heating operation is possible depending on whether the demand for hot water is low or high. Specifically, when the periodically detected outside air temperature (hereinafter simply referred to as outside air temperature) is below a predetermined outside air temperature, it is judged to be a period when the demand for hot water is high, and when the outside air temperature is above the predetermined outside air temperature, it is judged to be a period when the demand for hot water is low (here, the predetermined outside air temperature is 20 degrees).

[0043] FIG. 3 is a flowchart illustrating in detail the processing executed by the nighttime boiling amount calculation means 33 and the demand determination means 34.

[0044] This process is repeatedly executed every day at the start of the late-night period, for example, while water heating apparatus 1 is running.

[0045] When the late-night period begins, first in step S1, the control device 29 checks the amount of hot water used by the user during the specific period and the user's use of filling or reheating the water, based on the learning content learned by the usage amount learning unit 32. If there is a history of filling or reheating the water, the determination in step S1 is satisfied (S1 is Yes), and the process proceeds to step S2.

[0046] In step S2, the nighttime boiling amount calculation means 33 sets the boiling end TH level for the nighttime boiling amount to be boiled to level 1. Then, the process proceeds to step S9, which will be described later.

[0047] On the other hand, if there is no record of filling or reheating the water in step S1, the condition of step S1 is not satisfied (S1 is No), and the process proceeds to step S3.

[0048] In step S3, the control device 29 determines whether the amount of water used by the user during the specific period (3:00 AM to 3:00 PM) was equal to or greater than the first predetermined amount of water used (200 L) based on the learning content learned by the usage amount record learning unit 32. If the amount of water used was equal to or greater than the first predetermined amount of water used (200 L), the determination in step S3 is satisfied (Yes in S3), the process proceeds to step S2, and the nighttime boiling amount calculation means 33 sets the end-of-boiling TH level to level 1. Then, the process proceeds to step S11, which will be described later.

[0049] On the other hand, if the amount used is less than the first predetermined amount used (200 L) in step S3, the condition of step S3 is not satisfied (No in S3), and the process proceeds to step S4.

[0050] In step S4, the control device 29 determines whether the amount of water used by the user during the specific period was equal to or greater than a second predetermined amount of water use (100 L) based on the learning content learned by the usage amount record learning unit 32. If the amount of water used was equal to or greater than the second predetermined amount of water use (100 L), the condition of step S4 is satisfied (Yes in S4), and the process proceeds to step S5.

[0051] In step S5, the nighttime boiling amount calculation means 33 sets the boiling end TH level to level 2. Thereafter, the process proceeds to step S11, which will be described later.

[0052] On the other hand, if the amount used is less than the second predetermined amount used (100 L) in step S4, the condition of step S4 is not satisfied (No in step S4), and the process proceeds to step S6.

[0053] In step S6, the nighttime boiling amount calculation means 33 sets the end-of-boiling TH level to level 3.

[0054] In this way, the nighttime boiling amount calculation means 33 adjusts the amount of hot water and cold water based on the user's past usage over a specific period learned by the usage amount history learning unit 32, and the final boiling TH level (levels 1 to 3) according to the usage history of filling the water or reheating, thereby adjusting the nighttime boiling amount for nighttime boiling operation using commercial electricity and securing time for daytime boiling operation when self-generated electricity from solar power can be expected, thereby preventing hot water shortages, increasing the daytime boiling operation rate, and reducing electricity costs.

[0055] Next, when the end-of-boiling TH level is set to level 3 in step S6, the demand determination means 34 determines whether the demand for hot water is high or low (S7).

[0056] Here, the demand determination means 34 determines whether the outdoor air temperature detected by the outdoor air temperature sensor 28 is above a predetermined outdoor air temperature (here, above 20 degrees) (S7), and if the outdoor air temperature is above the predetermined outdoor air temperature, the demand determination means 34 determines that it is a period when demand for hot water is low (S8).

[0057] Then, when the demand determination means 34 determines that it is a period when the demand for hot water supply is low, the control device 29 sets the water heating operation not to be performed at night (S9).

[0058] If the outside air temperature is equal to or lower than the predetermined outside air temperature, the demand determination means 34 determines that it is a period of high demand for hot water (S10). Next, based on the detected value of the hot water storage temperature sensor 15, it is confirmed whether the required amount of hot water for each of the set end-of-boiling TH levels (levels 1 to 3) has been secured (S11), and if the required amount of hot water for each of the set end-of-boiling TH levels (levels 1 to 3) has been secured (No in S11), the control device 29 sets the nighttime heating operation not to be performed (S9).

[0059] Then, if the required amount of hot water for each set end-of-boiling TH level (levels 1 to 3) has not been secured (S11: Yes), it is set to perform nighttime boiling operation (S12), and the nighttime boiling amount calculation means 33 calculates the nighttime boiling amount so that the amount of hot water stored in the hot water storage tank 7 before the start of the daytime period is equal to or greater than the amount of hot water based on the user's past usage history during a specific period learned by the usage history learning unit 32, and the control device 29 calculates the nighttime boiling operation time required to boil the nighttime boiling amount before the start of the daytime period, and calculates the start time of the nighttime boiling operation by going back the nighttime boiling operation time from the end of the late night period (S12).

[0060] In this way, the demand determination means 34 determines that nighttime heating operation will not be performed when the amount of hot water used during a specific period is low at the end-of-heating TH level 3 and the demand for hot water is low.Therefore, the target boiling amount is heated up entirely during daytime heating operation using self-generated electricity generated by the solar power generation system 3, and the daytime heating operation rate can be improved on sunny days.

[0061] Next, the control of the boiling operation will be described in detail with reference to the flowchart of FIG. First, based on steps S9 and S12, it is determined whether or not the heating operation can be performed at night (S14).

[0062] If nighttime heating operation is required (Yes in S14), and the start time of the nighttime heating operation calculated in S13 is reached (Yes in S15), the control device 29 uses commercial power to perform heating operation for a portion of the hot water that needs to be heated, based on the set end-of-heating TH level (Levels 1 to 3) (S16). After that, if the detection value of the hot water storage temperature sensor 15 reaches the set end-of-heating TH level (Levels 1 to 3) (Yes in S17), the nighttime heating operation is ended (S18).

[0063] Also, in S14, if nighttime heating operation is not required (No in S14), S15 to S18 are omitted and the process proceeds to S19.

[0064] Then, when the start time of the daytime period (7:00 in this case) arrives (Yes in S19), the control device 29 calculates (S20) the boiling operation time required to boil the amount of hot water used by the user in one day, as learned by the usage amount history learning unit 32. At this time, if the nighttime boiling operation is being performed, the control device 29 calculates the time for the daytime boiling operation based on the amount of boiling required to boil the amount of hot water used in one day, minus the amount of boiling at night.

[0065] Then, the control device 29 determines the start time of the daytime boiling operation by counting back the calculated necessary boiling operation time from the end time of the boiling operation (here, 17:00) (S21).

[0066] When the start time of the heating operation determined in S22 is reached (S22 is Yes), the control device 29 carries out the daytime heating operation (S23), and when the amount of hot water reaches the required amount of hot water used (S24 is Yes), the control device 29 ends the daytime heating operation (S25).

[0067] In this way, when the demand determination means 34 determines that the demand for hot water is low, the control device 29 reduces the amount of water boiled at night and increases the amount of water boiled during the day when boiling operation is possible using the self-generated electricity obtained by the solar power generation system 3, thereby reducing the risk of running out of hot water while improving the daytime boiling operation rate.

[0068] Although the embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents as set forth in the claims.

[0069] For example, even if the demand determination means 34 determines that no heating operation should be performed at night, if the amount of hot water stored in the hot water storage tank 7 is extremely low, the control device 29 may determine that the amount of hot water stored has fallen below the minimum amount and perform heating operation, thereby preventing a shortage of hot water.

[0070] Furthermore, the conditions for determining whether the demand for hot water is high or low in the nighttime boiling amount calculation means of the demand determination means 34 are to determine whether the demand for hot water is high or low. In the embodiment, the determination is made by comparing the outside air temperature with a predetermined outside air temperature, but this is not limited to this. For example, the water supply temperature detected by a water supply temperature sensor (not shown) can be compared with a predetermined water supply temperature (here, the predetermined water supply temperature is 24 degrees), or in the case of a hot water storage type hot water supply device 1 equipped with a calendar function, the determination can be made as to whether the current season is summer, mid-season, or winter, or whether the amount of hot water used in the evening (from 3:00 p.m. to 11:00 p.m.) is high or low.

[0071] In addition, in the embodiment, the time for daytime heating operation is set back from the end time of the daytime period by the amount of time for heating operation, but heating operation may also be started from the start time of the daytime period, or the user may set any time using the remote control 30. [Explanation of symbols]

[0072] 1. Storage-type hot water supply system (hot water supply system) 3. Solar power generation system 7 Hot Water Tank 16 Heat pump unit 24 Circulation circuit 29 Control Device 30 Remote Control 31 Target boiling amount calculation means 32 Usage performance learning section 33 Means for calculating night boiling amount 34 Demand determination means

Claims

1. A hot water storage tank for storing hot water; a heating means capable of heating the hot water using privately generated electricity obtained from a solar power generation system; a control device that controls a boiling operation in which the heating means heats the hot water in the hot water storage tank; a target boiling amount calculation means for calculating a target boiling amount to be boiled by the end of the daytime period of the next day based on the amount of hot water stored for the next day; a nighttime boiling amount calculation means for calculating a nighttime boiling amount that boils a portion of the target boiling amount before the start time of the daytime period so that the amount of hot water stored in the hot water storage tank before the start time of the daytime period is equal to or greater than the amount of hot water used based on past usage records during a specific period from before the start time of the daytime period to before the end time of the daytime period, The control device is provided with a demand determination means for determining whether or not the nighttime boiling amount needs to be boiled before the start time of the daytime period, A hot water storage type hot water supply device characterized in that, when the demand determination means determines that there is no need to heat water, the control device does not perform heating operation before the start time of the daytime period regardless of the set nighttime heating amount.

2. the control device is capable of acquiring a detection value of an outside air temperature sensor that detects an outside air temperature; When the outside air temperature is equal to or higher than a predetermined outside air temperature and the amount of hot water based on past usage in the specific period is equal to or lower than a predetermined amount, the demand determination means determines that there is no need to heat the water; 2. The hot water storage type hot water supply device according to claim 1, wherein the control device is configured not to perform the heating operation before the start time of the daytime period.

3. the control device is capable of acquiring a detection value of a feed water temperature sensor that detects a feed water temperature, When the supply water temperature is equal to or higher than a predetermined water temperature and the amount of hot water based on past usage in the specific period is equal to or lower than a predetermined amount, the demand determination means determines that there is no need to boil the water; 2. The hot water storage type hot water supply device according to claim 1, wherein the control device is configured not to perform the heating operation before the start time of the daytime period.

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