US-20260126211-A1 - HOT WATER SUPPLY SYSTEM AND HOT WATER SUPPLY METHOD

US20260126211A1US 20260126211 A1US20260126211 A1US 20260126211A1US-20260126211-A1

Abstract

A hot water supply system includes: an obtainer that obtains (i) a first boiling amount for each of a plurality of water heaters and (ii) a reference power of a housing complex in which the plurality of water heaters are provided, the reference power being from a second time slot having a cheap electricity rate; a determiner that, when determining, based on the plurality of first boiling amounts, that a demand power of the housing complex will exceed the reference power if the plurality of water heaters start boiling simultaneously in the second time slot, determines, prior to the second time slot, a schedule that, of a first and second water heater, delays a start of boiling by the second water heater, for which the first boiling amount is lower; and a controller that controls boiling by the water heaters in the second time slot based on the schedule determined.

Inventors

Noriyoshi Shimizu
Kazue Fusakawa
Fumiaki Suzuki
Atsuo Okaichi

Assignees

PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.

Dates

Publication Date: 20260507
Application Date: 20230523
Priority Date: 20220623

Claims (17)

1 . A hot water supply system comprising: an obtainer that obtains (i) a first boiling amount for each of a plurality of water heaters and (ii) a reference power of a housing complex in which the plurality of water heaters are provided, the reference power being from a second time slot having a cheaper electricity rate than a first time slot; a determiner that, when determining, based on the plurality of first boiling amounts obtained, that a demand power of the housing complex as a whole will exceed the reference power obtained if the plurality of water heaters start boiling simultaneously in the second time slot, determines, prior to the second time slot, a schedule that, of a first water heater and a second water heater included in the plurality of water heaters, delays a start of boiling by the second water heater, for which the first boiling amount is lower than the first water heater; and a controller that controls boiling by the plurality of water heaters in the second time slot based on the schedule determined.
2 . The hot water supply system according to claim 1 , wherein the first time slot is a time slot immediately following the second time slot, the obtainer obtains, for each of the plurality of water heaters, a second boiling amount based on a first expected usage amount of hot water in the first time slot, and the determiner determines the plurality of second boiling amounts obtained, as boiling amounts for corresponding ones of the plurality of water heaters in the second time slot.
3 . The hot water supply system according to claim 1 , wherein the obtainer obtains first information indicating a usage state of the hot water at a time when the schedule was determined, or a second expected usage amount of the hot water in the second time slot, of the second water heater for which the start of the boiling has been delayed by the schedule determined, and when it is determined that the second water heater will run out of hot water based on the first information obtained or the second expected usage amount obtained, the determiner updates the schedule to expedite the start of the boiling by the second water heater.
4 . The hot water supply system according to claim 1 , wherein the obtainer obtains second information indicating a third expected usage amount of the hot water by each of the plurality of water heaters in each of times, and when, based on the schedule determined and the second information obtained, it is determined that a third water heater, for which a time from a planned end time of boiling to a planned usage time of hot water exceeds a reference time, is present among the plurality of water heaters, the determiner updates the schedule to cause the third water heater to temporarily stop after boiling and then boil again in the second time slot.
5 . The hot water supply system according to claim 1 , wherein after the schedule has been determined, the obtainer obtains, in the second time slot, a first used power used by electrical equipment in the housing complex aside from the plurality of water heaters at a present time, and based on the plurality of first boiling amounts obtained and the first used power obtained, the determiner updates the schedule to ensure that the demand power of the housing complex as a whole does not exceed the reference power obtained and boiling is performed in order from a water heater, among the plurality of water heaters, for which the first boiling amount is highest.
6 . The hot water supply system according to claim 1 , wherein when a planned end time of the boiling by the second water heater, for which the start of the boiling has been delayed by the schedule determined, falls within the first time slot, an increase in an electricity rate caused by the planned end time falling within the first time slot, compared to the electricity rate when the planned end time falls within the second time slot, is taken as a first price increase, an increase in the electricity rate caused by the demand power exceeding the reference power obtained, due to the boiling by the second water heater being performed to cause the planned end time to fall within the second time slot, is taken as a second price increase, and the determiner increases the reference power and updates the schedule to cause the planned end time to fall within the second time slot when the second price increase is lower than the first price increase.
7 . The hot water supply system according to claim 1 , wherein when a planned end time of the boiling by the second water heater, for which the start of the boiling has been delayed by the schedule determined, falls within the first time slot, an increase in an electricity rate caused by the planned end time falling within the first time slot, compared to the electricity rate when the planned end time falls within the second time slot, is taken as a first price increase, an increase in the electricity rate caused by the demand power exceeding the reference power obtained, due to the boiling by the second water heater being performed to cause the planned end time to fall within the second time slot, is taken as a second price increase, and as a refund amount to an owner of the second water heater, the determiner: outputs a first refund amount that is the first price increase, or calculates and outputs a second refund amount that is a value obtained by multiplying a sum of the first price increase and the second price increase by a predetermined percentage.
8 . The hot water supply system according to claim 7 , wherein the obtainer obtains a refund instruction that is an instruction from the owner, the refund instruction indicates that the first refund amount has been selected as the refund amount, or indicates that the second refund amount has been selected as the refund amount and indicates a numerical value of the predetermined percentage, and the determiner calculates and outputs the refund amount based on the refund instruction obtained.
9 . The hot water supply system according to claim 8 , wherein the determiner increases the reference power and updates the schedule to cause the planned end time to fall within the second time slot when the second price increase is lower than a sum of the first price increase and the refund amount.
10 . The hot water supply system according to claim 8 , wherein when a plurality of the second water heaters are provided, the obtainer obtains the refund instruction from each of a plurality of the owners, and the determiner: calculates the refund amount to each of the plurality of the owners based on the plurality of refund instructions obtained; and updates the schedule to delay the start of the boiling by the second water heater owned by the owner for which the refund amount, among the plurality of refund amounts calculated, is lowest.
11 . The hot water supply system according to claim 1 , wherein the obtainer obtains, in the second time slot, a boiling instruction for a fourth water heater included in the plurality of water heaters, from an owner of the fourth water heater, and when it is determined, based on the boiling instruction obtained, that the demand power of the housing complex as a whole will exceed the reference power obtained if the fourth water heater starts boiling, the determiner updates the schedule to stop boiling by a water heater, among the plurality of water heaters, that is boiling, and start boiling by the fourth water heater.
12 . The hot water supply system according to claim 1 , wherein prior to the second time slot, the obtainer obtains a second used power based on an expected usage amount, in the second time slot, of electrical equipment in the housing complex aside from the plurality of water heaters, and when it is determined, based on the plurality of first boiling amounts obtained and the second used power obtained, that the demand power of the housing complex as a whole will, in the second time slot, exceed the reference power obtained, the determiner updates the schedule to stop boiling by the plurality of water heaters.
13 . The hot water supply system according to claim 1 , wherein after the schedule has been determined, the obtainer obtains, in the second time slot, a first used power used by electrical equipment in the housing complex aside from the plurality of water heaters at a present time, and when it is determined, based on the plurality of first boiling amounts obtained and the first used power obtained, that the demand power of the housing complex as a whole will, in the second time slot, exceed the reference power obtained, the determiner updates the schedule to stop boiling by the plurality of water heaters.
14 . The hot water supply system according to claim 1 , wherein when it is determined, based on the schedule determined and the reference power obtained, that in the second time slot, the demand power of the housing complex as a whole will exceed the reference power obtained, the determiner updates the schedule to supply power to the housing complex from power supply equipment included in the housing complex.
15 . The hot water supply system according to claim 1 , wherein when a planned end time of the boiling by the second water heater, for which the start of the boiling has been delayed by the schedule determined, falls within the first time slot, the determiner updates the schedule to supply power from power supply equipment included in the housing complex for the boiling by the second water heater in the first time slot.
16 . The hot water supply system according to claim 1 , wherein when boiling by a fifth water heater included in the plurality of water heaters is to be performed in the first time slot, a price when the boiling by the fifth water heater is performed using power supplied by a power company is taken as a first price, a price required to recharge charging equipment provided in the housing complex, when the boiling by the fifth water heater is performed using power with which the charging equipment has been charged, is taken as a second price, and when a selling price of power required for the boiling by the fifth water heater, when the power required has been generated by solar power generation equipment included in the housing complex, is taken as a third price, the determiner determines boiling control information to: cause the fifth water heater to boil using the power supplied by the power company, when the first price is lowest among the first price, the second price, and the third price; cause the fifth water heater to boil using the power with which the charging equipment has been charged, when the second price is lowest among the first price, the second price, and the third price; and cause the fifth water heater to boil using the power generated by the solar power generation equipment, when the third price is lowest among the first price, the second price, and the third price, and the controller controls boiling by the fifth water heater based on the boiling control information determined.
17 . A hot water supply method comprising: obtaining (i) a first boiling amount for each of a plurality of water heaters, and (ii) a reference power of a housing complex in which the plurality of water heaters are provided, the reference power being from a second time slot having a cheaper electricity rate than a first time slot; when it is determined, based on the plurality of first boiling amounts obtained, that a demand power of the housing complex as a whole will exceed the reference power obtained if the plurality of water heaters start boiling simultaneously in the second time slot, determining, prior to the second time slot, a schedule that, of a first water heater and a second water heater included in the plurality of water heaters, delays a start of boiling by the second water heater, for which the first boiling amount is lower than the first water heater; and controlling boiling by the plurality of water heaters in the second time slot based on the schedule determined.

Description

TECHNICAL FIELD The present invention relates to a hot water supply system and a hot water supply method. BACKGROUND ART Patent Literature (PTL) 1 discloses a storage-type water heater. Such a storage-type water heater generally stores hot water boiled during a time slot when electricity rates are low in a storage tank, and then supplies that hot water as necessary. The time slot when electricity rates are low is, for example, a nighttime time slot. CITATION LIST Patent Literature [PTL 1] Japanese Unexamined Patent Application Publication No. 2012-225601 SUMMARY OF INVENTION Technical Problem A plurality of the water heaters disclosed in PTL 1 may be installed in a housing complex, for example. In such a case, if the water heaters start boiling at the same time during a nighttime time slot, the overall demand power of the housing complex at that time may become extremely high. Incidentally, the types of contracts for supplying power to a housing complex include a high-voltage collective power reception contract. In such a contract, the management company or management association of the housing complex enters into a contract with the power company, and a user in each household then enters into a contract with the manager or management association of the housing complex. In a high-voltage collective power reception contract, a reference power, which is a reference value (an upper limit value) for the overall demand power of the housing complex, is set. If the reference power is exceeded, a contract in which the reference power is increased and the electricity rate is raised will be required in the next fiscal year. Accordingly, if the overall demand power of a housing complex becomes extremely high due to boiling by a plurality of water heaters as described above, the demand power (and more specifically, a maximum value of the demand power) may exceed the reference power and cause the electricity rate to rise as a result. Problems such as breakers tripping also occur when the demand power increases. The present invention provides a hot water supply system and the like capable of suppressing the maximum value of the overall demand power of a housing complex. Solution to Problem A hot water supply system according to one aspect of the present invention includes: an obtainer that obtains (i) a first boiling amount for each of a plurality of water heaters and (ii) a reference power of a housing complex in which the plurality of water heaters are provided, the reference power being from a second time slot having a cheaper electricity rate than a first time slot; a determiner that, when determining, based on the plurality of first boiling amounts obtained, that a demand power of the housing complex as a whole will exceed the reference power obtained if the plurality of water heaters start boiling simultaneously in the second time slot, determines, prior to the second time slot, a schedule that, of a first water heater and a second water heater included in the plurality of water heaters, delays a start of boiling by the second water heater, for which the first boiling amount is lower than the first water heater; and a controller that controls boiling by the plurality of water heaters in the second time slot based on the schedule determined. A hot water supply method according to one aspect of the present invention includes: obtaining (i) a first boiling amount for each of a plurality of water heaters, and (ii) a reference power of a housing complex in which the plurality of water heaters are provided, the reference power being from a second time slot having a cheaper electricity rate than a first time slot; when it is determined, based on the plurality of first boiling amounts obtained, that a demand power of the housing complex as a whole will exceed the reference power obtained if the plurality of water heaters start boiling simultaneously in the second time slot, determining, prior to the second time slot, a schedule that, of a first water heater and a second water heater included in the plurality of water heaters, delays a start of boiling by the second water heater, for which the first boiling amount is lower than the first water heater; and controlling boiling by the plurality of water heaters in the second time slot based on the schedule determined. Advantageous Effects of Invention The hot water supply system and the like of the present invention make it possible to suppress the maximum value of the overall demand power of a housing complex. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a block diagram illustrating the functional configuration of a hot water supply system according to Embodiment 1. FIG. 2 is a flowchart of Operation Example 1 according to Embodiment 1. FIG. 3 is a diagram illustrating a schedule according to Embodiment 1. FIG. 4 is a flowchart of Operation Example 2 according to Embodiment 1. FIG. 5 is a flowchart of Operation Example 3 according to Embodiment 1. FIG. 6 is a flowchart of Operatio