Storage-type water heater

Abstract

To provide a storage-type water heater which can maintain a heat storage amount after a hot water filling operation even when a hot water storage temperature is lowered to store the heat.SOLUTION: A storage-type water heater according to the present disclosure includes: a heat source machine for heating water; a hot water storage tank for storing hot water heated by the heat source machine; and control means for controlling an operation of the heat source machine. The storage-type water heater can perform a hot water filling operation for filling hot water in a bathtub by mixing hot water flown out from the hot water storage tank and hot water flown out from the heat source machine. The control means is capable of: predicting a predicted hot water amount used after the hot water filling operation; calculating a hot water storage amount in the hot water storage tank which can be used for the hot water filling operation based on the current hot water storage amount in the hot water storage tank and the predicted hot water amount; and calculating the heating capacity of the heat source machine during the hot water filling operation by using the hot water storage amount in the hot water storage tank which can be used for the hot water filling operation, a temperature inside the hot water storage tank, a hot water filling amount, a hot water filling temperature, a supply water temperature, and a hot water filling time when the hot water storage amount in the hot water storage tank which can be used for the hot water filling operation is smaller than a hot water storage amount required for filling hot water in the bathtub.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] The conventional hot water storage type water heater disclosed in Patent Document 1 below comprises a heat pump cycle in which a compressor, a hot water heat exchanger, an expansion valve, and an evaporator are connected by piping, a hot water storage tank that stores liquid heated using the heat pump cycle, and a maximum heat amount control means that controls the heat amount of the heat pump cycle to be maximized. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-241206 Summary of the Invention [Problem to be solved by the invention]

[0004] One approach to improving energy efficiency is to lower the temperature of the hot water storage tank. However, such a hot water storage system has a problem in that the surplus hot water volume is small relative to the load, and therefore, sudden hot water usage before the bath is filled can cause the hot water to run out after it is filled.

[0005] The present disclosure has been made to solve the above-mentioned problems. The purpose of the present disclosure is to provide a hot water storage type water heater that can maintain the amount of heat stored after the hot water filling operation even when storing heat at a lower temperature than in the past. [Means for solving the problem]

[0006] The hot water storage type water heater of the present disclosure comprises a heat source unit that heats water, a hot water storage tank that stores hot water heated by the heat source unit, and a control means that controls the operation of the heat source unit, and is capable of performing a bath filling operation in which hot water flowing out of the hot water storage tank is mixed with hot water flowing out of the heat source unit to fill the bathtub.The control means predicts the predicted amount of hot water to be used after the bath filling operation, and calculates the amount of hot water stored in the hot water storage tank that can be used for the bath filling operation from the current amount of hot water stored in the hot water storage tank and the predicted amount of hot water.If the amount of hot water stored in the hot water storage tank that can be used for the bath filling operation is smaller than the amount of hot water required to fill the bathtub, the heating capacity of the heat source unit during the bath filling operation can be calculated using the amount of hot water stored in the hot water storage tank that can be used for the bath filling operation, the temperature in the hot water storage tank, the amount of hot water filled, the temperature of the water supply, and the time it takes to fill the bathtub. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide a hot water storage type water heater that can maintain the amount of heat stored after the hot water filling operation even when storing heat at a lower hot water temperature than conventionally. [Brief explanation of the drawings]

[0008] [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 in the first embodiment. [Figure 3] 2 is a diagram showing an example of a configuration for realizing the functions of a heat source machine control device, a water heater control device, or a remote control in the first embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment will be described with reference to the drawings. Common or corresponding elements in each drawing will be assigned the same reference numerals, and their description will be simplified or omitted. In the following description, the terms "water," "hot water," "warm water," "hot water," etc. generally refer to liquid water, and can include anything from cold water to hot water.

[0010] 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 as the difference from the calorific value of water at the same temperature as the water supplied from the water source. In this embodiment, the calorific value of hot water may be expressed in units of the volume 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.

[0011] As shown in Fig. 1, the hot water storage type water heater of this embodiment includes a heat source device 100 corresponding to a heating means for heating water, and a hot water storage unit 200 having a hot water storage tank 11. The heat source device 100 and the hot water storage unit 200 are connected via pipes 16a and 16k through which water flows, and electrical wiring (not shown). The hot water storage type water heater of this embodiment may be, for example, a home use one, or may be a commercial use one used in a store or facility, etc.

[0012] The heat source machine 100 has components such as a compressor 1, a water-refrigerant heat exchanger 2, an expansion valve 3, and an air heat exchanger 4, and is powered by electricity. These components are connected in a ring shape by piping or the like to form a refrigerant circuit 101 that circulates the refrigerant using the compressor 1. The refrigerant circuit 101 corresponds to a heat pump cycle that heats water. The water-refrigerant heat exchanger 2 exchanges heat between the water and the refrigerant and has a water inlet and outlet. In the following description, hot water heated by the heat source machine 100 may be referred to as "heated water." The water-refrigerant heat exchanger 2 heats water flowing in through the inlet with the refrigerant and discharges the heated water from the outlet. The air heat exchanger 4 exchanges heat between the air and the refrigerant. The heat source machine 100 further includes a fan 5 that blows outside air to the air heat exchanger 4.

[0013] In addition to the hot water storage tank 11, the hot water storage unit 200 is equipped with a circulation pump 6a, a reheating pump 6b, a switching valve 7, a switching valve 8, a switching valve 9, and a mixing valve 10. The circulation pump 6a circulates water (including heated water) through a hot water storage circuit 201 and a reheating circuit 202 (described below), and sends the water toward the inlet of the water-refrigerant heat exchanger 2. The circulation pump 6a constitutes part of the hot water storage circuit 201 and the reheating circuit 202. The reheating pump 6b sends water from a bathtub (not shown) toward the reheating heat exchanger 12. A bathtub circulation pipe 21 connected to the bathtub is connected to the hot water supply mixing unit 15 via a hot water supply pipe 22. A bath solenoid valve 19 is installed in the hot water supply pipe 22.

[0014] The switching valve 7 is configured, for example, by an electromagnetically driven four-way valve having four ports: port A, port B, port C, and port D. The switching valve 7 configures a switching mechanism that switches the flow path of the heated water flowing out from the outlet of the water-refrigerant heat exchanger 2 between the switching valve 8 and a low-temperature water return port 11e at the bottom of the hot water storage tank 11. The switching valve 7 also configures a switching mechanism that returns the hot water flowing out from the high-temperature water outlet 11a at the top of the hot water storage tank 11 to the low-temperature water return port 11e.

[0015] The switching valve 8 is, for example, an electromagnetically driven four-way valve having four ports, E, F, G, and H. The switching valve 8 constitutes a switching mechanism that switches the flow path of water flowing in from port E between a reheating return port 11c located at the middle height of the hot water storage tank 11, a high-temperature water inlet / outlet 11b located at the top of the hot water storage tank 11, and the reheating heat exchanger 12. The switching valve 9 is, for example, an electromagnetically driven three-way valve having three ports, I, J, and K. The switching valve 9 constitutes a switching mechanism that switches between a flow path state in which water flowing out from a water intake port 11f located at the bottom of the hot water storage tank 11 passes through the circulation pump 6a and flows into the water-refrigerant heat exchanger 2, and a flow path state in which water flowing out from the reheating heat exchanger 12 passes through the circulation pump 6a and flows into the water-refrigerant heat exchanger 2.

[0016] Mixing valve 10 has three ports: an L port, an M port, and an N port. Mixing valve 10 mixes or selects between medium-temperature water taken out from a medium-temperature water outlet 11d located at the middle height of hot water storage tank 11 and low-temperature water from a water supply terminal connected to a water source, and discharges the mixed water to hot water supply mixing section 15. Hot water storage tank 11 stores heated water. In addition to the high-temperature water outlet 11a, high-temperature water inlet / outlet 11b, reheating return port 11c, medium-temperature water outlet 11d, low-temperature water return port 11e, and water intake port 11f described above, hot water storage tank 11 also has a water supply port 11g located at the bottom of hot water storage tank 11. Water supply port 11g is connected to the water supply terminal via piping 16p. Low-temperature water supplied from the water supply terminal flows into hot water storage tank 11 through piping 16p.

[0017] The outlet of the water-refrigerant heat exchanger 2 is connected to port A of the switching valve 7 via pipe 16a. Port B of the switching valve 7 is connected to port E of the switching valve 8 via pipe 16b. Port F of the switching valve 8 is connected to the high-temperature water outlet 11a via pipes 16c and 16d. Port F is also connected to the primary-side inlet of the reheating heat exchanger 12 via pipes 16c and 16e. The primary-side outlet of the reheating heat exchanger 12 is connected to port J of the switching valve 9 via pipe 16f. The primary-side outlet of the reheating heat exchanger 12 is also connected to a flow path connecting the medium-temperature water outlet 11d and port L of the mixing valve 10 via pipe 16g. Port I of the switching valve 9 is connected to the water intake 11f via pipe 16h. Port K of the switching valve 9 is connected to the suction port of the circulation pump 6a via pipe 16j. The discharge port of the circulation pump 6a is connected to the inlet of the water-refrigerant heat exchanger 2 via a pipe 16k. The discharge port of the circulation pump 6a is also connected to a C port of the switching valve 7 via a pipe 16l. The D port of the switching valve 7 is connected to the low-temperature water return port 11e via a pipe 16m. The H port of the switching valve 8 is connected to the high-temperature water inlet / outlet 11b via a pipe 16n and a pipe 16q. The G port of the switching valve 8 is connected to the reheating return port 11c via a pipe 16o.

[0018] The circulation pump 6a, the hot water storage tank 11, the pipes 16a, 16b, 16h, 16j, 16k, 16n, and 16q, and the switching valves 7, 8, and 9 constitute a hot water storage circuit 201 that stores heated water flowing out from the water-refrigerant heat exchanger 2 in the hot water storage tank 11.

[0019] The circulation pump 6a, the reheating heat exchanger 12, the pipes 16b, 16d, 16e, 16f, 16j, 16l, and 16o, and the switching valves 7, 8, and 9 constitute a reheating circuit 202 that heats the water to be heated on the load side using the reheating heat exchanger 12.

[0020] The circulation pump 6a does not necessarily have to be installed in the hot water storage unit 200, but may be mounted on the heat source unit 100 side. In addition, the high-temperature water inlet / outlet 11b, the medium-temperature water outlet 11d, the piping 16q, the mixing valve 10, and the hot water mixing section 15 form a hot water supply circuit 203 that extracts hot water from the hot water storage tank 11 and supplies it to a bathtub or a hot water supply end.

[0021] In this embodiment, the value of the heating capacity and the value of the boiling temperature by the refrigerant circuit 101 of the heat source machine 100 can be changed. In the following description, the heating capacity by the refrigerant circuit 101 of the heat source machine 100 may be simply referred to as "heating capacity." The heating capacity corresponds to the amount of heat that the heat source machine 100 provides to water per hour. The unit of heating capacity is, for example, kW (kilowatts). The compressor 1 is driven by a drive device (not shown) equipped with, for example, an inverter-controlled DC brushless motor. In this case, by adjusting the rotation speed of the compressor 1 with the drive device, it is possible to change the pressure and temperature of the refrigerant discharged from the compressor 1 and change the value of the heating capacity.

[0022] Next, the control system of the hot water storage type water heater will be described. In the following description, the temperature of the heated water flowing out of the water-refrigerant heat exchanger 2 will be referred to as the "heating temperature." The heat source device 100 is equipped with an inlet water temperature sensor 13a that detects the temperature of the water flowing into the water-refrigerant heat exchanger 2 and a heating temperature sensor 13b that detects the heating temperature. The heating temperature sensor 13b is disposed near the outlet of the water-refrigerant heat exchanger 2. The hot water storage unit 200 is equipped with multiple hot water temperature sensors 13g, 13h, 13i, and 13j. The hot water temperature sensors 13g, 13h, 13i, and 13j are installed in the hot water storage tank 11 at different heights and detect the water temperature in the hot water storage tank 11 at their respective installation locations. The hot water temperature sensors 13g, 13h, 13i, and 13j can detect the amount of hot water and heat stored in the hot water storage tank 11.

[0023] The hot water storage type water heater of this embodiment includes a heat source machine control device 14 mounted on the heat source machine 100, and a water heater control device 50 mounted on the hot water storage unit 200. The heat source machine control device 14 and the water heater control device 50 each include a microcomputer or the like having a memory and a processor. The heat source machine control device 14 and the water heater control device 50 are connected to each other so that they can communicate bidirectionally. In this embodiment, the heat source machine control device 14 and the water heater control device 50 work together to control the operation of the hot water storage type water heater. The heat source machine control device 14 and the water heater control device 50 correspond to control means for controlling hot water storage operation in which hot water heated by the heat source machine 100, i.e., heated water, flows into the hot water storage tank 11.

[0024] In the present disclosure, the heat source machine control device 14, the water heater control device 50, and the remote control 51 may work together to control the operation of the storage type water heater. In the following description, any processing described as being performed by the water heater control device 50 may be performed solely by the heat source machine control device 14, solely by the water heater control device 50, solely by the remote control 51, or may be performed in cooperation with two or more of the heat source machine control device 14, the water heater control device 50, and the remote control 51. Furthermore, the control means for the storage type water heater in the present disclosure is not limited to a configuration in which multiple control devices work together as in the present embodiment, but may be configured by a single control device.

[0025] The water heater control device 50 and the remote control 51 can communicate bidirectionally via wired or wireless communication. The remote control 51 is an example of a user interface. The remote control 51 has a display unit 51a that displays information and an operation unit 51b that is operated by a user. The remote control 51 may have a touch screen that functions as both the display unit 51a and the operation unit 51b. A person, such as a user, can remotely control the hot water storage type water heater and perform various settings by operating the remote control 51. The display unit 51a functions as a notification means that notifies a person, such as a user. In this embodiment, the remote control 51 has the display unit 51a as a notification means. However, as a variation, the remote control 51 may also have other notification means, such as a voice guidance device. The remote control 51 may be installed on a wall, for example, in the kitchen, living room, or bathroom. Multiple remote controls 51 may be capable of communicating with the water heater control device 50. In addition to or instead of the remote control 51, a mobile terminal such as a smartphone, a smart speaker, a television, or other device may be configured to be used as a user interface. The water heater control device 50 and the remote control 51 or other user interfaces may be capable of communicating via the Internet or a local area network. In the following description, operations using the remote control 51 may be substituted for operations using a user interface other than the remote control 51.

[0026] The water heater control device 50 receives inputs such as outputs from various sensors equipped in the hot water storage type water heater and information on user operations on the remote control 51. Based on this input information, the water heater control device 50 controls the operation of the heat source device 100 and the hot water storage unit 200. For example, the water heater control device 50 controls the operating states of the compressor 1, the circulation pump 6a, and the reheating pump 6b, the opening degree of the expansion valve 3, and the flow direction or switching position of the switching valves 7, 8, 9, and the mixing valve 10. The water heater control device 50 also performs hot water storage operation, reheating operation, hot water filling operation, etc. During hot water storage operation, the water heater control device 50 controls the boiling temperature and the heating capacity of the refrigerant circuit 101.

[0027] The water heater control device 50 in this embodiment includes a hot water supply heat quantity calculation means 52 that calculates the amount of heat used to supply hot water (hereinafter referred to as "hot water supply usage heat quantity"). The hot water supply heat quantity calculation means 52 calculates the hot water supply usage heat quantity based on the water supply temperature detected by the water supply temperature sensor 13k, the hot water supply temperature detected by the hot water supply temperature sensor 13l, the hot water temperature detected by the bath hot water supply temperature sensor 13m, the hot water supply flow rate detected by the hot water supply flow rate sensor 17a, and the hot water supply flow rate detected by the bath hot water supply flow rate sensor 17b. The water supply temperature detected by the water supply temperature sensor 13k is the temperature of low-temperature water supplied from the water source to the water supply end. The hot water temperature detected by the hot water supply temperature sensor 13l is the temperature of hot water supplied from the hot water supply mixing unit 15 to hot water supply ends other than the bathtub. The hot water temperature detected by the bath hot water temperature sensor 13m is the temperature of hot water supplied from the hot water supply mixing unit 15 to the bathtub. The hot water flow rate detected by the hot water flow rate sensor 17a is the flow rate of hot water supplied from the hot water supply mixing unit 15 to the hot water supply end. The hot water flow rate detected by the bath hot water flow rate sensor 17b is the flow rate of hot water supplied from the hot water supply mixing unit 15 to the bathtub.

[0028] The water heater control device 50 has the function of learning the amount of heat used for hot water supply by storing data on the amount of heat used for hot water supply calculated by the hot water supply heat amount calculation means 52 for a predetermined period in the past. In the present disclosure, the predetermined period in the past may be, for example, the past two weeks. For example, the water heater control device 50 learns the amount of heat used for hot water supply by statistically processing the amount of heat used for hot water supply for the predetermined period in the past. The water heater control device 50 can also learn the amount of heat used for hot water supply by hour in a day. The amount of heat used for hot water supply for the predetermined period in the past corresponds to the past hot water supply load.

[0029] Next, the operation of the hot water storage operation of the hot water storage type water heater will be described. In the hot water storage operation, the refrigerant circuit 101 and the hot water storage circuit 201 are operated, so that low-temperature water flowing out from the water intake port 11f of the hot water storage tank 11 is heated by the refrigerant circuit 101, and the high-temperature heated water flowing out from the outlet of the water-refrigerant heat exchanger 2 flows into the hot water storage tank 11 from the high-temperature water inlet / outlet 11b.

[0030] The hot water storage operation will be further explained below. In the refrigerant circuit 101, the high-temperature, high-pressure gas refrigerant discharged from the compressor 1 drops in temperature while releasing heat to the water flowing through the water-refrigerant heat exchanger 2. At this time, if the high-pressure side refrigerant pressure is equal to or lower than the critical pressure, the refrigerant releases heat while liquefying. The high-pressure, low-temperature refrigerant flowing out of the water-refrigerant heat exchanger 2 is reduced in pressure to a low-pressure gas-liquid two-phase state by passing through the expansion valve 3. This refrigerant then absorbs heat from the outside air while flowing through the air heat exchanger 4, thereby evaporating and gasifying. The low-pressure refrigerant flowing out of the air heat exchanger 4 is drawn into the compressor 1 and circulated, forming a refrigeration cycle, i.e., a heat pump cycle.

[0031] Furthermore, pipes 16a and 16b are interconnected by selector valve 7, pipes 16b and 16n are interconnected by selector valve 8, and pipes 16h and 16j are interconnected by selector valve 9. This forms hot water storage circuit 201. When circulation pump 6a is operated, water in hot water storage tank 11 is introduced from water intake port 11f through pipes 16h, 16j, and 16k into water-refrigerant heat exchanger 2. This water is heated by gas refrigerant in water-refrigerant heat exchanger 2 and flows out of water-refrigerant heat exchanger 2 as heated water. This heated water passes through pipes 16a, 16b, 16n, and 16q and flows into hot water storage tank 11 from high-temperature water inlet / outlet 11b. When hot water storage operation is performed in this manner, hot water is stored in hot water storage tank 11 while maintaining a temperature distribution in which the upper part contains high-temperature water and the lower part contains low-temperature water.

[0032] Next, the hot water temperature control and heating capacity control of the refrigerant circuit 101 performed by the water heater control device 50 during hot water storage operation will be described. Temperature control involves feedback control of the rotation speed of the circulation pump 6a so that the boiling temperature detected by the boiling temperature sensor 13b is equal to a predetermined target boiling temperature. This feedback control is performed periodically, for example, at regular time intervals. During hot water storage operation, hot water storage is performed with the target boiling temperature set to a predetermined target hot water storage temperature. That is, the target boiling temperature is equal to the target hot water storage temperature. For example, the water heater control device 50 sets the target hot water storage temperature, i.e., the target boiling temperature, in relation to the capacity of the hot water storage tank 11 so that the target hot water storage amount can be stored in the hot water storage tank 11. The target hot water storage amount corresponds to a target value for the amount of heat to be stored in the hot water storage tank 11. The water heater control device 50 may set the target hot water storage amount based on, for example, the operation details of the remote control 51, or may calculate the target hot water storage amount based on learned information about past hot water supply heat usage.

[0033] The water heater control device 50 may set the target hot water storage temperature to 65° C. or higher, or may set the target hot water storage temperature to less than 65° C. (for example, 55° C.) Setting the target hot water storage temperature to a lower value improves energy efficiency.

[0034] The hot water storage type water heater of this embodiment can perform a bath filling operation to fill the bathtub with hot water. During the bath filling operation, the bath solenoid valve 19 is opened, and the operation of the hot water supply mixer 15 is controlled so that the hot water temperature detected by the bath hot water temperature sensor 13m becomes equal to the target value for the bath filling temperature.

[0035] The hot water storage type water heater of this embodiment is capable of switching between a bath filling operation in which the hot water flowing out of the hot water storage tank 11 is mixed with the hot water flowing out of the heat source unit 100 to fill the bathtub, and a bath filling operation in which only the hot water flowing out of the hot water storage tank 11 is supplied to the bathtub without using the heat source unit 100.

[0036] 1 shows the path of water flow during hot water filling operation in conjunction with the heat source unit 100. During hot water filling operation in conjunction with the heat source unit 100, water flowing out from water intake 11f at the bottom of hot water storage tank 11 flows into hot water supply mixer 15 through circulation pump 6a, water-refrigerant heat exchanger 2, switching valve 7, switching valve 8, and piping 16n. Also, high-temperature water flowing out from high-temperature water inlet / outlet 11b at the top of hot water storage tank 11 flows into hot water supply mixer 15 through piping 16q. In this way, the hot water supplied from heat source unit 100 and the hot water supplied from hot water storage tank 11 are mixed in hot water supply mixer 15 and supplied to the bathtub.

[0037] During the bath filling operation, the water heater control device 50 detects the amount of hot water supplied to the bathtub using the bath hot water supply flow rate sensor 17b, and when the amount of hot water supplied becomes equal to the target value, it closes the bath solenoid valve 19 and ends the bath filling operation.

[0038] The water heater control device 50 can predict the predicted amount of hot water to be used after the bath filling operation based on the amount of hot water heat used for a predetermined past period learned using the hot water heat amount calculation means 52. The water heater control device 50 can also calculate the amount of hot water stored in the hot water storage tank 11 that can be used for the bath filling operation by subtracting the predicted amount of hot water to be used after the bath filling operation from the current amount of hot water stored in the hot water storage tank 11. If the amount of hot water stored in the hot water storage tank 11 that can be used for the bath filling operation is smaller than the amount of hot water required to fill the bathtub, the water heater control device 50 can calculate the heating capacity of the heat source device 100 during the bath filling operation using the amount of hot water stored in the hot water storage tank 11 that can be used for the bath filling operation, the temperature in the hot water storage tank 11, the amount of hot water filled, the temperature of the hot water storage tank 11, the temperature of the water supply, and the time required for the bath filling operation. At this time, the water heater control device 50 calculates the heating capacity of the heat source device 100 during the bath filling operation so that the shortage of hot water stored in the hot water storage tank 11 that can be used for the bath filling operation compared to the amount of hot water needed to fill the bathtub can be compensated for with hot water supplied from the heat source device 100. This ensures that the amount of heat stored in the hot water storage tank 11 after the bath filling operation is maintained, making it possible to reliably prevent hot water shortages. In particular, even when the stored hot water temperature is lowered compared to conventional methods and the surplus amount of heat stored is reduced, the bath filling operation can be performed while maintaining the amount of heat stored after the bath filling operation.

[0039] Specifically, the water heater control device 50 calculates the heating capacity of the heat source device 100 during the water filling operation according to the following formula. The amount of heat required to fill a bathtub can be calculated using the following formula: Heat capacity of water filling [kJ] = specific heat of water [kJ / kgK] x (water filling temperature [℃] - water supply temperature [℃]) x water volume [L] x water density [kg / m 3 ]

[0040] Heat capacity of the tank available for filling the bath [kJ] = specific heat of water [kJ / kgK] x (temperature of hot water stored in the tank [℃] - temperature of water supplied [℃]) x available amount of hot water in the tank [L] x density of water [kg / m 3 ]

[0041] Heating capacity of heat source unit 100 [kW] = (heat amount used for filling the bath - heat amount available for filling the bath) / time required for filling the bath [s]

[0042] FIG. 2 is a flowchart showing the control operation in the first embodiment. In step S1 of FIG. 2, the water heater control device 50 predicts the predicted amount of hot water to be used after the hot water filling operation. Next, in step S2, the water heater control device 50 calculates the amount of hot water stored in the hot water storage tank 11 that can be used for the hot water filling operation by subtracting the predicted amount of hot water to be used after the hot water filling operation from the current amount of hot water stored in the hot water storage tank 11. Next, in step S3, the water heater control device 50 determines whether the amount of hot water stored in the hot water storage tank 11 that can be used for the hot water filling operation is smaller than the amount of hot water required to fill the bathtub. If the answer is Yes in step S3, in step S4, the water heater control device 50 calculates the heating capacity of the heat source device 100 during the hot water filling operation using the amount of hot water stored in the hot water storage tank 11 that can be used for the hot water filling operation, the temperature in the hot water storage tank 11, the amount of hot water filled, the temperature of the hot water storage tank 11, the temperature of the water supply, and the time required for the hot water filling operation. Then, in step S5, the water heater control device 50 performs a water filling operation in conjunction with the heat source device 100. At this time, the water heater control device 50 controls the heat source device 100 so that the heating capacity of the heat source device 100 becomes the value calculated in step S4.

[0043] In contrast, if the answer is No in step S3, the water heater can fill the tub using only the amount of hot water stored in the hot water storage tank 11, so the water heater control device 50 performs the water heater filling operation using only the hot water in the hot water storage tank 11 without using the heat source unit 100.

[0044] The hot water storage type water heater of this embodiment may store hot water in hot water storage tank 11 at a storage temperature determined based on the capacity of hot water storage tank 11 and the history of the amount of hot water used per day over a predetermined period of time in the past. This can reliably prevent hot water from running out.

[0045] Furthermore, the hot water storage type water heater of this embodiment may be configured so that the temperature of the hot water stored in hot water storage tank 11 is a temperature that allows hot water storage tank 11 to supply the entire amount of hot water used in one day, which is predicted from the history of the amount of hot water used in one day. This makes it possible to more reliably prevent hot water shortages from occurring.

[0046] The maximum value of the heating capacity of the heat source device 100 during the hot water filling operation may be greater than the maximum value of the heating capacity of the heat source device 100 during the hot water storage operation in which hot water is stored in the hot water storage tank 11. This makes it possible to more reliably maintain the amount of heat stored in the hot water storage tank 11 after the hot water filling operation.

[0047] The heating temperature, i.e., the boiling temperature, of the heat source machine 100 during the water filling operation may be equal to or lower than the temperature of the hot water stored in the hot water storage tank 11. This makes it possible to increase the COP (coefficient of performance) of the heat source machine 100 during the water filling operation.

[0048] If the heating capacity value of the heat source unit 100 during the water filling operation calculated in step S4 is greater than the maximum heating capacity of the heat source unit 100, the water heater control device 50 may operate the heat source unit 100 at the maximum heating capacity during the water filling operation in step S5, and continue operating the heat source unit 100 even after the water filling operation is completed until the amount of hot water stored in the hot water storage tank 11 reaches the predicted amount of hot water to be used after the water filling operation. This makes it possible to reliably prevent hot water from running out after the water filling operation.

[0049] FIG. 3 is a diagram showing an example of a configuration for realizing the functions of the heat source machine control device 14, the water heater control device 50, or the remote control 51 in the first embodiment. Each function of the heat source machine control device 14, the water heater control device 50, or the remote control 51 is realized by, for example, a processing circuit. The processing circuit may be dedicated hardware 600. The processing circuit may include a processor 601 and a memory 602. A part of the processing circuit may be formed as dedicated hardware 600, and the processing circuit may further include a processor 601 and a memory 602. In the example shown in FIG. 3, a part of the processing circuit is formed as dedicated hardware 600. Furthermore, in the example shown in FIG. 3, the processing circuit further includes a processor 601 and a memory 602 in addition to the dedicated hardware 600.

[0050] The processing circuitry of which at least one portion is dedicated hardware 600 may be, for example, a single circuit, a multiple circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof.

[0051] When the processing circuit has at least one processor 601 and at least one memory 602, the functions of each part of the heat source machine control device 14, the water heater control device 50 or the remote control 51 are realized by software, firmware, or a combination of software and firmware.

[0052] The software and firmware are written as programs and stored in memory 602. The programs may be recorded on a computer-readable recording medium. The processor 601 realizes the functions of each unit by reading and executing the programs stored in memory 602. The processor 601 is also called a CPU (Central Processing Unit), central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, or DSP. The memory 602 may be, for example, a non-volatile or volatile semiconductor memory such as RAM, ROM, flash memory, EPROM, or EEPROM, or a magnetic disk, flexible disk, optical disk, compact disk, minidisk, DVD, etc.

[0053] In this way, the processing circuit can realize the functions of the heat source machine control device 14, the water heater control device 50, or the remote control 51 by using hardware, software, firmware, or a combination of these. Note that each function of the heat source machine control device 14, the water heater control device 50, or the remote control 51 may be realized by multiple devices working together, or may be realized by a single device. Furthermore, at least a portion of each function of the heat source machine control device 14, the water heater control device 50, or the remote control 51 may be implemented in a server or the like on an external network.

[0054] Various aspects of the present disclosure are summarized below as appendices.

[0055] (Appendix 1) A heat source machine that heats water; a hot water storage tank that stores hot water heated by the heat source device; a control means for controlling the operation of the heat source machine; Equipped with It is possible to perform a bath filling operation in which the hot water flowing out from the hot water storage tank and the hot water flowing out from the heat source machine are mixed to fill the bathtub, The control means predicts the expected amount of hot water to be used after the hot water filling operation, calculates the amount of hot water stored in the hot water storage tank that can be used for the hot water filling operation from the current amount of hot water stored in the hot water storage tank and the predicted amount of hot water, and if the amount of hot water stored in the hot water storage tank that can be used for the hot water filling operation is smaller than the amount of hot water required to fill the bathtub, the heating capacity of the heat source unit during the hot water filling operation can be calculated using the amount of hot water stored in the hot water storage tank that can be used for the hot water filling operation, the temperature in the hot water storage tank, the amount of hot water filled, the hot water filling temperature, the water supply temperature, and the hot water filling time. (Appendix 2) A hot water storage type water heater as described in Appendix 1, in which hot water is stored in the hot water storage tank at a storage temperature determined based on the capacity of the hot water storage tank and the history of the amount of hot water used per day over a predetermined period of time. (Appendix 3) A hot water storage type water heater as described in Appendix 2, wherein the hot water storage temperature is a temperature at which the hot water storage tank can supply the entire amount of hot water used in a day, as predicted from the history of hot water usage in a day. (Appendix 4) A hot water storage type water heater described in any one of Appendix 1 to Appendix 3, wherein the maximum value of the heating capacity of the heat source unit during the hot water filling operation is greater than the maximum value of the heating capacity of the heat source unit during the hot water storage operation in which hot water is stored in the hot water storage tank. (Appendix 5) 5. The hot water storage type water heater according to claim 1, wherein the heating temperature of the heat source unit during the hot water filling operation is equal to or lower than the temperature of the hot water stored in the hot water storage tank. (Appendix 6) A hot water storage type water heater described in any one of Appendix 1 to Appendix 5, wherein if the calculated value of the heating capacity of the heat source unit during the hot water filling operation is greater than the maximum heating capacity of the heat source unit, the control means operates the heat source unit at the maximum heating capacity during the hot water filling operation, and continues to operate the heat source unit even after the hot water filling operation ends until the amount of hot water stored in the hot water storage tank reaches the predicted amount of hot water to be used after the hot water filling operation. [Explanation of symbols]

[0056] 1 compressor, 2 water-refrigerant heat exchanger, 3 expansion valve, 4 air heat exchanger, 5 fan, 6a circulation pump, 6b reheating pump, 7 switching valve, 8 switching valve, 9 switching valve, 10 mixing valve, 11 hot water storage tank, 11a high temperature water outlet, 11b high temperature water inlet / outlet, 11c reheating return port, 11d medium temperature water outlet, 11e low temperature water return port, 11f water intake port, 11g water supply port, 12 reheating heat exchanger, 13a inlet water temperature sensor, 13b temperature sensor, 13g, 13h, 13i, 13j hot water storage temperature sensor, 13k water supply temperature sensor, 13l hot water supply temperature sensor, 13m bath hot water supply temperature sensor, 14 heat source machine control device, 15 Hot water mixing section, 16a pipe, 16b pipe, 16c pipe, 16d pipe, 16e pipe, 16f pipe, 16g pipe, 16h pipe, 16j pipe, 16k pipe, 16l pipe, 16m pipe, 16n pipe, 16o pipe, 16p pipe, 16q pipe, 17a hot water supply flow rate sensor, 17b bath hot water supply flow rate sensor, 19 bath solenoid valve, 21 bathtub circulation pipe, 22 hot water supply pipe, 50 hot water heater control device, 51 remote control, 51a display unit, 51b operation unit, 52 hot water supply heat amount calculation means, 100 heat source machine, 101 refrigerant circuit, 200 hot water storage unit, 201 hot water storage circuit, 202 Reheating circuit, 203 hot water circuit, 600 dedicated hardware, 601 processor, 602 memory

Claims

1. A heat source machine that heats water; a hot water storage tank that stores hot water heated by the heat source device; a control means for controlling the operation of the heat source machine; Equipped with It is possible to perform a bath filling operation in which the hot water flowing out of the hot water storage tank and the hot water flowing out of the heat source machine are mixed to fill the bathtub, The control means predicts the expected amount of hot water to be used after the hot water filling operation, calculates the amount of hot water stored in the hot water storage tank that can be used for the hot water filling operation from the current amount of hot water stored in the hot water storage tank and the predicted amount of hot water, and if the amount of hot water stored in the hot water storage tank that can be used for the hot water filling operation is smaller than the amount of hot water required to fill the bathtub, the heating capacity of the heat source unit during the hot water filling operation can be calculated using the amount of hot water stored in the hot water storage tank that can be used for the hot water filling operation, the temperature in the hot water storage tank, the amount of hot water filled, the hot water filling temperature, the water supply temperature, and the hot water filling time.

2. 2. The hot water storage type water heater according to claim 1, wherein hot water is stored in the hot water storage tank at a temperature determined based on the capacity of the hot water storage tank and a history of the amount of hot water used per day over a predetermined period of time.

3. 3. The hot water storage type water heater according to claim 2, wherein the hot water storage temperature is set to a temperature at which the hot water storage tank can supply the entire amount of hot water to be used in one day, which is predicted from a history of the amount of hot water used in one day.

4. A hot water storage type water heater described in any one of claims 1 to 3, wherein the maximum value of the heating capacity of the heat source unit during the hot water filling operation is greater than the maximum value of the heating capacity of the heat source unit during the hot water storage operation in which hot water is stored in the hot water storage tank.

5. The hot water storage type water heater according to any one of claims 1 to 3, wherein a heating temperature in the heat source unit during the hot water filling operation is equal to or lower than a temperature of hot water stored in the hot water storage tank.

6. A hot water storage type water heater described in any one of claims 1 to 3, wherein if the calculated value of the heating capacity of the heat source unit during the hot water filling operation is greater than the maximum heating capacity of the heat source unit, the control means operates the heat source unit at the maximum heating capacity during the hot water filling operation, and continues to operate the heat source unit even after the hot water filling operation has ended until the amount of hot water stored in the hot water storage tank reaches the predicted amount of hot water to be used after the hot water filling operation.

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