Water heater

Abstract

To provide a technology to stably raising the temperature of water in a hot water storage tank by a heat pump in a suppression mode for setting an upper limit of consumption power of the heat pump.SOLUTION: A controller can execute a boiling operation for heating water in a hot water storage tank to a predetermined boiling target temperature by a heat pump, and can set a suppression mode for setting an upper limit of consumption power of the heat pump. The controller may be configured to set an upper limit of consumption power of the heat pump according to consumption power of elements other than the heat pump in a water heater in the suppression mode, and cause the heat pump to be operated so that the consumption power of the heat pump is less than the set upper limit. When setting the suppression mode, the controller may set the upper limit of the boiling target temperature in the boiling operation lower as the upper limit to be set of the consumption power of the heat pump is lower.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The technology disclosed in this specification relates to a water heater. [Background technology]

[0002] The water heater disclosed in Patent Document 1 includes a heat pump that consumes electricity to heat water, and a hot water storage tank that stores the water heated by the heat pump. The water heater in Patent Document 1 can perform normal operation and power suppression operation in which the water heater operates at or below suppressed power that is lower than the maximum power consumption during normal operation. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-096583 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the power saving operation of Patent Document 1, the power consumption of the heat pump is suppressed, and therefore the heating capacity of the heat pump is suppressed. At that time, the heating capacity required to heat the water in the hot water storage tank to the target temperature may not be achieved by the heat pump, making it difficult to heat the water stably. This specification provides a technology that allows the temperature of the water in the hot water storage tank to be stably heated by the heat pump in a suppression mode that sets an upper limit on the power consumption of the heat pump. [Means for solving the problem]

[0005] In a first aspect of the present technology, a water heater may include a hot water storage tank, a heat pump that heats water in the hot water storage tank, and a controller. The controller may be capable of executing a boiling operation in which the water in the hot water storage tank is heated to a predetermined boiling target temperature by the heat pump, and may be capable of setting a suppression mode in which an upper limit value of power consumption of the heat pump is set. In the suppression mode, the controller may be configured to set an upper limit value of power consumption of the heat pump according to power consumption of elements in the water heater other than the heat pump, and to operate the heat pump so that the power consumption of the heat pump is less than the set upper limit value. When setting the suppression mode, the controller may set the upper limit value of the boiling target temperature in the boiling operation lower as the upper limit value of power consumption of the heat pump to be set is lower.

[0006] In the suppression mode, the power consumption of the heat pump is suppressed, and therefore the heating capacity of the heat pump is suppressed. However, according to the above configuration, when the suppression mode is set, the lower the upper limit of the power consumption of the heat pump is set, the lower the upper limit of the boiling target temperature in the boiling operation is, so that the heating capacity required by the heat pump can be reduced and the water in the hot water storage tank can be stably heated to the boiling target temperature by the heat pump.

[0007] In a second aspect, in the first aspect, the water heater may further include an outside air temperature sensor that detects an outside air temperature. When setting the suppression mode, the controller may set the upper limit of the boiling target temperature in the boiling operation lower as the outside air temperature detected by the outside air temperature sensor becomes lower.

[0008] When the outdoor air temperature is low, it is difficult to absorb heat from the outdoor air, so the heating capacity of the heat pump is suppressed. However, with the above configuration, when the suppression mode is set, the lower the outdoor air temperature detected by the outdoor air temperature sensor, the lower the upper limit of the boiling target temperature in the boiling operation, so that the heating capacity required by the heat pump can be reduced and the water in the hot water storage tank can be stably heated to the boiling target temperature by the heat pump.

[0009] In a third aspect, in the first or second aspect, the water heater may further include an auxiliary heat source unit capable of heating water discharged from the hot water storage tank and supplied to a hot water supply location.

[0010] According to this configuration, even if the target boiling temperature in the boiling operation is set low, warm water can be supplied to the hot water supply location by heating water with the auxiliary heat source unit. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a storage type water heater according to an embodiment of the present invention. [Diagram 2] FIG. 13 is a diagram showing a target boiling temperature upper limit table of an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] (Storage type water heater 104) As shown in FIG. 1, the storage type water heater 104 includes an HP (heat pump) unit 4, a tank unit 6, and a burner unit 8.

[0013] (HP unit 4) The HP unit 4 is a heat source that uses electric power to absorb heat from outside air and heat water. The HP unit 4 includes an HP heat source 17 that includes a compressor 10, a condenser 12, an expansion valve 14, and an evaporator 16. The HP unit 4 absorbs heat from outside air and heats water by circulating a refrigerant (e.g., a fluorocarbon-based refrigerant) through the compressor 10, the condenser 12, the expansion valve 14, and the evaporator 16 in that order. The compressor 10 pressurizes the refrigerant to make it high temperature and high pressure. The condenser 12 cools the refrigerant by heat exchange with water. An HP forward path 19 and an HP return path 21 are connected to both ends of the water flow path of the condenser 12, respectively. The expansion valve 14 depressurizes the refrigerant to make it low temperature and low pressure. The evaporator 16 heats the refrigerant by heat exchange with outside air. The HP unit 4 further includes a circulation pump 18 that circulates water through the condenser 12, a feed thermistor 20 that detects the temperature of the water flowing into the condenser 12, a return thermistor 22 that detects the temperature of the water flowing out of the condenser 12, an outdoor air temperature thermistor 23 (an example of an outdoor air temperature sensor) that detects the outdoor air temperature, and an HP controller 24 that controls the operation of each component of the HP unit 4.

[0014] (Tank Unit 6) The tank unit 6 includes a hot water storage tank (hereinafter referred to as "tank") 30, a mixing valve 32, and a bypass control valve 34. The tank 30 is a sealed container that is covered with a heat insulating material on the outside and stores water inside. The capacity of the tank 30 in this embodiment is, for example, 100 liters. When the circulation pump 18 of the HP unit 4 is driven, the water at the bottom of the tank 30 is sent to the condenser 12 via the tank forward path 31 and the HP forward path 19. The water heated in the condenser 12 and heated to a high temperature is returned from the top of the tank 30 to the inside of the tank 30 via the HP return path 21 and the tank return path 33. When the water heated by the HP unit 4 flows into the tank 30, a temperature stratification is formed inside the tank 30, in which a layer of high temperature water is piled up on a layer of low temperature water. The tank 30 is equipped with an upper thermistor 36 that detects the temperature of the upper water, an intermediate thermistor 37 that detects the temperature of the intermediate water, and a lower thermistor 38 that detects the temperature of the lower water.

[0015] Tap water is supplied to the tank unit 6 from, for example, a waterworks through a water supply path 40. A pressure reducing valve 42 for reducing the water supply pressure and a water inlet thermistor 44 for detecting the water supply temperature are attached to the water supply path 40. The water supply path 40 branches into a tank water supply path 46 that communicates with the bottom of the tank 30 and a tank bypass path 48 that communicates with the mixing valve 32. Check valves 50 and 52 are attached to the tank water supply path 46 and the tank bypass path 48, respectively. A water-side water volume sensor 54 for detecting the flow rate of tap water flowing into the mixing valve 32 is attached to the tank bypass path 48. The top of the tank 30 and the mixing valve 32 are connected through a tank hot water outlet path 56. A check valve 58 and a hot water volume sensor 60 for detecting the flow rate of water from the tank 30 that flows into the mixing valve 32 are attached to the tank hot water outlet path 56.

[0016] The mixing valve 32 mixes tap water flowing in from the tank bypass path 48 and water from the tank 30 flowing in from the tank hot water outlet path 56, and sends the mixed water to a first hot water supply path 62. The mixing valve 32 drives a valve body by a stepping motor (not shown) and adjusts the opening degree on the tank bypass path 48 side (opening degree on the water side) and the opening degree on the tank outlet path 56 side (opening degree on the hot water side). A mixing thermistor 64 that detects the temperature of the water sent out from the mixing valve 32 is attached to the first hot water supply path 62.

[0017] Hot water is supplied from the tank unit 6 to hot water supply locations such as a kitchen, shower, and faucet via a second hot water supply path 66. A hot water supply outlet thermistor 68 for detecting the temperature of water supplied to the hot water supply location, and a check valve 70 are attached to the second hot water supply path 66. The first hot water supply path 62 and the second hot water supply path 66 are connected by a hot water supply bypass path 72. A bypass control valve 34 is attached to the hot water supply bypass path 72. The tank unit 6 further includes a tank controller 74 for controlling the operation of each component of the tank unit 6.

[0018] (Burner unit 8) The burner unit 8 includes a burner 80, a heat exchanger 82, a bypass servo 84, a water volume servo 86, and a water filling valve 88. The burner 80 is an auxiliary heat source device that heats water flowing through the heat exchanger 82 by burning fuel gas (e.g., city gas). Fuel gas is supplied to the burner 80 through a gas supply pipe (not shown). Water flows into the heat exchanger 82 from the first hot water supply path 62 of the tank unit 6 through a burner forward path 90. The water that has passed through the heat exchanger 82 flows out to the second hot water supply path 66 of the tank unit 6 through a burner return path 92. The burner forward path 90 is equipped with a water volume servo 86 that adjusts the flow rate of water flowing through the burner forward path 90 and a water volume sensor 91 that detects the flow rate of water flowing through the burner forward path 90. The burner forward path 90 and the burner return path 92 are connected through a burner bypass path 94. A bypass servo 84 is attached to the connection between the burner outward path 90 and the burner bypass path 94. The bypass servo 84 adjusts the flow rate of water flowing from the burner outward path 90 to the burner bypass path 94. A burner hot water thermistor 96 that detects the temperature of the water flowing out from the heat exchanger 82 is attached to the burner return path 92. A water filling path 98 branches off from the burner return path 92. A water filling valve 88 is attached to the water filling path 98. Water is filled into the bathtub, which is the hot water supply point, from the burner unit 8 via the water filling path 98.

[0019] The burner unit 8 further includes a burner controller 97 and a remote control 99 capable of communicating with the burner controller 97. The burner controller 97 controls the operation of each component of the burner unit 8. The remote control 99 accepts various operational inputs from the user via switches, buttons, etc. The remote control 99 also notifies the user of various information related to the settings and operation of the storage type water heater 104 by display and voice.

[0020] The HP controller 24, the tank controller 74, the burner controller 97, and the remote control 99 each include a control unit such as a CPU, a ROM, and a RAM, and a storage unit such as an EEPROM, and the control unit executes various processes according to the programs stored in the storage unit. The HP controller 24 and the tank controller 74 can communicate with each other. The tank controller 74 and the burner controller 97 can communicate with each other. Therefore, the HP controller 24, the tank controller 74, and the burner controller 97 cooperate to perform control, so that the storage type water heater 104 can perform various operations such as boiling operation and hot water supply operation. Hereinafter, the HP controller 24, the tank controller 74, and the burner controller 97 are collectively referred to simply as controllers.

[0021] (Boiling operation) In the boiling operation, the storage type water heater 104 drives the HP unit 4 to heat the water in the tank 30. When the boiling operation is started, the controller drives the compressor 10 of the HP heat source 17 to circulate the refrigerant through the compressor 10, the condenser 12, the expansion valve 14, and the evaporator 16 in this order, and drives the circulation pump 18 to circulate the water between the tank 30 and the condenser 12. As a result, the water sucked out from the bottom of the tank 30 is heated to a predetermined boiling target temperature in the condenser 12 and returned to the top of the tank 30. When the temperature detected by the forward thermistor 20 reaches the boiling target temperature, the controller determines that all the water in the tank 30 has been replaced with water heated to the boiling target temperature, and ends the boiling operation.

[0022] The boiling operation is performed periodically, for example. Specifically, the controller starts the boiling operation when a predetermined boiling start time arrives. The controller may also start the boiling operation when a user inputs an instruction to start the boiling operation. The boiling operation is performed, for example, when a large amount of hot water flows out of the tank 30 as a result of the bathtub being filled with hot water. Specifically, the controller starts the boiling operation when the flow rate detected by the hot water side water volume sensor 60 is equal to or greater than a predetermined reference flow rate. The boiling operation is performed, for example, when the amount of hot water stored in the tank 30 is low. Specifically, the controller starts the boiling operation when the temperature detected by the upper thermistor 36 is lower than the hot water supply setting temperature. The boiling target temperature in the boiling operation is determined, for example, from the hot water supply setting temperature set by the user.

[0023] (Hot water supply operation) In hot water supply operation, the storage type water heater 104 supplies water at the hot water supply setting temperature to the hot water supply location. The hot water supply setting temperature is a temperature set by the user. When the combined flow rate (also called the hot water supply flow rate) of the flow rate detected by the water side water flow sensor 54 and the flow rate detected by the hot water side water flow sensor 60 reaches or exceeds the minimum operating flow rate, the controller determines that hot water supply to the hot water supply location has started by opening the faucet or filling the bathtub with water. Depending on the temperature detected by the upper thermistor 36, the controller executes the following non-combustion hot water supply operation or combustion hot water supply operation.

[0024] The controller executes non-combustion hot water supply operation when the temperature detected by the upper thermistor 36 is equal to or higher than the hot water supply set temperature. In non-combustion hot water supply operation, the controller prohibits the combustion operation of the burner 80 and adjusts the opening of the mixing valve 32 so that the temperature detected by the mixing thermistor 64 becomes the hot water supply set temperature. As a result, water whose temperature has been adjusted to the hot water supply set temperature is supplied to the hot water supply location.

[0025] Moreover, when the temperature detected by the upper thermistor 36 is lower than the hot water supply set temperature, the controller executes the combustion hot water supply operation. In the combustion hot water supply operation, the controller permits the combustion operation of the burner 80 and adjusts the opening of the mixing valve 32 so that the temperature detected by the mixing thermistor 64 is lower than the hot water supply set temperature by the minimum heating capacity of the burner 80. In this case, the high-temperature water supplied from the upper part of the tank 30 and the low-temperature water supplied from the water supply path 40 are mixed in the mixing valve 32, heated to the hot water supply set temperature by the burner 80, and supplied to the hot water supply location. The controller adjusts the heating capacity of the burner 80 so that the water heated by the burner 80 becomes the hot water supply set temperature. The combustion hot water supply operation also includes a case where the opening of the mixing valve 32 on the tank hot water outlet path 56 side (opening on the hot water side) is fully closed. That is, a case where water is not supplied from the tank 30 and only the water supplied from the water supply path 40 is heated by the burner 80 is also included.

[0026] If the hot water flow rate falls below the minimum operating flow rate while the above-mentioned non-combustion hot water supply operation or combustion hot water supply operation is being performed, the controller determines that hot water supply to the hot water supply point has ended due to the faucet being closed or the bathtub being filled with water, for example, and ends the hot water supply operation.

[0027] (Normal mode, Suppression mode) In the storage type water heater 104 of the embodiment, a normal mode or a suppression mode is set as the mode of power consumption during operation. The normal mode is a mode in which an upper limit value for power consumption of the HP unit 4 is not set. The storage type water heater 104 is capable of performing boiling operation in the normal mode. In boiling operation in the normal mode, the storage type water heater 104 heats the water in the tank 30 in a state in which an upper limit value for power consumption of the HP unit 4 is not set. In the HP unit 4, for example, the compressor 10 and the circulation pump 18 consume power during boiling operation.

[0028] The suppression mode is a mode in which an upper limit value of the power consumption of the HP unit 4 is set. In boiling operation in the suppression mode, the storage type water heater 104 heats the water in the tank 30 with an upper limit value of the power consumption of the HP unit 4 set. The upper limit value of the power consumption of the HP unit 4 in the suppression mode is changeable. For example, the controller changes the setting of the upper limit value of the power consumption of the HP unit 4 in the suppression mode according to the power consumption of the tank unit 6 and the power consumption of the burner unit 8. The controller changes the setting of the upper limit value of the power consumption of the HP unit 4 at a predetermined time interval (for example, 10 second intervals), for example. The controller may change the setting of the upper limit value of the power consumption of the HP unit 4 in the suppression mode, for example, every time the power consumption of the tank unit 6 and / or the power consumption of the burner unit 8 changes.

[0029] The storage type hot water heater 104 can perform boiling operation within a limited range in the suppression mode. When performing boiling operation in the suppression mode, the controller controls the operation of the HP unit 4 so that the power consumption of the HP unit 4 is less than a set upper limit value.

[0030] The controller sets either a normal mode or a suppression mode in controlling the storage type water heater 104. For example, the controller sets the normal mode when the storage type water heater 104 is connected to a storage battery and the amount of electricity stored in the storage battery is equal to or greater than a predetermined reference amount. On the other hand, the controller sets the suppression mode when the amount of electricity stored in the storage battery is less than a predetermined reference amount. When the controller sets the normal mode, for example, the controller generates information indicating that the normal mode is set (for example, a normal mode flag) and stores this in the storage unit of the controller. When the controller sets the suppression mode, for example, the controller generates information indicating that the suppression mode is set (for example, a suppression mode flag) and stores this in the storage unit of the controller.

[0031] In a modified example, the suppression mode may be set regardless of the amount of electricity stored in the storage battery. For example, the controller may set the suppression mode according to the supply and demand situation of electricity at a power company. In addition, the controller may set the suppression mode in the storage type water heater 104 in order to supply electricity to other devices when other devices are connected to the storage battery, for example. In addition, the controller may set the suppression mode in the storage type water heater 104 according to an instruction from a user or the operating status of the storage type water heater 104.

[0032] (Boiling operation in suppression mode) When the suppression mode is set in the storage type hot water heater 104, the controller can change the setting of the upper limit of the boiling target temperature in the boiling operation. The controller sets the upper limit of the boiling target temperature in the boiling operation in the suppression mode according to the upper limit of the power consumption of the HP unit 4 in the suppression mode and the outside air temperature detected by the outside air temperature thermistor 23. When the upper limit of the boiling target temperature is lower than the boiling target temperature in the boiling operation, the controller sets the boiling target temperature to the upper limit of the boiling target temperature. The lower the upper limit of the power consumption of the HP unit 4 in the suppression mode, the lower the controller sets the upper limit of the boiling target temperature in the boiling operation. Also, the lower the outside air temperature detected by the outside air temperature thermistor 23, the lower the controller sets the upper limit of the boiling target temperature in the boiling operation.

[0033] Specifically, the controller sets the upper limit of the boiling target temperature based on a boiling target temperature upper limit table (see FIG. 2) stored in the storage unit. The boiling target temperature upper limit table includes relationship information among the upper limit of the power consumption of the HP unit 4 in the suppression mode, the outside air temperature detected by the outside air temperature thermistor 23, and the upper limit of the boiling target temperature in the boiling operation. In the boiling target temperature upper limit table, the lower the upper limit of the power consumption of the HP unit 4, the lower the upper limit of the boiling target temperature in the boiling operation is set. Also, in the boiling target temperature upper limit table, the lower the lower the outside air temperature detected by the outside air temperature thermistor 23, the lower the upper limit of the boiling target temperature in the boiling operation is set.

[0034] When performing boiling operation in suppression mode, the controller sets the upper limit of the boiling target temperature based on the boiling target temperature upper limit table (see FIG. 2). For example, when the upper limit of the power consumption of the HP unit 4 in suppression mode is 600 VA and the outside air temperature detected by the outside air temperature thermistor 23 is 2°C, the controller sets the upper limit of the boiling target temperature in boiling operation in suppression mode to 60°C. When the upper limit of the boiling target temperature is 60°C, the controller sets the boiling target temperature to 60°C if the command value of the boiling target temperature exceeds 60°C. When the upper limit of the boiling target temperature is 60°C, the controller sets the boiling target temperature to the temperature of the command value (for example, 58°C) if the command value of the boiling target temperature is 60°C or less and exceeds 55°C. Note that the maximum value of the upper limit of the power consumption of the HP unit 4 in the suppression mode of this embodiment is 850 VA. The HP unit 4 of the storage type hot water heater 104 heats the water in the tank 30 to the set boiling target temperature. The controller ends the boiling operation when the temperature detected by the feed thermistor 20 reaches the set boiling target temperature.

[0035] The storage type water heater 104 of the embodiment has been described above. As described above, the storage type water heater 104 can execute a boiling operation in which the water in the tank 30 is heated to a boiling target temperature by the HP unit 4, and can set a suppression mode in which an upper limit value of the power consumption of the HP unit 4 is set. In the suppression mode, the controller sets an upper limit value of the power consumption of the HP unit 4 according to the power consumption of elements (e.g., the tank unit 6 and the burner unit 8) other than the HP unit 4 in the storage type water heater 104, and operates the HP unit 4 so that the power consumption of the HP unit 4 is less than the set upper limit value. When setting the suppression mode, the controller sets a lower upper limit value of the boiling target temperature in the boiling operation as the upper limit value of the power consumption of the HP unit 4 is lower.

[0036] In the suppression mode, the power consumption of the HP unit 4 is suppressed, and therefore the heating capacity of the HP unit 4 is suppressed. However, according to the above configuration, when the suppression mode is set, the lower the upper limit of the power consumption of the HP unit 4, the lower the upper limit of the boiling target temperature in the boiling operation, so that the water in the tank 30 can be stably heated to the boiling target temperature by the HP unit 4.

[0037] Furthermore, when setting the suppression mode, the controller sets the upper limit of the boiling target temperature in the boiling operation lower as the outside air temperature detected by the outside air temperature thermistor 23 becomes lower.

[0038] When the outside air temperature is low, it is difficult to absorb heat from the outside air, and the heating capacity of the HP unit 4 is suppressed. However, according to the above configuration, when the suppression mode is set, the lower the outside air temperature detected by the outside air temperature thermistor 23, the lower the upper limit of the boiling target temperature in the boiling operation, so that the water in the tank 30 can be stably heated to the boiling target temperature by the HP unit 4. Furthermore, by performing the boiling operation even when the outside air temperature is low, freezing of the water can be prevented.

[0039] The storage type water heater 104 is equipped with a burner 80 (auxiliary heat source device) capable of heating water discharged from the tank 30 and supplied to the hot water supply location. With this configuration, even if the boiling target temperature in the boiling operation is set low, warm water can be supplied to the hot water supply location by heating the water with the burner 80.

[0040] (Modification) (1) The storage type water heater 104 may have one or more modes other than the normal mode and the suppression mode. The controller may be capable of performing boiling operation in the normal mode, the suppression mode, and one or more modes other than those.

[0041] (2) Although the above-described auxiliary heat source unit is configured to heat water by burning fuel gas, the present invention is not limited to this configuration. A modified auxiliary heat source unit may be configured to heat water by electrical energy.

[0042] Although each embodiment has been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of these objectives is itself technically useful. [Explanation of symbols]

[0043] 4:HP unit 6: Tank unit 8: Burner unit 17: HP heat source 30: Tank 80: Burner 104: Storage water heater

Claims

1. A hot water tank and A heat pump that heats the water in the hot water storage tank; A water heater comprising: The controller: A boiling operation is performed in which the water in the hot water storage tank is heated to a predetermined boiling target temperature by the heat pump, and a suppression mode is set in which an upper limit value of power consumption of the heat pump is set, In the suppression mode, an upper limit value of the power consumption of the heat pump is set according to the power consumption of elements other than the heat pump in the water heater, and the heat pump is operated so that the power consumption of the heat pump is less than the set upper limit value, The water heater, in which, when the suppression mode is set, the upper limit value of the boiling target temperature in the boiling operation is set lower as the upper limit value of the power consumption of the heat pump to be set is lower.

2. An outside air temperature sensor for detecting an outside air temperature is further provided, The water heater according to claim 1 , wherein when the suppression mode is set, the controller sets the upper limit of the boiling target temperature in the boiling operation lower as the outside air temperature detected by the outside air temperature sensor becomes lower.

3. The water heater according to claim 1 or 2, further comprising an auxiliary heat source unit capable of heating water discharged from the hot water storage tank and supplied to a hot water supply location.

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