JP4674653B1 - Water heater - Google Patents

Abstract

To provide a water heater that realizes a water-saving operation while maintaining usability by changing the flow rate to a predetermined water-saving rate with respect to the use flow rate set by a user.
A hot water supply line for supplying hot water to a hot water supply terminal, a flow rate detecting means for detecting a flow rate of hot water flowing through the hot water supply line, and a flow rate of hot water flowing through the hot water supply line are adjusted. A flow rate adjusting means 44 and a control means 94 are provided, and the flow rate of the hot water flowing through the hot water supply pipe line is a water saving flow rate calculated from a predetermined water saving rate with respect to the initial flow rate detected by the flow rate detecting means 44. In addition, the flow rate of the hot water flowing through the hot water supply pipe 40 is varied by the flow rate adjusting means 44 around the water-saving flow rate.
[Selection] Figure 1

Description

  The present invention relates to a water heater that supplies hot water to a hot water supply terminal.

  Conventionally, this type of water heater has a flow rate limiting means for limiting the maximum flow rate limit value to a predetermined flow rate value lower than the maximum value, so that the user can stop the water faucet by forcibly suppressing the capacity of the water heater. The water can be saved without reducing the flow rate. Moreover, the setting and cancellation | release of a restriction | limiting flow volume are enabled by the user arbitrarily by an operation part (for example, refer patent document 1).

  In addition, because the proper flow rate to be used differs depending on the application, such as when washing dishes in the kitchen and when using a shower in the bathroom, detection means for detecting the presence or absence of a hot water request at each of different hot water outlets In some cases, it is possible to control by changing the limit flow rate according to the hot water destination where the hot water is requested (for example, see Patent Document 2).

JP-A-9-303865 JP-A-11-281146

  However, in the conventional configuration, only the maximum flow rate of the hot water outlet provided with a detecting means for detecting the presence or absence of the hot water request is limited, and when it is used below the limited flow rate, no water saving function is provided. It had the problem of not fulfilling.

  In addition, even if the intended use of the hot water outlet is not uniform or the appropriate flow rate differs depending on the user and you want to use it at a flow rate that is higher than the restricted flow rate, the maximum flow rate is limited by the restricted flow rate, and you are not satisfied with the used flow rate. I had the problem of feeling.

  In addition, since the flow rate is simply lowered, there is a problem that in using a shower or the like, the limited flow rate cannot be set very low because the shower at the limited flow rate is felt weakly and the water-saving effect is not increased. It was.

  In addition, when providing a limited flow rate at each of the hot water outlets, it is necessary to provide hot water detection means at the hot water outlet, and it is necessary to make the system including hot water supply equipment instead of the equipment alone. There was a problem of becoming.

  The present invention solves the above-described conventional problems, and realizes water-saving operation while maintaining usability by changing the flow rate to a predetermined water-saving rate with respect to the use flow rate set by the user. The purpose is to provide a water heater.

  In order to solve the above-described conventional problems, a water heater of the present invention includes a hot water supply pipe for supplying hot water to a hot water supply terminal, a flow rate detection means for detecting a flow rate of hot water flowing through the hot water supply pipe, and the hot water supply pipe. The flow rate adjusting means for adjusting the flow rate of the hot water flowing through the control unit and a control means are provided, and the flow rate of the hot water flowing through the hot water supply pipe is calculated from a predetermined water saving rate with respect to the initial flow rate detected by the flow rate detection means. The flow rate of the hot water flowing through the hot water supply pipe is varied around the water-saving flow rate by the flow rate adjusting means so that the water-saving flow rate is obtained.

  This makes it possible to control the water saving flow rate at a predetermined water saving rate with respect to the flow rate that the user wants to use regardless of the source of water and the purpose of use. By varying the magnitude, water-saving operation can be performed without feeling uncomfortable with the initial flow rate set by the user.

  ADVANTAGE OF THE INVENTION According to this invention, the water heater which implement | achieves water-saving operation can be provided, maintaining usability by changing a flow volume so that it may become a predetermined water-saving rate with respect to the use flow volume set by the user.

The block diagram of the hot water storage type hot water heater in Embodiment 1 of this invention Flow chart of water saving operation in the same form Other water-saving operation flowchart in the same form Other water-saving operation flowchart in the same form The figure which shows the relationship between the flow of water saving operation and the water saving rate Other water-saving operation flowchart in the same form

  A first aspect of the invention is a hot water supply pipe for supplying hot water to a hot water supply terminal, a flow rate detecting means for detecting a flow rate of hot water flowing through the hot water supply pipe, and a flow rate adjusting means for adjusting the flow rate of hot water flowing through the hot water supply pipe. And the control means, and the hot water supply pipe line so that the flow rate of the hot water flowing through the hot water supply pipe line becomes a water saving flow rate calculated from a predetermined water saving rate with respect to the initial flow rate detected by the flow rate detection means The hot water flowing through the hot water heater is characterized by changing the flow rate of the hot water around the water-saving flow rate by the flow rate adjusting means. On the other hand, it can be controlled to a water-saving flow rate that achieves a predetermined water-saving rate, and by changing the flow rate around the water-saving flow rate, the user feels uncomfortable with the initial flow rate set by the user. Without water saving operation Door can be.

A second invention is, in particular, in the first invention, the flow rate of hot water flowing through the hot water supply conduit, so that the flow rate of the high side is the initial flow rate, and wherein the variation of Serco mainly water-saving rate Therefore, the initial flow rate can be felt in the flow rate fluctuation, and the water-saving operation can be performed with a sense closer to the same without feeling uncomfortable with the initial flow rate set by the user.

  The third invention is characterized in that, in the first or second invention, the water saving rate, flow rate fluctuation range, and fluctuation cycle with respect to the initial flow rate can be changed by remote control operation. Therefore, it is possible to select a fluctuation range and a cycle of the flow rate suitable for the bodily sensation, and to perform a water-saving operation without feeling uncomfortable with the feeling of use.

  According to a fourth aspect of the present invention, in particular, in any one of the first to third aspects of the invention, when the initial flow rate detected by the flow rate detection unit is equal to or less than a predetermined flow rate, the flow rate adjustment unit does not change the flow rate. However, if the detected flow rate of the flow rate detection means is less than the preset threshold flow rate, the initial flow rate set by the user is low and the feeling of use is inevitably controlled by controlling the water-saving flow rate. By not performing the water-saving operation in the flow rate range that decreases, it is possible to perform the water-saving operation only in the flow rate region where water saving is necessary, without causing discomfort due to the water-saving operation in the low flow region.

  5th invention is equipped with the person detection means which detects the person's entrance into a bathroom especially in any invention of the 1st-4th, and only when the said person detection means detects the person's entrance into the bathroom It is characterized by changing the flow rate, and by changing the flow rate only when the human detection sensor detects that a person is entering the room, especially when using a shower in a bathroom with a large flow rate It is possible to switch to automatic operation such as performing water-saving operation only, and not performing water-saving operation where flow rate fluctuations are a concern in the kitchen.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a configuration diagram of a hot-water storage type water heater with a bath reheating function according to the present embodiment. In FIG. 1, the hot water storage type hot water heater of the present embodiment includes a tank unit 1 and a heat pump unit 2, and heat pump unit 2 stores high temperature water stored in a hot water storage tank 3 disposed in the tank unit 1. It is generated by.

  In the present embodiment, a heat pump is used as the heating means. However, the present invention is not limited to this. For example, an electric heater may be provided in the tank and heated. Moreover, the solid line arrow has shown the direction through which the fluid flows.

  Next, the configuration of the heat pump unit 2 will be described.

  The heat pump unit 2 is configured by sequentially connecting a water-refrigerant heat exchanger 24, a compressor 25, an evaporator 26, and an expansion valve 27 in an annular manner through a refrigerant pipe, and uses carbon dioxide as a refrigerant. Since the high pressure side exceeds the critical pressure, the water flowing through the water / refrigerant heat exchanger 24 is deprived of heat and does not condense even if the temperature is lowered. A difference is easily formed, high-temperature hot water can be obtained, and heat exchange efficiency can be increased.

  In addition, since carbon dioxide, which is relatively inexpensive and stable, is used as the refrigerant, the product cost can be reduced and the reliability can be improved. In addition, carbon dioxide has an ozone depletion coefficient of zero and a global warming coefficient of about 1/700 of the alternative refrigerant HFC-407C, which is very small.

  Further, in the heat pump unit 2, the refrigerant is compressed by the compressor 25, the refrigerant discharged from the compressor 25 radiates heat by the water refrigerant heat exchanger 24, is decompressed by the expansion valve 27, and then is discharged from the air by the evaporator 26. The heat is absorbed and sucked into the compressor 25 again in a gas state.

  The compressor capacity control and the expansion valve 27 opening control are performed so that the temperature of the discharged refrigerant detected by a thermistor (not shown) provided on the discharge side of the compressor 25 is maintained at a preset temperature. Controlled. The hot water in the hot water storage tank 3 flows into the water / refrigerant heat exchanger 24 by the operation of the water pump 28, exchanges heat with the refrigerant, returns to the hot water storage tank 3 again, and in the stacked state, Hot water is stored at the top.

  Next, the configuration of the tank unit 1 will be described. As described above, the tank unit 1 has the hot water storage tank 3, and a water supply pipe 31 for supplying low temperature water from a water supply source is connected to the bottom of the hot water storage tank 3, so that the water supply pressure is constantly in the tank. It is in a hanging state. In addition, a hot water discharge pipe 32 for discharging hot water in the hot water storage tank 3 is connected to an upper portion of the hot water storage tank 3 so that high temperature water can be supplied to a hot water supply terminal and a bathtub.

  Next, a hot water supply circuit for supplying hot water to the hot water supply terminal will be described.

  The hot water supply circuit in the present embodiment is configured such that hot water having a desired temperature can be generated by connecting the terminal water supply pipe 33 branched from the water supply pipe 31 and the hot water discharge pipe 32 with the electric mixing valve 4. Then, the mixing ratio of the electric mixing valve 4 is changed so that the temperature detected by the temperature sensor 41 provided on the downstream side of the electric mixing valve 4 becomes the temperature set by the remote controller provided in the kitchen or bathroom. The Then, the hot water mixed at a desired temperature flows through a hot water supply line 40 including a flow rate detection means 43 such as a flow rate sensor and a flow rate adjustment means 44 such as a flow rate adjustment valve, and is supplied to the hot water supply terminal 42 and the shower 45. Is done.

  Next, a hot water filling circuit and a reheating circuit for the bathtub 5 will be described.

  In the present embodiment, the hot water in the bathtub 5 and the high-temperature water in the hot water storage tank 3 exchange heat with the heat exchanger 6 and have a reheating function for reheating the hot water in the bathtub. . Therefore, the high temperature side circuit of the reheating heat exchanger 6 is configured to be supplied with the high temperature water in the hot water storage tank 3, and is configured to return the hot water after heat exchange to the lower part of the hot water storage tank 3. Has been. Moreover, the low temperature side circuit of the reheating heat exchanger 6 is configured to be supplied with hot water in the bathtub 5, and is configured to return the bathtub water after the heat exchange to the bathtub 5 again. .

  In the high temperature side circuit, a temperature sensor 71 as a high temperature side outlet temperature detecting means is disposed downstream of the reheating pump 7 and the reheating heat exchanger 6, and the reheating pump 7 is driven to drive the hot water storage tank. The hot water in 3 is conveyed to the reheating heat exchanger 6.

  And the adapter 51 of the bathtub 5 and the tank unit 1 are connected by the return connection pipe 61 and the forward connection pipe 62 in the connection parts 60a-60d. The return connection pipe 61 and the forward connection pipe 62 are connected to the reheating heat exchanger 6 by a return pipe 63 and a forward pipe 64, respectively. The bathtub 5, the return connection pipe 61, the return pipe 63, The reheating heat exchanger 6, the outgoing pipe 64, and the outgoing connecting pipe 62 are sequentially connected to constitute a reheating circuit.

  The hot water filling circuit for supplying hot water from the hot water storage tank 3 to the bathtub 5 includes a bath hot water supply pipe 34 branched from the hot water supply pipe 32 and a bath water supply pipe 35 branched from the water supply pipe 31 to the electric mixing valve 8. And hot water having a desired temperature can be generated. The mixing ratio of the electric mixing valve 8 is changed so that the temperature detected by the temperature sensor 81 provided on the downstream side of the electric mixing valve 8 becomes the temperature set by the remote controller provided in the kitchen or bathroom. The Then, the hot water mixed at a desired temperature is supplied to the bathtub 5.

  Moreover, the flow rate sensor 82 is provided in the hot water filling circuit, and the amount of hot water supplied to the bathtub 5 is measured. Further, a two-way electromagnetic valve 83 is provided, and at the start of hot water filling, the supply of hot water to the bathtub 5 is started simultaneously with opening of the electromagnetic valve 83. After the electromagnetic valve 83 is opened, hot water filling is performed from two directions of the return pipe 63 and the forward pipe 64 to the bathtub 5. In addition, a check means 84 is provided for preventing the backflow of sewage.

  The return pipe 63 includes a bath pump 65 that is a conveying means for circulating hot water in the bathtub 5, a water level sensor 66 that detects the water level in the bathtub 5, and a bath temperature that detects the temperature of hot water in the bathtub 5. A temperature sensor 67 as a detection means is provided, and when the bath pump 65 is driven, hot water in the bathtub 5 is sucked into the return pipe 63 and flows into the forward pipe 64 via the reheating heat exchanger 6. It is returned to the bathtub 5 again.

  In addition, a flow switch 68 is provided between the bath pump 65 and the reheating heat exchanger 6 as hot water detection means for detecting whether there is hot water in the bathtub 5. Can be detected. That is, it is determined that there is hot water in the bathtub 5 when the flow switch 68 is turned on, and it is determined that there is no hot water in the bathtub 5 when the flow switch 68 is turned off.

  In addition, a remote control 9 that is a temperature setting means for setting the temperature of hot water in the bathtub 5 is installed in the bathroom, which is an operation means that can operate the hot water storage type water heater. Perform hot water temperature setting, bath filling, and trial operation after installation. The remote control 9 has a display unit 91 for displaying information and an operation unit 92 for performing operations.

  Although not shown in FIG. 1, the hot water storage type water heater of the present embodiment also has a control means 94 that receives an instruction from the remote controller 9 and commands each control device. The control means 94 is composed of a microcomputer and its electronic control parts, and sends commands to the devices constituting the tank unit 1.

  Furthermore, the remote control 9 of the present invention is provided with a person detecting means 93 so that it can detect that a person has entered the bathroom. As the human detection means 93, various sensors such as an infrared sensor, an illuminance sensor for detecting illuminance in the bathroom, and an impact (vibration) sensor for detecting vibration of a resident or opening / closing of a door can be used. Is not specified.

  In the hot water storage type water heater configured as described above, a water-saving operation when using hot water will be described.

  When the user starts hot water supply using the hot water supply terminal 42 or the shower 45, the flow rate detection means 43 of the hot water supply pipe line 40 detects the flow rate. When the user adjusts the used flow rate and the detected flow rate of the flow rate detecting means 43 is stabilized, the control means 94 learns the flow rate as the initial flow rate.

  A flow rate for obtaining a predetermined water saving rate (5% to 10%) set in advance by the control means 94 is calculated with respect to the initial flow rate, and the flow rate adjusting means 44 varies the flow rate around the flow rate. Regardless of the hot water source such as kitchen use or shower use and the purpose of use, control the water saving flow rate (time average value) that achieves a predetermined water saving rate with respect to the flow rate that the user wants to use with the device alone. By changing the flow rate around the water-saving flow rate, the water-saving operation can be performed without feeling uncomfortable with the initial flow rate set by the user (with an equivalent sense). .

  Furthermore, in the hot water storage type water heater, the amount of hot water stored in the tank can be reduced, energy for making the hot water can be saved, and occurrence of hot water in the tank can be suppressed.

  In addition, whether or not the user performs water-saving operation depends on usage conditions such as always performing water-saving operation, and only when the detected flow rate of the flow rate detection means 43 is equal to or greater than a predetermined threshold, and setting the mode with the remote controller 9. You can choose the method.

  By providing a predetermined threshold value for the detected flow rate of the flow rate detection means 43, in use in an area where the flow rate is originally low and the water saving effect is small, the water saving operation in the usage range where the flow rate decreases further and does not meet the purpose of use is performed. It can be canceled automatically, giving priority to the user's convenience.

  When setting the mode with the remote control 9, a dedicated SW can be provided on the operation unit 92 or selected from the setting menu, and the user can select whether or not to perform water-saving operation according to his / her purpose of use. Will be able to.

  Further, the water saving rate can be given a constant value to the control unit 94, can be switched according to the learning value of the initial flow rate, or can be set with the remote controller 9. In addition, during the water-saving operation, the display 91 of the remote controller 9 can be displayed to show that the shower is shaking, so that the user can see that the water-saving operation is being performed, or the water-saving operation mode can be displayed.

  Also, since there is a sense of incongruity when the flow rate fluctuates when using hot water such as washing in the kitchen, it is linked with human detection by the human detection means 93 of the remote control 9 so that water saving operation is performed only when using a shower in the bathroom. Thus, the flow rate can be changed due to the water-saving operation. When people are not being detected, it is possible to control only the water-saving flow rate.

  FIG. 2 is a flowchart of hot water use during water saving operation. At time T1, the user starts hot water supply and adjusts the flow rate to be used. At time T2, the flow rate is adjusted to Ra, and the detected flow rate of the device is stabilized. If the state where the flow rate is stable continues for a predetermined time ΔT, the flow rate is learned as the initial flow rate Ra, and the water-saving flow rate Rs at which a predetermined water-saving rate is obtained with respect to Ra is calculated.

  When the predetermined water saving rate is Z%, Rs = Ra × (1−Z / 100). Then, from time T3 after lapse of ΔT, the flow rate is changed so that one cycle of fluctuation becomes Ts with amplitude ± d of a predetermined flow fluctuation width centering on the calculated water-saving flow rate Rs.

  In this case, the flow rate fluctuation period is 1 / TsHz. If the flow rate fluctuation period is short, the upper and lower limits of the flow rate fluctuation are difficult to feel and it is difficult to understand that the flow rate has decreased.

  Conversely, when the flow rate fluctuation period becomes longer, it becomes easier to feel the upper limit / lower limit of the flow rate fluctuation, and it becomes easier to feel the lack of the low flow rate at the lower limit, and the flow rate feels inferior to the initial flow rate. For this reason, the time Ts of 1 period is set so that a flow volume fluctuation | variation period may be set to 0.5-3 Hz from the result of a bodily sensation test.

  In this way, by controlling the flow rate by changing the flow rate around the water-saving flow rate Rs, the water-saving operation can be performed without feeling uncomfortable with the initial flow rate set by the user.

  For example, when water saving operation is performed with an initial flow rate Ra of 10 L / min, a predetermined water saving rate of 10%, a flow rate fluctuation range of ± 0.5 L / min, and a cycle of 0.5 seconds, the water saving flow rate Rs is 9 L / min. Thus, the flow rate fluctuation of the upper limit of 9.5 L / min and the lower limit of 8.5 L / min is performed at a cycle of 1 Hz.

  FIG. 3 is a flowchart of hot water use during water-saving operation when the upper limit flow rate of flow rate variation is set to the initial flow rate. In this case, by learning the initial flow rate Ra, the water-saving flow rate Rs for setting the predetermined water-saving rate Z% is calculated, and the upper limit flow rate is the initial flow rate Ra, so the amplitude of the flow rate fluctuation range is set to d = Ra × Z / 100 can be calculated.

  Thereby, the lower limit flow rate fluctuation can also be calculated. As a result, when the amplitude of the flow rate fluctuation is given at a predetermined fixed value, the ratio of the amplitude is too large when the flow rate is small, and the fluctuation is not felt when the flow rate is large. There is a case where the flow rate drop is felt strongly, but if the flow rate fluctuation range can be determined with respect to the initial flow rate in this way, the amplitude of the flow rate fluctuation at a rate corresponding to the used flow rate can be given, thereby saving water. You can drive without feeling uncomfortable.

Further, the upper limit of the flow rate fluctuation can be set to the initial flow rate, and the water-saving operation can be performed with a sense closer to the same without feeling dissatisfied with the initial flow rate set by the user.

  As the initial flow rate increases, the flow rate fluctuation range correspondingly increases. However, if the amplitude of the flow rate change becomes too large due to a bodily sensation such as a shower, there may be a case where the user feels it. Therefore, if the flow rate fluctuation range is given an upper limit and the initial flow rate exceeds a certain flow rate and the calculated flow rate fluctuation range exceeds the upper limit value of the flow rate fluctuation range, the flow rate fluctuation is performed with the set upper limit amplitude of the flow rate fluctuation. It is possible to put in such a control.

  FIG. 4 is a flowchart of the use of hot water supply during a water-saving operation when the water-saving rate relative to the initial flow rate, the fluctuation range of the flow fluctuation, and the fluctuation cycle are switched by remote control operation. It is assumed that the water saving “large” mode and the water saving “small” mode are switched by remote control operation.

  The water saving rate of the water saving “large” mode is double the water saving rate Z% of the water saving “small” mode. Conversely, the time of one cycle is 2 Ts seconds for the water saving “small” mode compared to Ts seconds of the water saving “large” mode. Yes. The amplitude of the flow rate fluctuation is set so that the upper limit flow rate becomes the initial flow rate.

  The water-saving “large” mode increases the water-saving rate and correspondingly increases the amplitude of flow rate fluctuation, but shortens the cycle to make it difficult to feel the upper and lower limits of the flow rate. In the water saving “small” mode, the water saving rate is reduced to reduce the flow fluctuation range, and the cycle is lengthened to make the flow fluctuation mild.

  Depending on the user, the comfort during use differs depending on the magnitude of the flow rate amplitude and the fluctuation cycle, but by switching the water-saving operation mode in this way, the user can consider the purpose of use, the feeling of use, and the water-saving effect, and suit him / herself. Can save water. It is also conceivable that the water saving rate and cycle can be changed not by mode switching but by remote control operation.

  FIG. 5 is an example of changes in each flow rate by switching the water saving rate and the amplitude of the flow rate fluctuation between the initial flow rate and the water saving operation. The water saving rate of the large water saving mode is 10%, the period is 2 Hz, the upper limit amplitude of flow fluctuation is ± 1 L / min, the water saving rate of the water saving “small” mode is 5%, the period is 1 Hz, and the upper limit amplitude of flow fluctuation is ± 0.5 L / min. The amplitude of the flow rate fluctuation is set so that the upper limit flow rate becomes the initial flow rate in both the water saving “large” and “small” modes.

  In general, the proper flow rate for dishwashing in a kitchen is about 5 L / min, and the proper flow rate for a shower is around 10 L / min. Therefore, the threshold flow rate for water-saving operation assuming a water-saving operation when using a shower is 6 L / min. The flow rate fluctuation operation is not performed at a low flow rate of less than 6 L / min, such as in kitchen use.

  In the case of 10% water saving in the water saving “large” mode, when the flow rate is 10 L / min, the amplitude of the flow rate fluctuation is 1 L / min, which is the upper limit amplitude of the flow rate fluctuation. For this reason, when 10% of water saving is large, when the initial flow rate is 10 L / min or more, the amplitude is ± 1 L / min and the water saving rate is less than 10%. When the initial flow rate is less than 10 L / min, the amplitude is ±± of the initial flow rate. Operate at 10% and 10% water saving.

  Similarly, in the case of 5% water saving in the water saving “small” mode, when the flow rate is 10 L / min, the amplitude of the flow rate fluctuation is 0.5 L / min, which is the upper limit amplitude of the flow rate fluctuation. For this reason, when 5% of the water is saved, the initial flow rate is 10L / min or more, the amplitude is ± 0.5L / min. The water saving rate is less than 5%, and the initial flow rate is less than 10L / min, the amplitude is the initial flow rate. Operate at ± 5% and water saving rate of 5%.

  In this way, by switching the water saving rate and the amplitude of flow fluctuations, specifying the threshold, the upper limit flow rate of the amplitude, etc., the water saving operation is automatically selected according to the purpose of use, and the user can select the water saving rate and his / her experience. The water-saving operation mode suitable for the vehicle can be selected, and the water-saving operation can be performed without feeling uncomfortable with the feeling of use.

  FIG. 6 is a flowchart for switching the water-saving operation by human detection by the human detection means 93 provided in the remote controller 9 of the bathroom. When the person is not bathing and there is no person in the bathroom, the detection of the person detecting means 93 is off. In this state, the water-saving operation is not performed even if hot water having a threshold flow rate or more is used in the kitchen.

  When a person enters the bathroom for bathing at time Tn, the detection of the person detecting means 93 is turned on. Even in this state, the water-saving operation is not performed when using a small amount of hot water supply that is less than or equal to the threshold flow rate. When the shower use is started at Ts and the detected flow rate of the water amount sensor is stabilized at the flow rate Ra equal to or higher than the threshold flow rate, the flow rate is learned as an initial flow rate, and water saving operation is performed.

  In this way, by performing water-saving operation in response to detection of people in the bathroom, the water-saving operation is performed only when using a shower in a bathroom that is used at a large flow rate, and the usage state where flow fluctuations are an issue in the kitchen etc. Then, it is possible to automatically switch not to perform the water-saving operation, and it is possible to perform the water-saving operation without giving the user an uncomfortable feeling corresponding to the purpose of use.

  As described above, the water heater according to the present invention calculates the water-saving flow rate that achieves a predetermined water-saving rate with respect to the flow rate that the user wants to use regardless of the destination and purpose of use, and is set by the user. Since the water saving operation at the water saving flow rate can be performed by the device alone with the same feeling as the initial flow rate, it can be applied to the water saving operation using a hot water supply means or a water supply means other than the hot water storage type.

DESCRIPTION OF SYMBOLS 1 Tank unit 2 Heat pump unit 3 Hot water storage tank 9 Remote control 40 Hot-water supply line 42 Hot-water supply terminal 43 Flow rate detection means 44 Flow rate adjustment means 93 Person detection means 94 Control means

Claims (5)

A hot water supply pipe for supplying hot water to a hot water supply terminal, a flow rate detecting means for detecting a flow rate of hot water flowing through the hot water supply pipe, a flow rate adjusting means for adjusting the flow rate of hot water flowing through the hot water supply pipe, and a control means. And the flow rate of the hot water flowing through the hot water supply pipe line is such that the flow rate of the hot water flowing through the hot water supply pipe line becomes a water saving flow rate calculated from a predetermined water saving rate with respect to the initial flow rate detected by the flow rate detecting means. The water heater is characterized in that the water flow rate is varied by the flow rate adjusting means. The hot water flow through the hot water supply conduit, often as the flow rate of the side is the initial flow rate, the water heater according to claim 1, wherein the variation of Serco around the water-saving rate. The water heater according to claim 1 or 2, wherein the water saving rate, flow rate fluctuation range, and fluctuation cycle with respect to the initial flow rate can be changed by remote control operation. The water heater according to any one of claims 1 to 3, wherein when the initial flow rate detected by the flow rate detection means is equal to or less than a predetermined flow rate, the flow rate adjustment means does not change the flow rate. 5. The apparatus according to claim 1, further comprising a human detection unit that detects a person entering the bathroom, wherein the flow rate is changed only when the person detection unit detects a person entering the bathroom. The water heater described in the paragraph.