JP2011257096A - Water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water heater for achieving water-saving operation while maintaining the usability thereof by varying the flow rate thereof to reach a certain water-saving rate with respect to the usage flow rate set by a user.SOLUTION: The water heater includes: a hot water supply pipe passage 40 for supplying hot water to a hot water supply terminal 42; a flow rate detecting means 43 for detecting the flow rate of the hot water flowing in the hot water supply pipe passage 40; a flow regulator 44 for regulating the flow rate of the hot water flowing in the hot water supply pipe passage 40; and a control means 94. The water heater is configured such that the flow rate detecting means 43 detects, in an operation where the flow rate regulating means 44 periodically varies the flow rate of the hot water flowing in the hot water supply pipe passage 40, a flow rate when the flow rate of the hot water is reduced according to an initial flow rate detected by the flow rate detector 43, so that the flow rate of the hot water flowing in the hot water supply pipe passage 40 becomes a water saving flow rate calculated based on a predetermined water saving rate with respect to the initial flow rate.

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 that is lower than the maximum value. 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-mentioned conventional problems, and hot water supply that realizes water-saving operation while maintaining usability by changing the flow rate to a predetermined water-saving rate with respect to the flow rate set by the user. The purpose is to provide a machine.

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. In the operation in which the flow rate of the hot water flowing through the hot water supply pipe is periodically changed by the flow rate adjusting means so as to be a water-saving flow rate, when the flow rate of the hot water is reduced from the initial flow rate, the flow rate detection means detects the flow rate. It is characterized by performing.

  In this way, in the operation of periodically changing the flow rate of the hot water flowing through the hot water supply pipe with the flow rate adjusting means so as to be the water saving flow rate calculated from the predetermined water saving rate with respect to the initial flow rate detected by the flow rate detecting means, Even if the use flow rate changes due to the user's operation or the like, by detecting the flow rate again, the water-saving operation can be performed without feeling uncomfortable with the flow rate changed 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 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 (A) Other water-saving operation flowchart in the first embodiment of the present invention (when the flow rate increases) (b) Other water-saving operation flowchart in the same mode (when the flow rate decreases) Other water-saving operation flowchart 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 in the same form 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 In the operation of periodically changing the flow rate of the hot water flowing through the flow rate adjusting means, when the flow rate of the warm water is reduced from the initial flow rate, the flow rate detection means performs flow rate detection. .

  In this way, in the operation of periodically changing the flow rate of the hot water flowing through the hot water supply pipe with the flow rate adjusting means so as to be the water saving flow rate calculated from the predetermined water saving rate with respect to the initial flow rate detected by the flow rate detecting means, Even if the use flow rate changes due to the user's operation or the like, by detecting the flow rate again, the water-saving operation can be performed without feeling uncomfortable with the flow rate changed by the user.

  The second invention is characterized in that, in particular, in the first invention, when the flow rate of hot water flowing through the hot water supply pipe is varied with the water-saving flow rate as a central value, the flow rate on the larger side is set to be equal to or greater than the initial flow rate. Therefore, it is possible to feel a flow rate higher than the initial flow rate in the flow rate fluctuation, and to experience water-saving operation with a feeling close to the same level without feeling uncomfortable with the initial flow rate set by the user. It can be carried out.

  In particular, the third invention is the first or second invention, further comprising human detection means for detecting a person entering the bathroom, and the flow rate is detected only when the person detection means detects a person entering the bathroom. It is characterized by fluctuations, and it saves water only when using a shower in a bathroom with a large flow rate, by changing the flow rate only when the human detection sensor detects that a person is entering the room. It is possible to switch to automatic operation such as not performing water-saving operation when the operation is performed and the flow rate fluctuation is 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 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 for heating. 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. To be 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 means 94, can be switched by the learning value of the initial flow rate, or can be set by 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 the lapse of ΔT, the flow rate is changed so that one cycle of fluctuation becomes Ts with the amplitude ± d of the predetermined flow fluctuation width around the calculated water-saving flow rate Rs.

  In this case, the flow rate fluctuation period is 1 / TsHz. If the flow rate fluctuation cycle is short, it is difficult to feel the upper and lower limits of the flow rate fluctuation, and it is difficult to understand that the flow rate is decreasing, but the flow rate does not fluctuate and the shower is taken, and there is no calmness and the physical comfort is lost.

  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 rate fluctuation period may be set to 0.5-3 Hz from the result of a 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.

  In addition, the upper limit of the flow rate fluctuation can always be greater than or equal 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 value 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 set with the upper limit amplitude of the set flow rate fluctuation. It is also possible to put control such as performing.

  FIG. 4 is a flowchart when a user operation or the like is performed during detection of the lower limit flow rate during the water-saving operation when the upper limit flow rate of the flow rate change is set to the initial flow rate. Normally, as shown by the broken line in FIG. 4, the flow rate detecting means 43 detects the initial flow rate, calculates the water saving flow rate and the lower limit flow rate from the initial flow rate and a predetermined water saving rate, and the flow rate detecting means 43 sets the lower limit flow rate. The flow rate adjusting means 44 adjusts the flow rate used until the flow rate is detected, but when the flow rate increases, as shown in FIG. The upper limit flow rate becomes larger than the initial flow rate, and the set flow rate fluctuation cannot be realized. On the other hand, as shown in FIG. 4B, when the flow rate decreases due to the user's operation or the like, the lower limit flow rate is detected immediately, and the set flow rate fluctuation cannot be realized.

  FIG. 5 is a countermeasure flowchart for a phenomenon in which the flow rate fluctuation width that occurs when these unscheduled operations are performed. When the flow rate detecting unit 43 detects the lower limit flow rate, if an increase in the used flow rate is detected by a user operation or the like, or if a decrease in the used flow rate is detected, the initial flow rate is again shown in the figure. It is possible to perform a water-saving operation that satisfies the comfort by calculating the water-saving flow rate from the predetermined water-saving rate as described above.

  FIG. 6 is a flowchart of a detection method when there is a change in flow rate due to a user operation or the like during detection of the lower limit flow rate. Depending on the installation environment, the water pressure supplied to the water heater itself may fluctuate, which may cause the flow rate to change during the lower limit detection. It is also conceivable to detect a change in the usage flow rate by a fine adjustment operation by the user.

  That is, when the flow rate exceeds a certain initial flow rate in addition to the detected initial flow rate, it is determined that the flow rate has increased, or even if the flow rate during detection of the lower limit flow rate is less than or equal to the initial flow rate, If the reduction rate is more than a certain value, the flow rate is judged to be reduced.

  In this way, a predetermined standard is set in advance for determining the change in the used flow rate, the initial flow rate is detected again, and the water-saving flow rate is calculated from the predetermined water-saving rate as described above. It is possible to supply a comfortable water-saving operation without giving any water.

  FIG. 7 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 and the flow rate fluctuation width is reduced, and the cycle is extended to make the flow rate 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. 8 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. 9 is a flowchart of switching 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 detection 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 (3)

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. In the operation of periodically varying the flow rate adjusting means, when the flow rate of the hot water is reduced from the initial flow rate, the flow rate detecting means performs flow rate detection. 2. The water heater according to claim 1, wherein when the flow rate of hot water flowing through the hot water supply pipe is varied with the water-saving flow rate as a central value, the flow rate on the larger side is set to be equal to or higher than the initial flow rate. The flow rate fluctuation is performed only when the person detecting means for detecting a person entering the bathroom is detected, and the person detecting means detects a person entering the bathroom. Water heater.