JP4458195B1 - Hot water storage water heater - Google Patents

Abstract

To provide a hot water storage type hot water heater capable of reducing heat radiation from a bathtub and reducing the number of reheating operations of the bathtub by keeping the temperature of the bathtub low when there is no person in the bathroom.
A hot water storage tank 57 for storing hot water, a remaining hot water temperature detecting means 86 for detecting a remaining hot water temperature in the hot water storage tank 57, a heating means 55 for generating high temperature water stored in the hot water storage tank 57, and a bathtub 68. The hot water in the hot water storage tank 57 and the hot water in the bathtub 68 exchange heat so that the bath heat exchanger 73 that heats the hot water in the bathtub 68 and the presence of a person in the bathroom 80 are detected. Human detection means 81 and control means 82, and when the human detection means 81 does not detect the presence of a person in the bathroom 80, the bath heat exchanger 73 is used to follow the hot water in the bathtub 68. The hot water storage type hot water heater is characterized in that the starting operation temperature for burning is changed based on the temperature detected by the remaining hot water temperature detecting means 86.
[Selection] Figure 1

Description

  The present invention relates to a hot water storage type water heater having a bath retreat function.

  Conventionally, as this type of water heater, there is one having a reheating function of a bathtub using hot water of a hot water tank (see, for example, Patent Document 1).

  FIG. 4 shows a conventional water heater described in the publication. As shown in the figure, this hot water supply machine includes a compressor 1, a heat pump unit 4 including a hot water supply heat exchanger 2 and an evaporator 3 which are refrigerant to water heat exchangers, a hot water tank 5 and water to water heat. The hot water supply unit 7 includes a bath heat exchanger 6 that is an exchanger. The hot water storage tank 5 stores hot water heated by the heat pump unit 4 using the hot water supply heat exchanger 2.

  The hot water in the hot water tank 5 is poured into the bathtub 9 and filled with hot water through the bathtub pouring pipeline 8 and the bath circulation pipe 10 connecting the bathtub 9 and the hot water storage unit 7. The bath heat exchanger 6 heats the hot water in the bathtub 9 by circulating the hot water in the hot water tank 5.

  That is, hot water pumped from the heat source side circulation pump 11 from the upper part of the hot water tank 5 is led to the bath heat exchanger 6 to heat the hot water or water in the bathtub 9 pumped by the use side circulation pump 12. After that, the hot water from the hot tub 9 is returned to the hot tub 5, while the hot water from the hot tub 9 is returned to the tub 9, so that the bath is replenished.

  Furthermore, it is configured so that hot water can be supplied by opening the faucet 13. With such a configuration, an appropriate amount of hot water is poured from the hot water storage tank 5 into the bathtub 9 to fill the bathtub 9, and then the hot water in the bathtub 9 is chased to an appropriate temperature for a predetermined time. The automatic bath operation will be described.

In this case, after filling the hot water, the user-side circulation pump 12 is driven at regular time intervals,
Hot water in the bathtub 9 is circulated to the hot water storage unit 7 side, and a bathtub temperature detection operation is performed in which the temperature of the bathtub 9 is detected by the bathtub temperature detection means 14. At this time, if the temperature of the bathtub 9 is lower than the appropriate temperature range, the bath chasing operation is performed, and if it is within the appropriate temperature range, the bath chasing operation is not performed.
JP 2002-243275 A

  However, the conventional configuration has the following problems. As described above, the bathtub temperature detection operation is performed at regular time intervals (for example, every 15 minutes). However, the timing of the bath temperature detection operation is performed regardless of the timing at which a person bathes.

  FIG. 5 shows the temperature change of the bathtub 9 during the automatic bath operation, with the elapsed time during the automatic bath operation as the horizontal axis and the temperature of the bathtub 9 as the vertical axis. In the figure, TU is a heat retention upper limit temperature, and if the temperature of the bathtub 9 is equal to or higher than this temperature, the bath replenishment is terminated.

  Moreover, TL is a heat retention lower limit temperature, and is a temperature at which bath reheating starts when the temperature of the bathtub 9 is equal to or lower than this temperature. Furthermore, in order to detect the temperature of the bathtub 9, a bath temperature detection operation is performed every time interval t. In the bathtub temperature detection operation, the use-side circulation pump 12 is driven to circulate the hot water in the bathtub 9 toward the hot water storage unit 7, and the bathtub temperature detection means 14 detects the temperature of the bathtub 9.

  In the figure, the first half of the elapsed time shows a case where there is a person in the bathroom (not shown), and the second half shows a case where there is no person in the bathroom. As shown in the figure, the temperature of the bathtub 9 is maintained by performing the bath temperature detection operation and performing the bath chasing operation in the same manner regardless of whether there is a person in the bathroom.

  Wasteful energy was consumed in order to keep the temperature of the bathtub 9 at an appropriate temperature in preparation for bathing when a person is not present. In particular, when there is no bathing for a long time, most of the energy for keeping the bath warm is consumed, and there is a problem that the heat keeping efficiency of the bath is poor.

  In addition, when bathing suddenly in a cold body such as winter, even if the bathtub is kept within the range of the heat retention upper limit temperature and the heat retention lower limit temperature, it may be felt hot and there may be a problem in comfort.

  In addition, if the bath automatic operation continues for a long time, the time for bath renewal operation increases, and the hot water at the top of the hot water tank 5 is used as a heat source for bath renewal. There was a problem in convenience and comfort.

  In addition, the hot water at the top of the hot water tank 5 that is a heat source for bathing heat is exchanged with the hot water in the bathtub 9 by the bath heat exchanger 6 and becomes a medium temperature of about 40 to 50 ° C. Return to the part. And since this medium temperature hot water mixes with the low temperature hot water or water of the hot water tank 5 and raises the temperature of the hot water tank, the efficiency when heating the water of the hot water tank 5 using a heat pump is reduced. There was a problem.

  The present invention solves the above-mentioned problem. When it is determined whether a person is in the bathroom or not, if it is determined that the person is not present, the useless bathing is reduced. The purpose of the present invention is to provide a hot water storage type water heater that improves the heat insulation efficiency and improves the comfort, convenience, and hot water supply efficiency.

In order to solve the above-mentioned conventional problems, a hot water storage type water heater of the present invention includes a hot water storage tank for storing hot water, a remaining hot water temperature detecting means for detecting a remaining hot water temperature of the hot water storage tank, and a high temperature stored in the hot water storage tank. Heating means for generating water, a bathtub, a hot water in the hot water tank and a hot water in the bathtub to exchange heat, a bath heat exchanger for heating the hot water in the bathtub, and a person in the bathroom The bath heat exchanger replenishing operation with the bath heat exchanger is performed when the human detection means does not detect the presence of a person in the bathroom. The starting temperature is characterized by setting a lower temperature when the temperature detected by the remaining hot water temperature detecting means is higher than when the temperature is higher , and depending on the remaining hot water temperature, The control temperature can be set to the optimum temperature, which improves the heat insulation efficiency of the bath. It can be achieved.

  According to the present invention, it is determined whether or not a person is in the bathroom, and if it is determined that there is no person, the replenishment of useless bath is reduced, and if a person is detected, the heat insulation efficiency of the bath is improved. Therefore, it is possible to provide a hot water storage type water heater that improves comfort, convenience, and efficiency of hot water supply.

The first invention includes a hot water storage tank for storing hot water, a remaining hot water temperature detecting means for detecting a remaining hot water temperature in the hot water storage tank, a heating means for generating high temperature water stored in the hot water storage tank, a bathtub, and the hot water storage Hot water in the tank and hot water in the bathtub exchange heat, a bath heat exchanger that heats the hot water in the bathtub, a human detection means that detects the presence of a person in the bathroom, and a control means, The temperature detection means detects the temperature of the reheating operation of the hot water in the bathtub by the bath heat exchanger, which is performed when the person detection means does not detect the presence of a person in the bathroom. The lower temperature is set to a higher temperature than the higher temperature .

Thereby, according to the remaining hot water temperature, the control temperature when there is no person can be set to an optimum temperature, and the heat insulation efficiency of the bath can be improved.

According to the second aspect of the invention, the temperature of the hot water in the bathtub by the bath heat exchanger, which is performed when the human detection means detects the presence of a person, does not change based on the temperature detected by the remaining hot water temperature detection means. Therefore, it is possible to maintain comfort when there are people in the bathroom .

According to a third aspect of the present invention, the temperature at which the hot water in the bathtub is stopped by the bath heat exchanger performed when the human detection means does not detect the presence of a person is constant regardless of the temperature detected by the remaining hot water temperature detection means. When the remaining hot water temperature is high, the number of times of bathing is reduced and the heat insulation efficiency of the bath can be improved.

According to a fourth aspect of the present invention, the temperature at which the hot water in the bathtub is reheated by the bath heat exchanger, which is performed when the human detection means does not detect the presence of a person, is performed when the human detection means detects the presence of a person. It is characterized by the fact that it is set to a temperature lower than the temperature at which the bath water is reheated by the bath heat exchanger. When there are no people in the bathroom, the amount of heat released from the bath can be reduced and the heat retention efficiency is improved. Can be achieved.

5th invention performs the reheating operation start temperature of the hot water of the bathtub by the bath heat exchanger performed when the human detection means does not detect the presence of the person when the human detection means detects the presence of the person It is characterized by the fact that it is set to a temperature lower than the temperature at which the bath water is reheated by the bath heat exchanger. When there are no people in the bathroom, the amount of heat released from the bath can be reduced, improving the heat insulation efficiency. Can be achieved.

In the sixth aspect of the invention, since the heat pump is used as the heating means, high efficiency and global environmental conservation can be achieved.

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 in the first embodiment of the present invention.

  In FIG. 1, a heating means 55 that is a heat source of a hot water storage type hot water supply device is a heat pump unit that constitutes a heat pump cycle including a compressor 51, a hot water supply heat exchanger 52, a decompression device 53, and an evaporator 54 that absorbs atmospheric heat. .

  Then, carbon dioxide whose refrigerant pressure on the high pressure side is equal to or higher than the critical pressure is used as the refrigerant. Water is supplied to the hot water storage tank 57 stored in the hot water storage unit 56 through a water supply pipe 58 connected to the lower part of the hot water storage tank 57, and hot water in the upper part of the hot water storage tank 57 passes through the hot water supply pipe 59 and is supplied by the hot water supply mixing valve 60. Then, hot water is supplied from the terminal (faucet 62) through the hot water supply pipe 61.

  Further, by forming a boiling circuit that sequentially connects the lower part of the hot water tank 57 to the circulation pump 63, the hot water supply heat exchanger 52, and the upper part of the hot water tank 57, the water sent from the hot water tank 57 by the circulation pump 63 is The hot water supply heat exchanger 52 is heated by the refrigerant heat and stored from above the hot water storage tank 57. A boiling temperature detecting means 64 is provided at the water-side outlet of the hot water supply heat exchanger 52 in order to detect the hot water temperature heated by the heat pump heat source as the heating means 55.

  Further, a bathtub pouring pipe 67 branching from the outlet pipe 59 and having a bath hot water mixing valve 65 and a bath pouring valve 66 is connected to a bathtub 68 by a bath circulation pipe 69. The bath circulation pipe 69 includes a bath going-out pipe 70 and a bath return pipe 71.

  The bath heating means 72 includes a bath heat exchanger 73 that is a water-water heat exchanger, a heat source side water circuit 74 and a use side water circuit 75 connected thereto, and the heat source side and use side water circuits 74 and 75. The heat source side circulation pump 76 and the use side circulation pump 77 are provided. The heat source side water circuit 74 is connected to the upper and lower parts of the hot water tank 57, and the use side water circuit 75 is connected to the bath circulation pipe 69.

  Further, the use side water circuit 75 is provided with a bathtub temperature detecting means 78 for detecting the temperature of the bathtub 68 and a bathtub water level detecting means 79 for detecting the water level of the bathtub 68. Heating of the bathtub 68 was sent from the hot water storage tank 57 to the bath heat exchanger 73 by the heat source side circulation pump 76 and from the bathtub 68 to the bath heat exchanger 73 by the use side circulation pump 77. It is carried out by heat exchange with water or hot water.

  The bathroom 80 is provided with a person detection means 81 for detecting a person in the bathroom. The control means 82 controls the operation of the hot water storage type hot water heater, and includes a first control means 94, a second control means 95, a control switching means 96, an upper and lower limit temperature setting means 97, and the like. Further, the bathtub temperature setting means 83 is a means for setting the desired hot water temperature of the bathtub 68.

  Also, a hot water supply temperature detection means 84 for detecting the hot water supply temperature mixed by the hot water supply mixing valve 60 is provided on the mixing outlet side of the hot water supply mixing valve 60, and a bath hot water temperature detection means for detecting the bath hot water temperature mixed by the bath hot water mixing valve 65. 85 is provided on the mixing outlet side of the bath hot water mixing valve 65. Furthermore, the remaining hot water temperature detection means 86 detects the temperature of the upper position of the hot water tank 57. The human detection means 81 includes an infrared sensor.

  About the hot water heater comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  In FIG. 1, first, the hot water supply heating operation will be described. If there is a request (not shown) for boiling the hot water storage tank 57, a hot water supply heating operation using atmospheric heat is performed by the heat pump unit which is the heating means 55. In this case, high-temperature and high-pressure refrigerant discharged from the compressor 51 flows into the hot water supply heat exchanger 52 where heat is exchanged with the water sent from the lower part of the hot water tank 57 to dissipate heat, and then the pressure is reduced. The pressure is reduced by the device 53, and heat is absorbed from the atmosphere by the evaporator 54, gasified, and returned to the compressor 51.

  At this time, the water sent from the lower part of the hot water storage tank 57 flowing into the hot water supply heat exchanger 52 controls the rotation speed of the circulation pump 63 so that the temperature at the outlet of the hot water supply heat exchanger 52 becomes a predetermined temperature. As a result, hot water of a predetermined temperature flows from the upper part of the hot water storage tank 57 and is stored.

  Next, a bathtub temperature detection operation for detecting the temperature of the bathtub 68 will be described.

  In this operation, the use side circulation pump 77 is driven to circulate hot water in the bathtub 68 with the hot water storage unit 56. And after circulating for a certain fixed time (for example, 1 minute), the temperature of the hot water of the bathtub 68 is detected by the bathtub temperature detection means 78. It is determined whether or not the detected temperature is within the control temperature range of the bathtub 68 determined from the temperature set by the bathtub temperature setting means 83.

  The upper and lower limit temperature setting means 97 sets the heat retention upper limit temperature which is the upper limit temperature of the control temperature range of the bathtub 68 and the heat retention lower limit temperature which is the lower limit temperature. That is, if the temperature is equal to or lower than the heat retention lower limit temperature of the control temperature, the bath temperature detection operation is terminated and the next bath reheating operation is started. On the other hand, if the detected temperature is higher than the heat retention lower limit temperature, the bathtub temperature detection operation is terminated, and the process waits until the next bathtub temperature detection operation.

  Next, a bath reheating operation for heating the hot water in the bathtub 68 will be described.

  The temperature of the bathtub 68 desired by the user is set by the bathtub temperature setting means 83. In general, a remote controller of a hot water storage type water heater is installed in a bathroom 80 or a kitchen (not shown). In many cases, the bath temperature setting means 83 is provided in the bathroom remote controller 87 installed in the bathroom 80. The bathtub temperature setting means 83 may be provided on a kitchen remote controller (not shown) installed in the kitchen. As described above, if the temperature detected by the bathtub temperature detecting means 78 is equal to or lower than the heat retention lower limit temperature of the control temperature, the bath reheating operation is performed.

  That is, the heat source side circulation pump 76 and the use side circulation pump 77 are driven. The hot water sent from the bathtub 68 by the use side circulation pump 77 is heated by heat exchange with the hot water in the upper part of the hot water tank 5 sent by the heat source side circulation pump 76 and the bath heat exchanger 73, and the temperature rises. Return to the bathtub 68. On the other hand, the hot water from the hot water storage tank 57 that has heated the hot water from the bathtub 68 by the bath heat exchanger 73 decreases to a medium temperature hot water of about 40 to 50 ° C. and returns to the lower part of the hot water storage tank 57.

  At this time, the bathtub temperature detecting means 78 detects the temperature of the hot water in the bathtub 68 sent by driving the use side circulation pump 77. And if this detected temperature is lower than the heat retention upper limit temperature of the said control temperature determined from the bathtub setting temperature set by the bathtub temperature setting means 83, a bath chasing operation will be continued as it is. And if the detected temperature becomes more than the heat retention upper limit temperature of the said control temperature, a bath chasing operation will be complete | finished.

Further, an automatic bath operation will be described in which an appropriate amount of hot water is filled in the bathtub 68 and then the bath 68 is kept warm for a predetermined time. At this time, the desired bathtub temperature, the amount of hot water in the bathtub, and the heat retention time can be set. The temperature of the bathtub desired by the user, the amount of hot water in the bathtub, and the warming time are respectively set to the bath temperature setting means 83, the bath hot water setting means (not shown), and the warming time setting means (not shown).
To do.

  In general, the remote controller of the water heater is installed in a bathroom 80 or a kitchen (not shown), and the bathtub remote control 87 installed in the bathroom 80 is provided with the bathtub temperature setting means 83, the bathtub hot water amount setting means, and the warming time setting means. Often configured. In addition, you may provide these setting means in the kitchen remote control (not shown) installed in the kitchen.

  Further, the person detecting means 81 may be installed alone, but as shown in FIG. In this case, since it is not necessary to install the person detecting means 81 and the bathroom remote controller 87 separately, there is an advantage that the workability is improved.

  When the bath automatic operation is started, the bathtub 68 is filled with water by pouring from the hot water tank 57 to the bathtub 68 so that the temperature and the amount of hot water set by the bathtub temperature setting means 83 and the bathtub hot water amount setting means are obtained. . That is, the control means 82 opens the bath pouring valve 66 and starts pouring.

  Then, the mixing ratio of the bath / hot water mixing valve 65 is controlled based on the signal from the bath / hot water temperature detecting means 85 so that the temperature of the bathtub 68 becomes the temperature set by the bathtub temperature setting means 83. If the water level detected by the bathtub water level detection means 79 becomes a water level corresponding to the amount of hot water set by the bathtub hot water volume setting means, the control means 82 ends the hot water filling operation. After that, if the temperature of the bathtub 68 decreases according to the time set by the heat retention time setting means, the bath 68 is swept away to perform the heat insulation operation.

  First, a case where there is no person in the bathroom 80 will be described. The upper and lower limit temperature setting means 97 sets a heat retention upper limit temperature that is the upper limit temperature of the control temperature range of the bathtub 68 and a heat retention lower limit temperature that is the lower limit temperature. And if the bathtub temperature detection operation is performed for every time interval t and the bathtub temperature detected by the bathtub temperature detection means 78 is higher than the heat insulation lower limit temperature of control temperature, a bathtub temperature detection operation will be complete | finished and the next bathtub temperature will be complete | finished. Wait until detection operation.

  On the other hand, if the detected bath temperature is equal to or lower than the heat retention lower limit temperature of the control temperature, the bath reheating operation is performed until the bath temperature reaches the heat retention upper limit temperature of the control temperature. Here, the lower temperature limit of heat retention differs depending on the temperature of hot water stored in the hot water storage tank 57 (residual hot water temperature). And the 1st control means 94 performs the thermal insulation control of a bathtub using the thermal insulation upper limit temperature and the thermal insulation lower limit temperature which changes with remaining hot water temperatures. Here, the remaining hot water temperature in the hot water storage tank 57 is detected by the remaining hot water temperature detection means 86 attached to the upper part of the hot water storage tank 57.

  Fig. 2 shows the changes in the temperature of the bathtub and the remaining hot water when there is no person in the bathroom, with the elapsed time of the heat retention on the horizontal axis and the bathtub temperature and the remaining hot water temperature on the vertical axis. It is. In the figure, the remaining hot water temperature at point A is Ta, and the remaining hot water temperature at point B is Tb (Ta> Tb). In addition, the lower temperature limit for the remaining hot water temperature is TL1a when Ta and TL1b when TL (TL1b> TL1a).

  The bath is heated by the bath heat exchanger 73 between the hot water sent from the bathtub 68 by the use side circulation pump 77 and the hot water at the upper part of the hot water tank 5 sent by the heat source side circulation pump 76. Done. Therefore, the heating capacity of the bathtub differs greatly depending on the temperature of the hot water in the upper part of the hot water tank 5 (remaining hot water temperature) (in the case of the figure, the heating capacity Qa at the remaining hot water temperature Ta and the heating capacity at the remaining hot water temperature Tb). If Qb, then Qa> Qb).

In addition, the following may be considered as behaviors until a person enters the bathroom for bathing and is immersed in the bathtub 68. First, go to the front of the bathtub 68, open the lid of the bathtub 68, pour hot water with the hot water of the bathtub 68, or pour hot water with a shower (not shown) and then immerse in the bathtub 68. It takes a little time (about 20 to 30 seconds) from entering the bathroom 80 to entering the bathtub 68 (t0 in the figure).

  Therefore, during this time, the temperature of the bathtub 68 may be raised to a temperature at which the bathtub 68 does not become uncomfortable (T0 in the figure). Especially when the temperature is low, such as in winter, the body surface temperature is low, so if the temperature of the bathtub 68 is set to the preset temperature when immersed in the bathtub 68, it feels hotter, so it is slightly lower than the set temperature. It feels comfortable to enter the bathtub 68 with eyes. The heat insulation lower limit temperature can be changed by the remaining hot water temperature by the amount of heat that can be heated during this time t0 depending on the remaining hot water temperature.

  Eventually, the heat retention lower limit temperature may be changed in accordance with the difference in the heating capacity depending on the remaining hot water temperature. In general, the heat insulation lower limit temperature may be set so that the bath temperature becomes T0 during the time t0. If it does in this way, it will not become uncomfortable even if the human detection means 81 detects a person and retreats the bathtub 68 at the timing when the bathtub is coldest (when the bathtub temperature is the heat insulation lower limit temperature), Furthermore, the temperature of the bathtub 68 can be kept low compared with the conventional case.

  Next, a case where a person is in the bathroom 80 will be described. First, the upper and lower limit temperature setting means 97 sets a heat retention upper limit temperature that is an upper limit temperature of the control temperature range of the bathtub 68 and a heat retention lower limit temperature that is a lower limit temperature. When a person enters the bathroom 80 in the absence of the person in the bathroom 80, the person is detected by the person detecting means 81 and the bathtub 68 is retreated. Thereafter, while the person is in the bathroom 80, the following heat insulation operation is performed. In this case, the bathtub temperature detection operation is performed every time interval t, and if the bathtub temperature detected by the bathtub temperature detection means 83 is higher than the heat insulation lower limit temperature of the control temperature, the bathtub temperature detection operation is terminated, and the next bathtub temperature detection is performed. Wait until driving.

  On the other hand, if the detected bath temperature is equal to or lower than the heat retention lower limit temperature of the control temperature, the bath reheating operation is performed until the bath temperature reaches the heat retention upper limit temperature of the control temperature. In this case, the heat insulation lower limit temperature and the heat insulation upper limit temperature are respectively constant temperatures because there is a bather in the bathroom 80 and the bath temperature needs to be kept at an appropriate temperature. In addition, what is necessary is just to determine a heat retention minimum temperature and a heat retention upper limit temperature as follows.

  When it is desired to control the temperature change of the bathtub 68 to about 1K, the heat retention upper limit temperature is set to (set temperature + 0.5K) and the heat retention lower limit temperature is set to (set temperature-0) with respect to the set temperature set by the bath temperature setting means 83. .5K). Moreover, when it is desired to control the temperature of the bathtub 68 to about 0.5K, the heat insulation lower limit temperature is set to (set temperature −0.5K) with respect to the set temperature set by the bath temperature setting means 83, and the heat insulation upper limit temperature is set to ( Set temperature).

  Then, the upper and lower limit temperature setting means 97 sets a heat retention upper limit temperature and a heat retention lower limit temperature, which are constant temperatures that are not related to the remaining hot water temperature, and the second control means 95 uses this to set the heat retention upper limit temperature and the heat retention lower limit temperature. Perform heat insulation control.

  Depending on whether the person is not in the bathroom or in the room, the first control means 94 and the second control means 95 may be switched by the control switching means 96 to control the heat insulation operation as follows. FIG. 3 shows changes in the temperature of the bathtub and the remaining hot water with the elapsed time of the heat retention on the horizontal axis and the bath temperature and the remaining hot water temperature at that time on the vertical axis. In the same figure, TU1 is the heat retention upper limit temperature of the first control means 94, and TL1a and TL1b (TL1b> TL1a) are the first control means 94 corresponding to the remaining hot water temperatures Ta and Tb (Ta> Tb), respectively. This is the lower temperature limit.

Further, TU2 is a heat retention upper limit temperature of the second control means 95, and TL2 is a heat retention lower limit temperature of the second control means 95. Further, the heat retention upper limit temperature TU1 of the first control means 94 is a temperature lower than the heat retention upper limit temperature TU2 of the second control means 95 (TU1 <TU2). TL1a and TL1b (TL1b> TL1a) are set to a temperature (TL1a1 <TL1b <TL2) that is lower than the heat retention lower limit temperature TL2 of the second control means 95.

  When a person enters the absent bathroom 80 at the elapsed time X in the figure, the person detecting means 81 detects the person and starts chasing. At this time, the control switching means 96 switches from the first control means 94 to the second control means 95, and performs heat insulation control of the bathtub 68.

  That is, the temperature of the bathtub 68 is controlled to be approximately between the heat retention upper limit temperature TU2 and the heat retention lower limit temperature TL2. Then, when a person is absent in the bathroom 80, the control switching unit 96 switches from the second control unit 95 to the first control unit 94, and performs heat insulation control of the bathtub 68.

  That is, the temperature of the bathtub 68 is controlled so as to be approximately between the heat retention upper limit temperature TU1 and the heat retention lower limit temperature TL1a (at the remaining hot water temperature Ta) or TL1b (at the remaining hot water temperature Tb). If it does in this way, when a person takes a bath, the bathtub temperature can be kept at an appropriate temperature, and when the person is absent, the temperature of the bathtub 68 can be kept low.

  As a result, since heat radiation from the bathtub 68 can be reduced, the heat retention efficiency is improved. Further, since the number of times of reheating can be reduced, the amount of hot water used in the hot water storage tank 57 can be reduced, and the occurrence of running out of hot water can be reduced to improve convenience and comfort.

  In the case of the first control means 94 described above, the heat insulation lower limit temperature has been described in two ways depending on the remaining hot water temperature, but the same effect can be obtained by setting the heat insulation lower limit temperature for three or more remaining hot water temperatures as required. An effect is obtained.

  As described above, the switching means 96 automatically switches between the first control means 94 and the second control means 95 during automatic bath operation, but if the user always prefers a higher bath temperature. In some cases, the control selection means 98 may be provided so that the first control means 94 and the second control means 95 can be manually switched.

  Furthermore, if the control selection means 98 is provided in a bathroom remote controller 87 or a kitchen remote controller (not shown), the convenience is good. As described above, the control selection means 98 selects the second control means 95 when the temperature of the bathtub is always kept at an appropriate temperature state, and the control selection is selected when the heat radiation amount from the bathtub 68 is reduced to save energy. The first control means 94 may be selected by the means 98.

  In addition, when the human detection unit 81 has a poor human detection performance due to a failure or the like, the second control unit 95 is used to control the bath temperature. In this way, the bathtub 68 can be maintained at a desired predetermined temperature regardless of whether or not a person is detected, which is effective in comfort and convenience.

  As described above, the hot water storage type water heater according to the present invention determines the minimum temperature for keeping the bathtub in accordance with the remaining hot water temperature when no one is present. Since the bath temperature can be set, the heat retention efficiency and the comfort can be improved.

The block diagram of the hot water storage type hot water heater in Embodiment 1 of this invention The figure which shows the change of the bathtub temperature at the time of bath chasing operation when the coterie detection means has not detected the presence of a person in the bathroom The figure which shows the change of bathtub temperature at the time of the bath chasing operation when the coterie detection means detects the presence of a person and when the presence of a person is not detected Configuration diagram of a conventional hot water storage water heater The figure which shows change of bathtub temperature at the time of bath automatic operation of the hot water storage type water heater

55 Heating means 57 Hot water storage tank 68 Bathtub 73 Bath heat exchanger 80 Bathroom 81 Person detection means 82 Control means 86 Remaining hot water temperature detection means

Claims (6)

Hot water storage tank for storing hot water, residual hot water temperature detection means for detecting the remaining hot water temperature of the hot water storage tank, heating means for generating high temperature water stored in the hot water storage tank, a bathtub, hot water in the hot water storage tank, and the The human detection includes a bath heat exchanger that heats the hot water in the bathtub by exchanging heat with the hot water in the bathtub, a human detection means that detects the presence of a person in the bathroom, and a control means. When the means does not detect the presence of a person in the bathroom, the start temperature for reheating the hot water in the bathtub by the bath heat exchanger is lower than when the temperature detected by the remaining hot water temperature detecting means is high A hot water storage water heater characterized by setting a higher temperature in the case. The start temperature for reheating the hot water in the bathtub by the bath heat exchanger, which is performed when the human detection means detects the presence of a person, is not changed based on the temperature detected by the remaining hot water temperature detection means. Item 2. A hot water storage type water heater according to item 1. The bath reheating operation stop temperature by the bath heat exchanger performed when the human detection means does not detect the presence of a person is set to be constant regardless of the temperature detected by the remaining hot water temperature detection means. The hot water storage type water heater according to claim 1 or 2 . The bath heat exchanger reheating operation stop temperature by the bath heat exchanger that is performed when the human detection means does not detect the presence of a person is the bath temperature by the bath heat exchanger that is performed when the human detection means detects the presence of a person. The hot-water storage type hot water supply device according to any one of claims 1 to 3, wherein the temperature is set to be lower than a temperature for stopping the reheating operation of hot water. The bath start-up operation temperature of the hot water in the bathtub by the bath heat exchanger performed when the human detection means does not detect the presence of a person is the bathtub temperature by the bath heat exchanger that is performed when the human detection means detects the presence of a person The hot water storage hot water supply apparatus according to any one of claims 1 to 4, wherein the temperature is set to be lower than a start temperature for reheating the hot water. The hot water storage type hot water supply device according to any one of claims 1 to 5 , wherein a heat pump is used as the heating means.

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