JP2013117343A - Heat-pump water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve heating capability of a bath heat exchanger, while preventing a reduction in heating efficiency (COP) in a heat-pump heating means.SOLUTION: The heat-pump water heater includes: a heating bypass pipe 29 branched from a heat-pump return pipe 27 to return hot water to the lower part of a hot water storage tank 1; a switch means 30 for returning the heated hot water to the upper part or the lower part of the hot water storage tank 1; a bath heat exchanger 13 for heating bathtub water; and a control means 39 that starts heating operation when an additional heating start condition is satisfied, and switches the switching means 30 to the upper side of the hot water storage tank 1 when a heating temperature sensor 32 detects a predetermined temperature or higher. A determination means 40 is provided which determines whether the bathtub water is highly likely to be heated or not. When the bathtub water is highly likely to be heated, a predetermined temperature for switching the switching means 30 is set to a predetermined higher temperature.

Description

  The present invention relates to a heat pump water heater that heats hot water in a hot water storage tank by a heat pump heating means.

  Conventionally, in this type of heat pump water heater, as disclosed in Patent Document 1, a heat pump heating means provided with a hot water storage tank for storing hot water and a water refrigerant heat exchanger for heating the hot water in the hot water storage tank. A heat pump forward pipe for allowing hot water in the lower part of the hot water storage tank to flow into the water refrigerant heat exchanger, a heat pump return pipe for returning hot water heated by the water refrigerant heat exchanger to the upper part of the hot water storage tank, and the heat pump return A bypass pipe that branches off from a pipe and returns hot water from the water refrigerant heat exchanger to the lower part of the hot water storage tank, and returns hot water from the water refrigerant heat exchanger to the upper part of the hot water storage tank from the heat pump return pipe or the bypass pipe Switching means for switching whether to return to the lower part of the hot water storage tank, a boiling temperature sensor for detecting the temperature of hot water from the water refrigerant heat exchanger, and hot water in the hot water storage tank A heating circulation pump for circulating to the water refrigerant heat exchanger, the boiling temperature sensor was something and a control means for switching to the hot water storage tank upper side the switching means and for detecting a predetermined temperature or more.

JP 2009-264617 A

  However, in this conventional one, if the predetermined temperature for switching the switching means is set to a high temperature, the water temperature in the low temperature layer below the hot water tank rises at the start of the boiling operation for increasing the amount of hot water in the hot water tank, The heating efficiency (COP) in the heat pump type heating means is lowered.

  On the other hand, when the predetermined temperature for switching the switching means is set to a low temperature, the hot water storage temperature is lowered because the medium-temperature hot water flows into the upper portion of the hot water storage tank at the start of the boiling increase operation. And if the hot water temperature of the hot water storage tank upper part falls, there existed a problem that the heating capability of the bath heat exchanger which heats bathtub water using the hot water of the hot water storage tank upper part as a heat source will fall.

  Then, this invention aims at the improvement of the heating capability of a bath heat exchanger, suppressing the fall of the heating efficiency (COP) in a heat pump type heating means.

  In order to achieve the above object, the present invention provides a hot water storage tank for storing hot water, a heat pump type heating means having a water refrigerant heat exchanger for heating the hot water in the hot water storage tank, and a lower part in the hot water storage tank. A heat pump forward pipe for flowing hot water into the water refrigerant heat exchanger, a heat pump return pipe for returning hot water heated by the water refrigerant heat exchanger to the upper part of the hot water storage tank, and a hot water storage tank branched from the heat pump return pipe A boiling bypass pipe for returning hot water from the water refrigerant heat exchanger to the lower part, and hot water from the water refrigerant heat exchanger is returned from the heat pump return pipe to the upper part of the hot water storage tank or from the boiling bypass pipe to the hot water storage. Switching means for switching back to the lower part of the tank, a boiling temperature sensor for detecting the temperature of hot water from the water-refrigerant heat exchanger, and hot water in the hot water storage tank for the water refrigerant A heating circulation pump that circulates to the exchanger, a hot water filling circuit that fills the bathtub with a predetermined amount or a predetermined water level, a bath heat exchanger that heats the bathtub water using hot water at the top of the hot water storage tank, and the bathtub water A bath circulation pump that circulates to the bath heat exchanger and whether or not the boiling start condition is satisfied, and when the boiling start condition is satisfied, the heat pump heating means and the heating circulation pump are driven to boil And a control means for switching the switching means to the upper side of the hot water storage tank when the boiling temperature sensor detects a temperature equal to or higher than a predetermined temperature, and a heat pump water heater provided with the bath heat exchanger. A determination unit that determines whether the possibility of water heating is high or low is provided, and the control unit heats bath water by the determination unit When potential is determined to be high, and to that so as to change the predetermined temperature for switching the switching means to a higher temperature.

  According to a second aspect of the present invention, the determination means determines that there is a high possibility that the bath water is heated when the filling of the bath is started.

  Moreover, in Claim 3, the water level sensor which detects the water level in the said bathtub is provided, and when the said water level sensor has detected the presence of bathtub water, the said determination means may heat bathtub water. Judged to be high.

  Moreover, in Claim 4, while the said determination means is performing bath heat insulation control which controls the action | operation of the said bath circulation pump and heats bath water so that the bath water may be kept at desired temperature for a predetermined time. It was determined that there was a high possibility that the bath water would be heated.

  Moreover, in Claim 5, when the said determination means performed the heating operation of bathtub water, it was considered that possibility of heating of bathtub water was high.

  According to a sixth aspect of the present invention, bathing detection means for detecting bathing in the bathtub is provided, and the determination means determines that the bath water is likely to be heated when the bathing detection means detects a bather. I did it.

  Moreover, in Claim 7, in the thing of any one of the said Claims 2-6, the said determination means memorize | stores the presence or absence of the heating performance of the bath water of the past predetermined period, and has memorize | stored the heating performance presence. Only in the case, it was determined that there was a high possibility that the bath water was heated.

  According to the present invention, since the predetermined temperature for switching the switching means is set high when there is a high possibility that the bath water is heated, the boiling water is heated during the boiling operation when there is a high possibility that the bath water is heated. When the temperature of the hot water returning to the upper part of the hot water tank rises at the beginning of the raising operation, the heating capacity of the bath heat exchanger can be improved and the bath water is not likely to be heated. Since the temperature of the hot water returning to the lower part of the hot water tank at the start of the boiling operation of the water becomes relatively low, the temperature rise of the low temperature layer at the lower part of the hot water tank is suppressed, and the heating efficiency (COP) in the heat pump heating means is improved. It is something that can be done.

Schematic configuration diagram of one embodiment of the present invention Flow chart for explaining the operation of the same embodiment

Next, an embodiment of the present invention will be described with reference to the drawings.
1 is a stainless steel hot water storage tank for storing hot water, 2 is a water supply pipe for supplying city water to the bottom of the hot water storage tank 1, 3 is a hot water discharge pipe for discharging hot water from the top of the hot water storage tank 1, 4 is a water supply bypass branched from the water supply pipe 2 A hot water mixing valve that mixes hot water from the hot water discharge pipe 3 and water from the hot water supply bypass pipe 4 so as to reach a hot water supply set temperature, 6 is a hot water supply pipe through which hot water mixed by the hot water mixing valve 5 flows, 7 is a hot-water tap for supplying hot water from the hot-water supply pipe 6, 8 is a hot-water supply temperature sensor for detecting the hot-water supply temperature provided in the middle of the hot-water supply pipe 6, and 9 is a hot-water supply flow rate sensor for detecting the amount of hot water provided in the middle of the hot-water supply pipe 6. A pressure reducing valve 10 is provided in the water supply pipe 2 to reduce the supply pressure of city water to a constant pressure, and 11 is an overpressure relief valve for releasing the overpressure in the hot water storage tank 1.

  12 is a bath, 13 is a bath heat exchanger provided at the upper part of the hot water storage tank 1 for heating the bath water with the heat of the hot water in the hot water storage tank 1, and 14 is a bath water for the bath 12 and the bath heat exchanger 13. The bath circulation circuit 15 is connected so as to be circulated, the bath circulation pump 15 is provided in the middle of the bath circulation circuit 14 and circulates the bath water, the hot water filling circuit 16 is branched from the hot water supply pipe 6 and connected to the bath circulation circuit 14, 17 Is a hot water on / off valve provided in the middle of the hot water circuit 16 and opens and closes the hot water circuit 16, and 18 is a bath temperature which is provided in the middle of the bath circulation circuit 14 and detects the temperature of the bath water flowing from the bathtub 12 to the bath heat exchanger 13. A sensor 19 is provided in the bath circulation circuit 14 and is a water level sensor for detecting the water level of the bathtub water in the bathtub 12. Here, the bath heat exchanger 13 has a configuration in which a stainless steel tube is spirally wound.

  20 is a heat pump heating means, a compressor 21 for compressing refrigerant, a water refrigerant heat exchanger 22 for exchanging heat between the refrigerant and water, a decompressor 23 for reducing the pressure of the refrigerant, and evaporation for evaporating the liquid refrigerant. An air heat exchanger 24 as a heat exchanger and a blower means 25 for blowing air to the air heat exchanger 24, and the refrigerant that has absorbed heat by the air heat exchanger 24 is compressed by the compressor 21 through the water refrigerant heat exchanger 22. The water is heated. This heat pump type heating means 20 uses carbon dioxide refrigerant as the refrigerant, and can heat water to a high temperature of 90 ° C. when the high-pressure side is in a supercritical state.

  Reference numeral 26 denotes a heat pump forward pipe for connecting hot water to the lower part of the hot water storage tank 1 and the inlet side of the water refrigerant heat exchanger 22, and 27 denotes hot water between the outlet side of the water refrigerant heat exchanger 22 and the upper part of the hot water storage tank 1. , A heating circulation pump provided in the middle of the heat pump return pipe 26, 29 a heating bypass pipe branched in the middle of the heat pump return pipe 27 and connected to the lower part of the hot water storage tank 1, 30 is a switching comprising a three-way valve for switching whether the hot water heated by the water-refrigerant heat exchanger 22 is returned to the upper part of the hot water storage tank 1 via the heat pump return pipe 27 or returned to the lower part of the hot water storage tank 1 via the boiling bypass pipe 29 Means.

  31 is a water temperature sensor that detects the temperature of water flowing into the water refrigerant heat exchanger 22, 32 is a boiling temperature sensor that detects the temperature of hot water heated by the water refrigerant heat exchanger 22, and 33 is a hot water storage tank 1. A plurality of hot water storage temperature sensors provided in the vertical direction of the side surface are used to detect the temperature of hot water in the hot water storage tank 1, and are referred to as 33a, 33b, 33c, 33d, 33e, and 33f from the top.

  34 is a remote controller for operating the heat pump water heater, and a display unit 35 for displaying various information related to the water heater (hot water set temperature, bath set temperature, amount of hot water in the hot water storage tank, operating state of the water heater, etc.) A set value operation switch 36 for setting and operating the hot water supply set temperature, bath set temperature and bathtub water level, and a bath automatic switch 37 for instructing the bathtub 12 to automatically keep the bath water for a predetermined time following a certain amount of hot water filling And a reheating switch 38 for instructing reheating of the bathtub water.

  39 is a hot water supply temperature sensor 8, a hot water supply flow rate sensor 9, a bath temperature sensor 18, a water level sensor 19, an incoming water temperature sensor 31, a boiling temperature sensor 32, and hot water storage temperature sensors 33 a to 33 f. Control means for controlling the operation of the bath circulation pump 15, the hot water on-off valve 17, the compressor 21, the decompressor 23, the air blowing means 25, the heating circulation pump 28, and the switching means 30, and control means connected to the remote controller 33 so as to be communicable is there.

  And this control means 39 is based on the program memorize | stored beforehand, the hot water supply preset temperature set with the remote controller 34, the hot water supply temperature estimated from the lowest temperature detected by the lowest hot water storage temperature sensor 33f, and hot water supply flow rate The amount of hot water supplied to the outside from the hot water storage tank 1 per day is calculated from the hot water flow rate detected by the sensor 9, and the target boiling temperature of the hot water heated by the heat pump heating means 20 is determined based on the amount of hot water discharged until the previous day. Then, it is determined whether the boiling start condition is satisfied based on the amount of remaining hot water in the hot water storage tank 1 detected by the hot water storage temperature sensors 33a to 33f, and the boiling temperature sensor 32 reaches the target boiling temperature at the start of boiling. When a predetermined temperature or more determined based on the detected temperature is detected, the switching means 30 is switched from the hot water storage tank 1 lower side to the hot water storage tank 1 upper side, In which the end condition boiling based on the remaining hot water and the like in the hot water storage tank 1 for detecting is adapted to determine whether filled with 3A～f.

Moreover, the control means 39 is provided with the determination means 40 which determines whether the possibility that the bath water using the bath heat exchanger 13 is heated is high or low. In any case, it is determined or considered that the possibility that the bath water is heated is high.
(1) The bath automatic switch 37 of the remote controller 34 is operated, and hot water filling to the bathtub 12 is started via the hot water filling circuit 16.
(2) A case where the water level sensor 19 detects a state in which there is bathtub water by detecting a predetermined water level or higher.
(3) The bath automatic switch 37 of the remote controller 34 is operated, and the bath temperature control is performed to heat the bath water by intermittently controlling the bath circulation pump 15 so as to keep the bath water at a desired temperature for a predetermined time. While you are.
(4) When the reheating switch 38 of the remote controller 34 is operated and the bath circulation pump 15 is driven to heat the bath water.
(5) When the water level sensor 19 as a bathing detection means for detecting bathing in the bathtub detects a rise in the water level and detects a bather. In addition, as a bathing detection means, it is good also as what discriminate | determines whether the bather entered the bathroom by not only the water level sensor 19 but an infrared sensor etc.

  Furthermore, the determination means 40 memorize | stores the presence or absence of the heating performance of the bath water using the bath heat exchanger 12 during the past predetermined period (here 7 days), and the state with the heating performance of bath water stored In addition, more reliable determination may be performed by determining that there is a high possibility that the bath water is heated in any of the cases (1) to (5).

  Next, the hot water supply operation will be described. When the hot water tap 7 is opened, city water flows into the bottom of the hot water storage tank 1 from the water supply pipe 2 and hot water is discharged from the top of the hot water storage tank 1 through the hot water discharge pipe 3. Then, the control means 39 adjusts the opening of the hot water mixing valve 5 so that the hot water temperature detected by the hot water temperature sensor 8 becomes the hot water set temperature set by the set value operation switch 36 of the remote controller 34, and from the hot water tap 7. The hot water supply operation is completed when hot water at the hot water supply set temperature is supplied and the hot water tap 7 is closed.

  During this hot water supply, the water flowing into the bottom of the hot water storage tank 1 is sufficiently decelerated in the hot water storage tank 1 having a sufficiently large cross-sectional area compared to the cross-sectional area of the water supply pipe 2, and hardly disturbs the hot water layer. A layer of water is formed from below. And the temperature boundary layer which the hot water of the hot water storage tank 1 upper part and the low temperature water of the hot water storage tank 1 lower part contact is formed. As the amount of hot water increases, the hot water layer at the upper part of the hot water storage tank 1 decreases and the water layer at the lower part of the hot water storage tank 1 increases to raise the temperature boundary layer. If there is a predetermined temperature difference, this temperature boundary layer does not mix due to the difference in specific gravity based on the respective temperatures.

  Next, the hot water filling operation will be described. When the automatic bath switch 37 of the remote controller 34 is operated, the control means 39 opens the hot water filling on / off valve 17 so that the hot water temperature detected by the hot water temperature sensor 8 is the remote controller 34. The set value operation switch 36 is used to adjust the opening of the hot water supply mixing valve 5 so as to reach the bath set temperature, to fill the appropriate temperature hot water via the hot water filling circuit 16 and the bath circulation circuit 14, and the hot water flow rate. When the sensor 9 accumulates the desired hot water filling flow rate, the hot water on / off valve 17 is closed to end the hot water filling operation.

  And the heat retention operation | movement which keeps the temperature of bathtub water at bath preset temperature is performed for the predetermined time after the hot-water filling operation | movement was complete | finished. The heat retaining operation will be described. The control means 39 drives the bath circulation pump 15 at predetermined intervals to circulate the bath water in the bath circulation circuit 14 and detects the temperature of the bath water with the bath temperature sensor 18. When the temperature of the bath water is lower than the bath set temperature, the bath circulation pump 15 is continuously driven to absorb the heat of the hot water in the hot water storage tank 1 from the bath heat exchanger 13 to heat the bath water. When the temperature detected by the bath temperature sensor 18 detects the bath set temperature, the operation of the bath circulation pump 15 is terminated, and the same operation is repeated when the interval time elapses again. Then, when the predetermined time is finished, the heat retaining operation is finished.

  Further, the reheating operation when the reheating switch 38 of the remote controller 34 is operated will be described. The control means 39 is configured to retreat the bath water temperature to a bath set temperature + a constant temperature (for example, 2 ° C.). The bath circulation pump 15 is driven, the bath water is circulated to the bath heat exchanger 13, and the bath water is heated by absorbing the heat of the hot water in the hot water storage tank 1 from the bath heat exchanger 13. When the temperature detected by the bath temperature sensor 18 detects the bath set temperature + the constant temperature, the driving of the bath circulation pump 15 is terminated and the reheating operation is terminated.

Next, the heating operation in the midnight time zone will be described with reference to the flowchart of FIG.
When the control means 39 recognizes that the electricity unit price is cheap, it is calculated that the amount of discharged hot water, the amount of remaining hot water in the hot water storage tank 1 detected by the hot water storage temperature sensors 33a to 33f, and the hot water storage at the bottom. Based on the feed water temperature detected by the temperature sensor 33f, the temporary boiling temperature in the midnight time zone is calculated from the following formula, and the calculated temperature is rounded up to 5 ° C. to determine the target boiling temperature.

Boiling target temperature = {(heat output amount-remaining hot water amount) / (tank capacity-remaining hot water amount)} + feed water temperature

Here, the tank capacity uses a predetermined value based on the capacity of the hot water storage tank 1 (here, a value obtained by subtracting the minimum hot water storage capacity to be secured from the capacity of the hot water storage tank 1 until the start of the midnight time zone). The remaining hot water amount is detected by the hot water storage temperature sensors 33a to 33f from the distribution state of hot water at a predetermined temperature (for example, 50 ° C.) or higher where reheating by the heat pump heating means 20 is difficult.

  The control means 39 then heats up the amount of heat necessary for the next day before the end time of the midnight time zone from the amount of hot water to be boiled (tank capacity-remaining hot water amount), the target boiling temperature, and the rated heating capacity of the heat pump heating means 20. The boiling start time is calculated by peak shift calculation, and when the current time reaches the boiling start time (Yes in step S1 because the boiling start condition is satisfied), the compressor 21, the decompressor 23, the blower 25, and the heating The circulation pump 28 is driven and controlled, and hot water taken out from the lower part of the hot water storage tank 1 through the heat pump forward pipe 26 is heated by the water / refrigerant heat exchanger 22 to start a boiling operation (step S2). Return to the lower part of the hot water storage tank 1 from the raising bypass pipe 29.

  In the subsequent step S3, the determination means 40 determines whether or not the bath water is likely to be heated. Here, since it is a midnight time zone, none of the above conditions (1) to (5) is satisfied. Therefore, it becomes No in step S3 and proceeds to step S5, and the control means 39 has a boiling temperature detected by the boiling temperature sensor 32 that is lower than the predetermined temperature at which the bath water is heated at a predetermined temperature at which the switching means 30 is switched. It changes to 1st predetermined temperature (here target boiling temperature -15 degreeC), and it is judged whether this 1st predetermined temperature was continuously detected for 10 seconds or more.

  Then, when the heating operation of the heat pump type heating means 20 is started and the boiling temperature continues to be higher than the first predetermined temperature, Yes is made in step S5, and the control means 39 moves the switching means 30 to the upper side of the hot water tank 1. The hot water heated by the water refrigerant heat exchanger 22 is returned to the upper part of the hot water storage tank 1.

  Then, when the boiling operation proceeds and the necessary amount of heat is heated up the next day and the completion condition of the boiling operation is satisfied, the boiling operation is terminated (steps S7 to S8). Here, the end condition is, for example, when the hot water storage temperature sensor 33f at the bottom of the hot water storage tank 1 detects a predetermined temperature, when the end time of the midnight time zone is reached, or the water temperature sensor 31 of the heat pump heating means 20 , It is determined that the termination condition is satisfied when a predetermined water inlet upper limit temperature (for example, 50 ° C.) is detected.

Next, the heating operation in the daytime time zone will be described with reference to the flowchart of FIG.
When the control means 39 determines that the boiling start condition is satisfied due to a decrease in the amount of remaining hot water accompanying the hot water supply or a decrease in the hot water storage temperature accompanying the reheating of the bath water (Yes in step S1), the compressor 21 and the decompressor 23 Then, the blower 25 and the heating circulation pump 28 are driven and controlled, and the hot water taken out from the lower part of the hot water storage tank 1 through the heat pump forward pipe 26 is heated by the water refrigerant heat exchanger 22 to start the boiling operation (step S2). Then, the heated hot water is boiled and returned from the bypass pipe 29 to the lower part of the hot water storage tank 1.

  In subsequent step S3, the determination means 40 determines whether or not the possibility of heating the bath water is high. If any of the above conditions (1) to (5) is satisfied, Yes in step S3. Then, the process proceeds to step S4, where the control means 39 sets the predetermined temperature at which the boiling temperature detected by the boiling temperature sensor 32 switches the switching means 30 to a second predetermined temperature (here, higher than the possibility of heating the bath water). Then, it is determined whether the second predetermined temperature has been detected continuously for 10 seconds or more.

  Then, when the heating operation of the heat pump type heating means 20 starts up and the boiling temperature continues to be higher than the second predetermined temperature, the control means 39 brings the switching means 30 to the upper side of the hot water storage tank 1 in step S4. The hot water heated by the water refrigerant heat exchanger 22 is returned to the upper part of the hot water storage tank 1.

  The boiling operation ends when the boiling operation finishes and the time from the start of the boiling operation reaches the upper limit time or the heating operation end conditions such as whether the amount of heat necessary for the day has been completed are satisfied. (Steps S7 to S8). In addition to the above, the end condition is, for example, when the hot water storage temperature sensor 33f at the bottom of the hot water storage tank 1 detects a predetermined temperature, or when the incoming water temperature sensor 31 of the heat pump heating means 20 has a predetermined incoming water upper limit temperature. When (for example, 50 ° C.) is detected, it is determined that the end condition is satisfied.

  On the other hand, if it is determined in step S3 that the determination means 40 does not satisfy any of the above conditions (1) to (5) and the possibility of heating the bath water is low, the result is No in step S3 and the process proceeds to step S5. The control unit 39 sets the predetermined temperature at which the boiling temperature detected by the boiling temperature sensor 32 switches the switching unit 30 to a first predetermined temperature (in this case, the target boiling temperature, which is lower than when the bath water is highly likely to be heated). -15 ° C.), and it is determined whether or not the first predetermined temperature is detected continuously for 10 seconds or more.

  Thus, when the possibility of heating bath water is high, when the heating operation of the heat pump heating means 20 at the start of boiling up to the second predetermined temperature or higher, which is higher than when the possibility is low, starts up In order to switch the switching means 30 and return the hot water from the water / refrigerant heat exchanger 22 to the upper part of the hot water storage tank 1, bath heat exchange is performed in order to suppress a decrease in the temperature of the hot water serving as the heat source of the bath heat exchanger 13 in the upper part of the hot water storage tank 1. When the possibility of heating the bath water is low and the possibility of heating the bath water is low, the heat pump at the start of boiling up to the first predetermined temperature or higher, which is a lower temperature than the case where the possibility is high When the heating operation of the heating means 20 is started, the switching means 30 is switched to return the hot water from the water / refrigerant heat exchanger 22 to the upper part of the hot water tank 1, so that the temperature of hot water returning to the lower part of the hot water tank 1 is changed. Because but relatively low, in which it is possible to suppress the temperature rise of the hot water storage tank 1 lower cold layer, to improve the heating efficiency of the heat pump type heating unit 20 (COP).

  Therefore, the second predetermined temperature is set to a higher temperature than in the prior art with emphasis on the heating capacity of the bath water, and the first predetermined temperature is a lower temperature than in the past with an emphasis on the heating efficiency (COP) of the heat pump heating means 20. It is possible to improve both the heating capacity of the bathtub water and the heating efficiency (COP) of the heat pump heating means 20.

  The present invention is not limited to the above-described embodiment, and can be modified without changing the gist of the invention. For example, the timing for changing the predetermined temperature for switching the switching means 30 is actually changed. It is good also as the timing which the determination means 40 determined that the possibility of heating of bath water is high instead of the timing which starts a boiling operation, and without providing the bath heat exchanger 13 in the hot water storage tank 1, it is the primary side. The heat exchanger of the type that exchanges heat with the secondary side is adopted and placed outside the hot water storage tank 1, taken out from the upper part of the hot water storage tank 1 and distributed to the primary side of this heat exchanger, the secondary of this heat exchanger You may make it heat-exchange with the bathtub water which distribute | circulates to the side.

  Further, the first predetermined temperature and the second predetermined temperature for switching the switching means 30 have been described as values based on the target boiling temperature. However, the present invention is not limited to this. For example, the first predetermined temperature is 50 ° C., and the second predetermined temperature is 60. The temperature may be fixed at 0 ° C., respectively, as long as the relationship of the first predetermined temperature <the second predetermined temperature is satisfied.

DESCRIPTION OF SYMBOLS 1 Hot water storage tank 13 Bath heat exchanger 15 Bath circulation pump 16 Hot water filling circuit 19 Water level sensor 20 Heat pump type heating means 26 Heaton forward pipe 27 Heaton return pipe 28 Heating circulation pump 29 Boiling bypass pipe 30 Switching means 32 Boiling temperature sensor 39 Control means 40 determination means

Claims (7)

  A hot water storage tank for storing hot water, a heat pump type heating means provided with a water refrigerant heat exchanger for heating the hot water in the hot water storage tank, and a heat pump going to flow the hot water in the lower part of the hot water storage tank into the water refrigerant heat exchanger A pipe, a heat pump return pipe for returning hot water heated by the water refrigerant heat exchanger to the upper part of the hot water storage tank, and a boiling branch for returning hot water from the water refrigerant heat exchanger to the lower part of the hot water storage tank branched from the heat pump return pipe. And a switching means for switching between returning the hot water from the water-refrigerant heat exchanger from the heat pump return pipe to the upper part of the hot water storage tank or returning from the boiling bypass pipe to the lower part of the hot water storage tank, and the water refrigerant A boiling temperature sensor that detects the temperature of hot water from the heat exchanger, a heating circulation pump that circulates hot water in the hot water storage tank to the water refrigerant heat exchanger, and a bathtub A hot water filling circuit that performs constant or predetermined water level filling, a bath heat exchanger that heats the bath water using hot water at the top of the hot water storage tank, and a bath circulation pump that circulates the bath water to the bath heat exchanger; It is determined whether or not the boiling start condition is satisfied. When the boiling increase start condition is satisfied, the heating pump and the heating circulation pump are driven to start the boiling operation, and the boiling temperature sensor is set to a predetermined value. In a heat pump water heater provided with a control means for switching the switching means to the upper side of the hot water storage tank when detecting a temperature or higher, whether the bath water is heated using the bath heat exchanger is high or low Determining means for determining whether the heating of the bath water is likely to be performed by the determining means. The heat pump water heater, characterized in that so as to change the predetermined temperature to a high temperature to change.   2. The heat pump water heater according to claim 1, wherein the determination means determines that the bath water is likely to be heated when hot water filling to the bathtub is started.   A water level sensor for detecting the water level in the bathtub is provided, and when the water level sensor detects the presence of bath water, the determination means determines that the bath water is likely to be heated. The heat pump water heater according to claim 1.   The determination means controls the operation of the bath circulation pump so as to keep the bath water at a desired temperature for a predetermined time, and bath water is heated while bath heat control is performed to heat the bath water. 2. The heat pump water heater according to claim 1, wherein it is determined that the possibility is high.   2. The heat pump water heater according to claim 1, wherein, when performing the heating operation of the bath water, the determination unit considers that the bath water is likely to be heated.   Bath detection means for detecting bathing in a bathtub is provided, and the determination means determines that the bath water is likely to be heated when the bath detection means detects a bather. The heat pump water heater according to claim 1.   The determination means stores the presence / absence of heating results of bath water for a predetermined period in the past, and can determine that it is highly possible that heating of bath water is performed only when there is a record of heating results. The heat pump water heater according to any one of claims 2 to 6, wherein

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