JP6734450B2 - Heat pump water heater - Google Patents

Description

TECHNICAL FIELD The present invention relates to a heat pump hot water supply apparatus that boils hot water by a heat pump heating means and stores the hot water.

Conventionally, in this type of heat pump type hot water supply device, the water refrigerant heat exchanger of the heat pump type heating means heats the water supplied from the lower part of the hot water storage tank to the target boiling temperature. It has a bypass switching valve that switches between returning the heated water to the upper part of the hot water storage tank or to the lower part of the hot water storage tank.At the start of boiling, the temperature of the boiled water flowing out of the water-refrigerant heat exchanger is the temperature. The boiling water is returned to the lower part of the hot water storage tank until the boiling temperature reaches the predetermined switching temperature, and when the boiling temperature exceeds the predetermined switching temperature, the boiling water is returned to the upper part of the hot water storage tank. By switching the switching valve, it is possible to prevent the low temperature hot water at the start of boiling from flowing into the upper part of the hot water storage tank and lowering the temperature of the upper part of the hot water storage tank.

The predetermined switching temperature for switching the bypass switching valve is determined based on the hot water storage temperature in the upper part of the hot water storage tank as disclosed in Patent Document 1, and the bypass switching is performed when the boiling temperature becomes equal to or higher than the hot water storage temperature in the upper hot water storage tank. There was one that switched the valve to the upper side of the hot water storage tank.

Further, as disclosed in Patent Document 2, a predetermined switching temperature for switching the bypass switching valve is set according to the target boiling temperature, and there is a case where a higher target boiling temperature is set to a higher temperature. ..

JP, 2003-279136, A JP, 2009-264617, A

However, in the conventional Patent Document 1, since the medium to high temperature hot water returns to the lower part of the hot water storage tank until the bypass switching valve is switched, the decrease in the hot water storage temperature at the upper part of the hot water storage tank is suppressed, but at the lower part of the hot water storage tank. There is a problem that the hot water storage temperature rises and the boiling efficiency of the heat pump heating means decreases.

Here, in a usage situation where a relatively small amount of hot water is used in a stable manner, it is considered that hot water supply is being performed with energy saving in mind, so rather than a decrease in the hot water storage amount due to a decrease in the hot water storage temperature at the top of the hot water storage tank, The problem is that the boiling efficiency of the heat pump type heating means is reduced.

On the other hand, in the conventional Patent Document 2, if the target boiling temperature is low (for example, 70° C.), the predetermined temperature for switching the bypass switching valve is set to a lower temperature (for example, 50° C.) than when the target boiling temperature is high. Although the rise of the hot water storage temperature in the lower part of the hot water storage tank is suppressed, the hot water temperature in the upper part of the hot water storage tank may be lowered when hot water having a relatively high temperature (for example, 60° C.) remains in the upper hot water storage tank. ..

Here, in a usage situation in which the amount of hot water used on a daily basis fluctuates greatly, it is possible that the user does not supply hot water in consideration of energy saving, so rather than lowering the boiling efficiency of the heat pump type heating means, It is more problematic that the temperature of the hot water in the tank drops and the hot water runs out.

As described above, in the heat pump type hot water supply device, there are situations where it is not desirable to lower the temperature of the upper part of the hot water storage tank and situations where it is not desirable to raise the temperature of the lower part of the hot water storage tank. I could only deal with it.

In order to solve the above problems, the present invention connects a hot water storage tank for storing hot water, a heat pump type heating means for heating hot water in the hot water storage tank, a lower portion of the hot water storage tank and an inlet side of the heat pump type heating means. A heating return pipe, a heating return pipe connecting the outlet side of the heat pump type heating means and the upper part of the hot water storage tank, a branch pipe branched from the heating return pipe and connected to the lower part of the hot water storage tank, and the heat pump Switching means for switching between returning the hot water from the heating means to the upper part of the hot water storage tank or to returning to the lower part of the hot water storage tank via the branch pipe, and boiling for detecting the temperature of the hot water heated by the heat pump heating means. Raising temperature sensor and switching control means for switching the switching means from the lower side of the hot water storage tank to the upper side of the hot water storage tank when the temperature detected by the boiling temperature sensor becomes equal to or higher than a predetermined switching temperature, and use for the past several days The hot water amount storage means for storing the hot water amount for each day, and the use situation determination means for calculating the value of the variation degree of the hot water amount used based on the information stored in the hot water amount storage means, the switching control means, When the value of the variation degree calculated by the usage status determining means is less than a predetermined value, the predetermined switching temperature is determined to be a lower temperature than when the value of the variation degree is a predetermined value or more. ..

Further, the usage status determining means determines whether or not the maximum value of the amount of hot water used exceeds a predetermined amount, and the switching control means determines that the value of the degree of variation is less than a predetermined value and the maximum value of the amount of hot water used is When the value does not exceed the fixed amount, the predetermined switching temperature is determined to be lower than when the value of the variation degree is equal to or more than the predetermined value and when the maximum value of the amount of hot water used exceeds the predetermined amount.

In addition, a heat exchanger using the hot water in the hot water tank as a heat source to heat bath water or heating circulating water, and a value indicating the usage record of the heat exchanger for the past several days on a daily basis. If the value of the variation degree is less than a predetermined value and the value representing the usage record stored in the heat exchange usage record storage section is less than a predetermined value, the variation degree is provided with the result storage means. The predetermined switching temperature is determined to be lower than the case where the value of is greater than or equal to a predetermined value and the case where the value representing the usage record stored in the heat exchange usage record storage means is equal to or larger than the predetermined value.

Further, the usage status determining means determines whether or not the maximum value of the amount of hot water used exceeds a predetermined amount, and the switching control means determines that the value of the variation degree is less than a predetermined value and the heat exchange usage record storage means. When the value representing the usage record stored in is less than a predetermined value and the maximum value of the amount of hot water used does not exceed the predetermined amount, the value of the degree of variation is greater than or equal to a predetermined value and is stored in the heat exchange usage record storage means. The predetermined switching temperature is determined to be lower than when the value representing the actual usage is equal to or more than the predetermined value and when the maximum value of the amount of hot water used exceeds the predetermined amount.

According to the present invention, the predetermined switching temperature according to the usage status is determined according to the usage status determination result based on the amount of hot water used, so that in the usage status where it is not desired to lower the temperature of the hot water storage tank, the predetermined switching temperature is determined. In a usage situation where it is not desirable to raise the switching temperature to suppress the temperature drop in the upper part of the hot water storage tank or to raise the temperature in the lower part of the hot water storage tank, lower the predetermined switching temperature to suppress the temperature rise in the lower part of the hot water storage tank It is possible to suppress a decrease in heating efficiency of the heating means, and it is possible to perform an efficient operation according to the usage situation.

Schematic configuration diagram of an embodiment of the present invention Control block diagram of the same embodiment Flowchart for explaining the operation of the same embodiment Control block diagram of another embodiment Flowchart for explaining the operation of another embodiment

Next, a heat pump type hot water supply apparatus according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view showing the structure of a bath water heater, 1 is a hot water storage tank for storing hot water, 2 is a water supply pipe for supplying water to the bottom of the hot water storage tank 1, 3 is a hot water supply pipe for discharging hot water from the top of the hot water storage tank 1, 4 is water supply A hot water supply bypass pipe branched from the pipe 2 is a hot water supply mixing valve for mixing hot water from the hot water supply pipe 3 with water from the hot water supply bypass pipe 4, and 6 is an outlet of the hot water supply mixing valve 5 and a hot water tap 7. A hot water supply pipe, 8 is a hot water supply flow rate sensor that detects the flow rate of hot and cold water flowing through the hot water supply pipe 6, 9 is a hot water supply temperature sensor that detects the temperature of hot water flowing through the hot water supply pipe 6, and 10 is the temperature of hot water that flows through the hot water supply bypass pipe 4. It is a feed water temperature sensor.

Reference numeral 11 is a bath mixing valve for mixing hot water from the hot water outlet pipe 3 with water from the water supply bypass pipe 4, and 12 is a filling pipe for filling hot water from the bath mixing valve 11 into a bathtub 13 installed in the bathroom. , 14 is a water filling flow rate sensor that detects the flow rate of the hot water flowing through the water filling pipe 12, 15 is a water filling temperature sensor that detects the temperature of the hot water flowing through the water filling pipe 12, and 16 is a flow path of the water filling pipe 12. A hot water filling solenoid valve, 17 is a hot water storage temperature sensor that is provided on the upper and lower sides of the hot water storage tank 1 to detect the hot water storage temperature.

Reference numeral 18 denotes a stainless steel corrugated pipe arranged in the hot water storage tank 1, and a bath heat exchanger as a use side heat exchanger for heating an external load such as bath water in the bath 13; A bath circulation circuit that connects the bath heat exchanger 18 with the bath water so that the bath water can circulate, and a bath circulation pump 20 that sucks the bath water in the bath 13 and pumps it to the bath heat exchanger 18 to circulate the bath water. Reference numeral 21 denotes a bath heat exchange bypass pipe for connecting the going and returning of the bath circulation circuit 19, and 22 denotes switching between a state in which the bath water returning from the bathtub 13 flows in the bath heat exchanger 18 and a state in which the bath heat exchange bypass pipe 21 flows. A bath three-way valve, 23 is a bath temperature sensor for detecting the temperature of bath water, and 24 is a water level sensor for detecting the water level in the bathtub 13 by detecting the water pressure. 12 are connected.

Reference numeral 25 is a heat pump type heating means for heating hot water in the hot water storage tank 1, 26 is a heating outflow pipe connecting the lower part of the hot water storage tank 1 and the inlet side of the heat pump type heating means 25, and 27 is an outlet of the heat pump type heating means 25. Side is connected to the upper side of the hot water storage tank 1, 28 is a heating circulation pump provided in the middle of the heating forward pipe 26 for circulating hot water, and 29 is branched from the heating return pipe 27 and connected to the lower part of the hot water storage tank 1. A branch pipe, 30 is a switching unit for switching between returning hot water from the heat pump heating means 25 to the upper part of the hot water storage tank 1 or returning to the lower part of the hot water storage tank 1 via the branch pipe 29, and 31 enters the heat pump heating device 25. An inlet temperature sensor for detecting the temperature of hot water, and 32 is a boiling temperature sensor for detecting the temperature of hot water boiled by the heat pump heating means 23.

Here, the heat pump type heating means 25 includes a compressor 33 for compressing a refrigerant such as CO2, a water-refrigerant heat exchanger 34 for exchanging heat between the hot water from the hot water storage tank 1 and the refrigerant, and an expansion valve for expanding and decompressing the radiated refrigerant. 35, an air heat exchanger 36 for exchanging heat between the low temperature and low pressure refrigerant and the outside air, a blower 37 for blowing the outside air to the air heat exchanger 36, and an outside air temperature sensor 38 for detecting the outside air temperature.

Reference numeral 39 denotes a remote controller of the hot water supply device, a display unit 40 for displaying the operating state and setting state of the hot water supply device, a bath switch 41 for starting the automatic hot water filling operation and the automatic warming operation in the bathtub 13, and the hot water supply set temperature. And a change switch 42 for changing the bath set temperature.

Reference numeral 43 is a control means for controlling the operation of the hot water supply apparatus, which is a hot water supply flow rate sensor 8, a hot water supply temperature sensor 9, a water supply temperature sensor 10, a hot water flow sensor 14, a hot water temperature sensor 15, a hot water storage temperature sensor 17, a bath temperature sensor 23. , The water level sensor 24, the incoming water temperature sensor 31, the boiling temperature sensor 32, the outside air temperature sensor 38 are input, and the hot water mixing valve 5, the bath mixing valve 11, the filling solenoid valve 16, the bath circulation pump 20, the bath three-way It controls the operation of the valve 22, the heating circulation pump 28, the switching unit 30, the compressor 33, the expansion valve 35, and the blower 37, and is connected to the remote controller 39 so that necessary information can be transmitted and received. Here, the control means 43 has a logic circuit such as an MPU and controls the operation according to a program stored in advance while referring to the memory.

Next, a control block diagram of the embodiment of the present invention shown in FIG. 2 will be described.

44 is a hot water amount storage means for calculating the hot water amount converted into a predetermined temperature based on the hot water flow rate detected by the hot water flow rate sensor 8 and storing the hot water amount for the past plural days (for example, 7 days) for each day. Here, the hot water supply amount detected by the hot water supply flow rate sensor 8, the hot water supply temperature detected by the hot water supply temperature sensor 9, and the water supply temperature detected by the water supply temperature sensor 10 are used to calculate the amount of hot water used in terms of a predetermined temperature. The hot water supply set temperature may be used instead of the hot water supply temperature, or the lowest temperature of the previous day detected by the hot water storage temperature sensor 17 at the lowermost part may be used instead of the hot water supply temperature.

Reference numeral 45 is a usage status judging means for judging, based on the daily hot water usage information stored in the hot water usage storage means 44, whether the usage status gives priority to boiling efficiency or the usage status giving priority to securing hot water. Is. Here, the usage status determining means 45 calculates the value of the degree of variation of the daily hot water amount stored in the hot water amount storage means 44, and raises when the value of the degree of variation is less than a predetermined value. It is determined that the usage situation is such that priority is given to efficiency, and if the value of the degree of variation is equal to or greater than a predetermined value, the usage situation is given priority to securing high-temperature hot water.

When the temperature detected by the boiling temperature sensor 32 becomes equal to or higher than a predetermined switching temperature 46, the switching means 30 moves from the branch pipe 29 side communicating with the lower part of the hot water storage tank 1 to the downstream side of the heating return pipe 27 communicating with the upper part of the hot water storage tank 1. It is a switching control means for switching. Here, the switching control means 46 determines the predetermined switching temperature based on the judgment result of the usage status judging means 45, and if the usage status prioritizes the boiling efficiency, secures high-temperature hot water. The predetermined switching temperature is determined to be lower than that in the priority use situation.

Next, the operation of the heat pump type hot water supply device of the present invention will be described.

<Hot water supply>
When the hot water tap 7 is opened, city water flows into the bottom of the hot water storage tank 1 from the hot water supply pipe 2, hot water comes out from the top of the hot water storage tank 1 through the hot water discharge pipe 3, and the hot water mixing valve 5 is used to bypass the water supply. It is mixed with water from the pipe 4 and passes through the hot water supply pipe 6. When the hot water supply flow rate sensor 8 detects the minimum operating water amount or more, the control means 43 feedback-controls the valve opening degree of the hot water supply mixing valve 5 so that the temperature detected by the hot water supply temperature sensor 9 matches the hot water supply set temperature. , Hot water is supplied at the set temperature. When the hot water supply flow rate sensor 8 detects less than the minimum amount of operating water by closing the hot water supply tap 7 or the like, the control means 43 stops the feedback control of the valve opening degree of the hot water supply mixing valve 5 to stop the hot water supply. There is.

At this time, the hot water amount storage means 44 calculates the hot water amount converted into a predetermined temperature from the hot water supply flow rate detected by the hot water supply flow rate sensor 8, the hot water supply temperature detected by the hot water supply temperature sensor 9, and the water supply temperature detected by the water supply temperature sensor 10. The calculated amount of hot water used is added to the storage area of the day, and the daily use flow rate is stored.

<Automatic bath operation>
Next, the automatic bath operation will be described. When the bath switch 41 of the remote controller 39 is operated, the control means 43 opens the water filling solenoid valve 16 so that the temperature detected by the water filling temperature sensor 15 matches the bath set temperature. Feedback control of the valve opening is performed to start the filling operation at the bath temperature setting.

Then, the control means 43 closes the water filling solenoid valve 16 when the integrated value of the water filling flow rate detected by the water filling flow sensor 14 becomes the bath setting hot water amount or when the water level sensor 24 detects the bath setting water level. Finish the hot water filling operation and keep the bath warm.

In the warming operation of the bath, the control means 43 drives the bath circulation pump 20 at regular intervals while keeping the bath three-way valve 22 on the bath heat exchange bypass pipe 21 side, and confirms the temperature of the bath water with the bath temperature sensor 23. Then, when it is detected that the temperature is lower than the bath set temperature, the bath three-way valve 22 is switched to the bath heat exchanger 18 side to continue circulation, and the bath water is heated by the bath heat exchanger 18. When the bath temperature sensor 23 confirms that the bath water temperature has risen above the bath set temperature, the control means 43 stops driving the bath circulation pump 20 and sets the bath three-way valve 22 to the bath heat exchange bypass pipe 21 side. Switch to.

Further, the control means 43 stores the water level in the bathtub 13 when the filling is stopped based on the detection value of the water level sensor 24, and when the water level in the bathtub 13 drops from the stored water level, the hot water is kept until the original water level. Perform a replenishing operation of the bath.

Then, when the preset bath automatic warming time elapses from the start of the filling of water, the control unit 43 also stops the bath warming operation and the bath refilling operation, and stops the bath automatic operation.

<Boiling operation>
Next, the boiling operation will be described. At the start time of a predetermined time zone (midnight time zone) where the unit price of electric power is inexpensive, the control means 43 starts boiling the amount of hot water commensurate with the hot water supply load amount until then. The compressor 33, the expansion valve 35, the blower 37, and the heating circulation pump 28 are started to drive, and the hot and cold water taken out from the lower portion of the hot water storage tank 1 is heated by the water/refrigerant heat exchanger 34 to the boiling target temperature that matches the hot water supply load amount. When returning to the upper part of the hot water storage tank 1, hot water having a set temperature is boiled up from the upper part of the hot water storage tank 1 and boiled to the bottom of the hot water storage tank 1, or when the end time of the predetermined time zone is reached, the compressor 33 and The expansion valve 35, the blower 37, and the heating circulation pump 28 are stopped, and the boiling operation is completed.

The control means 43 also performs the boiling operation even when it is determined that the amount of remaining hot water in the hot water storage tank 1 has decreased based on the temperature detected by the hot water storage temperature sensor 17, and in this case, in advance, When the temperature detected by the hot water storage temperature sensor 17 at the determined position reaches a predetermined temperature, the boiling operation is ended.

The operation of the boiling operation will be described in detail based on the flowchart shown in FIG.

When the boiling start condition is satisfied (Yes in step S1), the control means 43 switches the switching means 30 to the lower side of the hot water storage tank 1 communicating with the branch pipe 29 (step S2), and the heat pump type heating means 25 raises the water. The boiling operation is started so that the hot water returns to the lower portion of the hot water storage tank 1 (step S3).

Then, the usage status judging means 45 calculates a standard deviation as a value of the variation degree from the information on the daily hot water quantity stored in the hot water quantity storage means 44 (step S4), and the standard deviation value is calculated in advance. Compared with the predetermined value that has been determined (step S5), if the predetermined value or more, the daily amount of hot water used fluctuates greatly, and it is better to give priority to not running out of hot water rather than performing hot water supply in consideration of energy saving. Since it can be considered, it is determined that the usage condition is to give priority to securing high-temperature hot water, and the predetermined switching temperature is set to the first switching temperature (here, 60° C.) (step S6). On the other hand, if the value of standard deviation is less than the predetermined value, it is considered that there is little fluctuation in the amount of hot water used daily and that hot water is being supplied with an awareness of energy saving. The predetermined switching temperature is determined to be the second switching temperature (here, 50° C.) lower than the first switching temperature (step S7).

With the lapse of time from the start of the boiling operation, the temperature of the hot water boiled by the heat pump heating means 25 gradually rises until it reaches the predetermined switching temperature determined in step S6 or step S7. The boiled hot water is returned to the lower part of the hot water storage tank 1 through the branch pipe 29 and does not lower the temperature of the hot water stored in the upper part of the hot water storage tank 1.

When the time further elapses and the temperature of the hot water boiled by the heat pump heating means 25 reaches the predetermined switching temperature determined in step S6 or step S7 (Yes in step S8), the switching means 30 is heated to return to the return pipe 27. Switching to the upper side of the hot water storage tank 1 that communicates with the downstream (step S9), the boiling water is boiled by the heat pump heating means 25 to return to the upper part of the hot water storage tank 1, and the boiling operation is continued.

At this time, when the usage condition is to prioritize securing high-temperature hot water, the temperature of the hot water returning to the upper part of the hot water storage tank 1 is relatively high, so that the hot water stored in the upper part of the hot water storage tank 1 is In the case of a usage situation in which the decrease in temperature can be suppressed and the boiling efficiency is prioritized, the switching means 30 is switched to the tank upper side while the temperature of the hot water returning to the lower portion of the hot water storage tank 1 is relatively low. It is possible to suppress an increase in the temperature of the water stored in the lower portion of the hot water storage tank 1 and suppress a decrease in the heating efficiency of the heat pump heating means 25.

Then, when the boiling operation progresses and the boiling ending condition is satisfied (Yes in step S10), the boiling operation is stopped (step S11).

In this way, the predetermined switching temperature according to the usage status is determined according to the usage status determination result based on the amount of hot water used, so the predetermined switching temperature is set in the usage status where it is not desired to lower the temperature of the upper part of the hot water storage tank. To suppress the temperature drop in the upper part of the hot water storage tank or to raise the temperature in the lower part of the hot water storage tank, lower the predetermined switching temperature to suppress the temperature rise in the lower part of the hot water storage tank to suppress the heat pump heating means. It is possible to suppress a decrease in heating efficiency, and it is possible to perform efficient operation according to the usage situation.

Next, another embodiment of the present invention will be described with reference to the drawings. The same components as those in the previous embodiment are designated by the same reference numerals and the description thereof will be omitted.

FIG. 4 is a control block diagram of another embodiment.
Reference numeral 47 denotes a heat exchange usage record storing means, which stores a usage record indicating how much of the hot water stored in the hot water storage tank 1 has been used for heating an external load such as reheating of a bathtub for each of a plurality of days in the past. Here, here, the time when the bath three-way valve 22 is on the bath heat exchanger 18 side and the bath circulation pump 20 is operating is accumulated and stored as the heat exchange use actual time every day.

Numeral 48 gives priority to boiling efficiency based on the daily hot water usage amount information stored in the hot water usage storage means 44 and the daily heat exchange usage performance information stored in the heat exchange usage performance storage means 47. It is a usage status judging means for judging whether the usage status is to be used or the usage status is to prioritize securing hot water. Here, when the value of the degree of variation in the amount of hot water used is less than a predetermined value and the maximum value of the heat exchange usage actual time is less than the predetermined time, it is determined that the usage status prioritizes boiling efficiency, and in other cases. It is decided that the usage is prioritized to secure hot water.

Next, the operation of the boiling operation of this another embodiment will be described based on the flowchart shown in FIG.

When the boiling start condition is satisfied (Yes in step S1), the control means 43 switches the switching means 30 to the lower side of the hot water storage tank 1 communicating with the branch pipe 29 (step S2), and the heat pump type heating means 25 raises the water. The boiling operation is started so that the hot water returns to the lower portion of the hot water storage tank 1 (step S3).

Then, the usage status judging means 48 calculates the standard deviation as the value of the variation degree from the information on the daily hot water amount stored in the hot water amount storing means 44 (step S4), and further the heat exchange usage record storing means. The maximum value of the heat exchange use actual time in the past plural days is calculated from the information of the daily heat exchange use actual time stored in 47 (step S41).

Then, the usage status judging means 48 compares the value of the standard deviation with a predetermined value which is determined in advance (step S5). It is considered that it is better to give priority to not running out of hot water than to do it. Therefore, it is determined that it is the usage condition that gives priority to securing hot water, and the predetermined switching temperature is set to the first switching temperature (here, 60°C). Is determined (step S6).

On the other hand, when the value of the standard deviation is less than the predetermined value (No in step S5), the maximum value of the heat exchange actual use time is compared with a predetermined time (step S51), and the time is equal to or more than the predetermined time. In this case (No in step S51), the load on the user side such as reheating the bath is large, and it is considered that it is better to prioritize securing the heating capacity on the user side rather than hot water supply in consideration of energy saving. It is determined that the usage is prioritized to secure high-temperature hot water, and the predetermined switching temperature is set to the first switching temperature (here, 60° C.) (step S6).

Further, when the value of the standard deviation is less than the predetermined value (No in step S5) and the maximum value of the heat exchange usage actual time is less than the predetermined time (Yes in step S51), there is little fluctuation in daily hot water usage. In addition, since the load on the user side is small and it is considered that hot water is being supplied with energy saving in mind, it is determined that the usage situation prioritizes boiling efficiency, and the predetermined switching temperature is lower than the first switching temperature. Two switching temperatures (here, 50° C.) are determined (step S7).

With the lapse of time from the start of the boiling operation, the temperature of the hot water boiled by the heat pump heating means 25 gradually rises until it reaches the predetermined switching temperature determined in step S6 or step S7. The boiled hot water is returned to the lower part of the hot water storage tank 1 through the branch pipe 29 and does not lower the temperature of the hot water stored in the upper part of the hot water storage tank 1.

When the time further elapses and the temperature of the hot water boiled by the heat pump heating means 25 reaches the predetermined switching temperature determined in step S6 or step S7 (Yes in step S8), the switching means 30 is heated to return to the return pipe 27. Switching to the upper side of the hot water storage tank 1 that communicates with the downstream (step S9), the boiling water is boiled by the heat pump heating means 25 to return to the upper part of the hot water storage tank 1, and the boiling operation is continued.

At this time, when the usage condition is to prioritize securing high-temperature hot water, the temperature of the hot water returning to the upper part of the hot water storage tank 1 is relatively high, so that the hot water stored in the upper part of the hot water storage tank 1 is In the case of a usage situation in which the decrease in temperature can be suppressed and the boiling efficiency is prioritized, the switching means 30 is switched to the tank upper side while the temperature of the hot water returning to the lower portion of the hot water storage tank 1 is relatively low. It is possible to suppress an increase in the temperature of the water stored in the lower portion of the hot water storage tank 1 and suppress a decrease in the heating efficiency of the heat pump heating means 25.

Then, when the boiling operation progresses and the boiling ending condition is satisfied (Yes in step S10), the boiling operation is stopped (step S11).

In this way, the predetermined switching temperature according to the usage status is determined according to the usage status determination result based on the amount of hot water used, so the predetermined switching temperature is set in the usage status where it is not desired to lower the temperature of the upper part of the hot water storage tank. To suppress the temperature drop in the upper part of the hot water storage tank or to raise the temperature in the lower part of the hot water storage tank, lower the predetermined switching temperature to suppress the temperature rise in the lower part of the hot water storage tank to suppress the heat pump heating means. It is possible to suppress a decrease in heating efficiency, and it is possible to perform efficient operation according to the usage situation.

It should be noted that 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 bathtub 13 is connected as a load of the utilization side heat exchanger to heat the bath water. However, it is also possible to connect a hot water heating terminal as a load of the use side heat exchanger and heat the circulating water for heating. Further, although the configuration in which the utilization side heat exchanger is provided inside the hot water storage tank 1 has been described, the utilization side heat exchanger is configured as a plate heat exchanger or the like and provided outside the hot water storage tank 1, and the upper portion of the hot water storage tank 1 is provided. Alternatively, the hot water may be circulated to the primary side of the utilization side heat exchanger.

In addition, a condition that the maximum value of the amount of hot water used does not exceed a predetermined amount is added to the condition that the maximum value of the amount of hot water used is added to the judgment materials of the usage condition judgment means 45 and 48, and the condition of the usage condition that gives priority to boiling efficiency is determined. Then, the accuracy of determining the usage status in which boiling efficiency is prioritized may be increased.

1 Hot water storage tank 18 Bath heat exchanger (use side heat exchanger)
25 heat pump type heating means 26 heating forward pipe 27 heating return pipe 29 branch pipe 30 switching means 32 boiling temperature sensor 44 used hot water amount storage means 45 usage status judgment means 46 switching control means 47 heat exchange usage record storage means 48 usage status judgment means

Claims (4)

A hot water storage tank for storing hot water, a heat pump type heating means for heating hot water in the hot water storage tank, a heating forward pipe connecting the lower part of the hot water storage tank and an inlet side of the heat pump type heating means, and the heat pump type heating means Heating return pipe connecting the outlet side of the hot water storage tank to the upper part of the hot water storage tank, a branch pipe branched from the heating return pipe and connected to the lower part of the hot water storage tank, and hot water from the heat pump heating means to the upper part of the hot water storage tank. Or a boiling temperature sensor for detecting the temperature of hot water heated by the heat pump heating means, and a boiling temperature sensor. When the detected temperature becomes equal to or higher than a predetermined switching temperature, a switching control unit that switches the switching unit from the lower side of the hot water storage tank to the upper side of the hot water storage tank, and a hot water amount storage unit that stores the hot water amount for the past multiple days for each day. And a usage status determining unit that calculates a value of the degree of variation in the usage amount of hot water based on the information stored in the usage amount storage unit, wherein the switching control unit includes the variation calculated by the usage status determining unit. The heat pump type hot water supply device is characterized in that when the degree value is less than a predetermined value, the predetermined switching temperature is determined to be lower than when the variation degree value is a predetermined value or more. The usage status determination means determines whether or not the maximum value of the amount of hot water used exceeds a predetermined amount, and the switching control means has a value of the variation degree less than a predetermined value and the maximum value of the amount of hot water used is a predetermined amount. When not exceeding, the predetermined switching temperature is determined to be lower than when the value of the degree of variation is a predetermined value or more and when the maximum value of the amount of hot water used exceeds a predetermined amount. The heat pump hot water supply apparatus according to claim 1. A heat exchange usage record memory that stores, for each day, a usage-side heat exchanger that heats bath water or heating circulating water using the hot water in the hot water storage tank as a heat source, and a value that represents the usage history of the usage-side heat exchanger for the past multiple days Means, the switching control means, if the value of the variation degree is less than a predetermined value and the value representing the usage record stored in the heat exchange usage record storage means is less than a predetermined value, the variation degree value. Is greater than or equal to a predetermined value and the value representing the usage record stored in the heat exchange usage record storage means is greater than or equal to a predetermined value, the predetermined switching temperature is determined to be a lower temperature. The heat pump water heater according to claim 1. The usage status determination means determines whether or not the maximum value of the amount of hot water used exceeds a predetermined amount, and the switching control means stores the value of the degree of variation less than a predetermined value and the heat exchange usage record storage means. When the value representing the used performance is less than a predetermined value and the maximum value of the amount of hot water used does not exceed the predetermined amount, the value of the degree of variation is a predetermined value or more, and the use stored in the heat exchange use result storing means. 4. The predetermined switching temperature is determined to be lower than when the value representing the actual result is equal to or more than a predetermined value and when the maximum value of the amount of hot water used exceeds the predetermined amount. Heat pump water heater.

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