JP7342643B2 - Hot water storage type water heater - Google Patents

Description

The present invention relates to a hot water storage type water heater.

In the control described in Patent Document 1 to prevent piping from freezing in a hot water storage type water heater, when the water supply temperature reaches a predetermined temperature at which there is a possibility of freezing, the circulation pump is operated and the water is pumped to the bottom or top of the hot water storage tank. The hot water taken out from the hot water storage tank is returned to the hot water storage tank via piping that connects the hot water storage tank and the heat pump unit.

Japanese Patent Application Publication No. 2003-314897

The speed at which the temperature inside the water heater decreases varies depending on the outside temperature and its fluctuations. Therefore, if the timing for starting freeze prevention control is set uniformly when the supply water temperature reaches a predetermined temperature, there is a possibility that the freeze prevention will not be done in time and the pipes will freeze, and the outside temperature will rise. There is a possibility that freeze prevention control will be executed even though freeze prevention is no longer necessary due to such reasons. In this respect, there is room for improvement in the control disclosed in Patent Document 1, and it is desired to develop a freeze prevention control that can be executed at an appropriate timing based on actual temperature changes in the water heater.

In addition, instead of using freeze prevention control, a method can also be considered in which a heater is installed in the piping to prevent freezing and the inside of the water heater is heated as necessary. However, from the viewpoint of reducing costs and suppressing electrical leakage, etc., it is not preferable to prevent freezing by installing a heater.

The present invention has been made in order to solve the above-mentioned problems, and has been improved so that freeze prevention can be controlled more efficiently and at a more appropriate timing without the need to separately install a heater or the like for freezing prevention. The present invention provides a hot water storage type hot water supply device.

The hot water storage type hot water supply device of the present invention includes a hot water storage tank, a heat pump unit that performs a boiling operation to heat hot water in the hot water storage tank, a water supply unit connected to the lower part of the hot water storage tank for supplying water to the hot water storage tank, and a water supply unit. The system includes a temperature detecting means for detecting the supply water temperature, which is the water temperature of the hot water tank, a remaining hot water amount detecting means for detecting the amount of remaining hot water in the hot water storage tank, and a control device for controlling the operation of the boiling operation. The control device includes a freeze prevention control execution unit that performs freeze prevention control to prevent freezing when the water supply temperature becomes equal to or lower than the first determination temperature. When executing freeze prevention control, the freeze prevention control execution means operates in a first mode in which the entire amount of hot water in the hot water storage tank is boiled, and in a second mode in which a part of the hot water on the lower side of the hot water storage tank is boiled. If the remaining hot water amount is less than the standard amount, select the first mode as the selection mode, and if the remaining hot water amount is more than the standard amount, select the second mode as the selection mode. Boiling is started in the selection mode so that the boiling is completed at the timing when the water supply temperature reaches the second determination temperature that is lower than the first determination temperature.

According to the hot water storage type water heater according to the present invention, efficient freezing prevention control is performed according to the amount of hot water remaining in the hot water storage tank at an appropriate timing according to temperature changes, without separately installing a heater for freezing prevention. can be executed.

1 is a configuration diagram of a hot water storage type hot water supply device according to Embodiment 1 of the present invention. FIG. 3 is a diagram showing a boiling circuit in a first mode according to Embodiment 1 of the present invention. FIG. 3 is a diagram showing a boiling circuit in a second mode according to the first embodiment of the present invention. It is a flowchart which shows the control operation of the freeze prevention driving|operation of Embodiment 1 of this invention. 3 is a timing chart of freeze prevention operation according to Embodiment 1 of the present invention.

Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. Common elements in each figure are given the same reference numerals and redundant explanations will be omitted. Note that in the present disclosure, the amount of heat that hot water has may be treated as the amount of hot water converted to hot water at a predetermined temperature. That is, in the present disclosure, the description "amount of hot water" may substantially mean the amount of heat.

Embodiment 1.
FIG. 1 is a configuration diagram of a hot water storage type water heater according to Embodiment 1 of the present invention. The hot water storage type hot water supply device 35 includes a tank unit 33, a heat pump unit (hereinafter referred to as "HP unit") 7 that uses a heat pump cycle, and a remote control device 44.

The HP unit 7 and the tank unit 33 are connected via an HP forwarding pipe 14, an HP return pipe 15, and electrical wiring (not shown). The HP unit 7 functions as a heating means for heating low temperature water etc. led from the hot water storage tank 8 included in the tank unit 33. The HP unit 7 includes a compressor 1, a water-refrigerant heat exchanger 3, an expansion valve 4, and an air heat exchanger 6 connected in a ring shape through a refrigerant circulation pipe 5 to form a heat pump cycle. The water-refrigerant heat exchanger 3 is for exchanging heat between the refrigerant flowing through the refrigerant circulation pipe 5 and the low-temperature water led from the tank unit 33. Further, the water-refrigerant heat exchanger 3 may be configured to exchange heat between the refrigerant flowing through the refrigerant circulation pipe 5 and low-temperature water directly supplied from a water source such as tap water. An outside air temperature sensor 39 is installed in the HP unit 7 to detect outside air temperature.

The tank unit 33 includes the following various parts and piping. The hot water storage tank 8 is for storing hot water. Temperature stratification is formed in the hot water storage tank 8, with the upper side having a higher temperature and the lower side having a lower temperature, and hot water is stored therein. A plurality of hot water temperature sensors 41, 42, and 43 are attached to the surface of the hot water storage tank 8 at different heights.

The tank unit 33 includes a heat source pump 12 and a bath heat exchanger 20 built therein. The heat source pump 12 is a pump for circulating hot water through various pipes described later in the tank unit 33, and is provided on the first water pipe 13a.

The three-way valve 11 is a flow path switching means having ports a and b which are inlets and a port c which is an outlet. The first water supply pipe 13a connects the c port of the three-way valve 11 and the HP going pipe 14. The three-way valve 11 has a form in which the water outlet pipe 10 connected to the water outlet 8b at the lower part of the hot water storage tank 8 communicates with the HP outgoing pipe 14 (a-c route), and one of the bath heat exchangers 20. The hot water flow path in the tank unit 33 is connected to one of two flow path configurations: a configuration in which the third tank circulation piping 20c connected to the next side outlet communicates with the HP outbound piping 14 (b-c path); Switch.

The first four-way valve 16 is a flow path switching means having a port and b port which are inflow ports, and a c port and d port which are outflow ports. The first four-way valve 16 switches the flow path configuration to any one of four routes: an ac route, an ad route, a bc route, and a bd route. The second four-way valve 18 is a flow path switching means having an a port which is an inflow port, and b ports, c port, and d port which are outflow ports. The second four-way valve 18 switches the flow path between three paths: a-b path, a-c path, and ad path.

The tank unit 33 includes a medium temperature pipe 79, a first water supply pipe 9a, a second water supply pipe 9b, a third water supply pipe 9c, a fourth water supply pipe 9d, a hot water supply mixing valve 22, a bath mixing valve 23, and a medium temperature water switching valve 78. , a hot water supply pipe 24, and a bath pipe 25. One end of the first water supply pipe 9a is connected to a water source such as a tap water supply, and the other end of the first water supply pipe 9a is connected to a second water supply pipe 9b and a third water supply pipe 9c via a pressure reducing valve 31. A conduit 9 is configured. Further, the first water supply pipe 9a is provided with a water supply temperature sensor 60 that detects the temperature of the water supply section. The second water supply pipe 9b branches from the middle and is connected to the a port of the medium temperature water switching valve 78. The medium temperature pipe 79 connects the medium temperature water outlet 8f provided in the middle of the hot water storage tank 8 to the b port of the medium temperature water switching valve 78.

One end of the fourth water supply pipe 9d is connected to the c port of the medium temperature water switching valve 78, and the other end is branched from the middle and connected to the water side inlets of the hot water supply mixing valve 22 and the bath mixing valve 23, respectively. . One end of the hot water outlet pipe 21 is connected to the hot water introduction outlet 8d at the top of the hot water storage tank 8, and the other end is branched from the middle and connected to the hot water side inlets of the hot water supply mixing valve 22 and bath mixing valve 23, respectively. ing.

The hot water supply mixing valve 22 adjusts the hot water temperature by varying the flow rate ratio between the hot water supplied by the hot water outlet pipe 21 and the low temperature water or medium temperature water supplied from the fourth water supply pipe 9d. An outlet of the hot water supply mixing valve 22 is connected to one end of a hot water supply pipe 24 . The other end of the hot water supply pipe 24 is connected to a hot water tap 34. The hot water whose temperature has been adjusted by the hot water supply mixing valve 22 passes through the hot water supply piping 24, the hot water tap 34, and an external piping (not shown) connected to the hot water tap 34 to a shower, a sink, a sink (not shown), and a hot water tap 34. Sent to washbasin faucets, etc.

The bath mixing valve 23 adjusts the hot water temperature by varying the flow rate ratio between the high temperature hot water supplied by the hot water outlet pipe 21 and the low temperature water or medium hot water supplied from the fourth water supply pipe 9d. The outlet of the bath mixing valve 23 is connected to one end of the bath pipe 25. The other end of the bath pipe 25 is connected to a position of the bath pipe 27 between the bath heat exchanger 20 and the bath temperature sensor 37. A bath electromagnetic valve 26 for opening and closing the bath piping 25 is provided in the middle of the bath piping 25. The hot water whose temperature has been adjusted by the bath mixing valve 23 flows into the bathtub 30 via the bath pipe 25 and the bath pipe 27.

The suction port and the discharge port provided in the bathtub 30 are connected by a flow pipe 27 and a flow return pipe 28, respectively, so that the bath water in the bathtub 30 is drawn out and circulated. The bath heat exchanger 20 is installed in the middle of the bath return pipe 28. A first tank circulation pipe 20a is connected to the primary side inlet of the bath heat exchanger 20. The bath heat exchanger heats target water on the secondary side using high temperature hot water supplied from the hot water storage tank 8 or HP unit 7, or uses low temperature water supplied from the lower part of the hot water storage tank 8. Heat is recovered from the target water on the secondary side for cooling. A third tank circulation pipe 20c is connected to the outlet of the bath heat exchanger 20. The second tank circulation pipe 20b branches from the middle of the third tank circulation pipe 20c and is connected to the middle of the medium temperature pipe 79. A check valve 50 is installed in the second tank circulation pipe 20b. A bath circulation pump 29 for circulating bath water is installed in the middle of the bath return piping 27 and the bath return piping 28.

A control device 36 is built into the tank unit 33. Control device 36 includes at least one processor and at least one memory. The operations of various valves, pumps, etc. provided in the tank unit 33 and the HP unit 7 are controlled by a control device 36 electrically connected thereto.

The control device 36 and the remote control device 44 are connected to be able to communicate with each other. The remote control device 44 is a user interface device that commands the operation of the hot water storage type water heater 35 and changes the set values. There is no limitation on the installation location of the remote control device 44. Examples of locations where the remote control device 44 is installed include a bathroom, a kitchen, and the like. Further, the number of remote control devices 44 may be one, or a plurality of remote control devices may be installed at different locations. In addition to the remote control device 44, a mobile terminal such as a smartphone may be usable as a user interface of the hot water storage type water heater 35, for example.

The remote control device 44 includes a display section 44a that functions as a notification means and an operation section (not shown) that functions as a setting means. The display section 44a may be, for example, a liquid crystal display or an organic EL display. The display unit 44a can display, for example, information regarding the status of the hot water storage type hot water supply device 35, information regarding the settings of the hot water storage type hot water supply device 35, and the like. The operation unit may include buttons, dials, keys, etc. for user operation. The display section 44a may be a touch screen that also functions as an operation section. The remote control device 44 may further include a speaker, a microphone, and the like.

The user can operate the remote control device 44 to set, for example, the temperature of the bath and the amount of hot water in the bath. Further, the user can operate the remote control device 44 to set automatic bath operation. When automatic bath operation is set, the temperature of the bath water and the amount of hot water in the bathtub 30 are maintained at the temperature and amount of water set by the remote control device 44, as necessary. A bath is held.

The control device 36 detects the amount of remaining hot water and the amount of heat storage in the hot water storage tank 8 by detecting the temperature distribution of hot water in the hot water storage tank 8 using hot water storage temperature sensors 41 , 42 , and 43 . The control device 36 controls the start and stop of the boiling operation of the hot water in the hot water storage tank 8 by the HP unit 7 based on the detected amount of remaining hot water, amount of heat storage, and the like.

The control device 36 performs boiling operation by operating the HP unit 7 and the heat source pump 12. In the boiling operation, by switching the three-way valve 11, the first four-way valve 16, and the second four-way valve 18, the water in the lower part of the hot water storage tank 8 is led out from the water outlet 8b, and is transferred to the HP going pipe 14. etc., and is sent to the HP unit 7. The hot water, which is heated to a high temperature while passing through the water-refrigerant heat exchanger 3, flows into the hot water storage tank 8 via the HP return pipe 15 and the like. Through such boiling operation, hot water is stored in the hot water storage tank 8 from top to bottom, and heat is stored. When the amount of hot water remaining in the hot water storage tank 8 as determined by the hot water storage temperature sensor 41, 42, or 43 exceeds a predetermined amount, it is stopped.

The control device 36 of the present embodiment further functions as a freeze prevention control execution unit that executes freeze prevention control to prevent piping of the hot water storage type water heater from freezing. In the freeze prevention control, boiling is performed in either the first mode or the second mode below. Figures 2 and 3 are boiling circuit diagrams in which the flow path of hot water during boiling is added with bold lines to the configuration diagram in Figure 1, and Figure 2 is for the first mode, and Figure 3 is for the second mode. shows.

In the first mode, the entire amount of hot water in the hot water storage tank 8 is heated up. In the first mode, as shown in FIG. , the first water supply pipe 13a, the HP outgoing pipe 14, the HP unit 7, the HP return pipe 15, the first hot water pipe 17a, the fourth hot water pipe 19b, and the hot water introduction outlet 8d at the top of the hot water storage tank 8 are in communication with each other. The flow path is switched to In the first mode, the hot water in the hot water storage tank 8 is led out from the lower part of the hot water storage tank 8, and the hot water is returned to the upper part of the hot water storage tank 8. Boiling in the first mode is completed when the entire amount of hot water in the hot water storage tank 8 reaches the temperature set in the control device 36 at the time of full amount boiling.

In the second mode, a boiling operation is performed in which a portion of the hot water in the lower part of the hot water storage tank 8 is boiled. In the second mode, the three-way valve 11 and the first four-way valve 16 operate the water outlet 8b at the lower part of the hot water storage tank 8, the water outlet pipe 10, the first water supply pipe 13a, The flow path is switched to a configuration in which the HP outgoing pipe 14, the HP unit 7, the HP return pipe 15, the second hot water pipe 17b, and the water inlet 8c at the lower part of the hot water storage tank 8 are communicated with each other. In the second mode, the hot water stored below the hot water storage tank 8 is led out from the lower part of the hot water storage tank 8, and the high temperature hot water is returned to the lower part of the hot water storage tank 8. Boiling in the second mode is completed when the lower part of the hot water storage tank 8 reaches the temperature set in the control device 36 for lower part boiling (for example, lower minimum temperature of 40° C.).

When performing freeze prevention control, the control device 36 determines whether to perform boiling in the first mode or in the second mode, depending on the amount of hot water remaining in the hot water storage tank 8. A reference amount is set in advance as a comparison value for the amount of remaining hot water and is stored in the control device 36. If the remaining amount of hot water is less than the standard amount, the first mode is selected in which the entire amount of hot water in the hot water storage tank 8 is boiled, and if the remaining amount is more than the standard amount, a part of the hot water in the lower part of the hot water storage tank 8 is boiled. A second mode is selected. The reference amount can be determined to be an optimal value for each hot water storage type hot water supply device 35 through simulation or the like. As a specific reference amount, for example, a value of the remaining amount of hot water, which is about half of the total amount in the hot water storage tank 8, is used.

A first judgment temperature and a second judgment temperature are recorded in advance in the control device 36 as comparison values for the water temperature measured by the feed water temperature sensor 60 (hereinafter also referred to as "feed water temperature"). The first determination temperature is a temperature for determining the possibility of freezing, and the second determination temperature is a temperature for determining the possibility that pipe freezing will actually occur. The second judgment value is lower than the first judgment temperature.

The control device 36 calculates the timing of starting the boiling operation in the first mode or the second mode when the water supply temperature falls below the first determination temperature. The start timing of the boiling operation is set so that the boiling in the selected mode is completed when the water temperature reaches the second determination temperature.

Specifically, when calculating the boiling start timing, the control device 36 first calculates the amount of temperature change ΔTw in the water supply temperature per unit time based on the data on the water supply temperature. Note that in this embodiment, the unit time will be described as one hour. Then, using the calculated temperature change amount ΔTw, the arrival time T1, which is an estimated value of the time required for the water temperature to drop to the second determination temperature from the time when it becomes below the first determination temperature, is calculated by the following formula.

Next, a boiling time T2, which is an estimated value of the boiling time required from the start to the completion of boiling in the selected mode, is calculated. That is, when the first mode is selected, the time required to boil the entire amount of hot water storage tank 8 is calculated, and when the second mode is selected, the lower part of hot water storage tank 8 is calculated. The time required to reach the temperature is calculated.

Specifically, the boiling time T2 is calculated by the following formula.

In the above equation, the target boiling temperature is calculated by the control device 36 from the outside temperature, the amount of hot water used, and the like. The amount of remaining hot water is calculated based on the outputs of the hot water storage temperature sensors 41 to 43. The capacity of the hot water storage tank 8 is stored in the control device 36. Further, the currently set heating capacity of the HP unit 7 is acquired by the control device 36.

The waiting time, which is the time from when the first determination temperature is reached until the start of boiling, is calculated as the value (T1-T2) obtained by subtracting the boiling time T2 from the arrival time T1. The control device 36 sets the timing at which the waiting time has elapsed after reaching the first determination temperature as the timing to start boiling in the selected mode.

Next, a more specific control operation of freeze prevention control executed by the control device 36 will be described. FIG. 4 is a flowchart showing the control operation of freeze prevention control by the control device 36. The control shown in FIG. 4 is repeatedly executed at regular intervals. In step S1 of FIG. 4, it is determined whether the water temperature of the water supply section is lower than or equal to the first determination temperature. In step S1, if it is determined that the water temperature in the water supply section is higher than the first determination temperature, the current process ends as is.

On the other hand, if it is determined that the water temperature in the water supply section is below the first determination temperature, then the process proceeds to step S2, where it is determined whether the amount of hot water remaining in the hot water storage tank 8 is less than the reference amount. In step S2, if it is determined that the amount of remaining hot water is less than the reference amount, the process proceeds to step S3, and the first mode is selected, and if it is determined that the amount of remaining hot water is greater than or equal to the reference amount, the process proceeds to step S4. , the second mode is selected.

After step S3 or step S4, the process proceeds to step S5, where the standby time in the selected mode is calculated. The waiting time is calculated as described above. Next, the process proceeds to step S6, where it is determined whether the elapsed time after reaching the first determination temperature is equal to or longer than the standby time. If the elapsed time is not equal to or longer than the waiting time, the process returns to step S6, and the determination process of step S6 is repeated at regular intervals.

On the other hand, if it is determined in step S6 that the elapsed time is equal to or longer than the standby time, the process then proceeds to step S7, where boiling to prevent freezing is started. After that, the current process ends.

FIG. 5 is a timing chart of freeze prevention operation in the first mode of this embodiment. In FIG. 5, the horizontal axis represents time, the left side of the vertical axis represents temperature, and the right side represents the amount of remaining hot water. Moreover, in FIG. 5, a solid line a shows the temperature change of the water supply part, and a solid line b shows the amount of remaining hot water. In the example of FIG. 5, the first judgment temperature is set to 4.0 [°C], and the second judgment temperature is set to -3.0 [°C]. Further, the temperature change amount ΔTw is −1 [° C.].

In the example shown in FIG. 5, at time t1 when the water supply temperature becomes equal to or lower than the first determination temperature 4.0 [° C.], the amount of remaining hot water is acquired, the first mode is selected, and the standby time is calculated. In this example, the boiling time in the first mode is 1.5 hours and the standby time is 5.5 hours. Boiling starts at time t2 when the elapsed time from time t1 reaches the waiting time. Since the first mode is a full boiling operation, the remaining amount of hot water increases, and at time t3, 1.5 hours after the boiling time has elapsed, the tank reaches a full state, and the boiling to prevent freezing is also possible. Complete.

In addition, if the first judgment temperature, second judgment temperature, and temperature change amount ΔTw are the same as in this example, and the boiling time in the second mode is 0.5 [h], the standby time in the second mode is , 6.5 hours later.

As explained above, according to the control of this embodiment, the amount of hot water remaining in the hot water storage tank 8 is taken into consideration, an appropriate boiling operation mode is selected, and the temperature at which freezing is expected to start is reached. Boiling is started at the optimal timing when boiling is completed. Therefore, freeze prevention control can be executed at a more appropriate timing, and while freezing can be more reliably prevented, wasteful boiling operation for freezing prevention can be avoided.

In addition, the control device 36 controls the supply water temperature to make a second determination during the standby time after the supply water temperature becomes equal to or lower than the first determination temperature, that is, before starting boiling for freezing prevention according to the selected mode. The configuration may be such that when the temperature drops below the temperature, the boiling operation is immediately performed. The boiling operation in this case may be configured to be boiling operation in the selected mode, or may be boiling in the first mode or boiling in the second mode regardless of the selected mode. It is also possible to adopt a configuration in which the height is increased.

Further, although the first determination temperature and the second determination temperature are values stored in advance in the control device 36, a configuration may be adopted in which the user can change these determination temperatures using the remote control device 44 or the like.

Moreover, the control device 36 may be configured to not perform the boiling operation when it detects that a failure occurs in the HP unit 7 that does not allow the boiling operation. In this case, when the first mode is selected, the hot water in the lower part of the hot water storage tank 8 is circulated to the upper part of the hot water storage tank 8 via the HP unit 7, and when the second mode is selected, , the hot water in the lower part of the hot water storage tank 8 may be configured to be operated to circulate through the HP unit 7 to the lower part of the hot water storage tank 8. This makes it possible to prevent freezing even when the HP unit 7 breaks down.

Further, even if the user sets the boiling prohibition mode that prohibits boiling operation in the HP unit 7 by operating the remote control device 44 or the like, the control device 36 controls the above-mentioned freezing prevention boiling operation. It is also possible to have a configuration that can execute. This makes it possible to more reliably prevent freezing.

The control device 36 may be configured to provide notification by displaying guidance to the effect that the freezing prevention boiling operation is in progress on the display unit 44a of the remote control device 44 while the freezing prevention boiling operation is being carried out. This allows the user to confirm that the device is not malfunctioning.

When the heating capacity of the heat pump unit 7 is configured to be switchable, the control device 36 makes the heating capacity of the HP unit 7 during boiling in the first mode larger than the heating capacity during boiling in the second mode. It may also be a configuration. In the second mode, since the amount of hot water remaining in the hot water storage tank 8 is large, the atmospheric temperature in the hot water storage tank 8 is high, and the amount of boiling water is smaller than in the first mode. Therefore, it is considered that the urgency of freezing prevention under the circumstances where the second mode is selected is low. Therefore, in the second mode, the heating capacity of the HP unit 7 is adjusted to be low to reduce energy consumption. Specifically, for example, when the heating capacity of the HP unit 7 in the first mode is 2.0 L/min, the heating capacity of the HP unit 7 in the second mode is set to 1.5 L/min, etc. The heating capacity is suppressed to about 75% of the heating capacity in the first mode.

During the standby time before the start of the boiling operation in the first mode, the control device 36 takes out hot water from the circulation flow path in the second mode (i.e., from the lower part of the hot water storage tank 8 and stores the hot water via the HP unit 7). The hot water in the lower part of the hot water storage tank 8 may be circulated for a predetermined period of time through a path for flowing into the lower part of the tank 8. When the first mode is selected, it can be determined that freezing prevention is more urgent than when the second mode is selected. Therefore, by circulating hot water through the HP unit 7 before the boiling operation starts, the flow path in the lower part of the hot water storage tank 8, which is particularly likely to freeze, is By circulating the fluid, it is possible to ensure the reliability of freezing prevention.

Even if any component built into the hot water storage type water heater is in a failure state, the control device 36 controls whether the component is a component that is not related to the execution of the boiling operation to prevent freezing, that is, If the component is not placed on the boiling circuit in each mode of FIGS. 2 and 3, it may be configured to execute boiling operation for freezing prevention in the first mode or the second mode. . Thereby, freezing damage to the boiling circuit can be prevented.

When the hot water storage tank 8 is in a full state where the hot water boiling operation cannot be performed, the control device 36 does not perform the boiling operation using the HP unit 7 and controls the hot water storage tank 8 in the flow path of the second mode. It may be configured to only circulate hot water. Thereby, freezing of the lower part of the hot water storage tank 8 can be prevented.

The hot water storage type water heater may be configured to further include a freeze prevention prohibition means for prohibiting the execution of boiling to prevent freezing by the user operating the remote control device 44 or the like. In this case, the control device 36 is configured not to perform freeze prevention control even if the freeze prevention operating conditions are met when prohibition of the boiling operation for freeze prevention is set. This makes it possible to reliably stop the freeze prevention operation when checking for a malfunctioning part of the water heater.

1 Compressor, 3 Water refrigerant heat exchanger, 4 Expansion valve, 5 Refrigerant circulation piping, 6 Air heat exchanger, 7 HP unit, 8 Hot water storage tank, 8a Water inlet, 8b Water outlet, 8c Water inlet, 8d Hot water introduction outlet, 8e Hot water introduction outlet, 8f Medium temperature water outlet, 8g Medium temperature water inlet, 9 Water supply pipe, 9a First water supply pipe, 9b Second water supply pipe, 9c Third water supply pipe, 9d Fourth water supply pipe, 10 water outlet piping, 11 three-way valve, 12 heat source pump, 13a first water supply piping, 13b second water supply piping, 14 HP forward piping, 15 HP return piping, 16 first four-way valve, 17a first hot water piping, 17b 2nd hot water piping, 18 2nd four-way valve, 19a 3rd hot water piping, 19b 4th hot water piping, 19c 5th hot water piping, 20 Bath heat exchanger, 20a 1st tank circulation piping, 20b 2nd tank circulation piping , 20c Third tank circulation piping, 21 Hot water outlet piping, 22 Hot water supply mixing valve, 23 Bath mixing valve, 24 Hot water supply piping, 25 Bath piping, 26 Solenoid valve for bath, 27 Bath return piping, 28 Bath return piping, 29 bath circulation pump, 30 bathtub, 31 pressure reducing valve, 33 tank unit, 34 hot water tap, 35 hot water storage type hot water supply device, 36 control device, 37 bath temperature sensor, 39 outside air temperature sensor, 41 hot water storage temperature sensor, 42 storage hot water temperature, 43 hot water storage temperature sensor, 44 remote control device, 50 check valve, 60 water supply temperature sensor, 78 medium temperature water switching valve, 79 medium temperature piping

Claims (11)

hot water storage tank,
a heat pump unit that performs a boiling operation to heat hot water in the hot water storage tank;
a water supply unit connected to a lower part of the hot water storage tank for supplying water to the hot water storage tank;
temperature detection means for detecting a water supply temperature that is the water temperature of the water supply section;
Remaining hot water amount detection means for detecting the amount of hot water remaining in the hot water storage tank;
a control device that controls the operation of the boiling operation;
Equipped with
The control device includes a freeze prevention control execution unit that performs freeze prevention control to prevent freezing when the water supply temperature becomes equal to or lower than a first determination temperature,
When the freeze prevention control execution means executes the freeze prevention control,
The amount of remaining hot water is the standard from either a first mode in which the entire amount of hot water in the hot water storage tank is boiled, or a second mode in which a part of the hot water on the lower side of the hot water storage tank is boiled. If the amount of remaining hot water is less than the reference amount, the first mode is selected as the selection mode, and if the amount of remaining hot water is greater than or equal to the reference amount, the second mode is selected as the selection mode,
Starting boiling in the selection mode so that the boiling in the selection mode is completed at the timing when the feed water temperature reaches a second judgment temperature lower than the first judgment temperature,
A hot water storage type water heater configured as follows. The freezing prevention control execution means includes:
Calculating an estimated value of the time required from the start to completion of boiling in the selected mode as boiling time,
Based on the amount of temperature change per unit time in the supply water temperature, the time required for the supply water temperature to reach a second determination temperature lower than the first determination temperature from the time when the supply water temperature becomes equal to or lower than the first determination temperature. Calculate the estimated value as the arrival time,
Starting the boiling operation in the selection mode when the time elapsed from the time when the feed water temperature became equal to or less than the first determination temperature becomes a time obtained by subtracting the boiling time from the arrival time.
The hot water storage type hot water supply device according to claim 1, configured as follows. The freeze prevention control execution means may cause the temperature of the water supply section to become below the second judgment temperature after the temperature of the water supply section becomes below the first judgment temperature and before the start of boiling in the selection mode. 3. The hot water storage type water heater according to claim 1, wherein the hot water storage type water heater immediately starts the boiling operation when the hot water is heated. The freezing prevention control execution means includes:
If a failure occurs in the heat pump unit that prevents the boiling operation,
When the selection mode is the first mode, circulating hot water in the lower part of the hot water storage tank to the upper part of the hot water storage tank via the heat pump unit,
When the selection mode is the second mode, circulating the hot water in the lower part of the hot water storage tank to the lower part of the hot water storage tank via the heat pump unit;
The hot water storage type hot water supply device according to any one of claims 1 to 3, configured as follows. Further comprising a setting means for setting a boiling prohibition mode that prohibits the boiling operation,
5. The freezing prevention control execution means is configured to be able to execute boiling in the first mode or the second mode even when the boiling prohibition mode is set. The hot water storage type hot water supply device according to any one of Item 1. Further comprising a notification means capable of notifying a user of the operating state of the hot water storage type water heater,
The freezing prevention control execution means is configured to notify a user, by means of the notification means, that a boiling operation for freezing prevention is being carried out during the execution of boiling in the first mode or the second mode. The hot water storage type hot water supply device according to any one of claims 1 to 5, configured to:. The heating capacity of the heat pump unit is switchable between a plurality of heating capacities,
The freezing prevention control execution means is configured to set the heating capacity of the heat pump unit when performing boiling in the first mode to be larger than the heating capacity of the heat pump when performing boiling in the second mode. The hot water storage type hot water supply device according to any one of claims 1 to 6. The freezing prevention control execution means is characterized in that, before starting the boiling operation in the first mode, hot water is circulated from the lower part of the hot water storage tank to the lower part of the hot water storage tank via the heat pump unit. The hot water storage type hot water supply device according to any one of claims 1 to 7. The freezing preventive control execution means may be configured to perform the freezing prevention control execution means, even if the unit is in a failure determination state in which a failure has been determined in any component constituting the hot water storage type hot water supply device.
9. According to any one of claims 1 to 8, the boiling method is configured such that when boiling in the first mode or the second mode is possible, boiling in the first mode or the second mode can be performed. The hot water storage type water heater described. When the hot water storage tank is full and the boiling operation cannot be executed, the freeze prevention control execution means:
10. The heat pump unit according to claim 1, wherein the heat pump unit is not operated and hot water is circulated from the lower part of the hot water storage tank to the lower part of the hot water storage tank via the heat pump unit. Hot water storage type water heater. further comprising a setting means for setting prohibition of execution of boiling of the freeze prevention control,
Any one of claims 1 to 10, wherein the freezing prevention control execution means is configured not to execute the freezing prevention control when prohibition of execution of the boiling operation of the freezing prevention control is set. The hot water storage type water heater described in .

Images