JP6967739B2 - Water heater - Google Patents

Description

The present invention relates to a water heater having a reheating function for heating bathtub water.

Conventionally, there is a water heater of this type having a function of reheating a bathtub using hot water of a hot water storage tank (see, for example, Patent Document 1).
FIG. 4 is a configuration diagram of the water heater described in Patent Document 1. As shown in the figure, this water heater is composed of a heat pump unit 200a and a hot water storage unit 10a including a hot water storage tank 21a and a bath heat exchanger 61a which is a water-to-water heat exchanger. The hot water storage tank 21a stores hot water heated by the heat pump unit 200a.
The bath heat exchanger 61a circulates the hot water in the hot water storage tank 21a to heat the hot water in the bathtub (not shown). That is, the hot water pumped from the upper part of the hot water storage tank 21a by the reheating pump 35a is guided to the bath heat exchanger 61a and returns to the hot water storage tank 21a after heat is dissipated.
On the other hand, in the bathtub water circuit 46a in which the bathtub, the bathtub water pump 34a, and the bath heat exchanger 61a are sequentially connected by the bath return pipe 44a and the bath going pipe 45a, the hot water pumped from the bathtub by the bathtub water pump 34a is , It is guided to the bath heat exchanger 61a in the hot water storage unit 10a via the bath return pipe 44a, and after heating, the bathtub is reheated by circulating back to the bathtub via the bath going pipe 45a, and the bathtub is kept warm. Will be done.
After that, in the bathtub, the bathtub water pump 34a is operated for a certain period of time at regular time intervals, the hot water of the bathtub is circulated to the hot water storage unit 10a side, and the bathtub temperature detection operation of detecting the water temperature of the bathtub by the return temperature detecting means 51a is performed. conduct. At this time, if the water temperature of the bathtub is equal to or lower than the predetermined temperature, the bath reheating is performed, and if the water temperature is equal to or higher than the predetermined temperature, the bath reheating is not performed.
FIG. 5 is a characteristic diagram showing an example of a water heater having this bath reheating function. The vertical axis shows the water temperature of the bathtub, and the horizontal axis shows the time. In the figure, Tu is the upper limit temperature for heat retention (reheating end temperature), and if the water temperature of the bathtub is equal to or higher than this temperature, the bath reheating is terminated. Further, Td is the lower limit temperature for heat retention (reheating start temperature), and if the water temperature of the bathtub is equal to or lower than the predetermined temperature Td, the bath reheating is started.
Further, in order to detect the water temperature of the bathtub, the bathtub temperature detection operation is performed at T1 intervals for a certain period of time. In the bathtub temperature detection operation, the bathtub water pump 34a of FIG. 4 is operated at T2 for a certain period of time, the hot water of the bathtub is circulated to the hot water storage unit 10a side, and the water temperature of the bathtub is detected by the return temperature detecting means 51a. At this time, the predetermined length of the bathtub water circuit 46a and T2 are set for a certain period of time so that the water temperature of the bathtub can be reliably detected even when the length of the bathtub water circuit 46a is long.

Japanese Patent No. 5686073

However, in the bathtub temperature detection operation according to Patent Document 1, the bathtub water pump 34a is operated for a certain period of time to detect the water temperature of the bathtub regardless of the length of the bathtub water circuit 46a between the bathtub and the hot water storage unit 10a.
In particular, when the outside air temperature is low as in winter, the bathtub water circuit 46a connected to the hot water storage unit 10a installed outdoors is cooled, and the water inside the pipe is also cooled.
As a result, even after the return temperature detecting means 51a detects the water temperature of the bathtub during the bathtub temperature detecting operation, the bathtub water pump 34a continues to operate, and the cooled water circulates in the bathtub water circuit 46a. , Cooled water continues to flow into the hot tub.
As a result, the water temperature of the bathtub is lowered, and there is a problem that the energy efficiency is lowered by increasing the number of times the bathtub water is heated.

The present invention solves the above-mentioned conventional problems, and when the water temperature of the bathtub is detected in the bathtub temperature detection operation, the bathtub water pump is stopped, the operation time of the bathtub water pump is shortened, and the energy efficiency is improved. The purpose is to provide a water heater with the aim of.

In order to solve the above-mentioned conventional problems, in the water heater of the present invention, a bathtub, a bathtub water pump for circulating hot water in the bathtub, and a bath heat exchanger for heating the hot water in the bathtub are sequentially circularly formed by water pipes. A connected bathtub water circuit, a return temperature detecting means for detecting the temperature of the hot water flowing through the water pipe from the bathtub to the bathtub water pump, and a control device for controlling operation and stop of the bathtub water pump. It has a hot water filling operation function for supplying the hot water to the bathtub, a bathtub temperature detection operation function for detecting the water temperature of the bathtub water in the bathtub, and a reheating operation function for reheating the bathtub water. The control device estimates the water temperature of the bathtub water, which decreases with the elapsed time from the end of the hot water filling operation or the end of the reheating operation, as an estimated bathtub water temperature, and at the end of the hot water filling operation or the above. When a predetermined time has elapsed from the end of the reheating operation, the bathtub temperature detection operation is started by operating the bathtub water pump, and after the bathtub temperature detection operation is started, the detection detected by the return temperature detecting means is started. When the water temperature reaches the estimated bathtub water temperature, the bathtub water pump is stopped to end the bathtub temperature detection operation .
Thereby, when the bathtub water pump starts operation, the bathtub water circulates in the bathtub water circuit from the bathtub toward the bath heat exchanger. As a result, the shorter the length of the bathtub water circuit, the shorter the time after the start of operation of the bathtub water pump can detect the bathtub water temperature.

In the water heater of the present invention, when the bathtub water pump starts operation, the shorter the length of the bathtub water circuit, the shorter the time after the start of operation of the bathtub water pump, the more the bathtub water temperature can be detected, so that the bathtub water temperature can be determined. The operation of the bathtub water pump can be stopped immediately after the detection.
As a result, when the length of the bathtub water circuit is short, the water of the low temperature bathtub water circuit flows into the hot bathtub, and the water temperature of the bathtub is lowered, especially in winter, as compared with the case where the length of the bathtub water circuit is long. This can be suppressed, the number of times the bathtub water is heated can be reduced, and energy efficiency can be improved.

Schematic block diagram of a water heater according to an embodiment of the present invention Characteristic diagram of bathtub water temperature in embodiment of the present invention Characteristic diagram of operation and return temperature of bathtub water pump in embodiment of the present invention Schematic block diagram of a conventional water heater Characteristic diagram of bathtub water temperature of conventional water heater

The first invention is from a bathtub water circuit in which a bathtub, a bathtub water pump for circulating hot water in the bathtub, and a bath heat exchanger for heating the hot water in the bathtub are sequentially connected in a ring shape by a water pipe, and the bathtub. A return temperature detecting means for detecting the temperature of the hot water flowing through the water pipe to the bathtub water pump and a control device for controlling the operation and stop of the bathtub water pump are provided, and the hot water is supplied to the bathtub. It has a hot water filling operation function, a bathtub temperature detecting operation function for detecting the temperature of the bathtub water in the bathtub, and a reheating operation function for reheating the bathtub water. When the water temperature of the bathtub water, which decreases depending on the time or the elapsed time from the end of the reheating operation, is estimated as the estimated bathtub water temperature, and a predetermined time elapses from the end of the hot water filling operation or the end of the reheating operation. After starting the bathtub temperature detection operation by operating the bathtub water pump and starting the bathtub temperature detection operation, when the detected water temperature detected by the return temperature detecting means becomes the estimated bathtub water temperature, the bathtub water The pump is stopped to end the bathtub temperature detection operation .

This causes the following effects.
When the bathtub water pump is put into operation, the bathtub water circulates in the bathtub water circuit from the bathtub to the bath heat exchanger. As a result, the shorter the length of the bathtub water circuit, the shorter the time after the start of operation of the bathtub water pump can detect the bathtub water temperature. Therefore, when the length of the bathtub water circuit is short, the operation of the bathtub water pump can be stopped immediately after the bathtub water temperature is detected.
Due to this action, when the length of the bathtub water circuit is short, the water in the cold bathtub water circuit flows into the hot bathtub, especially in winter, and the water temperature in the bathtub drops compared to when the length of the bathtub water circuit is long. It is possible to suppress this, reduce the number of times the bathtub water is heated, and improve energy efficiency.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to this embodiment.

FIG. 1 is a configuration diagram of a water heater according to an embodiment of the present invention.
In FIG. 1, the water heater 1A of the present embodiment includes a heat pump unit 21 and a hot water storage unit 27 as heating means. The heat pump unit 21 generates high-temperature water stored in the hot water storage tank 28 arranged in the hot water storage unit 27.
In this embodiment, a heat pump is used as the heating means, but the present invention is not limited to this, and for example, an electric heater may be installed inside the hot water storage tank 28 for heating.

Next, the configuration of the heat pump unit 21 will be described. In the heat pump unit 21, the compressor 22, the radiator 23, the expansion means 24, and the evaporator 25 are connected in an annular shape by a refrigerant pipe to form a refrigerant circuit 26.
As the refrigerant, for example, a non-azeotropic mixed refrigerant such as R407C, a pseudo-azeotropic mixed refrigerant such as R410A, or a single refrigerant such as carbon dioxide can be used.
Further, in the heat pump unit 21, the refrigerant compressed by the compressor 22 dissipates heat by the radiator 23, is depressurized by the expansion means 24, absorbs heat from the air by the evaporator 25, and is again compressed in the gas state. Inhaled in 22.
The compressor 22 and the expansion means 24 are controlled so that the temperature of the discharged refrigerant detected by the thermistor (not shown) provided on the discharge side of the compressor 22 is maintained at a preset temperature.
Further, the hot water in the hot water storage tank 28 flows into the radiator 23 by operating the circulation pump 37, exchanges heat with the refrigerant, returns to the hot water storage tank 28 again, and has a high temperature on the upper part of the hot water storage tank 28 in a laminated state. Water is stored.

Next, the configuration of the hot water storage unit 27 will be described.
As described above, the hot water storage unit 27 has a hot water storage tank 28, and a water supply pipe 29 for supplying low temperature water from a water supply source is connected to the bottom of the hot water storage tank 28, and the constant water supply pressure is constantly applied to the hot water storage tank 28. It depends.
Further, a hot water outlet pipe 30 for flowing out the high temperature water in the hot water storage tank 28 is connected to the upper part of the hot water storage tank 28, via a mixing valve 32 that mixes the high temperature water and the low temperature water from the water supply source. It is configured to be able to supply high temperature water to hot water supply terminals and the like.

Next, the reheating circuit 31 and the bathtub water circuit 41 will be described.
In the present embodiment, the hot water (bathtub water) in the bathtub 42 and the high-temperature water in the hot water storage tank 28 exchange heat with the bath heat exchanger 33 which is a bath heating means, and the bathtub water in the bathtub 42 is exchanged. It has a reheating function to reheat.
Therefore, the high temperature side circuit of the bath heat exchanger 33, the reheating pump 34, and the hot water storage tank 28 are sequentially connected by water pipes to form the reheating circuit 31. By operating the reheating pump 34, the high temperature water in the hot water storage tank 28 is conveyed to the high temperature side circuit of the bath heat exchanger 33, and the hot water after heat exchange is returned to the lower part of the hot water storage tank 28.
A bathtub water circuit 41 is configured in which the bathtub 42, the bathtub water pump 40 for circulating the bathtub water supplied to the bathtub, and the bath heat exchanger 33 for heating the bathtub water are sequentially connected in a ring shape by water pipes. By operating the bathtub water pump 40, the bathtub water in the bathtub 42 is conveyed to the low temperature side circuit of the bath heat exchanger 33, and the high temperature water after heat exchange is returned to the bathtub 42.
At this time, the return temperature detecting means 44 arranged between the bathtub 42 and the bathtub water pump 40 detects the water temperature of the bathtub 42 conveyed from the bathtub 42 to the low temperature side circuit of the bath heat exchanger 33. On the other hand, after heat exchange, the temperature of the high temperature water conveyed from the low temperature side circuit of the bath heat exchanger 33 to the bath 42 is the reheating temperature detecting means arranged downstream of the low temperature side circuit of the bath heat exchanger 33. It is detected at 43.

The hot water pouring circuit 11 is a circuit that conveys the high-temperature water of the hot water storage tank 28 to the bathtub 42 via the bathtub water circuit 41 to fill the hot water. The pouring circuit 11 includes a bathtub water mixing valve 39 that mixes the high temperature water of the hot water storage tank 28 and the low temperature water from the water supply source, a pouring temperature detecting means 35 that detects the temperature of the hot water that flows out after mixing, and a pouring water. A bathtub water pouring valve 36 for opening and closing the circuit of the circuit 11 is provided in order.

Further, in the bathroom where the bathtub 42 is arranged, a remote control device 51 which is an operation means capable of operating the water heater 1A and which is a temperature setting means for setting the heat retention temperature of the bathtub water in the bathtub 42 is provided. Once installed, the remote controller 51 is operated to set the water temperature of the bathtub 42, fill the bathtub with hot water, and perform a trial run operation after the installation work.

Further, the water heater 1A of the present embodiment also has a control device 50 that receives information from the detection means and the remote control device 51, makes a determination, and commands each control device. The control device 50 is composed of a microcomputer and its electronic control components, and sends a command to equipment (such as a reheating pump 34 and a bathtub water pump 40) constituting the hot water storage unit 27.
The control device 50 has a function of estimating the current water temperature of the bathtub 42 in consideration of the elapsed time (standby time) from the end of filling the bathtub with hot water or the end of reheating. When the bathtub water pump 40 operates and the detected water temperature of the return temperature detecting means 44 becomes the estimated bathtub water temperature (for example, the estimated water temperature of the bathtub 42-1K), the control device 50 detects the return temperature of the bathtub water. It is determined that the means 44 has been reached.
That is, when the predetermined standby time elapses, the control device 50 operates the bathtub water pump for the hot water temperature detection time, but estimates the estimated bathtub water temperature from the standby time and the water temperature detected before the start of this standby time, and returns. When the estimated bathtub water temperature is detected by the temperature detecting means 44, the hot water temperature detection time is terminated and the bathtub water pump 40 is stopped. The waiting time is not limited to the predetermined time ΔL set to a constant value.

The operation and operation of the water heater configured as described above will be described below.
First, the hot water filling operation will be described. If the user operates the remote controller 51 to start the hot water filling operation, or if the hot water filling operation is reserved in advance, the hot water filling operation is started at the set time. When the hot water filling operation is started, the bathtub water injection valve 36 is opened, and the high temperature water from the hot water storage tank 28 is mixed by the bathtub water mixing valve 39 so as to reach a set temperature and supplied to the bathtub 42.
In the hot water filling operation, the water temperature of the bathtub 42 mixed by the bathtub water injection valve 36 may be several degrees higher than the temperature of the hot water set by the remote controller 51. This is because the hot water mixed by the bathtub water pouring valve 36 dissipates heat when flowing through the pipe until it reaches the bathtub 42, and there is a possibility that the temperature drops when the hot water is poured into the bathtub 42. Because. Therefore, by setting the temperature of the hot water mixed by the bathtub water injection valve 36 to be higher than the set temperature, it is possible to perform the hot water filling operation in consideration of heat dissipation in the piping.
The amount of hot water filled is detected by a flow rate sensor (not shown) in the hot water pouring circuit 11, and when the set amount of hot water is detected by the flow rate sensor, the bathtub water pouring valve 36 closes and the hot water filling operation ends. ..

Next, a bathtub temperature detection operation for detecting the temperature of the bathtub 42 will be described.
After the hot water filling operation is completed, the bathtub temperature detection operation is performed. In the bathtub temperature detection operation, the bathtub water pump 40 is operated every time ΔL elapses after the end of the hot water filling operation, and the bathtub water in the bathtub 42 is circulated to the bathtub water circuit 41 to detect the return temperature. At 44, the water temperature of the bathtub 42 in the bathtub 42 is detected. For example, if the predetermined time ΔL is set to 15 minutes, the bathtub water pump 40 is operated every 15 minutes after the end of the hot water filling operation to detect the temperature.
Here, as a result of detecting the water temperature of the bathtub 42 in the bathtub 42 by operating the bathtub water pump 40 for a predetermined time ΔW (for example, 45 seconds) after the predetermined time ΔL has elapsed, the bathtub 42 in the bathtub 42. When the water temperature of the water becomes equal to or lower than the predetermined temperature Td (reheating start temperature), the reheating operation is started. That is, the reheating pump 34 and the bath water pump 40 are operated, and the high temperature water in the hot water storage tank 28 and the bath water in the bath 42 exchange heat in the bath heat exchanger 33, and the bath water in the bath 42. Is reheated. Then, when the water temperature of the bathtub 42 in the bathtub 42 reaches the set temperature Tu (reheating end temperature), the reheating operation is stopped and the reheating operation is completed.

FIG. 2 is a characteristic diagram of the bathtub water temperature in the bathtub temperature detection operation. As shown in the conventional characteristics of FIG. 2, when the first predetermined time ΔL has elapsed after the reheating operation is completed, the bathtub water pump 40 is first operated for a predetermined time ΔW to form the bathtub 42 in the bathtub 42. Detect water temperature. At this time, since the water temperature of the bathtub 42 in the bathtub 42 has not yet fallen below the predetermined temperature Td, after the second predetermined time ΔL has elapsed, the bathtub water pump 40 is operated again to operate the bathtub water pump 40 in the bathtub 42. The water temperature of the bathtub 42 is detected.
As a result, since the temperature is below the predetermined temperature Td this time, the operation of the reheating pump 34 is also started, and the reheating operation of the bathtub water in the bathtub 42 is started by the operation of the reheating pump 34 and the bathtub water pump 40. ..
Then, when the water temperature of the bathtub 42 in the bathtub 42 reaches the set temperature Tu, the heating operation is terminated.
On the other hand, as shown in the characteristics of the present invention in FIG. 2, when the first predetermined time ΔL has elapsed after the end of the reheating operation, the bathtub water pump 40 is operated and estimated by the return temperature detecting means 44. When the bathtub water temperature is detected, the hot water temperature detection time ends and the bathtub water pump is stopped. FIG. 2 shows that the hot water temperature detection time is shorter than the predetermined time ΔW and the operating time ΔWb.

FIG. 3 shows the operation of the bathtub water pump and the characteristics of the return temperature in the return temperature detecting means.
FIG. 3A shows the operation of the bathtub water pump 40 in the bathtub water circuit 41 and the return temperature of the bathtub 42 in the return temperature detecting means 44. In particular, when the outside air temperature is low as in winter and the bathtub water pump 40 is stopped, the water temperature Tp in the return temperature detecting means 44 in the hot water storage unit 27 installed outdoors is sent to the surrounding outside air. Due to the heat radiation, the temperature is lower than the predetermined temperature Tb of the bathtub 42 installed in the room (Tp <Tb).
Here, when the bathtub water pump 40 starts operation at time to, the bathtub water circulates in the bathtub water circuit 41 from the bathtub 42 toward the bath heat exchanger 33. When the hot bathtub water reaches the return temperature detecting means 44 from the bathtub 42 after the time Δt (return temperature detection time) when the bathtub water from the bathtub 42 reaches the return temperature detecting means 44 from the time to. The return temperature detecting means 44 detects a change in the bathtub water temperature from the water temperature Tp to a predetermined temperature Tb.
At this time, the return temperature detection time Δt is shorter in the case of the short pipe (Δt1) than in the case of the bathtub water circuit 41 with the long pipe (Δt2) (Δt1 <Δt2). That is, the shorter the length of the bathtub water circuit 41, the shorter the time after the start of operation of the bathtub water pump 40, the shorter the time it is possible to detect the bathtub water temperature.

FIG. 3B shows the relationship between the operating time ΔW of the bathtub water pump 40 and the return temperature detection time Δt. Conventionally, the operating time of the bathtub water pump 40 has been set to a predetermined time ΔWo (for example, 45 seconds). Therefore, the bathtub water pump 40 is operated for a predetermined time ΔWo regardless of the return temperature detection time Δt in the return temperature detecting means 44.
On the other hand, in the present invention, the shorter the time Δt at which the detected water temperature of the return temperature detecting means 44 reaches the bathtub water temperature, the shorter the operating time ΔW of the bathtub water pump 40. That is, the shorter the length of the bathtub water circuit 41, the shorter the bathtub water temperature can be detected after the start of operation of the bathtub water pump 40. Therefore, when the length of the bathtub water circuit 41 is short, the bathtub water temperature can be detected immediately after the detection. The operation of the bathtub water pump 40 can be stopped.
Due to these actions, in FIG. 2, when the length of the bathtub water circuit 41 is short, the operating time ΔWa of the bathtub water pump 40 having the conventional characteristics can be changed to the operating time ΔWb having the characteristics of the present invention. That is, when the length of the bathtub water circuit 41 is short, the water of the low temperature bathtub water circuit 41 flows into the high temperature bathtub 42, and the water of the bathtub 42 is particularly in winter, as compared with the case where the length of the bathtub water circuit 41 is long. It is possible to suppress the decrease in water temperature, reduce the number of times the bathtub water is heated, and improve energy efficiency.

As described above, in the present embodiment, the bathtub water circuit 41 includes a return temperature detecting means 44 disposed between the bathtub 42 and the bathtub water pump 40 to detect the water temperature, and the return temperature detecting means 44. The shorter the time it takes for the detected water temperature to reach the bathtub water temperature, the shorter the operating time of the bathtub water pump 40.
As a result, when the bathtub water pump 40 starts operation, the bathtub water circulates in the bathtub water circuit 41 from the bathtub 42 toward the bath heat exchanger 33. As a result, the shorter the length of the bathtub water circuit 41, the shorter the time after the start of operation of the bathtub water pump 40, the shorter the time it is possible to detect the bathtub water temperature. Therefore, when the length of the bathtub water circuit 41 is short, the operation of the bathtub water pump 40 can be stopped immediately after the bathtub water temperature is detected.
Due to these actions, when the length of the bathtub water circuit 41 is short, the water of the low temperature bathtub water circuit 41 flows into the high temperature bathtub 42, especially in winter, as compared with the case where the length of the bathtub water circuit 41 is long. It is possible to suppress a decrease in the water temperature of the bathtub 42, reduce the number of times the bathtub water is heated, and improve energy efficiency.

Since the present invention can reduce the number of times the bath water is heated for heat retention and improve energy efficiency, a hot water storage type heat pump that stores the generated hot water in a hot water storage tank from an instant heating type combustion type water heater that immediately uses the generated hot water. It is especially useful for various water heaters such as water heaters and electric water heaters.

1A Hot water supply machine 11 Hot water injection circuit 21 Heat pump unit 22 Compressor 23 Radiator 24 Expansion means 25 Evaporator 26 Refrigerator circuit 27 Hot water storage unit 28 Hot water storage tank 29 Water supply pipe 30 Hot water supply pipe 31 Reheating circuit 32 Mixing valve 33 Bath heat exchanger 34 Reheating pump 35 Pouring temperature detecting means 36 Bathtub water pouring valve 37 Circulation pump 39 Bathtub water mixing valve 40 Bathtub water pump 41 Bathtub water circuit 42 Bathtub 43 Reheating temperature detecting means 44 Return temperature detecting means 50 Control device 51 Remote control device

Claims (1)

A bathtub, a bathtub water pump that circulates the hot water of the bathtub, and a bathtub water circuit in which the bath heat exchanger that heats the hot water of the bathtub is sequentially connected in a ring shape by a water pipe.
A return temperature detecting means for detecting the temperature of the hot water flowing through the water pipe from the bathtub to the bathtub water pump, and a return temperature detecting means .
It is equipped with a control device for controlling the operation and stop of the bathtub water pump.
A hot water filling operation function that supplies the hot water to the bathtub, and
The bathtub temperature detection operation function that detects the water temperature of the bathtub water in the bathtub, and
With the reheating operation function to reheat the bathtub water
Have,
In the control device,
The water temperature of the bathtub water, which decreases with the elapsed time from the end of the hot water filling operation or the end of the reheating operation, is estimated as the estimated bathtub water temperature.
When a predetermined time has elapsed from the end of the hot water filling operation or the end of the reheating operation, the bathtub water pump is operated to start the bathtub temperature detection operation.
When the detected water temperature detected by the return temperature detecting means reaches the estimated bathtub water temperature after the bathtub temperature detection operation is started, the bathtub water pump is stopped to end the bathtub temperature detection operation. A water heater featuring.

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