JP7529541B2 - Hot water supply equipment - Google Patents

Description

The present invention relates to a hot water supply device that includes a hot water heater, a water supply passage that supplies water to the hot water heater, a hot water outlet passage that supplies hot water discharged from the hot water heater, a hot water tap device connected to the downstream end of the hot water outlet passage, a water volume sensor provided in the water supply passage or the hot water outlet passage, and a water volume servo provided in the water supply passage or the hot water outlet passage.

Conventionally, this type of hot water supply device is known to be equipped with a heater that heats the water supplied to the hot water tap through the hot water outlet passage and a water temperature sensor that detects the temperature of the water supplied to the hot water tap through the hot water outlet passage upstream of the heater in order to prevent cold water from being discharged when the hot water tap is first opened. If the water temperature detected by the water temperature sensor is lower than a predetermined temperature when the hot water tap is opened, the heater is energized to heat the water until the water temperature detected by the water temperature sensor reaches or exceeds the predetermined temperature, thereby performing instant hot water control (see, for example, Patent Document 1).

However, with this type of device, when the hot water tap is opened widely, the amount of water increases, and the heating capacity of the heater cannot keep up, so the temperature of the hot water coming out of the hot water tap becomes lower than the specified temperature. In this case, it is possible to use a heater with a higher heating capacity, but this would require a large amount of space for the heater, leading to a larger hot water tap and higher costs.

JP 2017-36877 A

In view of the above, the present invention aims to provide a hot water supply device that can provide an instant hot water function that quickly raises the temperature of the hot water when the hot water tap is opened, without using a heater with a large heating capacity.

In order to solve the above problems, the present invention provides a hot water supply device comprising a water heater, a water supply passage for supplying water to the water heater, a hot water outlet passage for supplying hot water discharged from the water heater, a hot water tap connected to the downstream end of the hot water outlet passage, a water volume sensor provided in the water supply passage or the hot water outlet passage, a water volume servo provided in the water supply passage or the hot water outlet passage, and a control means, wherein the hot water tap is provided with a heater for heating water supplied to the hot water tap via the hot water outlet passage, and a water temperature sensor for detecting the temperature of the water supplied to the hot water tap via the hot water outlet passage upstream of the heater, and the control means performs instant hot water control by passing current through the heater to heat the water until the water temperature detected by the water temperature sensor becomes equal to or higher than the predetermined temperature when the hot water tap is opened, and wherein under conditions in which the temperature of hot water discharged from the hot water tap does not rise to the predetermined temperature even when the heating amount of the heater is maximized during instant hot water control, water volume throttling control is performed by the water volume servo.

According to the above premise , when the hot water temperature from the hot water tap device does not rise to a predetermined temperature even when the heating amount of the heater is maximized by opening the hot water tap device widely, the water volume throttling control is executed and the hot water temperature rises quickly. Therefore, the hot water instantaneous function can be obtained without using a heater with a large heating capacity, and the hot water tap device can be avoided from becoming larger and more expensive.

Here , the present invention is characterized in that , under the above premise , during instant hot water control, the heating amount of the heater required to raise the temperature of hot water from the hot water tap to the above-mentioned predetermined temperature is calculated as a target heating amount from the water amount detected by the water amount sensor and the water temperature detected by the water temperature sensor, and when this target heating amount exceeds the maximum heating amount of the heater, it is determined that the above-mentioned condition is met, and water amount throttling control is executed. Note that , in the water amount throttling control, the water amount at which the temperature of hot water from the hot water tap becomes the above-mentioned predetermined temperature with the maximum heating amount of the heater is calculated as a target throttling water amount, and the water amount is throttled by the water amount servo so that the water amount detected by the water amount sensor becomes the target throttling water amount.

In addition, if the target heating amount falls below the maximum heating amount of the heater, it is desirable to adjust the heating amount of the heater to the target heating amount without performing water throttling control. In this way, even if water throttling control is not performed, the temperature of the hot water coming out of the hot water tap device can be raised and maintained at the above-mentioned predetermined temperature.

Incidentally, when a water heater is equipped with a burner and a heat exchanger heated by the combustion of the burner, the combustion of the burner is not started unless the amount of water detected by the water volume sensor reaches a predetermined lower limit amount in order to prevent the heat exchanger from burning dry. Here, the instant hot water control is a control performed to prevent cold water from being discharged from the hot water tap until the hot water heated by the heat exchanger reaches the hot water tap. Therefore, unless the amount of water detected by the water volume sensor reaches a predetermined lower limit amount at which the combustion of the burner starts, it is useless to perform the instant hot water control. Therefore, the present invention is characterized in that the execution of the instant hot water control is prohibited unless the amount of water detected by the water volume sensor reaches a predetermined lower limit amount at which the combustion of the burner starts .

FIG. 1 is an explanatory diagram illustrating a hot water supply device according to an embodiment of the present invention. FIG. 4 is a flow chart showing the contents of instant hot water control performed by a control unit of the hot water supply device according to the embodiment.

The hot water supply device according to an embodiment of the present invention shown in FIG. 1 includes a hot water heater 1, a water supply passage 2 that supplies water to the hot water heater 1, a hot water outlet passage 3 that supplies hot water discharged from the hot water heater 1, a hot water tap 4 connected to the downstream end of the hot water outlet passage 3, a water volume sensor 5 provided in the water supply passage 2, a water volume servo 6 also provided in the water supply passage 2, and a controller 7 as a control means. A remote control 71 is connected to the controller 7. The water volume sensor 5 may be provided in the hot water outlet passage 3, and the water volume servo 6 may be provided in the hot water outlet passage 3.

In this embodiment, the water heater 1 is equipped with a burner 11 and a heat exchanger 12 that is heated by the combustion of the burner 11. A water supply passage 2 is connected to the inlet side of the heat exchanger 12, and a hot water outlet passage 3 is connected to the outlet side of the heat exchanger 12. A water supply temperature sensor 8 that detects the temperature of the water flowing in the water supply passage 2 is provided in the water supply passage 2, and a hot water outlet temperature sensor 9 that detects the temperature of the hot water flowing in the hot water outlet passage 3 is provided in the hot water outlet passage 3.

The controller 7 controls hot water supply based on detection signals from the water volume sensor 5, the water supply temperature sensor 8, and the hot water outlet temperature sensor 9. In hot water supply control, first, when the water volume detected by the water volume sensor 5 becomes equal to or exceeds a predetermined lower limit water volume (e.g., 2.5 L/min) by opening the hot water tap 4, the burner 11 is ignited to start combustion. Then, the amount of combustion of the burner 12 required to discharge hot water at a predetermined set hot water outlet temperature set by the remote control 71 is calculated as a target combustion amount from the water volume detected by the water volume sensor 5 and the water temperature detected by the water supply temperature sensor 8, and feedforward control is performed to control the amount of combustion of the burner 12 to the target combustion amount, and further, feedback control is performed to control the amount of combustion of the burner 12 so that the temperature detected by the hot water outlet temperature sensor 9 becomes the set hot water outlet temperature. In addition, if the amount of water is too much and the temperature detected by the outlet hot water temperature sensor 9 does not rise to the set hot water outlet temperature even when the amount of combustion of the burner 11 is maximized, the water volume is reduced by the water volume servo 6 until the temperature detected by the outlet hot water temperature sensor 9 rises to the set hot water outlet temperature.

However, after hot water supply is stopped, the hot water remaining in the hot water outlet passage 3 cools down. When hot water supply is resumed by opening the hot water tap 4, the cold water remaining in the hot water outlet passage 3 is discharged from the hot water tap 4, causing discomfort to the user.

Therefore, in this embodiment, the hot water tap 4 is provided with a heater 41 that heats the water supplied to the hot water tap 4 through the hot water outlet passage 3, and a water temperature sensor 42 that detects the temperature of the water supplied to the hot water tap 4 through the hot water outlet passage 3 upstream of the heater 41. When the hot water tap 4 is opened, if the water temperature detected by the water temperature sensor 42 is lower than a predetermined temperature, the controller 7 performs instant hot water control by passing electricity through the heater 41 to heat the water until the water temperature detected by the water temperature sensor 42 reaches or exceeds the predetermined temperature. Note that this predetermined temperature is set lower than the above-mentioned set hot water outlet temperature, for example, to about 30°C. However, since some users may feel that 30°C is too low, it is desirable to be able to change the setting of the predetermined temperature with the remote control 71.

The instant hot water control will be described in detail below with reference to FIG. 2. Instant hot water control is started when it is determined in STEP 1 that the water volume W detected by the water volume sensor 5 is equal to or greater than the predetermined lower limit water volume YWmin at which combustion of the burner 11 begins, and when it is determined in STEP 2 that the water temperature T detected by the water temperature sensor 42 is lower than the predetermined temperature YT. If it is determined in STEP 1 that W<YWmin, or if it is determined in STEP 2 that T≧YT, the process proceeds to STEP 3, where the heater 41 is turned off (power supply to the heater 41 is stopped), and the process returns to STEP 1. Therefore, when the water temperature T detected by the water temperature sensor 42 is lower than the predetermined temperature YT, instant hot water control is performed until the water temperature T detected by the water temperature sensor 42 becomes equal to or greater than the predetermined temperature YT.

In the instant hot water control, first, in STEP 4, the heating amount of the heater 41 required to raise the temperature of the hot water outlet from the hot water tap 4 to a predetermined temperature YT is calculated as the target heating amount Qcom from the water volume W detected by the water volume sensor 5 and the water temperature T detected by the water temperature sensor 42. Next, proceed to STEP 5 to determine whether the target heating amount Qcom exceeds the maximum heating amount YQmax of the heater 41. If Qcom≦YQmax, proceed to STEP 6 to turn on the heater 41 (power is applied to the heater 41) and adjust the heating amount of the heater 41 to the target heating amount Qcom, and then return to STEP 1. This allows the temperature of the hot water outlet from the hot water tap 4 to be raised and maintained at the predetermined temperature YT.

If it is determined in STEP 5 that Qcom > YQmax, water volume throttling control is executed to throttle the water volume using the water volume servo 6. In water volume throttling control, first in STEP 7, the water volume at which the hot water outlet temperature from the hot water tap 4 becomes a predetermined temperature YT at the maximum heating amount YQmax of the heater 41 is calculated as the target throttle water volume Wcom based on the water temperature T detected by the water temperature sensor 42. Next, the process proceeds to STEP 8, where the water volume is throttled using the water volume servo 6 so that the water volume W detected by the water volume sensor 5 becomes the target throttle water volume Wcom, and further in STEP 9 the heater 41 is turned on and the heating amount of the heater 41 is adjusted to the maximum heating amount YQmax, and then the process returns to STEP 1.

According to the instant hot water control of this embodiment, when the hot water tap 4 is opened widely and the heating amount of the heater 41 is set to the maximum heating amount YQmax, if the temperature of the hot water from the hot water tap 4 does not rise to the predetermined temperature YT, the water volume throttling control is executed and the temperature of the hot water is raised quickly. Therefore, the instant hot water function can be obtained without using a heater with a large heating capacity, and the size and cost of the hot water tap 4 can be avoided.

In addition, a water temperature sensor that detects the temperature of the hot water coming out of the hot water tap 4 can be provided downstream of the heater 41, and even if the amount of heat from the heater 41 is set to the maximum amount of heat YQmax, water throttling control can be executed when the temperature detected by the water temperature sensor does not rise to the predetermined temperature YT. Furthermore, when performing water throttling control, it is possible to throttle the water volume by feedback control so that the temperature detected by the water temperature sensor becomes the predetermined temperature YT. However, this requires a water temperature sensor, which increases costs.

In contrast, in this embodiment, when the target heating amount Qcom calculated as described above exceeds the maximum heating amount YQmax of the heater 41, it is determined that even if the heating amount of the heater 41 is set to the maximum heating amount YQmax, the temperature of the hot water outlet from the hot water tap 4 will not rise to the specified temperature YT, and water volume throttling control is performed. Furthermore, when performing water volume throttling control, the target throttle water volume Wcom is calculated as described above, and the water volume is throttled by the water volume servo 6 to the target throttle water volume Wcom, thereby raising the temperature of the hot water outlet from the hot water tap 4 to the specified temperature YT by feedforward control. This eliminates the need for a water temperature sensor to detect the temperature of the hot water outlet from the hot water tap 4, and avoids increased costs.

Incidentally, instant hot water control is a control performed to prevent cold water from being discharged from the hot water tap 4 until the hot water heated by the heat exchanger 12 reaches the hot water tap 4. Therefore, unless the water volume W detected by the water volume sensor 5 is equal to or greater than the predetermined lower limit water volume YWmin at which the burner 11 starts to burn, there is no point in performing instant hot water control. Therefore, in this embodiment, if W<YWmin, the process returns to STEP 1 via STEP 3 from STEP 1, and execution of instant hot water control from STEP 4 onwards is prohibited.

Although the embodiment of the present invention has been described above with reference to the drawings, the present invention is not limited thereto. For example, the water heater 1 in the above embodiment is equipped with a burner 11 and a heat exchanger 12 that is heated by the combustion of the burner 11, but it may also be a hot water storage type equipped with a hot water storage tank. In this case, in STEP 1 of FIG. 2, when the detected water volume W of the water volume sensor 5 becomes equal to or greater than a predetermined threshold value (e.g., 1.5 L/min), it is determined that the hot water tap 4 has been opened, and the process proceeds to STEP 2. This threshold value may be changeable using the remote control 71.

1...water heater, 11...burner, 12...heat exchanger, 2...water supply passage, 3...hot water outlet passage, 4...hot water tap, 41...heater, 42...water temperature sensor, 5...water volume sensor, 6...water volume servo, 7...controller (control means).

Claims (4)

A hot water supply device comprising: a water heater; a water supply passage for supplying water to the water heater; a hot water outlet passage for supplying hot water discharged from the water heater; a hot water tap device connected to a downstream end of the hot water outlet passage; a water volume sensor provided in the water supply passage or the hot water outlet passage; a water volume servo provided in the water supply passage or the hot water outlet passage; and a control means;
The hot water tap device is provided with a heater for heating water supplied to the hot water tap device through the hot water outlet passage, and a water temperature sensor for detecting the temperature of the water supplied to the hot water tap device through the hot water outlet passage upstream of the heater,
The control means performs instant hot water control by passing current through the heater to heat the water when the water temperature detected by the water temperature sensor is lower than a predetermined temperature when the hot water tap device is opened, until the water temperature detected by the water temperature sensor becomes equal to or higher than the predetermined temperature,
In the instant hot water control, if the temperature of the hot water from the hot water tap does not rise to a predetermined temperature even when the heating amount of the heater is maximized, a water volume throttling control is executed to throttle the water volume with a water volume servo.
This hot water supply device is characterized in that, during instant hot water control, the amount of heat generated by the heater required to raise the temperature of the hot water outlet from the hot water tap to the specified temperature is calculated as a target amount of heat from the water volume detected by the water volume sensor and the water temperature detected by the water temperature sensor, and when this target amount of heat exceeds the maximum amount of heat from the heater, it is determined that the above conditions are met and water volume throttling control is executed . The hot water supply device of claim 1, characterized in that in the water volume throttling control, the water volume at which the hot water outlet temperature from the hot water tap device will be at the specified temperature with the maximum heating amount of the heater is determined as a target throttling water volume, and the water volume is throttled by the water volume servo so that the water volume detected by the water volume sensor becomes the target throttling water volume. 3. The hot water supply apparatus according to claim 1 , wherein, when the target heating amount falls below a maximum heating amount of the heater, the water amount throttling control is not performed, and the heating amount of the heater is adjusted to the target heating amount. A hot water supply device comprising: a hot water heater having a burner and a heat exchanger heated by combustion of the burner; a water supply passage for supplying water to the hot water heater; a hot water outlet passage for supplying hot water discharged from the hot water heater; a hot water tap device connected to a downstream end of the hot water outlet passage; a water volume sensor provided in the water supply passage or the hot water outlet passage; a water volume servo provided in the water supply passage or the hot water outlet passage; and a control means;
The hot water tap device is provided with a heater for heating water supplied to the hot water tap device through the hot water outlet passage, and a water temperature sensor for detecting the temperature of the water supplied to the hot water tap device through the hot water outlet passage on the upstream side of the heater,
The control means performs instant hot water control by passing current through the heater to heat the water when the water temperature detected by the water temperature sensor is lower than a predetermined temperature when the hot water tap device is opened, until the water temperature detected by the water temperature sensor becomes equal to or higher than the predetermined temperature,
In the instant hot water control, if the temperature of the hot water from the hot water tap does not rise to a predetermined temperature even when the heating amount of the heater is maximized, a water volume throttling control is executed to throttle the water volume with a water volume servo.
The hot water supply device is further characterized in that the execution of the instant hot water control is prohibited unless the amount of water detected by the water amount sensor reaches or exceeds a predetermined lower limit water amount at which the burner starts combustion.

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