JP3172612B2 - Combined water heater and method for stabilizing the temperature of refilled hot water - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combined water heater provided with a means for stabilizing a hot water temperature at the time of hot water re-starting and a method for stabilizing the hot water temperature at the hot water re-starting time.

[0002]

2. Description of the Related Art As is well known, a combined water heater having a hot water supply function and other functions such as reheating of a bath is widely used. This type of combined water heater has a hot water combustion system in the appliance,
For example, a reburning combustion system such as a bath is provided. The hot water supply combustion system burns a hot water supply burner, heats a hot water supply heat exchanger, turns water passing through the hot water supply heat exchanger into hot water, and supplies the hot water to a desired hot water supply place such as a kitchen.

[0003] On the other hand, the reburning combustion system is provided with a reburning burner, the reburning burner is heated to heat the reburning heat exchanger, and the circulating water flow of the bathtub hot water passing through the reburning heat exchanger is heated. It reheats hot water. This type of combined water heater is provided with individual or shared combustion fans for supplying and exhausting air for feeding air to the hot water supply burner and the reheating burner.

[0004]

In this type of combined water heater, when the hot water burner is burned and the hot water in the hot water supply heat exchanger is used, and then the faucet is closed to stop tapping the hot water, the hot water supply burner stops burning. Then, the inside of the hot water supply heat exchanger is filled with hot water. During this hot water supply stoppage, if reheating of the bath water is performed by the combustion of the reburning burner of the reburning combustion system of another function, in the appliance using a common combustion fan, the air is turned by the rotation of the combustion fan on the hot water supply burner side. Is supplied to the hot water supply heat exchanger, and the temperature of the hot water in the hot water supply heat exchanger decreases.

[0005] Even in appliances in which separate combustion fans are provided for the hot water supply burner and the additional heating burner, when the additional heating operation is performed while the hot water supply is stopped, the combustion on the hot water supply burner side is performed to prevent recirculation of exhaust gas. Since the fan also rotates, the air from the combustion fan passes through the hot water supply heat exchanger, so that a cooling action occurs and the temperature of the hot water in the hot water supply heat exchanger decreases. As described above, when the temperature of the hot water in the hot water supply heat exchanger is cooled by the operation of the reheating combustion system, the next time the faucet is opened and hot water is re-discharged, the cooled hot water in the hot water supply heat exchanger has a low temperature. There is a problem that the temperature of the hot water at the time of re-starting hot water becomes large, such as hot water at a set temperature due to the combustion of the hot water supply burner after the hot water is supplied, and the user of the hot water feels unpleasant.

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to supply hot water in a hot water supply heat exchanger by rotation of a combustion fan accompanying combustion of other functions such as a reheating combustion system. It is an object of the present invention to provide a combined water heater that is cooled and does not cause a large fluctuation in hot water temperature at the time of hot water re-starting, and a method for stabilizing the hot water temperature again.

[0007]

The present invention is configured as follows to achieve the above object. That is, a first aspect of the present invention relates to a combined water heater having a hot water supply heat exchanger heated by a hot water supply burner and a combustion system of another function burner other than hot water supply. And a backup heating means for adding the absorbed heat to the hot water supply heat exchanger during operation stop. Further, a second invention provides a method for stabilizing the re-starting hot water temperature of a combined hot water supply apparatus having a hot water supply heat exchanger heated by a hot water supply burner and a combustion system of a burner other than the hot water supply. When the other-function burner is burning while the operation is stopped, the heat accompanying the combustion of the other-function burner is absorbed, and the absorbed heat is added to the hot water supply heat exchanger. It is configured to suppress cooling of hot water in the exchanger.

[0008]

In the present invention having the above construction, when the hot water supply from the hot water supply heat exchanger is stopped and the burner of the other function burns, the heat exchanger receives the wind of the combustion fan and radiates heat.
At this time, the temperature of the hot water in the heat exchanger is about to decrease. At this time, the heat generated by the combustion of the other function burner is added to the hot water supply heat exchanger by the operation of the backup heating means. Only by the heating of the backup heating means, the heat is supplemented, the cooling of the hot water in the hot water supply heat exchanger is suppressed, and the hot water having a stable hot water temperature with little fluctuation in the hot water temperature at the next hot water re-discharge is possible.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of a combined water heater according to the present invention. In this figure, this combined hot water supply device is provided with a hot water supply function and a reheating function, and a hot water supply heat exchanger 2 is disposed above a hot water supply burner 1 on a hot water supply function side, and is provided below a hot water supply burner 1. Is provided with a combustion fan 3 for air supply and exhaust.

At the inlet side of the hot water supply heat exchanger 2, a water supply pipe 4 is provided.
The water supply pipe 4 is provided with a water supply temperature sensor 5 for detecting a water supply temperature and a water amount sensor 6 for detecting a water supply amount. A hot water supply pipe 7 is connected to an outlet side of the hot water supply heat exchanger 2, and the hot water supply pipe 7 guides hot water of the hot water supply heat exchanger 2 to a desired place such as a kitchen. Hot water supply pipe 7 is provided with hot water temperature sensor 8 for detecting hot water temperature. The hot water supply heat exchanger 2 is provided with a bypass passage 10 in parallel, and the hot water flowing out of the hot water supply heat exchanger 2 mixes with the water flowing through the bypass passage 10 and flows out of the faucet 9 of the hot water supply pipe 7. It is supposed to be.

A reburning burner 12 is provided below the reburning heat exchanger 11 on the reheating function side, and air is sucked into the reburning burner 12 by the combustion fan 3 common to the hot water supply side. Alternatively, it is supplied in a push-in type (not shown).

The inlet side of the reheater 11 is connected to a pipe 13
Is connected to the discharge side of the circulation pump 14 through the circulation pump
The suction side of 14 is connected to a bathtub 16 via a return pipe 15. Further, an outgoing pipe 17 is connected to an outlet side of the reheating heat exchanger 11, and a distal end side of the outgoing pipe 17 is connected to a bathtub 16. The return pipe 15, the circulation pump 14, the reheating heat exchanger 11, and the outgoing pipe
The pipeline reaching the bathtub 16 via 17 constitutes a reheating circulation pipeline 18.

The upper side of the reheater 11 has an exhaust port.
40, the exhaust pipe 20 is connected to this exhaust port 40,
The exhaust gas from the reburning burner 12 is discharged to the outside through the exhaust stack 20.

The present embodiment is characterized in that the backup heating means 21 is provided between the hot water supply function side and the reheating function side.
That is, This backup heating means 21
The exhaust pipe 20 is surrounded by an air supply pipe 22 and is constituted by a double pipe of exhaust and air supply. Further, the lower part of the air supply pipe 22 is formed in a case shape, and the reburning heat exchanger 11 and the reburning burner 12 are burners. The case 19 is enclosed, and the outlet side is made cylindrical so as to face the suction port of the combustion fan 3, and a passage from the air supply pipe 22 to the combustion fan 3 is formed as an air supply passage 23. A configuration in which the air introduced from the trachea 22 is brought into contact with the exhaust stack 20, the reheating heat exchanger 11 and the burner case 19 to absorb the heat of the reheating combustion system and guide the warmed air to the suction side of the combustion fan 3; Has become.

The operation of the hot water supply burner 1 and the reburning burner 12 according to the present embodiment is controlled by a control device (not shown).

This embodiment is constructed as described above. Next, the operation of the backup heating means 21 for stabilizing the temperature of the hot water is described. During hot water supply operation, hot water supply burner 1
The water introduced from the water supply pipe 4 and passing through the hot water supply heat exchanger 2 is turned into hot water by the combustion heat of the hot water supply burner 1, and the hot water passes through the bypass passage 10 at the outlet side of the hot water supply heat exchanger 2. The water is mixed with incoming water, and by this mixing, hot water at a set temperature, for example, 40 ° C., is produced and supplied to a desired hot water supply place via the hot water supply pipe 7. Then, when the faucet 9 is closed and the combustion of the hot water supply burner 1 is stopped, and the apparatus is in a standby state for the next hot water replenishment, the operation of the reheating function side starts, and the combustion fan When the fan 3 is rotated, the wind of the combustion fan 3 hits the hot water supply heat exchanger 2. The air introduced into the combustion fan 3 passes through the air supply pipe 22,
The exhaust gas 20 absorbs the heat of the exhaust gas generated by the combustion of the reburning burner 12, and further passes around the reburning heat exchanger 11 and the burner case 19 of the reburning burner 12. Because it is led to the inlet of 3,
The air introduced into the fan is sufficiently heated by absorbing the heat of the reheating function side, and the heated air passes through the hot water supply heat exchanger 2, so that the backup heating of the hot water supply heat exchanger 2 is performed. Done. Thereby, cooling of hot water in hot water supply heat exchanger 2 due to heat radiation of hot water supply heat exchanger 2 during hot water supply suspension is suppressed.

In this embodiment, for example, when the water in the bypass passage 10 and the hot water flowing out of the hot water supply heat exchanger 2 are mixed at a ratio of 2: 8, the temperature of the water entering through the water supply pipe 4 is set to 15 ° C.
Then, the temperature of the hot water in the hot water supply heat exchanger 2 is about 46.2 ° C. in order to make hot water having the set temperature of 40 ° C. flow out of the faucet 9. While the operation of the hot water supply heat exchanger 2 is stopped, the temperature of the hot water is reduced by cooling the hot water supply heat exchanger 2 within an allowable temperature range, for example, a set temperature of 40 ° C.
In order to keep the temperature within the range of −3 ° C., it is necessary to keep the hot water supply heat exchanger 2 at 42.5 ° C. or higher. For this purpose, the supply air temperature of the combustion fan 3 needs to be about 40 ° C. In the present embodiment, based on the above-described examination results, the air supply passage is controlled so that the temperature of the air introduced into the air supply port of the combustion fan 3 becomes approximately 40 ° C.
By setting a passage area of the passage 23 or providing a bumper (not shown) for opening and closing the passage area in the air supply passage 23 and controlling the opening / closing amount of the bumper, the supply air temperature of the combustion fan 3 can be reduced to 40. ℃.

According to the present embodiment, even when the reheating function side operates while the operation of the hot water supply heat exchanger 2 is stopped and the combustion fan 3 rotates, the cooling of the hot water supply heat exchanger 2 from the combustion fan 3 is performed. By supplying the suppressed warm air, cooling of the hot water in the hot water supply heat exchanger 2 is prevented. Thus, when the faucet 9 is opened and hot water is re-discharged, the hot water in the hot water supply heat exchanger 2 that has been kept warm is mixed with the water on the bypass passage 10 side, and the hot water within the allowable temperature range with respect to the set temperature. Since the hot water is discharged, and then the hot water of the set temperature is discharged by the combustion of the hot water supply burner 1, the fluctuation of the hot water temperature at the time of re-starting the hot water is very small, so that the user of the hot water does not feel uncomfortable. Hot water can be used comfortably.

FIG. 2 is an experimental result showing the effect of stabilizing the temperature of the re-filled hot water of this embodiment in comparison with the conventional example. In this experiment, re-watering was performed 5 minutes after stopping hot water supply under the conditions of room temperature 22 ° C., water temperature 17 ° C., set temperature 40 ° C., and hot water supply amount 12 liter / min. (B) shows the result of the conventional example, in which (a) shows the temperature of the hot water supply pipe immediately after the outlet of the hot water supply heat exchanger, and (b) of the same figure shows the hot water supply temperature after mixing. . Also, (c) and (d) of FIG.
Fig. 3C shows the result of the present embodiment, and Fig. 3C shows the temperature of the hot water supply pipe immediately after the outlet of the hot water supply heat exchanger 2, and Fig. 3D shows the hot water supply temperature after mixing.

As is apparent from the experimental results, in the present embodiment, the backup heating means 21 operates, so that the temperature drop of the hot water supply pipe after the stop of hot water supply is smaller than in the conventional example. Although the undershoot of the hot water temperature at the time of re-starting hot water is large, the undershoot disappears in the present embodiment, and it is possible to re-start hot water having a stable hot water temperature with small fluctuations in hot water temperature. Demonstrated by experiments.

FIG. 3 shows a second embodiment of the present invention. In this embodiment, a backup heating means 21 is formed by connecting the inside of an exhaust chamber 24 on the upper side of a reheating heat exchanger 11 and a combustion chamber on the lower side of a hot water supply heat exchanger 2 by a duct 25. . The exhaust chamber 24 is provided with a bumper 26 for selectively opening and closing the inlet side of the exhaust pipe 20 and the inlet side of the duct 25. When the hot water supply burner 1 is burning, the bumper 26 controls the inlet side of the duct 25. Closed, hot water supply burner 1
When the reburning burner 12 performs combustion while the combustion is stopped, the inlet of the exhaust stack 20 is closed (or the amount of closing is controlled) by the bumper 26 and the exhaust gas of the reburning burner 12 is passed through the duct 25. The exhaust gas guides the hot water supply heat exchanger 2 to the hot water supply heat exchanger 2 side, thereby backing up the hot water supply heat exchanger 2 to prevent heat radiation of the hot water supply heat exchanger 2 while the combustion of the hot water supply burner 1 is stopped. It suppresses the cooling of

By the heating with the exhaust gas, the hot water in the hot water supply heat exchanger 2 is kept warm. Then, when the faucet 9 is opened and the hot water is discharged again, the setting is performed in the same manner as in the first embodiment. Since hot water within an allowable range with respect to the temperature is supplied, it is possible to supply hot water having a stable hot water temperature with a small fluctuation in the hot water temperature.

FIG. 4 shows a third embodiment of the present invention. In this embodiment, an air supply port 28 is provided on the wall surface of the appliance case 27 on the reheating function side, and air taken in from the hot water supply port 28 when the combustion fan 3 rotates is discharged on the reheating function side, The backup heating means 21 is configured so as to reach the suction port of the combustion fan 3 while absorbing the heat of the burner 11 and the burner case 19 of the reheating burner 12. Also in this embodiment, when the reheating function side operates during the stoppage of the combustion of the hot water supply burner 1, the heat generated by the combustion of the reheating burner 12 on the reheating function side is absorbed to burn the air introduced from the air supply port 28. Since the hot water supply heat exchanger 2 is guided to the fan 3, the hot water supply heat exchanger 2 is back-up-heated by the warm wind sent from the combustion fan 3, and the cooling of the hot water in the hot water supply heat exchanger 2 while the combustion of the hot water supply burner 1 is stopped is suppressed.
As in the above-described embodiments, hot water having a stable hot water temperature with small fluctuations in the hot water temperature can be discharged again.

FIG. 5 shows a fourth embodiment of the present invention. In this embodiment, a heat conduction plate 30 for transmitting the heat of the exhaust gas from the exhaust pipe 20 to the hot water supply heat exchanger 2 is provided as a backup heating means 21 between the exhaust pipe 20 on the reheating function side and the hot water supply heat exchanger 2. It was done. Also in this embodiment, when the reheating unit operates during the stoppage of the combustion of the hot water supply burner 1, the heat of the reheating function side is added to the hot water supply heat exchanger 2 to heat it, and the combustion fan 3
The heat generated by the hot water supply heat exchanger 2 receiving the wind caused by the rotation can be compensated for, and the temperature of the hot water can be prevented from fluctuating when the hot water is again supplied, as in the above-described embodiments.

FIG. 6 shows a fifth embodiment of the present invention. In this embodiment, a reheater heat exchanger 11 and a hot water supply heat exchanger 2 are connected to a heat conductive plate 31 as a backup heating means 21.
Are connected using. In this embodiment as well, the reheating function side operates while the combustion of the hot water supply burner 1 is stopped, and even if the combustion fan 3 rotates, the heat for supplementing the heat radiation of the hot water supply heat exchanger 2 due to the wind of the combustion fan 3 makes the reheating burner 12. Is added to the hot water supply heat exchanger 2 from the reheating heat exchanger 11 side, so that cooling of the hot water in the hot water supply heat exchanger 2 is suppressed,
In the same manner as in the above-described embodiments, fluctuations in the temperature of the hot water can be suppressed, and hot water having a stable hot water temperature without undershoot can be discharged.

It should be noted that the present invention is not limited to the above embodiments, but can take various embodiments. For example, in each of the embodiments described above, the case of the reheating function is described as an example of another function, but the present invention is also applied to a combined water heater in which a hot water supply function and a gas heating function are arranged side by side.

Further, in each of the above embodiments, the combined water heater using gas as fuel has been described. However, a combined water heater using oil as fuel may be used.

Further, in each of the above embodiments, the bypass passage 10
And the mixing of hot water on the hot water supply heat exchanger 2 side and water on the bypass passage 10 side has been described as an example. However, a composite hot water supply apparatus having a mixing device of another configuration may be used. Also,
A connection pipe connecting the hot water supply pipe 7 and the circulation pipe 18 may be provided, or another bypass passage connecting the water supply pipe 4 and the circulation pipe 18 may be provided.

Further, the bypass passage 10 in each of the above embodiments is omitted, and the hot water produced by the hot water supply heat exchanger 2 is directly supplied to the hot water supply pipe 7.
It is good also as a structure which discharges hot water from faucet 9 through.

[0030]

According to the present invention, backup heating means is provided which absorbs heat accompanying the combustion of the other function burner and adds the absorbed heat to the hot water supply heat exchanger during operation stop. Since the heat generated by the rotation of the combustion fan during combustion of the burner and the heat radiation of the hot water supply heat exchanger due to natural air cooling are supplemented by the backup heating means, it is possible to suppress the cooling of the hot water in the hot water supply heat exchanger. Further, undershoot of hot water temperature at the time of hot water re-supply can be suppressed, and hot water of stable hot water temperature can be re-heated.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view showing a first embodiment of the present invention.

FIG. 2 is a graph of an experimental result showing an effect of the present embodiment in comparison with a conventional example.

FIG. 3 is a configuration explanatory view showing a second embodiment of the present invention.

FIG. 4 is a configuration explanatory view showing a third embodiment of the present invention.

FIG. 5 is a configuration explanatory view showing a fourth embodiment of the present invention.

FIG. 6 is a configuration explanatory view showing a fifth embodiment of the present invention.

[Explanation of symbols]

 2 Hot water supply heat exchanger 3 Combustion fan 11 Follow-up heat exchanger 12 Follow-up burner 21 Backup heating means 23 Supply passage 25 Duct 28 Supply port 30, 31 Heat conduction plate

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F24H 1/10 F24H 1/10 302

Claims (2)

(57) [Claims] 1. A combined water heater comprising a hot water supply heat exchanger heated by a hot water supply burner and a combustion system of a burner of another function other than the hot water supply, absorbs heat accompanying the combustion of the other function burner and absorbs the heat. A combined water heater comprising backup heating means for applying the heat to the hot water supply heat exchanger during operation stop. 2. A method for stabilizing a reheated hot water temperature of a combined hot water supply system comprising a hot water supply heat exchanger heated by a hot water supply burner and a combustion system of a burner other than the hot water supply, wherein the operation of the hot water supply heat exchanger is stopped. When the other-function burner is being burned, the heat generated by the combustion of the other-function burner is absorbed, and the absorbed heat is added to the hot water supply heat exchanger. A method for stabilizing the temperature of re-filled hot water in a combined water heater that suppresses cooling of hot water.