JPH04356656A - Method and apparatus for boiling-up in hot water storing type hot water heater - Google Patents

Abstract

PURPOSE:To perform an optional setting of a boiling-up temperature and an amount of boiling-up hot water and realize them. CONSTITUTION:Water is taken from a top part of a hot water storing tank 10 and a circulation passage 20 is disposed at an upper part of the hot water storing tank 10 and opened downwardly through a nozzle 23. The circulation passage 20 is provided with a circulation pump 21 and a heating source 22. High temperature hot water from the nozzle 23 has a reached height (h) determined by a flow speed (v) and water in a high temperature region A above an interface region K is uniformly increased, so that if a circulating amount Q is controlled, the flow speed (v) and the reached depth (h) are controlled to enable an arbitrary boiled-up amount of hot water to be attained and the boiling-up temperature at that time can be controlled according to the boiling-up time.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for boiling a hot water storage type water heater, and an apparatus therefor, in which both the boiling temperature and the amount of boiling water can be arbitrarily set.

0002

[Prior Art] Hot water storage type water heaters, including electric water heaters, generally have a heater installed at the bottom of a closed hot water storage tank, and use natural convection to boil the water in the tank. There is no problem in boiling the entire amount of hot water, but it is difficult to boil a part of it to a high temperature, and therefore it is difficult to quickly add to the boiling water for a small amount of insufficient hot water.

[0003] Therefore, a water heater has been proposed in which the heating source is external and a forced circulation system is adopted (for example, Japanese Patent Publication No. 2-43984). In this system, the water intake side of a circulation path equipped with a circulation pump and a heating source is connected to the lower part of the hot water storage tank, and the other end is opened to branch into the top and middle part of the hot water storage tank. When boiling the entire amount of water in the hot water storage tank, the water is circulated to the middle part, and when boiling a small amount, it is circulated to the top part. In either case, the amount of water circulated through the circulation path (hereinafter simply referred to as the amount of circulation) is small; therefore, boiling involves replacing cold water in the hot water storage tank with hot water that is heated and circulated. Since there is no mixing of the two, the temperature distribution of the boiled water is uniform.

There is also a method in which the water intake side of the circulation path is placed in the upper part of the hot water storage tank, and the heated hot water is returned to the lower and intermediate portions of the hot water storage tank (Japanese Patent Laid-Open No. 58-28934). The heated high-temperature water is circulated to the lower part of the hot water storage tank when the entire amount is to be boiled, and is circulated to the middle part when a small amount is to be boiled. In either case, by keeping the circulation amount to a small amount and circulating high-temperature hot water, it is possible to achieve a good uniform water temperature.

[0005]

[Problem to be Solved by the Invention] The former method of the prior art is said to be uneconomical because it takes a long time to boil water because the remaining hot water cannot be used effectively when boiling a small amount. There was a problem. That is, this is a boiling method in which the cold water at the bottom of the hot water storage tank is newly heated to become hot water, which is returned to the top of the hot water storage tank to replace the remaining hot water.

[0006] Furthermore, in the case of the second prior art, since the amount of circulation is small, natural convection is basically used for boiling, and therefore, the amount of hot water to be boiled is determined by the position to which the high-temperature water is returned. In other words, the amount of hot water to be boiled is 2, which corresponds to the upper part from the middle of the hot water storage tank or the entire amount of the hot water storage tank.
The drawback is that it can only be set in stages.

Furthermore, in any of the conventional techniques, it is impossible to actively control the amount of boiling water when boiling a small amount from the outside. Furthermore, since the temperature distribution of the boiled water is determined by natural convection, it has been virtually impossible to set and realize arbitrary boiling temperatures and amounts of boiling water.

[0008] In view of the problems of the prior art, an object of the present invention is to heat water taken from the top of a hot water storage tank, circulate it as high-temperature hot water, and spray it downward at the top of the hot water storage tank. Both the boiling temperature and the amount of boiling water can be set arbitrarily by boiling only the part above the depth that the high-temperature water reaches (hereinafter referred to as the "reaching depth") while forcibly stirring. The present invention relates to a boiling method for a hot water storage type water heater that can efficiently and accurately realize the following, and a device thereof.

[0009]

[Means for Solving the Problems] The configuration of the first invention according to this application for achieving the above object is to take water from the top of the hot water storage tank when boiling a hot water storage type water heater equipped with a closed hot water storage tank. The gist of this system is to continuously control the amount of boiling water by circulating water through a heating source to the upper part of the hot water storage tank and ejecting it downward within the tank to control the amount of circulation.

[0010] The configuration of the second invention includes a closed type hot water storage tank, a circulation path that connects the water intake side to the top of the hot water storage tank and opens downward through a nozzle at the top of the hot water storage tank.
The gist thereof is to include a circulation pump and a heating source interposed in the circulation path.

[0011] The nozzles may be provided in a plurality of stages in the vertical direction of the hot water storage tank, and the heat source may be provided with a heat amount controller.

0012

[Operation] According to the configuration of the first invention, the water taken from the top of the hot water storage tank is circulated to the top of the hot water storage tank via the heating source, becomes high temperature hot water, and is spouted downward. It is forcibly mixed with the cold water in the tank,
mixed. At this time, the depth that the hot water reaches, that is, the depth that the hot water reaches, is determined by the flow velocity at which the hot water jets out, and therefore, the depth that the hot water reaches can be controlled by controlling the amount of circulation.

Generally, when hot water is spouted into cold water in this way, the temperature of the area above the reaching depth increases almost uniformly due to the mixing of the hot water and cold water, and the high temperature area is On the other hand, the area below the reaching depth remains a cold body of water and hardly rises in temperature. That is, a clear boundary area can be formed between the two. Therefore, by controlling the circulation rate and the depth to which high-temperature water reaches, it is possible to actively control the amount of boiling water steplessly from the outside, and the boiling temperature at this time can be controlled steplessly. , can be controlled by heating time. Note that the temperature distribution within the high temperature region can generally be made extremely uniform because forced mixing is performed by jet flow.

[0014] Furthermore, the high-temperature hot water circulated at this time should not cause boiling or bumping, and therefore the heating source may be operated at the maximum heat amount within this range.

According to the configuration of the second invention, the circulation pump heats the water taken in at the top of the hot water storage tank by the heating source and jets it downward through the nozzle at the top of the hot water storage tank. By controlling the flow rate and the circulation amount, the first invention can be carried out as is.

[0016] If the nozzles are arranged in multiple stages in the vertical direction, even if the height of the hot water storage tank is large, by using the nozzles on the lower stage, the reaching depth can be easily reached at the bottom of the hot water storage tank. Therefore, even in a large-capacity hot water storage tank, a high temperature region can be formed throughout the tank.

[0017] If a heat amount controller is attached to the heating source,
The heating source can be automatically operated at the maximum amount of heat within a range that does not cause the circulating water to boil or cause bumping.

[0018]

[Embodiment] Hereinafter, an embodiment will be explained with reference to the drawings.

[0019] The hot water storage type water heater has a closed type hot water storage tank 10.
and a circulation path 20 attached to the hot water storage tank 10 (FIG. 1).

[0020] The hot water storage tank 10 is a hermetically sealed tank that has been subjected to heat insulation treatment on the outside, and has a water supply pipe 11 connected to its bottom and a hot water supply pipe 12 connected to its top. Also,
A plurality of temperature sensors 13a, 13b... are attached to the pipe wall of the hot water storage tank 10 in the vertical direction.

The water intake side of the circulation path 20 is connected to the top of the hot water storage tank 10. However, the water intake side of the circulation path 20 may be branched from the hot water supply pipe 12, although not shown in the drawings.

A circulation pump 21 and a heating source 22 are interposed in the circulation path 20, and the other end of the circulation path 20 is introduced into the upper part of the hot water storage tank 10, and the hot water is heated through a nozzle 23. It opens downward inside the tank 10. A temperature sensor 24 a is attached to the exit side of the heat source 22 , and the output of the temperature sensor 24 a is guided to the heat controller 24 , while the output of the heat controller 24 is connected to the heat source 22 .

The heating source 22 can heat the circulating water flowing through the circulation path 20 by using any heat source such as electricity, gas, kerosene, heat pump, solar, etc.
At this time, the calorie controller 24 controls the temperature sensor 24a.
The amount of heat of the heating source 22 is controlled to the maximum within a range where boiling or bumping does not occur in the heating source 22 by the output.

Now, the hot water storage tank 10 is connected via the water supply pipe 11.
After filling the hot water storage tank 10 with cold water, the water in the hot water storage tank 10 can be boiled by activating the heating source 22 and operating the circulation pump 21. At this time, the flow rate of the circulation pump 21, that is,
Depending on the magnitude of the circulation amount Q in the circulation path 20, the temperature rise curve in the hot water storage tank 10 becomes approximately as shown in FIG. 2.

When the circulation amount Q is small ((A) in the same figure),
The temperature T corresponding to the temperature sensor 13a at the upper part of the hot water storage tank 10 increases as time t passes, and the temperature T corresponds to the time t=t1.
As the time progresses, T=To and boiling can be completed (curve a in the figure). At this time, the temperatures T corresponding to the temperature sensors 13b and 13c at the middle and lower portions of the hot water storage tank 10 remain almost unchanged (curves b and c in the figure).

[0026] When the circulation amount Q is slightly increased ((B) in the same figure)
), the temperature T corresponding to the intermediate temperature sensor 13b also rises with the passage of time t, and when t=t2 >t1, T=T1≦To, and boiling can be completed. At this time, the difference ΔT1 between the final temperatures To and T1 corresponding to the temperature sensors 13a and 13b = To −
T1 is extremely small. When the circulation amount Q is further increased ((C) in the same figure), the temperature T corresponding to the lower temperature sensor 13c also rises, and when t=t3 >t2, T=T.
2≦T1, and boiling is completed. In addition, the difference ΔT2 between the final temperature To and T2 at this time = To−T2
is also very small.

When the heating source 22 is activated and the circulation pump 21 is operated, the hot water heated by the heating source 22 is jetted downward from the nozzle 23. At this time, the flow rate v of the hot water from the nozzle 23 is , determined by the amount of circulation Q. On the other hand, the high-temperature hot water spouted from the nozzle 23 in this way is forcibly mixed with the cold water in the hot water storage tank 10, but at this time, the depth h that the jet from the nozzle 23 can reach is determined by the flow rate. It is a function of v. This is because the jet stream from the nozzle 23 is at a high temperature and is therefore subject to buoyancy from the cold water.

Therefore, the water in the hot water storage tank 10 has a boundary area K which is located below the nozzle 23 at a distance h, and above which the high temperature hot water and cold water from the nozzle 23 are forced. It is possible to form a high-temperature region A whose temperature increases with the passage of time t, and to form a cold region B below the boundary region K which is not affected by the high-temperature hot water from the nozzle 23. Therefore, only the amount of boiling water corresponding to the high temperature area A above the boundary area K can be boiled.

[0029] Generally, the water in the high temperature range A is forcibly mixed with the high temperature hot water from the nozzle 23 and the cold water in the hot water storage tank 10, so the temperature distribution inside the water changes during the temperature rise. It has been found that the results are extremely uniform, including (Figure 3). However, in the figure, the total height H of the hot water storage tank 10 =
The figure shows the change in temperature T at each point in the HTK over time t, and the figure also shows the height H of the nozzle 23.
In addition to =HN, the downward reaching depth h of the nozzle 23 is also shown. Note that here, the boundary region K has a thickness h
It is formed in layers with k.

In this way, by controlling the circulation amount Q of the water in the hot water storage tank 10, the reaching depth h is controlled, and the amount of boiling water corresponding to the high temperature range A at that time is nullified. It can be realized in stages. Moreover, the boiling temperature can also be arbitrarily achieved by appropriately determining the length of time t.

[0031] The heating source 22 during the boiling operation can be operated at the maximum amount of heat within a range that does not cause boiling or bumping, so that the required boiling time can be minimized, but the boiling time may be longer. If possible, reduce the heat level,
Alternatively, it goes without saying that the heating capacity may be reduced. Further, if the heating capacity of the heat source 22 is small and there is no risk of boiling or the like occurring within the circulation path 20, the heat quantity controller 24 can be omitted.

[0032]

[Other Embodiments] The heat source 22 can be formed by a heater 22a and a cover 22b covering the heater 22a (FIG. 4). The heater 22a is inserted into the hot water storage tank 10 at the upper part of the hot water storage tank 10, and the circulation path 20 is opened into the cover 22. Further, the nozzle 23 is
It is formed in a part of the cover 22b. Since the heating source 22 is not externally attached but is housed within the hot water storage tank 10, the whole can be made more compact.

The nozzles 23 can be provided in multiple stages in the vertical direction of the hot water storage tank 10 (FIG. 5). Each nozzle 23
On the outlet side of the heat source 22, the switching valves 23a, 23
It is branched through a...

[0034] The amount of boiling water is small, and the nozzle 23 on the top stage
When the amount of boiling water can be achieved by reaching depth h,
Only the top nozzle 23 needs to be operated, and for a larger amount of boiling water, the lower nozzle 2
3, 23 should be activated. In addition, at this time, the nozzles 23, 23, . It is preferable to complete boiling in the high temperature range A, and then add the insufficient amount of boiling water to the nozzles 23 in the second stage and below. However, even with nozzles 23 other than the top row,
When a sufficiently uniform temperature distribution is obtained, the nozzles 23 in the second and lower stages from the beginning of boiling are operated, thereby forming a high temperature region A corresponding to a predetermined amount of boiling water.

The nozzles 23, 23 on the lower stage have a reaching depth h
Since the hot water can be expanded downward to reach the bottom of the hot water storage tank 10, even if the total height HTK of the hot water storage tank 10 is large, it is possible to easily boil the entire amount. However, regardless of illustration, the nozzles 23, 23, .

[0036] Generally, if the diameter of the hot water storage tank 10 is several tens of centimeters, the nozzle 23 is installed at the center of the tank.
It is sufficient to arrange one piece, but if the diameter is larger, a plurality of pieces may be arranged at the same height position as necessary. It is possible to improve forced mixing of hot water and cold water, and to equalize the temperature of boiling water.

[0037]

[Effects of the Invention] As explained above, according to the first invention of this application, water taken from the top of the hot water storage tank is
By circulating the hot water to the upper part of the hot water storage tank via a heating source and ejecting it downward in the hot water storage tank, the ejected high-temperature hot water becomes cold water in the high-temperature region above the reaching depth determined by the flow rate, that is, the circulation amount. The amount of boiling water corresponding to the high temperature range can be boiled, and the boiling temperature at that time is determined by the boiling time, and the temperature distribution within the high temperature range is uniform, so the boiling temperature This has an excellent effect in that both the amount of boiling water and the amount of boiling water can be set arbitrarily, and this can be achieved efficiently and reliably.

According to the second invention, the hot water storage tank is provided with a circulation pump and a circulation path equipped with a heating source, and the circulation path connects the water intake side to the top of the hot water storage tank, and connects the circulation path downward through a nozzle at the top of the hot water storage tank. By opening the nozzle, heated high-temperature water is ejected from the nozzle, and by controlling the circulation amount, an arbitrary amount of boiling water can be set, so the first invention can be carried out smoothly. .

[Brief explanation of the drawing]

[Figure 1] Overall configuration explanatory diagram

[Figure 2] Operation explanation diagram (1)

[Figure 3] Operation explanation diagram (2)

[Figure 4] A diagram equivalent to Figure 1 showing another embodiment

[Figure 5]
A diagram corresponding to FIG. 1 showing another embodiment

[Explanation of symbols]

Q... Circulation amount 10...Hot water storage tank 20...Circulation path 21...Circulation pump 22...Heating source 23...Nozzle 24...Calorie controller

Claims (4)

[Claims] Claim 1: When heating a hot water storage type water heater equipped with a closed hot water storage tank, water taken from the top of the hot water storage tank is circulated to the top of the hot water storage tank via a heating source, and the water is circulated downward within the hot water storage tank. A boiling method for a hot water storage type water heater, characterized by steplessly controlling the amount of boiling water by ejecting hot water and controlling the circulation amount. 2. A closed type hot water storage tank, a circulation path having a water intake side connected to the top of the hot water storage tank and opening downward through a nozzle at the top of the hot water storage tank, and a circulation interposed in the circulation path. A hot water storage type water heater comprising a pump and a heating source. 3. The hot water storage type water heater according to claim 2, wherein the nozzles are provided in multiple stages in the vertical direction of the hot water storage tank. 4. The hot water storage type water heater according to claim 2, wherein the heat source includes a heat quantity controller.