JPH02133753A - Electric hot water device - Google Patents

Abstract

PURPOSE:To prevent the time necessary for boiling from unfairly being long and an additionally burning function from being insufficient by incorporating a calculating function of a proper circulation flow and a flow control function on the basis thereof in a control device. CONSTITUTION:At first, a hot water quantity V and a set hot water temperature T set in a hot water quantity and temperature set means 24 are taken in and an additionally burning set means 25 judges whether or not an additionally burning mode is instructed, and when the additionally burning mode is not instructed, a start time t1 for supplying electricity to a heater 11 is determined so that the quantity corresponding to a hot water quantity V of water W in a hot water storage tank 10 is boiled up to a hot water temperature T in a specified time and after the time t1 elapsed the heater 11 is supplied with electricity. After upper temperature Tb is higher than hot water temperature T and the circulation flow F of a circulating pump 14 is calculated, the pump 14 is started and the boiling of the hot water quantity V is completed as the flow F is modified properly. When the additionally burning mode is instructed, immediately the heater 11 is turned on electricity and additional burning of the hot water quantity V is performed without waiting determination of the time t1 and elapse thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application of Industry-1- This invention relates to a so-called push-up type electric water heater that uses a closed hot water storage tank that supplies water from below and hot water from the top.

Conventional technology Push-type electric water heaters always operate with the hot water storage tank filled with water, so when hot water is used, cold water is replenished according to the amount used. Therefore, if the entire amount of hot water stored in the hot water storage tank is used, cold water will be supplied from the hot water faucet, causing unexpected inconvenience.

When the amount of hot water is insufficient, the heater in the hot water tank must be reheated to reheat the water, but in conventional electric water heaters, the heater is inserted at the bottom of the hot water tank. Therefore, even in this case of reheating, it was necessary to heat the entire amount of water in the hot water storage tank, and therefore, the time required for reheating was too long, so reheating was practically impossible.

Therefore, a heater is inserted into part of the hot water storage tank, and a circulation pump is installed to forcibly circulate the water in the hot water storage tank, thereby heating at least the water in the upper part of the hot water storage tank in a short period of time. There is a known device that realizes the reheating function in such a way as to be able to do so (Japanese Utility Model Publication No. 19164/1983). The circulation pump in this device starts when the water in the lower part of the hot water storage tank is heated to a predetermined temperature and circulates the water, while the cold water in the lower part is pumped upward.
It pauses when the temperature at the top drops, and by repeating this process, it finally works to bring the entire amount of water in the hot water storage tank to a boil.

Problems to be Solved by the Invention The conventional technology does not have any means for controlling the circulation flow rate of the circulation pump, so problems in the boiling operation occur due to excess or deficiency of the circulation flow rate. The fear is unavoidable. In other words, when the circulation flow rate is insufficient, the water temperature at the top of the hot water storage tank becomes too high, causing intermittent power supply to the heater.
On the one hand, the time required for boiling becomes longer, and on the other hand, if the circulating flow rate is too high, the temperature of the water at the top of the hot water storage tank may not be sufficient.
L does not rise, making it impossible to achieve the reheating function of supplying hot water at a predetermined temperature within a short period of time.

Therefore, in view of the actual state of the prior art, the purpose of the present invention is to incorporate a function for calculating an appropriate lower circulation flow rate and a flow rate control function based on this into a control device, thereby making it possible to take an unreasonable amount of time required for boiling. To provide a new electric water heater that is free from the risk of being too long or having insufficient reheating function.

Means for Solving the Problems The structure of the present invention to achieve the object is to insert a heater at a predetermined height position in the middle of the hot water storage tank, connect the suction side to the lower part of the hot water storage tank, and connect the heater to the bottom of the hot water storage tank. A circulation pump is installed whose discharge side is connected to a water pipe that runs up the inside of the hot water storage tank and opens at the top of the hot water storage tank.Furthermore, the appropriate circulation flow rate of the circulation pump is determined based on the set hot water temperature and the upper and lower temperatures of the hot water storage tank. The gist is to combine the circulation pump with a control device that controls the flow rate in accordance with calculation 1~.

Note that the control device may include a reheating setting means for specifying the reheating mode, and the circulation pump may
It is also possible to prevent it from operating in reheating mode.

With this configuration, the circulation flow rate of the circulation pump can be controlled so that the hot water temperature in the upper part of the hot water storage tank is always maintained at the set water temperature, and therefore Hot water that has been boiled to the set temperature can be stored from the L side of the hot water storage tank, so hot water at a predetermined temperature can be stored.
Depending on the amount used, any predetermined amount can be quickly boiled.

Moreover, since the hot water thus heated is stored in the upper part of the hot water storage tank, hot water at a predetermined temperature can be used within a short time even in the reheating mode.

In addition, when in reheating mode, the operation of the circulation pump is controlled by the body weight or
Then, since the water in the hot water storage tank is only circulated naturally by the heater, the area where it can be effectively heated is limited to the area above the heater. By selecting a predetermined position where the amount of water required for reheating can be obtained, there is no risk of inadvertently reheating more hot water than the required amount.

In addition, since the water pipe on the discharge side of the circulation pump runs inside the hot water storage tank, heat radiation loss from the water pipe can be extremely reduced.

It works as follows.

Example Examples will be described below with reference to the drawings.

The electric water heater is a combination of a hot water storage tank 10 containing a heater 11 and a control device 20 (FIG. 1).

The hot water storage tank 10 is a sealed pressure tank, and has a heat insulating layer 10a on its outer periphery, and a water supply pipe 1 connected to a water supply source such as a water pipe at the bottom via a water supply valve 1-Ob. -Oc is provided, and at the top there is a hot water faucet, K...
・Hot water pipe connected to 1. Od is provided. The hot water storage tank 10 is always filled with water W, and the hot water tap KSK.
When opening the water supply pipe 10c to supply hot water, the same amount of cold water as the amount of hot water used is automatically replenished from the water supply pipe 10c.

A heater 11 is inserted into the side wall of the hot water storage tank 10 at a predetermined height position in the middle part in the vertical direction, and Enoki's temperature detectors 1-2. 12・
... are installed at equal intervals. Temperature detector 12.1-2
... Any type of thermistor, thermocouple, etc. can be used for closing, and each can detect the temperature of the water W at the mounting height position.

A circulation pump 14 is attached to the hot water storage tank 10. The suction side of the circulation pump 14 is connected to the lower part of the hot water storage tank 10, and the discharge side thereof penetrates the circumferential wall of the hot water storage tank 10, enters the inside thereof, extends upward inside the hot water storage tank 10, and connects to the upper part of the hot water storage tank 10. Water pipe 14a that opens at
It is connected to the. The circulation pump 14 is connected to the hot water storage tank 10
In order to effectively circulate the water W that is boiled inside, use one that has sufficient heat resistance.

The control device 20 includes a calculation means 21 and a heater control means 22.
and a flow rate control means 23.

Calculating means 2]- is connected to the outputs of temperature detectors 12, 12, etc., as well as the amount of hot water for setting the amount of hot water V to be boiled in the hot water storage tank 10 and the set water temperature T thereof. A hot water temperature setting means 24 and a reheating setting means 25 for specifying a reheating mode are connected. In addition, calculation means 2
] is the control command signal 21. a, 21b, the heater control means 22 and the flow rate control means 23 are manually operated.

The heater control means 22 and the flow rate control means 23 are interposed between the power supply AC and the heater 1]-1 circulation pump 14, respectively. However, 1. The heater control means 22 is a switching element that controls the supply of power to the heater 11 according to the control command signal 21a from the calculation means 21,
A contactor or thyrisk switching element, etc. shall be used.

Further, the flow rate control means 23 is a flow rate controller that sets and controls the rotation speed of the circulation pump 14, for example, in accordance with a control command signal 21b that specifies the circulation flow rate vp of the circulation pump 14.

The operation of the electric water heater having such a configuration can be defined by a software program constituting the calculation means 21 (FIG. 2).

First, the program reads the hot water amount and the set hot water temperature set in the hot water amount and temperature setting means 24 (program step (1) in Fig. 2, hereinafter simply referred to as (1)). .

Next, it is determined whether the reheating mode is specified by the reheating setting means 25 (2), and if it is not the reheating mode, the set hot water itV is used from the water W in the hot water storage tank 10. The heater 11 is set so that the corresponding amount of water is boiled to the set temperature of 1" within a predetermined time period.
Determine the energization start time t1 (3), wait for the energization start time t1 to pass (4), and energize the heater 11 (5).
).

Here, in program step (3), the energization start time t1 can be determined, for example, by the following procedure: temperature sensor of the hot water storage tank 10]2.
From each output of 12..., the temperature distribution of the water W in the hot water storage tank]O is detected, and based on this, the amount of heat Qo held in the hot water storage tank 10 is calculated. Next, set the amount of hot water ■ and the set water temperature 1
From ゛, we can calculate the thermoelectricity Q required to obtain this amount of hot water ■, so we can calculate the boiling time ′I″f required for the heater 11 to supply the heat/quantity difference ΔQ-Q-QO. , the energization start time tl = t by going back by the boiling time Tf from the predetermined scheduled boiling completion time t2.
2-'T''f may be determined.

Note that when late-night power is used as a power source for the heater 11, the scheduled boiling completion time t2 is generally set to coincide with the end time of the late-night power supply period. However, the power supply start time is adjusted so that the boiling time Tf coincides with the time period when the power load is the lowest among the power supply time periods for late-night power, for example, around 3:30 a.m. t1 can also be determined, making it possible to further contribute to leveling the load on the power system.

After energizing the heater 11 (5), wait until the upper temperature Tb of the hot water storage tank 10 becomes higher than the set hot water temperature T (6), and after calculating and determining the circulation flow fiF of the circulation pump 14 (7),
Start the circulation pump 14 (8). Here, the circulation flow rate F
For example, it is calculated by F=aH/(T-Ta), where a is a proportionality constant considering heating efficiency, H is the capacity of the heater]1-, and Ta is the temperature at the bottom of the hot water tank. It is. Since the flow rate of the circulation pump] 4 is controlled by the control means 23 so as to realize the circulation flow rate F determined in this way, two portions of the hot water storage tank 10 are provided with a set water temperature T. You can boil and accumulate nearly identical amounts of hot water.

Heater]-1 is energized 5), circulation pump 14 is started (8), and circulation flow rate ■? While modifying (10
), waits for the completion of boiling the amount of water V (9), stops the heater 11 and circulation pump 14 (1, 1), and completes the boiling operation. Here, the correction of the circulating flow ff1F is performed in the hot water storage tank 1
Depending on whether or not the lower temperature 'Fb of 0 is greater than the set hot water temperature 1', for example, Fo = F + ΔF1 ΔF = b'T"b
/T (where ΔF is the amount of correction of the circulating flow rate, and b is a positive proportionality constant), the appropriate circulating flow it F o can be calculated. By performing such a correction operation for the circulation flow rate F, variations in the capacity of the heater 11, voltage fluctuations in the power supply AC, changes in the lower temperature 'Fa due to the mixing of water and hot water in the hot water storage tank]O, etc. can be avoided. Also, hot water tank 10
It is always possible to store hot water at the preset temperature T from one side. The completion of boiling in program step (9) is detected by temperature detectors 12, 12, . . . arranged in the vertical direction of the hot water tank 10.
This can be done easily and accurately when the water temperature detected by the one at a predetermined height reaches the set water temperature of 1.

The hot water thus heated to the -C5 set water temperature can be freely used in the hot water faucet via K....

When the reheating mode is designated by the reheating setting means 25 (2), the energization start time t1 is determined and the process is not waited for (immediately energize the heater 15). Thereafter, similar control is used to reheat the amount of hot water V. In this case, as in the case described above, hot water at the set temperature T is stored from the upper part of the hot water storage tank 10, so hot water can be used in an extremely short period of time, which is effective in situations where the amount of hot water is insufficient. can be dealt with. It should be noted that the heater 11 can be energized at any time in the reheating mode using power from the power source AC even if the main boiling operation described above is performed using late-night power.

In addition, in the reheating mode, the circulation pump 14 can be stopped and boiling can be performed only by energizing the heater 11. At this time, only the water W in the hot water storage tank 1-0 corresponding to the upper part of the heater 11 can be boiled by natural circulation, and the amount of water to be boiled at that time is:
Since the heater is limited to the upper part of the heater]1-, there is no need to boil up a large amount of water W unnecessarily even in the case of incorrect setting of the water amount (2).

As described in detail, according to the present invention, a heater is inserted at a predetermined height position in the middle of a hot water storage tank, a circulation pump is provided, and the circulation flow rate of the circulation pump is appropriately controlled. , from the -L side of the hot water tank,
The hot water that has been boiled to the set temperature can be stored and sent to B. Therefore, it is possible to always boil a predetermined amount of hot water at a predetermined temperature, and it can be used accurately even in reheating mode. It has the excellent effect of being able to respond to

In addition, the water pipe connected to the discharge side of the circulation pump passes through the inside of the hot water storage tank and is opened at the - side of the hot water storage tank, so heat radiation loss from the water pipe can be minimized and energy can be reduced. It also has the excellent effect of improving efficiency.

[Brief explanation of the drawing]

Figures 1 and 2 show examples; Figure 1 is an overall system diagram;
FIG. 2 is a program flowchart. Fo... Proper circulation flow 'F... Set hot water temperature 1゛ b... 1 Partial temperature Ta... Bottom temperature] 0... Hot water storage tank 11... Heater 12... Temperature detector 14...Circulation pump 1-4a...Water pipe 20.
...Control device 25...Additional heating setting means

Claims (1)

[Scope of Claims] 1) A closed type hot water storage tank that supplies water from the bottom and from the top, a heater inserted at a predetermined height position in the middle of the hot water storage tank, and a suction side located at the bottom of the hot water storage tank. connect to
The discharge side consists of a circulation pump connected to a water pipe that runs up the inside of the hot water storage tank and opens at the top of the hot water storage tank, and a control device, and the control device controls the set hot water temperature and the upper temperature of the hot water storage tank. An electric water heater characterized in that an appropriate circulation flow rate is calculated from the and lower part temperature, and the flow rate of the circulation pump is controlled. 2) The electric water heater according to claim 1, wherein the control device includes a reheating setting means for specifying a reheating mode. 3) The electric water heater according to claim 2, wherein the circulation pump does not operate in the reheating mode.