JPH0776636B2 - Hot water temperature control method for heat storage type electric water heater - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot water supply temperature control method for a heat storage type electric hot water supply device.

[0002]

2. Description of the Related Art Some electric water heaters use a solid regenerator as a heat source. Further, in this heat storage type electric water heater, a heating element, a solid heat storage element which is heated by the heating element and accumulates heat, and air is sent to the solid heat storage element to heat the solid heat storage element by the heat released from the solid heat storage element. A fan, a heat exchanger for exchanging heat between air and water heated by the heat released from the solid heat storage body, and a hot water storage tank for storing hot water obtained by heating the water by the heat exchanger. Some have a first pump that circulates water between the heat exchanger and the hot water storage tank, and a water tap that discharges hot water stored in the hot water storage tank.

In this heat storage type electric hot water supply device, in the heat exchanger, heat is exchanged between the air heated by the solid heat storage body sent by the fan and the water circulated by the pump, so that the water has a predetermined temperature. The heated hot water having a predetermined temperature is stored in the hot water storage tank and supplied from the water tap. That is, hot water having the temperature obtained by the heat exchanger is supplied from the water tap.

Conventionally, in order to obtain a predetermined hot water temperature in this heat storage type hot water supply device, the idea is that if the air volume of the air sent by the fan is large, the heat quantity increases and the hot water temperature can be raised. Based on the above, regardless of the temperature of the solid heat storage body, the flow rate of water by the pump is made constant, and the fan is rotated at the number of rotations corresponding to the temperature of the hot water to obtain the predetermined hot water temperature.

[0005]

However, the hot water temperature control method as described above has the following problems. That is, in practice, when the temperature of the solid heat storage body is higher than a certain height (for example, 250 ° C.) and the output is sufficiently large, the rotation speed of the fan is increased to increase the air volume of the air sent by the fan. However, when the temperature of the solid heat storage body is lower than a certain height (for example, 250 ° C.) and the output is low, the air flow rate of the air increases due to the increase in the rotation speed of the fan. The amount of heat on the solid regenerator side does not increase in proportion to the increase, and as a result, the hot water temperature cannot rise in proportion to the increase in the rotation speed of the fan.

On the other hand, conventionally, as described above, even when the temperature of the solid heat storage body is lower than a certain height (for example, 250 ° C.) and the output is low, the fan is rotated while the water is circulated by the pump, and the predetermined power is supplied. Attempting to obtain hot water temperature. That is, the temperature of the solid heat storage body is at a certain height (for example, 250
When the output is lower than (° C), the fan is rotated while circulating water with the pump. Therefore, the temperature stratification is not formed in the hot water stored in the hot water storage tank, and the predetermined hot water temperature cannot be quickly obtained.

As described above, conventionally, when the temperature of the solid heat storage body is lower than a certain height (for example, 250 ° C.) and the output is low, the solid heat storage is proportional to the increase in the air volume of the air due to the increase in the rotation speed of the fan. The operation control of the fan and the pump is not performed according to the situation that the amount of heat on the body side does not increase and, as a result, the hot water temperature cannot be increased in proportion to the increase in the rotation speed of the fan. In this case, the heat released from the solid heat storage body is effectively consumed and wasted. Further, the fan and the pump are not effectively operated in order to obtain a predetermined hot water temperature, and are wasted, which is very uneconomical.

The present invention has been made based on the above circumstances, and when the temperature of the solid heat storage body is lower than a certain height and the output is low, the operation control of the fan and the pump according to this situation is performed, and the solid heat storage body is controlled. (EN) It is possible to provide a hot water temperature control method for a heat storage type electric hot water supply device, which can effectively use the heat stored in the hot water to obtain a necessary hot water temperature and can economically operate a fan and a pump. To aim.

[0009]

In order to achieve the above object, a hot water supply temperature control method for a heat storage type electric hot water supply device according to the present invention comprises:
A heating element, a solid heat storage element that is heated by the heating element to accumulate heat, a fan that sends air to the solid heat storage element and heats it by the heat released from the solid heat storage element, and a solid heat storage element that releases the heat. Heat exchanger for exchanging heat between the air and water heated by the heat, a hot water storage tank for storing hot water obtained by heating water in the heat exchanger, the heat exchanger and the hot water storage In a heat storage type electric water heater comprising a pump that circulates water between the tank and a water tap that outputs hot water stored in the hot water storage tank, when the temperature of the solid heat storage body is higher than a certain height, The fan and the pump are rotated according to the temperature at which the hot water stored in the hot water storage tank is to be obtained, and when the temperature of the solid heat storage body falls below a certain height, the fan and the Stop pump rotation After that, when the temperature of the solid heat storage body is lower than a certain height and water is supplied to the hot water storage tank, the rotation of the fan and the pump is continuously stopped, and the temperature of the solid heat storage body is high. When it is less than the above and water is not supplied to the hot water storage tank,
The pump is rotated at a rotation speed within a range in which water is circulated at a speed that does not stir the hot water stored in the hot water storage tank, and the fan is responsive to the temperature at which the hot water stored in the hot water storage tank is to be obtained. It is characterized by rotating at the number of rotations.

[0010]

When the temperature of the solid heat storage body is lower than a certain level, the rotation of the fan and the pump is stopped to form a temperature stratification on the hot water stored in the hot water storage tank. Here, the temperature stratification refers to an orderly temperature distribution in which the temperature of hot water in the hot water storage tank rises from the lower part to the upper part of the tank. In general, water is supplied to the bottom of the hot water storage tank to raise the temperature of the water below this temperature stratification.

Thereafter, when water is supplied to the hot water storage tank when the temperature of the solid heat storage body is lower than a certain level, the hot water stored in the hot water storage tank is agitated by continuously stopping the rotation of the fan and the pump. Without breaking the temperature stratification of hot water.

After that, when the temperature of the solid heat storage body is lower than a certain height and water is not supplied to the hot water storage tank, rotation of water is circulated at a speed that does not agitate the hot water stored in the hot water storage tank. The hot water stored in the hot water storage tank is stirred and the temperature stratification is destroyed by rotating the pump at a speed and rotating the fan at the number of rotations corresponding to the temperature at which the hot water stored in the hot water storage tank is to be obtained. Without that, the temperature of the water below the temperature stratification can be raised.

In this way, when the temperature of the solid regenerator is lower than a certain height and the output is low, the amount of heat on the side of the solid regenerator does not increase in proportion to the increase in the air volume due to the increase in the rotation speed of the fan. As a result, appropriate operation control of the fan and the pump is performed according to the situation that the hot water temperature cannot be raised in proportion to the increase in the rotation speed of the fan. As a result, the heat released from the solid heat storage body is effectively consumed to obtain a predetermined hot water temperature, and the fans and pumps are effectively operated to obtain the predetermined hot water temperature, which is economical without waste. You can drive.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. The heat storage type electric hot water supply apparatus to which the present invention is applied will be described. In FIG. 1, 1 is a case, 2 is a heating element, 3
Is a solid heat storage body which is provided inside the case 1 and is heated by the heat generating body 2 to accumulate heat, and 4 is a fan which sends air to the solid heat storage body 3 to heat the air by the heat released from the solid heat storage body 3, Reference numeral 5 is a heat exchanger for exchanging heat between air and water heated by the heat released from the solid heat storage body 6,
Is a hot water storage tank for storing hot water obtained by heating the water in the heat exchanger 5, 7 is a first circulation path connecting the heat exchanger 5 and the hot water storage tank 6, and 8 is a first circulation path 7 for storing water. A first pump to circulate, 9 is a water supply tap for discharging hot water stored in the hot water storage tank 6, 10 is a second circulation path connecting the hot water storage tank 6 and the water supply tap 9, and 11 is this second circulation path 10. A second pump that circulates hot water, 12 is a controller, 13 is a thermometer that measures the temperature of the solid regenerator 3 and sends the measurement result to the controller 13, 14
Is a thermometer that measures the temperature of the hot water flowing through the first circulation path 7 and sends the measurement result to the controller 13, and 15 is a flow meter provided in the water supply path 16 that supplies water to the hot water storage tank.

The controller 12 receives the information from the thermometer 11 and the thermometer 13, and controls the operation of the fan 4, the first pump 8 and the second pump 11. A method for controlling the temperature of hot water stored in the hot water storage tank 6 will be described.

Here, it is assumed that the solid heat storage body 3 has a standard heat storage temperature of 250 ° C. and can store heat at a temperature of up to 650 ° C. The temperature of the solid heat storage body 3 is, for example, 250 ° C.
Between ~ 650 ° C, the output of the heat storage type electric water heater is 100
% To 260%. At this time, the heat quantity on the solid heat storage body 3 side in the heat exchanger 5 is determined by the temperature of the solid heat storage body 3 and the air volume of the air sent by the fan 4. That is, when the amount of air sent by the fan 4 is large, the amount of heat increases and the hot water temperature can be raised. Further, the hot water temperature obtained on the water side is determined by a combination of the difference between the water temperature at the water inlet of the heat exchanger 5 and the hot water temperature at the water outlet and the flow rate of water.

When the controller 13 determines that the temperature of the solid heat storage body 3 is, for example, 250 ° C. to 650 ° C., the controller 13 operates while controlling the rotation speed of the fan 4 to supply air to the solid heat storage body 3 in Case 1. The air is heated by the heat released from the fed solid heat storage body 3. Further, the controller 13 operates the first pump 8 to circulate water between the heat exchanger 5 and the hot water storage tank 6 in the first circulation path 7 so that the solid heat storage body 3 is removed from the solid heat storage body 3 by the heat exchanger 5. Heat is exchanged with the air heated by the released heat. As a result, the temperature of the water is raised and the hot water storage tank 6
Stored in. The controller 13 operates the second pump 11 to circulate the hot water in the hot water storage tank 6 in the second circulation path 10. The hot water stored in the hot water storage tank 6 is discharged from the second circulation path 10 by operating the water tap 9.

Here, the thermometer 14 serves to measure the temperature of the water circulating in the first circulation path 7 and manage the hot water supply temperature. The controller 13 rotates the fan 4 at an appropriate number of revolutions so that the temperature of the hot water measured by the thermometer 14 becomes the hot water supply hot water temperature, pumps out heat from the solid heat storage body 3, and causes the heat exchanger 5 to operate. Heat the water. That is, the first pump 8
The temperature of the hot water in the hot water storage tank 6 and the heat exchanger 5 is always kept at a constant value by operating. The hot water supply temperature is controlled by continuously repeating this. The thermometer 14 may directly measure the temperature of the hot water storage tank 6.

The temperature of the solid regenerator 3 is, for example, 100 ° C. to 2
The output of the heat storage type electric water heater is 40% to 8 while the temperature is 50 ° C.
It is 0%. The controller 13 stops the rotation of the fan 4 and the first pump 8 when the temperature of the solid heat storage body 3 reaches, for example, 100 ° C to 250 ° C. As a result, in the hot water storage tank 6, a temperature stratification is formed between the water entering the hot water storage tank 6 from the water supply passage 16 and the water stored in the hot water storage tank 6. As a result, the hot water supply temperature becomes the same as the hot water temperature inside the hot water storage tank 6.

Here, the temperature stratification refers to an orderly temperature distribution in which the temperature of the hot water rises from the lower part of the tank to the upper part inside the hot water storage tank. In general, water is supplied to the bottom of the hot water storage tank to raise the temperature of the water below this temperature stratification.

Thereafter, when the controller 13 determines that water is being supplied to the hot water storage tank 6, it further stops the rotation of the fan 4 and the first pump 8. As a result, the hot water stored in the hot water storage tank 6 is not agitated and the temperature stratification of the hot water temperature is not disturbed. When the controller 13 determines that the hot water storage tank 6 is not supplied with water, the controller 13 stops the operation of the second pump 11. In addition, the controller 13 makes the water circulating through the first circulation path 7 circulate at a low speed so that the hot water stored in the hot water storage tank 6 is not agitated and the temperature stratification of the hot water temperature is not disturbed. The pump 8 is operated by controlling the rotation speed of the pump 8. At the same time, the fan 4 is operated by controlling the rotation speed so that an appropriate output can be obtained. Stopping the operation of the second pump 11 reduces heat loss.

By operating the first pump 8 at a low speed, the temperature of the solid heat storage body 3 is lowered, and even if the output is less than 100%, the heat exchanger 5 can sufficiently exchange heat.
This is because the heat exchange capacity of the heat exchanger 5 depends on the flow rate of water and the heat exchanger 5.
This is due to the product of the difference between the water temperature at the water inlet and the hot water temperature at the water outlet.

When the temperature of the solid regenerator 3 becomes less than a certain height in this way, the rotation of the first pump 8 is stopped so that the hot water stored in the hot water storage tank 6 is subjected to temperature stratification. Can be formed.

When water is supplied to the hot water storage tank 6 when the temperature of the solid heat storage body 3 is less than a certain height, the rotation of the fan 4 and the first pump 8 is stopped so that the hot water is stored in the hot water storage tank 6. It does not occur that hot water is agitated and the temperature stratification of hot water temperature is destroyed.

When the temperature of the solid heat storage body 3 is less than a certain height and water is not supplied to the hot water storage tank 6, rotation of a range in which hot water stored in the hot water storage tank 6 is circulated at a speed that does not agitate By rotating the first pump 8 at a speed and rotating the fan 4 at a rotational speed according to the temperature at which the hot water stored in the hot water storage tank 6 is to be obtained, the hot water stored in the hot water storage tank 6 is It is possible to raise the temperature of the water below the temperature stratification to a predetermined temperature without being stirred and destroying the temperature stratification.

In this way, when the temperature of the solid regenerator 3 is lower than a certain height and the output is low, the amount of heat on the side of the solid regenerator increases in proportion to the increase in the air volume due to the increase in the rotation speed of the fan 4. Without doing so, appropriate operation control of the fan 4 and the first pump 8 is performed according to the situation that the hot water temperature cannot be raised in proportion to the increase in the rotation speed of the fan 4. Thereby, the heat released from the solid heat storage body 3 is effectively consumed to obtain a predetermined hot water temperature, and the fan 4 and the first pump 8 are effectively operated to obtain the predetermined hot water temperature, You can drive economically without waste.

Therefore, when the temperature of the solid heat storage body 3 is lower than a certain height and the output is low, the operation control of the fan 4 and the first pump 8 according to this situation is performed, and the solid heat storage body 3 stores the heat. While effectively using heat to obtain the required hot water temperature,
The operation of the fan 4 and the first pump 8 can be economically performed. The present invention is not limited to the above-mentioned embodiment,
It is possible to carry out various modifications.

[0028]

As described above, according to the hot water supply temperature control method of the heat storage type electric hot water supply device of the present invention, the rotation of the fan and the pump at the time when the temperature of the solid regenerator is below a certain height. By stopping the operation, temperature stratification can be formed in the hot water stored in the hot water storage tank.

Thereafter, when water is supplied to the hot water storage tank when the temperature of the solid heat storage body is lower than a certain height, the rotation of the fan and the pump is stopped to agitate the hot water stored in the hot water storage tank. It does not destroy the temperature stratification of the hot water temperature.

Alternatively, thereafter, when the temperature of the solid heat storage body is lower than a certain height and water is not supplied to the hot water storage tank, rotation of a range in which water is circulated at a speed that does not agitate hot water stored in the hot water storage tank The hot water stored in the hot water storage tank is stirred and the temperature stratification is destroyed by rotating the pump at a speed and rotating the fan at the number of rotations corresponding to the temperature at which the hot water stored in the hot water storage tank is to be obtained. However, the temperature of the water below the temperature stratification can be raised to a predetermined temperature.

In this way, when the temperature of the solid regenerator is lower than a certain height and the output is low, the amount of heat on the solid regenerator side does not increase in proportion to the increase in the air flow rate due to the increase in the rotation speed of the fan. As a result, appropriate operation control of the fan and the pump is performed according to the situation that the hot water temperature cannot be raised in proportion to the increase in the rotation speed of the fan. As a result, the heat released from the solid heat storage body is effectively consumed to obtain a predetermined hot water temperature, and the fans and pumps are effectively operated to obtain the predetermined hot water temperature, which is economical without waste. You can drive.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a heat storage type electric water heater as an embodiment of the present invention.

[Explanation of symbols]

 2 ... Heating element, 3 ... Solid heat storage element, 5 ... Heat exchanger, 6 ... Tank, 8 ... Pump, 11 ... Pump.

Claims (1)

[Claims] 1. A heating element, a solid heat storage body that is heated by the heating body to store heat, a fan that sends air to the solid heat storage body and is heated by the heat released from the solid heat storage body, and the solid body. A heat exchanger for exchanging heat between the air and water heated by the heat released from the heat storage body, a hot water storage tank for storing hot water obtained by heating water in the heat exchanger, and the heat In a heat storage type electric hot water supply device comprising a pump for circulating water between an exchanger and the hot water storage tank, and a water supply tap for discharging hot water stored in the hot water storage tank, a temperature at which the solid heat storage body has a certain height. In the above case, when the fan and the pump are rotated according to the temperature at which the hot water stored in the hot water storage tank is to be obtained, the temperature of the solid heat storage body becomes less than a certain height. With the fan and the po When the temperature of the solid heat storage body is less than a certain height and water is supplied to the hot water storage tank, the rotation of the fan and the pump is continuously stopped, and the solid heat storage body is stopped. When the temperature is less than a certain height and water is not supplied to the hot water storage tank, the pump is rotated at a rotation speed within a range in which the hot water stored in the hot water storage tank is circulated at a speed that does not agitate the hot water. A hot water supply temperature control method for a heat storage type electric hot water supply device, characterized in that the fan is rotated at a rotational speed according to a temperature at which hot water stored in the hot water storage tank is to be obtained.