JPH025987B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] High-temperature water from a hot water tank obtained from a late-night electric water heater,
This occurs when solar water heaters are used as an auxiliary heat source for electric water heaters that mix tap water and other city water to supply hot water at the desired temperature and capacity. This invention relates to a method of calculating the temperature of the water heater to be heated based on the outside air temperature and controlling the energization time of the electric heater to detect insufficient boiling.

[Conventional technology]

Conventionally, there have been electric water heaters that mix high-temperature water from a hot water storage tank obtained from late-night electric water heaters with city water such as tap water to supply hot water at a desired temperature and capacity.

For example, as shown in FIG. 3, an electric heater 2' is installed in a hot water tank 1', the temperature of the water supplied to the hot water tank 1' is detected by a temperature sensor 3', and based on the detected result, The controller 4' controls the power supplied to the electric heater 2' by the switch 5' until the high-temperature water and city water such as tap water are mixed to supply hot water at the desired temperature and capacity. In addition, a city water supply pipe 6' is connected to the hot water storage tank 1', and a city water faucet 7' is also provided to the hot water tank 10' to supply water.
In addition, the hot water faucet 9' of the hot water tank 10' is connected to the hot water tank 1'.
It was a late-night electric water heater with hot water piping 8' to supply high-temperature water to the area.

Therefore, the city water temperature is t ₀ ℃, the amount of city water to be mixed is v ₀ , the boiling temperature of the hot water tank is t ₁ ℃, the capacity of the hot water tank is v ₁ , and the desired temperature is t ₂ ℃, If the desired amount of hot water is v ₂ , then hot water of v ₁ , which is t ₁ ℃, and t _0
The boiling temperature _{t 1} ℃ to make hot water of _{v 2} at t ₂ ℃ by mixing city water of v ₀ , _{which is} −t ₀ ) + t ₂ ...(1), and if the capacity of the electric heater 2' is SKW, the desired energization time H time of the electric heater 2' is calculated by the following formula: H=v ₁ (t ₁ −t ₀ )/860S...Calculated using (2).

Then, in the controller 4', v ₁ , given in advance,
Based on t ₁ , t ₂ and t ₀ obtained from temperature sensor 3', t ₁
and H could be calculated.

Further, the controller calculates a time T for the hot water temperature in the hot water tank 1' to reach t ₁ °C from the calculated time H to the time Tf when the late-night power supply ends, and the controller 4
When the built-in clock reached a certain time T, the electric heater was energized via a switch 5, and was later turned off.

The A diagram in Figure 2 shows the change in time and water temperature in the hot water tank when controlled as described above, and based on the A diagram, the late-night electric water heater It was controlled.

[Problem that the invention seeks to solve]

However, when a solar water heater is adopted to save energy in place of such a conventional electric water heater, and a late-night electric water heater is used as an auxiliary heat source for the solar water heater, the hot water storage tank 1' is Instead of the city water that would have been supplied without a solar water heater connected, hot water heated by the solar water heater will now be supplied.

By the way, in conventional electric water heaters, the hot water tank 1'
The temperature detected by the temperature sensor 3' attached to the water was the city water temperature t ₀ , and the boiling temperature was calculated using equation (1) above based on that temperature. When a water heater is connected to hot water tank 1' and a late-night electric water heater is used as an auxiliary heat source, the temperature sensor attached to the hot water tank detects the hot water temperature _t3 from the solar water heater, and the conventional As with the electric water heater, the result calculated using the above equation (1) by simply substituting t ₃ for t ₀ resulted in the boiling temperature being set low. That is, the desired boiling temperature calculated using the city water temperature t ₀ when city water is taken in is t ₁ , and the desired boiling temperature calculated using the above equation (1) using the hot water temperature t ₃ supplied from the solar water heater. boiling temperature
If t ₁ ′, then t ₁ > t ₁ ′.

In addition, when calculating the time H required to energize the electric heater to reach the above boiling temperature using equation (2) above, the hot water temperature t ₃ from the solar water heater is replaced by the city water temperature t ₀ which is the water supply temperature. By substituting , the power-on time and end time of the late-night electric water heater can be calculated, but the low boiling temperature t ₁ ' causes insufficient boiling, making it impossible to put it to practical use.

If this state is illustrated, it will be as shown in the B diagram in FIG.

Therefore, in order to accurately calculate the boiling temperature and the required energization time for the electric heater, the present invention calculates the temperature of the water supplied to the hot water storage tank based on the outside air temperature, and calculates the boiling temperature t to be raised. ₁ is calculated, the energization time H to the electric heater is controlled by the hot water temperature _t3 supplied from the solar water heater, and the solar water heater is used and the late-night electric water heater is used as an auxiliary heat source. It is an object of the present invention to provide a control method for an electric water heater that does not cause insufficient boiling.

[Means for solving problems]

The present invention mixes high-temperature water from a late-night electric water heater with city water such as tap water, and adjusts the water supply temperature t to the late-night electric water heater so that a desired hot water temperature t ₂ and hot water capacity v ₂ can be obtained. ₀ is detected, the boiling temperature t ₁ and its capacity v ₁ are calculated as t ₁ = v ₂ − _{v 1} / v ₁ (t ₂ − t ₀ ) + t ₂ ...(1), and the above water supply is The electric water heater is controlled by calculating the time H for energizing the electric heater with the capacity S of the late-night electric water heater based on the temperature t ₀ as follows: H = v ₁ (t ₁ - t ₀ )/860S...(2) In , even if the late-night electric water heater is used as an auxiliary heat source for a solar water heater, the water supply temperature based on the outside air temperature ta is calculated for the boiling temperature of a late-night electric water heater without a solar water heater connected. t ₀ = ta + α ...(3) (α: constant value determined by season and region) In calculating the energization time, the water supply temperature t ₀ is calculated as t ₀ = t ₃ (4), and the temperature of hot water t ₃ supplied from the solar water heater to the late-night electric water heater is calculated as follows: This is a control method.

Hereinafter, the present invention will be explained based on the drawings.

FIG. 1 shows an embodiment of the present invention,
First, to explain the configuration, an electric heater 2 is installed in a hot water storage tank 1 to serve as a late-night electric water heater.The temperature of the water supplied to the late-night electric water heater is detected by a temperature detector 3, and the temperature of the water supplied to the electric heater 2 is detected by a controller 4. In a conventional electric water heater where the energization time is controlled by a switch 5,
The solar water heater 11 is connected to the hot water tank 1 so that the late-night power water heater is used as an auxiliary heat source for the solar water heater. This is done by detecting the temperature of the outside air and the temperature of the outside air with a temperature detector 6.

In addition, in the figure, 10 is a hot water tank, and hot water storage tank 1
High-temperature water is supplied from a hot water faucet 9 connected to a hot water supply pipe 8, and city water such as tap water is supplied from a city water faucet 7 through a city water pipe and mixed to obtain hot water at a desired temperature and capacity.

Therefore, as a method of controlling the boiling temperature t ₁ of the hot water storage tank 1 and the energization time H to the electric heater of the late-night electric water heater, a method of controlling the boiling temperature t 1 of the hot water storage tank 1 and the energization time H to the electric heater of the late-night electric water heater is provided. The temperature detector 3 detects the temperature _t3 of hot water supplied from the solar water heater 11, and the temperature detector 6 detects the outside air temperature ta℃ near the electric water heater 11, and the temperature is calculated based on these detected temperatures. Then, the boiling temperature _t1 of the late-night electric water heater and the energization time H to the electric heater 2 are set using the controller 4.
is calculated and controlled.

That is, the control method is accurate because the solar water heater 11, which is easily affected by the outside temperature, is connected and the boiling temperature _t1 is raised by the late-night electric water heater that serves as an auxiliary heat source for the solar water heater. To calculate the boiling temperature, use equation (1) above with no solar water heater connected, where the water supply temperature of the late-night electric water heater is set to the city water temperature t ₀ , and the water supply temperature is set to the outside air temperature ta.
Calculation based on the outside air temperature ta is based on the outside air temperature ta, where α is a constant value determined by the outside air temperature that changes depending on the season, for example, each month, and the outside air temperature that differs depending on the region. The relationship with temperature is approximately established by the following equation, t ₀ ≒ ta + α ... (3), and the boiling temperature in a late-night electric water heater is
t ₁ is calculated and controlled using equation (3) above.

Therefore, if α is stored in the microcomputer, the approximate city water temperature t ₀ relative to the outside temperature ta can be calculated.
The alternative feed water temperature will be easily calculated.
Next, the required energization time for the electric heater 2 according to the above boiling temperature t ₁ is determined by changing the water supply temperature of the late-night electric water heater to the hot water temperature t ₃ supplied from the solar water heater.
If the solar water heater is not connected,
This is a method in which t ₀ =t ₃ in equation (2) is calculated and controlled by the following equation: H=v ₁ (t ₁ −t ₃ )/860S (4).

Then, the boiling temperature t ₁ determined by these methods
By showing the relationship between the time T to be controlled and the hot water temperature t in the hot water storage tank using the required energization time H and the C diagram in FIG. 2, the above control is performed based on the C diagram. .

[Effect]

Therefore, as an auxiliary heat source for the solar water heater 11, high-temperature water is obtained by a late-night electric water heater using an electric heater 2 installed in the hot water tank 1, and mixed with city water to provide hot water at a desired temperature and capacity. In order to calculate the boiling temperature by the late-night electric water heater and the required energization time of the late-night electric power, the temperature of the hot water supplied from the solar water heater 11 is detected by the temperature sensor 3 attached to the hot water tank 1. In addition, the outside air temperature near the electric water heater made of the device is detected, and based on these detected temperatures, the controller 4 compares the outside air temperature with the stored outside air temperature that differs depending on the season and region. constant value and the hot water tank 1
The boiling temperature is determined by calculating the temperature of city water etc. supplied to the water supply system, and the required energization time to the electric heater 2 is calculated based on the temperature of the water supplied from the solar water heater 11, and the switch 5 is turned on. control.

The boiling temperature calculated using the above control method and the time controlled from the required energization time to the electric heater are shown in Figure 2 in relation to the water temperature in the hot water storage tank 1 and the outside air temperature. As shown in FIG. 2, the electric heater 2 is expressed in a C diagram, and the electric heater 2 is controlled by the controller 4 based on the C diagram.

〔Effect of the invention〕

As a result of the above, the present invention has developed a method for controlling a conventional electric water heater, which could not be put into practical use due to insufficient boiling when a late-night electric water heater, in which the electricity supply time to the electric heater is controlled, is used as an auxiliary heat source for a solar water heater. of,
The boiling temperature is calculated by detecting the outside air temperature with a temperature detector, and the power supply time to the electric heater is calculated as the water supply temperature of the hot water tank by detecting the temperature of the water from the solar water heater with the temperature detector. This is a convenient method that enables accurate energization of the electric heater and allows the late-night electric water heater to effectively function as an auxiliary heat source for the solar water heater installed to save energy.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the structure of an electric water heater in which a late-night electric water heater is used as an auxiliary heat source for the solar water heater of the present invention, and Fig. 2 shows the power supply time to the electric heater and hot water storage based on water supply temperature data. It is a relationship diagram of tank internal temperature. FIG. 3 is a structural explanatory diagram of a conventional electric water heater. 1, 1'... hot water tank, 2, 2'... hot water tank, 3,
3'... Temperature detector, 4, 4'... Controller, 5,
5'...Switch, 6,...Temperature detector, 6'...
Water supply piping, 7, 7'... City water faucet, 8, 8'... Hot water supply piping, 9, 9'... Hot water faucet, 10, 10'...
Hot water tank, 11... Solar water heater, H... Energization time, t ₁ ... Boiling temperature, t ₀ ... City water temperature, t ₃ ...
Water temperature, t ₁ '... Boiling temperature based on water temperature t ₃ , Tf... Time when power supply ends, T... Time when power supply starts for the clock built into the controller.

Claims (1)

[Scope of Claims] 1. High-temperature water from a late-night electric water heater is mixed with city water such as tap water, and water is supplied to the late-night electric water heater so as to obtain hot water with a desired hot water temperature t ₂ and capacity v ₂ . The feed water temperature t ₀ is detected, and the boiling temperature t ₁ and its capacity v ₁ are calculated as t ₁ = v ₂ − v ₁ /v ₁ (t ₂ − t ₀ ) + t ₂ , and the above feed water temperature t ₀ , the time H during which the electric heater with the capacity S of the late-night electric water heater is energized until the above boiling temperature is reached is calculated and controlled as H = v ₁ (t ₁ - t ₀ )/860S. Regarding electric water heaters, even if the above-mentioned late-night electric water heater is used as an auxiliary heat source for a solar water heater, the temperature will differ from the calculation of the boiling temperature of a late-night electric water heater to which a solar water heater is not connected.
Calculate the water supply temperature t ₀ = ta + α (α: constant value determined by season and region) based on ta, and when selecting the energization time H of the electric heater, Regarding the calculation of the energization time, the electric water heater control method calculates the water supply temperature t ₀ as t ₀ = t ₃ and the hot water temperature t ₃ supplied from the solar water heater to the late-night electric water heater. .