JPH0527016B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to heater energization control of a hot water storage type electric water heater using late-night electricity. Configuration of conventional example and its problems As shown in Fig. 1, this type of conventional electric water heater has a water supply temperature detection means 3' installed in a water supply pipe 2' connected to a hot water storage tank 1', A heat amount calculation means 5' calculates the amount of heat to be added from the preset value set by the hot water amount setting means 4', and a heat amount calculated by the heat amount calculation means 5' based on the detection value detected by the supply water temperature detection means 3'. a temperature detection means 7' for detecting the temperature of the hot water storage tank; and an energization control means 9' for controlling the energization to the late-night power heater 8' based on the difference in power. In this configuration, the set value set by the hot water amount setting means 4' is rarely changed every day, and is set at the maximum so as not to run out of hot water, so heat radiation loss due to residual hot water is not reduced. In order to prevent this, the customer must make settings while checking the status of remaining hot water every day, which is as inconvenient as manual setting. Purpose of the invention The present invention solves such conventional problems,
The purpose is to determine the appropriate boiling temperature and reduce energy loss. Structure of the Invention In order to achieve this object, the present invention provides a late-night power heater installed in a hot water storage tank, a temperature detection means for detecting the temperature of hot water in the hot water storage tank, and a temperature detecting means for detecting the temperature of water supplied to the hot water storage tank. A water temperature detection means for detecting water temperature, a hot water amount setting means for arbitrarily setting in advance the amount of hot water to be used with respect to the amount of hot water stored in the hot water storage tank, an energization detection means for detecting the energization time to the late-night power heater, and an energization detection means for a certain period of time. a storage means for storing a signal from the storage means, and obtaining a water heating heat amount result based on the signal of the storage means,
a calculation means for calculating the boiling temperature by dividing the actual water supply heat amount by the amount of hot water used from the hot water amount setting means and adding the water supply temperature from the temperature detection means, and a signal from the calculation means and the temperature detection means; and energization control means for controlling energization to the late-night power heater. With this configuration, the actual amount of heat for hot water supply is determined from the current-on time for a certain period in the past in the storage means, and the boiling temperature is calculated so that this actual amount of hot water supply matches the amount of heat at the preset amount of hot water used. By controlling the energization of the heater for late-night electricity based on this, the set hot water temperature and the actual amount used almost match. DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. A late-night power heater 2 installed inside the hot water tank 1, a temperature detection means 3 installed above the late-night power heater 2 to detect the temperature of the hot water tank, and a water temperature of a water supply pipe 4 connected to the lower part of the hot water tank 1. Water temperature detection means 5
and a hot water amount setting means 6 for arbitrarily setting in advance the amount of hot water to be used in consideration of the amount of hot water stored in the hot water storage tank 1.
, an energization detection means 7 for detecting the energization time to the late-night power heater 2, a storage means 8 for storing signals from the energization detection means 7 for a certain period, and a hot water amount and water temperature detection set by the hot water amount setting means 6. A calculation means 9 calculates the required boiling temperature based on the signal from the means 5 and the signal from the storage means 8, and a late-night power heater 2 according to the signals from the calculation means 9 and the temperature detection means 3.
The calculation means 9 includes a selection section 11 that selects the maximum value from a certain period of energization time obtained by a signal from the storage means 8; 11, a set value of the hot water amount setting means 6, and a signal from the water temperature detecting means 4, a calculation section 1 calculates the required boiling temperature.
2 is provided. In addition, 13 is a hot water pipe, 14
is a timer for late-night power. In the above configuration, the hot water in the hot water storage tank 1 is supplied at a time limited by the late-night power timer 14.
The energization control means 10 energizes the late-night power heater 2 based on the difference between the signal from the temperature detection means 3 and the required boiling temperature signal calculated by the calculation means 9 to heat it, and discharges hot water from the hot water pipe 13 as necessary. At the same time, water is supplied from the water supply pipe 4 to the hot water storage tank 1. This required boiling temperature is set as shown below. The energization detection means 7 detects the energization time of the late-night power heater 2 every day, and the energization time for a certain period (for example, one week) up to the previous day is stored in the storage means 8, and the selection section 11 stores the energization time for a certain period (for example, one week) up to the previous day. The maximum value is selected from the energization time for a certain period obtained by the means 8, and the calculation unit 12 calculates the actual amount of heat of refueling from the maximum value,
Based on the signal, the boiling temperature is calculated so that the actual amount of heat for hot water supply matches the amount of stored hot water at the amount of hot water used. The maximum value indicates the energization time on the maximum hot water supply day during a certain period up to the previous day, and this value converted into heat amount is taken as the actual hot water heat amount. The reason for using the maximum value is to absorb variations in the amount of hot water used. Calorie conversion is based on Equation 1. Hot water heating performance = η×q×Hmax×860 (kcal/h)
Equation 1 Where: η: Heating efficiency q: Heater capacity (W) Hmax: Maximum value of energization time for a certain period (h) The boiling temperature is set so that the above-mentioned hot water supply heat value and the stored hot water heat value at the set amount of hot water used match. Calculated using equations 2 and 3. V _S shown here is the amount of hot water used relative to the amount of stored hot water set by the hot water amount setting means 6. This formula (actual amount of hot water heating/V _S )
is the required amount of heat divided by the set amount of hot water, and represents the required temperature rise value to obtain the required amount of heat at V _S. Therefore, adding the feed water temperature _TW to this required temperature increase value will give the boiling temperature. Actual heat amount of hot water supply = V _S × (T _S − T _W ) (kcal/h) Formula 2 Therefore, T _S = T _W + Actual calorific value of hot water supply/V _S (°C) Formula 3 Where, T _S : Boiling temperature ( ) T _W : Water supply temperature (°C) V _S : Amount of hot water used () V _S is the set value for the amount of hot water used (hot water storage tank 1
(capacity) - V _S is the set value for the amount of remaining hot water; if V _S is made small, the remaining hot water can be used with a large amount of leeway, and if V _S is made large, hot water can be heated economically although there is less leeway. Next, the control operation will be explained using the flowchart shown in FIG. In the figure, the control starts at the same time as the late-night power timer 14 starts energizing the late-night power at 15, the water temperature T W detected by the water temperature detection means 5 is taken in at 16, and the water temperature T _W detected by the water temperature detection means 5 is taken in at 17. The set value V _S is read. At 18, the energization time H for several days stored in the storage means 8 is read from 19, the maximum value Hmax of the energization time H is selected, and the required boiling temperature T _S is calculated at 20 based on this Hmax. At 21, the hot water temperature Th detected by the temperature detection means 3 is taken in, and at 22, T _S and Th
If Th has not reached T _S , the late-night power heater 2 will be energized at 23, and if Th has reached T _S , the power will be turned on at 23.
Turn off the power at step 4. 25 detects the energization time H when the late-night power heater 2 is energized, and sends the detection result to the storage means 8. The heater on/off control in steps 22 to 25 from the intake of the hot water temperature Th in step 21 is repeated until the midnight power timer 14 stops the power supply in the middle of the night. Here, the water supply temperature is 5 (℃) and the capacity of hot water tank 1 is 370.
(), will be explained based on the hot water supply usage conditions assuming operation at a capacity of the heater 2 of 4.4 (kw). However, to simplify the explanation, the heating efficiency was assumed to be 100%. In addition, the upper limit of the required boiling temperature T _S is 85 (℃),
If the memory value is not filled in the memory means 8,
Let T _S be 85°C. The storage period of the storage means 8 is assumed to be three days. Table 1 shows the operation when the amount of hot water used V _S is set to 300 (), and Table 2 shows the operation when V _S is set to 270 (). Here, in the column for hot water heating capacity in the table, the numbers in parentheses indicate the hot water temperature in the upper row and the daily amount of hot water in the lower row (in parentheses).
The hot water temperature is 45°C. In other words, since the water supply temperature is 5°C, the calorific value of hot water supply is calculated as follows: Hot water supply amount = hot water supply amount x (45-5) (kcal/day). The storage means 8 stores the energization time up to the previous day as shown in a table while being updated sequentially. The required boiling temperature is calculated based on Equation 3, but here the efficiency is
It is set to 1.0. The remaining amount of hot water is the stored hot water amount {370×(T _S −
5)} is the value obtained by subtracting the amount of heat for hot water heating on the previous day. However, heat radiation was ignored. The power supply time is the time required to boil 370 () to _TS including the heat of the remaining water. As shown in the table below, you can see that T _S is automatically set according to the heat amount of hot water from the fourth day onwards. Also, V _S is 300
Compared to 270, T _S is higher and the amount of remaining hot water is larger.

【table】

【table】

[Table] As described above, the required boiling temperature is determined based on the amount of hot water set by the user using the hot water amount setting means and the maximum value selected from the energization time for a certain period. Changes in temperature, etc.
In addition, it is possible to appropriately heat up the hot water supply load, which varies depending on the usage status of the hot water, reducing the amount of remaining hot water and reducing energy loss. Effects of the Invention As described above, the electric water heater of the present invention provides the following effects. (1) The required boiling temperature is calculated and controlled from the water supply temperature for the set amount of hot water and the energization time for the late-night power heater for a certain period of time, so the boiling temperature matches the actual usage conditions and energy is wasted due to wasted heating. This has the effect of reducing loss. (2) Since the amount of heat to be added is known from the energization time for a certain period of time, there is no uncertainty as determined by daily control means, and it is convenient because the optimum water temperature can be automatically set. is good. (3) It is possible to arbitrarily set the usage amount in advance with allowances for the amount of hot water stored, and the boiling temperature is calculated so that the hot water supply record and the set usage amount match, so it is possible to store hot water with sufficient margin and save money. You can freely choose the desired hot water storage level, and there is no need for unnecessary boiling.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional electric water heater, FIG. 2 is a block diagram of an electric water heater according to an embodiment of the present invention, and FIG. 3 is a control flowchart of the electric water heater. 1...Hot water tank, 2...Heater for late night electricity, 3...
. . . temperature detection means, 5 . . . water temperature detection means, 6 . . . hot water amount setting means, 7 .

Claims (1)

[Claims] 1. A late-night power heater installed in the hot water storage tank, a temperature detection means for detecting the temperature of hot water in the hot water storage tank, a water temperature detection means for detecting the temperature of water supplied to the hot water storage tank, and a temperature detection means for detecting the temperature of water supplied to the hot water storage tank, and a hot water amount setting means for arbitrarily setting the amount of hot water to be used in advance; and an energization detection means for detecting the time period during which the late-night power heater is energized;
A storage means for storing signals from the energization detection means for a certain period of time, and calculating the actual amount of heat for hot water supply based on the signal of the storage means, dividing the actual amount of hot water for heating by the amount of hot water used, and adding the temperature of the supplied water to boil the water. An electric water heater comprising a calculation means for calculating temperature, and an energization control means for controlling energization to the late-night power heater based on signals from the calculation means and the temperature detection means.