JPH05157352A - Electrical hot water supply apparatus - Google Patents

Abstract

PURPOSE:To eliminate wasteful electric discharge loss by executing boiling temperature conversion by a boiling temperature circulation part besed upon a hot water supply heat amount of a standard hot water supply pattern estimated from a past hot water supply pattern and upon a hot water supply temperature, and performing power supply control to an electric heater in midnight power based upon the converted boiling temperature. CONSTITUTION:A calculation part 16 estimates boiling temperature based upon a hot water supply heat amount estimated by a standard pattern setting part 12 from a past hot water supply pattern stored in a hot water supply pattern storage part 11 and based upon hot water supply temperature fed from hot water supply temperature detector means 4. A comparator part 17 compares the estimated value with boiling temperature detected by boiling temperature detector means 3 and controls power supply to an electric heater 2 disposed in a hot water storage layer 1 through midnight power supply control means 19 in response to the comparison result. Further, a comparison part 13 compares a standard hot water supply pattern estimated by daytime power supply control means 15 from a past hot water supply pattern with a preset hot water supply pattern estimated by a hot water supply pattern estimation part 9, and supplies when a hot water supply heat amount exceeds a standard value the daytime power to the electric heater 2 only by an exceeding heat amount.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art This kind of electric water heater corresponds to the electricity rate system set by an electric power company for the purpose of suppressing and leveling down the fall of electric power demand at midnight. That is, the water in the hot water storage tank is boiled and kept warm by the cheap electric power at midnight. However, this type of electric water heater has a risk that if the amount of hot water used is extremely large, the hot water in the hot water storage tank will be exhausted and hot water cannot be supplied. In order to prevent this hot water shortage, you can enlarge the hot water tank, but if you happen to use hot water for two or more times of bathing, or if the water usage of a rare visitor suddenly increases, you should enlarge the hot water tank. A large amount of hot water was left over during normal hot water supply, increasing heat loss due to heat radiation from the hot water storage tank, resulting in poor efficiency.

Therefore, as a method for coping with a sudden increase in the amount of hot water supplied without making the hot water storage tank large, it has been practiced to use daytime electric power for boiling. As shown in FIG. 3, this is a hot water storage tank 51, an electric heater 52 provided under the hot water storage tank, a boiling temperature detecting means 53 for detecting the boiling temperature of the hot water storage tank, and a boiling temperature detecting means 53. Of the electric heater 52 so that the signal of is equal to the value preset by the boiling temperature setting unit 59.
Power energization control means 54 for controlling energization, a timer 55 for detecting a midnight power energization time zone, a midnight power energization control means 56 for enabling the electric heater 52 to be energized only in the midnight power time zone, and a daytime power The electric hot water supply includes an energization setting unit 57 for setting the energization time according to the above, and a daytime electric power energization control unit 58 that enables the electric heater 52 to be energized for a set time according to an instruction of the energization setting unit 57 even during a period other than the midnight power energization time period It is a device.

[0004]

However, in the above-mentioned conventional configuration, it is not known how much the energization time of the daytime electric power should be set, so that the setting is made for a long time and the use of the expensive daytime electric power is increased. The electricity charges will be high. In addition, if the amount of hot water supply suddenly increases without forgetting the setting, there is a problem that even if the power is turned on during the day, the heating may not be in time and the hot water may run out. It was Further, if the boiling temperature is set too low, hot water tends to run out, and the frequency of reheating by the expensive daytime power increases. On the other hand, if it is too high, the usage rate of midnight power will increase,
The amount of heat dissipation increases, and the efficiency decreases.

The present invention has been made to solve the above problems, and an object of the present invention is to prevent hot water shortage while efficiently and economically energizing midnight power and daytime power supply.

[0006]

In order to achieve the above object, the present invention comprises a hot water storage tank, an electric heater provided in the lower portion of the hot water storage tank, and a boiling temperature detecting means for detecting the boiling temperature of the hot water storage tank. A hot water supply temperature detecting means for detecting a hot water supply temperature to the hot water storage tank, a hot water discharge temperature detecting means for detecting a hot water discharge temperature from the hot water storage tank, a hot water supply flow rate detecting means for detecting a water supply amount to the hot water storage tank, A hot water supply heat amount calculation unit for calculating a heat supply amount of hot water from signals of the water supply temperature detection unit, a hot water temperature detection unit, and a hot water supply flow amount detection unit, and a hot water supply pattern for obtaining a temporal pattern of the hot water supply heat amount by a calculation result of the hot water supply heat amount calculation unit and a timer A calculation unit; a hot water supply pattern storage unit that stores signals of the hot water supply pattern calculation unit; a standard pattern setting unit that sets a standard hot water supply pattern from the stored contents of the hot water supply pattern storage unit; A pattern comparison unit that compares the signal from the turn calculation unit and the signal from the standard pattern setting unit to calculate the amount of heat of the difference between the standard hot water supply pattern, and the electricity by daytime power according to the amount of heat of the difference of the pattern comparison unit. Daytime electric power energization control means for energizing the heater, and hot water supply heat quantity and water supply temperature detection means 4 set by the standard pattern setting section 4
Of the boiling temperature calculation unit for calculating the required boiling temperature according to the signal of, and the electric power generated by the midnight power according to the deviation between the temperature signal from the boiling temperature detection unit and the calculation signal from the boiling temperature calculation unit. The configuration is such that a midnight power energization control means for energizing the heater is provided.

[0007]

According to the present invention, with the above-described structure, the standard pattern setting unit converts the hot water supply heat amount of the standard hot water supply pattern calculated from the hot water supply patterns from the past into the boiling temperature by the temperature calculation unit, and the midnight power is calculated based on this boiling temperature. The energization of the electric heater is controlled by. On the other hand, the standard hot water supply pattern calculated from the hot water supply pattern from the past and the current hot water supply pattern obtained by the hot water supply pattern calculation unit are compared, and if the hot water supply heat amount exceeds the standard, the heating amount by daytime power is calculated from the exceeded heat amount. , The electric heater operates so as to control energization.

[0008]

Embodiments of the present invention will be described below with reference to FIGS.

In FIG. 1, 1 is a hot water storage tank, 2 is a hot water storage tank 1.
An electric heater 3 provided in the lower part of the electric heater 3 is provided above the electric heater 2 to detect a boiling temperature detecting means for detecting the temperature of the hot water in the hot water tank 1.
Is a water supply temperature detecting means for detecting the water supply temperature provided in the water supply pipe 5 to the hot water storage tank 1, 6 is a hot water discharge temperature detecting means for detecting the hot water discharge temperature provided near the hot water discharge pipe of the hot water storage tank 1, and 7 is a flow rate of the water supply pipe 5. The hot water supply flow rate detecting means for detecting 8 is a hot water supply heat quantity calculating section for calculating the hot water supply heat quantity from the signals of the hot water supply temperature detecting means 4, the hot water discharge temperature detecting means 6, and the hot water supply flow rate detecting means 7, and 9 is a calculation result of the hot water supply heat quantity calculating section 8. A hot water supply pattern calculation unit that calculates the hourly integration pattern of the hot water supply heat amount for one day by adding up the time of the daily timer 10 as a 24-hour timer, and 11 stores the hourly integration pattern of the hot water supply pattern calculation unit 9 for one week. The hot water supply pattern storage unit to be updated, 12 is a standard pattern setting unit that sets the hourly integration pattern of the standard hot water supply heat quantity from the hot water supply pattern storage unit 11, and 13 is the calculation result of the hot water supply pattern calculation unit 9 and the standard pattern. The pattern comparison unit that compares the set value of the power setting unit 12 and calculates the amount of heat of the difference when the calculation result exceeds the set value. When the detection signal of the daytime detection timer 14 is input and the calculated value of the amount of heat of difference is input from the pattern comparison unit 13, the electric heater is output from the calculated value. The energization time of 2 is converted, and the electric heater 2 is energized for the converted time. Reference numeral 16 denotes a boiling temperature calculation unit that calculates a required boiling temperature according to the integrated heat quantity of the standard hot water supply pattern set by the standard pattern setting unit 12 and the signal of the water supply temperature detection means 4.
Reference numeral 17 is a temperature comparison unit that compares the signals of the boiling temperature detection unit 3 and the boiling temperature calculation unit 16 and outputs an energization signal when the detected temperature is low, and 18 is a midnight detection that outputs a detection signal during the midnight power energization time zone. A timer, 19 is a midnight power energization control unit, which energizes the electric heater 2 when the midnight detection timer 6 detects the midnight power energization time zone and inputs the energization signal of the temperature comparison unit 17, and a hot water supply calorie calculation unit. The heat quantity for hot water supply in No. 8 is calculated by the following equation.

Q = W · (To-Ti) However, Q: Hot water supply heat quantity (kcal / h) W: Hot water supply flow rate (l / h) To: Hot water temperature (° C) Ti: Hot water temperature (° C) Hot water supply pattern calculation unit In 9, the calculated values of the hot water supply heat amount calculation unit 8 are integrated as in the following (Equation 1).

[0011]

[Equation 1]

However, Q (i): Hot water supply heat quantity (kcal / h) at time i calculated by the hot water supply heat quantity calculation unit 8 Δt: Calculation time interval (h) The integration here is from 3:00 to 23:00. , The integrated value is reset at 3 o'clock. Further, the hot water supply pattern storage unit 11 stores the calculated value of the hot water supply heat amount calculation unit 8 for the past 7 days. This leaves only the latest calculated value, discarding values before 8 days.

The standard pattern setting unit 12 excludes the maximum day value of the integrated heat quantity from the stored values of the hot water supply pattern storage unit 11 for one week, and obtains the maximum value by time from the values of the remaining 6 days.
Then, considering the temporal variation and the calorific variation, the maximum value for each time is advanced by a certain time, and the heat amount is added by a certain value. The value obtained as a result is used as a standard hot water supply pattern.

This standard hot water supply pattern will be described with reference to FIG. 20 is a hot water supply heat amount calculated by the hot water supply heat amount calculation unit 8, 21 is a hot water supply pattern obtained by integrating the hot water supply heat amount 20 by the hot water supply pattern calculation unit 9, and 22 to 25 are hot water supply patterns on different days. Are stored in the hot water supply pattern storage unit 11. The standard pattern setting unit 12 excludes the hot water supply pattern 25 on the day with the maximum accumulated heat amount from these hot water supply patterns. This is because the hot water supply data is excluded as standard data for standard setting. Then, the maximum value 26 for each time of the remaining hot water supply patterns 21 to 24 is obtained. Next, the standard hot water supply pattern 27 is set by shifting the time and the amount of heat at regular intervals. This time shift amount is advanced by 1.5 hours in consideration of temporal variations. The transfer amount of the hot water supply heat amount is determined to be 10% higher than the final integrated value of the maximum value 26 for each time. Reference numeral 28 denotes a hot water drain limit value, which is used to supply hot water without reheating by daytime power, and when the integrated value exceeds this value, hot water drainage occurs. This value is calculated by the following formula.

QL = η × V × (Ts-Tc) where QL: Hot water drain limit value (kcal) η: Hot water storage efficiency V: Hot water storage amount (liter = kcal / ° C.) Ts: Boiling temperature (° C.) Tc: The water supply temperature (° C.) pattern comparison unit 13 compares the time-based integrated pattern of the hot water supply heat amount calculated by the hot water supply pattern calculation unit 9 with the standard pattern set by the standard pattern setting unit 12, and the time-based calculation pattern is the standard pattern. If it exceeds, the calorific value of the exceeded difference is calculated. For example, assuming that 100 liters of hot water is used at 85 ° C. by 8 am and the water supply temperature is 10 ° C., the amount of heat supplied from the hot water is 7500 kcal. On the other hand, if the standard pattern setting unit 12 sets 6500 kcal, the difference is calculated to be 1000 kcal.

The daytime power energization control means 15 energizes the electric heater when the difference heat quantity is input from the pattern comparison section 13 in a time zone outside the midnight power energization time zone. Using the above example, if a difference of 1000 kcal occurs at 8:00 am, this heat quantity is converted into energization time by the following equation.

H = ΔQ / W + 860 = 1000/4 × 860 = 0.29 (17 minutes) However, H: energization time (h) ΔQ: heat quantity of difference (kcal) W: capacity of electric heater (W) where The energization of the electric heater 2 is controlled only for the calculated energization time of 17 minutes. However, in this case, the control is stopped so that the detected value of the boiling temperature detecting means 3 does not exceed the upper limit temperature (for example, 85 ° C.) during boiling. In addition, when hot water supply further occurs and the difference heat amount increases, the energization time is controlled to be extended by the increased amount.

The boiling temperature calculation unit 16 has an integrated heat quantity 29 of the standard hot water supply pattern 27 set by the standard pattern setting unit 12.
From this, the boiling temperature for supplying this amount of heat is calculated using the following equation.

Ts = Tc + Qb / η × V where Ts: boiling temperature (° C.) Tc: water supply temperature (° C.) Qb: integrated heat quantity (kcal) of standard hot water supply pattern η: hot water storage efficiency V: hot water storage capacity (liter = kcal / According to the configuration of this embodiment, when the normal hot water supply such as 21 to 24 is performed with the value set by the standard pattern setting unit such as 27 in FIG. 2 as a reference, the hot water supply pattern exceeds the standard value. Since there is no electricity, the electric heater is not energized by daytime electricity, and hot water is supplied only by nighttime electricity, which is economical. On the other hand, when the sudden increase in the hot water supply amount such as the occasional morning bath as in 25 occurs, the hot water supply is performed at the time when the sudden hot water supply occurs (the hot water supply heat amount 25 exceeds the standard pattern 27 at 8:00). Since the amount exceeds the standard pattern, the excess power is reheated by daytime electricity, and there is no worry of running out of hot water. At this time, if the reheating by daytime electric power is not performed, the integrated value 25 becomes the hot water limit value 2 at the stage of 19:30.
Since it exceeds 8, hot water runs out.

Further, since the set value is changed daily by the hot water supply standard pattern setting unit 12, the change can be automatically coped with even when the normal hot water supply use state changes.

[0021]

As described above, in the electric hot water supply apparatus of the present invention, the boiling temperature calculation unit is based on the hot water supply heat amount of the standard hot water supply pattern calculated by the standard pattern setting unit from the hot water supply pattern from the past and the signal from the hot water supply temperature detecting means. Due to boiling temperature h
Since it is converted and the energization of the electric heater is controlled by the midnight power based on this boiling temperature, the boiling temperature can be controlled according to the amount of heat actually used, and efficient hot water supply without wasteful heat radiation loss can be performed.

The standard pattern setting unit compares the standard hot water supply pattern calculated from the hot water supply patterns from the past with the current hot water supply pattern obtained by the hot water supply pattern calculation unit,
When the hot water supply heat amount exceeds the standard, the heating amount by daytime electricity is calculated from the exceeded heat amount and the electric heater is energized to control, so in normal hot water use below the standard hot water supply pattern, only the late night electricity is economical to boil. You can On the other hand, when hot water is used in excess of the standard hot water supply pattern, such as occasional morning baths or sudden hot water supply by visitors, excess power is reheated by daytime electricity, and there is no worry of running out of hot water.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an electric water heater according to an embodiment of the present invention.

FIG. 2 is a hot water supply characteristic diagram of the above embodiment in a hot water supply use state.

FIG. 3 is a configuration diagram of a conventional electric water heater.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hot water tank 2 Electric heater 3 Boiling temperature detection means 7 Midnight electric power energization control means 4 Water supply temperature detection means 6 Hot water temperature detection means 7 Hot water flow rate detection means 8 Hot water quantity calculation part 9 Hot water pattern calculation part 10 Day timer 11 Hot water pattern storage Part 12 Standard hot water supply pattern setting part 13 Pattern comparison part 15 Daytime power supply control means 16 Boiling temperature calculation part 19 Midnight power supply control means

Claims (1)

[Claims] 1. A hot water storage tank, an electric heater provided at a lower portion of the hot water storage tank, a boiling temperature detecting means for detecting a boiling temperature of the hot water storage tank, and a water supply temperature for detecting a water supply temperature to the hot water storage tank. Detection means, hot water temperature detection means for detecting hot water temperature from the hot water storage tank, hot water supply flow rate detection means for detecting water supply amount to the hot water storage tank, the hot water temperature detection means, hot water temperature detection means, hot water flow rate detection Means for calculating the heat quantity of hot water supply from the signal from the means, a hot water supply pattern calculation section for obtaining a temporal pattern of the heat quantity for hot water supply by a calculation result of the heat quantity calculation for hot water supply and a timer, and a signal of the hot water supply pattern calculation section are stored. Hot water supply pattern storage unit, a standard pattern setting unit that sets a standard hot water supply pattern from the stored contents of the hot water supply pattern storage unit, a signal from the hot water supply pattern calculation unit, and the standard pattern setting A pattern comparing unit that calculates a heat quantity of a difference from the standard hot water supply pattern by comparing the signal from the, and a daytime electric power energization control unit that energizes the electric heater by daytime electric power according to the heat quantity of the difference of the pattern comparing unit; A boiling temperature calculator that calculates a required boiling temperature according to the amount of hot water supplied by the standard pattern setting unit and a signal from the water temperature detector 4, a temperature signal from the boiling temperature detector, and the boiling temperature calculator. An electric hot water supply device comprising a late-night power energization control means for energizing the electric heater by means of late-night power in accordance with a deviation from a calculated signal from the section.