JPH04244552A - Method of controlling electrical energization control type hot water heater - Google Patents

Abstract

PURPOSE:To simplify a configuration of an electrical energization control type hot water heater. CONSTITUTION:In a method for boiling up hot water within a hot water storing tank by utilizing a mid-night electrical power, hot water is detected by a sensor for sensing an amount of flowing-in water and a temperature of flowing-in water from a completion of a previous boiling-up operation, an amount of electrical power required for a next time boiling-up operation is calculated and then a required electrical energization time T is calculated in reference to the calculated electrical amount. When this required electrical energization time T is shorter than a length of a mid-night electrical power time range, the electrical energization starting is delayed from the starting time of the mid-night electrical power time range by this short amount. A high accurate electrical energization control can be carried out only with using a flow rate sensor and a water temperature sensor. A reduction of configuration cost of the electrical hot water heater can be attained. Its controlling content is simple.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a method of controlling an energization-controlled electric water heater that utilizes surplus electricity late at night.

0002

2. Description of the Related Art Electric water heaters were developed for the purpose of effectively utilizing surplus power generated by power companies late at night, and are now used in households. Recently, with the spread of electric water heaters, the time switches of electric water heaters in each household are turned on at the same time immediately after 11:00 p.m. (midnight in some areas), when the late-night electricity period begins. Immediately after that, peak demand for electricity tends to continue for a while. In addition, the amount of electric water heater used in each household varies depending on the household or season, so even if the power is turned on at the same time, the time when the temperature inside the water heater reaches a predetermined value may vary. Since the amount of hot water varies depending on the amount of hot water remaining, the time the water heater is turned on also varies.According to actual measurements by the electric power company, it takes 2 to 3 hours in the summer and 4 to 5 hours in the winter.
It's about time. Due to this situation, the late-night power supply period is from 11:00 p.m. to 7:00 a.m. the next morning, but the peak power demand is from 11:00 p.m. to 3:00 a.m. the next morning, and on the contrary, from 4:00 a.m. to 7:00 a.m. the next morning. During this period, electricity demand will decline, and at this point, a decline in power generation efficiency and power transmission efficiency has become a problem.

[0003] As a solution to this problem, an energization control type electric water heater has been developed that delays the power supply to the electric water heater until early in the morning (in the latter half of the late night power period). For example, the boiling temperature of an electric water heater is determined from the settings on the remote controller and the temperature of the water supplied to the hot water tank, and the energization time required to achieve this boiling temperature is delayed to the latter half of the late-night electricity period. There is a system that aims to suppress the peak load of late-night electricity. However, this method has the inconvenience that the settings on the remote controller may not match the actual usage unless the switch is changed to use less hot water in the summer and more water in the winter.

In order to solve the above-mentioned inconvenience, instead of manually changing the settings of the remote controller according to the season, a plurality of temperature sensors are installed in the hot water tank, and the temperature inside the hot water tank is determined from the outputs of these sensors. There is a system that predicts the amount of hot water that will be needed the next day based on the amount of heat remaining in the upper part of the hot water and automatically boils the hot water tank so that the appropriate amount of hot water at a predetermined temperature is obtained (Refer to Utility Model Publication No. 2-40438). .

[0005]

[Problems to be Solved by the Invention] However, the control method disclosed in Utility Model Publication No. 2-40438 requires a large number of temperature sensors to accurately detect the amount of heat remaining in the upper part of the hot water tank. , the cost is high and the control is complicated. Of course, if the number of temperature sensors is small, the accuracy of detecting the heat amount of the remaining hot water will be low, making it impossible to perform accurate control.

[0006]

[Means for Solving the Problems] A control method for an energization-controlled electric water heater according to claim 1 of the present invention is a control method for an electric water heater that uses late-night electricity to boil hot water in a hot water storage tank with a heater. When the late-night power period begins, each detector detects the inflow water volume and inflow water temperature since the last time boiling was completed, and the amount of electricity required for the next boil is calculated from the detected water volume and water temperature. , calculate the required energization time from this calculated amount of power, and if this required energization time is shorter than the midnight power period, the time to start energizing the heater is determined as follows:
It is characterized by delaying the start of the late-night power period by a time T corresponding to the difference between the total time of the late-night power period and the required energization time.

[0007] The control method for an energization-controlled electric water heater according to claim 2 of the present invention is the method for controlling an energization-controlled electric water heater according to claim 1, when the start time of the late-night power period has passed, and When water is supplied to the hot water tank during the time before the start of energization, the time T is recalculated by adding up the amount of newly supplied water and the temperature of the inflow water, and the time T when the energization starts is changed to midnight. This is characterized by delaying the start of the power period.

[0008]

[Operation] In the present invention, the amount of heat required to boil water (
Since the required energization time is calculated based on the amount and temperature of water that actually flows into the hot water storage tank, the required energization time can be calculated very accurately. Since the energization time period is set retroactively from the end of the late-night power supply by the required energization time, the water in the hot water storage tank can be reliably boiled. In addition, two sensors, an inflow water amount sensor and a water temperature sensor, are sufficient, and costs can be reduced.

[0009]

[Embodiment] An embodiment will be described below with reference to the drawings.

FIG. 1 is a sectional view of an energization control type electric water heater according to an embodiment of the present invention, and FIG. 2 is a flowchart showing control details.

In FIG. 1, a hot water storage tank 12 is installed inside a casing 10 of an electric water heater. Although not shown, a heat insulating material is attached to the outer periphery of the hot water storage tank 12. A heater 14 is provided at the bottom of the hot water tank 12. Water is supplied to this hot water storage tank 12 from a water supply pipe 16 via a flow rate sensor 18, a water supply electromagnetic valve 20, and a check valve 22. Note that the temperature of the water supply is detected by a water supply temperature sensor 24 provided in the middle of the water supply pipe 16. A float switch 26 is provided at the upper part of the hot water storage tank 12, and the control section 28 that receives the detection signal from the float switch 26 outputs a control signal to the water supply solenoid valve 20, thereby causing water to flow into the hot water storage tank 12. Water is supplied so that the water level is always at a predetermined level.

[0012] The hot water in the hot water storage tank 12 is supplied to the float type hot water supply port 2.
7. Hot water supply piping 4 via flexible pipe 30, pump 32, check valve 34, flow switch 36, and pressure switch 38
Supplied from 2. Note that this hot water supply pipe 42 is provided with an accumulator 40 . When the pressure detected by the pressure switch 38 falls below a predetermined pressure due to the opening of a hot water faucet in a place where hot water is required (for example, a bathroom, kitchen, etc.), the pump 32 is activated by a signal from the control unit 28 to supply hot water. Hot water is supplied to the points of demand. Note that even if the discharge amount of hot water at this demand point is reduced, the pump 32 is operated as long as the flow switch 36 detects the flow rate.

At the bottom of the hot water storage tank 12, an overheating preventer 44,
A boiling temperature sensor 46 is provided. Further, a water level detection sensor 4 is installed approximately in the middle of the hot water storage tank 12 in the height direction.
8 is provided, and when the water level in the hot water storage tank 12 is lower than the water level detection sensor 48, the pump 32 is kept in a non-operating state.

A drain pipe 52 having a drain valve 50 is connected to the bottom of the hot water storage tank 12 . At the top of the hot water tank 12,
An overflow pipe 54 is connected.

[0015] A method of controlling energization to this energization control type electric water heater will be explained with reference to FIG. 2. As described above, when hot water is sent from the hot water storage tank 12 to a point where hot water is required and the water level in the hot water storage tank 12 decreases, the water supply solenoid valve 20 opens and water flows into the hot water storage tank 12 from the water supply pipe 16. However, water is supplied so that the water level in the hot water storage tank 12 is always at a predetermined level. The amount of water supplied is continuously measured by a flow rate sensor 18. Furthermore, the temperature of the water supply is also continuously (or intermittently) measured by the water supply temperature sensor 24 . These water amount and water temperature data are accumulated and stored in the control unit 28. Note that even if cold water flows into the hot water storage tank 12, the low temperature layer and the high temperature layer exist in the hot water storage tank 12 separated into two layers without mixing, and a sufficiently high temperature is always supplied from the float type hot water supply port 27. The hot water is pumped out.

[0016] Eventually, when it comes to late night hours (for example, 11 p.m.; depending on the area, it is midnight; if it is late at night, it is, for example, 1 a.m.), the accumulated data of the water supply water temperature and the amount of water supply is Calculate the required energization time from The specific formula for this calculation can be set as appropriate, but
The time for energizing the heater 14 is set in the following manner so as to provide the amount of heat necessary to boil all of the newly inflowing water.

The required amount of heat H to be generated by the heater 14 is calculated by H=inflow amount×(boiling set temperature−inflow average temperature). The required energization time t is based on this required heat amount H, t = (required heat amount H) ÷ (heater capacity) ÷ (
860Kcal/KWh)÷(setting efficiency). The delay time T is calculated by subtracting this required power-on time t from the total length of the late-night power period of 8 hours (e.g. 8 hours from 11 p.m. to 7 a.m.), T = (8 hours) - (required power-on time t) Calculated by The energization start time is the time when this T time has elapsed from the late-night power start time (for example, 11:00 pm).

[0018] If hot water is newly used and water is supplied before the T time elapses after calculating the delay time T, add this new inflow amount to the above inflow amount, and then Recalculate the average temperature of the inflow water by taking into account the temperature of this new inflow water, calculate the required amount of generated heat H based on these inflow amounts and inflow average temperature, and further calculate the required energization time t and delay time T. Try again. Then, after this time T has elapsed, the heater 14 starts to be energized.

[0019] Since the amount of hot water consumed late at night is usually extremely small, after setting the delay time T at midnight, the delay time T due to the new inflow of water will be changed.
There is no need to perform the calculation again (method according to claim 1). However, according to the control method (method of claim 2) in which the calculation of T is re-calculated as described above, it is possible to perform more fine-grained control.

[0020] In the above explanation, the total length of the late-night time period and its start time (for example, 11:00 p.m.) are all examples, and the above times may be changed depending on the time set by each electric power company. Of course.

[0021] If the water does not come to a boil during the midnight hours the previous day due to a power outage, etc., the electricity may be started at the same time as the midnight hours start the next day.

[0022]

Effects of the Invention As is clear from the above explanation, the energization control type electric water heater of the present invention uses a sensor for detecting the amount of water supplied and a sensor for detecting the temperature of the supplied water to achieve extremely high accuracy. A high degree of control can be achieved. In this way, since the number of sensors is small, the control content is simple, and it is also possible to reduce the cost of the electric water heater.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an energization control type electric water heater.

FIG. 2 is a flowchart illustrating an example method.

[Explanation of symbols]

10 Casing 12 Hot water tank 16 Water supply pipe 18 Flow rate sensor 20 Solenoid valve for water supply 24 Water supply temperature sensor 26 Float switch 28 Control section 32 Pump 36 Flow switch 38 Pressure switch 42 Hot water pipe

Claims (2)

[Claims] Claim 1: In a control method for an electric water heater that uses late-night power to boil hot water in a hot water tank with a heater, at the start of the late-night power period, the amount of inflow water and the inflow water temperature from the time the previous boiling was completed are determined. Detected by each detector, calculate the amount of electricity required for the next boiling from the detected water amount and water temperature, calculate the required energization time from this calculated amount of electricity,
If this required energization time is shorter than the length of the late-night power period, the time point at which power is started to be applied to the heater is changed to the late-night power period for a time T corresponding to the difference between the total time of the late-night power period and the required energization time. A control method for an energization control type electric water heater characterized by delaying the start time. [Claim 2] In the control method for an energization-controlled electric water heater according to claim 1, the start time of the late-night power period has passed, and water is not supplied to the hot water tank during the time period before the start of energization. When the time T is calculated by adding up the new water supply amount and the inflow water temperature, the energization control type is characterized in that the time T is recalculated by adding up the new water supply amount and the inflow water temperature, and the energization start time is delayed by the time T from the start of the late night power time period. How to control an electric water heater.