JPH0252780B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention utilizes low-cost late-night electricity,
This invention relates to an electric water heater that uses nighttime electricity and is configured to boil a constant amount of water at a constant temperature during the night.

This type of electric water heater, which is currently popular, supplies a fixed amount (hot water storage tank capacity) of hot water at a constant temperature (generally 85°C), regardless of seasonal or daily hot water consumption.
The system is designed to heat the hot water to a temperature of 100 mL and store it. On the other hand, when actually using the stored hot water supply water, the temperature of the supply water that is mixed with it varies greatly depending on the season. The amount of hot water required for hot water supply generally varies greatly depending on the season, as the amount of hot water used increases and decreases in the summer. In other words, while the amount of heat stored in the water heater remains constant every day throughout the year, the amount of heat consumed varies depending on the season. The difference between the amount of heat stored in the hot water and the amount of heat consumed results in the water not being consumed within the day and remaining in the water heater as stored hot water for hot water supply, which is carried over to the next day unused. The heat radiation loss of this residual hot water storage hot water supply water is due to its relatively high temperature (85% if the amount used is small).
℃), which is extremely large, and the heat radiation loss appears as completely wasted power consumption.

As an electric water heater that solves the above problems,
The method described in JP-A-51-53645 is already known. This electric water heater is configured to detect the temperature of the supplied water, which varies greatly depending on the season, and when the water temperature is high, to control the power supply to the heating device to lower the temperature of the hot water stored in the hot water storage tank. This is what I did.

According to this electric water heater, it is possible to set the amount of stored hot water according to the season, and a considerable energy saving effect can be expected, but there is room for improvement in the following points.

In other words, if we closely observe the actual status of hot water usage in each household, we can see that the actual amount of hot water (heat consumption) consumed in each household not only differs depending on the season;
Daily usage conditions in each household, for example, changes in the number of people due to overnight stays or guests, presence or absence of bathing (in particular,
This varies greatly depending on whether or not you fill a large-capacity bathtub with hot water.

However, in the above conventional example, this point is not taken into consideration at all, and as long as the water temperature is constant, whether there is one person at home or the whole family is together, the number of people may increase due to visitors. Even if the amount has increased beyond that, the hot water will be stored at the same temperature, or even if it is known in advance that the bathtub will not be used, the hot water will be stored at the same temperature as on the day the bathtub is used. This resulted in high running costs.

The present invention was made as a result of intensive research in view of the above circumstances, and its purpose is to provide an electric water heater using nighttime electricity that can automatically set the appropriate amount of hot water storage according to the season and daily usage conditions. The aim is to provide the following products and to make running costs even lower.

In order to achieve the above object, the electric water heater using nighttime electricity according to the present invention includes an input operation section for inputting the number of users for the next day, an input operation section for inputting whether or not to use the bathtub, and other usage conditions. Calculates the total expected heat consumption from the number of users and whether or not the bathtub is used inputted by the input operation section, the memorized usage conditions, and the detected temperature of the water supply, and calculates the total expected heat consumption. Calculating the set temperature of hot water for hot water supply necessary for storing the amount of heat corresponding to the expected amount of heat to be consumed in the constant capacity hot water storage tank, and the temperature of the experimental hot water discharged from the hot water storage tank reaching the set temperature of the stored hot water for hot water supply that was calculated. The present invention is characterized in that it includes an arithmetic and control device configured to stop the heating action of the heating device when the heating occurs.

The above characteristic configuration provides the following significant energy saving effects.

That is, the present invention not only deals with changes in water supply temperature due to seasonal factors, but also changes in the amount of hot water used when the bathtub is used and when it is not used, as well as changes in the number of people using the hot water bath. ,for example,
If there is only one person at home due to a family trip or a sleepover, or conversely, if the whole family is present, or if there are more people than that due to guests, etc., the heating effect starts the day before. around 10:00 or 11:00 p.m., which is currently set by the power company.
By simply performing an extremely easy and simple operation of inputting the number of users and whether or not the bathtub will be used into the arithmetic and control device using the input operation section, the amount of stored hot water that matches the actual conditions of daily use can be set. No extra heating energy is used, and the amount of remaining hot water stored at the end of the day's hot water supply is minimized, reducing heat radiation loss and significantly reducing power consumption compared to conventional systems. be.

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

FIG. 1 schematically shows the overall structure of an electric water heater using nighttime electricity according to the present invention, and FIG. 2 shows its block diagram.

1 is the constant capacity V() (generally 370 in 3LDK,
It is an insulated hot water storage tank (460 is adopted in 4LDK), and there is a water supply pipe 2 at the bottom, and
A hot water supply pipe 3 is connected to the top thereof. The water supply pipe 2 is provided with a water supply valve 4, a pressure reducing check valve 5, and a pressure regulating valve 6 for automatically discharging the expanded amount to the outside of the hot water tank 1 when the hot water supply water in the hot water storage tank 1 is heated and expanded. Also, the water supply temperature T _p (℃) is provided between the water supply valve 4 and the pressure reducing check valve 5.
A water temperature measurement sensor 7 for measuring the water temperature in the hot water tank 1
It is installed in a position where it is not directly affected by the temperature of the water inside. A safety valve 8 is provided in the hot water supply pipe 3 near the hot water storage tank 1 to protect the hot water storage tank 1 from expansion and destruction when the pressure regulating valve 6 is not activated. 9
is a drain pipe, and 10 is a drain valve.

Reference numeral 11 denotes a heater as a heating device, which is connected to a late-night power source (AC200V) via a non-contact relay 12 and an earth leakage breaker 13, and starts heating when the late-night power is supplied (usually at 10 p.m.). It's about to start. Reference numeral 14 is a hot water temperature over-rise prevention device, which prevents the hot water temperature in the hot water storage tank 1 from reaching a dangerous value (for example, 90°C).
When this happens, the heating circuit of the heater is opened and the heating action is stopped regardless of the relay. 15 is the actual hot water temperature T′ _x in the hot water storage tank 1
This is a water temperature measurement sensor for measuring (℃). 16 is a corrosion protection electrode, and a printed circuit board 17
It is connected to a regular power source (AC100V) via an earth leakage breaker 18.

the water temperature measurement sensor 7, the non-contact relay 12,
The printed circuit board 17 is connected to an arithmetic and control unit 20 via a control cable 19.

In FIG. 1, the part surrounded by dotted line A is called the electric water heater main body, and the part surrounded by dotted line B is called an arithmetic control part, and these will be associated with the block diagram of FIG. 2, which will be described later.

The arithmetic and control unit 20 has a built-in microcomputer M (see FIG. 2) as described later, which calculates the following standard data, that is, the statistical standard amount of hot water used per person during bathing b( / person), statistical standard amount of hot water used per person in shower c (/
), the statistical standard amount of hot water used per household in the kitchen d(), the statistically standard amount of hot water used per household in the washroom e(), and the statistically standard amount of hot water used Tc(℃) in the memory in advance. I've let it happen.

The arithmetic and control device 20 also includes an input operation section 21 for inputting the number of people n and the bathtub capacity a() of the residence;
22 are provided. The latter, the bathtub capacity a, does not change, so if you set it at the time of installing an electric water heater in your house, there is no need to change it after that. However, if you know in advance that you will not take a bath the next day, It is sufficient to input the bathtub capacity a with zero. Since the number of people n varies from day to day, it is only necessary to enter it by around 10pm the night before depending on the number of people at home the next day.

Each of the above data, namely, hot water storage tank capacity V, bathtub capacity a, amount of hot water used per person when taking a bath b, amount of hot water used per person in the shower c, amount of hot water used per household in the kitchen d, washroom Amount of hot water used per household e, operating temperature Tc, detected temperature To of water supply, and number of people n
Based on this, the microcomputer M performs the following calculation.

First, the planned amount of hot water supply A based on the operating temperature Tc is calculated using the following formula: A=a+n(b+c)+d+e-. Note that this calculation has the same meaning as calculating the total expected heat consumption.
This calculation flowchart is shown in FIG. 3A.

Next, set water temperature for hot water supply (hot water temperature in hot water tank 1)
Tx (°C) is determined by the following formula: Tx=μ{(A-V)(Tc-To)/V+Tc}-. This formula is based on the relationship that hot water (A, Tc) is supplied by mixing the hot water supply water (Tx, V) in the hot water storage tank 1 and the water supply (A-V, To).
It is calculated assuming that the amount of heat V (Tx - Tc) lost by the hot water supply water in the hot water storage tank 1 is equal to the amount of heat given to the water supply (A - V) (Tc - To), and μ is the heat radiation loss due to hot water storage, It is a correction coefficient determined in consideration of variations in the amount used by users, or errors between the detected water supply temperature during calculation and the actual water supply temperature during hot water supply.It is a value close to 1, and is stored in advance. There is.

The set temperature Tx of the hot water supply water in the hot water storage tank 1 can be determined by the above calculation, but since this is just a calculation result, it may be an inappropriate value for hot water supply. Therefore, the upper and lower limits of this calculated value Tx are regulated by the appropriate maximum temperature Tmax and the appropriate minimum temperature Tmin (which are also stored in advance). A flowchart of this calculation is shown in FIG.

Thus, the set temperature of the hot water supply water in the hot water storage tank 1
Tx is finally determined.

Then, the arithmetic and control unit 20 compares the actual hot water temperature detected in the hot water tank 1 by the hot water temperature measurement sensor 15 with the actual hot water temperature T'x, and when Tx>T'x, the arithmetic and control unit 20 controls the heater 11 to perform a heating operation by a heating command. When Tx≦T'x, a heating stop command is sent to the non-contact switch 12 to cut off the heating operation, thereby stopping the heating action of the heater. An overall flowchart of the above calculations and control is shown in FIG.

In the above example, in order to explain the present invention in an easy-to-understand manner, a simple model was shown in which only the number of people and bathtub capacity were input as the usage conditions for the next day. , Amount of hot water supplied to the bathtub a(), 1 during bathing, shower, kitchen, washroom, and other hot water supply equipment
Amount of hot water used per person b, c, d', e'... (/person),
It may be configured so that the operating temperatures Ta, Tb, Tc, Td′, Te′, etc. at each location can be input arbitrarily on a daily basis, or the hot water usage may be different depending on adults, children, or different personalities. Since it is normal for there to be a considerable difference, simply setting the number of people may not be appropriate to the actual situation, so various design changes have been made to the above formula, such as configuring the calculation results to be able to perform premium correction or discount correction. This can be easily done by modifying the program based on this.

FIG. 5 shows the main part of the configuration of the arithmetic and control device 20 when the above-described modified configuration is adopted.

23 is a 3-position switch: AUTO/MANUAL/OFF;
When set to , the calculation control is performed by inputting only the number of people n using the condition input keyboard 24 as in the embodiment described later, and using the other data stored in the memory in advance.
When set to MANUAL, the data a,
b, c, d', e', Ta, Tb, Tc, Td', Te' and n
Any settings can be entered using all the condition input keyboards 24. At this time, the light emitting diodes in the input item indicating section 26 sequentially emit light from the left to indicate the input item, so it is only necessary to input the operating temperature, amount of hot water used, and number of people for that item. Incidentally, since the light emitting locations of the light emitting diodes can be shifted sequentially by pressing the data input key, it is only necessary to press the data input key if the data is not changed.
For areas that are not used, the amount of hot water used or the number of people may be entered as 0. The input value is digitally displayed on the display unit 25 each time, so even if you make a mistake in the input operation, you can clear it with the clear key and input the correct value again. Reference numeral 27 is a correction switch, which can be shifted to the + side when a slightly larger amount of hot water is desired, and to the - side when a slightly smaller amount of hot water is desired. When the changeover switch 23 is set to OFF, the set water temperature in the hot water tank 1 is set regardless of the data stored in the memory.
It is said to be 85℃.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the electric water heater using nighttime electricity according to the present invention, and FIG. 1 is a schematic diagram of the overall configuration;
FIG. 2 is an overall block diagram, FIG. 3 A and B are partial flowcharts, FIG. 4 is an overall flowchart, and FIG. 5 is an explanatory diagram of main parts of another embodiment. a... Bathtub capacity, n... Number of users, (b, c,
d, e, V, T _c , T _nio , T _nax , μ...)...Other usage conditions, To...Water supply detection temperature, Tx...Hot water storage water supply temperature, Tx'...Actual detected hot water temperature, 1 ... Hot water storage tank, 11 ... Heating device, 20 ... Arithmetic control device,
21, 22... Input operation section.

Claims (1)

[Claims] 1 An input operation section 21 for inputting the number of users n for the next day, an input operation section 22 for inputting whether or not a bathtub will be used, and other usage conditions b, c, d, e,
V, T _c , T _nio , T _nax , μ; and the detected water supply temperature T _p
From this, calculate the total expected heat consumption, and calculate the hot water storage hot water supply water set temperature _T
and the actual detected temperature in the hot water storage tank 1.
Electric hot water using nighttime electricity, characterized by comprising a calculation control device 20 configured to stop the heating action of the heating device 11 when T' _x reaches the calculated stored hot water supply water setting temperature T _x vessel.