JPH0120608Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a device for preventing the load on an electric water heater that utilizes surplus electricity late at night from being concentrated immediately after switching between day and night.

Recently, with the spread of electric water heaters that utilize surplus electricity late at night, the time switches of electric water heaters in each household are turned on at the same time immediately after 11:00 p.m., when the late-night electricity period begins, so it takes a while from immediately after this. Peak electricity demand tends to continue during this period. 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 water in the water heater reaches the specified temperature will depend on the amount of remaining hot water. Since each one is different, the energization time is also different,
For example, according to actual measurements at an electric power company, the power supply time is about 2 to 3 hours in the summer and 5 to 6 hours in the winter. Due to this situation, the late-night power period is 8 hours from 11:00 pm to 7:00 am, but the demand for electricity peaks from 11:00 pm to 3:00 am at the beginning of the period, and on the contrary, the demand for electricity peaks in the early morning hours. Electricity demand decreases between 4:00 a.m. and 7:00 a.m., and a decrease in power generation efficiency and power transmission efficiency becomes a problem at this point.

As a solution to this problem, there is a conventional method of extending the energization time of an electric water heater, as shown in FIG. In the figure, reference numeral 1 denotes a tank of an electric water heater, which is made of steel and whose inner surface is lined with enamel. A sheathed pipe heater 2 is provided at the bottom of the tank 1, and is divided into two heaters 2A and 2B each having a capacity of 1/2. The capacity of these heaters is, for example, 2.2KW each.
It is. Two upper and lower thermostats 3A and 3B are attached to the outer wall of the tank 1, and these thermostats sense the temperature of the water in the upper and lower parts of the tank, respectively, and each is a contact that opens and closes depending on the temperature of the water. These thermostats A and 3B are connected to heaters 2A and 2B, respectively.
connected to.

The connections of these elements are as shown in FIG. That is, the 2A-3A series circuit and the 2B-3B series circuit are connected in parallel to each other and connected to an AC 200V power source. With this method, if the tank is filled with water, both thermostats 3A and 3B are closed, but if there is water remaining at the top of the tank, thermostats 3B and 3B are closed.
only is closed and 3A is open. Therefore, in the former case, both heaters 2A and 2B are energized, but in the latter case, only heater 2B is energized.
In this latter case, when the 200V AC power is turned on, heating starts immediately at 1/2 capacity of heater 2B, and this heating warms the water in the lower part of the tank, causing convection inside the tank. The temperature of the hot water at the top also gradually decreases. When this temperature falls to a predetermined value, the thermostat 3A is also closed, and accordingly the heater 2A also starts to be energized, at which point the entire capacity of the heater is energized. Since it takes quite a long time to energize the entire capacity, the energization of 1/2 capacity of the heater 2 is extended by this time. Further, since the delay in the energization time differs depending on the amount of hot water remaining in the tank, the delayed full capacity energization tends to be slightly dispersed as a whole. Conventional electric water heaters have a thermostat installed only at the bottom of the tank, so even if the heater has two elements, the entire capacity is energized at once, so the energization time is short, but it requires a large amount of power consumption in a short period of time. , a large amount of electricity consumption by each household will be concentrated at one time. In contrast, in the conventional improved method described above, the energization time is extended by about twice, so power concentration is considerably alleviated.

In addition to the above-mentioned improvement method, conventional control circuits have been used that detect the amount of hot water remaining inside the tank by pasting several thermistors as temperature sensing elements on the tank surface, and house a timer mechanism that delays the energization time accordingly. There are ways to prepare.

However, in each of the above conventional systems, a thermostat or thermistor is attached to the electric water heater when it is manufactured in a factory. This method would be effective if adopted at a time when the number of new electric water heaters is increasing rapidly, but recently the penetration rate of electric water heaters has plateaued at around 15%. As mentioned above, the conventional method that requires modification of existing electric water heaters is difficult to modify in practice, so applying it only to newly adopted electric water heaters will not have practical effects. few.

In order to solve the above problems, the present invention provides a temperature sensor that has a simple structure and can be easily installed in existing electric water heaters. The drawings will be explained in detail below. In FIG. 3 showing one embodiment of the present invention, the base body 7 of the temperature sensor is a channel-shaped rod-shaped material, and the material is heat resistant due to the purpose of use, and it is made of FRP or other suitable material such as a fishing rod. It is made of a resin such as nylon that is highly elastic enough to withstand bow-like bending. Moreover, the reason why this rod is formed into a channel shape, that is, a shape having an upright portion at the end edge, is to make it easier to return to the original straight shape when returning from bending. A plurality of permanent magnets 6 are attached to the surface of the base body 7 at the tip and at positions spaced from each other at appropriate intervals in the longitudinal direction of the rod.
For this attachment, for example, epoxy resin is used to adhere to the substrate surface. An appropriate number of thermistors 5, for example four, are also attached to the surface of the base 7 at appropriate intervals in the longitudinal direction of the rod, and these are also fixed to the surface of the base in the same manner as described above. These thermistors 5 are connected to each other in series with a lead wire 8.
is derived to the outside.

Installation work on site will be carried out as shown in Figure 4. In the figure, the tank 1 is the outer case 4.
glass wool 9, which is a heat insulating material, is filled in between. A box 10 is attached to the lower front of the case 4, and this is a conventional box that covers the front of the part where the heater 2, thermostat, etc. are attached. The sensor base 7 is inserted into the tank 1 from the opening of the box 10.
It is inserted toward the top of the outer surface. At this time, since the base body 7 has sufficient elasticity, it can be appropriately bent into an arch shape and inserted easily. Further, a permanent magnet 6 is attached to the tip of the base 7, and this is attracted by the steel tank 1, so that the tip first comes into close contact with the tank surface, and then as the insertion of the base 7 progresses, the tip becomes smaller. Since the lower permanent magnet 6 is successively attracted to the side wall of the tank, the base body 7 finally elastically returns to its original straight state and its bottom surface is brought into close contact with the surface of the tank as a whole. Incidentally, since the glass wool 9 between the tank 1 and the case 4 is cotton-like and relatively fluffy, it does not pose a significant obstacle when inserting the base body 7.

The completed electric water heater after installing the temperature sensor is shown in Figure 5. In the figure, a control box 13 is attached to the upper surface of the outer case 4, into which a lead wire 14 for input power is introduced, and a lead for supplying power to the heater 2 between it and a box 10 on the lower surface of the case. A wire 15 and a thin lead wire 8 of the thermistor 5 are provided. The control device in the control box 13 takes advantage of the fact that the total resistance value of the thermistor 5 changes depending on the amount of hot water remaining in the tank, and appropriately sets the time to start energizing the heater 2 according to the total resistance value. It has a delaying effect. If a control device that uses a temperature sensor to extend the time when electricity is turned on to the heater is applied to more than half of all existing electric water heaters, it will be possible to extend the time when power is turned on to the heater during the hours of 4:00 a.m. to 7:00 a.m., when electricity demand traditionally drops significantly. It becomes possible to shift the previous demand, thus greatly improving power generation efficiency and power transmission efficiency. Note that a hot water sampling pipe 11 from the top surface of the tank passes through the center of the upper surface of the case 4, and a water supply pipe 12 to the tank passes through the lower surface.

According to the present invention, it is possible to easily attach multiple temperature sensing elements to an existing electric water heater along the vertical direction of the surface of the water heater tank, making the effective use of late-night electricity by the electric water heater even more efficient. There is an effect that can be made good.

[Brief explanation of the drawing]

Fig. 1 is a side view of a conventional improved electric water heater, Fig. 2 is its electrical connection diagram, Fig. 3 is a perspective view of the temperature sensor according to the present invention, Fig. 4 is a side view showing the installation process; Figure 5 is a perspective view of the entire completed electric water heater. 1: Water heater tank, 2: Heater, 3A, 3
B: Thermostat, 4: Exterior case, 5: Thermistor, 6: Permanent magnet, 7: Rod-shaped base, 8: Lead wire, 9: Glass wool.

Claims (1)

[Scope of utility model registration request] In order to attach it closely to the side wall of the tank of an existing electric water heater, a rod-shaped base made of a heat-resistant resin with high elasticity that can be bent into an arched shape is attached to the surface of the rod-shaped base. A temperature sensor for electric water heaters consisting of multiple temperature sensing elements attached at intervals.