JPH02275249A - Control device of terminal electric hot water heater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a control device for a terminal water heater that is capable of immediately supplying hot water from a mixer faucet in a central hot water system widely used for home and commercial purposes. It is something.

BACKGROUND OF THE INVENTION Conventionally, central hot water systems have been widely used in which a gas instantaneous hot water heater is used as a heat source to obtain mixed water at an appropriate temperature from a mixer faucet in kitchens, baths, washrooms, etc. However, when the piping distance between these heat source devices and the terminal mixer tap becomes long,
The drawback was that cold water continued to flow out for a while even after the mixing faucet was opened, making it difficult to use. To prevent this, a system has been used in which a small-capacity terminal electric water heater of a hot water storage type is connected in series in a part of the piping as close as possible to the hot water mixing faucet.

An example of a conventional terminal electric water heater will be described below with reference to the drawings. In Fig. 3, 1 is a gas instantaneous water heater which is a heat source device, 2 is a hot water storage type terminal electric water heater (hot water storage capacity is about 2 liters), 3 is a thermostatic type hot water mixing faucet, 4 is hot water side piping, 5 is the water side piping.

The operation of the terminal electric water heater configured as described above will be described below.

First, when you set the hot water mixer tap to the appropriate temperature and open it, the hot water side 3a
From the terminal electric water heater 2, high temperature water heated to a predetermined temperature flows in, while from the water side 3b, cold water flows in.
The water in the water heater 2 is automatically mixed in an appropriate ratio using a thermostatic mixing faucet, and when the temperature reaches the appropriate temperature, the water in the electric water heater 2 is turned off when the water reaches a predetermined temperature. The water temperature is controlled, and the water from the mixing faucet is kept warm when it is not being used. Also, 3
When hot water flows into a, the burner 1a of the gas instantaneous water heater 1
The heated water passes through the pipe 4 and flows into the terminal electric water heater 2. At this time, the cold water stored in pipe 4 enters 2, but it does not mix with the pre-stored high-temperature hot water or the high-temperature hot water supplied from 1 before flowing out to 3a, so it flows out from 3C. You will always have hot water at the right temperature.

Problems to be Solved by the Invention However, in such a configuration, when the temperature of the water supplied from the water side piping is high, for example, in the summer, the temperature is 30°
It may become C. Therefore, if the set temperature of the hot and cold water mixing faucet is set to 40°C and the flow rate of the mixed water discharged from the hot and cold water mixing faucet is set to 5 lindres, the amount of water flowing through the burner 1c is small and the minimum ignition flow rate (commercially available products are usually per minute). 2 liters), the burner 1b does not ignite.At this time, cold water is continuously supplied to the terminal electric water heater 2, so the water flowing into the terminal 3a becomes cold in a short time, and the burner 1b does not ignite. The problem was that only cold water could be obtained. These tendencies are noticeable when the flow rate of the mixing faucet is set low or when the water temperature on the water side is high.

The present invention solves the above problems and provides a control device for a terminal electric water heater that ensures a flow rate higher than the minimum ignition flow rate of a gas instantaneous water heater.

Means for Solving the Problems In order to solve the above problems, the terminal electric water heater control device of the present invention provides a control device for controlling water temperature in a water heating system including a gas instantaneous water heater, a terminal electric water heater, and a hot water mixing faucet. A detection device, a flow rate setting device that can preset the minimum required flow rate on the hot water side, and boiling based on the supply water temperature obtained by the water temperature detection device and the preset flow rate setting value. 1, a boiling water temperature calculation device that calculates the temperature, and a heater control device that controls the heater based on the boiling water temperature.

Effect: The terminal electric water heater control device of the present invention has the above-mentioned configuration and can adjust the boiling water temperature while detecting the water temperature of the water side piping, so when the water temperature is high, the water temperature can be set low. . Therefore, even when the water temperature is high, it is possible to secure a flow rate that is higher than the minimum ignition flow rate of a gas instantaneous water heater, and the mixer tap continuously supplies mixed water at a stable temperature, making it an easy-to-use hot water supply system. can be provided.

Embodiment Hereinafter, a control device for a terminal electric water heater according to an embodiment of the present invention will be explained based on the drawings.

In Figures 1 and 2, 1 is a gas instantaneous water heater which is a heat source, 2 is a terminal electric water heater (hot water storage capacity is about 2 liters),
3 is a thermostatic hot water mixing faucet, 4 is hot water side piping, 5
is the water side piping, 6 is the water temperature detection device, 7 is the flow rate setting device, 8
1 is a boiling water temperature calculation device, 9 is a heater control device, 10 is a terminal electric water heater control device, and 11 is a heater.

The operation of the terminal electric water heater control device configured as described above will be described below.

First, in FIG. 2, a water temperature detection device 6 is attached to the water side piping to detect the water temperature, while the minimum required flow rate of the gas instantaneous water heater can be set in advance by a flow rate setting device 7. ° In this case, the minimum flow rate can be set to 2 liters by the user. If the water temperature Tc and the minimum flow rate iQh are known, the boiling water temperature of the electric water heater, that is, the hot water temperature at the initial stage of hot water dispensing, can be determined by the following equation.

Qh Here, Qh...Flow rate on hot water side, Qc...Flow rate on water side Qm...Flow rate of mixed water, Th...
Hot water side temperature Tc...Water side temperature, Tm...
...Temperature of mixed water In this relationship, if the minimum required flow IQm and hot water temperature Tm from the mixing faucet are stored in advance, Th becomes a function only of Tc and can be easily calculated. In this way, based on the boiling water temperature value obtained by the boiling water temperature calculation device 8, the water in the water storage device is heated to a predetermined water temperature by the heater control device 9. The control process is summarized as shown in the block diagram in Figure 2. In this way, the terminal water heater boils water according to the water temperature, so even in the summer when the water temperature is high, the flow rate is over 2 liters per minute, and the burner There is no problem of igniting, and hot water can be used without interruption even if the mixing faucet is opened and used continuously.

Effects of the Invention As is clear from the above description of the embodiments, the control device for a terminal electric water heater of the present invention is capable of predetermining the required flow rate of water supply for a terminal electric water heater equipped with a gas instantaneous water heater, a terminal electric water heater, and a hot water mixing faucet. a flow rate setting device that can be set; a boiling water temperature calculation device that calculates a boiling water temperature based on the water supply temperature obtained by the water temperature detection device and a preset flow rate setting value; Since it is equipped with a heater control device that controls the heater based on the heater, even when the water temperature is high like in summer, it is possible to secure a flow rate that is higher than the minimum ignition flow rate of a gas instantaneous water heater, and it is possible to The system continuously supplies mixed water at a stable temperature, providing an easy-to-use hot water supply system.

Also, lowering the boiling water temperature when the water temperature is high, such as in the summer, is energy efficient and economical.

[Brief explanation of drawings]

Fig. 1 is a system diagram of a hot water supply system showing an embodiment of the present invention, Fig. 2 is a block diagram illustrating a control method of a terminal electric water heater control device of the present invention, and Fig. 3 is a system diagram of a conventional hot water supply system. FIG. 1...Gas instant water heater, 2...Terminal electric water heater, 3...Hot water mixing faucet, 4...
Hot water side piping, 5...Water side piping, 6...Water temperature detection device, 7...Flow rate calculation device, 8...
. . . Boiling water temperature calculation device, 9 . . . Heater control device, 10 . . . Terminal electric water heater control device.

Claims (1)

[Claims] In a hot water system equipped with a gas instantaneous water heater, a terminal electric water heater, and a hot water mixing faucet, a water temperature detection device, a flow rate setting device that can preset the minimum required flow rate on the hot water side, and a water temperature detection device that can be used to The boiling water temperature calculation device calculates the boiling water temperature based on the supplied water temperature and the preset flow rate setting value, and the heater control device controls the heater based on the boiling water temperature. Control device for terminal electric water heater.