JP2634624B2 - Hot water outlet temperature control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a hot water supply temperature control of a water heater in which a thermomixing valve is built in an appliance and a desired temperature and quantity of hot water are obtained by microcomputer control. It is about the method.

[Conventional technology]

A thermo-mixing valve is built in the appliance, and when the tap is opened, the water flow sensor detects the flowing water, and when the amount of flowing water is above the minimum operating flow rate of the appliance, it is ignited and the feed water is heated to a predetermined temperature by the heat exchanger. On the other hand, a water heater that compares the supply water temperature with the temperature of the hot water produced by the heat exchanger, mixes the water with the thermomixing valve, and controls the microcomputer control unit to output the water at the set temperature is the fourth type. It is configured as shown in the figure.

In FIG. 4, 1 is a burner, 2 is a heat exchanger, and 3 is a fan. Gas is supplied to the burner 1 through a solenoid valve 4 and a proportional valve 5 to a water supply pipe 8 leading to the heat exchanger 2. Is
A water amount sensor 6 and a water governor 7 of variable water temperature are provided. Further, a water supply pipe 8 upstream of the water quantity sensor 6
The hot water 9 is connected to the hot water 9 via a bypass 10 and a thermo mixing valve 11, the hot water temperature is detected by the thermistor 12, and the thermo mixing valve 11 is controlled by the microcomputer control unit 13 based on the hot water temperature and the supply water temperature. Then, hot water at a desired temperature is supplied from the hot-water tap 14. Numeral 15 is a thermistor for detecting the temperature of hot water, and 16 is a remote control for setting a desired hot water temperature and hot water supply amount.

The water heater as described above allows a constant temperature, for example, 60 ° C. hot water to be obtained under any water temperature conditions without squeezing the hot water tap 14. / min, the water temperature is controlled to about 12 / min when the water temperature is 25 ° C., and thus the hot water and the water heated to, for example, 60 ° C. by the heat exchanger 2 are mixed at the thermomixing valve 11 and set from the tap 14 to the remote control 16. It is configured to supply hot water at a predetermined temperature.

[Problems to be solved by the invention]

The capacity range of the water heater as described above is, for example, a minimum of 3.5 to 16 and the minimum flow rate that can maintain gas proportional control with the minimum number of appliances is fixed.
In the case of the hot water heater of No. 2, the appliance is not operated when there is no running water of 2.5 / min or more. When the hot water tap is opened, the flow rate sensor 6 detects the amount of water, It is configured to ignite only when it is at / min.

By the way, in this type of water heater, since the minimum operating flow rate of the appliance is specified as described above, the burner may be extinguished and become unusable depending on the use conditions even within the capability range of the appliance.

For example, consider the case where the water temperature is 15 ° C., the tap water (set) hot water temperature is 40 ° C., and the tap water amount is 4 / min. In this case, the number of hot water supply units is calculated by the following equation (40−15) × 4. ÷ 25 = 4 (No.), which is originally within the hot water supply capacity range.

However, when the hot water tap is opened, water flows into the appliance, and water flows through the thermo-mixing valve 11 (however, flows from the hot side of the thermo-mixing valve and the water side is closed), and the flow rate is 4 / min. Therefore, the water amount sensor 6 detects this and starts the ignition operation. However, the combustion is started and the water is heated by the heat exchanger 2, and the hot water temperature reaches a predetermined temperature of 60 ° C.
When the temperature approaches (constant temperature), the hot water side of the thermomixing valve 11 starts to be throttled as the hot water temperature rises, and at the same time the water side opens. Is the minimum operating flow 2.5
Automatic fire extinguishing below / min.

The flow rate (Q ₁ ) flowing through the heat exchanger is calculated by the following equation.

Q = (T−T ₀ ) ÷ (T ₁ −T ₀ ) × Q where T: mixed temperature of hot water and water (set temperature of remote control) T ₀ : water temperature T ₁ : hot water temperature generated by heat exchanger (constant temperature) ) Q: substituting the condition tapping amount above equation _{Q 1 = (40-15) ÷ (} 60-15) × 4 = 2.2 (/ min) , and the below 2.5 / min is the minimum operating flow rate of the instrument Fire is extinguished automatically.

In addition to the above conditions, fire may be extinguished when the water temperature is high or when the temperature of hot water produced by the heat exchanger is high.

The present invention solves the problems of the prior art as described above, and a method of controlling a water heater that can supply hot water at a set temperature under any use condition within the range of the hot water supply capability of the appliance. Is to be provided.

[Means for solving the problem]

In order to achieve the object as described above, the present invention detects a tapping amount Q when a hot water tap is opened by a water amount sensor,
Based on the detected value, the following equation (1) Q = (T−T ₀ ) ÷ (T ₁ −T ₀ ) × Q (1) where T, T ₀ , T ₁ , and Q are the same as above. performs computation, resulting Q _1, the temperature T ₁ of the hot water by comparing the minimum operating flow rate of the instrument is made of the heat exchanger to determine whether may maintain a minimum operating flow rate of the instrument as such, NO In the case of ( ₁₎ , the combustion condition of the appliance is changed so as to lower the temperature T1 of the hot water produced by the heat exchanger.

[Action]

(1) Temperature T ₁ of the hot water produced in the heat exchanger by comparing the minimum operating flow rate Q _1, the instrument obtained by performing the calculation of the equation can maintain minimum operating flow rate of the instrument at that untilゝJudgment as to whether or not, in the case of NO, the combustion conditions are changed so as to lower the temperature of the hot water produced by the heat exchanger to, for example, T ₁ = 50 ° C, or to the set temperature of the remote control. In any case, the flow rate through the heat exchanger will not be lower than the minimum operation flow rate of the appliance in any case, and the hot water supply capacity range can be secured without extinguishing even when a small amount of hot water is discharged.

〔Example〕

In the present invention, the use of the water heater shown in FIG. 4 is the same as the conventional one, but the judgment and control functions in the microcomputer control unit 31 are changed so that the temperature of the hot water produced in the heat exchanger is changed as in the conventional case. The switching control is not performed at one point.

FIG. 1 is a flowchart using the control method of the present invention.

As shown in this figure, when the hot water tap is opened, the amount of hot water Q is detected by the water amount sensor 6 before the appliance is burned, and based on the detected value, Q = (T−T ₀ ) ÷ (T ₁ −T ₀ ) × Q is calculated, and based on this, it is determined whether the minimum working flow rate of the appliance can be maintained until T ₁ = 60 ° C. Is controlled by the microcomputer control unit 13 so as to burn at T ₁ = 50 ° C. or the set temperature of the remote controller 16.

For example, when T ₁ = 60 ° C., since Q ₁ = 2.2 (/ min), it is determined that the minimum working flow rate of the appliance cannot be maintained (below the minimum working flow rate), and the combustion condition is set to, for example, T ₁ = 50 ° C.
Change a, Q ₁ = a (40-15) ÷ (60-15) × 4 = 2.9 (/ min) or T ₁ = 40 ° C. and then _{Q 1 = 4.0 (/ min)} . When T ₁ = 40 ° C., there is no mixing with water by the thermo mixing valve.

In addition, the above-described detection is of course at the start of combustion,
As shown in FIG. 1, when the flow rate (Q ₁ ) flowing through the heat exchanger is equal to or higher than the minimum operating flow rate of the equipment, the temperature of the hot water generated by the heat exchanger is always detected during the combustion of the equipment. Temperature T ₁
Switch to 60 ° C. That is, as shown in FIG. 2, basically, hot water of 60 ° C. is produced in the heat exchanger 2 and mixed with water by the thermomixing valve 11 to supply hot water. If the flow rate Q ₁ through the vessel 2 is likely below the minimum operating flow rate of the instrument, it is controlled to lower the temperature of the hot water produced in the heat exchanger as shown in FIG. 3 (detected by the thermistor 12).

〔The invention's effect〕

As described above, according to the present invention, the temperature of the hot water produced by the heat exchanger is not fixed at one point, and it is determined whether or not the hot water temperature can maintain the minimum operation flow rate of the appliance. In the case of NO, the combustion conditions are changed so as to lower the temperature of the hot water produced by the heat exchanger, so that even when a small amount of hot water is discharged, the hot water can be supplied within the hot water supply capacity range without extinguishing the fire.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a control method according to the present invention;
FIG. 2 is an explanatory diagram of a case where water is mixed by a thermo-mixing valve, and FIG. 3 is an explanatory diagram of a case where hot water of a set temperature is made by a heat exchanger and not mixed with water by a thermo-mixing valve. FIG. 4 is a diagram showing the overall configuration of the water heater. 1 ... burner, 2 ... heat exchanger, 3 ... fan, 4 ...
Solenoid valve, 5 ... Proportional valve, 6 ... Water amount sensor, 7 ... Water temperature variable water governor, 8 ... Water supply pipe, 9 ... Hot water pipe, 10 ...
… Bypass pipe, 11 …… Thermo mixing valve, 12,15
... thermistor, 13 ... microcomputer control unit, 14 ... tap, 16 ... remote control.

Claims (1)

(57) [Claims] 1. A thermo-mixing valve is built in an appliance, and when a tap is opened, flowing water is detected by a water amount sensor.
When the amount of flowing water is equal to or more than the minimum operating flow rate of the appliance, the appliance is ignited and the feed water is heated to a predetermined temperature by the heat exchanger,
On the other hand, in a water heater that compares the hot water temperature with the hot water temperature generated by the heat exchanger, mixes the water with a thermomixing valve, and controls the microcomputer control unit so that the hot water is discharged at a set temperature. the tapping amount Q when opening detected by water sensor, the following equation (1) Q = (T-T ₀₎ based on the detected value _{÷ (T 1 -T 0) ×} Q ...... (1) where T: Mixing temperature of hot water and water (set temperature of remote control) T ₀ : Water temperature T ₁ : Temperature of hot water produced by heat exchanger Q: Calculation of hot water output, obtained Q ₁ and minimum operating flow rate of equipment to determine whether the temperature T ₁ of the hot water produced in the heat exchanger by comparing may maintain a minimum operating flow rate of the instrument at that untilゝbets, temperature of the hot water produced in the heat exchanger in the case of NO tapping temperature control method of a water heater, characterized in that allowed to change the combustion conditions of the instrument to lower the T _1.