JP2003139393A - Control method for hot-water supply temperature and solar water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar water heater with an auxiliary heat source built therein contributing to energy saving by effectively using high-temperature hot water reserved using solar heat. SOLUTION: A rise of heating temperature (α) by the auxiliary heat source 11 is calculated with an equation including (H×25)÷Q, and when a hot-water temperature entering the auxiliary heat source 11 is controlled on the side of a solar-heat water supplier 1, calculation is made with a mixed hot-water flow value (L/minute) as an initial value for Q at the start of hot-water supply (at restart when restarted after stop of hot-water supply), and then, the hot-water supply temperature is controlled by updating to the latest minimum mixed hot-water flow value (L/minute). Here, H is the number of a heating capacity lower limit value of the auxiliary heat source 11 and Q for the mixed hot-water flow (L/minute).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar water heater with a built-in auxiliary heat source in which an auxiliary heat source device is connected to a solar water heater (main body), or a method for controlling the hot water temperature.

[0002]

2. Description of the Related Art An auxiliary heat source built-in type solar water heater in which a solar water heater and an auxiliary heat source device (gas or oil instant water heater, etc.) are connected in series has been known. by the way,
A general-purpose gas instantaneous water heater has a lower limit in heating capacity and cannot adjust the temperature within a predetermined range. For example, in the case of a general gas instantaneous water heater, the lower limit of heating capacity is about 3 (1 is the capacity to heat 1 liter of water at 25 ° C per minute), which is 10 liters of water per minute. It has a heating capacity that can raise the temperature of about 7.5 ° C. Therefore, the hot water temperature from the solar water heater is the desired hot water supply temperature (or set temperature;
When the temperature is lower than (TR), the temperature of the hot water greatly exceeds that temperature.

When a solar water heater and an auxiliary heat source device such as a gas (or oil) instant water heater are combined to supply hot water of a desired temperature by a control system, first, in order to avoid the overheating, the inside of the solar water heater At this time, the hot water that boiled by exchanging heat with the solar heat (stored in the hot water storage tank) was once diluted with water supplied from a separate pipe to a temperature lower than the desired temperature (about 30 ° C). The conventional method is to supply the auxiliary heat source device to the auxiliary heat source device, and then heat and supply to the desired temperature set by the control unit.

[0004]

However, even when the water temperature from the solar water heater to the auxiliary heat source device is set to about 30 ° C., T
Under conditions where R is low and the amount of water is small, the temperature of the hot water heated by the auxiliary heat source device may greatly exceed TR. For example, if TR is 37 ° C., the amount of water is 5 liters / minute, and the minimum heating capacity of the auxiliary heat source device is No. 3, the temperature rise is 3 × 25/5 liters / minute = 15 ° C. The hot water outlet temperature from the water heater is 45 ° C (= 30 + 15), which greatly exceeds the desired hot water supply temperature (TR) of 37 ° C. If you lower the water temperature from the solar water heater to the auxiliary heat source,
The heating energy (that is, the amount of fuel used) in the auxiliary heat source increases, which is a waste of energy. The present invention solves such a problem, that is, effectively uses high-temperature hot water stored by utilizing solar heat, and therefore provides an auxiliary heat source device-incorporated solar water heater that contributes to energy saving. is there.

[0005]

In order to achieve the above object, the present invention has the following constitution. That is, in the present invention, in the method for controlling the hot water supply temperature of the solar water heater 30 including the solar water heater 1 and the auxiliary heat source device 11, the combustion / heating temperature increase by the auxiliary heat source device 11 is (H × 25).
÷ Q (however, H is the number of the heating capacity lower limit of the auxiliary heat source device 11, and Q is the mixed hot water flow rate (L / min)) is calculated by an equation including the solar water heater 1 to the auxiliary heat source device. When controlling the temperature of hot water to enter 11, the Q is the mixed hot water flow rate value (L / min) at that time at the start of hot water supply (when restarting after stopping hot water supply), and then the most recent The method for controlling the hot water supply temperature is characterized by using the minimum mixed hot water flow rate value (L / min).

Here, "hot water supply" means a solar water heater 30.
It means that the hot water is discharged from the hot water outlet 21 (normally to a desired temperature). Further, "the latest minimum value of the mixed hot water flow rate" means the flow rate value (flow velocity) measured by the flow meter 24 at every moment.
When the flow rate becomes smaller than the flow rate immediately before, it means the reduced flow rate value, and when the flow rate value from moment to moment becomes larger than the flow rate immediately before, it means the stored flow rate value as it is. To do.

The present invention also relates to a solar water heater 30 comprising a solar water heater 1 and an auxiliary heat source device 11 connected to the outlet side thereof. That is, the solar water heater 1 includes a hot water storage tank 4 that stores hot water heated by solar heat, a thermometer 23 that measures the hot water temperature (Th) of the hot water storage tank 4, and hot water from the hot water storage tank 4. Branch pipe 22
A hot water mixing device 5 for mixing the feed water from the above, a flow meter 24 for measuring the mixed hot water amount (Q) after mixing, a thermometer 23 for measuring the hot water temperature after mixing, and a first controller 6. The auxiliary heat source device 11 includes a heat exchanger 13 including a pipe, a combustion / heating unit 12, and a water flow detector 16 disposed upstream of the heat exchanger.
And a thermometer 17 disposed downstream of the heat exchanger, and a second control unit 14, and when the Th is lower than the desired hot water supply temperature (TR), the combustion / heating unit 12 on the auxiliary heat source side. On the solar water heater side, the outlet hot water temperature (from the solar water heater) is controlled by adjusting the hot water mixing device 5 with TR as the control temperature on the solar water heater side, and when the Th is less than TR, the auxiliary On the heat source side, the combustion / heating unit 12 is operated, and on the solar water heater side, the outlet hot water temperature is controlled by adjusting the hot water mixing device 5 with TR- (H × 25) ÷ Q as the control temperature, and as the Q. Is the mixed hot water flow rate value (L /
Minute) is stored as an initial value, and when restarting after the hot water supply is stopped, the mixed hot water flow rate value (L / min) at the time of restart is stored as an initial value, and then the latest minimum mixed hot water flow rate value (L The solar water heater 30 has a structure for storing / minute) as an update.

Here, "the temperature of the outlet hot water is controlled by adjusting the hot water mixing device 5 with TR as a control temperature" means
This means adjusting the outlet hot water temperature of the solar water heater to TR (when Th is equal to or higher than TR) by diluting the hot water mixing device 5 with water via the first control unit 6. In addition, “TR- (H ×
25) ÷ Q, the outlet hot water temperature is controlled by adjusting the hot and cold water mixing device 5 "(when Th is less than TR), the water is mixed by the hot and cold water mixing device via the first control unit 6. The temperature of the outlet hot water of the solar water heater is TR- (H × 25) ÷
It means adjusting to Q.

As the auxiliary heat source, a gas instantaneous water heater, a petroleum instantaneous water heater, etc. can be used, preferably a gas instantaneous water heater, and more preferably a gas proportional combustion control type gas instantaneous water heater. Depending on the desired hot water supply temperature (set temperature; TR) and changes in the amount of hot water used, the gas amount is adjusted appropriately by feedforward control or feedback control,
This is because the hot water temperature at the outlet can be kept constant.

[0010]

Operation: When the hot water temperature (Th) of the hot water storage tank 4 is lower than the desired hot water supply temperature (TR), the combustion / heating unit 12 on the auxiliary heat source side
On the condition of running the
The hot-water mixing device 5 is adjusted with − (H × 25) ÷ Q as the control temperature. At this time, the mixed hot water flow rate Q is not set to a constant value, but an optimum flow rate value that matches the most recent hot water flow rate is selected, so the hot water supply temperature from the solar water heater 30 is the desired temperature (set temperature; TR). It is stable and stable.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the solar water heater or the hot water temperature control method of the present invention, the combustion / heating temperature increase amount by the auxiliary heat source device 11 is calculated by an equation including (H × 25) ÷ Q to calculate the solar hot water. When controlling the temperature of the hot water entering the auxiliary heat source device 11 from the water heater 1, as described above, the mixed hot water flow rate Q is not set to a constant value, but at the start of hot water supply (when restarting after the hot water supply is stopped, restart the hot water supply). At the time), the mixed hot water flow rate value (L / min) at that time is set as an initial value, and then the latest minimum mixed hot water flow rate value (L / min) is stored as an update and the above calculation is performed.
Hereinafter, the present invention will be described more specifically with reference to the accompanying drawings. FIG. 1 is a configuration diagram of an example of a solar water heater (with built-in auxiliary heat source device) according to the present invention, in which a gas instantaneous water heater is used as an auxiliary heat source device. Heat collector 10 installed on the roof, etc.
The water (or the antifreeze liquid) heated in 2 is forcibly circulated in the closed circulation path by the forced circulation pump 3, and the heat exchanger 2 in the hot water storage tank 4
The heat in the hot water storage tank 4 is indirectly heated by the heat exchange.
The hot water temperature of the hot water storage tank 4 is measured by the thermometer 23. The hot water discharged from the hot water storage tank 4 is appropriately diluted with the water from the branch pipe 22 by diluting and mixing (that is, adjusting the opening degree of the mixing valve of the hot water mixing device) by the hot water mixing device 5 via the first controller 6. After being mixed, it is supplied from the mixed hot water outlet 8 to the auxiliary heat source device 11.

On the side of the auxiliary heat source 11, the supplied hot water enters through the hot water inlet 20, passes through the heat exchanger 13 of the auxiliary heat source, and exits through the hot water outlet 21. Although not shown, the hot water outlet 21
Is divided into bathtub filling, hot water supply to the bathroom shower, hot water supply to the kitchen, hot water supply to the washroom, etc. (branch end pipe line), and the desired temperature of the user may differ for each hot water supply.

The control section of the solar water heater 30 will be described below.
The remote control 15 for setting the hot water temperature is remote control code 1.
8 is connected to the second control unit 14, and the second control unit 14 is connected to the first control unit 6 on the solar water heater side via the remote control cord 19. The desired hot water supply temperature (set temperature; TR) set by the remote controller 15 is controlled not only by the second control unit 14 on the auxiliary heat source device side but also by the first control unit on the solar water heater side via the second control unit 14. It is also transmitted to the section 6. This allows the user to recognize the hot water supply temperature desired by the user (that is, the set temperature: TR) on the solar water heater side. The data communication from the remote controller 15 to the first control unit 6 via the second control unit 14 may be performed by connecting the cords on the same communication line and directly receiving the data.

The method for controlling the hot water temperature in the solar water heater (with built-in auxiliary heat source device) according to the present invention, particularly the method for controlling the hot water temperature on the solar water heater side, is the hot water temperature (Th) of the hot water storage tank.
Is distinguished by the case where is equal to or more than TR and the case where is less than TR. FIG. 2 shows a flowchart of temperature control on the solar water heater side of the solar water heater (with built-in auxiliary heat source device) according to the present invention.

On the solar water heater side, when the hot water temperature (Th) of the hot water storage tank is equal to or higher than the desired hot water supply temperature (TR), the hot water mixing device 5 of the solar water heater 1 dilutes the water so that the outlet hot water temperature becomes TR. , To the auxiliary heat source side. This means that hot water is supplied as it is. Hot water temperature of hot water storage tank (T
When h) is less than the desired hot water supply temperature (TR), on the solar water heater side, the hot water temperature (Th) of the hot water storage tank is set to T by considering the combustion / heating temperature increase (α) due to the operation of the auxiliary heat source device 11.
It is lowered to R-α and then supplied to the auxiliary heat source side. Here, α is a value calculated by (H × 25) ÷ Q. Q
Is measured by a flow meter provided downstream of the hot water mixing device 5.

A concrete example will be further described. For example, when the hot water temperature (Th) of the hot water storage tank 4 is 40 ° C., the desired hot water supply temperature (set temperature; TR) is 42 ° C., H is No. 3, Q is 5 liters per minute, and α is (3 × 25). ÷ 5 = 15, and the control temperature in the hot and cold water mixing device 5 is 42−15 = 27 ° C. The hot and cold water mixing device 5 mixes the hot and cold water so that the temperature on the outlet side of the hot and cold water mixing device 5 becomes 27 ° C., and the resulting hot water of 27 ° C. is supplied to the auxiliary heat source side. Then, hot water can be supplied at the desired hot water temperature of 42 ° C. Thus, on the side of the auxiliary heat source, it is sufficient to heat the incoming hot water temperature (27 ° C.) to the set temperature TR with the minimum amount of heat, that is, the minimum capacity number. However,
As in the above example, when the hot water temperature of the hot water storage tank is between TR and TR-α, the hot water temperature of the hot water storage tank is once lowered and then heated by the auxiliary heat source device, so that amount of energy is wasted. Becomes

If the tank hot water temperature does not reach 27 ° C. (that is, TR-α), the hot water in the hot water storage tank is supplied to the auxiliary heat source device 11 as it is without being diluted with water.

The minimum capacity number of the auxiliary heat source device also varies depending on the device. Therefore, set H to be large and perform the calculation, or use the calculation formula of α as (H × 25) ÷
The temperature of the mixed hot water may be controlled to be somewhat lower by setting Q + K (a positive number). If K in the equation is, for example, 2 ° C., α
Is (3 × 25) ÷ 5 + 2 = 17 ° C., and the control temperature in the hot and cold water mixing device 5 is 42−17 = 25 ° C.

The thermometer 17 on the auxiliary heat source side is the heat exchanger 1
It is not impossible to dispose it on the upstream side of the heat exchanger 13 instead of on the downstream side of 3, and control the hot water supply temperature from the detected temperature.
However, it is preferably downstream of the heat exchanger 13 in terms of simplicity of the structure of the apparatus and cost.

Further, when the temperature entering the auxiliary heat source device changes, the phenomenon that the hot water supply temperature becomes unstable (out of the desired hot water supply temperature) occurs. For example, when the inlet temperature changes from 25 ° C. to 35 ° C., the solar water heater shown in FIG.
Since the inlet temperature is not directly detected, the hot water supply temperature may rise by a temperature close to the difference (= 35-25). However, this is usually temporary.

FIG. 3 shows a flow chart of the mixed hot water flow rate (Q) control of the hot and cold water mixing apparatus 5 in the control method of the present invention. This control normally works when Th is less than TR and the combustion / heating unit 12 is operating on the auxiliary heat source side. When hot water supply is started, the mixed hot water flow rate (measured value of the flow meter 24) at the start is first stored as an initial value,
Using the Q value, (H × 25) ÷ Q is calculated. The flow meter 24 measures the flow rate of the mixed hot water at that time moment by moment, and the first control unit 6 compares it with the previously stored Q value. If the Q value is larger than the previously stored Q value, the Q value is not updated, and if the Q value is smaller, the decreased flow rate of the mixed hot water is re-stored (updated). When the water flow detection device 16 does not detect a water flow equal to or greater than a predetermined value (or threshold value), it is determined that the water flow has stopped, and hot water supply is terminated. The water flow detection device 16 has a function of a safety valve that prevents overheated hot water supply.

[0022]

According to the hot water supply temperature control method or the solar water heater of the present invention, the following effects can be obtained. (1) When the hot water temperature of the hot water storage tank is equal to or higher than the desired hot water supply temperature (TR), the auxiliary heat source device is not operated and only the hot water of the hot water storage tank is diluted with water, so that no further energy is required. Contribute to energy saving. (2) When the temperature of the hot water in the hot water storage tank is lower than the desired hot water supply temperature (TR), the auxiliary heat source is heated on the condition that the auxiliary heat source is operating. At that time, the combustion / heating temperature increase (α) is calculated. In doing so, since the optimum flow rate value is selected for the mixed hot water flow rate Q according to the latest hot water flow rate, the hot water supplied from the solar water heater does not deviate from the desired temperature (set temperature; TR) and is stabilized. .

[Brief description of drawings]

FIG. 1 is a configuration diagram of an example of a solar water heater with a built-in auxiliary heat source device of the present invention.

FIG. 2 is a flowchart of temperature control on the solar water heater side in the control method of the present invention.

FIG. 3 is a flow chart of mixed hot water flow rate (Q) control of the hot and cold water mixing apparatus in the control method of the present invention.

[Explanation of symbols]

1: Solar Water Heater 2: Heat Exchanger 3: Forced Circulation Pump 4: Hot Water Storage Tank 5: Hot Water Mixing Device 6: First Controller 8: Mixed Hot Water Outlet 9: Water Inlet 10: Heat Collector 11: Auxiliary Heat Source Device 12: Combustion / heating unit 13: Heat exchanger 14: Second control unit 15: Remote controller 16: Water flow detector 17: Thermometer 18: Remote control code 19: Remote control code 20: Hot water inlet 21: Hot water outlet 22: Branch pipe 23: Thermometer 24: Flowmeter 30: (Auxiliary heat source device built-in type) Solar water heater

Claims (2)

[Claims] 1. A method for controlling a hot water supply temperature of a solar water heater comprising a solar water heater and an auxiliary heat source device, wherein a combustion / heating temperature increase amount by the auxiliary heat source device is (H × 25) ÷ Q.
(However, H is the number of the heating capacity lower limit of the auxiliary heat source device, and Q is the mixed hot water flow rate (L / min).)
When controlling the temperature of hot water entering from the solar water heater to the auxiliary heat source device, the Q is the mixed hot water flow rate value (L / min) at the start of hot water supply, and when restarting after stopping hot water, at the time of restart. A method for controlling the hot water supply temperature, which uses the mixed hot water flow rate value (L / min), and then uses the latest mixed hot water flow rate value. 2. A solar water heater comprising a solar water heater and an auxiliary heat source device connected to an outlet side thereof, wherein the solar water heater is a hot water storage tank for storing hot water heated by solar heat, and the hot water storage tank. A thermometer that measures the hot water temperature (Th) of the tank, a hot and cold water mixing device that mixes the hot water from the hot water storage tank and the feed water from the branch pipe, and a flow meter that measures the mixed hot water amount (Q) after mixing, It comprises a thermometer for measuring the temperature of the hot water afterwards, and a first control part, wherein the auxiliary heat source device is a heat exchanger including a pipe, a combustion / heating part, and a water flow arranged upstream of the heat exchanger. A detector, a thermometer disposed downstream of the heat exchanger, and a second controller are provided. When Th is equal to or higher than the desired hot water supply temperature (TR), the combustion / heating unit on the auxiliary heat source side is provided. On the condition that the solar water heater is stopped, TR is set to the control temperature on the side of the solar water heater, and the temperature is adjusted by adjusting the hot water mixing device When the outlet hot water temperature is controlled and the Th is less than TR, it is necessary to operate the combustion / heating unit on the auxiliary heat source side, and TR- (H × 25) ÷ Q on the solar water heater side. As the control temperature, the outlet hot water temperature is controlled by adjusting the hot and cold water mixing device 5, and as the Q, the hot water supply flow rate value (L / min) at that time is stored as an initial value and restarted after the hot water supply is stopped. In this case, the solar water heater has a structure in which the mixed hot water flow rate value (L / min) at the time of restart is stored as an initial value, and then the latest minimum mixed hot water flow rate value (L / min) is stored as an update. However, H is the number of the heating capacity lower limit of the auxiliary heat source device,
Q indicates the flow rate of mixed hot water (L / min).