JP2003185158A - Flow detecting method for hot water heater and hot water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hot water heater capable of accurately computing the water passing flow at the terminal. <P>SOLUTION: The flow Q2 flowing through the low temperature terminal c is found not by a direct detecting means such as a flow sensor, but by the numerical expression Q2=Q1×(T1-T3)/(T3-T2) from a water passing temperature T1 detected by a temperature sensor 2, a water passing flow Q1 of a by-pass pipe F, a water passing temperature T2 detected by a temperature sensor 3, and a water passing temperature T3 detected by a temperature sensor 4. In advance, the detection errors of the respective temperature sensors 1 to 3 are computed as correction values α, β, an the correction values are used to compute the numerical expression Q2=Q1×(T1-T3-α)/(T3-T2-β). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow rate detecting method for a hot water heating system and a hot water heating system, and more specifically,
The present invention relates to a technique for detecting the flow rate of hot water flowing through a terminal in a hot water heating device without using a flow rate sensor.

[0002]

2. Description of the Related Art (Basic Structure of Hot Water Heating Device) A hot water heating device for supplying hot water to various heaters such as a hot water air conditioner, a panel heater, and a floor heating panel has been conventionally known. The heater used in such a hot water heating apparatus is classified into a high temperature terminal (such as the hot water air conditioner and the panel heater) and a low temperature terminal (such as the floor heating panel) according to the temperature of the supplied hot water. Therefore, when supplying hot water to these heaters with one hot water heater,
Conventionally, a circuit configuration as shown in FIG. 2 has been adopted.

That is, the hot water heating apparatus shown in FIG. 2 is a circuit for supplying hot water to a high temperature terminal b and a low temperature terminal c by using one heat exchanger (heat exchanging means) a. High-temperature water circulation circuit for circulating high-temperature hot water (high-temperature water) heated by the exchanger a through the high-temperature terminal b, the expansion tank d, and the circulation pump e to the heat exchanger a again (see the chain line in the figure).
And the upstream side of the heat exchanger a (specifically, the circulation pump e
And a low temperature water circulation circuit (see a chain double-dashed line in the figure) that circulates the hot water (low temperature water) branched at the downstream side) through the low temperature terminal c, the expansion tank d, and the circulation pump e to the low temperature terminal c again. There is.

Here, the expansion tank d is a replenishing water tank which is open to the atmosphere and is connected to the water supply (not shown),
The expansion tank d circulates the hot water deprived of heat at the high temperature terminal b. Further, the thermal valve g of the high temperature terminal b
A bypass pipe f is arranged between the upstream side of the expansion tank and the upstream side of the expansion tank d as a mixing bypass for the purpose of keeping the temperature of the hot water flowing into the low temperature terminal c constant.

Since the bypass pipe f is sufficiently thin, it has a substantially constant flow rate regardless of the flow rate change of the low temperature terminal c. Therefore, the flow rate of the hot water flowing through the bypass pipe f is always constant. Note that the low temperature terminal c is configured such that a plurality of terminals can be connected in parallel, and in the illustrated example, three low temperature terminals c _{1 to} c ₃ are provided, and the low temperature terminals c _{1 to} c are shown. _The thermal valves h _{1 to} h are provided on the upstream side of ₃ respectively.
_Three are provided.

(Detection of Flow Rate at Low Temperature Terminal) By the way, in the hot water heating apparatus having such a structure, control is performed to keep the pump head of the circulation pump e constant, and therefore the hot water flowing to the low temperature terminal c is controlled. Flow rate is detected.

Specifically, the temperature sensor 1 for detecting the temperature of the hot water output from the heat exchanger a and the low temperature terminal c
A temperature sensor 2 for detecting the temperature of the hot water output from the device and a temperature sensor 3 for detecting the temperature of the hot water at which the output of the bypass pipe f and the output of the low temperature terminal c merge are provided. The controller 5 of the hot water heating device is input, and the controller 5 calculates the flow rate of the low temperature terminal c.

That is, the temperature detected by the temperature sensor 1 is T
1. The temperature detected by the temperature sensor 2 is T2, the temperature detected by the temperature sensor 3 is T3, and the flow rate of the bypass pipe f is Q1.
(This Q1 has a substantially constant flow rate regardless of the flow rate change of the low temperature terminal c because the bypass pipe f is sufficiently thin. Therefore, the value is stored in the control unit 5 in advance). The flow rate Q2 flowing in c is calculated as Q2 = Q1 * (T1-T3) / (T3-T2) (1).

[0009]

However, in the configuration in which the flow rate Q2 of the low temperature terminal c is obtained by using the temperature sensors 1 to 3 as described above, the calculation result of the flow rate Q2 is distorted due to the variation (detection error) of the temperature sensor. However, there is a problem in that the detection accuracy of the flow rate Q2 decreases.

The present invention has been proposed in view of the above conventional problems, and an object of the present invention is to provide a hot water heating apparatus capable of accurately calculating the water flow rate of a terminal.

[0011]

In order to achieve the above object, a method for detecting a flow rate of a hot water heating apparatus according to the present invention comprises a first flow path which can be regarded as a substantially constant flow rate, and a second flow path A hot water heating device having a third flow passage in which the first and second flow passages merge, and a temperature detecting means for detecting the water flow temperature in each flow passage, wherein the first flow is the same. Q of flow rate
1. When the detected temperature in the first flow path is T1, the detected temperature in the second flow path is T2, and the detected temperature in the third flow path is T3, the flow rate of the second flow path (Q2) is the following formula
In the calculation according to (1), the first correction value (α) is calculated by the following equation (2) from the detected temperature detected by the temperature detecting means when the fluid having the same temperature is flown through the respective flow paths. ), The second correction value (β) is calculated by the following formula (3), and the second flow rate (Q2) is calculated by the formula (1). The above formula (1) is converted into the following formula by the first and second correction values.
It is characterized in that the flow rate (Q2) of the second flow path is calculated by performing correction as in (4). Note Q2 = Q1 × (T1-T3) / (T3-T2) ... Equation (1) α = T1-T3 ... Equation (2) β = T3-T2 ... Equation (3) Q2 = Q1 × (T1-T3-α) / (T3-T2-β) ... Equation (4)

Further, the hot water heating apparatus according to the present invention includes a hot water circulation circuit for circulating hot water output from the heat exchange means to the heat exchange means via a high temperature terminal, a replenishment tank, and a circulation pump, and the high temperature terminal. A constant flow rate bypass flow path for bypassing and supplying hot water from the heat exchange means to the replenishment tank and a part of the piping for the high temperature water circulation circuit are shared, and the upstream side of the heat exchange means is branched to a low temperature terminal and a replenishment tank. , A low temperature water circulation circuit for circulating hot water to the low temperature terminal via a circulation pump, and a temperature (T
The first temperature detecting means for detecting 1), the second temperature detecting means for detecting the temperature (T2) of the hot water output from the low temperature terminal, the constant flow rate bypass flow path and the output of the low temperature terminal. From the third temperature detecting means for detecting the temperature (T3) of the combined hot and cold water, the detected temperature of each of these temperature detecting means and the flow rate (Q1) of the constant flow rate bypass passage, the numerical formula Q1 × (T
1-T3) / (T3-T2), and a control means for calculating the flow rate (Q2) of the low-temperature terminal, wherein the control means operates the heat source of the heat exchange means and the high-temperature terminal. The first correction value (α) calculated by the mathematical expression (T1-T3) from the detected temperature detected by the temperature detecting means at that time while operating the circulation pump with the water flow to the And storage means for storing a second second correction value (β) calculated from the equation (T3-T2), and stored in the storage means when calculating the flow rate (Q2) of the low temperature terminal. It is characterized in that a control configuration for calculating the flow rate (Q2) of the low temperature terminal by the following mathematical expression based on the first and second correction values is provided. Note Q2 = Q1 × (T1-T3-α) / (T3-T2-β)

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A hot water heating apparatus to which a flow rate detecting method for a hot water heating apparatus according to the present invention is applied will be described below in detail with reference to the drawings.

An embodiment of the hot water heating apparatus according to the present invention is shown in FIG. The hot water heating device 1 is configured to detect the flow rate of the low temperature terminal c by calculation without using a flow rate sensor, and three temperature sensors 1 to 3 are provided in the hot water heating circuit. The control unit (control means) 5 of the hot water heating device is configured to perform a calculation process described later.

In addition, in the hot water heating circuit of FIG.
The same reference numerals are given to portions having the same configuration as the above, and description thereof will be omitted. Further, for convenience of explanation, the branching points or confluence points in the hot water heating circuit are denoted by reference numerals A to E, respectively.

The temperature sensors 1 to 3 are all temperature detecting means for detecting the temperature of hot and cold water flowing in the pipe, and the detected values of the temperature sensors 1 to 3 are stored in the control unit 5. It is electrically connected to the control unit 5 so as to be transmitted.

Specifically, the temperature sensor 1 is for detecting the temperature of the hot water output from the heat exchanger a, and is arranged at a position near the downstream side of the heat exchanger a in the illustrated example. Has been done. Further, the temperature sensor 2 is for detecting the temperature of the hot water output from the low temperature terminal c, and is a downstream side of the output end D of the low temperature terminal c in the illustrated example, and a confluence point with the bypass pipe f. It is arranged on the upstream side of B. Further, the temperature sensor 3 is arranged near the downstream side of the confluence point B, and is arranged so as to detect the temperature of the hot and cold water where the output of the bypass pipe f and the output of the low temperature terminal c merge.

Incidentally, the specific arrangement positions of these temperature sensors 1 to 3 can be appropriately changed as long as the temperature sensors can detect the temperature of the hot water to be detected. For example, since the temperature sensor 1 is intended to detect the output temperature of the heat exchanger a, it can be provided not only at the position shown in the drawing but also in the bypass pipe f. Further, since the temperature sensor 2 is intended to detect the output temperature of the low temperature terminal c, it can be installed at any position between the output end D of the low temperature terminal c and the junction B. Further, since the temperature sensor 3 is intended to detect the temperature of the hot water that has joined at the joining point B, it may be installed between the joining point B and the replenishment tank d.

On the other hand, the control section 5 operates the respective parts of the hot water heating system 1 (for example, the operation of the heat exchanger a and the heat operated valves g and h).
Controller, which controls the opening and closing of the circuit, the operation of the circulation pump e, and the like, and is specifically configured by a microcomputer that outputs an operation command to each of these parts as a control signal (electrical signal).

Although details of the microcomputer are not shown, as is well known, a central processing unit (CPU) for performing predetermined arithmetic processing, a storage device (ROM, RAM, etc.) for storing programs and data, and input of signals. An input / output control device (I / O port) for controlling output is configured as a main part.

The storage device (storage means) stores the control program together with the flow rate of the flow in the bypass pipe f as Q1 (this Q1 has a sufficiently narrow passage so that the flow rate is constant), as will be described later. The first correction value α, the second correction value β, and the like that are calculated by the above are stored, and the flow rate of the low temperature terminal c is calculated as follows by executing the control program.

A: Calculation of first and second correction values In calculating the correction values α and β, first, the control unit 5
Controls the combustion of a combustion device (burner) (not shown) and executes control to close the thermal valve g of the high temperature terminal b. These controls are executed by giving a predetermined control signal to the combustion device and the thermal valve g from the control unit 5 as in the normal heating operation. At that time, if the combustion of the combustion device has already stopped or the thermal valve g has already closed, control for maintaining that state is executed.

When the operation of the combustion device is stopped and water is cut off to the high temperature terminal b, the control unit 5 then outputs a control signal for instructing the circulation pump e to start the operation, and the circulation pump e. e is operated.

When the circulation pump e starts to operate, the hot water valve g is closed, so that the hot and cold water in the replenishment tank d is circulated by the circulation pump e, the branch point C, the heat exchanger a, the branch point A,
The hot water circulates through the junction B to the replenishment tank d, and the hot and cold water branched at the junction C is at the low temperature terminal c and the junctions D, E, and B.
And is circulated to the replenishment tank d.

The control unit 5 uses the following equations (2) and (3) based on the temperatures detected by the temperature sensors 1 to 3 after a predetermined time (for example, several minutes) has passed since the circulation pump e started operating. Thus, the first correction value α and the second correction value β are calculated, and the calculation result is stored in the storage device of the control unit 5. Note: α = T1-T3 ... Equation (2) β = T3-T2 ... Equation (3) In the above equation, the temperature detected by the temperature sensor 1 is T1, and the temperature detected by the temperature sensor 2 is Let T2 be the temperature detected by the temperature sensor 3 (the same applies below).

Here, in the calculation of the above equations (2) and (3), as the detected temperatures T1 to T3, the detected temperature after a lapse of a predetermined time from the operation of the circulation pump e is used. This is to make the temperature of the hot and cold water in the pipe uniform (the same temperature) by circulating. Therefore, the predetermined time is appropriately set in consideration of the inner diameter of the pipe, the length thereof, etc. within a range in which such an object can be achieved. Also,
At this time, a water supply valve (not shown) provided in the water supply tank d may be opened to drop the water of the water supply into the water supply tank d so that the detected temperature becomes the temperature of the tap water.

(B) Flow rate detection of the low temperature terminal When the first and second correction values α and β are calculated and stored in the storage device of the control unit 5, the control unit 5 thereafter controls the low temperature terminal c. The flow rate detection is performed as follows.

That is, first, the control section 5 outputs a control signal for opening the thermal valve h ₁ of the low temperature terminal c (hereinafter, the flow rate of the low temperature terminal c ₁ is detected) for detecting the flow rate. At the same time, a control signal for starting the operation of the circulation pump e is output to operate the circulation pump e to circulate the hot water in the pipe. At that time, a control signal for instructing the start of the combustion operation is also output to the above-mentioned combustion device, and the heat exchanger a
To start heating.

At this time, the control unit 5 becomes a flow rate detection target.
Low temperature terminal c₁Other than low temperature terminal c_2,c ₃For thermal valve
h_2,h₃Output a control signal to instruct the
Low temperature terminal c to detect quantity₁Other than low temperature terminal c_2,c₃To
Cut off water flow. In addition, the hot valve b of the high temperature terminal b
Even if the control signal to close the valve is output, the high temperature terminal b is output.
It is necessary to shut off the water flow in the calculation of the above correction values α and β.
It is similar to the case.

As a result, the hot water output from the heat exchanger a is guided to the replenishment tank d via the branch point A and the junction point B, as shown by the arrow in FIG. The circuit that is lowered and circulates to the heat exchanger a through the circulation pump e and the branch point C, and the hot water that is branched at the branch point C passes through the thermal valve h ₁ and the low temperature terminal c ₁ and joins at the confluence point D. , E,
It flows to the circuit led to the replenishment tank d via B. That is, at the merging point B, the hot water that has passed through the low temperature terminal c ₁ and the hot water having a constant amount of water that is supplied from the heat exchanger a through the bypass pipe (constant flow rate bypass flow path) f join together.

When hot and cold water is circulated in the pipe in this way, the following equation (4) is then calculated in the controller 5 based on the temperature detected by the temperature sensors 1 to 3 and the flow rate flowing through the bypass pipe f. Based on the above, the water flow rate of the low temperature terminal c ₃ is calculated.

Since the path of the bypass pipe f is sufficiently thin, the flow rate Q1 of the bypass pipe f is almost constant regardless of the change of the flow rate Q2 flowing to the low temperature terminal c (this flow rate Q1 is stored in the control unit 5). Therefore, the flow rate Q2 of the hot water flowing through the low temperature terminal c ₁ can be calculated using the following formula (1) as a basic formula. Note Q2 = Q1 × (T1-T3) / (T3-T2) ... Equation (1)

In this mathematical expression (1), the amount of heat (temperature × flow rate) is equal between the water entering at the junction B (water entering from the bypass pipe f and water entering from the low temperature terminal c ₁ ) and the water coming out after the joining. The flow rate Q2 of the low temperature terminal c ₁ calculated by the equation (1)
Is premised on that each of the temperature sensors 1 to 3 has no detection error.

Therefore, in the present invention, the temperature sensors 1 to
In consideration of the detection error of 3, the low temperature terminal c ₁ is calculated by using the following formula (4) in which the formula (1) is corrected by the correction values α and β.
The flow rate Q2 of is calculated. Note Q2 = Q1 × (T1-T3-α) / (T3-T2-β) ... Equation (4)

That is, here, the detection errors due to variations in the temperature sensors 1 to 3 are respectively defined as x, y, and z, and the original temperatures (true temperatures) to be detected by the temperature sensors 1 to 3 are respectively defined. Assuming T true 1, T true 2 and T true 3, the temperatures detected by the temperature sensors 1 to 3 are T 1
= T true 1 + x, T2 = T true 2 + y, and T3 = T true 3 + z, the calculation using the above formula (1) may be performed as shown in the following formula (1) ′. Error x,
y and z are added, and an error occurs in the calculation result.
Note Q2 = Q1 × [(T true 1 + x)-(T true 3 + z)] / [(T true 3 + z)-(T true 2-y)] ... Equation (1) ′

That is, in the above equation (1) ', the low temperature terminal c
_In calculating the flow rate Q2 of 1, the detection error components of the temperature sensors 1 to 3 appear as (x-z) in the numerator and (z-y) in the denominator.

On the other hand, the above equations (2) and (3) are represented by the temperature sensors 1 to
Considering the detection error of 3, the correction values α,
β is α = (T true 1 + x) − (T true 3 + z) = x−z ... Equation (2) ′ β = (T true 3 + z) − (T true 2 + y) = z−y ... (3) is replaced with ′.

Therefore, if the first correction value α is subtracted from the numerator of the mathematical expression (1) ′ and the second correction value β is subtracted from the denominator, and the mathematical expression (4) is established, the mathematical expression (1) is obtained. It is possible to remove the detection errors x, y, z of the temperature sensors 1 to 3 from '. In other words, using the above equation (4), the low temperature terminal c
By calculating the flow rate Q2 of ₁ , the temperature sensors 1-3
The error in the calculation of the flow rate Q2 due to the detection errors x, y, and z can be eliminated.

In this way, the low temperature terminal c₁Water flow
When the flow rate is detected, the control unit 5 then controls the low temperature terminal c.
_2,c₃Also for the heat valve h
_2,h ₃Sequentially open each low temperature terminal c_2,c₃Of water flow
Calculate.

As described above, in the present invention, the flow rate Q2 of the low temperature terminals c is calculated by using the above equation (4), so that even if the temperature sensors 1 to 3 are varied, the respective low temperature terminals c _{1 to} c are calculated.
The flow rate Q2 of ₃ can be accurately calculated.

The above-described embodiment is merely a preferred embodiment of the present invention, and the present invention is not limited to this, and various design changes can be made within the scope of the invention.

For example, in the above-described embodiment, the case where the flow rate detecting method of the hot water heating apparatus according to the present invention is used to detect the flow rate of the low temperature terminal c is shown. However, this flow rate detecting method is not used in the circulation circuit. It is also possible to apply it to the flow rate detection of a part. That is, the flow rate detecting method of the present invention is a case where two water inlets join to form one water outlet, and the temperature (T1) of hot water flowing in the first flow path and its flow rate (Q1),
And the temperature (T2) of the hot water flowing in the second flow path, and the hot water temperature (T3) of the flow path where these flow paths merge, the other parts of the circulation circuit (for example, It can also be applied to the flow rate detection of high temperature terminals.

Further, in the above embodiment, only the flow rate detection of the low temperature terminal c by the control unit 5 is shown, but the self-diagnosis of the hot water heating system can be performed based on the detection result. That is, it is possible to store the reference value of the flow rate of each low temperature terminal c in advance in the control unit 5 and compare the detected flow rate with the reference value to detect clogging of the pipe.

[0044]

As described in detail above, according to the present invention,
For example, in detecting the flow rate of a low temperature terminal of a hot water heater, the flow rate can be detected by calculation without using a flow rate sensor. Moreover, since the detection error such as the variation of the temperature sensor can be eliminated from the calculation formula of the flow rate, the calculation accuracy can be improved, and as a result, the accuracy of the control for keeping the out-of-machine lift of the circulation pump constant can be improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a circuit configuration of a hot water heating apparatus to which a flow rate detecting method for a hot water heating apparatus according to the present invention is applied.

FIG. 2 is a schematic configuration diagram showing a circuit configuration of a conventional hot water heating device.

[Explanation of symbols]

1-3 temperature sensor (temperature detection means) 5 Control unit (storage means) a heat exchanger b High temperature terminal c Low temperature terminal d Water tank e Circulation pump f Bypass piping (constant flow rate bypass flow path) g, h thermal valve

Continued front page    (72) Inventor Hideya Toyama             93 Edo-cho, Chuo-ku, Kobe-shi, Hyogo Stock Association             Company Noritsu (72) Inventor Atsushi Yoshimoto             93 Edo-cho, Chuo-ku, Kobe-shi, Hyogo Stock Association             Company Noritsu (72) Inventor Kazuya Kawauchi             93 Edo-cho, Chuo-ku, Kobe-shi, Hyogo Stock Association             Company Noritsu (72) Inventor Takaaki Sato             1-5-20 Kaigan, Minato-ku, Tokyo Tokyo Gas             Within the corporation F term (reference) 3L070 AA01 BB18 DD01 DE09 DF07                       DG05 DG06

Claims (2)

[Claims] 1. A first flow path that can be regarded as a substantially constant flow rate,
In a hot water heating device having a second flow path and a third flow path where these first and second flow paths merge, each temperature path is provided with a temperature detecting means for detecting the water flow temperature. Therefore, the flow rate of the first flow path is Q1, and the temperature detected in the first flow path is T
1. When the detected temperature in the second flow path is T2 and the detected temperature in the third flow path is T3, the flow rate of the second flow path (Q
2) is calculated by the following mathematical expression (1), the fluid having the same temperature is made to flow through each of the flow paths, and the detected temperature detected by each of the temperature detecting means at that time is calculated by the following mathematical expression (2). The first correction value (α) is calculated, the second correction value (β) is calculated by the following formula (3), and the flow rate (Q2) of the second flow path is calculated by the formula (1). At the time of calculation, the flow rate (Q2) of the second flow path is calculated by correcting the formula (1) with the first and second correction values as the following formula (4). Method for detecting a flow path of a hot water heater. Note Q2 = Q1 × (T1-T3) / (T3-T2) ... Equation (1) α = T1-T3 ... Equation (2) β = T3-T2 ... Equation (3) Q2 = Q1 × (T1-T3-α) / (T3-T2-β) ... Equation (4) 2. A high-temperature water circulation circuit for circulating hot water output from the heat exchange means to the heat exchange means via a high-temperature terminal, a replenishment tank, and a circulation pump, and a bypass tank for bypassing the high-temperature terminal to the replenishment tank. A constant flow rate bypass flow path for supplying hot water to the high temperature water circulation circuit and a part of the piping are shared, and the upstream side of the heat exchanging means is branched to a low temperature terminal, a replenishment tank, and a circulation pump to cool A low-temperature water circulation circuit for circulating hot water to the terminal, a first temperature detection means for detecting the temperature (T1) of the hot water output from the heat exchange means, and a temperature (T2) of the hot water output from the low-temperature terminal. The second temperature detecting means for detecting, the temperature of the hot water at which the constant flow bypass flow passage and the output of the low temperature terminal merge (T3)
For detecting the temperature, the temperature detected by each of these temperature detecting means, and the flow rate (Q1) of the constant flow rate bypass passage.
From the equation Q1 × (T1−T3) / (T3−T2) to a controller for calculating the flow rate (Q2) of the low temperature terminal, the controller includes a heat source for the heat exchanging means. The circulation pump is operated in a state in which the operation and the passage of water to the high-temperature terminal are stopped, and at that time, the first temperature calculated by the formula (T1-T3) from the detected temperature detected by each of the temperature detecting means. Storage means for storing the correction value (α) and the second second correction value (β) calculated from the equation (T3-T2),
When the flow rate (Q2) of the low temperature terminal is calculated, a control configuration for calculating the flow rate (Q2) of the low temperature terminal based on the first and second correction values stored in the storage means is used. Characteristic hot water heating system. Note Q2 = Q1 × (T1-T3-α) / (T3-T2-β)