KR940004174B1 - Temperature control device for hot water supply equipment - Google Patents

Abstract

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Description

Temperature controller of hot water heater

1 is a functional block diagram showing a functional configuration in the control device of the gas-fired hot water heater of this embodiment.

2 is a schematic configuration diagram showing an outline of a gas combustion hot water heater of this embodiment.

3 is a flowchart for explaining a process of calculating the acquisition temperature in the control device of this embodiment.

4 is an area map showing the gear area of the heating amount storage unit of this embodiment.

5 is a time chart showing a change in heating amount output information in the control device of this embodiment.

6 is a time chart showing the change in the estimated quantity by the quantity estimation of the present embodiment.

7 is a time chart showing changes in tapping temperature with respect to quantity in this embodiment.

8 is a characteristic diagram showing a relationship with the initial quantity WP ₂ estimated by the elapsed time (tm) by the time-keeping part in the initial quantity estimation part of this embodiment.

FIG. 9 is a time chart showing changes in tapping temperature corresponding to the quantity of water during reheating.

10 is a flowchart showing the process of estimating the quantity in this embodiment.

* Explanation of symbols for main parts of the drawings

11: burner group (heating means) 13: heat exchanger

19: water flow switch (water flow detection means) 25: tapping temperature thermistor (temperature sensor)

30: controller (temperature controller of the hot water heater)

33: initial quantity estimation unit (flow estimation unit) 33a: timekeeping unit (revelation unit)

The present invention relates to a temperature control device for a hot water heater, which does not provide a flow sensor for detecting the flow rate of water passing through the heat exchanger, and in particular flows out from the heat exchanger without installing an inlet temperature sensor for detecting the temperature of the water flowing into the heat exchanger. It is effective in a simple hot water heater having a structure having only an outflow temperature sensor that detects the temperature of hot water.

In order to simplify the structure of the hot water heater, simplify the manufacturing process, and reduce the manufacturing cost, there is a temperature control device for feedback control by the tapping temperature thermistor. In such a temperature control device, an inlet temperature thermistor which detects the inlet temperature to the heat exchanger and a flow sensor for detecting the flow rate of the water passing through the heat exchanger are not provided, so that the one having the function to improve the tapping temperature characteristics is used. have.

In the temperature control device of such feedback control, when the amount of heating is controlled as it is by the outflow temperature which is not heated at the beginning of the hot water supply, the amount of hot water is small, or excessive heating occurs when there is "boiling behind" in the hot water supply. There exists a possibility that a tapping temperature may become high too much by this. For this reason, in order to avoid danger, the amount of ignition is set a little on the premise that the amount of the hot water supply is low or that the water in the heat exchanger is heated due to "boiling behind", and then a constant time by the time constant of the feedback control system. As the delay occurs, the heating amount gradually changes in response to the detection temperature by the tapping temperature sensor.

As described above, in the conventional hot water supply of feedback control, the information for controlling the heating amount is given only by the tapping temperature sensor, and since there is no information on the flow rate of the water passing through the heat exchanger, the amount of heating is large when the hot water supply amount is large at the beginning of the hot water supply. Lack. Therefore, the rise of the tapping temperature becomes slow, and the time until the tapping temperature rises to the target temperature and stabilizes becomes long. Especially in the re-hot water supply, the initial hot water supply is affected by the mutual relationship between the amount of hot water supply and the actual temperature of the water remaining in the heat exchanger. In this case, to prevent excessive heating, the amount of heating is insufficient when the hot water supply amount is large. The problem is that the response delay is larger because it is not given.

The present invention provides a temperature control apparatus for a hot water heater, which has a good rise characteristic of the tapping temperature of the initial hot water supply in the case of a re-hot water supply, especially in a case of a large amount of hot water supply, in a hot water supply machine for feedback control without a flow sensor. For the purpose of

The present invention has a water flow detecting means for detecting the inflow of water into the heat exchanger, and in response to the water flow detecting state of the water flow detecting means, controlling the start and stop of heating of the heat exchanger by the heating means, and simultaneously A temperature control device of a hot water heater for controlling the heating amount of the heating means based on temperature information detected by a temperature sensor provided at an outlet of the machine, comprising: time-keeping means for counting a predetermined time after the start of hot water supply, and passing through the heat exchanger; A flow rate estimating means for estimating the flow rate of water is provided, and the flow rate estimating means is a technical means for estimating the flow rate on the basis of the falling state of the detection temperature of the temperature sensor when the predetermined time after the start of hot water supply has elapsed.

In general, in a hot water heater, there is a time delay until the start of heating is detected after the inflow of water to the heat exchanger is detected. On the other hand, there is a time delay until the result of heating by the heating means appears at the tapping temperature. This delay is different depending on the flow rate through the heat exchanger.

Therefore, when the hot water supply is started again after the hot water supply is stopped, the temperature of the water flowing out of the heat exchanger is lowered once even if the water in the heat exchanger is heated by the heat of the heat exchanger or the like. Temperature rises. In this case, the fall change state of the outflow temperature changes depending on the flow rate through the heat exchanger, and when the flow rate is large, the degree of fall (gradation) is large, and when the flow rate is small, the degree of fall (gradation) is small (Fig. 9). Reference).

The present invention detects the falling state as the falling gradient of the degree of outflow at a predetermined time before the temperature rise by heating appears, and estimates the flow rate based thereon.

In the present invention, the flow rate is estimated by the falling state of the detection temperature as the outflow temperature when a predetermined time elapses after the start of the hot water supply. The lowered state of the outflow temperature is faster than the temperature increase usually associated with the start of heating. Therefore, when re-hot water is performed, the flow rate can be estimated earlier than in the case of normal hot water without heating by excess heat.

Therefore, since the heating amount can be controlled in accordance with the flow rate at the early stage of the heating start, the tapping temperature can be increased quickly. In particular, when the flow rate is large, a large heating amount corresponding to the flow rate can be given, so that the increase in tapping temperature in the case of large flow rate is greatly improved as compared with the conventional one.

EXAMPLE

Next, a description will be given based on the embodiment showing the temperature control device of the hot water heater of the present invention.

In the combustor case 10 of the gas-fired hot water heater 1 shown in FIG. 2, the burner group 11 which has arrange | positioned the some burner is provided. In the lower part of the combustor case 10, the blower 12 for supplying combustion air to the burner group 11 is provided. A water pipe type heat exchanger 13 is installed above the burner group 11 in the combustor case 10, and water passing through the inside is heated due to the heat of combustion by the burner group 11. In the vicinity of the burner group 11 in the combustor case 10, a sparker 14 for igniting the burner group 11 and a flame rod 15 for detecting the ignition of the burner group 11 are provided. In addition, an exhaust port 2 for discharging combustion flue gas to the outside is provided above the combustor case 10.

A nozzle tube 16 for supplying fuel gas is prepared below the burner group 11, and a plurality of fuel ejection ports for ejecting fuel gas corresponding to each burner of the burner group 11 are provided in the nozzle tube 16, respectively. 16a is provided.

The fuel pipe 20 which guides the fuel gas to the nozzle pipe 16 has two solenoid valves 21 and 22 which allow the fuel gas to pass through at the time of energization, and controls the supply pressure of the fuel gas by controlling the supply pressure in response to the energization current. Control proportional valves 23 are provided in order from the upstream side, respectively.

The water supply pipe 17 leading water from the water supply source (not shown) to the heat exchanger 13 includes an electric water flow control unit 18 for adjusting the amount of hot water supply and a water flow switch for detecting water passing through the heat exchanger 13. The tapping temperature (Tout) of the hot water flowing out from the heat exchanger (13) is provided in the hot water supply pipe (17a), which is provided sequentially from the upstream side, and directs the hot water flowing out of the heat exchanger (13) to the hot water supply port (not shown). The tap-on thermistor 25 which detects) is prepared.

The control device 30 has a control circuit centered on a microcomputer, and starts and stops combustion in a predetermined sequence in response to the water flow detection state of the water flow switch 19, and at the same time, the functional configuration shown in FIG. Thus, the temperature of tapping water is controlled using only the tapping temperature thermistor 25 as a sensor.

In this case, since the inlet temperature thermistor to the heat exchanger 13 and the flow rate sensor for detecting the quantity of water passing through the heat exchanger 13 are not provided, the controller 30 detects the detection temperature of the tapping temperature thermistor 25. Based on (T), the acquisition temperature (Tin) and the quantity (W) are estimated, respectively. The acquisition temperature estimation unit 31 estimates the acquisition temperature Tin based on the detection temperature T of the tapping temperature thermistor 25 and stores it in the memory 31a.

Next, the estimation method of the acquisition temperature Tin is demonstrated according to FIG.

When the start of the hot water supply is detected by the water flow switch 19 (YES in step 1), it is considered that the hot water supply temperature is changed to be a hot water supply when the detection temperature T of the tapping-on thermistor 25 changes. Therefore, when there is a temperature gradient in the detection temperature T (NO in step 2), the acquisition temperature Tin is not estimated.

If the temperature gradient is not detected when the start of the hot water supply is detected (YES in step 2), the detection temperature T of the hot water temperature thermistor 25 and the acquisition temperature Tin are already present in the memory 31a. Compared with the stored memory temperature Tmem (step 3), when the detection temperature T is lower than the memory temperature Tmem (YES in step 3), the detection temperature T is changed to the new acquisition temperature Tin. Is estimated (step 4), and the stored contents of the memory 31a are updated (step 5).

If the detection temperature T is higher than the storage temperature Tmem (NO in step 3), a part of the temperature information of the detection temperature T is accepted in the storage temperature Tmem to estimate the new acquisition temperature Tin. (Step 6), and set it as the storage temperature Tmem (step 5).

In step 6, the new acquisition temperature Tin is obtained from a part of the temperature information of the storage temperature Tmem and a part of the temperature information of the detection temperature T. Tin = (a × Tmem-b × T) / (a + The new acquisition temperature Tin is calculated by b).

The quantity estimating unit 32 estimates the quantity of water WP ₁ passing through the heat exchanger 13 at the time of normality.

In general, the temperature rise ΔT of the hot water flowing out of the heat exchanger 13 is also a result of being heated by the burner group 11 until water flows into the heat exchanger 13 and flows out. Now, if time t is required for water (Wu) per unit time to pass through the heat exchanger (13), at this time, it is involved in the temperature rise (ΔT) of the hot water flowing out of the heat exchanger (13). One total heating amount Q _T can generally be expressed as, for example, the product of the heating amount Qu per unit time and the heating time t (the time t required to pass through the heat exchanger). In other words,

Represented by

Here, Quxt refers to the multiplication of the heating amount Qu per unit time in the heating time t.

Therefore, the heating amount during the heating time t having the total heating amount Q _T from the time t ₁ to the time t _n is changed, so that the heating amount Q _n per unit time is not constant. To display,

It becomes

Where Q _n , Q _n-1 , Q _n-2 ,... Q ₂ , Q ₁ represents each unit time t _n , t _n-1 , t _n-2 ,... In, t ₂ , t ₁ , the heating amount is indicated.

In addition, the total heating amount Q _T by the burner group 11 is considered to have acted on the temperature rise ΔT of the total amount U of the heat exchanger 13 according to the volume of the heat exchanger 13. Because I can

It becomes Therefore, in equation ② and equation ③,

As a result, when the time was retroactively multiplied by the amount of heating for each unit time, heating corresponding to the total amount of heating Q _T that gave the temperature rise of ΔT to the total amount of water U in the heat exchanger 13 was heated. If the sum of the unit time until the quantity is obtained, it can be set as the heating time t.

In addition, this heating time t is the time required for water to pass through the heat exchanger 13, and the amount of water W between the total amount U of the heat exchanger and the quantity W of water.

By having a relationship with

The flow rate W can be obtained by this.

In this case, the constant of the delay time accompanying the response delay of heating may be added.

In the water quantity estimating unit 32, the temperature rises (ΔT) from the detection temperature T of the tapping temperature thermistor 25 and the acquisition temperature Tin stored in the memory 31a of the acquisition temperature estimation unit 31. From the total amount U in the heat exchanger 13, the total amount of heat Q _T is calculated by the above equation (3).

On the other hand, the area E1 of the heating amount storage part 32a which shows heating amount output information (DELTA) Q for every predetermined unit time (DELTA) t by the temperature control part 34 mentioned later in FIG. 4, and the area | region ( E2),... The data is sequentially stored in the area Ex, accumulated for a predetermined time, and deleted for each time new information is given.

That is, for example, the heating amount output information ΔQ for each predetermined unit time Δt by the temperature control unit 34 is shown in FIG. DELTA Q _n-4 , DELTA Q _n-3 , DELTA Q _n-2 , DELTA Q _n, DELTA Q _n-1 , DELTA Q _{n + 1} , DELTA Q _{n + 2} ,. In the case of the change as shown in FIG. 2, at the time t _n , in the heating amount storage unit 34, as shown in a of FIG. 4, the area E1 is ΔQ _n at the time Δt _n , and the time Δ is at the time E _n . t _n-1 Q _n-1 is the area (E3) according to, the △ Q _n-2 at time △ t _n-2, the area (E4), the △ Q _n-3 at a time △ t _n-3 is Up to the area Ex, the heating amount output information ΔQ before the time Δt _n is stored in correspondence with each area E. FIG.

Then, the next time △ t _{n + 1,} the first being stored in 4b FIG area (E1) to the city As, time △ heating amount information output △ Q _{n + 1} according to t _{n + 1,} the following △ Q _n is ? Q _n-1 in area E2 is in area E3,? Q _n-2 is in area E4. The heating amount output information ΔQ of each area E is shifted and stored at each time t to the area E _{X in the} same manner as described below.

Thereafter, in the same manner, the newest heating amount output information ΔQ is always stored in the area E1, and the stored information in the area E _X is deleted, so that the heating amount for each predetermined unit time Δt. Output information DELTA Q is continuously stored and stored.

The quantity estimating unit 32 multiplies the stored heating amount output information ΔQ in this order from the new information, and the predetermined unit time Δt at the same time as the calculated total heating amount Q _T is obtained by the above formula (2). The total is found as the heating time t of the water flowing out of the heat exchanger 13.

Based on this heating time (t), the quantity (W) of water passing through the heat exchanger (13) is calculated by Equation (6) above.

The quantity WP ₁ estimated here is a numerical value as the average quantity W in the heating time t. When the hot water supply water W is sequentially changed, the quantity W is measured at each time. Can not be represented.

The quantity estimating unit 32 calculates the heating time t that is effective only when the storage amount output information ΔQ stored in the storage is multiplied by the new information in order, and becomes equal to the total heating amount Q _T. To lose. Therefore, for example, in the initial hot water supply, even if the heating quantity output information ΔQ is to be multiplied until it becomes equal to the total heating amount Q _T , the estimated quantity WP ₁ may not be retroactively before the hot water is started. It is much larger than the quantity (W). When this state is displayed, it is as shown in FIG. In FIG. 6, for example, the solid line C represents a logarithmic amount, and the solid line D represents a small amount.

Here, the quantity WP ₁ estimated by the quantity estimating unit 32 replaces the actual quantity W, and indicates effective quantities Wc and Wd, respectively, at time tc, This is when the time td has elapsed. For this reason, in the temperature control based on the quantity WP ₁ from the start of the hot water supply to the time ttc and the time td, respectively, the appropriate heating amount Q Cannot be determined.

Therefore, in the present embodiment, the amount of water WP passing through the heat exchanger 13 by the initial quantity estimating portion 33 instead of the quantity P1 estimated by the quantity estimating portion 32 described above only in the initial hot water supply. ₂ ) is estimated.

That is, the tapping temperature Tout after the start of the hot water supply is represented by the change according to the quantity W as shown in FIG. 7, for example, in the case of a large quantity, it rises relatively quickly, as indicated by the solid line E. In the case of, ascending by the solid line F, the increase is slow compared to the case of algebraic quantity.

The initial quantity estimating unit 33 calculates the initial quantity WP ₂ based on the time that the amount of heat given to the heat exchanger 13 is represented as a change in the tapping temperature Tout depends on the amount W passing therethrough. By estimating, the elapsed time (tm) until the predetermined amount of heat by heating is detected by the timekeeping section 33a, and the quantity WP ₂ is estimated.

In this case, a multiplication value P (integral value with respect to dry land temperature T) obtained by multiplying the temperature rise (T) of the detection temperature (T) with the start of hot water supply as a given predetermined amount of heat is obtained, and this multiplication is performed. The elapsed time tm until the value P is written by the predetermined multiplication value Po is counted.

The predetermined multiplication value Po indicates the calorie value of a certain time given to the heat exchanger 13 at the same time as the start of combustion. In FIG. 7, for example, in the case of a large quantity, the area S ₁ up to the time te is shown. It intended to show that a considerable amount of heat, is represented by the amount of heat corresponding to the area (S ₂₎ by the time (tf) in the case of small quantities. In particular, a value corresponding to a relatively short time heating amount after commencement of combustion is set here so that it is possible to clearly detect the difference in the amount of water W actually passing through the heat exchanger 13.

In response to this time elapsed time tm, the quantity WP ₂ is estimated as shown in FIG.

As a result, each time counting can be completed relatively early before the tapping temperature is stabilized in each water quantity W. As shown in FIG. In particular, in the case of large quantities, as shown in FIG. 7, the time is completed much faster than the time td at which the tapping temperature is stable in the case of a small quantity, and as a result, it is possible to detect that the large quantity.

In FIG. 7, the times tc and td respectively represent the same time as the times tc and td in FIG.

Therefore, for reference, each time (te, tf) for ending the time in each quantity in FIG. 7 represents the same time as the time (te, tf) in FIG. 6, where As is apparent, it can be seen that these times te and tf are the time until the quantity WP ₁ estimated in the quantity estimating 32 represents a certain quantity value W _X.

In addition, in the initial quantity estimating section 33, in order to more quickly estimate the quantity W at the time of the hot water supply, the temperature rise accompanying the time of heating is started by the time-keeping part 33a which shows the elapsed time tm after the start of the hot water supply. It is determined whether or not a downward gradient appears in the change in the detection temperature T when the initial time (to) before the time appears, and, if there is a downward gradient, the quantity (W) based on the downward gradient (G). estimated by the initial quantity (WP _O) at the time of re-hot water supply, and the estimation of the initial quantity (WP ₂₎ of the above is performed.

The downward gradient (G) of the temperature changes in response to the quantity (W) as shown in FIG. 9, where the larger the gradient (G) is, the larger the quantity (W), and the smaller the downward gradient (G), the quantity (W). Estimate each initial (WP ₀ ) so that

The temperature control unit 34 includes the target temperature set by the controller 40, the tapping temperature Tout detected by the tapping temperature thermistor 25, and the inlet temperature Tin detected by the inlet temperature estimation unit 31. , The amount of heating Q is determined from the quantity WP ₁ and the initial quantity WP ₂ · WP ₀ estimated by the quantity estimating unit 32 and the initial quantity estimating unit 33, respectively.

In this case, immediately after the start of hot water supply, the starting amount of water (Ws) of the water flow switch 19 is set as the amount of water W passing through the heat exchanger 13, and the estimated inlet temperature Tin and the target temperature of the controller 40 (Test) Determine the heating amount Q based on

Then, when the downward gradient G of the detection temperature T appears or the multiplication value reaches a predetermined multiplication value Po, the initial quantity W ₂ or the initial quantity estimated by the initial quantity estimating unit 33 WP _{0 is} determined as the quantity W, and the heating amount Q is determined, and when the time tp determined based on these quantities WP ₂ · WP ₀ has elapsed, the quantity estimated 32 is estimated. The quantity of heating W is determined by making the quantity WP _{1 the} quantity W. FIG.

If the detection temperature T of the tapping-on thermistor 25 rises to a constant temperature, feedback control is performed based on the detection temperature T. FIG.

In this feedback control, stable temperature control is performed by setting the time constant of the feedback control system at that time based on the quantity WP ₁ estimated by the above-described quantity estimating unit 32, so that hunting and the like are not caused. Therefore, stable temperature control is achieved even when the time constant of the feedback control system changes with the change in quantity. Then, the heating amount Q of the temperature controller 34 is the heating amount output information ΔQ, and is sequentially stored in the heating amount storage unit 32a described above every predetermined unit time Δt.

The driving unit 35 drives and controls the blower 12 and the control proportional valve 23 based on the heating amount Q of the temperature controller 34. Here, the voltage based on the heating amount Q by the temperature control part 34 is applied to the blower 12, and it drives, and it energizes the electric current value to the control proportional valve 23 based on the rotation speed of the blower 12 detected. To control.

In addition, the controller 30 restricts the passage flow rate by adjusting the opening degree of the electric water flow controller 18 based on the detection temperature T of the tapping temperature thermistor 25 so that the water supply does not exceed the heating capacity. .

And the controller 40 which can set the target temperature Test arbitrarily by a user is installed according to the specification of a hot water heater, and when the controller 40 is installed, the target temperature Test is set according to a user's operation, When the controller 40 is not installed, a predetermined temperature (eg, 60 ° C.) is set as the target temperature (Test).

Next, in the gas-fired hot water heater 1 of the present embodiment having the above configuration, the temperature control will be described with reference to FIG. 10 centering on the estimation of the quantity W. FIG.

When the user opens the hot water supply (not shown) installed downstream of the hot water supply pipe 17a, water passes through the water supply pipe 17 and flows into the heat exchanger 13.

When hot water supply is detected by the water flow switch 19 (YES in step 11), ignition control is performed in a predetermined sequence, and combustion starts, and at the same time, the elapsed time tm is displayed by the starter 33a. Is started (step 12). At this time, only when the tapping temperature Tout does not change, the inlet temperature Tin is estimated in response to the detection temperature T of the tapping temperature thermistor 25, and the memory temperature Tmem of the memory 31a is updated. .

After the counting time, when the initial time to elapses (YES in step 13), it is determined whether there is a downward gradient G of the detection temperature T, and when there is a downward gradient G (step 14). In the case of YES), the initial amount WP ₀ is estimated based on the downward gradient G as the hot water supply (step 15).

If there is no downward gradient G (NO in step 14), the temperature rise T for each predetermined unit time t of the detection temperature T of the tapping-temperature thermistor 25 is multiplied to multiply it. ) Is calculated (step 16), and when the multiplication value P is equal to or greater than the predetermined multiplied value Po (YES in step 17), the time is terminated at the elapsed time tm by the timekeeping section 33a (step) 18) The initial amount WP ₂ is estimated based on the time elapsed time tm (step 19).

When the initial quantity (WP ₀₎ or initial quantity (WP ₂₎ estimate for each initial quantity (WP _-) on the basis of · (WP _2), the initial time (tp) is set (step 20).

When the initial time tp has elapsed (step 21), control by the quantity WP ₁ estimated by the quantity estimating unit 32 is started (step 22), and the heating amount (P1) is subsequently determined by the quantity WP ₁ . Q) is determined.

Since the quantity WP ₁ obtained here is used as a time constant in the feedback control, for example, when the tapping temperature is changed by the flow rate change, the heating amount Q can be corrected by the time constant corresponding to the flow rate change. Therefore, hunting and the like due to the correction of the heating amount hardly occur.

When hot water supply is closed and hot water supply is stopped (YES in step 23), combustion stops.

As described above, according to this embodiment, since the quantity of water is estimated quickly at the beginning of hot water supply, the appropriate heating amount is determined. In particular, in the case of re-water supply, since the quantity is estimated earlier than in the case of normal hot water supply, the higher the quantity, the sooner the temperature control is started based on the estimated quantity. Therefore, the rise of tapping temperature improves compared with the conventional case.

In this embodiment, only the tapping-on thermistor is provided as the sensor, and since the sensor is not installed at the inlet of the heat exchanger, the structure of the hot water heater is simplified, the manufacturing process is simplified, and simple feedback control is equivalent to the hot water heater. The tapping temperature characteristic close to the feedforward control, which is very stable in structure, is obtained.

In the above example, although the gas water heater using the burner which uses gas as a fuel was shown, the burner by other raw materials, such as petroleum, may be used. In addition, a heating source is not limited to a combustion apparatus, The hot water heater by electric heating may be sufficient.

Claims (1)

A water flow detection means for detecting the inflow of water into the heat exchanger is provided, and in response to the water flow detection state of the water flow detection means, the heating means starts and stops control of the heat exchanger, and at the same time, outflow of the heat exchanger. A temperature control device of a hot water heater for controlling the heating amount of the heating means based on temperature information detected by a temperature sensor provided in the unit, comprising: a time-limiting means for counting a predetermined time after the hot water supply and the flow rate of water passing through the heat exchanger; And a flow estimating means for estimating, wherein the flow estimating means estimates the flow rate on the basis of the falling state of the detection temperature of the temperature sensor when the predetermined time elapses after the start of the hot water supply. .

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