KR940004173B1 - Temperature control device for hot water supplying 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 the present embodiment.

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

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

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

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

6 is a time chart showing a change in the estimated quantity by the quantity estimating unit 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 quantity WP ₂ estimated by the time elapsed by the timekeeping section in the initial quantity estimating section of this embodiment.

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

* Explanation of symbols for main parts of the drawings

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

30 control device (temperature control device of the hot water heater)

33: initial quantity estimating part (flow rate estimating means) 33a: timekeeping part (time-measuring means)

The present invention relates to a temperature control device for a hot water heater without a flow sensor for detecting the flow rate of water passing through the heat exchanger, and in particular, without installing an inlet temperature sensor for detecting the temperature of water flowing into the heat exchanger. It is effective in a simple hot water heater having a structure only with an outflow temperature sensor that detects the temperature of hot water flowing out from the 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 controlling the feedback by the tapping temperature thermistor. In such a temperature control device, the inlet temperature thermistor for detecting the inlet temperature to the heat exchanger and the flow sensor for detecting the flow rate of the water passing through the thermal bridge are not provided, and thus have a function for improving the tapping temperature characteristics. Is used.

In addition, in the temperature control device of such a feed back system, if the amount of heating is controlled as it is based on the outflow temperature that is not heated at the beginning of hot water supply, the hot water temperature may be excessively increased due to excessive heating when the amount of hot water is small. In order to avoid the heating amount, the heating amount is set on the premise that the hot water supply amount is small. Then, the heating amount is gradually changed while following a certain time delay by the time constant of the feedback control system in response to the detection temperature by the tapping temperature sensor.

As described above, in the conventional hot water heater of the feed back control, since the information for controlling the heating amount is given only by the tapping temperature sensor, and there is no information about the flow rate of the water passing through the heat exchanger, the response delay is no matter how much the flow rate changes. In the case of a large amount of hot water supply at the beginning of hot water supply, the heating amount is insufficient, so that the temperature of the tapping temperature rises slowly, and the time until the tapping temperature rises to the target temperature and becomes stable is long.

SUMMARY OF THE INVENTION An object of the present invention is to provide a temperature control device for a hot water heater, which has a good rise characteristic of the tapping temperature at the beginning of the hot water supply, and is particularly excellent in the case of a large amount of hot water supply in a hot water heater that does not have a flow sensor and performs feedback control. .

According to a first aspect of the present invention, when a hot water supply is detected by a water flow detecting means for detecting the inflow of water into a heat exchanger, the temperature sensor is provided to start the heating of the heat exchanger by a heating means, and is provided in the outlet of the heat exchanger. A temperature control device of a hot water heater, which controls the heating amount of the heating means based on temperature information detected by the above, comprising: time-keeping means for counting an elapsed time after the start of hot water supply, and a flow rate estimating means for estimating a flow rate of water passing through the heat exchanger The flow rate estimating means is a technical means for estimating the flow rate based on the time from when the hot water is started until the detection temperature of the temperature sensor shows a predetermined change.

According to a second aspect of the present invention, the flow rate measuring means uses the technical means for estimating the flow rate based on the time until the integrated value of the change in the detection temperature of the temperature sensor becomes a predetermined value.

In general, in the hot water heater, there is a time delay before the heating result appears in the tapping temperature. In the case of non-reheating, the time from starting the hot water supply until the tapping temperature appears is the time required for water to pass through the heat exchanger. .

The passage time of this water varies, for example, by the flow rate through a water pipe-type heat exchanger having a constant length. In the case of large quantities, the time from entering and exiting the heat exchanger is short, The time becomes long.

In light of the characteristics of such a hot water heater, in the first invention, the temperature of the water flowing out from the heat exchanger is detected by a temperature sensor, and after the start of the hot water supply, the temperature of the water flowing out increases and the detection temperature of the temperature sensor shows a predetermined change. The flow rate of the water passing through the heat exchanger is estimated based on the time of, for example, the time until the temperature rise of the outflowing water is detected.

Further, in the second invention, the integrated value of the change in the detection temperature of the temperature sensor as the cumulative amount of heat given to the water passing through the heat exchanger is obtained, and the flow rate is estimated by the time until the integrated value becomes a predetermined value. The difference of the amount of change of detection temperature by the difference can be made clear.

In the first invention of the present invention, since the flow rate is estimated at the time when a predetermined change occurs in the outflow temperature after the start of hot water supply, the heating amount of the heating means can be controlled quickly in response to the flow rate. In particular, since the larger the flow rate, the faster the flow rate estimation can be, the increase in tapping temperature in the case of large flow rate is greatly improved as compared with the conventional one.

In the second invention, since the integrated value of the detected temperature change as the cumulative value of the amount of heating to water is used, it is possible to clearly grasp the difference in the flow rate. Therefore, each flow volume can also be specified also about the difference of a some flow volume.

EXAMPLE

Next, it demonstrates based on the Example which shows the temperature control apparatus of the hot water heater of this invention.

In the combustor case 10 of the gas-fired hot water heater 1 shown in FIG. 2, a plurality of burner groups 11 in which a plurality of burners are arranged are 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 provided 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 water parker 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. The control proportional valve 23 is provided in order from the upstream, 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 hot water supply amount and a water flow switch for detecting water passing through the heat exchanger 13. A hot water tapping temperature (Tout) of the hot water flowing out of the heat exchanger (13) is provided in the hot water 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. The temperature control of the tapping water is performed using only the tapping temperature thermistor 25 as a sensor.

Here, since there is no flow sensor for detecting the temperature of the water inlet to the heat exchanger 13 and the quantity of water passing through the heat exchanger 13, the control device 30 detects the tapping temperature thermistor 25. Based on temperature T, the acquisition temperature Tin and the quantity W are estimated, respectively.

The acquisition temperature estimation part 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 hot water temperature 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.

When the temperature gradient is not detected when the start of hot water supply is detected (YES in step), the detection temperature T of the tapping-on thermistor 25 is already stored in the memory 31a as the acquisition temperature Tin. When the detection temperature T is lower than the storage temperature Tmem (YES in step 3) compared with the existing storage temperature Tmem (step 3), the detection temperature T is used as the new acquisition temperature Tin. It estimates (step 4) and updates the memory content of the memory 31a (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 a new acquisition temperature Tin. (Step 6), and let it be the storage temperature Tmem (step 5).

In step 6, the new estimated 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 W passing through the heat exchanger 13.

Generally, 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, assuming that time t is required for water (Wu) per unit time to pass through the heat exchanger 13, at this time, the temperature of the hot water flowing out of the heat exchanger 13 (ΔT) The total heating amount Q _r can generally be expressed as 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), for example. 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, when the total heating amount Q _T is displayed including the case where the heating amount changes from the time t ₁ to the heating time t of the time tn, and the heating amount Qn per unit time is not constant. ,

It becomes

Where Qn, Qn- ₁ , + Qn- ₂ ,... Q ₂ , Q ₁ is the unit time tn, tn _-1 ,. The heating amount in, t ₂ and t ₁ is indicated.

The total heating amount Q _T by the burner group 11 can be regarded as acting 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 of,

It becomes Therefore, in Equation ② and Equation ③

As a result, when the amount of heating for each unit time is accumulated retroactively, the amount of heating corresponding to the total heating amount Q _T , which gives a temperature rise of ΔT to the total amount U of the heat exchanger 13, is obtained. When the sum of the unit time until it is obtained, it can be made into heating time t.

In addition, this heating time (t) is a time required for water to pass through the heat exchanger (13), and basically between the total amount of water (U) and the flow rate (W) in the heat exchanger (13).

By having a relationship with

The flow rate W can be obtained by this.

In this case, the constant of the time delay associated with the passage of water may be added.

In the water quantity estimating unit 32, the temperature rise ΔT is determined from the detection temperature T of the tapping temperature thermistor 25 and the intake temperature Tin stored in the memory 31a of the intake temperature estimating unit 31. The total heating amount Q _T is calculated from the total water amount U in the heat exchanger 13 by the above equation ③.

On the other hand, area E1 and area of the heating amount storage part 32a which show heating amount output information (DELTA) Q for every predetermined unit time (DELTA) t by the temperature control part 34 mentioned later in FIG. (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 changed with time as shown in FIG. ΔQn ₋₄ , ΔQn ₋₃ , ΔQn ₋₂ , ΔQn ₋₁ , ΔQn, ΔQn ₊₁ , ΔQn ₊₂ ,. In the case of the change as shown in the figure, in the heating amount storage unit 32a at the time Δtn, as shown in a of FIG. 4, ΔQn is shown in the area E1 at time tn, and in the area E2 at time Δ. in △ tn _{-1 -1} Qn is, the area (E3), the at time tn △ _{-2 -2} △ Qn the area (E4), the Qn △ △ _-3 At time tn _-3, less than the area (Ex ), Each heating amount output information ΔQ before time Δtn is stored corresponding to each area E.

And, in the next time following the △ tn _+1, As illustrated in Figure 4b, the amount of heat generated at time tn △ △ Qn _{+1 +1} output information stored in the area (E1), or less △ Qn this area (E2) ΔQn ₋₁ in the area E3, ΔQn ₋₂ in the area E4. In the following manner, the heating amount output information ΔQ of each area E is shifted and stored up to the area Ex at the time Δt.

Thereafter, in the same manner, the newest heating amount output information ΔQ is always stored in the area E1, and the storage information of the area Ex is deleted, thereby outputting the heating amount for each predetermined unit time Δt. The information DELTA Q is continuously stored and stored.

The quantity estimating unit 32 adds the heating amount output information ΔQ thus stored in this order from the new information, and totals the predetermined unit time Δt when it is equal to the total heating amount Q _T calculated by the above equation ②. Is taken as the heating time t of the water flowing out of the heat exchanger 13.

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

The quantity W _P1 estimated here is a numerical value as the average quantity W in the heating time t. When the quantity of hot water supply W is sequentially changed, the quantity W is measured at each time point. It can't be represented.

In addition, when the quantity estimator 32 multiplies the stored and stored heating amount output information ΔQ sequentially from the new information, the effective heating time t is obtained only when the quantity is equal to the total heating amount Q _T. will be. Therefore, for example, at the beginning of hot water supply, even if it tries to multiply the heating quantity output information ΔQ until it becomes equal to the total heating amount Q _T , the estimated quantity W _P1 may not be retroactively before the start of hot water supply. Much larger than W). When this state is displayed, it is as shown in FIG. In FIG. 6, for example, the solid line C represents a large flow rate, and the solid line D represents a small amount, respectively.

Here, the quantity W _{P1 based} on the estimation of the quantity estimating unit 32, which represents a valid quantity Wc and Wd as a substitute for the actual quantity W, respectively, is shown after the start of hot water supply, respectively, at time tc. , Time td elapses. For this reason, the appropriate heating amount Q cannot be determined by the temperature control based on the quantity _WP1 until the time td and the time td respectively pass from the start of hot water supply.

Thus, in the present embodiment, the heat exchanger 13 is provided by the initial quantity estimating unit 33 as the quantity estimating means of the present invention instead of the quantity W ₁ estimated by the quantity estimating unit 32 described above only for the hot water heater. Estimate the quantity (W _P2 ) passing through).

That is, the tapping temperature Tout after the start of the hot water supply is represented by a change in accordance with the quantity W as shown in FIG. 7, for example, in the case of a large quantity, rises relatively quickly as indicated by the solid line E. As shown by the solid line F, the rate of increase is slow compared to the case of logarithmic quantities.

The initial quantity estimating section 33 estimates the quantity W based on the difference in the amount of time given by the heat exchanger 13 with the amount of heat given as a change in the tapping temperature Tout depending on the quantity W passing therethrough. Then, the elapsed time tm until the predetermined amount of heat due to heating is detected by the timekeeping section 33a, and the quantity W is estimated.

Here, a given amount of heat is given, and the multiplication value P (integral value with respect to time to detection temperature T) which multiplied the temperature rise (triangle | delta) of detection temperature T with the start of hot water supply is calculated | required, this is multiplied by the value (P) reveals the elapsed time (tm) to the multiplication when a predetermined value (P _o).

The predetermined integrated value P _o represents a constant amount of heat given to the heat exchanger 13 at the same time as the commencement of combustion. In FIG. 7, for example, in the case of a large quantity, the area S up to the time te is shown. _It is expressed as the amount of heat equivalent to ₁ ), and in the case of a small amount, it is expressed as the amount of heat corresponding to the area S ₂ until the time tf, and in particular, the quantity of water actually passing through the heat exchanger 13 here. In order to be able to detect the difference of (W) clearly, the value corresponded to the heating amount of a comparatively short time after the start of combustion.

In response to this revealed elapsed time tm, the quantity W _P2 is estimated as shown in FIG.

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

Incidentally, the time tc, td in FIG. 7 represents the same time as the time tc, td in FIG.

Therefore, for reference, each time (te, tf) of ending the time in each quantity in FIG. 7 represents the same time as the time (te, tf) in FIG. As described above, it is understood that these times te and tf are the time until the quantity W _P1 estimated by the quantity estimating unit 32 represents a certain quantity value Wx.

The temperature control unit 34 includes the target temperature Test set by the controller 40, the tapping temperature Tout detected by the tapping temperature thermistor 25, and the inlet temperature Tin estimated by the inlet temperature estimating unit 31. , The quantity of heating Q is determined from the quantities W _P1 and W _P2 estimated by the quantity estimating unit 32 and the initial quantity estimating unit 33, respectively.

Here, immediately after the start of the hot water supply, the start amount of water Ws of the water flow switch 19 is 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 ( Based on the test), determine the heating amount (Q).

Then, when the multiplication value is a predetermined multiplication value (P _o) determining the heat quantity (W ₂₎ estimated by the initial quantity estimation unit 33, a quantity (W) amount (Q), and quantity (W _P2 When the time determined based on C) elapses, the quantity of heat W _P1 estimated by the quantity estimating unit 32 is determined as the quantity W, and the heating amount Q is determined.

Moreover, when the detection temperature T of the tapping temperature thermistor 25 rises to a fixed temperature, the feedback control will be performed based on the detection temperature T. FIG.

By this feedback control In setting the quantity can (W _P1) of the feedback control system time constant based on the estimated by the number estimation section 32 of the above-described each time to performs a stable temperature control, and prevent the hunting, etc. occur . 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 set as the heating amount output information ΔQ, and is sequentially stored in the heating amount storage unit 34 described above every predetermined unit time Δt.

The drive part 35 drives control of the blower 12 and the control proportional valve 23 based on the heating amount Q of the temperature control part 34. As shown in FIG. 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, in the control device 30, in order not to exceed the heating capacity of the water supply amount, the amount of opening of the electric water quantity control device 18 is adjusted based on the detection temperature T of the tapping temperature thermistor 25 to limit the passage flow rate. .

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, with reference to FIG. 9, the temperature control in the gas-fired hot water heater 1 of the present embodiment having the above configuration will be described with reference to the estimation of the amount of water W. FIG.

When the user opens the hot water supply tank (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 the hot water supply is detected by the water flow switch 19 (YES in step 11), the ignition control is performed in a predetermined sequence to start combustion, and at the same time, the time-keeping time tm is started by the timekeeping section 33a. (Step 12). At this time, only when the tapping temperature Tout is not defended, 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. . Moreover, the temperature rise (DELTA) T for every predetermined unit time (DELTA) t of the detection temperature T of the tapping temperature thermistor 25 is multiplied, and the multiplication value P is calculated (step 13).

Multiplication value (P) a quantity based on a predetermined multiplication value (P _o) is above (step 14 YES in), time counting by (33a) revealed the end (step 15), the timing the elapsed time (tm) ( W _p2 ) is estimated (step 16), and the initial time tp is set in two quantities W _P2 (step 17).

When the initial time tp elapses (step 18), control by the quantity W _P1 estimated by the quantity estimating unit 32 is started (step 19), and then the amount of heating by the quantity W _P1 . (Q) is determined.

Since the quantity W _P1 obtained here is used as a time constant in the feedback control, when the tapping temperature changes due to a flow rate change, for example, the heating amount Q is corrected by the time constant in response to the flow rate change. As a result, hunting and the like due to the correction of the heating amount are hard to occur.

If hot water supply is stopped and hot water supply is stopped (YES in step 20), combustion stops.

As described above, according to this embodiment, since the quantity of water is estimated at the beginning of the hot water supply, an appropriate amount of heating is determined. In particular, the higher the quantity, the faster the temperature control is started based on the estimated quantity, so that the increase in tapping temperature is improved compared with the conventional case.

In the above embodiment, the quantity is estimated based on the time until the detection temperature indicates a predetermined change amount, but the quantity may be estimated based on the time until the detection temperature rises (indicating a change).

In this embodiment, only the hot water thermistor is provided as the sensor, and since the sensor is not provided at the inlet of the heat exchanger, the structure of the hot water heater is simplified, the manufacturing process is simplified, and simple feed back control is achieved. While having a structure equivalent to that of the hot water heater, a tapping temperature characteristic close to a very stable feed forward control is obtained.

Although the gas hot water heater using gas as a fuel was shown in the above Example, the hot water heater by other fuel, such as petroleum, may be sufficient. The heating source is not limited to the burner, and may be other heating means such as electric heating.

Claims (2)

When a hot water supply is detected by the water flow detection means which detects the inflow of water to a heat exchanger, heating of the said heat exchanger by a heating means is started, and it is based on the temperature information detected by the temperature sensor installed in the outflow part of the heat exchanger. A temperature control device of a hot water heater for controlling the amount of heating of the heating means, comprising: time means for counting the elapsed time after the start of the hot water supply, and a flow rate estimating means for estimating the flow rate of the water passing through the heat exchanger; Is estimating the flow rate on the basis of the time from when the hot water supply is started until the detection temperature of the temperature sensor shows a predetermined change. The temperature control device of the hot water heater according to claim 1, wherein the flow rate estimating means estimates the flow rate based on a time until an integrated value of the change in the detection temperature of the temperature sensor becomes a predetermined value.

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