JPH0587407A - Control method for hot water storage type hot water feeder - Google Patents

Abstract

PURPOSE:To enable execution of accurate control without using an inflow water temperature sensor by a method wherein after a feed hot water temperature is increased to a value approximately equal to a set temperature, ON-OFF combustion is carried out by means of the given number of hot water feeders, and an inflow water temperature being an assumed value is coected based on a deviation in a feed hot water temperature at a point of time when the feed of hot water is stabilized. CONSTITUTION:In a hot water storage type hot water feeder, a controller 5 to inputs detecting values Q and TH from an inflow water flow rate sensor 3 and a feed hot water temperature sensor 4 and information on a feed hot water set temperature TS by a remote controller 6 is provided. In the controller, the necessary number G of hot water feeders is computed from the feed hot water set temperature TS, the inflow water flow rate Q, and a preassumed inflow water temperature TC. Feedforward control is made on ON-OFF combustion of a burner so that the number of hot water feeders is adjusted to a value G. A difference DELTAT1 between the feed hot water set temperature TS and the feed hot water temperature TH is added to an assumed inflow water temperature TC to correct the assumed inflow water temperature TC. From the assumed inflow water temperature TC after correction, the necessary number of hot water feeders is re-computed to cause feedforward control of ON-OFF combustion of a burner.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot water storage type water heater control method.

[0002]

2. Description of the Related Art In a conventional hot water storage type water heater, a hot water temperature sensor attached to a hot water storage can detects the hot water temperature to perform feedback control.
Described in. That is, conventionally, the combustion off temperature T _OFF is set as the hot water discharge set temperature T _S , and the combustion on temperature T _ON is set as the hot water discharge set temperature T _S.
The burner was turned on and off at a constant temperature T _DF lower than _S.

[0003]

However, in the above-mentioned conventional hot water storage water heater, in the simple feedback (FB) control by turning on and off the combustion, the average hot water temperature exceeds the hot water set temperature T _S when the amount of water used increases. When the amount of water used decreases, the average hot water temperature shifts higher than the hot water set temperature T _S (offset occurs), or the hot water temperature fluctuates in a long cycle (the differential increases). there were. Further, although it is easily affected by the incoming water temperature, there is a problem that the variation in the hot water temperature (differential) becomes large due to the difference between the set outgoing hot water temperature and the incoming hot water temperature because the incoming water temperature is an unknown number.

Therefore, the present invention solves the above-mentioned drawbacks of the conventional hot water storage type water heater control method, and can reduce the offset of hot water discharge and the differential (fluctuation of hot water) in the vicinity of the hot water set temperature. Even if there is no temperature sensor, the deviation of the hot water temperature due to changes in the hot water temperature can be corrected to obtain a good hot water temperature, and the temperature of the hot water storage type water heater can be smoothly increased at the start of the cold start. The purpose is to provide a method.

[0005]

In order to achieve the above object, a method of controlling a hot water storage type hot water supply apparatus according to the present invention is a burner capable of switching at least heating capacity between continuous combustion and on-off combustion, a water flow rate sensor, and hot water discharge. A method for controlling a hot water storage type water heater having a temperature sensor, wherein a required hot water supply number G is calculated from a hot water output set temperature T _S , a water input flow rate Q, and an assumed water input temperature T _C, and the hot water output number G To control the on / off combustion of the burner so as to achieve the above, and the hot water discharge set temperature T at the time when the hot water discharge by this is stabilized.
The difference ΔT ₁ between _S and the tap water temperature T _H is defined as the assumed water inlet temperature T _C.
In addition to the above, the first feature is that the step of correcting the assumed inlet water temperature T _C , recalculating the required hot water outlet number G, and feed-forward controlling the burner on / off combustion again is repeated. In addition to the first feature, the hot water storage type water heater control method of the present invention performs strong combustion by continuous combustion while the hot water discharge temperature T _C is lower than a constant temperature ΔT below the hot water discharge set temperature T _S. Is the second feature.

[0006]

According to the first feature described above, once the hot water outlet temperature T _H is once near the hot water outlet set temperature T _S , the amount of incoming water is the number of hot water required to reach the hot water outlet set temperature. Since the on-off combustion is performed, it is possible to obtain the tapping characteristic in which the temperature fluctuation (the differential) of the tapping temperature T _H with respect to the tapping set temperature T _S is small. In addition, the inlet temperature T _C which is an assumed value
Is corrected to an accurate value by adding the difference ΔT ₁ between the hot water discharge set temperature T _S and the hot water discharge temperature T _H at the time when the hot water discharge is stable. Close to set temperature T _S (less offset)
Accurate tap water can be performed. According to the second feature, the strength by continuous combustion in the case of tapping the set temperature T _S against the hot water temperature T _H is considerably lower temperature (when lower beyond a predetermined temperature ΔT than tapping the set temperature T _S) combustion Therefore, in the case of cold start (when boiling the can body from water), the heating power is large and the rising of the hot water is improved.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the embodiments shown in the drawings. 1 is an overall schematic configuration diagram showing an example of a hot water storage type hot water supply device, FIG. 2 is a control block diagram of the hot water storage type hot water supply device, FIG. 3 is a diagram illustrating an example of a control method, and FIG. 4 is a flowchart of an example of the control method. is there.

In FIG. 1, 1 is a hot water storage canister and 2 is a burner. The burner 2 can perform on-off combustion at various on-off ratios and on-off cycles in addition to continuous combustion. Reference numeral 3 is an incoming water flow rate sensor, and 4 is a hot water outlet temperature sensor, which detects the hot water temperature in the hot water storage can body 1. Reference numeral 5 is a controller, and 6 is a remote controller. Further, in FIG. 2, the controller 5 has a control unit 8 having a built-in microcomputer, an input unit 7, and an output unit 9, and the input water flow rate Q information from the water flow rate sensor 3 is input to the input unit 7, hot water temperature T _H information from the hot water temperature sensor 4 is input, and tapping the set temperature T _S from the tapping temperature setting unit 14 of the remote controller 6 is input. Further, the output section 9 has a capacity switching device 10 for the burner 2 and a fuel (petroleum).
An electromagnetic pump 11 for supplying air, an ignition device 12, and a blower fan 13 are connected. Further, the remote controller 6 is provided with a display section 15 for indicating the driving state.

An example of the control method of the present invention will be described with reference to FIGS. 3 and 4. First, since this hot water storage type water heater does not have an incoming water temperature sensor, it is necessary to assume the incoming water temperature T _C. An initial value is appropriately given to the incoming water temperature T _C when the power is turned on. In the case of a cold start, when the operation is started, first, while the hot water outlet temperature T _H is lower than a temperature lower than the hot water outlet set temperature T _S by a constant temperature ΔT (in the case of NO at step 51).
Performs continuous combustion with the maximum input regardless of the incoming water flow rate and incoming water temperature (step 52). And the hot water temperature T _H
Is a certain temperature ΔT lower than the set hot water temperature T _S (T
_{When H} ≧ T _S −ΔT) (YES in step 51)
, Incoming water flow rate Q and outlet hot water set temperature T _S and assumed incoming water temperature T _C
From the above, the burner is on-off combusted with the combustion heat amount corresponding to the required hot water number G calculated by the following equation 1. The amount of heat of combustion for heating 1 liter at 25 ° C. for 1 minute is No. 1 of hot water.
Further, the constant temperature ΔT is experimentally obtained in advance, for example, in the range of several degrees to several tens of degrees depending on the heating capacity of the water heater. (T _S −T _C ) × Q / 25 = G ... Formula 1

In the equation 1, the assumed inlet water temperature T _C is the value that is finally corrected and stored in the previous operation at the start of the operation. Therefore, the assumed water inlet temperature T _C does not always match the actual water inlet temperature at the time of this operation, and therefore, even when the hot water temperature stabilizes (becomes a steady state), the hot water outlet temperature T _H is the set hot water temperature. It does not always match T _S. Therefore, after the hot water outlet temperature T _H has risen to a temperature lower than the hot water outlet set temperature T _S by a constant temperature ΔT, the hot water outlet temperature T _H is set at the set hot water temperature T _S each time a certain sampling time elapses (UP) (step 53).
Is monitored (step 54), and if there is a difference, the difference between the hot water outlet set temperature T _S and the hot water outlet temperature T _H (ΔT
₁ = T _S −T _H ) is added to the original assumed inlet temperature T _C and corrected to obtain a new assumed inlet temperature T _C (step 55). Then, the corrected new assumed inlet water temperature T _C is stored in the controller 8 and the required outlet water number G is calculated using the new assumed inlet water temperature T _C (step 56), and the feed-forward control is performed at the corresponding on / off ratio. On-off combustion is performed by (step 57). In this case, the on / off ratio can be obtained from the ratio between the calculated required hot water outlet number G and the heating capacity (combustion heat quantity) during continuous combustion of the burner of the water heater.
In addition, how long the time of one cycle of on-off combustion is set is
Since there is a preferable cycle time depending on the number of hot water discharged and the flow rate of incoming water, a cycle for each combination of the number of hot water discharged and the flow rate of incoming water is obtained in advance and stored in the controller 8 as a table.

In the above-described embodiment, in the cold start as shown in FIG. 3, continuous combustion is performed in the initial stage of operation, so that the rising hot water temperature T _H rises smoothly and quickly. Further, when the outlet heated water temperature is in a steady state, the outlet heated water temperature T _H is monitored at every constant sampling time, the assumed inlet water temperature T _C is corrected, and on / off combustion is performed under new feedforward conditions. Even if the actual incoming water temperature is not obtained, it is possible to surely adjust the outgoing hot water temperature T _H to the outgoing hot water setting temperature T _S by learning by itself. In addition, it can easily cope with seasonal changes.

[0012]

According to the control method of the hot water storage type hot water supply device of the present invention, the present invention has the hot water required to reach the hot water discharge set temperature. by on-off combustion is made in issue number, after the hot water temperature T _H is once turned around tapping the set temperature T _S is the temperature variation of the hot water temperature T _H for hot water set temperature T _S (Tiffa Ren interstitial)
It is possible to obtain a small hot water discharge characteristic. Further, since the assumed temperature of incoming water T _C is corrected to an accurate value by adding the difference ΔT ₁ between the set temperature T _S of outgoing hot water and the temperature of outgoing hot water T _H at the time when the outgoing hot water becomes stable, Even if there is no water temperature sensor, it is possible to perform accurate hot water discharge close to the hot water set temperature T _S (with a small offset). In addition, it is possible to sufficiently cope with changes in the incoming water temperature due to seasonal fluctuations. According to the control method of the hot water storage type water heater according to claim 2, hot water set temperature T if _S against tapping temperature T _H is considerably lower temperature (hot water set temperature T is lower beyond a predetermined temperature ΔT than _S ) Because strong combustion is performed by continuous combustion,
In the case of cold start (when boiling the can from water), the heating power is large and the rising of the hot water can be improved.

[Brief description of drawings]

FIG. 1 is an overall schematic configuration diagram showing an example of a hot water storage type water heater.

FIG. 2 is a control block diagram of a hot water storage type water heater.

FIG. 3 is a diagram illustrating an example of a control method.

FIG. 4 is a flowchart of an example of a control method.

FIG. 5 is a diagram illustrating a conventional example.

[Explanation of symbols]

 1 Hot water storage can 2 Burner 3 Water input sensor 4 Hot water temperature sensor 5 Controller 6 Remote control

Claims (2)

[Claims] And 1. A burner least capable switching the heating capacity due to continuous combustion and off combustion, the incoming water flow sensor, a control method of the hot water storage type water heater and a hot water temperature sensor, a hot water set temperature T _S water inlet A step of calculating a required hot water outlet number G from the flow rate Q and a presumed incoming water temperature T _C, and performing feed forward control of the on / off combustion of the burner so that the hot water outlet number G is obtained, The assumed inlet water temperature T is obtained by adding the difference ΔT ₁ between the outlet heated water set temperature T _S and the outlet heated water temperature T _H to the assumed inlet water temperature T _C.
A method for controlling a hot water supply type hot water supply apparatus, which comprises repeating the step of correcting _C , recalculating the required hot water outlet number G, and feed-forward controlling the on / off combustion of the burner again. 2. The hot water storage water heater control method according to claim 1, wherein strong combustion by continuous combustion is performed while the hot water outlet temperature T _C is lower than a constant temperature ΔT below the hot water outlet set temperature T _S.