JP2000161774A - Composite type hot-water supplier provided with temperature retaining function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control method of temperature retaining operation, which is provided with the effect of temperature retaining operation even under an operation except hot-water supplying function while securing the durability of a burner or the like and safety. SOLUTION: When a function except hot-water supply is operated during temperature retaining operation, a hot-water supplier is controlled so that temperature retaining combustion is started when a water temperature in a hot-water supplying heat exchanger is lowered by a predetermined value or more, however, when the function except hot-water supply is not operated, the temperature retaining combustion is started when the water temperature has become lower than the predetermined temperature. On the other hand, when the function except hot-water supply is operated during the temperature retaining operation, the water temperature is compared with the same in the heat exchanger after a holding period of time has elapsed and when the temperature is reduced by a value more than a predetermined value, the temperature retaining combustion is effected, however, when the water temperature is not lowered by a value more than the predetermined value, the control is shifted to the temperature retaining operation control under a condition that the function except hot-water supply is not operated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention makes it possible to keep the temperature of water in a heat exchanger at a proper level by performing a heat-retention operation during standby for hot water supply, and to prevent cold water from flowing out even at the beginning of hot water supply. The present invention relates to a water heater having a warming operation function, and more particularly to a combined water heater having either a bath function or a heating function or both in addition to the hot water supply function.

[0002]

2. Description of the Related Art Heretofore, even during standby for hot water supply, that is, even when hot water is not being supplied, a function of improving the hot water supply performance by appropriately heating the water in the appliance (hereinafter referred to as a heat retention operation function). ) Is provided with a warm water heater such as an instantaneous water heater. This is because the water heater keeps the temperature of the heat exchanger in the cold start and in the standby time of the hot water supply by using the warming operation function of the hot water supply. Is prevented from flowing out, and hot water at a set temperature is promptly provided to the user.

[0003] In this type of water heater with a heat-retaining operation function, when the temperature of the water in a pipe of a heat exchanger or the like becomes lower than a predetermined heat-retention combustion start temperature in a state where the heat-retention operation is turned on, the burner is used. The operation of heating the water in the pipe by performing the heat retention combustion for a short time and repeating the heat retention combustion when the water temperature falls below the temperature retention start temperature again is repeated. In such a heat-retaining operation, the burner is repeatedly burned. Therefore, an interval (stand-by time) in which the heat-retention combustion is not performed is set in advance in consideration of the durability of the components. Control is performed to perform a warming operation when the temperature exceeds the limit. In addition, when the cooling speed is high, the control of stopping the warming operation is performed by giving priority to the durability because the effect of the warming operation is low.

[0004]

By the way, in the combined type water heater, when other functions (bath or heating) are operated while the hot water supply is stopped, the exhaust gas generated by the combustion is prevented from flowing back to the hot water supply side. Is rotated (in some cases, one fan is shared), and the heat exchanger on the hot water supply side is cooled by the blower of the fan. In such a case, as in the conventional control method, even if the heat-retaining operation is performed after waiting until the temperature is cooled to a certain temperature, the cooling rate is too fast and the effect of the heat-retaining operation does not appear. Control was not performed.

Therefore, the present invention solves the problem of the warming operation in the above-mentioned combined type water heater, has the effect of the warming operation even during operation other than the hot water supply function, and ensures the durability and safety of the burner and the like. An object of the present invention is to provide a method of controlling a warming operation.

[0006]

Means for Solving the Problems To solve the above-mentioned problems, a combined type water heater with a heat retaining operation function according to the present invention comprises:
An inlet pipe, a tapping pipe, a heat exchanger disposed between these pipes, a temperature sensor for detecting a water temperature in the heat exchanger, and a burner mechanism for heating. At least, even when not supplying hot water, a hot water supply function having a heat retaining operation function of performing a heat retaining operation by burning the burner mechanism, and either a bath function or a heating function other than the hot water supply function, or both. In the combined water heater provided, when a function other than hot water supply is operating during the warm-up operation, when the temperature detected by the temperature sensor drops by a predetermined value or more, the warm-up combustion is started, When a function other than hot water supply is not operating, control is performed such that warm combustion is started when the temperature detected by the temperature sensor is equal to or lower than a predetermined temperature. If a function other than hot water supply is operating during the warm-up operation, a standby time is provided after the warm-up combustion, and the water temperature in the heat exchanger at the start of the warm-up combustion is detected by the temperature sensor and sent to the control unit. The stored temperature is compared with the water temperature in the heat exchanger after the elapse of the standby time, and if there is a temperature drop equal to or more than a predetermined value, warm combustion is performed. Even if the operation is being performed, the process shifts to the warming operation control when the function other than the hot water supply is not operating.

[0007]

Embodiments of the present invention will be described with reference to the drawings. 2. Description of the Related Art In recent years, there has been provided a combined type hot water supply device provided with a circulation circuit for circulating hot and cold water in a bath for hot water reheating and a circulation circuit for hot water for hot water heating. Here, FIG. 1 shows an example of a combined type water heater provided with such a circulation circuit.

The combined type water heater shown in FIG. 1 includes a hot water supply circuit A, a heating circuit B, a bath circuit C, and a drop circuit D as main parts, and these circuits provide hot water supply, heating, and bath water. Functions such as tensioning and reheating are realized.

More specifically, the hot water supply circuit A includes a hot water supply heat exchanger 14 heated by the gas burner 4,
On the water inlet side (water supply circuit side) of the hot water supply heat exchanger 14, an incoming water temperature sensor 12 for detecting the incoming water temperature and an incoming water amount sensor 13 for detecting the amount of incoming water are provided. A heat exchange temperature sensor 15 for detecting the temperature of hot water from the water heater 14, a water amount servo valve 1 for limiting the amount of hot water, and a hot water temperature sensor 16 for detecting the temperature of hot water to the outside of the water heater main body are provided. A bypass path is provided between the water inlet side and the hot water outlet side for short-circuit connection by bypassing the hot water supply heat exchanger 14, and a bypass valve 11 for limiting the flow rate of the bypass path is provided on the bypass path. .

The heating circuit B includes a heating circulation pump 31, a heating heat exchanger 22 heated by a gas burner 20, and a heating temperature sensor 2 for detecting the temperature of the heating water from the heating heat exchanger 22.
3. An expansion tank 21 for always maintaining a constant water volume, a bath heater 24 for bath reheating, a bath heat valve 32, and a bypass 35 are provided. The expansion tank 21 is provided with a water level electrode 33 for detecting a water level, one end of a water supply pipe 36 and one end of an overflow pipe 34 are connected, and the other end of the water supply pipe 36 is connected to a water inlet side of the hot water supply circuit A. At the same time, the other end of the overflow pipe 34 is open to the atmosphere. Further, a rehydration valve 30 is provided in the middle of the rehydration pipe 36.

The bath circuit C includes a bath heater 2 in the circuit.
4, a pressure sensor 5 for detecting the water level of the bathtub, a bath circulation pump 3, a water flow switch 6 for detecting the presence or absence of bathtub water, and a bath temperature sensor 25 for detecting the temperature of the bathtub water are provided. . Although the configuration in which the bath heater 24 is provided is shown in the illustrated example, a bath heat exchanger may be provided in the bath circuit C instead of the bath heater 24 and heating may be performed by a gas burner.

The drop circuit D is for connecting the hot water supply circuit A and the bath circuit C to drop hot water from the hot water supply circuit A into the bathtub through the bath circuit C.
Vacuum breaker 17, drop valve 2, drop water sensor 1
0 and a check valve 18 are provided.

In the combined water heater shown in FIG. 1, when performing additional heating operation or heating operation of the bath, the gas burner 20 is burned to heat the heating water by the heating heat exchanger 22, and the heating water and the bath water are heated. The heat is exchanged by the bath heater 24 to perform additional heating of the bath, or the heating water is circulated to a heating circuit outside the device as it is, and the room is heated by a radiator or the like. Here, in order to burn the gas burner 20, the heating fan 8 is rotated to blow combustion air to the gas burner 20.

Although the combustion exhaust gas from the gas burner 20 is discharged outside the device, it may rarely flow back into the device from the outlet on the hot water supply side due to an adverse wind or the like. The hot-water supply fan 7 is rotated to blow air.

FIG. 3 shows an example of a conventional heat retaining operation in the above case. The graph shown by the solid line in FIG. 3 shows the temperature of the hot water supply heat exchanger during heating and combustion, and the graph shown by the dotted line shows the temperature of the hot water supply heat exchanger when there is no heating combustion. In the case of no heating combustion, since the cooling rate of the hot water supply heat exchanger temperature is slow, if the heat exchange combustion is performed when the heat exchanger temperature T reaches the heat retention start temperature T1, the heat exchanger can be operated even after the standby time has elapsed. The temperature T is higher than T1, and the water temperature in the heat exchanger can be maintained at an appropriate temperature by repeating the insulated combustion for a short time. However, if there is heating combustion, the heat exchanger is rapidly cooled by the blowing of the hot water supply fan, and the heat exchanger temperature T is effective during the standby time even after performing the warming combustion after reaching the warming start temperature T1. Since the temperature was lower than the temperature T2, a sufficient heat retaining operation could not be performed.

The following two means can be considered to solve such a problem. One is to increase the warming combustion time, and the other is to shorten the waiting time between the warming combustions. However, if the warming combustion time is lengthened, the temperature rises sharply because the combustion takes place in a situation where the water on the hot water supply side is stopped, and the heat exchanger is damaged due to the pressure rise due to local boiling, There is a danger that hot water will flow out when hot water is reapplied. Further, if the standby time is shortened, the number of times of combustion increases, which may adversely affect the durability of the component. FIG. 4 shows an example of the heat retention operation when the standby time is shortened.

The warming operation control according to the present invention will be described with reference to a flowchart shown in FIG. First, the warming operation is started (the warming operation switch is turned on) in step S1, and when hot water supply combustion is stopped in step S2, the water temperature in the heat exchanger is detected by the heat exchange temperature sensor 15 and the temperature at this time is converted to heat. It is stored in the control unit as the exchanger initial temperature T0 (step S3).

In step S4, it is determined whether or not heating combustion is being performed. If heating combustion is not being performed, the process proceeds to step S12, which is the same heat-retention operation control as that of the related art. In Step S12, if the heat exchange temperature T is equal to or lower than the heat retention start temperature T1 (for example, 45 ° C.), Step S13
Otherwise, the process returns to step S4.

In step S13, a predetermined short-time warm combustion (for example, 5 seconds) is performed to appropriately raise the temperature of the heat exchanger, and in step S14, operation is waited for a predetermined standby time (for example, 5 minutes). Then, the process proceeds to step S15. In step S15, the heat exchanger temperature T is detected, and if the temperature is equal to or lower than a predetermined heat retention effective temperature T2 (for example, 35 ° C.),
The process proceeds to step S16 to end the warming operation. In this case, if there is a sudden drop in temperature during the standby time, the effect cannot be expected even if the warming operation is continued, so that the warming operation is ended with priority given to the durability of the appliance. Step S1
If the heat exchanger temperature T is higher than the heat retention effective temperature T2 at 5,
It is determined that the warming operation is effective, and the process returns to step S4 to continue the warming operation.

If heating combustion is being performed in step S4, the process proceeds to step S5. In step S5,
When the heat exchanger temperature T drops by a predetermined temperature deviation ΔT (for example, 10 ° C.) from the heat exchanger initial temperature T0, the process proceeds to step S6, and otherwise returns to step S4. In step S6, the heat exchanger temperature T at this time is stored in the control unit as the next warming start temperature Ton, and the process proceeds to warming combustion in step S7. The warm combustion at this time is the same as the warm combustion performed in step S13. The insulated combustion time varies depending on the size of the appliance, the amount of water retained, and the like, and a short-time combustion without danger such as local boiling, pressure rise, and hot water tapping is determined by experiments.

In step S8, as in step S14, the operation waits for a predetermined time. In step S9, it is determined whether or not heating combustion is continued. If heating combustion is completed, the process proceeds to step S12. . If the heating combustion is continued, the process proceeds to step S10, and the process proceeds to step S10.
At 10, if the heat exchanger temperature T is equal to or lower than the next heat retention start temperature Ton, the process proceeds to step S11; otherwise, the process proceeds to step S12. It is determined whether the temperature is equal to or lower than the next heat retention start temperature Ton by comparing the temperature rise due to heat retention combustion and the temperature drop during the standby time, and if it is determined that the rise is larger, there is no problem with the conventional control. This is for shifting to the conventional control.

In step S11, similarly to step S15, the heat exchanger temperature T is detected, and the predetermined heat-retention effective temperature T2
If it is not more than (for example, 35 ° C.), the flow shifts to step S16 to end the warming operation. If the heat exchanger temperature T is higher than the heat keeping effective temperature T2 in step S11, the process returns to step S6, and the heat exchanger temperature at this time is stored in the control unit as the next heat keeping start temperature Ton, and the heat keeping operation is repeated.

FIG. 5 shows an example of the warming operation by the above warming operation control. It can be seen that the heat retention effect continues for a long time even during the heating combustion as compared with the operation example of FIG. FIG. 4
As compared with the operation example of Example 1, the number of times of the heat-retention combustion is reduced, and the durability is also considered. In the warming operation control according to the present invention, the warming operation effect is continued for about 30 minutes or more even during the heating combustion, and the continuous burning time of the heating combustion is about 5 minutes in the additional heating operation of the bath and about 5 minutes at the start of the heating operation. Considering that it is 30 minutes (after that, intermittent combustion), the heat retaining operation control according to the present invention has a sufficient effect on its practicality.

[0024]

According to the heat retention control of the combined water heater according to the present invention, when a function other than hot water supply is operating during the heat retention operation, the heat exchange temperature sensor is controlled. When the detected temperature drops by a predetermined value (initial temperature deviation ΔT) or more, the heat-retention combustion is started, and when a function other than hot water supply is not operating, the detected temperature of the heat exchange temperature sensor becomes the predetermined temperature. (Heat-retention start temperature T1) By performing control to start heat-retention combustion when the temperature is detected below, even in a rapid cooling state in which the hot-water supply fan rotates due to the operation of other functions, the hot-water retention operation can be started from an early stage. Can be
There is an effect that the heat-retaining effect is continued within a sufficiently practical range, and when other functions are not operating, unnecessary heat-retaining operation is not performed, so that durability is secured. In the control according to the second aspect, the degree of cooling is determined by comparing the heat exchanger temperatures before and after the warming combustion and the standby time,
When the cooling rate is low, even if other functions are in operation, transition to the conventional heat retention operation control (control in a state where other functions are not operating) prevents the effect of unnecessary heat retention combustion. was gotten.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an example of a combined water heater according to the present invention.

FIG. 2 is a flowchart illustrating a warming operation control according to the present invention.

FIG. 3 is a diagram showing a change in a heat exchanger temperature by a conventional heat retaining operation control.

FIG. 4 is a diagram illustrating a change in a heat exchanger temperature by a heat retention operation control when a standby time is shortened.

FIG. 5 is a diagram showing a change in a heat exchanger temperature by the heat retention operation control of the present invention.

[Explanation of symbols]

 4 Hot water supply gas burner 7 Hot water supply fan 14 Hot water supply heat exchanger 15 Heat exchange temperature sensor 20 Heating gas burner 22 Heating heat exchanger 24 Bath heater T Heat exchanger temperature T0 Heat exchanger initial temperature T1 Heat retention start temperature T2 Heat retention effective temperature △ T Initial temperature Deviation Ton Next heat retention start temperature

Claims (2)

[Claims] 1. A water inlet pipe, a hot water pipe, a heat exchanger disposed between these pipes, a temperature sensor for detecting a temperature of water in the heat exchanger, and heating. A hot water supply function having a heat retaining operation function of burning the burner mechanism to perform a heat retaining operation even when the hot water supply is not performed, and one of a bath function and a heating function in addition to the hot water supply function. , Or in a combined type water heater equipped with both, if a function other than hot water is activated during the warm-up operation,
When the temperature detected by the temperature sensor drops by a predetermined value or more, warm combustion is started, and when a function other than hot water supply is not operating, the temperature detected by the temperature sensor is detected to be lower than a predetermined temperature. A combined water heater with a heat retention operation function, characterized in that control is sometimes performed to start heat retention combustion. 2. A water inlet pipe, a tap water pipe, a heat exchanger disposed between these pipes, a temperature sensor for detecting a water temperature in the heat exchanger, and a heater for heating. A hot water supply function having a heat retaining operation function of burning the burner mechanism to perform a heat retaining operation even when the hot water supply is not performed, and one of a bath function and a heating function in addition to the hot water supply function. , Or in a combined type water heater equipped with both, if a function other than hot water is activated during the warm-up operation,
A standby time is provided after the insulated combustion, and the water temperature in the heat exchanger at the start of the insulated combustion is detected by the temperature sensor, stored in the control unit, and compared with the water temperature in the heat exchanger after the elapse of the standby time. If there is a temperature drop of a predetermined value or more, warm insulation combustion is performed, and if there is no temperature drop of a predetermined value or more, even if functions other than hot water supply are operating, functions other than hot water supply are not operating. A combined type water heater with a warming operation function characterized by shifting to a warming operation control in the case.