JP2000227250A - Bath hot water supplying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately compute a remaining water amount through computing a quantity of heat, in a one-drum two-water passage system bath hot water supplying device to have a function to compute a remaining water quantity through a quantity of heat computing system. SOLUTION: In a controller 31 of a bath hot water supply device 1, a table is provided to indicate a relation between the temperature of hot water in a bath tub detected by a bath tub hot water temperature detecting sensor 21, the temperature of hot water in the water wall of a heat-exchanger 2 for hot water supply detected by a drum body thermistor 9, and bath capacity. When operation to compute a quantity of heat is started, the temperature of hot water in a bath tub during starting is detected, and the temperature of hot water in a bath tub and the temperature of hot water in the water wall are also detected during completion. Bath capacity during starting and bath capacity during completion are determined according to the respective hot water temperatures, and a remaining water amount is determined through computation of a quantity of heat by using an average value of two kinds of bath capacity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a bath water heater. In particular, the present invention relates to a one-can-two-drain hot-water storage type bath water heater in which a heat transfer tube for additional heating of hot water in a bathtub is accommodated in a water wall of a heat exchanger for hot water supply.

[0002]

2. Description of the Related Art A so-called hot water storage type hot water supply apparatus having a hot water storage section in a bath water supply apparatus is mainly a one-can-two-water-channel (one burner) type. In this method, the heat exchange part of the reheating circuit of the bathtub, that is, the heat transfer tube is placed in the water wall of the heat exchanger for hot water supply, and the heat exchange for hot water supply is performed by one burner while detecting the temperature of the hot water in the water wall. By heating the water in the water wall of the heat exchanger for hot water supply by heating the heater to make hot water of the set temperature, the circulating water in the bath tub flowing through the heat transfer tube of the reheating circuit in the water wall is indirectly heated. It is designed to be heated. In addition, in such a hot water storage type, the burner has a combustion capacity (combustion heat quantity).
It is common to use one with fixed and intermittent combustion control.

On the other hand, as a method for detecting the remaining amount of hot water in a bathtub, there is a method called a calorific value calculation method. This method is widely used for a two-can, two-channel (two-burner) type, and is a method for detecting the amount of residual water when there is residual water at or above the bath adapter level in the bathtub. The pre-heating temperature of the hot water in the bathtub is detected by circulating the hot water in the reheating circuit, and then the hot water in the bathtub is heated in the reheating circuit for a certain period of time. Detect the heating temperature. Since the combustion capacity (combustion heat amount) of the additional heating circuit is known in advance, the residual water amount in the bathtub can be thermodynamically calculated from the temperature difference between the heating temperature and the pre-heating temperature and the combustion time.

[0004] However, in the one-can-two-channel hot-water storage type bath water heater, the water in the water wall of the heat exchanger for hot water supply is heated by a single burner, and the water for indirect reheating in the water wall is indirectly heated. Since the hot tub circulating hot water flowing through the heat pipe is heated, the hot water in the water wall of the hot water supply heat exchanger is opened and the hot water tap is opened to discharge hot water during the additional heating for calorific value calculation. A part of it is taken away, the amount of heat supplied to the bathtub circulation hot water, that is, the bath capacity (hereinafter referred to as bath capacity) decreases, and even if the burner combustion capacity (combustion heat) is fixed, The amount of residual water in the bathtub cannot be thermodynamically calculated from the temperature difference between the pre-heating temperature and the combustion time. If the amount of heat deprived to the hot water supply side, that is, the hot water supply capacity (hereinafter, referred to as hot water supply capacity) can be calculated, the bath capacity can be calculated. However, in the case of the hot water storage type, the water supply sensor is generally provided in the hot water supply circuit. Not even this calculation.

[0005] Further, in the one-can-two-drain hot-water storage type bath water heater, even if the hot water is not used, if the temperature of the hot water in the bath tub, that is, the temperature of the hot water flowing into the heat transfer tube for additional heating changes,
Along with that, the amount of heat required to maintain the hot water in the water wall of the hot water supply heat exchanger at a constant temperature also changes, and the heat exchange efficiency also changes, so the burner's combustion capacity (combustion heat) also changes greatly. I do. (For example, when the hot water temperature is 40 ° C., the combustion capacity is reduced by 50% or more as compared with the case where the hot water temperature is 10 ° C.) Since the case where the hot water supply is not used is used here, the burnability (burning heat amount) of the burner is Point to.

When a burner having a variable combustion capacity (combustion heat quantity) is continuously burned, the quantity of heat given can be easily calculated by knowing the fuel consumption for a certain period of time. ) When using the fixed and intermittent combustion control type, it is necessary to lengthen the certain time in order to accurately detect the amount of heat given in a certain time,
Not realistic. Therefore, the residual water amount in the bathtub cannot be thermodynamically calculated from the temperature difference between the heating temperature and the pre-heating temperature and the combustion time. Therefore, a method has been adopted in which a pressure sensor is provided on the bath adapter to measure the amount of residual water in the bathtub, and the amount of residual water in the bathtub is measured by the output of the pressure sensor for the water level above the bath adapter.

However, in the method of disposing the pressure sensor on the bath adapter, it is necessary to take out the signal line of the pressure sensor from the bath adapter at the construction site and wire it inside the wall. Or, a lot of man-hours were required for repair work.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned technical problems, and an object of the present invention is to provide a can having a function of calculating a residual water amount by a calorific value calculation method. An object of the present invention is to make it possible to accurately calculate a residual water amount by a calorific value calculation in a two-channel hot water storage type bath water heater.

[0009]

According to a first aspect of the present invention, there is provided a bath water heater in which a heat exchanger for hot water supply is directly heated by a single burner, and is disposed in a water wall of the heat exchanger. In a bath water heater that indirectly heats a heat transfer tube for reheating with hot water in the water wall, the bath water supply device includes a temperature detecting unit for detecting a hot water temperature in the bathtub and a hot water temperature in the water wall, The bath capacity used for calculating the remaining water amount by the calorific value calculation method is obtained based on the hot water temperature in the bathtub and the hot water temperature in the water wall detected by the means.

[0010] Here, the residual water amount calculation of the calorific value calculation method is as follows.
In this method, the hot water remaining in the bathtub is heated for a predetermined time, and the remaining water amount is determined from the temperature difference between the hot water temperature before the start of the heating and the hot water temperature after the end of the heating and the amount of heat applied to the hot water in the bathtub during that time. Further, in order to determine the combustion capacity used for calculating the residual water amount by the calorific value calculation method, that is, the bath capacity, based on the temperature of the hot water in the bathtub, the relationship between the hot water temperature in the bathtub, the hot water temperature in the water wall of the hot water supply heat exchanger, and the bath capacity is determined in advance. Is stored in a storage device or the like. Here, the temperature of the hot water in the bathtub may be detected by a temperature sensor disposed in the middle of the circulation circuit, or directly detected by disposing a temperature sensor on a bath adapter of the bathtub. Any method may be used as long as the method can directly or indirectly detect the temperature of hot water in the bathtub. In the following description, the temperature of the hot water in the bathtub is referred to as a bath temperature. Although the detection value of the hot water temperature in the water wall of the hot water supply heat exchanger differs depending on the detection position, any position may be used as long as it can directly or indirectly detect the hot water temperature in the water wall. In the following description, this hot water temperature in the water wall is referred to as the can body temperature.

In the bath water heater of the present invention, the bath capacity used for calculating the remaining water amount is determined according to the bath temperature and the can body temperature. It is possible to use a bath water heater of a so-called one-can, two-channel hot-water storage system, in which the burner has a fixed burning capacity (combustion heat quantity) and has an intermittent combustion control. The amount of residual water in the bathtub can be accurately obtained.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic configuration diagram showing a one-can-two-channel hot-water storage type bath water heater 1 according to an embodiment of the present invention. The bath water heater 1 is of an oil type using oil as a fuel, and a burner 3 for burning oil is provided below the heat exchanger 2 for hot water supply. Is supplied, and intermittent combustion control is performed with a fixed combustion capacity (combustion heat quantity) so as to maintain the can body temperature detected by the can body thermistor 9 at a set temperature. A blower 6 for forcibly sending air for combustion is provided above the burner 3, and air, exhaust gas and the like forcedly blown from the blower 6 are discharged to the outside from an exhaust pipe 7. Further, a bathtub 28 is provided in the water wall of the heat exchanger 2 for hot water supply.
A heat transfer tube 8 which is a heat exchange unit for additional heating of the additional heating circuit 40 connected to the bus adapter 29 is provided.

The hot water supply path 30 includes a water supply path 10 connected to the water supply side of the hot water supply heat exchanger 2 and a water supply path 1 connected to the hot water supply side.
The water inlet 10 has a check valve 12 and a safety valve 13.
Is provided. When the hot water tap 16 provided at the pipe end of the hot water supply path 11 is opened, the water flowing through the hot water supply path 30 is heated by the hot water supply heat exchanger 2 heated by the burner 3, and is turned into hot water having a set temperature. Hot water is supplied from hot water tap 16.

The reheating circuit 40 includes a heat transfer tube 8 serving as a heat exchange unit for reheating, a return pipe 19 connected to the heat transfer tube 8, and a forward pipe 23. The return pipe 19 includes a circulation pump 20, a bathtub temperature detection. A sensor 21 and a water flow switch 22 are provided. However, when reheating the hot water in the bathtub 28,
After the circulation pump 20 is operated to confirm that there is hot water at or above the bus adapter level by the circulation determination, the circulation pump 20 is used to add the hot water to the heat exchanger tube 2 arranged in the water wall of the hot water supply heat exchanger 2 heated by the burner 3. The hot water circulating in the heating circuit 40 is heated, and when the temperature of the hot water in the bathtub 28 detected by the bathtub hot water temperature sensor 21 reaches the set temperature, the operation of the circulation pump 20 is stopped.

A dropping channel 41 branched from a pipe end portion of the tapping channel 11 is connected to the inlet channel 10 and the bypass channel 17 having the bypass flow rate adjusting valve 18 through the orifice 46 and a dropping on-off valve. 24, the pouring water amount sensor 25, and check valves 42 and 43, which are connected in the middle of the outgoing pipe 23 of the reheating circuit 40.
A bypass flow path 26 having a check valve 44 is provided between the return pipe 19 and the return pipe 19. When the hot water is dropped into the bathtub 28 to fill the bathtub 28 with water, the drop opening / closing valve 24 is opened, and the hot water supply heat exchanger 2 of the hot water supply path 30 is opened.
The hot water that has been heated in the hot water and that has flowed out of the hot water path 11
6, the flow rate is regulated, and while the temperature is detected by the water injection thermistor 27 arranged in the outgoing pipe 23 of the additional heating circuit 40, the opening degree of the bypass flow rate adjusting valve 18 provided in the bypass passage 17 is controlled to set the temperature. The hot water is poured into the reheating circuit 40, and the bypass flow path 2 having the going pipe 23 and the check valve 44 is provided.
The hot water is dropped into the bathtub 28 from the bus adapter 29 by the double transfer from the return pipe 19 through 6.

Next, a description will be given of the determination of the residual water amount by the calorific value calculation method in the bath water heater 1 of the one-can two-channel hot-water storage type. In the bath water heater 1, the temperature of the hot water returning from the bath tub 28 to the heat transfer tube 8 by the bath tub hot water temperature detection sensor 21 provided in the additional heating circuit 40, that is, the bath tub 2
8 is detected. When the hot water tap 16 is closed and the bath is used alone, the temperature of the hot water in the bath tub 28 detected by the bath hot water temperature detection sensor 21, that is, the bath temperature, and the water temperature from the burner 3 to the water wall of the heat exchanger 2 for hot water supply. For example, there is a correlation as shown in (a1) of FIG. 2 between the amount of heat given to the arranged heat transfer tubes 8, that is, the bath capacity. This correlation can be obtained experimentally. Therefore, the bath capacity is measured every time the bath temperature measured by the bathtub hot water temperature detection sensor 21 changes, for example, by 0.5 ° C., and the relationship between the bath temperature and the bath capacity is stored in a table format (or as a function). Is stored in the storage device. In this experimental example, the following equation was obtained as a function. W = −230T + 15600 formula Here, W indicates a standard bath capacity (Kcal / h), and T indicates a bath temperature (° C.). The standard bath capacity refers to the bath capacity when the bath is used alone with the hot-water tap 16 closed and the can body temperature is at the standard temperature (here, 70 ° C.).

When the hot water tap 16 is opened and hot water is discharged from the hot water tap, the can body temperature detected by the can body thermistor 9 decreases. By changing the amount of hot water from the hot water tap (for example, 6 l / m
In, 9 l / min), the relationship between bath temperature and bath capacity and the relationship between bath temperature and can body temperature were measured at each hot water supply, and these were shown in a graph as the relationship between bath temperature and bath capacity. (B1) and (C1) of FIG. 2 are obtained, and (b2) and (C2) of FIG.
The relationship of 2) was obtained. Similarly, (a2) shows hot water tap 16
Is the relationship between the bath temperature and the can body temperature in the closed state. This means that if the bath temperature and the can body temperature are measured, the bath capacity at that time can be determined without measuring the amount of hot water from the hot water tap and without knowing the fuel consumption. .

From these measurement results, the graph of FIG. 3 was derived, and when this was replaced with a function, an equation was obtained. C = 1-0.025 (S−U) where S is the standard can body temperature (° C.) (eg, 70 ° C.), U is the measured can body temperature (° C.), and C is the can body. The ratio of bath capacity to bath capacity when the temperature is the standard temperature.

Therefore, the actual bath capacity after the correction based on the can body temperature can be expressed by the following equation. P = W × C Expression where P is the corrected actual bath capacity (Kcal / h). Although the standard temperature is set to 70 ° C. here, the temperature is not limited to 70 ° C., and may be another temperature (for example, 80 ° C.).

When the operation for obtaining the residual water amount by the calorific value calculation is started, the bath temperature in the bathtub 28, that is, the bath temperature Ta is measured by the bathtub hot water temperature detection sensor 21, and the standard bath corresponding to the bath temperature Ta is measured. The capacity value Wa is calculated by the equation, and the ratio Ca to the bath capacity at the standard can body temperature at the can body temperature Ua is calculated by the equation. Also,
The corrected actual bath capacity Pa is calculated by the equation. Similarly, when the operation of the calorific value calculation is ended, the bathtub hot water temperature detection sensor 2
1, the temperature of the hot water in the bathtub 28, that is, the bath temperature Tb, is measured, and the value Wb of the standard bath capacity corresponding to the bath temperature Tb is calculated by an equation. The ratio Cb to the bath capacity is calculated. In addition, the corrected actual bath capacity Pb is calculated by the equation. Next, the average value P of the actual bath capacity Pa [kcal / hour] at the start of operation and the actual bath capacity Pb [kcal / hour] at the end of operation.
The residual water amount is determined by calorific value calculation using mean = (Pa + Pb) / 2. That is, assuming that the reheating operation time for calorific value calculation is S [hour], the remaining water amount K in the bathtub 28
[L] can be calculated by the following equation. K = (Pmean × S) / (Tb−Ta) = {(Pb + Pa) × S} / 2 (Tb−Ta) Equation

FIG. 4 shows the bathtub 2 in the calorific value calculation as described above.
FIG. 8 is a flowchart specifically showing a procedure for calculating the amount of residual water in 8 and then reheating the hot water in the bathtub 28. According to this procedure, when an automatic switch provided in a kitchen remote controller, a bathroom remote controller, or the like is turned on (S
1) A fixed amount Q1 (for example, 10 liters) of hot water or water is dropped from the tapping path 11 into the hot water dropping path 41 and the reheating circuit 4.
Bathtub 28 in both transports through the outgoing pipe 23 and return pipe 19
(S2). Next, the circulation pump 20 is operated, and the circulation is determined based on whether or not the water flow switch 22 is turned on (S3). Circulation determination is based on the fact that water remaining at a level higher than the bath adapter level is present in the bathtub 28 and the water flow switch 2
If 2 is turned on, it is determined as OK (YES),
There is only residual water below the bath adapter level in the bathtub 28,
Not OK when water flow switch 22 is off (NO)
Is determined.

If the circulation determination is not OK, there is only remaining water below the bath adapter level, and there is no danger that hot water will overflow from the bathtub 28 even if a sufficient amount of water is dropped, so a certain amount of hot water Q2 (for example, (10 liters) is dropped into the bathtub 28 from the tapping path 11 through the dropping path 41 and the outflow pipe 23 and the return pipe 19 of the additional heating circuit 40 by both transports (S4). Next, the normal reheating operation is performed to heat the hot water in the bathtub 28 to a set temperature (S12), and a warming operation for, for example, 4 hours is started (S13).

On the other hand, if the circulation judgment is OK (YES), there is residual water higher than the bath adapter level, and it is desired to drop hot water to about the set water level so as not to overflow the bathtub 28. The remaining water amount is obtained by calculation. When the calorific value calculation starts, the circulation pump 20 and the bathtub 28
By heating the hot-water supply heat exchanger 2 with the burner 3 while circulating the hot water in the additional heating circuit 40, the water in the water wall of the hot-water supply heat exchanger is heated to a set temperature of hot water. Then, the bath circulating water flowing in the heat transfer tube 8 of the reheating circuit 40 in the water wall is indirectly heated (S5). At the same time, at the start of the calorific value calculation, the bath temperature T
a, the can body temperature Ua is detected by the can body thermistor 9,
It is stored in the storage device of the controller (S6). When the reheating operation for a fixed time S is completed (S7), the bath temperature Tb at the end is detected by the bathtub hot water temperature detection sensor 21, and the can body temperature Ub at the end is detected by the can body thermistor 9, and stored in the storage device of the controller. It is stored (S8).

When the reheating operation for a predetermined time S for calorific value calculation is completed in this way, the bath temperature T at the start and at the end is set.
a, Tb and the can body temperatures Ua, Ub are read from the storage device, and the controller is used to start the bath temperature Ta, the actual bath capacity Pa corresponding to the can body temperature Ua, the end bath temperature Tb, and the can body temperature. The actual bath capacity Pb corresponding to Ub is read from the table, and the remaining water amount K is calculated by the above equation (S9).

When the remaining water amount K is obtained, the controller determines whether or not it is necessary to pour water into the bathtub 28 (S10). If it is necessary, the controller determines the remaining water amount K from the set water amount (water amount up to the set water level). After dropping the amount of hot water drawn into the bathtub 28 (S11), and as soon as it is determined that the remaining water amount K is close to the set water amount and pouring is not necessary, a normal reheating operation is performed to set the hot water in the bathtub 28. Heat up to temperature (S12),
For example, a warming operation for 4 hours is started (S13).

In this embodiment, the bath temperature and the can body temperature are detected at the start and end of the reheating operation for calorific value calculation, and the actual bath capacity according to the bath temperature and the can body temperature is used. The residual water amount can be obtained with high accuracy. Further, since the average value of the actual bath capacity at the start of the additional heating and the actual bath capacity at the end of the additional heating is used, the calculation accuracy of the residual water amount can be further improved by a simple calculation.

In the above embodiment, the bath temperature and the can body temperature are detected only at the start and end times. However, the bath temperature and the can body temperature are detected at regular time intervals, and the actual bath temperature changes at regular time intervals. The capacity may be obtained, and the values may be integrated to obtain an average value of the actual bath capacity. Alternatively, if the table has actual bath capacity values for each of a constant temperature (for example, 0.5 ° C.) of the bath temperature and the can body temperature, the time interval for each constant temperature is measured, and the time interval is determined. The product of the bath capacity value at that time may be integrated to obtain the average value of the actual bath capacity.

In the above embodiment, the circulation flow rate of the circulation pump 20 is not detected, but the circulation pump 20
2 and 3 for each circulating flow
Is obtained experimentally, and several types of data (for example, a circulation flow rate of 8 l / mi) are obtained in a table form or as a function
n from 10 to 17 l / min for each 1 l), and circulating flow sensor is arranged on the outgoing pipe 23 or the return pipe 19 of the additional heating circuit 40 to detect the circulating flow rate, and the actual bath at the circulating flow rate You may ask for abilities, in which case
Although the cost is increased, the remaining water amount can be obtained with higher accuracy.

The method of detecting the circulating flow rate is not limited to the method using a flow rate sensor, but may be simply obtained from the detected temperature difference between the bathtub hot water temperature detection sensor 21 and the water injection thermistor 27. In this case, the relationship between the detected temperature difference between the bathtub hot water temperature detection sensor 21 and the water injection thermistor 27 in the can body thermistor detection temperature stable state (for example, 70 ° C.) and the circulation flow rate is experimentally obtained by closing the hot water tap 16 in advance. In advance, keep it in a table format or as a function. In this method, the detection accuracy of the flow rate is inferior to the method using the flow sensor, but it is economical without increasing the cost.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a hot water storage type one-can two-channel water heater system according to an embodiment of the present invention.

FIG. 2 is a graph showing a relationship between bath temperature, bath capacity, and can body temperature.

FIG. 3 is a graph showing a relationship between a can body temperature difference and a bath capacity change rate.

FIG. 4 is a flowchart showing a procedure for reheating the hot water in the bathtub in the bath water heater of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bath hot water supply apparatus 2 Heat exchanger for hot water supply 3 Burner 9 Can body thermistor 11 Hot water outlet 20 Circulation pump 21 Bath water temperature detection sensor 22 Water flow switch 27 Water injection thermistor 28 Bath tub 30 Hot water supply path 31 Controller 40 Reheating circuit 41 Hot water drop-in path 50 Safety valve 51 Empty firing safety device 52 Strainer

Claims (1)

[Claims] 1. A heat exchanger for hot water supply is directly heated by one burner, and a heat transfer tube for additional heating disposed in a water wall of the heat exchanger is indirectly heated by hot water in the water wall. A hot water supply apparatus for electrically heating, comprising a temperature detecting means for detecting a hot water temperature in the bathtub and a hot water temperature in the water wall, and a hot water temperature in the bathtub detected by the temperature detecting means and a water temperature in the water wall. A bath water heater, wherein a bath capacity used for calculating a residual water amount by a calorific value calculation method is obtained based on a hot water temperature.