JP2017009215A - Auxiliary heat source machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an auxiliary heat source machine configured to start/stop a heating operation based upon a predicted hot water exiting temperature, calculated using a bypass ratio, a water entering temperature and a hot water exiting temperature, and a set temperature.SOLUTION: There is provided an auxiliary heat source machine 5 which re-heats hot water supplied from a hot water storage unit 2 and taps hot water of preset temperature, the auxiliary heat source machine comprising: a heating part 22, an inflow-side passage 21; a hot water outflow-side passage 23; a bypass passage 24 connecting the inflow-side passage and the hot water outflow-side passage; a bypass control valve 25; inflow temperature detecting means 28 of detecting a temperature of hot water running in the inflow-side passage; and hot water outflow temperature detecting means 28b of detecting a temperature of hot water flowing to the hot water outflow-side passage on a side upstream from a confluence part of the by-pass passage. A predicted hot water outflow temperature is calculated from a bypass ratio when the bypass control valve is fully opened, the detected inflow temperature, and the detected hot water outflow temperature, and a heating operation of the auxiliary heat source machine is started/stopped based upon the temperature difference between the set temperature and predicted hot water outflow temperature.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an auxiliary heat source apparatus, and more particularly to an auxiliary heat source apparatus that reheats hot water supplied from a hot water storage unit and outputs hot water at a set temperature.

  Conventionally, hot water storage hot water supply devices that store hot hot water and supply it to a desired hot water supply destination such as a hot water tap have been put to practical use. This type of hot water storage and hot water supply system includes a hot water storage tank for storing hot hot water, various valves and various passages such as a hot water mixing valve, a main heat source machine for heating hot water in the hot water storage tank, An auxiliary heat source machine for reheating when the temperature of hot water stored in the hot water storage tank is low, a control unit for controlling these main heat source machines, auxiliary heat source machines, and the like are provided.

  As said auxiliary heat source machine, a heating part, a water entrance side passage, a hot water side passage, a bypass passage bypassing the heating part, a bypass adjustment valve for adjusting the amount of water flowing in this bypass passage, and a heating part There is a case where a bypass type water heater provided with an incoming water temperature detecting means and a hot water temperature detecting means for the hot water from the heating section is employed (Patent Document 1).

  In the control unit, the combustion prohibition region in which combustion of the auxiliary heat source unit is prohibited and the combustion prohibition are canceled using the inlet temperature of the auxiliary heat source unit and the heating part outlet temperature (can temperature) of the auxiliary heat source unit as parameters. The map which preset the combustion prohibition cancellation | release area | region is stored. When the combustion prohibition condition is satisfied, the control unit outputs a combustion prohibition signal to the auxiliary heat source machine to stop combustion, and when the combustion prohibition release condition is satisfied, the control unit outputs a combustion prohibition cancellation signal to the auxiliary heat source apparatus to start combustion. .

  Since the pipe length from the hot water storage unit to the auxiliary heat source machine is wide (1.5 to 10m), there is a hot water supply assist mode as a hot water waiting improvement measure, and the pipe and auxiliary heat source machine from the hot water storage unit to the auxiliary heat source machine are cold. In this case, the auxiliary heat source machine is burned while discharging hot water at a set temperature from the hot water storage unit at the same time as hot water. Thereafter, the control unit monitors the incoming water temperature and can temperature of the auxiliary heat source unit, and when the combustion prohibition condition is satisfied, stops the combustion of the auxiliary heat source unit at an appropriate timing and switches from the backup hot water to the tank hot water.

  In this case, when the auxiliary heat source unit is installed at a location away from the hot water storage unit, the detection signal and control signal are delayed (time lag), and combustion start and stop operations are delayed in the auxiliary heat source unit. It is not easy to suppress the temperature to (set temperature ± 3 ° C.).

The control unit of the auxiliary heat source unit simply starts combustion and stops combustion based on the combustion prohibition release signal and combustion prohibition signal from the control unit, and the control unit of the auxiliary heat source unit determines whether combustion starts or stops. Such a system is not configured.
However, the control unit of the auxiliary heat source unit incorporates a control for autonomously stopping combustion when it is predicted that the tapping temperature will be (set temperature + 8 ° C.) or higher as a countermeasure in case of abnormality, In this control, the above (set temperature + 3 ° C.) is surely exceeded.

  In the hot water supply apparatus described in Patent Document 2, a bypass pipe that connects a water supply pipe that supplies water to the heat exchanger of the hot water supply section (heat source unit) and a hot water supply pipe that discharges water from the heat exchanger is provided, and flow control is performed on the bypass pipe. And a bypass ratio determining means for determining a water supply bypass ratio (ratio of the amount of water supplied to the heat exchanger and the amount of bypass water supplied to the bypass pipe) in the flow rate control means, and a hot water supply set temperature, a water supply temperature, and a bypass ratio. Based on the above, a technique for calculating the predicted hot water temperature discharged from the heat exchanger and controlling the bypass ratio so that the predicted hot water temperature becomes higher than the temperature at which the drain is generated in the heat exchanger is employed.

Japanese Patent No. 5058193 Japanese Patent No. 3628871

  The map for setting the combustion prohibition area and the combustion prohibition release area is set using the temperature of the water entering the auxiliary heat source unit and the temperature of the can at the outlet of the heat exchanger as parameters. In addition, it takes a great deal of labor to design the system, and the calculation process is increased because the calculation process is executed based on the map even in the actual control during the operation.

  The conventional auxiliary heat source unit is basically configured to start / stop combustion based on a command from the control unit, and a two-core communication line between the control unit and the control unit of the auxiliary heat source unit. However, it is difficult to improve accuracy because a signal delay occurs during communication, and it is desirable that the control unit of the auxiliary heat source unit can determine the start / stop of combustion.

  In the hot water supply apparatus of Patent Document 1, although the predicted hot water temperature discharged from the heat exchanger is calculated based on the hot water supply set temperature, the feed water temperature, and the bypass ratio, this predicted hot water temperature is used to control combustion start / stop of the heat source machine. It is not intended for use.

  An object of the present invention is to provide an auxiliary heat source apparatus that starts / stops a heating operation based on a predicted hot water temperature calculated using a bypass ratio, an incoming water temperature, and a hot water temperature, and a set temperature. .

  The auxiliary heat source device according to claim 1 is an auxiliary heat source device that is disposed in a hot water passage of the hot water storage unit, reheats hot water supplied from the hot water storage unit, and outputs hot water at a preset temperature, a heating unit, An inlet side passage, an outlet side passage, a bypass passage that bypasses the heating section and connects the inlet side passage and the outlet side passage, a bypass adjustment valve for adjusting the amount of water flowing in the bypass passage, and an inlet side passage In the auxiliary heat source machine comprising an incoming water temperature detecting means for detecting the temperature of hot water flowing in the hot water, and a hot water temperature detecting means for detecting the temperature of hot water flowing in the hot water outlet side passage upstream of the junction of the bypass passage, The predicted hot water temperature is calculated from the bypass ratio when fully opened, the incoming water temperature detected by the incoming water temperature detecting means, and the outgoing hot water temperature detected by the outgoing hot water temperature detecting means, It is characterized in that to start / stop heating operation of the auxiliary heat source apparatus based on the temperature difference between the temperature and the predicted tapping temperature.

  According to a second aspect of the present invention, there is provided an auxiliary heat source unit according to the first aspect of the invention, wherein the calculation of the predicted hot water temperature and the start / stop control of the heating operation of the auxiliary heat source unit are performed in an auxiliary control unit that controls the auxiliary heat source unit. It is a feature.

  According to the first aspect of the present invention, the predicted hot water temperature is calculated from the bypass ratio when the bypass adjustment valve is fully opened, the detected incoming water temperature, and the detected outgoing hot water temperature, and a preset set temperature and Since the heating operation of the auxiliary heat source machine is configured to start / stop based on the temperature difference from the calculated predicted hot water temperature, the predicted hot water temperature is calculated with a simple arithmetic expression without using a special map, The heating operation of the auxiliary heat source unit can be started / stopped based on the temperature difference between the set temperature and the predicted hot water temperature.

  For this reason, since the arithmetic expression can be commonly used for multiple types of auxiliary heat source machines, the design and production of the control unit for controlling the hot water storage unit and the auxiliary heat source machine or the control unit for controlling the auxiliary heat source machine can be simplified. Since the predicted hot water temperature can be easily calculated based on the above equation even during operation, the calculation load during control can be reduced, and if necessary, the heating unit can be started / stopped in the control section of the auxiliary heat source machine. It becomes possible to decide.

  Moreover, since the predicted hot water temperature is calculated not only using the incoming water temperature and the hot water temperature but also using the bypass ratio when the bypass adjustment valve is fully opened, the predicted hot water temperature that largely reflects the incoming water temperature and reflects the lower hot water temperature. The predicted hot water temperature that represents the incoming water temperature after several seconds in the vicinity of the combustion stop timing can be calculated, and the timing for stopping the heating operation can be appropriately set based on this predicted hot water temperature.

  According to the invention of claim 2, since the calculation of the predicted hot water temperature and the start / stop control of the heating operation of the auxiliary heat source unit are performed in the auxiliary control unit that controls the auxiliary heat source unit, a disconnection of the signal line or the like occurs. In such a case, it is possible to control the start / stop of the heating operation autonomously on the auxiliary heat source machine side.

It is a schematic block diagram of the hot water storage hot-water supply apparatus which concerns on the Example of this invention. It is a flowchart of the combustion start stop control which controls the combustion start / combustion stop of the auxiliary heat source machine of a hot water storage hot-water supply apparatus. Changes in the tank hot water temperature from the hot water storage tank, can body outlet temperature (hot water temperature), incoming water temperature, hot water supply temperature, flow rate, and predicted bypass fully open hot water temperature from the start of combustion of the auxiliary heat source machine to the predetermined period after the combustion stopped. FIG.

  Hereinafter, modes for carrying out the present invention will be described based on examples.

First, the overall structure of the hot water storage and hot water supply apparatus 1 of the present invention will be described.
As shown in FIG. 1, a hot water storage and hot water supply apparatus 1 includes hot water storage, hot water supply, hot water supply to a bathtub, chasing of a bathtub, supply of heating water to a hot water heating terminal such as a floor heating panel, etc. The hot water storage unit 2 having the hot water storage tank 3, the external main heat source unit 4 for heating the hot water in the hot water storage tank 3, and the temperature of the hot water from the hot water storage tank 3 is lower than the set temperature. An auxiliary heat source machine 5 for reheating, a hot water storage unit 2, a main heat source machine 4, a control unit 9 for controlling the auxiliary heat source machine 5 and the like are provided.

  In this hot water storage hot water supply apparatus 1, the hot water storage unit 2 and the auxiliary heat source unit 5 are installed apart (for example, separated by about 1.5 m to 10 m). The hot water storage tank 3 of the hot water storage unit 2 and the auxiliary heat source machine 5 are connected via an external hot water passage portion 7c of the hot water passage 7 having a long piping length. As the external main heat source unit 4, a heat pump type heat source unit or a fuel cell power generator is used, but is not particularly limited thereto, and can be changed as appropriate.

Next, the hot water storage unit 2 will be described.
As shown in FIG. 1, the hot water storage unit 2 includes a hot water storage tank 3, a water supply passage 6, a hot water passage 7, a hot water circulation circuit 8, various valves such as a mixing valve 13, various sensors, various pumps, A control unit 20 and the like are provided, and most of these are housed in the outer case 11.

  The hot water storage tank 3 is composed of a sealed tank capable of storing high-temperature hot water (for example, 65 to 90 ° C.) heated by an external main heat source unit 4, and a heat insulating material is provided around the tank to prevent heat dissipation of the stored hot water. Covered with. A plurality of temperature sensors 17a to 17d are sequentially provided on the outer peripheral portion of the hot water storage tank 3 from the lower side toward the upper side, and the hot water of the plurality of reservoirs in the hot water storage tank 3 is provided by the plurality of temperature sensors 17a to 17d. The temperature is detected.

  The water supply passage 6 supplies low-temperature water from a water supply source to the hot water storage tank 3 and the like, and has an upstream water supply passage portion 6a and a downstream water supply passage portion 6b. The upstream end is connected to the water supply source, and the downstream end is It is connected to the lower part of the hot water storage tank 3. A bypass passage 12 connected to the hot water supply passage 7 is branched from between the upstream water supply passage portion 6a and the downstream water supply passage portion 6b. A temperature sensor 17e is provided in the upstream water supply passage 6a, and a check valve 19a is provided in the downstream water supply passage 6b. A check valve 19 b is provided in the bypass passage 12.

  The hot water supply passage 7 supplies hot water stored in the hot water storage tank 3 to a desired hot water supply destination such as a hot water tap through the auxiliary heat source unit 5, and includes an upper effluent hot water passage portion 7a, a lower effluent hot water passage portion 7b, It has an external hot water supply passage portion 7c and a heat source hot water supply passage portion 7d, the upstream end is connected to the upper part of the hot water storage tank 3, and the downstream end is connected to a hot water tap or the like. A temperature sensor 17f and a flow rate sensor 18a are provided in the upper effluent hot water passage portion 7a, and a temperature sensor 17g and a flow rate sensor 18b are provided in the lower effluent hot water passage portion 7b.

  A mixing valve 13 is provided between the upper effluent hot water passage portion 7 a and the lower effluent hot water passage portion 7 b, and a bypass passage 12 branched from the water supply passage 6 is connected to the mixing valve 13. The mixing valve 13 adjusts the mixing ratio of the low-temperature water from the water source and the high-temperature hot water from the hot water storage tank 3 so that the hot water temperature becomes the target hot water supply set temperature. A branch passage 14 branched from the bypass passage 12 is connected to the lower effluent hot water passage portion 7b, and an open / close valve 15 for avoiding high temperature hot water is provided in the branch passage 14.

  An auxiliary heat source machine 5 is provided between the external hot water supply passage portion 7c and the heat source hot water supply passage portion 7d. In addition, the pipe length of the external hot water outlet passage portion 7c is, for example, about 1.5 m to 10 m and is installed in the outer case 11 because of the structure in which the hot water storage tank unit 2 and the auxiliary heat source unit 5 are installed in a spaced manner. It is set longer than the outflow hot water passage portion 7a and the lower outflow hot water passage portion 7b.

  The hot water circulation circuit 8 is a closed circuit that heats hot water by circulating hot water between the hot water storage tank 3 and the external main heat source unit 4, and has a low temperature side circulation passage portion 8a, a high temperature side circulation passage portion 8b, and the like. The upstream end is connected to the lower part of the hot water storage tank 3, and the downstream end is connected to the upper part of the hot water storage tank 3. An external main heat source unit 4 is provided between the low temperature side circulation passage portion 8a and the high temperature side circulation passage portion 8b. A circulation pump 16 is provided in the low temperature side circulation passage portion 8a.

Next, the auxiliary heat source unit 5 will be described.
As shown in FIG. 1, the auxiliary heat source unit 5 is configured by a known gas water heater (bypass type water heater) provided in the middle of a hot water passage 7 extending from the hot water storage tank 3. The auxiliary heat source unit 5 is set in a combustion prohibited state when there is sufficient hot water in the hot water storage tank 3, but only when the outlet temperature of the mixing valve 13 or the incoming water temperature of the auxiliary heat source unit 5 is lowered. The hot water flowing from the hot water storage unit 2 is heated so that the combustion prohibition state is canceled and the combustion operation is performed to reach the target hot water supply set temperature.

  That is, the auxiliary heat source unit 5 includes a blower fan (not shown) for supplying combustion air, a burner unit 5a for burning fuel gas, a water inlet passage portion 21 through which hot water flows from the hot water storage tank unit 2, and the water inlet passage portion. A heat exchanger 22 for heating hot water flowing in from the combustion gas, a discharge passage section 23 for discharging hot water heated by the heat exchanger 22, a bypass passage 24 for bypassing the heat exchanger 22, and this bypass A bypass flow rate adjusting valve 25 that adjusts the flow rate of hot water flowing through the passage 24, an auxiliary control unit 26 that controls the auxiliary heat source unit 5, various sensors, and the like are provided, most of which are housed in an exterior case 27. ing.

  The heat exchanger 22 is provided on the downstream side in the flowing direction of the hot water and the sensible heat recovery heat exchanger 22a for recovering mainly sensible heat of the combustion gas, and provided on the upstream side in the flowing direction of the hot water and after the sensible heat recovery. A latent heat recovery heat exchanger 22b that mainly recovers the latent heat of the combustion exhaust gas, a drain water recovery unit (not shown) that recovers the drain water generated by the latent heat recovery heat exchanger 22b, and the like are provided.

  The upstream end of the water inlet passage 21 is connected to the downstream end of the external hot water outlet passage 7c extending from the hot water storage tank unit 2, and the downstream end of the water inlet passage 21 is connected to the latent heat recovery heat exchanger 22b. A temperature sensor 28 a and a flow rate sensor 29 are provided in the water inlet passage 21. A bypass passage 24 branched from the upstream side of the temperature sensor 28a and the flow rate sensor 29 of the incoming water passage portion 21 is connected to the hot water passage portion 23, and a bypass flow rate adjusting valve 25 is provided at this branch portion.

  The upstream end of the hot water passage portion 23 is connected to the sensible heat recovery heat exchanger 22a, and the downstream end of the hot water passage portion 23 is connected to the upstream end of the heat source hot water passage portion 7d. A temperature sensor 28 b is provided on the upstream side of the connection portion to which the bypass passage 24 of the hot water passage portion 23 is connected, and a temperature sensor 28 c is provided on the downstream side of the connection portion of the hot water passage portion 23.

  In the bypass flow rate adjustment valve 25, the valve position is adjusted to the bypass passage 24 side fully open so that the flow rate of the bypass passage 24 is maximized during the tank hot water, and the high temperature heated by the heat exchanger 22 is high during the backup hot water. The valve position is adjusted as appropriate so that hot water and low temperature hot water flowing through the bypass passage 24 are mixed and adjusted so that hot water having a hot water supply set temperature is discharged from the auxiliary heat source unit 5.

Next, the control unit 9 will be described.
This hot water storage and hot water supply apparatus 1 is controlled by a control unit 9 including a main control unit 20 and an auxiliary control unit 26. On the hot water storage unit 2 side, detection signals of various sensors are transmitted to the main control unit 20, and on the auxiliary heat source unit 5, detection signals of various sensors are transmitted to the auxiliary control unit 26. By the auxiliary control unit 26, the operation of the hot water storage unit 2, the operation of the main heat source unit 4, the operation of the auxiliary heat source unit 5, the operation / stop of various pumps, the switching of the opening / closing states of various valves, the opening degree adjustment, etc. Control and execute various operations (hot water storage operation, hot water operation, etc.).

  The main control unit 20 can perform data communication with the auxiliary control unit 26 of the auxiliary heat source unit 5, and the main control unit 20 can perform data communication with an operation remote controller (not shown) that can be operated by the user. When various operations are set by the switch operation of the operation remote controller, the command signal is transmitted from the operation remote controller to the main control unit 20. For example, when the target hot water set temperature is set by operating the switch of the operation remote controller, the target hot water set temperature data is transmitted from the operation remote controller to the main control unit 20.

  The main control unit 20 is connected to the auxiliary heat source unit according to the hot water storage status of the hot water storage tank 3 or the hot water discharge temperature from the hot water storage tank 3 (the hot water temperature of the mixing valve 13 or the incoming water temperature of the auxiliary heat source unit 5). 5 is executed, the combustion prohibition flag is reset to “0” when combustion is permitted, and the combustion prohibition flag is set to “1” when combustion is prohibited. The control unit 26 is instructed whether or not the auxiliary heat source machine 5 is combustible.

Next, the combustion start / stop control for controlling the combustion start / combustion stop of the auxiliary heat source unit 5 will be described based on the flowchart of FIG. In this embodiment, this combustion start / stop control is executed by the auxiliary control unit 26 of the auxiliary heat source unit 5.
When this control is started, it is determined in S1 whether or not a predetermined condition that requires combustion of the auxiliary heat source unit 5 for backup hot water is satisfied. If the hot water is being discharged to a hot water tap, a bathtub, or the like (the flow sensor 29 is detecting the flow rate), it is determined that the predetermined condition is satisfied.

  Next, in S2, the detection signals of the temperature sensors 28a and 28b are read, and the incoming water temperature Ti supplied to the auxiliary heat source unit 5 and the hot water temperature To of the auxiliary heat source unit 5 (the outlet temperature of the heat exchanger 22, Can body temperature) is detected. Next, in S3, the bypass fully open predicted hot water temperature Ta when the bypass flow rate adjustment valve 25 is fully opened is calculated by the following equation.

Ta = (Ti × Bypass Fully Open Ratio + To × 1) / (Bypass Fully Open Ratio + 1) (1)
This bypass fully open predicted hot water temperature Ta assumes that the bypass flow rate adjustment valve 25 is fully opened, and the ratio of the flow rate to the bypass passage 24 and the flow rate to the heat exchanger 22 side is fully open (for example, 2: 1). In this case, the hot water supply temperature Tu (temperature at the temperature sensor 28c) on the downstream side of the joining portion between the bypass passage 24 and the hot water passage portion 23 is shown.

  Next, in S4, it is determined whether or not the predicted hot water temperature Ta ≦ (hot water supply set temperature Ts−4 ° C.). If the incoming water temperature Ti and the hot water temperature To are low and the determination in S4 is Yes, in S5 Then, the heating operation (combustion) of the auxiliary heat source unit 5 is started, and the combustion is continued when the combustion is in progress. Thereafter, the process proceeds to S6. Also when the determination of S4 is No, the process proceeds to S6.

  In S6, it is determined whether or not the predicted hot water temperature Ta ≧ (hot water supply set temperature Ts−2 ° C.). If the determination is Yes, the heating operation (combustion) of the auxiliary heat source machine is stopped in S7, and S1 to S1. When the determination in S6 is No, the process also returns to S1, and then S1 and subsequent steps are repeatedly executed.

  Here, in FIG. 3, the hot water temperature Tk of the hot water storage tank 3, the flow rate, the incoming water temperature Ti to the auxiliary heat source machine, the outlet temperature To (can temperature) of the heat exchanger, and the hot water supply temperature Tu at the outlet of the auxiliary heat source machine 5 are shown. (The hot water supply temperature to the hot water supply destination), the valve position of the flow rate adjusting valve 25, the bypass fully open predicted hot water temperature Ta, and the combustion prohibition flag are illustrated.

  When the hot water is started and the flow rate is generated at time t1, the combustion prohibition flag is reset to “0”, and the combustion start / stop control is started. At this time, since the incoming water temperature Ti and the can body temperature To are sufficiently low and the predicted hot water temperature Ta is sufficiently low, the determination of S4 in the flowchart is Yes, and combustion of the auxiliary heat source unit 5 starts at time t2. Is done.

  Thereafter, the can body temperature To and the hot water supply temperature Tu rise rapidly, the hot water temperature Tk from the hot water storage tank 3 also rises, and the predicted hot water temperature Ta gradually rises, as if following this predicted hot water temperature Ta. The incoming water temperature Ti gradually rises behind this. On the other hand, the valve position of the flow rate adjusting valve 25 is switched in the direction of increasing the flow rate to the bypass passage 24. Thereafter, the combustion prohibition flag is set at time t3. At time t4, the determination of S6 in the flowchart becomes Yes, so that combustion of the auxiliary heat source unit 5 is stopped.

  The can body temperature To suddenly decreases slightly after the combustion is stopped, the predicted hot water temperature Ta and the incoming water temperature Ti are gradually increased, the hot water supply temperature Tu is maintained at a temperature close to the hot water supply set temperature Ts, and the combustion is stopped (time t4). After about 10 seconds, the can body temperature To, the predicted hot water temperature Ta, the incoming water temperature Ti, and the hot water supply temperature Tu converge to one point at a temperature substantially equal to the hot water supply set temperature Ts. This indicates that the timing of stopping the combustion was extremely appropriate.

  Here, near the time t4 when the combustion is stopped, the predicted hot water temperature Ta and the incoming water temperature Ti change with the same rising characteristics, and the incoming water temperature Ti is delayed by about 5 seconds with respect to the predicted hot water temperature Ta. It has become. That is, the incoming water temperature Ti after about 5 seconds can be estimated from the predicted hot water temperature Ta, and the auxiliary heat source machine 5 for backup hot water supply 5 is used under the condition of the predicted hot water temperature Ta ≧ (hot water supply set temperature Ts−2 ° C.). By stopping the combustion, the hot water supply temperature Tu can be made substantially coincident with the hot water supply set temperature Ts by heating without excess or deficiency.

Next, the operation and effect of the hot water storage hot water supply apparatus 1 of the present invention will be described.
During normal tank hot water, hot hot water is pushed out from the upper part of the hot water storage tank 3 to the upper effluent hot water passage portion 7 a by the feed water pressure applied to the hot water storage tank 3, and this hot hot water is supplied from the bypass passage 12 at the mixing valve 13. It is mixed with low temperature water and adjusted to the hot water supply set temperature Ts, and most of the hot water at the hot water supply set temperature Ts is discharged from the hot water tap via the bypass passage 24 of the auxiliary heat source unit 5 in the combustion prohibited state. However, some hot water is discharged from the hot water tap via the heat exchanger 22.

  When hot water having a temperature lower than the hot water supply set temperature Ts is discharged from the hot water storage unit 2, the combustion of the auxiliary heat source unit 5 is started by the combustion start / stop control as described above, and the auxiliary heat source unit is started from the external hot water passage passage portion 7c. A part of the hot water supplied to 5 is heated by the heat exchanger 22, and the remaining hot water passed through the bypass passage 24 and the hot water heated by the heat exchanger 22 are mixed in the heat source outlet passage portion 7d to set hot water supply. Hot water is discharged at the temperature Ts.

  In the combustion start / stop control, the bypass fully-open predicted hot water temperature Ta is calculated by the arithmetic expression (1) shown in S3 of the flowchart, and when the predicted hot water temperature Ta is equal to or lower than (hot water supply set temperature Ts-4 ° C), Combustion of the auxiliary heat source unit 5 is started, and combustion of the auxiliary heat source unit 5 is stopped when the predicted hot water temperature Ta is equal to or higher than (hot water supply set temperature Ts−2 ° C.). By using this predicted hot water temperature Ta, the timing of stopping combustion can be set appropriately.

  Since the calculation formula (1) can be calculated using the detected incoming water temperature Ti and the detected hot water temperature To in addition to the bypass full open ratio, the control processing load on the control is small, and the design of the auxiliary control unit 26 is also reduced. It will be easy.

  In addition, since the auxiliary control unit 26 that controls the auxiliary heat source unit 5 is configured to perform the combustion start / stop control, the auxiliary control unit 26 also performs disconnection of the communication line between the main control unit 20 and the auxiliary control unit 26. Since combustion start / stop can be executed, fail-safe can be achieved.

Next, a mode in which the above embodiment is partially changed will be described.
[1] “−4 ° C.” of (hot water set temperature Ts−4 ° C.) in the flowchart is an example, and “−2 ° C.” of (hot water set temperature Ts−2 ° C.) is also an example. It is not limited, and different values may be adopted depending on the model.

[2] In addition, those skilled in the art can implement the present invention by adding various modifications without departing from the spirit of the present invention, and the present invention includes such modifications. It is.

DESCRIPTION OF SYMBOLS 1 Hot water storage hot water supply device 2 Hot water storage unit 3 Hot water storage tank 5 Auxiliary heat source machine 5a Burner unit 7 Hot water passage 9 Control unit (control means)
21 Water entry passage (water entry side passage)
22 Heat exchanger 23 Hot water passage section (hot water side passage)
24 Bypass passage 25 Bypass flow adjustment valve (Bypass adjustment valve)
26 Auxiliary control unit 28a Temperature sensor (incoming water temperature detection means)
28b Temperature sensor (Tapping temperature detection means)

Claims (2)

An auxiliary heat source device that is disposed in a hot water supply passage of the hot water storage unit and reheats hot water supplied from the hot water storage unit to discharge hot water at a preset temperature, and includes a heating unit, a water inlet side passage, a hot water side passage, A bypass passage connecting the inlet side passage and the outlet side passage by bypassing the heating unit, a bypass adjusting valve for adjusting the amount of water flowing in the bypass passage, and an inlet temperature for detecting the temperature of the hot water flowing in the inlet side passage In an auxiliary heat source machine comprising detection means and a hot water temperature detection means for detecting the temperature of hot water flowing in the hot water side passage on the upstream side from the junction of the bypass passage,
The predicted hot water temperature is calculated from the bypass ratio when the bypass adjustment valve is fully opened, the incoming water temperature detected by the incoming water temperature detecting means, and the outgoing hot water temperature detected by the outgoing hot water temperature detecting means, and the setting An auxiliary heat source machine that starts / stops the heating operation of the auxiliary heat source machine based on a temperature difference between a temperature and the predicted hot water temperature.   The auxiliary heat source unit according to claim 1, wherein the calculation of the predicted hot water temperature and the start / stop control of the heating operation of the auxiliary heat source unit are performed in an auxiliary control unit that controls the auxiliary heat source unit.