Hot water system

Abstract

To provide a hot water supply system capable of securely delivering hot water from a hot water delivery terminal.SOLUTION: A hot water supply system has: an instantaneous hot water circulation circuit for circulating hot water between a hot water supply source and a hot water delivery terminal 400; instantaneous hot water temperature detection means 74 for detecting a temperature of hot water in the instantaneous hot water circulation circuit; and an instantaneous hot water circulation pump 73 provided in the instantaneous hot water circulation circuit. After an operation of the instantaneous hot water circulation pump 73 is started, when the temperature of the hot water in the instantaneous hot water circulation circuit becomes a predetermined instantaneous hot water stop temperature or more and an operating time from the start of the operation of the instantaneous hot water circulation pump 73 becomes a predetermined instantaneous hot water stop time or more, the instantaneous hot water circulation pump 73 is stopped.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a hot water supply system, and more particularly to a hot water supply system having an instant hot water function. [Background technology]

[0002] Conventionally, an electric water heater has been proposed that includes a hot water circulation pipe that forms a circulation flow path between a hot water storage tank, a hot water pipe, and a water supply pipe, a circulation pump that circulates hot water within the hot water circulation pipe, and a circulation temperature sensor that detects the temperature of the hot water within the hot water circulation pipe, and that has an instant hot water function that activates and stops the circulation pump based on the temperature detected by the circulation temperature sensor (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-19967 Summary of the Invention [Problem to be solved by the invention]

[0004] In hot water supply systems used in facilities such as hair salons, a hot water supply source including a heating source and a hot water storage tank is installed outside the facility to stably supply a large amount of hot water at a predetermined temperature to multiple hot water terminals, such as showers and faucets. The hot water supply source and the hot water terminals are connected by a piping of a certain length. In such hot water supply systems, when hot water is not used at the hot water terminals, the piping cools down due to natural heat dissipation. Therefore, when hot water is used again at the hot water terminals, the hot water is discharged from the hot water terminals at a low temperature, which deteriorates the temperature control performance. For this reason, as described in Patent Document 1, a circulation circuit is connected between the hot water supply source and the hot water terminals, and a circulation pump and a temperature sensor are installed in the circulation circuit. When the temperature detected by the temperature sensor drops, the circulation pump is activated to raise the temperature of the hot water in the circulation circuit.

[0005] However, when the piping is long, the ambient temperature in some parts of the pipe space where the piping is laid may be high, or a heating means such as a heater may be installed in the piping to prevent freezing. Furthermore, the piping that supplies hot water from the hot water supply source to the hot water outlet terminal and the piping that returns hot water from the hot water outlet terminal to the hot water supply source may be arranged on different piping routes. Therefore, depending on the location of the temperature sensor, the temperature sensor may detect the temperature of the locally heated hot water, causing the circulation pump to stop operating before the temperature of the hot water in the circulation circuit rises.

[0006] The present invention is intended to solve the above-mentioned problems, and an object of the present invention is to provide a hot water supply system that can reliably dispense warm water from a hot water dispensing terminal. [Means for solving the problem]

[0007] According to the present invention, a hot water source that supplies hot water to the hot water outlet terminal; an instant hot water circulation circuit that circulates hot water between the hot water source and the hot water outlet terminal; an instant hot water temperature detection means for detecting the temperature of the hot water in the instant hot water circulation circuit; an instant hot water circulation pump provided in the instant hot water circulation circuit; A control device that executes instant hot water control by operating the instant hot water circulation pump to raise the temperature of the hot water in the instant hot water circulation circuit, A hot water supply system is provided in which the control device has a control configuration that stops the instant hot water circulation pump after starting operation of the instant hot water circulation pump, when the temperature of the hot water in the instant hot water circulation circuit reaches or exceeds a predetermined instant hot water stop temperature and the operating time from the start of operation of the instant hot water circulation pump reaches or exceeds a predetermined instant hot water stop time.

[0008] According to the hot water supply system, after the instant hot water circulation pump starts operating, if the temperature of the hot water in the instant hot water circulation circuit exceeds a predetermined instant hot water stop temperature and the operation time of the instant hot water circulation pump exceeds a predetermined instant hot water stop time, the instant hot water circulation pump is stopped. Therefore, even if only a portion of the piping is heated and the temperature of the hot water locally in the instant hot water circulation circuit exceeds the predetermined instant hot water stop temperature, the instant hot water circulation pump will continue to operate until the predetermined instant hot water stop time. This allows the temperature of the hot water in the instant hot water circulation circuit to be raised, so that warm hot water can be reliably dispensed from the hot water dispense terminal.

[0009] Preferably, in the hot water supply system, The hot water supply source includes a heating heat source, a hot water storage tank for storing hot water heated by the heating heat source, and a heating circulation circuit for circulating the hot water between the heating heat source and the hot water storage tank; The instant hot water circulation circuit is formed between the hot water storage tank and the hot water outlet terminal. The instant hot water stop temperature is set lower than the set hot water storage temperature of the hot water stored in the hot water storage tank.

[0010] According to the hot water supply system, the hot water supply source includes a heating heat source, a hot water storage tank that stores hot water heated by the heating heat source, and a heating circulation circuit that circulates the hot water between the heating heat source and the hot water storage tank. The instant hot water circulation circuit is formed between the hot water storage tank and the hot water outlet terminal. The instant hot water stop temperature is set lower than the hot water storage setting temperature of the hot water stored in the hot water storage tank. Therefore, when hot water at the instant hot water stop temperature in the instant hot water circulation circuit returns to the hot water storage tank, and hot water is supplied from the hot water storage tank to the heating heat source, the hot water delivered from the hot water storage tank can be reliably heated by the heating heat source. This allows hot water heated by the heating heat source to be returned to the hot water storage tank, so that hot water at a predetermined hot water supply temperature can be supplied from the hot water storage tank to the hot water outlet terminal.

[0011] Preferably, in the hot water supply system, The instant hot water stop time is set according to the length of the hot water supply pipe from the hot water storage tank to the hot water outlet terminal.

[0012] According to the hot water supply system, the instant hot water stop time is set according to the length of the hot water supply pipe from the hot water storage tank to the hot water outlet terminal, so the temperature of the hot water in the hot water supply pipe can be increased and the amount of hot water returned from the instant hot water circulation circuit to the hot water storage tank can be limited, preventing unnecessary hot water circulation and suppressing the collapse of the temperature stratification of hot water in the hot water storage tank caused by excessive hot water circulation. This allows hot water at a predetermined hot water supply temperature to be supplied from the hot water storage tank to the hot water outlet terminal. [Effects of the Invention]

[0013] As described above, according to the present invention, it is possible to provide a hot water supply system that can reliably dispense warm water from a hot water dispensing terminal. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram showing an example of a hot water supply system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a flowchart showing a control operation in the instant hot water supply control of the hot water supply system according to the embodiment of the present invention. [Figure 3] FIG. 3 is a data table showing the correspondence relationship between the pipe length and the instant hot water stop time in the instant hot water control of the hot water supply system according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, a hot water supply system according to an embodiment of the present invention will be described. FIG. 1 is a schematic diagram showing an example of a hot water supply system according to this embodiment. This hot water supply system can be used in commercial facilities such as hair salons. The hot water supply system includes a hot water pressurized tank unit 1 and a heat source unit 500. The hot water pressurized tank unit 1 supplies cold water and hot water to multiple hot water outlet terminals 400, such as showers and faucets. The heat source unit 500 includes a first gas heat source unit 501 and a second gas heat source unit 502, which are heating heat sources. The hot water pressurized tank unit 1 includes a water supply tank 2 that receives primary water supply and a hot water storage tank 6 that stores hot water heated by the first and second gas heat source units 501 and 502. The hot water supply system may include one or three or more gas heat source units as a heating heat source, and may use a heat pump, electric heater, or the like instead of the gas heat source units.

[0016] The first and second gas heat source units 501, 502 are gas water heaters, and although not shown, each has a heating unit with a gas burner, heat exchanger, etc. inside the housing. The first and second gas heat source units 501, 502 and the hot water storage tank 6 are connected by a heating circulation circuit consisting of a heating supply pipe 40 that sends hot water from the hot water storage tank 6 and water from the water supply tank 2 to the first and second gas heat source units 501, 502, and a heating return pipe 44 that returns the hot water heated in the first and second gas heat source units 501, 502 to the hot water storage tank 6. In this embodiment, the first and second gas heat source units 501, 502, the hot water storage tank 6, the heating supply pipe 40, and the heating return pipe 44 constitute a hot water supply source.

[0017] One end of the heating supply pipe 40 is connected to the bottom of the hot water storage tank 6, and the other end is branched into a first heating supply pipe 41 and a second heating supply pipe 42 so as to be connected to a first gas heat source unit 501 and a second gas heat source unit 502. The heating return pipe 44 is formed by joining a first heating return pipe 45 and a second heating return pipe 46, each of which has one end connected to the gas heat source units 501, 502, and the other end is connected to the top of the hot water storage tank 6. A heating supply temperature sensor 50 is disposed in the heating supply pipe 40 upstream of the branch point of the first and second heating supply pipes 41, 42 and downstream of the junction with the water supply pipe 3, which will be described later.

[0018] A first heating circulation pump 51 and a second heating circulation pump 52 are provided in the first and second heating supply pipes 41 and 42, respectively, and check valves 53 and 54 are provided downstream of the first and second heating circulation pumps 51 and 52. Therefore, by operating the first and second heating circulation pumps 51 and 52 and the first and second gas heat source units 501 and 502, hot water heated by the first and second gas heat source units 501 and 502 is stored in the hot water storage tank 6. The first and second heating circulation pumps 51 and 52 are connected to a hot water supply control device C, and their operation, stop, and rotation speed are controlled by control signals from the hot water supply control device C. In addition, the heat source unit controllers C1 and C2 of the first and second gas heat source units 501 and 502 are connected to the hot water supply control device C, and the operation of the first and second gas heat source units 501 and 502 is controlled by control signals from the hot water supply control device C. The detection signal of the detected temperature detected by the heating supply temperature sensor 50 is output to the hot water control device C, and detection signals such as the detected temperature detected by various sensors not shown arranged in the gas heat source machines 501 and 502 are output to the heat source machine control devices C1 and C2.

[0019] An under-tank temperature sensor 55 for detecting the temperature of the hot water supplied from the hot water storage tank 6 to the heating supply pipe 40, and a valve 56 are installed upstream of the junction with the water supply pipe 3 in the heating supply pipe 40 connected to the lower part of the hot water storage tank 6. A detection signal of the detected temperature detected by the under-tank temperature sensor 55 is output to the hot water supply control device C. The valve 56 can be opened and closed manually, but it may also be configured so that its opening and closing is controlled by a control signal from the hot water supply control device C.

[0020] The hot water storage tank 6 is made of a corrosion-resistant metal (e.g., stainless steel), and its periphery is covered with a heat insulating material (not shown). The capacity of the hot water storage tank 6 in this embodiment is, for example, 50 L. The lower part of the hot water storage tank 6 is connected to the previously described heating supply pipe 40 and a hot water supply return pipe 72 that returns hot water from the hot water outlet terminal 400 (described later). The upper part of the hot water storage tank 6 is connected to the previously described heating return pipe 44 and a hot water supply supply pipe 71 that connects to the hot water outlet terminal 400 (described later). The hot water storage tank 6 is equipped with a first hot water temperature sensor 61, a second hot water temperature sensor 62, and a third hot water temperature sensor 63, which detect the temperature of the hot water inside, attached in this order from top to bottom at a predetermined interval. The hot water supply pressurization tank unit 1 also includes an outside air temperature sensor 80 below the hot water storage tank 6 for detecting the outside air temperature. The temperature signals detected by these temperature sensors 61, 62, 63, and 80 are output to the hot water supply control device C.

[0021] An automatic air vent valve 57 for venting air from the hot water storage tank 6 and a heated return temperature sensor 58 for detecting the temperature of the hot water flowing into the hot water storage tank 6 are installed in the heated return pipe 44 connected to the top of the hot water storage tank 6. A detection signal of the detected temperature detected by the heated return temperature sensor 58 is output to the hot water supply control device C.

[0022] A substantially rectangular box-shaped water supply tank 2 is disposed above the hot water storage tank 6 to supply water to the gas heat source units 501 and 502, the hot water storage tank 6, and the hot water outlet terminal 400. In this embodiment, the capacity of the water supply tank 2 is, for example, 45 L. A primary water supply pipe 10, through which city water flows, is connected to the top of the water supply tank 2, and a water supply pipe 3 is connected to the bottom of the water supply tank 2. The primary water supply pipe 10 branches into two pipes, a first primary water supply pipe 11 and a second primary water supply pipe 12, which are connected to the water supply tank 2. The first and second primary water supply pipes 11 and 12 are respectively provided with, in order from upstream, a first governor 13, a second governor 14, a first water supply solenoid valve 15, and a second water supply solenoid valve 16. The first and second water supply solenoid valves 15 and 16 are connected to the hot water supply control device C and are controlled to open and close by control signals from the hot water supply control device C. In this way, by connecting multiple primary water supply pipes 11, 12 to the water supply tank 2, pressure loss can be reduced and water can be supplied to the water supply tank 2 in a short time. Although not shown, a portion of the water supply tank 2 is open to the atmosphere.

[0023] The water supply tank 2 has an opening in one side wall below the connection ports for the first and second primary water supply pipes 11, 12 and above the connection port for the water supply pipe 3. An overflow pipe 200 is connected to the opening in this side wall. On the other side wall of the water supply tank 2, an overfloat sensor 22, a Hi float sensor 23, a Low float sensor 24, and a low water level float sensor 25 are arranged in this order from top to bottom at predetermined intervals to detect the water level in the water supply tank 2. Although not shown, a substantially U-shaped trap pipe (not shown) is arranged in the water supply tank 2. One end of the trap pipe 2 is connected to the overflow pipe 200, and the other end is at approximately the same height as the overfloat sensor 22 and opens upward. Therefore, excess water is discharged to the outside through the trap pipe and the overflow pipe 200. Water level detection signals detected by the float sensors 22, 23, 24, and 25 are output to the hot water supply control device C.

[0024] One end of the water supply pipe 3 is connected to the bottom of the water supply tank 2, and branches upstream into a first water supply pipe 31 and a second water supply pipe 32 so that water flows in parallel. A water supply booster pump 37 is installed upstream of the branch point between the first water supply pipe 31 and the second water supply pipe 32. The water supply booster pump 37 is connected to the hot water supply control device C, and its operation, stoppage, and rotation speed are controlled by control signals from the hot water supply control device C.

[0025] The first water supply pipe 31 is provided with, from upstream to downstream, a check valve 33 and a pressure sensor (pressure detection means) 35 for detecting water pressure. The second water supply pipe 32 is provided with, from upstream to downstream, a check valve 34 and a water volume sensor (water volume detection means) 36 for detecting water flow rate. While it is possible to incorporate a pressure sensor and a water volume sensor in a single water passage without providing parallel water passages, pressure loss can be reduced by forming water passages so that water flows in parallel and incorporating a pressure sensor and a water volume sensor in each passage. Although the water flow rate differs in each passage, if the pressure loss is known, the water flow rate of the entire water supply pipe 3 can be calculated from the water flow rate detected by the water volume sensor 36. The detection signals of the detected pressure detected by the pressure sensor 35 and the detected flow rate detected by the water volume sensor 36 are output to the hot water supply control device C.

[0026] The first water supply pipe 31 and the second water supply pipe 32 join at a junction downstream of the pressure sensor 35 and the water volume sensor 36, and the other end of the water supply pipe 3 is connected to a junction with a heating supply pipe 40 connected to the bottom of the hot water storage tank 6. The water supply pipe 3 also branches into a water supply pipe 38 connected to the hot water outlet terminal 400 downstream of the junction of the first and second water supply pipes 31 and 32. Therefore, in this embodiment, by operating the water supply pressure pump 37, water is supplied to the hot water storage tank 6, the gas heat source units 501 and 502, and the hot water outlet terminal 400, and the water supply pipe 3, including the first and second water supply pipes 31 and 32 and the water supply pipe 38, constitutes a water supply circuit. The water supply pipe 38 branches into multiple parts depending on the number of showers and faucets in the hot water outlet terminal 400. A check valve 39 is provided in the water supply pipe 3 downstream of the branch point of the water supply outflow pipe 38.

[0027] One end of the hot water return pipe 72 is connected to the bottom of the hot water storage tank 6, and the other end is connected to the hot water supply pipe 71 at the hot water outlet terminal 400. An instant hot water circulation pump 73 is installed in the hot water return pipe 72, and an instant hot water return temperature sensor (instant hot water temperature detection means) 74 and a check valve 75 are installed downstream of the instant hot water circulation pump 73. Therefore, in this embodiment, by operating the instant hot water circulation pump 73, hot water is circulated between the hot water storage tank 6 and the hot water outlet terminal 400, and the hot water supply pipe 71 and the hot water return pipe 72 connecting the hot water storage tank 6 and the hot water outlet terminal 400 constitute an instant hot water circulation circuit.

[0028] The instant hot water control in the hot water supply system of this embodiment will be described later, but to summarize the main operational control, when the hot water tap of the hot water outlet terminal 400 is opened and the water supply pressure pump 37 starts operating, if the temperature of the hot water detected by the third hot water storage temperature sensor 63 is higher than the predetermined hot water storage start temperature, water is supplied from the water supply tank 2 to the hot water storage tank 6 via the water supply pipe 3 and the heating supply pipe 40 below the tank connected to the hot water storage tank 6 without operating the first and second heating circulation pumps 51, 52, and the hot water in the hot water storage tank 6 is supplied to the hot water outlet terminal 400 via the hot water supply supply pipe 71. Furthermore, as the temperature of the hot water decreases due to the supply of water into the hot water storage tank 6, when the temperature of the hot water detected by the third hot water storage temperature sensor 63 falls below the hot water storage start temperature, the first and second heating circulation pumps 51, 52 begin operating, hot water is supplied from the bottom of the hot water storage tank 6 to the heating supply pipe 40, the water from the water supply tank 2 and the hot water from the hot water storage tank 6 are mixed and supplied to the first and second gas heat source units 501, 502. The hot water heated to a predetermined hot water outlet temperature in the first and second gas heat source units 501, 502 is then returned to the hot water storage tank 6 via the heating return pipe 44. Furthermore, hot water is sent from the hot water storage tank 6 to the hot water supply supply pipe 71, and hot water is supplied to the hot water outlet terminal 400 via the hot water supply supply pipe 71 (hot water outlet control).

[0029] Furthermore, when all hot water outlet terminals 400 are closed and the temperature of the hot water detected by the third hot water storage temperature sensor 63 falls below the hot water storage start temperature, the first and second heating circulation pumps 51, 52 begin to operate, the hot water in the hot water storage tank 6 is supplied to the first and second gas heat source units 501, 502, and the hot water heated to a predetermined hot water outlet temperature in the first and second gas heat source units 501, 502 is returned to the hot water storage tank 6, thereby maintaining the temperature of the hot water in the hot water storage tank 6 (hot water storage control).

[0030] The first and second heating circulation pumps 51, 52 are operated simultaneously or individually depending on the amount of hot water used at the hot water outlet terminal 400, and the first and second gas heat source units 501, 502 are also operated simultaneously or individually accordingly.

[0031] The hot water supply system includes a hot water supply control device C provided in the hot water supply pressurized tank unit 1, heat source machine control devices C1 and C2 provided in the first and second gas heat source machines 501 and 502, and a remote control R for a user to perform operations related to the operation of the hot water supply system. The hot water supply control device C and the heat source machine control devices C1 and C2 are connected to each other by wire or wirelessly so that they can communicate with each other, and the hot water supply control device C and the remote control R are connected to each other by wire or wirelessly so that they can communicate with each other.

[0032] The remote control R is a terminal device configured to instruct the hot water supply control device C on operational information such as turning the power of the hot water supply system on and off, the hot water storage temperature setting for the hot water in the hot water storage tank 6 (the hot water outlet temperature of the hot water dispensed from the first and second gas heat source units 501, 502 in hot water outlet control and hot water storage control), and setting the water pressure mode in response to the user's operation of an operation switch (not shown). The remote control R is equipped with a display that displays various information about the hot water supply system. Note that a mobile terminal such as a smartphone or tablet terminal connected to the hot water supply control device C so as to be able to communicate with it can be used instead of or together with the remote control R.

[0033] The hot water supply control device C and the heat source machine control devices C1 and C2 each consist of one or more electronic circuit units including a CPU, ROM, RAM, interface circuitry, etc. The memory stores various operation programs and various data such as setting values ​​for executing the operation programs.

[0034] The hot water supply control device C receives detection signals from the various sensors (temperature sensors 50, 55, 58, 61, 62, 63, 74, 80, pressure sensor 35, water volume sensor 36, float sensors 22-25) described above, and also receives operation information from the remote controller R. The heat source machine control devices C1, C2 also receive detection signals from various sensors (not shown) provided in the first and second gas heat source machines 501, 502, and output control signals to the hot water supply control device C. The hot water supply control device C controls the operation of the gas heat source machines 501, 502, the various pumps 37, 51, 52, 73, the water supply solenoid valves 15, 16, and the like, thereby controlling the operation of the entire hot water supply system. Therefore, in this embodiment, the hot water supply control device C and the heat source machine control devices C1, C2 constitute the control devices of the hot water system. It is noted that the operation of the entire hot water supply system may be controlled by a single control device, without providing the heat source machine control devices C1, C2.

[0035] Next, the control operation of the instant hot water supply control in the hot water supply system of this embodiment will be described with reference to FIG. If the remote control R is on and the instant hot water circulation pump 73 is stopped (Yes in step S1), the outside air temperature detected by the outside air temperature sensor 80 is acquired, and a predetermined instant hot water start time t1 is set according to the acquired outside air temperature, and a timer is started (step S2).

[0036] The instant hot water start time t1 is a value determined by experiment, and in the hot water supply system of this embodiment, for example, when the outside temperature is 5°C, the instant hot water start time t1 is 15 minutes. Note that the instant hot water start time t1 can be set appropriately depending on the configuration of the hot water supply system.

[0037] Next, it is determined whether the water flow rate detected by the water volume sensor 36 is equal to or less than a predetermined lower limit flow rate M (e.g., 0.1 L / min) (step S3). If the water flow rate is greater than the lower limit flow rate M (No in step S3), the water dispensing terminal 400 is in use, so the timer is reset.

[0038] If the water flow rate detected by the water volume sensor 36 is below a predetermined lower limit flow rate M (Yes in step S3) and the stop time of the instant hot water circulation pump 73 has continued for more than the instant hot water start time t1 (Yes in step S4), the instant hot water circulation pump 73 is started to operate at a predetermined rotation speed (step S5).

[0039] When the instant hot water circulation pump 73 starts operating, a timer is started to measure the predetermined instant hot water stop time t2, which is set according to the length of the hot water supply pipe 71 from the hot water storage tank 6 to the farthest hot water outlet terminal 400 shown in Figure 3. The instant hot water stop time t2 is also a value determined by experiment and can be set appropriately depending on the configuration of the hot water supply system. Although not shown, the instant hot water circulation circuit is equipped with an orifice. Therefore, when the instant hot water circulation pump 73 is operated at a predetermined rotation speed, the flow rate of hot water flowing through the instant hot water circulation circuit is approximately constant regardless of the piping length. This makes it easy to set the instant hot water stop time t2.

[0040] Next, it is determined whether the operation time of the instant hot water circulation pump 73 continues for longer than the instant hot water stop time t2, and whether the temperature of the hot water detected by the instant hot water return temperature sensor 74 continues to be higher than a predetermined instant hot water stop temperature T2 (e.g., 50°C, preferably lower than the hot water storage start temperature) which is lower than the hot water storage setting temperature (e.g., 60°C) of the hot water storage tank 6 for a predetermined duration tm (e.g., 5 seconds) (steps S6 to S7).

[0041] Then, if the operating time of the instant hot water circulation pump 73 is longer than the instant hot water stop time t2 and the temperature of the hot water remains above the instant hot water stop temperature T2 for a continuous time tm (Yes in steps S6 and S7), the instant hot water circulation pump 73 is stopped (step S9).

[0042] On the other hand, if the operation time of the instant hot water circulation pump 73 is less than the instant hot water stop time t2 (No in step S6), or if the temperature of the hot water has not remained above the instant hot water stop temperature T2 for the duration tm (No in step S7), and the water flow rate detected by the water volume sensor 36 is below the lower limit flow rate M (No in step S8), the instant hot water circulation pump 73 continues to operate until both conditions are met. During instant hot water control, if use of the hot water dispensing terminal 400 begins and the water flow rate becomes greater than the lower limit flow rate M (Yes in step S8), the instant hot water circulation pump 73 is stopped (step S9).

[0043] As described above, according to this embodiment, after the operation of the instant hot water circulation pump 73 is started, if the temperature of the hot water in the instant hot water circulation circuit exceeds the predetermined instant hot water stop temperature and the operation time from the start of operation of the instant hot water circulation pump 73 exceeds the predetermined instant hot water stop time, the instant hot water circulation pump 73 is stopped. Therefore, even if only a portion of the piping is heated and the temperature of the hot water locally in the instant hot water circulation circuit exceeds the predetermined instant hot water stop temperature, the instant hot water circulation pump 73 will operate until the predetermined instant hot water stop time. This allows the instant hot water control to reliably increase the temperature of the hot water in the instant hot water circulation circuit, and ensures that warm hot water can be reliably dispensed from the hot water dispensing terminal 400 even when hot water use is started at any time at the hot water dispensing terminal 400.

[0044] In addition, according to this embodiment, the hot water supply source includes first and second gas heat source units 501, 502, a hot water storage tank 6 that stores hot water heated by the first and second gas heat source units 501, 502, and a heating circulation circuit that circulates hot water between the first and second gas heat source units 501, 502 and the hot water storage tank 6. The instant hot water circulation circuit is formed between the hot water storage tank 6 and the hot water outlet terminal 400, and the instant hot water stop temperature is set lower than the hot water storage setting temperature of the hot water stored in the hot water storage tank 6. Therefore, the circulation of the hot water causes hot water at the instant hot water stop temperature in the instant hot water circulation circuit to return to the hot water storage tank 6. For example, when hot water is supplied to the first and second gas heat source units 501, 502 from the bottom of the hot water storage tank 6 to heat the hot water in the hot water storage tank 6 in the above-mentioned hot water storage control, the hot water can be reliably heated by the first and second gas heat source units 501, 502. This allows the temperature of the hot water in the hot water storage tank 6 to be maintained at or above the hot water storage set temperature, and allows hot water to be supplied to the hot water dispensing terminal 400 at a predetermined hot water supply temperature.

[0045] Furthermore, according to this embodiment, the instant hot water stop time is set according to the piping length of the hot water supply pipe 71 from the hot water storage tank 6 to the hot water outlet terminal 400, so the temperature of the hot water in the hot water supply pipe 71 can be increased and the amount of hot water returned from the instant hot water circulation circuit to the hot water storage tank 6 is limited, preventing unnecessary circulation of hot water and suppressing the collapse of the temperature stratification of hot water in the hot water storage tank 6 that occurs when hot water is circulated excessively. This allows hot water at a predetermined hot water temperature to be stably supplied from the hot water storage tank 6 to the hot water outlet terminal 400.

[0046] As described above, according to this embodiment, a hot water supply system can be provided that can reliably dispense warm water from the hot water dispensing terminal 400, and therefore can be suitably used in facilities such as hair salons and beauty salons. [Explanation of symbols]

[0047] 2 water tanks 3 Water supply pipe 35 Pressure Sensor 36 Water volume sensor 37 Water supply pressure pump 6. Hot water tank 40 Heating supply pipe 44 Heat return pipe 71 Hot water supply pipe 72 Hot water return pipe 73 Instant hot water circulation pump 74 Instant hot water return temperature sensor 501,502 Gas heat source machine C. Hot water control device C1, C2 Heat source machine control device

Claims

[Claim 1] A hot water supply source that includes a heating heat source, a hot water storage tank that stores hot water heated by the heating heat source, and a heating circulation circuit that circulates the hot water between the heating heat source and the hot water storage tank, and supplies hot water to a hot water outlet terminal; a heating circulation pump provided in the heating circulation circuit; An instant hot water circulation circuit that circulates hot water between the hot water storage tank and the hot water outlet terminal; an instant hot water temperature detection means for detecting the temperature of the hot water in the instant hot water circulation circuit; an instant hot water circulation pump provided in the instant hot water circulation circuit; A control device that executes instant hot water control by operating the instant hot water circulation pump to raise the temperature of the hot water in the instant hot water circulation circuit, A hot water supply system having a control configuration in which, after starting the operation of the instant hot water circulation pump, the control device stops the instant hot water circulation pump when the temperature of the hot water in the instant hot water circulation circuit becomes equal to or higher than a predetermined instant hot water stop temperature set below the hot water storage start temperature that starts the operation of the heating circulation pump, which is lower than the hot water storage setting temperature of the hot water storage tank, and when the operating time from the start of operation of the instant hot water circulation pump becomes equal to or higher than a predetermined instant hot water stop time set according to the piping length of the hot water supply pipe from the hot water storage tank to the hot water outlet terminal.

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