Hot water system

Abstract

To supply a stable amount of hot water from a hot water supply terminal.SOLUTION: When a water pressure in a water supply circuit 3 becomes less than a predetermined operation start pressure while a water supply pressurization pump 37 is stopped, a hot water supply system starts operation of the water supply pressurization pump 37 at a predetermined drive start rotation speed lower than a predetermined rated rotation speed, and when the use of a hot water supply terminal 400 is detected while the water supply pressurization pump 37 is started to operate at the drive start rotation speed, it increases a rotation speed of the water supply pressurization pump 37 from the drive start rotation speed to the rated rotation speed.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 in which a water supply pressure control is performed to maintain water pressure in a water supply circuit by operating a water supply pressure pump when a hot water outlet terminal is not in use. [Background technology]

[0002] To reduce the load on the pump, it has been proposed to operate the pump at a starting speed of 60 to 96% of the rated speed for a predetermined time after startup, and then increase the speed from the starting speed to the rated speed after the predetermined time has passed, or to operate the pump at a low speed at the start of startup, and then gradually increase the speed to the rated speed (for example, Patent Document 1 and Patent Document 2).

[0003] However, since it is difficult for an instantaneous water heater alone to supply a large amount of hot water to a hot water outlet terminal, facilities such as hair salons that need to supply a large amount of hot water at a specified hot water temperature to multiple hot water outlet terminals such as showers and faucets have traditionally used a hot water supply system that includes a hot water storage tank that stores hot water heated by a heating heat source, a water supply tank that receives water from a water supply source, a water supply circuit that supplies water from the water supply tank to the heating heat source, the hot water storage tank, and the hot water outlet terminal, and a water supply booster pump installed in the water supply circuit, and the hot water is supplied to the hot water outlet terminal by operating the water supply booster pump.

[0004] In the hot water supply system described above, when the hot water supply terminal is opened and hot water begins to be used, it is necessary to maintain the water pressure in the water supply circuit at a pressurized state so that hot water is steadily dispensed at a predetermined rate from the start of hot water dispensing. Therefore, if the water pressure in the water supply circuit drops when the hot water supply terminal is not in use, a water supply pressurization control is executed to operate the water supply pressure pump to maintain the water pressure in the water supply circuit. Since operating the pump with such a hot water supply terminal closed places a heavy load on the pump, it is preferable for the water supply pressurization control to operate the water supply pressure pump at a starting speed lower than the rated speed, as in Patent Document 1 and Patent Document 2, and then operate it at the rated speed after a predetermined time. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-204531 [Patent Document 2] Japanese Patent Application Publication No. 7-180691 Summary of the Invention [Problem to be solved by the invention]

[0006] However, if the rotation speed of the water supply pressure pump is increased from a low starting rotation speed to a high rated rotation speed after a predetermined time regardless of the hot water usage status at the hot water dispensing terminal, when the user starts using hot water at the hot water dispensing terminal after the water supply pressure control has started, the amount of hot water dispensed will suddenly increase even though the user has not operated the hot water tap. Also, even if the rotation speed of the water supply pressure pump is gradually increased, the amount of hot water dispensed will gradually increase even though the user has not operated the hot water tap. Therefore, in either case, there is a problem that the convenience and comfort of using hot water at the hot water dispensing terminal is impaired.

[0007] The present invention solves the above-mentioned problems, and its object is to dispense hot water at a stable rate from a hot water terminal in a hot water supply system in which water supply pressure control is performed, which operates a water supply pressure pump to maintain water pressure in the water supply circuit when the hot water terminal is not in use. [Means for solving the problem]

[0008] According to the present invention, A heating source; a hot water storage tank for storing hot water heated by a heating heat source; a heating circulation circuit that circulates hot water between the heating heat source and the hot water storage tank; A hot water supply pipe that supplies hot water from the hot water storage tank to the hot water outlet terminal; a water supply tank that receives water supplied from a water supply source; A water supply circuit that supplies water from the water supply tank to the heating heat source, hot water storage tank, and hot water outlet terminal; a water supply pressure pump provided in the water supply circuit; a pressure detection means for detecting the water pressure in the water supply circuit; A usage detection means for detecting the usage of water or hot and cold water at the hot water dispensing terminal; A control device that performs water supply pressure control to maintain the water pressure in the water supply circuit. When the water pressure in the water supply circuit falls below a predetermined operation start pressure while the water supply pressure pump is stopped, the control device starts operation of the water supply pressure pump at a predetermined drive start rotation speed that is lower than a predetermined rated rotation speed, A hot water supply system is provided having a control configuration that increases the rotational speed of the water supply pressure pump from the drive start rotational speed to the rated rotational speed if use of the hot water outlet terminal is detected when the water supply pressure pump starts operating at the drive start rotational speed.

[0009] According to the hot water supply system, when the water pressure in the water supply circuit falls below a predetermined start pressure while the water supply pressure pump is stopped, the water supply pressure pump starts operating at a predetermined start rotation speed that is lower than the predetermined rated rotation speed, thereby reducing the load on the water supply pressure pump. Note that in this specification, the rated rotation speed means the set rotation speed at which the water supply pressure pump operates when the hot water outlet terminal is in use.

[0010] Furthermore, according to the above-mentioned hot water supply system, if use of the hot water outlet terminal is detected when the water supply pressure pump is started at the drive start rotation speed, the rotation speed of the water supply pressure pump is increased from the drive start rotation speed to the rated rotation speed, so that when the hot water outlet terminal is opened at the start of the water supply pressure control, hot water can be immediately dispensed at the specified amount.

[0011] Preferably, in the hot water supply system, If the control device starts the operation of the water supply pressure pump at the drive start rotation speed and does not detect the use of the hot water outlet terminal, it gradually increases the rotation speed of the water supply pressure pump from the drive start rotation speed to the rated rotation speed within a predetermined rotation speed gradual increase time.

[0012] According to the above-mentioned hot water supply system, when the water supply pressure pump is started to operate at the drive start rotation speed, if use of the hot water outlet terminal is not detected, the rotation speed of the water supply pressure pump is gradually increased from the drive start rotation speed to the rated rotation speed within a specified rotation speed gradual increase time, thereby further reducing the load when operating the water supply pressure pump with the hot water outlet terminal closed.

[0013] Preferably, in the hot water supply system, If use of the hot water outlet terminal is detected within the rotation speed gradual increase time, the control device increases the rotation speed of the water supply pressure pump to the rated rotation speed.

[0014] According to the above-mentioned hot water supply system, if use of the hot water outlet terminal is detected within the time for gradually increasing the rotation speed, the rotation speed of the water supply pressure pump is increased to the rated rotation speed. Therefore, if the hot water outlet terminal is opened while the rotation speed of the water supply pressure pump is gradually increasing from the rotation speed at which the pump starts operating, hot water can be immediately dispensed at the specified amount.

[0015] Preferably, in the hot water supply system, When the control device is operating the water supply pressure pump, if the use of the hot water outlet terminal is not detected and the water pressure in the water supply circuit continues to be equal to or higher than a predetermined stop pressure for a predetermined stop determination time, the control device stops the water supply pressure pump.

[0016] In facilities such as hair salons, showers are not only used at low to high flow rates, but are also sometimes used intermittently within short periods of time. For this reason, if the use of the hot water outlet terminal is not detected and the water supply booster pump is stopped immediately when the water pressure in the water supply circuit exceeds a predetermined stop pressure, the water supply booster pump will be operated and stopped frequently, which may reduce its durability.

[0017] However, with the above-mentioned hot water supply system, even if use of the hot water outlet terminal is not detected and the water pressure reaches or exceeds the stop pressure, the water supply booster pump will not be stopped unless this condition continues for a specified stop determination time.This makes it possible to respond to frequent changes in the amount of hot water dispensed at the hot water outlet terminal and prevents a decrease in the durability of the water supply booster pump.

[0018] Preferably, in the hot water supply system, The usage detection means includes a water volume detection means for detecting the flow rate of water flowing through the water supply circuit, When the water volume detection means detects a flow rate greater than a predetermined lower limit flow rate, it detects that the hot water outlet terminal is in use.

[0019] According to the above-mentioned water supply system, the usage detection means includes a water volume detection means that detects the flow rate of water flowing through the water supply circuit, and if the water volume detection means detects a flow rate greater than a predetermined lower limit flow rate, it detects the use of the water outlet terminal, thereby ensuring reliable detection of the use of the water outlet terminal.

[0020] Preferably, in the hot water supply system, A hot water return pipe is provided to return the hot water discharged from the hot water storage tank to the hot water storage tank. The hot water supply system has an instant hot water circulation circuit that circulates hot water between the hot water storage tank and the hot water outlet terminal using a hot water supply supply pipe and a hot water return pipe.

[0021] According to the hot water supply system described above, hot water at a stable hot water temperature can be supplied to the hot water dispensing terminal, and therefore it can be suitably used as a hot water supply system in facilities such as hair salons. [Effects of the Invention]

[0022] As described above, according to the present invention, in a hot water supply system in which water supply pressure control is performed to maintain the water pressure in the water supply circuit by operating the water supply pressure pump when the hot water dispensing terminal is not in use, hot water can be dispensed from the hot water dispensing terminal at a stable rate, thereby improving user convenience and comfort. [Brief explanation of the drawings]

[0023] [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 water supply pressurization control of the hot water supply system according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] 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.

[0025] The first and second gas heat source units 501, 502 are gas water heaters, and although not shown, have a heating unit in the housing that has a gas burner, a heat exchanger, etc. 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.

[0026] 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.

[0027] 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 the detection signal of the detected temperature detected by various sensors not shown in the figure arranged in the gas heat source machines 501 and 502 is output to the heat source machine control devices C1 and C2.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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 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.

[0037] The water supply pressurization 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 pressurization 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).

[0038] 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).

[0039] In addition, when all hot water outlet terminals 400 are closed and a predetermined instant hot water start time has elapsed and the temperature of the hot water stagnating in the hot water supply pipe 71 and the hot water return pipe 72 has dropped, the instant hot water circulation pump 73 begins to operate, and hot water is circulated between the hot water storage tank 6 and the hot water outlet terminals 400 via the hot water supply pipe 71 and the hot water return pipe 72 (instant hot water control).

[0040] 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 setting of the instant hot water control, and accordingly the first and second gas heat source units 501, 502 are also operated simultaneously or individually.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] Next, the control operation of the water supply pressurization control in the hot water supply system of this embodiment will be described with reference to Figure 2. Even when the hot water outlet terminal 400 is not in use, if there is a slight gap in the check valves 33, 34, etc., the water pressure in the water supply circuit will gradually decrease. Therefore, to maintain the water pressure in the water supply circuit, the water supply pressurization control is executed. Note that the hot water supply system of this embodiment is configured to allow selection of multiple water pressure modes, including water-saving mode, low water pressure mode, standard mode, and high water pressure mode, depending on installation conditions such as the elevation difference between the hot water supply pressurization tank unit 1 and the hot water outlet terminal 400 and the piping length, as well as the user's usage pattern. In the water supply pressurization control, a judgment reference value corresponding to each water pressure mode and a control instruction value including the rated rotation speed of the water supply pressurization pump 37 are set. However, the following description will be given using the high water pressure mode as an example.

[0046] When the remote control R is on, no water or hot water is being used at all hot water outlet terminals 400, and the water supply pressure pump 37 is stopped (step S1), the control device C continuously monitors whether the water pressure detected by the pressure sensor 35 is below a predetermined activation pressure f (e.g., 135 kPa) (step S2).

[0047] Then, when the water pressure detected by the pressure sensor 35 falls below the operation start pressure f while the water supply pressure pump 37 is stopped (Yes in step S2), the water supply pressure pump 37 is started to operate (step S3) at a predetermined drive start rotation speed A (e.g., 155 Hz) that is lower than a predetermined rated rotation speed B (e.g., 180 Hz) in order to maintain the water pressure in the water supply pipe 3. Although it differs depending on the water pressure mode, the drive start rotation speed A is preferably set to 50 to 95% of the rated rotation speed B.

[0048] At this time, if the water flow rate detected by water volume sensor 36 remains greater than a predetermined lower limit flow rate M (e.g., 0.1 L / min) for a predetermined change determination time tm (e.g., 0.1 seconds) (Yes in step S4), the use of hot water dispensing terminal 400 is detected (step S5), and the rotational speed of water supply pressure pump 37 is immediately increased from drive start rotational speed A to rated rotational speed B (step S6). This allows hot water to be dispensed at a predetermined amount from the start of hot water dispensing. In other words, in this embodiment, the use of hot water dispensing terminal 400 is detected by water volume sensor 36 continuously detecting a flow rate greater than the predetermined lower limit flow rate M for a change determination time tm, and water volume sensor 36 functions as a use detection means.

[0049] On the other hand, when the water supply pressure pump 37 starts operating at the low rotational speed A, if the water flow rate detected by the water volume sensor 36 does not remain greater than the lower limit flow rate M for the specified change determination time tm (No in step S4), the use of the water outlet terminal 400 is not detected, and a timer is started to measure the specified rotational speed gradual increase time tc (for example, 90 seconds) for gradually increasing the rotational speed.

[0050] Then, during the rotation speed gradual increase time tc, the rotation speed of the water supply pressure pump 37 is gradually increased from the drive start rotation speed A to the rated rotation speed B according to the elapsed time, in accordance with the following equation (1) (steps S7 and S8). B'=A+{(BA)×(ti / tc)} (1) Here, B' is the elapsed rotation speed after the increase change, B is the rated rotation speed, A is the drive start rotation speed, tc is the rotation speed gradual increase time, and ti is the elapsed time.

[0051] The rotational speed of the water supply pressure pump 37 may be increased in stages from the drive start rotational speed A to the rated rotational speed B within the rotational speed gradual increase time tc.

[0052] Even during the rotation speed gradual increase time tc, the water flow rate of the water volume sensor 36 is monitored, and if the water flow rate remains greater than the lower limit flow rate M for the change determination time tm (Yes in step S4), the use of the water outlet terminal 400 is detected (step S5), and the rotation speed of the water supply pressure pump 37 is immediately increased from the elapsed rotation speed B' to the rated rotation speed B (step S6).

[0053] If the water flow rate remains greater than the lower limit flow rate M for a change judgment time tm, use of the hot water outlet terminal 400 is detected, and the water supply pressure pump 37 is operating at the rated rotation speed B, or if use of the hot water outlet terminal 400 is not detected and the rotation speed gradual increase time tc has elapsed and the rotation speed of the water supply pressure pump 37 has increased to the rated rotation speed B (step S6), it is determined whether the water flow rate detected by the water volume sensor 36 is less than the lower limit flow rate M, i.e., use of the hot water outlet terminal 400 is not detected, and the water pressure detected by the pressure sensor 35 is greater than a predetermined stop pressure D (e.g., 180 kPa) for a predetermined stop judgment time te (e.g., 120 seconds) (step S9).

[0054] If all hot water outlet terminals 400 are shut off and in an unused state, the water flow rate is below the lower limit flow rate M, no hot water outlet terminal 400 is detected in use, and the water pressure remains above the stop pressure D for the stop determination time te (Yes in step S9), the water supply pressure pump 37 is stopped, and the process returns to monitoring the drop in water pressure detected by the pressure sensor 35 (step S1). Note that if the water flow rate is greater than the lower limit flow rate M, or if the water flow rate falls below the lower limit flow rate M but does not remain below the lower limit flow rate M for the stop determination time te (No in step S9), the water supply pressure pump 37 continues to operate at the rated rotation speed B because a hot water outlet terminal 400 is in use. Also, if the water flow rate falls below the lower limit flow rate M but the water pressure detected by the pressure sensor 35 is below the stop pressure D (No in step S9), the water supply pressure pump 37 continues to operate at the rated rotation speed B to increase the water pressure in the water supply pipe 3.

[0055] As described above, according to this embodiment, when the water supply pressure booster pump 37 is stopped and the water pressure in the water supply circuit detected by the pressure sensor 35 falls below the start pressure, the water supply pressure booster pump 37 starts operating at a drive start rotation speed that is lower than the rated rotation speed, thereby reducing the load on the water supply pressure booster pump 37 when it starts operating.

[0056] Furthermore, according to this embodiment, when the operation of the water supply pressure pump 37 is started at the drive start rotation speed, if the flow rate of water flowing in the water supply circuit detected by the water volume sensor 36 is greater than the lower limit flow rate and the use of the hot water outlet terminal 400 is detected, the rotation speed of the water supply pressure pump 37 is increased from the drive start rotation speed to the rated rotation speed, so that when the hot water tap of the hot water outlet terminal 400 is opened at the start of the water supply pressure control, hot water can be immediately dispensed at a predetermined amount. This makes it possible to dispense hot water at a predetermined amount from the start of hot water dispensing, thereby improving the convenience and comfort of the user of the hot water outlet terminal 400. In particular, according to this embodiment, a water supply tank 2 is provided together with the hot water storage tank 6, and by operating the water supply pressure pump 37 provided in the water supply circuit, the water discharged from the water supply tank 2 is heated by the gas heat source units 501, 502, and hot water at a predetermined hot water outlet temperature is supplied to the hot water storage tank 6, while hot water can be supplied from the hot water storage tank 6 to the hot water outlet terminal 400.Therefore, even in areas with low water pressure, a large amount of hot water can be stably supplied to multiple hot water outlet terminals 400.

[0057] Furthermore, according to this embodiment, when the water supply pressure pump 37 is started to operate at the drive start rotation speed, if the flow rate of water flowing in the water supply circuit detected by the water volume sensor 36 is below the lower limit flow rate and the use of the hot water outlet terminal 400 is not detected, the rotation speed of the water supply pressure pump 37 is gradually increased from the drive start rotation speed to the rated rotation speed within the rotation speed gradual increase time, thereby further reducing the load when the water supply pressure pump 37 is operated with the hot water outlet terminal 400 closed.

[0058] Furthermore, according to this embodiment, when the flow rate of water flowing in the water supply circuit detected by the water volume sensor 36 becomes greater than the lower limit flow rate within the time period for gradually increasing the rotation speed and the use of the hot water outlet terminal 400 is detected, the rotation speed of the water supply pressure pump 37 is increased to the rated rotation speed. Therefore, if the hot water outlet terminal 400 is opened while the rotation speed of the water supply pressure pump 37 is gradually increasing from the start rotation speed, hot water can be immediately dispensed at the specified amount.

[0059] Furthermore, according to this embodiment, unless the water flow rate is below the lower limit flow rate, the use of hot water dispenser terminal 400 is not detected, and the water pressure remains above the stop pressure for the stop determination time, water supply pressure pump 37 will not be stopped, making it possible to accommodate frequent changes in the amount of hot water dispensed at hot water dispenser terminal 400 and prevent a decrease in the durability of water supply pressure pump 37. Furthermore, since water supply pressure pump 37 is stopped after the stop determination time has elapsed after the water pressure in the water supply circuit has risen above the stop pressure, the next time hot water is used at hot water dispenser terminal 400, hot water can be reliably dispensed at the specified amount from the start of hot water dispense.

[0060] Furthermore, according to this embodiment, when the water volume sensor 36, which is the usage detection means, detects a flow rate greater than a predetermined lower limit flow rate, it detects the use of the hot water outlet terminal 400, so that the use of the hot water outlet terminal 400 can be reliably detected.

[0061] Furthermore, the hot water supply system of this embodiment can supply hot water at a stable hot water temperature to the hot water outlet terminal, and therefore can be suitably used as a hot water supply system in facilities such as hair salons.

[0062] (Other embodiments) (1) In this embodiment, the water supply pressure pump is operated at the rated speed to increase the water pressure to the stop pressure. However, the speed at which the water pressure is increased to the stop pressure may be different from the rated speed.

[0063] (2) In the above embodiment, a water volume sensor is used as the usage detection means. However, because the water pressure detected by the pressure sensor changes depending on the usage status of the hot water outlet terminal, the pressure sensor may also be used to detect the use of the hot water outlet terminal. Specifically, when the hot water outlet terminal is not in use, the water pressure in the water supply circuit gradually decreases. On the other hand, when the hot water outlet terminal is in use, the water pressure in the water supply circuit suddenly decreases. Therefore, the use of the hot water outlet terminal can be detected by the decrease in water pressure per unit time. In this case, the pressure sensor functions as both the pressure detection means and the usage detection means. [Explanation of symbols]

[0064] 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 501,502 Gas heat source machine

Claims

1. A heating source; a hot water storage tank for storing hot water heated by a heating heat source; a heating circulation circuit that circulates hot water between the heating heat source and the hot water storage tank; A hot water supply pipe that supplies hot water from the hot water storage tank to the hot water outlet terminal; a water supply tank that receives water supplied from a water supply source; A water supply circuit that supplies water from the water supply tank to the heating heat source, hot water storage tank, and hot water outlet terminal; a water supply pressure pump provided in the water supply circuit; a pressure detection means for detecting the water pressure in the water supply circuit; A usage detection means for detecting the usage of water or hot and cold water at the hot water dispensing terminal; A control device that performs water supply pressure control to maintain the water pressure in the water supply circuit. When the water pressure in the water supply circuit falls below a predetermined operation start pressure while the water supply pressure pump is stopped, the control device starts operation of the water supply pressure pump at a predetermined drive start rotation speed that is lower than a predetermined rated rotation speed, When the water supply pressure pump is started at the drive start rotation speed, if the use of the hot water outlet terminal is detected, the rotation speed of the water supply pressure pump is increased from the drive start rotation speed to the rated rotation speed, This hot water supply system has a control configuration that gradually increases the rotation speed of the water supply pressure pump from the drive start rotation speed to the rated rotation speed within a predetermined rotation speed gradual increase time if use of the hot water outlet terminal is not detected when the water supply pressure pump is started at the drive start rotation speed.

2. The hot water supply system according to claim 1, A hot water supply system in which the control device increases the rotation speed of the water supply pressure pump to the rated rotation speed if use of the hot water outlet terminal is detected within the rotation speed gradual increase time.

3. 3. The hot water supply system according to claim 1, In this hot water supply system, the control device stops the water supply pressure pump if the use of the hot water outlet terminal is not detected and the water pressure in the water supply circuit remains at or above a predetermined stop pressure for a predetermined stop determination time while the water supply pressure pump is in operation.

4. In the hot water supply system according to any one of claims 1 to 3, The use detection means includes a water volume detection means for detecting the flow rate of water flowing through the water supply circuit, A hot water supply system that detects the use of a hot water terminal when a water volume detection means detects a flow rate greater than a predetermined lower limit flow rate.

5. In the hot water supply system according to any one of claims 1 to 4, A hot water return pipe is provided to return the hot water supplied from the hot water storage tank to the hot water outlet terminal to the hot water storage tank. This hot water supply system has an instant hot water circulation circuit that circulates hot water between a hot water storage tank and a hot water outlet terminal using a hot water supply supply pipe and a hot water return pipe.

Images