JP7247632B2 - Hot water production system - Google Patents

Description

The present invention relates to a hot water production system.

A hot water production system is conventionally known. For example, Patent Literature 1 discloses a system for producing hot water using a heat pump for hot water washing or hot water sterilization of workpieces such as food.

JP 2009-133522 A

At present, many factories and business establishments are working on "decarbonization" to break away from fossil fuels for the purpose of reducing emissions of _CO2 , which is a typical greenhouse gas. Therefore, as disclosed in Patent Literature 1, a system using a heat pump has been increasingly adopted as a system for producing hot water. However, the COP (energy consumption efficiency ₎ of a heat pump is high if the hot water temperature is low, and the effect of reducing _CO2 emissions is also high. There is a characteristic that the reduction effect also decreases. In addition, when the hot water outlet temperature is raised, the running cost increases because the COP is low.

The present invention has been made in view of the above problems, and its object is to provide a hot water production system that is highly effective in reducing _CO2 emissions even when the outlet hot water temperature is raised, and that can also reduce running costs. to do.

In the present invention, service water is heated to a target hot water temperature while being circulated through a heat pump water heater (for example, the water heater of heat pump hot water system 10) having an electrically driven refrigerant compressor (for example, refrigerant compressor 91). 1 heating means (e.g., first heating means 2) and a steam boiler (e.g., steam boiler second heating means (e.g., second heating means 3) for directly exchanging heat with the steam generated by the device 30) to raise the temperature to a target hot water outlet temperature set higher than the target hot water supply temperature; a control means for controlling the first heating means and the second heating means, wherein the control means adjusts the output sharing between the water heater and the steam boiler in accordance with the set target hot water outlet temperature. It relates to a regulated hot water production system.

Further, the first heating means is supplied with unheated service water, and a first hot water tank (for example, the first hot water tank 40 ), a circulation line that circulates service water between the water heater and the first hot water tank, and a hot water supply temperature sensor that detects the temperature of hot water generated by the water heater, and the second heating means. is provided in a temperature-increasing steam supply line (for example, a temperature-increasing steam supply line L2) that supplies steam generated by the steam boiler to hot water generated by the water heater, and the temperature-increasing steam supply line. a temperature-increasing steam valve (e.g., temperature-increasing steam valve 54) and a second temperature sensor (e.g., second temperature sensor 241) that detects the temperature of hot water after the steam is supplied, The control means controls the water heater so that the temperature detected by the hot water supply temperature sensor becomes the target hot water supply temperature, and controls the temperature raising supply so that the temperature detected by the second temperature sensor becomes the target hot water supply temperature. It is preferable to control the degree of opening of the steam valve .

Further, the second heating means includes a second hot water tank (for example, a second hot water tank 240) to which hot water is supplied from the first hot water tank, and the temperature-raising steam supply line is provided with the second hot water tank. Preferably, the tank is supplied with steam generated by the steam boiler, and the second temperature sensor detects the temperature of hot water in the second hot water tank.

Further, the first heating means includes a first temperature sensor for detecting the temperature of hot water in the first hot water tank, and the control means controls the circulation line based on the temperature detected by the first temperature sensor. It is preferable to switch between running and stopping the circulation of service water via the .

In addition, the first heating means includes a first water level sensor (for example, a first water level sensor 42) that detects the water level in the first hot water tank, and a make-up water line ( For example, a make-up water line L5) and a make-up water valve (for example, make-up water valve 62) provided in the make-up water line. When falling below, it is preferable to open the make-up water valve.

In addition, a preheating heat exchanger (for example, a preheating heat exchanger 75) that indirectly heat-exchanges steam and water flowing through the makeup water line, and steam generated in the preheating heat exchanger by the steam boiler. and a preheating steam valve (e.g., preheating steam valve 76) provided in the preheating steam line (e.g., preheating steam line L10), Preferably , the control means opens the preheating steam supply valve when opening the makeup water valve.

In addition, a hot water pump (eg, hot water pump 243) provided in a hot water delivery line (eg, hot water delivery line 22) connecting the first hot water tank and the second hot water tank, and the water level of the second hot water tank and a second water level sensor (for example, a second water level sensor 242) that detects the water level, and the control means preferably drives the hot water pump when the water level detected by the second water level sensor falls below the set water level .

Further, the first heating means includes a first temperature sensor (for example, a first temperature sensor 41) that detects the temperature of hot water in the first hot water tank, and the first heating means includes a plurality of the Water heaters (for example, water heaters 11, 12, and 13) are included, and the first hot water tank is set with a plurality of temperature thresholds for changing the number of operating water heaters, and the control means When the temperature in the first hot water tank drops, each time the temperature detected by the first temperature sensor falls below the temperature threshold by one step, the number of water heaters in operation is increased by one. When the temperature inside the hot water tank rises, it is preferable to execute number control for decreasing the number of operating water heaters by one each time the temperature detected by the first temperature sensor exceeds the temperature threshold by one step.

In addition, a water supply tank (for example, a water supply tank 60) for storing service water to be supplied to the water heater and/or water supply to be supplied to the steam boiler, and a water supply tank for storing water to be circulated and heated by the water heater is stored water in the first hot water tank. Alternatively, it is preferable to include switching means (for example, switching means 290) for switching to the water stored in the water supply tank.

Further, the first heating means includes a first temperature sensor (for example, a first temperature sensor 41) that detects the temperature of hot water in the first hot water tank, and the first heating means includes a plurality of the Water heaters (for example, water heaters 11, 12, 13) are included, and the first hot water tank is set with a plurality of temperature thresholds for changing the number of connected water heaters, and the control means When the temperature in the first hot water tank drops, the number of water heaters connected to the first hot water tank is increased by one every time the temperature detected by the first temperature sensor falls below the temperature threshold by one step, The switching means is controlled so as to decrease the number of water heaters connected to the water supply tank one by one, and when the temperature in the first hot water tank rises, the temperature detected by the first temperature sensor exceeds the temperature threshold. The switching means is controlled so that the number of the water heaters connected to the first hot water tank is decreased by one each time the number of the water heaters is exceeded by one step, and the number of the water heaters connected to the water supply tank is increased by one. is preferred.

Further, a third temperature sensor is provided for detecting the temperature of water stored in the water supply tank, and when the temperature detected by the third temperature sensor reaches the heating stop temperature, the hot water supply during hot water supply to the water supply tank is stopped. It is preferable to stop the instrument.

In addition, the present invention heats water to a target hot water supply temperature while circulating it in a heat pump water heater (for example, the water heater of the heat pump hot water system 10) having an electrically driven refrigerant compressor (for example, the refrigerant compressor 91). and steam generated by a steam boiler having a gas-fired or oil-fired burner (e.g., steam boiler device 30) from the service water heated to the target hot water temperature in the first heating step. and a second heating step of directly exchanging heat with the hot water supply temperature to raise the temperature to a target hot water outlet temperature set higher than the target hot water supply temperature, wherein the first heating step and the second heating step are performed and a hot water production method for adjusting the output sharing between the water heater and the steam boiler in accordance with the set target hot water outlet temperature .

According to the present invention, it is possible to provide a hot water production system that is highly effective in reducing CO ₂ emissions even when the hot water temperature is raised, and is capable of reducing running costs.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic which shows the warm water production system of 1st Embodiment of this invention. It is a figure which shows the heat pump circuit of the water heater of the said embodiment. It is a functional block diagram which shows the structure of the control part of the said embodiment. It is a schematic diagram for explaining the contents of the first hot water storage control of the embodiment. It is a schematic diagram for explaining the contents of the second hot water storage control of the embodiment. FIG. 2 is a schematic diagram showing a first comparative example in which a hot water production system is constructed using only steam from a steam boiler as a heating means; FIG. 5 is a schematic diagram showing a second comparative example in which a hot water production system is constructed using only a heat pump hot water supply system as a heating means; It is a schematic diagram showing the hot water production system of the embodiment. It is a graph which shows the effect of the said embodiment. It is a schematic diagram showing a hot water production system of a second embodiment of the present invention. It is a schematic diagram showing the important part of the hot water production system of the third embodiment of the present invention. FIG. 4 is a diagram for explaining the contents of the first stored hot water temperature control of the embodiment;

<First embodiment>
A hot water production system 1 according to a first embodiment of the present invention will be described below with reference to the drawings. The term "line" used herein is a general term for lines such as channels, routes, and pipelines through which fluid can flow.

FIG. 1 is a schematic diagram showing a hot water production system 1 of this embodiment.
The hot water production system 1 of the present embodiment includes a first heating means 2 for heating the service water W1 to a first temperature while circulating it through the condenser of the heat pump water heater, and the first heating means 2. A second heating means 3 for directly heat-exchanging the water W1 with the steam S generated by the steam boiler to raise the temperature to a second temperature higher than the first temperature.

The first heating means 2 is composed of a heat pump hot water supply system 10, and includes a plurality of heat pump water heaters. A heat pump water heater 13 (hereinafter also referred to as a first water heater 11, a second water heater 12, and a third water heater 13) and a first hot water tank 40 for storing hot water, which will be described later, are provided. Heat pump water heaters 11, 12, and 13 (hereinafter also referred to as water heaters 11, 12, and 13) preferably each have an electrically driven refrigerant compressor, and heat pump water W1 in first hot water tank 40 is The water is circulated through the condenser of the hot water supply system 10 and heated to a first temperature, for example, 50-70.degree. The heat pump hot water supply system 10 and the first hot water tank 40 are circulated by a first hot water supply line L1 and a first hot water supply return line L1R that constitute a first circulation line.

Here, the plurality of water heaters 11 , 12 , 13 all have the same configuration, and all water heaters have the heat pump circuit 90 . Therefore, the heat pump circuit 90 of the first water heater 11 will be described as a representative of these.
As shown in FIG. 2 , the heat pump circuit 90 of the first water heater 11 includes a refrigerant compressor 91 , a condenser 92 , an expansion valve 93 and an evaporator 94 . The refrigerant compressor 91, the condenser 92, the expansion valve 93, and the evaporator 94 are sequentially connected in a loop by a refrigerant circulation line L7, thereby forming a heat pump circuit 90. FIG.

The electrically driven refrigerant compressor 91 has a motor 95 as a drive source, and compresses a gaseous refrigerant R such as freon gas into a high-temperature, high-pressure refrigerant. The condenser 92 condenses and liquefies the refrigerant R from the refrigerant compressor 91 . The expansion valve 93 reduces the pressure and temperature of the refrigerant R by passing the refrigerant R sent from the condenser 92 . The evaporator 94 evaporates the refrigerant R sent from the expansion valve 93 using the heat source water W8 sent through the heat source water supply line L8 as a heat source. In addition, in FIG. 1, illustration of the heat source water supply line L8 is omitted.

The heat source of the heat pump circuit 90 is not limited to heat source water such as waste hot water, but may be exhaust gas (combustion gas, exhaust steam, etc.) from factory equipment, cooling air containing waste heat, outside air not containing waste heat, or the like. Various heat source gases can be used.
In addition, in the structure of the evaporator, when the heat transfer surface is exposed to the outside, the heat source gas is supplied to the heat transfer surface by a fan (for example, ventilation of the atmosphere). Also, in the structure of the evaporator, when the heat transfer surface is present in a closed space (for example, a shell), the heat source gas is supplied to the heat transfer surface by a blower.

Thus, in the heat pump circuit 90 of the first water heater 11, the refrigerant R takes heat from the outside and vaporizes in the evaporator 94, while the refrigerant R radiates heat to the outside and condenses in the condenser 92. . Using such a principle, the heat pump circuit 90 of the first water heater 11 draws heat from the heat source water W8 in the evaporator 94, and heats the service water W1 from the first hot water tank 40 in the condenser 92. do. Then, the service water W1 heated by passing through the condenser 92 and turned into hot water is supplied again to the first hot water tank 40 through the first hot water supply line L1. Thus, the service water W1 circulates between the first hot water tank 40 and the condenser 92 of the heat pump circuit 90 .

The heat pump circuit 90 of the first water heater 11 is designed so that the degree of superheat of the refrigerant R (refrigerant temperature at the inlet of the refrigerant compressor 91) is constant, or the degree of supercooling of the refrigerant R (the refrigerant at the inlet of the expansion valve 93 The opening of the expansion valve 93 is adjusted so that the temperature) is constant.

Moreover, the output of the heat pump circuit 90 of the first water heater 11 may be changed. For example, inverter control may be used to change the rotation speed of the motor 95 of the refrigerant compressor 91 .

Each water heater 11, 12, 13 is provided with a circulation pump (not shown) for circulating the water W1. It should be noted that the circulating pump may be substantially provided in each water heater 11, 12, 13, and may be provided in the water line in each water heater 11, 12, 13. , 13 may be provided in the first hot water supply line L1 or the first hot water supply return line L1R.
The circulating pump is driven with its rotational speed adjusted, for example, by inverter control, thereby adjusting the circulating flow rate. In addition, a configuration may be employed in which a flow control valve is provided for each water heater 11, 12, 13 and the circulation flow is adjusted by controlling the opening degree of the flow control valve. When the flow control valve is provided, the circulation pump is driven at a predetermined number of revolutions (constant drive frequency).

As shown in FIG. 1 , hot water supply temperature sensors 14 , 15 , 16 for detecting the temperature of hot water supplied from each water heater 11 , 12 , 13 are provided in each of water heaters 11 , 12 , 13 . The hot water supply temperature sensors 14, 15, 16 may be substantially provided in the water heaters 11, 12, 13, and may be provided in the water heaters 11, 12, 13. , 13, and may be provided in the first hot water supply line L1 before merging.

The service water W1 heated by the plurality of water heaters 11, 12, and 13 (hereinafter also referred to as hot water W1) is supplied to the first hot water tank 40 after joining through the first hot water supply line L1. After that, the service water W1 in the first hot water tank 40 (hereinafter also referred to as hot water W1 or stored water W1) branches in the middle of the first hot water supply return line L1R, and then returns to the water heaters 11, 12, 13. .
Thus, the service water W1 circulates between the heat pump hot water supply system 10 and the first hot water tank 40 through the first hot water supply line L1 and the first hot water supply return line L1R.
As a result, the heat pump hot water supply system 10 circulates the service water W1 in the first hot water tank 40 to the condenser 92 of the heat pump circuit 90 of each of the water heaters 11, 12, and 13 while maintaining the first temperature, for example, 50 to 70. Warm to °C.

The first hot water tank 40 is a tank that stores hot water generated by circulating and heating the service water W1 through the water heaters 11 , 12 , and 13 .
The first hot water tank 40 is provided with a first temperature sensor 41 for detecting the temperature of the stored hot water W1 and a first water level sensor 42 for detecting the water level WL1 of the stored hot water W1. Then, based on the detection results of the first temperature sensor 41 and the first water level sensor 42, the first hot water storage control is performed. The details of this first hot water storage control will be described later.

The hot water production system 1 of this embodiment includes a second hot water tank 240 in addition to the first hot water tank 40 .
The first hot water tank 40 and the second hot water tank 240 are connected by a hot water delivery line L16. A hot water pump 243 for supplying the hot water W1 in the first hot water tank 40 to the second hot water tank 240 is provided in the hot water delivery line L16.
The second hot water tank 240 is provided with a second temperature sensor 241 for detecting the temperature of the stored hot water W2 and a second water level sensor 242 for detecting the water level WL2 of the stored hot water W2. Steam supply control is performed based on the detection result of the second temperature sensor 241 . Also, based on the detection result of the second water level sensor 242, the second hot water storage control is performed. In the second hot water storage control, the hot water W1 in the first hot water tank 40 is supplied into the second hot water tank 240 based on the detection result of the second water level sensor 242 . The details of these steam supply control and second hot water storage control will be described later.

Next, the second heating means 3 will be explained. The second heating means 3 includes the steam boiler device 30, the above-described second hot water tank 240, and a heating supply steam line L2 for supplying the steam S generated by the steam boiler device 30 to the second hot water tank 240. , provided.
The steam boiler device 30 is preferably a steam boiler having gas-fired or oil-fired burners, and is composed of a plurality of once-through boilers 31 that generate steam S, for example.
The second heating means 3 heats the water heated by the first heating means 2 to a second temperature higher than the first temperature using steam S generated by the steam boiler device 30 .

The temperature-increasing steam supply line L2 includes a steam header 51 in which the steam S generated by the plurality of once-through boilers 31 gathers, a connection line 52 that connects the plurality of once-through boilers 31 and the steam header 51, and the steam header 51. and a steam supply line 53 for supplying the steam S to the second hot water tank 240 . A temperature increasing steam valve 54 is provided in the steam supply line 53 . Also, the steam header 51 is provided with a pressure gauge 55 for detecting the header pressure.

The steam S from the steam boiler device 30 is supplied into the second hot water tank 240 via the steam supply line L2 for raising the temperature. As a result, the hot water W2 stored in the second hot water tank 240 (hereinafter also referred to as stored water W2) is raised to a second temperature higher than the first temperature, eg, 75 to 95.degree. That is, by blowing the steam S into the second hot water tank 240, direct heat exchange is performed between the hot water W2 stored in the second hot water tank 240 and the steam S from the steam boiler device 30. As a result, the temperature of the hot water W2 stored in the second hot water tank 240 rises. At this time, all the heat of the steam S from the steam boiler device 30, that is, the sensible heat and the latent heat are utilized by direct heat exchange, and the temperature of the hot water W2 stored in the second hot water tank 240 rises quickly.

The hot water production system 1 of this embodiment includes a water supply tank 60 that stores service water.
The service water stored in the water supply tank 60 is supplied to the steam boiler device 30 as boiler water supply via the boiler water supply line L4. A boiler water supply pump 32 is provided in the boiler water supply line L4. The boiler water supply pump 32 is driven by, for example, inverter control so that the amount of service water supplied to the steam boiler device 30 is adjusted. The boiler feedwater pump 32 may be provided for each of the plurality of once-through boilers 31 or may be provided inside the steam boiler device 30 . Also, the amount of water supply may be adjusted by a flow control valve.

Furthermore, the hot water production system 1 of the present embodiment includes a makeup water line L5 for supplying service water stored in the water supply tank 60 to the first hot water tank 40 . A makeup water pump 61 and a makeup water valve 62 are provided in the makeup water line L5. When the makeup water valve 62 is opened, the service water stored in the water supply tank 60 is supplied to the first hot water tank 40 as makeup water. At this time, cold makeup water W5 (hereinafter also referred to as service water W5 or cold water W5) is supplied into the first hot water tank 40 through the makeup water line L5. The service water W1 in the first hot water tank 40 replenished with the replenishment water W5 is circulated and heated by the heat pump hot water supply system 10 .

The hot water production system 1 of this embodiment includes a controller 100 for performing various controls. FIG. 3 is a functional block diagram showing the configuration of the control section 100. As shown in FIG. As shown in FIG. 3 , control unit 100 includes hot water supply control unit 110 , boiler control unit 120 , steam supply control unit 130 , first hot water storage control unit 140 , and second hot water storage control unit 150 .

Although the control unit 100 is composed of a plurality of functional blocks as described above, each block does not necessarily have to be physically separated. may be configured. Also, the control unit 100 may be divided into two or more units in consideration of the arrangement and wiring of the devices to be controlled. For example, from the viewpoint of independent control of water heaters and boilers, the function of the hot water supply control unit 110 is preferably incorporated into the local control unit of each water heater, and the function of the boiler control unit 120 controls a group of boilers. It is preferable to incorporate it into the number control panel.

Hot water supply control unit 110 controls heat pump hot water supply system 10 . More specifically, it controls the operation of each of the water heaters 11, 12, 13, such as execution and stoppage. Further, hot water supply control unit 110 controls circulation pumps corresponding to the respective water heaters based on the temperatures detected by hot water supply temperature sensors 14, 15, and 16, thereby supplying hot water W1 from water heaters 11, 12, and 13. Adjust the amount of hot water supply. Feedback control based on a PID algorithm is preferably used for this adjustment of the hot water supply amount.
For example, focusing on the first water heater 11, the hot water supply control unit 110 controls the rotation speed of the circulation pump so that the detected temperature detected by the hot water supply temperature sensor 14 becomes a predetermined target hot water supply temperature. Adjust the amount of hot water supply. The control of the second water heater 12 and the third water heater 13 is the same.
A flow control valve may be provided for each water heater 11, 12, 13, and the amount of hot water supplied may be adjusted by controlling the opening degree of the flow control valve.
As a result, the hot water W1 supplied from the water heaters 11, 12, and 13 is heated to the first temperature corresponding to the target hot water supply temperature so as to always reach the target hot water supply temperature.
When the amount of heat source supplied to the heat pump circuit is small, the amount of hot water supplied is reduced to control the hot water supply temperature to be maintained at the target hot water supply temperature.

As a method for controlling the hot water temperature of the water heaters 11, 12, and 13, the rotation speed of the motor 95 of the refrigerant compressor 91 is controlled so that the temperature detected by the hot water temperature sensors 14, 15, and 16 becomes the target hot water temperature. method may be adopted. As a result, the output of the refrigerant compressor 91 is gradually reduced as the temperature of the hot water stored in the first hot water tank 40 rises, thereby realizing energy-saving operation of the water heater.

Here, the target hot water supply temperature is set to 50 to 85° C., for example. More preferably, it is 50 to 70°C. This preferred target hot water supply temperature will be described later with reference to FIGS.

The boiler control unit 120 controls the number of steam boiler units 30 based on the header pressure value detected by the pressure gauge 55 provided in the steam header 51 . More specifically, the deviation amount between the header pressure value and the target steam pressure value is calculated so that the header pressure value becomes the target steam pressure value, and the number of boilers to be increased/decreased is calculated. This number increase/decrease control is known, for example, as disclosed in Japanese Unexamined Patent Application Publication No. 2015-140975, so description thereof will be omitted here.

Next, steam supply control by the steam supply control unit 130 will be described.
The steam supply control unit 130 controls the opening degree of the temperature raising steam supply valve 54 based on the temperature detected by the second temperature sensor 241 of the second hot water tank 240 . More specifically, the steam supply control unit 130 controls the opening degree of the temperature raising steam supply valve 54 so that the detected temperature detected by the second temperature sensor 241 becomes a predetermined target stored hot water temperature. to adjust the amount of steam S supplied. It is preferable to use feedback control for adjusting the amount of supply. For example, the PID algorithm calculates the operation amount for the temperature increasing steam valve 54 so that the temperature detected by the second temperature sensor 241 converges to the target hot water storage temperature, and the temperature increasing steam valve 54 is controlled by the steam supply controller 130. An opening designation signal is output to the actuator circuit of .
By performing such steam supply control, the temperature of the hot water W2 in the second hot water tank 240 is heated to the second temperature corresponding to the target stored hot water temperature so as to always reach the target stored hot water temperature.

Here, the target stored hot water temperature is higher than the target hot water supply temperature (first temperature), and is preferably set to 75 to 95°C. This preferred target stored hot water temperature will be described later with reference to FIGS.

Next, the first hot water storage control by the first hot water storage control unit 140 will be described with reference to FIG.
The first hot water storage control unit 140 controls the make-up water valve 62 based on the detection result of the first water level sensor 42 .
As shown in FIG. 4, the first water level sensor 42 is composed of an electrode-type water level detector having a plurality of electrode rods. 423 , a fourth electrode bar 424 and a fifth electrode bar 425 . Further, although not shown, an electrode rod forming a common electrode and an electrode rod for detecting an abnormal water level may be further provided.
Each of the electrode rods 421 to 425 detects whether or not the water level WL1 of the water W1 stored in the first hot water tank 40 has reached the lower end of each electrode rod, depending on whether or not the lower end thereof is submerged in water.

Here, the water level detected by the first electrode bar 421 is the water level LL, the water level detected by the second electrode bar 422 is the water level L, the water level detected by the third electrode bar 423 is the water level M, and the fourth electrode bar 424 is detected. Let H be the water level, and HH be the water level detected by the fifth electrode rod 425 . As shown in FIG. 4, the electrode bars are arranged in order from the lowest height position of the lower end to the first electrode bar 421, the second electrode bar 422, the third electrode bar 423, and the fourth electrode bar 424. , and fifth electrode rods 425 are inserted into the first hot water tank 40 .

In this embodiment, the first hot water storage controller 140 controls the supplementary water valve 62 based on the detection result of the first water level sensor 42 . For example, the first hot water storage control unit 140 opens the make-up water valve 62 when the first water level sensor 42 detects that the water level has fallen below the water level LL.

Here, the case where the water level WL1 in the first hot water tank 40 fluctuates from, for example, the range between the water level LL and the water level L shown in FIG. 4 will be described in detail.
The stored water W1 stored in the first hot water tank 40 is supplied to the second hot water tank 240 through the hot water delivery line L16. As a result, the water level WL1 in the first hot water tank 40 is lowered (see arrow A in FIG. 4).
Then, at a certain timing, when the lower end of the first electrode rod 421 is exposed from the water surface, the first water level sensor 42 detects that the water level WL1 has fallen below the water level LL.

When the first hot water storage control unit 140 detects that the water level WL1 has fallen below the water level LL, it determines that the first hot water tank 40 is in a state just before the water shortage, opens the make-up water valve 62, and stores water in the water supply tank 60. The first hot water tank 40 is replenished with the replenishing water W5 that is unheated utility water.

By performing such control, the water level WL1 recovers (see arrow B in FIG. 4).
When the water surface contacts the fifth electrode rod 425 and the tip of the fifth electrode rod 425 is immersed in the water surface, the first water level sensor 42 detects that the water level WL1 has exceeded the water level HH.
When detecting that the water level WL1 has exceeded the water level HH, the first hot water storage control unit 140 closes the supplementary water valve 62 .

With such control, when the hot water W1 in the first hot water tank 40 becomes low, the supplementary water W5 can be supplemented from the supplementary water line L5 at an appropriate timing.

In this embodiment, when the water level WL1 in the first hot water tank 40 falls below the water level LL, the make-up water valve 62 is opened to supply the make-up water W5 into the first hot water tank 40. , another water level may be used as the water level threshold to supply the make-up water W5. For example, supplementary water W5 may be supplied into the first hot water tank 40 when the water level WL1 in the first hot water tank 40 falls below the water level L. In this case, control is performed using the detection result of the second electrode rod 422 .
In this embodiment, when the water level WL1 in the first hot water tank 40 exceeds the water level HH, the supplementary water valve 62 is closed to stop the supply of the supplementary water W5. As a threshold, the supply of makeup water W5 may be stopped. For example, when the water level WL1 in the first hot water tank 40 exceeds the water level M, the supply of the make-up water W5 may be stopped. In this case, control is performed using the detection result of the third electrode rod 423 .
In this manner, the water level threshold value for performing the first hot water storage control can be selected from a plurality of water levels. As a result, the minimum amount of hot water W1 to be stored in the first hot water tank 40, the amount of replenishment water W5 to be replenished at one time, the heating time required according to the capacity of the water heater and the replenishment amount, etc. can be determined. Taking into account, the water level thresholds for starting and stopping the supply of makeup water W5 can be selected.

Then, the first hot water storage control unit 140 further executes number control for switching the number of operating water heaters 11 , 12 , 13 based on the detection result of the first temperature sensor 41 .
Specifically, as shown in FIG. 4, when the water temperature in the first hot water tank 40 rises, the number of operating water heaters is reduced by one each time the temperature detected by the first temperature sensor 41 exceeds the temperature threshold by one step. Execute the number control to decrease by increments.
Below, the case where the first target stored hot water temperature, which is the target stored hot water temperature in the first hot water tank 40, is set to 70° C., and at least 50° C. and 60° C. are set as the temperature thresholds for executing the number control. An example of

When the temperature is rising and the temperature detected by the first temperature sensor 41 is 50° C. or lower, all the three water heaters 11, 12 and 13 continue to operate.
Next, when the temperature rises and the temperature detected by the first temperature sensor 41 exceeds 50° C., one of the three water heaters stops operating, and only two water heaters continue to operate. For example, among the water heaters 11, 12, 13, the operation of the third water heater 13 is stopped, and only the first and second water heaters 11, 12 continue to operate.
Next, when the temperature further rises and the temperature detected by the first temperature sensor 41 exceeds 60° C., two of the three water heaters are stopped, and only one water heater continues to operate. For example, among the water heaters 11, 12, 13, the operation of the second and third water heaters 12, 13 is stopped, and only the first water heater 11 is kept in operation.

Then, even when the temperature further rises and the temperature detected by the first temperature sensor 41 reaches 70° C., which is the first target stored hot water temperature, the temperature in the vicinity of the first target stored hot water temperature can be maintained. Only one water heater continues to operate.
Note that when the temperature reaches the vicinity of the first target stored hot water temperature, hot water supply control unit 110 may continue to perform hot water supply temperature constant control, or may perform feedback control based on first temperature sensor 41 . That is, based on the first target stored hot water temperature and the temperature detected by the first temperature sensor 41 provided in the first hot water tank 40, feedback control of the hot water supply temperature is performed so as to maintain the temperature near the first target stored hot water temperature. may be performed. In this case, the hot water supply temperature of the water heater is adjusted in accordance with temperature fluctuations of the hot water W1 occurring in the first hot water tank 40 . The hot water supply temperature of the water heater may be adjusted by controlling the rotation speed of the motor 95 of the refrigerant compressor 91 or by controlling the rotation speed of the circulation pump of the water heater.

Then, when the temperature further rises and the temperature detected by the first temperature sensor 41 exceeds 75° C., the operation of the first water heater 11 is also stopped. That is, all the water heaters 11, 12, 13 are stopped.

Next, the case when the temperature drops will be described.
When the temperature in the first hot water tank 40 drops, the number control is executed to increase the number of operating water heaters by one each time the temperature detected by the first temperature sensor 41 falls below the temperature threshold by one step.
For example, when the temperature detected by the first temperature sensor 41 exceeds 75° C. and then falls below 70° C., only one water heater starts operating. Next, when the temperature falls below 60°C, the two water heaters are put into operation. Next, when the temperature falls below 50°C, all three water heaters are brought into operation.

In this manner, control is performed to increase or decrease the number of operating water heaters according to the temperature of the water W1 in the first hot water tank 40, so the water temperature in the first hot water tank 40 can be appropriately managed. Moreover, power consumption can be suppressed.

In addition, when switching the number of operating water heaters according to the temperature detected by the first temperature sensor 41, a state confirmation time may be provided. That is, when it is determined that the temperature detected by the first temperature sensor 41 has continued to exceed a predetermined temperature threshold for a first predetermined period of time when the temperature rises, control such as switching the number of operating water heaters is performed. It may be configured to execute. Further, when it is determined that the temperature detected by the first temperature sensor 41 has remained below the predetermined temperature threshold for the second predetermined time during the temperature drop, control such as switching the number of operating water heaters is performed. It may be configured to execute.
With such control, it is possible to perform control such as changing the number of operating water heaters based on the confirmation time of the continuation of the decrease or the confirmation time of the continuation of the rise of the detected temperature. Therefore, when the temperature detected by the first temperature sensor 41 fluctuates around the temperature threshold, it is possible to prevent the water heater from being frequently started and stopped. This reduces the risk of failure of the water heater and water supply control equipment (water supply pump, water supply valve, etc.) for hot water supply.
Further, it is preferable that the set value of the state confirmation time is adjustable. The set value of the state confirmation time can be adjusted manually or automatically, and can be set to a value greater than zero. Note that the state confirmation time is measured using an internal timer of the control unit 100 or the like.

Note that the first hot water storage control unit 140 does not set the number of operating water heaters in a predetermined temperature range to be substantially the same as shown in FIG. good.
For example, a case where the first target stored hot water temperature in the first hot water tank 40 is 70° C. to 75° C. will be described.
At this time, when the temperature is rising and the temperature detected by the first temperature sensor 41 is 60° C. or lower, all three water heaters continue to operate. When the temperature exceeds 60°C, only the two water heaters continue to operate. If the temperature exceeds 70°C, only one water heater will continue to operate. If the temperature exceeds 75°C, all three water heaters will be turned off.
On the other hand, when the temperature drops, if the temperature detected by the first temperature sensor 41 falls below 70° C., only one water heater starts operating. When the temperature drops below 60°C, the two water heaters are put into operation. When the temperature drops below 50°C, all three water heaters are put into operation.
Even with such control, when the temperature detected by the first temperature sensor 41 fluctuates around the temperature threshold, it is possible to prevent the water heater from being frequently started and stopped.

In this embodiment, the temperature of the hot water supplied from the water heaters 11, 12, and 13 is basically kept constant, except when feedback control based on the temperature detected by the first temperature sensor 41 is performed. controlled. For example, if the first target stored hot water temperature in the first hot water tank 40 is 70.degree. C., the target hot water supply temperature is set to 70.degree. C. or a temperature slightly higher than 70.degree. If the first target stored hot water temperature in the first hot water tank 40 is 75°C, the target hot water supply temperature is set to 75°C or a temperature slightly higher than 75°C, for example, 77°C. Water heaters 11, 12, and 13 supply hot water W1 at a first temperature corresponding to this target hot water supply temperature.

Note that when the hot water supply control unit 110 is incorporated in the local control unit of each water heater, the first hot water storage control unit 140 outputs a control command to the local control unit of each water heater, and upon receiving this control command, each The water heater will work.

In addition, the operation of the above water heaters is stopped by stopping the operation of the circulation pumps of the water heaters 11, 12, and 13, closing the flow control valves corresponding to the water heaters 11, 12, and 13, and the like. , and the operation of stopping the hot water supply from the water heater. It also includes stopping the driving of the refrigerant compressor 91 to stop the circulation of the refrigerant in the heat pump circuit.

It should be noted that, among the water heaters 11, 12, and 13, a configuration is adopted in which the water heater to be stopped/restarted is preferentially determined as appropriate based on the state and operation history of each water heater. may Alternatively, it may be determined in advance.

Next, the second hot water storage control by the second hot water storage control unit 150 will be described with reference to FIG.
The stored water W2 stored in the second hot water tank 240 is supplied as hot water W6 to a hot water demand location (not shown) through a hot water hot water supply line L6. As a result, the water level WL2 in the second hot water tank 240 is lowered.
In such a situation, the second hot water storage control unit 150 controls the hot water pump 243 based on the detection result of the second water level sensor 242 .
In addition, the detection water level of the second water level sensor 242 is three, water level L, water level M, and water level H, in this embodiment, and the number of detection water levels is different from that of the first water level sensor 42, but the other structure is Since it is the same as the 1st water level sensor 42, description is abbreviate|omitted here.

When the second hot water storage control unit 150 detects that the water level WL2 of the stored water W2 in the second hot water tank 240 has fallen below the water level L when the water level is falling (see arrow A in FIG. 5), the second hot water controller 150 It is determined that the water W2 stored in the tank 240 is insufficient, and the hot water pump 243 is driven. As a result, the water W1 stored in the first hot water tank 40 is supplied into the second hot water tank 240 .
At this time, the hot water W1 in the first hot water tank 40 (hot water W1 that has been heated to the first temperature by the water heater) is supplied into the second hot water tank 240, so that the hot water W1 in the second hot water tank 240 is stored. Considering that the temperature of the water W2 (the stored water W2 that has been heated to a second temperature higher than the first temperature using the steam S) will drop, the temperature-raising steam valve 54 is fully opened, As much steam S as possible is supplied to the second hot water tank 240 . At this time, the steam supply control unit 130 performs control to fully open the opening of the temperature raising steam supply valve 54 regardless of the temperature detected by the second temperature sensor 241. The temperature of the stored water W2 in 240 is raised as early as possible.

By performing such control, the water level WL2 recovers (see arrow B in FIG. 5). Then, the second water level sensor 242 detects that the water level WL2 has exceeded the water level M at a certain timing when the water level rises.
When the second hot water storage control unit 150 detects that the water level WL2 in the second hot water tank 240 has exceeded the water level M, the control of the temperature increasing steam valve 54 is changed to normal based on the temperature detected by the second temperature sensor 241. return to temperature control. At this time, the water level WL2 in the second hot water tank 240 is still not high, so the hot water pump 243 continues to operate.

Next, when the water level WL2 rises further and it is detected that the water level WL2 in the second hot water tank 240 has exceeded the water level H, it is determined that the amount of water W2 stored in the second hot water tank 240 has reached a sufficient level. , the hot water pump 243 is stopped. In addition, the control of the temperature raising steam supply valve 54 maintains the normal temperature control state by the steam supply control unit 130 .
After that, when the water level WL2 of the stored water W2 in the second hot water tank 240 drops due to the consumption of hot water by the hot water demanding point and falls below the water level L again, the hot water pump 243 is driven and the first The hot water W1 in the hot water tank 40 is supplied into the second hot water tank 240 .

With the second hot water storage control as described above, hot water can be supplied from the first hot water tank 40 to the second hot water tank 240 at an appropriate timing when the hot water W2 in the second hot water tank 240 is low. Also, the hot water temperature in the second hot water tank 240 can be appropriately controlled.

Regarding the control of the heating steam supply valve 54, a configuration in which normal temperature control is always performed based on the temperature detected by the second temperature sensor 241 regardless of the water level WL2 in the second hot water tank 240 may be adopted. good.
Incidentally, when it is detected that the water level WL2 in the second hot water tank 240 has exceeded the water level H, the temperature increasing steam valve 54 may be closed.
Note that the second hot water storage control unit 150 may control the temperature raising steam supply valve 54 via the steam supply control unit 130 .

The first water level sensor 42 and the second water level sensor 242 are not limited to electrode type water level detectors, and various water level detectors can be employed. For example, a plurality of float-type water level detectors may be provided to detect each water level threshold. Also, an electrode type water level detector and a float type water level detector may be used in combination. Furthermore, a plurality of water level thresholds may be detected using a water level detection unit such as a pressure water level sensor or a capacitance water level sensor capable of continuously measuring the water level.

As shown in this embodiment, by adopting a configuration in which hot water is circulated between the water heater and the first hot water tank 40 and steam is supplied to the second hot water tank 240, , the temperature in the vicinity of the first temperature can be maintained, and the temperature can be raised to the second temperature in the second hot water tank 240 . Therefore, hot water at the second temperature can be stably produced.

As described above, the hot water production system 1 of the present embodiment includes the first heating means 2 for heating the service water W1 to the first temperature while circulating it through the condenser of the heat pump hot water supply system 10, and the first heating means A second heating means 3 for heating the water W1 heated by the means 2 to a second temperature higher than the first temperature using steam S generated by the steam boiler device 30 .
The effect of adopting this configuration will be described in detail with reference to FIGS. 6 to 8. FIG.

FIG. 6 shows a first comparative example in which a hot water production system is constructed using only the steam S from the steam boiler device 30 as the heating means.
The temperature of hot water required by the hot water demand side varies depending on the application. Hot water may be requested. Therefore, a case will be described where the hot water production system supplies hot water in a high temperature range, for example, hot water at 90° C. to the hot water demand side.

The hot water production system 5 of FIG. 6 uses only the steam S from the steam boiler device 30 as a heating means. Here, the steam boiler has a gas-fired or oil-fired burner and uses fossil fuel to generate steam. As a result, the CO ₂ emissions and running costs of this hot water production system 5 are relatively high, and significant reductions are required.

Therefore, it is conceivable to employ a hot water production system using a heat pump type hot water supply system 10 with a high COP as a heating means.
FIG. 7 shows a second comparative example in which the hot water production system 6 is constructed using only the heat pump hot water supply system 10 as the heating means. The CO ₂ emission coefficient of electricity (0.51 kgCO ₂ /kWh) is greater than that of city gas 13A (0.18 kgCO ₂ /kWh), but when compared in terms of CO ₂ emissions _per output, COP Higher heat pumps require less than steam boilers. In addition, the electricity unit price (approximately 15 yen/kWh) is higher than the fuel unit price (approximately 6.2 yen/kWh) for city gas 13A. Cheaper than a boiler. Therefore, the hot water production system 6 has lower CO ₂ emissions and running costs than the hot water production system 5 of FIG. 6 .

_However , if the hot water supply temperature is low, the COP of the heat pump is relatively high, and the effect of reducing _CO2 emissions is high. reduction effect decreases.
For example, the COP of a heat pump when hot water of 90° C. is supplied is equivalent to 2.8 as an example. Therefore, the CO ₂ emission reduction effect (CO ₂ emission reduction ratio) is only about 10% when compared with the hot water production system 5 that uses only the steam from the steam boiler as the heating means. Also, the running cost reduction effect (running cost reduction ratio) remains at about 20%.

Next, the hot water production system 1 of the present embodiment, that is, the first heating means 2 for heating the service water W1 to the first temperature while circulating it through the condenser of the heat pump type hot water supply system 10, and the first heating means 2 and a second heating means 3 for raising the temperature of the service water W1 heated by the steam boiler device 30 to a second temperature higher than the first temperature by using the steam S generated by the steam boiler device 30. think about.

FIG. 8 shows a schematic diagram showing an outline of such a hot water production system 1. As shown in FIG.
In such a hot water production system 1, the heat pump type hot water supply system 10 as the first heating means 2 heats the water W1 to a temperature range in which it can be operated with high efficiency, for example, to 70 ° C. It is possible to raise the temperature of the hot water W1 to a high temperature range, for example, to 90° C. using the steam S from the steam boiler device 30, so that hot water in a high temperature range can be produced with high efficiency.

Here, the COP of the heat pump when the hot water supply temperature is 70° C. is, for example, equivalent to 4.2, which is extremely high. In the hot water production system 1 of this embodiment, the heat pump is in charge of heating up to a temperature range that can maintain such a high COP.
For example, when the hot water production system 1 wants to produce hot water at 90°C, the heat pump is in charge of heating up to 70°C. At this time, the heat pump takes charge of about 60% to 80% (load factor 60% to 80%) of the total heat output required to produce hot water of 90°C.
A steam boiler takes charge of raising the temperature from 70°C to 90°C. At this time, the steam boiler takes charge of about 20% to 40% (load factor of 20% to 40%) of the total heat output required to produce hot water of 90°C.

And the hot water production system 1 when using the heat pump and steam boiler in such a combination reduces CO ₂ emissions compared to the hot water production system 5 which uses only the steam from the steam boiler as a heating means. The effect is about 30%, and the reduction effect is very high. Also, the running cost reduction effect is about 35%, which is very high.

Thus, by using the hot water production system 1 of the present embodiment, it is possible to extremely effectively reduce CO ₂ emissions and running costs even when the hot water temperature is raised.
In addition, in the hot water production system 1 of the present embodiment, by appropriately adjusting the output ratio of the heat pump and the steam boiler, that is, the share of the thermal output (output sharing) of each, according to the target hot water temperature , it is possible to realize extremely effective reduction of _CO2 emissions and reduction of running costs.
It is preferable that the relationship between the output ratio of the heat pump and the steam boiler according to the target hot water outlet temperature of the hot water production system 1 is stored in a table or a calculation formula. For example, the target hot water temperature can be set, and an appropriate output ratio between the heat pump and the steam boiler is set according to the set target hot water temperature.

FIG. 9 is a graph showing the CO ₂ emission reduction ratio and the running cost reduction ratio when hot water of, for example, 90° C. is produced and discharged using the hot water production system 1 of the present embodiment.

The horizontal axis of the graph in FIG. 9 is the hot water supply temperature of the heat pump. The vertical axis of the line graph in FIG. 9 is the _CO2 emission reduction ratio and the running cost reduction ratio.
Here, the CO ₂ emission reduction ratio is reduced in the hot water production system 1 of the present embodiment when the CO ₂ emission amount of the hot water production system 5 that uses only the steam from the steam boiler as the heating means is 100%. It shows the percentage of _CO2 emissions made. That is, if the CO ₂ emission reduction ratio is 25%, it means that the conversion to the hot water production system 1 can reduce the CO ₂ emission from 100% to 75%.
On the other hand, the running cost reduction ratio is the running cost that can be reduced in the hot water production system 1 of the present embodiment when the running cost of the hot water production system 5 that uses only the steam from the steam boiler as the heating means is 100%. shows the ratio of That is, if the running cost reduction ratio is 30%, it means that the running cost of 100% can be reduced to 70% by switching to the hot water production system 1 .
The vertical axis of the bar graph in FIG. 9 indicates the output ratio between the heat pump and the steam boiler, that is, the share of thermal output (output sharing).
The COP at the hot water supply temperature of the heat pump is added to the bar graph showing the output ratio of the heat pump. The higher the hot water supply temperature, the lower the COP.

In the line graph of FIG. 9, comparing the data for heat pump hot water supply temperature = 90°C and the data for heat pump hot water supply temperature = 50°C to 80°C, it is found that when hot water of 90°C is produced using only the heat pump (heat pump hot water supply temperature = 90°C data), heating to 50 to 80°C with a heat pump and then using steam to raise the temperature to 90°C clearly has a higher _CO2 reduction effect and a running cost reduction effect. I can understand that it is expensive. For example, heating to 50 to 70°C with a heat pump and then raising the temperature to 90°C using steam will greatly reduce _CO2 and running costs.
Furthermore, from the tendency of the line graph, it should be understood that the effect of the present invention can be obtained even when the temperature is heated to 85°C by a heat pump and then heated to 90°C by using steam. can be done.

Thus, the hot water production system 1 of the present embodiment, that is, the first heating means 2 for heating the water W1 to the first temperature while circulating it through the condenser of the heat pump hot water supply system 10, and the first heating a second heating means for raising the temperature of the service water W1 heated by the means 2 to a second temperature higher than the first temperature by using the steam S generated by the steam boiler device 30; By using the system, it is possible to extremely effectively reduce _CO2 emissions and running costs even when the hot water temperature of the system is increased.

The first heating means 2 of the hot water production system 1 of the present embodiment heats the service water W1 to the first temperature while circulating it through the condenser of the heat pump water heater.
In this way, if the first heating means 2 is a circulation system, the water W1 can be efficiently supplied while reducing the water flow rate to the condenser 92 of the heat pump circuit 90 compared to the once-through (transient) system. Heating is possible, and a system with excellent running cost performance can be constructed.

The second heating means 3 of the hot water production system 1 of the present embodiment directly heat-exchanges the service water W1 heated by the first heating means 2 with the steam S generated by the steam boiler device 30, thereby The temperature is raised to a second temperature higher than the first temperature.
Thus, by directly exchanging heat between the water W1 heated by the first heating means 2 and the steam S generated by the steam boiler device 30, the water W1 heated by the first heating means 2 is Heat up quickly. That is, by utilizing all the heat (sensible heat and latent heat) of the steam S, the temperature of the water W1 heated by the first heating means 2 is rapidly increased. Therefore, control responsiveness of the outlet heated water temperature is also improved.

In order to obtain such an effect, it is particularly preferable to use a heat pump type water heater having an electrically driven refrigerant compressor as the water heater and use a steam boiler having a gas-fired or oil-fired burner as the steam boiler. preferable.
By setting the first temperature to 50 to 85° C. and the second temperature to 75° C. to 95° C., which is higher than the first temperature, the effects of the present invention can be appropriately obtained. . Preferably, the first temperature is 50 to 80°C, and the second temperature is higher than the first temperature and is 75 to 95°C. More preferably, the first temperature is 50-70°C, and the second temperature is 75-95°C.
In this way, by combining a heat pump type water heater having an electrically driven refrigerant compressor and a steam boiler having a burner that burns fossil fuels and appropriately setting the heating temperature range for each, the heat pump type water heater It is possible to obtain a high _CO2 emission reduction effect and a high running cost reduction effect as compared with the case of producing high-temperature water by using the steam boiler alone or by using the steam boiler alone.

The hot water production system 1 of the present embodiment preferably includes the second hot water tank 240 as the second heating means 3. It is also possible to employ a configuration in which steam is directly supplied to the warm water W1 in the flow path.

In order to perform appropriate hot water storage control, it is preferable to have a plurality of water heaters constituting the heat pump hot water supply system 10, but the number of water heaters may be one. In the case of one unit, the control by a plurality of water heaters described in the present embodiment is not performed, and on/off control of hot water supply based on the water temperature of the first hot water tank 40 is performed.
In addition, when using a plurality of water heaters, the number can be any number of two or more.

In addition, although it is preferable to have a plurality of boilers constituting the steam boiler device 30, the number of boilers may be one. In the case of one unit, the combustion rate may be controlled based on the measured steam pressure value and the target steam pressure value.
In addition, when using a plurality of boilers, any number of two or more can be used.
Moreover, the boiler which comprises the steam boiler apparatus 30 may be boilers other than a once-through boiler.

In addition, the hot water produced can be used for various purposes other than washing bottles for food and medicines and pasteurizer sterilization.
For example, when hot water is used in the food and beverage field, it can be used for purposes such as heating raw materials and processed products, washing bottles, and cleaning in place (CIP) of manufacturing equipment.
In addition, if steam is used in the food and beverage field, the steam S generated by the steam boiler device 30 is used for high-temperature cooking (fried food, steamed food, stir-fried food), retort pot sterilization (sterilization of pouches and canned food), and stationary production equipment. It can be used for sterilization (SIP), backup for hot water production, and the like.
And, if hot water is used in the mechanical field, it can be used for purposes such as hot water washing and degreasing.
In these applications, hot water in a high temperature range of about 75 ° C. to 95 ° C. may be required, and in the case where hot water in such a high temperature range is required, the hot water production system 1 of the present embodiment is particularly suitable. Available.

According to the hot water production system 1 of this embodiment described above, the following effects are exhibited.

(1) The hot water production system 1 of the present embodiment performs first heating in which the service water W1 is heated to a first temperature while being circulated through the condensers 92 of the heat pump water heaters 11, 12, and 13 of the heat pump hot water supply system 10. means 2, and second heating for directly heat-exchanging the water heated by the first heating means 2 with the steam S generated by the steam boiler device 30 to raise the temperature to a second temperature higher than the first temperature. means 3;
In this way, when the water is heated, the first heating means 2 heats the water to a temperature that can be heated with high efficiency by the heat pump water heaters 11, 12, and 13. Since direct heat exchange is performed, it is possible to provide a hot water production system that is highly effective in reducing CO ₂ emissions and running costs even when the hot water temperature is raised. In addition, since steam S is used for raising the temperature and direct heat exchange is performed, temperature control responsiveness is extremely good. In addition, since the first heating means is a circulation system, it is possible to efficiently heat the service water while reducing the water flow rate to the condenser 92 compared to the once-through (transient) system. You can build a system with excellent running cost performance.

(2) The water heaters 11, 12, 13 of the hot water production system 1 of the present embodiment have an electrically driven refrigerant compressor 91, the steam boiler device 30 has a gas-fired or oil-fired burner, The first temperature is 50-70°C and the second temperature is 75-95°C.
In this way, by combining a heat pump type water heater having an electrically driven refrigerant compressor and a steam boiler having a burner that burns fossil fuels and appropriately setting the heating temperature range for each, the heat pump type water heater It is possible to obtain a high _CO2 emission reduction effect and a high running cost reduction effect as compared with the case of producing high-temperature water by using the steam boiler alone or by using the steam boiler alone.

(3) The first heating means 2 of the hot water production system 1 of the present embodiment is replenished with unheated service water W5, and the water heaters 11, 12, and 13 circulate and heat the service water W5. A first hot water tank 40 for storing hot water W1 is provided, and the second heating means 3 includes a second hot water tank 240 to which hot water is supplied from the first hot water tank 40, and a steam boiler device 30 in the second hot water tank 240. A temperature-increasing steam supply line L2 for supplying the generated steam S, and a temperature-increasing steam supply valve 54 provided in the temperature-increasing steam supply line L2 are provided.
In this way, by adopting a configuration in which the hot water W1 is circulated between the water heaters 11, 12, 13 and the first hot water tank 40 and the steam S is supplied into the second hot water tank 240, the first hot water tank It is possible to maintain the temperature near the first temperature in the second hot water tank 240 and raise the temperature to the second temperature in the second hot water tank 240 . Therefore, hot water at the second temperature can be stably produced.

(4) The second heating means 3 of this embodiment includes a second temperature sensor 241 that detects the temperature of the hot water W2 in the second hot water tank 240, and the temperature detected by the second temperature sensor 241 reaches the target hot water storage temperature. The opening degree of the temperature raising steam supply valve 54 is controlled so as to
Thereby, the hot water temperature in the second hot water tank 240 can be appropriately controlled.

(5) The hot water production system 1 of the present embodiment includes a first water level sensor 42 that detects the water level WL1 in the first hot water tank 40, a makeup water line L5 that supplies water to the first hot water tank 40, a makeup water and a makeup water valve 62 provided in the line L5, and when the water level detected by the first water level sensor 42 falls below the set water level, the makeup water valve 62 is opened.
As a result, when the amount of hot water W1 in the first hot water tank 40 is low, the water W5 can be replenished from the replenishing water line L5 at an appropriate timing.

(6) In the hot water production system 1 of the present embodiment, the hot water pump 243 provided in the hot water delivery line L16 connecting the first hot water tank 40 and the second hot water tank 240 and the water level WL2 of the second hot water tank 240 and a second water level sensor 242 for detection, and drives the hot water pump 243 when the water level detected by the second water level sensor 242 falls below the set water level.
Thereby, when the hot water W2 in the second hot water tank 240 is low, hot water can be supplied from the first hot water tank 40 to the second hot water tank 240 at an appropriate timing.

(7) The hot water production system 1 of this embodiment includes a first temperature sensor 41 that detects the temperature of the hot water W1 in the first hot water tank 40, and the first heating means 2 includes a plurality of water heaters 11, 12 , 13, and a plurality of temperature thresholds are set in the first hot water tank 40 for changing the number of operating water heaters 11, 12, 13. When the temperature in the first hot water tank 40 drops, Each time the temperature detected by the temperature sensor 41 falls below the temperature threshold by one step, the number of water heaters 11, 12, and 13 in operation is increased by one. The number control is executed to decrease the number of operating water heaters 11, 12, and 13 by one each time the temperature detected by the first temperature sensor 41 exceeds the temperature threshold by one step.
Since the number of hot water heaters 11, 12, and 13 in operation is increased or decreased according to the hot water temperature in the first hot water tank 40, the hot water temperature in the first hot water tank 40 can be appropriately managed. Moreover, power consumption can be suppressed.

(8) The water heaters 11, 12, and 13 of the hot water production system 1 of the present embodiment include a refrigerant compressor 91 provided on the heat pump circuit 90, and a hot water supply temperature detector for detecting the hot water temperature of the water heaters 11, 12, and 13. and controls the rotational speed of the refrigerant compressor 91 so that the temperatures detected by the hot water supply temperature sensors 14, 15, and 16 become the target hot water supply temperature.
Thereby, the hot water temperature of the water heaters 11, 12, and 13 can be appropriately controlled.

(9) The hot water production method of the present embodiment includes a first heating step of heating service water to a first temperature while circulating it through the condensers 92 of the heat pump water heaters 11, 12, and 13, and a first heating step. and a second heating step of directly heat-exchanging the water heated in step with the steam S generated in the steam boiler device 30 to raise the temperature to a second temperature higher than the first temperature.
Thus, in heating the service water, the heat pump type water heaters 11, 12, and 13 heat the water to a temperature that can be heated with high efficiency in the first heating step, and further raise the temperature directly with the steam S. Since it is performed by exchanging heat, it is possible to provide a hot water production method that is highly effective in reducing CO ₂ emissions and running costs even when the outlet hot water temperature is raised. In addition, since steam S is used for raising the temperature and direct heat exchange is performed, temperature control responsiveness is extremely good. In addition, since the first heating process is a circulation system, it is possible to efficiently heat the service water while reducing the water flow rate to the condenser 92 compared to the once-through system, which improves running cost performance. An excellent hot water production method can be constructed.

<Second embodiment>
Next, a second embodiment will be described with reference to FIG. In addition, the description is abbreviate|omitted about the structure similar to 1st Embodiment.
The hot water production system 1 of the second embodiment further includes a preheating heat exchanger 75 for indirectly heat-exchanging the make-up water W5 flowing through the make-up water line L5 and the steam S from the steam boiler device 30 .
FIG. 10 is a diagram showing a hot water production system 1 according to a second embodiment of the invention.

As shown in FIG. 10, in this embodiment, a preheating heat exchanger 75 is provided in the make-up water line L5. The preheating heat exchanger 75 is an indirect heat exchanger, and performs indirect heat exchange between the service water (cold water) W5 from the feed water tank 60 supplied through the make-up water line L5 and the steam from the steam boiler device 30 . The preheating heat exchanger 75 is provided downstream of the make-up water valve 62 .

The steam supply line 53 (heating steam supply line L2) of the present embodiment is branched on the way, one of which is connected to the second hot water tank 240 and the other of which is connected to the preheating heat exchanger 75 . The line connected to the second hot water tank 240 is provided with a temperature raising steam valve 54 similar to that of the first embodiment. On the other hand, the line connected to the preheating heat exchanger 75 constitutes a preheating steam supply line L10, and a preheating steam supply valve 76 is provided in the preheating steam supply line L10.

These preheating heat exchanger 75, preheating steam supply line L10, and preheating steam supply valve 76 constitute additional heating means and have a function of heating makeup water W5 supplied through makeup water line L5. .

In this embodiment, the first hot water storage control unit 140 controls the preheating steam valve 76 in addition to the hot water storage control described in the first embodiment. Specifically, when the make-up water valve 62 is opened, control is performed to open the preheating steam supply valve 76 together. As a result, it is possible to prevent a rapid drop in the water temperature of the water W1 stored in the first hot water tank 40 due to the make-up water W5 supplied through the make-up water line L5.

As in the first embodiment, the makeup water valve 62 is opened when it is detected that the water level WL1 in the first hot water tank 40 has fallen below the water level LL, for example. As a result, the make-up water W5, which is cold water stored in the water supply tank 60, is supplied to the first hot water tank 40, and the water W1 stored in the first hot water tank 40 can be made up. 1 The water temperature of the water W1 stored in the hot water tank 40 is naturally lowered.

The preheating heat exchanger 75 in the present embodiment is provided to prevent the water temperature of the water W1 stored in the first hot water tank 40 from decreasing due to the replenishment of the replenishment water W5. That is, when the makeup water valve 62 is opened, the preheating steam valve 76 is also opened to heat the makeup water W5 supplied into the first hot water tank 40 through the makeup water line L5. As a result, the temperature of the makeup water W5 can be increased when the makeup water W5 is supplied from the makeup water line L5 to the first hot water tank 40 .
Therefore, when the water heater circulates and heats the water W1 in the first hot water tank 40, it can be heated to the first temperature relatively quickly.

According to the hot water production system 1 of the present embodiment described above, in addition to (1) to (9), the following effects are achieved.

(10) The hot water production system 1 of the present embodiment includes a preheating heat exchanger 75 for indirectly heat-exchanging steam with the supplementary water W5 flowing through the supplementary water line L5, and the steam boiler device 30 in the preheating heat exchanger 75. and a preheating steam supply valve 76 provided in the preheating steam supply line L10. The steam supply valve 76 is opened.
As a result, the temperature of the replenishing water can be increased when replenishing the first hot water tank 40 with service water from the replenishing water line L5.

<Third Embodiment>
Next, a third embodiment will be described with reference to FIGS. 11 and 12. FIG. In addition, the description is abbreviate|omitted about the structure similar to 1st Embodiment.
The hot water production system 1 of the third embodiment includes a switching means 290 (switching valve 291 ∼296).
FIG. 11 is a diagram showing the essential parts of the hot water production system 1 according to the third embodiment of the present invention. FIG. 4 is a schematic diagram showing a relationship with (switching valves 291 to 296).

As shown in FIG. 11, in the present embodiment, a first hot water supply line L1 and a first hot water supply return line L1 constituting a first circulation line connecting between the water heaters 11, 12, 13 and the first hot water tank 40 A line L1R, a second hot water supply line L21 and a second hot water supply return line L21R forming a second circulation line connecting between the water heaters 11, 12, 13 and the water supply tank 60 are provided.
A first hot water supply line L1, a first hot water supply return line L1R, a second hot water supply line L21, and a second hot water supply return line L21R are connected to a plurality of water heaters 11, 12, 13, respectively, as shown in FIG. It branches off along the way.

A switching valve 291 is provided on the hot water outlet side of the hot water heater 11 (the hot water outlet side). A switching valve 292 is provided on the hot water inlet side of the water heater 11 (hot water returning side). By controlling the pair of switching valves 291 and 292, the connection state in which the stored water W1 circulates between the water heater 11 and the first hot water tank 40, and the stored water between the water heater 11 and the water supply tank 60 A connection state in which W21 circulates can be switched. A connection in which the stored water W1 circulates between the water heater 11 and the first hot water tank 40 when the switching valve 291 is switched to the first hot water supply line L1 side and the switching valve 292 is switched to the first hot water supply return line L1R side. state. A connection state in which the stored water W21 circulates between the water heater 11 and the water supply tank 60 when the switching valve 291 is switched to the second hot water supply line L21 side and the switching valve 292 is switched to the second hot water supply return line L21R side. Become.

Similarly for the water heater 12, by controlling a pair of switching valves 293 and 294, a connection state in which the stored water W1 circulates between the water heater 12 and the first hot water tank 40, and a connection state in which the water heater 12 and the water supply tank are controlled. 60 can be switched between a connected state in which the stored water W21 circulates.
Similarly, for the water heater 13, by controlling a pair of switching valves 295 and 296, a connection state in which the stored water W1 circulates between the water heater 13 and the first hot water tank 40, and a connection state in which the water heater 13 and the water supply tank are controlled. 60 can be switched between a connected state in which the stored water W21 circulates.

Next, specific control contents of the switching means 290 will be described with reference to FIGS. 11 and 12. FIG.
The first hot water storage control unit 140 controls the switching valves 291 to 296 that constitute the switching means 290 based on the detection result of the first temperature sensor 41 provided in the first hot water tank 40 .

More specifically, when the water temperature in the first hot water tank 40 rises, the number of water heaters connected to the first hot water tank 40 is decreased by one each time the temperature detected by the first temperature sensor 41 exceeds the temperature threshold by one step. At the same time, the switching means 290 is controlled to increase the number of water heaters connected to the water supply tank 60 one by one.

Below, the case where the first target stored hot water temperature, which is the target stored hot water temperature in the first hot water tank 40, is set to 70° C., and at least 50° C. and 60° C. are set as the temperature thresholds for executing the number control. An example of

When the temperature detected by the first temperature sensor 41 is 50° C. or less when the temperature rises, a connection state in which the stored water W1 circulates between all the three water heaters 11, 12, and 13 and the first hot water tank 40. The switching valves 291 to 296 are controlled so that

Next, when the temperature rises and the temperature detected by the first temperature sensor 41 exceeds 50° C., only one of the three water heaters is connected to the water supply tank 60 so that the stored water W21 circulates. , controls the switching means 290 .
For example, the switching valves 295 and 296 are controlled so that only the third water heater 13 is connected to the water supply tank 60 so that the stored water W21 circulates. At this time, the first water heater 11 and the second water heater 12 continue to circulate the stored water W1 with the first hot water tank 40 .

Next, when the temperature further rises and the temperature detected by the first temperature sensor 41 exceeds 60° C., two of the three water heaters are connected to the water supply tank 60 so that the stored water W21 circulates. Thus, the switching means 290 is controlled.
For example, in addition to the third water heater 13, the switching valves 293 and 294 are controlled so that the second water heater 12 is also connected to the water supply tank 60 so that the stored water W21 circulates. At this time, the first water heater 11 continues to circulate the stored water W1 with the first hot water tank 40 .

Then, even when the temperature further rises and the temperature detected by the first temperature sensor 41 reaches 70° C., which is the first target stored hot water temperature, the temperature in the vicinity of the first target stored hot water temperature can be maintained. Only one water heater circulates the stored water W1 between it and the first hot water tank 40. - 特許庁
Note that when the temperature reaches the vicinity of the first target stored hot water temperature, the hot water supply control unit 110 may continue to perform constant control of the hot water supply temperature. Feedback control may be performed.

When the temperature further rises and the temperature detected by the first temperature sensor 41 exceeds 75° C., all three water heaters are connected to the water supply tank 60 so that the stored water W21 circulates. The switching valves 291 to 296 are controlled accordingly. As a result, the stored water W1 does not circulate between the water heater and the first hot water tank 40 .

Next, the case when the temperature drops will be described.
When the temperature in the first hot water tank 40 drops, the number of water heaters connected to the first hot water tank 40 is increased by one every time the temperature detected by the first temperature sensor 41 falls below the temperature threshold by one step. The switching means 290 is controlled so as to decrease the number of water heaters connected to the tank 60 one by one.
For example, when the temperature detected by the first temperature sensor 41 exceeds 75° C. and then falls below 70° C., only one water heater is connected to the first hot water tank 40 so that the stored water W1 circulates. , the switching means 290 is switched. Next, when the temperature detected by the first temperature sensor 41 falls below 60° C., the switching means 290 is operated so that the two water heaters are connected to the first hot water tank 40 so that the stored water W1 circulates between them. switch. Next, when the temperature detected by the first temperature sensor 41 falls below 50° C., the switching means 290 is operated so that all three water heaters are connected to the first hot water tank 40 so that the stored water W1 circulates. switch. In this control, when the number of water heaters connected to the first hot water tank 40 is increased by one, the number of water heaters connected to the water supply tank 60 is decreased by one.

In addition, when switching the switching means 290 according to the detected temperature of the first temperature sensor 41, a state confirmation time may be provided. That is, when it is determined that the temperature detected by the first temperature sensor 41 has continued to exceed the predetermined temperature threshold for the first predetermined time during the temperature rise, the switching means 290 is switched. good too. Further, when it is determined that the temperature detected by the first temperature sensor 41 has remained below the predetermined temperature threshold for the second predetermined time during the temperature drop, the switching means 290 is switched. good too.
With such control, switching control can be performed by the switching means 290 based on the confirmation time of the continuation of the decrease of the detected temperature or the confirmation time of the continuation of the increase. Therefore, when the temperature detected by the first temperature sensor 41 fluctuates in the vicinity of the temperature threshold, it is possible to prevent a situation in which switching control by the switching means 290 is frequently executed.
Further, it is preferable that the set value of the state confirmation time is adjustable. The set value of the state confirmation time can be adjusted manually or automatically, and can be set to a value greater than zero. Note that the state confirmation time is measured using an internal timer of the control unit 100 or the like.

Note that the first hot water storage control unit 140 shifts the control state of the switching means 290 in a predetermined temperature range by one step between when the temperature rises and when the temperature falls, instead of making the control state of the switching means 290 substantially the same as in FIG. good too.
For example, a case where the first target stored hot water temperature in the first hot water tank 40 is 70° C. to 75° C. will be described.
At this time, when the temperature is rising, if the temperature detected by the first temperature sensor 41 is 60° C. or less, the stored water W1 will flow between all the three water heaters 11, 12, and 13 and the first hot water tank 40. The switching valves 291 to 296 are controlled so as to establish a circulating connection state. When the temperature exceeds 60° C., the switching means 290 is controlled so that only one of the three water heaters is connected to the water supply tank 60 so that the stored water W21 circulates. When the temperature exceeds 70° C., the switching means 290 is controlled so that two of the three water heaters are connected to the water supply tank 60 so that the stored water W21 circulates.
When the temperature exceeds 75° C., the switching valves 291 to 296 are controlled so that all three water heaters are connected to the water tank 60 so that the stored water W21 circulates.

On the other hand, when the temperature drops, when the temperature detected by the first temperature sensor 41 falls below 70° C., only one water heater is connected to the first hot water tank 40 so that the stored water W1 circulates. , the switching means 290 is switched. When the temperature falls below 60° C., the switching means 290 is switched so that the two water heaters are connected to the first hot water tank 40 so that the stored water W1 circulates. When the temperature drops below 50° C., the switching means 290 is switched so that all three water heaters are connected to the first hot water tank 40 so that the stored water W1 circulates.
Even with such control, when the temperature detected by the first temperature sensor 41 fluctuates around the temperature threshold, it is possible to prevent the water heater from being frequently started and stopped.

As for the control of the hot water supply temperature of the water heater, basically the same as in the first embodiment, the hot water supply temperature constant control is performed, but feedback control based on the first temperature sensor 41 may be performed for a part of the control.

The water supply tank 60, which circulates the stored water between the water heater and the water heater, stores service water to be supplied to the water heater (supplementary water to be supplied to the first hot water tank 40) and/or water to be supplied to the steam boiler device 30. However, other water supply tanks may be used as long as they store service water that is preferably heated.

Thereby, hot water can be produced by switching the first hot water tank 40 or the water supply tank 60 according to necessity. In addition, by enabling switching, it becomes possible to continue the operation of the heat pump water heaters 11, 12, 13 as much as possible, and the problem of low-temperature water supply at the initial stage of restarting the operation of the heat pump water heaters 11, 12, 13 is solved. be able to.

A third temperature sensor is provided to detect the temperature of the water stored in the water supply tank 60, and the first hot water storage controller 140 starts supplying hot water to the water supply tank 60 when the temperature detected by the third temperature sensor reaches the heating stop temperature. may be controlled to stop the water heater.
Thereafter, when the temperature detected by the third temperature sensor drops to the heating start temperature, the operation of the water heater that has stopped supplying hot water to the water tank 60 is resumed, and control is performed to resume circulation between the water tank 60 and the water heater. you can go
Alternatively, a third water level sensor is provided to detect the water level of the water stored in the water supply tank 60, and when the water level detected by the third water level sensor reaches the heating start water level, the water heater stops supplying hot water to the water supply tank 60. Control may be performed to restart and restart the circulation between the water supply tank 60 and the water heater.
As a result, the temperature of the water stored in the water supply tank can be properly managed.

According to the hot water production system 1 of the present embodiment described above, in addition to (1) to (10), the following effects are achieved.

(11) The hot water production system 1 of the present embodiment includes a water supply tank 60 for storing service water to be supplied to the water heaters 11, 12 and 13 and/or water supply to be supplied to the steam boiler device 30, the water heaters 11, 12 and 13 and a switching means 290 for switching the circulating heating target to the stored water W1 in the first hot water tank 40 or the stored water W21 in the water supply tank 60 .
Thereby, hot water can be produced by switching the first hot water tank 40 or the water supply tank 60 according to necessity. In addition, by making it switchable, the operation of the heat pump can be continued as much as possible, and the problem of supplying low-temperature water at the initial stage of restarting the operation of the heat pump can be resolved.

(12) The hot water production system 1 of this embodiment includes a first temperature sensor 41 that detects the temperature of the hot water W1 in the first hot water tank 40, and the first heating means 2 includes a plurality of water heaters 11 and 12. , 13, and a plurality of temperature thresholds are set in the first hot water tank 40 for changing the number of connected water heaters 11, 12, 13. When the temperature in the first hot water tank 40 drops, The number of water heaters 11, 12, 13 connected to the first hot water tank 40 is increased by one each time the temperature detected by the temperature sensor 41 falls below the temperature threshold by one step, and at the same time, the number of water heaters 11, 12 to the water supply tank 60 is increased. , 13 are decreased one by one, and when the temperature inside the first hot water tank 40 rises, each time the temperature detected by the first temperature sensor 41 exceeds the temperature threshold by one step, the first 1 The switching means 290 is operated so that the number of water heaters 11, 12 and 13 connected to the hot water tank 40 is decreased by one and at the same time the number of water heaters 11, 12 and 13 connected to the water supply tank 60 is increased by one. Control.
Thereby, hot water can be produced by switching to the first hot water tank 40 or the water supply tank 260 according to necessity. In addition, by controlling the switching means 290, the operation of the heat pump can be continued as much as possible, and the problem of low-temperature water supply at the initial stage of restarting the operation of the heat pump can be resolved.

(13) The hot water production system 1 of the present embodiment includes a third temperature sensor that detects the temperature of water stored in the water supply tank 60. When the temperature detected by the third temperature sensor reaches the heating stop temperature, the water supply tank 60 Stop the water heater during hot water supply.
Thereby, the temperature of the water stored in the water supply tank 60 can be properly managed.

Although preferred embodiments of the hot water production system of the present invention have been described above, the present invention is not limited to the above-described embodiments and can be modified as appropriate. It is also possible to combine multiple embodiments.

REFERENCE SIGNS LIST 1 hot water production system 2 first heating means 3 second heating means 10 heat pump hot water supply system 11 first heat pump water heater 12 second heat pump water heater 13 third heat pump water heater 14 15, 16 Hot water temperature sensor 30 Steam boiler 31 Once-through boiler 40 First hot water tank 41 First temperature sensor 42 First water level sensor 421 First electrode bar 422 Second electrode bar 423 3 electrode rods 424 fourth electrode rod 425 fifth electrode rod 51 steam header 52 connection line 53 steam supply line 54 temperature raising steam valve 55 pressure gauge 60 water supply tank 62 supply water valve 70 Temperature control heat exchanger 71 Hot water outlet temperature sensor 72 Temperature control steam supply valve 75 Preheating heat exchanger 76 Preheating steam supply valve 80 Switching means 81, 82, 83 Switching valve 90 Heat pump circuit 91 Refrigerant compressor 92 Condenser 93 Expansion valve 94 Evaporator 100 Control section 110 Hot water supply control section 120 Boiler control section 130 Steam supply control section 140 First hot water storage control section 150 Second hot water storage control section 240 Second hot water tank 241 Second temperature sensor 242 Second water level sensor 243 Hot water pump 290 Switching means L1 First hot water supply line L1R First hot water supply return line L2 Heating steam supply line L3 Heat pump water supply Line L4 Boiler water supply line L5 Make-up water line L6 Hot water supply line L7 Refrigerant circulation line L8 Heat source water supply line L9 Temperature control steam supply line L10 Preheating steam supply line L16 Hot water delivery line L21 Second Hot water supply line L21R: Second hot water supply return line W1: Service water (hot water, stored water)
W2: Hot water (reserved water)
W5... Make-up water (service water, cold water)
W6...Hot water W21...Reserved water S...Steam R...Refrigerant WL1, WL2...Water level

Claims (12)

a first heating means for heating water to a target hot water supply temperature while circulating it through a heat pump water heater having an electrically driven refrigerant compressor ;
The service water heated to the target hot water supply temperature by the first heating means is directly heat-exchanged with steam generated by a steam boiler having a gas-fired or oil-fired burner , and set higher than the target hot water supply temperature. a second heating means for raising the temperature to the set target hot water outlet temperature;
and a control means for controlling the first heating means and the second heating means ,
The hot water production system, wherein the control means adjusts output sharing between the water heater and the steam boiler according to the set target hot water temperature. The first heating means is
a first hot water tank to which unheated service water is replenished and which stores hot water generated by circulating and heating the service water through the water heater ;
a circulation line for circulating service water between the water heater and the first hot water tank;
a hot water supply temperature sensor that detects the hot water supply temperature of hot water generated by the water heater ,
The second heating means is
a heating steam line for supplying steam generated by the steam boiler to hot water generated by the water heater ;
a temperature-increasing steam valve provided in the temperature-increasing steam supply line;
a second temperature sensor that detects the temperature of hot water after supplying the steam;
with
The control means is
controlling the water heater so that the temperature detected by the hot water supply temperature sensor becomes the target hot water supply temperature;
2. The hot water production system according to claim 1, wherein the opening degree of the temperature increasing steam valve is controlled so that the temperature detected by the second temperature sensor becomes the target hot water outlet temperature. The second heating means is
A second hot water tank to which hot water is supplied from the first hot water tank,
The temperature-raising steam supply line supplies steam generated by the steam boiler to the second hot water tank,
The hot water production system according to claim 2, wherein the second temperature sensor detects the temperature of hot water in the second hot water tank . The first heating means is
A first temperature sensor that detects the temperature of hot water in the first hot water tank,
The control means is
4. The hot water production system according to claim 2, wherein the circulation of service water through the circulation line is switched between execution and stop based on the temperature detected by the first temperature sensor. The first heating means is
a first water level sensor that detects the water level in the first hot water tank;
a makeup water line for supplying service water to the first hot water tank;
and a makeup water valve provided in the makeup water line,
The control means is
The hot water production system according to any one of claims 2 to 4 , wherein the make-up water valve is opened when the water level detected by the first water level sensor falls below a set water level. a preheating heat exchanger for indirectly heat-exchanging steam and water flowing through the make-up water line;
a preheating steam supply line for supplying the steam generated by the steam boiler to the preheating heat exchanger;
a preheating steam supply valve provided in the preheating steam supply line,
The control means is
6. The hot water production system according to claim 5, wherein the preheating steam supply valve is opened when the makeup water valve is opened. a hot water pump provided in a hot water delivery line connecting the first hot water tank and the second hot water tank;
a second water level sensor that detects the water level of the second hot water tank,
The control means is
The hot water production system according to claim 3, wherein the hot water pump is driven when the water level detected by the second water level sensor falls below a set water level. The first heating means includes a first temperature sensor that detects the temperature of hot water in the first hot water tank,
The first heating means includes a plurality of water heaters,
In the first hot water tank, a plurality of stages of temperature thresholds are set for changing the number of operating water heaters,
The control means is
When the temperature in the first hot water tank drops, each time the temperature detected by the first temperature sensor falls below the temperature threshold by one step, the number of water heaters in operation is increased by one, and
2. When the temperature inside the first hot water tank rises, the number control is executed so that the number of operating water heaters is decreased by one each time the temperature detected by the first temperature sensor exceeds the temperature threshold by one step. The hot water production system according to any one of 3 to 7. a water supply tank for storing service water to be supplied to the water heater and/or water supply to be supplied to the steam boiler;
The hot water production system according to any one of claims 3 to 7, further comprising switching means for switching the circulating heating target of the water heater to the water stored in the first hot water tank or the water stored in the water supply tank. The first heating means includes a first temperature sensor that detects the temperature of hot water in the first hot water tank,
The first heating means includes a plurality of water heaters,
Multiple stages of temperature thresholds are set in the first hot water tank for changing the number of connected water heaters,
The control means is
When the temperature in the first hot water tank drops, the number of water heaters connected to the first hot water tank is increased by one every time the temperature detected by the first temperature sensor falls below the temperature threshold by one step. , controlling the switching means so as to decrease the number of water heaters connected to the water supply tank by one;
When the temperature in the first hot water tank rises, each time the temperature detected by the first temperature sensor exceeds the temperature threshold by one step, the number of water heaters connected to the first hot water tank is decreased by one. 10. The hot water production system according to claim 9, wherein said switching means is controlled so as to increase the number of said water heaters connected to said water supply tank by one. A third temperature sensor that detects the temperature of water stored in the water supply tank,
The control means is
11. The hot water production system according to claim 9 or 10, wherein when the temperature detected by said third temperature sensor reaches a heating stop temperature, said water heater that is supplying hot water to said water supply tank is stopped. a first heating step of heating service water to a target hot water supply temperature while circulating it through a heat pump water heater having an electrically driven refrigerant compressor ;
The service water heated to the target hot water supply temperature in the first heating step is directly heat-exchanged with steam generated by a steam boiler having a gas-fired or oil-fired burner , and set higher than the target hot water supply temperature. a second heating step of raising the temperature to the set target hot water outlet temperature ;
A method for producing hot water, wherein the output sharing between the water heater and the steam boiler is adjusted according to the set target hot water outlet temperature when the first heating step and the second heating step are performed.

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