JP2020051644A - Water supply heating unit - Google Patents

Abstract

To provide a water supply heating unit capable of preventing a low water level state and water temperature drop in a hot water tank.SOLUTION: A water supply heating unit 1 includes: a condenser 42 for heating supply water CW; a compressor 4 for supplying a gas refrigerant REg to the condenser 42; a water supply pump 6 for controlling the flow rate of the supply water CW with respect to the condenser 42; a temperature sensor 8 for detecting a hot water tapping temperature of hot water HW; and a control device 9. The water supply heating unit supplies hot water HW to the hot water tank 51. The control device 9 includes: a flow rate control part 97 for controlling a water supply pump 6 so that a detection temperature value of the temperature sensor 8 becomes a target temperature value during the operation in which the compressor 4 is driven; a storage part 95 in which correlation data is stored between the water level and the target temperature value of the hot water tank 51; and a target temperature determination part 96 for determining the target temperature value based on the detection water level value of a water level sensor 50. The correlation data is the correlation in which the higher the water level of the hot water tank 51, the higher the target temperature value becomes.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a feed water heating unit.

  A technique has been proposed in which feed water is heated using heat from a heat source water and the generated hot water is supplied to a hot water tank of a boiler. By supplying the hot water from the hot water tank to the boiler, the fuel required for generating steam in the boiler is reduced. Patent Literature 1 discloses a technique relating to constant tapping temperature control for adjusting the flow rate of feedwater so that the temperature of generated hot water is maintained at a target temperature.

JP-A-2017-146033

  If the amount of generated hot water is insufficient, the hot water tank will be in a low water level near drought, and there is a concern that the operation of the boiler cannot be continued. If cold water is replenished to the hot water tank in order to eliminate the low water level state of the hot water tank, the temperature of the hot water tank decreases, and the fuel reduction effect in the boiler decreases.

  An aspect of the present invention is to provide a water supply heating unit that can prevent a low water level state and a decrease in water temperature of a hot water tank.

  According to an aspect of the present invention, there is provided a feed water heating unit for supplying hot water to a hot water tank having a water level detecting means, wherein the heat exchanger heats the feed water by heat exchange between a high-temperature fluid and the feed water; First flow switching means for switching between a flow state and a non-flow state of the high-temperature fluid with respect to the heat exchanger, flow rate adjustment means for adjusting the flow rate of water supply to the heat exchanger, and detecting a temperature of the hot water generated by the heat exchanger. Temperature control means, and control means for controlling the first flow switching means and the flow rate adjusting means, wherein the control means controls the first flow switching means to a flow state, and the temperature detection means during operation. A flow rate control unit that controls the flow rate adjusting unit so that the detected temperature value of the target temperature value becomes a target temperature value; a storage unit that stores correlation data between a water level of the hot water tank and the target temperature value; Of means A water temperature value, and a target temperature determination unit that determines the target temperature value based on the correlation data of the storage unit, wherein the correlation data is such that the higher the water level of the hot water tank, the higher the target temperature value A feedwater warming unit is provided that has a higher correlation.

  According to an aspect of the present invention, there is provided a feed water heating unit capable of preventing a low water level state and a decrease in water temperature of a hot water tank.

FIG. 1 is a schematic diagram illustrating an example of the hot water production system according to the first embodiment. FIG. 2 is a functional block diagram illustrating an example of the control device according to the first embodiment. FIG. 3 is a diagram for explaining a control method of the feedwater heating unit according to the first embodiment. FIG. 4 is a block diagram illustrating an example of the computer system according to the first embodiment. FIG. 5 is a schematic diagram illustrating an example of the heat exchanger according to the second embodiment.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings, but the present invention is not limited thereto. The components of the embodiments described below can be appropriately combined. In some cases, some components may not be used.

[1] First Embodiment <Hot water production system>
FIG. 1 is a diagram schematically illustrating an example of a hot water production system 100 according to the present embodiment. The hot water production system 100 is provided in an industrial facility such as a factory.

  The hot water production system 100 includes a feed water heating unit 1, a feed water tank 2 for storing feed water CW, a heat source water tank 3 for storing heat source water SW, and hot water for storing hot water HW generated by the feed water heating unit 1. A tank 51 and a water level sensor 50 for detecting a water level in the hot water tank 51 are provided.

  Further, the hot water production system 100 includes a water supply flow path 10 connecting the water supply tank 2 and the water supply heating unit 1, a hot water flow path 11 connecting the water supply heating unit 1 and the hot water tank 51, the water supply tank 2 and the hot water It has a bypass flow path 12 connecting the tank 51 and a heat source water flow path 13 connecting the heat source water tank 3 and the feed water heating unit 1.

  The water supply tank 2 stores the water supply CW supplied to at least one of the water supply heating unit 1 and the hot water tank 51. The water supply tank 2 is connected to the water supply heating unit 1 via a water supply flow path 10. The water supply tank 2 is connected to the hot water tank 51 via the bypass channel 12. The temperature of the feedwater CW stored in the feedwater tank 2 is, for example, 20 ° C. The feedwater CW stored in the feedwater tank 2 is soft water. Soft water from which a hardness component has been removed by a water softening device (not shown) is stored in the water supply tank 2.

  The heat source water tank 3 stores the heat source water SW supplied to the feed water heating unit 1. The heat source water tank 3 is connected to the feed water heating unit 1 via the heat source water flow path 13. The heat source water SW includes waste hot water discharged from the industrial facility. The heat source water SW is supplied from the industrial facility to the heat source water tank 3 via the supply flow path 14. The heat source water tank 3 has an overflow path 15 for causing the heat source water SW to overflow.

  The hot water tank 51 stores the hot water HW generated by the feed water heating unit 1. The hot water tank 51 is connected to the feed water heating unit 1 via the hot water flow path 11. The hot water tank 51 is connected to the boiler 52 via a hot water channel 53. A hot water pump 54 is provided in the hot water channel 53. When the hot water pump 54 is driven, the hot water HW in the hot water tank 51 is supplied to the boiler 52.

  The boiler 52 is a steam boiler. The boiler 52 heats the hot water HW supplied from the hot water tank 51 to generate steam. The steam generated by the boiler 52 is supplied to a steam-using device (not shown). By supplying the hot water HW in the hot water tank 51 to the boiler 52, the fuel required for generating steam in the boiler 52 is reduced.

  The supply passage 7 is provided in the bypass passage 12. The supply pump 7 supplies the supply water CW stored in the supply water tank 2 to the hot water tank 51. When the replenishment pump 7 is driven, the water supply CW of the water supply tank 2 is supplied to the hot water tank 51 through the bypass passage 12 without passing through the water supply heating unit 1.

  The supply pump 7 may be a variable displacement pump or a fixed displacement pump. The replenishment pump 7 switches between a distribution state in which the water supply CW is supplied to the hot water tank 51 and a non-circulation state in which the supply of the water supply CW to the hot water tank 51 is stopped. When the supply pump 7 is driven, the supply water CW is supplied from the water supply tank 2 to the hot water tank 51 so as to be in a distribution state. When the supply pump 7 is stopped, the supply water CW from the water supply tank 2 to the hot water tank 51 is stopped to be in a non-flowing state.

  The water level sensor 50 functions as a water level detection unit that detects the water level of the hot water tank 51. The water level of the hot water tank 51 refers to the height of the surface of the hot water HW stored in the hot water tank 51. In the present embodiment, the water level sensor 50 includes an electrode type water level sensor. As the water level sensor 50, for example, a plurality of electrode rods may be arranged in the hot water tank 51. The plurality of electrode rods are arranged in the hot water tank 51 such that the lower ends of the electrode rods have different heights. The water level in the hot water tank 51 is detected by specifying the electrode rod in contact with the hot water HW. The water level sensor 50 only needs to be able to detect the water level in the hot water tank 51, and may use a capacitance type water level sensor or a pressure type sensor other than the electrode type water level sensor.

<Water supply heating unit>
The feed water heating unit 1 uses the heat of the heat source water SW supplied from the heat source water tank 3 to heat the feed water CW supplied from the feed water tank 2 to generate hot water HW. The feed water heating unit 1 heats the feed water CW to generate hot water HW, a heat source water pump 5 that switches between a flow state and a non-flow state of the heat source water SW to the heat pump 4, and a feed water CW to the heat pump 4. A water supply pump 6 for adjusting the flow rate of the hot water, a temperature sensor 8 for detecting the temperature of the hot water HW generated by the heat pump 4, and a control device 9.

  The water supply pump 6 is provided in the water supply passage 10. The water supply pump 6 supplies the water supply CW stored in the water supply tank 2 to the heat pump 4. When the water supply pump 6 is driven, the water supply CW of the water supply tank 2 is supplied to the heat pump 4 via the water supply passage 10. The water supply pump 6 is a variable displacement pump. The feedwater pump 6 is capable of adjusting the flow rate of the feedwater CW to the heat pump 4.

  In the present embodiment, the drive frequency of the motor that drives the water supply pump 6 is inverter-controlled. The rotation speed of the water supply pump 6 is linked to the driving frequency of the motor. By adjusting the rotation speed of the water supply pump 6, the flow rate of the water supply CW from the water supply tank 2 to the heat pump 4 is adjusted.

  Further, the water supply pump 6 switches between a circulation state in which the water CW is supplied to the heat pump 4 and a non-circulation state in which the supply of the water CW to the heat pump 4 is stopped. When the water supply pump 6 is driven, the water supply tank 2 enters a distribution state in which the water supply CW is supplied to the heat pump 4. When the water supply pump 6 is stopped, the supply of the water CW from the water supply tank 2 to the heat pump 4 is stopped, so that a non-flow state is established.

  The heat source water pump 5 is provided in the heat source water flow path 13. The heat source water pump 5 supplies the heat source water SW stored in the heat source water tank 3 to the heat pump 4. When the heat source water pump 5 is driven, the heat source water SW of the heat source water tank 3 is supplied to the heat pump 4 via the heat source water passage 13.

  The heat source water pump 5 may be a variable displacement pump or a fixed displacement pump. The heat source water pump 5 switches between a flow state in which the heat source water SW is supplied to the heat pump 4 and a non-flow state in which the supply of the heat source water SW to the heat pump 4 is stopped. When the heat source water pump 5 is driven, the heat source water tank 3 enters a distribution state in which the heat source water SW is supplied to the heat pump 4. When the heat source water pump 5 is stopped, the supply of the heat source water SW from the heat source water tank 3 to the heat pump 4 is stopped, resulting in a non-flow state.

  In the present embodiment, the heat pump 4 is a vapor compression heat pump. The heat pump 4 has a compressor 41, a condenser 42, an expansion valve 43, and an evaporator 44. The compressor 41, the condenser 42, the expansion valve 43, and the evaporator 44 are sequentially connected in a ring shape to form a circulation flow path 47. The refrigerant RE circulates through a circulation channel 47 including the compressor 41, the condenser 42, the expansion valve 43, and the evaporator 44. The refrigerant RE flowing in the circulation flow path 47 includes a gas refrigerant REg that is a gas-phase refrigerant RE and a liquid refrigerant REl that is a liquid-phase refrigerant RE. The heat pump 4 extracts heat from the condenser 42.

  Further, the heat pump 4 has a subcooler 45 disposed between the condenser 42 and the expansion valve 43 in the circulation flow path 47, and a waste heat recovery heat exchanger 46.

  The water supply channel 10 is disposed in each of the waste heat recovery heat exchanger 46, the subcooler 45, and the condenser 42. The feedwater CW sent from the feedwater tank 2 to the feedwater flow path 10 flows through the waste heat recovery heat exchanger 46, the supercooler 45, and the condenser 42 in this order.

  The heat source water flow path 13 is disposed in each of the evaporator 44 and the waste heat recovery heat exchanger 46. The heat source water SW sent from the heat source water tank 3 to the heat source water flow path 13 flows through the evaporator 44 and the waste heat recovery heat exchanger 46 in this order.

  In the circulation flow path 47, the refrigerant RE flows in the order of the compressor 41, the condenser 42, the subcooler 45, the expansion valve 43, and the evaporator 44.

  The compressor 41 compresses the refrigerant RE. The gas refrigerant REg is supplied to the compressor 41. The compressor 41 compresses the gas refrigerant REg to generate a high-temperature and high-pressure gas refrigerant REg. The high-temperature and high-pressure gas refrigerant REg generated by the compressor 41 is a high-temperature fluid used for heat exchange with the feedwater CW.

  The compressor 41 is driven by a motor (not shown). When the compressor 41 is driven, the gas refrigerant REg is compressed, and the high-temperature and high-pressure gas refrigerant REg is supplied to the condenser 42. When the compressor 41 is stopped, the supply of the gas refrigerant REg to the condenser 42 is stopped.

  The condenser 42 condenses the gas refrigerant REg from the compressor 41. The feedwater CW is supplied to the condenser 42 via the feedwater channel 10. The gas refrigerant REg dissipates heat by being condensed in the condenser 42 and gives heat to the feedwater CW. The gas refrigerant REg is liquefied by radiating heat in the condenser 42 and is converted into the liquid refrigerant REl. The condenser 42 heats the feedwater CW by heat exchange between the gas refrigerant REg, which is a high-temperature fluid, and the feedwater CW. The condenser 42 heats the feedwater CW to generate hot water HW.

  The condenser 42 is connected to the hot water tank 51 via the hot water channel 11. The hot water HW generated by the condenser 42 is supplied to the hot water tank 51 via the hot water channel 11.

  The expansion valve 43 expands the liquid refrigerant REl from the condenser 42. The expansion valve 43 reduces the pressure and temperature of the liquid refrigerant REl from the condenser 42.

  The evaporator 44 evaporates the liquid refrigerant REl from the expansion valve 43. The heat source water SW is supplied to the evaporator 44 via the heat source water passage 13. The liquid refrigerant REl absorbs heat by evaporating in the evaporator 44 and removes heat from the heat source water SW. Further, the liquid refrigerant REl is vaporized by absorbing heat in the evaporator 44 and is converted into the gas refrigerant REg.

  The subcooler 45 is an indirect heat exchanger that exchanges heat between the feedwater CW before being supplied to the condenser 42 and the liquid refrigerant RE1 before being supplied to the expansion valve 43. The feedwater CW is supplied to the subcooler 45 via the feedwater channel 10. The liquid coolant RE1 before being supplied to the expansion valve 43 is supercooled by the supply water CW supplied to the subcooler 45. By the liquid refrigerant REl supplied to the subcooler 45, the feedwater CW before being supplied to the condenser 42 is heated. The refrigerant RE emits latent heat in the condenser 42 and emits sensible heat in the subcooler 45.

  The waste heat recovery heat exchanger 46 is an indirect heat exchanger that exchanges heat between the feedwater CW before being supplied to the subcooler 45 and the heat source water SW after passing through the evaporator 44. The feedwater CW is supplied to the waste heat recovery heat exchanger 46 via the feedwater channel 10. The heat source water SW is supplied to the waste heat recovery heat exchanger 46 via the heat source water passage 13. In the waste heat recovery heat exchanger 46, the feedwater CW and the heat source water SW exchange heat, so that the feedwater CW before being supplied to the supercooler 45 is heated.

  When the compressor 41 is driven, the gas refrigerant REg is compressed, and the high-temperature and high-pressure gas refrigerant REg, which is a high-temperature fluid, is supplied to the condenser 42. When the compressor 41 is stopped, the supply of the gas refrigerant REg to the condenser 42 is stopped. The compressor 41 functions as first flow switching means for switching between a flow state and a non-flow state of the high-temperature fluid (gas refrigerant REg) to the condenser 42. When the compressor 41 is driven, the gas refrigerant REg is supplied from the compressor 41 to the condenser 42 in a flow state. When the compressor 41 is stopped, the compressor 41 enters a non-flow state in which the supply of the gas refrigerant REg to the condenser 42 is stopped.

  The condenser 42 functions as a heat exchanger that heats the feedwater CW by exchanging heat between the high-temperature fluid (gas refrigerant REg) and the feedwater CW.

  The heat source water pump 5 functions as a second flow switching unit that switches between a flow state and a non-flow state of the heat source water SW to the evaporator 44 and the waste heat recovery heat exchanger 46. When the heat source water pump 5 is driven, the heat source water SW is supplied from the heat source water tank 3 to the evaporator 44 and the waste heat recovery heat exchanger 46 so that the heat source water SW is supplied. When the heat source water pump 5 is stopped, the supply of the heat source water SW from the heat source water tank 3 to the evaporator 44 and the waste heat recovery heat exchanger 46 is stopped, and a non-flow state is established.

  The feedwater pump 6 functions as third flow switching means for switching between a flow state and a non-flow state of the feedwater CW to the waste heat recovery heat exchanger 46, the subcooler 45, and the condenser 42. When the water supply pump 6 is driven, the wastewater recovery heat exchanger 46, the subcooler 45, and the condenser 42 are supplied with water CW from the water supply tank 2. When the feedwater pump 6 is stopped, the supply of the feedwater CW from the feedwater tank 2 to the waste heat recovery heat exchanger 46, the subcooler 45, and the condenser 42 is stopped, so that a non-flow state is established. The feedwater pump 6 adjusts the flow rate of the feedwater CW supplied to the waste heat recovery heat exchanger 46, the subcooler 45, and the condenser 42 via the feedwater flow path 10. The feedwater pump 6 functions as a flow rate adjusting unit that adjusts the flow rate of the feedwater CW to the waste heat recovery heat exchanger 46, the subcooler 45, and the condenser 42.

  Temperature sensor 8 detects the temperature of hot water CW generated in condenser 42. The temperature sensor 8 is arranged in the hot water flow path 11. The hot water flow path 11 is connected to an outlet of the condenser 42. The temperature sensor 8 functions as temperature detecting means for detecting the temperature of the hot water CW generated by the condenser 42.

  The control device 9 functions as control means for controlling the compressor 41 (first flow switching means), the heat source water pump 5 (second flow switching means), and the water supply pump 6 (third flow switching means, flow rate adjusting means). I do. The control device 9 controls each of the compressor 41, the heat source water pump 5, and the water supply pump 6. The control device 9 can switch between operation and stop of the feed water heating unit 1.

  Operating the feed water heating unit 1 includes driving at least the compressor 41. In the present embodiment, operating the feed water heating unit 1 includes driving each of the compressor 41, the heat source water pump 5, and the feed water pump 6. The control device 9 drives the compressor 41, the heat source water pump 5, and the water supply pump 6 to operate the water supply heating unit 1.

  Stopping the feed water heating unit 1 includes stopping at least the compressor 41. In the present embodiment, stopping the feed water heating unit 1 includes stopping each of the compressor 41, the heat source water pump 5, and the feed water pump 6. The control device 9 stops the compressor 41, the heat source water pump 5, and the water supply pump 6, and stops the water supply heating unit 1.

  The control device 9 links the compressor 41, the heat source water pump 5, and the water supply pump 6. When driving the compressor 41, the control device 9 also drives the heat source water pump 5 and the water supply pump 6. When stopping the compressor 41, the control device 9 also stops the heat source water pump 5 and the water supply pump 6.

  Driving the compressor 41 includes setting a circulation state in which the refrigerant RE (REg, REl) is circulated in the circulation channel 47. Stopping the compressor 41 includes bringing the compressor 41 into a non-flow state in which the circulation of the refrigerant RE in the circulation flow path 47 is stopped.

  Driving the heat source water pump 5 includes bringing the heat source water SW into a flow state in which the heat source water SW is supplied to the evaporator 44 and the waste heat recovery heat exchanger 46. Stopping the heat source water pump 5 includes bringing the heat source water SW into a non-flow state in which the supply of the heat source water SW to the evaporator 44 and the waste heat recovery heat exchanger 46 is stopped.

  Driving the feedwater pump 6 includes bringing the wastewater heat recovery heat exchanger 46, the subcooler 45, and the condenser 42 into a flow state in which the feedwater CW is supplied. Stopping the feedwater pump 6 includes bringing the wastewater heat recovery heat exchanger 46, the subcooler 45, and the condenser 42 into a non-flowing state in which the supply of the feedwater CW to the condenser 42 is stopped.

  In the present embodiment, the control device 9 controls the compressor 41, the heat source water pump 5, and the feed water pump 6 to be in a flowing state when the feed water heating unit 1 is operating, and controls the compressor 41 when the feed water heating unit 1 is stopped. , The heat source water pump 5 and the water supply pump 6 are controlled to be in a non-flowing state.

  In the present embodiment, the control device 9 controls the compressor 41 so that the output (rotational speed) of the compressor 41 becomes constant during the operation of the feed water heating unit 1. The driving frequency of the motor of the compressor 41 is kept constant, and the compressor 41 is driven with a constant output. Further, the control device 9 performs control for adjusting the opening degree of the expansion valve 43 so that the degree of superheat of the refrigerant sucked into the compressor 41 becomes constant.

<Control device>
FIG. 2 is a functional block diagram illustrating an example of the control device 9 according to the present embodiment. As shown in FIG. 2, the control device 9 includes a first flow switching control unit 91, a second flow switching control unit 92, a detected temperature obtaining unit 93, a detected water level obtaining unit 94, a storage unit 95, a target It has a temperature determiner 96, a flow controller 97, and an alarm controller 98.

  First flow switching control section 91 outputs a switching command for controlling compressor 41. The switching command output from the first distribution switching control unit 91 includes a distribution command for driving the compressor 41 to control the compressor 41 to a distribution state, and a switching instruction for stopping the compressor 41 and setting the compressor 41 to a non-circulation state. Includes non-distribution commands to control.

  The second flow switching control unit 92 outputs a switching command for controlling the heat source water pump 5. The switching command output from the second circulation switching control unit 92 includes a circulation command for driving the heat source water pump 5 to control the heat source water pump 5 to a flowing state, and a heat command water pump 5 for stopping the heat source water pump 5 and causing the heat source water pump 5 to stop. Includes a non-distribution command to control the non-distribution state.

  The heat source water pump 5 works with the compressor 41. During the operation in which the flow command is output from the first flow switching control unit 91 and the compressor 41 is controlled to the flow state, the second flow switching control unit 92 outputs the flow command to bring the heat source water pump 5 into the flow state. Control. When the non-flow command is output from the first flow switching control unit 91 and the compressor 41 is controlled to be in the non-flow state, the second flow switching control unit 92 outputs the non-flow command to stop the heat source water pump 5. Control to non-circulation state.

  The detected temperature obtaining section 93 obtains a detected temperature value of the temperature sensor 8. The temperature detected by the temperature sensor 8 is the temperature of hot water from the condenser 42, that is, the temperature of hot water supplied to the hot water tank 51.

  The detected water level obtaining unit 94 obtains a detected water level value of the water level sensor 50. The detected water level value of the water level sensor 50 corresponds to the amount of stored hot water HW in the hot water tank 51.

  The storage unit 95 stores correlation data between the water level of the hot water tank 51 and the target temperature value of the hot water HW generated by the condenser 42. The correlation data may be a correlation table or a correlation expression. The correlation data is a correlation in which the higher the water level in the hot water tank 51, the higher the target temperature value.

  The target temperature determination unit 96 determines a target temperature value of the hot water HW discharged from the condenser 42 based on the detected water level value of the water level sensor 50 acquired by the detected water level acquisition unit 94 and the correlation data of the storage unit 95. .

  During the operation of the feed water heating unit 1 that has controlled the compressor 41 to the flowing state, the flow rate control unit 97 determines the detected temperature value of the temperature sensor 8 obtained by the detected temperature obtaining unit 93 by the target temperature determining unit 96. A flow command for controlling the water supply pump 6 is output so as to reach the target temperature value.

  In the present embodiment, in the first water level state in which the detected water level value of the water level sensor 50 is lower than the upper limit water level value at which the water supply heating unit 1 is stopped, the flow rate control section 97 sets the target temperature determination section 96 to the target temperature determination section 96. The water supply pump 6 is controlled using the target temperature value determined by the control unit.

  Further, in the second water level state in which the detected water level value of the water level sensor 50 is in the second water level range lower than the first water level range, the flow control unit 97 is independent of the detected temperature value of the temperature sensor 8 and the target temperature value. The water supply pump 6 is controlled at the maximum flow rate. Controlling the feedwater pump 6 at the maximum flow rate includes performing inverter control for driving the motor of the feedwater pump 6 at the maximum drive frequency.

  Further, in the third water level state in which the detected water level value of the water level sensor 50 is in the third water level range lower than the second water level range, the flow control unit 97 controls the supply pump 7 while controlling the water supply pump 6 at the maximum flow rate. When driven, the feedwater CW flows through the bypass channel 12.

  In the first water level state and the second water level state, the flow control unit 97 stops the supply pump 7 and shuts off the flow of the feedwater CW in the bypass passage 12.

  The alarm control unit 98 is configured to control the high water level state in which the detected water level value of the water level sensor 50 is in the high water level range higher than the upper limit water level value, and the third water level state in which the detected water level value of the water level sensor 50 is in the third water level range. Activate the alarm device 16. The alarm device 16 may be an alarm sound output device that outputs an alarm sound or a display device that displays alarm display data.

<Control method>
Next, the operation of the control device 9 according to the present embodiment will be described. FIG. 3 is a diagram for explaining a control method of the feedwater heating unit 1 according to the present embodiment.

  FIG. 3 schematically shows the correlation data stored in the storage unit 95. As shown in FIG. 3, the correlation data includes a correlation table indicating a relationship between a water level of the hot water tank 51 and a target temperature value of the hot water HW discharged from the condenser 42.

  The upper limit water level is set in the correlation data. The upper limit water level value is a stop water level at which the feed water heating unit 1 is stopped. When the control device 9 determines that the detected water level value of the water level sensor 50 is in the high water level state in the high water level range higher than the upper limit water value, the control unit 9 stops the water supply heating unit 1. That is, when the flow control unit 97 determines that the detected water level value of the water level sensor 50 is in the high water level state that exceeds the upper limit water level, the flow control unit 97 stops the water supply pump 6 and stops the supply of the hot water HW to the hot water tank 51. . Further, the first flow switching control unit 91 stops the compressor 71 to stop the flow of the refrigerant RE, and the second flow switching control unit 92 stops the heat source water pump 5 to stop the supply of the heat source water SW. Let it. When determining that the detected water level value of the water level sensor 50 is higher than the upper limit water level, the alarm control unit 98 issues a high water level alarm indicating that the detected water level value is in the high water level state. Output.

  In the correlation data, a first water level range lower than the upper water level value is set. Further, a target temperature value is set in the first water level range. As shown in FIG. 3, 75 ° C., 70 ° C., 65 ° C., 60 ° C., and 55 ° C. are set as target temperature values in the first water level range. The correlation data is a correlation in which the higher the water level in the hot water tank 51, the higher the target temperature value, and the lower the water level in the hot water tank 51, the lower the target temperature value.

  In the first water level state in which the detected water level value of the water level sensor 50 is in the first water level range, the target temperature determination unit 96 is configured to perform the processing based on the detected water level value of the water level sensor 50 and the correlation data stored in the storage unit 95. , Determine the target temperature value.

  In the present embodiment, the water level for determining the target temperature value is set stepwise. As shown in FIG. 3, in the present embodiment, in the first water level range, the first water level is lower than the stop water level, the second water level is lower than the first water level, the third water level is lower than the second water level, and the third water level is lower than the second water level. A fourth water level lower than the water level and a starting water level lower than the fourth water level are set.

  For example, when it is determined that the detected water level value of the water level sensor 50 is between the stop water level and the first water level, the target temperature determination unit 96 determines the target temperature value to be 75 ° C.

  If it is determined that the detected water level value of the water level sensor 50 has transitioned from a state between the stop water level and the first water level to a state below the first water level and between the first and second water levels, the target Temperature determining section 96 determines the target temperature value to be 70 ° C.

  When it is determined that the detection water level value of the water level sensor 50 has transitioned from the state between the first water level and the second water level to a state below the second water level and between the second water level and the third water level, The target temperature determination unit 96 determines the target temperature value to be 65 ° C.

  When it is determined that the detected water level value of the water level sensor 50 has transitioned from the state between the second water level and the third water level to a state below the third water level and between the third water level and the fourth water level, The target temperature determination unit 96 determines the target temperature value to be 60 ° C.

  If it is determined that the water level value detected by the water level sensor 50 has transitioned from a state between the third water level and the fourth water level to a level below the fourth water level and between the fourth water level and the starting water level, the target Temperature determining section 96 determines the target temperature value to be 55 ° C.

  In addition, when it is determined that the detected water level value of the water level sensor 50 has transitioned from a state between the starting water level and the fourth water level to a state above the fourth water level and between the fourth and third water levels. , The target temperature determination unit 96 determines the target temperature value to be 60 ° C.

  When it is determined that the detection water level value of the water level sensor 50 has transitioned from the state between the fourth water level and the third number level to the state above the third water level and between the third water level and the second water level, The target temperature determination unit 96 determines the target temperature value to be 65 ° C.

  When it is determined that the detected water level value of the water level sensor 50 has transitioned from the state between the third water level and the second water level to the state above the second water level and between the second water level and the first water level, The target temperature determination unit 96 determines the target temperature value to be 70 ° C.

  If it is determined that the water level value detected by the water level sensor 50 has transitioned from a state between the second water level and the first water level to a level above the first water level and between the first water level and the stop water level, the target Temperature determination unit 96 determines the target temperature value to be 75 ° C.

  In the first water level state in which the water level value detected by the water level sensor 50 is in the first water level range, the flow control unit 97 controls the water supply pump 6 using the target temperature value determined by the target temperature determination unit 96. That is, when the flow rate control unit 97 determines that the detected water level value of the water level sensor 50 is in the first water level state in the first water level range, the detected temperature value of the temperature sensor 8 is determined by the target temperature determination unit 96. A constant tapping temperature control for controlling the water supply pump 6 to achieve the target temperature value is executed. In the constant tapping temperature control, an operation amount with respect to the drive frequency of the feed water pump 6 is calculated by the speed type PID algorithm so that the detected temperature value of the temperature sensor 8 converges to the target temperature value, and the output frequency from the inverter circuit to the motor unit is calculated. Is adjusted.

  When the detected water level value of the water level sensor 50 is in the first water level state, the supply pump 7 is stopped, and the flow of the feedwater CW in the bypass passage 12 is shut off.

  In the first water level state, the water supply pump 6 is controlled so that the flow rate of the hot water HW supplied to the hot water tank 5 decreases as the target temperature value increases. Further, the water supply pump 6 is controlled such that the flow rate of the hot water HW supplied to the hot water tank 51 increases as the target temperature value decreases.

  The target temperature value increases as the water level in the hot water tank 51 increases, and the target temperature value is determined based on the correlation data in which the target temperature value decreases as the water level in the hot water tank 51 decreases. The amount of generated hot water HW is increased or decreased according to the consumption speed of the hot water HW in the boiler 52. Thereby, the warm water tank 51 can be maintained in an appropriate water level range (first water level state).

  In the correlation data, a second water level range lower than the first water level range is set. The second water level range is a water level range lower than the starting water level.

  The starting water level refers to a water level at which the supply water heating unit 1 in a stopped state is started. If the detected water level value of the water level sensor 50 falls below the starting water level while the feed water heating unit 1 is stopped, the target temperature determination unit 96 determines the target temperature value to be 55 ° C., and the flow control unit 97 Then, the water supply heating unit 1 is started. The flow control unit 97 controls the water supply pump 6 so that the temperature detected by the temperature sensor 8 becomes the target temperature 55 ° C.

  During operation of the feed water heating unit 1, when it is determined that the detected water level value of the water level sensor 50 is lower than the starting water level and the water level is in the second water level state in the second water level range, the flow control unit 97 controls the water supply pump 6 to operate. Control at maximum flow rate. That is, in the second water level state in which the detected water level value of the water level sensor 50 is in the second water level range, the flow control unit 97 sets the water supply pump 6 at the maximum flow rate regardless of the detected temperature value of the temperature sensor 8 and the target temperature value. Control. In this control, the output frequency from the inverter circuit is adjusted to the maximum drive frequency.

  When the water level value detected by the water level sensor 50 is in the second water level state, the supply pump 7 is stopped, and the flow of the feedwater CW in the bypass passage 12 is cut off.

  When the water supply pump 6 is driven at the maximum drive frequency, the hot water HW is supplied to the hot water tank 51 at the maximum flow rate of the water supply pump 6. Thereby, the water level in the second water level range returns to the first water level range in a short time.

  In the correlation data, a third water level range lower than the second water level range is set. The third water level range is a water level range lower than the bypass opening water level.

  During the operation of the feed water heating unit 1, when it is determined that the detected water level value of the water level sensor 50 is lower than the bypass open water level and the state is the third water level state in the third water level range, the flow control unit 97 sets the water supply pump 6 Is controlled at the maximum flow rate, the supply pump 7 is driven to flow the feedwater CW through the bypass passage 12.

  When determining that the detected water level value of the water level sensor 50 is lower than the bypass open water level in the third water level state, the alarm control unit 98 issues a low water level alarm indicating that the detected water level value is in the third water level state. Output to the alarm device 16.

  The hot water HW and the hot water CW (cold water) are simultaneously supplied to the hot water tank 51 by driving the water supply pump 6 at the maximum drive frequency and additionally driving the supply pump 7. Thereby, the water level in the third water level range returns to the first water level range in a short time.

  When the detected water level of the hot water tank 51 transitions from the third water level state in the third water level range to the second water level state in the second water level range, the flow control unit 97 keeps controlling the water supply pump 6 at the maximum flow rate. The supply pump 7 is stopped, and the flow of the feedwater CW in the bypass passage 12 is cut off.

  In addition, when the detected water level of the hot water tank 51 has transitioned from the second water level state in the second water level range to the first water level state in the first water level range, the flow control unit 97 performs the following operations based on the target temperature value 55 ° C. The water supply pump 6 is controlled.

<Computer system>
FIG. 4 is a block diagram illustrating an example of the computer system 1000. The control device 9 described above includes a computer system 1000. The computer system 1000 includes: a processor 1001 such as a CPU (Central Processing Unit); a main memory 1002 including a nonvolatile memory such as a ROM (Read Only Memory) and a volatile memory such as a RAM (Random Access Memory); It has a storage 1003 and an interface 1004 including an input / output circuit. The functions of the control device 9 described above are stored in the storage 1003 as a program. The processor 1001 reads the program from the storage 1003, expands the program in the main memory 1002, and executes the above-described processing according to the program. Note that the program may be distributed to the computer system 1000 via a network.

<Effect>
As described above, according to the present embodiment, the correlation data between the water level of the hot water tank 51 and the target temperature value of the hot water HW is stored in the storage unit 95, and the detected water level value of the water level sensor 50 and the storage data are stored in the storage unit 95. The target temperature value of the hot water HW is determined based on the obtained correlation data. The flow rate control unit 97 controls the water supply pump 6 so that the detected temperature value of the temperature sensor 8 becomes the target temperature value during operation of the water supply heating unit 1 in which the compressor 41 and the heat source water pump 5 are in a flowing state. In the present embodiment, the correlation data is a correlation in which the higher the water level in the hot water tank 51, the higher the target temperature value. Accordingly, the hot water tank 51 is maintained at an appropriate water level and water temperature following the load of the boiler 52, and the low water level state and the decrease in the water temperature of the hot water tank 51 are prevented.

  Further, in the first water level state in which the detected water level value of the water level sensor 50 is in the first water level range, the flow control unit 97 controls the water supply pump 6 based on the target temperature value determined by the target temperature determination unit 96. As a result, a constant amount of hot water HW at a temperature at which the fuel reduction effect of the boiler 52 is obtained is continuously secured in the hot water tank 51.

  For example, when the temperature of the heat source water SW is low, it is necessary to reduce the flow rate of the feedwater CW supplied to the feedwater heating unit 1 in order to generate the hot water HW having the target temperature value. When the flow rate of the feedwater CW decreases, the amount of the hot water HW generated by the feedwater heating unit 1 may be insufficient. As a result, even when the boiler 52 is operating at a low load, the water level in the hot water tank 51 may decrease. Further, even when the boiler 52 operates at a high load and the amount of the hot water HW used suddenly increases, the water level of the hot water tank 51 may decrease.

  In the present embodiment, in the second water level state in which the detected water level value of the water level sensor 50 is in the second water level range, during operation of the feed water heating unit 1 in which the compressor 41 and the heat source water pump 5 are controlled to flow. The water supply pump 6 is controlled to the maximum flow rate. As a result, a large amount of hot water HW produced by the feed water heating unit 1 is supplied to the hot water tank 51. Therefore, the low water level state of the hot water tank 51 is reliably prevented.

  When the water supply CW of the water supply tank 2 is directly supplied from the bypass flow path 12 to the hot water tank 51 to eliminate the low water level state of the hot water tank 51, the temperature of the water supply CW of the water supply tank 2 is low. The water temperature may drop too much.

  In the present embodiment, when the water level of the hot water tank 51 falls to the second water level range, the water supply pump 6 is controlled at the maximum flow rate, and a large amount of water CW is supplied to the water heating unit 1. Although the temperature of the hot water HW generated by the feed water heating unit 1 may be lower than the target temperature value (55 ° C.), it is sufficiently higher than the temperature of the feed water CW of the feed water tank 2 (for example, 20 ° C.). By supplying a large amount of hot water HW generated by the feed water heating unit 1 to the hot water tank 51, it is possible to prevent the low water level of the hot water tank 51 and reduce the water temperature, and to obtain a fuel reduction effect in the boiler 52. it can.

  Further, in the present embodiment, in the third water level state in which the water level value detected by the water level sensor 50 is in the third water level range, during operation in which the compressor 41 and the heat source water pump 5 are controlled to flow, the water supply pump 6 The supply water CW of the water supply tank 2 is supplied to the hot water tank 51 via the bypass passage 12 while the maximum flow rate is controlled. That is, in the third water level state, a large amount of hot water HW is supplied from the feed water heating unit 1 to the hot water tank 51, and the feed water CW is supplied to the hot water tank 51 via the bypass passage 12. Thus, the lowered water level can be recovered in a short time while allowing a certain degree of water temperature reduction.

[2] Second Embodiment A second embodiment will be described. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof will be simplified or omitted.

  FIG. 5 is a schematic diagram illustrating an example of the heat exchanger 400 according to the present embodiment. In the above-described embodiment, the feedwater heating unit 1 includes the vapor compression heat pump 4, the condenser 42 is provided as a heat exchanger, and the compressor 41 is provided as first flow switching means. Further, the feedwater CW is heated by heat exchange between the gas refrigerant REg and the feedwater CW.

  As shown in FIG. 5, the feed water heating unit 1 may be provided with a heat exchanger 400 for heating the feed water CW by heat exchange between the feed water CW and the heat source water SW. Further, as first flow switching means for switching between a flowing state and a non-flowing state of the high-temperature fluid (heat source water SW) with respect to the heat exchanger 400, a heat source water capable of switching between supplying and stopping the heat source water SW to the heat exchanger 400. A pump 500 may be provided. Further, an on-off valve that can switch between supply and stop of the heat source water SW to the heat exchanger 400 may be provided as the first flow switching means.

[3] Other Embodiments In the above embodiment, the water supply pump 6 is a variable displacement pump. The water supply pump 6 may be a fixed displacement pump. When the water supply pump 6 that is a fixed displacement pump is disposed in the water supply flow path 10, a proportional control valve that functions as a flow rate adjusting unit may be disposed in the water supply flow path 10. By controlling the opening of the proportional control valve, the flow rate of the feedwater CW to the condenser 42 (the heat exchanger 400) is adjusted. During operation of the feed water heating unit 1, the proportional control valve is opened to supply the feed water CW to the condenser 42. When the feed water heating unit 1 is stopped, the proportional control valve is closed, and the feed water CW to the condenser 42 is shut off. In the first water level state, the opening of the proportional control valve is controlled such that the temperature detected by the temperature sensor 8 becomes the target temperature. In the second water level state or the third water level state, the proportional control valve is controlled so as to have the maximum opening. Thereby, the feedwater CW is supplied to the condenser 42 at the maximum flow rate.

  For example, when the heat source water SW of the heat source water tank 3 is in a pressurized state, even if the heat source water pump 5 is omitted, the heat source water SW of the heat source water tank 3 is supplied to the evaporator 44 via the heat source water passage 13. Supplied. Therefore, when the heat source water SW of the heat source water tank 3 is in a pressurized state, an on-off valve may be provided in the heat source water passage 13 as second flow switching means. By the opening / closing operation of the on-off valve, it is possible to switch between the flow state and the non-flow state of the heat source water SW to the evaporator 44 (heat exchanger 400). During operation of the feed water heating unit 1, the on-off valve is opened, and the heat source water SW is supplied to the evaporator 44. When the feed water heating unit 1 is stopped, the on-off valve is closed, and the supply of the heat source water SW to the evaporator 44 is shut off.

  DESCRIPTION OF SYMBOLS 1 ... Heating water supply unit, 2 ... Water supply tank, 3 ... Heat source water tank, 4 ... Heat pump, 5 ... Heat source water pump, 6 ... Water supply pump, 7 ... Supply pump, 8 ... Temperature sensor, 9 ... Control device, 10 ... Water supply channel, 11 hot water channel, 12 bypass channel, 13 heat source water channel, 14 supply channel, 15 overflow channel, 16 alarm device, 41 compressor, 42 condenser, 43 Expansion valve, 44 evaporator, 45 subcooler, 46 waste heat recovery heat exchanger, 47 circulation path, 50 water level sensor (water level detection means), 51 hot water tank, 52 boiler, 53 Hot water flow channel, 54 hot water pump, 91 first flow switching control unit, 92 second flow switching control unit, 93 detected temperature acquisition unit, 94 detected water level acquisition unit, 95 storage unit, 96 target temperature Determination unit, 97: flow control unit, 98: alarm control unit, 100 Hot water production system, CW ... water supply, HW ... warm water, RE ... refrigerant, REg ... gas refrigerant, REl ... liquid refrigerant, SW ... heat source water.

Claims (4)

A feed water heating unit that supplies hot water to a hot water tank having water level detection means,
A heat exchanger that heats the feedwater by heat exchange between the high-temperature fluid and the feedwater;
First flow switching means for switching between a flow state and a non-flow state of the high-temperature fluid with respect to the heat exchanger;
Flow rate adjusting means for adjusting the flow rate of feed water to the heat exchanger,
Temperature detection means for detecting the temperature of the hot water generated by the heat exchanger,
Control means for controlling the first flow switching means and the flow rate adjusting means,
The control means includes:
A flow rate control unit that controls the flow rate adjusting means so that the temperature detected by the temperature detecting means becomes a target temperature value during the operation in which the first flow switching means is controlled to a flowing state;
A storage unit that stores correlation data between the water level of the hot water tank and the target temperature value,
A target temperature determination unit that determines the target temperature value based on the detected water level value of the water level detection unit and the correlation data of the storage unit,
The correlation data is a correlation in which the higher the water level of the hot water tank, the higher the target temperature value.
Water heating unit. In the first water level state in which the detected water level value of the water level detection means is a first water level range lower than an upper limit water level value at which the water supply heating unit is stopped, the flow rate control unit determines the target temperature determination unit. The flow rate adjusting means is controlled using a target temperature value, and in a second water level state in which a detected water level value of the water level detecting means is in a second water level range lower than the first water level range, the detected temperature value and the target Controlling the flow rate adjusting means at the maximum flow rate irrespective of the temperature value,
The feed water heating unit according to claim 1. The hot water tank is connected to a bypass flow path that supplies water to the hot water tank without passing through the heat exchanger.
In the third water level state in which the detected water level value of the water level detection means is in a third water level range lower than the second water level range, the flow control unit controls the bypass flow while controlling the flow rate control means at the maximum flow rate. Circulating the water supply in the path, and in the first water level state and the second water level state, interrupts the flow of the bypass flow path;
The feed water heating unit according to claim 2. A vapor compression heat pump in which a compressor, a condenser, an expansion valve, and an evaporator are sequentially connected in a ring shape and a refrigerant is circulated, and heat is taken out by the condenser.
Second flow switching means for switching between a flow state and a non-flow state of the heat source water with respect to the evaporator,
The condenser and the compressor are provided as the heat exchanger and the first flow switching unit, respectively.
The control means controls the first flow switching means and the second flow switching means to a flow state during operation, and controls the first flow switching means and the second flow switching means to a non-flow state when stopped. ,
The feedwater heating unit according to any one of claims 1 to 3.

Images