JP2015114024A - Water supply heating system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a refrigerant pressure on a discharge side from increasing excessively at start time of a compressor 13, in a water supply heating system 1 which performs adjustment of a water supply flow rate to a water supply tank 3 via a water supply passage 8 by opening adjustment of a water supply valve 10.SOLUTION: Water can be supplied to the water supply tank 3 by the water supply passage 8 via a condenser 14 of a heat pump 4. While supplying water to the water supply tank 3 via the water supply passage 8, an opening of the water supply valve 10 is adjusted so that detection temperature of a hot water tapping temperature sensor 29 is maintained at preset temperature, and the water supply flow rate to the water supply tank 3 is adjusted. When the water supply valve 10 is opened and the compressor 13 is started from a state in which the water supply valve 10 is closed and the compressor 13 is stopped, the preset temperature is decreased, the water supply valve 10 is fully opened or a supply flow rate of a heat source fluid to an evaporator 16 is limited.

Description

  The present invention relates to a feed water heating system using a heat pump.

  Conventionally, as disclosed in Patent Document 1 below, a system capable of heating water supplied to a water supply tank (3) of a boiler (2) using a heat pump (4) is known. In this system, while supplying water to the water supply tank (3) through the water supply channel (8), the heat pump (4) is operated, and the outlet water temperature of the condenser (14) of the heat pump (4) is maintained at the set temperature. Thus, typically, the feedwater pump (10) is inverter-controlled to adjust the feedwater flow rate to the feedwater tank (3) via the feedwater channel (8).

Japanese Patent No. 5263421

  The adjustment of the water supply flow rate to the water supply tank via the water supply path may be performed by adjusting the opening of the water supply valve provided in the water supply path instead of performing the inverter control of the water supply pump. For example, when water can be supplied to the water supply tank via the water supply channel by the water supply source pressure (water pressure of the water supply source), a water supply pump is not required in the water supply channel, and instead, the opening of the water supply valve provided in the water supply channel should be adjusted. It's enough.

  However, a water supply valve composed of a valve (motor valve) whose opening degree can be adjusted has a slower control response speed than a water feed pump composed of an inverter pump. Therefore, from the state where the water supply valve is closed and the compressor of the heat pump is stopped, immediately after opening the water supply valve and starting the compressor, the water flow rate of the condenser is insufficient and the refrigerant is insufficiently condensed. As a result, the refrigerant pressure on the discharge side of the compressor may exceed the upper limit value, and the compressor may be interlocked. In other words, immediately after the start of the compressor, if the flow rate of the condenser is not sufficient, condensation of the refrigerant in the condenser is not desired, the refrigerant pressure excessively increases on the discharge side of the compressor, and the compressor is forced May stop.

  Accordingly, the problem to be solved by the present invention is that in the feed water warming system in which the feed water flow rate to the feed water tank via the feed channel is adjusted by adjusting the opening of the feed valve, the refrigerant pressure on the discharge side when the compressor is started Is to prevent the excessive rise. Moreover, it makes it a subject to avoid the interlock stop of a compressor and to implement | achieve the expected driving | operation of a feed water heating system by it.

  The present invention has been made to solve the above problems, and the invention according to claim 1 is characterized in that a compressor, a condenser, an expansion valve, and an evaporator are sequentially connected in an annular manner to circulate a refrigerant, and the evaporation. A heat pump that draws heat from a heat source fluid that is passed through a condenser and heats water that is passed through the condenser, a water supply tank that can be supplied with water through the condenser, and a water supply path, A water supply valve for adjusting a water supply flow rate to the water supply tank via the water supply path, and maintaining the outlet side water temperature of the condenser at a set temperature during water supply to the water supply tank via the water supply path. Adjusting the opening of the water supply valve, closing the water supply valve and stopping the compressor, when opening the water supply valve and starting the compressor, lowering the set temperature, Whether the water supply valve exceeds the set opening A water supply warming system, characterized by the following set flow supply of source fluid to the evaporator.

  According to the first aspect of the present invention, when the feed valve is opened and the compressor is started, the set temperature is lowered, the feed valve is set to the set opening or more, or the heat source fluid is supplied to the evaporator. By setting the flow rate to be equal to or lower than the set flow rate, it is possible to prevent the refrigerant pressure on the discharge side from rising excessively when the compressor is started. And thereby, the interlock stop of a compressor can be avoided and the expected driving | operation of a feed water heating system can be implement | achieved.

  The invention according to claim 2 adjusts the opening of the water supply valve so as to maintain the outlet side water temperature of the condenser at a first set temperature during water supply to the water supply tank via the water supply channel. When opening the water supply valve and starting the compressor, a starting set temperature lower than the first set temperature is set as the set temperature until a set condition is satisfied. It is a feed water heating system of Claim 1.

  In the constant temperature control of the hot water to adjust the opening of the water supply valve so that the water temperature on the outlet side of the condenser is maintained at the set temperature during water supply to the water supply tank via the water supply channel, the feed water flow rate increases as the set temperature decreases. Can do. According to the second aspect of the present invention, when opening the water supply valve and starting the compressor, the water supply flow rate to the water supply tank via the water supply path is reduced by lowering the set temperature of the tapping temperature constant control. It is possible to ensure that the refrigerant pressure on the discharge side is not excessively increased when the compressor is started.

  The invention according to claim 3 is characterized in that, when the compressor is started while opening the water supply valve, the starting set temperature is gradually increased to the first set temperature for each set time. The feed water warming system according to claim 2.

  According to the third aspect of the present invention, when the feed valve is opened and the compressor is started, the set temperature of the tapping temperature constant control is gradually increased from a relatively low temperature, so that the water supply path is passed through. It is possible to prevent a sudden decrease in the water supply flow rate to the supplied water tank and an excessive increase in the refrigerant pressure on the discharge side of the compressor.

  In the invention according to claim 4, the initial value of the starting set temperature is a temperature obtained by adding a predetermined temperature to the water temperature of the water supply source to the water supply channel, and the predetermined temperature is equal to the water temperature of the water supply source and the water temperature. It is set in the range of 1 / 2-4 / 5 of the difference with 1st preset temperature, The feed water heating system of Claim 3 characterized by the above-mentioned.

  According to the invention described in claim 4, the set temperature at the time of starting the compressor (initial value of the set temperature for starting) is set according to the water temperature of the water supply source and the final set temperature (first set temperature). As a result, the water supply flow rate to the water supply tank via the water supply channel is ensured as desired, and the refrigerant pressure on the discharge side is prevented from excessively rising at the start of the compressor, and the water supply is heated as desired. Can be planned.

  The invention according to claim 5 is the feed water heating system according to claim 1, wherein when the compressor is started, the feed valve is fully opened when the feed valve is opened.

  According to the fifth aspect of the present invention, the supply water flow rate to the water supply tank via the water supply passage is ensured by controlling the water supply valve to be fully open when opening the water supply valve and starting the compressor. Thus, it is possible to prevent the refrigerant pressure on the discharge side from rising excessively when the compressor is started.

  The invention according to claim 6 adjusts the opening degree of the water supply valve so as to maintain the outlet side water temperature of the condenser at a first set temperature during water supply to the water supply tank via the water supply channel. When opening the water supply valve and starting the compressor, the water supply valve is fully opened, and thereafter, the opening degree of the water supply valve is decreased over time until a set condition is satisfied. It is a feed water heating system of Claim 5.

  According to invention of Claim 6, when starting a compressor while opening a water supply valve, the opening degree of a water supply valve is made small gradually from full opening, and it is to a water supply tank via a water supply channel. It is possible to prevent a sudden decrease in the feed water flow rate and an excessive increase in the refrigerant pressure on the discharge side of the compressor.

  According to a seventh aspect of the present invention, the water temperature at the outlet side of the condenser is maintained at a first set temperature while passing a heat source fluid at a predetermined flow rate through the evaporator during water supply to the water supply tank via the water supply passage. The opening degree of the water supply valve is adjusted so that the heat supply fluid is supplied from the predetermined flow rate to the evaporator until a set condition is satisfied when the water supply valve is opened and the compressor is started. The feed water heating system according to claim 1, wherein the heating water heating system is reduced to a predetermined flow rate and then gradually increased to the predetermined flow rate.

  According to the seventh aspect of the present invention, when the supply valve is opened and the compressor is started, the supply flow rate of the heat source fluid to the evaporator is gradually increased from a relatively small state, whereby the compressor It is possible to prevent an excessive increase in the refrigerant pressure on the discharge side.

  According to an eighth aspect of the present invention, when the feed valve is opened and the compressor is started, the set temperature is lowered, the feed valve is set to a set opening or more, or the heat source fluid to the evaporator The control to make the supply of the gas flow not more than the set flow rate is performed when the temperature of the heat source fluid to the evaporator exceeds the switching temperature, and is not performed when the temperature is not more than the switching temperature. The feed water heating system according to claim 1.

  According to the invention described in claim 8, when opening the feed valve and starting the compressor, the set temperature is lowered or the feed valve is turned on only when the temperature of the heat source fluid to the evaporator exceeds the switching temperature. Control is performed so that the opening is equal to or greater than the set opening, or the supply of the heat source fluid to the evaporator is equal to or less than the set flow rate. On the other hand, when the temperature of the heat source fluid to the evaporator is equal to or lower than the switching temperature, such control is not performed, so that the startup time of the feed water heating system can be shortened. Even in that case, since the temperature of the heat source fluid to the evaporator is low, there is no possibility that the refrigerant pressure on the discharge side of the compressor is excessively increased.

  The invention according to claim 9 is based on the condition that when opening the water supply valve and starting the compressor, it is first detected that the water supply valve is opened and water supply of a predetermined flow rate or more is secured. The compressor is started, and the detection is detection of whether the state can be continued until a predetermined time by opening the water supply valve until the flow rate detecting means provided in the water supply channel detects the predetermined flow rate. It is a feed water heating system of any one of Claims 1-8 characterized by the above-mentioned.

  According to the ninth aspect of the present invention, it is possible to prevent an excessive increase in the refrigerant pressure on the discharge side of the compressor due to a shortage of the feed water flow rate by confirming the presence or absence of feed water of a predetermined flow rate or higher before starting the compressor. Moreover, the confirmation can be performed with simple control.

  Furthermore, the invention described in claim 10 includes a waste heat recovery heat exchanger that exchanges heat between the water in the water supply channel upstream of the condenser and the heat source fluid after passing through the evaporator. The presence or absence of water supply to the water supply tank via a channel is switched based on the water level of the water supply tank, and the water temperature to the water supply tank via the water supply channel is such that the temperature of the heat source fluid to the evaporator is below a specified temperature. If so, the opening degree of the water supply valve is adjusted so as to maintain the outlet side water temperature of the condenser at the first set temperature in a state where the heat pump is operated, and to the water tank via the water supply path. When the temperature of the heat source fluid to the evaporator becomes equal to or higher than a specified temperature during the water supply, the outlet water temperature of the condenser is maintained at a second preset temperature lower than the first preset temperature while the heat pump is stopped. The opening of the water supply valve A water supply warming system according to any one of claims 1-9, characterized in that the integer.

  According to the invention described in claim 10, if the heat source fluid temperature to the evaporator is lower than the specified temperature, the outlet water temperature of the condenser is maintained at the first set temperature while the heat pump is operated. Regardless of the water temperature of the water supply source or the temperature of the heat source fluid, hot water having a desired temperature can be obtained by adjusting the opening of the water supply valve. On the other hand, when the heat source fluid temperature to the evaporator becomes equal to or higher than the specified temperature, the heat pump is stopped, so that the compressor can be protected. However, even in that case, heat recovery from the heat source fluid can be achieved by exchanging heat between the water supply and the heat source fluid in the waste heat recovery heat exchanger. In addition, by switching the set temperature of the hot water temperature constant control to the second set temperature that is lower than the first set temperature, the water supply flow rate to the water supply tank via the water supply channel is ensured to a certain extent, and the heat source fluid Heat recovery can be effectively achieved.

  According to the present invention, in the feed water heating system that adjusts the feed water flow rate to the feed water tank via the feed water channel by adjusting the opening of the feed valve, the refrigerant pressure on the discharge side excessively rises when the compressor is started. Can be prevented. In addition, thereby, it is possible to avoid the interlock stop of the compressor and to realize the expected operation of the feed water heating system.

It is the schematic which shows one Example of the feed water heating system of this invention.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic view showing an embodiment of a feed water warming system 1 of the present invention.

  The feed water warming system 1 of the present embodiment is a system that can heat the feed water to the feed water tank 3 of the boiler 2 with the heat pump 4. The feed water tank 3 that stores the feed water to the boiler 2, and the feed water tank 3 A heat pump 4 for warming water supply and a heat source water tank 5 for storing heat source water (for example, waste warm water) as a heat source of the heat pump 4 are provided.

  The boiler 2 is a steam boiler, and heats the feed water from the feed water tank 3 into steam. The boiler 2 is typically adjusted in combustion quantity so as to maintain the desired steam pressure. Further, the boiler 2 is controlled by a water supply path from the water supply tank 3 to the boiler 2 or a pump 6 provided in the boiler 2 so as to maintain a desired water level in the can. The steam from the boiler 2 is sent to various steam use facilities (not shown), but drain (condensed water of steam) from the steam use facility may be returned to the water supply tank 3. Alternatively, the drain from the steam using facility may be supplied to the heat source water tank 5.

  In the present embodiment, the water supply tank 3 is supplied with water (soft water) from which the water hardness has been removed in the water softening device 7. The water supply tank 3 can be supplied with water from the soft water device 7 through the heat pump 4 through the water supply channel 8 and can be supplied through the replenishment water channel 9 without using the heat pump 4. The water supply channel 8 and the replenishment channel 9 are common pipes on the soft water device 7 side. By controlling the water supply valve 10 provided in the water supply channel 8 and the makeup water valve 11 provided in the makeup water channel 9, water is supplied to the water supply tank 3 through one or both of the water supply channel 8 and the makeup water channel 9. Is possible.

  When the water supply valve 10 is opened, water from the soft water device 7 can be supplied to the water supply tank 3 through the water supply path 8 by the water supply source pressure (water pressure of the water supply source). On the other hand, when the make-up water valve 11 is opened, water from the soft water device 7 can be fed to the feed water tank 3 through the make-up water channel 9 by the feed water source pressure. In addition, it is preferable to provide the water supply valve 10 in the upstream of the waste heat recovery heat exchanger 12 mentioned later in the water supply path 8. FIG.

  The water supply valve 10 is composed of a motorized valve such as a motor valve whose opening degree can be adjusted. By adjusting the opening degree of the water supply valve 10, the water supply flow rate to the water supply tank 3 through the water supply path 8 can be adjusted. On the other hand, the makeup water valve 11 is constituted by an electric valve or an electromagnetic valve. By switching the opening and closing of the replenishing water valve 11, it is possible to switch the presence or absence of water supply to the water supply tank 3 via the replenishing water channel 9.

  The heat pump 4 is a vapor compression heat pump, and is configured by sequentially connecting a compressor 13, a condenser 14, an expansion valve 15, and an evaporator 16 in an annular shape. The compressor 13 compresses the gas refrigerant to a high temperature and a high pressure. The condenser 14 condenses and liquefies the gas refrigerant from the compressor 13. Further, the expansion valve 15 allows the liquid refrigerant from the condenser 14 to pass through, thereby reducing the pressure and temperature of the refrigerant. The evaporator 16 then evaporates the refrigerant from the expansion valve 15.

  Therefore, in the heat pump 4, in the evaporator 16, the refrigerant takes heat from the outside and vaporizes, while in the condenser 14, the refrigerant dissipates heat to the outside and condenses. Using this, in this embodiment, the heat pump 4 draws heat from the heat source water in the evaporator 16, and heats the water in the water supply path 8 in the condenser 14.

  It is preferable that the heat pump 4 further includes a supercooler 17 between the condenser 14 and the expansion valve 15. The supercooler 17 is an indirect heat exchanger between the water in the water supply channel 8 upstream of the condenser 14 and the refrigerant from the condenser 14 to the expansion valve 15. The subcooler 17 can supercool the refrigerant from the condenser 14 to the expansion valve 15 by supplying water to the condenser 14, and can supply the refrigerant to the condenser 14 by the refrigerant from the condenser 14 to the expansion valve 15. The water supply can be heated. The refrigerant of the heat pump 4 preferably releases latent heat in the condenser 14 and releases sensible heat in the subcooler 17.

  That is, in the condenser 14, the gas refrigerant is condensed into a liquid refrigerant, and the liquid refrigerant is supplied to the subcooler 17, and the liquid refrigerant is further cooled (supercooled) in the subcooler 17. By separating heat exchangers for refrigerant condensation and supercooling, the heat exchanger can be easily designed, the heat exchanger can be reduced in size with a simple structure, and costs can be reduced. In addition, a general-purpose heat exchanger can be used.

  In addition, in the heat pump 4, an accumulator is installed on the inlet side of the compressor 13, an oil separator is installed on the outlet side of the compressor 13, or the outlet side of the condenser 14 (the condenser 14 and the subcooler 17 A receiver may be installed between the two).

  By the way, the heat pump 4 may be capable of changing its output. For example, the output of the heat pump 4 can be changed by changing the power supply frequency of the motor of the compressor 13 and hence the rotational speed with an inverter. However, in the following, an example in which the heat pump 4 is operated at a constant output while the power frequency of the motor of the compressor 13 is maintained constant will be described.

  The feed water heating system 1 of the present embodiment further includes a waste heat recovery heat exchanger 12. This waste heat recovery heat exchanger 12 is an indirect heat exchanger between the water in the water supply channel 8 upstream of the subcooler 17 and the heat source water after passing through the evaporator 16. Therefore, the water in the water supply channel 8 is passed through the waste heat recovery heat exchanger 12, the supercooler 17, and the condenser 14 in order. On the other hand, the heat source water in the heat source water tank 5 is passed through the evaporator 16 via the heat source supply path 18 and then passed to the waste heat recovery heat exchanger 12.

  The heat source water tank 5 stores heat source water as a heat source of the heat pump 4. The heat source water is, for example, waste hot water (hot water discharged from a factory or the like). The heat source water tank 5 is provided with a heat source water supply path 19 and an overflow path 20 for overflowing a predetermined amount or more of water.

  The heat source water in the heat source water tank 5 is passed through the heat source supply path 18 to the evaporator 16 of the heat pump 4 and then to the waste heat recovery heat exchanger 12. The heat source supply path 18 is provided with a heat source supply pump 21 on the upstream side of the evaporator 16. By operating the heat source supply pump 21, the heat source water from the heat source water tank 5 is discarded with the evaporator 16. The heat recovery heat exchanger 12 can be passed through in order.

  By passing the heat source water through the waste heat recovery heat exchanger 12 after passing the evaporator 16 first, compared with the case where the heat source water is passed through the evaporator 16 after passing the waste heat recovery heat exchanger 12 first. Further, the evaporation temperature (that is, the evaporation pressure) of the refrigerant in the evaporator 16 can be increased, the pressure ratio of the compressor 13 can be reduced, and energy saving can be achieved.

  The water supply tank 3 is provided with a water level detector 22. The configuration of the water level detector 22 is not particularly limited, but is an electrode type water level detector in the present embodiment. In this case, a plurality of electrode rods 23 to 26 having different lengths are inserted and held in the water supply tank 3 with their lower end portions having different height positions. In this embodiment, in addition to the water supply start electrode rod 23 and the water supply stop electrode rod 24 for controlling the water supply valve 10, the makeup water start electrode rod 25 and the makeup water stop electrode rod 26 for controlling the makeup water valve 11 are provided in the water supply tank 3. Has been inserted. At this time, although details will be described later, in this embodiment, the height position of the lower end portion is decreased in the order of the water supply stop electrode rod 24, the makeup water stop electrode rod 26, the water supply start electrode rod 23, and the makeup water start electrode rod 25. And it is inserted in the water supply tank 3.

  Each electrode rod 23-26 detects the presence or absence of the water level in a lower end part by whether the lower end part is immersed in water. In the following, the water level detected by the water supply start electrode rod 23 is the water supply start water level H1, the water level detected by the water supply stop electrode rod 24 is the water supply stop water level H2, the water level detected by the makeup water start electrode rod 25 is the makeup water start water level H3, The water level detected by the makeup water stop electrode rod 26 is referred to as a makeup water stop water level H4.

  The heat source water tank 5 is provided with a water level detector 27 in order to confirm the presence or absence of the heat source water. The configuration of the water level detector 27 is not particularly limited. In the present embodiment, the water level detector 27 is an electrode type water level detector. In this case, the low water level detection electrode rod 28 is inserted into the heat source water tank 5, and it is monitored whether the water level of the heat source water is lower than the setting.

  In the water supply path 8, a hot water temperature sensor 29 is provided on the outlet side of the condenser 14. The tapping temperature sensor 29 detects the water temperature after passing through the condenser 14. Based on the temperature detected by the hot water temperature sensor 29, the water supply valve 10 is controlled. Here, the opening of the water supply valve 10 is adjusted so as to maintain the temperature detected by the tapping temperature sensor 29 at a set temperature. Thereby, the flow rate of the water supply to the water supply tank 3 through the water supply path 8 is adjusted so that the temperature detected by the tapping temperature sensor 29 is maintained at the set temperature.

  The water supply path 8 is further provided with a flow rate detecting means as desired in order to monitor the water flow rate (the water supply flow rate to the water supply tank 3 via the water supply path 8). The flow rate detecting means is the flow meter 30 in this embodiment, but may be a flow switch or the like depending on circumstances. In the illustrated example, the flow meter 30 is provided downstream from the water supply valve 10 and upstream from the waste heat recovery heat exchanger 12.

  A heat source temperature sensor 31 is provided in the heat source supply path 18 on the inlet side of the evaporator 16. The heat source temperature sensor 31 detects the temperature of the heat source water supplied to the evaporator 16. However, the heat source temperature sensor 31 may be provided in the heat source water tank 5 depending on circumstances. Although details will be described later, in this embodiment, the heat pump 4 (more specifically, the compressor 13) can be started and stopped and the set temperature can be changed based on the temperature detected by the heat source temperature sensor 31.

  Next, control (operation method) of the feed water heating system 1 of the present embodiment will be described. A series of control described below is automatically performed using a controller (not shown).

  Water supply to the water supply tank 3 is performed by controlling the water supply valve 10 and the replenishment water valve 11 based on the detection signal of the water level detector 22 provided in the water supply tank 3. Specifically, the water supply to the water supply tank 3 via the water supply path 8 starts when the water level in the water supply tank 3 falls below the water supply start water level H1, and exceeds the water supply stop water level H2 higher than the water supply start water level H1. And stop. Further, the water supply to the water supply tank 3 via the makeup water channel 9 starts when the water level in the water supply tank 3 falls below the makeup water start water level H3, and exceeds the makeup water stop water level H4 higher than the makeup water start water level H3. And stop. Here, the makeup water start water level H3 is set lower than the feed water start water level H1, and the makeup water stop water level H4 is set higher than the feed water start water level H1 but lower than the feed water stop water level H2.

  Because of such a configuration, if the water supply stop electrode rod 24 detects the water level, the water supply valve 10 is closed and the replenishment water valve 11 is also closed, assuming that the water level in the water supply tank 3 is sufficient. doing. When the water level in the water supply tank 3 drops due to water supply from the water supply tank 3 to the boiler 2 and the water supply start electrode rod 23 no longer detects the water level, the water supply valve 10 is opened. Thus, water is supplied to the water supply tank 3 through the water supply passage 8, but when the water supply stop electrode rod 24 detects the water level, the water supply valve 10 is closed. On the other hand, even if the water supply valve 10 is opened, the water level of the water supply tank 3 cannot be recovered, the water level of the water supply tank 3 is further lowered, and the makeup water start electrode rod 25 no longer detects the water level, the makeup water valve 11 is also opened. To do. Thus, water is supplied to the water supply tank 3 also through the supply water channel 9, but when the water level of the water supply tank 3 recovers and the supply water stop electrode rod 26 detects the water level, the supply water valve 11 is closed, and further When the water level recovers and the water supply stop electrode rod 24 detects the water level, the water supply valve 10 is closed. In addition, the water supply valve 10 is opened, and the water supply to the water supply tank 3 through the water supply passage 8 is also operated.

  In this embodiment, the makeup water stop water level H4 is set higher than the feed water start water level H1 but lower than the feed water stop water level H2. As a result, the water level region between the water supply start water level H1 and the water supply stop water level H2 and the water level region between the makeup water start water level H3 and the makeup water stop water level H4 partially overlap each other. Therefore, it is easy to ensure the water level difference between the water supply start water level H1 and the water supply stop water level H2, and the water level difference between the makeup water start water level H3 and the makeup water stop water level H4. Along with this, the number of times of opening and closing the water supply valve 10 and the makeup water valve 11 can be reduced. Furthermore, since the makeup water stop water level H4 is relatively high, the water supply speed to the water supply tank 3 can be increased, and a relatively large amount of water can be stored in the water supply tank 3. Therefore, there is no fear that the amount of water stored in the water supply tank 3 will be insufficient, and priority can be given to the operation of the most important boiler 2 and its steam using equipment. Moreover, the time until the water supply tank 3 is filled with water from an empty state can be shortened.

  The water level difference between the water supply start water level H1 and the makeup water start water level H3 is preferably set smaller than the water level difference between the water supply start water level H1 and the water supply stop water level H2. By bringing the water supply start water level H1 and the makeup water start water level H3 close to each other, both the water supply through the water supply channel 8 and the water supply through the makeup water channel 9 can be easily performed. Thereby, the water supply speed to the water supply tank 3 can be increased.

  As will be described later, the heat pump 4 operates in a predetermined case. The heat pump 4 is switched between operation and stop depending on whether or not the compressor 13 is activated. During the operation of the heat pump 4, the compressor 13 is maintained at a constant power output frequency and a constant output.

  During the water supply to the water supply tank 3 through the water supply path 8, the opening of the water supply valve 10 is adjusted so as to maintain the detected temperature of the hot water temperature sensor 29 at the set temperature (the hot water temperature constant control by PID control). The set temperature is basically fixed (the set temperature in that case is particularly referred to as the first set temperature), but may be changed according to the situation as will be described later.

  By the way, when the water supply valve 10 is closed and the compressor 13 is stopped, the response speed of the water supply valve 10 is slow when the water supply valve 10 is opened and the compressor 13 is started. The water flow rate of the condenser 14 is insufficient, the refrigerant pressure on the discharge side of the compressor 13 exceeds the upper limit value, and the compressor 13 may be interlocked. That is, when the compressor 13 is started, the compressor 13 rises relatively quickly up to the steady rotational speed. At this time, the opening degree adjustment of the water supply valve 10 is easily delayed due to the increase in the refrigerant pressure on the discharge side, and the condenser 14 A state in which the water flow rate of the refrigerant is not ensured is desired, the refrigerant is not condensed in the condenser 14, and the pressure of the refrigerant excessively increases on the discharge side of the compressor 13, and the compressor 13 may be forcibly stopped. There is. Therefore, the feed water warming system 1 of the present embodiment opens the feed valve 10 and starts the compressor 13 from a state in which the feed valve 10 is closed and the compressor 13 is stopped. ), Any one of the following controls (A) to (C) is executed. Note that “when the water supply valve 10 is opened and the compressor 13 is started” does not necessarily require that the water supply valve 10 is opened and the compressor 13 is started at the same time. The case where the compressor 13 is started after opening is also included.

≪ (A) Lowering the set temperature of the hot water temperature constant control≫
When the water supply valve 10 is closed and the compressor 13 is stopped, when the water supply valve 10 is opened and the compressor 13 is started, the set temperature of the hot water temperature constant control (on the outlet side of the condenser 14) until the set condition is satisfied. Reduce the target water temperature). Specifically, the set temperature of the hot water temperature constant control is basically the first set temperature (for example, 75 ° C.), but is set when the feed valve 10 is opened and the compressor 13 is started. Until the condition (e.g., the elapse of the set time) is satisfied, the starting set temperature is lower than the first set temperature (e.g., 60 [deg.] C.). In the constant hot water temperature control, the lower the set temperature, the higher the feed water flow rate. Therefore, when opening the feed valve 10 and starting the compressor 13, the set temperature is lowered so that the water supply flow rate 8 can be reduced. A water supply flow rate to the water supply tank 3 can be secured, and the discharge-side refrigerant pressure can be prevented from excessively rising when the compressor 13 is started. In other words, the lower the set temperature, the more the operation can be performed while the refrigerant pressure on the discharge side of the compressor 13 is kept relatively low, and the refrigerant pressure on the discharge side of the compressor 13 can be easily prevented from exceeding the upper limit value.

  Moreover, it is preferable that the starting set temperature is raised stepwise to the first set temperature every set time (for example, 60 seconds). For example, the set temperature may be switched between 60 ° C., 65 ° C., 70 ° C., and 75 ° C. every 60 seconds. When switching from the set temperature for starting at the time of starting the compressor 13 to the first set temperature at once, there is a possibility that a sudden decrease in the feed water flow rate to the feed water tank 3 through the feed water channel 8 may occur, but in steps. Such inconvenience can be avoided by switching.

  By the way, the initial value of the starting set temperature (the first set temperature when the set temperature is changed stepwise) is a temperature obtained by adding a predetermined temperature to the water temperature of the water supply source to the water supply path 8. The predetermined temperature is preferably set in a range of 1/2 to 4/5 of the difference between the water temperature of the water supply source (for example, 10 to 30 ° C.) and the first set temperature (for example, 75 ° C.). Considering the fact that if the pressure is too low, the water supply to the water supply tank 3 cannot be sufficiently heated, and if it is too high, the flow rate of the water supply is insufficient and the compressor 13 may be interlocked when the compressor 13 is started. It is.

≪ (B) The opening degree of the water supply valve 10 is set to the set opening degree or more >>
When opening the water supply valve 10 and starting the compressor 13 from the state where the water supply valve 10 is closed and the compressor 13 is stopped, the opening of the water supply valve 10 is set to be equal to or larger than the set opening (preferably fully open). Specifically, when the water supply valve 10 is opened and the compressor 13 is started, the start time of the hot water temperature constant control is delayed, and until then, the opening of the water supply valve 10 is preferably fully opened. By controlling the water supply valve 10 to be fully open, the water supply flow rate to the water supply tank 3 through the water supply passage 8 is secured, and the refrigerant pressure on the discharge side is prevented from excessively rising when the compressor 13 is started. it can.

  After the water supply valve 10 is fully opened for a predetermined time, it is preferable to reduce the opening of the water supply valve 10 over time (typically in proportion to the elapsed time) until the set condition is satisfied. As the opening degree of the water supply valve 10 is reduced, the temperature detected by the hot water temperature sensor 29 increases. However, when the temperature reaches the first set temperature, it is preferable to switch to the constant hot water temperature control (PID control). By gradually reducing the opening of the water supply valve 10 from the fully open position, the supply water flow rate to the water supply tank 3 via the water supply path 8 is suddenly reduced and the refrigerant pressure on the discharge side of the compressor 13 is excessively increased accordingly. Can be prevented from rising. In addition, when making the opening degree of the water supply valve 10 small with time, it is good to make it small continuously, but you may make it small in steps depending on the case.

<< (C) The supply flow rate of the heat source water to the evaporator 16 is set equal to or less than the set flow rate >>
During the constant temperature control of the hot water, the heat source supply pump 21 passes the heat source water at a predetermined flow rate to the evaporator 16, but when the feed valve 10 is opened and the compressor 13 is started, the setting condition is satisfied. The supply of heat source water to the evaporator 16 is made smaller than the predetermined flow rate. Specifically, when the water supply valve 10 is opened and the compressor 13 is started, the heat source supply pump 21 is inverter-controlled or the opening degree of a valve (not shown) provided downstream from the heat source supply pump 21 is reduced. Thus, the supply flow rate of the heat source water to the evaporator 16 may be reduced to about half, for example. By restricting the supply flow rate of the heat source water to the evaporator 16, it is possible to prevent the refrigerant pressure on the discharge side from rising excessively when the compressor 13 is started.

  When the set time elapses, the discharge pressure of the compressor 13 exceeds a predetermined value, or the rotation speed of the compressor 13 reaches a predetermined value, the supply flow rate of the heat source water to the evaporator 16 is gradually increased to a predetermined flow rate. It may be increased (typically in proportion to elapsed time). Thereby, an excessive increase in the refrigerant pressure on the discharge side of the compressor 13 can be prevented. In addition, when increasing the supply flow rate of the heat source water to the evaporator 16 with time, it is preferable to increase it continuously, but it may be increased stepwise if necessary.

  By the way, when the water supply valve 10 is opened and the compressor 13 is started, first, the compressor 13 is started on the condition that the water supply valve 10 is opened and it is detected that water supply of a predetermined flow rate or more is secured. Is preferred. This is because if the supply water flow rate is insufficient when the compressor 13 is activated, the pressure on the discharge side of the compressor 13 increases as described above, and the compressor 13 stops. In order to confirm that water supply of a predetermined flow rate or more is secured by opening the water supply valve 10, it is not possible to cope with changes in the water supply source pressure or the like simply by opening the water supply valve 10 to a constant opening. Therefore, in this embodiment, the control is performed as follows.

  That is, while monitoring the water flow rate with the flow meter 30 provided in the water supply path 8, the opening degree of the water supply valve 10 is gradually increased (typically in proportion to the elapsed time). When the predetermined flow rate is detected, the opening of the water supply valve 10 is fixed in that state, and water supply of a predetermined flow rate or more is ensured depending on whether the state can be continued until a predetermined time (for example, 10 seconds after the water supply valve 10 is opened). It is determined whether or not. At this time, the opening degree of the water supply valve 10 may be adjusted so as to become a predetermined flow rate instead of fixing the opening degree when the flow meter 30 detects the predetermined flow rate. In any case, after determining that water supply of a predetermined flow rate or more is ensured, the compressor 13 can be started and, for example, the constant hot water temperature control is performed via the control (A). .

  Moreover, since the above-mentioned starting control occurs when the temperature of the heat source water to the evaporator 16 is high, it is preferable to switch the execution of the heat source water according to the temperature of the heat source water to the evaporator 16. That is, it is preferable to perform the start control when the temperature detected by the heat source temperature sensor 31 exceeds the switching temperature and not when the temperature is equal to or lower than the switching temperature. Since start-up control is not performed when the heat source water temperature is low, the start-up time of the feed water heating system can be shortened. Note that the switching temperature is lower than the first set temperature, and can be set as a temperature lower than the initial value of the startup set temperature by a predetermined temperature, for example.

  Next, a supplementary explanation will be given of the hot water temperature constant control. As described above, in the feed water warming system 1 of the present embodiment, water supply to the water supply tank 3 through the water supply path 8 is controlled based on the water level in the water supply tank 3. During the water supply to the tank 3, the heat source water temperature to the evaporator 16 is monitored by the heat source temperature sensor 31, and the heat pump 4 is preferably stopped when the temperature becomes a specified temperature or higher. Even in that case, as long as the water supply condition based on the water level in the water supply tank 3 is satisfied, water is supplied to the water supply tank 3 through the water supply path 8.

  More specifically, in the present embodiment, control is performed as follows. That is, if the temperature detected by the heat source temperature sensor 31 is less than a specified temperature (for example, 60 ° C.) during the water supply to the water supply tank 3 via the water supply path 8, The opening of the water supply valve 10 is adjusted so that the detected temperature is maintained at a first set temperature (for example, 75 ° C.), and the water supply flow rate to the water supply tank 3 via the water supply path 8 is adjusted (first control). . Here, the first set temperature is higher than the specified temperature.

  On the other hand, when the detected temperature of the heat source temperature sensor 31 becomes a specified temperature (for example, 60 ° C.) or higher, the control is switched to the second control. In the second control, the heat pump 4 is stopped. Even in this case, as long as the water supply condition based on the water level in the water supply tank 3 is satisfied, water is supplied to the water supply tank 3 through the water supply path 8, but it is preferable to lower the control target temperature of the outlet side water temperature of the condenser 14. . That is, the opening of the water supply valve 10 is adjusted so that the temperature detected by the hot water temperature sensor 29 is maintained at a second set temperature (for example, 60 ° C.) lower than the first set temperature, and water is supplied via the water supply path 8. The water supply flow rate to the tank 3 is adjusted. Here, the second set temperature is the same temperature as the specified temperature, but may be a temperature lower than the specified temperature in some cases.

  Thus, if the heat source water temperature to the evaporator 16 is lower than the specified temperature, the water supply path 8 is maintained so that the outlet side water temperature of the condenser 14 is maintained at the first set temperature while the heat pump 4 is operated. Regardless of the water temperature of the water supply source or the temperature of the heat source water, hot water having a desired temperature can be obtained by adjusting the flow rate of the water supply to the water supply tank 3 via. On the other hand, since the heat pump 4 is stopped when the temperature of the heat source water to the evaporator 16 exceeds the specified temperature, the compressor 13 can be protected. However, even in that case, the waste heat recovery heat exchanger 12 can exchange heat between the water supply and the heat source water to recover the heat from the heat source water. In addition, by switching the control target temperature of the outlet side water temperature of the condenser 14 to the second set temperature lower than the first set temperature, the water supply flow rate to the water supply tank 3 through the water supply path 8 is ensured to some extent. Thus, heat recovery from the heat source water can be effectively achieved.

  Switching from the second control to the first control is performed as follows. That is, while the heat pump 4 is stopped, the feed water flow rate to the feed water tank 3 via the feed water channel 8 is being adjusted so that the temperature detected by the hot water temperature sensor 29 is maintained at the second set temperature (that is, during the second control). ), When the detected temperature of the heat source temperature sensor 31 continues below the specified temperature for a set time (for example, 60 seconds), the process returns to the first control. In other words, the heat pump 4 is restarted and the control may be switched to control for adjusting the feed water flow rate to the feed water tank 3 via the feed water path 8 so that the temperature detected by the hot water temperature sensor 29 is maintained at the first set temperature.

  However, switching from the second control to the first control may be performed as follows. That is, while the heat pump 4 is stopped, the feed water flow rate to the feed water tank 3 via the feed water channel 8 is being adjusted so that the temperature detected by the hot water temperature sensor 29 is maintained at the second set temperature (that is, during the second control). ), When the temperature detected by the heat source temperature sensor 31 is lower than a predetermined temperature (for example, 58 ° C.) lower than the specified temperature, the first control is returned to. In other words, the heat pump 4 is restarted and the control may be switched to control for adjusting the feed water flow rate to the feed water tank 3 via the feed water path 8 so that the temperature detected by the hot water temperature sensor 29 is maintained at the first set temperature.

  In any case, when the temperature of the heat source water to the evaporator 16 is lowered to a predetermined level, the second control in which the heat pump 4 is stopped can be returned to the first control in which the heat pump 4 is operated. In this way, switching between the first control and the second control is performed according to the heat source water temperature to the evaporator 16.

  However, when the temperature detected by the heat source temperature sensor 31 exceeds the upper limit temperature (for example, 65 ° C.) higher than the specified temperature during water supply to the water supply tank 3 through the water supply path 8, the operation of the water supply heating system 1 is stopped. It is good to do. Specifically, the heat pump 4 is stopped, the heat source supply pump 21 is stopped, and the supply of heat source water to the evaporator 16 is also stopped. Furthermore, the water supply valve 10 is preferably fully closed. Thus, when the heat source water temperature to the evaporator 16 rises excessively, the operation of the feed water heating system 1 can be stopped to protect the feed water warming system 1. Here, the upper limit temperature is higher than the specified temperature but lower than the first set temperature.

  In addition, when the water level of the heat source water tank 5 falls during the operation of the heat pump 4 and the low water level detection electrode rod 28 no longer detects the water level, the operation of the heat pump 4 is stopped, and the heat source supply pump 21 is stopped and the evaporator It is preferable to stop the supply of heat source water to 16. This prevents the heat pump 4 from being wasted. Similarly, when the amount of water supplied to the water supply tank 3 via the water supply path 8 is below the setting, the operation of the heat pump 4 is stopped and the heat source supply pump 21 is turned on. It is preferable to stop the supply of the heat source water to the evaporator 16.

  The feed water warming system 1 of the present invention is not limited to the configuration of the above embodiment, and can be changed as appropriate. In particular, when the water supply valve 10 is opened and the compressor 13 is started, the set temperature of the hot water temperature constant control is lowered, the water supply valve 10 is set to the set opening or more, or the heat source water is supplied to the evaporator 16. If the flow rate is equal to or lower than the set flow rate, other configurations and controls can be changed as appropriate.

  For example, in the embodiment, installation of one or both of the supercooler 17 and the waste heat recovery heat exchanger 12 may be omitted. Moreover, the supplementary water channel 9 provided with the supplementary water valve 11 can be omitted depending on the case. Furthermore, a water supply pump may be provided in the common pipe upstream of the water supply channel 8 and the makeup water channel 9, and a deoxygenation device or the like may be provided instead of or in addition to the water softening device 7. Also good.

  In the embodiment, the makeup water stop water level H4 may be set lower than the water supply start water level H1. That is, in the embodiment, the water level is lowered in the order of the water supply stop water level H2, the makeup water stop water level H4, the water supply start water level H1, and the makeup water start water level H3. The water level may be lowered in the order of H1, makeup water stop water level H4, makeup water start water level H3.

  Moreover, although the said Example demonstrated the system which can heat the water supply to the feed water tank 3 of the boiler 2 with the heat pump 4, the utilization place of the stored water of the feed water tank 3 is not restricted to the boiler 2, and can be changed suitably. is there.

  Moreover, although the said Example demonstrated the example which used heat-source water as a heat source of a heat pump, various fluids, such as not only heat-source water but air and waste gas, can be used as a heat-source fluid of a heat pump.

  Moreover, in the said Example, when operating the heat pump, the power supply frequency of the motor of the compressor was maintained constant, but you may control so that the discharge pressure of a compressor may be maintained predetermined depending on the case. Alternatively, the output of the compressor may be adjusted based on the water level in the water supply tank or the heat source fluid temperature to the evaporator.

  Further, the heat pump 4 is not limited to a single stage, and may be a plurality of stages. When the heat pump 4 has a plurality of stages, adjacent stage heat pumps may be connected using an indirect heat exchanger, or may be connected using a direct heat exchanger (intercooler). In the latter case, an intermediate cooler that receives the refrigerant from the compressor of the low stage heat pump and the refrigerant from the expansion valve of the high stage heat pump and exchanges heat by directly contacting both refrigerants is provided. It is a low-stage heat pump condenser and a high-stage heat pump evaporator. As described above, the multi-stage (multi-stage) heat pump includes a single-stage multi-stage heat pump, a multi-element (multi-element) heat pump, or a combination thereof.

  Furthermore, in the said Example, although the compressor 13 of the heat pump 4 was driven by the electric motor, the drive source of the compressor 13 is not ask | required in particular. For example, the compressor 13 may be driven by a steam motor (steam engine) that generates power using steam instead of or in addition to the electric motor, or may be driven by a gas engine.

DESCRIPTION OF SYMBOLS 1 Supply water warming system 2 Boiler 3 Supply water tank 4 Heat pump 5 Heat source water tank 7 Soft water device 8 Supply water path 9 Supply water path 10 Supply water valve 11 Supply water valve 12 Waste heat recovery heat exchanger 13 Compressor 14 Condenser 15 Expansion valve 16 Evaporation 18 Heat source supply path 21 Heat source supply pump 22 Water level detector 29 Hot water temperature sensor 30 Flow meter (flow rate detection means)
31 Heat source temperature sensor

Claims (10)

A compressor, a condenser, an expansion valve, and an evaporator are sequentially connected in an annular manner to circulate the refrigerant, draw up heat from a heat source fluid that passes through the evaporator, and heat water that passes through the condenser When,
A water supply tank capable of supplying water by a water supply channel via the condenser;
A water supply valve that is provided in the water supply channel and adjusts a water supply flow rate to the water supply tank via the water supply channel;
During the water supply to the water supply tank via the water supply path, the opening of the water supply valve is adjusted to maintain the outlet side water temperature of the condenser at a set temperature,
From the state where the water supply valve is closed and the compressor is stopped, when the water supply valve is opened and the compressor is started, the set temperature is lowered or the water supply valve is set to a set opening or more, Supply of the heat source fluid to the evaporator is a set flow rate or less. While the water supply to the water supply tank through the water supply path, the opening of the water supply valve is adjusted to maintain the outlet side water temperature of the condenser at a first set temperature,
When opening the water supply valve and starting the compressor, a starting set temperature lower than the first set temperature is set as the set temperature until a set condition is satisfied. Item 2. A water heating system according to Item 1. 3. The feed water addition according to claim 2, wherein when starting the compressor while opening the feed valve, the set temperature for starting is gradually raised to the first set temperature for each set time. Temperature system. The initial value of the starting set temperature is a temperature obtained by adding a predetermined temperature to the water temperature of the water supply source to the water supply channel,
The feed water warming system according to claim 3, wherein the predetermined temperature is set in a range of 1/2 to 4/5 of a difference between a water temperature of the feed water source and the first set temperature. The feed water heating system according to claim 1, wherein when the compressor is started while opening the feed valve, the feed valve is fully opened. While the water supply to the water supply tank through the water supply path, the opening of the water supply valve is adjusted to maintain the outlet side water temperature of the condenser at a first set temperature,
When opening the water supply valve and starting the compressor, the water supply valve is fully opened, and thereafter, the opening of the water supply valve is decreased over time until a set condition is satisfied. Item 6. A water heating system according to Item 5. While supplying water to the water supply tank via the water supply channel, the opening of the water supply valve is maintained so that the outlet water temperature of the condenser is maintained at a first set temperature while passing a heat source fluid through the evaporator at a predetermined flow rate. Adjust the
When opening the water supply valve and starting the compressor, the supply of the heat source fluid to the evaporator is made smaller than the predetermined flow rate until a set condition is satisfied, and then the time until the predetermined flow rate is reached. The feed water warming system according to claim 1, wherein When opening the feed valve and starting the compressor, the control temperature is lowered, the feed valve is set to a set opening or more, or the supply of the heat source fluid to the evaporator is set to a set flow rate or less. The heating is performed when the temperature of the heat source fluid to the evaporator exceeds the switching temperature, and is not performed when the temperature is lower than the switching temperature. The feed water heating according to any one of claims 1 to 7, system. When opening the water supply valve and starting the compressor, first, the compressor is started on the condition that the water supply valve is opened and it is detected that water supply of a predetermined flow rate or more is secured.
The detection is detection of whether the state can be continued until a predetermined time by opening the water supply valve until a flow rate detecting means provided in the water supply path detects the predetermined flow rate. The feed water warming system according to any one of 8. A waste heat recovery heat exchanger that exchanges heat between water in the water supply channel upstream of the condenser and the heat source fluid after passing through the evaporator;
The presence or absence of water supply to the water supply tank via the water supply channel is switched based on the water level of the water supply tank,
If the heat source fluid temperature to the evaporator is lower than a specified temperature during water supply to the water supply tank via the water supply channel, the outlet side water temperature of the condenser is first set while the heat pump is operated. Adjust the opening of the water supply valve to maintain the temperature,
When the heat source fluid temperature to the evaporator is equal to or higher than a specified temperature during water supply to the water supply tank via the water supply path, the outlet side water temperature of the condenser is set to the first setting while the heat pump is stopped. The feed water heating system according to any one of claims 1 to 9, wherein the opening degree of the feed water valve is adjusted so as to maintain a second set temperature lower than the temperature.

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