JP7303553B2 - hot water system - Google Patents

Description

TECHNICAL FIELD The present invention relates to a hot water supply system provided with a heat exchanger that generates hot water by heat exchange between a heating fluid and water.

2. Description of the Related Art Conventionally, there is known a water heater, which is a type of heating system that generates hot water or hot water by heating cold water or hot water with a heating fluid such as steam (for example, Patent Document 1). The generated hot or hot water is supplied to the user. As one type of such hot water supply apparatus, there is a circulating hot water supply system. In a circulating hot water system, by providing a return pipe to the tank in the pipe from the heat exchanger, hot or hot water is circulated to keep the water temperature constant even when it is not being used. there is Therefore, even at a place away from the water heater, the user can use warm water or hot water with almost no waiting time.

Japanese Patent No. 5103495

In such a hot water supply system, if the heat exchanger fails, hot water cannot be generated, that is, hot water or hot water cannot be supplied to the user, which greatly affects production facilities and the like.

SUMMARY OF THE INVENTION An object of the present invention is to provide a hot water supply system capable of determining deterioration of a heat exchanger and determining replacement time.

To achieve the above object, the hot water supply system of the present invention comprises: a heat exchanger that generates hot water by heat exchange between a heating fluid and water; and a heating fluid supply that supplies the heating fluid to the heat exchanger. theoretical heat exchange amount calculation means for calculating the theoretical heat exchange amount from the value of a sensor that detects pressure or temperature provided in the passage and the opening degree of the heating fluid control valve; heat exchange amount calculation means for calculating an actual heat exchange amount from the temperature and the temperature of the hot water derived from the heat exchanger; and determining deterioration of the heat exchanger from the theoretical heat exchange amount and the heat exchange amount. and determination means for determining. The sensor is, for example, a pressure sensor that measures the pressure of the heating fluid in the heating fluid supply passage. Also, the heating fluid is, for example, steam.

According to this configuration, the theoretical heat exchange amount calculation means calculates the theoretical heat exchange amount from the value of the pressure or temperature sensor provided in the heating fluid supply passage and the opening degree of the heating fluid control valve. Further, the heat exchange amount calculation means calculates the actual heat exchange amount from the flow rate and temperature of the water supplied to the heat exchanger and the temperature of the hot water led out from the heat exchanger. The determination means determines deterioration of the heat exchanger from these theoretical heat exchange amount and heat exchange amount. In other words, the determining means compares the theoretical amount of heat exchange in which the heat exchanger is not deteriorated with the actual amount of heat exchange at present, and determines the deterioration of the heat exchanger from the difference. This makes it possible to determine when to replace the heat exchanger, and to replace the heat exchanger before it fails. As a result, it is possible to avoid being unable to supply hot water or hot water to the user, and to prevent adverse effects on production facilities and the like.

In the present invention, the theoretical condensate temperature at the outlet of the heat exchanger is calculated from the value of the sensor, the degree of opening of the heating fluid control valve, and the flow rate and temperature of water supplied to the heat exchanger. A water temperature calculation means and a correction means for correcting the determination of deterioration of the heat exchanger from the theoretical condensate temperature and the outlet condensate temperature of the heat exchanger may be provided.

According to this configuration, the theoretical condensate temperature calculation means calculates the heat exchanger from the value of the sensor provided in the heating fluid supply passage, the opening degree of the heating fluid control valve, the flow rate and temperature of the water supplied to the heat exchanger. Calculate the theoretical condensate temperature at the outlet of The correcting means corrects the determination of deterioration of the heat exchanger from this theoretical condensate temperature and the condensate temperature at the outlet of the heat exchanger. That is, the correcting means compares the theoretical condensate temperature at which the heat exchanger is not deteriorated and the actual condensate temperature at present, determines the deterioration of the heat exchanger from the difference, and the determination means Correct the deterioration determination of the heat exchanger. As a result, the accuracy of determination of deterioration of the heat exchanger is improved, and the time to replace the heat exchanger can be determined more accurately.

According to the hot water supply system of the present invention, it is possible to determine when to replace the heat exchanger, and to replace the heat exchanger before it fails.

1 is a schematic configuration diagram showing a hot water supply system according to a first embodiment of the present invention; FIG.

Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a hot water supply system 1 according to a first embodiment of the present invention. The hot water supply system 1 of the present embodiment is a circulation type hot water supply system, but is not limited to the circulation type. The hot water supply system 1 includes a tank 2 that stores water W1, and a heat exchanger 4 that generates hot water W2 by heat exchange between a heating fluid F1 and the water W1 drawn out from the tank 2. Hot water W2 from vessel 4 is returned to tank 2 via the user.

The hot water W2 supplied to the user is set at 98° C., for example. Such hot water W2 is used, for example, for operations such as sterilization and sterilization in production facilities of food manufacturers. Moreover, in this embodiment, steam is used as the heating fluid F1. However, the heating fluid F1 is not limited to steam, and may be high-temperature, high-pressure water, for example.

A water supply passage 6 for supplying water W<b>1 to the heat exchanger 4 is connected to the tank 2 . A pump 8 and a first temperature sensor 10 are provided in the water supply passage 6 . A pump 8 pumps the water W1 in the tank 2 . The first temperature sensor 10 detects the temperature of the water W<b>1 in the water supply passage 6 (water temperature), that is, the water temperature in the tank 2 . In this embodiment, the first temperature sensor 10 is arranged downstream of the pump 8 and upstream of the heat exchanger 4 . The water supply passage 6 is also provided with a strainer 12 for removing foreign substances in the water W1 supplied to the pump 8 and a flow meter 14 for detecting the flow rate of the water W1.

A downstream end of the water supply passage 6 is connected to the water inlet 4 a of the heat exchanger 4 . On the other hand, the upstream end of the hot water supply passage 16 is connected to the water outlet 4 b of the heat exchanger 4 . The water W1 flowing into the heat exchanger 4 from the water inlet 4a undergoes heat exchange with the heating fluid F1 in the heat exchanger 4 to become hot water W2. The generated hot water W2 is led out to the hot water supply passage 16 from the water outlet 4b. The configuration of the heat exchanger 4 on the heating fluid F1 side will be described later.

The hot water supply passage 16 is provided with a second temperature sensor 18, a first pressure sensor 19, and a check valve 17 on the upstream side thereof. A second temperature sensor 18 detects the temperature of the hot water W2 in the hot water supply passage 16 . The inlet of the user side pipe 100 is connected to the downstream end of the hot water supply passage 16 .

A hot water return passage 22 is connected to the outlet of the user side pipe 100 . The hot water W2 supplied to the user side pipe 100 is returned to the tank 2 through the hot water return passage 22. As shown in FIG. A solenoid valve 24 is provided in the hot water return passage 22 . The solenoid valve 24 is closed, for example, when stopping the supply of the hot water W2 from the user-side pipe 100 to the tank 2 in the hot water supply system.

A water supply passage 26 is connected to the tank 2 . A ball tap 28 is provided at the downstream end of the water supply passage 26 . In other words, the water supply passage 26 supplies the cold water W3 to the tank 2 when the water level in the tank 2 falls below the set level to keep the water level at the set level. The cold water W3 is tap water, for example, and is supplied to the water supply passage 26 from the water supply port 26a that is the inlet of the water supply passage 26. As shown in FIG.

The configuration of the heating fluid (steam) F1 side in the heat exchanger 4 will be described. The hot water supply system 1 has a heating fluid supply passage 34 that supplies a heating fluid F<b>1 to the heat exchanger 4 . A heating fluid control valve 36 and a second pressure sensor 38 are provided in the heating fluid supply passage 34 . A heating fluid control valve 36 regulates the amount of heating fluid F1 supplied to the heat exchanger 4 . The heating fluid control valve 36 of this embodiment is an electric ball valve. However, the heating fluid control valve 36 is not limited to this. A second pressure sensor 38 detects the pressure of the heating fluid F<b>1 within the heating fluid supply passage 34 . The heating fluid supply passage 34 is also provided with a strainer 40 for removing foreign matter from the heating fluid F1 introduced into the heating fluid control valve 36 .

A downstream end of the heating fluid supply passage 34 is connected to the heating fluid inlet 4 c of the heat exchanger 4 . On the other hand, the upstream end of the heating fluid discharge passage 42 is connected to the heating fluid outlet 4 d of the heat exchanger 4 . The heating fluid F1 that has flowed into the heat exchanger 4 from the heating fluid inlet 4c exchanges heat with the water W1 in the heat exchanger 4 to heat the water W1. is derived to

A third temperature sensor 44 is provided in the heating fluid discharge passage 42 . A third temperature sensor 44 detects the temperature of the heating fluid F<b>1 in the heating fluid discharge passage 42 . A steam trap 46 is provided at the downstream end of the heating fluid discharge passage 42 . Condensate (drain) F2 in the heating fluid discharge passage 42 is discharged from the drain passage 48 by the steam trap 46 .

A drain extraction passage 50 is connected to the upstream side of the heating fluid control valve 36 in the heating fluid supply passage 34 . A steam trap 52 is also provided at the downstream end of the drain extraction passage 50 .

Each device of hot water supply system 1 is controlled by control device 55 . Specifically, the output values of the first to third temperature sensors 10, 18, 44, the first and second pressure sensors 19, 38, the flow meter 14, etc. , the heating fluid control valve 36 and the like operate according to commands from the control device 55 . The control device 55 may be an electric circuit including a relay or the like, or may be an arithmetic device in which a program is implemented.

The control device 55 has theoretical heat exchange amount calculation means 60 , heat exchange amount calculation means 62 , and determination means 64 . The theoretical heat exchange amount calculation means 60 calculates the theoretical heat exchange amount E1 from the value of the second pressure sensor 38 provided in the heating fluid supply passage 34 and the opening degree of the heating fluid control valve 36 . Since the pipe diameter of the heating fluid supply passage 34 is known, if the pressure P1 of the heating fluid F1 and the opening degree V1 of the heating fluid control valve 36 are known, the flow rate Q1 of the heating fluid F1 introduced into the heat exchanger 4 can be calculated. can. From this flow rate Q1, the theoretical heat exchange amount E1 when the heat exchanger 4 is normal, that is, the ideal value of the heat exchange amount can be calculated, for example, by the following equation (1).
E1=a·V1×(b·P1+c) (1)
where a, b, and c are coefficients.

In this embodiment, the value of the pressure sensor is used to calculate the theoretical heat exchange amount E1. good too.

The heat exchange amount calculation means 62 calculates the actual heat exchange amount E2 from the flow rate Q2 and temperature t1 of the water W1 supplied to the heat exchanger 4 and the temperature t2 of the hot water W2 drawn from the heat exchanger 4, for example , is calculated by the following formula (2).
E2=Cp×ρ×Q2×(t2−t1) (2)
where Cp is the heat capacity of the heating fluid and ρ is the density of the heating fluid.

The flow rate Q2 of the water W1 uses the value detected by the flow meter 14, the temperature t1 of the water W1 uses the value detected by the first thermometer 10, and the temperature t2 of the hot water W2 uses the value detected by the second thermometer 19. used. The actual amount of heat exchange E2 can be calculated from the flow rate Q2 of the water W1 and the hot water temperatures t1 and t2 before and after passing through the heat exchanger 4 .

The determination means 64 determines the deterioration of the heat exchanger 4 from the above theoretical heat exchange amount E1 and heat exchange amount E2. That is, the determination means 64 compares the theoretical heat exchange amount E1 in which the heat exchanger 4 is not deteriorated and the current actual heat exchange amount E2, and determines the deterioration state of the heat exchanger 4 from the difference. judge. For example, when the difference (E1-E2) between the theoretical heat exchange amount E1 and the actual heat exchange amount E2 is greater than 15% of the theoretical heat exchange amount E1 ((E1-E2)/E1>0 .15), the determination means 64 determines that the heat exchanger 4 has deteriorated. However, the numerical value for deterioration determination is not limited to this. When it is determined that the heat exchanger 4 is in a deteriorated state, for example, a lamp display, voice guidance, or the like is used to notify the user.

The control device 55 further has theoretical condensate temperature calculation means 66 and correction means 68 . The theoretical condensate temperature calculation means 66 calculates the value of the second pressure sensor 38 provided in the heating fluid supply passage 34, the opening degree of the heating fluid control valve 36, the flow rate of the water W1 supplied to the heat exchanger 4 (flow meter 14) and the temperature (detected value of the first thermometer 10), the theoretical condensate temperature T1 at the outlet 4d of the heat exchanger 4 is calculated.

As described above, if the pressure of the heating fluid F1 and the degree of opening of the heating fluid control valve 36 are known, the flow rate of the heating fluid F1 introduced into the heat exchanger 4 can be calculated. When the heat exchanger 4 in a normal state (not deteriorated) heat-exchanges the heating fluid F1 at this flow rate and the water W1 at the flow rate and temperature supplied to the heat exchanger 4, after the heat exchange (heat The theoretical condensate temperature T1 of the heated fluid F1 at the outlet 4d) of the exchanger 4 when the heat exchanger 4 is normal, that is, the ideal value of the condensate temperature can be calculated.

The correction means 68 judges deterioration of the heat exchanger 4 from the theoretical condensate temperature T1 and the actual condensate temperature T2 at the outlet 4d of the heat exchanger 4, and corrects the judgment result by the judgment means 64. FIG. That is, the correcting means 68 compares the theoretical condensate temperature T1 in which the heat exchanger 4 is not deteriorated and the current actual condensate temperature T2, and determines the deterioration state of the heat exchanger 4 from the difference. judge. As the actual condensate temperature T2 at the outlet 4d of the heat exchanger 4, the value detected by the third thermometer 44 is used. The correction means 68 judges the degree of deterioration of the heat exchanger 4 from the difference (T1-T2) between the theoretical condensate temperature T1 and the actual condensate temperature T2, and corrects the judgment result by the judgment means 64. FIG. For example, even if the determination means 64 determines that the deterioration has not occurred, if the value calculated by the correction means 68 is larger than a predetermined value, it may be determined that the determination means 64 has deteriorated.

According to the above configuration, the theoretical heat exchange amount calculation means 60 calculates the theoretical heat exchange amount E1 from the value of the second pressure sensor 38 and the opening degree of the heating fluid control valve 36 . Further, the heat exchange amount calculation means 62 calculates the actual heat exchange amount E2 from the flow rate and temperature of the water W1 supplied to the heat exchanger 4 and the temperature of the hot water W2 drawn out from the heat exchanger 4. The determination means 64 determines deterioration of the heat exchanger 4 from these theoretical heat exchange amount E1 and heat exchange amount E2. It is possible to determine when to replace the heat exchanger 4 and to replace the heat exchanger 4 before the heat exchanger 4 fails. As a result, it is possible to prevent the hot water W2 from becoming impossible to supply to the user, thereby preventing adverse effects on production facilities and the like.

Further, the theoretical condensate temperature calculation means 66, the value of the second pressure sensor 38, the opening degree of the heating fluid control valve 36, the flow rate and temperature of the water W1 supplied to the heat exchanger 4, the outlet 4d of the heat exchanger 4 Calculate the theoretical condensate temperature T1. The correcting means 68 corrects the determination of the deterioration of the heat exchanger 4 from the theoretical condensate temperature T1 and the actual condensate temperature T2 at the outlet 4d of the heat exchanger 4 (the value detected by the third thermometer 44). That is, the correction means 66 compares the theoretical condensate temperature t1 at which the heat exchanger 4 is not deteriorated and the current actual condensate temperature T2, and determines the deterioration of the heat exchanger 4 from the difference. Then, the deterioration determination of the heat exchanger 4 by the determining means 64 is corrected as necessary. As a result, the accuracy of determination of deterioration of the heat exchanger 5 is improved, and the replacement timing of the heat exchanger 4 can be determined more accurately.

By using steam as the heating fluid F1, the heat exchanger 4 can quickly raise the temperature of the water.

The present invention is not limited to the above embodiments, and various additions, changes, or deletions are possible without departing from the scope of the present invention. For example, in the above embodiments, a circulating hot water supply system has been described, but the present invention can also be applied to a hot water supply system other than a circulating hot water supply system. Moreover, although the hot water supply system of the above embodiment includes the tank 2 for storing the water W1, the tank 2 may be omitted. Accordingly, such are also included within the scope of this invention.

1 hot water supply system 4 heat exchanger 34 heating fluid supply passage 36 heating fluid control valve 38 second pressure sensor (sensor)
60 theoretical heat exchange amount calculation means 62 heat exchange amount calculation means 64 determination means 66 theoretical condensate temperature calculation means 68 correction means F1 heating fluid (steam)
W1 Water W2 Hot water

Claims (3)

a heat exchanger for generating hot water by exchanging heat between a heating fluid and water;
a heating fluid supply passage for supplying the heating fluid to the heat exchanger ;
a water supply passage for supplying the water to the heat exchanger;
a hot water supply passage through which the hot water generated by the heat exchanger is led;
a heating fluid discharge passage through which the heating fluid after heat exchange with the water in the heat exchanger is discharged;
a sensor for detecting the pressure or temperature of the heating fluid flowing through the heating fluid supply passage ;
a heating fluid control valve that adjusts the flow rate of the heating fluid flowing through the heating fluid supply passage ;
theoretical heat exchange amount calculation means for calculating a theoretical heat exchange amount from the value of the sensor and the degree of opening of the heating fluid control valve;
heat exchange amount calculation means for calculating an actual heat exchange amount from the flow rate and temperature of the water flowing through the water supply passage and the temperature of the hot water flowing through the hot water supply passage ;
Determination means for determining deterioration of the heat exchanger from the theoretical heat exchange amount and the heat exchange amount;
theoretical condensate temperature calculation for calculating the theoretical condensate temperature of the heating fluid flowing through the heating fluid discharge passage from the value of the sensor, the degree of opening of the heating fluid control valve, and the flow rate and temperature of the water flowing through the water supply passage means and
a correction means for correcting determination of deterioration of the heat exchanger from the theoretical condensate temperature and the condensate temperature of the heating fluid actually flowing through the heating fluid discharge passage. 2. The hot water supply system according to claim 1 , wherein said sensor is a pressure sensor that measures the pressure of said heating fluid in said heating fluid supply passage. 3. The hot water system according to claim 1 or 2 , wherein said heating fluid is steam.

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