JP2022032507A - Hot water supply system - Google Patents

Abstract

To provide a hot water supply system for determining the deterioration of a heat exchanger to discriminate a replacement timing.SOLUTION: A hot water supply system 1 includes a heat exchanger 4 for generating heated water with heat exchange between heating fluid F1 and water W1. A pressure sensor 38 is provided in a heating fluid supply passage 34 which supplies the heating fluid F1 to the heat exchanger 4. Theoretical heat exchange amount calculation means 60 calculates a theoretical heat exchange amount E1 from a value detected by the pressure sensor 38 and the opening of a heating fluid adjusting valve 36. Heat exchange amount calculation means 62 calculates an actual heat exchange amount E2 from the flow rate and the temperature of the water W1 supplied to the heat exchanger 4 and the temperature of the heated water W2 derived from the heat exchanger 4. Determination means 64 determines the deterioration of the heat exchanger 4 from the theoretical heat exchange amount E1 and the heat exchange amount E2.SELECTED DRAWING: Figure 1

Description

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

Conventionally, a hot water supply device which is a kind of a heating system for generating hot water or hot water by heating cold water or hot water with a heating fluid such as steam is known (for example, Patent Document 1). The generated hot or hot water is supplied to the user. As a kind of such a hot water supply device, there is a circulation type hot water supply system. In the circulation type hot water supply system, by providing a return pipe to the tank in the pipe from the heat exchanger, hot water or hot water is circulated and the water temperature is kept constant even when hot water or hot water is not used. There is. Therefore, the user can use hot water or hot water with almost no waiting time even at a place away from the hot water supply device.

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 has a great influence on the production equipment and the like.

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

In order 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 the heating fluid and water, and a heating fluid supply that supplies the heating fluid to the heat exchanger. The theoretical heat exchange amount calculating means for calculating the theoretical heat exchange amount from the value of the sensor for detecting the pressure or temperature provided in the passage and the opening degree of the heating fluid control valve, the flow rate of water supplied to the heat exchanger, and the flow rate of water supplied to the heat exchanger. A heat exchange amount calculating means for calculating the actual heat exchange amount from the temperature and the temperature of the hot water derived from the heat exchanger, and determining the deterioration of the heat exchanger from the theoretical heat exchange amount and the heat exchange amount. It is equipped with a determination means for performing. The sensor is, for example, a pressure sensor that measures the pressure of the heating fluid in the heating fluid supply passage. Further, 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 sensor for detecting the pressure or temperature provided in the heating fluid supply passage and the opening degree of the heating fluid control valve. Further, the heat exchange amount calculating 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 derived from the heat exchanger. From these theoretical heat exchange amounts and heat exchange amounts, the determination means determines the deterioration of the heat exchanger. That is, the determination means compares the theoretical heat exchange amount in which the heat exchanger has not deteriorated with the actual heat exchange amount at present, and determines the deterioration of the heat exchanger from the difference. As a result, it is possible to determine when to replace the heat exchanger, and it is possible to replace the heat exchanger before the heat exchanger fails. As a result, it is possible to prevent the user from being unable to supply hot water or hot water, and to prevent adverse effects on the production equipment and the like.

In the present invention, further, theoretical restoration for calculating the theoretical condensate temperature at the outlet of the heat exchanger from the value of the sensor, the opening degree of the heating fluid control valve, the flow rate and temperature of the 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 condensate temperature at the outlet of the heat exchanger may be provided.

According to this configuration, the theoretical condensate temperature calculation means is a heat exchanger based on 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 correction means corrects the determination of deterioration of the heat exchanger from the theoretical condensate temperature and the condensate temperature at the outlet of the heat exchanger. That is, the correction means compares the theoretical condensate temperature at which the heat exchanger has not deteriorated with the actual condensate temperature at present, determines the deterioration of the heat exchanger from the difference, and uses the determination means. Correct the deterioration judgment of the heat exchanger. As a result, the accuracy of determining the deterioration of the heat exchanger is improved, and the replacement time of 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 it is possible to replace the heat exchanger before the heat exchanger fails.

It is a schematic block diagram which shows the hot water supply system which concerns on 1st Embodiment of this invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a hot water supply system 1 according to the 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 in which water W1 is stored and a heat exchanger 4 that generates hot water W2 by heat exchange between the heating fluid F1 and the water W1 derived from the tank 2 to exchange heat. The hot water W2 from the vessel 4 is returned to the tank 2 via the user.

The hot water W2 supplied to the user is set to, for example, 98 ° C. Such hot water W2 is used, for example, for work such as sterilization and sterilization in the production equipment of a food manufacturer. Further, in the present embodiment, steam is used as the heating fluid F1. However, the heating fluid F1 is not limited to steam, and may be, for example, high-temperature and high-pressure water.

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

The downstream end of the water supply passage 6 is connected to the water inlet 4a 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 4b of the heat exchanger 4. The water W1 that has flowed into the heat exchanger 4 from the water inlet 4a is heat-exchanged 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 heating fluid F1 side in the heat exchanger 4 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. The 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 via the hot water return passage 22. A solenoid valve 24 is provided in the hot water return passage 22. The solenoid valve 24 is closed, for example, when the supply of hot water W2 from the user-side piping 100 to the tank 2 in the hot water supply system is stopped.

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. That is, the water supply passage 26 replenishes the tank 2 with cold water W3 when the water level in the tank 2 drops below the set level, and keeps the water level at the set level. The cold water W3 is, for example, tap water and is supplied to the water supply passage 26 from the water supply port 26a which is the entrance of the water supply passage 26.

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 for supplying the heating fluid F1 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. The heating fluid control valve 36 regulates the supply amount of the heating fluid F1 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. The second pressure sensor 38 detects the pressure of the heating fluid F1 in the heating fluid supply passage 34. The heating fluid supply passage 34 is also provided with a strainer 40 for removing foreign matter in the heating fluid F1 introduced into the heating fluid control valve 36.

The downstream end of the heated fluid supply passage 34 is connected to the heated fluid inlet 4c of the heat exchanger 4. On the other hand, the upstream end of the heated fluid discharge passage 42 is connected to the heated fluid outlet 4d of the heat exchanger 4. The heated fluid F1 flowing into the heat exchanger 4 from the heated fluid inlet 4c exchanges heat with the water W1 in the heat exchanger 4 to heat the water W1, and then the heated fluid discharge passage 42 from the heated fluid outlet 4d. Is derived to.

A third temperature sensor 44 is provided in the heated fluid discharge passage 42. The third temperature sensor 44 detects the temperature of the heating fluid F1 in the heating fluid discharge passage 42. A steam trap 46 is provided at the downstream end of the heated fluid discharge passage 42. The steam trap 46 discharges the condensate (drain) F2 in the heated fluid discharge passage 42 from the drain passage 48.

A drain take-out 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 take-out passage 50.

Each device of the hot water supply system 1 is controlled by the 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. are input to the control device 55, and the pump 8 and the solenoid valve 24 are input. , The equipment such as the heating fluid control valve 36 operates according to the command of the control device 55. The control device 55 may be an electric circuit including a relay or the like, or may be an arithmetic unit on which a program is mounted.

The control device 55 has a theoretical heat exchange amount calculation means 60, a heat exchange amount calculation means 62, and a determination means 64. The theoretical heat exchange amount calculating 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 is 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 by, for example, the following equation (1).
E1 = a ・ V1 × (b ・ P1 + c) ・ ・ ・ (1)
Here, a, b, and c are coefficients.

In the present embodiment, the value of the pressure sensor is used for calculating the theoretical heat exchange amount E1, but instead of this, a temperature sensor for detecting the temperature of the heated fluid supply passage 34 is provided, and the value is used. May be good.

The heat exchange amount calculating means 62 obtains, for example, an 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 derived from the heat exchanger 4. , Calculated by the following formula (2).
E2 = Cp × ρ × Q2 × (t2-t1) ... (2)
Here, Cp is the heat capacity of the heating fluid, and ρ is the density of the heating fluid.

The detection value of the flow meter 14 is used for the flow rate Q2 of the water W1, the detection value of the first thermometer 10 is used for the temperature t1 of the water W1, and the detection value of the second thermometer 19 is used for the temperature t2 of the hot water W2. It is used. The actual heat exchange amount E2 can be calculated from the flow rate Q2 of the water W1 and the hot water temperatures t1 and t2 before and after the passage of the heat exchanger 4.

The determination means 64 determines the deterioration of the heat exchanger 4 from the above-mentioned 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 has not deteriorated with the actual heat exchange amount E2 at present, and determines the deterioration status 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 larger than 15% of the theoretical heat exchange amount E1 ((E1-E2) / E1> 0). In .15), the determination means 64 determines that the heat exchanger 4 has deteriorated. However, the numerical value of the deterioration determination is not limited to this. When it is determined that the heat exchanger 4 is in a deteriorated state, it is notified by, for example, a lamp display, voice guidance, or the like.

The control device 55 further includes a theoretical condensate temperature calculation means 66 and a correction means 68. The theoretical condensate temperature calculation means 66 includes 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, and the flow rate of the water W1 supplied to the heat exchanger 4 (flow meter). The theoretical condensate temperature T1 at the outlet 4d of the heat exchanger 4 is calculated from the detected value of 14) and the temperature (detected value of the first thermometer 10).

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

The correction means 68 determines the deterioration of the heat exchanger 4 from the theoretical condensate temperature T1 and the condensate temperature T2 at the outlet 4d of the actual heat exchanger 4, and corrects the determination result by the determination means 64. That is, the correction means 68 compares the theoretical condensate temperature T1 in which the heat exchanger 4 has not deteriorated with the actual condensate temperature T2 at present, and determines the deterioration status of the heat exchanger 4 from the difference. judge. As the condensate temperature T2 at the outlet 4d of the actual heat exchanger 4, the detected value of the third thermometer 44 is used. The correction means 68 determines 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 determination result by the determination means 64. For example, even when it is determined that the determination means 64 has not deteriorated, if the value calculated by the correction means 68 is larger than the predetermined value, it may be determined that the determination means 64 has deteriorated.

According to the above configuration, the theoretical heat exchange amount calculating 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 calculating 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 derived from the heat exchanger 4. From these theoretical heat exchange amounts E1 and heat exchange amount E2, the determination means 64 determines the deterioration of the heat exchanger 4. The replacement time of the heat exchanger 4 can be determined, and the heat exchanger 4 can be replaced before the heat exchanger 4 fails. As a result, it is possible to prevent the hot water W2 from being unable to be supplied to the user, and it is possible to prevent adverse effects on the production equipment and the like.

Further, the theoretical condensate temperature calculation means is 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, and the outlet 4d of the heat exchanger 4. The theoretical condensate temperature T1 is calculated. The correction means 68 corrects the determination of deterioration of the heat exchanger 4 from the theoretical condensate temperature T1 and the actual condensate temperature T2 (detected value of the third thermometer 44) at the outlet 4d of the heat exchanger 4. That is, the correction means 66 compares the theoretical condensate temperature t1 in which the heat exchanger 4 has not deteriorated with the actual condensate temperature T2 at present, and determines the deterioration of the heat exchanger 4 from the difference. Then, if necessary, the deterioration determination of the heat exchanger 4 by the determination means 64 is corrected. As a result, the accuracy of determining the deterioration of the heat exchanger 5 is improved, and the replacement time of the heat exchanger 4 can be determined more accurately.

By using steam for the heating fluid F1, the temperature of water can be rapidly raised by the heat exchanger 4.

The present invention is not limited to the above embodiments, and various additions, changes, or deletions can be made without departing from the gist of the present invention. For example, in the above embodiment, the circulation type hot water supply system has been described, but the present invention can be applied to a hot water supply system other than the circulation type. Further, although the hot water supply system of the above embodiment includes the tank 2 for storing the water W1, the tank 2 may not be provided. Therefore, such things are also included within the scope of the present 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 Judgment means 66 Theoretical condensate temperature calculation means 68 Correction means F1 Heating fluid (steam)
W1 water W2 hot water

Claims (4)

A heat exchanger that produces hot water by exchanging heat between the heated fluid and water,
The theoretical heat exchange amount calculating means for calculating the theoretical heat exchange amount from the value of the sensor for detecting the pressure or temperature provided in the heating fluid supply passage for supplying the heating fluid to the heat exchanger and the opening degree of the heating fluid control valve. When,
A heat exchange amount calculating means for calculating 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 derived from the heat exchanger.
A hot water supply system including a determination means for determining deterioration of the heat exchanger from the theoretical heat exchange amount and the heat exchange amount. In the hot water supply system according to claim 1, further
A theoretical condensate temperature calculating means for calculating the theoretical condensate temperature at the outlet of the heat exchanger from the value of the sensor, the opening degree of the heating fluid control valve, the flow rate and temperature of the water supplied to the heat exchanger.
A hot water supply system comprising a correction means for correcting the determination of deterioration of the heat exchanger from the theoretical condensate temperature and the condensate temperature at the outlet of the heat exchanger. In the hot water supply system according to claim 1 or 2, the hot water supply system is a pressure sensor in which the sensor measures the pressure of the heated fluid in the heated fluid supply passage. The hot water supply system according to any one of claims 1 to 3, wherein the heating fluid is steam.

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