JP4658900B2 - Hot water storage hot water supply system - Google Patents

Description

  The present invention relates to a hot water storage hot water supply system that stores hot water (hot water) in a hot water storage tank and supplies hot water using the hot water stored in the hot water storage tank. In particular, it relates to a technique for discharging hot water from a hot water storage tank.

  There is known a hot water storage type hot water supply system in which hot water heated by power generation heat, solar heat or the like is stored in a hot water storage tank, and hot water stored in the hot water storage tank is used to supply hot water.

  In the hot water storage type hot water supply system, hot water is stored in a state where a hot water layer is formed in the upper part of the hot water tank and a hot water (or water) layer is formed in the lower part of the hot water tank. A state in which a high temperature layer and a low temperature hot water are not mixed and a high temperature layer is laminated on a low temperature layer is called a temperature stratification state. For example, when hot water with a low temperature is taken out from the lower part of the hot water tank, the hot water with the low temperature taken out is heated by power generation heat, etc., and the heated hot water is returned to the upper part of the hot water tank, Hot water can be stored in a stratified state. When the temperature stratification state is maintained in the hot water storage tank, hot water having a high temperature can be supplied to the outside even if the amount of heat stored in the entire hot water storage tank decreases.

In a hot water storage type hot water supply system, an operator may work by discharging hot water in a hot water storage tank for system maintenance. For example, Patent Literature 1 discloses a technique for discharging hot water in a hot water storage tank.
The hot water supply system of Patent Document 1 has a discharge path connected to the lower part of the hot water storage tank, a discharge valve for opening and closing the discharge path, and a circulation path for circulating hot water in the hot water storage tank. In this hot water supply system, the hot water in the hot water storage tank is circulated using the circulation path before the hot water in the hot water storage tank is discharged. By circulating, the temperature stratification state is destroyed, hot water having low temperature and hot water having low temperature are mixed, and the maximum temperature of hot water in the hot water storage tank is lowered. Furthermore, in the hot water supply system of Patent Document 1, the hot water flowing through the circulation path is cooled. Thereby, the temperature of the hot water in the hot water storage tank is averaged and lowered. When the temperature of the hot water in the hot water storage tank is uniformly below a predetermined temperature, the discharge valve is opened and discharged from the discharge path.

JP 2005-098639 A

During maintenance, it may not be necessary to drain all of the hot water in the hot water storage tank. That is, if a part of hot water in the hot water storage tank is discharged and the water level in the hot water storage tank is lowered to a necessary water level, maintenance may be possible.
In this case, it is necessary to specify how much the water level has dropped as a result of discharging hot water from the hot water storage tank. However, the technique of Patent Document 1 cannot identify the water level in the hot water storage tank that is being discharged. It cannot be determined whether or not the water level in the hot water storage tank has dropped to a water level at which maintenance can be performed. As a result, there arises a problem that a larger amount of hot water is discharged than necessary, and that maintenance work is started even though the hot water level still remaining in the hot water storage tank is high.
For example, the water level can be detected directly by providing a water level sensor or the like in the hot water storage tank. However, when a water level sensor or the like is provided, there arises a problem that the manufacturing cost of the hot water storage tank increases.

  The present invention has been created in order to identify the water level in the hot water storage tank that is being discharged without providing a water level sensor or the like in view of the above situation. In this invention, the water level in a hot water storage tank is specified from the temperature change in the hot water storage tank which arises with discharge of hot water.

  The hot water storage type hot water supply system of the present invention is a system for supplying hot water using hot water stored in a hot water storage tank. This system is arranged at different heights in the hot water storage tank, the hot water storage tank, each of the temperature detecting means for detecting the ambient temperature, the discharge path for discharging the hot water in the hot water storage tank, and the hot water storage When the hot water in the tank is discharged from the discharge path, the first timing at which the detected temperature of the temperature detecting means arranged at the high level changes and the second timing at which the detected temperature of the temperature detecting means arranged at the low level changes. A water level specifying means for specifying the water level in the hot water storage tank is provided from the timing.

In the hot water storage tank of the system, temperature detecting means are arranged at different heights. For example, a plurality of thermistors are arranged at substantially equal intervals in the vertical direction on the inner wall of the hot water storage tank. The hot water storage tank is provided with a discharge path, and the hot water in the hot water storage tank can be discharged to the outside through the discharge path.
Hot water is stored in the hot water storage tank. If temperature stratification is formed in the hot water storage tank, different temperatures are detected by the temperature detecting means arranged at different heights, and if temperature stratification is not formed in the hot water storage tank, it is arranged at different heights. The detected temperature detecting means detects the same temperature. In any case, when the hot water in the hot water storage tank is discharged from the discharge path, the temperature detected by the temperature detection means in the hot water storage tank changes in order from the higher one.

  FIG. 5 shows an example of the temperature change detected by the two temperature detection means during discharge. (1) of FIG. 5 (a) and (b) represents the temperature change which the temperature detection means arrange | positioned at the high level of a hot water storage tank detects, (2) is arrange | positioned at the low level of a hot water storage tank. A temperature change detected by the temperature detecting means is shown. FIG. 5A shows the temperature change when the temperature stratification is formed, and FIG. 5B shows the temperature change when the temperature stratification is not formed.

As shown in FIG. 5A, when temperature stratification is formed in the hot water storage tank, the lower temperature detecting means detects a temperature T2 lower than the higher temperature detecting means. On the other hand, as shown in FIG. 5 (b), if temperature stratification is not formed in the hot water storage tank, the lower temperature detecting means detects the same temperature T1 as the higher temperature detecting means.
When the hot water stored in the hot water storage tank is discharged through the discharge path, the water level in the hot water storage tank decreases. That is, the hot water that has been in contact with the higher temperature detecting means gradually descends downward. The high temperature detecting means exposed to the air is cooled by being exposed to the outside air, and the temperature detected by the high temperature detecting means changes in the descending direction from T1 ((a) and (b) of FIG. See 1)).
On the other hand, the temperature detected by the lower temperature detection means changes in the upward direction when there is temperature stratification at the start of discharge when the hot water level above the hot water storage tank decreases. It changes in the descending direction (see (2) in FIG. 5A). If there is no temperature stratification at the start of discharge, the temperature detected by the lower temperature detection means changes downward when the water level in the hot water storage tank drops and the lower temperature detection means is exposed to the outside air. (Refer to (2) in FIG. 5B).
For example, when there is temperature stratification at the start of discharge as shown in FIG. 5 (a), when the hot water of temperature T1 that was above the hot water storage tank has dropped to the height where the lower temperature detecting means is arranged, The temperature detected by the lower temperature detecting means increases from T2 to T1. When the hot water in the hot water storage tank is further discharged and the water level in the hot water storage tank further falls below the height at which the low temperature detecting means is provided, the temperature detected by the low temperature detecting means drops from T1. To go.
On the other hand, as shown in FIG. 5B, when there is no temperature stratification at the start of discharge, the hot water at the temperature T1 that has been in contact with the higher temperature detection means is disposed in the lower temperature detection means. Even if the temperature is lowered to a certain position, the temperature detected by the lower temperature detecting means does not change from T1. When the hot water in the hot water storage tank is further discharged to lower the water level, the lower temperature detecting means does not come into contact with the hot water. The lower temperature detecting means exposed to the outside air is cooled, and the temperature detected by the temperature detecting means decreases from T1.
The higher the temperature of the hot water in the upper part of the hot water storage tank and the larger the temperature difference between the outside air temperature and the hot water in the hot water storage tank, the greater the temperature detected by the temperature detecting means after the start of discharge.

In the present invention, the water level in the hot water storage tank can be specified from the temperature change detected by the plurality of temperature detecting means as described above. For example, it can be seen that the water level in the hot water storage tank is higher than the height of the high temperature detection means until the first timing when the detection temperature of the high temperature detection means drops. Similarly, it can be seen that the water level in the hot water storage tank is higher than the height of the lower temperature detection means until the second timing when the detection temperature of the lower temperature detection means drops. That is, it can be seen that the water level at the first timing is equal to the height of the high temperature detection means, and the water level at the second timing is equal to the height of the low temperature detection means. From this, the water level drop rate can be calculated, and the water level at an arbitrary time can be specified.
The second timing at which the detected temperature of the lower temperature detecting means changes may be the timing at which the detected temperature of the lower temperature detecting means rises. In this case, it can be seen that the lower surface of the high temperature layer forming the temperature stratification at the second timing is equal to the height of the lower temperature detecting means. When the capacity of the high temperature layer is known, the water level at the second timing can be known.
The high temperature detection means and the low temperature detection means may be adjacent to each other, or other temperature detection means may be interposed therebetween. The higher temperature detection means is not limited to the highest temperature detection means. For example, the second and subsequent temperature detection means from the top may be used. In this case, when temperature stratification is formed, a phenomenon in which the detection temperature of the higher temperature detection means increases may be obtained. In this case, the timing when the temperature rises may be set as the first timing. In this case, it can be seen that the lower surface of the high temperature layer forming the temperature stratification at the first timing is equal to the height of the higher temperature detecting means. The lower surface of the high temperature layer forming the temperature stratification at the first timing is equal to the height of the higher temperature detection means, and the lower surface of the high temperature layer forming the temperature stratification at the second timing is the height of the lower temperature detection means. If they are found to be equal, the water level drop rate can be calculated, and the water level at any point in time can be specified.
The water level in the hot water storage tank can be specified by using the timing at which the temperature detected by the plurality of temperature detecting means changes. The timing may be a timing when the temperature rises or a timing when the temperature falls, and can be used in various combinations. In short, any timing that can identify a change in water level between two timings may be used, and any combination of two timings may be used.

The hot water storage type hot water supply system of the present invention includes a timer for measuring elapsed time, and the water level specifying means includes the elapsed time from the first timing to the second timing measured by the timer, the high level and the low level. from the capacity of the hot water storage tank which is located between the, the discharge rate from the hot water storage tank is calculated, and the elapsed time from the start of discharge, the discharge rate is calculated to identify the water level in the hot water storage tank It is characterized by that .

As described above, the first timing and the second timing may be a temperature rise timing or a temperature fall timing. In the water level specifying means, the discharge rate from the hot water storage tank is calculated from the elapsed time from the first timing to the second timing and the capacity of the hot water storage tank between the temperature detection means detecting the temperature change at those timings. For example, the same temperature change ΔT is detected by the lower temperature detection means shown in (2) from the first timing when the temperature drop of ΔT is detected by the higher temperature detection means shown in (1) of FIG. The discharge speed can be calculated from the elapsed time t1 until the second timing and the capacity of the hot water storage tank between the temperature detection means.
For example, the water level specifying means can specify the water level by subtracting the discharge amount obtained by multiplying the elapsed time from the start of discharge and the discharge speed from the total capacity of the hot water storage tank.

  The hot water storage type hot water supply system according to the present invention includes a discharge amount setting means for setting a discharge amount from a hot water storage tank in advance, and a water level specified by the water level specifying means is a discharge amount set in the discharge amount setting means. It is preferable to provide means for closing the discharge path when it becomes equal to the water level at the time of discharge.

  According to this system, the discharge is terminated when the water level specified by the water level specifying means falls below the water level when the discharge amount set by the discharge amount setting means is discharged. The operator does not need to monitor the water level change in the hot water storage tank. For example, if the part of the system to be maintained and the corresponding water level in the hot water storage tank are known in advance, the hot water in the hot water storage tank can be lowered to a desired water level by the discharge amount setting means. This discharge amount setting means may be capable of inputting a discharge amount or a desired water level by an operator's operation.

  The hot water storage type hot water supply system of the present invention includes a heating circulation path for returning hot water in the hot water storage tank to the upper part of the hot water storage tank, and heating means for heating the hot water flowing through the heating circulation path, and is disposed at the top. If the temperature detected by the temperature detecting means that does not satisfy the predetermined temperature condition, the temperature detected by the temperature detecting means arranged at the uppermost level is a temperature that satisfies the predetermined temperature condition. It is preferable to start discharging after heating the hot water in the hot water storage tank using the circulation path and the heating means.

  When the hot water in the hot water storage tank is discharged through the discharge path, the temperature of the hot water in the hot water storage tank may be low. Alternatively, a sufficient temperature difference may not be formed between the temperatures detected by the two temperature detection means. FIG. 6 is a diagram showing temperature changes detected by a plurality of temperature detecting means in such a case. T1 'in (1) of FIG. 6 is a temperature detected by the temperature detecting means positioned at the high level of the hot water storage tank, and T2 in (2) is a temperature detected by the temperature detecting means positioned at the low level of the hot water storage tank. For example, when (1) and (2) are temperatures detected by two adjacent temperature detecting means, if T1 ′ is low, or if the temperature difference between T1 ′ and T2 is small, the hot water in the hot water storage tank Sufficient temperature change may not be detected during discharge. In such a case, it is possible to form a temperature stratification state in the hot water storage tank by circulating hot water in the hot water storage tank through the heating circulation path and returning the hot hot water heated to the upper part of the hot water storage tank. If a temperature stratification state is formed in the hot water storage tank, the temperature change detected by each temperature detection means during discharge becomes large. According to the present invention, if the temperature detected by the high temperature detecting means in FIG. 6 can be increased from T1 ′ to T1, the water level can be easily specified.

  Whether or not to perform the heating operation is determined by whether or not the temperature detected by the temperature detection means does not satisfy a predetermined temperature condition. The predetermined temperature condition here means that, for example, a temperature difference suitable for detecting a temperature change is formed between the detected temperatures of the two temperature detecting means. Alternatively, it means that the detected temperature of the higher temperature detecting means is sufficiently higher than the outside air temperature.

  In the hot water storage type hot water supply system of the present invention, when the temperature detected by the temperature detection means arranged at the highest level is lower than a predetermined threshold, the temperature detected by the temperature detection means arranged at the highest level is It is preferable to heat the hot water in the hot water storage tank using the heating circulation path and the heating means until the temperature reaches a threshold temperature.

  For example, the water temperature in the hot water storage tank is low, and even if it is discharged as it is, a sufficient temperature change may not be detected. According to the present invention, for example, when the temperature detected by the temperature detecting means disposed at the uppermost position in the hot water storage tank is lower than 60 ° C., the hot water stored until the temperature detected by the temperature detecting means reaches 60 ° C. Heat the water in the tank. As a result, hot water is stored from the top of the hot water storage tank to the height at which the uppermost temperature detecting means is disposed. When the discharge from the hot water storage tank is started, the temperature detected by the temperature detection means arranged below the temperature detection means located at the uppermost position as the level of the hot water is lowered, It changes greatly in order. The water level can be easily identified.

  In the hot water storage type hot water supply system of the present invention, when the temperature difference between the detected temperature of the higher temperature detecting means and the detected temperature of the lower temperature detecting means is smaller than the predetermined temperature difference, the temperature difference becomes the predetermined temperature difference. Until then, it is preferable to heat the hot water in the hot water storage tank using the heating circulation path and the heating means.

  For example, even when the water temperature in the hot water storage tank is low, if there is a sufficient temperature difference (for example, a temperature difference of 10 ° C.) in the hot water storage tank, a temperature change necessary for specifying the water level can be detected. For example, if an effective temperature change can be detected if there is a temperature difference of 10 ° C. between the temperatures detected by two adjacent temperature detecting means, the hot water temperature detected by the higher temperature detecting means and the lower temperature are detected. Heating can be performed until a temperature difference of 10 ° C. exists between the temperature detected by the temperature detecting means. By using the present invention, it is possible to detect a temperature change that can specify the water level without heating the water in the hot water storage tank to a high temperature. The water level can be easily identified.

  The hot water storage type hot water supply system of the present invention includes an outside air temperature detecting means for detecting the outside air temperature, and the temperature detected by the temperature detecting means arranged at the highest level and the outside air temperature detected by the outside air temperature detecting means. When the temperature difference between them is smaller than the predetermined temperature difference, the hot water in the hot water storage tank is heated using the heating circulation path and the heating means until the temperature difference becomes the predetermined temperature difference. Is preferred.

  For example, even if a temperature stratification having a sufficient temperature difference is formed in the hot water storage tank, there is no sufficient temperature difference with the outside air temperature. It may not be cooled by the outside air and a sufficient temperature change may not be detected. According to the present invention, in such a case, the hot water in the hot water storage tank is heated by the heating means until the temperature difference between the temperature detected by the temperature detection means in the hot water tank and the outside air temperature reaches a predetermined value such as 10 ° C., for example. To do. The water level can be easily identified.

According to the hot water supply system of the present invention, it is possible to specify the water level in the hot water storage tank that is being discharged, using the temperature detection means arranged in the hot water storage tank. By using the present invention, the operator can determine whether the water in the hot water storage tank has been discharged to a water level where maintenance can be performed.
If the temperature stratification is formed, the hot water in the hot water storage tank can be discharged without destroying the temperature stratification, and the temperature stratification state can be reproduced even when the water level is raised again. In the case where the lower level hot water is discharged to lower the required water level, it is possible to avoid discharging the hot water wastefully.

The preferred embodiments of the present invention will be described below.
(Mode 1) The control means calculates the accumulated discharge amount from the water level in the hot water storage tank and displays it on the display means.
(Mode 2) The control means calculates and displays the time required to complete the discharge from the discharge speed.
(Embodiment 3) An error history storage means for storing a part where an abnormality is detected in the system is provided, and a part to be maintained is specified from the error history to determine the discharge amount from the hot water storage tank.
(Form 4) It has a memory | storage means which memorize | stores the discharge | emission accumulation amount, and supplies water equal to discharge | emission accumulation amount in a water supply mode.
(Mode 5) The control means has a water supply mode, calculates the amount of water supply and the required time until the water supply is completed, and displays it on the display means.

Embodiments of the present invention will be described with reference to the drawings. Regarding the common parts of the respective embodiments, a duplicate description is omitted. In the first embodiment, a case where all the hot water in the hot water storage tank 11 is discharged will be described, and in the second embodiment, a case where the hot water in the hot water storage tank 11 is lowered to a necessary water level will be described.
(First embodiment)
A hot water storage type hot water supply system 10 according to an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the hot water storage type hot water supply system 10 of this embodiment is connected to a power generation unit 120 and a hot water tap 116. The hot water storage hot water supply system 10 includes a hot water storage tank 11, a heat source device 62, a remote controller 132, and a controller 130.

  The power generation unit 120 is a power generation device using a solid polymer fuel cell. The power generation unit 120 generates power according to the power demand. When generating power, the power generation unit 120 drives the exhaust heat recovery pump 42. When the exhaust heat recovery pump 42 is driven, hot water is sucked out from the bottom of the hot water storage tank 11. The sucked hot water is heated by the generated heat in the exhaust heat recovery heat exchanger 124 and returned from the top to the hot water storage tank 11.

The hot water storage tank 11 stores hot water heated by the heat generated by the power generation unit 120. Hot water stored in the hot water storage tank 11 is used for hot water supply. A temperature stratification is formed inside the hot water storage tank 11, and hot water having a higher temperature than the lower part is stored in the upper part of the hot water storage tank 11. Accordingly, even when the amount of heat stored in the hot water storage tank 11 is small, hot water can be used by discharging the hot water from the upper part of the hot water storage tank 11.
The hot water storage tank 11 is provided with thermistors 12 to 15. The thermistors 12 to 15 are arranged at substantially equal intervals in the height direction of the hot water storage tank 11 and detect the temperature of hot water at each position in the hot water storage tank 11. When the hot water in the hot water storage tank is discharged and the thermistor is exposed to the outside air, the thermistors 12 to 15 detect the temperature of the outdoor air at the respective positions in the hot water storage tank 11. The temperature detected by the thermistors 12 to 15 is output to the controller 130. The temperatures detected by the thermistors 12 to 15 can also be displayed on the display screen of the remote controller 132.

  A supply / discharge path 16 is connected to the bottom of the hot water storage tank 11. A water stop valve 18 is disposed in the supply / discharge path 16. Opening and closing of the water stop valve 18 is controlled by the controller 130. Under normal conditions, the water stop valve 18 is opened. The other end of the water supply / discharge path 16 is connected to the upstream end of the discharge path 30 and the downstream end of the water supply path 20 by a connecting portion 34.

  A downstream end of the discharge path 30 is opened to a discharge port outside the hot water supply system 10. A discharge valve 32 is disposed in the discharge path 30. The opening and closing of the discharge valve 32 is controlled by the controller 130. Normally, the discharge valve 32 is closed.

  The upstream end of the water supply path 20 is connected to a water pipe (not shown). In the water supply path 20, a pressure reducing valve 22, a water supply amount sensor 24, a water supply amount servo 26, and a mixing servo 28 are arranged. The pressure reducing valve 22 adjusts the supply water pressure from the water pipe. The water supply sensor 24 detects the flow rate of tap water flowing through the water supply path 20. A detection signal of the water supply amount sensor 24 is output to the controller 130. The water supply amount servo 26 adjusts the flow rate of tap water flowing through the water supply path 20. The opening degree of the water supply servo 26 is controlled by the controller 130. The mixing servo 28 is disposed at a connection portion between the water supply path 20 and the mixing path 54. The mixing servo 28 adjusts the flow rate ratio of the tap water flowing from the water supply path 20 to the mixing path 54 and the tap water flowing through the water supply path 20 toward the connecting portion 34. The opening degree of the mixing servo 28 is controlled by the controller 130.

The top of the hot water storage tank 11 is connected to a hot water tap 116 by a hot water supply path 50. A hot water supply electromagnetic valve 52 is provided in the hot water supply path 50. When the hot-water tap 116 is opened, the controller 130 opens the hot-water solenoid valve 52. Then, the hot water in the hot water storage tank 11 is pushed up from the bottom toward the top by the supply pressure of the tap water, and the hot water is discharged from the upper part of the hot water storage tank 11 to the hot water supply path 50. Hot water discharged from the hot water storage tank 11 is mixed with tap water flowing from the mixing path 54, adjusted to a desired temperature, and then supplied to the hot-water tap 116.
A negative pressure valve 76 is disposed in the hot water supply path 50. The negative pressure valve 76 is opened when the inside of the hot water storage tank 11 becomes negative pressure (below atmospheric pressure). When the negative pressure valve 76 is opened, the atmosphere flows into the hot water storage tank 11 through the hot water supply path 50.

A heating circulation path 60 is connected to the hot water storage tank 11. The heating circulation path 60 is disposed so as to pass through the heat source unit 62. A thermistor 69 is disposed on the downstream side of the heat source device 62. The thermistor 69 detects the temperature of the hot water that has passed through the heat source device 62. The temperature detected by the thermistor 69 is output to the controller 130.
When the controller 130 drives the circulation pump 64, the hot water in the intermediate portion of the hot water storage tank 11 is sucked out between the thermistors 12 and 13, heated by the heat source device 62, and then returned to the top of the hot water storage tank 11.

The remote controller 132 includes operation switches such as a mode change switch, a discharge switch, and a discharge amount selection switch, and a display board 134. The mode switch is a switch for switching between the normal mode and the discharge mode, and is normally set to the normal mode. The discharge switch is normally OFF. For example, when the operator turns off the discharge switch during the wastewater treatment, the discharge of hot water can be stopped. Furthermore, when it is desired to discharge the hot water in the hot water storage tank 11, the discharge can be restarted by turning on the discharge switch again. When the hot water in the hot water storage tank 11 reaches a desired water level, maintenance can be started.
The discharge amount selection switch can select the discharge amount discharged from the hot water storage tank 11. The remote controller 132 can communicate with the controller 130, and various operation signals are input to the controller 130 by operating each switch. Various kinds of information transmitted from the controller 130 can be displayed on the display board 134. For example, the display board 134 can display the water level at the time of discharge transmitted by the controller 130, the discharge speed, the time required for completion of discharge, the discharge amount selectable by the discharge amount selection switch, and the like. Informing means for notifying the user of the end of the discharge mode may be provided.

  The controller 130 stores a control program. The controller 130 receives an operation signal from the remote controller 132, detection signals from the thermistors 12 to 15, detection signals from various sensors, and the like. The controller 130 processes the input signal with a control program, and controls various pumps, various valves, a heat source machine, and the like. In addition, the controller 130 includes a timer, and can measure an elapsed time during the discharging operation process.

  Next, a process for discharging hot water in the hot water storage tank 11 of the hot water supply system 10 during maintenance or the like will be described. As described above, at the normal time, the water stop valve 18 is open, the discharge valve 32 is closed, and other valves, pumps, and the like are controlled by the controller 130. 2 and 3 show a flowchart of a process for discharging the hot water in the hot water storage tank 11. FIG. 7 shows how the temperature and water level in the hot water storage tank 11 change during the discharge process. 7A shows a case where all the hot water in the hot water storage tank 11 is low when the discharge mode is activated, and FIG. 7B shows a case where all the hot water in the hot water storage tank 11 is high when the discharge mode is activated. And (D) show cases where temperature stratification having a sufficient temperature difference is formed in the hot water storage tank 11 when the discharge mode is activated. (A)-(f) represents the water level change in the hot water storage tank 11 with time. The lines indicated by (1) to (3) represent the positions of the thermistors 12 to 14. The arrows in the figure indicate whether the temperature change detected by the thermistor disposed at the position indicated by the arrow is a change in the upward direction or a change in the downward direction. The hatch at the lower left in the hot water storage tank 11 indicates low temperature hot water, the hatch at the lower right indicates hot water, and the white indicates outside air.

(Ejecting discharge mode)
When the hot water in the hot water storage tank 11 is discharged, the mode is switched from the normal mode to the discharge mode by the user operating the mode switch on the remote controller 132 (step S2 in FIG. 2). An operation signal from the remote controller 132 is input to the controller 130. When the discharge mode is activated, the thermistors 12-15 start detecting the temperatures T12-T15 in the hot water storage tank 11 (step S4). The detected temperatures T12 to T15 are input to the controller 130. The controller 130 constantly monitors the detected temperatures T12-15 of the thermistors 12-15 disposed in the hot water storage tank 11. At this time, the hot water storage tank 11 is in the state shown in (a) of FIGS.

(Heating operation processing)
Next, it is determined whether or not the heating operation process is performed. First, it is determined whether or not the temperature T12 above the hot water storage tank 11 is 60 ° C. or higher (step S6). If the temperature T12 in the upper part of the hot water storage tank 11 is already 60 ° C. or more (in the case of NO in step S6), since the hot water is already stored in the upper part of the hot water storage tank, the heating operation process from step S10 is skipped. Then, the process proceeds to the discharge operation process after step S23. For example, in the state of (a) in (B) to (D) of FIG. 7, since there is high-temperature hot water in the upper part of the hot water storage tank 11, the process proceeds to the discharge operation process without performing the heating operation process. .
If the temperature T12 above the hot water storage tank 11 is lower than 60 ° C. (in the case of YES at step S6), it is determined whether or not there is a sufficient temperature difference in the hot water storage tank (step S8). Specifically, it is determined whether the temperature T12 at the upper part of the hot water storage tank 11 is higher than the temperature obtained by adding 10 ° C. to the intermediate temperature T13 of the hot water storage tank 11 detected at step S4. When there is already a sufficient temperature difference (in the case of YES at step S8), the heating operation process from step S10 is skipped and the process proceeds to the discharge operation process after step S23. When T12 is 60 ° C. or less and there is no predetermined temperature difference between T12 and T13 (NO in step S8), the heat treatment after step S10 is executed. For example, in the state shown in (a) of FIG. 7A, the temperature in the hot water storage tank 11 is low and sufficient temperature stratification is not formed, so it is determined that it is necessary to execute the heating operation process. Is done.

When there is not a sufficient temperature difference between the upper part and the middle part of the hot water storage tank 11 (NO in step S8), the temperature T12 detected by the thermistor 12 is heated so as to be equal to or higher than the predetermined temperature, You need to make a difference. Therefore, the circulation pump 64 is operated, and the hot water in the hot water storage tank 11 is circulated through the heating circulation path 60 (step S10). The predetermined temperature here refers to a temperature having a temperature difference of 10 ° C. from the temperature T13 detected by the thermistor 13.
When the hot water in the hot water storage tank 11 starts to circulate in the heating circulation path 60, the flow rate of the hot water circulating in the heating circulation path 60 is detected, and it is determined whether or not the flow rate reaches a certain amount (step S12). ). When the flow rate detected by the flow rate sensor 66 is 2.7 liters / minute or more (in the case of YES at step S12), the burner 65 is ignited and the combustion operation of the burner 65 is started (step S14). Since the temperature T12 detected at the upper part of the hot water storage tank 11 varies depending on the hot water returned from the heating circulation path 60, it is determined whether the temperature T12 has reached a predetermined temperature (T13 + 10 ° C. in this embodiment) or more (step). S16). When temperature T12 satisfies a predetermined temperature condition (YES in step S16), circulation pump 64 is stopped (step S18). When the circulation pump 64 stops, hot water no longer flows through the heating circulation path 60, and the flow rate detected by the flow rate sensor 66 becomes 2 liters / minute or less (YES in step S20). When the flow rate detected by the flow rate sensor 66 is 2 liters / minute or less (YES in step S20), the burner 65 is extinguished and the combustion operation of the burner 65 is stopped (step S22). At this time, the temperature stratification having a sufficient temperature difference is formed in the hot water storage tank 11, and the process proceeds to the discharge operation process from step S23. For example, in FIG. 7A, the temperature stratification as shown in FIG. 7B is formed by the heating operation process.

(Discharge operation processing)
When the temperature T12 detected by the thermistor 12 satisfies a predetermined temperature condition, the controller 130 closes the water supply amount servo 26 and opens the water stop valve 18 and the discharge valve 32 (step S23). Thereby, discharge of hot water in the hot water storage tank 11 is started. That is, hot water in the hot water storage tank 11 is discharged to the discharge destination via the supply / discharge path 16 and the discharge path 30. When the hot water in the hot water storage tank 11 is discharged, the negative pressure valve 76 is opened by the pressure reduction in the hot water storage tank 11. As a result, the atmosphere flows into the hot water storage tank 11 to prevent the hot water storage tank 11 from being damaged, and the temperature of the portion replaced with air in the hot water storage tank 11 decreases. The controller 130 monitors the passage of time from the start of discharge. When the heating operation process is being performed, the timer of the controller 130 is the time from when the hot water discharge from the hot water storage tank 11 is started until the temperature T12 detected by the thermistor 12 at the start of the discharge is detected by the thermistor 13. t2 (that is, the time taken from (b) to (d) in FIG. 7A) is started to be measured.

  When the discharge from the hot water storage tank 11 is started, it is determined whether or not a temperature drop of 2 ° C. is detected at the temperature T12 detected by the thermistor 12 (step S24). When a temperature drop of 2 ° C. is detected at the temperature T12 (YES in step S24), the thermistor 12 is exposed to the outside air and a temperature drop of 2 ° C. is detected, so the water level in the hot water storage tank 11 is It is specified that the thermistor 12 has been lowered to the height. For example, it is specified that there is a water level at the position shown in FIG. The identified water level is displayed on the display board 134. Further, in this step, the timer of the controller 130 determines the time t1 from when the temperature drop of 2 ° C. is detected by the thermistor 12 until the same temperature change is detected by the thermistor 13 (ie, from (c) of FIG. 7). (E) Time is started to be measured.

When the water level of the hot water storage tank 11 further decreases, it is determined whether or not the detected temperature T13 of the thermistor 13 has reached the detected temperature T12 of the thermistor 12 at the start of discharge. (Step S26). If there is a temperature difference between the temperatures detected by the thermistor 12 and the thermistor 13 at the start of discharge, the detected temperature of the thermistor 13 increases in the timing shown in FIG. 7A, 7C, 7D. To change. When the temperature T13 rises and becomes equal to the temperature T12 (in the case of YES in step S26), it can be seen that the lower surface of the high temperature layer in the hot water storage tank 11 is at the position of the thermistor 13 (FIGS. 7A, 7C, 7C). (See (d) (d)).
Next, it is determined whether or not the heating operation process has been executed before the start of the discharge operation process (step S27). If the heating operation process is executed before the discharge operation process is started (YES in step S27), it is found that the amount of water in the high temperature layer is equal to the capacity of the hot water storage tank 11 between the top of the hot water storage tank 11 and the thermistor 12. In addition, the timer measures the elapsed time t2 (the time taken from (b) to (d) in FIG. 7A). From this, the discharge speed Q2 is calculated from the elapsed time t2 of steps S23 to S26 and the capacity of the hot water storage tank 11 from the thermistor 12 to the thermistor 13 (step S28). The water level is specified by subtracting from the total capacity of the hot water storage tank 11 the capacity obtained by multiplying the discharge speed Q2 obtained by the calculation and the elapsed time from the start of discharge (step S29). By this step, the water level after the timing shown in (d) of FIG. 7 (A) can be specified. The identified water level is displayed on the display board 134. If the heating operation process has not been executed before the start of the discharge operation process (NO in step S27), the amount of water in the high temperature layer is unknown and the discharge rate Q2 cannot be calculated. Steps S28 to S29 are skipped and the process proceeds to step S30 in FIG.

Next, when a temperature drop of 2 ° C. is detected at the detection temperature T13 of the thermistor 13 (YES in step S30 of FIG. 3), the thermistor 13 is exposed to the outside air and a temperature drop of 2 ° C. is detected. From this, it is specified that the water level in the hot water storage tank 11 has dropped to the height of the thermistor 13. It turns out that there exists a water level in the position shown to (e) of FIG. 7 (A)-(D). At this time, the thermistor 13 detects a temperature change similar to the temperature change detected in step S24 (that is, the timing shown in (c) of FIGS. 7A to 7D). Therefore, from the elapsed time t1 from step S24 to step S30 (the time taken from (c) to (e) in FIGS. 7A to 7D) and the capacity of the hot water storage tank 11 between the thermistors 12 and 13, The discharge speed Q1 is calculated (step S31). The water level can be specified from the discharge speed Q1 obtained by the calculation and the capacity of the hot water storage tank 11 (step S32). At this time, the water level may be specified by subtracting the capacity obtained by multiplying the total capacity of the hot water storage tank 11 by the discharge speed Q1 and the elapsed time from the start of discharge, or the discharge speed Q1 and the elapsed time from the water level specified in step S29. You may specify by reducing the capacity | capacitance multiplied by time t2. By this step, the subsequent water level can be specified. The identified water level is displayed on the display board 134.
In any of the cases shown in FIGS. 7A to 7D, the second timing for detecting the same temperature change is shown next from (c) showing the first timing for detecting the predetermined temperature change. (E) and the elapsed time t1 from the first timing to the second timing can be detected. That is, regardless of the temperature state of the hot water in the hot water storage tank 11, the water level in the hot water storage tank 11 after the second timing can be specified by executing at least step S24 and steps S30 to 32.

  When the water level in the hot water storage tank 11 further decreases, it is determined whether or not the detected temperature T14 of the thermistor 14 has reached the detected temperature T12 of the thermistor 12 at the start of discharge. (Step S33). If there is a temperature difference between the temperatures detected by the thermistor 12 and the thermistor 14 at the start of discharge, the detected temperature of the thermistor 14 changes in the upward direction at the timing shown in (f) of FIGS. When the temperature T14 rises and becomes equal to the temperature T12 (in the case of YES at step S33), it can be seen that the lower surface of the high temperature layer in the hot water storage tank 11 is at the position of the thermistor 14 (FIGS. 7A and 7C). (See (f)). By this time, the timer has measured the elapsed time t3 (the time taken from (d) to (f) in FIGS. 7A, 7C, and 7D). From this, the discharge speed Q3 is calculated from the elapsed time t3 in steps S26 to S33 and the capacity of the hot water storage tank 11 from the thermistor 13 to the thermistor 14 (step S34). The water level is specified by subtracting from the total capacity of the hot water storage tank 11 the capacity obtained by multiplying the discharge speed Q3 obtained by the calculation and the elapsed time from the start of the discharge (step S35). By this step, the water level after the timing shown in (f) of FIGS. 7A, 7C, and 7D can be specified. The identified water level is displayed on the display board 134.

  When the water level in the hot water storage tank 11 decreases and the thermistor 14 is exposed to the outside air, the detected temperature T14 of the thermistor 14 changes in the downward direction. Therefore, the operation process executed for the detected temperature T13 of the thermistor 13 in steps S30 to S32 is executed for T14 (step S36). In this step, the discharge rate is calculated from the elapsed time from when the temperature drop of 2 ° C. is obtained by the thermistor 13 until the same temperature drop is obtained by the thermistor 14 and the capacity of the hot water storage tank 11 between the thermistors 13 and 14. Q4 can be calculated. By using the discharge speed Q4, the water level located between the thermistor 14 and the thermistor 15 in FIG. 1 can be accurately specified.

When the detected temperature T15 of the thermistor 15 reaches the detected temperature T12 of the thermistor 12 at the start of discharge, the operation process executed for the detected temperature T14 of the thermistor 14 in steps S33 to S35 is executed for T15 (step S37). Thus, the discharge speed Q5 is calculated from the elapsed time during which the detected temperatures T14 and T15 reach T12 and the capacity of the hot water storage tank 11 between the thermistor 14 and the thermistor 15, and the discharge speed Q5 and the discharge are started. The water level can be specified by subtracting the capacity multiplied by the elapsed time from the total capacity of the hot water storage tank 11. By using the discharge speed Q5, the water level from the thermistors 14 and 15 in FIG. 1 until the detected temperature of the thermistor 15 changes in the descending direction can be accurately specified.
When the thermistor 15 is exposed to the outside air and the detected temperature T15 of the thermistor 15 changes in the downward direction, the operation process executed for the detected temperature T14 of the thermistor 14 in step S36 is executed for T15 (step S38). The discharge speed Q6 is calculated from the elapsed time from when the temperature drop of 2 ° C. is obtained by the thermistor 14 until the same temperature drop is obtained by the thermistor 15 and the capacity of the hot water storage tank 11 between the thermistors 14 and 15. be able to. By using the discharge speed Q6, the water level located below the thermistor 15 in FIG. 1 can be accurately specified.

  In the hot water storage tank 11 of this embodiment, no thermistor is disposed below the thermistor 15. For this reason, when the water level falls below the height of the thermistor 15, the water level in the hot water storage tank 11 becomes zero from the discharge speed calculated lastly in the discharge speeds Q1 to Q6 calculated in steps S28 to S38. Is calculated (step S39). When the calculated required time has elapsed (in the case of YES at step S40), the water stop valve 18 and the discharge valve 32 are closed (step S41). At this time, the end of the discharge mode is displayed on the display board 134. If the notification means is provided, the end of the discharge mode is notified.

In the system 10 of the present embodiment, regardless of the temperature state of the hot water in the hot water storage tank 11, the discharge speed Q1 is calculated by executing at least step S24 and steps S30 to 32, and the discharge speed Q1 is used to perform step S30. Thus, the water level in the hot water storage tank 11 after the timing when the temperature change is detected can be specified. In addition to this, the elapsed time t2 is measured earlier than calculating the discharge speed Q1 from the elapsed time t1 as shown in FIG. 7A, or the elapsed time as shown in FIG. 7D. When the elapsed time t3 is measured earlier than calculating the discharge speed Q1 from t1, the elapsed time from (b) in FIG. 7A as the first timing to (d) as the second timing Using t2 or the elapsed time t3 from (d) in FIG. 7D as the first timing to (f) as the second timing, the discharge speed is calculated at an earlier stage and the water level is specified. Can do.
For example, the water level can be specified by calculating the average speed of the discharge speeds Q1 to Q6. By using a plurality of discharge speeds for specifying the water level, the water level can be specified more accurately.

(Second embodiment)
The hot water storage hot water supply system 10 according to the present embodiment can designate the amount of water discharged from the hot water storage tank 11 using a discharge amount selection switch provided in the remote controller 132. FIG. 4 shows a flowchart of the process of discharging hot water in the hot water storage tank when the discharge amount is selected. As in the first embodiment, in the normal state, the water stop valve 18 is open, the discharge valve 32 is closed, and other valves, pumps, and the like are controlled by the controller 130.

(Ejecting discharge mode)
When the hot water in the hot water storage tank 11 is discharged, the mode is switched from the normal mode to the discharge mode by the operation of the mode switch on the remote controller 132 by the operator (step S42 in FIG. 4). An operation signal from the remote controller 132 is input to the controller 130.
Subsequently, the discharge amount from the hot water storage tank 11 is selected by the operator using the discharge amount selection switch of the remote controller 132 (step S44). At this time, the discharge amount may be input as a numerical value, or a selectable water level level may be displayed on the display board 134 and selected from among them.
When the discharge amount is selected, the target water level for discharge is specified (step S46). For example, if it is specified in step S44 that the operator discharges 120 liters of hot water from the hot water storage tank 11, when the capacity of the hot water storage tank 11 is 160 liters, the target water level is specified to be 40 liters. (See FIG. 1).
From step S48 to step S54, the same operation process as step S4 to step S22 shown in FIG. 2 is repeated. At this point, temperature stratification having a sufficient temperature difference is formed in the hot water storage tank 11. Next, the process proceeds to the discharge operation process from step S56.

(Discharge operation processing)
When the temperature T12 detected by the thermistor 12 satisfies a predetermined temperature condition, the controller 130 closes the water supply amount servo 26 and opens the water stop valve 18 and the discharge valve 32 (step S56). Thereby, discharge of hot water in the hot water storage tank 11 is started. When the hot water in the hot water storage tank 11 is discharged, the negative pressure valve 76 is opened by the pressure reduction in the hot water storage tank 11. As a result, outside air flows into the hot water storage tank 11 to prevent the hot water storage tank 11 from being damaged, and the temperature of the portion replaced with air in the hot water storage tank 11 decreases.
When the discharge from the hot water storage tank 11 is started, the corresponding operation process is executed among the operation processes of Step S24 of FIG. 2 to Step S40 of FIG. 3 according to the temperature change detected by the thermistors 12-15. The discharge speed is calculated (step S57). For example, if the detected temperature T13 of the thermistor 13 drops by 2 ° C., the operation process from step S30 to step S31 in FIG. 3 is executed, and the discharge speed Q1 is calculated. From the calculated drainage speed, the elapsed time, and the capacity of the hot water storage tank 11, the water level at that time is specified (step S58). For example, if the discharge speed Q1 is calculated in step S57, it is specified that the water level is located at a specific height below the position at the timing (e) in FIGS. The
When the water level is specified, it is determined whether the target water level specified in step S46 has been reached (step S60). If the water level specified in step S58 has reached the target water level (YES in step S60), the water stop valve 18 and the discharge valve 32 are closed (step S62). If the target water level has not yet been reached, the operation processing in steps S57 to S58 is repeated. When the specified water level reaches the target water level and the drainage is completed, the end of the discharge mode is displayed on the display board 134, and if the notification means is provided, the end of the discharge mode is notified.

  As described above, in the hot water supply system 10, the hot water in the hot water storage tank 11 is discharged to the discharge destination by the operator switching the mode switch to the discharge mode. The operator can confirm the water level of the hot water in the hot water storage tank 11 displayed on the remote controller 132. The hot water in the hot water storage tank 11 can be set to a desired water level. The hot water in the hot water storage tank 11 lowers the water level while maintaining temperature stratification. Therefore, the thermistor at the position where hot water exists (below the water surface) detects the higher temperature as the upper thermistor, and the thermistor at the position where hot water does not exist (above the water surface) detects the low temperature. The

When the maintenance is completed and the hot water supply system 10 is used again, when the mode changeover switch is switched from the discharge mode to the normal mode and a predetermined water filling operation is performed, tap water is supplied to the hot water storage tank 11 from below. As described above, the hot water remaining in the hot water storage tank 11 after discharging forms a temperature stratification. Moreover, the hot water forming the temperature stratification has a higher temperature than the tap water. Therefore, when tap water is supplied to the hot water storage tank 11 from the lower part, the tap water is stored in the lower part of the hot water storage tank 11. That is, the water level of the hot water forming the temperature stratification is raised while maintaining the temperature stratification. Therefore, the temperature stratification in the hot water storage tank 11 does not disappear even after maintenance. That is, according to the hot water supply system 10, hot water having a high temperature can be supplied to the hot water tap 116 even immediately after maintenance.
In the above embodiment, the heating condition in step S8 is a temperature difference (Claim 6). However, when it is determined in step S6 that T12 <60 ° C., the heating is performed to a predetermined threshold value such as 70 ° C. (Claim 5). Or you may make it heat until a temperature difference with external temperature turns into predetermined temperature differences, such as 40 degreeC, for example (Claim 7).

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
For example, in the hot water supply system 10 described above, the water stop valve 18 and the discharge valve 32 are disposed in the supply / discharge path 16 and the discharge path 30, respectively, but the present invention is not limited to such a form. For example, the water stop valve 18 may not be provided. Even with such a configuration, the hot water in the hot water storage tank 11 can be discharged by closing the water supply amount servo 26 and opening the discharge valve 32. The discharge from the hot water storage tank 11 and the water supply to the hot water storage tank 11 are performed via the supply / discharge path 16, but each may be constituted by a separate pipe.
Further, as shown in FIG. 7D, depending on the temperature state in the hot water storage tank 11, the water level is not always specified in the order of the steps of the discharge operation process. When the detected temperature of any of the thermistors 12 to 15 changes, an operation process corresponding to the temperature change is executed.
The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

It is a figure showing schematic structure of a hot water storage type hot-water supply system. It is a flowchart (1) of the process which discharges the hot water in a hot water storage tank. It is a flowchart (2) of the process which discharges the hot water in a hot water storage tank. It is a flowchart of the process which discharges the hot water in a hot water storage tank when the discharge amount is selected. It is a figure showing the mode of the change of the temperature detected by a temperature detection means. It is a figure showing the mode of the change of the temperature detected by a temperature detection means, when heating operation is performed before discharge start. It is a figure showing a mode that the state in the hot water storage tank at the time of waste water treatment changes.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10: Hot water supply system 11: Hot water storage tanks 12-15: Thermistor 16: Supply / discharge route 18: Water stop valve 20: Water supply route 22: Pressure reducing valve 24: Water supply amount sensor 26: Water supply amount servo 28: Mixing servo 30: Discharge route 32 : Exhaust valve 50: hot water supply path 60: heating circulation path 62: heat source machine 65: burner 116: hot water tap 120: power generation unit 124: exhaust heat recovery heat exchanger 130: controller 132: remote controller 134: display board

Claims (6)

A hot water supply system using hot water stored in a hot water storage tank,
A hot water storage tank,
Wherein are arranged different heights within the hot water storage tank, a plurality of temperature detecting means, each for detecting the temperature of the surroundings,
A discharge path for discharging the hot water of the hot water storage tank,
A timer for measuring elapsed time;
When the hot water in the hot water storage tank is discharged from the discharge path, the detection of the temperature detection means arranged at the low level from the first timing when the temperature detected by the temperature detection means arranged at the high level measured by the timer changes. Elapsed time from the start of the discharge after calculating the discharge speed from the hot water storage tank from the elapsed time until the second timing when the temperature changes and the capacity of the hot water storage tank located between the high and low levels And a water level specifying means for specifying the water level in the hot water storage tank from the calculated discharge speed ,
A hot water storage hot water supply system characterized by comprising: Discharge amount setting means for presetting the discharge amount from the hot water storage tank;
Means for closing the discharge path when the water level specified by the water level specifying means becomes equal to the water level when the discharge amount set in the discharge amount setting means is discharged;
The hot water storage type hot water supply system according to claim 1 , comprising: A heating circulation path for returning the hot water in the hot water storage tank to the upper part of the hot water storage tank;
A heating means for heating the hot water flowing through the heating circulation path;
When the temperature detected by the temperature detecting means arranged at the highest level does not satisfy the predetermined temperature condition, the temperature detected by the temperature detecting means arranged at the highest level becomes a temperature satisfying the predetermined temperature condition. 2. The hot water storage hot water supply system according to claim 1, wherein the hot water in the hot water storage tank is heated using the heating circulation path and the heating means until discharging is started. When the temperature detected by the temperature detecting means arranged at the highest level is lower than a predetermined threshold value, the heating is performed until the temperature detected by the temperature detecting means arranged at the highest level becomes the temperature of the threshold value. The hot water storage hot water supply system according to claim 3 , wherein hot water in the hot water storage tank is heated using a circulation path for heating and the heating means. When the temperature difference between the detection temperature of the higher temperature detection means and the detection temperature of the lower temperature detection means is smaller than the predetermined temperature difference, the heating circulation path and The hot water storage hot water supply system according to claim 3 , wherein hot water in the hot water storage tank is heated using the heating means. It has an outside air temperature detecting means for detecting outside air temperature,
When the temperature difference between the detected temperature detected by the temperature detecting means arranged at the highest level and the outside air temperature detected by the outside air temperature detecting means is smaller than the predetermined temperature difference, the temperature difference is the predetermined temperature difference. The hot water storage hot water supply system according to claim 3 , wherein the hot water in the hot water storage tank is heated using the heating circulation path and the heating means.

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