JP2011085347A - Hot water supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hot water supply device capable of performing an automatic drainage process by surely determining completion of draining without adding a dedicated device. <P>SOLUTION: A control device 40 memorizes times until two temperature detecting means 10f4, 10f5 among a plurality of temperature detecting means 10f1-10f5, respectively detect maximum temperatures, after opening a drain valve 18a in executing an automatic draining mode, calculates a time Fintime necessary for completely draining the hot water/water in a hot water storage tank 10 on the basis of the difference of two memorized times, a volume B of the hot water storage tank 10 between two temperature detecting means 10f4, 10f5, and the total volume A of the hot water storage tank 10, and closes the drain valve 18a on the basis of the calculated time Fintime. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a hot water storage type hot water supply apparatus that boils hot water and stores the hot water and uses the stored hot water for hot water supply.

  As a conventional hot water supply apparatus, for example, one described in Patent Document 1 is known. This hot water supply apparatus can automatically drain hot water in a hot water storage tank in order to prevent freezing and decay of hot water when the user does not use the hot water in the hot water storage tank for a long period of time.

  Specifically, when a drain instruction from the user is input to the remote controller, the water tap is closed, the relief valve provided on the upper side of the hot water storage tank is opened, and the drain tap is opened. Then, the timing of the drainage timer is started, and when a predetermined time has elapsed, it is considered that all the hot water in the hot water storage tank has been drained, and the drainage mode is terminated.

  Further, in another embodiment, a drainage sensor is provided in the drainage pipe, the presence or absence of drainage in the drainage mode is directly detected by the drainage sensor, and drainage is completed when the drainage sensor no longer detects drainage. Judgment is made to end the drainage mode.

JP 2007-64581 A

  However, in Patent Document 1, since completion of drainage is determined after a lapse of a predetermined time, for example, if the relief valve is not opened reliably for some reason, the drainage speed becomes slow, and the predetermined time has elapsed. However, drainage will not be completed, and it may be erroneously judged that drainage is complete.

  Further, in the case where a running water sensor is provided, it is possible to determine the completion of reliable drainage by detecting the state of direct drainage, but an extra device called a running water sensor is required, which is disadvantageous in terms of cost.

  In view of the above problems, an object of the present invention is to provide a hot water supply apparatus that can perform automatic drainage processing by determining completion of reliable drainage without requiring addition of dedicated equipment.

In order to achieve the above object, the present invention employs the following technical means. That is, in the invention according to claim 1, in the hot water supply device, a hot water storage tank (10) for storing hot water boiled by the heating means (20),
A plurality of temperature detection means (10f1 to 10f5) provided in a vertical direction of the hot water storage tank (10) for detecting the temperature of the hot water in the hot water storage tank (10);
A drain pipe (18) provided at a lower portion of the hot water storage tank (10) for draining hot water in the hot water storage tank (10);
A drain valve (18a) for opening and closing the drain pipe (18);
An open valve (12b) provided at an upper part of the hot water storage tank (10) and opened when draining hot water in the hot water storage tank (10);
A control device (40) for controlling the opening / closing operation of the drain valve (18a) when executing an automatic drain mode for automatically draining hot water in the hot water storage tank (10),
When the automatic drain mode is executed, the control device (40) opens the drain valve (18a) and then sets the two temperature detection means (10f4, 10f5) to the maximum among the plurality of temperature detection means (10f1 to 10f5). The time until the temperature is detected is stored, the difference between the two stored times, the volume (B) of the hot water storage tank (10) between the two temperature detection means (10f4, 10f5), and the hot water storage tank (10 ) Is calculated from the total volume (A) of the hot water storage tank (10) from the total volume (A) of the hot water storage tank (10), and drainage is performed based on the calculated time (Fintime). It is characterized by closing the valve (18a).

  In a hot water supply device (100) provided with a hot water storage tank (10), hot water is normally stored on the upper side of the hot water storage tank (10) and low temperature hot water is stored on the lower side by natural convection. And the several temperature detection means (10f1-10f5) arrange | positioned in the vertical direction of a hot water storage tank (10) detects the temperature of the hot water in each position. In the automatic drain mode, when the drain valve (18a) is opened together with the open valve (12b), the hot water in the hot water storage tank (10) is drained from the drain pipe (18), and the water level is lowered. As the water level decreases, hot hot water in the hot water storage tank (10) passes through the respective positions of the plurality of temperature detection means (10f1 to 10f5).

  Therefore, the time until two temperature detection means (10f4, 10f5) of the plurality of temperature detection means (10f1 to 10f5) each detect the maximum temperature of hot water is stored, and the time difference until the maximum temperature detection is stored. By calculating the actual time required for hot water to actually pass through the two temperature detection means (10f4, 10f5). That is, the actual drainage time required for draining hot water for the volume (B) of the hot water storage tank (10) between the two temperature detection means (10f4, 10f5) can be grasped. is there. Since the volume (B) of the hot water storage tank (10) between the two temperature detection means (10f4, 10f5) is known, the total volume (A) of the hot water storage tank (10) is calculated by proportional calculation from the above actual drainage time. ) It is possible to calculate the total drainage time (Fintime) required to completely drain the hot water.

  Accordingly, it is possible to complete an accurate automatic drainage mode based on an actual drainage state by determining that drainage is completed with this total drainage time (Fintime) and closing the drainage valve (18a). As described above, according to the present invention, it is possible to complete the automatic drainage mode based on the accurate total drainage time without using a dedicated device such as the flowing water sensor described in Patent Document 1. Furthermore, since the drain valve (18a) is opened only while it is required for drainage, and the drain valve (18a) is closed together with the completion of the automatic drain mode, the drain valve (18a) is opened after the drainage is actually completed. As a sanitary hot water supply device (100), it is possible to shorten the time in which the state remains, and to prevent inadvertent entry of foreign matter into the hot water storage tank (10) from the drain valve (18a). Can be used.

In the invention according to claim 2, in the hot water supply apparatus,
The control device (40) detects the maximum detected by the lowest temperature detection means (10f5) among the plurality of temperature detection means (10f1 to 10f5) after opening the drain valve (18a) during execution of the automatic drainage mode. The temperature is stored, and the drain valve (18a) is closed when the temperature drop from the stored maximum temperature is equal to or higher than a predetermined temperature.

  After detecting the maximum temperature, the lowermost temperature detection means (10f5) comes into contact with the air in the hot water storage tank (10) after passing hot water, and the temperature detected by the lowermost temperature detection means (10f5) is It decreases with time. The temperature drop from the maximum temperature increases with time. During this time, the hot water reaches the bottom from the position of the lowest temperature detection means (10f5), and the drainage is completed. By grasping in advance the relationship between the time from the water level of the temperature detection means (10f5) at the bottom to the completion of drainage and the amount of temperature decrease, it is possible to know how many times the temperature decrease has been drained. can do.

  Therefore, the temperature drop at the completion of drainage is set as a predetermined temperature in advance, and when the temperature drop exceeds the predetermined temperature, the drain valve (18a) is closed to complete the accurate automatic drainage mode. . Thus, in the present invention, the automatic drainage mode can be completed based on the temperature drop of the lowest temperature detection means (10f5) without requiring a dedicated device such as the flowing water sensor described in Patent Document 1. It becomes. Furthermore, since the drain valve (18a) is opened only while it is required for drainage, and the drain valve (18a) is closed together with the completion of the automatic drain mode, the drain valve (18a) is opened after the drainage is actually completed. Time can be shortened, and foreign matter can be prevented from inadvertently entering the hot water storage tank (10) from the drain valve (18a) and used as a sanitary hot water supply device (100). can do.

  In the invention according to claim 3, the control device (40) determines whether the initial maximum temperature and the initial minimum temperature detected by any one of the plurality of temperature detection means (10 f 1 to 10 f 5) when executing the automatic drainage mode. When the difference is equal to or smaller than a predetermined value, the drain valve (18b) is closed when a predetermined time elapses after the drain valve (18a) is opened.

  When the difference between the initial maximum temperature and the initial minimum temperature is equal to or less than a predetermined value, it is difficult to detect the maximum temperature. Therefore, in such a case, it is possible to determine the completion of drainage based on a predetermined time in an emergency evacuation and complete the automatic drainage mode.

  As in the fourth aspect of the invention, the control device (40) may substitute the initial minimum temperature with the outside air temperature.

  In the invention described in claim 5, the open valve (12b) is opened together with the drain valve (18a) by the control device (40) and closed together with the drain valve (18a) when executing the automatic drain mode. It is characterized by. Thereby, execution of automatic drainage mode including opening and closing of an open valve (12b) is attained.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows a corresponding relationship with the specific means of embodiment description mentioned later.

It is a schematic diagram which shows the whole structure of the hot water supply apparatus in 1st Embodiment. It is a flowchart which shows the process at the time of automatic drainage mode execution of the hot water supply apparatus in 1st Embodiment. It is a time chart which shows the hot water temperature in each thermistor in 1st Embodiment. It is a flowchart which shows the process at the time of automatic drainage mode execution of the hot water supply apparatus in 2nd Embodiment. It is a time chart which shows the hot water temperature in each thermistor in 2nd Embodiment.

  A plurality of modes for carrying out the present invention will be described below with reference to the drawings. In each embodiment, parts corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals, and redundant description may be omitted. When only a part of the configuration is described in each mode, the other modes described above can be applied to the other parts of the configuration. Not only combinations of parts that clearly show that combinations are possible in each embodiment, but also combinations of the embodiments even if they are not specified unless there is a problem with the combination. Is also possible.

(First embodiment)
The hot water supply apparatus in 1st Embodiment is demonstrated using FIGS. 1-3. 1 is a schematic diagram showing the overall configuration of a hot water supply device 100 using the heat pump unit 20, FIG. 2 is a flowchart showing processing during execution of an automatic drain mode of the hot water supply device, and FIG. 3 is hot water in each of the thermistors 10f1 to 10f5. It is a time chart which shows temperature Th1-Th5.

  The hot water supply device 100 is a hot water storage type used for general household use, and stores high temperature hot water generated by the heat pump unit 20 in the hot water storage tank 10 (boiling operation), and uses the stored hot water for hot water supply. As hot water, it is supplied to kitchens, washrooms, baths, etc. (hot water supply operation, hot water operation).

  As shown in FIG. 1, a hot water supply apparatus 100 includes a hot water storage tank 10, various pipes 11, 11a, 11b, 12, 12a, 15, 16, 18, a heat pump unit 20, a bathtub 30, control devices 40 and 41, and each thermistor 10f1. -10f5 etc.

  The hot water storage tank 10 is a container for storing hot water for hot water supply, and is made of a metal having excellent corrosion resistance (for example, made of stainless steel). It can be kept warm across. In this embodiment, the total capacity of the hot water storage tank 10 is 185L.

  The hot water storage tank 10 has a vertically long shape, and an introduction port 10a is provided on the bottom surface thereof. A water supply pipe 11 for supplying hot water (tap water) into the hot water storage tank 10 is connected to the introduction port 10a. In addition, the water supply pipe 11 is provided with a pressure reducing check valve (not shown) for adjusting the water pressure of the hot water to be introduced to a predetermined pressure and preventing the back flow of the hot water in the case of water interruption or the like. On the other hand, a lead-out port 10b is provided at the uppermost part of the hot water storage tank 10, and a high-temperature take-out pipe 12 for leading out high-temperature hot water stored in the hot water storage tank 10 is connected to the lead-out port 10b.

  At the lower part of the hot water storage tank 10, there is provided a discharge port 10 c for discharging the lowermost hot water in the hot water storage tank 10 to the heat pump unit 20 described later, and at the upper part of the hot water storage tank 10, the heat pump unit 20. A suction port 10d through which hot water discharged from the side flows into the interior is provided. The discharge port 10c and the suction port 10d are connected by a circulation circuit 21, and a part of the circulation circuit 21 is disposed in the heat pump unit 20 (water refrigerant heat exchanger).

  On the outer wall surface of the hot water storage tank 10, a plurality (five in this example) of thermistors 10f1 to 10f5 as temperature detecting means for detecting the amount of hot water stored and the temperature of hot water storage are arranged at substantially equal intervals in the vertical direction (top to bottom direction). The thermistors 10f1 to 10f5 are configured to output a temperature signal at each water level of hot water or hot water filled in the hot water storage tank 10 to the control device 40 described later. The thermistors 10f1 to 10f5 are disposed at positions 20L, 50L, 90L, 130L, and 165L from the upper end side of the hot water storage tank 10 when the total volume of the hot water storage tank 10 is 185L as described above, for example.

  Therefore, based on the temperature signals from the thermistors 10f1 to 10f5, the control device 40 determines the boundary position between the hot water heated in the upper part of the hot water tank 10 and the hot water before being heated in the lower part of the hot water tank 10. Can be detected. For example, if the detected temperature of a certain thermistor exceeds a predetermined temperature (for example, 50 ° C.) that can be used as the amount of stored hot water, the controller 40 can supply hot water that can be used for hot water supply from the top of the hot water storage tank 10 to the position of the thermistor. Judge that it has accumulated.

  Of these thermistors 10 f 1 to 10 f 5, the thermistor 10 f 1 is provided on the upper outer wall surface of the hot water storage tank 10, and is located at the uppermost part in the hot water storage tank 10 that is the temperature of the hot water sucked into the high temperature take-out pipe 12. It also has a function of a hot water thermistor that detects the hot water temperature. Further, the thermistor 10f5 is provided on the lower outer wall surface of the hot water storage tank 10, and also has a thermistor function for confirming the boiling state during the heating operation described later.

  The heat pump unit 20 is a heating unit that heats low temperature hot water at the lower side of the hot water storage tank 10 and stores high temperature hot water from the upper part of the hot water storage tank 10, and uses a low critical temperature carbon dioxide (CO 2) as a refrigerant. A cycle and a water supply pump 22 installed in the circulation circuit 21 are provided. According to the supercritical heat pump, hot water having a temperature higher than that of a general heat pump cycle (for example, about 85 ° C. to 90 ° C.) can be stored in the hot water storage tank 10.

  The heat pump cycle is composed of an electric compressor (not shown), a water refrigerant heat exchanger, an electric expansion valve, an air heat exchanger, and an accumulator, which are sequentially connected by refrigerant piping, and its operation is for a heat pump (not shown). It is controlled by a control device.

  The water-refrigerant heat exchanger includes a refrigerant passage through which refrigerant flows and a water passage through which hot water circulating through the circulation circuit 21 flows, and is discharged from the discharge port of the compressor and flows through the refrigerant passage. The hot water is boiled by heating the hot water flowing through the water passage (circulation circuit 21) with a high-temperature and high-pressure refrigerant.

  The water supply pump 22 is disposed between the discharge port 10c of the circulation circuit 21 and the heat pump unit 20 (water refrigerant heat exchanger). The water supply pump 22 is driven to rotate by an electric motor (not shown) incorporated therein, and discharges low-temperature hot water from the discharge port 10c during hot water boiling operation to store hot water heated in the water-refrigerant heat exchanger. It operates to recirculate to the inlet 10d of the tank 10. The rotation speed of the feed water pump 22 is controlled by a heat pump controller (not shown) so that the outlet water temperature of the water-refrigerant heat exchanger becomes a predetermined target boiling temperature determined under various operating conditions. .

  The water supply pipe 11 is provided with branch water supply pipes 11a and 11b branched from the front portion of the introduction port 10a, and the downstream ends of the branch water supply pipes 11a and 11b are connected to mixing valves 13 and 14 to be described later, respectively. ing.

  A mixing valve 13 is provided at the downstream side joining portion between the high temperature take-out pipe 12 and the branch water supply pipe 11a. The mixing valve 13 is a temperature control valve, and adjusts the opening area ratio (valve opening degree) on each of the high temperature side and the low temperature side so that the hot water extracted from the high temperature extraction pipe 12 and the branch water supply pipe 11a. By adjusting the mixing ratio with the hot water supplied, the temperature of hot water flowing through the hot water supply pipe 15 connected to the downstream side of the mixing valve 13 is adjusted to a set temperature set by the user. The opening degree of the mixing valve 13 is controlled by a control device 40 described later. The hot water supply pipe 15 is a pipe that guides hot water whose temperature is adjusted to a set temperature to a hot water faucet (curan, shower, etc.) as a terminal at the downstream end.

  The high temperature outlet pipe 12 is provided with a high temperature branch pipe 12a that branches from between the outlet 10b and the mixing valve 13. A mixing valve is provided at the downstream junction of the high temperature branch pipe 12a and the branch water supply pipe 11b. 14 is provided. Like the mixing valve 13, the mixing valve 14 is a temperature control valve, and adjusts the opening area ratio (valve opening degree) on each of the high temperature side and the low temperature side to adjust the high temperature taken out from the high temperature branch pipe 12a. Setting in which the user sets the temperature of hot water to be circulated through the bath piping 16 connected to the downstream side of the mixing valve 14 by adjusting the mixing ratio of hot water and hot water supplied from the branch water supply pipe 11b Adjust to temperature. The valve opening degree of the mixing valve 14 is controlled by a control device 40 described later. The bath pipe 16 is connected to the bathtub 30 and is used as a pipe for guiding hot water (hereinafter referred to as bath water) adjusted to a set temperature when hot water is filled, hot water, or hot water in the bathtub 30. Is provided. A hot water solenoid valve 17 for opening and closing the bath pipe 16 is provided in the middle of the bath pipe 16, and the valve opening degree of the hot water solenoid valve 17 is controlled by a control device 40 described later. It has become.

  In the upper part of the hot water storage tank 10, a relief valve 12 b is provided in a pipe branched from the high temperature take-out pipe 12. The relief valve 12 is opened when the pressure in the hot water storage tank 10 exceeds a predetermined pressure, and the internal pressure is released to the outside of the tank. Further, when the hot water in the hot water storage tank 10 is discharged as necessary (details will be described later), the relief valve 12b can be opened by a user's manual operation.

  A drain port 10e is provided on the bottom surface of the hot water storage tank 10, and a drain pipe 18 for draining (discharging) the hot water in the hot water storage tank 10 is connected to the drain port 10e. The water distribution pipe 18 is provided with a drain valve 18 a for opening and closing the water distribution pipe 18. The open / closed state of the drain valve 18a is controlled by a control device 40 described later.

  The control device 40 includes a control panel (remote controller) 41. The control device 40 is mainly composed of a microcomputer, and a built-in ROM (not shown) is provided with a preset control program. The temperature signals from the thermistors 10f1 to 10e5 and the user The mixing valves 13, 14, the hot water solenoid valve 17, and the drain valve 18a are controlled based on an operation signal from the operation panel 41 to be input. In addition, the control device 40 has a timer for timekeeping during automatic drain operation described later.

  The operation panel 41 is provided with a hot water supply set temperature switch, a hot water filling switch, a hot water filling set temperature switch, a drainage switch, and the like as operation switches. The control device 40 is installed in the hot water storage tank 10, and the operation panel 41 is installed in the vicinity of a place where hot water is used such as in a bathroom or kitchen.

  Next, the operation of the hot water supply apparatus 100 configured as described above will be described.

1. The heating operation control device 40 uses an inexpensive late-night power in the midnight time zone (for example, from 23:00 to 7:00 on the next day), compared to the heat pump control device (not shown), and the heat pump unit 20 (heat pump cycle and water pump 22). Instruct the operation of, and boil the hot water for the next day. That is, the control device 40 circulates the hot water at the lower side in the hot water storage tank 10 through the circulation circuit 21 and heats it with the heat pump unit 20, and the generated hot water from the inlet 10 d to the upper side of the hot water storage tank 10. I will save it.

  Specifically, the control device 40 sets the following boiling conditions at the start time of the midnight time zone, and executes the boiling operation based on the boiling conditions. Here, the boiling conditions are a target heat storage amount, a boiling temperature, a boiling heat amount (target heat storage amount-tank hot water storage amount), a boiling time, a boiling start time, and a boiling end time.

  The target heat storage amount is calculated by adding a standard deviation σ to the average usage amount obtained by averaging the usage amount of hot water in a stored predetermined period (for example, the past seven days) to the usage amount of hot water per day. . The target heat storage amount can be viewed as the product of the total volume of the hot water storage tank 10 and the temperature rise width (temperature difference) when boiling the hot water from the hot water.

  The boiling temperature is calculated by adding the temperature of hot water to the value obtained by dividing the target heat storage amount by the total volume of the hot water storage tank 10 (for example, 85 ° C.). The amount of heat stored in the tank hot water is the amount of heat of hot water remaining in the hot water storage tank 10 at 23:00, the temperature of hot water obtained by the thermistors 10f1 to 10f5, the temperature of the hot water supply, and the volume between the thermistors 10f1 to 10f5. And calculated from The boiling start time is determined by back-calculating the boiling time required for boiling from the boiling end time. The boiling end time is here the end time of the midnight time zone (7 o'clock). The boiling time is calculated as the amount of boiling heat / heat pump heating capacity when the amount of heat obtained by subtracting the amount of heat stored in the tank from the target amount of stored heat is used as the amount of boiling heat. The boiling start time is determined by subtracting the calculated boiling time from the end time of the midnight time zone.

  At the boiling start time, the control device 40 operates the heat pump unit 20 to start boiling hot water. When the boiling is finished or when the boiling finish time is reached, the heat pump unit 20 is stopped and the boiling of the hot water is finished. The determination of the completion of boiling is made when the lowest temperature (thermistor 10f5) of the hot water storage tank 10 is equal to or higher than (boiling temperature−predetermined temperature).

2. Hot water supply operation, hot water filling operation When hot water is used in a kitchen or a washroom in the daytime, the control device 40 causes the mixing valve 13 to match the set temperature input by the user from the hot water set temperature switch of the operation panel 41. By adjusting the valve opening degree of the hot water, the hot water of the high temperature take-out pipe 12 taken out from the outlet 10b of the hot water storage tank 10 and the hot water supplied from the branch water supply pipe 11a are mixed to obtain hot water whose temperature is adjusted. The hot water supply pipe 15 supplies the hot water tap.

  In addition, when filling the bath, the control device 40 opens the filling solenoid valve 17 and sets the mixing valve 14 so that it matches the set temperature input by the user from the filling temperature setting switch on the operation panel 41. By adjusting the valve opening, the hot water of the high temperature branch pipe 12a taken out from the outlet 10b of the hot water storage tank 10 and the hot water supplied from the branch water supply pipe 11b are mixed, and the bath is heated as temperature-controlled hot water. It supplies to the bathtub 30 from the piping 16 for work.

3. Automatic drain operation (execution of automatic drain mode)
When the user does not use the hot water supply device 100 for a long period of time, for example, in the winter season, it is necessary to discharge hot water in the hot water storage tank 10 in order to prevent freezing in the tank or to prevent corruption in the tank. Will occur. In such a case, the user first opens the relief valve 12b by manual operation, and inputs the drainage treatment with the drainage switch of the operation panel 41.

  When receiving a signal from the drain switch, the control device 40 executes an automatic drain operation based on the flowchart shown in FIG. During the automatic drain operation, the control device 40 repeatedly rotates the flowchart of FIG. 2 to constantly monitor the state at each step and perform necessary processing. The relationship between the temperatures Th1 to Th5 detected by the thermistors 10f1 to 10f5 and the elapsed times Time1 to Time5 accompanying the temperature detection will be described with reference to FIG.

  First, in step S100 in FIG. 2, among the temperature signals obtained from the thermistors 10f1 to 10f5, a difference ΔT between the maximum temperature (initial maximum temperature) and the minimum temperature (initial minimum temperature) is calculated, and the temperature difference at this time It is determined whether ΔT is larger than a predetermined value Tα. The predetermined value Tα is a threshold value for determining whether or not there is a clear temperature difference between the hot water on the upper side and the lower side in the hot water storage tank 10. If it is determined in step S100 that the temperature difference ΔT is larger than the predetermined value Tα (there is a sufficient temperature difference), the process proceeds to step S110. If it is determined NO, the process proceeds to step S200.

  In step S110, the drain valve 18a is opened. Then, since the relief valve 12b is opened in advance, air can be sucked into the hot water storage tank 10 from outside the upper side, and the hot water in the hot water storage tank 10 is discharged from the water distribution pipe 18. In step S120, a built-in timer is started to start timing.

  In the following steps S130 to S160, the controller 40 detects the temperatures Th4 and Th5 detected by using two thermistors (here, thermistors 10f4 and 10f5) out of the five thermistors 10f1 to 10f5, and accompanying these temperature detections. Processing for the elapsed times Time4 and Time5 is performed.

  That is, in step S130, it is determined whether or not the temperature Th4 detected this time is higher than the previously detected temperature Th4old at the temperature Th4 of the thermistor 10f4 sequentially obtained while turning the flowchart of FIG. And if it determines with temperature Th4 being larger than temperature Th4old, it will progress to step S140. If it is determined NO in step S130, the process proceeds to step S150.

  In step S140, for the elapsed time Time4 accompanying the detection of the temperature Th4, the elapsed time when the temperature Th4 reaches the maximum temperature is stored as Time4max, and the process proceeds to step S150.

  In step S150, as in step S130, it is determined whether or not the temperature Th5 detected this time is higher than the temperature Th5old detected last time in the temperature Th5 of the thermistor 10f5 sequentially obtained while turning the flowchart of FIG. If it is determined that the temperature Th5 is higher than the temperature Th5old, the process proceeds to step S160. If it is determined NO in step S150, the process proceeds to step S170.

  In step S160, for the elapsed time Time5 associated with the detection of the temperature Th5, the elapsed time when the temperature Th5 reaches the maximum temperature is stored as Time5max, and the process proceeds to step S170.

  Here, as shown in FIG. 3, in the hot water storage tank 10 at the start of automatic drainage operation (when the elapsed time is 0), hot water is stored on the upper side by natural convection and low temperature hot water is stored on the lower side. Therefore, the temperatures Th4 and Th5 of the lower thermistors 10f4 and 10f5 are lower than the temperature Th1 of the thermistor 10f1 on the upper side (there is a sufficient temperature difference in step S120). As the hot water in the hot water storage tank 10 is discharged by opening the drain valve 18a, the hot water on the upper side descends (the water level decreases) and reaches each thermistor 10f4, 10f5. The temperatures detected by the thermistors 10f4 and 10f5 increase with time. Further, when the hot water is lowered from the positions of the thermistors 10f4 and 10f5, the thermistors 10f4 and 10f5 come into contact with the air in the hot water storage tank 10, and the temperature Th4 detected by the thermistors 10f4 and 10f5, Th5 decreases with time. Thereby, each thermistor 10f4, 10f5 shows the maximum value of the detected temperature with respect to the elapsed time (determination in steps S130 and 150). The elapsed times when the maximum temperature is shown are Time 4max and Time 5max (determined and stored in steps S140 and 160), respectively.

Returning to FIG. 2, in step S <b> 170, a time Fintime required for discharging all hot water in the hot water storage tank 10 is calculated. Time Fintime is
(Formula 1)
Fintime = (Time5max−Time4max) × A / B + C
Is calculated by Here, A is the total volume of the hot water storage tank 10 (185L), B is the tank volume between the thermistor 10f4 and the thermistor 10f5 (165-130 = 35L), and C is a predetermined margin time (for example, 3 minutes). is there.

  In Equation 1 above, the difference between the two times (Time5max−Time4max) is required for hot water to be actually discharged between the thermistor 10f4 and the thermistor 10f5 (tank volume 35L) in the hot water storage tank 10. Corresponds to the time (4 minutes in FIG. 3). Therefore, by multiplying this time difference by the ratio of the total volume A (185L) of the tank to the tank volume B (35L), the time required until the hot water in the hot water storage tank 10 is completely discharged is calculated. (21 minutes in FIG. 3). Note that the extra time C is added to increase the safety factor for the calculation result.

  Next, in step S180, whether the elapsed time Time from the start of the automatic drain operation is equal to or greater than a predetermined minimum drain time D and whether the elapsed time Time is equal to or greater than the above Fintime If the determination is affirmative, the drain valve 18a is closed in step S190. Here, the minimum drainage time D is set, for example, as the time required for the hot water in the hot water storage tank 10 to be completely discharged when the drainage check is performed in advance with the relief valve 12b fully opened. ing.

  If NO is determined in step S180, the process returns to step S130, and steps S130 to S180 are repeated.

  On the other hand, if it is determined as NO in step S100, the drain valve 18a is opened in step S200, and time counting by a timer is started in step S210. In step S220, it is determined whether or not the elapsed time Time from the start of the automatic drain operation to the present time is equal to or longer than a predetermined time E. If the determination is affirmative, the drain valve 18a is closed in step S190. Here, the predetermined time E is a time required for drainage with sufficient margin for draining the entire volume of the tank. For example, when the drainage check is performed in advance with the relief valve 12b in an insufficiently opened state, It is set as the time required for the hot water to be completely discharged.

  As described above, in the hot water supply apparatus 100 of the first embodiment, the boiling operation, the hot water supply operation, and the hot water filling operation can be performed, and the automatic drain operation can be performed as necessary.

  In the automatic drain operation, the time thermistors 10f4 and 10f5 out of the plurality of thermistors 10f4 and 10f5 each store the time Time4max and Time5max until the maximum temperature of hot water is detected, and the time difference until the maximum temperature is detected. By calculating, it is possible to grasp the actual time required for hot water to actually pass through the two thermistors 10f4 and 10f5. That is, it is possible to grasp the actual drainage time required to discharge the hot water of the tank volume B between the two thermistors 10f4 and 10f5. From the tank volume B between the two thermistors 10f4 and 10f5 and the actual drainage time in this tank volume B, it is required for the hot water of the total volume A of the hot water storage tank 10 to be completely discharged by proportional calculation. The total drainage time Fintime can be calculated.

  Therefore, it is possible to complete an accurate automatic drainage operation based on the actual drainage state by determining that drainage is completed with this total drainage time Fintime and closing the drainage valve 18a. As described above, in this embodiment, it is possible to complete the automatic drainage operation based on the accurate total drainage time without using a dedicated device such as the running water sensor described in Patent Document 1. Furthermore, since the drain valve 18a is opened only while it is required for drainage, and the drain valve 18a is closed together with the completion of the automatic drain operation, the time that the drain valve 18a remains open after the drainage is actually completed. , The inadvertent entry of foreign matter from the drain valve 18a into the hot water storage tank 10 can be suppressed, and the sanitary hot water supply device 100 can be used.

  When the automatic drainage operation is performed, among the temperatures detected by the plurality of thermistors 10f1 to 10f5, when the temperature difference ΔT between the initial maximum temperature and the initial minimum temperature is equal to or less than a predetermined value Tα, the maximum by the thermistors 10f4 and 10f5 is used. Since it becomes difficult to detect the temperature, the automatic drain operation by steps S110 to S190 cannot be performed. Therefore, in such a case, it is possible to determine the completion of drainage based on a predetermined time E in an emergency evacuation manner as in steps S200 to S220 and step S190 and complete the automatic drainage mode. it can.

(Second Embodiment)
FIG. 4 shows a control method of the automatic drain operation according to the second embodiment of the present invention, and FIG. 5 shows hot water temperatures Th1 to Th5 in the thermistors 10f1 to 10f5 with respect to the elapsed time during the automatic drain operation. In the second embodiment, Steps S130 to S180 are changed to Steps S150 to S181 with respect to the first embodiment, and among the plurality of thermistors 10f1 to 10f5, the lowermost thermistor 10f5 detects. The drainage completion determination is performed using the temperature Th5.

  After step S120 in FIG. 4, as in the first embodiment, the temperature Th5 of the thermistor 10f5 obtained sequentially in the course of turning the flowchart of FIG. 4 in step S150 is detected this time Th5 from the previously detected temperature Th5old. It is determined whether or not is large. If it is determined that the temperature Th5 is higher than the temperature Th5old (the maximum temperature is detected), the process proceeds to step S161. If it is determined NO in step S150, the process proceeds to step S181.

  In step S161, the temperature at which the temperature Th5 becomes maximum is stored as the maximum temperature Th5max, and the process proceeds to step S181.

  In step S181, whether the elapsed time Time from the start of the automatic drainage operation to the present time is equal to or greater than a predetermined minimum drainage time D, and (maximum temperature Th5max-current temperature Th5) is a predetermined value. It is determined whether the temperature F (for example, 5 ° C.) or higher is reached. If the determination is affirmative, the drain valve 18a is closed in step S190.

  Here, after detecting the maximum temperature Th5max, the lowermost thermistor 10f5 comes into contact with the air in the hot water storage tank 10 after passing hot water, and the temperature Th5 detected by the lowermost thermistor 10f5 decreases with time. Go (Figure 5). The temperature drop from the maximum temperature Th5max increases with time. During this time, the hot water reaches the bottom from the position of the lowermost thermistor 10f5, and drainage is completed. By knowing in advance the relationship between the temperature level from the water level of the lowermost thermistor 10f5 to the completion of drainage and the temperature drop, it is possible to know how many times the temperature drop has been drained. .

  As described above, in the second embodiment, the temperature drop at the time of completion of drainage is set in advance as the predetermined temperature F, and the automatic drainage is accurately performed by closing the drain valve 18a when the temperature drop exceeds the predetermined temperature F. Operation can be completed. Similarly to the first embodiment, the second embodiment does not require a dedicated device such as the flowing water sensor described in Patent Document 1, and the automatic drain operation is completed based on the temperature drop of the lowermost thermistor 10f5. It becomes possible. Furthermore, since the drain valve 18a is opened only while it is required for drainage, and the drain valve 18a is closed together with the completion of the automatic drain operation, it takes time for the drain valve 18a to remain open after the drainage is actually completed. It can be shortened, can prevent inadvertent entry of foreign matter from the drain valve 18a into the hot water storage tank 10, and can be used as a sanitary hot water supply apparatus 100.

  Note that the temperature drop with respect to the passage of time is greatly affected by the season (outside air temperature), and therefore it is preferable to set a predetermined temperature F corresponding to the difference between the maximum temperature Th5max and the outside air temperature for each season. For example, since the outdoor temperature is high in summer, the difference between the maximum temperature Th5max and the outdoor temperature is small, so the predetermined temperature F is decreased. In winter, the difference between the maximum temperature Th5max and the outdoor temperature is large because the outdoor temperature is low. Therefore, it is preferable to increase the predetermined temperature F.

(Other embodiments)
The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  In the first and second embodiments, the temperature difference ΔT in step S100 is the difference between the maximum temperature and the minimum temperature obtained from the thermistors 10f1 to 10f5, but the minimum temperature may be replaced by the outside air temperature. That is, when the temperature difference ΔT between the upper side and the lower side in the hot water storage tank 10 is viewed, the temperature difference ΔT is the smallest when the hot water in the lower side of the tank is completely cooled and equal to the outside air temperature. This is because it can be assumed.

  Moreover, although the relief valve 12b shall be opened at the time of drainage by a user's manual operation, it is good also as what is controlled by the control apparatus 40 as an electromagnetic valve structure, for example. In this case, the relief valve 12b is opened together with the drain valve 18a in steps S110 and S200 during the automatic drain operation, and the relief valve 12b is closed together with the drain valve 18a in step S190. As a result, it is possible to execute an automatic drain operation including opening and closing of the relief valve 12b.

  Moreover, in the said embodiment, although the control apparatus 40 which controls various components at the time of implementation of automatic drain mode was demonstrated as a single control apparatus, it is not limited to this form. For example, the control device 40 is configured by a tank unit control device that controls each functional component (mixing valves 13, 14, hot water solenoid valve 17, etc.) of the hot water storage tank 10 and a heat pump control device that controls the operation of the heat pump unit 20. You may make it do.

  The automatic drain operation described in the above embodiment is a state in which the control device 40 can issue an execution command for the automatic drain operation by operating a predetermined switch provided on the operation panel 41. The form is not limited. For example, a command for executing an automatic drain operation may be transmitted to each hot water supply device by a centralized control panel capable of centrally managing the operation of a plurality of hot water supply devices installed in an apartment house or the like. .

  Further, the working refrigerant flowing through the heat pump cycle of the heat pump unit 20 is not limited to carbon dioxide, but may be other refrigerants such as Freon. Furthermore, the heating means for boiling the hot water is not limited to the heat pump 20 and may be other means such as an electric heater.

DESCRIPTION OF SYMBOLS 100 Hot-water supply apparatus 10 Hot water storage tank 10f1-10f5 Thermistor (temperature detection means)
18 Drain pipe 18a Drain valve 20 Heat pump unit (heating means)
40 Control device

Claims (5)

A hot water storage tank (10) for storing hot water boiled by the heating means (20);
A plurality of temperature detecting means (10f1 to 10f5) provided in a vertical direction of the hot water storage tank (10) for detecting the temperature of the hot water in the hot water storage tank (10);
A drain pipe (18) provided at a lower portion of the hot water storage tank (10) for draining hot water in the hot water storage tank (10);
A drain valve (18a) for opening and closing the drain pipe (18);
An open valve (12b) provided at an upper part of the hot water storage tank (10) and opened when draining hot water in the hot water storage tank (10);
A control device (40) for controlling the opening / closing operation of the drain valve (18a) when executing an automatic drain mode for automatically draining hot water in the hot water storage tank (10),
The control device (40) opens two drainage valves (18a) during execution of the automatic drainage mode, and then includes two temperature detection means (10f4, 10f5) among the plurality of temperature detection means (10f1 to 10f5). ) Stores the time until the maximum temperature is detected, and the difference between the two stored times and the volume (B) of the hot water storage tank (10) between the two temperature detection means (10f4, 10f5). And the time (Fintime) required until the hot water in the hot water storage tank (10) is completely drained from the total volume (A) of the hot water storage tank (10). The hot water supply apparatus characterized by closing the said drain valve (18a) based on time (Fintime). A hot water storage tank (10) for storing hot water boiled by the heating means (20);
A plurality of temperature detecting means (10f1 to 10f5) provided in a vertical direction of the hot water storage tank (10) for detecting the temperature of the hot water in the hot water storage tank (10);
A drain pipe (18) provided at a lower portion of the hot water storage tank (10) for draining hot water in the hot water storage tank (10);
A drain valve (18a) for opening and closing the drain pipe (18);
An open valve (12b) provided at an upper part of the hot water storage tank (10) and opened when draining hot water in the hot water storage tank (10);
A control device (40) for controlling the opening / closing operation of the drain valve (18a) when executing an automatic drain mode for automatically draining hot water in the hot water storage tank (10),
The control device (40) opens the drain valve (18a) during execution of the automatic drain mode, and then the lowest temperature detector (10f5) among the plurality of temperature detectors (10f1 to 10f5). The hot water supply device is characterized in that the maximum temperature detected is stored and the drain valve (18a) is closed when a temperature drop from the stored maximum temperature is equal to or higher than a predetermined temperature.   In the execution of the automatic drain mode, the control device (40) has a difference between an initial maximum temperature and an initial minimum temperature detected by any one of the plurality of temperature detection means (10f1 to 10f5) being a predetermined value or less. In this case, the hot water supply device according to claim 1 or 2, wherein the drain valve (18b) is closed when a predetermined time elapses after the drain valve (18a) is opened.   The hot water supply device according to claim 3, wherein the control device (40) substitutes the initial minimum temperature with an outside air temperature.   The open valve (12b) is opened together with the drain valve (18a) by the control device (40) and closed together with the drain valve (18a) when the automatic drain mode is executed. The hot-water supply apparatus as described in any one of Claims 1-4.

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