JP2010101527A - Storage type water heater - Google Patents

Abstract

An object of the present invention is to provide a hot water storage type hot water heater that performs optimum drive control of a mixing valve and has a small temperature fluctuation range at the time of hot water discharge.
A hot water storage water heater of the present invention includes a hot water storage tank for storing hot water, heating means for boiling hot water in the hot water storage tank to a high temperature, a tapping pipe for discharging hot water from the hot water storage tank, and a tapping pipe. Supply of hot water to the hot water supply terminal while the heating means is in operation, comprising a mixing means for mixing the high temperature hot water and water, and a flow rate detection means for detecting the flow rate of the hot water supplied from the mixing means to the hot water supply terminal Is not a predetermined time, the mixing ratio of the mixing means is set to a predetermined mixing ratio.
[Selection] Figure 1

Description

  The present invention relates to a hot water storage type water heater having a hot water storage tank for storing high temperature hot water boiled by a heat source.

The conventional control of the mixing valve of the hot water storage type hot water heater performs drive control of the mixing valve using temperature information of a thermistor provided on the downstream side of the mixing valve (see, for example, Patent Document 1). Specifically, feedback control is performed to control the opening of the mixing valve so that the temperature detected by the thermistor downstream of the mixing valve becomes the set temperature.
JP 2007-139345 A

  However, the control of the mixing valve used in the conventional hot water storage type hot water heater is effective when there is no pressure fluctuation in the hot water tank, but mixing is performed when there is a pressure fluctuation in the hot water tank. It had the subject that the temperature fluctuation range in a valve will become large.

  Conventional hot water storage water heaters are equipped with hot water storage tanks for storing hot water, and at night when electricity charges are low or when boiling out when hot water runs out, hot water is generated by the heating means and stored in the hot water storage tank. Driving to save. During heating by the heating means, the hot water temperature in the hot water storage tank rises, so the pressure rises and the pressure of the hot water supplied to the mixing valve becomes higher than the water pressure. Even so, the reason is that the hot water side opening is different between when the heating means is stopped and when the heating means is operating.

  FIG. 4 is a fluctuation image diagram of the mixed hot water temperature of a conventional hot water storage type hot water heater. As shown in FIG. 4, the fluctuation range of the hot water temperature due to the hot water after a certain amount of time has elapsed since the start of the boiling process is larger than the fluctuation range of the hot water temperature due to the hot water immediately after the start of boiling. For this reason, when the user tries to take out hot water from the hot water supply terminal, if the temperature fluctuates to a high temperature side, a temperature significantly higher than the temperature set by the user may come out.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object of the present invention is to provide a hot water storage type hot water heater that performs optimum drive control of a mixing valve and has a small temperature fluctuation range at the time of hot water discharge.

  In order to solve the above-described conventional problems, a hot water storage type water heater of the present invention includes a hot water storage tank for storing hot water, a heating means for boiling hot water in the hot water storage tank to a high temperature, and a tapping pipe for discharging high temperature hot water from the hot water storage tank. And mixing means for mixing the hot water and water supplied from the tapping pipe, and a flow rate detecting means for detecting the flow rate of the hot water supplied from the mixing means to the hot water supply terminal. If there is no supply of hot water to the terminal for a predetermined time, the feed forward control is performed by setting the mixing ratio of the mixing means to the predetermined mixing ratio, so that the hot water temperature fluctuation is predicted in advance and the predetermined mixing ratio is set. The width of the hot water fluctuation when the user takes out the hot water from the hot water supply terminal can be reduced, and the user's feeling of use is not impaired.

The hot water storage type water heater of the present invention is supplied from a hot water storage tank for storing hot water, heating means for boiling hot water in the hot water storage tank to a high temperature, a hot water discharge pipe for discharging hot water from the hot water storage tank, and a hot water supply pipe. A mixing means for mixing high-temperature hot water with water and a flow rate detecting means for detecting the flow rate of hot water supplied from the mixing means to the hot water supply terminal, and after the heating means detects the start of operation, the mixing ratio of the mixing means is set. By performing feed-forward control by setting a predetermined mixing ratio, hot water temperature fluctuations are predicted in advance, and by setting the predetermined mixing ratio, the width of hot water temperature fluctuations when a user discharges hot water from a hot water supply terminal can be reduced. It can be made small and does not impair the user's feeling of use.

  The present invention can provide a hot water storage type hot water heater that performs optimum drive control of the mixing valve and has a small temperature fluctuation range at the time of hot water discharge.

  A hot water storage type water heater according to a first aspect of the present invention includes a hot water storage tank for storing hot water, heating means for boiling hot water in the hot water storage tank to a high temperature, a tapping pipe for discharging hot water from the hot water storage tank, and the tapping pipe. A mixing means for mixing the high-temperature hot water supplied with water and a flow rate detecting means for detecting the flow rate of the hot water supplied from the mixing means to the hot water supply terminal, and when the heating means is in operation, If the hot water is not supplied for a predetermined time, the mixing ratio of the mixing means is set to a predetermined mixing ratio, so that the fluctuation range of the hot water is predicted and the mixing valve is driven to a predetermined mixing ratio in advance. The width of temperature fluctuation when the user takes out hot water from the hot water supply terminal can be reduced.

  The hot water storage type water heater of the second invention, particularly in the first invention, when the heating means is operating, and after hot water from the hot water supply terminal has not been discharged for a predetermined time, By driving the mixing means at a speed faster than the driving speed of the mixing means when the hot water is discharged from a normal hot water supply terminal, the fluctuation width of the hot water can be further reduced.

  A hot water storage type water heater according to a third aspect of the present invention includes a hot water storage tank for storing hot water, heating means for boiling hot water in the hot water storage tank to a high temperature, a tapping pipe for discharging hot water from the hot water storage tank, and the tapping pipe. Mixing means for mixing high-temperature hot water and water supplied, and flow rate detection means for detecting the flow rate of hot water supplied from the mixing means to the hot water supply terminal, and after the heating means detects the start of operation, By changing the mixing ratio of the mixing means to a predetermined mixing ratio, the tapping fluctuation range can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a configuration diagram of a hot water storage type hot water supply apparatus according to Embodiment 1 of the present invention. In FIG. 1, the hot water storage type hot water supply apparatus of the present invention is composed of a heat pump unit 1 as a heating means and a tank unit 2 having a hot water storage tank 3 for storing hot water. First, the heat pump unit 1 will be described. Note that although a heat pump is used as a heating unit in this embodiment, the present invention is not limited to the heat pump, and there is no problem even in a configuration in which hot water is heated using an electric heater instead of the heat pump.

  A heat pump unit 1 that is a heating means of the present embodiment includes a compressor 4 that compresses a refrigerant to form a high-temperature and high-pressure refrigerant, a refrigerant water heat exchanger 5 that exchanges heat between the refrigerant and water to generate high-temperature water, and a refrigerant. A decompression device 6 that decompresses, and a heat pump circuit configured by sequentially connecting an evaporator 7 in which heat is exchanged between the atmosphere and the refrigerant and the refrigerant absorbs heat from the atmosphere in an annular manner through a refrigerant pipe 8. Carbon dioxide is used as the refrigerant, and the refrigerant after being compressed by the compressor 4 exceeds the supercritical pressure, and circulates in the refrigerant pipe as indicated by arrows in FIG. The refrigerant is not limited to carbon dioxide, and there is no problem even if a fluorocarbon refrigerant such as R410A or a hydrocarbon refrigerant such as propane is used.

  Next, the tank unit 2 will be described. The tank unit 2 includes a hot water storage tank 3 for storing hot water, and a plurality of thermistors 50a to 50e as remaining hot water temperature detecting means are attached to the wall surface of the hot water storage tank 3, and the temperature detected by each thermistor is used. Based on this, it is detected how much hot water is present in the hot water storage tank 3. Basically, hot water in the hot water storage tank 3 is boiled up during the night time (from 23:00 to 7:00 the following day) when the electricity rate is low, but the hot water storage is based on the temperatures detected by the thermistors 50a to 50e. When it is judged that the remaining hot water in the tank 3 has become low, even if it is during the daytime, the heat pump unit 1 increases the boiling temperature and the hot water is stored in the hot water storage tank 3 so that the hot water runs out during the daytime. Is preventing.

  In addition, a circulation pump 10 for conveying low-temperature water from the bottom of the hot water storage tank 3 to the refrigerant water heat exchanger 5 in the heat pump unit 1 is provided, and the bottom of the hot water storage tank 3 is driven by driving the circulation pump 10. To the refrigerant water heat exchanger 5.

  Moreover, the high temperature water produced | generated with the refrigerant | coolant water heat exchanger 5 is sent up and down the hot water storage tank 3 by the three-way valve 11 which switches a water flow path. When the temperature of the hot water generated by the refrigerant water heat exchanger 5 is lower than a predetermined temperature, the three-way valve 11 is switched to a direction communicating with the bottom of the hot water storage tank 3 and passes through the lower hot water supply pipe 12 to the bottom of the hot water storage tank 3. Hot water is sent. However, when the temperature of the hot water generated by the refrigerant water heat exchanger 5 is equal to or higher than a predetermined temperature, the three-way valve 11 is switched to a direction communicating with the upper part of the hot water storage tank 3 and passes through the upper hot water supply pipe 13. Hot water is sent to the top of.

  A water supply pipe 15 for supplying water from a water supply source is connected to the water supply port 14 provided at the lower part of the hot water storage tank 3, and the hot water outlet 16 provided at the upper part of the hot water storage tank 3 is connected to the hot water supply terminal at a high temperature. A tapping pipe 17 for supplying water is connected. And the water supply port 14 is in a state where the water pressure from the water supply source is constantly applied, and water is supplied from the water supply port 14 as hot water is discharged from the hot water discharge pipe 17.

  Further, a water supply branch pipe 18 branched from the water supply pipe 15 is provided. The hot water discharge pipe 17 and the water supply branch pipe 18 are connected to an electric mixing valve 19 which is a mixing means, and a user sets with a remote control device 30. Hot water is mixed by the electric mixing valve 19 and sent to the hot water supply terminal 22 so that the temperature is discharged to the hot water supply terminal 22.

  A thermistor 20 serving as a temperature detecting means is disposed downstream of the electric mixing valve 19, and the temperature detected by the thermistor 20 is set by the user when the electric mixing valve 19 is normally driven. The feedback control is performed so that the opening degree of the electric mixing valve 19 is changed so as to achieve the set temperature. A flow rate detection device 21 that is a flow rate detection means for detecting the flow rate is provided downstream of the electric mixing valve 19 to detect the flow rate of hot water sent to the hot water supply terminal.

  The hot water supply terminal 22 is connected to a hot water supply pipe 28 for supplying hot water from the electric mixing valve 19 and a water supply pipe 29 for supplying water from a water supply source. In addition, the water can be further mixed while watching the temperature.

  Next, when the heating means (heat pump unit 1 in the present embodiment) operates to heat the hot water in the hot water storage tank 3, the electric mixing valve 19 is controlled when the user discharges hot water from the hot water supply terminal 22. explain.

While the heating means is in operation, the circulating pump 10 is driven, whereby the low temperature water at the bottom of the hot water storage tank 3 is conveyed to the refrigerant water heat exchanger 5 and receives heat from the high temperature and high pressure refrigerant to become high temperature water. Is stored from the top of the hot water storage tank 3. However, while the heating means is in operation, the hot water is gradually stored in the hot water storage tank 3, and the temperature in the hot water storage tank 3 rises and the pressure in the hot water storage tank 3 also increases. As a result, the hot water pressure applied to the electric mixing valve 19 becomes higher than the water pressure of the low-temperature water supplied from the water supply source via the water supply branch pipe 18.

  FIG. 2 illustrates the difference in opening of the electric mixing valve 19 during the heating operation and when the heating operation is stopped when the predetermined temperature is obtained. As shown in FIG. 2, for example, when the set temperature is set to 40 ° C., the hot water side opening of the electric mixing valve 19 is 50% in a normal state (when the heating operation is stopped), while boiling. During the raising operation (during heating operation), 40 ° C. hot water can be obtained at an opening degree of 40%. That is, it can be seen that during boiling operation, hot water having the same temperature as in normal time can be obtained by narrowing the opening on the hot water side compared with normal time.

  Next, feedforward control of the electric mixing valve 19 in the present embodiment will be described.

  If the first hot water discharged from the hot water supply terminal is detected by the flow rate detection device 21 before the predetermined time has elapsed after the start of the heating operation, it is determined that the pressure in the hot water storage tank 3 has not yet risen, and the electric feedback control is performed by normal feedback control. The opening degree of the mixing valve 19 is controlled.

  However, if hot water from the hot water supply terminal is not detected until a predetermined time has elapsed after the start of the heating operation, it is determined that the pressure in the hot water storage tank 3 has increased, and feedforward control is performed. For example, when the electric mixing valve 19 having the characteristics as shown in FIG. 2 is used, when the hot water is discharged from the hot water supply terminal at a set temperature of 40 ° C. during normal operation, the hot water side opening of the electric mixing valve 19 is 50 %It has become. However, if the hot water from the hot water supply terminal is not detected until a predetermined time (for example, a preset value such as 15 minutes) elapses after the heating operation starts, the pressure in the hot water storage tank 3 is increased. Predictingly, the opening degree of the electric mixing valve 19 is driven to the water side, and the hot water side opening degree of the electric mixing valve 19 is driven to a position where it becomes 40%.

  Then, when the user starts to discharge hot water from the hot water supply terminal 22, normal feedback control is performed to control the opening degree of the electric mixing valve 19 so that the set temperature is reached.

  Further, when the first hot water from the hot water supply terminal is detected by the flow rate detection device 21 before the predetermined time has elapsed after the start of the heating operation, the heating operation is performed even when it is determined that the pressure in the hot water storage tank 3 has not yet increased. When the user temporarily stops the hot water from the hot water supply terminal 22, the pressure in the hot water storage tank 3 is not detected unless the hot water from the hot water supply terminal is detected before the predetermined time elapses from the time when the hot water is stopped. Therefore, the opening degree of the electric mixing valve 19 is driven to the water side, and the hot water side opening degree of the electric mixing valve 19 is driven to a position where it becomes 40%.

  Further, when the hot water is discharged from the hot water supply terminal 22 after the heating means is operating and the hot water from the hot water supply terminal 22 has not been discharged for a predetermined time, the electric mixing valve at the time of normal hot water supply from the hot water supply terminal 22 is used. The electric mixing valve 19 is driven at a speed faster than the driving speed of the motor 19.

  FIG. 3 is a diagram showing the driving speed of the electric mixing valve 19. As shown in FIG. 3, the driving speed of the electric mixing valve 19 is changed according to the time until re-heating, and the temperature detected by the thermistor 20 provided on the downstream side of the electric mixing valve 19 Even when there is a difference with the set temperature, the driving speed is changed so as to increase as the difference increases.

For example, when the set temperature is 40 ° C. and the temperature detected by the thermistor 20 is 35 ° C., the temperature deviation is 5 ° C. Moreover, PPS shown in FIG. 3 represents Pulse / Second, and indicates the driving speed per second. As shown in FIG. 3, the control means provided in the tank unit 2 counts the elapsed time until the start of re-watering, selects the high speed mode when the elapsed time reaches 15 minutes or more, and further detects the current temperature deviation. Is calculated, one stage is selected from a plurality of stages, and the electric mixing valve 19 is controlled at the corresponding driving speed.

  This is because, as shown in FIG. 3, as the elapsed time from the hot water storage operation to the time of re-watering is longer, the temperature rise of the hot water in the hot water storage tank 9 becomes larger and the increase in the internal pressure of the hot water storage tank 9 becomes larger. . As a result, a pressure difference between the pressure of the hot water outlet pipe 17 and the pressure of the water supply branch pipe 18 occurs, and hot hot water is likely to be discharged from the hot water supply terminal 22, so that the electric mixing valve is operated at a higher driving speed than in normal operation. It is necessary to let In addition, the larger the temperature deviation, the faster the difference between the set temperature and the value detected by the thermistor 20 must be reduced. Therefore, the mixing valve is operated at a higher driving speed than when the temperature deviation is small. There is a need. The driving speed shown in FIG. 3 is a predetermined experimental value, and can be changed according to the situation.

As described above, by controlling the driving speed of the mixing valve based on the elapsed time and the temperature deviation, the temperature fluctuation of the overshoot phenomenon or the undershoot phenomenon can be reduced, and more comfortable temperature control can be performed. 2)
The configuration of the hot water storage type water heater in the second embodiment of the present invention is the same as that in the first embodiment, and a description thereof will be omitted. The same parts as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and the description thereof is omitted.

  In the present embodiment, the drive control of the electric mixing valve 19 during the heating operation is set to a predetermined hot water side opening simultaneously with the heating operation. This is controlled by predicting that the pressure of the hot water in the hot water storage tank 3 will surely rise due to the heating operation. By performing the drive control in this way, the temperature at the time of hot water supply from the hot water supply terminal 22 is surely obtained. It is possible to prevent the fluctuation range from being greatly touched.

  Various heat sources such as a heat pump cycle and an electric heater can be used as the heating means of the hot water storage type hot water heater according to the present invention.

The block diagram of the hot water storage type hot water heater in Embodiment 1 of this invention Relationship diagram between mixing ratio and set temperature in the first embodiment Relationship diagram between temperature deviation and hot water stop time and mixing valve control speed in the first embodiment Transition diagram of temperature fluctuation range by control of conventional mixing means

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat pump unit 2 Tank unit 3 Hot water storage tank 11 Three-way valve 12 Lower hot water supply pipe 13 Upper hot water supply pipe 14 Water supply port 15 Water supply pipe 16 Hot water outlet 17 Hot water outlet pipe 18 Water supply branch pipe 19 Electric mixing valve 20 Thermistor 21 Flow rate detection device 22 Hot water supply terminal 30 Remote control device 50a-50e Thermistor (remaining hot water temperature detection means)

Claims (3)

A hot water storage tank for storing hot water, heating means for boiling hot water in the hot water storage tank to a high temperature, a hot water outlet for discharging hot water from the hot water storage tank, and high temperature hot water and water supplied from the hot water pipe are mixed. A mixing means; and a flow rate detecting means for detecting a flow rate of hot water supplied from the mixing means to the hot water supply terminal, and if the hot water supply to the hot water supply terminal is not operated for a predetermined time during the operation of the heating means, the mixing A hot water storage type hot water supply machine characterized in that the mixing ratio of the means is a predetermined mixing ratio. If the hot water is discharged from the hot water supply terminal after the heating means is operating and there is no hot water from the hot water supply terminal for a predetermined time, the speed is higher than the driving speed of the mixing means when the hot water is discharged from the normal hot water supply terminal. The hot water storage type water heater according to claim 1, wherein the mixing means is driven. A hot water storage tank for storing hot water, heating means for boiling hot water in the hot water storage tank to a high temperature, a hot water outlet for discharging hot water from the hot water storage tank, and high temperature hot water and water supplied from the hot water pipe are mixed. A mixing means; and a flow rate detecting means for detecting a flow rate of hot water supplied from the mixing means to the hot water supply terminal, and after the heating means detects the start of operation, the mixing ratio of the mixing means is set to a predetermined mixing ratio. A hot water storage type water heater characterized by

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