JP2009287816A - Storage type hot water supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a storage type hot water supply device capable of stably supplying hot water of a target temperature, in the storage type hot water supply device constituted to supply the hot water through a heat exchanger for hot water supply, disposed in a hot water storage tank. <P>SOLUTION: This storage type hot water supply device comprises a heat pump unit 1 for heating the water, the hot water storage tank 21 for storing the warm water heated by the heat pump unit 1, the heat exchanger 22 arranged in the hot water storage tank 21 and for hot water supply for heating the water supplied from the external and supplying hot water, and a mixing valve 31 for hot water supply, mixing the warm water from the heat exchanger 22 for hot water supply and the water supplied from the external. A control section 10 controls an opening of the mixing valve 31 for hot water supply by feedforward control and feedback control on the basis of a hot water supply water outflow temperature and a hot water supply water inflow temperature detected by a hot water supply water-outflow temperature sensor S21, and a hot water supply temperature detected by a hot water supply temperature sensor S22, so that a temperature of the warm water mixed by the mixing valve 31 for hot water supply reaches a hot water supply target temperature. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a hot water storage type hot water supply apparatus.

  Conventionally, as a hot water storage type hot water supply apparatus, there is one that includes a heat pump unit that heats water and a hot water storage tank that stores hot water heated by the heat pump unit, and uses the hot water in the hot water storage tank to perform heating and hot water supply ( For example, refer to JP 2006-329581 A (Patent Document 1).

  In the heat pump type water heater, when hot water is supplied directly using hot water in the tank, the water temperature on the high temperature side can be easily estimated from the tank upper temperature. Such a tank upper temperature does not fluctuate greatly because the heat capacity in the tank is large.

However, in the hot water storage type hot water supply apparatus, while the hot water stored in the hot water storage tank is discharged as it is, a hot water supply heat exchanger is arranged in the hot water storage tank in consideration of hygiene, etc. Another hot water storage type hot water supply apparatus that uses a hot water supply heat exchanger to provide hot water has been proposed. In such a heat pump type water heater using a heat exchanger for hot water supply, since heat is exchanged in the hot water storage tank, the temperature of the hot water discharged from the heat exchanger for hot water supply changes due to external factors such as the flow rate. There is a problem that it is not possible to stably supply hot water.
JP 2006-329581 A

  Accordingly, an object of the present invention is to provide a hot water storage type hot water supply apparatus capable of stably supplying hot water at a target temperature in a hot water storage type hot water supply apparatus configured to discharge hot water via a hot water supply heat exchanger disposed in a hot water storage tank. There is to do.

In order to solve the above problems, the hot water storage type hot water supply apparatus of the present invention is:
A heat pump unit for heating water;
A hot water storage tank for storing hot water heated by the heat pump unit;
A hot water supply heat exchanger that is arranged in the hot water storage tank and heats water supplied from the outside to generate hot water;
A mixing valve for mixing hot water from the hot water heat exchanger and water supplied from the outside;
First temperature detection means for detecting a hot water supply / outflow temperature which is a temperature of hot water from the hot water supply heat exchanger;
Second temperature detection means for detecting a hot water supply water temperature which is a temperature of water supplied from the outside to the hot water supply heat exchanger;
A third temperature detecting means for detecting a hot water supply temperature which is a temperature of hot water mixed by the mixing valve;
Based on the hot water supply / outflow temperature detected by the first temperature detection means, the hot water supply water temperature detected by the second temperature detection means, and the hot water supply temperature detected by the third temperature detection means, the mixing valve And a controller that controls the opening degree of the mixing valve using feedforward control and feedback control so that the temperature of the hot water mixed by the above becomes the hot water supply target temperature.

  According to the hot water storage type hot water supply apparatus having the above-described configuration, the control unit feeds the hot water supply water detected by the first temperature detection means and the feed forward control based on the hot water supply water temperature detected by the second temperature detection means, and the first temperature. The temperature of the hot water mixed by the mixing valve is controlled by controlling the opening degree of the mixing valve using the hot water supply water temperature detected by the detecting means and the feedback control based on the hot water temperature detected by the third temperature detecting means. Make sure that the target hot water temperature is reached. As a result, the feedforward control can quickly respond to a sudden change in the hot water supply / outflow temperature, while a smooth control characteristic can be obtained from the feedback control for a gradual change in the hot water supply / outflow temperature. Thus, in the hot water storage type hot water supply apparatus configured to discharge hot water through the hot water supply heat exchanger arranged in the hot water storage tank, the controllability of the hot water temperature can be improved and the hot water at the target temperature can be stably supplied. Can do.

Moreover, in the hot water storage type hot water supply apparatus of one embodiment,
The control unit
Based on the hot-water supply water temperature detected by the first temperature detection means, the hot-water supply water temperature detected by the second temperature detection means, the hot-water supply target temperature, and the maximum opening of the mixing valve, A mixing valve opening calculating section for determining the opening of the mixing valve when performing the feedforward control;

  According to the embodiment, based on the hot water supply / outflow temperature detected by the first temperature detection means, the hot water supply water temperature detected by the second temperature detection means, the hot water supply target temperature, and the maximum opening of the mixing valve. Therefore, by performing feedforward control using the opening of the mixing valve obtained by the mixing valve opening calculator of the control unit, it is possible to respond quickly to a sudden change in the hot water supply / outflow temperature. Temperature controllability can be improved.

Moreover, in the hot water storage type hot water supply apparatus of one embodiment,
The control unit
A command value correction unit that corrects a command value based on the opening of the mixing valve obtained by the mixing valve opening calculation unit according to an opening characteristic with respect to the command value of the mixing valve;
The command value corrected by the command value correction unit is output to the mixing valve.

  According to the above embodiment, the command value based on the opening of the mixing valve obtained by the mixing valve opening calculating unit is set according to the opening characteristic with respect to the command value of the mixing valve by the command value correcting unit of the control unit. By correcting and outputting the corrected command value to the mixing valve, a desired flow rate ratio can be obtained for a mixing valve having an opening characteristic whose flow rate ratio is not proportional to the opening command value. The command value can be output to the mixing valve.

Moreover, in the hot water storage type hot water supply apparatus of one embodiment,
It has an outside temperature detecting means for detecting outside temperature,
The second temperature detecting means estimates the hot water supply water temperature based on the outside air temperature detected by the outside air temperature detecting means.

  According to the above embodiment, the second temperature detection means estimates the hot water supply water temperature based on the outside air temperature detected by the outside air temperature detection means, thereby supplying water supplied from the outside to the hot water supply heat exchanger. The hot water supply water temperature required for feedforward control can be obtained using the outside temperature detecting means that is normally provided without using the detecting means that directly detects the temperature of the water.

  Further, according to the hot water storage type hot water supply apparatus of one embodiment, a difference between the hot water supply target temperature and the hot water temperature detected by the third temperature detecting means (S22) is obtained, and a PID (proportional / integral) based on the difference is obtained. -It has a mixing valve opening calculation part which calculates | requires the opening degree of the said mixing valve at the time of performing said feedback control by differential control.

  According to the above embodiment, by using the opening degree of the mixing valve obtained by the mixing valve opening degree calculation unit by PID control based on the difference between the hot water supply target temperature and the hot water supply temperature detected by the third temperature detecting means, By performing the feedback control, a smooth control characteristic can be obtained with respect to a gradual change in the hot water supply water temperature.

  As apparent from the above, according to the hot water storage type hot water supply device of the present invention, in the hot water storage type hot water supply device configured to discharge hot water via the hot water supply heat exchanger disposed in the hot water storage tank, the hot water supply at the target temperature is stabilized. Thus, a hot water storage type hot water supply device that can be supplied can be realized.

  Moreover, according to the hot water storage type hot water supply apparatus of one embodiment, the hot water supply / outlet water temperature detected by the first temperature detection means, the hot water supply / intake temperature detected by the second temperature detection means, the hot water supply target temperature, and the mixing valve Based on the maximum opening degree, the feed valve control is performed using the opening degree of the mixing valve obtained by the mixing valve opening degree calculation unit of the control unit. Therefore, the controllability of the hot water supply temperature can be improved.

  Further, according to the hot water storage type hot water supply apparatus of one embodiment, the command value based on the opening of the mixing valve obtained by the mixing valve opening calculating unit is set to the command value of the mixing valve by the command value correcting unit of the control unit. For the mixing valve having an opening characteristic in which the flow rate ratio is not proportional to the command value for the opening, by correcting the opening according to the opening characteristic and outputting the corrected command value to the mixing valve. A command value for obtaining a desired flow rate ratio can be output to the mixing valve, and the flow rate control by the mixing valve can be performed accurately.

  In addition, according to the hot water storage type hot water supply apparatus of one embodiment, the second temperature detection means for estimating the hot water supply water temperature based on the outside air temperature detected by the outside air temperature detection means is used in the hot water supply heat exchanger. Without using a detection means for directly detecting the temperature of the water supplied from the outside, a hot water supply water temperature required for feedforward control can be obtained by using an outside temperature detection means that is usually provided.

  Further, according to the hot water storage type hot water supply apparatus of one embodiment, the mixing valve obtained by the mixing valve opening calculation unit by PID control based on the difference between the hot water supply target temperature and the hot water supply temperature detected by the third temperature detecting means. By performing the feedback control using the opening degree, a smooth control characteristic can be obtained with respect to a gradual change in the hot-water supply water temperature.

  Hereinafter, the hot water storage type hot water supply apparatus of the present invention will be described in detail with reference to the illustrated embodiments.

  FIG. 1 is a circuit diagram showing a configuration of a hot water storage type hot water heater as an example of a hot water storage type hot water heater according to an embodiment of the present invention.

As shown in FIG. 1, this hot water storage type hot water heater includes a heat pump unit 1, a hot water storage part 2, and a heating hot water supply part that supplies hot water to a heater or a water heater (not shown). The heat pump unit 1 uses a CO ₂ refrigerant that has a small global warming potential and does not destroy ozone. Thereby, the hot water temperature by the heat pump unit 1 can be made high (for example, 90 degreeC).

  The heat pump unit 1 includes a compressor 11, a condenser (water refrigerant heat exchanger) 12 having one end (primary side) connected to the discharge side of the compressor 11, and the other end (primary side) of the condenser 12. ), One end connected to the other end of the expansion valve 13, the other end connected to the suction side of the compressor 11, and the evaporator 14 with outside air. And a blower fan 15 to be supplied. The compressor 11, the condenser 12, the expansion valve 13 and the evaporator 14 constitute a refrigerant circuit.

  Further, on the discharge side of the compressor 11, a discharge temperature sensor S1 for detecting the discharge temperature and a pressure sensor (HPS) 16 for detecting the discharge pressure are arranged. Further, an evaporator temperature sensor S2 for detecting the evaporator temperature is arranged in the evaporator 14, and an outside air temperature sensor S3 for detecting the outside air temperature is arranged in the vicinity of the evaporator 14.

  Further, one end of the pipe L11 is connected to the lower part of the hot water storage tank 21, and the other end of the pipe L11 is connected to one end (secondary side) of the condenser 12. A boiling circulation pump 24 for sending water from the bottom of the hot water storage tank 21 toward the condenser 12 is disposed in the pipe L11. One end of the pipe L12 is connected to the other end (secondary side) of the condenser 12 of the heat pump unit 1, and the other end of the pipe L12 is connected to the input side of the boiling three-way valve 25. One end of the pipe L24 is connected to one output side of the boiling three-way valve 25, and the other end of the pipe L24 is connected to one input side of the heating three-way valve 32. Furthermore, one input side of the heating three-way valve 32 is connected to the upper portion of the hot water storage tank 21 via a pipe L35. On the other hand, one end of the pipe L23 is connected to the other output side of the boiling three-way valve 25, and the other end of the pipe L23 is connected to the lower side of the hot water storage tank 21.

  An inlet water temperature sensor S4 for detecting the incoming water temperature is disposed in the pipe L11 on the secondary side upstream of the condenser 12, and a hot water temperature sensor S5 for detecting the outlet water temperature is provided in the pipe L12 on the downstream side of the condenser 12. It is arranged.

  The hot water storage tank 21 has a substantially cylindrical shape surrounded by a heat insulating material (not shown). In the hot water storage tank 21, a hot water supply heat exchanger 22 made of a coiled pipe is disposed. The hot water supply heat exchanger 22 has a lower coil portion 22a and an upper coil portion 22b connected with a predetermined interval. One end of the water supply pipe L21 connected to the hot water storage tank 21 is connected to the water supply port 21a connected to the lower end of the lower coil part 22a, and one end of the hot water supply pipe L22 connected to the hot water storage tank 21 is connected to the upper coil part 22b. Connected to the top. A hot water supply mixing valve 31 is disposed in the hot water supply pipe L22 outside the hot water storage tank 21. One input side of the hot water supply mixing valve 31 and the water supply pipe L21 are connected via a pipe L25. A hot water supply / outflow temperature sensor S21 as an example of a first temperature sensor for detecting the hot water supply / discharge temperature T1 of hot water discharged from the hot water storage tank 21 is disposed upstream of the hot water supply mixing valve 31 in the hot water supply pipe L22. ing. Further, a hot water supply temperature sensor S22 as an example of a third temperature sensor for detecting the hot water supply temperature is disposed downstream of the hot water supply pipe L22 from the hot water supply mixing valve 31.

  The water supplied from the outside through the water supply pipe L21 flows from the lower end side of the lower coil portion 22a toward the upper end side of the upper coil 22b, and enters a water heater (not shown) through the hot water supply pipe L22. Supplied.

  In addition, the hot water storage tank 21 has five temperature sensors S6 to S10 arranged on the side surface so as to be separated from each other in order from the upper side to the lower side. The temperature sensor S6 detects the water temperature in the upper portion of the hot water storage tank 21, and the temperature sensor S8 detects the water temperature in the intermediate portion of the hot water storage tank 21. Further, the water temperature in the hot water storage tank 21 is detected by the temperature sensor S7 between the temperature sensor S6 and the temperature sensor S8. The temperature sensor S10 detects the water temperature in the lower part of the hot water storage tank 21, and the temperature sensor S9 detects the water temperature in the hot water storage tank 21 between the temperature sensor S8 and the temperature sensor S10. In the present embodiment, the five temperature sensors S6 to S10 that detect the water temperature in the hot water storage tank 21 are provided, but it is sufficient that there are four or more temperature sensors that detect the water temperature in the hot water storage tank. By the plurality of temperature sensors, it is possible to determine to what height hot water is stored from above the hot water storage tank.

  An electric heater 23 is arranged in the hot water storage tank 21 and between the lower coil portion 22a and the upper coil portion 22b.

  The hot water storage tank 2, the hot water supply heat exchanger 22, the electric heater 23, the boiling circulation pump 24, the boiling three-way valve 25, and the temperature sensors S 6 to S 10 constitute the hot water storage section 2.

  Next, one end of the pipe L31 is connected to the other input side of the heating three-way valve 32, and the other end of the pipe L31 is connected to the side of the hot water storage tank 21 (the upper coil portion 22b of the hot water storage tank 21 and the electric heater 23). Between).

  The output side of the heating three-way valve 32 is connected to one input side of the heating mixing valve 33, and one end of the pipe L <b> 32 is connected to the output side of the heating mixing valve 33. The piping L32 is provided with a heating temperature sensor S11 and a heating circulation pump 34 in order from the heating mixing valve 33 side. One end of radiators 41, 42,... As an example of a heating terminal is connected to the downstream side of the circulation pump 34 for heating of the pipe L32. Further, one end of a pipe L33 is connected to the lower part of the hot water storage tank 21, and the other ends of the radiators 41, 42,... Are connected to the other end of the pipe L33. A heating return temperature sensor S12 is arranged in the pipe L33. Moreover, the hot water storage tank 21 side and the other input side of the heating mixing valve 33 are connected by a pipe L34 with respect to the heating return temperature sensor S12 of the pipe L33.

  The control unit 10 includes a microcomputer, an input / output circuit, and the like, and includes a mixing valve opening calculating unit 10a that calculates the opening of the hot water mixing valve 31 when performing feedforward control, and a mixing valve opening calculating unit 10a. A command value correction unit 10b that corrects the command value based on the obtained opening degree of the hot water mixing valve 31 in accordance with the opening characteristic with respect to the command value of the hot water mixing valve 31 is provided.

  The control unit 10 controls the compressor 11, the expansion valve 13, the blower fan 15 and the like based on detection signals from the discharge temperature sensor S1, the evaporator temperature sensor S2, the outside air temperature sensor S3, and the pressure sensor (HPS) 16. While controlling, based on the detection signals from the temperature sensors S6 to S10, the heating temperature sensor S11, and the heating return temperature sensor S12, the heating three-way valve 25, the heating three-way valve 32, the heating circulation pump 24, and heating The circulating pump 34 is controlled.

  In the hot water storage type hot water heater having the above configuration, the output side of the boiling three-way valve 25 of the hot water storage section 2 is switched to the pipe L24 side, the compressor 11 of the heat pump unit 1 is driven, and the operation of the blower fan 15 is started. Further, the boiling circulation pump 24 of the hot water storage unit 2 is driven. Then, after the high-pressure gas refrigerant discharged from the compressor 11 is radiated and condensed in the condenser 12 to become liquid refrigerant, the low-pressure refrigerant decompressed by the expansion valve 13 is heated from the outside air by the evaporator 14. Absorbs and evaporates. Then, the low-pressure gas refrigerant evaporated in the evaporator 14 returns to the suction side of the compressor 11. At this time, the water flowing into the secondary side of the condenser 12 from the lower part of the hot water storage tank 21 via the pipe L11 by the boiling circulation pump 24 is heated by the condenser 12 to become hot water close to 90 ° C., and the pipes L12, It returns to the hot water storage tank 21 via the boiling three-way valve 25, the pipe L24, and the pipe L35. In this way, the water in the hot water storage tank 21 is circulated through the boiling circulation pump 24 and the condenser 12, thereby boiling the water in the hot water storage tank 21. The hot water in the hot water storage tank 2 is formed with a hot water layer (temperature distribution) such that the hot water at the upper side is located at the upper side and the hot water at the lower side is located at the lower side.

  Note that, when the heat pump unit 1 is started up or the like, if the hot water coming out of the condenser 12 of the heat pump unit 1 is not yet sufficiently hot, the hot water returns to the upper part of the hot water storage tank 21 via the pipe L24 and the like. Instead, the boiling three-way valve 25 is controlled so as to return to the second boiling return port below the hot water storage tank 21 via the pipe L23. Thus, switching the return port according to the temperature of the hot water may prevent the temperature distribution in the hot water storage tank 21 from being disturbed if hot water that is not sufficiently high is returned to the upper part of the hot water storage tank 21. Because. The switching of the boiling three-way valve 25 is performed based on the output of a tapping temperature sensor S5 provided between the condenser 12 and the boiling three-way valve 25.

  Next, when performing the heating operation, the heating three-way valve 32 of the heating hot water supply unit 3 is switched so that the pipe L31 side and the heating mixing valve 33 side are connected, and the heating circulation pump 34 is driven. Then, the hot water in the intermediate portion of the hot water storage tank 21 flows into the radiators 41, 42,... Via the pipe L31, the heating three-way valve 32, the heating mixing valve 33, and the heating circulation pump 34, respectively. And the return warm water which came out of the said radiator 41,42, ... returns to the hot water storage tank 21 from the lower part of the hot water storage tank 21 via the piping L33.

  Here, based on the detection signals from the temperature sensors S6 to S10, the heating return temperature detected by the heating return temperature sensor S11, and the heating return temperature detected by the heating return temperature sensor S12, the control unit 10 mixes for heating. The valve 33 and the heating circulation pump 34 are controlled. Moreover, you may perform boiling-up by the heat pump unit 1 and heating operation simultaneously.

  Next, when the hot water supply operation is performed, when the hot water supply faucet of the water heater (not shown) is opened, the water supplied by the external water supply pressure is supplied to the water supply pipe L21, the hot water supply heat exchanger 22, and the hot water supply pipe L22. Then, the hot water heated by the hot water supply heat exchanger 22 is supplied to the hot water heater. In addition, at least one of the heating operation or the boiling by the heat pump unit 1 and the hot water supply operation may be performed at the same time, and each operation is not limited.

  During the hot water supply operation, the control unit 10 performs feedforward control based on the hot water supply water temperature T1 and the hot water supply water temperature T2 detected by the hot water supply water temperature sensor S21, and the hot water supply water temperature T1 and the hot water supply detected by the hot water supply water temperature sensor S21. Using the feedback control based on the hot water temperature detected by the temperature sensor S22, the opening degree of the hot water mixing valve 31 is controlled to adjust the temperature of the hot water supplied to the hot water heater to a desired temperature.

The opening degree of the hot water mixing valve 31 is
Opening degree of hot water supply mixing valve 31 = feed forward opening degree × X + feedback opening degree × (1−X)
However, the control ratio X is 0 <X <100
Determined by.

  According to the hot water storage type hot water supply apparatus configured as described above, the control unit 10 detects the feedforward control based on the hot water supply / outflow temperature T1 and the hot water supply / water supply temperature T2 detected by the hot water supply / outflow temperature sensor S21 and the hot water supply / outflow temperature sensor S21. The temperature of the hot water mixed by the hot water mixing valve 31 is controlled by controlling the opening of the hot water mixing valve 31 using the hot water supply water temperature T1 and feedback control based on the hot water temperature detected by the hot water temperature sensor S22. Is set to the hot water supply target temperature. Here, the control part 10 estimates the hot water supply incoming water temperature T2 as a 2nd temperature sensor based on the outside temperature detected by the outside temperature sensor S3.

  As a result, the feedforward control can quickly respond to a sudden change in the hot-water supply water temperature T1, while a smooth control characteristic can be obtained from the feedback control for a gradual change in the hot-water supply water temperature T1. Thus, in the hot water storage type hot water supply apparatus configured to discharge hot water via the hot water supply heat exchanger 22 disposed in the hot water storage tank 21, the controllability of the hot water supply temperature can be improved, and the hot water at the target temperature can be stably supplied. can do.

FIG. 2 is a schematic diagram for explaining the feedforward control of the hot water storage type hot water heater. As shown in FIG. 2, the feed forward of the hot water mixing valve 31 used for feed forward control when the hot water supply temperature T1 discharged from the hot water storage tank 21, the hot water supply water temperature T2, and the hot water supply temperature T3 is set. The opening is determined by the mixing valve opening calculation unit 10a of the control unit 10.
Feed forward opening = (T3−T2) / (T1−T2) × Dmax
(Where Dmax is the maximum opening of the hot water supply mixing valve 31). For example, when the hot water supply / outflow temperature T1 is 70 ° C., the hot water supply / water temperature T2 is 30 ° C., and the hot water supply target temperature T3 is 50 ° C., the feed forward opening of the hot water supply mixing valve 31 may be 50%. In addition, you may obtain | require a feedforward opening degree using not only the said formula but the formula suitably set according to the structure of the hot water storage type heating water heater, etc. FIG.

  In this way, by performing feedforward control using the feedforward opening degree of the hot water supply mixing valve 31 obtained by the mixing valve opening degree calculation unit 10a of the control unit 10, a sudden change in the hot water supply outlet temperature T1 is performed. On the other hand, since it can respond promptly, the controllability of hot water supply temperature can be improved.

  FIG. 3 is a schematic view for explaining feedback control of the hot water storage type hot water heater. As shown in FIG. 3, in the addition symbol 51, a difference is obtained by subtracting the actual hot water temperature from the hot water target temperature, and PID control is performed by the PID control block 52 based on the difference. The feedback opening degree of the mixing valve 31 is obtained. Note that the feedback opening is not limited to the control block shown in FIG. 3, and may be obtained using a control block appropriately set according to the configuration of the hot water storage type hot water heater.

  The command value based on the feedforward opening degree of the hot water mixing valve 31 obtained by the mixing valve opening degree calculation unit 10a is used as the opening degree with respect to the command value of the hot water mixing valve 31 by the command value correction unit 10b of the control unit 10. By correcting according to the characteristics and outputting the corrected command value to the hot water supply mixing valve 31, the hot water mixing valve 31 having an opening characteristic in which the flow rate ratio is not proportional to the feed forward opening command value. On the other hand, a command value for obtaining a desired flow rate ratio can be output to the hot water supply mixing valve 31, and the flow rate ratio control by the hot water supply mixing valve 31 can be performed accurately.

  As a method for determining the opening degree of the hot water supply mixing valve 31 in the control unit 10 as shown in FIG. 4, the opening rate of the hot water supply mixing valve 31 and the flow rate ratio are proportional to each other. Approximating the method of determining the opening degree of the hot water supply mixing valve 31 and the characteristics of the opening degree ratio and the flow rate ratio of the hot water supply mixing valve 31 as shown in FIGS. There is a method of determining the opening degree of the hot water supply mixing valve 31 based on the obtained characteristics.

  FIG. 5 shows a characteristic graph of the opening rate and flow rate (water side flow rate and hot water side flow rate) of the above mixing valve, and FIG. 6 shows the number of mixing valve pulses and flow rate (water side flow rate and hot water side flow rate). The figure which shows the example which sampled numerical data from this characteristic graph is shown. As the hot water supply mixing valve 31 of this embodiment, a pulse drive type mixing valve driven by a stepping motor (not shown) is used.

FIG. 7 shows the relationship between the number of mixing valve pulses and the flow rate ratio based on the numerical data read from the characteristic graph shown in FIG. Here, the flow rate ratio is based on the numerical data of the hot water flow rate and the water flow rate read in FIG.
Flow rate ratio = hot water side flow rate / (hot water side flow rate + water side flow rate) x 100
Ask for. Thereby, an approximate expression (polynomial) of a graph showing the relationship of the number of mixing valve pulses to the flow rate ratio is derived. FIG. 8 shows a graph showing the relationship of the number of mixing valve pulses to the flow rate ratio shown in FIG. 7 and a graph based on the obtained approximate expression (polynomial).

  Further, as an example of the second temperature sensor, the control unit 10 estimates the hot water supply incoming water temperature T2 based on the outdoor air temperature detected by the outdoor air temperature sensor S3, and supplies the hot water supply heat exchanger 22 from the outside. Without using a sensor that directly detects the temperature of the water to be used, a hot water supply water temperature T2 required for feedforward control can be obtained using an outside air temperature sensor that is normally provided.

For example, based on the outside temperature detected by the outside temperature sensor S3,
Feed water temperature = 60% x outside air temperature + 5 ° C
To estimate the feed water temperature (however, 10 ° C. ≦ feed water temperature ≦ 35 ° C.).

  In the above embodiment, the hot water supply water temperature T2 is estimated based on the outdoor air temperature detected by the outdoor air temperature sensor S3. However, a hot water supply water temperature sensor is provided as a second temperature sensor in the pipe L34 and the like. The temperature T2 may be detected directly.

  In the above embodiment, the hot water storage type hot water heater has been described as the hot water storage type hot water heater, but it is needless to say that the hot water storage type hot water heater may be applied without having a heating function.

FIG. 1 is a circuit diagram showing the configuration of a hot water storage type hot water heater as an example of the hot water storage type hot water heater according to the first embodiment of the present invention. FIG. 2 is a schematic diagram for explaining the feedforward control of the hot water storage type hot water heater. FIG. 3 is a schematic diagram for explaining feedback control of the hot water storage type hot water heater. FIG. 4 is a diagram when the opening ratio of the mixing valve and the flow rate ratio are approximated. FIG. 5 is a graph showing a characteristic graph of the opening rate and flow rate (water side flow rate and hot water side flow rate) of the mixing valve. FIG. 6 is a diagram showing an example in which numerical data is sampled from a characteristic graph of the number of pulses of the mixing valve and the flow rate (water side flow rate and hot water side flow rate). FIG. 7 is a diagram showing the relationship of the number of mixing valve pulses to the flow rate ratio based on the numerical data read from the characteristic graph shown in FIG. FIG. 8 is a graph showing the relationship of the number of mixing valve pulses to the flow rate ratio shown in FIG. 7 and a graph based on an approximate expression of the graph.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Heat pump unit 2 ... Hot water storage part 10 ... Control part 10a ... Mixing valve opening calculating part 10b ... Command value correction | amendment part 11 ... Compressor 12 ... Condenser 13 ... Expansion valve 14 ... Evaporator 15 ... Blower fan 16 ... Pressure sensor DESCRIPTION OF SYMBOLS 21 ... Hot water storage tank 22,122 ... Heat exchanger 22a, 122a ... Lower coil part 22b, 122b ... Upper coil part 23 ... Electric heater 24 ... Boiling circulation pump 25 ... Boiling three-way valve 26 ... Sacrificial anode DESCRIPTION OF SYMBOLS 27 ... Pipe 31 ... Mixing valve for hot water supply 32 ... Three-way valve for heating 33 ... Mixing valve for heating 34 ... Circulating pump for heating 41, 42 ... Radiator S1 ... Discharge temperature sensor S2 ... Evaporator temperature sensor S3 ... Outside air temperature sensor S4 ... Water temperature sensor S5 ... Hot water temperature sensor S6 to S10 ... Temperature sensor S11 ... Heating temperature sensor S12 ... Heating return temperature sensor S21 ... Hot water supply / water temperature Degree sensor S22 ... Hot water supply temperature sensor

Claims (5)

A heat pump unit (1) for heating water;
A hot water storage tank (21) for storing hot water heated by the heat pump unit (1);
A hot water supply heat exchanger (22) which is disposed in the hot water storage tank (21) and heats water supplied from the outside to generate hot water;
A mixing valve (31) for mixing hot water from the hot water heat exchanger (22) and water supplied from the outside;
A first temperature detection means (S21) for detecting a hot water supply / outflow temperature which is a temperature of hot water from the hot water supply heat exchanger (22);
A second temperature detecting means for detecting a hot water incoming water temperature which is a temperature of water supplied from the outside to the hot water supply heat exchanger (22);
Third temperature detecting means (S22) for detecting a hot water temperature which is the temperature of the hot water mixed by the mixing valve (31);
The hot water supply / outlet water temperature detected by the first temperature detection means (S21), the hot water supply water temperature detected by the second temperature detection means, and the hot water supply temperature detected by the third temperature detection means (S22). Based on this, the controller (10) controls the opening degree of the mixing valve (31) using feedforward control and feedback control so that the temperature of the hot water mixed by the mixing valve (31) becomes the hot water supply target temperature. ) And a hot water storage type water heater. In the hot water storage type hot water supply apparatus according to claim 1,
The control unit (10)
The hot water supply / outflow water temperature detected by the first temperature detection means (S21), the hot water supply water temperature detected by the second temperature detection means, the hot water supply target temperature, and the maximum opening of the mixing valve (31). A hot water storage type hot water supply apparatus, comprising: a mixing valve opening calculation unit (10a) for determining the opening of the mixing valve (31) when performing the feedforward control based on the degree. In the hot water storage type hot water supply device according to claim 2,
The control unit (10)
Command value correction for correcting the command value based on the opening of the mixing valve (31) obtained by the mixing valve opening calculating unit (10a) according to the opening characteristic with respect to the command value of the mixing valve (31) Part (10b),
The hot water storage type hot water supply apparatus characterized by outputting the command value corrected by the command value correction unit (10b) to the mixing valve (31). In the hot water storage type hot water supply device according to any one of claims 1 to 3,
An outside temperature detecting means (S3) for detecting the outside temperature is provided,
The hot water storage type hot water supply apparatus, wherein the second temperature detecting means estimates the hot water supply water temperature based on the outside air temperature detected by the outside air temperature detecting means (S3). In the hot water storage type hot water supply apparatus according to claim 1,
A mixing valve for obtaining a difference between the hot water supply target temperature and the hot water temperature detected by the third temperature detecting means (S22) and obtaining an opening of the mixing valve when performing the feedback control by PID control based on the difference. A hot water storage type hot water supply apparatus having an opening calculation unit (10a).

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