JP5721562B2 - Hot water supply apparatus and control method thereof - Google Patents

Description

  The present invention relates to a hot water supply apparatus and a control method thereof, and more particularly to a hot water supply apparatus having a circulation path.

  In general, with the circulation heating function that enables hot water to be immediately supplied from the hot water outlet of the hot water supply device and the instantaneous hot water supply of warm water, a circulation tank is provided to maintain the hot water supply tank at a high temperature. (For example, Patent Document 1 and Patent Document 2).

Patent Document 1 discloses that the hot water stored in the circulation tank is used up when hot water is supplied.
Patent Document 2 discloses that by providing a circulation tank and a circulation heating circuit, mixing of return hot water from the circulation tank, which is hot water having a low temperature, into the hot water supply tank is disclosed.

JP 2008-157471 A JP 2007-298226 A

  In the invention disclosed in Patent Document 1, when the circulation tank overflows due to prolonged circulation operation, the return hot water from the circulation tank is mixed into the hot water supply tank. Here, the hot water supply tank has a two-layer temperature gradient in which hot water is stored in the upper layer and water is stored in the lower layer. When returning hot water, which is hot water having a low temperature from the circulation tank, is mixed in such a hot water supply tank, there is a problem in that the temperature gradient layer in the hot water supply tank is disturbed to affect the hot water supply.

  In the invention disclosed in Patent Document 2, there is no risk that the return hot water from the circulation tank is mixed into the hot water supply tank, but even after the hot water stored in the hot water supply tank has been used up. The hot water for circulating the circulating heating circuit is still stored in the circulation tank. Compared with the case of Patent Document 1, the COP (Coefficient Of Performance) is lowered in that the hot water in the circulation tank cannot be used up, and there is a problem that the efficiency of the entire hot water supply device is lowered. It was.

  The present invention has been made in view of such circumstances, and the hot water in the circulation tank can be used without waste, and the return hot water from the circulation tank is prevented from being mixed into the hot water supply tank as much as possible. It is an object of the present invention to provide a hot water supply apparatus capable of performing the above and a control method thereof.

In order to solve the above problems, the hot water supply apparatus and the control method of the present invention employ the following means.
That is, the hot water supply apparatus according to the present invention has a heat pump, a plurality of hot water tanks for storing hot water heated by the heat pump, and a high temperature hot water pipe connected to the plurality of hot water tanks. A circulation path connected to the heat pump, and a mixing valve that mixes hot water led from the circulation path and high-temperature hot water led from the high-temperature hot water pipe to lead to the circulation path, The passage includes a circulation tank, circulation temperature detection means for detecting the temperature of the hot water in the circulation tank, and hot water on the high temperature side of the circulation tank to the mixing valve or the hot water piping by the circulation temperature detection means. A circulation path switching valve to be supplied, and a circulation path shut-off valve for linking hot water on the high temperature side of the circulation tank to the high temperature hot water pipe in conjunction with switching of the circulation path switching valve.

  Conventionally, the hot water in the circulation tank has been supplied only to the high temperature side or the low temperature side of the mixing valve. Therefore, the hot water mixed with the hot water from the hot water pipe and the hot water from the circulation tank at the mixing valve is circulated through the circulation path because the hot water temperature is lower than the hot water temperature in the hot water pipe. In the tank, hot water having a temperature lower than that of the hot water heated by the heat pump is always stored.

  Therefore, in the circulation path, the circulation temperature detection means circulates in conjunction with the switching of the circulation path switching valve and the circulation path switching valve that supplies hot water on the high temperature side of the circulation tank to the mixing valve low temperature side or hot water piping. A circulation path shut-off valve that joins hot water on the high temperature side of the tank to the high temperature hot water pipe is provided. Thus, depending on the hot water temperature in the circulation tank detected by the circulation temperature detection means, the high temperature side of the circulation tank directly from the high temperature side of the circulation tank to the low temperature side of the mixing valve, or from the high temperature side of the circulation tank through the high temperature hot water piping, The hot water from the circulation tank can be supplied to the side. Therefore, the hot water in the circulation tank can be used without waste.

  Furthermore, according to the hot water supply apparatus according to the present invention, the circulation path has a low temperature water pipe connected to the plurality of hot water supply tanks, and is connected to the heat pump. A communication valve for supplying hot water on the low temperature side of the circulation tank of the circulation path is provided in conjunction with the circulation path switching valve and the circulation path cutoff valve.

  The circulation path has a low-temperature water pipe connected to multiple hot water tanks and is connected to a heat pump. Hot water from the low-temperature side of the circulation tank is connected to the low-temperature water pipe, and the circulation path switching valve and the circulation path are shut off. In tandem with the valve, a communication valve that supplies low-temperature water piping was provided. As a result, even when the circulation tank is full of hot water, the return hot water is prevented from joining the low-temperature water piping from the low temperature side of the circulation tank, and the return hot water is circulated in the circulation path. Can do. Accordingly, since hot water is not mixed into the hot water supply tank, it is possible to prevent the temperature gradient layer in the hot water supply tank from being disturbed and affecting the hot water supply.

  Furthermore, according to the hot water supply apparatus according to the present invention, the communication valve is an automatic valve that is interlocked with the circulation path switching valve and the circulation path cutoff valve.

  As the communication valve, an automatic valve that automatically interlocks with the circulation path switching valve and the circulation path cutoff valve is used. Thereby, even when the circulation tank is filled with return hot water, hot water is supplied from the hot water supply tank, and the return hot water in the circulation tank can be accommodated in the circulation tank. Therefore, it is possible to prevent the temperature gradient layer in the hot water supply tank from being disturbed and affecting the hot water supply.

  Furthermore, according to the hot water supply apparatus according to the present invention, the communication valve is a manual valve and is normally closed.

  As the communication valve, a normally closed manual valve was used. Thereby, only hot water is supplied from the hot water supply tank, and the circulation tank can be dedicated to storing hot water for the return hot water circulating through the circulation. Therefore, it is possible to prevent the temperature gradient layer in the hot water supply tank from being disturbed and affecting the hot water supply.

  Furthermore, according to the hot water supply apparatus according to the present invention, the communication valve is a manual valve, and is always in a slightly open state.

As the communication valve, a manual valve that is always slightly open is used. Accordingly, even when the circulation tank is full, hot water is supplied from the hot water supply tank, and the return hot water in the circulation tank can be accommodated in the circulation tank. Therefore, it is possible to suppress the temperature gradient layer in the hot water supply tank from being disturbed and affecting the hot water supply.
The slightly open state means that even if the circulation operation is started without being stored in the circulation tank, the water in the circulation tank can be stored in the hot water together with the circulation operation. The degree of opening at which water stored in can be guided to the hot water tank.

  Furthermore, according to the hot water supply apparatus according to the present invention, the discharge side of the heat pump is provided with a heat pump side switching valve that switches the hot water heated by the heat pump to either the circulation path or the hot water tank. It is characterized by.

  A heat pump side switching valve for switching high temperature hot water heated by the heat pump to either the circulation path or the hot water supply tank is provided on the discharge side of the heat pump. Thereby, the hot water heated with the heat pump can be guide | induced to a circulation path, and a circulation tank can be heated. Therefore, hot water at a predetermined temperature can be immediately supplied when hot water is supplied.

  Further, according to the method for controlling a hot water supply apparatus according to the present invention, a heat pump, a plurality of hot water tanks for storing hot water heated by the heat pump, and a hot water pipe connected to the plurality of hot water tanks are provided. A circulation path that is connected to the heat pump, and a mixing valve that mixes the hot water led from the circulation path and the high-temperature hot water led from the high-temperature hot water pipe to lead to the circulation path, and The circulation path includes a circulation tank, circulation temperature detection means for detecting the hot water temperature in the circulation tank, and hot water on the high temperature side of the circulation tank by the circulation valve temperature detection means. A circulation path switching valve for supplying to the hot water pipe, and a circulation path shut-off valve for controlling the hot water on the high temperature side of the circulation tank to join the high temperature hot water pipe in conjunction with the switching of the circulation path switching valve. Of hot water supply equipment In the control method, when the temperature detecting means for circulation detects that the hot water temperature in the circulation tank is equal to or lower than a predetermined temperature, the circulation path switching valve is switched to the high temperature side of the circulation tank, and The circuit block valve is closed.

  The circulation path includes a circulation path switching valve for supplying hot water on the high temperature side of the circulation tank to the low temperature side of the mixing valve or high temperature hot water piping, and the circulation tank in conjunction with the switching of the circulation path switching valve. A circulation path shut-off valve for joining the hot water on the high temperature side to the hot water piping was provided. Thus, depending on the hot water temperature in the circulation tank detected by the circulation temperature detection means, the high temperature side of the circulation tank directly from the high temperature side of the circulation tank to the low temperature side of the mixing valve, or from the high temperature side of the circulation tank through the high temperature hot water piping, The hot water from the circulation tank can be supplied to the side. Therefore, the hot water in the circulation tank can be used without waste.

It is a schematic block diagram of the hot-water supply apparatus of this invention. It is the schematic which shows the flow of the hot water and tap water which concern on the hot water supply apparatus of this invention. It is the schematic which shows the flow of the hot water and tap water which concern on the hot water supply apparatus of this invention. It is the schematic which shows the flow of the hot water and tap water which concern on the hot water supply apparatus of this invention. It is the schematic which shows the flow of the hot water and tap water which concern on the hot water supply apparatus of this invention. It is the schematic which shows the flow of the hot water and tap water which concern on the hot water supply apparatus of this invention. It is a chart which shows the operation pattern of the valve and heat pump which are provided in the hot water supply device in the case of the night hot water storage operation concerning the hot water supply device of the present invention. It is a chart which shows the operation pattern of the valve and heat pump which are provided in the hot-water supply apparatus concerning a 1st embodiment. It is a graph which shows the operation pattern of the valve and heat pump which are provided in the hot water supply apparatus which concerns on 2nd Embodiment. It is a chart which shows the operation pattern of the valve and heat pump which are provided in the hot-water supply apparatus which concerns on 3rd Embodiment. It is a flowchart which shows the flow of the driving | running state shown in FIG. 10 is a flowchart showing a flow of the operation state shown in FIG. 9. It is a flowchart which shows the flow of the driving | running state shown in FIG.

[First embodiment]
FIG. 1 shows a schematic configuration diagram of a hot water supply apparatus of the present invention, and FIGS. 2 to 6 show flows of hot water and clean water according to the hot water supply apparatus of the present invention.
The hot water supply device 1 includes a plurality of (for example, nine) hot water supply tanks 3, a circulation tank 4, a CO ₂ heat pump (hereinafter referred to as “Peat pump”) 2, a mixing valve 5, a circulation cutoff valve 6, A circulation switching valve 7, a hot water supply circuit 8, and a circulation circuit (circulation path) 9 are provided.

  The hot water supply tank 3 has a bowl-shaped cylindrical shape. The hot water supply tank 3 stores hot water heated by the heat pump 2 to a high temperature. There are a plurality of hot water tanks 3, for example, 9 tanks 3 a, 3 b, 3 c, 3 d, 3 f, 3 g, 3 h, 3 i (in FIG. 1, only the hot water tank 3 a on the most downstream side and the hot water tank 3 i on the most upstream side are Is shown). The hot water tanks 3 are connected in series by a pipe 20.

  The most downstream hot water supply tank 3a is provided with a thermistor T1 at its lower part, and the uppermost stream hot water supply tank 3i is provided with a thermistor T9 at its upper part. Thereby, the hot water temperature stored in the lower part of the hot water supply tank 3a on the most downstream side or the hot water temperature stored in the upper part of the hot water supply tank 3i on the most upstream side is detected.

  The circulation tank 4 stores hot water or clean water (water) guided from a pipe 32 or a pipe 38 described later. The circulation tank 4 has the same shape and structure as the hot water supply tank 3 and is provided with about one tank.

  A thermistor (circulation temperature detection means) TC-U is provided above the circulation tank 4, and a thermistor (circulation temperature detection means) TC-L is provided below the circulation tank 4. Thereby, the hot water temperature currently stored in the upper part and the lower part in the circulation tank 4 is each detected.

The heat pump 2 uses CO ₂ as a refrigerant, and heats low-temperature hot water or clean water led to the heat pump 2 to derive high-temperature hot water. A pipe 11 is connected to the upstream side of the heat pump 2 to supply clean water or low temperature hot water to the heat pump 2. Connected to the downstream side of the heat pump 2 is a pipe 12 through which hot water heated by the heat pump 2 to a high temperature of, for example, 90 ° C. is guided.

  The mixing valve 5 mixes high-temperature hot water led from the pipe (high-temperature water side pipe) 23 of the hot water supply circuit 8 and low-temperature hot water led from the circulation circuit 9 to adjust to a predetermined hot water temperature. is there. The hot water adjusted to a predetermined hot water temperature by the mixing valve 5 is led out to the piping 31 constituting the circulation circuit 9.

  The circulation cutoff valve 6 is an electromagnetic valve that opens and closes when excited by the temperature detected by the thermistors TC-U and TC-L provided in the circulation tank 4. The opening / closing operation of the circulation shut-off valve 6 is interlocked with the switching operation of the circulation switching valve 7 described later. The circulation shutoff valve 6 is provided on a pipe 32 connecting the upper end of the circulation tank 4 and the pipe 23 of the hot water supply circuit 8.

  The circulation switching valve 7 is a three-way valve. The circulation switching valve 7 is connected with a pipe 33, a pipe 34 and a pipe 35 which will be described later. As described above, the circulation switching valve 7 is switched in conjunction with the opening / closing operation of the circulation cutoff valve 6 according to the temperature detected by the thermistors TC-U and TC-L provided in the circulation tank 4.

  A pipe 11 provided upstream of the heat pump 2 is connected to a first hot water storage switching valve 13. The first hot water storage switching valve 13 is a three-way valve, and in the other two directions, there are a pipe 36 that leads the low temperature hot water from the circulation tank 4 to the heat pump 2, and hot or cold water from the hot water supply circuit 8. To the heat pump 2 is connected.

  A pipe 12 provided downstream of the heat pump 2 is connected to a second hot water storage switching valve (heat pump side switching valve) 14. The second hot water storage switching valve 14 is a three-way valve, and in the other two directions, a pipe 37 for supplying hot water heated by the heat pump 2 to the circulation tank 4 and a hot water supply circuit for supplying the heated hot water. 8 is connected to the pipe 22 to be supplied to the pipe 8.

  The hot water supply circuit 8 includes a switching valve 15 to which a pipe 22 is connected, pipes 23 and 24 connected to the switching valve 15 that is a three-way valve, a plurality of hot water tanks 3, and a hot water tank 3 i on the most upstream side. And a pipe 25 connecting the pipe 23.

  The switching valve 15, which is a three-way valve, guides high-temperature hot water guided from the pipe 22 to the pipe 23 or the pipe 24 by switching. Usually, the switching valve 15 is switched to the pipe 23 side. The pipe 23 connects between the switching valve 15 and the mixing valve 5.

  A pipe 25 connecting the upper end of the hot water supply tank 3 i on the most upstream side joins the pipe 23. Furthermore, the pipe 32 of the circulation circuit 9 joins the pipe 23 between the mixing valve 5 and the downstream side where the pipe 25 joins.

  The pipe 24 connects the switching valve 15 and the lower end of the hot water supply tank 3a on the most downstream side. In addition, a pipe 21 connected to the first hot water storage switching valve 13 and a first water supply pipe 40 are connected to the lower end of the hot water supply tank 3a on the most downstream side.

  In the circulation circuit 9, a pipe 31 from which hot water whose temperature is adjusted is led out from the mixing valve 5, a circulation pump 17 that boosts the hot water led from the pipe 31, and hot water that has been boosted by the circulation pump 17 is led out. A pipe 42, a pipe 34 where the pipe 42 merges in the middle position, the circulation tank 4, a pipe 32 connecting the upper end of the circulation tank 4 and the pipe 23 of the hot water supply circuit 8, and a pipe 32 A circulation shutoff valve 6 provided on the top, a pipe 38 connected to the lower end of the circulation tank 4, a circulation switching valve 7 connected to a pipe 34 having the mixing valve 5 at one end, A pipe 33 connecting the circulation switching valve 7 and the pipe 32 and a pipe 35 connected to the other end of the circulation switching valve 7 which is a three-way valve are provided.

  The pipe 31 is provided with a hot water supply port (not shown) for supplying hot water having a predetermined hot water temperature passing through the mixing valve 5 to the outside. The remaining hot water in the pipe 31 that has not been supplied from the hot water supply port to the outside of the hot water supply device 1 is guided to the circulation pump 17.

  A pipe 42 is connected to the downstream side of the circulation pump 17, and hot water pressurized by the circulation pump 17 is led out. Here, the hot water boosted by the circulation pump 17 circulates in the circulation circuit 9 to prevent the temperature of the circulation circuit 9 from decreasing.

  The pipe 42 through which the hot water boosted by the circulation pump 17 is led joins the pipe 34. One end of the pipe 34 is connected to the mixing valve 5, and the other end is connected to the circulation switching valve 7.

  The pipe 32 connects the upper end of the circulation tank 4 and the pipe 23 of the hot water supply circuit 8. The piping 32 is provided with a circulation shut-off valve 6 at a midway position thereof. A pipe 37 that guides hot water from the heat pump 2 joins the pipe 32 on the upstream side of the circulation shut-off valve 6. Furthermore, a pipe 33 connected to the circulation switching valve 7 is joined to the pipe 32 on the upstream side of the junction where the pipe 37 joins.

  Connected to the circulation switching valve 7 are a pipe 33, a pipe 34 connecting the mixing valve 5, and a pipe 35. The second clean water supply pipe 41 and the pipe 39 are joined and connected to the other end of the pipe 35. A pipe 39 that joins the pipe 35 and the second clean water supply pipe 41 joins a pipe 38 that is connected to the lower end of the circulation tank 4.

  A pipe 39 connected to the lower end of the circulation tank 4 is connected to a pipe 39, a pipe 36 connected to the heat pump 2, and a pipe (low temperature water pipe) 43.

  The pipe 43 connects the circulation circuit 9 and the hot water supply circuit 8. The pipe 43 joins the first clean water supply circuit 40 connected to the lower end of the hot water supply tank 3a on the most downstream side, and the tank communication valve 18 is provided at a midway position thereof. The tank communication valve 18 is an automatic communication valve, and its opening degree is controlled in conjunction with the circulation switching valve 7 and the circulation cutoff valve 6. As described above, the opening degree of the tank communication valve 18 is controlled in conjunction with the circulation switching valve 7 and the circulation cutoff valve 6, so that hot water from the pipe 38 or the pipe 39 passes through the pipe 43 and the first water supply pipe. 40.

Next, the flow of hot water and clean water flowing through the hot water supply apparatus 1 having the configuration shown in FIG. 1 and the operating conditions of the valves and the heat pump will be described with reference to FIGS.
2 to 6 show the flow of hot water and clean water flowing through the hot water supply apparatus 1, and FIGS. 7 and 8 show the operation patterns of the valves and the heat pump.
Here, the hot water supply switching valves 13 and 14 shown in the charts of FIGS. 7 and 8 are the hot water supply switching valves 13 and 14 switched to the piping 21 and 22 side of the hot water supply circuit 8 side in FIGS. 2 to 6. The circulation side means that the hot water storage switching valves 13 and 14 are switched to the piping 36 and 37 side on the circulation circuit 9 side. The circulation side of the circulation switching valve 7 means switching to the pipe 33 side, and the water supply side of the circulation switching valve 7 means switching to the pipe 35 side. Further, in FIG. 7, the ◯ mark indicates the switching side, and the X mark indicates the non-switching side. Furthermore, a-mark indicates that there is no change or no detection.

  The high temperature shown in the hot water supply tank 3 and the circulation tank 4 in FIG. 7 is equal to or higher than a set temperature (about 65 ° C. to 90 ° C.) minus 15 ° C., and is about 50 ° C. to 75 ° C. or lower. Yes. Further, the intermediate temperature is equal to or higher than the temperature obtained by subtracting 20 ° C. from the set temperature, is approximately 45 ° C. to 70 ° C. or lower, and is higher than a low temperature described later. Further, the low temperature indicates a temperature equal to or lower than a temperature obtained by adding 20 ° C. to the water temperature (temperature of the clean water supplied from the first clean water supply pipe 40 or the second clean water supply pipe 41). Here, the set temperature is further set separately for the hot water supply tank 3 and the circulation tank 4. In the hot water supply tank 3, for example, the hot water supply temperature is 90 ° C., and in the circulation tank 4, for example, 65 ° C. ing.

First, the hot water flow at night will be described.
When the hot water supply apparatus 1 of the present embodiment is operated at night to perform only hot water storage (1 in FIG. 7), the heat pump 2 is activated and the hot water storage switching valves 13 and 14 are connected to the hot water supply circuit 8 side, that is, the pipes 21 and 22. Switch to the side. Further, the opening of the mixing valve 5 is set to the minimum opening state.

  Here, the minimum opening state of the mixing valve 5 means that the temperature of the hot water supplied from the hot water supply port becomes too high to prevent the burner from being burned. It means the opening that can mix the low temperature hot water from.

Next, a case where hot water is stored in the hot water supply tank 3 during night operation (2 in FIG. 7) will be described.
When the thermistor T1 provided in the hot water supply tank 3a detects that the hot water temperature in the hot water supply tank 3a closest to the water supply pipe has not reached a high temperature (indicated by x high in 2 in FIG. 7) Then, the hot water storage switching valves 13 and 14 are switched to the pipes 21 and 22 side, and the heat pump 2 is operated with the mixing valve 5 in the minimum opening state.

  The hot water that has become hot due to the operation of the heat pump 2 is led out to the pipe 22 through the hot water storage switching valve 14 as indicated by the arrow I in FIG. The hot water led out to the pipe 22 is guided to the three-way valve 15 and supplied to the pipe 23. The hot water supplied to the pipe 23 during the hot water storage operation is guided to the pipe 25.

  The hot water led to the pipe 25 is led from the upper end of the hot water supply tank 3i on the most upstream side into the hot water supply tank 3i. As a result, the hot water having a lowered temperature (hot water not hot) stored in the hot water tank 3i is guided from the lower end of the hot water tank 3i to the hot water tank 3h (not shown) through the pipe 20. Similarly, the hot water in each hot water supply tank 3 is guided in turn from the upstream hot water supply tank 3 to the downstream hot water supply tank 3, and finally the hot water is discharged from the lower end of the most downstream hot water supply tank 3a. It is led out to the pipe 21.

  The hot water led out to the pipe 21 is led to the heat pump 2 through the hot water storage switching valve 13 and heated. By repeating this, hot water is stored in the hot water supply tank 3 of the hot water supply circuit 8.

  Along with the progress of hot water storage, when the thermistor T9 provided in the upper part of the hot water supply tank 3i on the most upstream side to the thermistor T1 provided in the lower part of the hot water supply tank 3a each detect a high temperature state. The hot water storage switching valves 13 and 14 are switched to the pipes 36 and 37 to switch to hot water storage in the circulation tank 4 (3 in FIG. 7).

  With the progress of hot water storage in the circulation tank 4, the thermistor TC-U and the thermistor TC-L installed in the upper part and the lower part of the circulation tank 4 successively detect the high temperature state. With the high temperature detection of the thermistor TC-L, the hot water storage switching valves 13 and 14 are switched to the pipes 21 and 22 side, and the heat pump 2 stops operation (4 in FIG. 7). In this way, the nighttime hot water storage operation is stopped.

  Next, a circulation operation (53 in FIG. 8) in which hot water is circulated in the circulation circuit 9 of the hot water supply apparatus 1 after hot water is stored in the hot water supply tank 3 by night operation as described above will be described. At this time, when the thermistor TC-U provided in the upper part of the circulation tank 4 detects a high temperature, the circulation switching valve 7 is switched to the pipe 35 side, and the circulation cutoff valve 6 is opened. The communication valve 18 is closed, and the mixing valve 5 is in the temperature control state.

  Since the circulation shut-off valve 6 is in the open state, the hot water in the circulation tank 4 is led out from the upper end of the circulation tank 4 to the pipe 32 and joins to the pipe 23 as indicated by the arrow III in FIG. . The hot water joined to the pipe 23 is mixed with the hot water led from the pipe 32 in the mixing valve 5 and led out to the pipe 31.

  The hot water led out to the pipe 31 is led to the circulation pump 17, boosted by the circulation pump 17, and led out to the pipe 42. The hot water led out to the pipe 42 joins the pipe 34. A part of the hot water joined to the pipe 34 is guided to the mixing valve 5, and the rest is guided to the circulation switching valve 7.

  Here, since the circulation switching valve 7 is switched to the pipe 35 side, the hot water led to the circulation switching valve 7 is led out to the pipe 35. The hot water led out to the pipe 35 is led into the circulation tank 4 from the lower end of the circulation tank 4 through the pipe 39 and the pipe 38. Here, since the tank communication valve 18 provided on the pipe 43 is in a closed state, hot water is not guided to the pipe 43.

  The hot water stored in the circulation tank 4 is led out from the upper end of the circulation tank 4 to the pipe 32 by the hot water introduced into the circulation tank 4 from the lower end of the circulation tank 4. By repeating this, circulation operation is performed.

Next, the flow of raising the temperature of the hot water in the circulation tank 4 during the circulation operation (heating the circulation tank 4) will be described.
A case where the thermistor TC-U detects that the hot water temperature in the upper part of the circulation tank 4 has decreased from a high temperature (54 in FIG. 8) will be described. At this time, the circulation switching valve 7 is switched to the pipe 33 side, and the circulation cutoff valve 6 is closed. Further, the tank communication valve 18 is closed, and the mixing valve 5 is in the minimum opening state. Furthermore, the heat pump 2 enters the operating state, and the hot water storage switching valves 13 and 14 are switched to the pipes 36 and 37 side.

  Hot water is led to the mixing valve 5 from the pipe 42 of the circulation circuit 9 and is led to the pipe 31 as indicated by an arrow IV in FIG. The hot water led out to the pipe 31 is led to the circulation pump 17, boosted by the circulation pump 17, and led out to the pipe 42. The hot water led out to the pipe 42 joins the pipe 34. Most of the hot water joined to the pipe 34 is led to the mixing valve 5 because the circulation shutoff valve 6 and the tank communication valve 18 are closed and the circulation switching valves 13 and 14 are switched to the circulation tank 4 side. .

  Further, the hot water heated by the heat pump 2 is led out to the pipe 37 through the hot water storage switching valve 14. The hot water led out to the pipe 37 joins the pipe 32 and is led into the circulation tank 4 from the upper end of the circulation tank 4 as indicated by an arrow II in FIG.

  The hot water stored in the circulation tank 4 is heated by the hot water indicated by the arrow II in FIG. 4 and the hot water indicated by the arrow IV in FIG. Is led out to the pipe 38 from the lower end thereof. Here, since the tank communication valve 18 provided in the pipe 43 merging with the pipe 38 is in a closed state, the hot water led out to the pipe 38 is led to the heat pump 2 through the pipe 36. In this way, the circulation tank 4 is heated together with the circulation operation.

  Next, the case (55 in FIG. 8) of stopping the heating of the circulation tank 4 performed along with the circulation operation will be described. When the thermistor TC-U provided in the upper part of the circulation tank 4 detects a high temperature, the circulation switching valve 7 is switched to the pipe 35 side, and the circulation cutoff valve 6 is opened. Further, the tank communication valve 18 is closed, and the mixing valve 5 is in the temperature control state. Further, the operation of the heat pump 2 is stopped, and the hot water storage switching valves 13 and 14 are on the pipes 36 and 37 side.

  When the circulation switching valve 7 is switched to the pipe 35 side, the circulation shut-off valve 6 is opened, and the tank communication valve 18 is closed, as shown by the arrow III in FIG. Hot water in the circulation tank 4 is led out to the pipe 32. The hot water led out to the pipe 32 joins the pipe 23 and is led to the mixing valve 35.

  In the mixing valve 5, hot water from the pipe 42 of the circulation circuit 9 and hot water from the pipe 23 are guided and mixed. The hot water mixed by the mixing valve 5 is led out to the pipe 31 as indicated by an arrow III in FIG. The hot water led out to the pipe 31 is led to the circulation pump 17, boosted by the circulation pump 17, and led out to the pipe 42. The hot water led out to the pipe 42 joins the pipe 34. A part of the hot water joined to the pipe 34 is guided to the mixing valve 5, and the rest is guided to the circulation switching valve 7.

  Here, since the circulation switching valve 7 is switched to the pipe 35 side, a part of the hot water joined to the pipe 34 is led out to the pipe 35 through the circulation switching valve 7. The hot water led out to the pipe 35 is led into the circulation tank 4 from the lower end of the circulation tank 4 through the pipe 39 and the pipe 38. Here, since the tank communication valve 18 provided on the pipe 43 is in a closed state, hot water is not guided to the pipe 43.

  In addition, since the operation of the heat pump 2 is stopped, hot water is not led to the upper end of the circulation tank 4 from the circulation switching valve 14 through the pipe 37. As described above, hot water is led from the upper end of the circulation tank 4 to the pipe 32 by being led from the pipe 38 into the circulation tank 4. In this way, the circulation operation is performed, but the heating of the circulation tank 4 is stopped.

  When the thermistor T9 provided in the uppermost stream hot water supply tank 3i detects that the hot water in the uppermost stream hot water supply tank 3i has not reached a high temperature during the circulation operation of 53 in FIG. 8 (in FIG. 8) No. 56) will be described. At this time, the circulation switching valve 7 is set to the pipe 35 side, the circulation cutoff valve 6 is opened, the tank communication valve 18 is closed, and the mixing valve 5 is in the temperature control state or the minimum opening state. Moreover, the heat pump 2 operates and the hot water storage switching valves 13 and 14 are switched to the pipes 21 and 22 side.

  When the heat pump 2 is operated and the hot water storage switching valves 13 and 14 are switched to the pipes 21 and 22 side, the hot water heated by the heat pump 2 and having a high temperature is switched to the hot water switching as shown by the arrow I in FIG. It is led to the pipe 22 through the valve 14. The hot water led out to the pipe 22 is guided to the three-way valve 15 and supplied to the pipe 23. The hot water supplied to the pipe 23 is not directed to the mixing valve 5 because the tank communication valve 18 is closed, and is led to the pipe 25.

  The hot water led to the pipe 25 is led from the upper end of the hot water supply tank 3i on the most upstream side into the hot water supply tank 3i. As a result, the hot water stored in the hot water supply tank 3i is guided from the lower end in the hot water supply tank 3i to the hot water supply tank 3h via the pipe 20. Similarly, hot water is led sequentially from the upstream hot water supply tank 3 to the downstream hot water supply tank 3, so that the hot water supply tank 3 a finally passes from the lower end of the most downstream hot water supply tank 3 a to the pipe 21. Hot water that is stored in the hot water and is not hot is extracted. The hot water led out to the pipe 21 is led to the heat pump 2 through the hot water storage switching valve 13 and heated.

  On the other hand, the hot water stored in the circulation tank 4 is led to the pipe 32 from the upper end of the circulation tank 4 as indicated by the arrow III in FIG. 2 because the circulation cutoff valve 6 is opened. To join the pipe 23. The hot water joined to the pipe 23 is led to the mixing valve 5 and led to the pipe 31.

  The hot water led out to the pipe 31 is led to the circulation pump 17, boosted by the circulation pump 17, and led out to the pipe 42. The hot water led out to the pipe 42 joins the pipe 34. A part of the hot water joined to the pipe 34 is guided to the mixing valve 5, and the rest is guided to the circulation switching valve 7.

  Here, since the circulation switching valve 7 is switched to the pipe 35 side, the hot water led to the circulation switching valve 7 is led out to the pipe 35. The hot water led out to the pipe 35 is led into the circulation tank 4 from the lower end of the circulation tank 4 through the pipe 39 and the pipe 38. Here, since the tank communication valve 18 provided on the pipe 43 is in a closed state, hot water is not guided to the pipe 43.

With the hot water introduced from the lower end of the circulation tank 4, the hot water stored in the circulation tank 4 is led out from the upper end of the circulation tank 4 to the pipe 32.
As described above, the circulation operation and the warming of the hot water supply tank 3 are performed by repeating the flow indicated by the arrows I and III in FIG.

  Next, the case where the warming of the hot water supply tank 3 performed along with the circulation operation is stopped (57 in FIG. 8) will be described. A thermistor T9 provided in the hot water supply tank 3i on the most upstream side, or a thermistor (not shown) of the hot water supply tank 3 disposed closer to the first water supply pipe 40 detects a high temperature. As a result, the operation of the heat pump 2 is stopped. The circulation switching valve 7 is switched to the pipe 35 side, the circulation cutoff valve 6 is open, the tank communication valve 18 is closed, the mixing valve 5 is in the temperature control state or the minimum opening state, and the hot water storage switching valves 13 and 14 are piping. 21 and 22 side. This is the same as 56 in FIG.

  When the operation of the heat pump 2 is stopped, hot water is not led to the hot water supply tank 3. Thereby, the heating of the hot water supply tank 3 is stopped.

  On the other hand, the hot water stored in the circulation tank 4 is led out from the upper end of the circulation tank 4 to the pipe 32 as indicated by the arrow III in FIG. 2 because the circulation cutoff valve 6 is opened. To join the pipe 23. The hot water joined to the pipe 23 is led to the mixing valve 5 and led to the pipe 31.

  The hot water led out to the pipe 31 is led to the circulation pump 17, boosted by the circulation pump 17, and led out to the pipe 42. The hot water led out to the pipe 42 joins the pipe 34. A part of the hot water joined to the pipe 34 is guided to the mixing valve 5, and the rest is guided to the circulation switching valve 7.

  Here, since the circulation switching valve 7 is switched to the pipe 35 side, the hot water led to the circulation switching valve 7 is led out to the pipe 35. The hot water led out to the pipe 35 is led into the circulation tank 4 from the lower end of the circulation tank 4 through the pipe 39 and the pipe 38. Here, since the tank communication valve 18 provided on the pipe 43 is in a closed state, hot water is not guided to the pipe 43.

The hot water stored in the circulation tank 4 is led out from the upper end of the circulation tank 4 to the pipe 32 by the hot water introduced into the circulation tank 4 from the lower end of the circulation tank 4.
In this way, the heating operation of the hot water supply tank 3 can be stopped and the circulation operation can be performed.

Next, the flow in the case of supplying hot water outside the hot water supply apparatus 1 will be described.
When the hot water supply is started, as indicated by 61 in FIG. 8, the circulation switching valve 7 is switched to the pipe 35 side, the circulation cutoff valve 6 is opened, the tank communication valve 18 is closed, and the mixing valve 5 is heated. Control state. At this time, the thermistors T9 and TC-U provided in the uppermost part of the hot water supply tank 3i and the circulation tank 4 on the most upstream side detect high temperatures.

  By starting the hot water supply, as shown by the arrow VI in FIG. 3, the clean water is supplied from the first clean water supply pipe 40 to the lower end of the hot water supply tank 3a on the most downstream side. The hot water stored in the hot water supply tank 3a from the upper end of the hot water supply tank 3a by the hot water led into the hot water supply tank 3a on the most downstream side from the first hot water supply pipe 40 passes through the pipe 20 It is led to an upstream hot water supply tank 3b (not shown). Similarly, hot water is sequentially guided from the downstream hot water supply tank 3 to the upstream hot water supply tank 3, and the hot water stored in the uppermost hot water supply tank 3i passes above the hot water supply tank 3i. It is led out from the end to the pipe 25.

  The hot water led out to the pipe 25 joins the pipe 23 and is led to the mixing valve 5 together with hot water indicated by an arrow VII in FIG. Here, since the circulation switching valve 7 is switched to the pipe 35 side, the hot water led from the pipe 23 and the hot water from the pipe 42 are supplied to the mixing valve 5.

  When hot water is supplied, clean water is supplied from the second clean water supply pipe 41 to the pipe 39 and the pipe 35. Since the circulation switching valve 7 is switched to the pipe 35 side, the clean water supplied to the pipe 35 is guided to the mixing valve 5 as indicated by the arrow VII in FIG.

  Further, the clean water from the second clean water supply pipe 41 led to the pipe 39 is led into the circulation tank 4 from the lower end of the circulation tank 4 through the pipe 38. In addition, since the tank communication valve 18 provided on the piping 43 where the piping 38 merges is in a closed state, clean water is not guided to the piping 43.

  The hot water stored in the circulation tank 4 by the clean water introduced into the circulation tank 4 from the lower end of the circulation tank 4 is led out to the pipe 32 from the upper end of the circulation tank 4. Here, since the circulation shut-off valve 6 provided on the pipe 32 is in an open state, the high-temperature hot water led out to the pipe 32 joins the pipe 23. In this manner, the hot water mixed from the hot water led from the hot water supply tank 3i and the circulation tank 4 and the hot water led from the pipe 34 are led to the mixing valve 5.

  The opening degree of the mixing valve 5 is controlled according to the set temperature supplied from the hot water supply port, that is, the amount of hot water mixed with the clean water introduced from the pipe 34 to the mixing valve 5 is controlled. . As a result, hot water having a predetermined hot water temperature is led out from the mixing valve 5 to the pipe 31. The hot water having a predetermined hot temperature led out to the pipe 31 is supplied from the hot water outlet provided in the pipe 31 to the outside of the hot water supply apparatus 1.

  Next, during hot water supply, the hot water in the uppermost stream hot water supply tank 3i detected by the thermistor T9 is hot, but if the hot water in the upper part of the circulation tank 4 does not reach high temperature, it is provided at the upper part of the circulation tank 4. When the detected thermistor TC-U is detected (62 in FIG. 8), the circulation switching valve 7 is switched to the pipe 33 side, the circulation cutoff valve 6 is closed, the tank communication valve 18 is opened, hot water storage While the thermistors TC-L provided at the switching valves 13 and 14 on the piping 36 and 37 side and under the circulation tank 4 do not detect the low temperature, the heat pump 2 is in an operating state. The mixing valve 5 is in a temperature control state.

  The hot water storage switching valves 13 and 14 are switched to the pipes 36 and 37 side, and the heat pump 2 is operated while the thermistor TC-L provided at the lower part of the circulation tank 4 does not detect the low temperature, whereby II of FIG. As indicated by the arrows, the hot water heated by the heat pump 2 is guided from the hot water storage switching valve 14 to the upper end of the circulation tank 4 through the pipe 37. The hot water guided to the circulation tank 4 is guided from the upper end of the circulation tank 4 into the circulation tank 4.

  High-temperature hot water is led into the circulation tank 4 from the upper end of the circulation tank 4, and hot water stored in the circulation tank 4 is led out from the lower end of the circulation tank 4 to the pipe 38. Hot water that is not at a high temperature led to the pipe 38 is led from the pipe 36 to the heat pump 2 via the hot water storage switching valve 13.

  On the other hand, clean water is guided from the second clean water supply pipe 41 to the pipe 35 and the pipe 39. At this time, since the circulation switching valve 7 is switched to the pipe 33 side, the clean water is supplied from the lower end of the circulation tank 4 through the pipe 39 through the pipe 38 as indicated by the arrow VIII in FIG. Led in.

  When hot water is introduced into the circulation tank 4 from the lower end of the circulation tank 4, the hot water stored in the circulation tank 4 is transferred to the upper end of the circulation tank 4 as indicated by an arrow IX in FIG. 5. To the pipe 32. Here, since the circulation shut-off valve 6 provided on the pipe 32 is in the closed state and the circulation switching valve 7 is switched to the pipe 33 side, the hot water led out to the pipe 32 passes through the circulation switching valve 7. It is led out to the pipe 34.

  The hot water led out to the pipe 34 is mixed with the hot water led from the pipe 42 and led to the mixing valve 5. Furthermore, as shown by the arrow VI in FIG. 5, hot water stored in the hot water supply tank 3 is led to the mixing valve 5 from the pipe 23. Therefore, hot water from the pipe 23 and hot water mixed with clean water guided by the pipe 34 are mixed in the mixing valve 5 to reach a predetermined hot water temperature and led to the pipe 31. Hot water of a predetermined hot temperature led out to the pipe 31 is supplied from the hot water supply port provided in the pipe 31 to the outside of the hot water supply device 1. In this way, the circulation tank 4 is heated together with the hot water supply.

As described above, the hot water supply apparatus 1 according to the present embodiment has the following operational effects.
In the circulation circuit (circulation path) 9, hot water in the upper part (high temperature side) of the circulation tank 4 is mixed with the mixing valve 5 or piping (high temperature hot water piping) by thermistors (temperature detection means for circulation) TC-U, TC-L. ) The circulation switching valve 7 to be supplied to 23 and the circulation cutoff valve 6 for joining the hot water in the upper part of the circulation tank 4 to the pipe 23 in conjunction with the switching of the circulation switching valve 7 are provided. Thereby, according to the hot water temperature in the circulation tank 4 detected by the thermistors TC-U and TC-L, the hot water in the circulation tank 4 is supplied from the upper part of the circulation tank 4 to the pipe 33, the circulation switching valve 7, and the pipe 34. Can be supplied directly to the mixing valve 5, or can be supplied from the upper part of the circulation tank 4 to the mixing valve 5 after being joined to the piping 23 via the piping 32 and the circulation shutoff valve 6. Therefore, the hot water in the circulation tank 4 can be used up.

  A tank communication valve (communication valve) 18 is provided on a pipe (low temperature water pipe) 43 that leads hot water from the lower part (low temperature side) of the circulation tank 4 to the supply circuit 8 from the circulation circuit 9. The tank communication valve 18 is linked to the circulation switching valve 7 and the circulation cutoff valve 6. Thus, even when the circulation tank 4 is full, the return hot water from the circulation tank 4 is prevented from joining from the lower part of the circulation tank 4 to the pipe 43, and the return hot water is supplied to the circulation circuit 9. Can be circulated inside. Therefore, since the return hot water from the circulation tank 4 is not mixed into the hot water supply tank 3, it is possible to prevent the temperature gradient layer in the hot water supply tank 3 from being disturbed and affecting the hot water supply.

  As the tank communication valve 18, an automatic valve that automatically interlocks with the circulation switching valve 7 and the circulation cutoff valve 6 is used. Thus, even when the circulation tank 4 is full, hot water from the hot water supply tank 3 is supplied to the hot water supply, and the return hot water from the circulation tank 4 is circulated in the circulation circuit 9 for circulation. It can be accommodated in the tank 4. Therefore, it is possible to prevent the temperature gradient layer in the hot water supply tank 3 from being disturbed and affecting the hot water supply.

  A hot water storage switching valve (heat pump side switching valve) 14 for switching to supply hot water heated by the heat pump 2 to either the circulation tank 4 of the circulation circuit 9 or the hot water supply tank 3 is provided on the discharge side of the heat pump 2. It was decided to be provided in the pipe 12. Thereby, the hot water heated by the heat pump 2 can be guided to the circulation circuit 9 and the circulation tank 4 can be heated. Therefore, when hot water is supplied, hot water having a predetermined temperature can be immediately supplied.

  In the present embodiment, the three-way valve 15 and the pipe 24 are described. However, the present invention is not limited to this, and the three-way valve 15 and the pipe 24 may be omitted.

[First Modification of First Embodiment]
In the present embodiment, it is described that the circulation operation (see 53 in FIG. 8) is performed without storing hot water in the circulation tank 4 during night operation. However, as a first modification, the circulation tank 4 is used together with the circulation operation. It is also good to store hot water.

  When hot water is stored in the circulation tank 4 together with the circulation operation (51 in FIG. 8), the water is already stored in the circulation tank 4. Therefore, when the thermistor TC-L provided in the lower part of the circulation tank 4 detects the low temperature, the circulation switching valve 7 is switched to the pipe 33 side, the circulation cutoff valve 6 is closed, and the mixing valve 5 is The temperature control state is set, and the tank communication valve 18 is opened.

  Since the tank communication valve 18 is opened and the circulation shutoff valve 6 is closed, low temperature clean water in the circulation tank 4 is piped from the lower end of the circulation tank 4 as indicated by an arrow X in FIG. The first water supply pipe 40 is led through 38 and 43. The low temperature clean water led to the first clean water supply pipe 40 is led into the hot water supply tank 3a from the lower end of the hot water supply tank 3a on the most downstream side.

  The hot water stored in the hot water supply tank 3a from the upper end of the hot water supply tank 3a by the low temperature hot water introduced into the hot water supply tank 3a on the most downstream side passes through the pipe 20 and the upstream hot water supply tank 3b. (Not shown), and similarly, the water is supplied in turn from the hot water supply tank 3 on the downstream side to the hot water supply tank 3 on the upstream side. In this way, the hot water stored in the hot water supply tank 3 is led out to the pipe 25 from the upper end of the hot water supply tank 3i on the most upstream side. The hot water led out to the pipe 25 joins the pipe 23 and is led to the mixing valve 5.

  In the mixing valve 5, hot water (or water) that is not high temperature led from the pipe 34 of the circulation circuit 9 and hot water that is led from the pipe 23 are mixed. The hot water mixed by the mixing valve 5 is guided to the circulation pump 17 through the pipe 31. The hot water led to the circulation pump 17 is boosted by the circulation pump 17 and led to the pipe 42. The hot water led out to the pipe 42 joins the pipe 34, a part thereof is led to the mixing valve 5, and the rest is led to the circulation switching valve 7.

  The hot water guided to the circulation switching valve 7 is led to the piping 33 and guided into the circulation tank 4 from the upper end of the circulation tank 4 because the circulation switching valve 7 is switched to the piping 33 side. In this manner, the circulating operation can be performed, and the medium temperature hot water can be stored in the circulation tank 4.

  When the hot water temperature becomes an intermediate temperature from the upper part in the circulation tank 4 by 51 in FIG. 8 and the hot water temperature in the lower part in the circulation tank 4 is no longer low (52 in FIG. 8), that is, circulation. When the thermistor TC-L provided in the lower part of the tank 4 detects the temperature not reaching the low temperature, and the thermistor TC-U provided in the upper part of the circulation tank 4 detects the medium temperature Then, the circulation switching valve 7 is switched to the pipe 35 side, the circulation cutoff valve 6 is opened, the tank communication valve 18 is closed, and the heat pump 2 is in operation. The mixing valve 5 is in a temperature control state.

  Since the tank communication valve 18 is closed and the circulation shutoff valve 6 is opened, the medium temperature hot water in the circulation tank 4 flows from the upper end of the circulation tank 4 as indicated by the arrow III in FIG. It merges into the pipe 23 through the pipe 32 and the circulation shutoff valve 6. Hot water joined to the pipe 23 is guided to the mixing valve 5.

  In the mixing valve 5, hot water (or water) that is not high-temperature led from the pipe 34 and hot water led from the pipe 23 are mixed. The hot water mixed by the mixing valve 5 is guided to the circulation pump 17 through the pipe 31. The hot water led to the circulation pump 17 is boosted by the circulation pump 17 and led to the pipe 42. The hot water led out to the pipe 42 joins the pipe 34, a part thereof is led to the mixing valve 5, and the rest is led to the circulation switching valve 7.

  Further, since the circulation switching valve 7 is switched to the pipe 35 side, a part of the hot water that has been pressurized by the circulation pump 17 and led from the pipe 42 to the pipe 34 is led out to the pipe 29 via the pipe 35. The hot water led out to the pipe 39 joins the pipe 38 via the pipe 39. Therefore, the hot water led to the pipe 38 is led into the circulation tank 4 from the lower end of the circulation tank 4.

Further, the hot water heated by the heat pump 2 is led to the pipe 37 through the hot water storage switching valve 14. The hot water led out to the pipe 37 joins the pipe 32 and is led into the circulation tank 4 from the upper end of the circulation tank 4 as indicated by an arrow II in FIG.
As described above, the circulating operation can be performed and hot water can be stored in the circulation tank 4.

[Modification 2 of the first embodiment]
Further, as a modified example of 62 in FIG. 8 of the present embodiment, as in modified example 2, no additional hot water is stored in the circulation tank 4 in a time zone in which the hot water supply operation is mainly performed before the night hot water storage operation time. It is good as a thing.
In this case (63 in FIG. 8), by detecting that the thermistor TC-U provided in the upper part of the circulation tank 4 is not at a high temperature, the circulation switching valve is similar to 62 in FIG. 7 is switched to the pipe 33 side, the circulation cutoff valve 6 is closed, the mixing valve 5 is in the temperature control state, and the tank communication valve 18 is in the open state. However, unlike the case of 62 in FIG. 8, the heat pump 2 stops its operation.

  Since the operation of the heat pump 2 is stopped, high temperature hot water is not supplied from the heat pump 2 to the circulation tank 4 via the pipe 37 as indicated by the arrow II in FIG. Therefore, no additional hot water storage is performed in the circulation tank 4.

The flow is the same as that indicated by arrows VIII and IX in FIG. 5 described in the case of 62 in FIG. 8 except that no additional hot water is stored in the circulation tank 4.
In this manner, hot water having a predetermined hot water temperature is supplied from the hot water supply port provided in the pipe 31 to the outside of the hot water supply device 1, but no additional hot water is stored in the circulation tank 4.

[Modification 3 of the first embodiment]
Furthermore, as a third modification, a flow meter 16 may be provided on the pipe 23 to control the open / close state of the circulation shut-off valve 6 at the start of hot water supply indicated by 61 in FIG.
When the flow meter 16 detects the flow of hot water and the switch is turned on (64 in FIG. 8), the circulation switching valve 7 is switched to the pipe 35 side as in 61 in FIG. The communication valve 18 is closed and the mixing valve 5 is temperature controlled. At this time, the thermistors T9 and TC-U provided in the uppermost part of the hot water supply tank 3i and the circulation tank 4 on the most upstream side detect high temperatures. In addition, unlike the case of 61 in FIG. 8, the circulation shut-off valve 6 is closed.

  The flow meter 16 is provided on the pipe 23 between the downstream side where the pipe 25 connected to the hot water tank 3 is joined and the upstream side where the pipe 32 is joined.

  Similarly to the case described in 61 in FIG. 8, as indicated by an arrow VI in FIG. 3, hot water supply is started, and hot water is guided from the hot water supply tank 3 to the pipe 23 through the pipe 25. The switch of the flow meter 16 is turned on.

When the switch of the flow meter 16 is turned on, the circulation cutoff valve 6 is closed. Therefore, hot water from the circulation tank 4 is not led out to the pipe 32. That is, hot water in the circulation tank 4 does not join the pipe 23 via the pipe 32.
The flow is the same as that indicated by arrows VI and VII in FIG. 3 described in the case of 61 in FIG. 8 except that the hot water in the circulation tank 4 does not join the pipe 23.

  Further, when it is detected that hot water has stopped flowing and the switch of the flow meter 16 is turned off (65 in FIG. 8), the circulation switching valve 7 is connected to the pipe 35, similarly to 61 in FIG. The tank communication valve 18 is closed, the circulation shutoff valve 6 is opened, and the mixing valve 5 is temperature controlled. At this time, the thermistors T9 and TC-U provided in the uppermost part of the hot water supply tank 3i and the circulation tank 4 on the most upstream side detect high temperatures. In addition, unlike the case of 64 in FIG. 8, the circulation shut-off valve 6 is opened.

  When the hot water passing through the pipe 23 is not detected by the flow meter 16, the switch of the flow meter 16 is turned off. When the switch of the flow meter 16 is turned off, the circulation cutoff valve 6 is opened. Therefore, hot water from the circulation tank 4 joins the pipe 23 via the pipe 32.

  In addition, each operation of 1 in FIG. 7, 2 in FIG. 7, 4 in FIG. 7 and 51 in FIG. 8 to 65 in FIG. 8 is combined as shown in the flowchart of FIG. May be used.

[Second Embodiment]
The hot water supply apparatus of this embodiment is different from the first embodiment in that the tank communication valve is manually operated and is normally closed, and the others are the same. Therefore, about the same structure, the flow of hot water and clean water, the same code | symbol is attached | subjected and the description is abbreviate | omitted.
Here, the tank communication valve (communication valve) 18 provided on the pipe (low temperature water pipe) 43 is manually operated and is normally closed.

The flow during nighttime hot water storage is the same for 1 in FIG. 7, 2 in FIG. 7 and 4 in FIG. 7 described in the first embodiment, but hot water is stored in the circulation tank 4 during nighttime hot water storage. The point is different.
Here, the flow in the case of performing night operation and storing hot water in the circulation tank 4 (3 in FIG. 7) will be described.
When the thermistor TC-L provided in the lower part of the circulation tank 4 detects that the hot water temperature in the circulation tank 4 has not reached a high temperature, the hot water storage switching valves (heat pump side switching valves) 13 and 14 are It switches to the piping 36 and 37 side, the heat pump 2 will be in an operation state, and the mixing valve 5 will be in the minimum opening degree state.

  When the heat pump 2 is operated, hot hot water is led to the pipe 37 through the hot water storage switching valve 14 as indicated by an arrow II in FIG. The hot water led out to the pipe 37 is led into the circulation tank 4 from the upper end of the circulation tank 4.

  The hot water stored in the circulation tank 4 is led out from the lower end of the circulation tank 4 to the pipe 38 by the hot water introduced into the circulation tank 4 from the upper end of the circulation tank 4 to store the hot water. It is guided to the heat pump 2 through the switching valve 13. By repeating this, hot water is stored in the circulation tank 4.

  Next, a circulation operation (13 in FIG. 9) in which hot water is circulated in the circulation circuit 9 of the hot water supply apparatus 1 after the hot water supply tank 3 and the circulation tank 4 are stored by night operation as described above will be described. In this case, the circulation operation is performed similarly to 53 in FIG. 8 and FIG. 2 described in the first embodiment.

Next, the case where the hot water in the circulation tank 4 is heated to a high temperature during the circulation operation (heating of the circulation tank 4) (14 in FIG. 9) will be described.
When it is detected that the thermistor TC-U provided in the upper part of the circulation tank 4 has dropped to an intermediate temperature, the hot water storage switching valves 13 and 14 are switched to the pipes 36 and 37 side, and the circulation switching valve 7 is connected to the pipe 33 side. The circulation shutoff valve 6 is closed (the tank communication valve 18 is fixed in the closed state), the mixing valve 5 is in the minimum opening state, and the heat pump 2 is in the operating state. Except that the operation state of each valve 5, 6, 7, 13, 14, (valve 18) and the heat pump 2 is changed by the thermistor TC-U detecting the intermediate temperature, the one in FIG. 8 described in the first embodiment. 54 and FIG. 4, the circulation tank 4 is heated together with the circulation operation.

  Next, the case (15 in FIG. 9) of stopping the heating of the circulation tank 4 performed together with the circulation operation will be described. In this case, similarly to 55 in FIG. 8 and FIG. 2 described in the first embodiment, the heating of the circulation tank 4 performed together with the circulation operation is finished.

  Next, when the thermistor T1 provided in the most downstream side hot water supply tank 3a detects that the hot water in the most downstream side hot water supply tank 3a does not reach a high temperature during the circulation operation 13 in FIG. 9 in FIG. 9), and the thermistor T9 detects that the hot water in the hot water supply tank 3i heated by 16 in FIG. 9 is high (17 in FIG. 9). These are also the same as 56 and 57 in FIG. 8 described in the first embodiment and FIG.

Next, the flow in the case of supplying hot water outside the hot water supply apparatus 1 will be described.
When hot water supply is started (21 in FIG. 9), hot water is supplied in the same manner as 61 in FIG. 8 and FIG. 3 described in the first embodiment.

  Next, during hot water supply, the hot water in the uppermost hot water supply tank 3i detected by the thermistor T9 is hot, but if the hot water in the upper part of the circulation tank 4 does not reach high temperature, it is provided in the circulation tank 4. When the detected thermistor TC-U is detected (22 in FIG. 9), the circulation switching valve 7 is switched to the pipe 33 side, the circulation cutoff valve 6 is closed, the tank communication valve 18 is closed, and the heat pump 2 is In the operating state, the hot water storage switching valves 13 and 14 are switched to the pipes 36 and 37 side, and the mixing valve 5 is brought into the temperature control state. The operating states of the valves 5, 6, 7, 13, 14 and the heat pump 2 are the same as 62 in FIG. 8 described in the first embodiment except that the tank communication valve 18 is closed.

  The flow of hot water is also substantially the same as in FIG. 5 described in the first embodiment, but in this embodiment, since the tank communication valve 18 is fixed in a closed state, piping is started from the lower end of the circulation tank 4. The hot water which is not led to the high temperature led to 38 is not led to the pipe 43, but is led from the pipe 36 joining the pipe 38 to the heat pump 2 through the hot water storage switching valve 13. For this reason, the hot water stored in the circulation tank 4 and not reaching the high temperature is led to the heat pump 2 without being mixed into the hot water supply tank 3 and heated. Therefore, it is possible to prevent the temperature gradient layer in the hot water supply tank 3 from being disturbed and affecting the hot water supply.

As described above, the hot water supply apparatus 1 according to the present embodiment has the following operational effects.
As the tank communication valve (communication valve) 18, a normally closed manual valve is used. As a result, only hot water is supplied from the hot water supply tank 3, and the circulation tank 4 can be dedicated to storing hot water for return hot water that circulates in the circulation circuit (circulation path) 9.

[Modification 1 of the second embodiment]
In the present embodiment as well, as in the case of the first embodiment, as a first modification, the additional hot water may not be stored in the circulation tank 4 immediately before the night hot water storage operation.
This case (23 in FIG. 9) is the same as 63 in FIG. 8 described in the first embodiment. That is, the operation of the heat pump 2 is stopped from the state 22 in FIG. The operation states of the respective valves 5, 6, 7, 13, 14, and 18 and the detection states of the thermistors TC-U and T9 are the same as 22 in FIG. Moreover, it is the same as that of 63 in FIG. 8 demonstrated in 1st Embodiment, and FIG. 5 except the tank communication valve 18 being a closed state.

[Modification 2 of the second embodiment]
As in the case of the first embodiment, as a second modification, a flow meter 16 is provided on the pipe 23 to control the open / close state of the circulation shut-off valve 6 at the start of hot water supply indicated by 21 in FIG. You may do it.
This case (24 in FIG. 9 and 25 in FIG. 9) is the same as 64 in FIG. 8, 65 in FIG. 8, and FIG. 3 described in the first embodiment.

  The above-described operations 1 to 4 in FIG. 7 and 4 in FIG. 7 and 13 in FIG. 9 to 25 in FIG. 9 may be used in combination as shown in the flowchart of FIG.

[Third Embodiment]
The hot water supply apparatus of the present embodiment is different from the first embodiment in that the tank communication valve is manually operated and is always kept in a slightly open state, and the others are the same. Therefore, about the same structure, the flow of hot water and clean water, the same code | symbol is attached | subjected and the description is abbreviate | omitted.
Here, the tank communication valve (communication valve) 18 provided on the pipe (low temperature water pipe) 43 is manually operated and is always in a slightly opened state.

  Note that the slightly open state is not stored in the circulation tank 4, and even when the circulation operation is started in a state where clean water (water) is stored in the circulation tank 4, The degree of opening that leads the hot water stored in the circulation tank 4 to the hot water supply tank 3 to such an extent that the hot water in the circulation tank 4 can be stored as hot water.

Circulation operation (31 in FIG. 10 to 37 in FIG. 10) is basically the same as 51 in FIG. 8 to 57 in FIG. 8 described in the first embodiment, but the tank communication valve 18 is fine. The difference is that it is open.
Here, by combining with the operation of the heat pump 2, even if the tank communication valve 18 is in a slightly opened state, the hot water led out to the pipe 38 is mixed into the hot water supply tank 3 due to the pressure loss relationship in the connected pipe. Can be suppressed.

  Thus, in the case of this embodiment, the driving | operation substantially the same as 1st Embodiment is attained. Therefore, the second embodiment in which the tank communication valve 18 is in the closed state and the present embodiment in the slightly open state are composed of the same parts, and can be used by switching every season or according to the expected operating condition at the time. .

As described above, the hot water supply apparatus 1 according to the present embodiment has the following operational effects.
As the tank communication valve (communication valve) 18, a manual valve that is always slightly open is used. Thereby, even when the circulation tank 4 is full of water, the circulation tank 4 can be dedicated to storing hot water of return hot water that circulates in the circulation circuit (circulation path) 9. Therefore, it is possible to suppress the temperature gradient layer in the hot water supply tank 3 from being disturbed and affecting the hot water supply.

[Modification 1 of the third embodiment]
In this embodiment as well, as in the case of the first embodiment, as a first modification, the additional hot water may not be stored in the circulation tank 4 immediately before the hot water storage operation at night (43 in FIG. 10).

[Modification 2 of the third embodiment]
Furthermore, as in the case of the first embodiment as a second modification, a flow meter 16 is provided on the pipe 23 to control the open / close state of the circulation shut-off valve 6 at the start of hot water supply indicated by 41 in FIG. (44 in FIG. 10 and 45 in FIG. 10).

  The above-mentioned operations 1 in FIG. 7, 2, 2 in FIG. 7, 4 in FIG. 7, and 31 in FIG. 10 to 45 in FIG. 10 are used in combination as shown in the flowchart of FIG. May be.

DESCRIPTION OF SYMBOLS 1 Hot-water supply apparatus 2 Heat pump 3 Hot-water supply tank 4 Circulation tank 5 Mixing valve 7 Circulation path cutoff valve 8 Circulation path switching valve 9 Circulation path (circulation circuit)
23 Hot water piping (piping)
TC-L, TC-U Circulating temperature detection means (Thermistor)

Claims (7)

A heat pump,
A plurality of hot water tanks for storing hot water heated by the heat pump;
A circulation path having high temperature hot water pipes connected to the plurality of hot water tanks and connected to the heat pump;
A mixing valve that mixes hot water led from the circulation path and high-temperature hot water led from the previous high-temperature hot water pipe and leads to the circulation path, and
The circuit is
A circulation tank,
Circulation temperature detection means for detecting the temperature of hot water in the circulation tank;
A circulation path switching valve for supplying hot water on the high temperature side of the circulation tank to the mixing valve or the high temperature hot water piping by the temperature detection means for circulation;
A hot water supply apparatus comprising: a circulation path shut-off valve that joins hot water on a high temperature side of the circulation tank to the high temperature hot water pipe in conjunction with switching of the circulation path switching valve. The circulation path has a low-temperature water pipe connected to a plurality of the hot water tanks and is connected to the heat pump,
2. The low temperature water pipe is provided with a communication valve that supplies hot water on a low temperature side of the circulation tank of the circulation path in conjunction with the circulation path switching valve and the circulation path cutoff valve. The hot water supply device described in 1.   The hot water supply apparatus according to claim 2, wherein the communication valve is an automatic valve that is interlocked with the circulation path switching valve and the circulation path cutoff valve.   The hot water supply apparatus according to claim 2, wherein the communication valve is a manual valve and is normally closed.   The hot water supply apparatus according to claim 2, wherein the communication valve is a manual valve and is always in a slightly opened state.   6. The heat pump side switching valve for switching the hot water heated by the heat pump to either the circulation path or the hot water supply tank is provided on the discharge side of the heat pump. The hot-water supply apparatus in any one. A heat pump,
A plurality of hot water tanks for storing hot water heated by the heat pump;
A circulation path having a high-temperature hot water pipe connected to the plurality of hot water tanks and connected to the heat pump;
A mixing valve that mixes hot water led from the circulation path and high-temperature hot water led from the high-temperature hot water pipe and leads to the circulation path,
The circuit is
A circulation tank,
Circulation temperature detection means for detecting the temperature of hot water in the circulation tank;
A circulation path switching valve for supplying hot water on the high temperature side of the circulation tank to the mixing valve or the high temperature hot water piping by the temperature detection means for circulation;
In conjunction with the switching of the circulation path switching valve, a control method for a hot water supply apparatus comprising a circulation path cutoff valve for controlling the hot water on the high temperature side of the circulation tank to join the high temperature hot water pipe,
When the circulating temperature detecting means detects that the hot water temperature in the circulating tank is below a predetermined temperature, the circulating path switching valve is switched to the high temperature side of the circulating tank and the circulating path shut-off valve is closed. A method for controlling a hot water supply apparatus, characterized by:

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