JP5854854B2 - Hot water system - Google Patents

Description

  The present invention relates to a hot water supply system including a hot water circulation circuit for enabling immediate hot water supply.

  In a hot water supply system where hot water produced by a water heater is stored in a hot water storage tank and the hot water can be discharged from a faucet, shower head, or other hot water terminal when necessary, for example, when the faucet is opened, In order to be able to supply hot water, a hot water circulation circuit is provided between a hot water supply device and a hot water storage tank and a hot water supply terminal, and a hot water supply terminal is installed and installed in this hot water circulation circuit (for example, (See Patent Documents 1 and 2).

  In addition, by installing a dedicated sealed circulation tank that is independent from the hot water tank in the hot water circulation circuit, the hot water circulating in the hot water circulation circuit and the hot water stored in the hot water tank are mixed. Those which are configured not to be performed are also disclosed in Patent Documents 1 and 2 above.

JP 2007-298226 A JP 2008-157471 A

  As described above, in the case of a hot water supply system incorporating a hot water circulation circuit having a closed circulation tank, the amount of hot water supply varies depending on the performance of the water heater, depending on the outside air temperature, the water supply temperature, the boiling temperature, etc. Therefore, during the recirculation hot water reheating operation, the ratio between the recirculation hot water amount and the reheating flow rate by the water heater is not constant. For this reason, the amount of hot water stored in the circulation tank is not constant, and hot water boiled by the hot water heater and hot water circulating in the hot water circulation circuit are mixed in the circulation tank, and the hot water storage temperature tends to become unstable. There was a problem.

  The present invention has been made in view of such circumstances, and hot water having different temperatures in the circulation tank is obtained by substantially separating the circuit during the heating operation of warm water circulating in the hot water circulation circuit. An object of the present invention is to provide a hot water supply system capable of stabilizing the hot water storage temperature so as not to mix.

In order to solve the above problems, the hot water supply system of the present invention employs the following means.
That is, a hot water supply system according to the present invention includes a hot water heater that heats low temperature water to produce high temperature water, a high temperature water pipe connected to the hot water heater via a high temperature water pipe and a low temperature water pipe, and the high temperature water produced by the hot water heater. A hot water storage tank for storing water is connected to the high temperature water pipe and the low temperature water pipe via a switching valve, and at least one hot water supply terminal connected to a hot water discharge pipe from the hot water storage tank is provided. A hot water circulation circuit, the hot water circulation circuit having a pair of first circulation tank and second circulation tank connected in series in the circuit and connected to the high temperature water pipe, and on the upstream side The bottom of the first circulation tank and the low temperature water pipe are connected via the switching valve, and the bottom of the second circulation tank and the hot water circulation circuit on the downstream side are upstream of the first circulation tank. Characterized in that in the switching valve and through the bypass circuit are connected.

  According to the present invention, a hot water supply device, a hot water storage tank for storing hot water produced by the hot water supply device, and a hot water circulation circuit provided with one or more hot water supply terminals are provided. It has a pair of first circulation tank and second circulation tank connected in series in the circuit, and the bottom of the first circulation tank on the upstream side and the low-temperature water piping are connected via a switching valve. And the bottom of the second circulation tank on the downstream side and the hot water circulation circuit are connected to each other on the upstream side of the first circulation tank via a switching valve and a bypass circuit, so that the first and second circulation tanks When the hot water temperature in the hot water circulation circuit including the temperature drops, the hot water circulation circuit can be circulated to the hot water circulation circuit by bypassing the first circulation tank by switching the hot water circulation circuit to the bypass circuit side with the switching valve. The first circulation tank is separated from the hot water circulation circuit side, the changeover valve is switched, and the hot water in the first circulation tank is circulated and boiled to the water heater by connecting to the water heater via the high temperature water pipe and the low temperature water pipe. You can drive more. Also, once the boiling of the warm water in the first circulation tank is completed, the boiling operation is temporarily terminated, and the warm water circulation circuit is switched from the bypass circuit side to the first circulation tank side by a switching valve, thereby the first circulation tank. The hot water inside can be moved to the second circulation tank side, and when the hot water having a low temperature flowing into the first circulation tank from the hot water circulation circuit side is filled with the movement of the high temperature water, By switching the circulation circuit to the bypass circuit side by the switching valve and separating the first circulation tank from the hot water circulation circuit side, and circulating the hot water in the first circulation tank to the hot water heater in the same manner as described above, Both hot water in the first circulation tank and the second circulation tank can be boiled up to high temperature water. Therefore, the hot water in the hot water circulation circuit can always be kept above the set temperature to maintain the immediate hot water supply function, and the hot water boiling in the hot water heater and the hot water circulation tank circulating in the hot water circulation circuit can be maintained. It is possible to prevent the generation of medium temperature water that cannot be used on the load side and cannot be heated by a hot water heater.

  In the hot water supply system according to the present invention, in the hot water supply system described above, the bypass circuit is connected between the hot water circulation circuit and the second circulation tank via the switching valve including a three-way valve. Features.

  According to the present invention, since the bypass circuit is connected between the hot water circulation circuit and the second circulation tank via the switching valve composed of a three-way valve, in order to cope with a decrease in the hot water temperature on the hot water circulation circuit side. This circuit can be configured simply by adding a three-way switching valve and a bypass circuit. Therefore, a complicated configuration and control for avoiding mixing of the hot water circulating in the hot water circulation circuit and the high-temperature water boiled by the hot water heater are not required, and the configuration can be simplified and the cost can be reduced.

  Furthermore, the hot water supply system according to the present invention is the hot water supply system according to any one of the above, wherein the first circulating tank and the second circulating tank are connected to the connecting pipe that connects the tops of each other with the high-temperature water pipe. The hot water circulation circuit is connected to each bottom part.

  According to the present invention, the first circulation tank and the second circulation tank are connected to the connecting pipe connecting the tops of each other with the hot water piping, and the hot water circulation circuit is connected to each bottom, When the temperature of the hot water in the hot water circulation circuit decreases, the hot water in the first circulation tank is heated up and moved to the second circulation tank via a connecting pipe connected between the tops. When the hot water from the side of the hot water circulation circuit that has flowed into the inside is re-boiling, on the second circulation tank side, the hot water circulation that has flowed from the bypass circuit connected to the bottom is directly connected to the bottom The circuit can be short-circuited to hold the hot water stored in the second circulation tank so as not to circulate. Therefore, when the boiling of hot water in the first circulation tank and the second circulation tank is completed, a hot water layer having a low temperature does not remain between the first circulation tank and the second circulation tank, and the hot water storage temperature is reduced. It is possible to further stabilize and improve both circulation performance and hot water supply performance.

  Furthermore, in the hot water supply system of the present invention, in any one of the hot water supply systems described above, the first circulation tank and the second circulation tank are connected to connect a top portion of the first circulation tank and a bottom portion of the second circulation tank. The hot water pipe is connected to a pipe, and the hot water circulation circuit is connected to a bottom part of the first circulation tank and a top part of the second circulation tank.

  According to the present invention, the first circulation tank and the second circulation tank are connected to the connecting pipe that connects the top of the first circulation tank and the bottom of the second circulation tank, and the high-temperature water pipe is connected to the first circulation tank. Since the warm water circulation circuit is connected to the bottom and the top of the second circulation tank, when the temperature of the warm water in the warm water circulation circuit decreases, the warm water in the first circulation tank is boiled and the hot water is fed to the first circulation tank. When the hot water from the hot water circulation circuit side that has flowed into the first circulation tank is re-boiling after moving from the top to the bottom of the second circulation tank via the connecting pipe, the bottom of the second circulation tank side The warm water can be circulated while maintaining the temperature layer with the high-temperature water by allowing the warm water to flow in from the bypass circuit connected to, and flowing the warm water to the warm water circulation circuit connected to the top. Therefore, it is possible to prevent high temperature water boiling in the hot water heater and hot water circulating in the hot water circulation circuit from being mixed, and to stabilize the hot water storage temperature and improve both circulation performance and hot water supply performance. it can.

  Furthermore, in the hot water supply system of the present invention, in any one of the hot water supply systems described above, a first temperature sensor and a second temperature sensor are provided in the vicinity of the top and bottom of the first circulation tank, respectively. When the temperature of the hot water circulating in the circuit decreases and the first and second temperature sensors detect a temperature lower than a set temperature, the hot water circulation circuit is switched to the bypass circuit side by the switching valve, and the first The hot water is circulated by bypassing the circulation tank, and the first circulation tank is connected to the water heater via the high temperature water pipe and the low temperature water pipe by switching the switching valve. When the first and second temperature sensors detect a high temperature that is equal to or higher than a preset temperature, the additional heating operation is stopped and the hot water circulation circuit is stopped. Is switched from the bypass circuit side to the first circulation tank side by the switching valve to move the hot water from the first circulation tank to the second circulation tank, and the hot water circulation circuit in the first circulation tank. When the first and second temperature sensors detect the temperature below the set temperature again, the hot water circulation circuit is switched to the bypass circuit side by the switching valve, and the first circulation tank is turned on. The hot water is circulated by bypass, and the first circulation tank is connected to the hot water supply device via the high temperature water pipe and the low temperature water pipe by switching the switching valve, and the hot water in the first circulation tank is boiled. When the first and second temperature sensors detect again a high temperature equal to or higher than the set temperature, the additional heating operation is stopped and the hot water circulation circuit is turned off. By switching from the bypass circuit side to the first circulation tank side by a valve, the hot water in the hot water circulation circuit including the first circulation tank and the second circulation tank is maintained at a set temperature or higher. It is characterized by that.

  According to the present invention, the temperature of the hot water in the hot water circulation circuit is lowered, and the first temperature sensor and the second temperature sensor provided in the vicinity of the top and the bottom of the first circulation tank have detected temperatures below the set temperature. When the hot water circulation circuit is switched to the bypass circuit side by the switching valve, the hot water is circulated by bypassing the first circulation tank, and hot water is supplied to the first circulation tank via the hot water piping and the cold water piping by switching the switching valve. Connected to the machine, can be operated by boiling the hot water in the first circulation tank, and when the first and second temperature sensors detect a high temperature above the set temperature, the heating operation is stopped and the hot water circulation circuit Is switched from the bypass circuit side to the first circulation tank side by the switching valve, so that the hot water in the first circulation tank can be moved to the second circulation tank. Along with the movement of the high-temperature water, when the first and second temperature sensors detect low-temperature hot water flowing into the first circulation tank from the hot-water circulation circuit side, the hot-water circulation circuit is again bypassed by the switching valve. In the same manner as above, the first circulation tank is bypassed and hot water is circulated, and the first circulation tank is connected to the water heater via the high-temperature water pipe and the low-temperature water pipe, and again in the first circulation tank. When hot water is increased and the first and second temperature sensors detect a high temperature that is equal to or higher than the set temperature, boiling operation is stopped and the hot water circulation circuit is switched from the bypass circuit side to the first circulation tank side by the switching valve. By switching, the hot water temperature in the hot water circulation circuit including the first circulation tank and the second circulation tank can be maintained at a set temperature or higher. Accordingly, the hot water in the hot water circulation circuit can always be kept at the set temperature or higher by simple control by simply switching the switching valve based on the detected temperatures of the two temperature sensors, and an immediate hot water supply function can be maintained. At the same time, the mixing of hot water boiling in the hot water heater and the hot water circulating in the hot water circulation circuit is prevented, the hot water is stabilized and the hot water is heated up in the hot water heater that cannot be used on the load side. The generation of the medium temperature water that cannot be done can be prevented.

  According to the present invention, when the hot water temperature in the hot water circulation circuit including the first and second circulation tanks is reduced, the hot water circulation circuit is switched to the bypass circuit side by the switching valve, thereby bypassing the first circulation tank and warm water. Hot water can be circulated through the circulation circuit. During this time, the first circulation tank is separated from the hot water circulation circuit side, and the switching valve is switched and connected to the hot water supply device via the high temperature water pipe and the low temperature water pipe. The hot water in the circulation tank can be circulated to the water heater to increase the boiling operation. Also, once the boiling of the warm water in the first circulation tank is completed, the boiling operation is temporarily terminated, and the warm water circulation circuit is switched from the bypass circuit side to the first circulation tank side by a switching valve, thereby the first circulation tank. The hot water inside can be moved to the second circulation tank side, and when the hot water having a low temperature flowing into the first circulation tank from the hot water circulation circuit side is filled with the movement of the high temperature water, By switching the circulation circuit to the bypass circuit side by the switching valve and separating the first circulation tank from the hot water circulation circuit side, and circulating the hot water in the first circulation tank to the hot water heater in the same manner as described above, Since the hot water in the first circulation tank and the second circulation tank can both be boiled up to high temperature water, the hot water in the hot water circulation circuit is always kept above the set temperature to maintain an immediate hot water supply function. In addition, it prevents hot water from boiling in the hot water heater and hot water circulating in the hot water circulation circuit from mixing in the tank, stabilizes the hot water temperature, and boiles it in medium hot water and hot water heaters that cannot be used on the load side. The generation of medium temperature water that cannot be raised can be prevented.

1 is a schematic configuration diagram of a hot water supply system according to a first embodiment of the present invention. It is an operation state explanatory view at the time of the composition of the 1st and 2nd circulation tank part of the warm water circulation circuit of the hot-water supply system shown in Drawing 1, and its warm water boiling operation. FIG. 3 is an operation state explanatory diagram of a next step during the hot water boiling operation shown in FIG. 2. It is an operation state explanatory view of the next step at the time of warm water boiling operation shown in FIG. It is an operation state explanatory view of the next step at the time of warm water boiling operation shown in FIG. It is an operation state explanatory view at the time of the composition of the 1st and 2nd circulation tank part of the warm water circulation circuit concerning the 2nd embodiment of the present invention, and its warm water boiling operation. It is an operation state explanatory view of the next step at the time of warm water boiling increase operation shown in FIG. It is an operation state explanatory view of the next step at the time of warm water boiling operation shown in FIG. It is an operation state explanatory view of the next step at the time of warm water boiling increase operation shown in FIG.

Embodiments according to the present invention will be described below with reference to the drawings.
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 5.
FIG. 1 shows a schematic configuration diagram of a hot water supply system according to the first embodiment of the present invention.
A hot water supply system 1 is connected to a hot water supply device 2 that heats low temperature water to produce high temperature water, and a high temperature water pipe 3 and a low temperature water pipe 4 connected to the hot water supply device 2. A hot water storage tank 5 comprising a plurality of hot water storage tanks 5A, 5B,... 5N for storing hot water is connected to the high temperature water pipe 3 and the low temperature water pipe 4 via three-way switching valves (switching valves) 6, 7, and A hot water circulation circuit 10 provided with at least one or more hot water supply terminals 9 connected to the hot water discharge pipe 8 from the tank 5 is provided.

  The water heater 2 heats the low-temperature water circulated through the low-temperature water pipe 4 and the circulation pump 11 to produce high-temperature water at a predetermined temperature, and can be configured by a known heat pump, boiler, or the like. In this embodiment, a refrigeration cycle including a compressor, a refrigerant / water heat exchanger 12, an expansion valve, and an air heat exchanger is provided, and the refrigerant / water heat exchanger 12 exchanges heat between high-temperature and high-pressure refrigerant and low-temperature water. It is assumed that a heat pump that generates high-temperature water is used.

  The hot water storage tank 5 is composed of a plurality of sealed hot water storage tanks 5A, 5B,... 5N connected in series with each other, and the hot water pipe 3 from the water heater 2 is at the top of the uppermost hot water storage tank 5N. The hot water storage tank 5N and the hot water storage tank 5A are sequentially connected from the most upstream hot water storage tank 5N to the hot water storage tank 5B. Further, a low temperature water pipe 4 and a water pipe 13 connected to the hot water heater 2 through a circulation pump 11 are connected to the bottom of the most downstream hot water storage tank 5A. The plurality of hot water storage tanks 5A, 5B,... 5N are connected in series by sequentially connecting the top of the hot water storage tank 5A and the bottom of the hot water storage tank 5B, and the top of the hot water storage tank 5B and the bottom of the hot water storage tank 5B. It is connected to the.

  The hot water circulation circuit 10 includes at least one hot water supply terminal 9 such as a faucet or a shower head, and when the hot water supply terminal 9 is operated, hot water at a required temperature is discharged immediately. . The hot water circulation circuit 10 is connected to the hot water storage tank 5N, which is the uppermost stream of the hot water storage tank 5, via a hot water discharge pipe 8, and includes a circulation pump 14 for circulating hot water. The hot water circulation circuit 10 mixes hot water discharged from the hot water storage tank 5 via the hot water discharge pipe 8 and hot water in the hot water circulation circuit 10 and supplies hot water from the hot water supply terminal 9 as hot water having a predetermined temperature. However, since it is not directly related to the present invention, a description thereof is omitted here.

  In the hot water circulation circuit 10, a pair of hermetic first circulation tanks 15 and second circulation tanks 16 are connected in series with each other. The pair of first circulation tank 15 and second circulation tank 16 is connected to the hot water circulation circuit 10 at the bottom of the first circulation tank 15 and the tops of the first circulation tank 15 and the second circulation tank 16 are connected to each other. Since the hot water circulation circuit 10 is connected to the bottom of the second circulation tank 16 by the pipe 17, the first circulation tank 14 and the second circulation tank 15 are sequentially provided in the warm water circulation circuit 10 in the hot water circulation direction. It is configured to be connected and arranged in series.

  The hot water circulation circuit 10 is branched from the high temperature water pipe 3 through a three-way switching valve (switching valve) 6 to a connecting pipe 17 connecting the tops of the first circulation tank 15 and the second circulation tank 16. By connecting the high-temperature water pipe 3A, the high-temperature water pipe 3 from the water heater 2 is connected via the three-way switching valve (switching valve) 6 and the bottom of the first circulation tank 15 is connected to the low-temperature water pipe 4A. And it is connected to the low temperature water piping 4 to the hot water heater 2 by being connected to the low temperature water piping 4 through a three-way switching valve (switching valve) 7.

  Further, the hot water circulation circuit 10 bypasses the first circulation tank 15 between the upstream position of the first circulation tank 15 provided in the circuit 10 and the bottom of the second circulation tank 16. A bypass circuit 18 capable of circulating the circulating hot water to the second circulation tank 16 is connected via a three-way switching valve (switching valve) 19. A first temperature sensor 20 and a second temperature sensor 21 that detect the temperature of hot water stored in the first circulation tank 15 are provided near the top and the bottom of the first circulation tank 15, respectively.

Next, the operation of the hot water supply system 1 according to this embodiment will be described.
The hot water storage operation for storing high-temperature water at a predetermined temperature in the hot water storage tank 5 is performed by operating the water heater 2 using inexpensive late-night power. In this case, the clean water supplied to the hot water storage tank 5 through the water supply pipe 13 is circulated to the water heater 2 through the low temperature water pipe 4 and the circulation pump 11, and this low temperature water is circulated by the refrigerant / water heat exchanger 12 of the heat pump. High-temperature water is produced by heat exchange with a high-temperature and high-pressure refrigerant. This hot water is introduced into the uppermost hot water storage tank 5N of the hot water storage tank 5 composed of a plurality of tank groups via the hot water pipe 3 and the three-way switching valve 6, and the hot water storage tank 5B on the downstream side sequentially from the uppermost hot water storage tank 5N. The required amount of hot water is stored in the hot water storage tank 5A.

  When a temperature sensor (not shown) provided in the most downstream hot water storage tank 5A detects that hot water has been stored in the hot water storage tank 5A, the hot water storage operation to the hot water storage tank 5 is terminated. When the hot water storage operation for the hot water storage tank 5 is completed, the three-way switching valves (switching valves) 6 and 7 are switched to the high temperature water pipe 3A and the low temperature water pipe 4A side, and the pair of the first circulation tank 15 and the second circulation tank 16 are switched. The same hot water storage operation is performed. In this manner, a required amount of hot water can be stored in the plurality of hot water storage tanks 5, the first circulation tank 15, and the second circulation tank 16 using midnight power at night.

  The hot water stored in the first circulation tank 15 and the second circulation tank 16 is adjusted to hot water at a predetermined temperature while being circulated in the hot water circulation circuit 10 by the operation of the circulation pump 14, and the hot water is required for a time zone. , The hot water is supplied from the hot water supply terminal 9 connected to the hot water circulation circuit 10. When operating the hot water supply terminal 9 during this hot water supply, it is necessary to always circulate the hot water adjusted to the predetermined temperature in the hot water circulation circuit 10 in order to immediately discharge the hot water at the predetermined temperature. . When hot water in the hot water circulation circuit 10 is consumed by hot water supply from the hot water supply terminal 9, an amount of high temperature corresponding to the amount of hot water consumed from the hot water storage tank 5N of the hot water storage tank 5 through the hot water discharge pipe 8 is obtained. Water is discharged, and an amount of clean water corresponding to that amount is supplied to the hot water storage tank 5A and the hot water circulation circuit 10.

  On the other hand, the temperature of the hot water circulating in the hot water circulation circuit 10 including the first circulation tank 15 and the second circulation tank 16 is inevitably lowered due to heat radiation or the like with the passage of time. The temperature of this hot water is detected by the first temperature sensor 20 and the second temperature sensor 21 provided near the top and the bottom of the first circulation tank 15, and when the temperature falls below the set temperature, the hot water is supplied immediately. It becomes impossible to respond. For this reason, it is necessary to increase the temperature of the hot water in the hot water circulation circuit 10 for operation.

This boiling increase operation will be described in detail with reference to FIGS.
As shown in FIG. 2, the hot water in the hot water circulation circuit 10 flows from the bottom of the first circulation tank 15 and flows from the top to the top of the second circulation tank 16 through the connecting pipe 17 as indicated by a thick arrow. Then, by flowing out of the second circulation tank 16, the hot water circulation circuit 10 is circulated. In this state, when the temperature of the hot water in the first circulation tank 15 decreases and becomes lower than the set temperature as indicated by the oblique lines, the three-way switching is performed when the first temperature sensor 20 and the second temperature sensor 21 detect the temperature. The valve (switching valve) 19 is switched from A → B to A → C, and the three-way switching valves (switching valves) 6 and 7 are switched to the high temperature water pipe 3A and the low temperature water pipe 4A side. Driven.

  Therefore, the hot water in the hot water circulation circuit 10 bypasses the first circulation tank 15 and flows into the second circulation tank 16 from the bottom via the three-way switching valve 19 and the bypass circuit 18, as shown in FIG. Then, the hot water circulation circuit 10 connected to the bottom of the circuit is short-circuited and circulated. On the other hand, the 1st circulation tank 15 will be in the state isolate | separated from the warm water circulation circuit 10 side, and the warm water of the inside passes through the low temperature water piping 4A, the three-way switching valve 7, the low temperature water piping 4, and the circulation pump 11, and the water heater 2 And heated to a predetermined temperature. The high-temperature water heated by the water heater 2 is recirculated into the first circulation tank 15 through the high-temperature water pipe 3, the three-way switching valve 6, the high-temperature water pipe 3 </ b> A, and the connection pipe 17.

  As a result, the hot water in the first circulation tank 15 can be replaced with hot water as indicated by the hatched lines in FIG. And when the 1st temperature sensor 20 and the 2nd temperature sensor 21 which are provided in the 1st circulation tank 15 detect the temperature more than preset temperature, while switching the three-way switching valve 19 from A-> C to A-> B, The operation of the water heater 2 is stopped. When the three-way switching valve 19 is switched from A → C to A → B, the high-temperature water in the first circulation tank 15 enters the second circulation tank 16 via the connection pipe 17 as shown in FIG. It moves from the top and is stored in the second circulation tank 16.

  Due to the movement of the high temperature water into the second circulation tank 16, hot water having a low temperature on the warm water circulation circuit 10 side flows into the first circulation tank 15 as indicated by hatching. As shown in FIG. 4, when this low-temperature water flows into the installation position of the first temperature sensor 20 and detects that the first temperature sensor 20 and the second temperature sensor 21 are below the set temperature, The three-way switching valve 19 is switched from A → B to A → C, and the water heater 2 starts operation again.

  As a result, as shown in FIG. 5, the first circulation tank 15 is separated from the hot water circulation circuit 10 side, and the low temperature water therein is again supplied with the low temperature water pipe 4A, the three-way switching valve 7, the low temperature water pipe. 4 and the circulation pump 11 are circulated to the water heater 2 and heated to a predetermined temperature. The high-temperature water heated by the water heater 2 is recirculated into the first circulation tank 15 through the high-temperature water pipe 3, the three-way switching valve 6, the high-temperature water pipe 3A, and the connection pipe 17, and the network shown in FIG. Hot water is stored as indicated by the line.

  On the other hand, the high-temperature water in the second circulation tank 16 is connected to the bottom of the second circulation tank 16 as it is, and the low-temperature water that has flowed into the bottom of the second circulation tank 16 through the bypass circuit 18 from the hot water circulation circuit 10 side. Since the hot water circulating circuit 10 flows out through a short circuit, the hot water is held without being circulated through the hot water circulating circuit 10. When hot water is stored in the first circulation tank 15 and the first temperature sensor 20 and the second temperature sensor 21 detect a temperature equal to or higher than the set temperature, the operation of the water heater 2 is stopped and the three-way switching valve 19 is stopped. Is switched from A → C to A → B.

  As a result, both the hot water in the first circulation tank 15 and the second circulation tank 16 can be boiled up to high temperature water that is equal to or higher than the set temperature, and the temperature of the hot water in the hot water circulation circuit 10 is kept so as not to drop below the set temperature. Can be kept. In the case of the present embodiment, as is apparent from FIG. 5, between the hot water stored in the first circulation tank 15 by the heating operation and the hot water stored in the second circulation tank 16. It is possible to operate by boiling up so that a hot water layer of low temperature water does not remain.

Thus, according to the present embodiment, the following operational effects are obtained.
When the hot water temperature in the hot water circulation circuit 10 including the first circulation tank 15 and the second circulation tank 16 is lowered, the hot water circulation circuit 10 is switched to the bypass circuit 18 side by the three-way switching valve 19, thereby the first circulation tank 15. The hot water can be circulated through the second circulation tank 16 and the hot water circulation circuit 10 by bypassing the first circulation tank 15 from the hot water circulation circuit 10 side, and the three-way switching valves 6 and 7 are switched to switch the hot water. By connecting to the hot water heater 2 via the pipes 3 and 3A and the low temperature water pipes 4 and 4A, the hot water in the first circulation tank 15 can be circulated to the hot water heater 2 to increase the boiling operation.

  Further, when the boiling of the warm water in the first circulation tank 15 is completed, the boiling operation is temporarily stopped, and the warm water circulation circuit 10 is switched from the bypass circuit 18 side to the first circulation tank 15 side by the three-way switching valve 19. Accordingly, the high-temperature water in the first circulation tank 15 can be moved to the second circulation tank 16 side, and the temperature of the high-temperature water flowing into the first circulation tank 15 from the hot-water circulation circuit 10 side is low due to the movement of the high-temperature water. When the hot water is filled, the hot water circulation circuit 10 is switched again to the bypass circuit 18 side by the three-way switching valve 19 to separate the first circulation tank 15 from the hot water circulation circuit 10 side. The hot water in the first circulation tank 15 and the second circulation tank 16 can both be boiled up to high-temperature water by circulating the hot water in the hot water supply device 2 and performing a boiling operation.

  Accordingly, the hot water in the hot water circulation circuit 10 can be maintained at a set temperature or higher at all times, and when the hot water supply terminal 9 is operated, an immediate hot water supply function that can immediately discharge hot water at a predetermined temperature or higher can be maintained. Mixing in the hot water circulation tanks 15 and 16 that circulate in the hot water circulation circuit 10 and the hot water that has been boiled is prevented, and the hot water is heated by the hot water heater 2 or the hot water that cannot be used on the load side by stabilizing the hot water storage temperature. The generation of the medium temperature water that cannot be done can be prevented.

  Further, a bypass circuit 18 that bypasses the first circulation tank 15 to circulate hot water and can separate the first circulation tank 15 from the hot water circulation circuit 10 side is connected to the hot water circulation circuit 10 and the second through a three-way switching valve 19. Since it is connected between the circulation tank 16, a circuit for coping with a decrease in hot water temperature on the hot water circulation circuit 10 side can be configured simply by adding the three-way switching valve 19 and the bypass circuit 10. Therefore, the complicated configuration and control for avoiding the mixing of the hot water circulating in the hot water circulation circuit 10 and the high-temperature water boiling in the hot water heater 2 are not required, and the circuit configuration and control system are simplified and the cost is reduced. Can be achieved.

  Furthermore, in this embodiment, while the 1st circulation tank 15 and the 2nd circulation tank 16 are connected to the connection piping 17 which connects mutual top parts, 3 A of high temperature water piping is connected, and the hot water circulation circuit 10 is each bottom part. Connected configuration. For this reason, when the temperature of the hot water in the hot water circulation circuit 10 decreases, the hot water in the first circulation tank 15 is heated up and moved to the second circulation tank 16 via the connecting pipe 17 connected between the tops. After that, when the low-temperature hot water from the hot water circulation circuit 10 side that has flowed into the first circulation tank 15 is boiled again, it flows from the bypass circuit 10 connected to the bottom on the second circulation tank 16 side. The circulating hot water can be short-circuited to the hot water circulation circuit 10 connected to the bottom as it is, and the hot water stored in the second circulation tank 16 can be held so as not to circulate.

  As a result, when the boiling of hot water in the first circulation tank 15 and the second circulation tank 16 is completed, a low temperature hot water layer remains between the first circulation tank 15 and the second circulation tank 16. Accordingly, the hot water storage temperature can be further stabilized, and both the circulation performance and the hot water supply performance can be improved.

  Further, the temperature of the hot water in the hot water circulation circuit 10 is decreased, and the first temperature sensor 20 and the second temperature sensor 21 provided in the vicinity of the top and the bottom of the first circulation tank 15 detect the temperature below the set temperature. When the hot water circulation circuit 10 is switched to the bypass circuit 18 side by the three-way switching valve 19, the first circulation tank 15 is bypassed to circulate the hot water, and the first circulation tank 15 is switched to high temperature by switching the three-way switching valves 6 and 7. It is connected to the water heater 2 through the water pipes 3 and 3A and the low-temperature water pipes 4 and 4A, and the hot water in the first circulation tank 15 can be heated and operated. The first and second temperature sensors 20 and 21 When a high temperature equal to or higher than the set temperature is detected, the heating operation is stopped and the hot water circulation circuit 10 is switched from the bypass circuit 18 side to the first circulation tank 15 side by the three-way switching valve 19. Te, it is possible to move the hot water of the first circulation tank 15 to the second circulation tank 16.

  Along with the movement of the high-temperature water, low-temperature hot water flows into the first circulation tank 15 from the hot water circulation circuit 10 side, and when the first and second temperature sensors 20 and 21 detect this, the hot water circulation circuit 10 is turned on again. The three-way switching valve 19 switches to the bypass circuit 18 side, bypasses the first circulation tank 15 and circulates hot water in the same manner as described above, and also circulates the first circulation tank 15 through the high temperature water pipes 3 and 3A and the low temperature water pipes 4 and 4A. Is connected to the hot water supply device 2 through the first, and the operation of increasing the hot water in the first circulation tank 15 is performed again. When the first and second temperature sensors 20 and 21 detect a high temperature equal to or higher than the set temperature, the operation is increased The hot water circulation circuit 10 including the first circulation tank 15 and the second circulation tank 16 is switched by switching the hot water circulation circuit 10 from the bypass circuit 18 side to the first circulation tank 15 side by the three-way switching valve 19. It is possible to maintain the hot water temperature in the circuit 10 above the set temperature.

  In this way, the hot water in the hot water circulation circuit 10 can always be kept at a set temperature or higher by simple control by simply switching the three-way switching valves 6, 7 and 19 based on the detected temperatures of the two temperature sensors 20, 21. The hot water supply function can be maintained, and mixing of the hot water boiling in the hot water heater 2 and the hot water circulating tanks 15 and 16 circulating in the hot water circulation circuit 10 is prevented, and the hot water storage temperature is reduced. It is possible to easily prevent generation of medium-temperature water that cannot be used on the load side and cannot be heated by the water heater 2.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS.
This embodiment differs from the first embodiment described above in the connection configuration of the connecting pipe 17A and the hot water circulation circuit 10 to the first circulation tank 15 and the second circulation tank 16. Since other points are the same as those in the first embodiment, description thereof will be omitted.
In the present embodiment, the first circulation tank 15 and the second circulation tank 16 connected in series in the hot water circulation circuit 10 include the top of the first circulation tank 15 and the second circulation tank, as shown in FIG. 16 is connected to the bottom of the connecting pipe 17A, and a high temperature water pipe 3A is connected to the connecting pipe 17A.

  The hot water circulation circuit 10 is connected to the bottom of the first circulation tank 15, and the hot water circulation circuit 10 is connected to the top of the second circulation tank 16, and further to the bottom of the second circulation tank 16. The bypass circuit 18 from the three-way switching valve 19 is connected.

  In this second embodiment, as shown in FIG. 6, the temperature of the hot water in the first circulation tank 15 decreases and becomes lower than the set temperature as indicated by hatching, and the first temperature sensor 20 and the second temperature When the sensor 21 detects the temperature, the three-way switching valve (switching valve) 19 is switched from A → B to A → C, and the three-way switching valves (switching valves) 6 and 7 are connected to the high-temperature water pipe 3A and the low-temperature water. It is switched to the piping 4A side, and the water heater 2 is operated. Therefore, the hot water in the hot water circulation circuit 10 bypasses the first circulation tank 15 and flows from the three-way switching valve 19 to the bottom of the second circulation tank 16 via the bypass circuit 18 as shown in FIG. The hot water circulation circuit 10 connected to the top is sequentially discharged and circulated.

  On the other hand, the 1st circulation tank 15 will be in the state isolate | separated from the warm water circulation circuit 10 side, and the warm water of the inside passes through the low temperature water piping 4A, the three-way switching valve 7, the low temperature water piping 4, and the circulation pump 11, and the water heater 2 And heated to a predetermined temperature. The high-temperature water heated by the water heater 2 is recirculated into the first circulation tank 15 via the high-temperature water pipe 3, the three-way switching valve 6, the high-temperature water pipe 3A, and the connecting pipe 17A. Hot water is stored as indicated by the shaded lines.

  As a result, as shown in FIG. 7, the hot water in the first circulation tank 15 can be replaced with high-temperature water, and the temperature of the hot water is changed to the first temperature sensor 20 and the first temperature sensor 20 provided in the first circulation tank 15. When the two-temperature sensor 21 detects and detects that the temperature is equal to or higher than the set temperature, the three-way switching valve 19 is switched from A → C to A → B, and the operation of the water heater 2 is stopped. When the three-way switching valve 19 is switched from A → C to A → B, the hot water in the first circulation tank 15 is secondly connected via a connecting pipe 17A connected to the top as shown in FIG. It moves to the bottom of the circulation tank 16 and is stored in the second circulation tank 16.

  Due to the movement of the high temperature water into the second circulation tank 16, hot water having a low temperature on the warm water circulation circuit 10 side flows into the first circulation tank 15 as indicated by hatching. As shown in FIG. 8, when this low-temperature water flows into the installation position of the first temperature sensor 20 and detects that the first temperature sensor 20 and the second temperature sensor 21 are below the set temperature, The three-way switching valve 19 is switched from A → B to A → C, and the water heater 2 starts operation again.

  As a result, as shown in FIG. 9, the first circulation tank 15 is separated from the hot water circulation circuit 10 side, and the low temperature water therein is again supplied with the low temperature water pipe 4A, the three-way switching valve 7, the low temperature water pipe. 4 and the circulation pump 11 are circulated to the water heater 2 and heated to a predetermined temperature. The high-temperature water heated by the water heater 2 is recirculated into the first circulation tank 15 through the high-temperature water pipe 3, the three-way switching valve 6, the high-temperature water pipe 3A, and the connection pipe 17A. Hot water is stored as indicated by the line.

  On the other hand, the high-temperature water in the second circulation tank 16 is pushed up to the upper side by the low-temperature water flowing from the hot water circulation circuit 10 side through the bypass circuit 18 to the bottom of the second circulation tank 16 and remains at the top. When water is caused to flow out to the hot water circulation circuit 10 and all the low-temperature water is caused to flow into the hot water circulation circuit 10, the water is circulated to the hot water circulation circuit 10. When hot water is stored in the first circulation tank 15 and the first temperature sensor 20 and the second temperature sensor 21 detect a temperature equal to or higher than the set temperature, the operation of the water heater 2 is stopped and the three-way switching valve 19 is stopped. Is switched from A → C to A → B.

  As a result, both the hot water in the first circulation tank 15 and the second circulation tank 16 can be boiled up to high temperature water that is equal to or higher than the set temperature, and the temperature of the hot water in the hot water circulation circuit 10 is kept so as not to drop below the set temperature. Can be kept. Accordingly, the present embodiment can provide substantially the same effect as that of the first embodiment. In the case of the present embodiment, as is apparent from FIG. 9, between the hot water stored in the first circulation tank 15 and the hot water stored in the second circulation tank 16 by the boiling increase operation. A small amount of the low-temperature hot water layer remains partially, but this does not greatly affect the hot water circulation function and the immediate hot water supply function of the hot water circulation circuit 10.

  In addition, this invention is not limited to the invention concerning the said embodiment, In the range which does not deviate from the summary, it can change suitably. For example, in the above embodiment, the number of hot water storage tanks 5 can be an arbitrary number, and the connection configuration between the hot water discharge pipe 8 from the hot water storage tank 5 and the hot water circulation circuit 10 can be variously modified. Further, only the basic circulation circuit is shown as the hot water circulation circuit 10, and a mixing valve or the like for adjusting temperature by mixing high temperature water and low temperature water is used for the temperature adjustment circuit and the like therein. An appropriate circuit may be adopted. Furthermore, the hot water supply terminal 9 is not limited to that of the above embodiment.

DESCRIPTION OF SYMBOLS 1 Hot water supply system 2 Water heater 3, 3A High temperature water piping 4, 4A Low temperature water piping 5, 5A, 5B, 5N Hot water storage tank 6, 7 Three-way switching valve
8 Hot water outlet 9 Hot water supply terminal 10 Hot water circulation circuit 15 First circulation tank 16 Second circulation tank 17, 17A Connection pipe 18 Bypass circuit 19 Three-way switching valve (switching valve)
20 First temperature sensor 21 Second temperature sensor

Claims (5)

A water heater for producing high-temperature water by heating low-temperature water;
A hot water storage tank connected to the hot water supply device via a hot water pipe and a low temperature water pipe, and for storing hot water produced by the water heater;
A hot water circulation circuit provided with at least one hot water supply terminal connected to the hot water pipe and the low temperature water pipe via a switching valve and connected to a hot water discharge pipe from the hot water storage tank,
The hot water circulation circuit has a pair of a first circulation tank and a second circulation tank connected to the high temperature water pipe and connected in series in the circuit,
The bottom of the first circulation tank on the upstream side and the low temperature water pipe are connected via the switching valve, and the bottom of the second circulation tank on the downstream side and the hot water circulation circuit are connected to the first circulation tank. The hot water supply system is characterized in that it is connected via a switching valve and a bypass circuit on the upstream side.   The hot water supply system according to claim 1, wherein the bypass circuit is connected between the hot water circulation circuit and the second circulation tank via the switching valve including a three-way valve.   The first circulation tank and the second circulation tank are characterized in that the hot water pipe is connected to a connecting pipe that connects the tops of the first circulation tank and the hot water circulation circuit to each bottom part. The hot water supply system according to claim 1 or 2.   The first circulation tank and the second circulation tank are connected to a connecting pipe that connects a top portion of the first circulation tank and a bottom portion of the second circulation tank, and the high-temperature water piping is connected to the first circulation tank. The hot water supply system according to claim 1 or 2, wherein the hot water circulation circuit is connected to a bottom portion and a top portion of the second circulation tank. A first temperature sensor and a second temperature sensor are provided near the top and bottom of the first circulation tank, respectively.
When the temperature of the hot water circulating in the hot water circulation circuit decreases and the first and second temperature sensors detect a temperature lower than a set temperature, the hot water circulation circuit is switched to the bypass circuit side by the switching valve, The hot water is circulated by bypassing the first circulation tank, and the first circulation tank is connected to the water heater via the high temperature water pipe and the low temperature water pipe by switching the switching valve, and the first circulation Perform hot water boiling operation in the tank,
When the first and second temperature sensors detect a high temperature that is equal to or higher than a set temperature, the heating operation is stopped, and the hot water circulation circuit is switched from the bypass circuit side to the first circulation tank side by the switching valve. , Moving hot water from the first circulation tank to the second circulation tank, and flowing hot water from the hot water circulation circuit into the first circulation tank;
When the first and second temperature sensors detect the temperature below the set temperature again, the hot water circulation circuit is switched to the bypass circuit side by the switching valve, and the hot water is circulated by bypassing the first circulation tank. The first circulation tank is connected to the hot water supply device via the high temperature water pipe and the low temperature water pipe by switching the switching valve, and the hot water is heated in the first circulation tank.
When the first and second temperature sensors again detect a high temperature equal to or higher than the set temperature, the boiling operation is stopped and the hot water circulation circuit is switched from the bypass circuit side to the first circulation tank side by the switching valve. Accordingly, the hot water in the hot water circulation circuit including the first circulation tank and the second circulation tank is configured to be maintained at a set temperature or higher. 5. Hot water system.

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