JP2015090250A - Hot water supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot water supply system that can appropriately respond to requests from a plurality of hot water use sections while using a small water heater of which operation output is small.SOLUTION: A hot water supply system includes a first water heater A and a second water heater B. A hot water use section comprises: a first hot water use group (kitchen, etc.) that is located near the first water heater A and to which hot water is supplied through hot water supply piping 2 from the first water heater A; and a second hot water use group (bathroom, etc.) that is located near the second water heater B and to which hot water is supplied through hot water supply piping 21 from the second water heater B. The hot water supply piping 2 from the first water heater A includes a first branch pipe 4, and water supply piping 1 to the first water heater A includes a second branch pipe 41. The outlet sides of the first branch pipe 4 and the second branch pipe 41 are connected to the inlet side of water supply piping 11 of the second water heater B via a mixing joint 5 including a flow control valve.

Description

  The present invention relates to a hot water supply system suitable for using hot water from a water heater in two or more hot water using sections.

  A hot water supply system comprising a hot water supply part for heating low temperature water supplied from a water supply pipe by a heat exchanger equipped with a gas burner, and hot water heated in the hot water supply part is supplied to the hot water use part through the hot water supply pipe. As described in Patent Document 1 and Patent Document 2, it has been conventionally known and implemented.

  In general households, the hot water use section can include a plurality of kitchens, toilets, washrooms, bathrooms, etc., and usually with a single water heater as described in Patent Document 1 and Patent Document 2 above. Hot water is supplied to all hot water use departments. In general, there are a plurality of water heaters such as those described in Patent Document 1 and Patent Document 2, that is, a hot water supply function to a kitchen, a hot water supply function to a bathroom, and a hot water supply function to various heating devices. Many hot water heaters (called heating bath water heaters) having the above function are used. Structurally, a main hot water supply system having a first combustion chamber, a heating system having a second combustion chamber different from the first combustion chamber, and a water-water heat exchanger (indirect heat) receiving heat supplied from the heating system. It is equipped with three systems, a follow-up system equipped with an exchanger. Hot water from the main hot water supply system is sent to kitchens, toilets, washrooms, bathrooms, etc., and hot water heated by the heating system is used for heating such as floor heating. The tub is revoked. When designing a hot water supply system, a single hot water heater can provide a large operating output so that it can meet the required output from all of the multiple hot water use sections (ie, (hot water set temperature-incoming water temperature) x water volume). It is common to install.

JP 2003-130464 A JP 2007-57137 A

  One of the hot water heaters of the type described in Patent Document 1 or Patent Document 2 is advantageous in that it can accurately respond to various and fluctuating hot water supply requests (required output) in general households. However, it is common to install a water heater with an operation output that can appropriately respond to the expected required output so as not to make the user uncomfortable. A relatively large space is required for installing the water heater. In general households, it is common for a plurality of hot water use sections to be distributed and the hot water use section located far from the location of the water heater is supplied with the required hot water after the water heater is activated. The temperature of hot water supplied from the water heater is the same even when it is unavoidable that the hot water waiting time becomes longer, that is, when hot water having different temperatures is desired in a plurality of hot water use sections. In addition, it is also necessary to mix hot water and water so as to obtain a desired temperature in each hot water use section. Furthermore, even when only one of the plurality of hot water use units requires hot water, the operation of the water heater is necessary, and it is inevitable that the operation time of the water heater as a whole becomes long.

  FIG. 10 schematically shows an example thereof. In the house A, there are a bathroom, a washroom, a toilet, and a kitchen as a hot water use part, and a single water heater is installed in the vicinity of the kitchen. The bathroom is located farthest from the water heater. As the water heater, a heating bath water heater is used, and hot water of the same temperature made by the heating bath water heater is sent to all of the bathroom, washroom, toilet, and kitchen. As described above, the heating bath water heater is supplied with heat from the main hot water supply system including the first combustion chamber, the heating system including the second combustion chamber different from the first combustion chamber, and the heating system. Assuming that the required temperature on the hot water use part side is 40 ° C, the main hot water supply system is equipped with three systems of reheating systems with water-water heat exchangers (indirect heat exchangers). The operation output is 42 kW, and the heating system generally uses a 17.4 kW water heater.

  As described above, the water heater having such a specification value is large, requires a large space for installation, and is not easy to install. In addition, since the bathroom and the water heater are separated, the hot water waiting time in the bathroom becomes long. Furthermore, all the hot water supply requests from the four hot water use units must be handled by one water heater, and it is inevitable that the operation time of the water heater becomes long. Furthermore, when the required hot water temperature of each hot water use part is different, for example, when there is a request of 60 ° C. (assuming use of a dishwasher) in the kitchen and 40 ° C. in the bathroom, the hot water heater is supplied with 60 ° C. hot water. Therefore, in the bathroom, it is necessary to mix hot water and water at 60 ° C. so that hot water at 40 ° C. comes out.

  The present invention has been made in view of the above-described circumstances inherent in a hot water supply system equipped with a hot water heater, and responds to different demands from a plurality of hot water using parts while using a small hot water heater with a small operation output. Since it is possible to answer accurately, it is possible to reduce the size of the water heater to be used, improve the installation of the water heater, and do not need a long hot water pipe, The time can be shortened, the operating time can be shortened, so the requirements for durability of the water heater can be relaxed, and hot water at different temperatures can be supplied to multiple hot water use parts Therefore, it is an object to provide a new hot water supply system with improved convenience.

  A hot water supply system according to the present invention is a hot water supply system that includes a hot water supply section that heats low temperature water supplied from a water supply pipe by a heat exchanger, and hot water heated in the hot water supply section is supplied to a hot water use section through the hot water supply pipe. The hot water supply section is composed of a first hot water heater and a second hot water heater, and the hot water use section is located in the vicinity of the first hot water heater, and hot water is supplied through the hot water supply pipe from the first hot water heater. A first hot water use group that is located near the second hot water heater and a second hot water use group in which hot water is supplied through a hot water supply pipe from the second water heater. The hot water supply pipe from the heater has a first branch pipe, the water supply pipe to the first water heater has a second branch pipe, and the outlet side of the first branch pipe and the second branch pipe Is connected to the inlet side of the water supply pipe of the second water heater through a mixing joint equipped with a flow control valve. It is characterized in.

  In the hot water supply system according to the present invention, the hot water supply requests (request outputs) from a plurality of hot water using parts are shared by the two hot water heaters. Therefore, the operation output of each water heater, that is, each of the first water heater and the second water heater, can be reduced compared to the case where it is carried by one water heater. . Since the operation output is small, the two water heaters are small compared to each other, and since the two water heaters can be arranged in a distributed manner, the installation space can be easily secured and the installation work can be facilitated. Furthermore, since the two water heaters can be arranged in a distributed manner, the distance between each water heater and each hot water use section (hot water use group) is relatively short compared to the case where a system is constructed with one water heater. Therefore, the hot water waiting time due to the length of the hot water supply pipe can be shortened. In addition, since the hot water supply requests (request output) from multiple hot water use departments are shared by the two hot water heaters, answering the request from the hot water use department with the operation of one of the hot water heaters. As a result, the total operating time of each water heater can be shortened, and the durability requirement for each water heater is relaxed. Further, in the hot water supply system according to the present invention, the hot water temperature required by the first hot water use group side (for example, 60 ° C.) and the hot water temperature required by the second hot water use group side (for example, 40 ° C.) are different. However, in the mixing joint provided with the flow control valve where the outlet side of the first branch pipe and the second branch pipe merges, the hot water from the first branch pipe and the water from the second branch pipe are mixed. By changing the ratio, it becomes possible to cope easily, and the convenience as a hot water supply system is remarkably improved.

  In the hot water supply system according to the present invention, during operation, many operating states are selected according to individual or overall hot water supply requests (request outputs) from the first hot water use group and the second hot water use group. . For example, when there is a hot water supply request from only the first hot water usage group, only the first water heater needs to be operated. When there is a hot water supply request only from the second hot water usage group, if the required output is within the maximum output of the second water heater, only the second water heater need be operated. Although the hot water supply request is only from the second hot water use group, when the required output exceeds the maximum output of the second hot water heater, the first hot water heater is activated in addition to the second hot water heater. To compensate for the shortage of output. Furthermore, when there is a hot water supply request from both the first hot water usage group and the second hot water usage group, and the total required output is within the maximum output of the first hot water heater, only the first hot water heater is used. If this is exceeded, both the first water heater and the second water heater are operated.

  In the hot water supply system according to the present invention, the form of the first and second hot water heaters is not particularly limited, and a so-called heating bath water heater described in Patent Document 1 or 2 described above can also be used. However, in the hot water supply system according to the present invention, the hot water can be supplied to both the first hot water use group and the second hot water use group or selectively using two water heaters. Taking into account the hot water demand of the hot water usage group and the second hot water usage group, by using hot water heaters with different functions as the two hot water heaters, a hot water supply system with better operational effects can be obtained. it can.

  As an example of such a hot water supply system, the first hot water use group to which hot water from the first hot water heater is supplied includes at least a kitchen, and second hot water from the second hot water heater is supplied. The hot water use group includes a bathroom, and the first water heater is a single-function water heater having only a hot water function, and the second water heater has a hot water function and a direct heat exchange function. A hot water supply system characterized by being a bath water heater provided can be given.

  In the hot water supply system of the above aspect, the first hot water heater is mainly intended for hot water supply to the kitchen. Therefore, a single-function hot water heater provided only with a conventionally known hot water supply function is sufficient. Can achieve the purpose. In addition, the second water heater is exclusively intended for hot water supply to the bath, and in this case as well, by using a bath water heater having a conventionally known hot water supply function and a reheating function by direct heat exchange, it has good thermal efficiency. You will be able to get repulse. It is also possible to use a water heater having a heating function as the first water heater, and in this case, the first hot water heater group to which hot water is supplied from the first water heater is optional such as floor heating. Heating equipment can be included.

  In any of the above-described hot water supply systems, it is preferable to use hot water heaters having the same rated output as the first hot water heater and the second hot water heater, that is, to share the hot water supply capacity. In this aspect, since the main components constituting the water heater can be shared, there is an effect of reducing the cost due to the mass production effect.

  In the hot water supply system according to the present invention, since two hot water heaters are used, it becomes possible to accurately respond to requests from a plurality of hot water using parts using a small hot water heater with a small operation output. Improved. Moreover, since a long hot water supply pipe line is not required, the hot water waiting time in the hot water use part can be shortened. Furthermore, since the hot water demand can be shared by the two water heaters, the operation time of each water heater can be shortened, and the durability requirements of the water heater can be eased. Furthermore, in the mixing joint provided with the flow control valve in which the exit side of the said 1st branch pipe and the 2nd branch pipe merges, the mixing ratio of the warm water from a 1st branch pipe, and the water from a 2nd branch pipe Since the hot water temperature supplied to the second hot water use group can be appropriately adjusted by changing the temperature, the hot water temperature supplied to the first hot water use group and the hot water temperature supplied to the second hot water use group are separately provided. It becomes possible to set, and the convenience as a hot-water supply system improves markedly.

It is a figure which shows an example of the hot water supply system by this invention, and has shown the 1st operation state (pattern A) when water supply temperature is 15 degreeC. The 2nd operation state (pattern B) when the feed water temperature is 15 degreeC in the hot-water supply system shown in FIG. 1 is shown concretely. The 3rd operation state (pattern C) when the feed water temperature is 15 degreeC in the hot-water supply system shown in FIG. 1 is shown concretely. The 1st operation state (pattern D) when the feed water temperature is 5 degreeC in the hot-water supply system shown in FIG. 1 is shown concretely. The 2nd operation state (pattern E) when the feed water temperature is 5 degreeC in the hot-water supply system shown in FIG. 1 is shown concretely. The 1st operation state (pattern G) when the feed water temperature is 25 degreeC in the hot-water supply system shown in FIG. 1 is shown concretely. The 2nd operation state (pattern G) when the feed water temperature is 25 degreeC in the hot-water supply system shown in FIG. 1 is shown concretely. The 1st figure which shows the flow at the time of the action | operation in the hot water supply system shown in FIG. The 2nd figure following the 1st figure which shows the flow at the time of the action | operation in the hot-water supply system shown in FIG. The figure explaining the conventional hot-water supply system.

  Hereinafter, an embodiment of a hot water supply system according to the present invention will be described with reference to the drawings. In the hot water supply system shown in the figure, the hot water use section is assumed to be a bathroom, a washroom, a toilet, and a kitchen, [toilet, toilet, kitchen] is set as the first hot water use group in the present invention, and [bathroom] is a book. The second hot water use group referred to in the invention. Further, the first hot water heater for supplying hot water to the first hot water use group and the second hot water heater for supplying hot water to the second hot water use group are used.

  In this example, the water heater A as the first water heater is a water heater having a hot water supply function and a heating function, and does not have a bathing function. The water heater A is supplied with clean water (tap water) from the water supply pipe 1, and is heated by a heat exchanger equipped with a gas burner (not shown) to become hot water. The hot water is discharged from the hot water / water mixing tap 3 installed in the kitchen, toilet, and washroom, which are the first hot water use group, through the hot water supply pipe 2. In the drawing, the toilet and the hot and cold water mixing tap 3 in the bathroom are omitted.

  The hot water supply pipe 2 from the hot water heater A has a first branch pipe 4 on the upstream side of the hot water mixing plug 3, and the water supply pipe 1 to the hot water heater A has a second branch pipe 41. . The outlet side of the first branch pipe 4 and the outlet side of the second branch pipe 41 are respectively connected to two inlet ports of a two-in / one-out port type mixed joint at appropriate positions. Is connected to the inlet side of the water supply pipe 11 of the water heater B which is the second water heater. Further, as shown in “Example of mechanism of mixing joint” in FIG. 8, the joint portion with the first branch pipe 4 which is one inlet port of the mixing joint 5 and the second branch which is the other inlet port. An appropriate flow control valve M is attached to the joint with the pipe 41. Therefore, when a control unit (not shown) operates the flow rate control valve M via the communication lines 50, 50, the hot water from the first branch pipe 4 or the The hot water (cold water) from the second branch pipe 41 or the hot water mixed with the hot water from the first branch pipe 4 and the upper water (cold water) from the second branch pipe 41 flows in.

  Hot water or low-temperature water supplied from the water supply pipe 11 passes through the water heater B and is heated by a heat exchanger equipped with a gas burner (not shown) to further increase the temperature. Hot water is discharged into the bathtub through a hot water supply pipe 21 from a hot-water mixing tap 31 or the like installed in the bathroom which is the second hot water use group, and is also used as hot water for showers. In this example, the hot water heater B uses a bath water heater having a hot water supply function and a reheating function by direct heat exchange.

  Below, the operation pattern of said hot-water supply system is demonstrated and divided into some use conditions. In the following description, the water heater A has a specification value of a hot water supply output capacity of 21 kW and a heating output capacity of 17.4 kW, and the water heater B has a specification value of a hot water supply output capacity of 21 kW and a reheating output capacity. 8.7 kW is used. In this case, the two hot water heaters A and B have the same hot water supply output capability (rated output) as 21 kW, and the parts can be shared.

  The pattern A shown in FIG. 1 is a pattern in which hot water supply is used only in the bathroom, and the water heater A also assists in hot water supply in the bathroom. As preconditions, the water supply temperature is 15 ° C., the hot water supply flow rate in the kitchen is 2: 0 L / min, the hot water supply temperature b in the bathroom is 40 ° C., and the hot water supply flow rate is 4:24 L / min. Under this condition, the required output on the bathroom side is (hot-water supply set temperature 40 ° C.−inlet water temperature 15 ° C.) × water volume 24 L / min = 41.9 kW, which is the conventional hot water system shown in FIG. 10, that is, one water heater. In order to satisfy this required output, a hot water heater with a specification value of hot water supply output of 42 kW is required. However, in the hot water supply system according to the present invention, both the hot water heater A and the hot water heater B with a specification value of hot water supply output of 21 kW are used. By using, the required output on the bathroom side can be answered.

  Specifically, 15 ° C. clean water flows into the water supply pipe 1 to the water heater A at a flow rate of 1:24 L / min. 12 L / min, which is 1/2 of the flow rate 1:24 L / min, enters the hot water heater A, and the hot water heater A operates with a hot water supply output capacity of 21 kW, so that hot water having a hot water temperature a of 40 ° C. is produced. In this calculation, the operation output of the water heater A is 20.9 kW.

  In this example, the hot water supply is used only in the bathroom, and the flow rate 2: in the kitchen is zero, so the hot water temperature a: all the hot water at 40 ° C., that is, the hot water at the flow rate 3:12 L / min, It flows into the branch pipe 4. The clean water having a flow rate of 12 L / min, which is the remaining half of the flow rate of 1:24 L / min, passes through the second branch pipe 41 and reaches the mixing joint 5. The two flow control valves provided on the inflow side of the mixing joint 5 are both open, and the mixing joint 5 flows through the first branch pipe 4 and the 40 ° C. warm water flowing through the second branch pipe 41 and 15. Low temperature water of ℃ joins and is mixed. The hot water having a temperature of 27.5 ° C. and a flow rate of 24 L / min as a result of mixing flows through the water supply pipe 11 of the flow rate water heater B and enters the water heater B, and the water heater B operates with a hot water supply output capacity of 21 kW. Thus, the hot water is heated to hot water having a hot water temperature b of 40 ° C. and a flow rate of 4:24 L / min. This hot water satisfies the required output on the bathroom side, and is used by users without dissatisfaction in the bathroom. At this time, the calculated operation output of the water heater B is 20.9 kW, and the total operation output of the water heater A and the water heater B is 41.8 kW.

  As described above, by adopting the hot water supply system according to the present invention, what conventionally required a hot water heater having a hot water supply output of 42 kW is used by the hot water heaters A and B having a hot water supply output of 21 kW. Can answer the output. Since the hot water supply output is approximately ½, the sizes of the water heaters A and B are small, and the installation of the water heater becomes easy. Moreover, it becomes possible to install the water heater B near the bathroom, and the hot water supply pipe from the water heater B to the bathroom is shorter than when one water heater is installed near the kitchen. Therefore, the hot water waiting time in the bathroom is greatly shortened.

  Pattern B shown in FIG. 2 is a pattern in which hot water is used in both the bathroom and the kitchen, and the water heater A assists the hot water in the bathroom. Here, the required output in the kitchen is the hot water supply temperature a: 40 ° C., the hot water flow rate 2: 8 L / min, the required output on the bathroom side is the hot water supply temperature b: 40 ° C., the hot water supply flow rate 4: 12 L / min, tap water Temperature: 15 ° C. Under this premise, the total maximum use flow rate is (12 + 8 = 20) L / min, and the water supply pipe 1 of the water heater A is supplied with clean water at a flow rate of 1:20 L / min.

  In the pattern B, the water heater A operates at almost the maximum operation output. That is, at most, 15 ° C. clean water flows into the water supply pipe 1 to the water heater A at a flow rate of 1:20 L / min, and 12 L / min out of the flow rate of 1:20 L / min enters the water heater A. Therefore, the hot water supply temperature a is 40 ° C. hot water. The calculated operation output of the water heater A at this time is 20.9 kW. Since there is a demand for a flow rate of 2: 8 L / min in the kitchen, the first branch pipe 4 has a hot water supply temperature a: 40 ° C. hot water at a flow rate of 3: (12−8 = 4) L / min. Inflow. Clean water of (20−12 = 8) L / min flows into the second branch pipe 41, and both are merged and mixed at the mixing joint 5 provided with a flow control valve. The hot water having a temperature of 23.3 ° C. and a flow rate of 12 L / min by mixing flows through the water supply pipe 11 of the flow rate water heater B and enters the water heater B, where it is heated and the hot water temperature b: 40 ° C. The flow rate is 4:12 L / min. This hot water satisfies the required output on the bathroom side, and is used by users without dissatisfaction in the bathroom. In addition, the operation output of the water heater B at this time is 14 kW, and the total operation output of the water heater A and the water heater B is 34.9 kW.

  Pattern C shown in FIG. 3 is a pattern in which hot water is used in both the bathroom and kitchen, and in addition to hot water heater A assisting in hot water in the bathroom, the hot water temperature differs between the kitchen and the bathroom. Here, the required output in the kitchen is the hot water temperature a: 60 ° C. (assuming the use of a dishwasher), the hot water flow rate is 2: 4 L / min, the required output on the bathroom side is the hot water temperature b: 40 ° C., the hot water supply The flow rate is 4:12 L / min, and the water temperature is 15 ° C. Under this premise, the total maximum usage flow rate is (4 + 12 = 16) L / min, and the water supply pipe 1 of the water heater A is supplied with clean water at a flow rate of 1:16 L / min.

  Even in the pattern C, the water heater A operates at almost the maximum operation output. That is, at most, 15 ° C. clean water flows into the water supply pipe 1 to the water heater A at a flow rate of 1:16 L / min, and 6.5 L / min out of the flow rate of 1:16 L / min is the water heater A. Then, the hot water supply temperature a: 60 ° C. becomes hot water. The calculated operation output of the water heater A at this time is 20.4 kW. Since there is a request for a flow rate of 2: 4 L / min in the kitchen, hot water at a hot water supply temperature a: 60 ° C. flows into the first branch pipe 4 at a flow rate of 3: 2.5 L / min. In addition, (16−6.5 = 9.5) L / min of clean water flows into the second branch pipe 41. Both are joined and mixed by the mixing joint 5 provided with the flow control valve. The hot water having a temperature of 24.4 ° C. and a flow rate of 12 L / min through mixing flows through the water supply pipe 11 of the flow rate water heater B and enters the water heater B, where it is heated to a hot water supply temperature b: 40 ° C. The flow rate is 4:12 L / min. This hot water satisfies the required output on the bathroom side, and is used by users without dissatisfaction in the bathroom. At this time, the calculated operation output of the water heater B is 13.1 kW, and the total operation output of the water heater A and the water heater B is 33.5 kW. Thus, in this pattern C, although hot water of 60 ° C. is supplied in the kitchen, hot water of 40 ° C. is directly supplied from the water heater B, so mixing of hot water and water on the bathroom side. It becomes unnecessary to perform.

  Next, two operation patterns of the hot water supply system according to the present invention when it is assumed that the temperature of the clean water is 5 ° C. will be described with reference to FIGS. 4 and 5. Again, the configuration of the hot water supply system is the same as that shown in FIGS.

  Pattern D shown in FIG. 4 is the same operation pattern as pattern A shown in FIG. 1, and is a pattern that uses hot water only in the bathroom and does not use hot water on the kitchen side. Here, an operation that satisfies the required output of the hot water supply temperature b in the bathroom: 40 ° C. and the hot water supply flow rate of 4: 17.2 L / min is possible. That is, since the water temperature is 5 ° C., the water heater A raises 8.6 L / min out of 17.2 L / min flowing through the water supply pipe 1 to 40 ° C. with a maximum operation output of 21 kW. be able to. The hot water temperature a flowing through the hot water supply pipe 4 is 40 ° C., that is, the hot water having a flow rate of 3: 8.6 L / min flows into the first branch pipe 4. The remaining amount of water at a flow rate of 1: 17.2 L / min, 8.6 L / min, passes through the second branch pipe 41 and reaches the mixing joint 5. In the mixing joint 5, the 40 ° C. hot water flowing through the first branch pipe 4 and the 5 ° C. low temperature water flowing through the second branch pipe 41 merge to be mixed. The hot water having a temperature of 22.5 ° C. and a flow rate of 17.2 L / min by mixing flows through the water supply pipe 11 of the flow rate water heater B and enters the water heater B, where it is heated and the hot water temperature b: 40. It becomes hot water with a flow rate of 4: 17.2 / min. This hot water satisfies the required output on the bathroom side, and is used by users without dissatisfaction in the bathroom. The calculated operation output of the water heater B at this time is 21 kW, and the total operation output of the water heater A and the water heater B is 42 kW.

  Pattern E shown in FIG. 5 is the same operation pattern as pattern B shown in FIG. 2, and is a pattern that uses hot water in both the bathroom and the kitchen, and water heater A assists in hot water in the bathroom. Here, the required output in the kitchen is the hot water supply temperature a: 40 ° C., the hot water supply flow rate 2: 8 L / min, the required output on the bathroom side is the hot water supply temperature b: 40 ° C., the hot water supply flow rate 4: 9.2 L / min, Can be operated. That is, since the water temperature is 5 ° C., the water heater A raises 8.6 L / min out of 17.2 L / min flowing through the water supply pipe 1 to 40 ° C. with a maximum operation output of 21 kW. be able to. Hot water temperature a flowing through the hot water supply pipe 2: Of the hot water at 40 ° C, the flow rate 2: 8.0 L / min goes to the kitchen side, and the hot water with the flow rate 3: 0.6 L / min flows into the first branch pipe 4. Then, the mixed joint 5 is reached. The remaining amount of water at a flow rate of 1: 17.2 L / min, 8.6 L / min, passes through the second branch pipe 41 and reaches the mixing joint 5. In the mixing joint 5, the 40 ° C. hot water flowing through the first branch pipe 4 and the 5 ° C. low temperature water flowing through the second branch pipe 41 merge to be mixed. The hot water having a temperature of 7.3 ° C. and a flow rate of 9.2 L / min as a result of mixing flows through the water supply pipe 11 of the flow rate water heater B and enters the water heater B, where it is heated and the hot water temperature b: 40 It becomes hot water with a flow rate of 4: 9.2 / min. This hot water satisfies the required output on the bathroom side, the calculated operation output of the water heater B at this time is 21 kW, and the total operation output of the water heater A and the water heater B is 42 kW. Become.

  Next, two operation patterns of the hot water supply system according to the present invention when the temperature of clean water is assumed to be 25 ° C. will be described with reference to FIGS. 6 and 7. Again, the configuration of the hot water supply system is the same as that shown in FIGS. However, since the temperature of clean water is as high as 25 ° C., further different patterns of operation modes are possible.

  Pattern F shown in FIG. 6 is a pattern that uses hot water in both the bathroom and the kitchen, but does not require bathroom assistance by hot water heater A. Here, it is assumed that the required output in the kitchen is the hot water supply temperature a: 40 ° C., the hot water supply flow rate 2: 10 L / min, and the required output on the bathroom side is the hot water supply temperature b: 40 ° C., the hot water supply flow rate 4: 20 L / min. When it does, even if it does not supply the hot water of the water heater A to a bathroom, both required output can be satisfied.

  Specifically, (20 + 10 = 30) L / min of clean water flows into the water supply pipe 1. Since the water temperature is 25 ° C., the water heater A satisfies the required output in the kitchen, the hot water supply temperature a: 40 ° C., and the hot water flow rate 2: 10 L / min with an operation output of 10.5 kW. it can. (30−10 = 20) L / min of clean water having a temperature of 25 ° C. passes through the second branch pipe 41, passes through the mixing joint 5, and flows through the water supply pipe 11 of the flow rate water heater B to supply hot water. Enter into vessel B. And it is heated there and becomes hot water with a hot water supply temperature b: 40 ° C. and a flow rate of 4:20 L / min. At this time, the calculated operation output of the water heater B is 20.9 kW, and the total operation output of the two water heaters is 31.4 kW. In this pattern, the flow control valve provided on the side of the connection portion of the mixing joint 5 with the first branch pipe 4 is closed.

  Pattern G shown in FIG. 7 is a pattern in which hot water is used only in the bathroom and hot water is not used on the kitchen side. Here, by operating only the water heater B, an operation that satisfies the required output on the bathroom side, the hot water supply temperature b: 40 ° C., and the hot water supply flow rate 4:20 L / min is possible. That is, since the water temperature is 25 ° C., the water heater B can supply hot water having a hot water temperature b of 40 ° C. and a flow rate of 4:20 L / min to the bathroom at a maximum operation output of 21 kW. Specifically, the flow rate of 1:20 L / min flowing through the water supply pipe 1 does not flow into the water heater A side, all of which passes through the second branch pipe 41 and passes through the mixing joint 5. Then, it flows through the water supply pipe 11 of the flow rate water heater B and enters the water heater B. And it is heated there and becomes hot water with a hot water supply temperature b: 40 ° C. and a flow rate of 4:20 L / min. In this pattern, the flow control valve provided on the connection portion side of the mixing joint 5 with the first branch pipe 4 is closed.

  As shown in the above-mentioned patterns A to G, in the hot water supply system according to the present invention, two water heaters that have conventionally responded to various output requirements on the user side by using a water heater with a hot water supply output of 42 kW are used. In other words, it can be seen that the use of the hot water heaters A and B having a hot water supply output of 21 kW makes it possible to answer the request. Specifically, as described above, since the hot water supply output is approximately halved, the size of the water heaters A and B becomes small, and the installation of the water heater becomes easy. Since B can be installed near the bathroom, the hot water waiting time in the bathroom can be greatly shortened. In addition, depending on the required output on the user side, it becomes possible to respond to the request by operating only one of the water heaters A and B, so that the durability requirement for each water heater is relaxed.

  Next, an example of a specific operation mode of the hot water supply system according to the present invention will be described with reference to the flowcharts shown in FIGS. 8 and 9. In the flowchart, the water heater A and the water heater B correspond to the water heater A and the water heater B in the patterns A to G described with reference to FIGS. Further, the mixing joint shown in FIG. 8 corresponds to “mixing joint 5”, “hot water side inlet” is a connection port with the outlet side of the first branch pipe 4, and “water side inlet” It is a connection port with the outlet side of the second branch pipe 41, and the “exit” is a connection port with the inlet side of the water supply pipe 11 of the water heater B.

  At the start of operation, the control unit (not shown) fully opens the flow control valve provided at the water side inlet of the mixing joint 5, that is, the connection port with the second branch pipe 41, via the communication line 50, The connection port with the first branch pipe 4 is fully closed (s1). In this state, the control unit determines whether there is a flow rate by the water amount sensor of the water heater A on the kitchen side (s2). The water amount sensor is a water amount sensor originally provided inside the water heater, and measures the amount of hot water passing through the water heater. If there is no detection by the water amount sensor of the water heater A, the process proceeds to s20.

  When the detection by the water amount sensor of the water heater A is “Yes”, it is determined whether or not there is a flow rate by the water amount sensor of the water heater B on the bathroom side (s3). If there is no detection by the water amount sensor of the water heater B, the process proceeds to step s10. When the detection by the water amount sensor of the water heater B is “Yes”, the control unit determines that hot water is used in both the kitchen, that is, the bathroom and the bathroom (s4). And a control part operates by the control similar to the conventional water heater about the water heater A (s5).

  On the other hand, the control unit determines whether or not the required output in the bathroom (= (hot water supply set temperature−water temperature) × water volume) is within the maximum output of the water heater B (s6). If it is within the maximum output, the water heater B is operated under the same control as the conventional water heater (s7). In this state, the water side inlet of the mixing joint remains fully open. An example of this operation mode is the pattern G shown in FIG. 7, and this mode mainly occurs in summer when the feed water temperature is high.

  If the maximum output is exceeded at s6, the hot water temperature cannot reach the set temperature even if the hot water heater B is operated at the maximum output (s8), and the control unit sets the hot water heater B at the maximum output. After being operated, heat is supplied also from the water heater A (note that the preset hot water supply temperature of the water heater A is maintained in advance). And the open | release ratio of the hot_water | molten_metal side inlet_port | entrance in a mixing joint is raised until the tapping temperature of the water heater B becomes set temperature (s9). An example of this operation mode is the pattern A shown in FIG. 1, and this mode occurs mainly in the winter when the feed water temperature is low.

  In s3, when there is no detection by the water amount sensor of the water heater B, the control unit determines that hot water is being used only in places other than the bathroom (s10). And by the same control with the conventional water heater, the single operation of only the water heater A is continued (even in this state, the water side inlet of the mixing joint is fully opened and the hot water side inlet is fully closed. To prepare for the start of operation of B) (s11).

  When there is no detection by the water amount sensor of the water heater A at s2, the control unit detects whether or not the flow rate is detected by the water amount sensor of the water heater B (s20). If there is a detection, it is determined that hot water is being used only in the bathroom (s21), and the control unit will continue to operate below s6. If no detection is made in s20, it is determined that hot water is not used in any place (s22), and the control unit stops the operation of the system (s23).

  It should be noted that the following table 1 summarizes the correlation between the hot water usage in the hot water supply system according to the present invention and the on / off of the two water heaters.

1 ... Water supply piping to the water heater A which is the first water heater,
11 ... Water supply piping to the water heater B which is the second water heater,
2 ... Hot water supply piping from water heater A,
21 ... Hot water supply piping from the water heater B,
3 ... Kitchen, toilet, and hot water mixing tap installed in the bathroom, which are the first hot water use group,
31 ... A hot and cold water mixing tap installed in the bathroom which is the second hot water use group,
4 ... 1st branch pipe from hot water supply pipe 2
41 ... the second branch pipe from the water supply pipe 1
5: A mixing joint provided with a flow control valve.

Claims (4)

A hot water supply system comprising a hot water supply section for heating low temperature water supplied from a water supply pipe by a heat exchanger, wherein hot water heated in the hot water supply section is supplied to the hot water use section through the hot water supply pipe,
The hot water supply unit is composed of a first water heater and a second water heater, and the hot water use unit is located in the vicinity of the first water heater, and hot water is supplied through a hot water supply pipe from the first water heater. A first hot water use group and a second hot water use group which is located near the second hot water heater and in which hot water is supplied through a hot water supply pipe from the second hot water heater. The hot water supply pipe has a first branch pipe, the water supply pipe to the first water heater has a second branch pipe, and the outlet side of the first branch pipe and the second branch pipe has a flow rate. A hot water supply system, wherein the hot water supply system is connected to an inlet side of a water supply pipe of the second water heater via a mixing joint provided with a control valve.   2. The hot water supply system according to claim 1, wherein the first hot water use group to which hot water from the first water heater is supplied includes at least a kitchen, and hot water from the second water heater is supplied thereto. The second hot water use group includes a bathroom, and the first water heater is a single-function water heater having only a hot water supply function, and the second water heater is a follow-up by a hot water supply function and direct heat exchange. A hot water supply system characterized by being a bath water heater equipped with a sowing function.   The hot water supply system according to claim 2, wherein the first water heater is a water heater further provided with a heating function.   4. The hot water supply system according to claim 1, wherein the first water heater and the second water heater are water heaters having the same rated output. 5.

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